JP2007121705A - Developing device, image forming apparatus, developing method, image forming method, and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device which is free from toner scattering and scumming of images and not only secures the amount of toner supplied but also supplies toner stably regardless of passage of time, adaptively to the increase in processing speed of an image forming apparatus, and the image forming apparatus, a developing method, an image forming method, and a process cartridge using the same. <P>SOLUTION: The developing device includes; a developer carrier 20 which holds a developer on a surface thereof and forms a magnetic brush to convey the developer; and a toner conveyance member 1 which conveys toner supplied to the developer carrier to a position facing a latent image carrier 10. The developer carrier 20 has a first voltage applying means 31 and is disposed so as to face the toner conveyance member 1, and the toner conveyance member 1 has a plurality of electrodes and a second voltage applying means 32 and is disposed so as to face the developer carrier and the latent image carrier, and the toner conveyance member is formed like a cylinder or a belt and is constituted so as to be rotated in the same direction as a toner conveyance direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a developing device including a developer carrying member for carrying a developer and a toner carrying member for carrying toner supplied from the developer carrying member, and in particular, a magnetic brush for holding the developer on the surface. Developing device for transporting toner by controlling electric field by voltage applying means each of developer carrier and toner conveying member formed and conveyed, and image forming apparatus, developing method, image forming method and process cartridge using the same About.

Conventionally, there has been known a developing device configured to perform development by supplying a developer onto a latent image carrier without directly contacting the developer on the developer carrier with the latent image carrier. There is a conventional technique in which toner is supplied onto a latent image carrier by a toner conveying device.
In this case, the toner conveying device is arranged to face the latent image carrier, and a plurality of electrodes are arranged on the surface thereof at a predetermined pitch. An n-phase AC voltage is applied to the electrode to generate a traveling wave electric field for conveying the toner, and the toner is conveyed to the surface of the latent image carrier by the traveling wave electric field.

  For example, a method has been proposed in which a toner conveying device is composed of a base member, a linear electrode array, and an AC multiphase power supply, and toner charged by a traveling electrostatic wave pattern is supplied to the image forming surface. The toner conveying device includes a rotatable brush and is configured to supply toner from a toner supply source to a base member (see, for example, Patent Document 1).

Further, a method has been proposed in which the developer precharged by the precharging means is supplied to a developer carrying body provided with a carrying electric field generating means, and the supplied developer is carried by the developer carrying body.
As one of the preliminary charging means in this case, charging is performed by using a method of rubbing the developer between the preliminary charging roller and the developer carrying body. As another preliminary charging means, a method is used in which toner and carrier are used as developers, and charging is performed by frictional contact with stirring blades. In this case, the developer is held on the surface of the sleeve roller by using a sleeve roller having a magnet roller built in, and is supplied to the developer carrying body in the state of a magnetic brush (for example, Patent Document 2). reference.).

In the above two conventional techniques, a magnetic brush roller is used as means for supplying toner to the toner conveying device. That is, the magnetic brush roller is opposed to the toner conveying device, and the toner is supplied from the magnetic brush roller. The supplied toner is conveyed to a position facing the latent image carrier by the toner conveying device. The toner supplied to the toner transport device is transported to the latent image carrier relatively easily by the transport electric field, and is developed on the latent image carrier.
Accordingly, the developing speed is determined according to the amount of toner supplied to the developing area of the latent image carrier, and how to supply a sufficient amount of toner to the latent image carrier in order to increase the speed. Will depend.

Conventionally, the amount of toner supplied to the latent image carrier is determined by the amount of toner supplied from the magnetic brush to the toner conveyance device, and the supply amount has been secured by optimizing the voltage of the conveyance device electrode and the developing bias. .
However, in the above technique, only the magnetic brush roller that has been conventionally used is applied, and the toner supply member is not considered in terms of the proper condition of toner supply accompanying the specific configuration and operation of applying the transport electric field. Therefore, there is a problem that it is impossible to stably supply toner and to stably convey toner to the latent image carrier. Further, the supply amount tends to be insufficient as the speed of the image forming apparatus increases, and there is a problem that toner is accumulated around the magnetic brush contact portion and becomes unstable with time.

On the other hand, the applicant uses a phenomenon including horizontal movement (conveyance) and vertical movement (hopping) of the powder due to electrostatic force, and the surface of the electrostatic conveyance member is moved by the phase-shift electric field. An apparatus using a developing method utilizing a phenomenon of jumping with a component in the traveling direction has been proposed.
That is, the developing device includes a conveying member that is disposed to face the latent image carrier and has a plurality of electrodes for generating a traveling wave electric field that moves the powder. Is applied to the image portion of the latent image toward the latent image carrier, and to the non-image portion, an n-phase potential is applied to form an electric field in a direction in which the powder is directed to the opposite side of the latent image carrier. The developer is supplied to the conveying member so that charged toner is directly supplied to the conveying member on the flat plate (see, for example, Patent Document 3).

  Based on the above, it is possible to stably supply the toner to the conveying member that conveys the toner by the phase-shift electric field. However, the supply is not always sufficient for the increase in the toner amount accompanying the increase in the speed of the image forming apparatus, and further improvement in the conveyance amount is desired.

JP 60-257461 A JP-A-3-21967 JP 2004-198675 A

  The present invention has been made in view of the above prior art, and in a developing device using a developer carrier (magnetic brush roller) as means for supplying toner to a toner conveying device, toner scattering and image smearing. The present invention has an object to provide a developing device that can ensure the supply amount of toner according to the speeding up of the image forming apparatus and achieve stable supply over time, and an image forming apparatus, a developing method, and image formation using the developing device It is an object to provide a method and a process cartridge.

That is, the present invention relates to a developer carrying member that holds a developer on the surface and forms a magnetic brush and conveys it, and a toner that conveys toner supplied from the developer carrying member to a position facing the latent image carrying member. In a developing device including a conveying member,
The developer carrying member is disposed to face the toner conveying member, and has a first voltage applying means for applying a voltage to the developer carrying member,
The toner transport member has a plurality of electrodes for forming a transport electric field, and is disposed to face the developer carrier and the latent image carrier, respectively, and applies a voltage to the toner transport member and the electrodes of the toner transport member. A developing device having a second voltage applying means for applying and having a cylindrical shape or a belt shape and rotating in the same direction as the toner conveying direction.

  By the developing device having the above-described configuration, high-quality development is achieved without toner scattering and background contamination, and the toner accompanying the increase in the speed of the image forming apparatus by rotating the toner conveying member in the same direction as the toner conveying direction. The supply amount is secured without shortage, and the toner is stably supplied over time.

  In the developing device, the developer may be a two-component developer including a magnetic carrier and a nonmagnetic toner.

  The two-component developer has better toner charging stability than the one-component developer. By using the two-component developer, a magnetic brush is suitably formed on the surface of the developer carrying member, and the toner is hopped well. And can be transported. In addition, toner recovery can be performed well.

  According to the present invention, in any one of the developing devices described above, the magnetic brush formed of the developer held on the surface of the developer carrying member at a position where the developer carrying member and the toner carrying member face each other, It contacts the member.

  By contacting the rotating toner conveying member and the magnetic brush at a position where the magnetic brush keeps changing, the collected toner is efficiently electrostatically adsorbed to the carrier, and is scavenged and collected by the developer agitating unit, thus preventing toner retention. be able to.

  According to the present invention, in any one of the developing devices described above, in the position where the developer carrying member and the toner conveying member face each other, the toner conveying direction that is the same as the rotation direction of the toner conveying member, The developer supply direction by the developer carrier is opposite to that of the developer carrier.

  By reversing the toner transport direction and the developer supply direction, for example, the toner dissociated from the carrier of the two-component developer is efficiently captured in the transport electric field without being captured again by the carrier or developer carrier. Can be carried on board.

  According to the present invention, in any one of the above developing devices, the voltage applied to the developer carrying member by the first voltage applying unit is determined by the ratio between the potential difference between the developer carrying member and the toner conveying member and the distance. The magnitude of the electric field is such that the second voltage applying means is smaller than the magnitude of the electric field determined by the ratio of the voltage applied to the toner conveying member and the distance between the electrodes of the toner conveying member. And

  By controlling the electric field generated by the applied voltage of the first voltage applying unit and the applied voltage of the second voltage applying unit, the toner moved from the developer carrier to the toner conveying member at a low voltage is conveyed by the conveying electric field. Toner adhesion at the toner supply unit can be suppressed.

  In the developing device, the voltage applied by the first voltage applying unit to the developer carrying member is a voltage in which an AC voltage is superimposed on a DC voltage.

  The electric field generated by the AC voltage makes it easier for the toner to move from the developer carrier to the toner conveying member, and the amount of toner supply increases. Further, toner adhesion to the surface of the toner conveying member can be suppressed.

  In the developing device according to the present invention, the AC component of the voltage applied to the developer carrier by the first voltage applying unit is a rectangular wave.

  By making the alternating current component of the applied voltage of the first voltage applying means a rectangular wave, an abrupt electric field change occurs between the developer carrying member and the toner carrying member, and the toner is transferred from the developer carrying member to the toner carrying member. The amount of toner can be increased by moving.

  Furthermore, the present invention relates to an image forming apparatus including any one of the developing devices described above.

  According to the image forming apparatus having the above configuration, since any one of the developing devices described above is provided, there is no scattering of toner, background contamination, etc., and securing of the toner supply amount accompanying the increase in speed and stable supply over time are achieved. As a result, the image quality can be improved, and the size and cost of the apparatus can be reduced.

The present invention also provides a developer carrying member that holds the developer on the surface and forms a magnetic brush and conveys the toner, and a toner that conveys toner supplied from the developer carrying member to a position facing the latent image carrying member. A conveying member,
The developer carrying member is disposed to face the toner carrying member, and has first voltage applying means for applying a voltage to the developer carrying member, and the toner carrying member has a plurality of members for forming a transport electric field. And a second voltage applying means for applying a voltage to the electrode of the toner carrying member and the toner carrying member, and the toner carrying member and the latent image carrying body. The development is characterized in that the conveying member is cylindrical or belt-like and is developed by attaching toner to the latent image on the latent image carrier by a developing device configured to rotate in the same direction as the toner conveying direction. It concerns the method.

  According to the above developing method, by rotating the toner conveying member in the same direction as the toner conveying direction, it is possible to stably supply the toner accompanying the increase in speed and to collect the toner efficiently. Further, since the toner is pulled back in the area after passing through the development area, the scattering of the toner can be reduced, and the development quality is improved.

  Furthermore, the present invention relates to an image forming method using the above-described developing method.

  According to the above image forming method, low voltage driving is possible, high quality development can be performed with high development efficiency, toner scattering can be more reliably suppressed, and high quality images can be obtained even at high speed. Can be formed.

  The present invention also relates to a process cartridge characterized in that at least one of a latent image carrier, a charging unit, and a cleaning unit in an electrophotographic process and the developing device described above are integrally held. It is.

  According to the process cartridge having the above configuration, low voltage driving is possible, and high-quality development can be performed with high development efficiency. In addition, the apparatus can be reduced in size and maintainability can be improved, and can be easily exchanged with another apparatus.

  Furthermore, the present invention relates to an image forming apparatus comprising the process cartridge described above.

According to the image forming apparatus provided with the process cartridge, there is no scattering of toner, background contamination, etc., ensuring of the toner supply amount accompanying the increase in speed and stable supply over time can be achieved, and the image quality can be improved. In addition, the maintainability is good, and the apparatus can be reduced in size and cost.
Further, by forming an image forming apparatus including a plurality of the process cartridges, it is possible to form full color images at a higher speed.

The developing device according to the present invention provides a developing device with high development quality that can secure a toner supply amount accompanying the increase in the speed of the image forming apparatus and can stably supply the toner over time. Further, since development can be performed at a low voltage by electric field control, the durability of the latent image carrier is improved and environmental problems can be avoided.
According to the image forming apparatus of the present invention, the image quality can be improved even in high-speed image formation, and the apparatus can be reduced in size and cost.
According to the developing method of the present invention, it is possible to stably supply toner accompanying the increase in speed and to perform high-quality development with high development efficiency.
According to the image forming method of the present invention, a high-quality image can be formed even at a high speed by high-quality development such as low voltage driving and toner scattering suppression.
According to the process cartridge of the present invention, it is possible to improve maintainability and reduce the size of the apparatus.
According to the image forming apparatus including the process cartridge according to the present invention, the image quality can be improved in high-speed image formation.

As described above, the developing device according to the present invention has a developer carrying member that holds a developer on the surface and forms a magnetic brush and conveys it, and toner supplied from the developer carrying member faces the latent image carrying member. In a developing device including a toner conveying member that conveys to a position,
The developer carrying member is disposed to face the toner carrying member, and has first voltage applying means for applying a voltage to the developer carrying member, and the toner carrying member has a plurality of members for forming a transport electric field. And a second voltage applying means for applying a voltage to the electrode of the toner carrying member and the toner carrying member, and the toner carrying member and the latent image carrying body. The conveying member has a cylindrical or belt shape and is configured to rotate in the same direction as the toner conveying direction.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
First, a first embodiment of a developing device according to the present invention will be described with reference to FIGS. 1 (a) and 1 (b). FIG. 1 is a schematic configuration diagram of the developing device.

  In the following description, the movement of the toner due to the electrostatic force from the electric field from the developer carrier to the toner conveying member is expressed as “movement” or “supply”, and the amount of the toner is expressed as “supply amount”. is doing. The movement of the toner supplied (moved) to the toner conveying member on the surface of the toner conveying member by a conveying electric field is expressed as “conveying”, and the amount of toner conveyed is expressed as “conveying amount”. . Naturally, when the supply amount decreases, the transport amount also decreases. Also, the amount of conveyance is reduced when the toner is supplied to the toner conveying member but is not conveyed and the toner adheres to the surface of the toner conveying member. In order to simply express “transport”, it may be expressed as “transport”.

  1A is divided into two chambers, which are connected by developer passages (not shown) at both ends in the developing device. Two-component developer (carrier + toner) is accommodated in the developer accommodating portion 24 and is conveyed through the developer accommodating portion while being agitated by the agitating and conveying screws 25A and 25B in the respective chambers. A toner supply port 26 is disposed in the developing device, and the developer storage unit 24 is supplied through a toner supply port from a toner storage unit (not shown).

  A toner concentration sensor (not shown) that detects the magnetic permeability of the developer is installed in the developer accommodating portion 24 to detect the concentration of the developer. When the toner concentration in the developer accommodating portion decreases, toner is replenished from the toner replenishing port to the developer accommodating portion.

  A developer carrier 20 is disposed at a position facing the agitating and conveying screw 25A. A fixed magnet is disposed inside the developer carrier 20, and the developer in the developer container is pumped up to the surface of the developer carrier by the rotation and magnetic force of the developer carrier. A developer layer regulating member 27 is provided at a position facing the developer carrier upstream of the developer pumping position upstream in the rotation direction of the developer carrier.

  The developer pumped up at the pumping position is regulated to a certain amount of developer layer thickness by the developer layer regulating member 27. The developer that has passed through the developer layer regulating member 27 moves to a position facing the toner conveying member 1 as the developer carrying member 20 rotates. The developer pumped and held on the surface of the developer carrier 20 forms a magnetic brush and is supplied to the toner conveying member 1.

  A supply bias is applied to the developer carrier 20 by the first voltage application means 31. A voltage is applied to the toner conveying member 1 by the second voltage applying means 32. At a position facing the toner conveying member 1, an electric field is generated between the toner conveying member 1 and the developer carrier 20 by the first and second voltage applying means. Under the electrostatic force from the electric field, the toner dissociates from the carrier and moves to the surface of the toner conveying member. The toner that has reached the surface of the toner transport member is transported while hopping on the surface of the toner transport member by the transport electric field generated by the voltage applied by the second voltage applying unit 32.

  Here, the voltage applied by the first voltage application means 31 to the developer carrier 20 is such that the magnitude of the electric field determined by the ratio between the potential difference and the distance between the developer carrier 20 and the toner conveying member 1 is the first. It is preferable that the voltage be smaller than the magnitude of the electric field determined by the ratio of the voltage applied to the toner conveying member 1 by the two voltage applying means 32 and the distance between the electrodes of the toner conveying member.

The magnitude of the electric field generated between the developer carrying member 20 and the toner conveying member 1 by the voltage applied by the first voltage applying means 31 depends on the voltage applied by the second voltage applying means 32 and the electrode of the toner conveying member 1. When the magnitude of the transport electric field generated between them is larger, the transport electric field does not effectively act on the toner, and the toner moved from the developer carrying member 20 to the toner transport member 1 is not transported and stays there. The toner cannot be supplied to the latent image carrier 10.
The magnitude of the electric field generated between the developer carrying member 20 and the toner conveying member 1 is smaller than the magnitude of the conveying electric field generated between the electrodes of the toner conveying member 1 due to the voltage applied by the second voltage applying unit 32. By applying such a voltage by the first voltage applying means 31, the toner moved from the developer carrying member 23 to the toner conveying member 1 can be conveyed by the conveying electric field, and toner adhesion at the toner supply unit is suppressed. can do.

Further, the voltage applied by the first voltage applying means 31 to the developer carrier 20 is preferably a voltage obtained by superimposing an AC voltage on a DC voltage.
If the voltage applied by the first voltage applying means 31 is a voltage obtained by superimposing an AC voltage on a DC voltage, the toner vibrates due to an electric field generated by the AC voltage. Due to the vibration, the toner is easily dissociated from the carrier, and the toner is easily moved from the developer carrying member 20 to the toner conveying member 1, thereby increasing the amount of toner supplied. In addition, the toner adhering to the surface of the toner conveying member 1 also has a weak electrostatic adhering force due to the fluctuation of the electric field, so that the toner adhering to the surface of the toner conveying member can be suppressed.

Further, the AC component of the voltage applied to the developer carrier 20 by the first voltage applying means 31 is preferably a rectangular wave.
By making the AC component of the voltage applied to the developer carrier 20 by the first voltage application means 31 into a rectangular wave, the magnitude of the electric field between the developer carrier 20 and the toner conveying member 1 is rapidly changed. be able to. The toner moves from the developer carrier 20 to the toner conveying member 1 due to the sudden change in electric field. Therefore, the amount of toner supply can be increased by using a rectangular wave as the AC component.

  FIG. 1B shows a portion where the toner conveying member 1 and the latent image carrier (photosensitive drum) 10 of the developing device face each other. The developing device includes a toner transport member 1 having a plurality of electrodes 102 for generating an electric field for transporting, hopping, and collecting toner T, which is powder, and each of the electrodes 102 of the toner transport member 1 Thus, different drive waveforms Va1 to Vc1 and Va2 to Vc2 of n phases (here, three phases) for generating a required electric field from the drive circuit 2 arranged in the second voltage application means 32 are applied. The

  Here, the toner conveying member 1 transfers the toner T to the vicinity of the photosensitive drum 10 in relation to the range of the electrode 102 that gives the driving waveforms Va1 to Vc1 and Va2 to Vc2 and the photosensitive drum 10 that is a latent image carrier. A transport region 11 to be formed, a development region 12 for forming a toner image by attaching toner T to the latent image on the photosensitive drum 1, and a region after passing through the development region for collecting the toner T on the transport substrate 1 side ( This is hereinafter referred to as “collection area”) 13.

  The developing device transfers the toner T to the vicinity of the photosensitive drum 10 in the conveyance region 11 of the toner conveying member 1, and the toner T for the image portion of the latent image on the photosensitive drum 10 in the development region 12. Is directed to the photosensitive drum 10 side, and an electric field is formed on the non-image portion in a direction in which the toner T is directed to the side opposite to the photosensitive drum 10 (conveying substrate side), thereby attaching the toner T to the latent image. In the recovery area 13, the toner T is directed in the direction toward the opposite side (conveying substrate side) from the photosensitive drum 10 with respect to both the image portion and the non-image portion of the latent image. Create an electric field.

  As a result, in the developing region 12, the toner adheres to the latent image on the latent image carrier (photosensitive drum) 10 to be visualized, and the toner that has not contributed to the development rotates (moves) the photosensitive drum 10. Direction) Since the toner is collected on the conveyance base material 1 side in the collection region 13 on the downstream side, generation of scattered toner is prevented. The collection area 13 is located downstream of the development area 12 in the moving direction of the latent image carrier 10, so that the floating toner can be reliably collected.

As described above, the toner conveying member 1 of the present invention has a cylindrical or belt shape and is configured to rotate in the same direction as the toner conveying direction.
In the case of a conventional toner conveying member having a fixed structure, the amount of toner supplied to the latent image carrier 10 is determined by the amount of toner supplied from the magnetic brush to the toner conveying device. By rotating the toner conveying member 1 of the present invention in the same direction as the toner conveying direction, it is possible to increase the amount of toner supplied onto the latent image carrier per unit time, and accordingly the speed can be increased. became. In addition, since the toner conveying member rotates and the position of contact with the magnetic brush changes, toner recovery is performed efficiently and toner retention can be prevented.

  In the present invention, any developer can be used as long as the developer is held on the surface of the developer carrying member and can be conveyed by forming a magnetic brush. In particular, the developer carrier includes a magnetic carrier and a non-magnetic toner. It is preferable to use a two-component developer. The two-component developer has better toner charging stability than the one-component developer. By using the two-component developer, a magnetic brush is suitably formed on the surface of the developer carrying member, and the toner is hopped well. And can be transported. In other words, toner charging stability is the most important factor for hopping and transporting toner. In addition, it plays an important role in toner collection described later.

The present invention is characterized in that the magnetic brush formed of the developer held on the surface of the developer carrying member is in contact with the toner carrying member at a position where the developer carrying member and the toner carrying member face each other.
A conventional developing device with a fixed conveying member requires a mechanism for collecting the toner that has been conveyed from the collection area to the contact portion with the magnetic brush. Attempts have also been made to provide the magnetic brush with a mechanism for achieving both toner collection and supply. However, the toner conveyed from the collection area accumulates in the vicinity of the contact portion with the magnetic brush, and the staying toner remains in the development area. There was a problem that this process failed over time.

  As the toner conveying member continues to rotate and the contact position with the magnetic brush continues to change as in the configuration of the present invention, the collected toner is efficiently electrostatically adsorbed to the carrier and scavenged and collected by the developer agitating unit, and a separate collecting mechanism is provided. It is possible to prevent stagnant toner without being provided.

  At that time, the toner coverage of the carrier in the developer is preferably 30 to 70%. This is because if 70% or more, the collecting ability tends to be insufficient, and if it is 30% or less, the amount of toner supplied to the toner conveying member supply area decreases.

In the present invention, at the position where the developer carrying member 20 and the toner carrying member 1 face each other, the toner carrying direction by the toner carrying member 1 (same as the rotation direction of the toner carrying member) and the development by the developer carrying member 20 are used. The agent supply direction is reversed.
By reversing the toner transport direction and the developer supply direction, the toner dissociated from the carrier (two-component developer) is placed on the transport electric field without being captured by the carrier or developer carrier 20 again. It is because it can convey.

  First, the configuration of the toner conveying member 1 in the developing device shown in FIG. 1 will be described in detail with reference to FIGS. 2 is a developed plan view for explaining the configuration of the toner conveying member (cylindrical or belt-like) in FIG. 1, FIG. 3 is a sectional view taken along line AA in FIG. 2, and FIG. 2 is a cross-sectional view taken along line BB in FIG. 2, FIG. 5 is a cross-sectional view taken along line CC in FIG. 2, and FIG. 6 is a cross-sectional view taken along line DD in FIG.

  The toner conveying member 1 includes three electrodes (conveying electrodes) 102a, 102b, and 102c (these are also collectively referred to as “electrodes 102”) on a base substrate (supporting substrate) 101 as a predetermined set. At intervals, it is repeatedly formed and arranged in a direction substantially perpendicular to the toner transfer direction along the toner transfer direction (toner traveling direction, toner moving direction: indicated by the arrow in FIGS. 2 and 3), and a conveying surface thereon A surface protective layer 103 made of an inorganic or organic insulating material that is a protective film covering the surface of the electrode 102 is laminated. Here, the surface protective layer 103 forms the transport surface, but a surface layer having excellent compatibility with the powder (toner) can be additionally formed on the surface protective layer 103.

  On both sides of these electrodes 102a, 102b, 102c, common electrodes 105a, 105b, 105c (these are also collectively referred to as “common electrode 105”) interconnected with the electrodes 102a, 102b, 102c at both ends, respectively, are transported with toner. It is provided along the direction, that is, in a direction substantially orthogonal to the individual electrodes. In this case, the width of the common electrode 105 (this width is the width in the direction orthogonal to the toner transfer direction) is larger than the width of the electrode 102 (this width is the width along the toner transfer direction). In FIG. 2, the common electrode 105, the common electrodes 105a1, 105b1, and 105c1 in the transport region 11, the common electrodes 105a2, 105b2, and 105c2 in the development region 12, and the common electrodes 105a3, 105b3, and 105c3 in the recovery region 13, It is shown separately.

  Here, after the pattern of the common electrodes 105a, 105b, and 105c is formed on the support substrate 101, an interlayer insulating film 107 (which may be the same material as the surface protective layer 103 or a different material) is formed, and this interlayer insulation is formed. After the contact hole 108 is formed in the film 107, the electrodes 102a, 102b, and 102c are formed to interconnect the electrodes 102a, 102b, and 102c and the common electrodes 105a, 105b, and 105c, respectively.

  An interlayer insulating film is formed on a pattern in which the electrode 102a and the common electrode 105a are integrally formed, a pattern in which the electrode 102b and the common electrode 105b are integrally formed is formed on the interlayer insulating film, and an interlayer insulating film is further formed. Thus, a pattern in which the electrode 102c and the common electrode 105c are integrally formed is formed on the interlayer insulating film, that is, the electrode can be formed in a three-layer structure, or the integral formation and the interconnection by the contact hole Can also be mixed.

  Further, although not shown, these common electrodes 105a, 105b, 105c are provided with drive signal application input terminals for inputting drive signals (drive waveforms) Va, Vb, Vc from the drive circuit 2. This drive signal input terminal may be provided on the back surface side of the support substrate 101 and connected to the common electrode 105 through a through hole, or may be provided on an interlayer insulating film 107 described later.

Here, as the support base 101, a base made of an insulating material such as a cylindrical glass base, a resin base or a ceramic base, or a base made of a conductive material such as SUS or aluminum is used. _A base belt made of a material that can be deformed flexibly such as a polyimide film or the like can be used.

  For the electrode 102, a conductive material such as Al or Ni—Cr is formed on the support substrate 101 with a thickness of 0.1 to 10 μm, preferably 0.5 to 2.0 μm, and this is formed using a photolithography technique or the like. The pattern is formed into a required electrode shape. The width L in the powder traveling direction of the plurality of electrodes 102 is 1 to 20 times the average particle diameter of the powder to be moved, and the distance R in the powder traveling direction of the electrodes 102 and 12 is also moved. The average particle size of the body is 1 to 20 times.

As the surface protective layer 103, for example, SiO ₂ , TiO ₂ , TiO ₄ , SiON, BN, TiN, Ta ₂ O _5, etc. are formed to a thickness of 0.5 to 10 μm, preferably 0.5 to 3 μm. Formed. In addition, inorganic nitride compounds such as SiN, Bn, and W can be used. In particular, since the charge amount of the charged toner tends to decrease in the middle of conveyance when the surface hydroxyl groups increase, inorganic nitride compounds with few surface hydroxyl groups (SiOH, silatol groups) are preferable.

Next, the principle of electrostatic conveyance of toner in the toner conveyance member 1 configured as described above will be described.
By applying an n-phase driving waveform to the plurality of electrodes 102 of the toner conveying member 1, a phase shift electric field (traveling wave electric field) is generated by the plurality of electrodes 102, and the charged toner on the toner conveying member 1 is In response to the repulsive force and / or suction force, it moves in the transfer direction including hopping and conveyance.

  For example, as shown in FIG. 7, with respect to the plurality of electrodes 102 of the toner conveying member 1, a three-phase pulse-like driving waveform (driving signal) Va (A) that changes between the ground G (0 V) and the positive voltage + is shown. Phase), Vb (B phase), and Vc (C phase) are applied at different timings.

  At this time, as shown in FIG. 8, there is negatively charged toner T on the toner conveying member 1, and “G”, as shown in FIG. If “G”, “+”, “G”, and “G” are applied, the negatively charged toner T is positioned on the “+” electrode 102.

  At the next timing, “+”, “G”, “G”, “+”, and “G” are respectively applied to the plurality of electrodes 102 as shown in (2). Since a repulsive force acts between the left “G” electrode 102 and an attractive force acts between the right “+” electrode 102, the negatively charged toner T moves to the “+” electrode 102 side. To do. Further, as shown in (3), “G”, “+”, “G”, “G”, “+” are respectively applied to the plurality of electrodes 102 at the next timing, and the same applies to the negatively charged toner T. Therefore, the negatively charged toner T further moves to the “+” electrode 102 side.

  In this way, by applying a multi-phase driving waveform whose voltage changes to the plurality of electrodes 102, a traveling wave electric field is generated on the toner conveying member 1, and the negatively charged toner T is moved in the traveling direction of the traveling wave electric field. Move while carrying and hopping. In the case of positively charged toner, the drive waveform changes in the same direction by reversing the drive waveform change pattern.

  This will be specifically described with reference to FIG. 9. As shown in FIG. 9A, the electrodes A to F of the toner conveying member 1 are all 0 V (G), and the negatively charged toner is placed on the toner conveying member 1. When “+” is applied to the electrodes A and D from the state where T is placed, the negatively charged toner T is attracted to the electrodes A and D as shown in FIG. Move on. At the next timing, as shown in FIG. 5C, when the electrodes A and D are both “0” and “+” is applied to the electrodes B and E, the toner T on the electrodes A and D is displayed. Receives the repulsive force and the suction force of the electrodes B and E, so that the negatively charged toner T is transferred to the electrode B and the electrode E. Furthermore, at the next timing, as shown in FIG. 4D, when the electrodes B and E are both “0” and “+” is applied to the electrodes C and F, The toner T receives a repulsive force and also receives the suction force of the electrodes C and F, so that the negatively charged toner T is transferred to the electrodes C and F. In this way, the negatively charged toner is sequentially transferred rightward in the drawing by the traveling wave electric field.

  Next, the overall configuration of the drive circuit 2 will be described with reference to FIG. The drive circuit 2 includes a pulse signal generation circuit 21 that generates and outputs a pulse signal, and waveform amplifiers 22a and 22b that generate and output drive waveforms Va1, Vb1, and Vc1 by inputting the pulse signal from the pulse signal generation circuit 21. 22c, and waveform amplifiers 23a, 23b, and 23c that receive the pulse signals from the pulse signal generation circuit 21 and generate and output the drive waveforms Va2, Vb2, and Vc2.

  The pulse signal generation circuit 21 receives, for example, logic level input pulses, and includes two sets of pulses that are phase-shifted by 120 °, and switches switching means such as transistors included in the next-stage waveform amplifiers 22a to 22c and 23a to 23c. It generates and outputs a pulse signal having an output voltage of 10 to 15 V that can be driven to perform switching of 100 V.

  For example, as shown in FIG. 11, the waveform amplifiers 22a, 22b, and 22c apply an application time ta of +100 V for each phase to each electrode 102 in the transport region 11 and each electrode 102 in the recovery region 13 shown in FIG. Three-phase driving waveforms (driving pulses) Va1, Vb1, and Vc1 are applied, which is set to about 33%, which is 1/3 of the repetition period tf (this is referred to as “carrier voltage pattern” or “collected carrier voltage pattern”). .

  For example, as shown in FIG. 12 or FIG. 13, the waveform amplifiers 23a, 23b, and 23c repeat the application time ta of + 100V or 0V for each phase at 2/3 of the cycle tf. Three-phase drive waveforms (drive pulses) Va2, Vb2, and Vc2 that are set to about 67% (this is referred to as “hopping voltage pattern”) are applied.

  Therefore, the principle of EH development using the toner conveying member 1 will be described. EH (Electrostatic Transport & Hopping) development uses electrostatic transport of toner. However, like conventional developing devices using electrostatic transport, toner is naturally smoked along with electrostatic transport. Instead of developing using the cloud, toner is positively launched toward the latent image carrier for development. Hereinafter, EH development will be described in detail.

  In EH development, an electrostatic latent image on a latent image carrier can be developed by a one-component development method by hopping toner. That is, in the development area, means for forming an electric field in a direction in which the toner is directed to the latent image carrier side with respect to the image portion of the latent image and the toner is directed to the opposite side of the latent image carrier body with respect to the non-image portion. By providing, development can be performed.

  For example, in the case of a pulsed voltage waveform transitioning from 0 to −100 V as in the driving waveform of the hopping voltage pattern shown in FIG. 13 described above, when the non-image portion potential on the latent image carrier is lower than −100 V, For the image portion, the toner is directed to the latent image carrier, and for the non-image portion, the toner is directed to the opposite side of the latent image carrier. In this case, it was confirmed that when the potential of the non-image portion of the latent image is −150V or −170V described later, the toner moves toward the latent image carrier.

Further, when the driving waveform of the hopping voltage pattern is a pulsed voltage waveform that transitions between 20 V and −80 V, the pulsed driving waveform is also obtained when the potential of the image portion is about 0 V and the potential of the non-image portion is −110 V. Similarly, since the low level potential is between the image portion potential of the latent image and the non-image portion potential, the toner is directed toward the latent image carrier for the image portion and the toner is applied to the non-image portion. It goes to the opposite side to the latent image carrier.
In short, by setting the low-level potential of the pulse-shaped drive waveform to a potential between the potential of the latent image portion and the non-image portion, toner adhesion to the non-image portion is prevented and high quality is achieved. Development can be performed.

  In this way, in the EH development, since toner is hopping, the toner is attracted and adhered to the image portion of the latent image, and the toner is repelled and not adhered to the non-image portion. At this time, since the toner that has already been hopped does not generate an adsorbing force with the toner conveying member 1, it can be easily transferred to the latent image carrier and high image quality can be obtained. Development can be performed at a low voltage.

  That is, in the conventional so-called jumping development method, in order to peel off the charged toner from the developing roller and transfer it to the photosensitive member, an applied voltage higher than the adhesion force of the toner to the developing roller is required. A bias voltage must be applied. On the other hand, according to the present invention, the adhesion force of the toner is usually 50 to 200 nN, but since the adhesion force to the toner conveyance member 1 becomes substantially zero because of hopping on the toner conveyance member 1, The force for separating the toner from the toner conveying member 1 becomes unnecessary, and the toner can be sufficiently transferred to the latent image carrier side at a low voltage.

  In addition, even when the voltage applied between the electrodes 102 and 102 is a low voltage of | 150 to 100 | V or less, the generated electric field has a very large value, and the toner adhering to the surface of the electrode 102 is easily peeled off. It is possible to fly, hop. Further, ozone and NOx generated when charging a photoconductor such as OPC are very little or can be eliminated, which is very advantageous for avoiding environmental problems and improving the durability of the photoconductor.

  Therefore, there is no need for a high voltage bias of 500 V to several KV applied between the developing roller and the photosensitive member in order to peel off toner adhering to the surface of the conventional developing roller or carrier. The latent image can be formed and developed by setting the charging potential of the photosensitive member to a very low value.

For example, in FIG. 1, an OPC photoconductor is used as the latent image carrier 10, the surface CTL (Charge Transport Layer) thickness is 15 μm, the relative dielectric constant ε is 3, and the charge density of the charged toner is (− In the case of 3E-4) C / m ² , the OPC surface potential is about −170 V. In this case, the applied voltage to the electrode of the toner conveying member 1 is 0 to −100 V, and a pulse-like driving voltage with a duty of 50%. Is applied, the average becomes −50 V, and if the toner is negatively charged, the electric field between the electrode of the toner conveying member 1 and the OPC photosensitive member has the relationship described above.

  At this time, if the gap (interval) between the toner conveying member 1 and the OPC photosensitive member is 0.2 to 0.3 mm, the development can be sufficiently performed. Depending on the Q / M of the toner, the voltage applied to the electrode of the toner conveying member 1, the printing speed, that is, the rotational speed of the latent image carrier (photoconductor), in the case of negatively charged toner, at least the potential for charging the photoconductor is In the case of a configuration in which priority is given to −300 V or less, or development efficiency, sufficient development can be performed even at −100 V or less. Note that the charging potential in the case of positive charging is a positive potential.

  By the way, the above-described EH development is performed by causing toner to hop on the toner conveying member 1 so that the adsorbing force with the toner conveying member 1 is zero. If the toner is simply hopped on the toner conveying member, the hopped toner is surely attached to the latent image on the latent image carrier 10 even if the toner has progress toward the latent image carrier. It was also confirmed that the toner was scattered without being guaranteed.

  Therefore, as a result of earnest research on the EH development, the present inventors have selectively and reliably adhered the hopped toner to the image portion of the latent image carrier and not to the non-image portion. That is, the present inventors have found a condition that does not cause soiling.

  That is, the relationship between the latent image potential (surface potential) of the latent image carrier and the potential applied to the toner conveying member (generated electric field) is set to a predetermined relationship, that is, as described above, the latent image carrier. For the image portion of the latent image, an electric field is generated for the toner toward the latent image carrier, and for a non-image portion, an electric field is generated for the toner toward the toner conveying member. This ensures that the toner adheres to the image portion of the latent image, and the toner traveling toward the non-image portion is pushed back to the toner transport member side, so that the toner hopped from the toner transport member is used efficiently for development. Therefore, scattering can be prevented, and high-quality development by low voltage driving can be realized.

  In this case, by setting the average value (average value potential) of the potential applied to the electrode of the toner conveying member to a potential between the potential of the latent image carrier image portion and the non-image portion potential, As described above, it is possible to generate an electric field in which the toner is directed toward the latent image carrier for the latent image portion of the latent image carrier and the toner is directed toward the toner conveying member for the non-image portion. .

Next, the width (electrode width) L and the electrode interval R of the plurality of electrodes 102 and the surface protective layer 103 provided on the toner conveying member 1 for conveying and hopping the toner will be described.
The electrode width L and the electrode interval R in the toner conveying member 1 greatly affect toner conveying efficiency and hopping efficiency. That is, the toner between the electrodes moves to the adjacent electrode on the substrate surface by a substantially horizontal electric field. On the other hand, since the toner on the electrode is given an initial velocity having at least a component in the vertical direction, most of the toner flies away from the substrate surface.

  In particular, since the toner near the electrode end surface moves over the adjacent electrode, when the electrode width L is wide, the number of toners on the electrode increases, and the toner having a large moving distance increases. Conveyance efficiency increases. However, if the electrode width L is too wide, the electric field strength in the vicinity of the center of the electrode is lowered, so that the toner adheres to the electrode and the transport efficiency is lowered. As a result of intensive studies, the present inventors have found that there is an appropriate electrode width for efficiently conveying and hopping powder at a low voltage.

  The electrode interval R determines the electric field strength between the electrodes from the relationship between the distance and the applied voltage. The narrower the interval R, the stronger the electric field strength, and the easier the initial speed of conveyance and hopping. However, for toner that moves from electrode to electrode, the distance traveled once is shortened, and the movement efficiency cannot be increased unless the drive frequency is increased. In this regard, as a result of intensive studies, the present inventors have found that there is an appropriate electrode interval for efficiently conveying and hopping powder at a low voltage.

  Furthermore, it has also been found that the thickness of the surface protective layer covering the electrode surface also affects the electric field strength on the electrode surface, in particular, the influence of the vertical component on the electric field lines is large and determines the hopping efficiency.

  Therefore, by properly setting the relationship between the electrode width, the electrode interval, and the surface protective layer thickness of the toner conveying member, it is possible to solve the toner adsorption problem on the electrode surface and perform efficient movement at a low voltage. .

  More specifically, first, the electrode width L is a width dimension for carrying and hopping at least one toner when the electrode width L is set to one time the toner diameter (powder diameter). On the other hand, if it is narrower than this, the electric field acting on the toner is reduced, and the conveying force and the flying force are lowered, which is not sufficient for practical use.

  Further, as the electrode width L is increased, the electric field lines are inclined in the traveling direction (horizontal direction) particularly near the center of the upper surface of the electrode, a region having a weak vertical electric field is generated, and the hopping generation force is reduced. . When the electrode width L is too wide, in an extreme case, the image force according to the charged charge of the toner, the van der Waals force, the adsorbing force due to moisture, etc. may be superior, and toner deposition may occur.

  From the efficiency of conveyance and hopping, if the width is such that about 20 toners are placed on the electrode, adsorption is unlikely to occur, and the conveyance and hopping operations can be efficiently performed with a low voltage drive waveform of about 100V. If it is wider than that, a region where adsorption occurs partially occurs. For example, when the average particle diameter of the toner is 5 μm, it corresponds to a range of 5 to 100 μm.

  A more preferable range of the electrode width L is not less than 2 times and not more than 10 times the average particle diameter of the powder in order to drive the applied voltage by the drive waveform more efficiently with a low voltage of 100 V or less. By setting the electrode width L within this range, the decrease in electric field strength near the center of the electrode surface can be suppressed to 1/3 or less, and the decrease in hopping efficiency is 10% or less, resulting in a significant decrease in efficiency. Disappears. This corresponds to a range of 10 to 50 μm, for example, when the average particle diameter of the toner is 5 μm.

  More preferably, the electrode width L is in the range of 2 to 6 times the average particle size of the toner. This is, for example, a range corresponding to 10 to 30 μm when the average particle diameter of the toner is 5 μm. It has been found that efficiency within this range is very good.

  Here, as shown in FIG. 14, the width (electrode width) L of the electrode 12 (102 in FIGS. 2 to 6) on the toner conveying member 11 (1 in FIGS. 2 to 6) is 30 μm, the electrode interval R is 30 μm, The thickness of the electrode 12 is 5 μm, the thickness of the surface protective layer 13 (103 in FIGS. 2 to 6) is 0.1 μm, and +100 V and 0 V are applied to the two adjacent electrodes 12 respectively, and the electrode width L and the electrode spacing R are applied. The results of measuring the strengths of the carrier electric field TE and the hopping electric field HE are shown in FIGS.

  Each evaluation data is a result of actual measurement and evaluation by simulation and actual measurement, and behavior of particles by high-speed video. In FIG. 14, two electrodes 12 are shown for easy understanding of details, but actual simulations and experiments evaluate an area having a sufficient number of electrodes as described above. The toner T has a particle size of 8 μm and a charge amount of −20 μC / g.

  The electric field strengths shown in FIGS. 15 and 16 are values of representative points on the electrode surface. The representative point TEa of the carrier electric field TE is a point above the electrode end 5 μm shown in FIG. 14 and a representative point HEa of the hopping electric field HE. Is a point 5 μm above the center of the electrode shown in FIG. 14 and corresponds to a representative point having the strongest electric field acting on the toner in the X direction and Y direction, respectively.

  From these FIGS. 15 and 16, the electric field capable of imparting a force acting on toner conveyance and hopping is (5E + 5) V / m or more, and the preferred electric field without the problem of adsorption is (1E + 6) V / m or more. It can be seen that a more preferable electric field capable of imparting a sufficient force is in the range of (2E + 6) V / m or more.

  Regarding the electrode interval R, since the electric field strength in the transport direction decreases as the interval increases, the value corresponding to the range of the electric field strength is the same, and as described above, the average particle size of the toner is 1 to 20 times or more. 2 times or less, preferably 2 times or more and 10 times or less, and more preferably 2 times or more and 6 times or less.

  Also, from FIG. 16, the hopping efficiency decreases as the electrode spacing R increases, but practical hopping efficiency can be obtained up to 20 times the average toner particle diameter. If the average particle diameter of the toner exceeds 20 times, the adsorbing force of a large amount of toner cannot be ignored, and a toner with no hopping is generated. In this respect, the electrode interval R is 20 times or less of the average particle diameter of the toner. There is a need to.

  As described above, the electric field strength in the Y direction is determined by the electrode width L and the electrode interval R, and the narrower the electric field strength is. Further, the electric field strength in the X direction near the end of the electrode is also determined by the electrode interval R, and the narrower the electric field strength is.

  Thus, the width of the electrode in the toner traveling direction is 1 to 20 times the average particle diameter of the toner, and the interval of the electrode in the toner traveling direction is 1 to 20 times the average particle diameter of the powder. As a result, the electrostatic force sufficient to convey and hop the toner acts on the charged toner on or between the electrodes, overcoming its mirror image force, van der Waals force, and other attractive forces. In addition, the toner can be prevented from staying and can be stably and efficiently conveyed and hopped at a low voltage.

  According to the studies by the present inventors, when the average particle diameter of the toner is 2 to 10 μm and Q / m is negatively charged, it is −3 to −40 μC / g, more preferably −10 to −30 μC / g. In the case of positive charging, when +3 to +40 μC / g, more preferably +10 to +30 μC / g, in particular, the above-described electrode configuration can be efficiently conveyed and hopped.

Next, the surface protective layer 103 (FIGS. 2 to 6) will be described.
By providing a surface protective layer, there is no contamination of the electrodes, adhesion of fine particles, etc., the surface can be maintained under conditions suitable for conveyance, creeping leaks in high humidity environments can be avoided, and Q / m fluctuations can be achieved. In addition, the charged charge amount of the powder can be stably maintained.

  Here, FIG. 17 shows the result of calculating the electric field strength in the X direction with the calculated value when the thickness of the surface protective layer 13 is changed in the range of 0.1 to 80 μm in the configuration of FIG.

  The dielectric constant ε of the surface protective layers 103 and 13 is higher than that of air, and usually ε = 2 or more. As can be seen from FIG. 14, when the film thickness of the surface protective layer (thickness from the electrode surface) is too thick, the electric field strength acting on the toner on the surface decreases. Therefore, considering the transport efficiency, temperature and humidity resistance environment, etc., the surface protective layer thickness that can be practically used without causing a decrease in efficiency for the transport operation is 10 μm or less, more preferably the efficiency is decreased. Is 5 μm or less, which is suppressed to several percent.

  Examples of the electric field strength acting on the electrode surface hopping are shown in FIGS. 18 shows an example in which the thickness of the surface protective layer is 5 μm, and FIG. 19 shows an example in which the thickness of the surface protective layer is 30 μm. In both cases, the applied voltage is 0 V and 100 V with an electrode width of 30 μm and an electrode interval of 30 μm.

  As can be seen from each of these figures, as the thickness of the surface protective layer increases, the electric field from the protective layer having a dielectric constant higher than that of air to the adjacent electrode increases, so that the vertical component of the surface decreases and the protective layer is protected. The electric field strength acting on the toner on the surface is reduced by the thickness of the layer.

That is, the vertical component electric field lines acting on hopping greatly depend on the protective layer thickness. An electric field that can efficiently apply a force that acts on hopping at a low voltage of about 100 V is (1E + 6) V / m or more as a preferable electric field that does not have a problem of adsorption, and a more preferable electric field that can apply a sufficient force is (2E + 6) ) V / m or more, and the protective layer thickness for that is 10 μm or less, more preferably 5 μm or less.
As a material for the surface protective layer, a material having a specific resistance of 10E6 Ωcm or more and a dielectric constant ε of 2 or more is preferably used.

  Thus, by providing a surface protective layer covering the electrode surface and setting the thickness of the surface protective layer to 10 μm or less, the electric field of the vertical component can be made to act more strongly on the toner, and hopping Efficiency can be increased.

  Regarding the relationship with the charging potential of the latent image carrier, when the toner is a negatively charged toner, the surface charging potential of the latent image carrier is −300 V or less, and when the toner is a positively charged toner, Set the charging potential to + 300V or less. That is, the charged potential on the surface of the latent image carrier is set to | 300 | V or less.

  As a result, as described above, when the electrodes are fine pitched, the generated electric field has a very large value even when the voltage applied between the electrodes 102 and 102 is a low voltage of 150 to 100 V or less. The toner adhering to the surface can be easily peeled off, flying and hopping. Further, ozone or NOx generated when charging a photoconductor such as OPC is very little or can be eliminated, which is very advantageous for environmental problems and durability of the photoconductor.

  Next, the relationship between the charged polarity of the toner to be moved and the material of the outermost layer of the surface protective layer will be described. The outermost layer of the surface protective layer refers to a layer that forms a surface in contact with the toner when the surface protective layer is a single layer, and when the surface protective layer is formed of a plurality of layers.

When conveying toner used in an image forming apparatus, the resin material occupying 80% or more of the toner is considered to have melting temperature, transparency in color, etc., and is generally a styrene-acrylic copolymer, Polyester resin, epoxy resin, polyol resin and the like are used.
Although the charging characteristics of the toner are affected by these resins, a charge control agent is added for the purpose of positively controlling the charge amount. As a charge control agent for black toner (BK), for example, nigrosine dyes and quaternary ammonium salts are used in the case of positive charge, and in the case of negative charge, for example, an azo metal-containing complex or a salicylic acid metal complex is used. The As the charge control agent for color toners, for example, quaternary ammonium salts and imidazole complexes are used in the case of positive charge, and in the case of negative charge, for example, salicylic acid metal complexes, salts, and organic boron salts are used. The

  On the other hand, these toners are repeatedly contacted and peeled off from the surface protective layer by an operation of conveying or hopping the toner conveying member by a phase-shift electric field (traveling wave electric field). However, the charge amount and polarity are determined by the charge series between materials.

  In this case, it is possible to improve the efficiency for conveyance, hopping, and photoconductor development by maintaining the toner charge amount to a saturation charge amount determined mainly by the charge control agent, or to some extent.

  Therefore, when the toner charging polarity is negative, at least the material of the layer that forms the outermost surface of the surface protective layer, the vicinity of the material used as the toner charge control agent on the triboelectric charging series (the region of conveyance and hopping is It is preferable to use a material located on the right end side or a material located on the positive end side. For example, when the charge control agent is a salicylic acid metal complex, a polyamide system located in the vicinity thereof is preferable. For example, polyamide (nylon: trade name) 66, nylon (trade name) 11 or the like is used.

  Further, when the toner charging polarity is positive, at least as the material of the layer that forms the outermost surface of the surface protective layer, the vicinity of the material used as the toner charge control agent on the triboelectric charging series (the region of conveyance and hopping is It is preferable to use a material located on the negative end side or a material located on the negative end side. For example, when the charge control agent is a quaternary ammonium salt, the vicinity thereof or a Teflon (registered trademark) material such as fluorine is used.

Next, the thickness of the electrode 102 will be described.
As described above, when a surface protective layer having a thickness of several μm is formed so as to cover the electrode surface, unevenness is generated on the surface of the toner conveying member corresponding to the region where the electrode is present and the region where the electrode is not present under the surface protective layer. Become. At this time, by forming the electrode in a thin layer having a thickness of 3 μm or less, it is possible to smoothly convey a powder of about 5 μm, such as toner, without causing a problem of unevenness on the surface of the protective film. Therefore, if the electrode is formed to a thickness of 3 μm or less, a toner transport member having a thin surface protective layer can be put into practical use without the need for a flattening process on the surface of the toner transport member, and an electric field for transport and hopping The strength is not reduced, and more efficient conveyance and hopping can be performed.

According to the method of developing the latent image on the latent image carrier using the developing device of the present invention, the toner can be stably supplied and the toner scattering can be reduced. Development quality is improved. That is, since the toner conveying member is rotated in the same direction as the toner conveying direction, the toner can be sufficiently supplied even at a high speed. Further, since the toner is pulled back in the area after passing through the development area, good development can be performed without any background contamination.
Further, if the image forming method using the above developing method is used, high-quality development can be performed with high development efficiency, and a high-quality image can be formed even at high speed. That is, toner scattering can be more reliably suppressed, and environmental problems can be avoided by low voltage driving.

Hereinafter, an image forming apparatus, a process cartridge, and the like having the developing device of the present invention will be described.
First, a first embodiment of an image forming apparatus according to the present invention including a developing device according to the present invention will be described with reference to FIG.
The overall outline and operation of the image forming apparatus will be described. A photosensitive drum 301 as a latent image carrier is formed with at least a photosensitive layer 303 on a substrate 302, and is driven to rotate in the direction indicated by an arrow in FIG. The The photosensitive drum 301 is uniformly charged by the charging device 305, and an electrostatic latent image is formed on the surface of the photosensitive drum 301 by writing with a laser beam corresponding to an image read from the exposure unit 306.

  Then, the electrostatic latent image on the surface of the photosensitive drum 301 is visualized by being attached with toner by the developing device 316 according to the present invention, and the visible image is transferred from the paper feed cassette 317. The transfer paper 319 transferred to the paper (recording medium) 319 by the transfer roller 320 to which the voltage from the transfer power source 321 is applied and the visible image transferred thereon is separated from the surface of the photosensitive drum 301, and then the fixing unit. The visible image is fixed through the rollers 323 and discharged to a discharge tray outside the apparatus.

  On the other hand, the toner remaining on the surface of the photosensitive drum 301 after the transfer is removed by the cleaning device 325, and the charge remaining on the surface of the photosensitive drum 301 is erased by the charge eliminating lamp 326.

  The developing device 316 is the same as the developing device of FIG. The configuration of the toner transport member 341 is the same as that of the toner transport member 1, and the configuration of a drive circuit that applies a drive waveform to each electrode of the toner transport member 341 is not shown, but in each embodiment of the developing device. The same as described.

Next, a second embodiment of the image forming apparatus according to the present invention will be described with reference to FIG. FIG. 2 is an overall schematic configuration diagram of the image forming apparatus.
The overall outline and operation of this image forming apparatus will be described. A photosensitive drum 401 (for example, an organic photosensitive member: OPC), which is a latent image carrier, is driven to rotate clockwise in FIG. When a document is placed on the contact glass 402 and a print start switch (not shown) is pressed, a scanning optical system 405 including a document illumination light source 403 and a mirror 404 and a scanning optical system 408 including mirrors 406 and 407 move. The original image is read.

  Here, the scanned document image is read as an image signal by the image reading element 410 disposed behind the lens 409, and the read image signal is digitized and subjected to image processing. Then, a laser diode (LD) is driven by the signal subjected to the image processing, and laser light from the laser diode is reflected by the polygon mirror 413 and then irradiated onto the photosensitive drum 401 via the mirror 414. The photosensitive drum 401 is uniformly charged by a charging device 415, and an electrostatic latent image is formed on the surface of the photosensitive drum 401 by writing with a laser beam.

  Then, the electrostatic latent image on the surface of the photosensitive drum 401 is visualized by being attached with toner by the developing device 416 according to the present invention, and the visible image (toner image) is supplied to the paper feeding unit 417A or 417B. To the transfer paper (recording medium) 419 fed from the feed roller 418A or 418B by the corona discharge of the transfer charger 420. The transfer sheet 419 to which the visible image is transferred is separated from the surface of the photosensitive drum 401 by the separation charger 421, conveyed by the conveyance belt 422, and passes through the pressure contact portion of the fixing roller pair 423 so that the visible image is transferred. The paper is fixed and discharged to a discharge tray 424 outside the apparatus.

  On the other hand, the toner remaining on the surface of the photosensitive drum 401 after the transfer is removed by the cleaning device 425, and the electric charge remaining on the surface of the photosensitive drum 401 is erased by the static elimination lamp 426.

  As shown in FIG. 22, the developing device 416 includes a developer accommodating portion 431 that accommodates the developer, an agitating / conveying screw 432 that agitates the toner in the developer accommodating portion 431, and a developing in the developer accommodating portion 431. A developer carrier 433 that uses a developer as a magnetic brush is provided with a developer layer regulating member 434 that regulates the amount of developer supplied, and a toner concentration sensor (not shown) that detects the permeability of the developer in the developer container. ) Is installed to detect the developer concentration. A toner replenishing port 435 is provided for replenishing toner to the developer accommodating portion when the toner concentration in the developer accommodating portion decreases.

In addition, a toner transport member 441 is provided for transporting and hopping the supplied toner for development and for collecting toner that has not been used for development in the developing device. The toner conveying member 441 is cylindrical and rotates in the same direction as the toner conveying direction by hopping.
As described in the first embodiment, the configuration of the toner transport member 441 is the same as that of the toner transport member 1, and the configuration of a drive circuit that applies a drive waveform to each electrode of the toner transport member 441 is not shown. However, it is the same as that described in each embodiment of the developing device.

  Next, a third embodiment of the image forming apparatus including the process cartridge according to the present invention will be briefly described with reference to FIGS. FIG. 23 is a schematic configuration diagram of the image forming apparatus, and FIG. 24 is a schematic configuration diagram of a process cartridge constituting the image forming apparatus.

  The image forming apparatus 500 is an example of a laser printer that forms a full color image with four colors of magenta (M), cyan (C), yellow (Y), and black (Bk), and corresponds to an image signal for each color. Four optical writing devices 501M, 501C, 501Y, and 501Bk (substantially 501B) (hereinafter also collectively referred to as “optical writing device 501”) that emit laser beams, and four process cartridges 502M, 502C, and 502Y for image formation 502 Bk (substantially 502 B), a paper feed cassette 503 that stores recording paper onto which an image is transferred, a paper feed roller 504 that feeds recording paper from the paper feed cassette 503, and a resist that conveys the recording paper at a predetermined timing A roller 505, a transfer belt 506 for conveying the recording paper to the transfer section of each process cartridge, and a recording paper A fixing device 509 comprising a fixing belt 507 and the pressing roller 508 to fix the photographed image, has a configuration including a discharge roller 510 or the like for discharging the discharge tray 511 recording paper after fixing.

  The four process cartridges 502M, 502C, 502Y, and 502B have the same configuration (hereinafter also collectively referred to as “process cartridge 502”). As shown in FIG. 24, each process cartridge 502 is an image carrier in the case. A drum-shaped photoconductor 521, a charging roller 522, a developing device 523 according to the present invention, a cleaning blade 524, and the like are integrally provided so as to be detachable from the image forming apparatus main body. By providing the developing device 523 in the detachable process cartridge 502, it is possible to improve maintenance and to easily replace the developing device 523 with another device.

  Further, in the developing device 523, a toner conveying member 1, a developer carrying member 528, and a stirring and conveying screw 529 are provided, and each color toner is stored. Further, a slit 530 is provided on the back side of the process cartridge 502 as a window through which the laser beam from the optical writing device 501 is incident.

  Each of the optical writing devices 501M, 501C, 501Y, and 501B includes a semiconductor laser, a collimator lens, an optical deflector such as a polygon mirror, a scanning imaging optical system, and the like. ), A laser beam modulated according to the image data for each color is input, and the photosensitive member 521 of each process cartridge 502M, 502C, 502Y, 502B is scanned, and an electrostatic charge image (electrostatic latent image). Write.

  When image formation is started, the photosensitive members 521 of the process cartridges 502M, 502C, 502Y, and 502B are uniformly charged by the charging roller 522, and according to the image data from the optical writing devices 501M, 501C, 501Y, and 501B. The laser beam is irradiated to form an electrostatic latent image of each color on each photoconductor.

  The electrostatic latent image formed on the photosensitive member 521 is developed with each color toner and visualized by EH development by the toner conveying member 1 of the developing device 523. In addition, the toner that has not been developed is transported by the toner transport member 1 and returned to the toner container 529 by the developer carrier 528. In this way, by performing development with the developing device according to the present invention, a high-quality image can be formed as described above.

  On the other hand, in synchronization with the image formation of each color of the process cartridges 502B, 502Y, 502C, and 502M, the recording paper in the supply cassette 503 is fed by the supply roller 504, and is applied to the transfer belt 506 by the registration roller 505 at a predetermined timing. It is conveyed toward. The recording paper is carried on the transfer belt 506 and sequentially conveyed toward the photosensitive members 521 of the four process cartridges 502B, 502Y, 502C, and 502M, and toners of Bk, Y, C, and M colors on the photosensitive members. Images are transferred one after the other. The recording sheet on which the four color toner images are transferred is conveyed to the fixing device 509, where the color image composed of the four color toner images is fixed, and is discharged onto the discharge tray 511.

  Next, a fourth embodiment of the image forming apparatus according to the present invention including the process cartridge according to the present invention will be briefly described with reference to FIGS. 25 is a schematic configuration diagram of the image forming apparatus, and FIG. 26 is a schematic configuration diagram of a process cartridge constituting the image forming apparatus.

  In this image forming apparatus, process cartridges 560Y, 560M, 560C, and 560B (hereinafter also collectively referred to as “process cartridges 560”) of respective colors are juxtaposed along a transfer belt (image carrier) 551 that extends horizontally. This is a tandem color image forming apparatus. The process cartridges 560 have been described in the order of yellow, magenta, cyan, and black, but are not specified in this order, and may be arranged in any order.

  The process cartridge 560 includes a latent image carrier 561, a charging unit 562, a developing unit 563 including the toner conveying member 1 according to the present invention, a cleaning device 564, and the like as a process cartridge. The process cartridge is configured so as to be integrally connected, and is configured to be detachable from a main body of an image forming apparatus such as a copying machine or a printer. Reference numeral 565 indicates an agitating and conveying screw, and reference numeral 566 indicates a developer carrier.

  As shown in FIG. 26, the developing unit 563 has the same basic structure as the developing device shown in the first embodiment, but transports and hops the supplied toner for development and is used for development. The toner conveying member for collecting the toner that has not been collected to the developing means is belt-like and rotates in the same direction as the toner conveying direction by hopping.

  Usually, since a color image forming apparatus has a plurality of image forming units, the apparatus becomes large. Further, when each unit such as the developing device, cleaning, charging, etc. fails individually or it is time to replace it due to its life, the apparatus is complicated and it takes much time to replace the unit.

  Therefore, a compact and highly durable color image forming apparatus that can be replaced by the user is provided by integrally connecting at least the components of the latent image carrier 561 and the developing means 563 as a process cartridge 560. be able to.

  Here, the developing toner on the image carrier 262 developed by the process cartridges 560Y, 560M, 560C, and 560B for each color is sequentially transferred to a transfer belt 551 to which a transfer voltage that extends horizontally is applied.

  In this way, yellow, magenta, cyan, and black images are formed, transferred onto the transfer belt 551 in a multiple manner, and transferred onto the transfer material 553 by the transfer unit 552. The multiple toner images on the transfer material 553 are fixed by a fixing device (not shown).

  Since each of the image forming apparatuses described in the above embodiments includes the developing means (apparatus) including the electrostatic transport apparatus according to the present invention, the apparatus can be reduced in size and cost, toner scattering, etc. Therefore, the image quality can be improved.

1 is a schematic configuration diagram illustrating a first embodiment of a developing device according to the present invention. FIG. 2 is a plan development view for explaining the configuration of the toner conveying member in FIG. 1. It is sectional drawing which follows the AA line of FIG. It is sectional drawing which follows the BB line of FIG. It is sectional drawing which follows the CC line of FIG. It is sectional drawing which follows the DD line | wire of FIG. It is a schematic diagram explaining an example of the drive waveform given to the conveyance board | substrate in this invention. FIG. 4 is a conceptual diagram for explaining toner conveyance and hopping in the present invention. FIG. 3 is a conceptual diagram for specifically explaining toner conveyance and hopping in the present invention. FIG. 2 is a block diagram illustrating an example of a drive circuit in FIG. 1. It is a schematic diagram explaining an example of the drive waveform (carrier voltage and collection | recovery carrier voltage pattern) formed by the drive circuit. 6 is a schematic diagram illustrating an example of a drive waveform (hopping voltage pattern) formed by the drive circuit 2. FIG. FIG. 6 is a schematic diagram for explaining another example of a drive waveform (hopping voltage pattern) formed by the drive circuit 2; FIG. 6 is a schematic diagram for explaining appropriate conditions for the electrode width and electrode interval of the toner conveying member in the present invention. In FIG. 14, it is a graph which shows the relationship between an electrode width and the electric field (X direction) of a 0V electrode end. In FIG. 14, it is a graph which shows the relationship between an electrode width and the electric field (Y direction) of a 0V electrode end. It is a graph which shows the relationship between the film thickness of a surface protective layer, and electric field strength in FIG. It is the schematic diagram which showed the strength of the electrolytic strength which acts on the hopping of the electrode surface in FIG. 14 with the relationship with the film thickness (5 micrometers) of the surface protective layer. It is the schematic diagram which showed the strength of the electrolytic strength which acts on the hopping of the electrode surface in FIG. 14 with the film thickness (30 micrometers) of the surface protective layer. 1 is a schematic configuration diagram illustrating a first embodiment of an image forming apparatus according to the present invention. It is a schematic block diagram explaining 2nd Embodiment of the image forming apparatus which concerns on this invention. FIG. 22 is a partially enlarged view for explaining a developing device in the image forming apparatus of FIG. 21. It is a schematic block diagram explaining 3rd Embodiment of the image forming apparatus which concerns on this invention. FIG. 24 is a schematic configuration diagram for explaining a process cartridge in the image forming apparatus of FIG. 23. It is a schematic block diagram explaining 4th Embodiment of the image forming apparatus which concerns on this invention. FIG. 24 is a schematic configuration diagram for explaining a process cartridge in the image forming apparatus of FIG. 23.

Explanation of symbols

1, 341, 441 Toner conveying member 2 Drive circuit 10, 301, 401, 521, 561, 565 Latent image carrier (photosensitive drum, photosensitive member)
DESCRIPTION OF SYMBOLS 11 Conveying area 12 Developing area 13 Collecting area 20, 433, 528 Developer carrier 22a-22c, 23a-23c Waveform amplifier 24, 431 Developer container 25A, 25B, 432, 529 Stirring conveying screw 26, 435 Toner supply port 27, 434 Developer layer regulating member 31 First voltage applying means 32 Second voltage applying means 101 Support substrate 102 Electrodes 316, 416, 523, 563 Developing device (developing means)

Claims (12)

A developer carrying member that holds the developer on the surface and forms a magnetic brush and conveys it, and a toner carrying member that conveys toner supplied from the developer carrying member to a position facing the latent image carrying member. In the developing device,
The developer carrying member is disposed to face the toner conveying member, and has a first voltage applying means for applying a voltage to the developer carrying member,
The toner transport member has a plurality of electrodes for forming a transport electric field, and is disposed to face the developer carrier and the latent image carrier, respectively, and applies a voltage to the toner transport member and the electrodes of the toner transport member. A developing device having a second voltage applying means for applying, wherein the toner conveying member is cylindrical or belt-like and is configured to rotate in the same direction as the toner conveying direction.   The developing device according to claim 1, wherein the developer is a two-component developer including a magnetic carrier and a nonmagnetic toner.   3. The magnetic brush formed of the developer held on the surface of the developer carrying member is in contact with the toner carrying member at a position where the developer carrying member and the toner carrying member face each other. The developing device according to 1.   At the position where the developer carrying member and the toner carrying member face each other, the toner carrying direction that is the same as the rotation direction of the toner carrying member is opposite to the developer feeding direction by the developer carrying member. The developing device according to claim 1, wherein the developing device is provided.   The voltage applied to the developer carrying member by the first voltage applying means is the magnitude of the electric field determined by the ratio between the potential difference and the distance between the developer carrying member and the toner conveying member, and the second voltage applying means uses the toner. 5. The developing according to claim 1, wherein the voltage is smaller than the electric field determined by the ratio of the voltage applied to the conveying member and the distance between the electrodes of the toner conveying member. apparatus.   The developing device according to claim 5, wherein the voltage applied to the developer carrying member by the first voltage applying unit is a voltage in which an AC voltage is superimposed on a DC voltage.   The developing device according to claim 6, wherein the AC component of the voltage applied to the developer carrying member by the first voltage applying unit is a rectangular wave.   An image forming apparatus comprising the developing device according to claim 1. A developer carrying member that holds the developer on the surface and forms and conveys a magnetic brush; and a toner carrying member that conveys toner supplied from the developer carrying member to a position facing the latent image carrying member;
The developer carrying member is disposed to face the toner carrying member, and has first voltage applying means for applying a voltage to the developer carrying member, and the toner carrying member has a plurality of members for forming a transport electric field. And a second voltage applying means for applying a voltage to the electrode of the toner carrying member and the toner carrying member, and the toner carrying member and the latent image carrying body. The development is characterized in that the conveying member is cylindrical or belt-like and is developed by attaching toner to the latent image on the latent image carrier by a developing device configured to rotate in the same direction as the toner conveying direction. Method.   An image forming method using the developing method according to claim 9.   A process cartridge comprising: at least one of a latent image carrier, a charging unit, and a cleaning unit in an electrophotographic process, and the developing device according to claim 1 integrally held therein. An image forming apparatus comprising the process cartridge according to claim 11.

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