JP2007316197A - Charger, process unit, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a charger for simply suppressing oxidation corrosion of a control electrode and a stable plate case over a long period, and to provide a process unit for excellently carrying out a process for image formation found by providing the charger over a long period of time, and an image forming apparatus for forming excellent images by providing the charger. <P>SOLUTION: The charger has the stable plate case 22 having a discharging opening part 220, and the control electrode 23 stretched in a case opening part 220 and facing a discharge member 21 arranged in the case 22. The charger has a corrosion suppression member 24 arranged along the discharge member 21 by being electrically connected to the case 22 and the control electrode 23, and a cleaning mechanism 25 of the corrosion suppression member 24. The process unit 9 including the charger 2 and the image forming apparatus A are composed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a charging device that can be used to charge an electrostatic latent image carrier such as a photosensitive member in an electrophotographic image forming apparatus. The present invention also relates to a process unit for image formation including an electrostatic latent image carrier and a charging device for charging the electrostatic latent image carrier, and also relates to an image forming apparatus.

  A typical charging device that can be used to charge an electrostatic latent image carrier such as a photoreceptor in an electrophotographic image forming apparatus is a corona charging type charging apparatus.

  Corona charging type charging devices are generally divided into corotron type (type without control electrode) and scorotron type (type using control electrode) depending on whether or not a control electrode is provided. Is done.

  A scorotron charging device generally has a stabilizer case having a discharge opening, a discharge member disposed in the stabilizer case, and the discharge member, and is stretched over the discharge opening of the stabilizer case. Control electrode. The corotron charging device is generally obtained by removing the control electrode from the scorotron charging device.

  Since the scorotron charging device can control the inflow amount of corona ions generated by the discharge from the discharge member to the charged body (for example, the photosensitive body) by the control electrode set at a constant potential to be almost constant. Even if the voltage applied to the discharge member fluctuates, it is possible to suppress fluctuations in the charging potential to the object to be charged, and to suppress uneven charging of the object to be charged compared to a corotron charging device that does not have a control electrode. There are advantages that can be made. Accordingly, in order to charge an electrostatic latent image carrier such as a photoreceptor in an electrophotographic image forming apparatus, a scorotron charging device is widely used.

  As the discharge member in the charging device, a stretched wire has been used since it has been used. However, as a whole, a strip-like discharge member having a needle electrode portion connected in a sawtooth shape has been put into practical use. It is known that this type of discharge member generates less ozone than the wire type.

  There are various types of control electrodes in the scorotron charging device, such as a type in which a large number of slits are formed in a conductive plate, a type in which conductive wires are combined in a mesh shape, etc. Even so, a large number of openings are formed.

  As in the case of the corotron type charging device, in the scorotron type charging device, when a DC high voltage is applied to the discharge member to generate discharge, discharge products such as ozone and nitrogen oxide are generated. Among such discharge products, ozone gradually corrodes not only the discharge member but also the stabilizer plate case and the control electrode. Further, among the discharge products, nitrogen oxides and the like adhere not only to the discharge member but also to the stable plate case and the control electrode. As described above, the discharge member, the stabilizer case, and the control electrode are gradually contaminated due to the discharge products while the charging device is used.

On the other hand, in an image forming apparatus such as an electrophotographic system, dust such as recording medium powder, electrostatic latent image developing process, toner transferred to an intermediate transfer member or recording medium, or toner scattered in a transfer process is recorded on the toner. Additives [eg, silica (SiO ₂ )], etc., are often floating, but they adhere to the discharge member of the charging device, the stabilizer case, and the control electrode mounted on the image forming apparatus. However, as the image forming apparatus is used repeatedly, it gradually accumulates and contaminates them.

  In particular, when the control electrode is contaminated in a scorotron charging device, for example, when the charging device is a charging device for a photosensitive member, the amount of inflow of corona ions into the photosensitive member by the control electrode is considered. The control becomes unstable and uneven charging occurs on the surface of the photoreceptor.

  In any case, if each part of the charging device is contaminated due to discharge products or due to scattered toner or the like, it becomes difficult to uniformly charge the surface of the object to be charged, resulting in uneven charging. Image noise will occur.

  In this regard, Japanese Patent Application Laid-Open No. 2001-154449 discloses that an auxiliary wire is positioned farther from a photosensitive member as a charged body than the discharge wire in order to prevent silica and toner from adhering to the discharge wire (original discharge wire). Contamination of the discharge wire in such a way that a current larger than the current flowing through the discharge wire is passed through the auxiliary wire, thereby preferentially adhering suspended matter such as toner or silica to the auxiliary wire. It is described that suppresses.

  Japanese Patent Laid-Open No. 2000-356892 discloses that a photocatalytic substance capable of decomposing discharge products such as ozone and nitrogen oxide is applied to a constituent member of a charging device, for example, a stabilizing plate case, and the photocatalyst is discharged during discharge. It is described that a discharge product is decomposed by irradiating a substance with light having a wavelength component that excites it.

  Japanese Patent Application Laid-Open No. 7-287436 discloses that in a charging device provided with a cleaning mechanism for cleaning a discharge wire, discharge products such as ozone and floating matter such as scattered toner adhere to the discharge wire and the cleaning mechanism. In order to suppress this, it is described that a mechanism for supplying external normal air to the discharge wire extending portion without being mixed with air in the dirty charging device is described.

JP 2001-154449 A JP 2000-356892 A JP-A-7-287436

  However, as described in Japanese Patent Laid-Open No. 2001-154449, the auxiliary wire is stretched behind the discharge wire, and a current larger than the discharge wire is passed through the auxiliary wire, so that the toner is preferentially applied to the auxiliary wire. In the method of attaching floating substances such as silica and silica, it is difficult to expect the effect of preventing corrosion of the charging device constituent member by ozone, which is a discharge product.

  As described in Japanese Patent Application Laid-Open No. 2000-356892, a photocatalytic substance capable of decomposing ozone and nitrogen oxides is applied to a constituent member of a charging device, and light that excites the photocatalytic substance is discharged during discharge. In the method, it is difficult to suppress corrosion of the charging device constituent member due to ozone or the like for a long time.

  As described in JP-A-7-287436, there is provided a mechanism for supplying normal external air to the discharge wire extending portion without mixing with dirty air in the charging device having a discharge wire cleaning mechanism. In the method of providing, it is necessary to provide a clean air supply mechanism, which complicates the configuration of the charging device or a part associated therewith.

  Thus, with the conventional technology, it is difficult to easily suppress long-term contamination of the charging device constituent members. In particular, it is difficult to easily suppress the oxidative corrosion of the charging device constituent members due to ozone or the like in the long term. It has been proposed that a discharge member having a relatively small proportion of the charging device constituent members is appropriately cleaned by providing a discharge member cleaning mechanism as described in JP-A-7-287436. The control electrode and the stabilization plate case occupy a larger proportion than the discharge member. For example, if the cleaning mechanism is provided, the configuration of the charging device becomes complicated and expensive. Moreover, even if a cleaning mechanism is provided, it is difficult to remove and remove the oxidized corrosion. In particular, contamination of the control electrode tends to cause uneven charging of the charged body as described above.

  Accordingly, the present invention provides a stabilizer case having an opening for discharge, a discharge member disposed in the stabilizer plate case, and a control electrode extending to the discharge opening of the stabilizer case facing the discharge member. It is a first aspect of the present invention to provide a charging device that can easily suppress long-term oxidation corrosion of the control electrode and the stabilizer plate case, and can charge the object to be charged satisfactorily for a long time. It is an issue.

  The present invention also provides an image forming method in which an electrostatic latent image is formed on an electrostatic latent image bearing member, the electrostatic latent image is developed to form a visible toner image, and the toner image is transferred to a transfer target. A process unit comprising a charging unit for charging the electrostatic latent image carrier and the surface of the electrostatic latent image carrier prior to the formation of the electrostatic latent image as a process unit for the apparatus, It is a second object to provide a process unit that can satisfactorily carry out the process for image formation required for the long term.

  The present invention further forms an electrostatic latent image on an electrostatic latent image carrier, develops the electrostatic latent image to form a visible toner image, and transfers the toner image to a transfer object. A third object is to provide an image forming apparatus that can form a good image over a long period of time.

In order to solve the first problem, the present invention provides:
A charging device having a stable plate case having a discharge opening, a discharge member disposed in the stable plate case, and a control electrode facing the discharge member and stretched in the discharge opening of the stable plate case The stable plate case material and the control electrode material are formed of a material that is more susceptible to oxidative corrosion than the stable plate case material and the control electrode material when electrically connected to the control electrode material. A corrosion inhibiting member for suppressing oxidative corrosion of the stabilizing plate case and the control electrode, which is electrically connected to the control electrode and disposed in the stabilizing plate case along the discharge member, and the corrosion inhibition A charging device having a member cleaning mechanism is provided.

In order to solve the second problem, the present invention provides:
Process unit for an image forming apparatus that forms an electrostatic latent image on an electrostatic latent image carrier, develops the electrostatic latent image to form a visible toner image, and transfers the toner image to a transfer target A process for charging the surface of the latent electrostatic image bearing member and the surface of the latent electrostatic image bearing member prior to the formation of the latent electrostatic image, and comprising the charging device according to the present invention as the charging device. Provide unit.

In order to solve the third problem, the present invention
An image forming apparatus that forms an electrostatic latent image on an electrostatic latent image carrier, develops the electrostatic latent image to form a visible toner image, and transfers the toner image to a transfer target. One or more charging devices including a charging device that charges the surface of the electrostatic latent image carrier prior to the formation of the electrostatic latent image are provided. At least one of the charging devices is a charging device according to the present invention. An image forming apparatus is provided.

  According to the charging device of the present invention, the corrosion inhibiting member is disposed along the discharge member in the stabilizer case. The corrosion inhibiting member is formed of a material that is more easily oxidized and corroded than the stabilizing plate case material and the control electrode material when electrically connected to the stabilizing plate case material and the control electrode material. When the current flows through the stabilizer case, the control electrode, and the corrosion inhibiting member electrically connected to the charging device during the operation of the charging device, it is generated by the discharge from the discharge member. Oxidative corrosion due to ozone or the like proceeds more preferentially in the corrosion suppression member than the stabilizing plate case and the control electrode, and the corrosion suppression member thus corroded can be preferentially continued by being cleaned appropriately by its cleaning mechanism. The corrosion of the stabilizer case and the control electrode can be suppressed accordingly.

  Thus, when the cleaning mechanism is provided due to the large proportion of the discharge member compared to the discharge member, etc., the charging electrode configuration becomes complicated, and the oxidative corrosion can be easily suppressed in the long term for the control electrode and the stabilizer plate case, which are expensive, Accordingly, the object to be charged can be charged well over a long period of time.

When different metals are electrically connected, a metal having a large ionization tendency serves as an anode and a metal having a small ionization tendency serves as a cathode, and current flows, and the metal serving as an anode is oxidatively corroded.
Therefore, as the corrosion inhibiting member, a member made of a metal material having a greater tendency to ionize than any of the stabilizer case material and the control electrode material can be given as a representative example.

  For example, the stabilizer case and the control electrode are often made of chromium (Cr) stainless steel or nickel-chromium (Ni-Cr) stainless steel, but the stabilizer case and control electrode are made of such materials. Examples of the material for the corrosion-inhibiting member when it is formed of zinc, aluminum, and magnesium, which have a higher ionization tendency than iron, chromium, and nickel.

  The charging device according to the present invention may include a cleaning mechanism including a discharge member cleaning member for cleaning the discharge member. In that case, the said corrosion suppression member may serve as the guide member for moving this cleaning member for discharge members along this discharge member.

  According to the process unit according to the present invention, the charging device mounted on the process unit is the charging device according to the present invention, and the corrosion of the control electrode and the stabilizer plate case can be suppressed over a long period of time. The surface can be charged to a desired state, and when viewed as a whole process unit, the process for image formation required for it can be carried out satisfactorily over a long period of time.

  The process unit according to the present invention includes a developing device that develops an electrostatic latent image formed on an electrostatic latent image carrier to form a visible toner image, and toner that remains on the electrostatic latent image carrier after toner image transfer. A cleaning device that removes and the like may be provided.

The process unit according to the present invention may be for a monochrome image forming apparatus or a color image forming apparatus.
The process unit according to the present invention may be detachable from the image forming apparatus main body.

  According to the image forming apparatus according to the present invention, at least one of the charging devices is the charging device according to the present invention, and the charging device can suppress corrosion of the control electrode and the stabilizer case over a long period of time. The surface of the latent electrostatic image bearing member can be charged to a desired state for a long period of time, and a good image can be formed for a long period of time as the entire image forming apparatus.

  The image forming apparatus according to the present invention may be a monochrome image forming apparatus or a color image forming apparatus. The image forming apparatus according to the present invention may employ the process unit according to the present invention.

The image forming apparatus according to the present invention includes: “forming an electrostatic latent image on an electrostatic latent image carrier, developing the electrostatic latent image to form a visible toner image, and applying the toner image to a transfer object; An image forming apparatus to be transferred ".
Here, the “transfer object” is a recording medium such as normal recording paper in a monochrome image forming apparatus, and the toner image transferred to the recording medium is fixed to the recording medium.
In the color image forming apparatus, the “transfer object” is generally an intermediate transfer member such as an intermediate transfer belt, and the toner image primarily transferred to the intermediate transfer member is further transferred to the recording medium as a secondary transfer. And fixed.
In a color image forming apparatus, an image in which a toner image formed on an electrostatic latent image carrier such as a photoconductor is transferred to a recording medium electrostatically supported on a charged recording medium support. There is also a forming device. In this case, the “transfer object” is the recording medium.

  Specific examples of the image forming apparatus according to the present invention include a stand-alone or network-connected copying machine, a printer, a facsimile machine, and a multifunction machine that combines two or more of these.

  As described above, according to the present invention, the stabilizing plate case having the discharge opening, the discharge member disposed in the stabilization plate case, and the discharge member, the tension plate is stretched over the discharge opening of the stabilization plate case. Provided is a charging device having a control electrode, which can easily suppress the oxidative corrosion of the control electrode and the stabilizer plate case over the long term, and can charge the object to be charged satisfactorily for a long time. can do.

  Further, according to the present invention, an image in which an electrostatic latent image is formed on an electrostatic latent image carrier, the electrostatic latent image is developed to form a visible toner image, and the toner image is transferred to a transfer target. A process unit for a forming apparatus, comprising: a charging device that charges the surface of the electrostatic latent image carrier and the surface of the electrostatic latent image carrier prior to the formation of the electrostatic latent image, By employing the charging device according to the present invention as the charging device, it is possible to provide a process unit that can satisfactorily perform the process for image formation required for the process unit over a long period of time.

  Further, according to the present invention, an electrostatic latent image is formed on an electrostatic latent image carrier, the latent electrostatic image is developed to form a visible toner image, and the toner image is transferred to a transfer target image. An image forming apparatus, and at least one of the one or more charging devices constituting the image forming apparatus is a charging apparatus according to the present invention, and thus forms a good image for a long period of time. An image forming apparatus that can be used can be provided.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows an example (printer) of an image forming apparatus provided with an example of a charging device (charging device 2) according to the present invention. FIG. 2 is a schematic cross-sectional view of the charging device 2 as viewed from the right side of FIG.

  The printer A in FIG. 1 is a printer that forms a monochrome image. The printer A includes an electrostatic latent image carrier 1, and a charging device 2, an image exposure device 3, a developing device 4, a transfer device 5, a cleaning device 6 and the like sequentially arranged around the electrostatic latent image carrier 1.

Here, the image carrier 1 is a drum-type negatively chargeable photoconductor.
The charging device 2 is a scorotron charging device that charges the surface of the photosensitive member 1 by corona discharge, which will be described in detail later.
In this example, the image exposure apparatus 3 performs exposure using a laser beam, and can perform image exposure on the photoreceptor 1 in accordance with image information provided from a personal computer (not shown).

  The developing device 4 is a developing device that reversely develops the electrostatic latent image on the photoreceptor 1 using negatively chargeable toner. Development of the electrostatic latent image on the photoreceptor 1 is performed by a developing roller 41 that carries toner and transports it to the developing area.

The transfer device 5 includes a transfer roller 51 in this example.
In this example, the cleaning device 6 has a cleaning blade 61 disposed in contact with the surface of the photoreceptor 1.

  The photoreceptor 1, the charging device 2, the developing device 4, and the cleaning device 6 are mounted in a cartridge case, and form a process unit 9 together with the case. The process unit 9 is detachable from the image forming apparatus main body.

  The image forming apparatus A is also provided with a storage cassette (not shown) for the recording medium S such as recording paper, and the recording medium S stored in the cassette is pulled out one by one by a medium supply roller (not shown). , And can be supplied to the timing roller pair 7.

  A fixing device 8 and a medium discharge roller and a medium discharge tray (not shown) are provided downstream of the transfer device 5 in the recording medium conveyance direction.

  As shown in FIG. 2, the charging device 2 includes a strip-shaped discharge member 21 extending in the same direction as the rotation axis of the photoreceptor 1 and a case 22 containing the discharge member. The case 22 has an opening 220 opened for discharge toward the photosensitive member 1, and a control electrode 23 is stretched over the opening. A corrosion inhibiting member 24 described later is also provided in the case 22. Further, the charging device 2 is also provided with a cleaning mechanism 25 for a corrosion inhibiting member.

  As shown in FIG. 2, the discharge member 21 is a strip-like member as a whole in which needle-like discharge electrodes 210 are connected in a sawtooth shape, and insulating support portions 211 and 212 provided in the case 22. Both end portions are supported by and extend in the longitudinal direction of the case 22.

  The case 22 is formed in a box shape that surrounds the discharge member 21 by bending a plate-like body that acts as a stabilizing plate that stabilizes the discharge from the discharge member 21, and the discharge opening as described above. 220. The opening 220 is directed to the photoreceptor 1.

  The control electrode 23 is an electrode for controlling the charging potential of the photosensitive member 1 as a member to be charged here to a predetermined potential, and is a rectangular plate-like electrode that extends long in the same direction as the discharge member 21 as a whole. Although not shown, in this example, a large number of slit openings are formed at substantially equal intervals in each of the lateral direction and the longitudinal direction of the electrode plate.

  The control electrode 23 is stretched over the opening 220 of the case with the one end 231 and the other end 232 in contact with the pair of height positioning portions 221 and 222 provided in the case 22. Has been. In this example, the control electrode 23 is electrically connected to the case 22.

  In this example, the discharge member 21 is made of stainless steel (SUS304), and the case 22 and the control electrode 23 are both made of nickel-chromium stainless steel.

  The corrosion suppressing member 24 may have a cross-sectional shape other than a circle such as a quadrangle or a triangle, but here is a rod-like member having a circular cross-section, and is opposite to the control electrode 23 with the discharge member 21 in between. Are arranged in parallel with the discharge member 21, and are supported by the case in a state where both ends are electrically connected to the case 22.

  The corrosion suppressing member 24 is a metal rod-like member, and here is formed of aluminum having a higher ionization tendency than any of iron, nickel, and chromium, which are constituent materials of the case 22 and the control electrode 23. The corrosion inhibiting member 24 may be formed of zinc, magnesium, or the like, which has a higher ionization tendency than iron, nickel, and chromium (see FIG. 4).

  The cleaning mechanism 25 includes a cleaning member 251 that can be rubbed and cleaned by contacting the rod-like corrosion suppressing member 24, a holder 252 of the cleaning member 251, and a support member 253 of the holder 252. The support member 253 extends through the hole h extending in the longitudinal direction of the case provided in the back wall of the case 22 and extends to the outside of the case, and is connected to the female screw member 254. The female screw member 254 is disposed in parallel with the corrosion suppressing member 24 and is screwed to a screw rod 255 that can rotate forward and backward by a driving unit (not shown) or manually by a user or a serviceman.

  The cleaning member 251 is preferably formed of a material having high strength and excellent wear resistance, and can be formed in a plate shape, a brush shape, a mesh shape or the like so as to cover the corrosion suppressing member 24. When forming in plate shape, mesh shape, etc., you may press-contact with the corrosion suppression member 24 with a spring as needed. In this example, a ceramic material having high strength and excellent wear resistance is used to form a brush shape covering the corrosion inhibiting member 24.

  The screw rod 255 is rotated to support the female screw member 254, and accordingly, the support member 253 and the holder 252 are moved to the right, left, or left and right in the drawing in parallel with the corrosion inhibiting member 24, thereby being supported by the holder 252. The cleaned cleaning member 251 is moved in the same direction, and the corrosion suppressing member 24 is rubbed, so that the corrosive substances, adhering toner and the like on the member can be removed and cleaned.

  According to the printer A described above, the photosensitive member 1 is rotationally driven in the clockwise direction CW in the drawing by a photosensitive member driving motor (not shown), and the surface thereof is respectively applied to the discharge member 21 and the control electrode 23 from the power supply device (not shown). Is charged to a predetermined potential by the charging device 2, and image exposure is performed on the charged region from the image exposure device 3 according to the image to be formed, thereby forming an electrostatic latent image. The This electrostatic latent image is developed by the developing roller 41 of the developing device 4 to be a visible toner image. At this time, a developing bias voltage is applied to the developing roller 41 from a power supply (not shown) and is driven to rotate by a developing motor (not shown).

  On the other hand, the recording medium S is pulled out from a cassette (not shown) by a medium supply roller and supplied to the timing roller pair 7. The rotation of the timing roller pair 7 is turned on and off by a clutch (not shown), and the recording medium S is supplied to the transfer region as the toner image on the photoreceptor 1 arrives at the transfer roller 51. Then, the toner image on the photosensitive member 1 is transferred to the recording medium S by the transfer roller 51 to which a transfer bias is applied from a transfer power supply (not shown), and then the recording medium S is passed through the fixing device 8 and the toner. The image is fixed under heat and pressure and discharged onto a tray (not shown). In this way, an image is formed.

  The toner remaining on the photoreceptor 1 by the toner image transfer is removed and cleaned by the cleaning device 6.

  The charging device 2 will be further described. A corrosion inhibiting member 24 is disposed along the discharge member 21 in the stabilizer case 22. The corrosion suppressing member 24 is formed of a material having a higher ionization tendency than the stabilizing plate case material and the control electrode material, and is electrically connected to the stabilizing plate case 22 and the control electrode 23. Accordingly, the current flows with the corrosion suppressing member 24 serving as the anode, the stabilizer case 22 and the control electrode 23 serving as the cathode, and the corrosion suppressing member 24 serving as the anode is preferentially due to ozone generated by the discharge from the discharge member 21. Further, the corrosion inhibiting member 24 thus corroded can be preferentially continued by being cleaned appropriately by the cleaning mechanism 25, so that the oxidative corrosion of the stabilizing plate case 22 and the control electrode 23 can be prevented. It is suppressed.

  Thus, the ratio of the charging member 21 is larger than that of the discharging member 21. If the cleaning mechanism is provided, the structure of the charging device becomes complicated, and the control electrode 23 and the stabilizing plate case 22 that are expensive are easily suppressed in a long term. Accordingly, the photosensitive member 1 can be charged satisfactorily in a state where inconveniences such as uneven charging are suppressed for a long time.

  Further, the process unit 9 including such a charging device includes the charging device 2 so that the process for image formation required for the process unit 9 can be satisfactorily performed over a long period of time. By using the charging device 2, a good image can be formed for a long time.

FIG. 3 shows another example of the charging device according to the present invention. The charging device 2 ′ shown in FIG. 3 is obtained by adding a cleaning mechanism for the discharge member 21 to the charging device 2 shown in FIGS.
The charging device 2 ′ is provided with a cleaning member 26 for rubbing and cleaning the discharge member 21, the cleaning member 26 is supported by the holder 261, and the holder 261 is a cleaning member holder in the cleaning mechanism 25 of the corrosion inhibiting member. 252.

  The rest of the configuration is the same as that of the charging device 2. In FIG. 3, the same reference numerals as those of the charging device 2 are assigned to the same components and parts as those of the charging device 2.

  According to the charging device 2 ′, the cleaning mechanism 25 of the corrosion suppressing member 24 also serves as a part of the cleaning mechanism of the discharge member 21, and the cleaning member 252 is moved along the member for cleaning the corrosion suppressing member 24. Then, the cleaning member 26 of the discharge member 21 also moves, and the discharge member 21 can be easily rubbed and cleaned. At this time, the corrosion suppressing member 24 also serves as a guide for moving the cleaning member 26 along the discharge member 21.

  According to the charging device 2 ′, the discharge member 21 can also be cleaned, so that the photosensitive member 1 can be satisfactorily charged over a longer period than the charging device 2. The process unit equipped with the charging device 2 ′ can exhibit the required performance for a longer period, and the image forming apparatus equipped with the charging device 2 ′ can form a good image for a longer period.

  The printer A described above is a monochrome image forming apparatus that transfers and fixes the toner image on the photoreceptor 1 to the recording medium S. However, the present invention is a monochrome image forming apparatus that employs an intermediate transfer body, a so-called four-cycle type, The present invention can also be applied to a color image forming apparatus such as a tandem type.

  The present invention relates to a stabilizer plate, a discharge member arranged in the stabilizer plate case, and a charging device having a control electrode stretched in a discharge opening of the stabilizer plate case, In addition, the present invention can be used to provide a charging device that can easily suppress oxidative corrosion of the control electrode over a long period of time, a process unit equipped with the charging device, and an image forming apparatus equipped with the charging device.

1 is a diagram schematically showing a configuration of an example of an image forming apparatus according to the present invention. It is a schematic sectional drawing of a charging device. It is a schematic sectional drawing of the other example of a charging device. It is a figure which shows the magnitude | size of the ionization tendency of a typical metal.

Explanation of symbols

A Image forming apparatus 1 Photoconductor 2, 2 ′ Charging device 21 Discharge member 22 Stabilizing plate case 220 Opening portion 23 of case 22 Control electrode 24 Corrosion suppressing member 25 Cleaning mechanism 251 for member 24 Cleaning member 252 Cleaning member holder 253 Holder support member 254 Female thread member 255 Screw rod 26 Cleaning member 261 of discharge member Holder of member 26

Claims (6)

A charging device having a stable plate case having a discharge opening, a discharge member disposed in the stable plate case, and a control electrode facing the discharge member and stretched in the discharge opening of the stable plate case The stable plate case material and the control electrode material are formed of a material that is more susceptible to oxidative corrosion than the stable plate case material and the control electrode material when electrically connected to the control electrode material. A corrosion inhibiting member for suppressing oxidative corrosion of the stabilizing plate case and the control electrode, which is electrically connected to the control electrode and disposed in the stabilizing plate case along the discharge member, and the corrosion inhibition A charging device having a member cleaning mechanism. The charging device according to claim 1, wherein the corrosion suppressing member is formed of a metal material having a greater tendency to ionize than any of the stabilizer plate case material and the control electrode material. A cleaning mechanism including a discharging member cleaning member for cleaning the discharging member is provided, and the corrosion suppressing member also serves as a guide member for moving the discharging member cleaning member along the discharging member. Item 3. The charging device according to Item 1 or 2. Process unit for an image forming apparatus that forms an electrostatic latent image on an electrostatic latent image carrier, develops the electrostatic latent image to form a visible toner image, and transfers the toner image to a transfer target A charging device for charging the electrostatic latent image carrier and the surface of the electrostatic latent image carrier prior to the formation of the electrostatic latent image, and the charging device according to claim 1, 2, or 3 as a charging device. Process unit with equipment. An image forming apparatus that forms an electrostatic latent image on an electrostatic latent image carrier, develops the electrostatic latent image to form a visible toner image, and transfers the toner image to a transfer target. One or two or more charging devices including a charging device that charges the surface of the electrostatic latent image carrier prior to the formation of the electrostatic latent image, and at least one of the charging devices includes: 4. An image forming apparatus, which is a charging device according to item 3. The image forming apparatus according to claim 5, wherein the process unit according to claim 4 is used.