JP2017083773A - Charger, image forming unit, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charger that can reduce time to clean a discharge electrode compared with a case where one cleaning member is moved to clean the entire range of a discharge electrode, and an image forming unit and an image forming apparatus including the same.SOLUTION: In a preliminary charger according to a comparison form, one cleaning member 120 is reciprocatingly moved along a discharge wire 308 to clean the discharge wire 108. Meanwhile, in a preliminary charger 58, two (a pair of) cleaning members 120 are reciprocatingly moved along a discharge wire 108 to clean the discharge wire 108. The use of the preliminary charger 58 thus reduces time to clean the discharge wire 108 compared with a case where a preliminary charger 300 is used.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a charger, an image forming unit, and an image forming apparatus.

  The corona discharger described in Patent Document 1 includes a discharge wire and a single cleaning member that moves in the longitudinal direction of the discharge wire while contacting the discharge wire and cleans the discharge wire.

  This cleaning member stands by at one end of the discharge wire (discharge electrode) during the printing operation, and reciprocates in the longitudinal direction of the discharge wire while being in contact with the discharge wire during cleaning.

JP 2006-308906 A

  The subject of this invention is shortening the time which cleans a discharge electrode compared with the case where one cleaning member is moved and the whole range of a discharge electrode is cleaned.

  According to a first aspect of the present invention, there is provided a charger that faces the outer peripheral surface of the rotating image carrier and extends in the axial direction of the image carrier, and is in contact with the discharge electrode and has a predetermined standby time. A plurality of cleaning members arranged at positions, and a moving member for separately moving the plurality of cleaning members arranged at standby positions along the discharge electrodes are provided.

  According to a second aspect of the present invention, there is provided a charger according to the first aspect, wherein a pair of the cleaning members are provided, and the pair of cleaning members at a standby position are arranged on a central side in the axial direction of the discharge electrode. The moving member moves the pair of cleaning members in the standby position in the axial direction so as to be separated from each other and then moves in the axial direction so as to approach each other. Features.

  An image forming unit according to claim 3 of the present invention is precharged by the rotating image carrier, the charger according to claim 1 or 2 that preliminarily charges the outer peripheral surface of the image carrier, and the charger. And a main charger that charges the outer peripheral surface of the image carrier to a potential within a predetermined range.

  An image forming apparatus according to a fourth aspect of the present invention irradiates the outer peripheral surface of the image forming unit according to the third aspect and the image carrier charged by the main charger with exposure light to form an electrostatic latent image. An exposure device to be formed, a developing device for developing an electrostatic latent image formed on the outer peripheral surface of the image carrier as a toner image, and a toner image formed on the outer peripheral surface of the image carrier to a recording medium And a transfer device.

  An image forming apparatus according to a fifth aspect of the present invention is precharged by the rotating image carrier, the charger according to claim 1 or 2 for precharging the outer peripheral surface of the image carrier, and the charger. A main charger that charges the outer peripheral surface of the image carrier to a potential within a predetermined range, and an electrostatic latent image is formed by irradiating the outer peripheral surface of the image carrier charged by the main charger with exposure light. An exposure device to be formed, a developing device for developing an electrostatic latent image formed on the outer peripheral surface of the image carrier as a toner image, and a toner image formed on the outer peripheral surface of the image carrier to a recording medium And a transfer device.

  According to the charger of the first aspect of the present invention, it is possible to shorten the time for cleaning the discharge electrode as compared with the case where one cleaning member is moved to clean the entire range of the discharge electrode.

  According to the charger of the second aspect of the present invention, the pair of cleaning members at the standby position is attached to the discharge electrode as compared with the case where the pair of cleaning members are disposed at both ends of the discharge electrode in the axial direction. The substance can be brought close to both end portions of the discharge electrode in the axial direction.

  According to the image forming unit of claim 3 of the present invention, the outer peripheral surface of the image carrier is determined in advance after cleaning of the discharge electrode is started, as compared with the case where the charger of claim 1 or 2 is not provided. The time required for charging to a potential within the specified range can be shortened.

  According to the image forming apparatus of the fourth aspect of the present invention, as compared with the case where the image forming unit according to the third aspect is not provided, the toner image is transferred to the recording medium after the cleaning of the discharge electrode is started. Can be shortened.

  According to the image forming apparatus of the fifth aspect of the present invention, as compared with the case where the charger of the first or second aspect is not provided, the toner image is transferred to the recording medium after the discharge electrode cleaning is started. The time can be shortened.

FIG. 2 is a front view showing a preliminary charger and an image forming unit according to an embodiment of the present invention. (A) (B) It is the front view which showed the preliminary charger which concerns on embodiment of this invention, and the image holding body. It is the perspective view which showed the preliminary charger which concerns on embodiment of this invention. It is sectional drawing which showed the preliminary charger which concerns on embodiment of this invention. 1 is a configuration diagram illustrating an image forming unit according to an embodiment of the present invention. 1 is a schematic configuration diagram illustrating an image forming apparatus according to an embodiment of the present invention. It is the front view which showed the preliminary charger and image holding body which concern on the comparison form with respect to embodiment of this invention.

  An example of a charger, an image forming unit, and an image forming apparatus according to an embodiment of the present invention will be described with reference to FIGS. In the drawing, an arrow H indicates the vertical direction of the apparatus (vertical direction), an arrow W indicates the apparatus width direction (horizontal direction), and an arrow D indicates the depth direction of the apparatus (horizontal direction).

(overall structure)
The image forming apparatus 10 according to the present embodiment is an electrophotographic image forming apparatus that uses a developer containing a negatively charged toner and a magnetic carrier. As shown in FIG. 6, the image forming apparatus 10 includes a storage unit 14 that stores a sheet member P as a recording medium from below to above in the vertical direction (arrow H direction), and a storage unit 14. A conveying unit 16 that conveys the accommodated sheet member P, an image forming unit 20 that forms an image on the sheet member P conveyed by the conveying unit 16 from the accommodating unit 14, and an original reading unit 22 that reads the read original G. Are provided in this order.

[Container]
The accommodating portion 14 includes an accommodating member 26 that can be pulled out from the apparatus main body 10 </ b> A of the image forming apparatus 10 to the near side in the apparatus depth direction, and the sheet member P is stacked on the accommodating member 26. Further, the accommodating portion 14 is provided with a delivery roll 32 that sends the stacked sheet members P to the conveyance path 28 that constitutes the conveyance portion 16.

[Transport section]
The transport unit 16 includes a plurality of transport rolls 34 that transport the sheet member P along a transport path 28 along which the sheet member P is transported.

[Original reading section]
The document reading unit 22 includes an optical device 44 that reads the read document G conveyed by the automatic document conveyance device 40 that conveys the read document G.

(Image forming part)
As shown in FIG. 5, the image forming unit 20 has a cylindrical shape extending in the depth direction of the apparatus and rotating in the R1 direction (clockwise) in the drawing, and an outer peripheral surface 56A of the image holding body 56 having a negative polarity. And a pre-charger 58 as an example of a charger that pre-charges to a predetermined potential. Further, the image forming unit 20 has an outer peripheral surface 56A of the image carrier 56 precharged by the precharger 58 in the direction of the axis of rotation of the image carrier 56 and a sheet passing region through which the sheet member P passes. A neutralization device 69 composed of a light emitting element for reducing a negative potential difference generated between the sheet non-passing region other than the sheet and neutralizing the potential near zero, and a surface potential neutralized by the neutralization device 69 can be determined in advance. A scorotron-type main charger 60 for charging to a negative potential within the above range is provided. Further, the image forming unit 20 includes an exposure device 62 (see FIG. 6) that irradiates the outer peripheral surface 56A of the image carrier 56 charged by the charger 60 with exposure light to form an electrostatic latent image, and the outer peripheral surface. And a developing device 64 that develops the electrostatic latent image formed on 56A as a toner image.

  Further, the residual toner remaining on the outer peripheral surface 56A of the image carrier 56 from the outer peripheral surface 56A on the downstream side of the preliminary charger 58 and on the upstream side of the main charger 60 in the rotation direction of the image carrier 56. A rotary brush 66 and a removal blade 68 for removal are provided. The rotating brush 66 and the removing blade 68 are arranged in this order in the rotation direction of the image carrier 56.

  The rotating brush 66 is rotated following the rotating image carrier 56 to remove residual toner from the outer peripheral surface 56A, and one end of the removal blade 68 is attached to the outer peripheral surface 56A of the image carrier 56. Residual toner or the like is removed from the outer peripheral surface 56A by contact.

  Further, the image forming unit 20 includes a transfer device that transfers a toner image formed on the surface of the image holding member 56 to the conveyed sheet member P at a transfer position T where the image holding member 56 and the transfer roll 70 are in contact with each other. An example transfer roll 70 is provided. Further, the image forming unit 20 includes a fixing device 74 (see FIG. 6) that heats and pressurizes the toner image on the sheet member P and fixes the toner image on the sheet member P.

  Then, in the rotation direction of the image carrier 56, the preliminary charger 58, the rotating brush 66, the removal blade 68, the main charger 60, the exposure device 62, and the developing device 64 are arranged in this order on the downstream side of the transfer position T. Has been placed.

  Further, the image carrier 56, the preliminary charger 58, the rotating brush 66, the removal blade 68, the main charger 60, and the developing device 64 constitute an image forming unit 72. The image forming unit 72 is the apparatus main body 10A. (See FIG. 6). Details of the preliminary charger 58 will be described later.

(Operation of the overall configuration)
In the image forming apparatus 10 described above, an image is formed as follows.

  First, the precharger 58 to which a voltage is applied precharges the outer peripheral surface 56A of the image carrier 56 to a negative potential. The main charger 60 to which the voltage is applied charges the outer peripheral surface 56A of the image carrier 56 precharged by the precharger 58 uniformly to a negative potential at a predetermined potential. Subsequently, based on the image data read by the document reading unit 22 or data input from the outside, the exposure device 62 irradiates the outer peripheral surface 56A of the image holding member 56 charged with exposure light to form an electrostatic latent image. Let it form. Further, the electrostatic latent image is developed by the developing device 64 and visualized as a toner image.

  Therefore, the sheet member P sent out from the storage member 26 to the transport path 28 by the sending roll 32 is sent out to the transfer position T. Then, a transfer voltage is applied to the transfer roll 70 from a power source (not shown), and a potential difference is generated between the transfer roll 70 and the image carrier 56. As a result, the transfer roll 70 transfers the toner image on the image holding member 56 to the sheet member P at the transfer position T.

  The toner image transferred to the sheet member P is fixed to the sheet member P when the sheet member P is heated and pressurized by the fixing device 74. Then, the sheet member P on which the toner image is fixed is discharged to the outside of the apparatus main body 10A by the transport roll 34.

  Further, the preliminary charger 58 to which a voltage is applied preliminarily charges the outer peripheral surface 56 </ b> A of the image carrier 56. The rotating brush 66 and the removing blade 68 remove residual toner and the like remaining on the outer peripheral surface 56A from the outer peripheral surface 56A of the image carrier 56 precharged by the precharger 58.

(Main part configuration)
Next, the preliminary charger 58 will be described.

  The preliminary charger 58 is a corotron type charger, and as shown in FIG. 4, a shield case 102 as a housing, a discharge wire 108 as an example of a discharge electrode to which a voltage is applied, and a discharge wire And a cleaning member 120 in contact with 108. Further, the preliminary charger 58 includes a moving member 130 (see FIG. 1) that moves the cleaning member 120.

[Shield case]
The shield case 102 is made of stainless steel, and an opening 102A is formed on the shield case 102 on the image carrier 56 side. Furthermore, as shown in FIG. 1, the shield case 102 extends along the axial direction of the image carrier 56 (the apparatus depth direction). A long hole 104 (see FIG. 4) extending in the depth direction of the apparatus is formed in the upper wall 102C of the shield case 102.

[Discharge wire]
The discharge wire 108 is made of a metal wire such as tungsten, is disposed in the shield case 102, and extends in the apparatus depth direction. Further, the discharge wire 108 is attached to each of the pair of side walls 102 </ b> B whose wall faces in the apparatus depth direction in the shield case 102.

  Then, a voltage is applied to the discharge wire 108 from a power source (not shown) to cause corona discharge, so that the precharger 58 precharges the outer peripheral surface 56A of the image carrier 56 to a negative polarity.

  Here, the preliminary charger 58 precharges the outer peripheral surface 56A of the image carrier 56 (before the main charger 60 charges the outer peripheral surface 56A of the image carrier 56, the outer peripheral surface 56A of the image carrier 56 is charged in advance. Explain why.

  When the toner image is transferred from the image carrier 56 to the sheet member P, as shown in FIG. 1, a portion (E1 in the drawing) of the outer peripheral surface 56A of the image carrier 56 through which the sheet member P passes in the depth direction of the apparatus. ) And a portion (E2 in the figure) through which the sheet member P does not pass. In the portion E2 where the sheet member P does not pass through the outer peripheral surface 56A, a potential difference is generated between the image carrier 56 and the transfer roll 70 without passing through the sheet member P. For this reason, the potential of the portion E2 of the outer peripheral surface 56A after the toner image is transferred to the sheet member P at the transfer position T is greatly different from the potential of the portion E1.

  The preliminary charger 58 precharges the outer peripheral surface 56A of the image carrier 56, so that the outer peripheral surface 56A is charged to a negative potential having a constant potential difference between E1 and E2. Further, the neutralizing device 69 neutralizes the outer surface 56A to near zero potential, and the degree of charging unevenness (difference between the potential of the portion E2 and the potential of the portion E1) in the rotation axis direction is reduced. Specifically, the portion of E1 that is negatively charged larger than the portion E2 is mainly neutralized by the static eliminator 69, thereby reducing the degree of uneven charging on the outer peripheral surface 56A.

  As described above, when the charging device 60 charges the outer peripheral surface 56A of the image holding member 56 by reducing the degree of uneven charging of the outer peripheral surface 56A by the action of the preliminary charger 58 and the charge eliminating device 69, the image is obtained. The outer peripheral surface 56A of the holding body 56 is charged to a potential within a predetermined range.

  That is, the reason why the precharger 58 precharges the outer peripheral surface 56A of the image carrier 56 and removes the electric charge by the static eliminator 69 is that the outer peripheral surface 56A of the image carrier 56 is within a predetermined range by the charger 60. This is because the potential is charged.

[Cleaning member]
As shown in FIG. 3, the cleaning member 120 is disposed in the shield case 102 and is provided as a pair. One cleaning member 120 </ b> A and the other cleaning member 120 </ b> B have the same configuration, and unless otherwise distinguished, “A” and “B” at the end of the reference numerals are omitted.

  As shown in FIG. 4, the cleaning member 120 includes a pair of pads 112 that sandwich the discharge wire 108 and a support member 110 that supports the pair of pads 112.

  Each of the pair of pads 112 has a rectangular parallelepiped shape, and is formed of a foam or a nonwoven fabric.

  The support member 110 extends upward from the U-shaped main body portion 110A opened on the image carrier 56 side and the upper end side portion of the main body portion 110A when viewed from the depth direction of the apparatus, and passes through the long hole 104 to the outside. And a protruding portion 110B that protrudes. Furthermore, the support member 110 includes a cylindrical portion 110C that is connected to the tip of the protrusion 110B. A lead shaft 122 described later is screwed into the cylindrical portion 110C. Thereby, the cleaning member 120 moves when the lead shaft 122 described later rotates, and the cleaning member 120 cleans the discharge wire 108.

  In a non-operating state in which the discharge wire 108 is not cleaned, the pair of cleaning members 120 are arranged at the standby position as shown in FIG. 1 and are arranged in contact with the central portion of the discharge wire 108 in the apparatus depth direction. It is out.

  That is, the pair of cleaning members 120 arranged at the standby position faces the central portion of the outer peripheral surface 56A of the image carrier 56 in the apparatus depth direction. That is, when the precharger 58 charges the outer peripheral surface 56A of the image holding member 56, the charge amount of the central portion of the outer peripheral surface 56A of the image holding member 56 in the apparatus depth direction is smaller than that of other parts. .

  Here, as described above, the preliminary charger 58 mainly charges the portion E2 of the outer peripheral surface 56A where the potential is significantly different from the portion E1, thereby reducing the degree of charging unevenness of the outer peripheral surface 56A. That is, the charge amount for the portion E1 by the preliminary charger 58 may be smaller than the charge amount for the portion E2. A portion E1 of the outer peripheral surface 56A includes a central portion of the outer peripheral surface 56A. That is, even if the charge amount of the central portion of the outer peripheral surface 56A of the image holding member 56 in the depth direction of the apparatus is smaller than that of other portions, the degree of charging unevenness of the outer peripheral surface 56A by the preliminary charger 58 is reduced. Get smaller.

(Moving member)
As shown in FIG. 1, the moving member 130 includes a lead shaft 122 that extends in the apparatus depth direction, and a motor 126 that rotates the lead shaft 122.

  As shown in FIGS. 1 and 3, the lead shaft 122 has a cylindrical main body portion 122A and spiral threads 122B and 122C formed on the outer peripheral surface of the main body portion 122A.

  The screw thread 122B is formed on one side (left side in FIG. 1) with respect to the central part of the main body part 122A, and the screw thread 122C is on the other side (left side in FIG. 1) with respect to the central part of the main body part 122A. It is formed in the part. In addition, the winding direction of the screw thread 122B is opposite to the rotation direction of the screw thread 122C.

  The cylindrical portion 110C of the cleaning member 120A is screwed with the portion where the thread 122B is formed on the lead shaft 122, and the cylindrical portion 110C of the cleaning member 120B is formed with the thread 122C on the lead shaft 122. The part is screwed.

  Further, both end portions in the apparatus depth direction in the main body 122A are supported by frames 132 and 134 of the apparatus main body 10A via bearings (not shown). A gear 122D is attached to the other side portion of the main body 122A. A gear 126B that meshes with the gear 122D is attached to the output shaft 126A provided in the motor 126.

  As a result, when the motor 126 operates, the lead shaft 122 rotates in the forward direction or the reverse direction via the gear 126B and the gear 122D.

[Others]
The preliminary charger 58 includes a control unit 150 that controls the operation of the motor 126. The control of the motor 126 by the control unit 150 will be described together with the operation described later.

(Function)
Next, the operation of the preliminary charger 58 and the configuration and operation of the preliminary charger 300 according to the comparative example will be described. First, the configuration of the preliminary charger 300 according to the comparative example will be described. Note that the configuration of the preliminary charger 300 will be described mainly with respect to the differences from the configuration of the preliminary charger 58.

  As shown in FIG. 7, the shield case 302, the discharge wire 308, and the lead shaft 312 of the precharger 300 are in the depth direction of the apparatus as compared with the shield case 102, the discharge wire 108, and the lead shaft 122 of the precharger 58. The other side is enlarged.

  The lead shaft 312 has a cylindrical main body 312A and a helical thread 312B formed from one end to the other end on the outer peripheral surface of the main body 312A. Further, the preliminary charger 300 includes a single cleaning member 120 and a control unit 350 that controls the operation of the motor 126.

  When the image forming apparatus 10 is operating so that a toner image is formed on the outer peripheral surface 56 </ b> A of the image holding member 56, the cleaning member 120 is in a non-operating state in which the discharge wire 308 is not cleaned. The non-operating cleaning member 120 is disposed at the standby position, and is stopped at the other side of the discharge wire 308 in the apparatus depth direction. Specifically, the cleaning member 120 disposed at the standby position does not face the outer peripheral surface 56 </ b> A of the image carrier 56.

  Next, the operation of the preliminary charger 300 will be described.

  In a state where the power supply of the image forming apparatus 10 is turned off, as shown in FIG. 7, one cleaning member 120 is in a non-operating state in which the discharge wire 308 is not cleaned. The non-operating cleaning member 120 is disposed at the standby position, and is stopped at the other side of the discharge wire 308 in the apparatus depth direction.

  When the image forming apparatus 10 is powered on, the control unit 350 operates the motor 126 and rotates the lead shaft 312 in the forward direction.

  When the lead shaft 312 rotates in the forward direction, the cleaning member 120 moves to one side (left side in the drawing) in the apparatus depth direction, and cleans the discharge wire 308. Further, when the cleaning member 120 moves to a position facing one end portion of the outer peripheral surface 56A of the image holding member 56 in the apparatus depth direction, the control unit 350 disables the motor 126. As a result, the cleaning member 120 stops at a position facing a portion on one end side of the image carrier 56 (see a two-dot chain line in the figure).

  When the cleaning member 120 stops, the control unit 350 operates the motor 126 and rotates the lead shaft 312 in the reverse direction.

  When the lead shaft 312 rotates in the reverse direction, the cleaning member 120 moves to the other side in the apparatus depth direction (right side in the figure). When the cleaning member 120 moves to the standby position, the control unit 350 deactivates the motor 126. As a result, the cleaning member 120 stops at the standby position. In this way, the cleaning member 120 cleans the discharge wire 308.

  When the cleaning of the discharge wire 308 is completed, the image carrier 56 rotates, and a voltage is applied to the discharge wire 308 from a power source (not shown) to generate corona discharge. The surface 56A is precharged to a negative polarity, and the charge removal device 69 removes the surface potential to near zero. As a result, the degree of uneven charging on the outer peripheral surface 56A of the image carrier 56 is reduced.

  Then, the charging device 60 charges the outer peripheral surface 56A of the image carrier 56 to a potential within a predetermined range in a state where the degree of uneven charging on the outer peripheral surface 56A of the image carrier 56 is reduced.

  Next, the operation of the preliminary charger 58 will be described. The operation of the precharger 58 will be mainly described in the difference from the operation of the precharger 300.

  In a state where the power of the image forming apparatus 10 is turned off, as shown in FIG. 1, the pair of non-operating cleaning members 120 are arranged at the standby position, and the discharge wire 108 is located on the center side in the apparatus depth direction. Lined up in contact with the part.

  When the power of the image forming apparatus 10 is turned on, the control unit 150 operates the motor 126 and rotates the lead shaft 122 in the forward direction.

  When the lead shaft 122 rotates in the forward direction, as shown in FIGS. 1 and 2A, the cleaning members 120A and 120B move separately so as to be separated from each other, thereby cleaning the discharge wire 108. That is, the cleaning members 120 </ b> A and 120 </ b> B move separately at the same time, and clean different areas in the discharge wire 108. Further, when the cleaning members 120A and 120B are moved to positions facing the end portion of the outer peripheral surface 56A of the image holding member 56 in the depth direction of the apparatus, sensors (not shown) detect the cleaning members 120A and 120B and control them. The unit 150 disables the motor 126. Accordingly, as shown in FIG. 2B, the cleaning members 120A and 120B are stopped at positions facing the end side portion of the outer peripheral surface 56A of the image carrier 56 in the apparatus depth direction.

  When the cleaning members 120A and 120B stop, the control unit 150 operates the motor 126 and rotates the lead shaft 122 in the reverse direction.

  When the lead shaft 122 rotates in the reverse direction, the cleaning members 120A and 120B move separately so as to approach each other. And if cleaning member 120A, 120B moves to a stand-by position, control part 150 will make motor 126 non-operation. Thereby, the cleaning members 120A and 120B stop at the standby position as shown in FIG. In this way, the cleaning members 120A and 120B clean the discharge wire 108.

  When cleaning of the discharge wire 108 is completed, the image carrier 56 rotates, and a voltage is applied to the discharge wire 108 from a power source (not shown) to generate corona discharge. The surface 56A is precharged to a negative polarity, and the charge removal device 69 removes the surface potential to near zero. As a result, the degree of uneven charging on the outer peripheral surface 56A of the image carrier 56 is reduced.

  Then, the charging device 60 charges the outer peripheral surface 56A of the image carrier 56 to a potential within a predetermined range in a state where the degree of uneven charging on the outer peripheral surface 56A of the image carrier 56 is reduced.

(Summary)
As described above, in the preliminary charger 300, the discharge wire 108 is cleaned by reciprocating the single cleaning member 120 along the discharge wire 308. On the other hand, the preliminary charger 58 cleans the discharge wire 108 by reciprocating two (a pair of) cleaning members 120 along the discharge wire 108. For this reason, the use of the preliminary charger 58 shortens the time for cleaning the discharge wire 108 as compared with the case where the preliminary charger 300 is used.

  In addition, the pair of cleaning members 120 arranged at the standby position are arranged in contact with the central portion of the discharge wire 108 in the apparatus depth direction. When cleaning the discharge wire 108, the cleaning members 120 </ b> A and 120 </ b> B arranged at the standby position move away from each other and move outward in the apparatus depth direction on the discharge wire 108. Thus, unlike the case where the pair of cleaning members at the standby position are respectively disposed at both ends of the discharge wire 108 in the depth direction of the apparatus, the substances attached to the discharge wire 108 are transferred from the discharge wire 108 to the apparatus. It is brought close to the both end sides in the depth direction.

  Further, in the image forming unit 72, the time for cleaning the discharge wire 108 is shortened, so that the cleaning of the discharge wire 108 is started after the cleaning of the discharge wire 108 is started as compared with the case where the preliminary charger 300 is provided. The time until the outer peripheral surface is charged to a potential within a predetermined range is shortened.

  Further, in the image forming apparatus 10, since the time for cleaning the discharge wire 108 is shortened, compared with the case where the preliminary charger 300 is provided, the cleaning of the discharge wire 108 is started and the sheet member P is applied to the sheet member P. The time until the toner image is transferred is shortened.

  Although the present invention has been described in detail with respect to specific embodiments, the present invention is not limited to such embodiments, and various other embodiments can be taken within the scope of the present invention. This will be apparent to those skilled in the art. For example, in the above-described embodiment, the preliminary charger 58 includes a pair (a plurality) of cleaning members 120. However, the charger 60 includes a pair (a plurality of) cleaning members, and the pair of cleaning members are moved separately. Also good.

  Further, in the above embodiment, the preliminary charger 58 includes a pair (a plurality) of cleaning members 120, but the preliminary charger 58 may include three or more cleaning members.

  Moreover, in the said embodiment, although the cleaning member 120 reciprocated and cleaned the discharge wire 108, you may clean the discharge wire 108 by moving one way.

  In the above-described embodiment, the toner image formed on the image carrier 56 is described as an example of the transfer method to the sheet member P. However, the toner image formed on the image carrier 56 is transferred to an intermediate transfer belt or the like. It may be a system in which the sheet is transferred to the sheet member P.

  In the above-described embodiment, the cleaning timing of the discharge wire 108 is after the power of the image forming apparatus 10 is turned on. However, the timing is not particularly limited to this timing. For example, a predetermined time has elapsed. The discharge wire 108 may be cleaned later.

  In the above embodiment, the image forming unit 72 includes the image carrier 56, the preliminary charger 58, the rotating brush 66, the removal blade 68, the main charger 60, and the developing device 64. The image carrier 56, the preliminary charger 58, and the main charger 60 may be provided.

10 Image forming apparatus 58 Preliminary charger (example of charger)
60 charger 62 exposure device 64 developing device 70 transfer roll (an example of transfer device)
72 Image Forming Unit 108 Discharge Wire (Example of Discharge Electrode)
120 Cleaning member 120A Cleaning member 120B Cleaning member 130 Moving member

Claims (5)

A discharge electrode facing the outer peripheral surface of the rotating image carrier and extending in the axial direction of the image carrier;
A plurality of cleaning members that are in contact with the discharge electrodes and are disposed at predetermined standby positions;
A moving member that separately moves the plurality of cleaning members arranged at a standby position along the discharge electrode;
With a charger. A pair of the cleaning members are provided, and the pair of cleaning members at the standby position are arranged in contact with the central portion in the axial direction of the discharge electrode,
The charger according to claim 1, wherein the moving member moves the pair of cleaning members in the standby position in the axial direction so as to be separated from each other, and then moves in the axial direction so as to approach each other. A rotating image carrier;
The charger according to claim 1 or 2, wherein the outer peripheral surface of the image carrier is precharged;
A main charger that charges the outer peripheral surface of the image carrier precharged by the charger to a potential within a predetermined range;
An image forming unit comprising: An image forming unit according to claim 3,
An exposure apparatus that irradiates the outer peripheral surface of the image carrier charged by the main charger with exposure light to form an electrostatic latent image;
A developing device for developing the electrostatic latent image formed on the outer peripheral surface of the image carrier as a toner image;
A transfer device for transferring a toner image formed on the outer peripheral surface of the image carrier to a recording medium;
An image forming apparatus comprising: A rotating image carrier;
The charger according to claim 1 or 2, wherein the outer peripheral surface of the image carrier is precharged;
A main charger that charges the outer peripheral surface of the image carrier precharged by the charger to a potential within a predetermined range;
An exposure apparatus that irradiates the outer peripheral surface of the image carrier charged by the main charger with exposure light to form an electrostatic latent image;
A developing device for developing the electrostatic latent image formed on the outer peripheral surface of the image carrier as a toner image;
A transfer device for transferring a toner image formed on the outer peripheral surface of the image carrier to a recording medium;
An image forming apparatus comprising:

Images