JP3355074B2 - Electrophotographic charging device and process cartridge - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging device detachably mounted on an electrophotographic apparatus such as a copying machine, a printer, a facsimile, and the like, and a process cartridge provided with the charging device.

[0002]

2. Description of the Related Art FIGS. 8 and 9 are side sectional views showing a printer device having a detachable process cartridge. FIG. 8 shows the printer device with a process cartridge mounted. FIG. 9 shows the printer apparatus in a state where an opening / closing section for exchanging a process cartridge and the like is opened. 1 is a photosensitive drum, 2 is a cleaning device in which a cleaning blade 2a is pressed against the photosensitive drum 1, 3 is a charger for uniformly charging the photosensitive drum 1, and 4 is a photosensitive drum 1 charged by the charger 3. Is scanned with a laser beam L, so that the photosensitive drum 1
An optical writing unit 5 for forming an electrostatic latent image on the photosensitive drum 1 is a developing device for developing the electrostatic latent image formed on the photosensitive drum 1 into a toner image with the toner T. Here, the photosensitive drum 1, the cleaning device 2, the charging device 3, and the developing device 5 are integrally formed as a process cartridge 6, and the process cartridge 6 is detachably mounted to a mounting position in the image forming apparatus. You.

Reference numeral 7 denotes a transfer roller in contact with the photosensitive drum 1, reference numeral 8 denotes a separation charger, reference numeral 9 denotes a discharge lamp, reference numeral 10 denotes a fixing device, reference numeral 11 denotes a power supply 12, a printed board 13, a controller board 14, and other electrical components. An electrical / control component case in which control components are stored; 15, an exhaust fan for preventing a rise in temperature inside the apparatus; 16, a paper feed cassette for storing recording paper P, which is a recording medium; The paper feed tray 18 is a paper output tray formed on the upper surface of the apparatus main body.
18 is extended / corresponding to the size of the recording paper P to be discharged.
The retractable stopper plate 18a is provided. 19 and 20 are
The recording paper P is fed from the paper cassette 16 and the paper tray 17 respectively.
, A pair of registration rollers, a pair of discharge rollers 22 for discharging the recording paper P to the discharge tray 18, and a pair of rollers 23 and 24 disposed on a conveyance path of the recording paper P, respectively. The sensor 23 is disposed upstream of the registration roller pair 21 and detects the recording paper P to control on / off of the registration roller pair 21 and detect a jam of the recording paper P. A signal is output, and the sensor 24 is disposed between the fixing device 10 and the discharge roller pair 22 to detect the recording paper P and output a signal for detecting the completion of the discharge of the recording paper P or a jam. I do.

Next, an image forming operation in the printer shown in FIG. 8 will be briefly described. The charger 3 generates a corona discharge from the charge wire 3a by applying a bias voltage to the charge wire 3a by a bias power supply (not shown), and uniformly charges the photosensitive drum 1 by the corona discharge. Optical writing unit 4
Forms an electrostatic latent image on the photosensitive drum 1 by scanning the uniformly charged photosensitive drum 1 with the laser beam L. The optical writing unit 4 includes a polygon mirror,
Laser light L from polygon motor and polygon mirror
And an optical component for deflecting the optical path of the optical writing device into a substantially U-shape.
Is disposed below the photosensitive drum 1. Developing device 5
Is a toner T which has been thinned and charged to a predetermined polarity.
Is transferred to the photosensitive drum 1, thereby developing the electrostatic latent image into a toner image.

On the other hand, the recording paper P separated and fed from the paper feed cassette 16 or the paper feed tray 17 is sandwiched by a pair of registration rollers 21, and the pair of registration rollers 21
The conveyance of the recording paper P is started in synchronization with the upper toner image. The transfer roller 7 transfers the toner image on the photosensitive drum 1 to the recording paper P at a contact portion with the photosensitive drum 1. The separation charger 8 neutralizes the electric charge of the recording paper P adhered to the photoconductor drum 1 by charging at the time of transfer, and facilitates the separation of the recording paper P from the photoconductor drum 1. Thereafter, the recording paper P is peeled from the photosensitive drum 1 by a separation claw or the like (not shown), and the photosensitive drum 1 from which the recording paper P has been peeled is charged by a neutralizing lamp 9 and irradiated with a neutralizing light. Is neutralized.

The recording paper P peeled off from the photosensitive drum 1 is conveyed to a fixing device 10 where the toner image is fixed by being heated and pressed in the fixing device 10, and then discharged by a discharge roller pair 22. The paper is discharged onto the tray 18.

In the above-described printer, the photosensitive drum 1, the cleaning device 2, the charging device 3 and the developing device 5 are integrally formed as a process cartridge 6 as described above. It is detachably attached to the attachment position inside. When replacing the process cartridge 6, as shown in FIG. 9, the open / close plate 18b forming a part of the paper discharge tray 18 is opened above the process cartridge 6, and the process cartridge 6 is disposed above the photosensitive drum 1. Opening / closing part 25 supporting members etc.
Is opened about the support shaft 26, the process cartridge 6 can be lifted upward from the mounting position.

[0008] A member such as the photosensitive drum 1 and the cleaning device 2 which needs to be replaced at regular intervals, or a developing device 5
By integrating members containing consumables such as the process cartridge 6, a plurality of members can be replaced at the same time, and the work of replacing them can be facilitated. The control unit (not shown) outputs an alarm to the operation unit 28 when detecting that the remaining amount of the toner T in the developing device 5 has become equal to or less than a predetermined value based on a signal from the toner sensor 27, for example. Then, the user is caused to display the replacement time of the process cartridge 6 by the operation unit 28.

However, the charging device 3 has a problem in that the toner T and dust adhere to the charge wire 3a in a relatively short time even under normal use conditions, and the charging ability for the photosensitive drum 1 is reduced. When the charging ability of the charger 3 is reduced, the photosensitive drum 1 charged by the charger 3 has uneven charging, which causes a deterioration in image quality of the toner image. In order to prevent such deterioration in the image quality of the toner image and maintain the image quality, it is necessary to periodically clean the charge wire 3a to remove the adhered matter. Generally, the cleaning cycle of the charge wire 3a required for maintaining the image quality is shorter than the replacement cycle of the process cartridge 6.

A charger for charging by corona discharge includes:
In order to easily clean the charge wire as described above, there is a device provided with a cleaning mechanism for the charge wire. For example, Japanese Patent Application Laid-Open No. 2-296270 discloses a charger provided with a cleaning mechanism for such a charge wire, a felt piece and a handle connected to the felt piece through a slit provided in a longitudinal direction of the shield plate. And a transfer charger that cleans the charge wire by moving the felt piece on the charge wire by manually moving the handle along the slit after being taken out of the apparatus main body.

[0011]

In the transfer charger described in Japanese Patent Application Laid-Open No. 2-296270, a felt formed with a slit for sandwiching a charge wire is formed by a flat surface of an insulating member moving along the charge wire. Is attached to the mounting part. Therefore, during a period in which the felt has a sufficient elasticity, the felt can be brought into contact with the charge wire in a pressurized state, and the foreign matter attached to the charge wire by the felt can be efficiently removed. . However, over time, the elastic force of the felt disappears in the vicinity of the contact portion with the charge wire, and the pressing force of the felt on the charge wire decreases, and the ability to remove foreign matter from the charge wire decreases.

Further, in the printer device shown in FIGS. 8 and 9, the process cartridge 6 including the charger 3 is provided.
Is generally reused as much as possible from the viewpoint of environmental protection and the like. For this reason, the process cartridge 6 removed from the printer device is recycled by exchanging the cleaning blade 2a, which is a consumable part, at the manufacturer or the like. At this time, the charger 3 is described in Japanese Patent Application Laid-Open No. 2-296270.
In the case of having a cleaning mechanism for the charge wire 3a as described in the publication, the cleaning member such as felt is also replaced with a new one as a consumable part. However, since the replacement of the cleaning member is performed within the case of the charger 3, the workability is poor. In particular, the operation of inserting the charge wire 3a into the slit of the cleaning member is performed in a completely closed state. It is very difficult because the charge wire 3a must be inserted into the inside.

[0013] An object of the present invention is to provide a cleaning means for a charge wire in which the ability to remove foreign substances from the charge wire over time is prevented and the cleaning member can be easily replaced. Provided is a charging device and a process cartridge provided with the charging device.

[0014]

According to a first aspect of the present invention, there is provided a charging device which is provided at a position opposed to an image bearing surface of a photoreceptor, and is provided with a corona when a charging voltage is applied. A charge wire for generating a discharge; and a cleaning means for supporting a cleaning member in contact with the charge wire so as to be movable along the charge wire. The image bearing surface is uniformly charged by corona discharge from the charge wire. In addition, in the charging device detachably mounted on the electrophotographic apparatus main body, the cleaning means has a slit for holding the charge wire formed therein, and a cleaning member formed of an elastic material; The cleaning member is movably supported along a line, and a part of the cleaning member is clamped in a pressurized state, and the cleaning member presses a charge wire in the slit. Characterized in that a holder member to form a shape portion and deformed portion bending to open near the slit inlet into a substantially V-shape.

According to a second aspect of the present invention, there is provided a process cartridge comprising: a photosensitive member; charging means for uniformly charging the image bearing surface of the photosensitive member; and the image bearing surface uniformly charged by the charging device. Developing means for developing the electrostatic latent image formed on the toner image into a toner image with toner, and removing the toner image remaining on the image bearing surface after transferring the toner image on the image bearing surface developed by the developing means to a recording medium. In a process cartridge which is provided with at least a cleaning means for collecting and is detachably attached to the main body of the electrophotographic apparatus, the charging device according to claim 1 is provided as the charging means.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side sectional view showing a configuration of an embodiment of a process cartridge according to the present invention. Members corresponding to those described with reference to FIGS. 8 and 9 are denoted by the same reference numerals and the description thereof will be omitted. Omitted. 30 is
Like the conventional process cartridge 6, the process cartridge is mounted at the mounting position in the printer shown in FIG. 8, and the process cartridge 30 includes a dividable developing unit cartridge 31 and a CTM (cleaning / toner magazine) unit cartridge 40. The CTM section cartridge 40 is configured to be able to be replaced independently at a different time from the development section cartridge 31. In the developing unit cartridge 31, 32 is a CTM as indicated by a two-dot chain line.
This is a storage section in which the toner tank section 41 below the unit cartridge 40 is stored. By storing the toner tank section 41 in the storage section 32, the developing section cartridge 31 and the CTM section cartridge 40 are integrally formed as the process cartridge 30. Assembled. Reference numeral 33 denotes a conveying member for bringing the toner T supplied from the CTM unit cartridge 40 into contact with the first developing roller 34, and reference numeral 35 denotes a charging blade for thinning and charging the toner T attached to the first developing roller 34. The toner T charged by the first developing roller 34 is transferred to the second developing roller 36, and the second developing roller 36 transfers the toner T to the photosensitive drum 1
The electrostatic latent image on the photosensitive drum 1 is developed into a toner image.

In the CTM unit cartridge 40,
41 is a toner tank unit for storing unused toner T, 42 is an agitator for stirring the toner T in the toner tank unit 41,
Reference numeral 43 denotes a replenishing roller for replenishing the developing unit cartridge 31 with the toner T agitated by the agitator 42, reference numeral 44 denotes a cleaning unit disposed on the upper part of the CTM unit cartridge 40, and reference numeral 45 denotes a handle provided on the upper surface of the cleaning unit 44. The user can easily exchange the CTM cartridge 40 by gripping the handle 45 when exchanging the CTM cartridge 40. 46 is the charge wire 46
a is a charger that generates a corona discharge by applying a charging voltage to a, 51 is an operation member disposed on the upper surface of the cleaning device 44, 52 is a support member supported by a shield case 46b of the charger 46, The operation member 51 and the holder member 52 constitute a part of a cleaning mechanism for a charge wire 46a described later.

When the developing unit cartridge 31 and the CTM unit cartridge 40 are assembled as a process cartridge 30, the CTM unit cartridge 40 is
A charger 46 disposed below 44 is opposed to the photosensitive drum 1. The cleaning device 44 includes a cleaning blade 44
a to the photosensitive drum 1 and press the cleaning blade 4
The toner T remaining on the photosensitive drum 1 after the transfer is completed is peeled off by 4a, and the peeled toner T is conveyed into the waste toner tank 44c by the magnet roller 44b.

When the remaining amount of the toner T stored in the toner tank portion 41 becomes less than a predetermined amount, the CTM portion cartridge 40 is replaced with a new one.
The time when an image is formed on 5000 sheets of recording paper P (A4 size, printing rate 5% conversion) is the replacement time. In addition, the developing unit cartridge 31 is degraded due to the deterioration of the photoconductor of the photosensitive drum 1.
The time when an image is formed on 45,000 sheets of recording paper P (A4 size, printing rate 5% conversion) is the replacement time.

FIG. 2 is a perspective view of a CTM portion cartridge in the process cartridge of the present embodiment, and FIG. 3 is a perspective view of a cleaning mechanism for a charge wire disposed in the CTM portion cartridge of the present embodiment. 53 is a rope-shaped connecting member connecting the operating member 51 and the holder member 52,
The operation member 51, the holder member 52, and the connecting member 53 form one loop as a whole. Further, guide grooves 44d are formed on the upper surface and side surfaces of the cleaning device 44, and the connecting members 53d are formed.
Is a guide groove 44d on the top and side surfaces of the cleaning device 44.
It is inserted so that it can move inside.

The charger 46 has a charge wire 46a stretched inside the shield case 46b so as to be parallel to the longitudinal direction of the image bearing surface of the photosensitive drum 1. The shield case 46b has a charge wire 46a parallel to the charge wire 46a. A large slit (not shown) is open. The holder member 52 inserts the arm portion 52a into the shield case 46b through the slit, is supported movably along the slit by the shield case 46b, and is a cleaning member fixed to a tip end portion of the arm portion 52a. A certain cleaning pad 54 is connected to a charge wire 46a.
Contact. Here, the cleaning pad 54
For example, it is formed of a material having a sufficient elasticity such as a felt material or a urethane foam material.

The guide groove 44d is parallel to the charge wire 46a on the upper surface of the cleaning device 44, that is, the photosensitive drum 1
The operating member 51 is formed so as to be movable along the guide groove 44d. When cleaning the charge wire 46a, the user grips the operation member 51 and reciprocates in the direction of the arrow A1 or the direction of the arrow A2, thereby causing the cleaning member 52 to move in the direction of the arrow B2 or B2.
Move in one direction. When the holder member 52 moves in the arrow B1 direction or the arrow B2 direction, the cleaning pad
The cleaning pad 54 slides on the charge wire 46a, and the cleaning pad 54 removes toner T, dust, and the like attached to the charge wire 46a.

FIGS. 4 and 5 are an exploded perspective view and a front view, respectively, showing a state before the cleaning pad is mounted on the holder member in the present embodiment, and FIGS. 6 and 7 respectively.
FIGS. 4A and 4B are a perspective view and a front view, respectively, showing a state in which a cleaning pad is mounted on a holder member in the present embodiment. In the cleaning pad 54 formed in a block shape, a slit 54a is formed on the front end surface so as to be parallel to the extending direction of the charge wire 3a, and a double-sided tape 5 is formed on the rear end surface.
5 is stuck. The holder member 52 is connected to a substantially U-shaped holding portion 52b at the tip of an arm portion 52a, and the holding portion 52b is formed of an elastic resin or the like.

The cleaning pad 54 is fixed to the holder member 52 by being inserted into the holding portion 52b and attaching the double-sided tape 55 to the holding portion 52b. The holding portion 52b holds the both sides of the cleaning pad 54 in parallel with the slit 54a to partially compress and deform the cleaning pad 54. At this time, the cleaning pad 54 is bent so as to be opened first by a reaction force from the cleaning pad 54. Deform. Specifically, w ₁ the pinching width of the pinching portion 52 b, the width of the cleaning pad 54 when the w ₂ which is sandwiched by the clamping portion 52b, w ₂ -w ₁ = 0.5
Cleaning pad 54 and holding part 5 so that
Form 2b. Here, since the cleaning pad 54 is merely fixed to the holding portion 52b by the adhesive force of the double-sided tape 55, it can be easily removed from the holding portion 52b.

When the depth h _{1 of} the holding portion 52b and the height h ₂ of the cleaning pad 54 held by the holding portion 52b are set, the cleaning pad 54 and the holding portion are set so that h ₂ −h ₁ ≧ 0.5 mm. Form 52b. As a result, as shown in FIG. 7, the cleaning pad 54 is held in a state in which the end on the slit 54a side projects 0.5 mm or more from the holding portion 52b.
Fixed to 52b.

The cleaning pad 54 for the holding portion 52b
At the time of mounting, the clamping portion 52b clamps the cleaning pad 54 and partially compresses and deforms the cleaning pad 54, and the end of the cleaning pad 54 on the slit 54a side projects 0.5 mm or more from the clamping portion 52b, The cleaning pad 54 has a substantially deformed portion 54b, which has been compressed and deformed in the width direction of the holding portion 52b, and a substantially V near the entrance of the slit 54a.
A bent portion 54c that is bent and deformed so as to open in a letter shape is formed. Here, the holder member 52 has a slit 54a
The cleaning pad 54 is supported so that the charge wire 46a sandwiched by the cleaning pad 54 is located at the compression deformation portion 54b.
As a result, the cleaning pad 54 always presses the charge wire 46a in the slit 54a by the compression deformed portion 54b that has been compressed and deformed.

In the charger 46 of this embodiment, even if the elastic force of the cleaning pad 54 decreases with time due to the compression deformation portion 54b of the cleaning pad 54 pressing the charge wire 46a in the slit 54a, A reduction in the pressure of the cleaning pad 54 on the charge wire 46a is prevented, and the charge wire 46
Since the cleaning ability of the cleaning pad 54 for removing foreign matter from a can be prevented from being reduced for a long time,
The cleaning mechanism makes it possible to always efficiently remove foreign substances adhering to the charge wire 46a.

Further, a bending deformation portion 54c is formed in the cleaning pad 54, which is bent and deformed so as to open the vicinity of the entrance of the slit 54a in a substantially V-shape. Since the work of inserting the charge wire 46a into the slit 54a becomes easy, the cleaning pad which is a consumable part
54 can provide a cleaning mechanism that is easily replaced.

[0029]

As described above, according to the first aspect of the present invention,
According to the charging device described above, the cleaning means is formed with a slit for holding the charge wire, is supported by a cleaning member formed of an elastic material, and is movably supported along the charge wire, and adds a part of the cleaning member. The cleaning member has a compression deforming portion that pressurizes the charge wire in the slit and a holder member that forms a bending deforming portion that opens the vicinity of the slit entrance in a substantially V-shape. Even if the elastic force of the member decreases over time, the pressure of the cleaning member against the charge wire is prevented from lowering, and the cleaning ability of the cleaning member that removes foreign matter from the charge wire when the cleaning mechanism operates is reduced. Since it can be prevented for a long time, it is possible to provide a charger equipped with a cleaning mechanism for efficiently removing foreign substances adhering to the charge wire, and to provide a cleaner. When replacing the member, since the task of interleave the charge wire to the slit of the cleaning member is facilitated, it is possible to provide a charger provided with a cleaning mechanism which is a consumable part cleaning member is easily replaced.

According to the process cartridge of the second aspect of the present invention, since the charging device of the first aspect is provided as the charging means, when the cleaning member is replaced,
Since the work of inserting the charge wire into the slit of the cleaning member is facilitated, the process cartridge can be easily recycled in a short time.

[Brief description of the drawings]

FIG. 1 is a side sectional view illustrating a configuration of an embodiment of a process cartridge of the present invention.

FIG. 2 illustrates a C in the process cartridge according to the exemplary embodiment.
It is a perspective view of a TM part cartridge.

FIG. 3 illustrates a C in the process cartridge according to the exemplary embodiment.
FIG. 9 is a perspective view of a cleaning mechanism for a charge wire arranged in the TM unit cartridge.

FIG. 4 is an exploded perspective view showing a state before a cleaning pad is attached to a holder member in the embodiment.

FIG. 5 is a front view showing a state before a cleaning pad is attached to a holder member in the embodiment.

FIG. 6 is a perspective view showing a state in which a cleaning pad is mounted on a holder member in the embodiment.

FIG. 7 is a front view showing a state in which a cleaning pad is mounted on a holder member in the embodiment.

FIG. 8 is a side cross-sectional view illustrating a printer device including a detachable process cartridge.

FIG. 9 is a side cross-sectional view illustrating a printer device including a detachable process cartridge.

[Explanation of symbols]

1: photoreceptor drum, 18b: open / close plate, 25: open / close unit, 3
0: Process cartridge, 31: Developing cartridge, 40: CTM cartridge, 41: Toner tank, 44: Cleaning device, 44a: Cleaning blade, 46: Charging device, 46a: Charge wire, 51: Operating member, 52: Holder member, 52b: clamping section, 53: connecting member, 54: cleaning pad, 54a: slit,
54b: compression deformation portion, 54c: bending deformation portion, T: toner.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03G 15/02 G03G 15/16 102 G03G 21/18

Claims (2)

(57) [Claims] 1. A charge wire which is stretched at a position facing an image bearing surface of a photoreceptor and generates a corona discharge when a charging voltage is applied, and a cleaning member in contact with the charge wire is moved along the charge wire. Cleaning means for supporting the image bearing member, the charging means being configured to uniformly charge the image bearing surface by corona discharge from the charge wire, and to be detachably mounted to the electrophotographic apparatus main body. A slit for holding the charge wire is formed, and a cleaning member formed of an elastic material is supported movably along the charge wire, and a part of the cleaning member is held in a pressurized state. A cleaning member having a compression deforming portion for pressing the charge wire in the slit and a bending deformation portion for opening the vicinity of the slit entrance in a substantially V-shape; Charging apparatus characterized by comprising: a da member. 2. A photoreceptor, charging means for uniformly charging an image bearing surface of the photoreceptor, and an electrostatic latent image formed on the image bearing surface, which is uniformly charged by the charging means, is toner-toned. At least a developing unit for developing an image, and a cleaning unit for collecting toner remaining on the image bearing surface after transferring the toner image on the image bearing surface developed by the developing unit to a recording medium are arranged, A process cartridge detachably mounted to an apparatus main body, wherein the charging device according to claim 1 is provided as the charging unit.