JPH096211A - Process cartridge and image forming device - Google Patents

Abstract

PURPOSE: To provide a process cartridge preventing the occurrence of an electrification memory and being made to be in the usable state when it is fitted to an image forming device. CONSTITUTION: The process cartridge removably fitted to the image forming device main body is provided with an electrophotographic photoreceptor 1, a developing sleeve 2 serving as a processing means acting on the electrophotographic photoreceptor 1, an electrifying roller 3, and short-circuiting means 4-7 short-circuiting the developing sleeve 2 and the electrifying roller 3 to the electrophotographic photoreceptor 1 with a conducting member located closely to the electrophotographic photoreceptor 1 in contact with it or not in contact with it, short-circuiting the developing sleeve 2 and the electrifying roller 3 together with a conducting member, and capable of releasing the short circuits.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus utilizing an electrophotographic process such as an electrophotographic copying machine, a laser beam printer, an LED printer, etc., and a process cartridge freely attachable to the image forming apparatus. .

[0002]

2. Description of the Related Art FIG. 2 is a schematic view of a process cartridge mounted in a general image forming apparatus. In this figure, reference numeral 1 denotes a photosensitive drum which is a latent image carrier, and conventionally, one using an organic photosensitive member as a photosensitive layer has been widely used. In a process cartridge of an image forming apparatus that forms an image by an electrophotographic method, it is usual that a plurality of conductive members are arranged in proximity to the photosensitive drum 1 as a process unit that acts on the photosensitive drum 1.

In FIG. 2, as an example of a conductive member,
Examples thereof include a developing sleeve 2 which is a developer carrying member formed of a non-magnetic metal tube, and a charging roller 3 which is a contact charging member formed of conductive rubber for uniformly charging the photosensitive drum 1. Here, the photosensitive drum 1, the developing sleeve 2, and the charging roller 3 have a drum ground electrode 6, a developing sleeve electrode 7, and a charging roller electrode 5, respectively.
Is connected. These electrodes come into contact with the electrodes provided in the image forming apparatus when the cartridge is attached to the image forming apparatus, and a bias necessary for the image forming process is applied to the electrodes. When it is taken out from the image forming apparatus before being attached or during use, it is in a non-contact floating state.

[0004]

The present invention is a further development of the prior art.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a process cartridge which prevents the occurrence of a charging memory and becomes usable when the process cartridge is mounted in the image forming apparatus, and an image forming apparatus.

[0006]

SUMMARY OF THE INVENTION The structure for achieving the object of the present invention is a process cartridge which is attachable to and detachable from an image forming apparatus main body having an electrophotographic photosensitive member and process means acting on the electrophotographic photosensitive member. A conductive member which is in contact or non-contact with the electrophotographic photosensitive member and is in close proximity to the electrophotographic photosensitive member, and a short-circuiting unit for short-circuiting the electrophotographic photosensitive member and the conductive member and capable of opening the short circuit. It is characterized by

In this structure, until the process cartridge is unpacked or the seal film is opened to enable the developer to be supplied to the developing container side, the conductive member and the latent image are separated by the short-circuiting means. Since the short circuit with the carrier is maintained, it is possible to prevent the occurrence of charging memory in the electrophotographic photosensitive member.

[0008]

【Example】

(First Embodiment) The process of the image forming apparatus used in this embodiment will be described with reference to FIG.

FIG. 3 is a schematic view of a general image forming apparatus.

In this figure, 1 is a photosensitive drum which is a latent image carrier, 2 is a developing sleeve which is a developer carrier, 3 is a charging roller which is a contact charging member for uniformly charging the photosensitive drum 1, 5 is a charging roller electrode for supplying a primary bias to the charging roller 3, 6 is a drum ground electrode for grounding the photosensitive drum 1, 7 is a developing sleeve electrode for supplying a developing bias to the developing sleeve, 12 is toner as a developer, Reference numeral 11 is a developing device provided with a developing sleeve 2 and toner 12, 13 is a cleaner unit for removing the toner 12 adhering to the photosensitive drum 1, 26 is a process cartridge including the above-mentioned process means, and 14 is a paper feed unit for guiding the paper into the main body. A paper device, 15 is a transfer device for transferring the toner 12 adhering to the photosensitive drum 1 onto the paper, 16 is a paper ejection device for ejecting the paper out of the main body, and 17 is a laser beam. An exposure device that irradiates the photosensitive drum 1 to form an electrostatic latent image on the photosensitive surface, 18 is a paper as a transfer material, 19 is a fixing device that fixes the toner 12 transferred onto the paper 18, and 100 is an image forming process. A high-voltage unit for supplying a high-voltage power source necessary for the image forming apparatus main body 20 is an image forming apparatus main body including the above apparatus.

The image forming process of this image forming apparatus will be described below.

The photosensitive drum 1 rotates in one direction around its axis. The surface of the photosensitive drum 1 is uniformly charged by the primary charging by the charging roller 3, and then an electrostatic latent image is formed by the laser light emitted from the exposure device 17. The developing sleeve 2 receives the supply of the toner 12 from the inside of the developing device 11,
The toner 12 is attached to the electrostatic latent image on the photosensitive drum 1 to make it visible. On the other hand, the paper feeding device 14 feeds the paper 18 as a transfer material from outside the image forming device 20 between the photosensitive drum 1 and the transfer device 15. The image of the photosensitive drum 1 visualized by the toner 12 is transferred onto the paper 18 by the transfer device 15.
The toner 12 transferred onto the paper 18 is fixed by the heat generated by the fixing device 19 and the applied pressure to form a recorded image.
After that, the paper 18 is transferred to the image forming apparatus 20 by the paper discharge device 16.
It is discharged to the outside. Then, after the residual toner remaining on the photosensitive drum 1 that has not been transferred is removed by the cleaner 13, the photosensitive drum 1 is again uniformly charged by the charging roller 3, and the above steps are repeated thereafter.

In the small-sized image forming apparatus having the above construction, the cartridge 26 is provided as the process means relating to the image formation.
It is usually configured to be installed in the main body of the device. When the cartridge 26 is mounted on the main body of the image forming apparatus, as shown in FIG. 3, the photosensitive drum 1, the developing sleeve 2, and the charging roller 3 are connected to the drum ground electrode 6, the developing sleeve electrode 7, and the charging roller 3. It is connected to the high voltage power supply 100 in the main body via the roller electrode 5.

The organic photosensitive drum and the charging memory for the photosensitive drum used in this embodiment will be described with reference to FIGS. 4 to 7. 4 to 6 are views showing one end surface side of a commonly used laminated type organic photosensitive drum, in which the photosensitive drum 1 includes a charge generating layer 1b, a charge transport layer 1b, a charge transport layer 1a, and a charge transport layer 1a on a conductive support 1a such as aluminum. The layer 1c is laminated in this order.

The charge generation layer 1b is formed of, for example, an azo pigment such as Sudan red or Diane blue, pyrenequinone,
It can be formed by dispersing a charge generating material such as quinone pigment such as anthanthrone in a binder resin such as polyvinyl butyral, polystyrene and acrylic resin and applying the dispersion. The thickness of such a charge generation layer is 5 μm or less, preferably 0.05 to 2 μm.

The charge transport layer 1c contains a polycyclic aromatic compound having a structure such as biphenylene or anthracene in the main chain or side chain, a nitrogen-containing ring compound such as indole or carbazole, a hydrazone compound or a styryl compound. It is formed using a coating liquid dissolved in a resin having film forming properties. As the resin having such a film forming property, polyester, polycarbonate, polystyrene,
Examples thereof include polymethacrylic acid ester. The thickness of the charge transport layer is 5 to 40 μm, preferably 10 to 30 μm. The charge transporting material may be used alone, or a sufficient effect can be obtained by mixing it with another charge transporting material.

The charging memory in the photosensitive drum 1 is considered to occur as follows. As shown in FIG. 4, when a positive charge is charged on the surface of the photoconductor, a negative charge is induced from the conductive support 1a. The negative charges move in the charge generation layer 1b toward the surface of the photoconductor, but remain in the interface 1d between the charge generation layer 1b and the charge transfer layer 1c because the charge transport layer 1c cannot transfer the negative charges. If a positive charge remains on the surface of the photoconductor for a long time,
The negative charge on the interface 1d is trapped in a deep trap and cannot move from the interface 1d even after the positive charge disappears.
Even if charging and exposure are repeated, it stays on the interface 1d for a while. Such a state is called a charging memory. As shown in FIG. 6A, when the charging memory portion is primarily charged by the charging roller (not shown) and then the charging memory portion is exposed as shown in FIG. The injection of positive charges into 1c is likely to occur, the sensitivity is apparently increased, and the charge on the surface of the photoconductor is lost in the charging memory portion more than other portions. FIG. 6B shows the surface potential of the photosensitive drum in this state. As shown here, since the positive charge is more likely to be injected when exposed at the location where the charging memory is caused, the potential on the exposed surface is lost because the charge on the photosensitive surface is lost more than at other portions. Bright part potential is lower than other places. For this reason, toner is less likely to adhere to the area where the potential is lowered in the regular development, so white toner is particularly noticeable in the halftone image, and more toner than usual is attached to the area where the potential is reduced in reversal development. It becomes an abnormal image that is more noticeable in black than the circumference.

The above is considered to be the mechanism of generation of the charging memory. In addition, it is considered that the electric charges that cause the generation of the charging memory are generated as follows.

1. Charging of the packing bag and the cartridge container The insulating packing bag and the cartridge container are charged by friction or the like, and the charge is discharged from the conductive member around the photosensitive drum to the drum.

2. User's static electricity The user's finger, which is charged, touches the electrode of the conductive member, and the charge is discharged from the conductive member to the drum.

3. Effect of external electric field When a cartridge is placed on a charged insulating resin, the charge is discharged from the conductive member to the drum.

As described above, the charge is transferred to the conductive member in the vicinity of the photosensitive drum 1, so that a potential difference is generated between the photosensitive drum 1 and the conductive member, and a positive charge is discharged from the conductive member to the photosensitive drum 1. It seems to be done. 2 and 3, the developing sleeve 2 or the charging roller 3 may be discharged to the photosensitive drum 1. Therefore, it is possible to prevent the occurrence of the charging memory by short-circuiting the photosensitive drum 1, the developing sleeve 2, and the charging roller 3 so that the potential difference that causes discharge may not occur.

The first embodiment of the present invention will be described with reference to FIG.

In FIG. 1, a conductive electrode short-circuit member 4 is attached to the cartridge 26 before packing, contacts the drum ground 6, the sleeve electrode 7 and the charging roller 5 to bring the photosensitive drum 1 and the photosensitive drum 1 close to each other. The developing sleeve 2 and the charging roller 3 which are conductive members are set to the same potential.

The electrode short-circuit member 4 used in this embodiment may be any one having conductivity, such as aluminum, chromium, nickel, stainless steel, copper,
Examples include those formed by contacting each electrode with a metal such as zinc, and those obtained by vapor-depositing aluminum, tin oxide, indium oxide, etc. on a plastic film.

The user removes the electrode short-circuit member 4 from the cartridge 26 before use, and then the cartridge 26
Is mounted in the main body of the image forming apparatus.

As a result, before the cartridge 26 is used, the photosensitive drum 1, the developing sleeve 2 and the charging roller 3 are short-circuited to have the same potential, so that the positive charge of the charged packaging bag or the like is electrically conductive in the vicinity of the photosensitive drum. Since there is no discharge from the conductive member to the photosensitive drum 1, the charging memory does not occur.

As described above, according to the present embodiment, since the charging memory can be always prevented before the cartridge is used, the charging memory by the positive charge of the charged packaging bag or the charging memory by the external electric field before the use is used. Can also be prevented.

(Second Embodiment) A second embodiment of the present invention will be described with reference to FIGS. 7 and 8. The present embodiment is characterized in that the member to be removed when using the cartridge has a function as an electrode short-circuit member.

The toner supply opening of the toner container 11 is sealed by the toner seal 10 so that the toner 12 as the developer does not leak from the toner container 11 until the cartridge is manufactured and shipped at the factory and used by the user. There is. The user holds the handle 9 immediately before using the cartridge, pulls out the toner seal 10 to open the toner supply opening, and then mounts the cartridge in the image forming apparatus.

A conductive member 31 is attached to the handle 9 for short-circuiting the electrodes.

The conductive member 31 used in this embodiment may be any conductive material, such as aluminum, chromium, nickel, stainless steel, copper,
Examples include those formed by contacting each electrode with a metal such as zinc, and those obtained by vapor-depositing aluminum, tin oxide, indium oxide, etc. on a plastic film.

The conductive member 31 contacts the drum ground 6, the charging roller electrode 5 and the sleeve electrode 7 when the cartridge is unused, that is, when the handle 9 is not pulled out.

As a result, the photosensitive drum 1, the developing sleeve 2, and the charging roller 3 are short-circuited to have the same potential, so that the positive charge of the charged packaging bag or the like is transferred from the conductive member near the photosensitive drum 1 to the photosensitive drum 1. Since it is not discharged to, the charging memory does not occur.

If the handle 9 is not pulled out, it interferes with the cartridge mounting opening of the image forming apparatus and the cartridge cannot be mounted in the image forming apparatus. You can prevent forgetting.

As described above, according to the present embodiment, since the charging memory can be always prevented before the cartridge is used, the charging memory by the positive charge of the charged packaging bag or the charging memory by the external electric field before the use. Can also be prevented. It is also possible to prevent forgetting to remove the electrode short-circuit member.

(Third Embodiment) A third embodiment of the present invention will be described with reference to FIG. This embodiment is characterized in that the electrodes are always short-circuited when the cartridge is not mounted in the image forming apparatus.

The photosensitive drum 1 is covered by the drum shutter 8 when the cartridge is outside the main body to prevent deterioration due to external light and damage to the photosensitive surface. The drum shutter 8 moves to the dotted line portion in the drawing to expose the photosensitive drum 1 when the cartridge is mounted in the main body, and moves to the solid line portion in the drawing to move the photosensitive drum 1 when the cartridge is taken out of the main body. It has a structure that covers.

Here, the drum shutter 8 has a conductive member 3
1 is attached.

The conductive member 31 used in this embodiment may be any conductive material, such as aluminum, chromium, nickel, stainless steel,
Examples include those formed by contacting each electrode with a metal such as copper or zinc, and those obtained by vapor-depositing aluminum, tin oxide, indium oxide or the like on a plastic film.

The conductive member 31 contacts the drum ground 6, the charging roller electrode 5 and the sleeve electrode 7 when the cartridge is taken out from the image forming apparatus, that is, when the drum shutter 8 is closed.

As a result, the photosensitive drum 1, the developing sleeve 2, and the charging roller 3 are short-circuited to have the same potential, so that the positive charge of the charged packaging bag or the like is transferred from the conductive member close to the photosensitive drum 1 to the photosensitive drum 1. No charging memory is generated because it is never discharged. When the cartridge is mounted in the main body, the drum shutter 8 is opened, the conductive member 31 opens the drum ground 6, the charging roller electrode 5 and the sleeve electrode 7, and each electrode is an electrode provided in the main body of the image forming apparatus. Connect with.

As the electrode short-circuit member, a member that moves or deforms when the cartridge is attached to or detached from the main body may be independently attached instead of the drum shutter. FIG. 10 shows an example thereof, and instead of the drum shutter, a member 29 that moves by attaching and detaching the cartridge is used. The member 29 rotates to the dotted line when the cartridge is inside the main body, and the attached conductive member 31 opens each electrode.

Further, the electrode short-circuit member itself may move or deform. FIG. 11 shows an example of the spring material 32 instead of attaching the electrode short-circuit member to the drum shutter.
Is used. The spring member 32 is deformed into a dotted line to open each electrode when the cartridge is inside the main body.

As described above, according to the present embodiment, since the charging memory is always prevented before the cartridge is mounted in the image forming apparatus or when the cartridge is removed from the image forming apparatus, the charged packing bag is provided. It is also possible to prevent a charging memory due to positive charges such as the above, and a charging memory due to an external electric field received when it is taken out of the main body during use.

(Fourth Embodiment) The fourth embodiment of the present invention will be described with reference to FIG. FIG. 12 is a longitudinal cross-sectional view of the cartridge at the time of packaging and transportation. The present embodiment is characterized in that the electrode short-circuit member is a packing bag for a cartridge having a conductive layer on its inner surface.

Until the cartridge is packed and shipped at the factory and reaches the user's hand, the cartridge is packed in a light-shielding packing bag 2.
1 and is sandwiched between the packing materials 22 and 23 and stored in the packing box 27.

Here, the inner surface of the packing bag 21 has a resistance of 10 ⁸
The conductive layer 25 of Ω · cm or less has a conductive film 25 in which a conductive substance such as carbon is dispersed in a resin such as polyethylene, aluminum, indium oxide, tin oxide or the like is used as a plastic film. A vapor-deposited product can be used. At the time of packing, the conductive layer 25 is covered by the packing material 22 and the drum ground 6 and the sleeve electrode 7 are packed.
And is pressed against and in contact with the charging roller electrode 5.
As a result, the photosensitive drum 1, the developing sleeve 2, and the charging roller 3 are short-circuited to have the same potential, and the positive charge of the charged packaging bag or the like is not discharged to the photosensitive drum 1 from the conductive member adjacent to the photosensitive drum 1. Therefore, since the photosensitive drum is protected from the external electric field by the shield effect of the conductive layer, the charging memory is not generated.

As described above, according to this embodiment, when the cartridge is in the packing bag, it is possible to prevent the occurrence of the charging memory.

Although the process cartridge shows an example in which the photosensitive drum, the charger, the developing device and the cleaning device are integrated, the charging means, the developing means or the cleaning means as the process means and the electrophotographic photosensitive member are provided. An integrally formed cartridge, which can be attached to and detached from the main body of an image forming apparatus (for example, a copying machine, LBP, etc.), or at least one of a charging means, a developing means, and a cleaning means as a process means, and an electrophotographic photoreceptor. Which is made into a cartridge as a unit and can be attached to and detached from the main body of the image forming apparatus (for example, a copying machine, LBP, etc.), or at least the developing means as the process means and the electrophotographic photoreceptor are integrally made into a cartridge to form an image It may be detachable from the main body of the forming apparatus (eg, copying machine, LBP, etc.). .

[0051]

According to the first aspect of the present invention, when the electrophotographic photosensitive member and the conductive member are short-circuited and the process cartridge is mounted on the main body of the image forming apparatus to be in use, the short-circuit is caused. Since it can be opened to secure the necessary power supply to the conductive member, it is possible to prevent the occurrence of a charging memory of the electrophotographic photosensitive member and to prevent the operation of the process cartridge from being hindered.

According to the second aspect of the invention, the operation of removing the conductive short-circuit member, unpacking the process cartridge, and opening the seal film to enable the developer to be supplied to the developing container side can be performed. Until it is performed, the short-circuiting means maintains the short-circuit between the conductive member and the electrophotographic photosensitive member, so that it is possible to prevent charging memory from being generated in the electrophotographic photosensitive member during transportation, storage, or the like.

According to the third aspect of the present invention, the charging member and the exclusive image carrier are held in a short-circuited state while the process cartridge is being transported or stored, or when it is removed from the image forming apparatus main body. Therefore, even if the process cartridge is detached from the image forming apparatus or mounted, it is possible to prevent the charging memory from being generated in the electrophotographic photosensitive member.

According to the invention described in claims 4, 5, and 6,
It can be applied to various process cartridges, and a clear image can be obtained by mounting these process cartridges.

[Brief description of drawings]

FIG. 1 is a sectional view of a process cartridge showing a first embodiment, showing a short circuit state.

FIG. 2 is a cross-sectional view showing the configuration of the process cartridge of FIG.

FIG. 3 is a schematic view showing a configuration in which the process cartridge shown in FIG. 2 is attached to an image forming apparatus main body.

FIG. 4 is a diagram showing a generation process of a charging memory.

FIG. 5 is a diagram showing a generation process of a charging memory.

FIG. 6A shows a generation process of a charging memory, and FIG.
FIG. 6 is a diagram showing a surface potential.

FIG. 7 is a cross-sectional view of a process cartridge showing a second embodiment.

FIG. 8 is a perspective view showing the toner seal of FIG.

FIG. 9 is a cross-sectional view of a process cartridge showing a third embodiment.

FIG. 10 is a sectional view of a process cartridge showing a modification of the third embodiment.

FIG. 11 is a sectional view of a process cartridge showing a modified example of the third embodiment.

FIG. 12 is a view of the packed state of the cartridge according to the fourth embodiment as viewed from the longitudinal direction.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Photosensitive drum 2 ... Developing sleeve 3 ... Charging roller 4 ... Electrode short-circuit member 5 ... Charging roller electrode 6 ... Drum earth electrode 7 ... Developing sleeve electrode 11 ... Developing device 26 ... Cartridge container

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hiroshi Sato 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (6)

[Claims] 1. A process cartridge which has an electrophotographic photosensitive member and process means acting on the electrophotographic photosensitive member and which is detachable from the main body of the image forming apparatus. A process cartridge comprising: a conductive member that is in close contact with the conductive member; and a short-circuiting unit that can short-circuit the electrophotographic photosensitive member and the conductive member and open the short-circuit. 2. A process cartridge detachably mountable to an image forming apparatus main body having an electrophotographic photosensitive member and a process unit that acts on the electrophotographic photosensitive member, wherein the process cartridge is in proximity to the electrophotographic photosensitive member in a contact or non-contact manner. A conductive member, and a short-circuiting unit for short-circuiting the electrophotographic photosensitive member and the conductive member and enabling the short-circuiting to be opened. The short-circuiting unit can be mounted on the image forming apparatus main body. The process cartridge is characterized in that the short-circuit state is maintained until the above condition, and the short-circuit state is opened when the image forming apparatus is mounted in the main body. 3. A process cartridge detachably mountable to an image forming apparatus main body having an electrophotographic photosensitive member and process means acting on the electrophotographic photosensitive member, wherein the electrophotographic photosensitive member is brought into close contact with or not in contact with the electrophotographic photosensitive member. And a conductive member, and a short-circuiting unit for short-circuiting the electrophotographic photosensitive member and the conductive member and enabling the short-circuiting to be opened. The short-circuiting unit is removed from the image forming apparatus main body. In the process cartridge, the short-circuit state is maintained, and the short-circuit state is opened when the image forming apparatus is mounted on the main body. 4. A process cartridge according to claim 1, 2 or 3, wherein the developing means, the charging means, the cleaning means as the process means and the electrophotographic photosensitive member are integrally made into a cartridge. 5. The process cartridge according to claim 1, wherein any one of a developing unit, a charging unit and a cleaning unit as a process unit and an electrophotographic photosensitive member are integrally formed into a cartridge. . 6. An image forming apparatus for forming an image on a recording medium, wherein the process cartridge according to claim 1, 2, 3, 4 or 5 is attachable to and detachable from a main body of the image forming apparatus. An image forming apparatus comprising: mounting means for mounting and a transporting means for transporting the recording medium.