Image forming device having a member for preventing developer leakage

A development apparatus for use in an image forming device includes a developer storage chamber for storing developer, a developer carrier having a film of the developer formed thereon, wherein a visible image is formed when the film interacts with an electrostatic latent image, and a developer feed member arranged adjacent to the opening of the developer storage chamber and configured to feed developer from the developer storage chamber to the developer carrier. A developer leakage prevention member is located between the developer feed member and the developer carrier and an adhesive adheres to the developer leakage prevention member in the longitudinal direction of the opening. Also, a layer including an agent is formed between the adhesive and the developer feed member.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority from Japanese Patent Application No. 2005-246026, filed on Aug. 26, 2005, the entire subject matter of which is incorporated herein by reference.

FIELD

Aspects of the present invention relate to a development apparatus performing development using charged micro particles as a developer, a process cartridge, a development apparatus cartridge, and an image forming device using one of the above.

BACKGROUND

In a development apparatus wherein the developing processing is carried out using toner, which is provided as charged micro particles as a developer and by depositing the toner as an electrostatic latent image, there is a problem with the leakage of toner from the development apparatus. If the leakage of toner occurs, the interior of the image forming device using the development apparatus is stained. As a result, printing failure may occur and an operator's hands and clothes may be soiled with the toner when the operator replaces the development apparatus.

In the case of non-magnetic single component developing wherein a toner film is formed with a film thickness regulating blade on the developing roller having functions of conveyance while carrying the toner and faced against the electrostatic latent image to proceed with developing process, leakage of toner occurs easily around the developing rollers that are rotating.

In order to prevent the leakage of toner from the direction of both ends of the developing roller, as in Japanese Laid Open Patent Application Publication 2001-134080, a side seal constituting a substrate of an end-to-end developer leakage prevention member slides on the circumferential face of the both ends of the developing roller, and a double-faced tape is used for installation in the case of the development apparatus.

At both ends of the feed roller for feeding a toner to the developing roller, a side end toner leakage prevention member called a feed roller seal is arranged to face both ends and a side seal is installed in the development apparatus case to cover the feed roller seal and prevent the leakage of toner from both ends of the feed roller.

In a development apparatus, when the toner (developer) becomes empty, it is replaced with a new development apparatus and the old development apparatus is recycled. When recycling the development apparatus, the old side seal (end-to-end developer leakage prevention member) is removed from the development apparatus case and a new side seal is installed. However, as mentioned above, since the side seal is installed using a double-faced tape in the case of the development apparatus, the side seal may be broken unless it is peeled properly. Peeling the side seal becomes more troublesome since residual side seal and double-faced tape (double-faced adhesive) must be further peeled off from the case of the development apparatus. In addition, installing a side seal at an appropriate position in the development apparatus case can become difficult due to the presence of double-faced tape on the back of the side seal. If the side seal adheres to the case of the development apparatus, it can be difficult to change the position of the side seal. In addition, when changing the position of the side seal, wrinkles and stretches frequently occur, which causes leakage of toner.

SUMMARY

At least some aspects of the present invention provide a development apparatus, process cartridge, development apparatus cartridge, and image forming device wherein the leakage of toner due to inappropriate installation of the toner leakage prevention member can be prevented. According to at least some aspects, the task of removing the old side seal (end-to-end developer leakage prevention member) from the development apparatus case, and installing a new side seal may be simplified.

According to at least one aspect of the invention, a development apparatus for use in an image forming device includes a developer storage chamber for storing developer, a developer carrier having a film of the developer formed thereon, wherein a visible image is formed when the film interacts with an electrostatic latent image, and a developer feed member arranged adjacent to the opening of the developer storage chamber and configured to feed developer from the developer storage chamber to the developer carrier. A developer leakage prevention member is located between the developer feed member and the developer carrier and an adhesive adheres to the developer leakage prevention member in the longitudinal direction of the opening. Also, a layer including an agent is formed between the adhesive and the developer feed member.

In other illustrative aspects, the developer apparatus may include a case containing a developer storage chamber for storing developer, a developer carrier having a film of the developer formed thereon, wherein a visible image is formed when the film interacts with an electrostatic latent image, and a developer feed member arranged adjacent to an opening of the developer storage chamber and configured to feed developer from the developer storage chamber to the developer carrier. Also, the case may include a developer leakage prevention member located between the case and the developer carrier, an adhesive located between the case and the developer leakage prevention member and adhering to the developer leakage prevention member in the longitudinal direction of the opening, and a layer including an agent contacting the adhesive and the case.

DETAILED DESCRIPTION

Illustrative aspects of the present invention are explained below with reference to the attached drawings.

FIG. 1is a cross-sectional view showing an overall configuration of a laser beam printer1as an image forming device according to at least one aspect of the present invention. InFIG. 1, the laser beam printer1as an image forming device is equipped with a feeder unit for feeding a recording medium (e.g., paper) at the bottom of a body case2. The feeder unit includes a press plate10that is pressed with a spring (not shown), a feed roller11, and a friction separation member14. The recording medium is pressed by the press plate10against the feed roller11and with rotation of the feed roller11, a recording medium on the top of a stack (if more than one recording medium is present) is input between the feed roller11and the friction separation member14to feed the recording medium.

At the downstream side in the direction of recording medium transfer due to the rotation of the feed roller11rotating in the direction of the arrow inFIG. 1, a pair of resist rollers12and13is installed in a rotating position to carry the recording medium to the transfer position at a specified timing constituted by a photosensitive drum20and a transfer roller21to be discussed later.

The photosensitive drum20as a carrier of the electrostatic latent images is made of positively charged materials, for example, an organic photosensitive material primarily made of positively charged polycarbonate. Specifically, the photosensitive drum20includes a cylindrically-shaped aluminum cylindrical sleeve as a body, and a hollow drum forming a photoconductive layer with a specified thickness (e.g., approximately 20 μm) prepared by dispersing photoconductive resin in the polycarbonate. The cylindrical sleeve that is grounded is supported in a fully rotating manner through the body case2. Moreover, the photosensitive drum20is driven to be rotated in the direction of the arrow using a driving means (not shown).

A charger30is constituted of, for example, a Scorotron type charger for positive charging that generates corona discharge from a wire for charging such as tungsten.

A laser scanner unit40includes a laser generator (not shown) for generating laser beam L for forming electrostatic latent images on the photosensitive drum20, a polygon mirror (a pentahedron mirror)41to be rotated, a pair of lenses42and45, and reflective mirrors43,44and46.

In a development apparatus50, a toner storage chamber52containing a toner as a developer is constituted in a development apparatus case51, and an agitator53and a cleaning member54are installed in a fully rotating manner around the rotary shaft55in the toner storage chamber52. In this toner storage chamber52, positively charged non-magnetic one-component developer having an electrical insulation is stored as a toner. A light transmitting window56is installed at the side wall located at both edges of the rotary shaft55of the toner storage chamber52. Additionally, at the side of the photosensitive drum20of the toner storage chamber52, an opening A is made as an opening part of the development apparatus case and a developing chamber57connects to the toner storage chamber52via this opening A in order to perform a developing process. Also, a feed roller58as a developer feed roller and a developing roller59as a developer carrier are supported in a fully rotating manner. The feed roller58and the feed roller shaft58aconstitute a developer feed member in order to feed a toner in the toner storage chamber52to the developing roller59. The amount of toner on the developing roller59that is fed by the feed roller58is regulated to a specified layer thickness using a layer thickness regulating blade64having a thin plate elasticity.

The developing roller59contains a cylindrical substrate made of a conductive silicone rubber containing conductive carbon micro particles on the core metal made of stainless steel. Furthermore, a resin containing fluorine or a rubber material coat layer is constituted on this substrate. However, it is not always necessary that the substrate of the developing roller59be made of conductive silicone rubber; conductive urethane rubber may also be used.

Additionally, the toner stored in the toner storage chamber52is a positively charged non-magnetic one-component developer which contains toner base particles with a volumetric mean particle size of 10 μm with the particle size ranging from 5 μm to 15 μm. The particles are constituted in a spherical shape by suspension polymerization in which a known colorant such as carbon black and a charging control agent such as nigrosin, triphenylmethane, quaternary ammonium salts are added to a monomer mixture of styrene and acryl. The toner is then constituted by adding silica as an external additive on the surface of the toner base particles.

The transfer roller21is supported in a fully rotating manner and is made of a foaming elastomer having conductivity such as silicone rubber and urethane rubber. The transfer roller21is constituted such that a toner image on the photosensitive drum20is definitely transferred onto a recording medium when a voltage is applied.

The fixing unit70is installed at the downstream side in the transfer direction of the recording medium from the resist rollers12and13to the pressure contact units with the photosensitive drum20and the transfer roller21, and also includes a heated roller71and a pressing roller72. The toner image transferred on the recording medium is heated and pressed by the heated roller71and pressing roller72while being transferred to be fixed on the recording medium.

A pair of carriage rollers73and an ejection roller74for transferring the recording medium is installed at the downstream side in the direction of carriage in the fixing unit70, and an ejection tray75is provided at the downstream side of the ejection roller74.

The aforementioned photosensitive drum20, transfer roller21, charger30and development apparatus50are stored in a process cartridge2a, and the process cartridge2ais installed in a fully detachable manner to the laser beam printer1. Moreover, the development apparatus50is installed as a development apparatus cartridge in a fully detachable manner to the process cartridge2a.

In the laser beam printer1as in the aspects described above, when the surface of the photosensitive drum20is uniformly charged by the charger30and the laser beam L modulated according to the image information is irradiated from the laser scanner unit40, an electrostatic latent image is formed on the photosensitive drum20. This electrostatic latent image is visualized with a toner in the development apparatus50, and the visual image formed on the photosensitive drum20is then carried to a transfer position by the photosensitive drum20. To reach the transfer position, a recording medium is fed from the feed roller11via resist rollers12and13, and the visual image is imprinted on the recording medium by a transfer bias applied by the transfer roller21. In this case, the remaining toner on the photosensitive drum20after the transfer is recovered by the developing roller59in the developing chamber57.

Next, the recording medium is carried to the fixing unit70and inserted through the heated roller71and the pressing roller72in the fixing unit70so that the visual image on the recording medium is fixed on the recording medium by application of pressure and heat. The recording medium discharged to an ejection tray75above the laser beam printer1via a pair of the carriage rollers73and the ejection roller74.

Next, a sealing structure for the prevention of leakage of toner in the development apparatus50according to some aspects of the invention will be explained with reference toFIG. 2orFIG. 4along with the installation procedures.

FIG. 2AandFIG. 3Aare partially dotted oblique views showing a sealing structure of the case51in the development apparatus50according to at least one aspect of the inventions. Additionally,FIG. 2BandFIG. 3Bare the partially dotted oblique views seen from the direction of the arrow B inFIGS. 2A and 3A, respectively.

InFIG. 2A, the area indicated by the oblique lines is installed using a double-faced tape as a double-faced adhesive member as the sealing member explained below, which is divided into a side seal installation area100along the circumferential direction of the developing roller59, and a lower sealed area101along the longitudinal direction of the developing roller59in the lower position of the developing roller59.

In the side seal installation area100of the case51, an opening51cfor installing the feed roller58is formed in order to install a feed roller seal109. The feed roller seal109constitutes a side edge face developer leakage prevention member. The feed roller seal109can be a cubic urethane sponge (or other appropriate material that would prevent leakage) forming an opening109athe size of the feed roller shaft58a(seeFIG. 1) in the longitudinal direction of the feed roller58as indicated by the two-dotted broken parallel lines inFIG. 2A. This feed roller seal109is positioned such that it is installed to face the side end face of the feed roller58, and it is also installed so that one of the edges of the feed roller seal109faces a side face of the opening51c. The side end face of the feed roller58slides against a portion of the side end face of the side seal104(this element is shown inFIG. 3A) and the side face of the feed roller seal109so that it prevents leakage of the toner from the side end face of the feed roller58.

Additionally, the developing roller59is arranged such that a side face unit comes close to, but does not contact the side face unit51aof the developing roller storage unit in case51shown inFIG. 2A. The center point Q shown inFIG. 2Bindicates the position of the central rotational axis of the developing roller59.

Next, as shown inFIG. 3AandFIG. 3B, in order to prevent leakage of toner from both ends of the developing roller59, side seal104is installed with double-faced tape102. A Teflon® felt113constituting the upper-most layer of an end-to-end developer leakage prevention member is located on the upper face of the side seal104and extends to the side seal installation area100indicated by the two-dotted lines inFIG. 3B. InFIG. 4, Teflon® felt113installed with a double-faced tape102is shown to cover the side seal104. The end-to-end developer leakage prevention member according to illustrative aspects of the present invention includes the side seal104and Teflon® felt113.

The side seal104can be formed of a urethane sponge (e.g., Poron™ manufactured by the Rogers INOAC Foam Company) that has relatively high rigidity in comparison to other sponges and it can have a certain thickness to exhibit a specified pressure for compression when the developing roller59is installed. For instance, the thickness of the side seal104may be approximately 3 mm. When compressed against the developing roller59, the thickness of the side seal104may be approximately 1.5 mm. According to this aspect, the end-to-end developer leakage prevention member can be pressed with a specified pressure against the developing roller59.

As shown inFIG. 3B, the feed roller seal109is laminated with side seal104using the double-faced tape102adhered on the back of the side seal104. On the contact surface between the double-faced tape102and the feed roller seal109, a releasing layer200containing grease as a releasing agent is formed. The releasing agent may be any material, which allows the double-faced tape102and the feed roller seal109to be readily separated from each other when necessary (e.g., during servicing). For example, materials used in removing a plastic from a metal mold during a plug molding process could be used. Illustrative releasing agents included, but are not limited to, silicone oil, lubricant oil and fluorine solvents wherein fluorine resin is dispersed (e.g., Hanarl manufactured by Kanto Kasei), fluorine resin powder (e.g., Leblanc manufactured by Daikin Kogyo), silicone resin micro particles (e.g. Tospearl manufactured by Toshiba Silicone), etc. may also be used. In Fig. B, the releasing layer200is highlighted as a black layer. The amount of grease or releasing agent for forming the releasing layer200should be sufficient to allow the double-faced tape102to adhere to the feed roller seal109in an operating state while allowing the double-faced tape102to be separated from the feed roller seal200without damaging (e.g., removing portions of) the feed roller seal109in a repair/recycle or disassembly state when the side seal104can be removed from the case51. Additionally, in some aspects a new side seal104can be installed where it can be aligned on the contact surface and can be installed in the side seal installation area100in the case51without generating wrinkles and stretching.

Since the releasing layer200, such as grease, is constituted in the area partially between the double-faced tape102and the case51, the task of removing the side seal104from the case51becomes easier.

Additionally, according to one aspect if the releasing layer200is constituted only on the contact surface between the double-faced tape102and the feed roller seal109, high adhesive strength of the double-faced tape102on the back side of the side seal104relative to the case51can be maintained so that the leakage between the rotating developing roller59and the side seal104can be prevented.

The releasing layer200containing the releasing agent may also be constituted on the entire surface where the double-faced tape102on the back side of the side seal104is in contact with the case51. According to this aspect, the side seal104can be easily removed from the case51at the time of recycling the development apparatus50. Since the side seal104can be placed at an appropriate position while sliding it in the case51due to the lubrication of the releasing agent, stretches or wrinkles may be prevented in the side seal104. In addition, Teflon® felt113can be installed on the side seal104over the side seal installation area100in the case51so that the leakage of toner from the installation point of the side seal104may be further prevented while maintaining the adhesive strength between the double-faced tape102and the case51.

As shown inFIG. 4, a lower side seal105and a lower film114can be installed in the lower side seal installation area101in the case51. Although a PET (polyethylene terephthalate) sheet or a urethane rubber film may be used as the lower film114. Using a double-faced tape, a lower film114is placed partially on the lower seal installation area101, a part of the front frame51dof the case51, and a part of the lower side seal105so that the leakage of toner from the lower part in the longitudinal direction of the developing roller59in the opening of the development apparatus50can be prevented.

Moreover, a layer thickness regulating blade64is pressed in the longitudinal direction of the developing roller59. Since a blade back seal (not shown) is installed between the layer thickness regulating blade64and the case51, the leakage of toner from the upper part in the longitudinal direction of the developing roller59can be prevented.

As explained above, the leakage of toner from the upper portion of the developing roller59can be prevented by each sealing member in the upper end, end-to-end and the lower end of the development apparatus50.

When the toner of the development apparatus50is being recycled, a releasing layer200containing releasing agent is constituted on the contact surface between the double-faced tape102on the back of the side seal104and the base51, making the tasks of removal of the side seal104from the case51and the installation of a side seal104into the case51relatively easy.

If the releasing layer200is constituted on the contact surface between the double-faced tape102on the back of the side seal104and the feed roller seal109, the side seal104can be removed without damaging the feed roller109from the case51with a high level of reliability.

Although aspects of the present invention have been described above, the present invention is not limited by to the aforementioned aspects. Various modifications and changes can be made that fall within the scope of the present invention.