JP2008164664A - Image holder device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To decrease drastic attenuation of a potential caused by a hole trap during photo-destaticization by a light in an image holder having a surface layer. <P>SOLUTION: An image forming apparatus (U) is disclosed, which is equipped with an image holder (PRy), having a protective layer (15) formed on the surface to protect the inside; a non-contact discharge type charger (CCy) for charging the surface of the image holder (PRy); a transfer device (T1y) for transferring a toner image on the surface of the image holder (PRy); an image holder cleaner (CLy) for cleaning the surface of the image holder (PRy), after an image is transferred by the transfer device (T1y); a non-contact discharge type pre-cleaning destaticizer disposed in the downstream side of the transfer device (T1y) and on the upstream side of the image holder cleaner (CLy) and imparting charges to the surface of the image holder (PRy); and an optical-destaticizer (2y) disposed on the downstream side of the transfer device (T1y) and the upstream side of the image holder cleaner (CLy) and irradiating the surface of the image holder (PRy) with light for destaticization. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image carrier device and an image forming apparatus.

Conventionally, in an image forming apparatus such as an electrophotographic copying machine, a printer, or a fax machine, an electrostatic latent image is formed on the surface of an image carrier charged by a charger, and the latent image is developed into a toner image. Is transferred and fixed on the medium to form an image.
As such an image forming apparatus, Patent Document 1 (Japanese Patent Laid-Open No. 8-016052) discloses a photoreceptor mainly composed of arsenic triselenide, a charger for charging the surface of the photoreceptor, and a center wavelength of 660. An image exposure light source for writing a latent image by irradiating light of up to 700 nm, a developing machine for developing the latent image with a two-component developer, a static elimination lamp for irradiating the developed photoreceptor surface with static elimination light before transfer, and paper An image having a transfer device that transfers a toner image to the surface, an AC corona discharger that discharges toner on the surface of the photoreceptor after transfer, a cleaning device that scrapes off the toner, and an erase lamp that discharges the surface of the photoreceptor after cleaning. A forming apparatus is described.

Further, the image holding body is often configured to be detachable as a detachable body, that is, a detachable unit that can be replaced when a lifetime or failure occurs. The detachable unit is required to have a long life, but when the detachable unit has a long life, it is necessary to extend the life of the image carrier. The surface of the image holding member is worn by a rubbing member, a cleaning member such as a so-called cleaning blade or cleaning brush, a medium, an intermediate transfer member, and the like, so that the film on the surface is reduced and the life is reached. In response to this, a photoreceptor having a cured surface layer made of a crosslinked resin or the like on the surface of an image carrier is often used.
As an image carrier having such a surface layer, Patent Document 2 (Japanese Patent Laid-Open No. 9-190004) discloses that a conductive layer, an undercoat layer, a charge generation layer, a charge transport layer, a surface layer are formed on a support surface. An electrophotographic photoreceptor formed in order is described.

JP-A-8-016052 ("0014" to "0016", "0027", "0047" to "0049", FIG. 1) JP-A-9-190004 ("0050" to "0063", FIGS. 1 and 2)

  An object of the present invention is to suppress an increase in a necessary current value in a charger in an image carrier having a protective layer.

In order to solve the technical problem, an image carrier apparatus according to claim 1,
A rotating image carrier having a conductive substrate, a charge generation layer for generating charges, a charge transport layer for transporting charges generated in the charge generation layer, and a protective layer formed on the surface and protecting the interior; ,
A charger for charging the surface of the image carrier;
An image carrier cleaner for cleaning the surface of the image carrier that has passed through a transfer region to which a toner image formed on the charged surface is transferred;
A non-contact discharge type pre-cleaning static eliminator disposed on the downstream side of the transfer region and the upstream side of the image carrier cleaner with respect to the rotation direction of the image carrier, and applying charge to the surface of the image carrier;
An optical static eliminator that is disposed downstream of the transfer region and upstream of the image carrier cleaner with respect to the image carrier rotation direction, and irradiates the surface of the image carrier with static elimination light;
It is provided with.

The image carrier device according to claim 2 is the image carrier device according to claim 1,
The optical static eliminator disposed on the downstream side of the pre-cleaning static eliminator and the upstream side of the image carrier cleaner with respect to the image carrier rotational direction;
It is provided with.

The image carrier device according to claim 3 is the image carrier device according to claim 1 or 2,
The light static eliminator disposed downstream of the transfer region and upstream of the pre-cleaning static eliminator with respect to the image carrier rotation direction;
It is provided with.

The image carrier device according to claim 4 is the image carrier device according to claim 3,
The static eliminator before cleaning, comprising: a discharge unit for generating electric charge; and a discharge uniformizing member for uniformly charging the surface of the image carrier by the electric charge generated in the discharge unit;
It is provided with.

The image carrier device according to claim 5 is the image carrier device according to any one of claims 1 to 4,
A second light static eliminator disposed downstream of the image carrier cleaner and upstream of the charger with respect to the image carrier rotation direction;
It is provided with.

The image carrier device according to claim 6 is the image carrier device according to any one of claims 1 to 5,
The protective layer having a crosslinked structure containing a charge transporting material having at least one reactive group that forms a crosslinked structure with a crosslinkable resin;
It is provided with.

The image carrier device according to claim 7 is the image carrier device according to claim 6,
The crosslinkable resin is a phenol derivative.

The image carrier device according to claim 8 is the image carrier device according to claim 6,
The crosslinkable resin is a siloxane resin.

An image forming apparatus according to claim 9 is provided.
An image carrier device according to any one of claims 1 to 8,
A latent image forming apparatus that forms an electrostatic latent image on the surface of the image carrier charged by the charger;
A developing device for developing the electrostatic latent image formed on the surface of the image carrier;
A transfer device for transferring the toner image on the surface of the image carrier;
It is provided with.

According to the first aspect of the present invention, it is possible to suppress an increase in the required current value in the charger in the image carrier having the protective layer as compared with the case where the present invention is not adopted.
According to the second aspect of the present invention, compared to the case where the present invention is not adopted, since the distance from the light static eliminator to the charger is long, the holes are sufficiently released and the dark decay can be reduced. .
According to the third aspect of the present invention, the charge can be removed by the optical charge eliminator before the electric charge is applied by the pre-cleaning charge eliminator. A necessary current value can be reduced.

According to the fourth aspect of the present invention, as compared with the case where the present invention is not adopted, the potential unevenness on the surface of the image carrier can be reduced by the pre-cleaning static eliminator.
According to the fifth aspect of the present invention, even if the surface of the image carrier is shielded by the residual toner adhered after the transfer, the second light static eliminator can suppress charging unevenness due to the charger.

According to the sixth aspect of the present invention, it is possible to form a protective layer having charge transporting properties and high wear resistance.
According to invention of Claim 7, a protective layer can be formed with a phenol derivative.
According to invention of Claim 8, a protective layer can be formed with a siloxane resin.
According to the invention described in claim 9, compared to a case where the present invention is not adopted, an image holding member having a protective layer is used, while suppressing a required current value in the charger from being increased, It can cope with high-speed image formation.

Next, examples which are specific examples of embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following examples.
In order to facilitate understanding of the following description, in the drawings, the front-rear direction is the X-axis direction, the left-right direction is the Y-axis direction, the up-down direction is the Z-axis direction, and arrows X, -X, Y, -Y, The direction indicated by Z and -Z or the indicated side is defined as front, rear, right, left, upper, lower, or front, rear, right, left, upper, and lower, respectively.
In the figure, “•” in “○” means an arrow heading from the back of the page to the front, and “×” in “○” is the front of the page. It means an arrow pointing from the back to the back.
In the following description using the drawings, illustrations other than members necessary for the description are omitted as appropriate for easy understanding.

FIG. 1 is an overall explanatory view of an image forming apparatus according to Embodiment 1 of the present invention.
In FIG. 1, the image forming apparatus U includes an automatic document feeder U1 and an image forming apparatus body U2 that supports the automatic document feeder U1 and has a transparent document reading surface PG at the upper end.
The automatic document feeder U1 includes a document feeding unit TG1 that stores a plurality of documents Gi to be copied, and a document feeding unit TG1 that is fed from the document feeding unit TG1 and passes a document reading position on the document reading surface PG. And a document discharge portion TG2 from which the document Gi conveyed is discharged.
The image forming apparatus main body U2 includes an operation unit UI through which a user inputs an operation command signal for starting an image forming operation, an exposure optical system A, and the like.

Reflected light from a document conveyed on the document reading surface PG by the automatic document feeder U2 or a document manually placed on the document reading surface PG is passed through the exposure optical system A by the solid-state image sensor CCD. It is converted into electrical signals of R (red), G (green), and B (blue).
The image information conversion unit IPS temporarily converts the RGB electrical signals input from the solid-state imaging device CCD into K (black), Y (yellow), M (magenta), and C (cyan) image information. The image information is stored and output to the latent image forming apparatus drive circuit DL as image information for forming a latent image at a predetermined timing.
When the document image is a single color image, so-called monochrome, only K (black) image information is input to the latent image forming device drive circuit DL.
The latent image forming device drive circuit DL has drive circuits (not shown) for the respective colors Y, M, C, and K, and outputs a laser drive signal corresponding to input image information at a predetermined timing. The laser beam is output to a latent image writing laser diode (not shown) of each color of the forming apparatus ROS.

FIG. 2 is an enlarged explanatory view of a main part of the image forming apparatus according to the first embodiment.
The visible image forming devices Uy, Um, Uc, Uk arranged above the latent image forming device ROS are respectively Y (yellow), M (magenta), C (cyan), and K (black). An apparatus for forming a toner image.
Laser beams Ly, Lm, Lc, and Lk as examples of Y, M, C, and K latent image writing lights emitted from the respective laser diodes of the latent image forming apparatus ROS are respectively rotated image carriers PRy and PRm. , PRc, PRk. In the first embodiment, laser beams Ly, Lm, Lc, and Lk having a wavelength of 780 nm are used. However, the wavelength can be changed according to the design or the like.
The Y visible image forming device Uy includes a rotating image carrier PRy, a charger CCy, a developing device Gy, a transfer device T1y, a pre-cleaning corotron 1y as an example of a pre-cleaning static eliminator, an optical static eliminator 2y, and an image. A holder cleaner CLy is provided. In the visible image forming apparatus Uy according to the first exemplary embodiment, the image holding body PRy, the charger CCy, the precleaning corotron 1y, the light static eliminator 2y, and the image holding body cleaner CLy serve as the image holding body device. A detachable body that is detachable from the main body is a so-called unit, and the developing device Gy is also a detachable unit.
The visible image forming apparatuses Um, Uc, Uk of other colors are all configured in the same manner as the Y visible image forming apparatus Uy.

1 and 2, the image carriers PRy, PRm, PRc, and PRk are uniformly charged by their respective chargers CCy, CCm, CCc, and CCk, and then image writing positions Q1y, Q1m, Q1c, At Q1k, an electrostatic latent image is formed on the surface of the laser beam Ly, Lm, Lc, Lk. The electrostatic latent images on the surfaces of the image carriers PRy, PRm, PRc, and PRk are developed into toner images as examples of visible images by the developing devices Gy, Gm, Gc, and Gk in the development regions Q2y, Q2m, Q2c, and Q2k. Is done.
In the image forming apparatus U of the first embodiment, the image carriers PRy, PRm, PRc, and PRk have an outer diameter of 84 mm, and the so-called process speed is set to 420 mm / s. The surfaces of the image carriers PRy, PRm, PRc, and PRk are charged to −700 V by the chargers CCy, CCm, CCc, and CCk, and the image portion irradiated with the laser beams Ly, Lm, Lc, and Lk has a charged potential of − It is set to be 300V. The developing units Gy, Gm, Gc, and Gk contain a two-component developer composed of toner and carrier, and are developed with an interval of 0.3 mm from the image carriers PRy, PRm, PRc, and PRk. The developing roll as an example of the agent holder has a non-rotatable magnet roll and a cylindrical sleeve arranged on the outer periphery of the magnet roll, and has a sleeve diameter of 16 mm and a sleeve rotation speed of 800 mm / s. ing. A developing voltage in which a DC voltage of −500 V and an AC voltage having a frequency of 6 kHz and a peak-to-peak voltage Vpp of 1.5 kV are superimposed is applied to the developing roll. In addition, specific numerical values, such as each voltage and an outer diameter, are examples, and can be changed according to design.

The developed toner image is conveyed to primary transfer regions Q3y, Q3m, Q3c, and Q3k that are in contact with an intermediate transfer belt B as an example of an intermediate transfer member. The primary transfer units T1y, T1m, T1c, and T1k disposed on the back side of the intermediate transfer belt B in the primary transfer regions Q3y, Q3m, Q3c, and Q3k are supplied with a predetermined value from a power supply circuit E controlled by the control unit C. At this timing, a primary transfer voltage having a polarity opposite to the charging polarity of the toner is applied. In the first embodiment, a constant current controlled voltage of +43 μA is applied as the primary transfer voltage to the primary transfer units T1y, T1m, T1c, and T1k.
The toner images on the image carriers PRy to PRk are primarily transferred to the intermediate transfer belt B by the primary transfer units T1y, T1m, T1c, and T1k. The residual toner on the surface of the image carrier PRy, PRm, PRc, PRk after the primary transfer is charged by the pre-cleaning corotrons 1y, 1m, 1c, 1k, so that the charged potential on the surface of the image carrier and the toner The charged polarity is adjusted, and cleaning is performed by the image carrier cleaner CLy, CLm, CLc, CLk. Further, the surfaces of the image carriers PRy, PRm, PRc, and PRk are neutralized by the pre-cleaning corotrons 1y, 1m, 1c, and 1k and the light neutralizers 2y, 2m, 2c, and 2k, and the chargers CCy, CCm, and CCc. , CCk is recharged.

  Above the image carriers PRy to PRk, a belt module BM as an example of an intermediate transfer device that can move up and down and can be pulled out forward is disposed. The belt module BM includes an intermediate transfer belt B as an example of an intermediate transfer member, a belt drive roll Rd as an example of an intermediate transfer member drive member, a tension roll Rt as an example of an intermediate transfer member stretching member, and a meander prevention Belt support roll as an example of an intermediate transfer member support member including a walking roll Rw as an example of a member, an idler roll (free roll) Rf as an example of a driven member, and a backup roll T2a as an example of a secondary transfer region facing member (Rd, Rt, Rw, Rf, T2a) and the primary transfer units T1y, T1m, T1c, T1k. The intermediate transfer belt B is rotatably supported by the belt support rolls (Rd, Rt, Rw, Rf, T2a).

A secondary transfer roll T2b as an example of a secondary transfer member is disposed facing the surface of the intermediate transfer belt B in contact with the backup roll T2a, and a secondary transfer device T2 is configured by the rolls T2a and T2b. ing. Further, a secondary transfer region Q4 is formed in a region where the secondary transfer device T2b and the intermediate transfer belt B face each other.
The single-color or multi-color toner images transferred in succession on the intermediate transfer belt B by the transfer devices T1y, T1m, T1c, and T1k in the primary transfer areas Q3y, Q3m, Q3c, and Q3k are transferred to the secondary transfer area Q4. It is conveyed to.

  Below the latent image forming device ROS, a pair of left and right guide rails GR as an example of a guide member that supports paper feed trays TR1 to TR3 as an example of a paper feed container so as to be able to enter and exit in the front-rear direction (X-axis direction). , GR are provided in three stages. A recording sheet S as an example of a medium accommodated in the paper feed trays TR1 to TR3 is taken out by a pickup roll Rp as an example of a medium takeout member and separated one by one by a separating roll Rs as an example of a medium separating member. The The recording sheet is transported along a sheet transport path SH, which is an example of a medium transport path, by a plurality of transport rolls Ra, which is an example of a medium transport member, and is disposed upstream of the secondary transfer region Q4 in the sheet transport direction. In addition, the image is sent to a registration roll Rr as an example of a transfer region conveyance timing adjusting member. A sheet conveying device (SH + Ra + Rr) is configured by the sheet conveying path SH, the sheet conveying roll Ra, the registration roll Rr, and the like.

The registration roll Rr conveys the recording sheet S to the secondary transfer area Q4 in time with the toner image formed on the intermediate transfer belt B being conveyed to the secondary transfer area Q4. When the recording sheet S passes through the secondary transfer area Q4, the backup roll T2a is grounded, and the secondary transfer unit T2b is charged with toner at a predetermined timing from the power supply circuit E controlled by the control unit C. A secondary transfer voltage having the opposite polarity is applied. At this time, the color toner image on the intermediate transfer belt B is transferred to the recording sheet S by the secondary transfer device T2.
The intermediate transfer belt B after the secondary transfer is cleaned by a belt cleaner CLb as an example of an intermediate transfer body cleaner.

The recording sheet S on which the toner image is secondarily transferred has a fixing region Q5 which is a pressure contact region of a heating roll Fh as an example of a heating fixing member of the fixing device F and a pressure roll Fp as an example of a pressing fixing member. And heated and fixed when passing through the fixing region. The heat-fixed recording sheet S is discharged from a discharge roller Rh as an example of a medium discharge member to a discharge tray TRh as an example of a medium discharge portion.
Note that a release agent for improving the releasability of the recording sheet S from the heating roll is applied to the surface of the heating roll Fh by a release agent application device Fa.

  Above the belt module BM, developer cartridges Ky, Km, Kc as an example of a developer supply container for storing Y (yellow), M (magenta), C (cyan), and K (black) developers. , Kk are arranged. The developer contained in each developer cartridge Ky, Km, Kc, Kk is supplied from the developer supply path (not shown) to each developer Gy according to the consumption of the developer in the developers Gy, Gm, Gc, Gk. , Gm, Gc, Gk.

In FIG. 1, the image forming apparatus U has an upper frame UF and a lower frame LF, and the upper frame UF is located above the latent image forming apparatus ROS and the latent image forming apparatus ROS. Arranged members (image holders PRy, PRm, PRc, PRk, developing devices Gy, Gm, Gc, Gk, belt module BM, etc.) are supported.
The lower frame LF includes a guide rail GR that supports the paper feed trays TR1 to TR3 and the paper feed members that feed paper from the trays TR1 to TR3 (pickup roll Rp, separation roll Rs, sheet conveyance). Roll Ra etc.) is supported.

(Description of image carrier)
FIG. 3 is an explanatory diagram of the image carrier according to the first embodiment of the present invention.
Next, the configuration of the image carriers PRy, PRm, PRc, and PRk according to the first embodiment of the present invention will be described. Since the image carriers PRy, PRm, PRc, and PRk of the respective colors are similarly configured, the Y color Only the image carrier PRy will be described, and detailed descriptions of the other image carriers PRm, PRc, and PRk will be omitted.
In FIG. 3, the image carrier PRy of Example 1 includes a grounded aluminum cylindrical substrate 11. An undercoat layer 12 is formed on the surface of the airframe, and a charge generation layer 13 is formed outside the undercoat layer 12. A charge transport layer 14 is formed on the surface side of the charge generation layer 13, and a protective layer 15 is formed on the surface side of the charge transport layer 14.
Therefore, in the image carrier PRy, when the surface is charged by the charger CCy and irradiated with the laser beam Ly, charges and holes are generated in the charge generation layer 13, and the charge transport layer 14 and the protective layer The charge is transported through the surface 15, the surface charge flows, and the charged potential of the portion irradiated with the laser light Ly is lowered with respect to the portion not irradiated with the laser light Ly.

(Description of image carrier cleaner)
FIG. 4 is an enlarged explanatory view of the main part of the image carrier cleaner, FIG. 4A is an enlarged explanatory view of the main part of the image carrier cleaner of Example 1 of the present invention, and FIG. 4B is an illustration of a conventional image carrier cleaner. It is a principal part expansion explanatory drawing.
Next, the configuration of the image carrier cleaner CLy, CLm, CLc, CLk, the pre-cleaning corotrons 1y, 1m, 1c, 1k, and the photostatic dischargers 2y, 2m, 2c, 2k according to the first embodiment of the present invention will be described. However, since the image carrier cleaners CLy, CLm, CLc, CLk, etc. of the respective colors are configured in the same manner, only the Y color will be described, and a detailed description of the other colors will be omitted.
4A, the image carrier cleaner CLy according to the first embodiment includes a housing 20 as an example of a cleaning container, and a rotating cleaning member disposed in the housing 20 so as to face the image carrier PRy. As an example, a cleaning roll 21 is rotatably supported. The cleaning roll 21 according to the first embodiment is configured by a rotationally driven roll having an outer diameter of 12 mm, and is set to rotate in the same direction at a position facing the image carrier PRy.
The cleaning roll 21 of the embodiment includes a shaft 21a having a diameter of 6 mm, an elastic layer 21b fixed around the shaft 21a, and a fiber layer (surface layer) 21c having a layer thickness of 900 μm coated on the surface of the elastic layer. .

The shaft 21a can be made of, for example, a metal such as iron or SUS, and the elastic layer 21b can be made of, for example, conductive urethane formed of a conductive material such as carbon black, NBR, SBR, EPDM, or the like. The cylindrical roll can be used.
Moreover, the fiber layer 21c can use the nonwoven fabric which consists of a conductive fiber, and the thing formed into the cloth form by knitting or weaving a conductive fiber. Here, as the conductive fiber, for example, a split fiber of nylon conductive yarn in which carbon black is dispersed (KB Seiren Co., Ltd.) having a fiber thickness of 0.5 denier (248T / 450F) is used. be able to. Thus, by using ultrafine conductive fibers, the surface area of the fiber layer 21c can be increased, so that a large amount of toner can be held and the cleaning performance can be improved. In this case, from the viewpoint of toner retention and cleaning properties, the thickness of the conductive fiber is preferably 2 denier (diameter about 15 μm) or less, more preferably 1 denier (diameter about 11 μm) or less. In addition, examples of the nonwoven fabric include a dry nonwoven fabric, a sponge band, a wet nonwoven fabric, and the like. In this embodiment, a dry nonwoven fabric is used. Specifically, a dry nonwoven fabric is formed by forming fibers with a fiber length of several centimeters into thin sheets with a card or an air random machine, and stacking several sheets as necessary. The joint is formed by entanglement with a high-pressure fine water stream.
A residual toner removal voltage having a polarity opposite to the charging polarity of the residual toner is applied to the cleaning roll 21 of the first embodiment. Accordingly, an electric field is generated in which the residual toner is electrostatically moved from the surface of the image carrier PRy to the cleaning roll 21 side, and the residual toner is removed from the image carrier PRy. Further, the discharge product, paper dust, dust and other deposits adhering to the image carrier PRy are also removed by the cleaning roll 21.

A recovery roll 22 is disposed on the cleaning roll 21 as an example of a recovery member for recovering the developer removed by the cleaning roll 21 so as to be in contact with and opposed to the recovery roll 22. A scraper 23 is disposed as an example of a scraping member that scrapes off the toner.
The collection roll 22 is made of, for example, a phenol resin having a resistance value adjusted by dispersing carbon black. It is also possible to use a metal material such as iron or SUS, and it is also possible to form a coating such as a fluororesin in order to facilitate the contact with the scraper 23 or improve the toner releasability.
The recovery roll 22 is applied with a residual toner recovery voltage that generates an electric field in which the toner on the surface of the cleaning roll 21 moves electrostatically toward the recovery roll 22.

A cleaning blade 24 as an example of a scraping member that scrapes residual toner from the surface of the image carrier PRy is disposed on the downstream side of the cleaning roller 21 in the rotation direction of the image carrier PRy. The cleaning blade 24 of Example 1 is made of an elastic rubber having a 100% modulus of 6.2 MPa to 19.6 MPa. The 100% modulus is measured by a measurement method based on JIS K 6301 (vulcanized rubber physical test method) and indicates a stress at 100% elongation in an environment of 23 ° C.
The toner recovered from the cleaning roll 21 to the recovery roll 22 and scraped off by the scraper 23 and the toner scraped off by the cleaning blade 24 are transported by a waste toner transport auger 26 as an example of a waste developer transport member. It is collected in a waste developer collecting container (not shown).
The image bearing member cleaner CLy according to the first exemplary embodiment is configured by the members denoted by the reference numerals 21 to 26.

(Explanation of charger)
4A, the charger CCy of Example 1 is configured by a contact-type scorotron, and a charging voltage for charging the surface of the image carrier PRy is applied to the charger CCy from the charging power supply circuit Eb. . In the first embodiment, the charger CCy includes a scorotron having a shield 30y as an example of a frame, a discharge wire 31y as an example of a discharge unit, and a grid 32y as an example of a discharge uniformizing member. In order to charge the surface of the image carrier PRy to −700V, a grid voltage of −750V is applied to the grid 32y.
In Example 1, the pre-cleaning corotron 1y is also a contact-type corotron, the current value of the discharge wire 36y is −400 μA, and the potential of the image carrier PRy after passing through the pre-cleaning corotron 1y is It is set to be −600V.

(Operation of Example 1)
In the image forming apparatus U of Example 1 having the above-described configuration requirements, the toner images formed on the surfaces of the image carriers PRy to PRk are transferred and fixed onto the recording sheet S via the intermediate transfer belt B. The residual toner adhering to the surfaces of the image carriers PRy to PRk after the primary transfer is adjusted in charge and the like by the pre-cleaning corotrons 1y to 1k. The residual toner whose charge is adjusted is removed by the cleaning roll 21 and the cleaning blade 24. At this time, the surfaces of the image carriers PRy to PRk are worn by rubbing against the cleaning roll 21, the cleaning blade 24, and the like. The image carriers PRy to PRk of Example 1 are less worn by the protective layer 15 on the surface and have a longer life, and if the wear is too little, the surfaces of the image carriers PRy to PRk are stained with toner over time. Since image quality deterioration such as image flow may occur, the cleaning roll 21 and the cleaning blade 24 cause rubbing and wear necessary to suppress image flow and the like.

(Experimental example)
Next, an experiment was performed to determine the relationship between the position where the light neutralizers 2y to 2k are disposed and the necessary current value required for the chargers CCy to CCk to charge the surface of the image carrier to a charging voltage.
In the experiment, the positions at which the light neutralizers 2y to 2k are disposed are the positions of the first embodiment and the conventional image forming apparatus shown in FIG. 4B, that is, along the rotation direction of the image carriers PRy to PRk. When the photostatic discharger is arranged between the image carrier cleaner CLy to CLk and the chargers CCy to CCk, the scorotron CCy required to charge the surface of the image carrier PRy to PRk to −700V. The current value of CCk discharge wire 31 was measured.
In the experimental example, the image carrier B of the following specific example 1 is used as the image carrier PRy to PRk with the protective layer 15, and the following comparative example is used as the image carrier PRy to PRk without the protective layer 15. 1 image carrier A was used.

(Comparative Example 1)
The method for producing the image carrier of Comparative Example 1 is exemplified below.
100 parts by weight of zinc oxide (SMZ-017N, manufactured by Teika Co., Ltd.) was stirred and mixed with 500 parts by weight of toluene, and 2 parts by weight of a silane coupling agent (A1100, manufactured by Nihon Unicar Co., Ltd.) was added and stirred for 5 hours. Thereafter, toluene was distilled off under reduced pressure and baked at 120 ° C. for 2 hours. As a result of analyzing the obtained surface-treated zinc oxide by fluorescent X-ray, the Si element strength was 1.8 × 10 ⁻⁴ of the zinc element strength. 35 parts by weight of zinc oxide subjected to the surface treatment, 15 parts by weight of blocked isocyanate (Sumijoule 3175, manufactured by Sumitomo Bayern Urethane) as a curing agent, and 6 parts by weight of butyral resin (BM-1, manufactured by Sekisui Chemical Co., Ltd.) And 44 parts by weight of methyl ethyl ketone were mixed and dispersed for 2 hours in a sand mill using glass beads having a diameter of 1 mm to obtain a dispersion. As a catalyst, 0.005 part by weight of dioctyltin dilaurate and 17 parts by weight of silicone fine particles (Tospearl 130, manufactured by GE Toshiba Silicone Godo Kaisha) were added to the resulting dispersion to obtain an undercoat layer coating solution.

This coating solution was applied onto the aluminum substrate 11 by a dip coating method, followed by drying and curing at 160 ° C. for 100 minutes to obtain an undercoat layer 12 having a thickness of 20 μm. The surface roughness was measured using a surface roughness shape measuring instrument (Surfcom 570A, manufactured by Tokyo Seimitsu Co., Ltd.) at a measurement distance of 2.5 mm and a scanning speed of 0.3 mm / sec. 24.
Next, on this aluminum substrate, the Bragg angles (2θ ± 0.2 °) in the X-ray diffraction spectrum are strongly diffracted to 7.5 °, 9.9 °, 12.5 °, 16.3 °, 18.6 °, 25.1 °, 28.3 °. After mixing 1 part hydroxygallium phthalocyanine with a peak, 1 part polyvinyl butyral (ESREC BM-S, Sekisui Chemical) and 100 parts n-butyl acetate and treating with glass beads for 1 hour and dispersing. The resulting coating solution was dip-coated on the undercoat layer and dried by heating at 100 ° C. for 10 minutes to form a charge generation layer 13 having a thickness of about 0.15 μm.
Next, a coating solution prepared by dissolving 2 parts of the benzidine compound of Chemical Formula 1 below and 3 parts of the polymer compound of Chemical Formula 2 below (viscosity average molecular weight 39,000) in 20 parts of chlorobenzene is applied onto the charge generation layer by a dip coating method. This was applied and heated at 110 ° C. for 40 minutes to form a charge transport layer 14 having a thickness of 22 μm. This is referred to as an image carrier A.

(Specific example 1)
The image carrier of Example 1 is a ring type dip coating on the surface of the image carrier A of Comparative Example 1 on the charge transport layer 14 with a coating solution in which the following constituent material B is dissolved in 75 parts of butanol. After coating by the method and air-drying at room temperature for 30 minutes, the surface layer 15 having a film thickness of about 5 μm was formed by curing by heating at 130 ° C. for 1 hour. This is referred to as an image carrier B. The experimental results are shown in FIG.
Component material B
Compound of the following chemical formula 13 parts by mass phenol resin (Gunei Chemical PL4852) 13 parts by mass repellent 0.1 parts by mass

FIG. 5 is an explanatory diagram of the experimental results of Example 1, and FIG. 5A is a diagram of the scorotron wire in the case of Example 1 and in the case where the light static eliminator is disposed at the conventional position in the image carrier having the protective layer. FIG. 5B is a graph in which the vertical axis represents the required current value of the scorotron with respect to the experimental result of FIG. 5A, and FIG. 5C is the case of Example 1 in the image carrier having no protective layer. And FIG. 5D is a graph in which the required current value of the scorotron is plotted on the vertical axis for the experimental result of FIG. 5C. It is.
As shown in FIG. 5A and FIG. 5B, as in the first embodiment, by disposing the optical static eliminators 2y to 2k on the upstream side in the rotation direction of the image carriers PRy to PRk of the image carrier cleaners CLy to CLk, The required current value is kept low as compared with the case of using a conventional light neutralizer, so-called erase lamp. Further, as shown in FIGS. 5C and 5D, when the protective layer 15 is not provided on the image carriers PRy to PRk, the necessary current value is not so large, but is necessary by providing the protective layer 15. While the current value is increased, the light neutralizers 2y to 2k are arranged at the positions of the first embodiment, so that the current value is the same as in the case where the conventional protective layer 15 is not provided.

The reason why the required current values at the discharge wires 31y to 31k of the chargers CCy to CCk are high when the image carriers PRy to PRk provided with the surface layer 15 are neutralized by the light neutralizers 2y to 2k at the conventional positions. This is considered to be based on the following principle.
When the image carriers PRy to PRk provided with the protective layer 15 are irradiated with light at the conventional positions by the light neutralizers 2y to 2k, they are generated in the charge generation layer 13 of the image carriers PRy to PRk and moved to the surface layer 15. The so-called holes, so-called holes, are trapped at the trap sites in the surface layer 15. After that, when charged by the chargers CCy to CCk constituted by the scorotron, although it is sufficiently charged immediately below the scorotron, a high electric field is applied to the image carriers PRy to PRk, so the trapped holes are released, The potential is rapidly attenuated, and the potential in the development areas Q2y to Q2k is lowered. That is, dark decay becomes large.

  Therefore, in the conventional position, as shown in FIGS. 5A and 5C, an abnormally high current value is required to charge to a predetermined charging potential as compared with the case where the protective layer 15 is not provided. Considered. When the current value is increased, the maximum voltage cannot be satisfied from the viewpoint of safety determined from the insulation distance between the discharge wire 31y and the shield 30y, between the discharge wire 31y and the grid 32y, and when the maximum voltage is to be satisfied, the discharge wire 31y There is a problem that the current value has to be lowered and the necessary charging potential cannot be sold. That is, a desired potential cannot be obtained within the safe voltage range. For this reason, it may be difficult to use the image carriers PRy to PRk having the protective film 15 particularly in a high-speed machine that requires a large current and has a process speed of 400 mm / s or higher.

  On the other hand, by arranging the photostatic dischargers 2y to 2k at the positions shown in the first embodiment, holes generated when performing the photostatic discharge with the photostatic dischargers 2y to 2k are trapped in the bulk trap of the protective layer 15. End up. However, in the first embodiment, the distance from the optical static eliminators 2y to 2k to the chargers CCy to CCk is longer than that of the conventional case where it is disposed immediately upstream of the charger, and it takes time. It is presumed that the time for opening is secured and that dark decay is prevented. For this reason, it is charged to a sufficient potential with a current value almost the same as the case where the protective layer 15 is not provided.

(Specific example 2)
The image carrier of Example 2 was prepared by adding 5 parts of methyl alcohol and 0.3 part of ion exchange resin (Amberlyst 15E) to the constituent material C shown below on the surface of the image carrier A of Comparative Example 1 and stirring at room temperature. Thus, the protecting group was exchanged for 24 hours.
Component material C
Compound of the following chemical formula 2 2 parts Compound of the chemical formula 5 1 part Colloidal silica 0.3 part
Me (MeO) 2-Si- (CH2) 4-Si-Me (OMe) 2 2 parts
(Heptadecafluoro-1,1,2,2-tetrahydrodecyl) methyldimethoxysilane 0.1 part Hexamethylcyclotrisiloxane 0.3 part
ZX-022 (Fuji Kasei Kogyo Co., Ltd.) 0.25 parts

Thereafter, 10 parts of n-butanol and 0.25 part of distilled water were added and hydrolyzed for 5 minutes.
0.1 parts of aluminum trisacetylacetonate (Al (aqaq) 3), 0.1 part of acetylacetone, 3,5-di-t-butyl-4 are obtained by filtering and separating the ion exchange resin from the hydrolyzed product. -0.4 part of hydroxytoluene (BHT) was added, and this coating solution was applied onto the charge transport layer 14 by a ring-type dip coating method, air-dried at room temperature for 30 minutes, and then heat-treated at 130 ° C for 1 hour. Then, a surface layer 15 of a siloxane resin having a film thickness of about 3 μm and a crosslinkable resin was formed. This is designated as an image carrier C.
Even in the case of the specific example 2, as in the case of the specific example 1, it was possible to sufficiently charge while suppressing the necessary current value in the chargers CCy to CCk, and it was possible to perform good image formation.

FIG. 6 is an explanatory diagram of a main part of the image forming apparatus according to the second embodiment of the invention, and corresponds to FIG. 2 according to the first embodiment.
In the description of the second embodiment, components corresponding to those of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
The second embodiment is different from the first embodiment in the following points, but is configured in the same manner as the first embodiment in other points.
In FIG. 6, in the image forming apparatus U according to the second embodiment, the positions of the light neutralizers 2 y to 2 k are aligned with the primary transfer units T1 y to T1 k along the rotation direction of the image carriers PRy to PRk, that is, the primary transfer region. The configuration is the same as that of the first embodiment except that it is arranged downstream of Q3y to Q3k and upstream of the pre-cleaning corotrons 1y to 1k.

(Operation of Example 2)
In the image forming apparatus U of Example 2 having the above-described configuration, an experiment for measuring necessary current values with the discharge wires 31y to 31k was performed in the same manner as in Example 1.
(Experimental result)
FIG. 7 is an explanatory diagram of the experimental results of Example 2, and FIG. 7A shows the necessity of the scorotron wire in the case where the position of the light static eliminator is the case of Example 1 and Example 2 in the image carrier having the protective layer. FIG. 7B is a graph in which the scorotron required current value is plotted on the vertical axis for the experimental result of FIG. 7A.

As shown in FIG. 7, in the second embodiment, the necessary current value is further reduced as compared with the first embodiment.
This is because, in the second embodiment, compared to the first embodiment, the distance from the photostatic discharger 2y-2k to the photocharger CCy-CCk is further increased. Furthermore, it is estimated that the current value is greatly reduced by another action. That is, when the light static eliminators 2y to 2k are arranged at the positions in the case of the first embodiment, when the surface of the image carrier PRy to PRk enters the light static elimination region irradiated with light by the light static eliminators 2y to 2k, The pre-cleaning corotrons 1y to 1k on the upstream side of the light neutralizers 2y to 2k are discharged to charge the surface. Therefore, the surface is charged into -600V by the pre-cleaning corotrons 1y to 1k, and enters the light static eliminators 2y to 2k.

On the other hand, in Example 2, the potential immediately after the primary transfer is about −50 V to −200 V inrush potential to the photostatic dischargers 2 y to 2 k, which is a potential having a lower absolute value than that in Example 1. It has become. Therefore, when the photostatic dischargers 2y to 2k are subjected to photostatic discharge, the number of holes generated in the charge generation layer 13 of the image carriers PRy to PRk and moving to erase the surface charge is reduced, and thus trapped. It is estimated that there are few holes and dark decay is further reduced. As a result, in the second embodiment, the current value required for the chargers CCy to CCk is further reduced as compared with the first embodiment.
In Example 2, since the surface is charged by the pre-cleaning corotrons 1y to 1k after being subjected to the light static elimination by the light static eliminators 2y to 2k, the pre-cleaning corotrons 1y to 1k can be charged without uneven charging. Is not high, that is, when the so-called potential leveling capability is not high, it is desirable that the pre-cleaning corotrons 1y to 1k are constituted by scorotrons having high potential leveling capability instead of corotrons. As a result, the potential at the time of entry of the surfaces of the image carriers PRy to PRk into the chargers CCy to CCk becomes uniform, and charging unevenness in the chargers CCy to CCk is reduced.

FIG. 8 is an explanatory diagram of a main part of the image forming apparatus according to the third embodiment of the invention, and corresponds to FIG. 2 according to the first embodiment.
In the description of the third embodiment, components corresponding to those of the first and second embodiments are denoted by the same reference numerals, and detailed description thereof is omitted.
The third embodiment is different from the first and second embodiments in the following points, but is configured in the same manner as the first and second embodiments in other points.
In FIG. 8, in the image forming apparatus U according to the third embodiment, the rotation directions of the first light neutralizers 2y to 2k arranged at the same positions as in the first embodiment and the image carriers PRy to PRk as in the conventional case. 2 with respect to the image carrier cleaners CLy to CLk and the second photostatic dischargers 41y to 41k arranged at positions upstream of the chargers CCy to CCk.

(Operation of Example 3)
In the image forming apparatus U according to the third embodiment having the above-described configuration, the holes trapped in the bulk of the protective layer 15 by the light neutralization by the first light neutralizers 2y to 2k are sufficiently released because the release time is long. In addition, the electric potential after the photostatic elimination is neutralized to a sufficiently low value of about 0 to -50V. Therefore, there is almost no generation of holes even if the second static eliminators 41y to 41k are used for further static elimination thereafter. Therefore, the image forming apparatus U of the third embodiment is also charged by the chargers CCy to CCk with the same current value as the necessary current value of the discharge wire 31y of the first embodiment. If there is a large amount of residual toner and the surface of the image carrier PRy to PRk is shielded by the residual toner that has adhered, even if a portion that cannot be sufficiently neutralized is generated, it is discharged by the second photostatic dischargers 41y to 41k. The chargers CCy to CCk are reliably charged without uneven charging.

(Example of change)
As mentioned above, although the Example of this invention was explained in full detail, this invention is not limited to the said Example, A various change is performed within the range of the summary of this invention described in the claim. It is possible. Modification examples (H01) to (H06) of the present invention are exemplified below.
(H01) In the above-described embodiment, the copying machine as the image forming apparatus has been illustrated. However, the present invention is not limited to this, and a FAX, a printer, or a multifunction machine having all or a plurality of functions may be used. Further, the present invention is not limited to a multicolor image forming apparatus, and can be applied to a monochromatic, so-called monochrome image forming apparatus.

(H02) Specific numerical values such as materials, potentials, and speeds of the members exemplified in the above embodiments can be arbitrarily changed according to design, specifications, and the like.
(H03) In the embodiment, the configuration of the image carrier is not limited to the configuration illustrated in the embodiment, and any configuration can be adopted. For example, the undercoat layer 12 can be omitted, and any configuration such as adding a conductive layer between the undercoat layer 12 and the substrate 11 can be employed.
(H04) In the above embodiment, the cleaning roller using a nonwoven fabric or the like is used. However, the present invention is not limited to this, and any image carrier rotating cleaning member such as a cleaning brush can be used. In the above embodiment, a non-contact corotron and a scorotron are used for the charger and the static eliminator (pre-cleaning corotron). However, the invention is not limited to the above. For example, the charger is a contact-type charging roll. Or using a brush roll in contact with a static eliminator, the same effect is exhibited.

(H05) In the above embodiment, the image carriers PRy to PRk are arranged in the order of Y, M, C, and K from the upstream side with respect to the rotation direction of the intermediate transfer belt B. Can be arbitrarily changed. In addition, the intermediate transfer belt B is not provided, and the image may be transferred directly from the image carriers PRy to PRk to the medium, or may have an intermediate transfer drum. The number of the image carriers PRy to PRk is four, that is, not limited to four colors, but may be three colors or less or five colors or more.
(H06) In the above embodiment, the image carrier device is exemplified by the image carrier PRy, the charger CCy, the pre-cleaning corotron 1y, the light static eliminator 2y, and the image carrier cleaner CLy. However, the present invention is not limited to this, and any member may be formed as a separate unit, or an image holding device having a developing device Gy and other members may be used.

FIG. 1 is an overall explanatory view of an image forming apparatus according to Embodiment 1 of the present invention. FIG. 2 is an enlarged explanatory view of a main part of the image forming apparatus according to the first embodiment. FIG. 3 is an explanatory diagram of the image carrier according to the first embodiment of the present invention. FIG. 4 is an enlarged explanatory view of the main part of the image carrier cleaner, FIG. 4A is an enlarged explanatory view of the main part of the image carrier cleaner of Example 1 of the present invention, and FIG. 4B is an illustration of a conventional image carrier cleaner. It is a principal part expansion explanatory drawing. FIG. 5 is an explanatory diagram of the experimental results of Example 1, and FIG. 5A is a diagram of the scorotron wire in the case of Example 1 and in the case where the light static eliminator is disposed at the conventional position in the image carrier having the protective layer. FIG. 5B is a graph in which the vertical axis represents the required current value of the scorotron with respect to the experimental result of FIG. 5A, and FIG. 5C is the case of Example 1 in the image carrier having no protective layer. And FIG. 5D is a graph in which the required current value of the scorotron is plotted on the vertical axis for the experimental result of FIG. 5C. It is. FIG. 6 is an explanatory diagram of a main part of the image forming apparatus according to the second embodiment of the present invention, and corresponds to FIG. 2 according to the first embodiment. FIG. 7 is an explanatory diagram of the experimental results of Example 2, and FIG. 7A shows the necessity of the scorotron wire in the case where the position of the light static eliminator is the case of Example 1 and Example 2 in the image carrier having the protective layer. FIG. 7B is a graph in which the scorotron required current value is plotted on the vertical axis for the experimental result of FIG. 7A. FIG. 8 is an explanatory diagram of a main part of the image forming apparatus according to the third embodiment of the present invention, and corresponds to FIG. 2 according to the first embodiment.

Explanation of symbols

1y, 1m, 1c, 1k ... neutralizer before cleaning,
2y, 2m, 2c, 2k ... optical static eliminator,
11 ... Substrate,
13 ... charge generation layer,
14 ... charge transport layer,
15 ... Protective layer,
41y, 41m, 41c, 41k ... second optical static eliminator,
CCy, CCm, CCc, CCk ... charger,
CLy, CLm, CLc, CLk ... Image carrier cleaner,
Gy, Gm, Gc, Gk ... developer,
PRy, PRm, PRc, PRk ... Image carrier,
ROS ... latent image forming device,
T1y, T1m, T1c, T1k ... transfer device,
U: Image forming apparatus.

Claims (9)

A rotating image carrier having a conductive substrate, a charge generation layer for generating charges, a charge transport layer for transporting charges generated in the charge generation layer, and a protective layer formed on the surface and protecting the interior; ,
A charger for charging the surface of the image carrier;
An image carrier cleaner for cleaning the surface of the image carrier that has passed through a transfer region to which a toner image formed on the charged surface is transferred;
A non-contact discharge type pre-cleaning static eliminator disposed on the downstream side of the transfer region and the upstream side of the image carrier cleaner with respect to the rotation direction of the image carrier, and applying charge to the surface of the image carrier;
An optical static eliminator that is disposed downstream of the transfer region and upstream of the image carrier cleaner with respect to the image carrier rotation direction, and irradiates the surface of the image carrier with static elimination light;
An image carrier apparatus comprising: The optical static eliminator disposed on the downstream side of the pre-cleaning static eliminator and the upstream side of the image carrier cleaner with respect to the image carrier rotational direction;
The image carrier apparatus according to claim 1, further comprising: The light static eliminator disposed downstream of the transfer region and upstream of the pre-cleaning static eliminator with respect to the image carrier rotation direction;
The image carrier apparatus according to claim 1, further comprising: The static eliminator before cleaning, comprising: a discharge unit for generating electric charge; and a discharge uniformizing member for uniformly charging the surface of the image carrier by the electric charge generated in the discharge unit;
The image carrier apparatus according to claim 3, further comprising: A second light static eliminator disposed downstream of the image carrier cleaner and upstream of the charger with respect to the image carrier rotation direction;
The image carrier apparatus according to claim 1, further comprising: The protective layer having a crosslinked structure containing a charge transporting material having at least one reactive group that forms a crosslinked structure with a crosslinkable resin;
The image carrier apparatus according to claim 1, further comprising:   The image carrier apparatus according to claim 6, wherein the crosslinkable resin is a phenol derivative.   The image carrier apparatus according to claim 6, wherein the crosslinkable resin is a siloxane-based resin. An image carrier device according to any one of claims 1 to 8,
A non-contact discharge type charger for charging the surface of the image carrier;
A latent image forming apparatus that forms an electrostatic latent image on the surface of the image carrier charged by the charger;
A developing device for developing the electrostatic latent image formed on the surface of the image carrier;
A transfer device for transferring the toner image on the surface of the image carrier;
An image forming apparatus comprising:

Images