JP2011043561A - Image carrier and image forming apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which is allowed to reduce parts used for the image forming apparatus, to reduce a price and a weight of the image forming apparatus and to simplify image forming processes. <P>SOLUTION: The image carrier used for the image forming apparatus is characterized in that a charging body layer on the outer circumferential surface of the image carrier is formed of a resin having a volume resistance of 10<SP>15</SP>Ωcm or more and a Rockwell M hardness of 70° or more. The image forming apparatus using the image carrier is also provided. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image carrier having a charged body layer and an image forming apparatus using the image carrier, and more particularly to an image forming apparatus used in an on-demand printing apparatus such as a printer, a facsimile machine, and a copying machine.

  Among on-demand printing apparatuses, electrophotographic printing apparatuses have been widely used because they have advantages such as a high printing speed and a relatively small influence on the image quality of the material of the recording medium.

  In an image forming apparatus used in such an electrophotographic printing apparatus, for example, as shown in FIG. 7, a photosensitive member 1 ′ as an image carrier is uniformly charged to a negative potential by a charger 19. Thereafter, the photosensitive member 1 ′ is exposed by the exposure means 20 such as a laser oscillation scanning device, and an electrostatic latent image is formed on the photosensitive member 1 ′. Further, a negative developer 7 in the developer container 6 is applied to a developing roller 8 made of a conductive elastic body by a developer supply roller 9 made of a conductive sponge roller or the like, and the developer is applied to the developing roller 8. 7 is carried. Thereafter, the developer regulating blade 10 regulates the developer 7 on the developing roller 8 to form a thin developer layer.

Then, by the rotation of the developing roller 8, the developer 7 on the developing roller 8 comes into contact with the photoreceptor 1 'on which the electrostatic image is formed, and the developer 7 is a portion on which the electrostatic image is formed on the photoreceptor 1'. The electrostatic latent image is developed and visualized (see Patent Documents 1 and 2).
Further, when the visualized image is printed on a recording medium such as plain paper, as shown in FIG. 7, the recording medium 12 such as plain paper conveyed by the recording medium supply device 11 is a photoreceptor 1 ′. Then, the developer 7 is transferred to the transfer portion including the transfer roller 13 and transferred from the photoreceptor 1 ′ toward the transfer roller 13, and is transferred onto the recording medium 12. Then, the recording medium 12 is conveyed to the fixing device 14 where the developer 7 is fixed on the recording medium 12 and printing is completed.

In addition, as an image forming apparatus used in an electrophotographic printing apparatus, there is an image forming apparatus having an electric field curtain device (see Patent Documents 3 to 5).
In an image forming apparatus having this electric field curtain device, for example, as described in Patent Document 5, a photoconductor as an image carrier is uniformly charged to a positive potential by a charger, and then laser oscillation scanning is performed. The photosensitive member is exposed by exposure means such as an apparatus, and an electrostatic latent image is formed on the photosensitive member.

The image forming apparatus of the electrophotographic printing apparatus differs depending on the image forming apparatus, but the image bearing member is a photosensitive member, a laser oscillation scanning device, a charger and its power supply, a developing roller, a developer supply roller, a developer. It includes a large number of parts such as a regulation blade and an electric field curtain device, and there is a problem that the price and weight of the image forming apparatus are high. In particular, the photosensitive member, the laser oscillation scanning device, and the like, which are image carriers, are precise and expensive components, which is one of the causes of increasing the price of the image forming device and, consequently, the printing device.
Further, the electrophotographic printing apparatus has a problem that the image forming process is complicated such as charging, exposure, development, transfer, and fixing.

Therefore, as an image forming apparatus capable of reducing the number of parts and reducing the price and weight, an inexpensive charging device such as a needle electrode and a writing electrode is used on the surface of the image carrier without using a laser oscillation scanning device. There is an image forming apparatus for writing an electrostatic latent image (see Patent Documents 6 and 7).
For example, an image forming apparatus described in Patent Document 6 writes an electrostatic latent image on an image carrier having an insulating inorganic glass layer on the surface using a needle electrode. The forming apparatus uses a writing electrode on an image carrier made of a conductive material such as aluminum, and a grounded base material and an insulating charged body layer formed on the outer periphery of the base material. An electrostatic latent image is written.

Japanese Patent No. 3381975 Japanese Patent Laid-Open No. 7-234484 Japanese Patent Laid-Open No. 63-13068 Japanese Patent Publication No. 5-31146 JP 2008-52034 A Japanese Examined Patent Publication No. 63-45104 JP 2002-172814 A

  However, in the image carrier having the insulating inorganic glass layer on the outer peripheral surface of the base material described in Patent Document 6, the inorganic glass layer has extremely good physical adsorption water characteristics, so that moisture is present on the surface of the inorganic glass. There is a problem in that it is adsorbed well, and the adsorbed moisture increases the electrical conductivity of the glass surface, and the charged charge of the image carrier leaks, reducing the resolution of the image.

Further, in the image carrier composed of an electrically charged charged body layer formed on the outer peripheral surface of a conductive base material such as aluminum described in Patent Document 7, specific materials for the charged body layer are disclosed. Absent. If an inorganic glass layer is formed as the charged body layer, the same problem as in Patent Document 6 occurs.
It is also conceivable to use a resin as the charged body layer. For example, a resin having a low volume resistance such as a formalin resin, a melamine resin, a urea resin, a phenol resin, an epoxy resin, a polyvinyl butyral resin, and a polyamide resin has a high resolution. There is a problem that an image cannot be obtained. For example, a resin having low hardness such as polyethylene resin, polypropylene resin, or polyethylene terephthalate resin has insufficient abrasion resistance, and a defect such as a scratch occurs in the image as the number of printed sheets increases. There is a problem.

  Therefore, the present invention has been intensively studied in view of the above-described circumstances, and provides an image carrier having high volume resistance and hardness as an image carrier, thereby providing a component used in an image forming apparatus. An object of the present invention is to provide an image forming apparatus that can reduce the price and weight of the image forming apparatus, simplify the image forming process, and obtain a high-resolution image.

  As a result of intensive studies to achieve the above object, the present inventor has found that the charged body layer on the outer peripheral surface of the image carrier is formed of a resin having a predetermined volume resistance and Rockwell M hardness. It has been found that the above problems can be solved by adopting a body. The present invention has been completed based on such findings.

That is, the present invention
(1) An image carrier used in an image forming apparatus, wherein a charged body layer on an outer peripheral surface of the image carrier is formed of a resin having a volume resistance of 10 ¹⁵ Ωcm or more and a Rockwell M hardness of 70 degrees or more. Image carrier,
(2) The image bearing member according to (1) above, wherein the charged body layer is formed on the outer peripheral surface of the substrate.
(3) The image bearing member according to (2), wherein the substrate is a conductive substrate,
(4) The image carrier according to any one of (1) to (3), wherein the image carrier is a cylinder.
(5) The image carrier according to any one of (1) to (4) above, a charging device for forming an electrostatic latent image on a charged body layer of the image carrier, and a developer on the charged body layer. An image forming apparatus having a developing roller for transferring, a developer supplying roller for attaching the developer to the developing roller, and a developer regulating blade for regulating the developer on the developing roller;
(6) The image carrier according to any one of the above (1) to (4), a charging device and a developer for forming an electrostatic latent image on a charged body layer of the image carrier, on the charged body layer An image forming apparatus having an electric field curtain device for transition;
Is to provide.

  If the image carrier of the present invention is used, the number of parts used in the image forming apparatus can be reduced. As a result, the price and weight of the image forming apparatus can be reduced, the image forming process can be simplified, and a high resolution image can be obtained. The resulting image forming apparatus can be obtained.

It is a perspective view showing an example of the configuration of the image carrier of the present invention. It is a perspective view which shows the other structural example of the image carrier of this invention. FIG. 3 is a schematic diagram illustrating a configuration example when printing is performed using the image forming apparatus of the present invention. FIG. 4 is a schematic diagram illustrating a configuration example when color printing is performed using the image forming apparatus of the present invention. It is a schematic diagram which shows the other structural example in the case of performing color printing using the image forming apparatus of this invention. It is a schematic diagram which shows the other structural example of the image forming apparatus of this invention. FIG. 10 is a schematic diagram illustrating a configuration example in a case where printing is performed using a conventional image forming apparatus.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Image carrier)
The image carrier used in the image forming apparatus of the present invention has a charged body layer formed on the outer peripheral surface of the image carrier, and even if the entire image carrier is a charged body layer, A charged body layer may be formed on the outer peripheral surface.
FIG. 1 is a perspective view showing a configuration example of an image carrier according to an embodiment of the present invention. In FIG. 1, 1 is an image carrier, and 2 is a charged body layer. In FIG. 1, a charged body layer 2 is formed of a cylindrical resin, and the charged body layer 2 is an image carrier 1 as it is. Such an image carrier 1 (charged body layer 2) can be produced by extrusion molding of a resin or the like.
In FIG. 1, the image carrier 1 is a cylindrical image carrier. However, the image carrier 1 is not limited to a cylindrical image carrier, and may be a belt-like image carrier.

The charged body layer 2 is formed of a resin having a volume resistance of 10 ¹⁵ Ωcm or more and a Rockwell M hardness of 70 degrees or more.
If the volume resistance is less than 10 ¹⁵ Ωcm, charge leakage occurs when forming an electrostatic latent image, the contrast of the region adjacent to the latent image becomes unclear, and it becomes difficult to obtain a high-resolution image. JIS K6911 can be used as a method for measuring volume resistance. In addition, when the Rockwell M hardness is less than 70 degrees, the abrasion resistance is insufficient, and as the number of printed sheets increases, the charged body layer is damaged due to contact between the charged body layer and the charging device or recording medium described later. This is because image defects are likely to occur.
The volume resistance is more preferably 10 ¹⁶ Ωcm or more. Further, the Rockwell M hardness is more preferably 80 degrees or more.

Here, the reason why the Rockwell M hardness is adopted as the standard of the hardness of the resin is that it is suitable for measurement in a high hardness region having excellent abrasion resistance as compared with the Rockwell R hardness and the Shore hardness.
Examples of the resin having such volume resistance and Rockwell M hardness include polycarbonate resin and polyacetal resin. In particular, polycarbonate can be easily dissolved in a solvent to prepare a coating material. Therefore, it is preferable because the charged body layer 2 can be easily manufactured.
These resins may be mixed with a charge control agent such as a salicylic acid metal complex in order to adjust the chargeability.
When the charged body layer 2 is used as it is as the image carrier 1, the thickness of the image carrier 1 (charged body layer 2) is preferably 0.5 to 20 mm, more preferably 1 to 10 mm, and further preferably 1 to 3 mm. . This is because within this range, the potential can be maintained, the strength can be maintained, and the weight can be reduced.

FIG. 2 is a perspective view showing another configuration example of the image carrier of the present invention. In FIG. 2, 1 is an image carrier, 2 is a charged body layer, and 3 is a substrate. In FIG. 2, the charged body layer 2 is formed on the outer peripheral surface of the cylindrical base material 3, thereby forming the image carrier 1.
The charged body layer 2 formed on the outer peripheral surface of the substrate 3 is a resin having a volume resistance of 10 ¹⁵ Ωcm or more and a Rockwell M hardness of 70 degrees or more, such as polycarbonate resin or polyacetal. Resin can be used.

The material of the substrate 3 is not particularly limited, and examples thereof include poly (meth) acrylate, polyester such as polyethylene terephthalate and polybutylene terephthalate, polystyrene, polyvinyl acetal, polyamide, polyacetal, polyethersulfone, polyethylene, polypropylene, Resins such as polyurethane and polycarbonate, resins obtained by adding conductive materials such as carbon fiber and carbon black to these resins, and conductive metals such as aluminum, stainless steel, duralumin, copper, and iron ( Including alloys, the same shall apply hereinafter). Particularly when considering weight reduction, aluminum and duralumin are preferable.
When a conductive material such as a resin having conductivity and a metal having conductivity is used as the base material 3, the charged body layer 2 is formed as a thin layer, so that the amount of charged charges with respect to the charging potential can be reduced. This is a preferred embodiment because it reduces the charge and facilitates charging and discharging.

When a resin is used as the material of the base material 3, a resin produced in a cylindrical shape by a manufacturing method such as an extrusion molding method can be used as it is, or it can be used in a cylindrical shape by rounding a plate-like resin. Moreover, when using a metal, the metal pipe manufactured cylindrically by manufacturing methods, such as drawing | extracting, can be used as it is, or what was made cylindrical by rolling a plate-shaped metal etc. can be used.
0.5-20 mm is preferable, as for the thickness of the base material 3, 1-10 mm is more preferable, and 1-3 mm is still more preferable. This is because within this range, the strength of the image carrier can be maintained and the weight can be reduced.
The thickness of the charged body layer 2 only needs to have a thickness that can cover the substrate 3, preferably 0.05 to 300 μm, more preferably 0.1 to 100 μm. 10 μm is more preferable. This is because the potential can be maintained within this range.

The image carrier 1 in which the charged body layer 2 is formed on the outer peripheral surface of the cylindrical base material 3 is coated with a molten resin on the cylindrical base material 3 or a resin as a solvent. It is possible to prepare a coating material by dissolving it, and apply the coating material, or apply a resin that can be cross-linked by heat, ultraviolet rays, electron beams, etc., and then cure the coating material. As a coating method, a method of coating by a roll such as a doctor blade or a gravure roll, spraying, dipping or the like can be used.
For example, when a polycarbonate resin is used as the resin of the charged body layer 2, a polycarbonate resin is dissolved in a mixed solvent of methylene chloride and trichloroethane to form a paint, and this paint is applied by the above-described application method to form a cylindrical base material. The charged body layer 2 can be formed on the outer peripheral surface of 3.

Further, the charged body layer 2 is formed on the base material by the above-described method before the base material 3 is formed into a cylindrical shape, and then the base material 3 is rounded to form a cylindrical shape to produce the image carrier 1. Also good.
Such a cylindrical image carrier 1 is provided with a resin or metal flange or the like at its end, and can be incorporated into an image forming apparatus so that the flange or the like is connected to a driving device.

[Charging device]
The charging device is for making contact with a desired portion of the charged body layer of the image carrier and applying an electric charge to that portion to form an electrostatic latent image on the charged body layer. In the charging device, a plurality of conductive fine electrodes are formed on the insulating substrate in the same direction as the axial direction of the image carrier, and one or more rows of electrodes are arranged in a direction perpendicular to the axial direction of the image carrier. A well-known thing which is arranged can be used. For example, a charging device in which so-called needle electrodes and comb-shaped electrodes are formed, or a charging device in which a plurality of fine electrodes are arranged on a substrate as disclosed in FIG. 17 of Patent Document 7 (Japanese Patent Laid-Open No. 2002-172814). Can be preferably used.

The width between the electrodes of the charging device can be appropriately determined in consideration of the resolution of the electrostatic latent image, such as reducing the electrostatic latent image when high resolution is required for the electrostatic latent image.
For example, the width of the electrode is preferably 3 to 350 μm, more preferably 20 to 200 μm, and still more preferably 40 to 100 μm. Moreover, 1-100 micrometers is preferable, for example, as for the width | variety between electrodes, 3-50 micrometers is more preferable, and 5-30 micrometers is further more preferable. This is because, within such a range of the width of the electrode and the width between the electrodes, the electrode can be easily formed, and a high-resolution electrostatic latent image can be imparted to the image carrier.

The method for forming the electrode is not particularly limited. For example, a method of printing a conductive paste at a predetermined position using a screen plate on a resin film, a conductive layer having a desired thickness on a substrate, After coating the resist pattern only on the part you want to leave, the blast material is sprayed to remove the conductive material other than the electrode part, and the resist pattern is formed using a photosensitive resin on the resin film. After embedding the conductive paste in the recesses, a lift-off method (additive method) for removing the resist, forming a conductive layer with a desired thickness, covering only the portion desired to be left as an electrode, and then chemically etching, Various methods such as an etching method for removing the conductive material other than the electrode portion can be employed. Moreover, silver etc. can be vapor-deposited etc. on a base material, and an electrode pattern can also be formed.
In particular, since the charging device is in contact with the charged body layer of the image carrier, the base material of the charging device preferably has a certain degree of softness mainly composed of resin or rubber, and is preferably a thin plate or film. Those are preferred.

[Image forming apparatus having image carrier and printing using the same]
Next, an image forming apparatus having the image carrier of the present invention will be described.
FIG. 3 is a schematic diagram showing a configuration example when printing is performed using the image forming apparatus according to the embodiment of the present invention.
1 is an image carrier, 5 is a charging device, 6 is a developer container, 7 is a developer, 8 is a developing roller, 9 is a developer supply roller, and 10 is a developer. A regulating blade, 11 is a recording medium supply device, 12 is a recording medium, 13 is a transfer roller, and 14 is a fixing and fixing device.

As the image carrier 1, an image carrier having a structure as shown in FIG. 1 or 2 is used. The charging device 5 may be any device as long as it can charge a desired portion of the charged body layer 2 of the image carrier 1 with a predetermined resolution, and the above-described charging device can be used.
The charging device 5 is located upstream of the development process, and further upstream is provided with means for discharging the potential of the charged body layer 2 by grounding or the like, and means for charging with a polarity opposite to a predetermined potential. May be stabilized.

  As the developer 7 in the developer container 6, toner having negative polarity, toner having positive polarity, or the like can be used. For example, heat-melting resin such as styrene acrylic resin, polyester resin, urethane resin, acrylic resin, charge control agent such as salicylic acid metal complex, coloring of carbon black, copper oxide, yellow lead, nickel titanium yellow, bengara, resol red, etc. It is possible to use a developer such as a particle obtained by kneading and pulverizing an agent, a melting point adjusting component, and the like, or polymerizing by adding inside or outside.

As the developing roller 8, the developer supply roller 9, and the developer regulating blade 10, a developing roller, a developer supplying roller, and a developer regulating blade that are usually used in an electrophotographic image forming apparatus can be used. As the developing roller 8, for example, a developing roller made of a conductive elastic body provided with polyurethane foam, silicone rubber, nitrile butadiene rubber (NBR), ethylene propylene rubber (EPR) or the like on the outer periphery of a metal shaft or the like. It can be illustrated. Further, the surface of the developing roller 8 is for the purpose of adjusting surface roughness, electrical resistance or developer charging property, and for the purpose of adjusting the releasability of the developer from the developing roller. It may be painted. Examples of the developer supply roller 9 include a developer supply roller made of a conductive sponge roller such as a conductive polyurethane foam. Examples of the developer regulating blade 10 include a developer regulating blade in which a blade made of an elastic body such as polyurethane or rubber having a convex cross section and a brush is provided at one end of a support member such as a metal plate.
Further, the recording medium supply device 11, the recording medium 12, the transfer roller 13, and the fixing and fixing device 14 use the recording medium supply device, recording medium, the transfer roller 13, and the fixing and fixing device that are usually used in an electrophotographic printing apparatus. Can do.

The image forming apparatus of the present invention and the method for printing using this image forming apparatus will be described in detail below, taking as an example the case where the toner is positively charged.
The image carrier 1 is charged by the charging device 5, for example, by charging the potential of the portion of the charged body layer 2 of the image carrier 1 where the developer 7 is not transferred to +300 V, and grounding the portion where the developer 6 is to be transferred. Charge the potential to plus 5V. Thereby, an electrostatic latent image is formed on the charged body layer 2 of the image carrier 1.

  Further, the developer 7 existing in the developer container 6 is applied to the developing roller 8 connected to the plus 200 V power source by the developer supplying roller 9 connected to the plus 200 V power source, and the developer 7 is applied to the developing roller 8. Support. At this time, the developer 7 on the developing roller 8 is agitated and rubbed by the developer supply roller 9 to be positively charged, and the developing roller is in contact with one end of the developer regulating blade 10 and the surface of the developing roller 8. The developer 7 on 8 is regulated to form a developer layer on a thin layer. Thereafter, the developer 7 on the developing roller 8 comes into contact with the charged body layer 2 of the image carrier 1 by the rotation of the developing roller 8, and the developer 7 moves to a portion of the charged body layer 2 charged to + 5V. Since the developer 7 does not migrate to the portion charged to +300 V, the electrostatic latent image formed on the charged body layer 2 of the image carrier 1 is thereby developed and visualized.

Then, a recording medium 12 such as plain paper conveyed by the recording medium supply device 11 is conveyed to a transfer unit including the image carrier 1 and the transfer roller 13, and the developer 7 from the charged body layer 2 of the image carrier 1. Is transferred onto the recording medium 12 by moving toward the transfer roller 13 charged to minus 250V, for example. Thereafter, the recording medium 12 is transported to the fixing and fixing device 14, and the developer 7 is fixed to the recording medium 12, and printing is completed.
In the above method, the potential of the portion where the developer 7 of the charged layer 2 of the image carrier 1 is transferred from the developing roller 8 is +5 V, but the portion where the developer 7 is transferred is grounded to zero potential. Further, a negative voltage of about −5 to −50 V, which is much lower than that of the transfer roller 13, can be applied to make it slightly weakly charged. In particular, a positively charged state from zero potential is preferable.
Further, a voltage is applied to the charged body layer 2 of the image carrier 1 so as to have a predetermined potential. Prior to the voltage application, the charged body layer 2 is discharged by a method such as grounding or charged to the electrode opposite to the predetermined potential. It is also a preferable aspect to stabilize the electrostatic latent image by a method such as making it happen.

The image forming apparatus in the case where the developer 7 uses toner having a positive polarity and the method for printing using the image forming apparatus have been described above. However, the developer 7 uses toner having a negative polarity. The charged body layer 2 of the image carrier 1 is negatively charged, so that the electrostatic latent image formed on the charged body layer 2 is reversely developed and visualized, and the transfer roller 13 is charged positively to be developed. The agent 7 can be transferred to the recording medium 12. In addition, it is preferable to use a toner having a positive polarity because generation of ozone when charging the charged body layer 2 of the image carrier 1 can be suppressed.
As described above, according to the image carrier 1 of the present invention, it is not necessary to change the image carrier regardless of the negative polarity or the positive polarity of the developer 7. There is also an advantage that any of these developers can be used.

  Further, although not shown in FIG. 3, the image forming apparatus of the present invention includes a developer 7 remaining after transfer attached to the charged body layer 2 of the image carrier 1 as in the conventional image forming apparatus, A cleaning device that removes migrating substances from the recording medium 12 such as paper dust may be provided. When the cleaning device is provided, the cleaning device is disposed on the downstream side of the transfer unit and on the upstream side of the electrostatic latent image formation.

[Color printing using an image forming apparatus having an image carrier]
Next, a method for performing color printing using the image forming apparatus of the present invention will be described.
FIGS. 4 and 5 are schematic diagrams showing an example of the configuration when color printing is performed using the image forming apparatus of the present invention. FIG. 4 is a so-called intermediate transfer belt type color printing apparatus, and FIG. This is a so-called recording medium tandem type color printing apparatus.

  In FIG. 4, 15 is an intermediate transfer belt, 16 is a secondary transfer roller, and 17 is a rotating roller for rotating the intermediate transfer belt. In FIG. 5, 18 is a recording medium conveyance belt, and 19 is a rotating roller for rotating the recording medium conveyance belt. Further, in FIGS. 4 and 5, image forming apparatuses 21 to 24 having developers having respective colors in the order of yellow, magenta, cyan, and black are arranged from the bottom of the drawings. The configurations of these image forming apparatuses 21 to 24 are the same as those of the image forming apparatus as shown in FIG. 4 and 5, the same reference numerals are used for the same components as those in FIG.

In the case of the intermediate transfer belt type color printing apparatus of FIG. 4, first, the yellow developer is transferred from the yellow image forming apparatus 21 to the intermediate transfer belt 15 by the transfer roller (primary transfer roller) 13, and then magenta. The magenta, cyan, and black developers are sequentially transferred by the image forming apparatus 22, the cyan image forming apparatus 23, and the black image forming apparatus 24, and each developer is further transferred to the recording medium 12 by the secondary transfer roller. Then, fixing is performed by the fixing and fixing device 14, and color printing is completed.
If necessary, the intermediate transfer belt 15 can be cleaned or neutralized with an elastic roller or blade (not shown).

In the case of the recording medium tandem color image forming apparatus shown in FIG. 5, first, the yellow developer is transferred from the yellow image forming apparatus 21 to the recording medium 12 conveyed by the recording medium conveying belt 18 by the transfer roller 13. Next, magenta, cyan, and black developers are sequentially transferred by the magenta image forming device 22, the cyan image forming device 23, and the black image forming device 24, and are fixed by the fixing and fixing device 14, thereby performing color printing. Complete.
If necessary, the recording medium transport belt can be cleaned or neutralized by an elastic roller or blade (not shown).

4 and 5, image forming apparatuses having developers having respective colors in the order of yellow, magenta, cyan, and black are arranged from the lower side of the drawings, but this order can be changed as appropriate.
In addition, electrophotographic 4-cycle color printing can also be employed.

[Image forming apparatus having electric field curtain device]
The image carrier of the present invention is not limited to the image forming apparatus as described above, and can be used as an image carrier for an image forming apparatus having an electric field curtain device.
FIG. 6 is a schematic diagram showing another configuration example of the image forming apparatus of the present invention, and shows one configuration example of an image forming apparatus having an electric field curtain device using the image carrier of the present invention.
1 is an image carrier, 5 is a charging device, 6 is a developer container, 7 is a developer, 31 is an electric field curtain panel, 32 is an electrode, and 33 is for driving an electric field curtain. N-phase AC power source.

Since the image carrier 1 and the charging device 5 have been described above, description thereof is omitted here.
A plurality of electrodes 32 are formed on the electric field curtain panel 31, and a voltage is applied to the plurality of electrodes 32 by an n-phase AC power source 33 for driving the electric field curtain.
Further, the developer container 6 accommodates the developer 7, the electric field curtain panel 31, and the like, and has an opening partly opened, and is formed on the electric field curtain panel 31 by the opening part. A part of the plurality of electrodes 32 facing the image carrier 1.

Further, a part of the electric field curtain panel 31 and the plurality of electrodes 32 enter the developer pool in the developer container 6. When an AC voltage of three or more phases having different phases is applied to the plurality of electrodes 32 by the n-phase AC power source 33 for driving the electric field curtain, a moving electric field is generated in the plurality of electrodes 32, and From the developer pool, the developer 7 is successively conveyed above the electrode 32.
Here, the electric field curtain device means an apparatus including at least an electric field curtain panel 31, a plurality of electrodes 32 formed on the electric field curtain panel 31, and an n-phase AC power source 33 for driving the electric field curtain.

In such an image forming apparatus, for example, when toner having negative polarity is used as the developer 7, the potential of the portion where the developer 7 of the charged body layer 2 of the image carrier 1 is not transferred by the charging device 5 is negative. The portion where the developer 6 is to be transferred is charged positively. Then, the image carrier 1 becomes a facing electrode of the electrode 32, and the developer 7 on the electrode 32 moves to a positively charged portion of the charged body layer 2 of the image carrier 1. Then, since the developer 7 does not migrate to the negatively charged portion, the electrostatic latent image formed on the charged body layer 2 of the image carrier 1 is reversely developed and visualized.
In addition, although the case where the electric field curtain panel 31 was arrange | positioned horizontally was shown in FIG. 6, it may not be horizontal but may be diagonal, a part may be diagonal and a part may be horizontal. 6 shows a case where the bottom surface of the developer container 6 is horizontal, but the bottom surface of the developer container 6 is inclined so that the developer 7 that has not been transferred to the image carrier 1 can be collected in the developer pool. It may be.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
Example 1
(1) Image carrier Polycarbonate (manufactured by Mitsubishi Chemical Corporation) is mixed with methylene chloride and trichloroethane on the outer peripheral surface of a cylindrical conductive substrate 3 made of aluminum having a diameter of 40 mm, a thickness of 1.5 mm, and a length of 220 mm. The coating material dissolved in is applied and dried to form a charged body layer 2 having a thickness of 40 μm, and an image carrier 1 (image carrier 1a) for forming an electrostatic latent image as shown in FIG. 2 is manufactured. did.

And in order to measure the volume resistance of the polycarbonate which is the material of the charged body layer 2, a sample having a diameter of 100 mm and a thickness of 2 mm was prepared and measured by an JIS K6911 method using an insulation resistance meter manufactured by ADC. The volume resistance was 10 ¹⁶ Ωcm.
In addition, in order to measure the Rockwell M hardness of polycarbonate which is a material of the charged body layer 2, a sample having a diameter of 100 mm and a thickness of 2 mm was prepared and measured by a JIS K6911 method using a hardness meter manufactured by Matsuzawa Seiki Co., Ltd. However, the Rockwell M hardness was 82 degrees.

(2) Charging Device As the charging device 5, a charging device made of a flexible printed board having comb-shaped electrodes was used.
(3) Developer Kneading styrene acrylic resin (60 parts by mass), carbon black (35 parts by mass), wax (4 parts by mass), resin acid-modified cyanide charge control agent (1 part by mass), etc. The developer 7 having a positive chargeability with a particle size of 6 μm was obtained by pulverization and classification.

(4) Developing roller A polyurethane resin obtained by a reaction of a polybutadiene-based polyol having an allyl-type primary hydroxyl group at a terminal and tolylene diisocyanate (TDI) by a method described in Japanese Patent No. 2990005. A developing roller 8 having an outer shape of 16 mm on the outer periphery of the metal shaft was obtained.
(5) Developer supply roller By a method described in Japanese Patent No. 2855335, a 6 mm diameter sulfur free-cutting steel shaft subjected to electroless plating is coated with polyurethane foam, and a polyurethane-based hot melt film adhesive is used. The developer was supplied and cut so that the outer shape of the foam part was 12 mm to obtain a developer supply roller.

(6) Developer regulating blade The developer regulating blade 10 provided with ribs protruding in the length direction of the blade as described in JP-A-2004-163615 was used.
(7) Image Forming Apparatus An image forming apparatus as shown in FIG. 3 having the image carrier 1, the charging device 5, the developer 7, the developing roller 8, the developing supply roller 9 and the like was used.

(8) Printing conditions Printing was performed on plain paper recording medium 12 using an image forming apparatus as shown in FIG.
At this time, 4420 plain paper made by Xerox Co. was used as the recording medium 12, the potential of the developing roller 8 and the developing supply roller 9 was plus 200V, and the potential of the transfer roller 13 was minus 250V.
First, by the charging device 5, the potential of the portion of the charging layer 2 of the image carrier 1a where the developer 7 is not transferred is charged to + 300V, and the potential of the portion where the developer 7 is to be transferred is charged to + 5V. .
Next, the plain paper recording medium 12 conveyed from the recording medium supply device 11 was sent to the transfer section, printed by the image carrier 1 a and the transfer roller 13, and the developer 5 was fixed by the fixing and fixing device 14. When this printed matter was visually observed, it was confirmed that a good image was obtained.

Example 2
(1) Image carrier A cylindrical substrate made of polycarbonate (manufactured by Mitsubishi Chemical Corporation) having a diameter of 40 mm, a thickness of 1.5 mm, and a length of 220 mm is formed by an extrusion molding method, and this is as shown in FIG. An image carrier 1 (image carrier 1b) for forming an electrostatic latent image was obtained.
Since the polycarbonate which is the material of the image carrier 1b (charged body layer 2) is the same as that in Example 1, the volume resistance is 10 ¹⁶ Ωcm and the Rockwell M hardness is 82 degrees.

(2) Image forming apparatus and printing conditions In addition to the image carrier 1b, the charging device 5, the developer 7, the developing roller 8, the developer supplying roller 9, and the developer regulating blade 10 similar to those in the first embodiment are used. An image forming apparatus as shown in FIG. 3 was configured, and using this image forming apparatus, printing was performed on plain paper recording medium 12 under the same printing conditions as in Example 1, and developer 5 was fixed. When this printed matter was observed visually, it was confirmed that a good image was obtained as in Example 1.

Example 3
(1) Image carrier A cylindrical base material of polyacetal (manufactured by Polyplastics) having a diameter of 40 mm, a thickness of 1.5 mm, and a length of 220 mm is formed by an injection molding method. An image carrier 1 (image carrier 1b) for forming an electrostatic latent image was obtained.
And when the volume resistance and Rockwell M hardness of the sample which shape | molded the same material to the disk of diameter 100mm and thickness 2mm were measured similarly to Example 1, volume resistance is 10 < ¹⁷ > ohm-cm, Rockwell M hardness Was 90 degrees.
(2) Image forming apparatus and printing conditions Using this image carrier 1b, a printed matter was printed under the same image forming apparatus and printing conditions as in Example 2. When this printed matter was observed visually, it was confirmed that a good image was obtained as in Example 1.

Comparative Example 1
(1) Image carrier A cylindrical charged body layer 2 of phenol resin (manufactured by Hitachi Chemical Co., Ltd.) having a diameter of 40 mm, a thickness of 1.5 mm, and a length of 220 mm is formed by an injection molding method, and this is shown in FIG. Such an image carrier 1 (image carrier 1b) for forming an electrostatic latent image was used.
The volume resistance and Rockwell M hardness of the phenol resin as the material of the charged body layer 2 were measured in the same manner as in Example 3. The volume resistance was 10 ¹³ Ωcm and the Rockwell M hardness was 95 degrees. .
(2) Image forming apparatus and printing conditions Using this image carrier 1b, a printed matter was printed under the same image forming apparatus and printing conditions as in Example 2. When this printed matter was visually observed, the resolution of the image was inferior to that of Example 1, and the outline of the high-definition image was blurred.

Comparative Example 2
(1) Image carrier In the same manner as in Comparative Example 1, a cylindrical base material of polypropylene resin (manufactured by Mitsui Chemicals) was formed by an injection molding method, and the electrostatic latent image as shown in FIG. The image carrier 1 (image carrier 1b) for forming the image was formed.
Then, when the volume resistance and Rockwell M hardness of the phenol resin as the material of the charged body layer 2 were measured in the same manner as in Example 3, the volume resistance was 10 ¹⁶ Ωcm and the Rockwell M hardness was 65 degrees. .
(2) Image forming apparatus and printing conditions Using this image carrier 1b, a printed matter was printed under the same image forming apparatus and printing conditions as in Example 2. When this printed matter was visually observed, a good image was initially obtained, but as the number of printed sheets increased, white streaks began to appear, and when the image carrier surface was observed, scratches were found in the circumferential direction. It has occurred.

  As described above, based on the results of the examples and comparative examples, when the image carrier of the present invention is used, the image forming apparatus is configured by components such as an image carrier, a charging device, a developing roller, a developer supply roller, and a developer regulating blade. It is possible to print well without using heavy chargers and their power supplies, such as precision and expensive photoconductors and laser oscillation scanning devices, reducing the number of parts used in image forming devices, It was confirmed that the price and weight of the forming apparatus can be reduced and the image forming process can be simplified.

  The image carrier having a charged body layer and the image forming apparatus using the image carrier of the present invention can be suitably used for on-demand printing apparatuses such as printers, facsimiles, and copiers.

DESCRIPTION OF SYMBOLS 1 Image carrier 2 Charged body layer 3 Base material

Claims (6)

An image carrier used in an image forming apparatus, wherein a charged body layer on an outer peripheral surface of the image carrier is made of a resin having a volume resistance of 10 ¹⁵ Ωcm or more and a Rockwell M hardness of 70 degrees or more. Image carrier.   The image carrier according to claim 1, wherein the charged body layer is formed on the outer peripheral surface of the substrate.   The image carrier according to claim 2, wherein the substrate is a conductive substrate.   The image carrier according to claim 1, wherein the image carrier is a cylinder.   5. The image carrier according to claim 1, a charging device for forming an electrostatic latent image on a charged body layer of the image carrier, and a developer for transferring the developer to the surface of the image carrier. An image forming apparatus having a developing roller, a developer supply roller for attaching the developer to the developing roller, and a developer regulating blade for regulating the developer on the developing roller.   The image carrier according to any one of claims 1 to 4, a charging device for forming an electrostatic latent image on a charged body layer of the image carrier, and an electric field curtain for transferring developer to the charged body layer An image forming apparatus having the apparatus.

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