JPH0667549A - Image forming device - Google Patents

Abstract

PURPOSE:To obtain a high quality image without causing the degradation of resolution by providing a pressing means for transferring a toner image. CONSTITUTION:In this image forming device by which a latent image formed on a latent image carrier 1 by a latent image forming means is developed by sticking toner thereto by a developing device 3, a toner image formed on the latent image carrier 1 is once subjected to primary transfer on an intermediate transfer body 5, thereby forming a toner image on the intermediate transfer body 5, and the toner image formed on the intermediate transfer body 5 is subjected to secondary transfer on a recording material 15, the development device 3 is provided with nonmagnetic one-component developer, the intermediate transfer body 5 is made of a rubber elastic body whose surface is tacky, and the intermediate transfer body pressing means which transfers the toner image by pressing the surface of the intermediate transfer body 5 onto the toner image formed on the latent image carrier 1 by toner development is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for forming an image using an intermediate transfer member using toner of an electrostatic recording electrophotographic system or the like.

[0002]

2. Description of the Related Art In recent years, with the progress of multifunctionalization and full-colorization of image forming apparatuses, digitalization has been promoted. Further, with the spread of technology in the field of printing technology, expectations for improvement in image quality are increasing. As an image forming apparatus such as a conventional copying machine printer, an electrophotographic method is widely adopted,
The characteristics of this electrophotographic system are that it is high-speed, that an image with high image quality and excellent legibility can be obtained, and that the selection range of the recording material is large.

A conventional image forming apparatus having a structure including an intermediate transfer member is, for example, Japanese Patent Publication No. 46-41679.
JP-B, JP-B-48-22763, JP-A-49-
Some are disclosed in Japanese Patent No. 78559. These use an intermediate transfer member having a rubber member such as silicone rubber as a transfer material as a basic structure, and "press transfer" the toner image from the toner image carrier onto the intermediate transfer member,
The transferred toner image is melted and transferred onto a recording material. Further, as another conventional example, as disclosed in Japanese Patent Laid-Open No. 51-94939, a plurality of toner images are transferred to an intermediate transfer member in a multiplex manner, and then thermal transfer is performed on a transfer material. In a printing machine, a conductive member such as aluminum (Al) on which a layer of urethane or silicon is formed is used as the intermediate transfer member, and the transfer method of the intermediate transfer member is not the pressure transfer described above but the “static transfer”. Some of them are characterized by being performed by "electrotransfer".

[0004]

However, in the image forming method of the image forming apparatus having the above-mentioned intermediate transfer member, sufficient consideration should be given to the reproducibility of the fine pattern in order to improve the reproducibility of the digital image. I can't say I'm paying. In addition, sufficient measures are taken against instability of the image quality of the transferred toner image due to changes in temperature and humidity, deterioration of image quality due to scattering of toner that forms the toner image that occurs during transfer, and fluctuations in transferability depending on the type of transfer material. It cannot be said that
Furthermore, it is not intended to sufficiently improve the multiple transfer property of toner images such as full-color image formation.

Further, in order to improve the reproducibility of a digital image, it is necessary to develop a fine pattern by using a toner having a fine particle diameter. It has been found that it is difficult to perform uniform transfer in the transfer method.

[0006]

According to the first aspect of the present invention, the latent image formed by the latent image forming means on the latent image carrier is developed by adhering toner to the latent image by means of a developing device. The toner image formed on the image carrier is once primary-transferred onto the intermediate transfer member to form a toner image on the intermediate transfer member, and the toner image formed on the intermediate transfer member is transferred onto the recording material. In an image forming apparatus for forming an image by performing secondary transfer, the developing device includes a non-magnetic one-component developer, and the intermediate transfer member is formed of a rubber elastic body having an adhesive surface portion, An intermediate transfer member pressing means is provided for transferring the toner image by pressing the surface of the intermediate transfer member against the toner image formed by toner development on the latent image carrier.

According to a second aspect of the present invention, in the first aspect of the invention, the developing device has a toner carrier and a toner thin layer forming member for forming a thin film of a toner image on the toner carrier. did.

According to the invention of claim 3, claim 1 or 2
In the invention described above, the intermediate transfer member has an electrode layer, and bias voltage applying means for applying a bias voltage to the electrode layer is provided as necessary, and a plurality of types of toner images are transferred onto the intermediate transfer member in an overlapping manner. Overlapping transfer means was provided.

According to a fourth aspect of the invention, in the invention of the first, second or third aspect, the toner has an average particle size of 5
The toner is made of a fine particle size toner having a particle size of not more than μm.

According to a fifth aspect of the invention, in the invention of the first, second or third aspect, the toner has an average particle size of 5
The toner is composed of a spherical toner having a fine particle diameter of μm or less.

[0011]

According to the first aspect of the invention, by providing the developing device with the non-magnetic one-component developer, it is possible to reproduce a pure color image and to make the device compact. . Further, since the intermediate transfer body is formed of an adhesive rubber elastic body and the intermediate transfer body pressing means performs the pressure transfer onto the surface of the latent image carrier that carries the toner image formed by toner development, the intermediate transfer body is pressed onto the intermediate transfer body. It becomes possible to transfer a toner image substantially 100%,
This makes it possible to significantly improve the transfer rate of the toner image.

According to the second aspect of the present invention, the toner thin layer is formed on the toner carrier by the toner thin layer forming member, whereby the uniformity of toner charging can be improved.

According to the present invention, the bias voltage is applied to the intermediate transfer member having the electrode layer by the bias voltage applying unit, and the toner image on the intermediate transfer member is overlaid and transferred by the overlay transfer unit. Further, the transfer can be further performed on the adhesive surface of the intermediate transfer member coated with the toner image, whereby the multiple transfer can be surely performed.

In the invention of claim 4, by using a fine particle diameter toner having a particle size of 5 μm or less, a resolution is excellently provided as compared with the prior art, and it is most suitable for reproducing a digital image for developing fine dots. It becomes possible.

In the fifth aspect of the present invention, the fine particle toner is formed in a spherical shape of 5 μm or less, so that the toner image is attached to the toner carrier as a single layer as compared with the toner having an irregular particle diameter. By doing so, it becomes possible to reliably perform transfer to the intermediate transfer member at a transfer rate of almost 100%.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows an image forming apparatus capable of forming a full-color image. Therefore, first, the configuration of the image forming apparatus will be described. A photoreceptor 1 is provided as a drum-shaped latent image carrier, and an electrophotographic photoreceptor is used here. Around this photoconductor 1,
A charging device 2, a developing device 3 as a developing device, a pre-transfer exposure lamp 4, an intermediate transfer member 5, a static eliminator 6, a cleaning device 7, and an erase lamp 8 are arranged.
The image light 9 can be incident between the charging device 2 and the developing device 3 by a latent image forming means (not shown).
In addition, around the intermediate transfer member 5, the intermediate transfer member 5 is
A cleaning device 10, a pressing roller 11, and a heater lamp 12 for cleaning the above are disposed. A heater lamp 13 is arranged around the pressing roller 11. Further, a paper feeding unit 14 is arranged in front of the pressing roller 11. This paper feeding unit 14
The sheet feeding cassette 14a includes a first sheet feeding roller 14b and a second sheet feeding roller 14c.

The respective parts will be described in detail below. The charging device 2 charges the entire surface of the photoconductor 1. Image light 9
For example, laser light modulated by an image signal processed by an image processing unit (not shown) is used. The developing device 3
Is Y (yellow), M (magenta), C (cyan),
It has four developing devices 3Y, 3M, 3C and 3BK corresponding to the electrostatic latent images of each color of BK (black).

FIG. 2 shows the internal structure of the intermediate transfer member 5. In this intermediate transfer member 5, in order from the lower side,
The support 5a, the electrode layer 5b, the intermediate layer 5c, and the uppermost transfer layer 5d are formed. In this case, an adhesive rubber elastic body is used for the transfer layer 5d. As the rubber elastic body, for example, urethane rubber, ethylene propylene rubber, butyl rubber, chlorosulfonated polyethylene rubber, epichlorohydrin rubber, acrylic rubber, silicone rubber, fluororubber and the like can be used. When the secondary transfer (transfer from the intermediate transfer member 5 to the recording material 15) is performed by heating, silicone rubber excellent in transfer property and heat resistance is particularly effective. Further, as the electrode layer 5b, A
It is possible to use by forming a resin thin layer in which a vapor-deposited film, a plated film, a metal powder, and conductive fine powder such as carbon black are dispersed on a metal thin plate such as l, Cu, or Ag. Further, as the support 5a, a thin metal plate, polyester such as polyethylene terephthalate, polyethylene naphthalate, polyamide, polyimide, polyamide imide, polyphenylene sanfaldo, polyparabanic acid, polyether ketone, polycarbonate, polytetrafluoroethylene, A resin film such as a tetrafluoroethylene-hexafluoropropylene copolymer can be used.

As the material for the intermediate layer 5c, organic resins such as ethyl cellulose, nylon, casein, polyvinyl alcohol, vinyl acetate, urethane resin and epoxy resin are used, and various surfactants and ionic compounds such as quaternary ammonium salt compounds are used. A material containing the compound of (1) and a film-forming organic material such as a polymer having a chain structure of ion conductivity such as a quaternary ammonium salt compound in a vinyl monomer are effective.

The electrode layer 5b and the support 5a may be integrated so as to simplify the layer structure of the intermediate transfer member 5. For example, a thin metal plate may have both the functions of the support and the electrode. Also, the electrode layer 5b
As the above, the polyester resin film can be formed by incorporating conductive fine powder such as metal powder or carbon black into the resin film. Furthermore, as the intermediate layer 5c, 10 ³ Ωcm to 10
A thin layer of an inorganic or organic compound having a resistivity of ¹² Ωcm can be used.

Further, since the thin toner layer formed on the toner carrier (developing roller) is a single layer, when the latent image on the photoconductor 1 is subjected to toner development by the main developing unit 3, the toner image is formed on the photoconductor 1. Since a single-layer toner image is formed on the sheet, it is possible to obtain a transfer rate of 100% when pressure transfer is made to the adhesive intermediate transfer body 5. Further, since the discharged toner can be made extremely small, it contributes to resource saving, and the burden on the cleaning device 7 for the photoconductor 1 can be reduced, so that reliability such as stable image quality is improved. Will be able to.

The intermediate transfer member 5 as described above is the photosensitive member 1.
It has an intermediate transfer member pressing means (not shown) for pressing and transferring the surface of the intermediate transfer member 5 onto the toner image formed by electrostatic transfer. Further, as shown in FIG. 1, the intermediate transfer member 5 is connected to a transfer bias power source 16 as a bias voltage applying means for applying a bias voltage to the electrode layer 5b as necessary. Further, here, there is provided an unillustrated overlapping transfer means for transferring the toner images of four colors onto the intermediate transfer member 5 in an overlapping manner. Accordingly, when performing multiple transfer on the intermediate transfer member 5 by the overlapping transfer means, it is desirable to apply the transfer bias by using the transfer bias power supply 16 not only by pressing but also by the second transfer. The bias voltage value is usually 50
A voltage of 0 to 3000 V is applied.

The pre-transfer exposure lamp 4 attenuates the charges mainly on the photosensitive member 1 where there is no toner image, and the charges move to the intermediate transfer member 5 to move the intermediate transfer member 5.
Are prevented from being charged and the transferability is deteriorated. The heater lamp 12 heats the toner image on the intermediate transfer body 5, and the heater lamp 13 heats the recording material 15. As the cleaning device 10, a rotating brush, a contact brush or the like can be used in addition to the contact driven roller.
The second paper feed roller 14c has a function of registering the recording material 15 and the toner image on the intermediate transfer material 5.

The operation of this apparatus having such a configuration will be described. By irradiating the surface of the photoconductor 1 to which the entire surface is charged by the charging device 2 with the photosensitivity with the image light 9, a latent image by electrostatic charge is formed on the photoconductor 1. The image light 9 can be obtained by converting an original image read by a CCD or the like (not shown) into an electric signal, performing image processing as necessary, and modulating the laser light. The photoreceptor 1 on which the latent image is formed in this manner is selectively adhered by the developing device 3 to the toner, which is colored fine powder, either on a portion where electrostatic charge exists or a portion where electrostatic charge does not exist. In particular, when reading a color original, the original image is read by a CCD line sensor (not shown) and converted into color signals of three primary colors. Each color signal is subjected to image processing by an image processing circuit (not shown), converted into a four-valued signal of Y (yellow), M (magenta), C (cyan), and Bk (black), and the image light 9 is sequentially converted,
Image light 9 of Y, M, C, and Bk is obtained, whereby latent images by electrostatic charges corresponding to the respective colors are sequentially formed on the photoconductor 1. When the photoconductor 1 on which the latent image of each of these colors is formed comes to the position D by rotation, the developing devices 3Y, 3M, 3C, 3Bk
The latent image of each color is sequentially developed by the
A toner image of each color is formed on top.

In this way, Y, M, C, and
The toner images formed in the order of Bk are transferred onto the intermediate transfer member 5 at the primary transfer position T ₁ only by pressing, or are transferred in an overlapping manner by pressing and applying a transfer bias voltage. When performing multiple transfer on the intermediate transfer body 5, a transfer bias is applied by the transfer bias power supply 16. Then, at the transfer position T ₁ , the intermediate transfer member 5 carrying the multiple Y, M, C, Bk toner images in this manner transfers the multiple toner images onto the recording material 15 at the secondary transfer position T ₂ . To do. When the secondary transfer is electrostatic transfer, a transfer bias voltage is applied simultaneously with pressing by a transfer bias power source (not shown).
This transfer bias voltage is not always necessary. Such secondary transfer can be performed by heating the toner image with the heater lamps 12 and 13 and pressing the toner image in a softened or melted state. At this time,
Since the toner image transferred onto the recording material 15 is fixed at the same time as the transfer, the fixing device is not always required.

The recording material 15 fed from the paper feeding unit 14 is 2
At the next transfer position T ₂ , a permanent multiple image (full color image) can be obtained in which a toner image corresponding to an original document not shown is transferred and fixed. After that, the primary transfer position T ₁
The surface of the photoconductor 1 that has passed through is discharged by the static eliminator 6 to remove residual toner and residual charges, and becomes an environment in which adhered substances such as toner adhered on the photoconductor 1 are easily cleaned. Completely removed by 7. Photoreceptor 1 from which the deposits have been removed in this way
Are discharged by the erase lamp 8 to discharge non-uniform surface charges and charges trapped inside the photoconductor 1 and become reusable, whereby the image forming process can be performed again from the beginning. Becomes

As described above, the transfer layer 5 of the intermediate transfer member 5
The use of the rubber elastic body for d prevents the transfer toner image from being disturbed due to the high transfer rate and the scattering of the toner forming the toner image at the time of transfer, which is seen in the conventional electrostatic transfer, and thus the photoreceptor 1 It is possible to faithfully transfer the toner image formed on the upper surface. In this way, the intermediate transfer body 5 using the rubber elastic body can transfer the toner image formed on the photoconductor 1 only by pressing, but by providing the electrode layer 5b, the transfer rate is further increased. In addition, it is possible to prevent the deterioration of the toner image at the time of transfer as conventionally seen, and it is possible to transfer the toner image faithfully to the primary toner image on the photoconductor 1.

Further, by providing the electrode layer 5b on the intermediate transfer member 5 and applying the transfer bias voltage at the same time as the pressing, it is possible to effectively perform the multiple transfer of the toner images on the intermediate transfer member 5. As a result, conditions advantageous for full-color image formation can be obtained. That is, in the full-color image formation, it is desirable to form a so-called multiple transfer in which the toner images Y, M, C, and Bk of the respective colors are sequentially superimposed and transferred onto the intermediate transfer member 5, but the transfer layer 5d.
In the intermediate transfer body 5 provided with the rubber elastic body, the combined use of the pressing force and the bias voltage makes it possible to obtain an excellent multiple image without causing the image disturbance during the transfer.

Next, a second embodiment of the present invention will be described with reference to FIG. The description of the same parts as those in the first embodiment (see FIG. 1) is omitted, and the same reference numerals are used for the same parts.

While the first embodiment described above is characterized in that a plurality of toner images formed on the photoconductor 1 are transferred and formed on the intermediate transfer member 5 in a multiplex manner,
The present embodiment is characterized in that a plurality of toner images formed on the intermediate transfer member 5 are transferred in a multiple manner on the recording material 15 wound around the pressing roller 11. For this reason, as the pressing roller 11 here, a drum having a larger diameter is used to support the entire surface of the recording material 15 to be wound.

With such a structure, the paper feeding unit 14 is now in use.
The recording material 15 fed from the second feeding roller 14c is wound around the pressing roller 11 and is rotated at least by the number of toner images conveyed onto the intermediate transfer body 5 to perform multiple transfer. Is discharged. As a result, similar to the first embodiment, it is possible to obtain a high-quality image without lowering the resolution. In each of the first and second embodiments, the photosensitive member 1 and the intermediate transfer member 5 are drum-shaped members, but belt-shaped members may be used.

Next, a third embodiment of the present invention will be described with reference to FIG. The description of the same parts as those of the first and second embodiments (see FIGS. 1 and 2) is omitted, and the same reference numerals are used for the same parts.

FIG. 4 shows an example of an image forming apparatus equipped with an adhesive type intermediate transfer member and a developing device using a non-magnetic one-component developer. In the developing device 3, a developing roller 17 as a toner carrier, a toner supply roller 18 in contact with the developing roller 17, a toner thin layer forming member 19 in contact with the upper portion of the developing roller 17, and two members are provided. Agitators 20a and 20b, a toner 21 as a non-magnetic one-component developer, and a charge removing member 22 are provided.

In this case, the toner supply roller 18 is
In order to realize high frictional contact so that the toner 21 can be easily conveyed and the toner can be sufficiently supplied to the developing roller 17, a roller having a rotating brush porous surface or the like is preferable, and particularly, a urethane foam or the like is used. A foam roll and a sponge rubber roll provided with the material on the surface are convenient. Further, the toner supply roller 18 is made conductive,
By applying a bias voltage between the toner supply roller 18 and an electrode (not shown) of the developing roller 17, the toner 21 can be more reliably supplied to the surface of the developing roller 17. The agitator 20a,
20b is a toner 2 which is obtained by agitating the toner 21 in the developing device 3.
It has a function of preventing the blocking of No. 1 and ensuring the charging of the toner 21 and effectively conveying the toner 21 to the surface of the toner supply roller 18. The static elimination member 22
Removes or equalizes the charges on the developing roller 17 that has completed the developing process or the remaining toner 21.

As the material of the toner thin layer forming member 19,
Metals such as aluminum (Al) and stainless steel, resins such as fluorine-containing resins, rubber materials such as urethane, and non-plate bases or roll bases made of rubber material to prevent thermal adhesion of the toner 21. A plate or roll provided with a resin such as a fluorine-containing resin having an adhesive property can be conveniently used. Further, in the present embodiment, the toner thin layer forming member 19 is described as a plate-shaped member, but a roll-shaped member may be used. The roll-shaped toner thin layer forming member is used even in a stationary state, but is usually used in a rotating state to develop a part of the toner 21 supplied by the toner supply roller 18 to the rotating developing roller 17. It is rotated at a peripheral speed or a rotation direction capable of being scraped into the container 3.

As the toner bearing member, a belt-shaped member is used in addition to the roller-shaped member such as the developing roller 17, and in the normal case, each is formed by an electrode and a toner-bearing layer. In this case, as the toner carrying layer, urethane resin,
Insulating resin layer such as acrylic resin, silicone resin, fluorine-containing resin, layer made conductive or semi-conductive by containing conductive fine powder in this insulating resin layer, surface to improve toner carrying property A roughened metal layer, a layer containing so-called float electrode particles electrically independent of each other in an insulating resin, and the like can be selected according to the target image quality.

A pre-transfer exposure lamp 4 is arranged around the photosensitive member 1. The pre-transfer exposure lamp 4 attenuates the electric charge remaining after development on the developing roller 17 to improve the transfer rate, prevents image drooling during transfer of a toner image due to discharge between the developing roller 17 and a transfer member, and records. The material 15 is provided as necessary in order to prevent excessive charging of the material 15 and to improve the separation performance of the recording material 15 after transfer from the developing roller 17.

A belt-shaped intermediate transfer member 5 is used. A rubber elastic body having an adhesive surface is used for the belt 5a of the intermediate transfer body 5, and among these rubber elastic bodies, silicone rubber is a material having excellent adhesive transferability and thermal transferability. The transfer pressing roller 23a and the tension roller 23 are provided on the inner wall surface of the belt 5a.
b, a separation roller 23c, and a drive roller 23d are arranged.

In this case, the transfer pressing roller 23a presses the intermediate transfer member 5 against the toner image on the photosensitive member 1 at an appropriate transfer pressure at the transfer position T ₁ to transfer the toner image to the intermediate transfer member 5. It has the function of transferring to the top. The tension roller 23b maintains the intermediate transfer body 5 at an appropriate tension so that the intermediate transfer body 5 can always be stably driven. Further, the tension roller 23b may be swung to prevent the intermediate transfer body 5 from shifting.
The separation roller 23c is for smoothly separating the recording material 15, and a roller having a relatively small diameter is used.
The cleaning roller 23e is rotatably in contact with the separation roller 23c via the belt 5a. The drive roller 23d is connected to a drive system (not shown),
The intermediate transfer body 5 is being driven. The drive roller 23d is a heat roller having a heater 24 therein,
The heater 24 and the pressing roller 11 together with the intermediate transfer member 5
The upper toner image can be thermally transferred onto the recording material 15. In addition, in order to improve the thermal transfer property, the pressing roller 1
For 1 as well, it is better to provide the heater 25 inside thereof.
The operation of this apparatus having such a configuration will be described. The toner 21 between the developing roller 17 and the toner supplying roller 18 at the contact portion F is charged by the pressing force or the frictional force to the developing roller 17 due to the relative movement between the developing roller 17 and the toner supplying roller 18,
The developing roller 17 is electrostatically attached. The toner 21 thus attached to the developing roller 17 is conveyed toward the toner thin layer forming member 19. It has been observed that by applying a bias voltage to the toner supply roller 18, the toner 21 can be more reliably attached to the developing roller 17. The bias voltage applied to the toner supply roller 18 is modulated by the image signal, for example, by using the electrophotographic photoreceptor 1 as the latent image carrier, charging the entire surface by the charger 2 so as to have a negative polarity, and modulating the image signal. When a negative-positive latent image is formed by irradiating the photoconductor 1 with the image light 9, the toner 2 charged with a negative polarity is used.
1 is attached to the laser light irradiation portion to develop toner,
In this case, a negative polarity voltage is applied.

The surface of the developing roller 17 is neutralized by the static eliminating member 22, and the residual toner 21 is substantially cleaned by the rotation of the toner supplying member 17 in the direction of the arrow, whereby the developing roller 17 is initialized. The developing process is continuously performed by sequentially repeating the toner supply, the thin layer formation, and the development. The toner thin layer forming member 19 has a plate shape, and the edge portion of the plate shape contacts the surface of the developing roller 17. The plate-shaped toner thin layer forming member 19 may have a method in which the edge portion contacts the surface of the roller or a method in which the belly portion contacts the surface of the developing roller 17. Then, the toner 21 adhered onto the developing roller 17 supplied by the toner supply member 17 has a non-uniform film thickness, and a part thereof is scraped off by the toner thin layer forming member 19 to form a thin layer. The thinned toner layer supported on the developing roller 17 is the toner thin layer forming member 1.
When 9 are in contact with each other, uniform charging is performed at the same time as thinning, so that a latent image formed on the photoconductor 1 can be developed into a high image. The toner layer of the developing roller 17 thus uniformly thinned and uniformly charged is conveyed to the developing position D to develop the latent image on the photoconductor 1, and toner corresponding to an image signal (not shown) on the photoconductor 1 is developed. An image is formed.

At the primary transfer position T ₁ , the toner image is transferred onto the intermediate transfer member 5 by pressing the intermediate transfer member 5 against the toner image on the photosensitive member 1 with the transfer pressing roller 23a at a predetermined pressure. Let The intermediate transfer member 5 thus primary-transferred is transferred through the tension roller 23b to
It is conveyed to the driving roller 23d at the next transfer position T ₂ .
The drive roller 23d has a heat roller inside and can thermally transfer the toner image on the intermediate transfer member 5 onto the recording material 15. Further, in order to improve the heat transfer property, the pressing roller 11 has a heat source 25 inside. Transfer can be performed by such a series of working steps.

The developing roller 17 which is a toner carrier.
When a drum-shaped one is used, it is preferable that the developing roller 17 has an elastic surface in order to prevent damage to the roller and improve the image quality by a soft phenomenon that reduces the effect of scraping off the toner 21 adhering to the roller. Although the developing device 3 has described that the developing roller 17 performs toner development by contacting the developing roller 17 with the photoconductor 1 at the developing position D, the photoconductor 1 and the developing roller 17 are in non-contact state at the developing position D. You may make it develop. In this case, the developing bias voltage applied between the photoconductor 1 and the electrode of the developing roller 17 may be only the DC bias voltage, but superimposing the AC bias voltage enhances the flying property of the toner 21 during toner development. It is preferable in improving the image density and gradation.

As the developing method, the developing device 3 using the non-magnetic one-component developer (toner 21) has been described. The developing device 3 forms a thin layer of the toner 21 on the developing roller 17 and forms a toner film. The toner image transfer to the intermediate transfer body 5 can be performed in the image forming apparatus having the intermediate transfer body 5 that can control the thickness in a very thin range and is made of an elastic body having an adhesive surface as in the present embodiment. This is extremely convenient for improving the transfer rate.

Next, the particle size of the toner used in the three embodiments described above will be described. The toner according to the present invention is a fine particle diameter toner having an average particle diameter of 5 μm or less. By using such a toner having a fine particle diameter, a resolution superior to that of a conventional image forming apparatus is given, and it is particularly effective for reproducing a digital image in which fine dots are developed. In this case, the average particle size is 5 μm
The following fine toner particles can be formed by a polymerization method without a crushing step. This forming method is characterized in that polymer particles are formed by polymerization and a coating layer such as a coloring agent is provided on the polymer particles. The polymerized toner can easily be made finer than the conventional pulverized toner, and can be made uniform in particle diameter and spherical, so that high image quality and stable image quality can be achieved.

Further, the following effects can be added by spheroidizing the fine particle size toner having an average particle size of 5 μm. The spherical toner has excellent fluidity and excellent replenishment property as compared with the pulverized toner obtained by pulverization, and does not contaminate the carrier in the two-component development because it does not contain the over-pulverized toner. In the developing device that uses the component developer, the toner carrier (developing roller 17) is not contaminated, and thus the reliability of the image forming apparatus can be further improved.

Since the toner thin layer formed on the toner carrier (developing roller 17) is a single layer, when the latent image on the photoconductor 1 is subjected to toner development by the main developing device 3, the photoconductor 1 Since a single-layer toner image is formed on the upper surface, it is possible to obtain a transfer rate of 100% when pressure transfer is made to the adhesive intermediate transfer member 5. Further, since the discharged toner can be made extremely small, it contributes to resource saving, and the burden on the cleaning device 7 for the photoconductor 1 can be reduced, so that reliability such as stable image quality is improved. Will be able to.

Carrier contamination in two-component development, or
Toner filming that occurs on the surface of the toner carrier in a developing device that uses a non-magnetic one-component developer deteriorates the charge control of the toner, and toner that has a charge opposite to that of the proprietary charge is generated, causing image fog and This may cause image contamination and dirt inside the machine due to toner scattering. If the toner image on the latent image carrier (photoreceptor 1) expands due to the pressure of the recording material 15 against the toner image or the transfer rate decreases, a high image cannot be obtained, but how to prevent such development It is desirable that the toner image on the latent image carrier is adhered in a single layer. Therefore, by using a spherical toner as in the present embodiment, it is possible to attach the toner to the latent image carrier in a single layer as compared with the irregular toner obtained by pulverization, and therefore, about 100% of the intermediate transfer member is used. A transfer rate of% can be reliably performed.

[0048]

According to the first aspect of the invention, the latent image formed on the latent image carrier by the latent image forming means is developed by adhering toner to the latent image carrier, thereby developing the latent image carrier. The toner image formed on the intermediate transfer member is first transferred onto the intermediate transfer member to form a toner image on the intermediate transfer member.
The toner image formed on the intermediate transfer member is printed on the recording material.
In an image forming apparatus for forming an image by performing a next transfer, the developing device includes a non-magnetic one-component developer,
The intermediate transfer body is formed of a rubber elastic body having an adhesive surface portion, and the surface of the intermediate transfer body is pressed against a toner image formed by toner development on the latent image carrier to form a toner image. Since the intermediate transfer member pressing means for transferring the image is provided, it is possible to reproduce a pure color image by using the non-magnetic one-component developer as described above and to make the apparatus compact. Also,
By forming the intermediate transfer member by an adhesive rubber elastic body and performing the pressure transfer on the surface of the latent image carrier electrostatically transferred by the intermediate transfer member pressing means, the toner image is substantially 100% on the intermediate transfer member. It is possible to transfer the image, and thereby, the transfer rate of the toner image is increased, the resolving power is significantly improved, and a high-quality image can be obtained.

According to the second aspect of the invention, the developing device has a toner carrier and a toner thin layer forming member for forming a thin film of a toner image on the toner carrier, so that the toner thin layer forming member is provided. By forming a thin toner layer on the toner carrier, the uniformity of toner charging can be improved.

According to a third aspect of the present invention, the intermediate transfer member has an electrode layer, and bias voltage applying means for applying a bias voltage to the electrode layer is provided to the electrode layer so that plural kinds of toner images can be transferred to the intermediate transfer member. Since the superimposing transfer means for superimposing and transferring the image on the intermediate transfer body is provided, the superimposing transfer means superimposes and transfers the toner image on the intermediate transfer body while the bias is applied to the intermediate transfer body having the electrode layer by the bias voltage applying means. By doing so, it is possible to further perform adhesive transfer onto the adhesive surface of the intermediate transfer member coated with the toner image, and thereby to reliably perform multiple transfer.

According to the fourth aspect of the present invention, the toner is made of a fine particle diameter toner having an average particle diameter of 5 μm or less. Therefore, a digital image which gives a resolution superior to that of the conventional toner and develops fine dots is provided. It can be optimized for image reproduction.

According to the fifth aspect of the invention, since the toner is composed of a fine particle spherical toner having an average particle diameter of 5 μm or less, the toner image has a single-layered structure as compared with a toner having an irregular particle diameter. The toner can be attached to the toner carrier, and thus, the transfer can be reliably performed to the intermediate transfer member at a transfer rate of almost 100%.

[Brief description of drawings]

FIG. 1 is a side view showing a configuration of an image forming apparatus that is a first embodiment of the present invention.

FIG. 2 is a sectional view showing an internal structure of an intermediate transfer member.

FIG. 3 is a side view showing a configuration of an image forming apparatus which is a second embodiment of the present invention.

FIG. 4 is a side view showing a configuration of an image forming apparatus which is a third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Latent image carrier 3 Developing device 5 Intermediate transfer body 5b Electrode layer 5d Rubber elastic body 15 Recording material 16 Bias voltage applying means 17 Toner carrier 19 Toner thin layer forming member 21 Non-magnetic one-component developer

Claims (5)

[Claims] 1. A latent image formed on the latent image carrier by the latent image forming means is developed by adhering toner to the latent image on the latent image carrier, and the toner image formed on the latent image carrier is once developed. The primary transfer is performed on the intermediate transfer member to form a toner image on the intermediate transfer member, and the toner image formed on the intermediate transfer member is secondarily transferred on the recording material to form an image. In the image forming apparatus, the developing device includes a non-magnetic one-component developer, the intermediate transfer member is formed of a rubber elastic body having an adhesive surface portion, and is formed on the latent image carrier by toner development. An image forming apparatus comprising: an intermediate transfer member pressing unit that transfers the toner image by pressing the surface of the intermediate transfer member against the toner image. 2. The image forming apparatus according to claim 1, wherein the developing device includes a toner carrier and a toner thin layer forming member that forms a thin film of a toner image on the toner carrier. 3. The intermediate transfer member has an electrode layer, and bias voltage applying means for applying a bias voltage to the electrode layer is provided to the electrode layer to transfer a plurality of types of toner images in an overlapping manner on the intermediate transfer member. The image forming apparatus according to claim 1 or 2, further comprising an overlapping transfer unit. 4. The image forming apparatus according to claim 1, wherein the toner is a fine particle toner having an average particle diameter of 5 μm or less. 5. The toner comprises a fine particle spherical toner having an average particle diameter of 5 μm or less.
The image forming apparatus according to 2 or 3.