JP3061901B2 - Image forming apparatus, cleanerless image forming apparatus, and color image forming apparatus - Google Patents

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, and more particularly to an image forming apparatus which can be downsized and has high image quality.

[0002]

2. Description of the Related Art An image forming apparatus using an electrophotographic system has been widely known, and has been widely used in electronic copying machines, electrostatic recording apparatuses and the like. FIG. 3 shows a main part of the configuration of this type of image forming apparatus, that is, a scanner section for reading a document provided in the main body of the image forming apparatus, and an image signal output from this scanner section as a digital signal. 1 is a cross-sectional view of the configuration of an image forming section 1 of an image forming section for copying and reproducing a required image based on image information of each color by the image processing section. As shown in FIG. 3, an image forming unit 1 of the image forming apparatus includes a latent image holding member (for example, a photosensitive drum) 1a and a charging unit (for example, corona charging) for uniformly charging the surface of the latent image holding member 1a. 1b) electrostatic latent image forming means 1c for forming a required electrostatic latent image on the surface of the latent image holding member 1a charged based on image information from the image processing section, and toner on the electrostatic latent image surface Developing means 1d for supplying an electrostatic latent image to a toner image, transferring means (transfer charging device) 1e for transferring the toner image to a transfer material surface, and holding a latent image remaining after the transfer in the transfer. It has a configuration provided with cleaning means 1f for removing from the surface of the body 1a.

According to this image forming apparatus, first, charging means
After the surface of the latent image holding member 1a is uniformly charged by 1b, a required electrostatic latent image is formed on the latent image holding member 1a by the electrostatic latent image forming means 1c and is developed by the developing means 1d. Thereafter, the obtained toner image is transferred and fixed to the transfer material surface by the transfer means 1e, so that a required image is copied and recorded on the transfer material surface.

[0004]

However, the image forming apparatus having the above configuration has the following problems in practical use. That is, this type of image forming apparatus also has an excellent image forming function, but it is desired to reduce the size of the image forming apparatus including the image forming section. However,
When the image forming unit is made compact as described above, the developing time of the developing unit 1d, for example, the time required for developing the electrostatic latent image formed on the surface of the latent image Unless the contact time with the electrostatic latent image surface is strictly controlled, there is a problem that fogging, insufficient density, or line bleeding occurs in the developed toner image. In other words, unless the development time is too long or too short and is not set appropriately, the developed image may vary and a high-quality image may not be formed.

The present invention has been made in view of the above circumstances, and has as its object to provide an image forming apparatus which can always form a high quality image and can be made compact.

[0006]

An image forming apparatus according to the present invention comprises: a latent image carrier; an electrostatic latent image forming means for forming an electrostatic latent image on the surface of the latent image carrier; and the electrostatic latent image surface. One component non-magnetic
By adhering sex toner an image forming apparatus including a transfer means for transferring a developing means to form a toner image, and the toner image on the transfer material, contact with the developing means a latent image holding member surface of said image forming unit A developing roller having elasticity and conductivity that rotates by rotating the developing roller, the outer diameter of the developing roller is D _d (mm), the moving speed of the surface is V _d (mm / sec), and the contact width with the surface of the latent image holding member. Is set to N (mm), 6 ≦ D _d ≦ 15 and 0.01 ≦ N / V _d ≦ 0.2.

[0007]

According to the present invention, the relationship between the rotation speed of the developing roller in the developing means and the contact width with the latent image holding member is set, and the developing conditions (developing time: contact of the developing roller with the electrostatic latent image surface) are set. By appropriately controlling the time, development of the electrostatic latent image is achieved with high accuracy. Further, in the present invention, when the developing / simultaneous cleaning is configured, the contact between the developing roller and the electrostatic latent image progresses steadily with the appropriately regulated developing conditions as described above. Insufficient adhesion (insufficient density) or excessive adhesion of toner (fog or bleeding of lines) is completely eliminated, and a sharp toner image is surely formed. The occupied spatial volume can be omitted.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a cross-sectional view showing an example of a main part (image forming unit) of a color image forming apparatus according to the present invention, and FIG. 2 is an enlarged view of one image forming unit (cleanerless image forming unit). Are shown in cross-section. The image forming section includes, for example, a cleanerless image forming unit 2 for yellow, a cleanerless image forming unit 3 for magenta, a cleanerless image forming unit 4 for cyan, and a cleanerless image forming unit 5 for black. ing. Each of the cleanerless image forming units 2, 3, 4, and 5 has a latent image holding member (for example, a photosensitive drum) 2a, 3a, 4a, 5a, and a latent image holding member 2a, 3a, A charging means (for example, a corona charger) 2b, 3b, 4b, 5b for uniformly charging the surfaces 4a, 5a, and a latent charged on the basis of image information from a separately provided image processing unit (not shown). Electrostatic latent image forming means (print head) 2c, 3c, 4c, 5c for forming a required electrostatic latent image on the surface of the image carriers 2a, 3a, 4a, 5a; Developing rollers 2d ₁ , 3d ₁ , 4d that supply non-magnetic toner to convert electrostatic latent images into toner images
_1, a developing unit 2d having a 5d _1, 3d, 4d, 5d, transfer means 2e including transfer charging roller for transferring to a transfer material surface the toner image, 3e, 4e, 5e, the toner image on the transfer material surface After transfer, the charge remaining on the surfaces of the latent image carriers 2a, 3a, 4a, 5a is removed (erased)
The charge removing lamps 2f, 3f, 4f, and 5f, and the transfer residual toner remaining in the transfer are dispersed on the surfaces of the latent image holding members 2a, 3a, 4a, and 5a, and the charging by the charging units 2b, 3b, 4b, and 5b is performed. Dispersing means 2 for untransferred toner which contributes to uniformity and promotes the cleaning action in developing means 2d, 3d, 4d, 5d
g, 3g, 4g, and 5g. That is, although a different color toner is used, a so-called cleanerless image forming apparatus (unit) is continuously provided.

Reference numeral 6 denotes a transfer material transfer means for transferring a transfer material for transferring a toner image, and a substantially transparent endless belt 6a for sequentially transferring a transfer material to which the toner image is transferred, for example, transfer paper. , A rotating mechanism (such as a roller) 6b for running the belt 6a endlessly, and a running belt 6a
It comprises a belt cleaner 6c for cleaning the surface, a belt charger 6d for charging the surface of the traveling belt 6a, and the like. The endless belt 6a, which is a part of the transfer material transporting means 6, transfers the transfer material sequentially supplied from the paper feed roller 7 in conjunction with the image formation. , 4e, 5e, a transfer area is formed by forming a required transfer electric field.

In FIG. 1, reference numeral 8 denotes a fixing unit for fixing the toner image transferred onto the transfer paper to the surface of the transfer paper;
Denotes a partition between the cleanerless image forming units 2, 3, 4, and 5.

The construction and function of the developing means 2d, 3d, 4d, 5d constituting the components of the color image forming apparatus according to the present invention will be described. The latent image holding bodies 2a, 3a, 4a, 5a are arranged to face each other. Rotary developing rollers 2d ₁ , 3d ₁ , 4d ₁ , 5d ₁ carrying a toner layer on the formed peripheral surface, and these developing rollers 2d ₁ , 3
d ₁ , 4d ₁ , 5d ₁ Toner supply unit 2 that supplies toner to _one surface
_{d 2, 3d 2, 4d 2} , 5d 2, the developing roller 2d _1, 3d ₁ above,
4d ₁ , 5d ₁ Toner layer regulating blades 2d ₃ , 3d ₃ , 4d ₃ , 5d ₃ for regulating the thickness of the toner layer carried on the surface, and the electrostatic charge of the latent image holders 2a, 3a, 4a, 5a developing roller 2d ₁ after supplying toner to the latent image surface, 3d _1, 4d _1, the toner collecting blade 2d ₄ for collecting the toner 5d _{1 side, 3d 4, 4d 4, 5d} 4 and toner while wearing them Storing the toner storage tank 2d
_5, and a _{3d 5, 4d 5, 5d 5} .

The developing rollers 2d ₁ , 3d ₁ , 4d ₁ , 5d ₁ of the developing means 2d, 3d, 4d, 5d have elasticity and conductivity and generally have an outer diameter of 3 to 14 mm. It is preferable that a rigid core (for example, a metal conductor) is formed by coating an elastic layer having a thickness of 0.5 to 6 mm on the peripheral surface. The elastic layer has a hardness of about 20 to 50 degrees and a resistance value of 10 ⁹ Ω · cm. It is desirable that: Then, the developing rollers 2d ₁ , 3d ₁ , 4d ₁ , 5d ₁
Rotates and carries a toner layer on the peripheral surface thereof, a required electrostatic latent image is formed latent image holding member 2a, 3a, 4a, but faces the 5a face, this time developing roller 2d _1, 3d The outer diameter of ₁ , 4d ₁ , 5d ₁ is D _d (mm), the moving speed of the surface is V _d (mm / sec), and the contact width between the latent image holding members 2a, 3a, 4a, and 5a is N (mm). ), The developing rollers 2d ₁ , 3d ₁ , 4d ₁ , 5d with respect to the latent image holding members 2a, 3a, 4a, 5a so as to satisfy 6 ≦ D _d ≦ 15 and 0.01 ≦ N / V _d ≦ 0.2. ₁ contact time is set. The reason is that as D _d becomes smaller, the latent image carriers 2a, 3a,
4a, 5a and the developing roller _{2d 1, 3d 1, 4d 1} , 5d 1 inevitably contact time for the contact width is small (developing time) N / V
_d becomes smaller. That is, if the developing time is too short, the transfer of the toner becomes incomplete, and the density is insufficient, fog and sharpness are deteriorated. Therefore, in the range of 6 ≦ D _d ≦ 15, the developing time is set within the range of 0.01 ≦ N / V _d ≦ 0.2. If the value is less than 0.01, the density is insufficient and the sharpness is deteriorated. If the value is more than 0.2, the development time is too long.

Further, the developing rollers 2d ₁ , 3d ₁ , 4d ₁ , 5d
The outer diameter of ₁ is limited to the above range, if the outer diameter is too large, the compactness of the image forming apparatus as the initial purpose is not achieved, and if the outer diameter is too small, the developing rollers 2d ₁ , 3d ₁ ,
Production of 4d ₁ and 5d ₁ becomes difficult.

Next, an outline of development and simultaneous cleaning in the cleanerless image forming units 2, 3, 4, and 5 will be described. When an electrostatic latent image is formed on the surface of the latent image holding member 2a, 3a, 4a, 5a by the electrostatic latent image forming means 2c, 3c, 4c, 5c, the electrostatic latent image is present in a charged portion (that is, an unexposed portion or a non-image portion). transfer residual toner, because they are surely charged charging means 2b, 3b, 4b, by 5b, the developing roller 2d _1, 3
d _1, 4d _1, 5d ₁ from the latent image holding member 2a, 3a, 4a, suppresses the toner to 5a faces to metastasize field, i.e. the potential of the charged portion and the developing roller _{2d 1, 3d 1, 4d 1} , 5d _The developing roller 2d ₁ , 3d ₁ , 4
Transfer to d ₁ , 5d ₁ side. At the same time the non-charged portion, namely the transfer residual toner present on the exposed portion or image portion developing roller _{2d 1, 3d 1, 4d 1} , 5d 1 from the latent image holding member 2a, 3a, 4
a, 5a receiving the force toward the latent image carrier (photoconductor) 2a, 3a, 4a,
It remains on the 5a surface. The developing roller 2
New toner is transferred from d ₁ , 3d ₁ , 4d ₁ , and 5d ₁ , and cleaning is performed simultaneously with development. In addition, the developing rollers 2d ₁ , 3d ₁ , 4d ₁ , and 5d ₁ for simultaneously performing the development and the cleaning of the transfer residual toner are opposed to the latent image holders 2a and 3d.
Since the appropriate contact time (development time) is set for the surfaces a, 4a, and 5a, development and cleaning are performed accurately. A high-quality toner image obtained by developing the electrostatic latent image formed on the surface of the latent image holding members 2a, 3a, 4a, 5a is transferred by the next transfer means 2e, 3e, 4e, 5e. After being transferred to the surface of the material, the image is fixed and finally a high-quality color image is formed.

In the transfer means 2e, 3e, 4e, 5e, the transfer charging roller constituting the transfer means 2e, 3e, 4e, 5e is played in concert with a dielectric or resistor forming the belt 6a. If it is made to act, a required transfer electric field is easily and reliably formed in the transfer area, and transfer is performed efficiently. In other words, the belt 6a is formed of a dielectric or a resistor having a resistance value of 10 ⁹ Ωcm or more, and at least one surface thereof has a function of imparting charge,
It is easy to form a transfer electric field, so that the latent image carrier 2
The toner images formed on the surfaces a, 3a, 4a, and 5a are entirely transferred onto the transfer material surface without toner particles forming the toner image remaining on the latent image holding members 2a, 3a, 4a, and 5a. Is done. Therefore, since the transfer residual toner is also greatly reduced, a clear high-quality color image is formed in combination with the suppression of the generation of a positive image due to the simultaneous development and cleaning in the developing units 2d, 3d, 4d, and 5d. It becomes possible.

According to the color image forming apparatus having the above configuration,
First, a necessary electrostatic latent image pattern is formed on the surface of the latent image holding member (photoconductor) 2a by information corresponding to the yellow image,
In the next stage of the developing means 2d, development and simultaneous cleaning are performed according to the above-described operation principle, and a high-quality toner image corresponding to the electrostatic latent image pattern is formed on the surface of the latent image holding member 2a. You. The toner image thus formed is
The image is transferred from the surface of the latent image holding member 2a to the surface of the transfer material conveyed synchronously by the transfer means 2e. After the transfer, the surface of the latent image holding member 2a is irradiated with a static elimination lamp 2f to remove the charge, and then substantially uniformly dispersed by the dispersing means 2g of the transfer residual toner, and the surface of the latent image holding member 2a is made uniform. The formation of the electrostatic latent image pattern corresponding to the yellow image, development, simultaneous cleaning, etc. are repeated again.

On the other hand, the transfer material on which the yellow image has been transferred is conveyed to the next cleaner-less image forming unit 3 for magenta, and is operated by the same operation or operation as in the cleaner-less image forming unit 2 for yellow. On the transfer material surface on which the yellow image has been transferred, a required magenta image is transferred in a laminated manner. Thereafter, in the cleaner-less image forming unit 4 for cyan and the cleaner-less image forming unit 5 for black, a corresponding color image is formed into a toner image and transferred, and then fixed by the fixing unit 11 to obtain a required color. An image is obtained.

Each of the cleanerless image forming units 2
In the image forming process in 3, 4, and 5, so-called cleaning means is not separately provided, but the developing means 2d, 3d, and 4 are used.
By the simultaneous development and cleaning by d and 5d, the transfer residual toner on the surface of the latent image holding members 2a, 3a, 4a and 5a is easily and surely removed, so that the color mixture and the image shift of the toner images of each color can be prevented. Thus, a clear (sharp) high-quality color image is always formed.

In the above-described color image forming apparatus, all of the image forming units are the cleanerless image forming units 2, 3, 4, and 5, but in the present invention, these are formed as image forming units with cleaning means. Is also good. For example, the image forming unit located at the most upstream side along the flow direction of the transfer material may be the cleaner-less image forming unit 2 for yellow, and the other may be an image forming unit with a dedicated cleaning unit. Can be more effectively avoided. Alternatively, the image forming unit located at the most downstream side in the flow direction of the transfer material is designated as a cleaner-less image forming unit 5 for black, and the other image forming units are provided with dedicated cleaning means (or with dedicated cleaning means). the image forming unit and may be a cleanerless image forming units), it may be used to form a monochrome image by leaving a relatively large capacity of the toner storage tank 5d ₅ of the cleaner-less image forming unit 5 for black in this arrangement . Further, the image forming unit located at the most downstream side in the flow direction of the transfer material is an image forming unit with a cleaning unit for yellow or an image forming unit with a cleaning unit for cyan, and the other is also a cleanerless image forming unit. Often, even in this configuration, the effect of color mixing can be avoided more effectively.

As described above, in the image forming apparatus according to the present invention, the cleaning means may or may not be provided. However, from the viewpoint of making the image forming apparatus compact, the cleanerless image forming apparatus is preferred. It is preferable that Further, in the color image forming apparatus of the above configuration example, the static elimination lamps 2f, 3f, 4f, 5f are arranged inside the substantially transparent endless belt 6a.
It is also permissible to dispose the static elimination lamps 2f, 3f, 4f, 5f outside of 6a to make the endless belt 6a opaque.
However, static elimination lamps 2f, 3 are provided inside the endless belt 6a.
By arranging f, 4f and 5f, the color image forming apparatus can be made more compact by utilizing the space in the transfer area.

In the above embodiment, the case where the present invention is applied to a color image forming apparatus provided with a plurality of image forming apparatuses has been described. However, the present invention is applied to a normal single-color image forming apparatus. In this case, it is extremely effective.

[0023]

As described above, according to the image forming apparatus of the present invention, the contact between the developing roller and the electrostatic latent image in the developing means steadily proceeds. Alternatively, excessive adhesion of toner (fog and bleeding of lines) is completely eliminated, and a sharp toner image can be surely formed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration example of a main part of a color image forming apparatus according to the present invention.

FIG. 2 is an enlarged sectional view showing a cleanerless image forming unit in a configuration example of a main part of the color image forming apparatus according to the present invention.

FIG. 3 is a cross-sectional view illustrating a configuration of a main part of a conventional image forming apparatus.

[Explanation of Signs] 1. Image forming unit 1a, 2a, 3a, 4a, 5a ... Latent image holder
1b, 2b, 3b, 4b, 5b ... Charging means 1c, 2c, 3c, 4c, 5c, 6c,
7c, 8c ... electrostatic latent image forming means 1d, 2d, 3d, 4d, 5d ... developing means 1e, 2e, 3e, 4e, 5e ... transferring means 1f ... cleaning means 2f, 3f, 4f, 5f ... static elimination lamp 2g, 3g, 4g, 5g ... transfer residual toner dispersing means 2, 3, 4, 5 ... cleanerless image forming unit _{2d 1, 3d 1, 4d 1} , 5d 1 ...
Developing rollers 2d ₂ , 3d ₂ , 4d ₂ , 5d ₂ … Toner supply
2d ₃ , 3d ₃ , 4d ₃ , 5d ₃ … toner layer regulating blade
_{2d 4, 3d 4. 4d 4} , 5d 4 ... toner collecting blade 2d
_{5, 3d 5, 4d 5,} 5d 5 ... toner reservoir 6 ... transfer material conveying means 6a ... belt 6b ... rotating mechanism 6c ... belt cleaner 6d ... belt charger 7 ... feed roller 8 ... fixing unit 9 ... cleanerless image forming Divider between units

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yukihiro Osugi 6-78 Minamicho, Mishima-shi, Shizuoka Tokyo Electric Company, Ltd. Technical Research Institute (56) References JP-A-61-159664 (JP, A) JP-A-53 -3233 (JP, A) JP-A-1-17886 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 15/08

Claims (3)

(57) [Claims] 1. A latent image bearing member, an electrostatic latent image forming means for forming an electrostatic latent image on the surface of the latent image holding member, one on the electrostatic latent image surface
An image forming apparatus comprising: developing means for forming a toner image by attaching a component non-magnetic toner; and transfer means for transferring the toner image to a transfer material, wherein the developing means contacts a latent image holding member surface. A rotating developing roller having elasticity and conductivity is provided. The outer diameter of the developing roller is D _d (mm), and the moving speed of the surface is V _d (mm / se).
c) Image formation characterized by satisfying 6 ≦ D _d ≦ 15 and 0.01 ≦ N / V _d ≦ 0.2 assuming that the contact width with the surface of the latent image holding member is N (mm). apparatus. 2. A latent image carrier, an electrostatic latent image forming means for forming an electrostatic latent image on the surface of the latent image carrier, and a one-component non-magnetic toner adhered to the surface of the electrostatic latent image to form a toner image. A cleaner-less image forming apparatus comprising: a developing unit that forms; and a transfer unit that transfers the toner image to a transfer material, wherein the developing unit has elasticity and conductivity that rotates in contact with a surface of the latent image holding member. Roller, the outer diameter of the developing roller is D _d (mm), and the moving speed of the surface is V _d (mm / se).
c) a cleaner-less configuration characterized by satisfying 6 ≦ D _d ≦ 15 and 0.01 ≦ N / V _d ≦ 0.2, where N (mm) is a contact width with the surface of the latent image holding member. Image forming device. 3. A latent image carrier, an electrostatic latent image forming means for forming an electrostatic latent image on the surface of the latent image carrier, and a one-component non-magnetic toner adhered to the surface of the electrostatic latent image to form a toner image. What is claimed is: 1. A color image forming apparatus comprising: a plurality of image forming apparatuses including a developing unit for forming and a transfer unit for transferring the toner image to a transfer material, the plurality of image forming apparatuses being arranged along a transfer material conveying path. Is provided with a developing roller having elasticity and conductivity that rotates in contact with the surface of the latent image holding member. The outer diameter of the developing roller is D _d (mm), and the moving speed of the surface is V _d (mm / sec). ), The contact width with the surface of the latent image holding member is N (mm)
Wherein: 6 ≦ D _d ≦ 15 and 0.01 ≦ N / V _d ≦ 0.2.