CN101339389A

CN101339389A - Image forming apparatus

Info

Publication number: CN101339389A
Application number: CNA2008101280875A
Authority: CN
Inventors: 远藤理惠; 森谷修司; 境泽胜弘; 高桥宪生
Original assignee: Canon Inc
Current assignee: Canon Inc
Priority date: 2005-11-01
Filing date: 2006-11-01
Publication date: 2009-01-07
Anticipated expiration: 2026-11-01
Also published as: CN1959555A; CN100511013C; CN101339389B

Abstract

An image forming apparatus includes an image bearing member; a developer carrying member, contactable to the image bearing member, for carrying a developer to a developing position to develop an electrostatic image formed on the image bearing member with the developer; a supplying member for supplying the developer to the developer carrying member, wherein a peripheral speed of the developer carrying member is not less than 1.05 times and not more than 1.20 times a peripheral speed of the image bearing member, and an arithmetic average roughness Ra is not less than 0.20 times and not more than 0.33 times a volume average particle size of the developer, wherein a potential applied to the supplying member is different from a potential applied to the developer carrying member toward a larger potential of a regular charge polarity of the developer.

Description

Imaging device

Patented claim of the present invention be that November 1, application number in 2006 are 200610143135.9 the applying date, denomination of invention divides an application for the application for a patent for invention of " imaging device ".

Technical field

The present invention relates to a kind of imaging device that adopts electric photography formula or electrostatic recording formula process, for example laser beam printer, duplicating machine or facsimile recorder.

Background technology

Usually for example in the imaging device that adopts electric photography formula process, charged by charging device in the surface of electric camera photosensitive member (photosensitive member) (image bearing member), use light to make the face exposure of Electrifier frame, photoreceptor afterwards, thereby on the surface of Electrifier frame, photoreceptor, form electrostatic image (sub-image) according to the image information modulation.Toner with the developer that provides from developing apparatus makes this electrostatic image development become toner image.This toner image is transferred on the transfer materials (print paper, OHP sheet material, fabric etc.) from Electrifier frame, photoreceptor, makes toner image by fixing device then.

Developing method as being used to toner image is developed for example uses the single component development system of monocomponent toner to put in the practical application.In the single component development system, be used for the rotatable reagent delivery component of developer replenishing photosensitive drums is rotated with suitable relative speed difference with respect to Electrifier frame, photoreceptor, and for example with Electrifier frame, photoreceptor crimping in imaging device or contact.

Employed here developer is the monocomponent toner that just is made of resin material toner-particle (toner) basically.Developer can comprise the material (auxiliary particle) that adds the outside to be regulated flowable and makes the chargeable ability of toner stable.Toner-particle itself can include wax.Wax is used for by for example recording paper is dazzling and improve separating of transfer materials and fixing device toner image employed photographic fixing oil during on the transfer materials being prevented recording materials (transfer materials).Adopt the advantage of the developing method of non-magnetic mono-component developer to be, in developer,, therefore can simplify this equipment and make it miniaturization without any need for magnetic material.In addition, adopt the advantage of the developing method of non-magnetic mono-component developer to be, so for example because good painted characteristic is applicable to full color imaging equipment.

At first with reference to Fig. 8, this figure demonstrates a kind of developing apparatus of routine.

In Fig. 8, reagent delivery component is the developer roll 21 with elasticity and electric conductivity.Reagent delivery component with the image bearing member crimping or contact, is that the situation hypograph bearing carrier of rigid member is impaired easily at reagent delivery component therefore during development operation.For this reason, developer roll 21 is made by elastic component.On the surface of developer roll 21, conductive layer can be set, and can apply the development bias voltage thereon.

Developer toner component for adjusting scraper plate 22 contacts with developer roll, forms uniformly thin toner layer and toner is applied electric charge.In this case, form is that the toner scraper plate 22 of rubber-like elastic metallic or rubber flap is supported on the scraper plate support metal plate, and contacts with the outside surface of developer roll near its free end.When adjusting scraper plate 22 was not arranged on the opening part of developer container, it was arranged on resilient roller 23 downstreams in developer container.

In this developer container, resilient roller 23 contacts and rotates with developer roll.Resilient roller 23 is the sponge roller, and being used for provides toner and remove the residue toner from developer roll 21 to developer roll 21.

Employing has the developing apparatus of said structure, can form the nonmagnetic toner thin layer satisfactorily on developer roll 21, therefore can make the latent electrostatic image developing on photosensitive drums 24 satisfactorily.To drive developer roll 21, so that the image that does not have to blur and have enough image densities basically is provided than photosensitive drums 24 higher peripheral speeds.Basically do not have fuzzy video high density in order to provide, the Japan flat 11-221219 of special permission publication application has for example disclosed the adjusting of the peripheral speed ratio between photosensitive drums 24 and developer roll 21.

But, with than the higher speed drive reagent delivery component of image bearing member to provide when not having fuzzy video high density basically, be subjected to friction force in the contact gap of the toner on reagent delivery component in the contact toning system.Therefore, at this equipment running hours, toner goes bad owing to the friction force that applies in the contact gap between reagent delivery component and image bearing member and/or heat.The rotten material (being deposited on the periphery of toner) that refers to outside interpolation of toner is embedded in the toner and/or the outside material that adds discharges from toner.Because rotten, thus the minimizing of the quantity of electric charge of unit toner weight, and/or the agglomeration increase of toner-particle, thereby cause image deflects for example to produce dual imaging etc.

Summary of the invention

Therefore, fundamental purpose of the present invention is to provide a kind of imaging device, adopts this imaging device can suppress owing to the rotten image deflects that cause of developer, and therefore can realize long-term availability.

Another object of the present invention is to provide a kind of imaging device, wherein can prevent because the developer friction in the contact area between reagent delivery component and image bearing member and destruction that developer is caused keeps the picture rich in detail that has enough image densities and do not produce blurred background basically simultaneously.

The present invention specifically discloses following content:

(1). a kind of imaging device comprises:

Image bearing member;

Reagent delivery component can contact with described image bearing member, is used for developer is carried to developing location, makes the electrostatic image development that is formed on the described image bearing member with developer;

Delivery member is used for to described reagent delivery component supply developer,

Wherein, the peripheral speed of described reagent delivery component is not less than 1.05 times of peripheral speed of described image bearing member and is not more than its 1.20 times, arithmetic average roughness Ra is not less than 0.20 times of the equal granularity of body of developer and is not more than its 0.33 times, the current potential that is applied on the described delivery member is different with the current potential on being applied to described reagent delivery component, more near the big current potential of the normal charge polarity of developer.

(2). as (1) described equipment, it is characterized by, described delivery member is arranged to contact with described reagent delivery component.

(3). as (1) described equipment, also comprise the developer adjustment means, this developer adjustment means contacts with the surface of reagent delivery component, is used for being adjusted in the amount of the developer that carries on the described reagent delivery component.

(4). as (1) described equipment, it is characterized by, the degree of depth that described image bearing member is pressed in the described reagent delivery component is not less than 10 μ m and is not more than 50 μ m.

(5). as (1) described equipment, it is characterized by, the shape coefficient SF-1 that is included in the toner-particle in the developer is not less than 100 and be not more than 160, and its shape coefficient SF-2 is not less than 100 and be not more than 140, and described shape coefficient SF-1 and SF-2 limit by following equation:

SF-1={ (absolute maximum length) ²The projected area of/toner-particle } * (π/4) * 100;

SF-2={ (circumferential length) ²The projected area of/toner-particle } * (1/ π 4) * 100.

(6). as (1) described equipment, also comprise second image bearing member and second reagent delivery component that can contact with described second image bearing member, be used for developer is carried to developing location, to be formed on electrostatic image development on described second image bearing member with developer, wherein, the ratio of the peripheral speed of described reagent delivery component and the peripheral speed of described first image bearing member is less than the ratio of peripheral speed with the peripheral speed of described second image bearing member of described second reagent delivery component.

(7). as (6) described equipment, it is characterized by, the developer that is carried on the described reagent delivery component is a color developer.

(8). as (1) described equipment, it is characterized by, described developer is non-magnetic single component developer.

To know the understanding these and other purposes, features and advantages of the present invention more by the following explanation of reading the preferred embodiment of the present invention that provides in conjunction with the accompanying drawings.

Description of drawings

Fig. 1 is the synoptic diagram of imaging device according to an embodiment of the invention.

Fig. 2 is the synoptic diagram of developing apparatus according to an embodiment of the invention.

Fig. 3 is the synoptic diagram of developing apparatus according to an embodiment of the invention.

Fig. 4 is the synoptic diagram of handle box according to an embodiment of the invention.

Fig. 5 is the synoptic diagram of imaging device according to an embodiment of the invention.

Fig. 6 demonstrates the characteristic of the average surface roughness relation of fuzzy in an embodiment of the present invention generation and toner coating amount and developer roll.

Fig. 7 demonstrates the characteristic of the average surface roughness relation of fuzzy in an embodiment of the present invention generation and toner coating amount and developer roll.

Fig. 8 is the synoptic diagram of the example of traditional developing apparatus.

Embodiment

[embodiment 1]

With reference to these accompanying drawings imaging device according to the present invention is described in more detail below.

Fig. 1 is the schematic cross sectional views according to imaging device of the present invention, and Fig. 2 is the schematic cross sectional views of the developing apparatus that this imaging device adopted.

At first the general structure and the operation of the imaging device 1 of formation according to the present invention are described with reference to Fig. 1.

Imaging device 1 in this embodiment is a kind of laser beam printer, and it utilizes the electric photographic imaging method to go up at an offset medium (recording paper, OHP sheet material, fabric etc.) and forms image and export this recording medium.More particularly, it forms image according to the image information signal from image information source (for example personal computer, original document reading apparatus etc.) on recording medium, this image information source is connected with the master component of imaging device 1, thus can be between image information source and imaging device 1 transmission information.Imaging device 1 in this embodiment is provided with developing apparatus, and it uses the non-magnetic mono-component developer.

With reference to Fig. 1, electric camera photosensitive member 2 (below will be called as photosensitive drums 2) is along being rotated by the direction shown in the arrow in the figure.Along with photosensitive drums 2 is rotated, the circumferential surface of photosensitive drums 2 is by charging roller 3 chargings as charging device, to preset polarity (being negativity in this embodiment) and potential level.Afterwards, the charging circumferential surface is exposed to from the laser beam 5 as the laser optics 5a of exposure device.Therefore, on the circumferential surface of photosensitive drums 2, form electrostatic latent image.Reagent delivery component is pressed on the circumferential surface of photosensitive drums 2, thereby reagent delivery component obviously enters photosensitive drums 2 scheduled volumes.Latent electrostatic image developing is become the visual image that forms by developer (toner).Afterwards, this visual image is called toner image.

On the recording medium that is transferred to by transfer roll 7 as the toner image of visual sub-image on the photosensitive drums 2 as offset medium.By the cleaning balde 8 that constitutes cleaning device is that cleaning element is promptly stayed the toner that is not transferred on the photosensitive drums 2 with the transfer printing residual toner and wiped off.After photosensitive drums 2 is wiped off, the transfer printing residual toner is stored in the used toner case.After being cleaned, photosensitive drums 2 is used to form next image; Photosensitive drums 2 is used for above-mentioned imaging process repeatedly.

Simultaneously, by 9 pairs of fixing devices just now on it transfer printing recording medium (offset medium) heating of toner image is arranged.After photographic fixing, in the slave unit master component recording medium is discharged.

Next with reference to Fig. 2 the developing apparatus that above-mentioned imaging device was provided with is described.

With reference to Fig. 2, developing apparatus 4 has developing apparatus container 10, wherein stores developer, more particularly is non-magnetic monocomponent toner.The normal polarity that toner can be filled with is a negativity.Developing apparatus container 10 has the opening that extends along the longitudinal direction of developing apparatus container 10.Developing apparatus 4 is provided with the developer roll 11 that constitutes reagent delivery component.Developer roll 11 is located in the developing apparatus container 10, and it faces toward photosensitive drums 2 by above-mentioned opening, becoming visual image at the latent electrostatic image developing on the photosensitive drums 2.

As developer, adopt the non-magnetic mono-component developer.Wherein a kind of internal additives of developer (toner) is wax (toner-particle includes wax), so this is owing to following reason adds: conventionally use photographic fixing oil to be beneficial to offset medium and separate with fixing device 9.But photographic fixing oil makes recording medium (offset medium) easily when anchoring at toner on the recording medium for example recording paper is dazzling.Therefore, wax is joined in the tabulation of inner toner adjuvant, so that offset medium separates with fixing device 9, and without photographic fixing oil.In addition, in order to improve the transfer efficiency that toner forms higher-quality image, will join toner as the monox of the external additive that is used for improving the toner flowability.That is to say that the surface-coated of toner-particle has the external additive film to be filled with the ability of negative electricity to improve toner, and among toner-particle, form the microcosmic gap to improve the toner flowability.As can metal oxide (aluminium oxide, titanium dioxide, strontium titanates, ceria, magnesium oxide, chromium oxide, tin oxide, zinc paste etc.), nitride (silicon nitride etc.) and carbonide (silit etc.) etc. being arranged for the outside toner adjuvant of used in this embodiment toner use.In addition, can use slaine (calcium sulphate, barium sulphate, lime carbonate etc.), fatty acid metal salts (zinc stearate, calcium stearate etc.), carbon black, monox etc.The toner of per 100 weight portions adds these external additives of 0.01-10 weight portion, preferably adds the 0.05-5 weight portion.These external additives can use separately or be used in combination.They preferably have hydrophobicity.If the amount of the external additive that is added is not more than 0.01 weight portion, then monocomponent toner (for example in this embodiment the sort of) is mobile relatively poor, and is therefore poorer aspect transfer efficiency and development efficient.In addition, form the even image of density unevenness, and/or so-called " dispersion phenomenon " occur; Toner scatters along the border between the white space of image-region that is covered by toner and image.On the other hand, if the external additive amount in monocomponent toner is no less than 10 weight portions, the unnecessary amount of external additive is attached on photosensitive drums 2 and the developer roll 11, thus feasible being difficult to the toner charging, the inhomogeneous image of therefore easy formation.As for the shape of toner-particle, the shape coefficient SF-1 of expectation toner is not less than 100 and be not more than 160, and this shape coefficient demonstrates the sphericity of the particulate material that can measure with image analysis equipment.In addition, the numerical value of the shape coefficient SF-2 of toner expectation is not less than 100 and be not more than 140.As long as the shape coefficient SF-1 of toner and SF-2 think that then the particle of toner is spherical, and its surface are smooth in above-mentioned scope.By the way, adopt following method to obtain the shape coefficient SF-1 and the SF-2 of employed toner in this embodiment.That is to say, use FE-SEM (S-800:Hitachi, the product of Ltd.) to take the photo of 100 toner-particles that pick up at random with 500 times magnification.Then, the image information that will obtain like this by interface is imported among the image analysis equipment Luzcx 3 (Nikore Co., the product of Ltd.) with analysis image information and is analyzed.Limit shape coefficient SF-1 and SF-2 by following equation:

SF-1＝{(MXLNG) ²/AREA}×(π/4)×100

SF-2＝{(PERI) ²/AREA}×(1/π4)×100

AREA: the projected area of toner-particle

MXLING: absolute maximum length

PERI: circumferential length

By the way, for the relation between shape coefficient and true form, shape coefficient SF-1 represents the sphericity of particle, and shape coefficient SF-1 is big more, and then sphericity is better.Shape coefficient SF-2 represents the degree of irregularity of particle surface, and shape coefficient SF-2 is big more, and then particle surface is just inhomogeneous more.Therefore, its surface coefficient SF-1 and the SF-2 toner-particle in above-mentioned scope rolls easily, and easily by the friction uniform charging.Therefore, the amount of the particle that can not charge or fill with opposite polarity of its shape coefficient SF-1 and SF-2 toner in the above range still less.By the way, uncharged toner-particle makes imaging device form fuzzy image with the particle of filling the polarity opposite charges with.Therefore in addition, the toner that shape coefficient SF-1 and SF-2 are in above-mentioned scope is charged equably, in excellence aspect the consistance of electric field.Therefore, it can be used as developer better, and aspect transfer printing excellence, thereby even see it is favourable from forming the high quality graphic aspect, this need be with latent electrostatic image developing in micro details.In addition, the transfer printing of toner is higher, and this has reduced toner and has stayed amount on the photosensitive drums 2.

Elasticity developer roll 11 is horizontally set on the above-mentioned opening part of developing apparatus container 10, and the right half one (shown in Figure 2) is positioned at developing apparatus container 10 and the left side half one exposes from developing apparatus container 10.The circumferential surface that faces toward photosensitive drums 2 from the zone that developing apparatus container 10 exposes of the circumferential surface of developer roll 11.Photosensitive drums 2 is positioned on the left side of developing apparatus 4, and developer roll 11 keeps being pressed against on the circumferential surface of photosensitive drums 2, thereby developer roll 11 obviously invades in the photosensitive drums 2 with scheduled volume.The average magnitude that developer roll 11 obviously invades in the photosensitive drums 2 is desirably on the circumferencial direction of developer roll 11 in the scope of 10 μ m-50 μ m." obviously intrusion amount " refer to developer roll 11 during developer roll 11 keeps being pressed against on the photosensitive drums 2 the residing position of circumferential surface and photosensitive drums 2 remove separately and do not make the rotation of developer roll 11 move after distance between the residing position of circumferential surface of developer roll 11.If obviously the average magnitude of invading is not more than 10 μ m, then developer roll 11 toner that is difficult to will to be attached to from photosensitive drums 2 on the zone corresponding with the Image blank zone of circumferential surface of photosensitive drums 2 strikes off.Therefore, not only so-called fuzzy formation toner promptly remains adhered to the amount increase of toner in the zone corresponding with Image blank zone of the circumferential surface of photosensitive drums 2, nor may realize enough image density levels reliably.On the other hand, if obviously the intrusion amount increases above 50 μ m, then the friction between developer roll 11 and photosensitive drums 2 is excessive, then makes toner rotten easily.That is to say, be attached to the lip-deep external additive particle of toner-particle and be embedded into easily in the toner-particle that perhaps with the adjusting particle separation, and toner reduces the amount of its per unit charging easily.In addition, the easier cohesion of toner-particle.Therefore, form defective image easily and afterimage for example occurs.

The photosensitive drums 2 of composing images bearing carrier is a rigid member, and by as the aluminium cylinder of substrate be coated in that the photographic layer to predetermined thickness constitutes on the circumferential surface of aluminium cylinder.Before photosensitive drums 2 is carried out the actual imaging process, give photosensitive drums 2 chargings by charging roller 3.The circumferential surface of the photosensitive drums 2 of charging is exposed to from throwing simultaneously scanning laser beam with the image information signal modulation as the laser scanner of exposure device (image writer) in the mode of swing.Therefore, on the circumferential surface of photosensitive drums 2, form electrostatic image.Next, toner as developer is provided for the electrostatic image that is formed on the photosensitive drums 2 by developing apparatus 4, thereby is transformed into the visual image (toner image) that forms by toner; To become toner image by developing apparatus 4 at the latent electrostatic image developing on the photosensitive drums 2 with toner.

In this embodiment, the developer roll 11 acroleic acid polyurethane rubber layer that is coated to 20 μ m thickness by the bottom that forms with silicon rubber with on the circumferential surface of bottom constitutes; It has two-layer main layer.Its resistance is 10 ³-10 ⁷Ohm.Between metal core that the 100V DC voltage is applied to developer roll 11 and the stainless steel cylinder and make that developer roll 11 and stainless steel cylinder remain in contact with one another during, according at external diameter being the resistance that current amount flowing calculates developer roll 11 between the stainless steel cylinder of 30mm and the developer roll 11.As the material of elastic layer, can use General Purpose Rubber for example silicon rubber, urethane rubber, butyl rubber, ECD, butadiene rubber, ethylene-propylene-dience rubber (EPDM), any foam of making etc. by previous.When using its normal polarity of filling with, can use to be applicable to the toner triboelectric charging to the material as the superficial layer that is used for developer roll 11 such as the urethane resin of negativity, silicone resin as the toner of negativity.On the other hand, when using its normal polarity of filling with, can use to be applicable to the toner triboelectric charging to the material as the superficial layer that is used for developer roll 11 such as fluoride resin of positivity as the toner of positivity.As for the hardness of developer roll 11, using its hardness of being measured by Asker-C sclerometer (Koobunshi Keiki Co., the product of Ltd.) under the situation that applies 1 kilogram of load is 35 °-65 ° developer roll 11.Preferably, the hardness of the developer roll of measuring by the Asker-C sclerometer 11 is 40 °-60 °.

Direction rotation shown in the arrow A in Fig. 2 drives developer roll 11.Set the peripheral speed of developer roll 11, its peripheral speed with photosensitive drums 2 is compared, be not less than 105% and be not more than 120%.The diameter of developer roll 11 is 16mm.The sense of rotation of developer roll 11 is set for and is made that circumferential surface travel direction in the contact area between developer roll 11 and photosensitive drums 2 of developer roll 11 is identical with circumferential surface travel direction in contact area of photosensitive drums 2.If the above-mentioned peripheral speed of developer roll 11 is not more than 105% of photosensitive drums 2, therefore then in fact in contact gap, between developer roll 11 and photosensitive drums 2, have virtually no friction, be transferred on the photosensitive drums 2 and the toner that is attached on circumferential surface corresponding with blank parts image the zone of photosensitive drums 2 can not be got back on the developer roll 11 from developer roll 11.Therefore, increased fuzzy formation toner.Especially, if the peripheral speed of developer roll 11 is 100% with respect to the ratio of the peripheral speed of photosensitive drums 2, promptly when the peripheral speed between developer roll 11 and photosensitive drums 2 during, between the circumferential surface of developer roll 11 and photosensitive drums 2, have virtually no friction without any difference.Therefore, form very fuzzy image easily.On the other hand, if the peripheral speed of developer roll 11 surpasses 120% with respect to the ratio of the peripheral speed of photosensitive drums 2, then the friction between developer roll 11 and photosensitive drums 2 becomes excessive.Therefore, even the fuzzy toner that forms reduces, increased destruction to toner; Be attached to the lip-deep external additive of toner-particle and be embedded in the toner-particle, and/or external additive separates with toner-particle.In other words, having aggravated toner goes bad.Therefore, with above-mentioned peripheral speed than being set in the scope of 105%-120%.As developer roll 11, use a kind of like this roller, it uses surface roughness tester SE-30II (Kosaka Laboratory Co., Ltd. the arithmetic average roughness Ra that product) measures (JIS B 0601-1994) satisfies following mathematic(al) representation, wherein Ra[μ m] and X[μ m] represent the average roughness Ra of developer roll 11 and the equal granularity of body of developer respectively:

[mathematic(al) representation 1]

0.33≥A/X≥0.20 ...(1)

Be used for providing wherein a kind of method of surfaceness of predetermined extent as follows to developer roll 11.At first, on the circumferential surface of metal core, form elastic layer.Then, the surface of scraping elastic layer.Then, the thickness that forms the superficial layer that constitutes developer roll 11 by roller coat, spraying, dip-coating etc. on the circumferential surface of the scraping of elastic layer is approximately the resin bed of 10 μ m.In addition, can as the material of the superficial layer that is used for developer roll 11,, replace scraping, realize required surfaceness by in resin, disperseing the particle of appropriate size to the surface of elastic layer to be formed on rough superficial layer on the whole surface.In this embodiment, using the equal granularity of body is the toner of 6 μ m.Therefore, using average surface roughness Ra is that the roller of 1.2 μ m-2.0 μ m is as developer roll 11.Method as for the equal granularity of body of measuring developer, use particle size distribution measurement equipment LS-230 (Coulter Co., the product of Ltd), it is a diffraction-type laser kind equipment, being used in combination the grain diameter measurement scope simultaneously is the liquid module of 0.04-200 μ m, is calculated the equal granularity of body of developer from what obtain based on the size-grade distribution of volume.If the A/X value of above-mentioned mathematic(al) representation (1) is not more than 0.20, can not effectively transmit toner, can not form the gratifying highdensity image of its solid black region.Therefore in addition, developer roll 11 surfacenesses are low, can not be effectively wipe attached to the toner on the periphery surface of photosensitive drums 2 and the corresponding zone of black region image from photosensitive drums 2.Therefore, the fuzzy toner that forms increases.On the other hand,, can more effectively transmit toner, improve the amount that is coated on the developer roll 11 thus if the A/X value of mathematic(al) representation (1) is not less than 0.33.Therefore, toner can not the charging fully because of friction.Therefore, uncharged toning dosage increases, and in other words, the fuzzy toner that forms increases.

Under developer roll 11, setting has the feed rolls 13 of elastic layer, and described feed rolls contacts with developer roll 11 and is rotated support.Drive feed rolls 13 according to direction (shown in the arrow B) rotation identical with the sense of rotation of developer roll 11.The effect of feed rolls 13 is to provide toner to developer roll 11, and wipes the toner on the developer roll 11 of remaining in that is not developed consumption.From giving developer roll 11 supply developers and wiping the angle that does not consume toner on developer roll 11, wish that feed rolls 13 made by sponge, perhaps constitute by metal-cored, the bristle of fibers such as rayon, nylon be placed in metal-cored on.The superficial layer of wishing feed rolls 13 at least is made of the foaming elastic material, and its hole is quasi-sovereign.The superficial layer of preferred feed rolls 13 is made of the foaming elastic material, and its hole interconnects, because feed rolls is formed by foaming substance, its hole interconnects according to the mode that forms slotted hole, can keep a large amount of toners in its superficial layer.In this embodiment, use the roller that is formed by polyurethane sponge, its hole interconnects, with this as feed rolls 13.About being used for the foaming elastic material of feed rolls 13, can use the bipeltate that forms by foaming such as foamed silastic, ethylene-propylene-diene rubbers (EPDM).But the hole of feed rolls 13 is not to interconnect, and can use a kind of foaming elastic material, and its hole is independently.About the width of the contact area between feed rolls 13 and developer roll 11,1-6mm is effective.In addition, wish that the periphery surface of feed rolls 13 has certain speed with respect to the outer surface of developer roll 11 in the contact area between feed rolls 13 and developer roll 11.With reference to figure 2, wish that the sense of rotation f of feed rolls 13 makes the outer surface of feed rolls 13 move along the direction opposite with the sense of rotation of developer roll 11 in the contact area between feed rolls 13 and developer roll 11.In this embodiment, the contact width between feed rolls 13 and developer roll 11 is set to 3mm, and the line pressure size between feed rolls 13 and developer roll 11 is 40gf/cm (0.392N/cm).In addition, during electrostatic latent image on being developed in photosensitive drums 2, apply one be applied to as the different voltage of development bias voltage on the turning axle of feed rolls 13 metal-cored.The resistance of the resilient roller 13 of Shi Yonging roughly is 10 in this embodiment ⁸Ohm, (Koobunshi KeikiCo. Ltd) roughly is 15 ° to the hardness level of Asker CSC 2.Carry one in passing, apply the development bias voltage by 15 pairs of developer rolls 11 of power supply.Recording unit also is provided with power supply 16, is used for cooperating metal-cored along toner is applied bias voltage from feed rolls 13 to the direction that developer roll 11 shifts to as the turning axle of feed rolls 13 with the feed rolls bias voltage applying device.In this embodiment, the bias voltage that imposes on feed rolls 13 is set to-250V with respect to the development bias voltage.That is to say that with respect to the potential level that imposes on developer roll 11, the voltage that imposes on feed rolls 13 is filling on the same side of normal polarity to toner, and the potential level difference between feed rolls 13 and developer roll 11 is 250V.To the process that toner is provided to developer roll 11 that made things convenient for that applies of the above-mentioned bias voltage of feed rolls 13, can obtain image density better and because the remaining toner on the photosensitive drums 2 and fuzzy amount image still less.

What be connected developer roll 11 tops is flexible adjustment scraper plate 12 as adjustment means.Regulate scraper plate 12 and formed by metal sheet (for example stainless steel or phosphor bronze), perhaps thin resin plate (for example polyamide elastomer (PAE)) forms, and its adjusting power is stable, and can reliably toner be charged as negative polarity.Regulate scraper plate 12 and be connected on the sheet metal, thereby the surface of its supported adjusting scraper plate 12 is configured to contact with the periphery surface of developer roll 11 with the free edge adjacent areas of scraper plate 12.At developer roll 11 with regulate contact pressure between the scraper plate 12 and wish in the line pressure scope at 10-45g/cm.If contact pressure is not more than 10g/cm, toner can not suitably be charged.Therefore, the fuzzy toner that forms increases, and causes recording unit to form low-quality image, and just image exists fuzzy.If contact pressure surpasses 45g/cm, the external additive in the toner separates with toner because of excessive pressure easily.In other words, toner container easily degenerates, the reduction of chargeable property.The method that is used to measure the linear contact pressure size between developer roll 11 and scraper plate 12 is as follows.That is to say, with a length of a film be 100mm, wide for 15mm, thick be that the stainless sheet steel of 30 μ m is pulled out plate as one, with another length of a film be 180mm, wide for 30mm, thick be the stainless sheet steel of 30 μ m as a clamping plate, it is doubling alongst.To pull out plate then and be inserted between the two halves of clamping plate, and clamping plate will be inserted between developer roll 11 and the adjusting scraper plate 12.Then, apply and to pull out plate under the situation that constant acting force pulls out and pull out this being pulled out plate, and use spring balance etc. to read read number (measuring unit: g) according to predetermined speed.Then with the numerical value that is obtained, or will pull out plate and pull out necessary amount of force divided by 1.5, be the line pressure size that unit is measured to be converted into g/cm.In this embodiment, the electrically conductive elastic plate that a slice is thin, the thin elastic metal sheet of a slice for example, as regulating scraper plate 12, certainly use the scraper plate of making by the thin phosphor bronze sheet of a slice, it can provide the pressure stable size, is stained with a slice polyamide elastomer (PAE) on the surface of phosphor bronze sheet.As for the contact direction of regulating scraper plate 12, it is in the other direction.That is to say, regulate scraper plate 12 and be arranged to contact, thereby with regard to the sense of rotation of developer roll 11, the free edge of regulating scraper plate 12 is on the upstream side of the contact area between two parts 11 and 12 with developer roll 11.There are not special requirement for regulating the method that scraper plate 12 is connected to the scraper plate back up pad.But, will regulate scraper plate 12 with Screw usually and be fastened firmly on the scraper plate back up pad, perhaps it is welded on the scraper plate back up pad.The surface roughness Ra of the adjusting scraper plate 12 of Shi Yonging roughly is 1 μ m in this embodiment.In this embodiment, developer roll 11 is identical with adjusting scraper plate 12 potential level; Between developer roll 11 and scraper plate 12, do not exist potential level poor, as shown in Figure 2.But, the adjusting scraper plate 12 that forms by the metal sheet to the thin plate of for example phosphor bronze applies the scraper plate bias voltage, can be so that developer roll 11 be different with adjusting scraper plate 12 potential level, with the better condition of " the solid evil mind density " that is provided for realizing higher level, and be used to prevent to form and have a fuzzy image." entity evil mind density " expression when development contrast promptly the difference between the surface potential level at the imaging region of the periphery surface of development bias voltage that imposes on developer roll and photosensitive drums maximum in, the density of the solid image that on recording medium, forms.

That is to say, imaging device among this embodiment is a kind of like this imaging device, wherein the peripheral speed of developer roll 11 is 105%-120% (just 1.05 times-1.20 times) with respect to the ratio of the peripheral speed of photosensitive drums, and the arithmetic average roughness Ra of the periphery surface of developer roll 11 satisfies mathematic(al) representation (1).Therefore, the peripheral speed by reducing developer roll 11 can be controlled degenerating of toner with respect to the ratio of the peripheral speed of photosensitive drums, realizes gratifying image density simultaneously and form clearly image just not have the image that blurs.

Imaging device among this embodiment 1 is carried out durability test, and the quantity that wherein just begins to take place the duplicate of output before the image deflects is carried out the durability test of imaging device.Therefore the machine drawing picture damage amount that the developing apparatus 4 that imaging device 1 among this embodiment is provided with is caused owing to rubbing in the contact gap of toner between photosensitive drums 2 and developer roll 11 is less, at the toner controlling party mask that degenerates advantage is arranged.In particular, when above-mentioned peripheral speed ratio is 120%, (for example uneven image density is even to cause occurring defective in the toner formation striped coating that the duplicate image is melted on the adjusting scraper plate 12 owing to toner and the developer roll 11 that brings thus will be output, blur etc.) before, the quantity of the duplicate that the imaging device 1 of this embodiment is exported be prior art developing apparatus 1.5-2.0 doubly.In other words, degenerating of developer of control makes it that a kind of like this equipment can be provided, and obviously is longer than the equipment of prior art its serviceable life, just can use more macrocyclic equipment than the equipment of prior art.

[embodiment 2]

Below, with reference to figure 3, the developing apparatus that the imaging device in another preferred embodiment of the present invention adopts is described.Developing apparatus in this embodiment and the basic structure of imaging device and operation roughly with first preferred embodiment in identical.Therefore, the Reference numeral identical with first embodiment adopted in fact having with the element of the equivalent of the element of the first embodiment identical functions and structure or its function or structure of equipment in this embodiment, and is not described in detail.This embodiment and the first embodiment difference are to use a kind of like this roller as developer roll 11, its arithmetic average roughness Ra (JIS B 0601-1994) satisfies following mathematic(al) representation, wherein Ra[μ m] and X[μ m] the expression average roughness Ra of developer roll and the equal granularity of body of developer:

A/X＜0.20 (2)

As regulating scraper plate 12, use for example scraper plate of the sheet metal formation of the thin plate of phosphor bronze.From as the power supply 14 of scraper plate bias voltage applying device to regulate scraper plate 12 apply with respect to the level of developer roll 11-bias voltage of 50V-250V.When toner scraper plate 12 applies bias voltage, be set under the situation of 240mm/s in the peripheral speed of inciting somebody to action developer roll 11 in this embodiment, the electric current of 3 μ A-7 μ A flows through between adjusting scraper plate 12 and developer roll 11.With respect to the level of developer roll 11, the level of regulating scraper plate 12 is desirably on the normal polarity same side with to the toner charging.That is to say, in this embodiment,, be on the negativity side of level of developer roll 11 so regulate the level of scraper plate 12 because the normal polarity filled with to toner is a negativity.Therefore, toner is easier of on the developer roll 11, and more difficult being attached to regulated on the scraper plate 12.Therefore, the thickness of the toner layer on developer roll 11 remains on suitable numerical value.As mentioned above, the level of expectation toner scraper plate 12 is on the negativity side of level of developer roll 11, and is not less than 50V and is not more than 250V in the level differences of regulating between scraper plate 12 and the developer roll 11.

Therefore in this embodiment, when the normal polarity of filling with to toner was positivity, the level expectation of regulating scraper plate 12 was not less than+50V and being not more than+250V than the level height of developer roll 11.

Enough little when satisfying mathematic(al) representation (2) at the numerical value of the average roughness Ra of developer roll 11, it is poorer that developer roll 11 is compared when not being such with numerical value in the average roughness Ra of developer roll 11 aspect the toner transport capacity.Therefore, be difficult to realize gratifying " filled black density " level.Therefore, when the normal polarity of filling with to toner was negativity, the level expectation of regulating scraper plate 12 was lower than the level (on its negativity side) of developer roll 11, so that realize gratifying " filled black density " level.In the situation that adopts this layout, above-mentioned electric current flows between adjusting scraper plate 12 and developer roll 11, and therefore resulting electric field has increased the toning dosage (after the toner that is adjusted in by adjusting scraper plate 12 on the developer roll 11) that is coated on the developer roll 11.In addition, under the effect of the toner on the developer roll 11, keep being pressed against on the developer roll 11 at electric field force.Therefore, although the toning dosage that is coated on the developer roll 11 increases, the fuzzy toner that forms can not increase yet.In addition, with reference to Fig. 3, in this embodiment, will during the latent electrostatic image developing on the photosensitive drums 2, apply the voltage identical to the metal core of the feed rolls 13 that keeps contacting with developing voltage with the bottom side of developer roll 11 by power supply 15.

That is to say, imaging device in this embodiment is a kind of like this imaging device, wherein the average roughness Ra of developer roll 11 satisfies mathematic(al) representation (2), and the peripheral speed of developer roll 11 with respect to the ratio of the peripheral speed of photosensitive drums 2 in the scope of 105%-120%, and by apply to regulating scraper plate 12-bias voltage of 50V--250V is (with respect to the level of developer roll 11, suppose that the normal polarity of filling with to toner is a negativity) and reduce the ratio of the peripheral speed of developer roll 11 with respect to the peripheral speed of photosensitive drums 2, know promptly not fuzzy and the gratifying image of image density thereby can control rotten the formation simultaneously of toner.

Still in this embodiment imaging device 1 is carried out durability test, wherein before image deflects begin to occur aspect the duplicate quantity of output the permanance of test imaging device.The developing apparatus that imaging device 1 was equipped with 4 in this embodiment is less aspect the damage amount that the physical shock on toner causes by the developer in the contact gap of friction between photosensitive drums 2 and developer roll 11 when using this equipment continuously.In other words, imaging device in this embodiment is favourable from the rotten aspect of control toner.In addition, the average roughness Ra of its developer roll 11 is littler.Therefore, it not only can prevent so-called film forming, and promptly toner accumulates in the groove in the circumferential surface of developer roll 11 and rests on wherein, and it has prevented that also the friction between developer roll 11 and photosensitive drums 2 from becoming excessive.Therefore, by in this embodiment imaging device 1 begin to export have be melted in owing to toner regulate on the scraper plate 12 and the duplicate of image deflects that the striped coating of the developer roll 11 that obtains with toner causes (for example the even property of uneven image density, fuzzy etc.) before serve as reasons 1.8 to 2.5 times of quantity of developing apparatus 20 outputs that constitute according to prior art of the duplicate quantity of output.In other words, this embodiment can also go bad by the control developer provides the equipment of obviously being longer than its serviceable life according to the equipment of prior art, promptly can use the equipment of longer time according to the equipment of prior art by beguine.

Next, the effect of the preferred embodiment of the present invention will be described according to the imaging device in the preferred embodiment of the present invention 1 and those imaging devices in following comparative example of the present invention and the mode that compares between those imaging devices in the test below.

[comparative example 1]

In the situation of developing apparatus in this embodiment, the peripheral speed of developer roll 11 is set at 130% with respect to the ratio of the peripheral speed of photosensitive drums 2, and this is the same in according to the developing apparatus of prior art (shown in Fig. 8) with it.In addition, the equal granularity of its body of toner is 6 μ m, and developer roll 21 its mean roughness are 1.0 μ m.Obviously mutual intrusion amount between developer roll 21 and photosensitive drums 24 is 40 μ m.Between developer roll 21 and adjusting scraper plate 22, any potential difference (PD) is not set.This developing apparatus is installed in the imaging device, and continues test, wherein prints 5000 duplicate to assess the picture quality of this equipment.This test is carried out under normal temperature and humidity (25 ℃ and 60%RH).This test result is such: make toner rotten by the friction force between developer roll 21 and photosensitive drums 24, thereby make the image that equipment forms does not have defective for example so-called " afterimage ", development striped etc." afterimage " refers to the image remainder that forms during the imaging process in front and occurs in the image of back.

[comparative example 2]

In view of the result in first comparative example, rotten in order to control the toner that causes owing to the friction force between developer roll 11 and photosensitive drums 2, the heat that produced etc., the peripheral speed that reduces developer roll 11 with comparing in first comparative example is with respect to the ratio of the peripheral speed of photosensitive drums 2.

Therefore, confirm to go bad than controlling the toner that causes owing to the friction force between developer roll 11 and photosensitive drums 2, the heat that is produced etc. by the peripheral speed that is reduced between developer roll 11 and the photosensitive drums 2.More particularly, when the imaging device that has adopted the developing apparatus in this comparative example is wherein printed the printing test of 5000 parts of duplicate, image deflects for example afterimage, development striped etc. can not appear.

But the reduction (as shown in table 1) of the peripheral speed ratio between developer roll 11 and photosensitive drums 2 has not only aggravated fuzzy formation, and it has hindered imaging device to realize gratifying " filled black density " level.Because reduce peripheral speed than having reduced the friction force between developer roll 11 and photosensitive drums 2 and therefore not only having reduced the fuzzy ability of toner but also toner gratifying to realize " filled black density " level that developer roll can not be carried q.s of forming of striking off of photosensitive drums 11, so this situation just occurs." filled black density " is the highest level of image density, and this can work as when difference between the level of the level of exposure station (luminous point) of the electrostatic image on being formed on photosensitive drums and development bias voltage exists and realizes.

With reference to table 1, adopt leucometer TC-6DS (Tokyo Denshoku Co., the product of Ltd.) to measure fuzzy quantity.As for the fuzzy formation toning dosage of measuring on photosensitive drums, pick up fuzzy formation toner on photosensitive drums by a slice Mylar band, and the whiteness of the Mylar band of blank out is compared with the whiteness that this sheet Mylar is with.Then, will be defined as the index of the fuzzy formation toning dosage on photosensitive drums in the whiteness difference between these two bands.Be not more than at 0.7 o'clock at this index, think that the fuzzy formation toning dosage on photosensitive drums is gratifying, promptly not obvious.But, if this index is not less than 0.7, then fuzzy to form toning dosage obvious, especially when using glossy paper as recording medium and/or at the imaging device that is used for imaging during as color-image forming apparatus, because fuzzy formation toner is produced by each of Y, M, C and Bk imaging station.In other words, if this index is not less than 0.7, then will form the obviously fuzzy image of appearance.Therefore as for " filled black density ", if its optical density is not less than 1.3, then the solid black areas of image seems evenly, thinks that it is gratifying being not less than 1.3 " filled black density ".But if " filled black density " is not more than 1.3, then the solid black areas of image is lower and/or inhomogeneous aspect image density.Therefore, think that it is not satisfied being not more than " filled black density " level of 1.3.That is to say, from the result who table 1, provides as can be seen, in the situation of the imaging device in this comparative example, without any comparing scope in all gratifying peripheral speed aspect blur level and " the filled black density ".

Table 1

Peripheral speed is than (%)	Blur level	Filled black density
Peripheral speed is than (%)	Blur level	Filled black density	100	1.5	0.9
105	1.1	1	100	1.5	0.9
105	1.1	1	120	0.7	1.2
135	0.6	1.3	120	0.7	1.2

[comparative example 3]

From the result second comparative example as can be seen, when aspect the peripheral speed between developer roll 11 and photosensitive drums 2 during without any difference, promptly when the peripheral speed ratio of developer roll 11 and photosensitive drums 2 be 100% therefore between developer roll 11 and photosensitive drums 2 during without any friction force, this imaging device is making us dissatisfied aspect blur level and " the filled black density " very much.Therefore, in this comparative example, think and the fuzzy formation toner on developer roll 11 is struck off by being increased in the toning dosage that applies on the developer roll 11.

That is to say,, attempt in the past to improve the ability (table 2) that developer roll 11 is carried toner by the average roughness Ra that increases developer roll 11 in order to carry the ability of toner to increase the toning dosage that is coated on the developer roll 11 by improving developer roll 11.But along with the toning dosage that is coated on the developer roll 11 increases, the toner-particle that is arranged in toner layer middle (aspect the radial direction of developer roll 11) contacts unsatisfactorily regulates scraper plate 12, thus can not be by friction charging satisfactorily.Therefore, the toner of uncharged toner and reverse charging increases.Therefore, attempt to utilize electric field force to increase and be coated in toning dosage on the developer roll 11.More particularly, with respect to the level of developer roll 11 ,-50V is applied to and regulates on the scraper plate 12 (table 2) to-scraper plate bias voltage of 250V.Therefore, make the toner on developer roll 11 keep pressing to developer roll 11 by the electric field force that acts on developer roll 11 and regulate between the scraper plate 12.Therefore, the toner layer density on developer roll 11 increases, and has increased " filled black density " thus.

Table 2

But, because the peripheral speed ratio is 100%, then between developer roll 11 and photosensitive drums 2 without any friction force.Therefore, the microcosmic spine of the circumferential surface of developer roll 11 and paddy portion can not wipe the toner on photosensitive drums 2 off.Therefore, the toner that has been transferred on circumferential surface corresponding with white space image the zone of photosensitive drums 2 can not got back on the developer roll 11.Therefore, increase the toning dosage that is coated on the developer roll 11 by bias voltage etc. being applied to regulate on the scraper plate 12.But the fuzzy toner that forms increases and increases along with the toning dosage on developer roll 11.

[test 1]

In view of the result in first to the 3rd comparative example, want that the peripheral speed by developer roll 11 is set at 120% with respect to the ratio of the peripheral speed of photosensitive drums 2, this moment, friction force acted between developer roll 11 and the photosensitive drums 2, and when regulating scraper plate 12 controls, increasing the toning dosage that is coated on the developer roll 11, wipe the fuzzy toner that forms off, so that solve fuzzy problem and realize gratifying " filled black density " level.

In this test, the equal granularity of the body of toner is 6 μ m, and the peripheral speed of developer roll 11 is 120% with respect to the ratio of the peripheral speed of photosensitive drums 2.Fig. 6 is a curve map, demonstrates average roughness Ra at the developer roll 11 that changes in 0.1 μ m-3.5 mu m range, at fuzzy generation toning dosage and the toning dosage (mg/cm on developer roll 11 on the photosensitive drums 2 ²) between relation.In the situation of solid line, vertical axis is illustrated in the fuzzy formation toning dosage (index) on the photosensitive drums 2, and in the situation of dotted line, vertical axis is illustrated in the toning dosage on the developer roll 11.Toning dosage on the developer roll 11 is relevant with " filled black density ".That is to say, be 120% o'clock at the peripheral speed ratio, can realize being not less than gratifying " filled black density " level of 1.3, as long as the toning dosage on developer roll 11 is not less than about 0.38 (mg/cm ²).

Surface roughness Ra and the pass that is coated between the toning dosage on the developer roll 11 are linear; Along with the average roughness Ra of developer roll 11 increases, be coated on the developer roll 11 toning dosage also with the proportional increase of average roughness Ra.On the other hand, it is only in certain scope, promptly fuzzy formation toning dosage on the photosensitive drums 2 and proportional linear the increasing of the toning dosage increase on developer roll 11.That is to say that the fuzzy formation toner measurer on photosensitive drums 2 has two flex points: be approximately the corresponding point of 0.9 μ m with the average roughness Ra of developer roll 11, and be approximately the corresponding point of 2.1 μ m with the average roughness Ra of developer roll 11.More particularly, average roughness Ra at developer roll 11 is approximately under the situation of 0.9 to 2.1 μ m, when about 0.9 μ m began to increase, the fuzzy formation toning dosage on photosensitive drums 2 reduced in the average roughness Ra of developer roll 11, but the toning dosage that is coated on the developer roll 11 increases.This situation is because following former thereby appearance.That is to say, be in the situation of 0.9 μ m-2.1 μ m at mean roughness, and the peripheral speed difference between photosensitive drums 2 and developer roll 11 is used for making the microcosmic spine and the paddy portion of circumferential surface of developer roll 11 can wipe the fuzzy toner that forms off.Therefore, be transferred on the photosensitive drums 2 and the toner that is attached on the circumferential surface of photosensitive drums 2 zone corresponding with the white space of image turns back on the developer roll 11 from developer roll 11.If the average roughness Ra of developer roll 11 is lower than 1.2 μ m, then developer roll 11 (the inhomogeneous circumferential surface of developer roll 11) can not be wiped the fuzzy toner that forms off, thereby makes the fuzzy toner that forms increase.In addition, developer roll 11 carries the ability of toner lower, so developer roll 11 can not be coated with the q.s toner.On the other hand, surpass 2.0 μ m in the average roughness Ra of developer roll 11, then for the toner-particle of giving in the part of the centre (at developer roll 11 in the radial direction) of toner layer, the toning dosage that is coated on the developer roll 11 is too many.Therefore, increased fuzzy formation toner.And under the excessive situation of the average surface roughness Ra of developer roll 11, the microcosmic spine of the circumferential surface of developer roll 11 and paddy portion make and form the image with undesired striped.From these results, can know and understand following thing.Promptly, suppose that the equal granularity of its body of toner is 6 μ m, the average surface roughness Ra that then expects developer roll 11 is in the scope of 1.2 μ m-2.0 μ m, because as long as it is in this scope, then developer roll 11 keeps it effectively to carry the ability of toner, thereby enable to realize being not less than 1.3 " filled black density ", and make the fuzzy toner index that forms keep below 0.7.But the average surface roughness scope of the developer roll 11 that developer roll 11 enough toner transfer efficiency amounts of maintenance and the fuzzy amount maintenance that forms toner are controlled is not limited to above-mentioned scope.In other words, it is according to the equal change of granularity of body that is used for the toner of imaging.In this test, adopting the equal granularity of its body is the toner of 6 μ m.But, only need the average surface roughness Ra of developer roll 11 to satisfy following mathematic(al) representation, wherein A[μ m] and X[μ m] represent the equal granularity of body of the average surface roughness Ra and the developer of developer roll 11 respectively:

[mathematic(al) representation 2]

0.33≥A/X≥0.2 ...(1)

For example, in the equal granularity of its body is in the situation of toner of 5 μ m, the average surface roughness Ra of developer roll 11 is desirably in the scope of 1.0 μ m-1.65 μ m, and be that the average surface roughness Ra of developer roll 11 is desirably in the scope of 1.6 μ m-2.6 μ m in the situation of toner of 8 μ m in the equal granularity of its body.As long as the average surface roughness Ra of developer roll 11 is in above-mentioned scope, then can will be transferred on the photosensitive drums 2 and the toner that is attached on the zone corresponding with the Image blank zone of photosensitive drums 2 is wiped off from developer roll 11.Table 3 demonstrates in peripheral speed that the equal change of granularity of the body of average roughness Ra that makes developer roll 11 and developer makes developer roll 11 simultaneously remains on 120% test with respect to the ratio of the peripheral speed of photosensitive drums 2, the relation between " filled black density " and the blur level.Be not less than at 1.3 o'clock in " filled black density " its optical density, think excellent (O), as in second comparative example.Fuzzy formation toning dosage (index) as on photosensitive drums 2 is not more than at 0.7 o'clock at it, thinks excellent (O), also as in second comparative example.In addition, table 3 demonstrates when thinking filled black density and the fuzzy formation toning dosage excellence (O) on photosensitive drums 2, satisfies mathematic(al) representation (1).

Table 3

Peripheral speed is than 120%

If the mean roughness R of developer roll 11 is less than 0.2 times of the equal granularity of body of toner, then developer roll 11 is carried aspect the amount of toner not enough at it.On the other hand, if the mean roughness R of developer roll 11 greater than 0.33 times of the equal granularity of body of toner, then developer roll 11 is carried aspect the amount of toner too much at it, this helps the fuzzy toning dosage that forms to increase.In addition, for the relation between the average roughness Ra of equal granularity of the body of developer and developer roll 11, the latter must be enough greatly to satisfy mathematic(al) representation (1).Otherwise developer roll 11 strikes off the toner on the zone corresponding with the Image blank zone that has been attached to photosensitive drums 2 circumferential surfaces unsatisfactorily, to reclaim it.But if the average roughness Ra of developer roll 11 is excessive with respect to the equal granularity of the body of toner, then the spine of the circumferential surface of developer roll 11 and paddy portion can not match with the particle diameter of toner dimensionally, but can carry the toner of q.s.Therefore, strike off the toner on the zone corresponding that has been attached to photosensitive drums 2 circumferential surfaces unsatisfactorily, to reclaim it with the Image blank zone.

[test 2]

In second test, the peripheral speed ratio is set at 105% to guarantee that friction force acts between developer roll 11 and the photosensitive drums 2.In addition, during the average roughness Ra that makes developer roll 11 changes in the scope of 0.1 μ m-3.5 μ m, measure at the toning dosage (index) of the fuzzy formation on the photosensitive drums 2 and be coated in toning dosage (mg/cm on the developer roll 11 ²).Provided the check result of this test in Fig. 7, wherein in the situation of solid line, vertical axis is illustrated in the fuzzy formation toning dosage (index) on the photosensitive drums 2, and in the situation of dotted line, vertical axis is illustrated in the toning dosage on the developer roll 11.Toning dosage on the developer roll 11 is relevant with " filled black density ".That is to say, be 105% o'clock at the peripheral speed ratio, as long as the toning dosage on developer roll 11 is not less than about 0.43 (mg/cm ²), just can realize being not less than gratifying " filled black density " level of 1.3.

If the toning of the fuzzy formation on photosensitive drums 2 dosage be not more than 0.7 and " filled black density " be not less than 1.3, then obtain excellent image.Therefore, in this test, as the equal granularity of its body of toner in first test is that 6 μ m and peripheral speed ratio are 105%, as long as the average roughness Ra of developer roll 11 is in the scope of 1.2 μ m-2.0 μ m, then developer roll 11 is coated with gratifying toning dosage, and the spine of the circumferential surface of developer roll 11 and paddy portion are as removing device.Therefore, the fuzzy toner that forms keeps being controlled.In this test, using the equal granularity of its body is the toner of 6 μ m.But, as long as the relation between the equal granularity of body of the mean roughness of developer roll 11 and developer satisfies following mathematic(al) representation (3), wherein A[μ m] and X[μ m] represent the equal granularity of body of the average surface roughness Ra and the developer of developer roll 11 respectively:

[mathematic(al) representation 3]

0.33≥A/X≥0.2 ...(1)

Even be 105% then at the peripheral speed ratio, resulting image " filled black density " and fuzzy aspect also be gratifying, as shown in table 3 the same, this table demonstrates the result of first test.

[test 3]

From first and second the test as can be seen, when the equal granularity of its body of toner is 6 μ m, unless the relation between the equal granularity of body of the average roughness Ra of developer roll 11 and developer satisfies following mathematic(al) representation (4), wherein A[μ m] and X[μ m] represent the equal granularity of body of the average surface roughness Ra and the developer of developer roll 11 respectively:

[mathematic(al) representation 4]

0.33≥A/X≥0.2 ...(1)

The fuzzy problem of toner increase, the problem that " filled black density " descends etc. of forming then appear.

Therefore in this test, the developer roll of A/X＜0.2 is satisfied in test.More particularly, the peripheral speed ratio is set at 105%, and to use the equal granularity of its body be that the toner of 6 μ m carries out imaging.In addition, the average roughness Ra of developer roll 11 is 0.1 μ m (A/X=0.02), and applies the scraper plate bias voltage to regulating scraper plate 12.In table 4, provided and changed " the filled black density " that obtains during the toner scraper plate bias voltage and on photosensitive drums 2, bluring the numerical value that forms toning dosage (index).In this test, the normal polarity of filling with to toner is a negativity.

As can be seen from Table 4, general-50--250V (with respect to the level of developer roll 11) bias voltage is applied to and regulates on the scraper plate 12.Therefore, the electric current of 3 μ A-7 μ A is being regulated flow between scraper plate 12 and the developer roll 11 (peripheral speed of developer roll 11 is 240mm/ second).Therefore, toner is pressed on the developer roll 11, is densified to high density thus by electric field force.In other words, on developer roll 11, be coated with more substantial toner.In addition, electric field is used for toner is pressed to developer roll 11.Therefore, although the toning dosage on developer roll 11 increases, the fuzzy toner that forms also reduces.In other words, regulating applying of scraper plate bias voltage can reduce the fuzzy toner that forms and increase " filled black density " simultaneously.Be higher than-the adjusting scraper plate bias voltage of 250V apply the further increase that can not cause " filled black density ", can not cause the fuzzy toner that forms further to reduce yet.On the contrary, because electricity, it is rotten that toner takes place, and for example external additive separates with toner-particle.Be lower than in addition ,-the adjusting scraper plate bias voltage of 50V can not effectively increase " filled black density " and reduce the fuzzy amount that forms toner.That is to say that even when the roller that satisfies A/X＜0.2 is used as developer roll 11 ,-50--250V (with respect to the level of developer roll 11) bias voltage is applied to be regulated on the scraper plate 12, can improve image density and control the fuzzy toner that forms simultaneously.In other words, this test show expection regulate the level of scraper plate 12 be in the normal polarity same side of filling with to toner on, and regulate level differences between scraper plate 12 and the developer roll 11 in the scope of 50V-250V.

Table 4

Regulate scraper plate bias voltage (V)	Blur level on the drum	Filled black density
Regulate scraper plate bias voltage (V)	Blur level on the drum	Filled black density	There is not bias voltage	0.7	0.9
-50	0.7	1.3	There is not bias voltage	0.7	0.9
-50	0.7	1.3	-100	0.5	1.5
-150	0.3	1.5	-100	0.5	1.5
-150	0.3	1.5	-200	0.3	1.5
-250	0.3	1.5	-200	0.3	1.5

This test shows that also the average roughness Ra of developer roll 11 reduces in the falcate paddy portion of the circumferential surface that can prevent the toner gathering and firmly rest on developer roll 11, and it can also prevent to produce excessive friction force between developer roll 11 and photosensitive drums 2.

[test 4]

The 4th the test in, with peripheral speed than being set at 120% to guarantee between developer roll 11 and photosensitive drums 2, having enough big friction force.Otherwise the 4th test is identical with the 3rd test, and wherein adopting the equal granularity of its body is the toner of 6 μ m, and to use its surface roughness Ra be that the developer roll of 0.1 μ m (A/X=0.02) is used as developer roll 11.On adjusting scraper plate 12, apply the scraper plate bias voltage.Provided the numerical value of " filled black density " and the fuzzy formation toning dosage (index) on photosensitive drums 2 in table 5, this is to use various adjusting scraper plate bias voltages to realize.

Table 5

Regulate scraper plate bias voltage (V)	Blur level on the drum	Filled black density
Regulate scraper plate bias voltage (V)	Blur level on the drum	Filled black density	There is not bias voltage	0.4	0.9
-50	0.4	1.4	There is not bias voltage	0.4	0.9
-50	0.4	1.4	-100	0.3	1.5
-150	0.3	1.5	-100	0.3	1.5

-200	0.1	1.5
-200	0.1	1.5	-250	0.1	1.6

Also have, the peripheral speed ratio be 120% and developer roll 11 satisfy: in this test of A/X＜0.2, to regulate the scraper plate bias voltage to remain on-fuzzy formation toning dosage on the photosensitive drums 2 is remained on be not higher than 0.7 level, and make " filled black density " keep being not less than 1.3; Thereby can obtain excellent image.

In order to summarize third and fourth test, the peripheral speed of expectation developer roll be photosensitive drums peripheral speed 1.05-1.20 doubly; A/X＜0.2; The level of regulating scraper plate with the normal polarity same side of filling with to toner (with reference to the level of developer roll) on, and at developer roll with regulate in the scope of level difference between the scraper plate at 50V-250V.That is to say, satisfy and improve imaging device aspect fuzzy formation toner that above-mentioned condition can be on photosensitive drums and " the filled black density ".

[embodiment 3]

Fig. 4 is for being removably mounted on the schematic cross sectional views of the embodiment of the handle box 30 in the imaging device according to the present invention.

Handle box 30 has developer roll 11 as reagent delivery component, as the toner scraper plate 12 of developer adjustment means, feed rolls 13 etc.Adjusting scraper plate 12 is arranged to one of them main surface and is contacted with the circumferential surface of developer roll 11.Identical with in first embodiment of developing apparatus 4 its structures in this embodiment.Handle box 30 comprises developing apparatus 4, photosensitive drums 2, charging device 3 and as the cleaning balde 8 of cleaning device, they are arranged in the plasticity supporting member integratedly, and its part constitutes used toner memory unit.

In other words, handle box 30 in this embodiment is subassemblies that above-mentioned developing apparatus 4 and being used to is handled the unit of photosensitive drums 2.Some handle boxes are not provided with cleaning device and charging device.

Therefore, any developing apparatus 4 among the embodiment can be as one of them structural detail of handle box 30 in front.Handle box 30 is removably mounted in the imaging device.Therefore, can change the whole imaging device of imaging device simply by replacing handle box 30.Therefore adopt handle box 30 to improve the property easy to maintenance of imaging device.

Fig. 5 is the synoptic diagram that has adopted the color-image forming apparatus of four handle boxes 30, and described four handle boxes 30 are Y, M, C and K handle box.Its fuzzy formation toning dosage (index) on photosensitive drums of developing apparatus in this embodiment is not more than 0.7.Therefore, though this color-image forming apparatus it the monochromatic coloured images of four of each full-colour image develop also can form not have the image that obviously blurs.Therefore, when using this color-image forming apparatus, even aspect image density, in the satisfactory and image that not have to blur, can control the damage that causes owing to the friction that in the contact area between reagent delivery component and image bearing member, occurs making color-image forming apparatus output picture rich in detail to developer.

Its frequency of utilization of black is higher than other color, and human eye can detect the fuzzy existence of black fuzzy easilier than what it can detect other color.Therefore, expect every kind of color (Y, M and C) ratio of peripheral speed and the peripheral speed of corresponding photosensitive drums 2 of developer roll 11 of developing apparatus 4 is set at 105%, and the peripheral speed of the developer roll 11 of black developing device 4 is set at 120% with respect to the ratio of the peripheral speed of development photosensitive drums 2.In other words, expect that the peripheral speed of each color development device 4 is than being set at the peripheral speed ratio that is lower than colourless developing apparatus 4.Adopt this set, can under the situation of the black text quality that does not reduce color-image forming apparatus, control fuzzy formation, and can export than by the more durable coloured image of exporting according to the color-image forming apparatus of prior art of coloured image.

By the way, in the preferred embodiment in front, developer roll 11 always keeps contacting with photosensitive drums 2.But except during developing, developer roll 11 can keep separating with photosensitive drums 2.

In addition, as the device that is used between photosensitive drums 2 and developer roll 11, providing the predetermined circle velocity ratio, can be adjusted between the gear that gear that photosensitive drums 2 is equipped with and developer roll 11 be equipped with relation at diametrically.

According to the present invention, can control owing to the rotten image deflects that cause of developer. As one of them actual effect of the present invention, the effect that can list has, the present invention can be controlled at the damage that the developer in the contact gap between reagent delivery component and image bearing member causes, the image that simultaneously output is cleaned, namely satisfactory aspect image density and do not have a fuzzy image, enable thus to provide the equipment that can use for a long time, namely at beguine aspect service life according to the longer equipment of the equipment of prior art.

Although describe the present invention with reference to disclosed structure, the present invention is not limited to given details, the application is intended to cover these modification or the variation that falls within improvement purpose or the following claim scope.

Claims

1. imaging device comprises:

Image bearing member;

2. equipment as claimed in claim 1 is characterized by, and described delivery member is arranged to contact with described reagent delivery component.

3. equipment as claimed in claim 1 also comprises the developer adjustment means, and this developer adjustment means contacts with the surface of reagent delivery component, is used for being adjusted in the amount of the developer that carries on the described reagent delivery component.

4. equipment as claimed in claim 1 is characterized by, and the degree of depth that described image bearing member is pressed in the described reagent delivery component is not less than 10 μ m and is not more than 50 μ m.

5. equipment as claimed in claim 1, it is characterized by, the shape coefficient SF-1 that is included in the toner-particle in the developer is not less than 100 and be not more than 160, and its shape coefficient SF-2 is not less than 100 and be not more than 140, and described shape coefficient SF-1 and SF-2 limit by following equation:

6. equipment as claimed in claim 1, also comprise second image bearing member and second reagent delivery component that can contact with described second image bearing member, be used for developer is carried to developing location, to be formed on electrostatic image development on described second image bearing member with developer, wherein, the ratio of the peripheral speed of described reagent delivery component and the peripheral speed of described first image bearing member is less than the ratio of peripheral speed with the peripheral speed of described second image bearing member of described second reagent delivery component.

7. equipment as claimed in claim 6 is characterized by, and the developer that is carried on the described reagent delivery component is a color developer.

8. equipment as claimed in claim 1 is characterized by, and described developer is non-magnetic single component developer.