CN101093377A - Developing apparatus - Google Patents

Abstract

An amount-of-developer regulating apparatus configured to restrict the amount of developer carried on a developer bearing member. The amount-of-developer regulating apparatus includes a flexible developer amount regulation member having a contact portion configured to contact with a developer bearing member, and first and second holding portions configured to hold the developer amount regulation member and to contact with the developer amount regulation member at further upstream and further downstream in a direction where the developer bearing member is rotationally moved than the contact portion. With a pressure distribution of the contact portion as to the developer bearing member, there are a plurality of local maximum values in the direction where the developer bearing member is rotationally moved. Thus, the apparatus can be reduced in size, and also image concentration unevenness after long-term use can be prevented.

Description

Developing apparatus

Technical field

The present invention relates to a kind of developing apparatus, it is used to adopt the imaging device of electrophotographic method for example or electrostatic recording method.

Background technology

For the developing method of the single component toner that adopts the existing developer of conduct, contact developing method and noncontact developing method use widely.Particularly, it is as follows to propose a plan: (1) adopts the contact developing method as the developer roll of the existing developer bearing member with flexible layer, (2) utilize the noncontact developing method of nonmagnetic toner, employing has the developer roll of metal sleeve or flexible layer as developer bearing member, (3) utilize the noncontact developing method of nonmagnetic toner, adopt metal sleeve as the development bearing carrier, or the like.In these developing methods, be configured to regulate the amount of developer so that single component toner has proposed several measures on aspect the developer level adjustment means that forms thin layer on the developer bearing member.

(1) employing has the contact developing method (Figure 10) of the developer roll of flexible layer

Known a kind of method wherein by as flexible roller and have that the non magnetic developer of carrying develops on the developer roll 3 of dielectric layer, and is carried out such contact with photosensitive drums 1.By the donor rollers 5 that contacts with developer roll 3 with developer replenishing developer roll 3.Donor rollers 5 comprises following function: developer is sent out from developer reservoir T, developer is sticked on the developer roll 3, and remove the developer of staying on the developer roll 3 temporarily.

Contact with developer roll 3 by developer level adjustment means 4 and carry out owing to the layer adjusting that sticks to developer on the developer roll 3 and triboelectric charge apply electric charge.In developer level adjustment means 4-c, the foliated lamellar sheet metal is adopted in suggestion, and it is supported along a side in the vertical, and the downside of its end face part contacts with developer roll 3.The developer that is coated on the developer roll 3 makes the latent electrostatic image developing that forms on photosensitive drums 1, and applies bias voltage on developer roll 3.For the method for (1), from Japanese publication No.2001-922201, obtain.

(2) utilize nonmagnetic toner and employing to comprise the noncontact developing method (Figure 11) of the developer roll of metal sleeve or flexible layer

Known a kind of method, wherein developer is gone up carrying by the development sleeve 3a that has cylindrical metal or conduction resin layer in its surface and is kept, and develops and be to be undertaken by not contacting with the surface of adjacent photosensitive drums 1.By donor rollers 5 with non magnetic developer replenishing development sleeve 3a, as (1) contact developing method.

Owing to applying electric charge with triboelectric charge, the layer adjusting that sticks to the developer on the developer roll 3 undertaken by developer level adjustment means 4 is contacted with development sleeve 3a.Comprise that in employing under the situation of developer roll of flexible layer, suggestion is used in the vertical along the foliated lamellar sheet metal of a side support, the downside of its end face part contacts with developer roll, as (1) contact-type developing method.In addition, have in employing under the situation of high-intensity development sleeve 3a, be difficult to adopt sheet metal to contact with development sleeve 3a as developer level adjustment means 4-c.Therefore, sheet metal that applies the flexible layer with certain flexibility characteristic on it or the like is adopted in suggestion.

Not only Dc bias but also AC bias are applied between development sleeve 3a and the photosensitive drums 1.The developer that has on the development sleeve 3a of developer level adjustment means 4-c flies up by this AC bias and moves back and forth between photosensitive drums 1 and non-contact type development sleeve 3a.In addition, the electrostatic latent image that is formed on the developer roll 1 is developed by the voltage that is applied to the Dc bias on the development sleeve 3a.

(3) non-contact method (Figure 12) of use magnetic color tuner and employing metal sleeve

The non-contact method of using the one-component magnetic color tuner has been known.This method uses the noncontact developing method of nonmagnetic toner identical in the following areas with (2): adopt cylindricity development sleeve 3a, undertaken because the layer adjusting and the triboelectric charge of developer apply electric charge by developer level adjustment means 4-c is contacted with development sleeve 3a.Yet,, undertaken supplying with developer by magnetic force to development sleeve 3a by magnet 7 is set in development sleeve 3a by the noncontact developing method.For method (3), from Japanese patent application publication No. No.55-18656, know.

For the noncontact developing method of (2) employing nonmagnetic toner, Dc bias and AC bias are applied between development sleeve 3a and the photosensitive drums 1, develop by noncontact.At this moment, even on development sleeve 3a, have a large amount of toners of charging performance deficiency, near magnetic pole being arranged in the part of developing, prevent that toner from unnecessarily being developed.Therefore, for the charging performance of the developer on development sleeve 3a, do not require the much the same strict control of noncontact developing method of adopting nonmagnetic toner with (2).For developer level adjustment means 4-c, by considering the contact stabilization of development sleeve 3a, rubber slab is adopted in suggestion, and this rubber slab has with the noncontact developing method of (1) nonmagnetic toner compares low contact pressure.

So far, about toning dosage adjustment means, tabular toning dosage adjustment means is known, and it is along in the vertical a side bearing thin plate flexible member, and its bottom side of facing part is contacted with developer roll.

In addition, known toning dosage adjustment means in Japanese publication No.6-250509, its two ends with tabular flexible body are fixed on the retaining member, and make the middle body of tabular flexible body contact with developer roll.

Existing developer level adjustment means, its support sheet flexible member and feasible in the face of bottom side partly contacts with developer roll has the problem that size is difficult to reduce.In case reduce the size of such toning dosage adjustment means, the distance from supporting-point to the contact point with developer roll (being free distance) reduces, at strong point place thin plate by along at a side bearing longitudinally.Therefore, the flexible constant of contact pressure increases, if even and the desired location of developer level adjustment means change very for a short time, then contact pressure changes greatly.Therefore, in order to set constant contact pressure, high-precision assembling is necessary.

In addition, produce the inequality of adhering on the supporting part that the drift of shortening thin plate flexible member can receive easily in a side along the longitudinal.Similarly, be difficult to apply in a longitudinal direction uniform contact pressure, this further makes and is difficult to realize reducing of size.

In addition, under situation about adopting, be difficult to set the desirable minimum value of contact pressure with stable manner according to the developer level adjustment means of prior art, the developer level adjustment means vertically on be easy to generate the peaked variation of contact pressure.Therefore, the extended period (service time of developing apparatus) afterwards, produce the variation of toner deterioration situation in the vertical, thus, cause such problem, that is, and after the extended period, solid picture vertically on density unevenness appears.

By adopting developer level adjustment means to form with thin layer under the situation of toner, be compressed against bottom side (surface except the edge of scraper plate) as the scraper plate of developer level adjustment means as the developer roll of developer bearing member according to known technology.Therefore, about scraper plate, developer roll with contact the pressure distribution of retained part, pressure becomes maximum in the retained part centre, and contact pressure is rendered as the para-curve pressure distribution, and the contact position place of its upstream and downstream farther apart from clamping part central authorities on the rotation direction of developer roll diminishes.

Under the situation of developer adjustment means with above-mentioned para-curve pressure distribution, in case so-called " amount of pushing of developer roll " increases, this amount of pushing is the vertical distance between the desired location of the desired location of the scraper plate before the developer roll insertion developing device assembly and the scraper plate after developer roll inserts developing device assembly, and the maximal value of contact pressure and the amount of pushing of developer roll increase pro rata.

Thereby expectation is by because the variation of the amount of pushing of the developer roll of assembling also makes the maximal value of contact pressure change.Therefore, need obtain the ideal maximum value that high assembly precision sets with stable manner the contact pressure with very little variation.

In addition, since the vibration in producing, circumferential deformation of developer roll or the like and developer roll vertically on produce under the situation that the desired location of developer level adjustment means and developer roll changes, promptly, produce under the situation that pushes quantitative changeization of looks for the developer roll of developer level adjustment means the peaked variation that produces the contact pressure of developer level adjustment means and developer roll in the vertical in the vertical.Therefore, produce the variation of toner deterioration in the vertical, especially after the extended period.Therefore, after the extended period, it is even to produce density unevenness in solid picture in a longitudinal direction.

On the other hand, in recent years, a measure that is used for reducing the power consumption of electro-photography apparatus is the power consumption that reduces in fixing.In order to be implemented in the low power consumption in the fixing, effectively reduce to be used for melting the required heat of toner, that is, reduce the molten point of toner.

Yet, being beneficial to the low temperature photographic fixing though have the toner of fusing point, the intensity of toner stress reduces.Thus, under the situation of using the one-component toning system, toner crushed and fusing under developer level adjustment means applied pressure easily.Variation about the toner deterioration situation of the peaked variation of aforesaid contact pressure becomes still more obvious.

Summary of the invention

The present invention relates to be fit to reduce the developing apparatus of size, it can stablize the contact pressure between developer level adjustment means and the developer bearing member, it can reduce the variation of the contact pressure between developer level adjustment means and developer bearing member along the longitudinal, and it is inhomogeneous to suppress image color.

Developing apparatus according to an aspect of the present invention comprises: developer bearing member, and it is configured to carrying and keeps developer, and makes the electrostatic image development that forms by developer on image bearing member; The developer level regulating device, it is configured to regulate the amount by the developer of developer bearing member carrying and maintenance.The developer level regulating device comprises: flexible developer level adjustment means, and it comprises and is configured to the contact portion that contacts with developer bearing member; First and second retaining parts, it is configured to keep the developer level adjustment means, and more contacts with the developer level adjustment means at the upstream and downstream place than contact portion on the direction that the developer bearing member rotation is moved.With the pressure distribution of the contact portion of development bearing carrier in, have a plurality of local maximums on the direction that rotatablely moves along developer bearing member.

Following description with reference to accompanying drawing and exemplary embodiment makes other advantage of the present invention more obvious.

Description of drawings

Figure 1A-1H is the synoptic diagram that illustrates according to the feature of the developer level adjustment means of example 1.

Fig. 2 is the synoptic diagram that illustrates according to the imaging device main unit of example 1.

Fig. 3 is the synoptic diagram according to the handle box of example 1.

Fig. 4 illustrates the amount of pushing of developer roll and according to the figure of the relation between the maximal value of the contact pressure of developer level adjustment means of the present invention.

Fig. 5 A and 5B are the synoptic diagram that illustrates according to the transformation of the flexible sheet material deformation of members state of developer level adjustment means of the present invention.

Fig. 6 A-6C illustrates about the flexible sheet material member of developer level adjustment means of the present invention synoptic diagram to the deformation state of the developer roll of hollow.

Fig. 7 is the synoptic diagram that illustrates according to the feature of the developer level adjustment means of example 2.

Fig. 8 is the synoptic diagram according to the developing apparatus of second embodiment that adopts example 1.

Fig. 9 A and 9B are according to the imaging device of the 3rd embodiment that adopts example 1 and the synoptic diagram of developing apparatus.

Figure 10 is the synoptic diagram according to the developing apparatus of background technology (1).

Figure 11 is the synoptic diagram according to the developing apparatus of background technology (2).

Figure 12 is the synoptic diagram according to the developing apparatus of background technology (3).

Figure 13 is the synoptic diagram that illustrates according to the developer level adjustment means of comparative example 1.

Figure 14 A and 14B are the synoptic diagram according to the developer level adjustment means of comparative example 2.

Figure 15 is the synoptic diagram that illustrates according to the developer level adjustment means of comparative example 3.

Figure 16 is the synoptic diagram according to the developer level adjustment means circumference of the developing apparatus of comparative example 4.

Figure 17 is the synoptic diagram according to the developer level adjustment means circumference of the developing apparatus of comparative example 5.

Figure 18 is the synoptic diagram according to the developer level adjustment means circumference of the developing apparatus of comparative example 6.

Figure 19 is the schematic cross sectional views of an example of image-forming apparatus according to the present invention.

Figure 20 is the figure of an example of the magnetic flux distribution of magnetic roller.

Figure 21 A and 21B are the schematic cross sectional views that illustrates according to an example of regulon of the present invention.

Figure 22 A-22C is the synoptic diagram of the forming process of the contact clamping part between adjustment means according to the present invention and development sleeve.

Figure 23 is the figure that illustrates according to a contact pressure example partly of the contact clamping part between adjustment means of the present invention and the development sleeve.

Figure 24 is the schematic cross sectional views that illustrates according to another example of regulating device of the present invention.

Figure 25 A and 25B are the schematic cross sectional views that illustrates according to another regulating device of the present invention.

Figure 26 is described in the amount of pushing of development sleeve and according to the figure of the relation between the maximal value of the contact pressure of adjustment means.

Figure 27 A and 27B are used for describing the synoptic diagram of conduct according to the transformation of the flexible sheet material deformation of members state of adjustment means of the present invention.

Figure 28 is the figure that illustrates according to the CHARGE DISTRIBUTION of the toner coating of example 5 and comparative example 12.

Figure 29 is the schematic cross sectional views that illustrates according to the regulating device of comparative example.

Figure 30 is the schematic cross sectional views that comprises according to the imaging device of the regulating device of another comparative example.

Figure 31 A and 31B are the schematic sectional view that illustrates according to the regulating device of another comparative example.

Figure 32 is the schematic cross sectional views that illustrates according to the regulating device of another comparative example.

Figure 33 is the schematic cross sectional views that illustrates according to the regulating device of another comparative example.

Embodiment

First embodiment of developing apparatus

Figure 1A-3 is that application is according to the schematic diagram of the imaging device of developing apparatus of the present invention and the detail view of describing these figure.Imaging device is for adopting the panchromatic laser printer of electrophotographic method shown in figure 2.To the overall schematic structure according to the imaging device A of the following embodiment of the invention be described below.

In imaging device A, as shown in Figure 3, be arranged in yellow, magenta, cyan and the black each by four integrally formed continuous handle box B such as charging device, developing apparatus D, cleaning device C and photosensitive drums 1, as shown in Figure 2.Each handle box B is configured to detachable with respect to the master component of imaging device.The toner image that is formed by the handle box B of each color is transferred on the intermediate transfer belt 20 of transfer device, forms full-color toner image thus.To the imaging process on each handle box B be described in detail below.

The toner image that is formed on the photosensitive drums 1 (as the image-bearing member of the handle box B of each color) is transferred on the intermediate transfer belt 20 by primary transfer roller 22y, 22m, 22c and 22k, primary transfer roller 22y, 22m, 22c and 22k be arranged in the mode that clips intermediate transfer belt 20 each color photosensitive drums 1 in the face of the position.The toner image of four colors all is transferred on the recording paper by second transfer roll 23 immediately, and second transfer roll 23 is arranged on the downstream along the moving direction of intermediate transfer belt.What note is that the remaining toner of transfer printing on intermediate transfer belt 20 is collected by intermediate transfer belt clearer 21.

Recording paper P is contained in the carton 24 of the bottom that is positioned at imaging device A, and is transmitted by paper feed roller 25 according to the printing request.The toner image that is formed on the intermediate transfer belt 20 is transferred on the paper P in second transfer roll, 23 positions.

Subsequently, the toner image on recording paper is by melting unit 26 fusings, and recording paper is discharged to the outside of imaging paper A by deliverying unit 27.

In imaging device A, upper unit and lower unit are separable, are useful on each handle box B and the transfer printing unit in four colors in upper unit, store metering paper etc. in lower unit.Therefore, the obstruction processing by being used for handling paper jam etc. and the replacing of handle box are handled, by separating and taking off upper unit and lower unit carries out above-mentioned processing.

Be noted that the imaging device A according to the embodiment of the invention uses handle box B, consider that the life-span of the handle box B of toner capacity is equivalent to 4000 paper according to A4 paper 5% printing rate conversion.

Then, according to handle box B imaging processing is described.

Fig. 3 illustrates the cut-open view of one of four handle boxes being arranged in parallel and near structure thereof.For the photosensitive drums 1 of conduct in the central authorities of imaging processing, use organic photo conductor drum 1, be coated with each bottom, carrier generation layer and carrier transfer printing layer on the external peripheral surface of the cylinder that in organic photo conductor drum 1, constitutes successively as functional film by aluminium.By imaging processing, photosensitive drums 1 is driven along the direction of arrow at a predetermined velocity by imaging device A.

Charging roller 2 as charging device makes the roller segment that is made of conductive rubber contact with photosensitive drums 1 pressure, and makes the driven rotation of its direction along arrow B.Here, as charging process, by the core body of charging roller 2, the Dc bias of-1100V is supplied with photosensitive drums 1, consequent electric charge forms uniform dark potential (Vd), and wherein the surface potential of photosensitive drums 1 reaches-550V.

With from send about the scanner unit 10 on such uniform outer surface CHARGE DISTRIBUTION surface and with the speckle patterns of the corresponding laser beam of the view data Electrifier frame, photoreceptor that shown in the arrow L Fig. 3, exposes.By the exposed portion of photosensitive-member, the electric charge on surface is eliminated by the carrier that produces layer from carrier, and its current potential reduces.For the still image (electrostatic latent image) that is formed on the photosensitive drums 1, exposed portion has bright current potential V1=-100V thus, and non-exposed portion has dark potential Vd=-550V.

Electrostatic latent image is developed by developing apparatus D, and developing apparatus D has the toner coat that is formed on as on the developer roll 3 of developer bearing member, and this developer bearing member is configured to carry the toner as having the developer of the predetermined coated weight and the quantity of electric charge.Use description to form the method for above-mentioned toner layer below, but shown in arrow c, developer roll 3 with respect to the rotation direction of photosensitive drums 1 along forwards to rotation, contact with photosensitive drums 1 simultaneously.In the present embodiment, the voltage of Dc bias-350V is applied on the developer roll 3, by the development part that contacts with photosensitive drums 1, from its potential difference (PD) part and because triboelectric charge is filled with the toner of negative electricity only sticks to bright current potential and partly go up so that electrostatic latent image is changed into true picture.That is to say that the charging polarity of toner has identical polarity with the charging polarity of electrostatic latent image, carries out opposite development.

The intermediate transfer belt 20 that contacts with the photosensitive drums 1 that is used for each handle box B is pressed onto photosensitive drums 2 by primary transfer roller 22y, 22m, 22c, 22k in the face of photosensitive drums 1.In addition, Dc bias is applied on primary transfer roller 22y, 22m, 22c and the 22y.Between primary transfer roller and photosensitive drums 1, form electric field thus.Therefore, the toner image that on photosensitive drums 1, is converted into true picture by above-mentioned pressurization with contact transfer area and receive power from electric field, and by on transfer belt 20 between being transferred in photosensitive drums 1.On the other hand, staying toner (it is not transferred on the intermediate transfer belt 20) on the photosensitive drums 1 scraper plate 6 that is cleaned wipes off then from the drum surface and falls, and be stored among the cleaning device c, this cleaning balde of being made by urethane rubber is arranged on the cleaning device c.

To the details of the developing apparatus of using first embodiment of the invention be described below.

Figure 1A shows the developing apparatus of describing later according to example 1.Developing apparatus comprises developer reservoir T and developer roll 3, and developer reservoir T is configured to store non magnetic monochromatic developer, and developer roll 3 conducts are along the developer bearing member that forwards contacts with photosensitive drums 1 simultaneously to the c rotation.In addition, developing apparatus comprises donor rollers 5 and developer level regulating device 4 and the agitation means 11 that is configured to stir toner T, donor rollers 5 is rotated in the opposite direction and contact with developer roll 3 simultaneously, and 4 conducts of developer level regulating device are configured to be adjusted in the developer level regulating device of the amount of the toner on the developer roll 3.

Now, in this example, it is the flexible roller of 12mm that developer roll 3 adopts diameter, and the conductive flexible layer of 3mm is formed on the core body that its outer dia is 6mm therein, and the volume resistance value of this flexible layer is 10 ⁶Ω m.Being noted that can be provided with to have on flexible roller superficial layer has electric charge to apply coating of function etc. to developer.In this example, in order to contact with stable manner and photosensitive drums 1 flexibility, the hardness of flexible layer 1 is 45 ° of JIS-A, and the skin hardness of developer roll 3 depends on the particle diameter of the toner that uses.But should on 10 average hardness, have the rugosity of 3 μ m-15 μ mRz.If the toner-particle that uses has the average external volume particle diameter of 6 μ m, its 10 desirable average boldness will be at 5 μ m-12 μ mRz.10 average boldness Rz adopt the definition of being stipulated by JIS B 0601, about its measurement, use the surface roughness detecting device of being produced by Kosaka Laboratory " SE-30H ".

In addition, for donor rollers 5, in this example, having adopted its outer dia is the flexible sponge roller of 16mm, and its isocyanurate foam by the 5.5mm with relatively low hardness forms, and externally diameter is to have the foaming framed structure on the core body of 5mm.Donor rollers 5 is made of interconnected porous foam, contacts with developer roll 3 thus and does not apply excess pressure thereon.Then, utilize and on developer roll 3, apply toner, and wipe the remaining toner that do not use when developing off in the suitable unevenness on the foam surface.Porous structure with scraping performance is not limited to be formed by isocyanurate foam; But can use wherein silicone rubber or ethylene-propylene-diene rubber blistered rubbers such as (EPDM rubber).

Developer level adjustment means 4 is arranged on the downstream of the surface in contact between donor rollers 5 and the developer roll 3 on developer roll sense of rotation (direction rotatablely moves) c, and is configured to contact with developer roll 3, and regulates the developer level by developer roll 3 carryings.Developer level regulating device 4 comprises the developer level adjustment means that contacts with developer roll 3 and is configured to keep the retaining part of developer level adjustment means.

Developer level regulating device 4 is controlled at the coated weight of the toner on the developer roll 3 to scheduled volume, and the control quantity of electric charge is to the scheduled volume that is adapted at developing on the photosensitive drums 1.Describe developer level regulating device 4 in detail according to example that describes below and comparative example.

Second embodiment of developing apparatus

Fig. 8 is the cut-open view of conduct according to the developing apparatus of second embodiment of the invention.In the present embodiment, above-mentioned developing apparatus is applied to panchromatic laser printer, but except above-mentioned developing apparatus, the structural system of the structure of imaging device and first embodiment.With omitting the description of the aspect identical, difference is only described with first embodiment.In the present embodiment, be arranged to as the development sleeve 3a of developer bearing member and face photosensitive drums, thereby the gap between development sleeve 3a and photosensitive drums is 300 μ m, and the non-magnetic mono-component toner that carries on development sleeve 3a is developed with the noncontact direction on photosensitive drum surface.

Particularly, shown in arrow c, development sleeve 3a with photosensitive drums 1 along forwards to rotation.The AC bias of the square waveform of the Dc bias of-350V and 2400Hz and 1600Vpp is applied to development sleeve 3a.In first embodiment, on photosensitive drums 1, form the electrostatic latent image of dark potential Vd=-550V and bright current potential V1=-100V.Utilize AC bias by flying and move back and forth, on photosensitive drums 1, form toner image at the magnetic color tuner that is subjected to the negative pole triboelectric charge on the development sleeve 3a in photosensitive drums 1 with between near the development section the development sleeve 3a divides.

The 3rd embodiment of developing apparatus

Fig. 9 A and 9B illustrate the schematic diagram that adopts the imaging device of developing apparatus of the present invention according to the 3rd embodiment.Fig. 9 A is that Fig. 9 B is the cut-open view that is used for the developing apparatus of monochromatic laser printer about the cut-open view as the one-component laser printer master component of imaging device.

In the present embodiment, the metal sleeve that has applied electroconductive resin is used as the development sleeve 3a of developer bearing member, is provided with magnetic roller 7, and it is positioned at the fixed magnetic field that connects the 3a inboard that develops as predetermined polarity and forms member.Magnetic color tuner in developer reservoir is pulled out by the magnetic force of magnetic roller 7 and towards the surface adhesion of development sleeve 3a.Stick to the rotational conveyance of the lip-deep magnetic color tuner quilt of development sleeve 3a along the development sleeve 3a of direction shown in the arrow c.Yet, when by the time with part that developer level adjustment means 4 contacts, under pressure, stand frictional electrification and regulate through layer after form the toner coating that charges.

In the present embodiment, the gap 300 μ m at place, approximated position remain between development sleeve 3a and the photosensitive drums 1.In addition ,-AC bias of the Dc bias of 350V and the square waveform of 2400Hz and 1600Vpp is applied to development sleeve 3a.With the first embodiment system, on photosensitive drums 1, form the electrostatic latent image of Vd=-550V and V1=-100V.Yet, utilize AC bias by flying and move back and forth at the magnetic color tuner through the negative pole frictional electrification on the development sleeve 3a, on photosensitive drums 1, form toner image at the magnetic color tuner through the negative pole frictional electrification on the development sleeve 3a in photosensitive drums 1 with between near the development section the development sleeve 3a divides.Be noted that the magnetic roller in development sleeve 3a has near the magnetic pole that is arranged on developing partly.By present embodiment, the toner that can have improper electric charge by the magnetic force inhibition that has 800G (Gauss) on the surface of development sleeve 3a flies to dark potential Vd part mistakenly, and can not control like this with above-mentioned potential setting.

Example and comparative example

The example and the comparative example of developer level regulating device will be described below.

Example 1

With the developer level regulating device of describing about this example of member 4.Figure 1B is illustrated in the state of the developer level regulating device 4 that predetermined use location (precalculated position of developing) keeps with U-shaped (not use location state) before locating to contact with developer roll 3.In addition, Fig. 1 C illustrates and is in the precalculated position and is pressing under the state of developer roll 3 toner quantity regulating device 4 according to this example with predetermined push-on force.Shown in Figure 1B, the developer level regulating device 4 of this example comprises as the flexible sheet material member 40 of developer level adjustment means with as the sheet material retaining member 42 that constitutes the retaining part that keeps the developer level adjustment means.Flexible sheet material member 40 is in wherein not fix with respect to sheet material retaining member 42 and for example adheres to and similar not stationary state.Now, flexible layer member 40 is by the crooked U-shaped that forms on the direction of motion of developer roll.Flexible sheet material member 40 is by crooked along the longitudinal, so that have identical with Fig. 1 C substantially shape.Flexible sheet material member 40 vertically be direction perpendicular to the space of Figure 1B and Fig. 1 C.

At this moment, elastic force F-1 acts on the flexible sheet material member 40, and wherein flexible sheet material member 40 is attempted from bearing crooked state restoration along the longitudinal.Therefore, as under pressure, contacting with the flexible sheet material supporting part 48 of the recessed inwall of sheet material retaining member 42 along second contact portion 47 on the surface at the two ends of horizontal (direction of motion of developer roll) of flexible sheet material member 40, and flexible sheet material member 40 is kept with steady state (SS) by recessed sheet material retaining member 42, even without being glued to another element or by its supporting.In addition, flexible sheet material member 40 receives the pressure F-2 from developer roll 3 at first contact portion, 46 places that flexible sheet material member 40 contacts with developer roll 3, thereby remains on steady state (SS) by elastic force.In addition, the end 49 of flexible sheet material member contacts with sheet material retaining member 42 by receive pressure F-2 at first contact portion, 46 places, and the part of flexible sheet material member 46 is adjusted to the precalculated position thus.Be noted that second contact portion 47 is arranged on upstream and downstream with respect to first contact portion 46 on the direction that developer roll rotates.

For example 1, as flexible sheet material member 40, adopted the urethane rubber of 70 ° of hardness, and the above-mentioned sheet element with 0.4mm thickness and 12.5mm lateral length is received in the recess of the retaining member 42 with 5.0mm width with JIS-A.Therefore, form U-shaped.We think that the contact condition for flexible sheet material member 40 and developer roll 3 is the amount that will be pressed into, promptly being at the apical position (position of the middle body of U-shaped) of flexible layer member 40 under the situation that developer roll 3 is not provided and the imaginary lap of the surface location (apical position of flexible sheet material member 40) of developer roll 3 under the situation of developer roll 3 is set in the normal position, is to be set at 20Kpa by the amount that will be pressed into is set at 0.8mm.

For sheet material retaining member 42, can use polystyrene resin, ABS resin, polycarbonate resin etc.In addition, sheet material retaining member 42 by with the integrally moulded part that forms the frame unit that forms developing apparatus of the frame unit of developing apparatus.

The universal measurement method of contact pressure is the pressure transducer (for example, the pressure-sensitive film made of Fuji Film Corporation etc.) for the fine sheet shape.For present embodiment, contact pressure is low, and is difficult to use the UP sensor measurement.Therefore, three stacked together measurements of hard formation H of the SUS304 stainless steel material of the measurement of contact pressure by will having 20 μ m, be inserted into the contact portion between developer level adjustment means and developer roll 3, extract thin plate along the rectilinear direction of contact from the central authorities of surface of contact with spring balance, and measure its pulling force.Thus, under the situation that applies known load on the means of pressure measurement, the measured value of contact pressure obtains from trial value and the contact width that obtains from pull out pressure survey.

Now, in the pressure distribution in the contact clamping part of the contact area of conduct between developer roll 3 and flexible sheet material member 40 shown in Fig. 1 G.For this example, the upstream and downstream place on the rotation direction of developer roll 3 has the maximal value of a plurality of contact pressures, forms to comprise the peaked pressure distribution of two contact pressures, so that have low contact pressure zone (minimum value) therebetween.

Measure for pressure distribution, the variation of contact pressure is by adopting strainmeter as electric signal measurement.Particularly, the strainmeter of being made by Kyowa Electronic Instruments Co.Ltd. " KFG-02-120 " is connected in the hole that is arranged in the hollow acrylic acid roller that has with developer roll 3 same diameter.At this moment, the top of acrylic acid resin base portion is connected so that from the outstanding 0.1-0.3mm in the surface of acrylic acid roller.In addition, the lead of strainmeter is extracted the end of acrylic acid roller from hollow space, make this roller to rotate thus.In case the acrylic acid roller that is connected with strainmeter is connected to contact and to be rotated with developer level adjustment means 4, the top of the resin base portion of strainmeter is owing to the contact pressure of regulating parts 4 receptions from developer level is out of shape.Therefore, the variation in contact pressure can be measured at the electric signal of the variation of the dependent variable of strainmeter self by conduct.At this moment, in order to reduce the noise of electric signal, except the developer level adjustment means, the member that contacts with developer roll 3 is all dismantled.Be noted that " PCD-300A " that made by Kyowa E1ectronic Ins trumentsCo.Ltd. is used to measure electric signal.

Utilize this example to be described as the reason of what a plurality of contact peak value of formation in the clamping part internal pressure of developer level adjustment means distributes below.

In case developer roll 3 further is pressed into respect to the flexible layer member 40 with U-shaped supporting (developer roll 3 moves upward in Figure 1B), flexible sheet material member 40 forms space 8 in the U-shaped middle body flexible part office contacts with developer roll 3.At this moment, flexible portion 40 distortion form elastic force thus, and form the contact pressure that is used for regulating toning dosage on developer rolls 3.Shown in Figure 1B, flexible sheet material member 40 receives the pressure F-2 from developer roll 3 at first contact portion, 46 places.

Then, being developed roller 3 by first contact portion 46 pushes, second contact portion 47 as the end face of two ends of flexible layer member 40 is tending towards launching along the identical direction of elastic force F-1, is tending towards being bent to from flexible board member 40 state restoration of U-shaped like this.Yet this trend is regulated by the retaining part 48 of the recessed inwall of sheet material retaining member 42.

Now, we consider that in Fig. 1 D, 1E and 1F, arch section is in flexible board member 40 by under the state with the U-shaped supporting.When developer roll 3 moved upward, flexible board part 40 changed to state shown in Fig. 1 D, 1E and 1F successively from the state shown in Figure 1B.Arch section is outwards not outstanding from the framework that is illustrated by the broken lines usually.Reason is the expansion of two ends of sheet material retaining part 48 adjusting flexible sheet materials 40.The width W of the framework that is illustrated by the broken lines is approximately the recess width of the recessed portion of sheet material retaining part 48, and is constant.In addition, be roughly from the end of the recessed outer wall of sheet material retaining member 42 to the distance on the surface of developer roll 3 by the height H of the framework shown in the dotted line, but its amount of pushing along with developer roll 3 increases and reduces.That is to say that in Figure 1B, when developing cell 3 moved upward, the distance H between the surface of the bottom of the inwall of the recess of sheet material retaining member 42 part and developer roll 3 reduced.On the other hand, the length of the arch section of the flexible sheet material member 40 that obtains in Fig. 1 D is considered to keep constant, and the variation on the frame size no matter shown by dashed lines.

Shown in Fig. 1 E, developer roll 3 with respect to the little situation of the amount of pushing of flexible sheet material member 40 under, flexible sheet material member 40 is developed roller 3 and pushes, and the length of arch section can keep constant by making 40 distortion of flexible sheet material member, is the space S of dash area to enter.

Then, as shown in Fig. 1 of this example F, surpass under the situation of scheduled volume, for the space S of dash area diminishes in the amount of pushing of developer roll 3.Therefore, make the length of arch section roughly keep constant by the middle body that makes arc towards 8 distortion of U-shaped hollow space.At this moment, the compressive load that is produced by the reacting force that produces from flexible sheet material supporting part 48 acts on the arch section of flexible sheet material part 40.In the centre of the arch section of sheet element, compressive load surpasses the limit load that fold occurs, and contacts with developer roll 3 under the state of fold occurring.That is to say that in Fig. 1 F, the middle body of flexible sheet material member 40 contacts with developer roll 3 under the state of upwards distortion.Therefore, shown in Fig. 1 C, in the contact clamping part between developer roll 3 and flexible sheet material member 40, contact area A1 is present in contact clamping part upstream portion, contact pressure is low in regional A2, and contact clamping part middle body appears and is present in " flaccid part " 7, and contact area A3 is present in contact clamping subordinate and swims part.In addition, shown in Fig. 1 G, pressure distribution with contact clamping part of this spline structure presents two peak Distribution, and it is included in the maximal value of the contact pressure of the upstream and downstream that contacts clamping part, and in the low contact pressure zone (minimum value) that contacts clamping part central portion office.

In this example, flexible sheet material member 40 by with respect to the developer roll travel direction vertically on crooked flexible sheet material member 40 form the developer level regulating device of U-shaped.

As the modification of example, the structure shown in Fig. 1 H also is included in the identical advantage of above-mentioned example.Particularly, flexible sheet material member 40 is not with U-shaped but is supported so that the cardinal principle with curvature is L shaped.Downstream on the rotation direction of developer roll 3, as mentioned above, the elastic force F-1 that produces owing to crooked flexible sheet material member 40 acts in second contact portion 47 on the flexible sheet material supporting part 48 of recessed inwall of sheet material retaining member 42.In addition, the upstream on the sense of rotation of developer roll 3 keeps flexible sheet material member 40 by sticking on the sheet material retaining member 42, and does not as above adopt elastic force like that.In such modification, the amount of pushing at developer roll 3 surpasses under the situation of scheduled volume, contact clamping part between developer roll 3 and flexible sheet material member 40, contact area A1 is present in contact clamping part upstream portion, contact pressure is low among the A2 of zone, contact clamping part central authorities appear and are present in " flaccid part " 7, and contact area A3 swims part contact clamping subordinate.Pressure distribution with contact clamping part of this spline structure, shown in Fig. 1 G, present two surge pressures and distribute, it is included in the maximal value of the contact pressure of the upstream and downstream that contacts clamping part, and in the low contact pressure zone (minimum value) that contacts clamping part central portion office.

Be noted that in the example in Fig. 1 C that flexible sheet material member 40 can be fixed at least one position in sheet material retaining member 48, the second contact portions 47 as upstream side, second contact portion, 47 another positions are as the downstream.

Example 2

To the developer level regulating device 4 of this example of member be described.This example that is applied to according to the developing apparatus of first embodiment shown in Figure 7.Comprise seamless flexible pipe member 41 and guarantee and hold member 45 according to the developer level regulating device 4 of this example, guarantee and hold member 45 as can holding tube being concave shape and in the face of the retaining part of developer roll 3.

In this example, flexible pipe member 41 adopts the silicones of 60 ° of hardness with outer dia 5mm and thickness 0.5mm and JIS-A, and flexible sheet material member 41 is held the recessed portion of member 45 and kept by having guaranteeing of width 5.2mm.Contact condition between the surface of developer level adjusting parts (flexible pipe member) 41 and developer roll 3 is as follows at this moment.That is to say, the amount of pushing is set at 20Kpa by contact pressure and is set at 0.8mm, and it is as at the apical position of developer level adjustment means under the situation that developer roll 3 is not set with at place, use location usually the imaginary lap of the distance between the developer roll 3 under the situation of developer roll 3 being set.

As the pressure distribution in developer roll 3 at this moment and the clamping part that flexible pipe member 41 contacts, formation comprises two peaked pressure distribution of contact pressure, it comprises the maximal value in the contact pressure of the upstream and downstream of the rotation direction c of developer roll 3 as example 1, and comprises lower pressure region therebetween.

With the developer level regulating device of describing according to this example 14.Be applied to according to this comparative example of the developing apparatus of first embodiment shown in Figure 13.Except the amount of pushing of developer roll 3 for the developer level regulating device is set to the 0.3mm, similar with the developer level regulating device of in example 1, describing 4 basically according to the toner quantity regulating device 4 of this example.Utilize the setting of the above-mentioned amount of pushing to be difficult to obtain being enough to make the toner on developer roll 3 to be reduced to the necessary contact pressure of thin layer.In this comparative example, adopt than in the example 1 as the flexible sheet material member 40 of developer level adjustment means thicker sheet material realize suitable contact pressure.Particularly, flexible sheet material member 40 adopts that to have thickness 1.0 and JIS-A hardness be 70 ° urethane rubber.The flexible sheet material member not being applied under the situation of power, is 12.5mm in its length transversely, and the flexible layer member is kept by the recessed portion with width 5.0mm of sheet material retaining member 42, forms U-shaped thus.

Flexible sheet material member 40 according to comparative example has than sheet material thicker in the example 1, thereby its elastic force is bigger.In addition, developer roll does not have its thickness big with respect to the amount of pushing of sheet element 40.Therefore, the flexible sheet material member 40 that keeps with U-shaped contacts with the surface of developer roll 3 under the almost indeclinable state of the curvature of curved surface.Under these circumstances, the fold (middle body of flexible sheet material does not separate with developer roll) that flexible sheet material member 40 do not occur, thereby with the pressure distribution of the contact site office of developer roll 3 in, only form a maximal value, this maximal value makes the contact pressure of contact clamping part middle body reach maximum.

Be noted that at the open disclosed tabular flexible member of text No.6-250509 of Jap.P., in this comparative example 1, in pressure distribution, look only to form a maximal value the developer level adjustment means.

Comparative example 2

With the developer level regulating device of describing according to this comparative example.This comparative example that is applied to according to the developing apparatus of first example shown in Figure 14.Identical with example 1, comprise flexible sheet material member 40 and sheet material retaining member 42 according to the developer level regulating device of this comparative example as the developer level adjustment means.Yet, be with example 1 difference, when keeping flexible layer member 40 to be the U-shaped formula, be not adjusted in the side of two ends transversely of flexible sheet material member.Flexible sheet material member 40 is by transversely (direction that the developer roll rotates) maintenance of two end faces.State when Figure 14 A illustrates developer roll 3 and is pushed into flexible sheet material member 40 with U-shaped supporting.Flexible sheet material member 40 contacts with developer roll 3 in the central portion office with the U-shaped on the flexible portion of hollow state.Under the situation of this spline structure, sheet material retaining member 42 is not regulated recessed portion, but regulates the side, two ends of flexible sheet material member 40, thereby even the amount of pushing of developer roll 3 increases, flexible sheet material member 40 launches on the direction perpendicular to pressure F-2.Therefore, even in as example under the situation of the amount of pushing of identical developer roll 3, prevent to produce the fold of flexible sheet material member, with the pressure distribution of the contact portion of developer roll 3 in, only form a maximal value of the contact pressure maximum that makes contact clamping part middle body.

In addition, as with comparative example 2 similar structures, a developing apparatus is disclosed in Japanese publication No.11-265115.

Comparative example 3

With the developer level regulating device of describing according to this comparative example.Developer level regulating device according to this comparative example shown in Figure 15 is by being fixed on supporting metal sheets on the developer reservoir at side support sheet shape flexible member 490 along the longitudinal, for example phosphor bronze sheet, corrosion resistant plate and similarly.The bottom side in the face of part as the lamellar flexible member 490 of developer level regulating device contacts with developer roll 3.In this comparative example, the iron plate of adopting thickness 1.2mm is as supporting metal sheets, and thickness is that the phosphor bronze sheet of 120 μ m is used as lamellar flexible member 490, supporting metal sheets is sticked on the lamellar flexible member 490 thus.From supporting part along lamellar flexible member 490 vertically on a side to the distance of the contact portion of developer roll 3, promptly so-called free distance is 14mm, the amount of pushing of 3 pairs of lamellar flexible members 490 of developer roll is 1.5mm.In addition, in such structure, with the pressure distribution of the contact portion of developer roll 3 in have only a maximal value, this maximal value makes the contact pressure maximum of contact clamping part middle body.

Comparative example 4

With the developer level regulating device of describing according to this comparative example shown in Figure 16.Developer level regulating device according to this comparative example comprises scraper plate 460 and pliable pressure unit 471, scraper plate 460 is as the developer level adjustment means that is made of rigid member, its circumferential surface with developer roll 3 contacts, and pliable pressure unit 471 is configured to push the one-sided of scraper plate 460 along the direction of the circumferential surface that presses developer roll 3.The scraper plate 460 that is made of rigid member comprises the contact recessed portion 461 that has with in the identical curvature of the circumferential surface of its single developer roll of surveying 3.

Thus, contacting in the clamping part of developer roll 3 and adjustment means, the whole side of contact recessed portion 461 and the circumferential surface of developer roll 3 contact substantially uniformly.In addition, in the pressure distribution of the contact clamping part with this spline structure, only form a maximal value, this maximal value makes the contact pressure maximum of contact clamping part middle body.In addition, as with structure like this example class, a developing apparatus is disclosed in Japanese publication No.9-34247.

Comparative example 5

With the developer level regulating device of describing according to this comparative example.Shown in Figure 17 according to the developer level regulating device of this comparative example along side support sheet shape flexible member phosphor bronze sheet etc. for example in the vertical.Lamellar flexible member comprises first cockscomb 17 and second cockscomb 21, this is in two positions and developer roll 3 contacting structure, first cockscomb 17 makes its downside of facing part contact with developer roll 3, and second cockscomb 21 is with respect to the sense of rotation C of developer roll 3 downstream at first cockscomb.According to this structure, the contact portion of each in developer roll 3 and first scraper plate 17 and second scraper plate is included in each clamping part central portion office and forms a peaked pressure distribution.

In addition, as with structure like this example class, a kind of developing apparatus is disclosed in Japanese publication No.6-95484.

Comparative example 6

Shown in Figure 16 according to developer level regulating device of the present invention.The cockscomb 3 that contacts with developer roll 3 is included in the arc recessed portion 24 of contact site office, and it is the structure of the radius of r and recessed portion 24 relation of satisfied 0＜R≤r during for R for the radius when hypothesis developer roll 3.At this moment, two marginal portions of the arc recessed portion 24 of sheet metal 23 contact with developer roll 3.Here, cockscomb is a rigid member, and is considered to inflexibility.

In such structure, the contact clamping part between developer roll 3 and cockscomb 23 comprises: the first edge contact part, and it is at the upstream end of contact clamping part, for contacting the zone that the clamping part middle body contacts with developer roll 3; The second edge contact part is in the downstream of contact clamping part.Become according to the pressure distribution of the contact clamping part of this comparative example and to comprise two peaked pressure distribution, the zone of pressure does not appear in its central authorities that are included in the contact clamping part, and is included in the precipitous surge pressure on first edge contact part and second edge contact part.

In addition, as with structure like this example class, a kind of developing apparatus is disclosed in Japanese publication No.6-5-95484.

Example 3 and 4

This example 3 and 4 is such example, wherein is applied in the developing apparatus according to second embodiment and the 3rd embodiment according to the developer level regulating device of example 1.

Comparative example 7

This comparative example 7 is such example, wherein is applied in the developing apparatus according to second embodiment according to the developer level regulating device of comparative example 3.

Comparative example 8

This comparative example is such example, and the developer level regulating device that wherein describes below is applied in the developing apparatus according to the 3rd embodiment.According to the developer level regulating device of this comparative example along in the vertical a side at the supporting metal sheets upper support polyurethane rubber that is fixed to developer reservoir etc., and its downside of facing part is contacted with development sleeve.In this comparative example, the iron plate with thickness 1.2mm is used as supporting metal sheets, and the polyurethane rubber slab with thickness 0.9mm is adhered on the supporting metal sheets as the developer level adjustment means.From along the supporting part of the side longitudinally of polyurethane rubber slab to the distance of the contact portion of development sleeve, that is, so-called free distance is 6.5mm, and development sleeve is 3.1mm to the amount of pushing of polyurethane rubber.In addition, in such structure, with the contact portion of development sleeve in pressure distribution in only form a maximal value, this maximal value makes the contact pressure of contact clamping part middle body reach maximum.

The evaluation method that is used for each example and comparative example

A) when reducing the evaluation of size and cost, provide precision to set predetermined pressure.

C: when carrying out size when reducing, require high precision to set predetermined pressure, this increases cost.

A: when carrying out size when reducing, do not require high precision to set predetermined pressure, this does not increase cost.

B) after durability test, vertically image color is inhomogeneous.

Whether the solid picture that prints black by output on whole surface carries out picture appraisal, and consider to have on vertical (the laser main scanning direction) of developer level regulating device density unevenness even.

C: it is inhomogeneous to observe vertical image color.

A: it is inhomogeneous not observe vertical image color.

After 4000 recording charts of test printing, carry out the inhomogeneous evaluation of vertical image color.Carry out test printing by the paper with horizontal document image of 5% picture rate without interruption.

C) because the image color of the vestige of pressurization is inhomogeneous

Estimate out the even property of density unevenness, this unevenness be in developer roll cycle period since the variation of local shape for example the recess of developer roll produce.Draw such evaluation, wherein consider processing speed and the peripheral speed ratio between photosensitive drums and developer roll simultaneously, calculate the development cycle, propose image error thus with same period.Even the size of image error is according to the size of the recess of developer roll and difference, length on laser sub scanning direction (direction that developer roll rotates) is approximately 1-2mm, and the length on laser main scanning direction (longitudinal direction of developer level regulating device) strides across whole zone.In this evaluation, used by on whole surface, printing the solid picture of black and the two class images that half tone image constitutes.Half tone image is meant streaky pattern, wherein writes down a line on main scanning direction, and a line thereafter is not recorded, and represents shadow tone concentration on the whole.

Whether there is image error to estimate by observing with following standard.

C: two types solid picture and half tone image all comprise image error.

B: solid picture comprises image error, but half tone image does not comprise image error.

A: two types solid picture and half tone image all do not comprise image error.

Be noted that and in this evaluation, used developing apparatus that it was in standard temperature and standard relative humidity environment (23 and 50%) following ten months.

D) ghost image

Make such picture appraisal, wherein go up the spot that forms about 25mm in image apex part (first lap of developer roll rotation), second or the concentration difference of the spot shape that more on half tone image, occurs in the developer roll rotation of ringlet be evaluated as ghost image.In addition, consider processing speed and the peripheral speed ratio between developer roll and development sleeve etc. simultaneously, calculate the development cycle exactly, and obtain this round-robin image error.

Whether there is image error to estimate by observing in order to following standard.

C: observe ghost image

A: do not observe ghost image.

When printing 100 paper, carry out this evaluation.

E) spot unevenness

The solid picture of wherein printing black by output on whole surface carries out picture appraisal, and the spot unevenness that produces in nonspecific circle is considered to image error.

Whether there is image error to estimate by considering to observe with following standard.

C: it is inhomogeneous to observe spot.

A: it is inhomogeneous not observe spot.

When at first printing to 100 paper, estimate.

Evaluation result

Evaluation result about example and comparative example is summarized in as in the following table 1

(table 1)

Example and comparative example	A) precision when reducing size and cost	B) vertical image color unevenness after Validity Test	C) the image color unevenness that forms by pressurization	D) ghost image	E) spot is inhomogeneous
						Example 1	A	A	A	A	A
Example 2	A	A	A	A	C

Comparative example 1	C	C	C	A	A
						Comparative example 2	C	C	B	A	A
Comparative example 3	C	C	C	A	A
						Comparative example 4	C	C	C	A	A
Comparative example 5	C	C	C	A	A
						Comparative example 6	C	C	C	A	A
Example 3	A	A	A	A	A
						Comparative example 7	C	C	A	A	A
Example 4	A	A	A	A	A
						Comparative example 8	C	C	A	C	A

Advantage with respect to conventional art

At first, with the advantage of describing about being the comparative example of scraping tabular toner amount adjustment means of general conventional art.Particularly, will describe about example 1,3 and 4 and comparative example 3,7 and 8.

A) precision when reducing size and cost

Comparative example 3,7 and 8 the tabular developer level adjustment means of scraping for general conventional art, but comprise the problem that is difficult to reduce size.Like this scrape the flexible member of tabular developer level adjustment means along in the vertical a side bearing thin sheet form, and its downside of facing part is contacted with developer roll 3.In these comparative examples, in case reduce size, from shortening to distance (being drift) with the contact point of developer roll 3 along the supporting-point of the thin plate of in the vertical a side bearing.

Therefore, the variation (being spring constant) in the contact pressure of the amount of pushing of developer roll 3 increases.

Now, Fig. 4 shows the relation between the maximal value of the amount of pushing of 3 pairs of developer level adjustment means of developer roll and contact pressure.In having the developer level adjustment means of traditional structure, become peaked position for contacting the clamping part middle body in contact pressure with developer roll 3.At this moment, difference although tilt according to the spring constant of each structure is to the linear increase of maximal value of the contact pressure of the amount of pushing of developer roll 3.

Therefore, in having the developer level adjustment means of traditional structure, the maximal value of contact pressure changes along with the variation of desired location.For scraping tabular developer level adjustment means, in case reduce size, the spring constant of contact pressure increases, and needs high assembly precision thus.

On the other hand, in the developer level adjustment means according to this example 1,3 and 4, as shown in the figure, have such zone, that is, developer roll 3 does not have to change pro rata with the amount of pushing of developer roll 3.Therefore, even measure existing error pushing of developer roll 3, the maximal value of contact pressure also is not easy to change.In other words, provide high-precision assembling, can stationary mode set the ideal maximum value of contact pressure even without necessity.Below to why existing such zone to be described, in this zone, do not change pro rata with the amount of pushing of developer roll 1 with the maximal value of the contact pressure of developer roll 3.

In the description of Fig. 1 of this example 1 D, 1E and 1F, the contact structures between developer level regulating device and developer roll 3 have been described.Describe according to these, surpass under the situation of scheduled volume, forms " relaxing " part by the fold that in contact clamping part middle body, occurs, thereby reduce in the contact pressure that contacts the clamping part middle body in the amount of pushing of developer roll 3.That is to say that to 1e, flexible sheet material member 40 is away from developer roll 3 as Fig. 1 f, the contact pressure at contact clamping part middle body reduces thus.Thus, the pressure distribution at the contact clamping part comprises two maximal values.

Fig. 5 A illustrates the transformation along with the distortion sheet material of the increase flexible sheet material member 40 of the amount of pushing of developer roll 3.The amount of pushing of developer roll 3 increases with the order of solid line, dotted line (short dotted line) and dotted line (long dotted line) to the bottom from the top of Fig. 5 A.At first, under with the little situation of the amount of pushing of the developer roll shown in the solid line, contact pressure becomes maximal value in contact clamping part central portion office.Then, under the amount of pushing of developer roll 3 increases with the situation that is converted to deformation state shown in broken lines; " lax " partly be formed on the contact clamping part middle body, the peaked position of contact pressure moves to the upstream and downstream of developer roll from the direction c of clamping part middle body rotation.In addition, increase to be converted to the deformation state shown in the dotted line in the amount of pushing of developer roll, the peaked position of contact pressure further moves to upstream side and the downstream of the direction c of developer roll rotation.

Fig. 5 B shows the lap between developer roll 3 and flexible sheet material member 40, solid line, dotted line (short dotted line) and dotted line (long dotted line) with from the order of the end of Fig. 5 B corresponding among Fig. 5 A those.In case be appreciated that having overlapping arc has constant curvature, its lap becomes maximum in the central authorities of contact portion, and along with the lap position moves to upstream side and downstream, it is very little that its lap becomes gradually.Yet in this structure, " flaccid part " is formed on the contact clamping part middle body that contact pressure becomes maximum at first, and contact pressure reduces then.In addition, described as Fig. 5 A, the position that the contact pressure except original position becomes maximum moves to upstream side and the downstream that lap diminishes.Therefore, under the dotted line in Fig. 5 A and the situation of dotted line, the variation of the lap of being represented by the length of arrow shown in Fig. 5 B is very little.Therefore, the maximal value of contact pressure does not change pro rata with the increase of the amount of pushing of developer roll, thereby almost can keep particular value.As mentioned above, as described in Figure 4, have such zone, wherein the maximal value of contact pressure does not have to change pro rata with the amount of pushing of developer roll 3.Therefore, in this example, the ideal maximum value of contact pressure can be set with stationary mode, thereby there is no need to obtain high precision when assembling.

In addition, when reducing the size of developer roll 3, it is big that the curvature of developer roll becomes, and therefore, the maximal value of contact pressure does not become more remarkable with the trend that the increase of the amount of pushing of developer roll 3 changes pro rata.Therefore, this trend is reducing advantageous particularly on the size of developer roll.

B) unevenness of vertical image color after durability test

Then, with describe this aspect durability test after in the advantage aspect vertical image color unevenness.For the developer level adjustment means according to comparative example 3,7 and 8, vertical image color unevenness of solid picture appears after durability test.At this moment because after durability test, occur the variation of toner deterioration situation in the vertical.As mentioned above, for the developer level adjustment means with traditional structure, the maximal value of contact pressure increases along with the amount of pushing of developer roll is linear.

In case the maximal value of the contact pressure between developer roll 3 and developer level adjustment means increases, by the developer level adjustment means adjusting power that toner produces is reinforced, thereby it prevents that effectively toner is under the situation that not have adjusting and excessively pass through.Yet as by the result of developer level adjustment means to the increase of the stress of toner, toner is easily by adjustment means crushing of toning dosage and fusing.The deterioration of having accelerated toner thus is to shorten its life-span significantly.

For having traditional structure ground developer level adjustment means, the circumferential deformation of the variation of production, developer roll 3 etc. causes the amount of pushing of 3 pairs of developer level adjustment means of developer roll to occur in the vertical changing.Therefore, it is contemplated that out that the maximal value of the contact pressure between developer roll 3 and toning dosage adjustment means changes in the vertical.Thereby during durability test, the toner deterioration situation changes in the vertical, thus, after durability test, produces vertical image color unevenness on solid picture.

For the developer level adjustment means according to this example 1,3 and 4, there is such zone in another aspect, and wherein the maximal value of the contact pressure between developer level adjustment means and developer roll 3 is along with the amount of pushing of developer roll 3 increases.Therefore, be confined in this local, can absorb the variation of the amount of pushing of 3 pairs of developer level adjustment means of developer roll in the vertical as long as use.Therefore, even after permanance, can prevent vertical image color unevenness of solid picture.

C) the image color unevenness that produces owing to the vestige that pressurizes

Then, with describe the present invention about in the variation of local shape for example according to the comparative result between example 1 and comparative example 3 aspect the recess of the developer roll 3 of first embodiment.

Grade in case have the identical portions that the developer roll 3 of flexible layer pressed the developer level adjustment means for a long time, recess on pressing part, occurs as permanent compression set.In case when traditional developer adjustment means is applied on the developer roll 3 that recess occurs, comprising that the variation as the amount of the toner coating of the developer level on developer roll 3 for example appears in the part of the variation of recess in local shape.On the other hand, in the contact developing method, develop with high development efficient, thereby the unevenness of the amount of the toner coating on developer roll 3 is reflected on the image faithfully.

On the other hand, in example 1, the image color unevenness of the recess of developer roll 3 is suppressed because local shape ground for example changes.As mentioned above, in example 1, the contact clamping part between developer roll 3 and flexible sheet material member 40 comprises: at the contact area A1 of clamping part upstream portion; Zone A2, the flaccid part 7 that wherein has low contact pressure in the clamping part centre; Contact area A3 in clamping part downstream central authorities.As the action of this structure, flexible sheet material member 40 can be in response to the variation of the local shape for example recess of developer roll 3 and local deformation.That is to say that flexible sheet material member 40 can be followed the recess of developer roll 3.

With reference to Fig. 6 its mechanism is described below.Fig. 6 A simulation also illustrates according to the flexible sheet material member 40 of this example and the contact condition of developer roll 3.When developer roll 3 was pushed flexible sheet material member 40 1 scheduled volumes, L1 represented the circumferential surface of developer roll 3 linearly.In addition, L2 is illustrated in state (state that the pressure between flexible sheet material member 40 and developer roll 3 is substantially zero) that developer roll 3 the is not pushed into position of the arc apex of flexible sheet material member 40 down.The amount of pushing of the 3 pairs of flexible sheet material members 40 of distance expression developer roll between L1 and L2.Then, the L3 in Fig. 6 B and 6C is illustrated in for example circumferential surface of the developer roll located of the recess etc. of developer roll 3 of part that local shape changes linearly, and the recessed amount (space) of the distance expression developer roll 3 between L1 and L3.

At first, Fig. 6 C illustrates when the contact condition of the variation that comprises local shape when for example the part of the recess etc. of developer roll 3 enters the contact clamping part.The clamping part upstream portion A1 basis of flexible sheet material member 40 is out of shape in the variation of the shape of the developer roll 3 shown in Fig. 6 C.At this moment, have " flaccid part " 7 of clamping part middle body A2, clamping part upstream portion A1 can be out of shape according to the variation of shape thus, and does not exert an influence on the A3 of clamping part downstream part.

Then, Fig. 6 B shows the contact condition when the part that comprises change of shape is come out from clamping part.The clamping part downstream part A3 of flexible sheet material member 40 is out of shape according to the variation of shape.At this moment, as identical when entering clamping part, have " flaccid part " 7 of clamping part middle body A2, clamping part downstream part A3 can be out of shape according to the variation of shape thus, and exerts an influence on clamping part upstream portion A1.

In other words, the existence of " flaccid part " 7 of sheet material middle body makes the clamping part upstream portion A1 of flexible sheet material member 40 and clamping part downstream part A3 distortion, so that the variation of the following local shape recess of developer roll 3 for example.Therefore, contact pressure can be limited significantly with the fluctuation that the toner that contacts the clamping part inlet receives width.Therefore, the variation of the amount of the amount of the toner coating on developer roll 3 and generation image error can be suppressed.Therefore, can suppress significantly owing in the variation of the local shape image color unevenness in the developer roll circulation that causes of the recess of developer roll 3 for example.

On the other hand, for developer level adjustment means according to comparative example 3 since the variation of local shape for example the density unevenness that produces of the recess of developer roll 3 spare in solid picture and two class images and all occur as the half tone image of image error.In comparative example 3, a sheet metal quilt side bearing along the longitudinal is to contact with developer roll 3.For such structure, the part of the variation that comprises local shape along with developer roll 3 rotate into the contact clamping part, be included in rigidity in the sheet metal prevent local shape along with the variation of shape for example developer roll 3 recess and change.Therefore, for the variation that the comprises local shape part of the recess of developer roll 3 for example, contact pressure and the toner that contacts the clamping part inlet receive the fluctuation of width, and this makes and form the inhomogeneous of toner coating on developer roll 3.Thus, image error is as the inhomogeneous appearance of developer roll round-robin image color.

D) ghost image

Then, about the advantage of the present invention at ghost image, with the comparative result that is described between example 4 and the comparative example 8, this ghost image occurs corresponding to the circulation of conduct according to the development sleeve of the developer bearing member of the 3rd embodiment.

In comparative example 8, in the development sleeve circulation ghost image appears.This is to be produced by the inhomogeneous of the amount of the charging toner on the amount of toner coating and the development sleeve 3a.Now, consume toner corresponding to the part of the development sleeve 3a of the image section of Electrifier frame, photoreceptor, thereby the amount of the toner on development sleeve 3a reduces.On the other hand, be not consumed corresponding to the toner of the part of the development sleeve 3a of the non-image part of Electrifier frame, photoreceptor, thereby the amount of the toner on the development sleeve 3a remains unchanged.Incidentally, do not comprise the donor rollers that constitutes the developer replenishing developer roll according to the developing apparatus of the 3rd embodiment, the supply of developer is carried out with magnetic means.Under the situation that donor rollers is not set, the toner supply developer roll is not carried out mechanically, thereby according to whether there being toner to consume the amount difference that makes the toner of before developer level adjustment means 4 and then, supplying with at an easy rate in the development section office.Therefore, in the development sleeve circulation ghost image appears easily.

In comparative examples 8, the contact pressure that can visualize the developer adjustment means changes according to the amount of the toner of supplying with easily, the ghost image relevant with video recording occur.On the other hand, example 4 has limited the ghost image in the development sleeve circulation significantly.This is because the difference of the amount of the toner that occurs on development sleeve after developing.Developer level adjustment means 4 according to example 4 can not only make even the rising of contact pressure make the amount of toner coating even.

In addition, toner is supplied with magnetic means, thereby uncharged toner is supplied at certain part place, is consumed in the development section office at this part toner, before developer level adjustment means 4 and then.Therefore, in order to suppress ghost image, must a side of developer level adjustment means 4 by during provide suitable electric charge to toner.In this example, on the surge pressure in downstream and surge pressure, carry out twice charging, thereby the new uncharged toner of supplying with can be through charging fully at upstream side.

As mentioned above, in this example, can be suppressed at the development sleeve ghost image of cycle period significantly.

Advantage with respect to comparison techniques

Then, will the difference of first embodiment and comparison techniques be described.Particularly, with comparative example 1 and comparative examples 1,2 and 4-6.

A) precision when reducing size and cost

At first, the influence of advantage of the present invention when realizing reducing size will be illustrated in.Paper sheet thickness in the comparative examples 1 is thicker than the paper sheet thickness in example 1, thereby elastic force is higher.Therefore, even under the situation that the amount of pushing of developer roll 3 increases, contacted by surface with the developer roll 3 under the flexible sheet material member 40 of U-shaped supporting and the state that sweep at its curved surface almost is not recharged.In comparative example 1, in case the amount of pushing of developer roll increases, the maximal value of contact pressure is also linear to be increased.Therefore, when reducing size, must assemble with very high precision.

Then, in the comparative example 2 shown in Figure 14, when supporting U-shaped flexible sheet material member 40, the side of two ends transversely of flexible sheet material member 40 is not conditioned.Therefore, in comparative example 1, in case the amount of pushing of developer roll increases, the maximal value of contact pressure is also linear to be increased, thereby is difficult to stable manner the maximal value of contact pressure is set to predetermined value.

In addition, in comparative example 2, as mentioned above, the side of two ends transversely of flexible sheet material member is not conditioned.

Therefore, the power that produces by receiving because in the friction force of contact portion and developer roll 3 and subsiding easily in the downstream of the sense of rotation c of developer roll 3 along circumferencial direction.Thus, occur such problem easily, that is, fluctuate the contact position shakiness easily as the state of the flexible sheet material member 40 of developer level adjustment means.

In addition, for having and the circumferential surface of the developer roll 3 developer level adjustment means that contacts recess of same flexure substantially of for example comparative example 4,, must guarantee surface accuracy in order to contact with the circumferential surface of developer roll 3 in the vertical with stationary mode.Therefore, require processing with very high degree of precision.

Comparative example 5 has the structure that comprises first cockscomb 17 and second cockscomb 21 along the rotation direction c of developer roll 3.The reason that the cockscomb of each unit can not reduce dimensionally is identical with reason in comparative example 3.In addition, have along a plurality of cockscombs of the sense of rotation of developer roll 3, it further makes and is difficult to reduce size.

In addition, in comparative example 6, comprise that the scraper plate 23 of the recess 24 with bending radius littler than the radius of developer roll 3 contacts with developer roll 3, thereby two edges contact the interior side contacts of clamping part with one.

The sharp edges of inflexibility cockscomb part contacts with developer roll 3, thereby with respect to the variation of the amount of pushing of developer roll 3, the maximal value of contact pressure excessively increases.The reducing of size demonstrates this influence significantly.

In addition, for the contact condition of the marginal portion of sheet metal, the clamping part width narrows down widely, and this is ad infinitum near line contact.For two edges are contacted with having crooked developer roll 3 in the vertical, require assembling with very high degree of precision.

On the other hand, for the developer level adjustment means 4 according to example 1, as shown in Figure 4, have such zone, that is, the maximal value of contact pressure does not change pro rata with the increase of the amount of pushing of developer roll 3.Therefore, the ideal maximum value of contact pressure can be set with stable manner, thereby need not obtain high precision when assembling.In addition, in example 1, as by pushing the result that developer roll 3 is contacted with developer level adjustment means 4, for the contact area in the middle of developer level adjustment means 4 and developer roll 3, form such state, that is, wherein developer level adjustment means 4 with contact at the upstream side of developer roll 3 and two positions in downstream.Therefore, even for simple assembling, can realize contact condition with stable manner all the time.As mentioned above, for developer level adjustment means 4,, there is no need to provide the high precision assembling even when reducing size according to example 1.

In addition, with example 1 irrespectively, with whole other example class seemingly, the surface in contact of developer level adjustment means and developer bearing member can be the smooth surface that does not have step and edge.This is because similar with comparative example 6, in case step or edge contact with developer roll, as mentioned above, stress raisers occur.Under these circumstances, require assembly precision, be difficult to assembling like this.In addition, similar with comparative examples 6, provide step or edge to be difficult to molded developer level adjustment means.

B) vertically image color is inhomogeneous after durability test

Then, the advantage of durability test the present invention afterwards on vertically density unevenness is spared will be described in.For the developer level adjustment means according to comparative example 1,2,4-6, the vertical image color that occurs solid picture after durability test is inhomogeneous.As mentioned above, for the developer level adjustment means with traditional structure, the maximal value of contact pressure increases linearly with respect to the amount of pushing of developer roll 3.

For developer level adjustment means with traditional structure, because push amount in the vertical the variation of developer roll 3 with respect to the developer level adjustment means appears in the variation aborning and the circumferential deformation of developer roll 3 etc., appears at the peaked variation of the contact pressure between developer level adjustment means and the developer roll 3 in the vertical.Therefore, appear at the variation of toner deterioration situation in the vertical during durability test, thus, the vertical image color that occurs solid picture after durability test is inhomogeneous.

On the other hand, for developer level adjustment means 4 according to the present invention, have such zone, wherein the maximal value of the contact pressure between developer roll adjustment means 4 and developer roll 3 does not increase with respect to the amount of pushing of developer roll 3.Therefore, be confined to this zone, can be absorbed with respect to developer level adjustment means 4 amount of pushing in the vertical at developer roll 3 as long as use.Therefore, can prevent that after durability test vertical image color of solid picture is inhomogeneous.

C) because the image color of the vestige of pressurization is inhomogeneous

Then, the present invention is described because the density unevenness of the recess of developer roll 3 advantage on even for example of the variation in local shape.

At first, for developer level adjustment means according to comparative examples 1 since local shape for example the recess of developer roll 3 appear on solid picture and the two class images in that the density unevenness on the developer roll is even as the half tone image of image error.In comparative example 1, even under the situation that the amount of pushing of developer roll 3 increases, developer level adjustment means and the bending of its curved surface do not have the surface of the developer roll 3 under the state of variation to contact.At this moment, the pressure distribution of the contact clamping part that forms between developer roll 3 and flexible sheet material member 40 comprises a maximal value.Therefore, in contact clamping part middle body, there be not " flaccid part ".Therefore, the variation that is difficult to follow fully local shape for adjustment means is the recess of developer roll 3 for example, thereby occurs inhomogeneous on the amount of the toner coating of developer roll 3.Thus, image error occurs as the concentration error in the developer roll circulation.

On the other hand, for developer level adjustment means according to this example 1, in central clamping part middle body, " flaccid part " 7 arranged, the clamping part upstream portion A1 of flexible sheet material member 40 and clamping part downstream part A3 can be out of shape thus, so that the variation of the following local shape recess of developer roll 3 for example.Therefore, contact pressure is suppressed significantly with the fluctuation that the toner that contacts the clamping part inlet enters width.Thus, the variation with the amount of the as many toner coating on developer roll 3 of amount that forms image error can be limited.Thus, because the variation of local shape image color inhomogeneous can be significantly suppressed of recess in the developer roll circulation of developer roll 3 for example.

Then, for developer level adjustment means according to comparative example 2, because the variation of local shape image color inhomogeneous appear at solid picture on of recess in the developer roll circulation of developer roll 3 for example, but do not appear on the half tone image.In comparative example 2, even under the situation that the amount of pushing of developer roll 3 increases, prevent that the fold of flexible sheet material member from occurring, and on contact clamping part middle body, do not have " flaccid part ".For with the contact portion of developer roll 3 in pressure portion, form a maximal value, it makes in the contact pressure maximum of contact clamping part.Therefore, the variation that is difficult to follow local shape fully at upstream side and place, downstream as the clamping part of example 1 for flexible sheet material member 40 is the recess of developer roll 3 for example, thereby occurs inhomogeneous on the amount of the toner coating of developer roll 3.Thus, in the developer roll circulation, on solid picture, occur as the even image error of density unevenness.Yet the density unevenness that does not appear in half tone image in the developer roll circulation is even.In comparative example 2, used flexible member, the deflection of original state is very big, attempts to return to the operation of original state and carries out with respect to pushing of developer roll 3.Half tone image has the low development efficient of comparing with solid picture, thereby under the very little situation of the variation of the amount of toner coating, the varied concentration of amount that prevents reflection developer coating is inhomogeneous.In comparative example 2, can visualize the variation of the amount that prevents the amount as many developer coating even thus with in half tone image, causing density unevenness.

Then, for developer adjustment means, because for example the density unevenness in the developer roll circulation that causes of the recess of developer roll 3 is even appears on solid picture and the two class images as the half tone image of image error in the variation of local shape according to comparative examples 4.Comparative examples 4 is such example, that is, developer roll 3 contacts through the surface with the developer level adjustment means, realizes wide contact clamping part width thus, is adjusted in the toner on the developer roll 3.Yet, the character of applied material is not flexible member but rigid member, wherein with the surface in contact shape of developer roll 3 substantially by with identical being bent to form of circumferential surface of developer roll 3, therefore, be difficult to according to for example recess distortion of developer roll 3 of variation for such member at local shape.Therefore, for the variation that comprises local shape for example the recess of developer roll 3 part, contact pressure and contact the fluctuation that the toner of clamping part inlet enters width, fluctuation appears on the amount of the toner coating on the developer roll 3.Therefore, in the developer roll circulation, occur as the uneven image error of image color.

In addition, for developer level adjustment means according to comparative example 5 since the variation of local shape for example the density unevenness on developer roll that causes of the recess of developer roll 3 is even appears in solid picture and the two class images as the half tone image of image error.Comparative example 5 has and comprises along first cockscomb 17 of the sense of rotation c of developer roll 3 and the structure of second cockscomb 21.Yet for first cockscomb 17 and second cockscomb 21, the advantage that is applied to the toner on the developer roll 3 by each cockscomb and method are identical with in the comparative example 3 those.Therefore, according to comparative example 3 more described reasons, occur since the variation of local shape for example the image color on developer roll that causes of the recess of developer roll 3 is inhomogeneous.

Then, for developer level adjustment means according to comparative example 6 since the variation of local shape for example the image color on the developer roll that causes of the recess of developer roll 3 is inhomogeneous appears on solid picture and the two class images as the half tone image of image error.In comparative example 6, comprise that the scraper plate of the recessed portion with bending radius littler than the radius of developer roll 3 contacts with developer roll 3, thereby two edges contact the interior side contacts of clamping part with one.For such structure, present two peak Distribution in the pressure distribution that contacts clamping part, it comprises two maximal values.Yet the character of materials used is metal, thereby, be difficult to follow variation partly in the shape of developer roll 3 at each contact point, thus, occur since the variation of local shape for example the image color on developer roll that causes of the recess of developer roll 3 is inhomogeneous.

In addition, because the edge of link plate contacts with developer roll 3, the maximal value of contact pressure exceedingly increases.Therefore, occurring the recessed of developer roll 3 easily in long-standing neglect, is disadvantageous for restriction owing to the recessed image color of developer roll 3 is inhomogeneous like this.

Recently, example 2 is described.For the developer adjustment means 4 according to example 2 identical with example 1, contact clamping part between developer roll 3 and flexible pipe member 41 is included in the contact area A1 of clamping part upstream portion, contact pressure in the regional A2 of clamping part central authorities is less, and " flaccid part " 7 occur, contact area A3 is in the clamping part downstream part.Therefore, there is such zone, that is, do not change pro rata with the amount of pushing of developer roll 3 with the maximal value of the contact pressure of developer roll 3.Therefore, when reducing size, the ideal maximum value of contact pressure can be set with stable manner, and does not have high-precision assembling.

In addition, be confined in such zone as long as use, that is, the maximal value of the contact pressure between developer roll adjustment means 4 and developer roll 3 does not increase with respect to the amount of pushing of developer roll 3, and the amount of pushing of developer roll 3 can be absorbed with respect to developer level adjustment means 4 variation in the vertical.Therefore, can prevent that after durability test vertical image color of solid picture is inhomogeneous.

In addition, in contact clamping part middle body, " flaccid part " 7 arranged, thereby the clamping part upstream portion A1 of flexible pipe member 41 and the A3 deformable of clamping part downstream part are so that the variation of following local shape developer roll 3 recessed for example.Therefore, contact pressure can obviously be suppressed with the fluctuation that the toner that contacts the clamping part inlet enters width.Thereby, can be suppressed with the variation of the amount of the as many toner coating on developer roll of amount that forms image error.Thus, because the variation of local shape developer roll 3 recessed and can obviously being suppressed in that the image color of developer roll on the cycle is inhomogeneous for example.

Yet this member is a pipe component, that is, annular shape, thus when peak along with the variation of shape during at upstream and downstream, motion propagates into rear side.Thereby inhomogeneous in nonspecific circulation appears on the amount of toner coating of developer roll 3, and it is inhomogeneous to occur spacing thus in image.

For above-mentioned example, the developer level adjustment means is not limited to two to the peaked quantity of the pressure distribution of developer bearing member, but can be three or more.

To operation and the advantage about above-mentioned example be described below.Developer level adjustment means 4 according to this example can be improved the included problem of traditional developer level adjustment means (cost when reducing size and drawback, the vertical image color after durability test is inhomogeneous) in the mode of abundant balance.

Even when reducing size, according to the not high-precision assembling of needs of developer level adjustment means 4 of this example owing to following reason.Have such zone, wherein the maximal value of contact pressure does not change pro rata with the increase of the amount of pushing of developer roll 3.Thereby the ideal maximum value of contact pressure can be by with the stationary mode setting, thereby there is no need to obtain when assembling high precision.In addition, for the present invention, be pushed into the result who contacts with developer roll amount adjustment means 4 as developer roll 3, contact portion between developer roll amount adjustment means 4 and developer roll 3 is formed on such state, that is, two points in upstream side and downstream contact with developer roll 3 on sense of rotation c.Therefore, even for simple assembling, can stably realize stablizing contact condition.

In addition, the vertical image color after validity test is inhomogeneous can be owing to following reason is suppressed effectively.For developer adjustment means 4 according to this example, there is such zone, wherein the maximal value of the contact pressure between developer level adjustment means 4 and the developer roll 3 does not increase with respect to the amount of pushing of developer roll 3.Therefore, be confined to such regional extent as long as use, the amount of pushing of developer roll 3 can be absorbed with respect to developer level adjustment means 4 variation in the vertical, and after durability test even can suppress that image color is inhomogeneous longitudinally.

Carry out the size that this example can reduce developing apparatus, can improve assembly performance, and compare with conventional art and to have the simple structure that will realize.In addition, develop with toner layer with stable manner for a long time.

Then, the details of another example of another example of imaging device and developing apparatus will be described with further reference to accompanying drawing.Following examples of developing apparatus as the 3rd embodiment of developing apparatus, are the noncontact developing method, and it is another example of being arranged to the method for developing by the magnetic single component developer.

[another example of imaging device]

Description is comprised one-piece construction and operation according to another example of the imaging device of developing apparatus of the present invention.Fig. 1 shows the schematic cross sectional views according to the imaging device 100 of this example.Imaging device 100 is for adopting the laser printer of transfer printing electrophotographic method.

Imaging device 100 comprises that this Electrifier frame, photoreceptor is the rotation drum type with 24mm diameter as the OPC Electrifier frame, photoreceptor of image bearing member (developing member) (hereinafter referred to as " photosensitive drums "), and has negative pole for this example.Photosensitive drums 101 is driven rotation along the clockwise direction among the figure with constant circumferential speed speed (surperficial translational speed) 85mm/sec.For the imaging device 100 according to this example, the peripheral speed of photosensitive drums 101 equals processing speed (print speed).

(print speed)

Charging roller 102 as the charhing unit of photosensitive drums 101 is set on the circumference of photosensitive drums 101.Charging roller 102 can be the flexible roller of electric conductivity, and comprises core body 102a and the electric conductivity flexible layer 102b that is formed on the core body 102a.Charging roller 102 is pressed against on the photosensitive drums 102 by a pair of predetermined pressure.Thus, charhing unit (charging clamping part) c1 is formed between charging roller 102 and the photosensitive drums 101.In this example, charging roller 102 is by the rotation driven in rotation of photosensitive drums 101.

Charging roller 102 links to each other with charging grid bias power supply S1, and charging grid bias power supply S1 is as the charging bias voltage feed unit that is configured to apply the charging bias voltage, and in this example, the dc voltage that is at least disruptive potential is applied between charging roller 102 and the photosensitive drums 101.Particularly, as the charging bias voltage, bias voltage, its bias voltage have the AC voltage of VPP of 1.4kv and the frequency that is applied 1.3kHz, have been applied in-dc voltage of 600V, and the surface of photosensitive drums 101 evenly is filled with-600VDE charging voltage (dark space voltage) through contact

In addition, the laser beam scanner (exposure device) 103 that comprises laser diode and polygon prism etc. is arranged on the circumference of photosensitive drums 101.Laser beam scanner 103 output adds the laser beam L of modulation according to the time series digital pixel of target image information, and with the uniform charging surface of the laser beam L scanning and the rotating photosensitive drum 101 that exposes.Undertaken by laser beam L under the situation of whole face exposure in the uniform charging treatment surface of photosensitive drums 101, laser power is conditioned and makes the current potential on surface of photosensitive drums 101 become-150V.According to scan exposure, be formed on the surface of photosensitive drums 101 corresponding to the electrostatic image (sub-image) of target image information with laser beam L.

In addition, be configured to make developing apparatus 104A to be set on the circumference of photosensitive drums 101 at the electrostatic image development that forms on the photosensitive drums 101.Developing apparatus 104A in Figure 19 has adopted the developer level regulating device of describing after a while 143 according to example 5.Although will be described later its details, developing apparatus 104A storage magnetic single component developer, that is, and toner (magnetic color tuner) t, its in as the developer reservoir 145 of developer storage unit as developer.Toner t is charged by triboelectric charge.Thus, the development sleeve 141 and the development bias voltage between the photosensitive drums 101 that are applied to as developer bearing member (developing member) develop electrostatic latent image on the developing regional a1 on the photosensitive drums 101, face with each other at developing regional a1 place development sleeve 141 and photosensitive drums 101.The development bias voltage is applied by developing bias supply S2, and developing bias supply S2 is as the development bias voltage feed unit that links to each other with development sleeve 141.

In addition, its resistance is medium and is set on the circumference of photosensitive drums 101 as the transfer roll 106 of transfer printing unit.Photosensitive drums 106 is being pressed photosensitive drums 101 with predetermined contact pressure, and forms transfer section (transfer nip) b1.Transfer materials P as recording member is scheduled to periodically supply with transfer nip b1 from paper-supply section.In addition, predetermined transfer bias is applied power supply S3 from the transfer bias as the transfer bias applying unit and is applied to transfer roll 106.Thus, the toner image on the photosensitive drums 101 by primary transfer to the surface of the transfer materials P that is fed into transfer nip b1.

The transfer roll 106 that this example is used is for having the transfer roll of roller resistance value 5 * 108 Ω.Transfer roll 106 comprises core body 106a and the medium resistance froth bed 106b that is formed on the core body 106a.Subsequently, by apply+transfer bias of 2.0kV carries out transfer printing to core body 106a.The transfer materials P that imports transfer nip b1 is transmitted from transfer nip b1 in the mode that clips by photosensitive drums 101 and transfer roll 106.Subsequently, the lip-deep toner image that forms and be carried on photosensitive drums 101 is by electrostatic force with restrain the face side that intensity is transferred to transfer materials P successively.

The transfer materials P that supplies with transfer nip b1 is at developer roll 101 side transfer printing toner images, and in the surface isolation of photosensitive drums 101, is imported into the fixing device 107 that adopts the heat fusing method in this example then.In case with the toner image on it, transfer materials P is used as imaging article (printout) and is discharged to the device outside.

In addition, cleaning device 108 is disposed on the circumference of photosensitive drums 101, and cleaning device 108 is as the cleaning unit on the surface that is configured to clean photosensitive drums 101.Cleaning unit 108 is wiped the toner of staying on the photosensitive drums 101 (the remaining toner of transfer printing) off at cleaning balde 108a place, and it is stored among the waste-toner container 108b.The photosensitive drums 101 that is cleaned thus is recharged roller 102 chargings, and is recycled and reused for imaging.

In this example, photosensitive drums 101, charging roller 102, developer roll 104A and cleaning device 108 are integrally formed box, therefore produce with respect to the dismountable handle box 109A of imaging device master component.Handle box is such box, that is, developing apparatus and cleaning unit that at least one Electrifier frame, photoreceptor, conduct are configured to act on the processing unit on the Electrifier frame, photoreceptor are integrally formed, and detachable with respect to the imaging device main unit.The handle box corresponding with this example comprises at least one Electrifier frame, photoreceptor and developing apparatus.Yet, according to this example be not limited to handle box with respect to the dismountable box of imaging device main unit, but can adopt any box, as long as developing apparatus is at least with respect to the imaging device main unit detachably.For example, can use developing apparatus with respect to the dismountable box of imaging device (Delevoping cartridge).

[the 4th embodiment of developing apparatus]

Then, with the developing apparatus of describing in further detail according to present embodiment.In the present embodiment, metal sleeve of coated with conductive resin is used as the development sleeve 141 of developer bearing member on it.Development sleeve 141 is driven rotatably by the counter clockwise direction of the arrow in figure.That is to say, in the present embodiment, photosensitive drums 101 and development sleeve 141 made along direction rotation two surfaces in the face of the part place along forwards to moving mutually.Having fixedly magnetic roller 142 that predetermined polarity arranges is set in the development sleeve 141 as near the magnetic fields that are configured to toner t at least is drawn onto the development sleeve 141 and forms member.Particularly, magnetic roller 142 is for being configured to form the fixed magnet of magnetic force on each part of development sleeve 141.In this example, as shown in figure 20, magnetic roller 142 is included in development utmost point Sa, carry electrode Na, supply with the peak density on each part of utmost point Sb and collector Nb.Be noted that N and S represent the magnets N utmost point and the S utmost point respectively.

Measurement according to the magnetic flux density of this instructions is undertaken by gaussmeter series 9900 and the detector A-99-153 that Bell Inc. makes.Gaussmeter comprises the rod axis probe that links to each other with the gaussmeter main unit.Development sleeve is flatly fixed, and the magnetic roller of portion is connected so that rotate within it.Probe with height attitude by the layout that is tilted to the right with respect to development sleeve with becoming a determining deviation.In addition, probe is fixed and makes the center arrangement of the center of development sleeve and probe on approximately identical surface level, and measures under such state.The magnetic roller can be concentric with development sleeve haply cylindrical member.The spacing that can envision between development sleeve and magnetic roller equates in that any part is consistent.Therefore, the surface location of development sleeve and the magnetic flux density on the normal direction at surface location place are measured, rotate the magnetic roller simultaneously, thereby can use on the circumferencial direction of development sleeve the measurement result in all positions.The peak velocity of each position obtains from magnetic flux density data in a circumferential direction, and is taken as Br.Subsequently, the size of Br is by polar coordinate representation.

Think that the initial point of angle θ is the peak value of the magnetic flux density on the normal direction of supplying with utmost point Sb.In this example, especially, the peak of magnetic flux density on the normal direction of development utmost point Sa is positioned in developing regional a1, and photosensitive drums 1 and development sleeve 141 face with each other there.In addition, as shown in figure 20, the peak of the magnetic flux density on the normal direction of adjacent pole departs from 90 degree substantially along the circumferencial direction of development sleeve 141.Be noted that we think angle θ forward for along the apparent motion direction (sense of rotation) of developer roll 141 at the downstream direction of initial point (that is Sb → Na → Sa → Nb → Sb).

As toner (magnetic color tuner) t of magnetic single component developer by binder resin, magnetisable material particle and charge control agent are mixed, by each technology mixing, in grinding, classifying, and fluidizing agent etc. added as external additive.For the magnetisable material particle, can be by the magnetic-particle of enough magnetic force transmission by the regulation identical weight as the binder resin manufacturing.In addition, the average grain of toner (D4) is 8 μ m.

Be sent to during the processing of passing through magnetic roller 142 reception magnetic force on the development sleeve 141 simultaneously at toner t, toner t stands layer thickness to be regulated (developer level adjusting) and applies electric charge at developer level regulating device 143 places.In addition, developing apparatus 104A is included in the agitation means 144 in the developer reservoir 145, agitation means 144 is formed at circulation toner t in the developer reservoir 145, and subsequently toner t is transported to magnetic force wherein and can reaches in the scope of circumference of development sleeve 141.The details of regulating device 143 is described with reference to the example of describing later and comparative example.

The toner t that is coated on the development sleeve 141 is sent on the part (development part) of developing, and photosensitive drums 101 and development sleeve 141 face with each other by the rotation of development sleeve 141 there.Here, to be arranged in the position of the most close photosensitive drums 101 interval be 300 μ m to development sleeve 141.In addition, development bias voltage (dc voltage value :-450V, AC magnitude of voltage: Vpp1.8kV, 1.6kHz, rectangular wave) applies voltage S2 by the development bias voltage and is applied to development sleeve 141.

Development sleeve 141 is driven by the peripheral speed with 1.2 times developer roll 101.Thereby, at the electrostatic image of developer roll 101 sides by toner t discharged-area development.Patent, development sleeve 141 is set to 1.2 times with respect to the peripheral speed of photosensitive drums 101, but development sleeve 141 is not limited thereto with respect to the peripheral speed of photosensitive drums 101.The peripheral speed that it is desirable to set development sleeve 141 equals the peripheral speed of 1.0-2.0 photosensitive drums 101 doubly, can obtain advantage of the present invention fully.

In addition, for the magnetic roller 142 in development sleeve 141, magnetic pole be set at development part a1 around, in this example, be set to 800G at the lip-deep magnetic force of development sleeve 141.Thereby the toner t that can prevent to have improper electric charge unexpectedly flies to charging voltage (the non-image part voltage) part of photosensitive drums 101, and this improper electric charge can not be controlled as voltage setting value.

Now, as mentioned above, use usually as being included under the situation of scraping tabular adjustment means of the adjustment means in the developer level regulating device in a side along the longitudinal, ghost image and density unevenness even (vertically density unevenness is even) adjustment means vertically on occur easily.

One of this 4th embodiment is characterised in that and can restrains because the image error that the problem of adjustment means causes, for example ghost image, vertically density unevenness is even etc.In addition, the adjustment means that constitutes according to this 4th embodiment can be adjusted in the developer on the developer bearing member, and can realize reducing of size simply, and can form toner coating with stable manner, this with a side along the longitudinal that is used for traditionally being coated with to scrape that tabular adjustment means compares be favourable.

In the present embodiment, carry out such layout, promptly, for the developing apparatus that adopts magnetic single component noncontact developing method, regulating device comprises the soft readjustment member, and this adjustment means forms contact portion (clamping part), and adjustment means contacts with developer bearing member there.Subsequently, carry out such layout, that is, and in the maximal value that a plurality of contact pressures are arranged in contact pressure distributes on the surperficial moving direction of developer bearing member.In addition, carry out such layout, that is, form the magnetic flux distribution that member produces magnetic field by magnetic field, the peak of the magnetic flux density of close clamping part is outside clamping part.

Below with reference to the example of developer level regulating device as used herein and comparative example developing apparatus according to the 4th embodiment will be described.

[example 5-9 and comparative example 9-13]

Example 5

Adjustment means: the U-shaped sheet element, contact pressure: two peak values, hithermost magnetic pole:

The downstream of clamping part

Figure 21 illustrates the schematic cross sectional views according to the regulating device 143 of this example.Figure 21 A illustrates the adjustment means 143a that supports and be included in the regulating device with U-shaped and contacts state before with developer roll 141.In addition, Figure 21 B is illustrated in developing member 143a with predetermined amount of pushing and developer roll 142 state of contact.

Shown in Figure 21 A, comprise as the flexible sheet material member 143a of adjustment means with as the sheet material retaining member 143b of the retaining part that is configured to keep adjustment means according to the regulating device 143 of this example.Retaining member 143b can be connected to the frame unit of developing apparatus, perhaps can be used as the part of developing frame unit, and the frame unit of this developing frame unit and developing apparatus is integral model.

Here, flexible sheet material member 143a forms by bending in the vertical, so that with respect to transverse curvature.In this example, flexible sheet material member 143a is by along the apparent motion direction bending of development sleeve 141, vertically substantially parallel perpendicular to the direction of bending direction and development sleeve 141.In other words, regulating device 143 be set to whole vertically and development sleeve 141 vertically substantially parallel.

Shown in Figure 21 B, flexible sheet material member 143a along the U-shaped bending comprises first contact portion A1 and the A2, the first contact portion A1 contacts with developer roll 141 along horizontal direction on the outside of cardinal principle middle body 143a1 with A2, and middle body 143a1 has the outstanding shape in the face of development sleeve 141.The outside of the cardinal principle middle body 143a1 of flexible sheet material member 143a is outstanding from recessed portion 143b1, and recessed portion 143b1 is formed on the side in the face of development sleeve 141 of flexible sheet material retaining member 143b.Subsequently, in inside that two end 143a2 transversely and the 143a2 of flexible sheet material member 143a are connected to the recessed portion 143b1 of flexible sheet material member 143b.

At this moment, attempt to act on the flexible sheet material member 143a from the elastic force F-1 of longitudinally crooked recovering state.Therefore, by pressure along the apparent motion direction of development sleeve 141 second contact position B1 and the B2 at upstream and downstream, be positioned at the outside around two the horizontal ends along flexible sheet material member 143a, contact with h3 with the retaining part h1 of the inboard of the recessed portion 143b1 of flexible sheet material retaining member 143b.Thereby flexible sheet material member 143a is kept with stable manner by recessed flexible sheet material retaining member 143b, even without bonding or another element supporting arranged.Be noted that flexible sheet material retaining member 143b can by suitable flexible material for example plastics, metal etc. make so that basically not according to the distortion of the elastic force of flexible sheet material member 143b.

Yet in this example, in order to allow simple connection, as mentioned above, flexible sheet material member 143a is not connected to flexible sheet material retaining member 143b, but the second contact portion B1 and B2 be for retaining part h1 and h2, two or a connection.In addition, can use any fixed cell rather than bonding.Under these circumstances, can realize the advantage identical with this example.

In this example, as flexible sheet material member 143a, adopt polyurethane rubber with 70 ° of JIS-A hardness.In addition, in this example, flexible sheet material member 143a is the sheet element with thickness 0.4mm and width 12.5mm.In addition, the longitudinal length of flexible sheet material member 143a is arranged to that the longitudinal length with developer roll 141 is identical substantially.Flexible sheet material member 143a is accommodated in the recessed portion 143b1 with width 5.0mm of flexible sheet material retaining member 143b, forms U-shaped thus.

In this example, urethane rubber is as the flexible member (flexible material) that constitutes flexible sheet material member 143a, and in addition, other flexible member for example silicon rubber, NBR etc. or rubber flexible member can be used for obtaining same advantage.

In this example, to be arranged to by the setting amount of pushing be that to set contact pressure be 20KPa to 0.8mm to the contact condition between flexible sheet material member 143a and development sleeve 141.It is also noted that the amount of pushing is the imaginary lap between the surface of the apical position of flexible sheet material member 143a and development sleeve 141.

Now, the pressure distribution (contact pressure distribution) in the clamping part (contact clamping part) of the contact area of conduct between development sleeve 141 and flexible sheet material member 143a shown in Figure 23.As shown in figure 23, in this example, form two peaked contact pressures that comprise contact pressure and distribute.That is to say that this contact pressure distribution forms the maximal value of the contact pressure at the upstream and downstream place on the apparent motion direction that is included in development sleeve 141, and comprises the low contact pressure zone of locating in the central.

In the 4th embodiment, the following measurement of carrying out the contact pressure distribution.Adopt the variation of strain-ga(u)ge measurement with the electric signal measurement contact stress.Particularly, the strainmeter of being made by Kyowa ElectronicInstruments Co.Ltd. " KFG-02-120 " is connected in the hole that is arranged in the hollow acrylic acid roller, and this hollow acrylic acid roller has the diameter identical with development sleeve.At this moment, the top of the resin base portion of strainmeter is connected so that give prominence to the scope of 0.1-0.3mm from the surface of acrylic acid roller.In addition, the lead of strainmeter makes roller rotate from the end that hollow space is extracted road acrylic acid roller out thus.Contact with adjustment means in case connect the acrylic acid roller of strainmeter on it, and be rotated, the top of the resin base portion of strainmeter is out of shape by the contact pressure that receives from adjustment means.Thereby utilization can detect the variation of contact pressure as the electric signal of the variation of the dependent variable of strainmeter self.At this moment, in order to reduce the noise of electric signal, contact with developer roll 3 and the member that contacts with development sleeve 3 is removed." PCD-300A " that made by Kyowa Electronic Instruments Co.Ltd. is used to measure electric signal.

Be noted that think contact clamping part n be meant on the apparent motion direction of development sleeve from the contact starting position between adjustment means and development sleeve of upstream side to zone at the contact end position in downstream.Under the situation of a plurality of local maximums, for the contact clamping part n from the contact starting position to the contact end position, the zone that can exist adjustment means wherein not contact with development sleeve with contact pressure.

In this 4th embodiment, following measurement is for the contact pressure (absolute value) of the whole contact clamping part n of the contact area of conduct between adjustment means and development sleeve.The normally used measuring method that is used for contact pressure is for using pressure transducer as the fine sheet shape (for example, by the pressure-sensitive film of Fuji Film Corporation manufacturing etc.).In this example, contact pressure is very low, and very difficult with the UP sensor measurement.Therefore, the measurement of contact pressure is by stainless three layers of stacked together the carrying out of hard material H of the SUS304 that will have thickness 20 μ m, be inserted into the contact portion between adjustment means and development sleeve, with spring balance the central authorities of thin plate along the linear direction that contacts from surface of contact are pulled out thin plate, and measure its pullout forces.Thereby, under the situation that known load is set on the means of pressure measurement, from contact pressure from trial value and contact width obtain the measured value of contact pressure.

The reason that below will to why forms a plurality of contact peak values in the scope according to the contact clamping part n of this example on contact pressure distributes is described.

Shown in Figure 21 A, when in case development sleeve 141 is pushed into the flexible sheet material member 143a of U-shaped supporting, flexible sheet material member 143a contacts with developer roll 141 in the flexible part office, and this flexible portion has hollow space (hollow state) Z that forms in the central portion office of U-shaped.Middle body 143a1 contacts with development sleeve 141 in the outside transversely of flexible sheet material member 143a substantially.At this moment, elastic force is formed by the flexible sheet material member 143a of distortion, thereby can realize being provided with the contact pressure that is used for being adjusted in the toning dosage on the development sleeve 141.That is to say that shown in Figure 21 A, at this moment, flexible sheet material member 143a receives the pressure F-2 from development sleeve 141 at a P2 place.

Be developed sleeve 141 by flexible sheet material member 143a at a P2 place and push, flexible sheet material member 143a is tending towards launching along the direction identical with elastic force, and this elastic force is tending towards making the state restoration that is bent to U-shaped in the horizontal end sides P1 and P2.Yet the distortion of the direction that is tending towards launching along flexible sheet material member 143a is regulated by the retaining part h1 and the h2 of the inside surface of the recessed portion 143b1 of flexible sheet material retaining member 143b.

Thereby flexible sheet material member 143a comprises first contact portion and second contact portion, and this first contact portion contacts with development sleeve 141, and this second contact portion contacts with h2 with retaining part h1.Elastic force is formed by flexible sheet material member 143a, flexible sheet material member 143a likes that first contact portion contacts with development sleeve 141 and/or contacts with h2 with retaining part h1 in second contact portion, thereby flexible sheet material member 143a is by retaining part h1 and h2 and retaining member 143b supporting.

Now, shown in Figure 22 A, consider with reference to being removed with the arch section under the state of U-shaped supporting at flexible sheet material member 143a.Arch section is outwards not outstanding from the framework shown in the dotted line (with the imaginary point slip among Figure 22 B and Figure 22 C) usually.Reason is the both ends 143a2 of sheet material retaining part 143b control flexible sheet material member 143a and the expansion of 143a2.Width W by the framework shown in dotted line and the imaginary point slip is roughly the recess width of the recessed portion 143b1 of flexible sheet material retaining part 143b, and is constant.In addition, the height H of framework is as shown in the imaginary point slip among Figure 22 B and Figure 22 C, along with the increase of the amount of pushing of development sleeve 411 and reduce.On the other hand, the length of the curved portions of the taking-up of flexible sheet material member 143a need keep constant, and with irrelevant by the variation of the frame size shown in the imaginary point slip.

Shown in Figure 22 B, under the little situation of the amount of pushing of development sleeve 141, the flexible sheet material member 143a that is pushed by development sleeve 141 makes itself distortion deviating from according to the space S as dash area, and the length of arch section remains unchanged.

Next, shown in Figure 22 C, under the situation of the amount of the pushing overdetermination amount of development sleeve 141, in the middle of the dash area space S was sandwiched in, thus, being developed the flexible sheet material member 143a that sleeve 141 pushes can not ownly be out of shape to deviate from.Therefore, towards above-mentioned hollow space Z self-deformation, the length of arch section keeps constant to flexible sheet material member 143a thus in the central portion office of arch section.At this moment, since the compressive load of the elastic force that receives from retaining part h1 and h2 act on the arch section of flexible sheet material member 143a.Compressive load surpasses wherein the limit load that occurs fold in the central authorities of the arch section of flexible sheet material member 143a.Subsequently, flexible sheet material member 143a with 141 the contacting of development sleeve that occurs under the state of fold.

Therefore, shown in Figure 21 B, the contact clamping part between development sleeve 141 and flexible sheet material member 143a has: contact area A1, its along the surperficial moving direction of development sleeve 141 in upstream portion; Zone A3, wherein contact pressure is lower in centre; Flaccid part V; Contact pressure A2 in the downstream part.Usually, at contact clamping part C place, the space C that the flexible sheet material member 143a of regional A3 does not contact with development sleeve 141 is formed between flexible sheet material member 143a and the development sleeve 141.Be noted that in regional A3, there is such situation that flexible sheet material member 143 is to contact with development sleeve 141 under contact area A1 and the low contact pressure of A2 of second contact portion likening to.Subsequently, in regulating device 143, form the contact pressure that comprises two peaked contact clamping part n and distribute with structure as shown in figure 23.That is to say that this contact pressure distributes and is positioned at the maximal value of the upstream and downstream of clamping part n on the surperficial moving direction that is included in development sleeve 141, and is included in the lower zone of pressure, central portion office of contact clamping part n.

In addition, in this example, for the relation of the magnetic flux distribution of magnetic roller 142 shown in Figure 20, flexible sheet material member 143a with contact clamping part n contact in θ=65 to 83 degree.That is to say that the peak of immediate magnetic pole is outside the contact clamping part n between development sleeve 141 and the flexible sheet material member 143a.In addition, the peak value of immediate magnetic pole is at the downstream part of the contact clamping part n between development sleeve 141 and flexible layer member 143a on the apparent motion direction of development sleeve 141.

Example 6

Adjustment means: U-shaped sheet element, contact pressure: two peak values, immediate magnetic pole: the upstream of clamping part.

This example is consistent basically with example 5, but for the relation of the magnetic flux distribution of as shown in figure 20 magnetic roller 142, difference is: developer roll 141 contacts with flexible sheet material member 143a to the contact clamping part n places of 30 degree in θ=12.That is to say, in example 5, immediate magnetic pole is set at outside the contact clamping part n, but near the peak of the magnetic pole upstream at the contact clamping part n between development sleeve 141 and flexible layer member 143a on the apparent motion direction of development sleeve 141.

Example 7

Adjustment means: pipe component, contact pressure: two peak values, immediate magnetic pole: the downstream of clamping part.

Figure 24 illustrates the schematic cross sectional views according to the regulating device 143 of this example.Comprise as the seamless flexible pipe member 143c of adjustment means with as the flexible pipe retaining member 143b that comprises in the face of the retaining member of the recessed portion 143b1 of development sleeve 141 according to the regulating device 143 of this example.

Flexible pipe member 143c is added in the recessed portion 143b1 of flexible pipe retaining member 143b.As the flexible pipe member 143c of tubular element axially and development sleeve 141 vertically substantially parallel.That is to say that regulating device 143 is provided so that the vertically substantially parallel of whole vertical and development sleeve 141.

Flexible pipe member 143c comprises flexible portion A1 and A2, and they are contacting with development sleeve 141 on the outside surface that exposes from recessed portion 143b1 of development sleeve 141.Subsequently, the second contact portion B1, B2 and B3 contact with h3 pressure with retaining part h1, the h2 of the recessed portion 143b1 inboard of flexible pipe retaining member 143b in recessed portion 143b1 respectively.The second contact portion B1 and B2 are the upstream side on the apparent motion direction of development sleeve 141 of flexible pipe member 143c and the outside surface on following right side.In addition, the second contact portion B2 is the center of the hollow space Z by flexible pipe member 143c and the outside surface of development development sleeve 141 opposite sides.

Flexible pipe member 143c by with stable manner by concave shape flexible pipe retaining member 143b supporting, and do not have bonding or by another element supporting.Yet flexible pipe member 143c can be fixed to flexible pipe retaining member 143b by adopting for example bonding grade of any fixed cell

In this example, form by silicone rubber as the circumferential member of flexible pipe member 143c, and have the diameter of 5mm and the thickness of 0.5mm, and the 60 degree hardness of JIS-A.Subsequently, flexible pipe member 143c is received by the recessed portion 143b1 of the width W with 5.2mm of flexible pipe retaining member 143c.

For the flexible material (flexible member) that is made of flexible pipe member 143c, except silicone rubber, flexible member for example urethane rubber, NBR etc. or preferred rubber flexible material can be used to obtain identical advantage.

In this example, to be set to by the setting amount of pushing be the contact pressure that 0.8mm obtains 20Kpa to the contact condition between flexible pipe member 143c and development sleeve 141.What note is that the amount of pushing is the imaginary lap between the surface of the apical position of flexible pipe member 143c and development sleeve 141.

For the pressure distribution in clamping part n (contact pressure part), wherein development sleeve 141 contacts with flexible pipe member 143c, as example 5, forms two peaked contact pressures that comprise contact pressure and distributes.Particularly, this contact pressure distributes and comprises along the apparent motion direction of development sleeve 141 maximal value in the contact pressure at upstream and downstream place, and comprises and locate the lower zone of contact pressure in the central.

In addition, in this example, the contact portion between flexible pipe member 143c and development sleeve 141 is set to identical with example 5.Particularly, for the relation of the magnetic flux distribution of as shown in figure 20 magnetic roller 142, flexible pipe member 143c contacts with development sleeve 141 on the contact clamping part n of θ=65-83 degree.That is to say that the peak of hithermost magnetic pole is outside the contact clamping part n between development sleeve 141 and the flexible pipe member 143c.In addition, the peak value of hithermost magnetic pole is in the downstream of the contact clamping part n between development sleeve 141 and flexible pipe member 143c on the apparent motion direction of development sleeve 141.

Example 9

Adjustment means: U-shaped sheet element; Contact pressure: two peak values; Immediate magnetic pole: in clamping part.

This example is consistent basically with example 5, but difference is: developer roll 141 contacts with flexible sheet material member 143a to the contact clamping part n place of 98 degree in θ=80.Therefore, in this example, magnetic pole is positioned at contact clamping part n.

Comparative example 9

Adjustment means: U-shaped sheet element, contact pressure: two peak values, immediate magnetic pole: the downstream of clamping part

Figure 29 illustrates the schematic cross sectional views according to the regulating device 142 of this comparative example.Consistent with the regulon that example 5 is described basically according to the regulating device 143 of comparative example, but development sleeve 141 is set at 0.3mm for the amount of pushing of flexible sheet material member 143a.According to this amount of pushing, when adopting the paper identical, be difficult to obtain to be used for to reduce toner on development sleeve 141 to obtain fully thin layer required contact pressure with example 5.Therefore, in this comparative example, as flexible sheet material member 143a, best contact pressure realizes by using than the thick paper of paper in example 5.In this comparative example, identical with example 5, contact pressure is set at 20KPa.

Particularly, in comparative example, flexible sheet material member 143a has adopted the thickness with 1.0mm, 70 urethane rubbers of spending hardness of JIS-A.Flexible sheet material member 143a length in the horizontal is 12.5mm in addition, and flexible sheet material member 143a is received by the recessed portion 143b1 with 5.0mm width W of flexible pipe retaining member 143b, forms U-shaped thus.

Flexible sheet material member 143a according to this comparative example has than sheet thickness thick in example 5, thereby elastic force is bigger.Therefore, contact with surface at development sleeve 141 with the flexible sheet material member 143a of U-shaped supporting, the curvature that development sleeve 141 is in its curved surface with do not have the curvature under the state of contact identical at flexible sheet material member 143a and development sleeve 141.Under these circumstances, the fold of flexible sheet material member 143a does not occur, thereby with during the contact pressure that contacts clamping part n place of development sleeve 141 distributes, formation comprises that a peaked contact pressure distributes, and this maximal value makes along the apparent motion direction of the development sleeve 141 contact pressure maximum in the central part office of contact clamping part n.

In addition, in comparative example, according to the relation of the magnetic flux distribution of as shown in figure 20 magnetic roller 142, be θ=70 degree at the contact position between flexible sheet material member 143a and the development sleeve 141 (core of the contact clamping part n on the apparent motion direction at developer roll 141).

Comparative example 10

Adjustment means: scraper plate shape

Figure 30 shows the diagrammatic cross-sectional surface construction of the imaging device 200 that has adopted developing apparatus 104B, and developing apparatus 104B comprises the regulating device 143 according to this comparative example.In Figure 30, omission is given comprising and the element identical functions of the imaging device 100 shown in Figure 19 and element or their IF-AND-ONLY-IF element and their detailed description of structure of same reference numerals.

In this comparative example, regulate scraper plate 143d quilt by the supporting metal sheets 146 that is fixed to developer container 145 side bearing along the longitudinal as scraping of adjustment means tabular (tabular).Regulate scraper plate 143d can be substantially by flexible member for example urethane rubber etc. make.Regulating scraper plate 143d contacts with development sleeve 141 with the downside in the face of part of developer roll 141.

In this comparative example, use has the supporting metal sheets 146 of 1.2mm thickness, urethane rubber plate with 0.9mm thickness is adhered on the supporting metal sheets 146 as adjustment means 143d, from along the urethane rubber plate vertically on a side supporting part to the distance of the contact portion of development sleeve 141, promptly, free distance is 6.5mm, and is 3.1mm to the amount of pushing of the urethane rubber of development sleeve 141.In this comparative example, in example 5, contact pressure is set at 20KPa.

In addition, under the situation of this spline structure, in the contact pressure of regulating the contact site office between scraper plate 143d and the development sleeve 141 distributes, formation comprises that a peaked contact pressure distributes, and this maximal value makes along the apparent motion direction of the development sleeve 141 contact pressure maximum in the central part office of contact clamping part n.

In addition, under the situation of comparative example, according to the relation of the magnetic flux distribution of the magnetic roller 142 shown in Figure 20, be that θ=70 are spent at the contact position of regulating between scraper plate 143d and the development sleeve 141 (core of the contact clamping part n on the apparent motion direction at developer roll 141).

Comparative example 11

Adjustment means: sheet metal+U-shaped tension force sheet material (clamping part wider width)

Figure 31 illustrates the schematic cross-section structure according to the regulating device 143 of this comparative example.Regulating device 143 according to this comparative example comprises: flexible sheet material member 143a, as adjustment means; Flexible sheet material retaining member 143e is as the adjustment means retaining member.In case relatively, this comparative example is with the difference of example 5 between comparative example and example 5: when supporting U-shaped flexible sheet material member 143, two the end 143a2 transversely of flexible sheet material member 143a and the side of 143a2 are not supported.Flexible sheet material member 143a goes up and is supported by the side P1 of two end 143a2 and 143a2 and P1 being adhered to flexible sheet material retaining member 143e.Identical in flexible sheet material member 143a self and the example 5.Flexible sheet material retaining member 143e adopts the sheet member.

State when Figure 31 A shows development sleeve and is not pushed into respect to the flexible sheet material member 143a with the U-shaped supporting.In addition, Figure 31 B shows the state when development sleeve 141 is pushed with respect to the flexible sheet material member 143a with the U-shaped supporting.

Shown in Figure 31 A and 31B, flexible sheet material member 143a contacts with development sleeve 141 in the flexible part office, and this flexible portion comprises with hollow space (hollow state) Z of U-shaped in middle body formation, receives pressure F-2 thus.Under the situation of this spline structure, flexible sheet material retaining member 143e does not regulate the both sides of flexible sheet material member 143a, thereby even under the situation that the amount of pushing of development sleeve 141 increases, flexible sheet material member 142a can launch along the direction perpendicular to pressure F-2.Therefore, under the situation of this spline structure, for example, though the amount of pushing of development sleeve 141 be set at example 5 in identical situation under, the fold of flexible sheet material member 143a is not easy to form.With the contact pressure part that contacts clamping part n place of development sleeve 141 in, formation comprises that a peaked contact pressure distributes, and this maximal value makes along the apparent motion direction of the development sleeve 141 contact pressure maximum in the central portion office of contact clamping part n.Under the situation of this comparative example, identical with example 5, contact pressure is set at 20KPa.

In addition, in comparative example, according to the relation of the magnetic flux distribution of as shown in figure 20 magnetic roller 142, be θ=70 degree at the contact position between flexible sheet material member 143a and the development sleeve 141 (middle body of the contact clamping part n on the apparent motion direction at developer roll 141).

Be noted that conduct and structure like this example class, in Japanese publication No.11-265115, disclosed a kind of developing apparatus.

Comparative example 12

Adjustment means: a plurality of scraper plates

Figure 32 illustrates the schematic cross-section structure according to the regulating device 143 of this comparative example.Regulating device 143 according to this comparative example comprises: the first cockscomb 143g; The second cockscomb 143h, it is vertically along side bearing thin type flexible member phosphor bronze etc. for example.The second cockscomb 143h makes its downside with respect to development sleeve 141 of facing part contact as first and second adjustment means with development sleeve 141.The second cockscomb 143h is arranged in the downstream of the first cockscomb 143g along the apparent motion direction of development sleeve 141.Thereby, have such structure according to the regulating device 143 of this comparative example, that is, first and second adjustment means are used in two part places and contact with development sleeve 141.

In this comparative example, each contact portion of the first cockscomb 143g and the second cockscomb 143h and development sleeve 141 comprises that contact pressure distributes, and wherein the apparent motion direction along development sleeve 141 forms a maximal value in the central portion office of contact clamping part.Under the situation of this comparative example,, provide along the apparent motion direction of development sleeve 141 to comprise that two peaked contact pressures of contact pressure distribute as regulating device 143 all-in-one-pieces.With respect to first and second cockscomb 143g and the 143h, contact pressure is set at 20KPa.

In addition, under the situation of comparative example, according to the relation of the magnetic flux distribution of as shown in figure 20 magnetic roller 142, contact position between the first cockscomb 143g and development sleeve 141 is θ=-30 degree, and the contact position between the second cockscomb 143h and development sleeve 141 is θ=-68 degree.Each is middle position on the apparent motion direction of the development sleeve 141 of contact clamping part n for its contact position.

Be noted that conduct and the similar structure of this comparative example, in Japanese publication No.6-95484, disclose a kind of developing apparatus.

Comparative example 13

Adjustment means: the scraper plate of a plurality of and edge contact

Figure 33 shows the schematic cross sectional views according to the regulating device 143 of this comparative example.Comprise cockscomb 143i according to the regulating device 143 of this comparative example as adjustment means.Particularly, cockscomb 143i, it contacts with development sleeve 141, is included in the arc-shaped depression portion K of contact site office.When the hypothesis development sleeve 141 radius be r, the radius-of-curvature of recess k is R, such structure satisfies the relation of 0＜R≤r.At this moment, two of the arc-shaped depression portion K of cockscomb 143i marginal portions contact with development sleeve 141.

Under the situation of this spline structure, the contact clamping part n between development sleeve 141 and cockscomb 143i comprises following each zone.Being included in this zone that engages in the clamping part is: the first edge contact part 143i1 in the upstream portion office that contacts clamping part n, and this zone contacts with development sleeve 141 at the middle body (that is recessed portion k) of clamping part n; The second edge contact part 143i2 in the downstream portion office that contacts clamping part n.

Be distributed as the contact pressure that comprises a zone according to the contact pressure of this comparative example at contact clamping part n place and distribute, contact pressure partly comprises: a zone, and contact pressure does not appear at the central authorities of contact clamping part n in this zone; Two maximal values, it is included in the precipitous peak contact pressure that first edge contact part and second edge contact are partly located.At the whole 29KPa that is set at of the contact pressure at cockscomb 143i place.

In addition, under the situation of this comparative example, according to the relation of the magnetic flux distribution of as shown in figure 20 magnetic roller 142, contact position between the first edge contact part 143i1 and development sleeve 141 is θ=68 degree, and the contact position between the second edge contact part 143i2 and development sleeve 141 is θ=73 degree.

Be noted that conduct and the similar structure of this comparative example, in Japanese publication No.6-95484, disclose a kind of developing apparatus.

Example 8

Adjustment means: U-shaped sheet element, edge side are fixed, the U-shaped drag board; Contact pressure: two peak values (forming); Immediate magnetic pole: the downstream of clamping part

Figure 25 A and 25B show the schematic cross-section structure according to the regulating device 143 of this example.According to the adjusting of this example or 143 and comparative examples 11 similar, but difference is following aspect.That is to say that under the situation of this example, the polyurethane sheet that is under the state that wherein forms flaccid part V in advance is used as flexible sheet material member 143f.

As an example of special-purpose sheet manufacturing method, the method that is used for forming flaccid part can promptly, by carrying out timeliness and drying, be used finishing sheet material casting mold (the following sheet molding) extruded threads of diameter 0.5mm simultaneously with reference to following method.

Originally be exemplified as the example that wherein forms flaccid part V in advance, even but under the situation that adopts the flexible member that forms a plurality of flaccid part V in advance, can provide the advantage identical with this example.

Under the situation of this example, it is that 0.8mm makes that contact pressure is 20KPa that the contact conditions between flexible layer member 143f and development sleeve 141 is set to by the setting amount of pushing.When the pressure distribution (contact pressure distribution) in development sleeve 141 and contact clamping part n that flexible sheet material member 143f contacts at this moment, form and comprise that two peaked contact pressures of contact pressure distribute, shown in example 5.That is to say, this contact pressure maximal value of contact pressure at upstream and downstream place of the apparent motion direction that is included in development sleeve 141 that distributes, and comprise wherein the less zone of contact pressure in the central.In addition, under the situation of this example, the contact position between flexible sheet material member 143f and development sleeve 141 is set in the mode identical with example 5.That is to say, according to the relation of the magnetic flux distribution of as shown in figure 20 magnetic roller 142, flexible pipe member 143c contacts with development sleeve 141 at the contact clamping part place of θ=65-83 degree, in other words, the peak of close magnetic pole is located at outside the contact clamping part n between development sleeve 141 and the flexible pipe member 143c.In addition, the peak value of hithermost magnetic pole is located at the downstream part of the contact clamping part n between development sleeve 141 and flexible sheet material member 143f on the apparent motion direction of development sleeve 141.

[image evaluation method of example and comparative example]

Carry out the picture appraisal test by the imaging device that adopts developing apparatus, this developing apparatus has the adjustment means 143 according to example 5-9 and above-mentioned comparative example 9-13.

(a-1) original negative ghost image

The solid picture of output Cmax level, wherein black is printed on the whole surface of imaging region of transfer materials P, and logical Macbeth densitometer RD-1255 measures the optics reflection density.Particularly, in the concentration of image apex part (first lap of development sleeve 141) by five position probing, and calculate their mean value, subsequently development sleeve 141 in the concentration of second circle by five position measurements, and calculate their mean value, obtain concentration difference △ (delta) thus, and estimate according to following standard.

A: concentration difference △ is lower than 0.3.

C: concentration difference △ is more than or equal to 0.3

Be lower than 0.3 but find that the evaluation result under the situation of minimal negative ghost image is called as B at concentration difference △.After and then handle box is placed on the imaging device main body, print 1 00 and stop using 8 hours subsequently after, carry out the concentration evaluation.By printing test with horizontal document image continuously with picture rate 5%.

(a-2) reason of original negative ghost image

Negative ghost image is at two circles of development sleeve 141 or the image error that reduces concentration after the multi-turn more, when printing solid picture, wherein concentration is only corresponding to being high on a circle of the development sleeve 141 of the direction of the apparent motion direction (sense of rotation) of developer roll 101.That is to say that in this example, negative ghost image is an image error, wherein the concentration of solid black image is high (circle of developer roll 141) at transfer materials P with respect to the leading edge of the direction of transfer of transfer materials P, and the concentration of solid black image reduces subsequently.Do not have afterwards under the situation of print paper of sufficient amount and then placing handle box (hereinafter referred to as initial), the toner in developer reservoir 145 is not nearly all for the required electric charge that develops.Reason is that handle box 109 stopped using for a long time, and is in such state, that is, the toning dosage in developer reservoir 145 is high, does not carry out toner is applied the processing of electric charge.

Yet concentration circle for development sleeve 141 during the printing of solid black color image is very high, and can form the toner layer with appropriate charge.Reason is, along with the regulon that is used for the toning dosage on the development sleeve 141 by consuming any toner several times and not, on development sleeve 141, form toner coating.Now, toner is that by the reason that the toner regulon consumes any toner several times and not development sleeve 141 is in non-printing rotation in period.Therefore, even under the very low situation of the toning dosage in toner container 145, perhaps be applied under the very low situation of electric charge on the toner, the chance of frictional electrification increases, and can obtain sufficient charge thus.

On the other hand, during the solid black color image is printed second circle reduce with and development sleeve 141 on concentration reduce.Then, below reason will be described.That is to say, during rotation before, in developing regional, consume toner.In addition, along with the toner in developer reservoir 145 by the up-to-date development sleeve 141 that is applied to, this toner has the low electric charge that does not wherein almost have electric charge, toner only by regulon once.Thus, the toner with the low electric charge that does not almost apply electric charge can not obtain sufficient charge, has reduced development efficient thus.

In other words, can imagine with corresponding to development sleeve 141 one the circle toner coating compare, two the circle with and subsequent toner charge lower, can not obtain suitable electric charge, that is to say, during the solid black color image is printed because concentration difference appears in the development efficient that reduces.

(b-1) positive echo during the printer paper number increases

The supply of the developer on development sleeve 141 and scratch are evaluated with respect to the development ghost image.Consider peripheral speed and its processing speed of development sleeve 141, estimate the positive echo that in the rotation circulation of development sleeve 141, occurs.Particularly, in that Yan Kecong visually observes the concentration difference of appearance in the first lap rotation circulation of development sleeve 141 for sentence 5mm square and the foursquare filled black square of 25mm to print the half tone image of repairing image at the leading edge of transfer materials P.For each example is utilized 600dpi laser beam flying instrument at printer, and the carries out image record.Utilize current evaluation, half tone image means candy strip and represents shadow tone concentration as a whole, has wherein write down a line on main scanning direction in this candy strip, does not write down four lines thereafter.

Here, carry out its picture appraisal with following standard.

D: after a circle or multi-turn development sleeve, print in the half tone image process, in two repairings, observe the concentration difference of half tone image.

C:, in one of repairing, observe the concentration difference of half tone image only printing in the half tone image process after the circle development sleeve.

B:, do not observe the concentration difference of half tone image, but in one of repairing, observe some noises only printing in the half tone image process after the circle development sleeve.

A: in arbitrary repairing, all do not observe concentration difference.

After 4000 pages printing test, carry out and estimate.Carry out printing test by printing horizontal document image constantly than (print over) with 5% image.

(b-2) in type face counting increase process, cause the positive virtual image

Weakened body resistance similarly is image error, wherein when being right after to print such as solid black figure high print over like this when printing half tone image after repairing image, corresponding to the half tone image concentration of repairing the image print part and compare comparatively high corresponding to the half tone image concentration of the part of not printing the repairing image.In other words, weakened body resistance similarly is image error, wherein concentration difference occurs in the half tone image that comes the autography course, and when error was extremely bad, the concentration difference of repairing form may occur in the rotation circulation of development sleeve 141.

The mechanism that occurs the positive virtual image when increasing the type face counting will be described now.When toner charge the amount toner coating on the development sleeve 141 and the toner in developer reservoir 145 in non-print procedure be right after be supplied to again after printing development sleeve 141 afterwards between the toner coating on the development sleeve 141 not simultaneously, the positive virtual image appears.Hereinafter this point will be described more specifically.

As the process that is used to form half tone image, dislocation charge (charged toner) makes and to be minimized in poor corresponding to the surface potential of the surface potential of the photosensitive drums 101 of half tone image and development sleeve 141.That is to say to have the toner of electric charge by moving, to become equilibrium state from the static nonequilibrium condition thus and form half tone image.

Thereby, when the toner charge amount of toner coating in non-print procedure be right after after printing when variant, difference appears in the toner amount of movement near the process of electrostatic equilibrium state.Therefore, this difference shows as the concentration difference of half tone image in image.

In non-print procedure, the toner on the development sleeve 141 is under the state that is not consumed, and the toner that applies the surface of development sleeve 141 thus keeps easily in advance.Therefore, the number of times of triboelectric charge increases because toner repeatedly passes regulon, so generate the toner with excessive charge easily.When the toner with excessive charge increases, can be with more a spot of toner near the electrostatic equilibrium state.That is to say that half tone image concentration reduces.

On the other hand, utilize the lip-deep toner coating that is right after development sleeve 141 after printing, the toning dosage with excessive charge reduces.This be because for the toner that is supplied to development sleeve 141 from developer reservoir 145 again only once chance obtain triboelectric charge at regulon.That is to say, thereby because being arranged, the toner that has excessive charge on a small quantity dwindles poor corresponding to the surface potential of the surface potential of the photosensitive drums 101 of half tone image and development sleeve 141, so be necessary mobile relatively large toner so that guarantee the electric charge amount of movement.Therefore, increase the concentration of half tone image.

In addition, when the type face counting increased, the positive virtual image often worsened.Usually, the particle diameter of the toner that consumes easily is centered at around the average scale diameter.Therefore, when the type face counting increases, often generate than the wideer particle diameter of initial average particulate diameter distribution.The quantity of electric charge of having known the toner relevant with particle diameter diminishes along with particle diameter and trends towards the enhanced charge amount.Why think like this that the number of times that contacts is just many more because the particle diameter of toner is more little.

In other words, when the type face counting increased, the toner-particle diameter Distribution broadened.Broadening like this makes the toner that has than small particle diameters have excessive charge.In addition, excessive charged toner that is to say, has the toner of excessive charge amount, has big reflectivity for development sleeve 141, and on the easier surface that remaines in development sleeve 141.Therefore, the toner that has than small particle diameters and excessive charge amount remaines in non-print procedure on the development sleeve 141 easily, and the concentration of half tone image reduces thus.

Thereby, in order to suppress the positive virtual image, importantly, remain on the development sleeve 141, prevent to have of the increase of the toner of excessive charge amount thus at the regulon place by between the toner of charge image developing toner in developer reservoir 145 that keeps, suitably switching inhibition formulation toner.Alternatively, even generate the toner with excessive charge amount, the discarded development toner that keeps remains important.

For example, as mentioned above, utilize the feed rolls that provides on the developing apparatus so that the slip developer roll is a kind of in order to non magnetic single component developer (nonmagnetic toner) is supplied to the known technology of developer roll, such as disclose the known technology that proposes in 54-43027 number in Japanese patent unexamined.The toner of such feed rolls discarded reservation in supplying toner is so that prevent to produce the development course.Therefore, under the situation of utilizing such developing apparatus, even toner charge polarity changes in time or along with environmental change, the still switching of toner for this reason, thereby the positive virtual image is being not easy to occur.

On the other hand, particularly, utilize following developing apparatus, promptly except regulating parts, be not used in the slide unit of development sleeve 141 and magnetically carry out supplying toner to development sleeve 141, the discarded charge image developing toner that keeps is difficult physically for feed rolls, and the positive virtual image more may occur when increasing the type face counting.

(c) the vertical density unevenness when increasing the type face counting is even

By on whole page or leaf, printing the filled black image at output filled black image on the whole page or leaf and visually estimate to spare to carry out when increasing the type face counting and spare relevant picture appraisal with vertical density unevenness at the density unevenness whether strips is arranged on the longitudinal direction (laser main scanning direction).Notice that longitudinal direction is the longitudinal direction of photosensitive drums 1, development sleeve 141, regulating device 143 etc., and with the direction of the carriage direction quadrature that transmits material P on.

C: observe concentration uneven five or multi-ribbon shape more.

B: observe uneven at least two of concentration and still be less than five band shapes.

A: observe concentration uneven one or band shape still less.

After 4000 pages of test printing, carry out the uneven evaluation of vertical concentration.Carry out printing test by image than printing horizontal document image constantly with 5%.

[picture appraisal result]

The evaluation result of each example and comparative example has been shown in table 2.Hereinafter further describe this routine advantage with reference to the result of picture appraisal shown in the table 2.

Table [2]

		Vertical concentration inequality when the type face counting increases	The original negative virtual image	The positive virtual image when type face counting increases
					Example	Example 5	B	B	A
Example 6	B	C	B
				Example 7		C	B	B
Example 8	C	B	B
				Example 9		C	B	D
Comparative example	Comparative example 9	D	C						C
				Comparative example 10	D	D	D
	Comparative example 11	D	B					D
				Comparative example 12	D	B	D
	Comparative example 13	D	B					D

(1) this routine superiority relevant with foliated adjusting parts

Regulate with regard to the comparative example 10 of parts with regard to utilizing in a longitudinal direction, the positive virtual image when increasing the type face counting, occurs along the foliated lamellar of the accommodating plate-shaped paper of a side.Regulate the toner on the development sleeve 141 one time, thereby be applied for low the electric charge of toner.Similarly, regulate owing to only carry out once, so the toner container on the development sleeve 141 is subject to the history effect of developing.As a result, the original negative virtual image and the easier appearance of the positive virtual image when increasing the type face counting.

In addition with regard to comparative example 10, the easier appearance of vertical concentration inequality when increasing the type face counting.Contact pressure changes linearly, thereby the variation of contact pressure occurs easily.As a result, when printing wherein the different image of vertical print over, it is unequal that contact pressure becomes in a longitudinal direction, and bus concentration inequality occurs.

On the other hand, with regard to this example, can suppress to take place the initial positive virtual image, the positive virtual image when increasing the type face counting and vertical concentration inequality significantly.

(2) for this routine superiority of each assessment item

Hereinafter will each assessment item be described particularly so that provide this routine superiority.

(2-1) the vertical concentration inequality when increasing the type face counting

To come comparative example 5 to 9 and comparative example 9 to 13 about when increasing the type face counting, suppressing vertical uneven advantage.It is especially favourable in example 5 and 6 to suppress vertical uneven advantage when increasing the type face counting.Hereinafter will describe and utilize this example to realize when increasing the type face counting, suppressing vertical uneven reason.

With regard to example 5 and 6, the contact pressure in the contact clip distributes and has two contact pressure maximal values.Figure 27 A shows the transformation of the deformation state of the flexible paper parts 143a relevant with the increase of the amount of pushing of development sleeve 141.The amount of pushing of development sleeve 141 increases with the pagination of the solid line among Figure 27 A, dot-and-dash line and dotted line.

At first, under the amount of pushing of development sleeve 141 was little situation, shown in solid line, the central portion office of contact pressure contact clip on the surperficial moving direction of development sleeve 141 was at maximum pressure.Then, increase and under the situation that sleeve 141 is out of shape shown in dot-and-dash line among Figure 27 A like that in the amount of pushing of development sleeve 141, slack V appears at the central portion office of contact clip on the surperficial moving direction of development sleeve 141.The peaked position of contact pressure moves to upstream one side and downstream one side on the surperficial moving direction of development sleeve 141 from the middle body of contact clip then.In addition, increase and under the situation that development sleeve 141 is out of shape shown in dotted line among Figure 27 A like that in the development sleeve amount of pushing, the peaked position of contact pressure further moves to upstream one side and downstream one side on the surperficial moving direction of development sleeve 141 from the middle body of contact clip.

The coincidence amount that Figure 27 B shows development sleeve 141 and regulates parts (being flexible paper parts 143a) here.Each coincidence amount of solid line among Figure 27 B, dot-and-dash line and dotted line corresponding to solid line, dot-and-dash line and dotted line state among Figure 27 A.State with the adjusting parts that are out of shape like that shown in Figure 27 A only shows dot-and-dash line.As can be seen, have the fixedly arc of curvature if overlapped in Figure 27 B, then its coincidence amount becomes maximum in the centre of contact position, and one side and downstream one side become less gradually towards the upstream.

Yet, with regard to example 5 and 6, when contact pressure is in maximal value, in the central portion office of contact clip slack V should appear.In addition, as shown in Figure 27 A, wherein contact pressure is upstream one side or downstream one side that peaked position rather than middle body are displaced to less coincidence amount.

Therefore, under the deformation state situation of the dot-and-dash line of Figure 27 A or dotted line, coincidence amount shown in the length of arrow is almost constant among Figure 27 B.As a result, the maximal value of contact pressure does not change pro rata with the increase of the amount of pushing of development sleeve 141, and can be similar to the value of being scheduled to for this reason.

Thereby, even the amount of pushing changes, but can keep predetermined pressure with stable manner on the longitudinal direction of regulating parts, realize the uneven remarkable inhibition of vertical concentration when increasing the type face counting thus.

Particularly, when increasing the type face counting, because the course or the environmental fluctuating of output image according to slowly moving of the adjusting parts that are out of shape, change the amount of pushing easily.Particularly, though be right after and present level after carton is set, in image, occurs, but in contact pressure and under will regulating situation about differently being provided with when parts are attached to developing apparatus, if the type face counting increases, then the difference of the amount of pushing occurs on the longitudinal direction of regulating parts easily.This is because slowly the difference of the speed of movement and deformation occurs easily because the stress that the adjusting parts receive in a longitudinal direction is different.Yet, with regard to example 5 and 6, exist as lower area, in this zone the maximal value of contact pressure and be not in relation to development sleeve 141 the amount of pushing increase and change easily can be kept thus and be in contact with it pressure.Thereby, with regard to example 5 and 6,, still can suppress vertical concentration inequality significantly even increase the printer paper counting.

Because device size reduces, diminish and under the situation that the radius-of-curvature of development sleeve 141 diminishes, above-mentioned coincidence quantitative change is little in addition at the diameter of development sleeve 141.Therefore, according to example 5 and 6, even under the size that reduces, present embodiment is owing to can be scheduled to contact pressure and the tool superiority for this reason.

With regard to example 5 and 6,, can accumulate toner reposefully beyond the contact clip between development sleeve 141 and the adjusting parts in addition so that rotate at slack V place by the nearest magnetic pole of magnetic roller 142 is set.Can suppress tangible toner thus degenerates.

With regard to example 5 and 6, compliant member is used as the adjusting parts in addition, therefore can alleviate to be accompanied by the part increase of toner accumulation to the stress of slack V place toner.Therefore, tangible toner degeneration can be suppressed, and the vertical concentration inequality when increasing the type face counting can be suppressed significantly.

On the other hand, with regard to comparative example 9 to 11, vertical concentration inequality appears when increasing the type face counting.With regard to comparative example 9 to 11, the contact pressure in the contact clip distributes and has a contact pressure maximal value.The maximal value of the contact pressure relevant with the amount of pushing of development sleeve 141 has the Different Slope of deciding on spring constant based on each configuration, but is considered to increase linearly (seeing Figure 26).As a result, on whole longitudinal direction, keep predetermined contact pressure in case in time and stable be difficult, when increasing vertical concentration inequality appears when type face is counted therefore.

At first with regard to comparative example 9 to 11, when reducing device size, the maximal value of contact pressure changes about the amount of the pushing wide cut of development sleeve 141, thus with in time and stable manner is kept predetermined contact pressure and become more difficult.Therefore, easier vertical concentration imbalance appears significantly.

Comparative example 12 and 13 has two maximal values although contact pressure distributes with that, occurs vertical concentration inequality when increasing the printer paper counting.Comparative example 12 is such examples, and wherein the adjusting parts in the comparative example 10 are a plurality of.Yet these adjusting parts of regulating in parts and the comparative example 10 move similarly.That is to say that the maximal value of respectively regulating the contact pressure of parts relevant with the amount of pushing of development sleeve 141 increases linearly.Can envision as its result and vertical concentration inequality when increasing the type face counting, occur.

With regard to comparative example 13, regulating parts is rigidity, therefore is similar to comparative example 10, and the maximal value of the contact pressure relevant with the amount of pushing of development sleeve 141 increases linearly.In addition, the local pressure that increases can not disperse on contact clip sunken inside Partial K place toner, therefore occurs tangible toner easily and degenerates.Can envision as its result and vertical concentration inequality when increasing the type face counting, occur.

Similar in addition and comparative example 9 to 11, comparative example 12 and comparative example 13 also are difficult to when reducing device size with in time and stable manner is kept predetermined pressure.Therefore significant vertically concentration inequality appears.

The unequal evaluation with example 5 of vertical concentration of example 9 compared slightly deterioration with 6 when increasing the type face counting.The reason of this point may be that the peak flux density of magnetic roller 142 is positioned in the contact clip, so toner degeneration upgrading.Particularly, toner easier appearance of degenerating is to accumulate toner because prevented reposefully in the slack between two maximal values of contact pressure in the pressure distribution in contact clip.Therefore, vertical concentration inequality is considered to owing to the variation from the deterioration velocity of toner on the longitudinal direction of regulating parts of time variation or development course worsens when increasing the type face counting.

The unequal evaluation with example 5 of vertical concentration of example 7 compared slightly deterioration with 6 when increasing the printer paper counting.To the reason of this point be described.With regard to example 7, seamless flexible pipe is used as the adjusting parts.Under the situation of as example 5 and 6, utilizing sheet component as the adjusting parts, because the two ends on each sheet broad ways are variable independently, so can alleviate the variation on the longitudinal direction of regulating parts that is accompanied by the development course.On the other hand, utilize seamless flexible pipe, degree of freedom is greater than the degree of freedom of sheet component.The easier distortion of seamless in addition flexible pipe occurs on the longitudinal direction of regulating parts and the variation of contact pressure is easier.Therefore, can envision in example 7, stability in time and example 5 and 6 are in a ratio of low, therefore small vertical concentration inequality may occur when increasing the printer paper counting.

At last, the unequal evaluation with example 5 of vertical concentration of example 8 compared slightly deterioration with 6 when increasing the type face counting.To the reason of this point be described.With regard to example 8, be used as the sheet component of regulating parts and contact with development sleeve 141 under the state that is pre-formed slack B.Therefore, contact stabilization does not in time have example 5 and 6 high like that.The result can envision, and small vertical concentration inequality may occur when increasing the type face counting.

As mentioned above, according to this example, a plurality of local maximums of contact pressure are arranged in the pressure distribution in contact clip, wherein development sleeve 141 and adjusting parts come in contact mutually.Therefore exist as lower area,, therefore can keep the expection contact pressure of adjusting parts with stable manner even the amount of pushing of development sleeve 141 changes and maximum contact pressure is still constant in this zone.As mentioned above, change easily in the amount of pushing of regulating on the longitudinal direction of parts, specifically be because when increasing type face and count from the slow movement and deformation of adjusting parts of output image course or environmental change etc.Therefore, according to this example, maximum contact pressure is not easy to change about the amount of pushing of development sleeve 141, even still like this under the situation that the amount of pushing on the longitudinal direction of adjusting parts changes easily at development sleeve 141.Therefore, can suppress vertical concentration inequality significantly.

In addition according to this example, when reducing device size, no matter how wide cut changes the amount of pushing of development sleeve 141, and the variation of maximum contact pressure all is little.Therefore, can keep being in contact with it pressure, and can suppress vertical concentration inequality significantly.

In addition according to this example, be present in beyond the contact clip with development sleeve 141 and the peak of regulating the magnetic density of the immediate magnetic roller 142 of contact clip between the parts.Therefore, toner can accumulate as the slack V place between the maximal value of contact pressure in the rotation.Therefore, can suppress toner significantly and degenerate, and can suppress vertical concentration inequality significantly.

In addition, by utilizing compliant member as regulating parts, can alleviate the increase that is accompanied by that slack V place toner accumulates to the local stress of toner.Therefore, can suppress toner significantly and degenerate, and can suppress vertical concentration inequality significantly.

(2-2) evaluation of the original negative virtual image and the positive virtual image when increasing the type face counting

To come comparative example 5 to 7, example 9 and comparative example 9 to 13 about the advantage that suppresses the original negative virtual image and the positive virtual image when increasing the type face counting.To the reason that advantageously suppresses the original negative virtual image and the positive virtual image when increasing the type face counting be described about this example.

At first the original negative virtual image will be described.The generting machanism that is used for the original negative virtual image as hereinbefore.With regard to this example, the pressure distribution in the contact clip that development sleeve 141 and adjusting parts come in contact therein has two contact pressure maximal values.Therefore, new toner is supplied to development sleeve 141 in developer reservoir 145 after, for toner, there are two chances charged at the regulon place.As a result, be low toner even toner is the initial charge amount, still may apply suitable electric charge.With regard to this example, the contact clip width itself is widened in addition, thereby is considered to tool superiority on applying property of electric charge.

Therefore with regard to this example, the pressure distribution in the contact clip that development sleeve 141 and adjusting parts come in contact therein has two contact pressure maximal values, and has wide contact clip width, and the applying property of electric charge to toner is high thus.Thereby, even the toner with low initial charge amount still can apply suitable electric charge, and can suppress the original negative virtual image significantly under the state of supply easily.

In other words, according to this example, the pressure distribution in the contact clip that development sleeve 141 and adjusting parts come in contact therein has a plurality of contact pressure maximal values, increases the number of times that triboelectric charge occurs thus, and improves applying property of electric charge.Therefore, such as wherein being provided with under the original state such of type face counting after the carton,, still can apply the predetermined charge amount to toner even just in developer reservoir 15, have under the state of a large amount of toners with low electric charge for low state.Therefore, can suppress the original negative virtual image significantly.

The positive virtual image when increasing the printer paper counting then will be described.The generting machanism that is used for the positive virtual image when increasing the type face counting even this example and particularly example 5 still do not have the virtual image when increasing the type face counting, so is favourable as mentioned above.Its reason will be described.

At first, similar to the inhibition of the negative virtual image, this example and particularly example 5 have superiority on applying property of electric charge.Therefore, can apply suitable electric charge to toner with stable manner.

With regard to example 5, the pressure distribution in the contact clip that development sleeve 141 and adjusting parts come in contact therein has two contact pressure maximal values in addition.Thereby, apply adjusting power for twice to toner, and toner accumulation occurs and become rotation so that be right after before the maximal value of contact pressure.At first, utilization is subjected to the regulon regulated in the maximal value of the surperficial moving direction upstream of development sleeve 141, being shaped as of the toner that is sucked is wide, and the charge image developing toner of toner of supplying again from developer reservoir 145 and reservation is wound into and revolves, and increases changeable property thus.In addition, utilize to be subjected to the regulon regulated in the maximal value of the surperficial moving direction upstream of development sleeve 141, the quantity of toner is regulated by the upstream regulation unit, and the quantity that therefore is expected to the toner regulated is little.Thereby even excessive charged toner is attached to development sleeve 141 by force, this still can discard by the rotation that is right after the toner before maximal value.As a result, but be subjected to the changeable property of the regulon place toner regulated in the maximal value of the surperficial moving direction upstream of development sleeve 141 and the disposability of the regulon that is subjected to regulate in the maximal value in development sleeve downstream improves to some extent.

In addition, having passed the toner that is subjected to the regulon that the upstream maximal value regulated arrives according to the downstream maximal value and regulates parts.In this case, can envision, regulating parts place adjusting toner according to the downstream maximal value, and the toner circulation of not passing the adjusting parts toner accumulation occur thus through the slack V between two maximal values.Therefore, can think and prevented that the toner with weak charge amount from passing.

Figure 28 illustrates the CHARGE DISTRIBUTION of the toner that on development sleeve 141, applies.Figure 28 shows the quantity of electric charge according to unit on transverse axis, and has used the number distribution of measured complete toner counting on Z-axis.Notice the measurement that utilizes Hosokawa Micron E-SPARTANALYSER EST-II to carry out CHARGE DISTRIBUTION.With regard to example 5, the origin cause of formation not always clearly still about the CHARGE DISTRIBUTION of the toner layer of coating on development sleeve 141, is not observed and has been suppressed excessive charged toner.That is to say that with regard to the adjusting number in this example and particularly with regard to example 5, the formation of not carrying out the state that electric charge applies therein fully or carrying out toner coating under the state that excessive charge applies can be considered to suppress to some extent significantly.Therefore, can apply an amount of electric charge, and can suppress the positive virtual image significantly to toner.

Therefore, with regard to regard to this example and particularly with regard to example 5, regardless of the course of developing, even but the changeable property of toner and disposability remain favourable under the situation of following state occurring, under this state because of over time or the environmental change toner of generation with excessive charge amount easily.In addition, can carry out suitable electric charge equably about toner and apply, can suppress the positive virtual image significantly thus.

On the other hand, comparative example 10 with regard to the original negative virtual image and when increasing the type face counting existing problems with regard to the positive virtual image.With regard to comparative example 10, the pressure distribution in the contact clip that development sleeve 141 and adjusting parts come in contact therein has a contact pressure maximal value.Thereby once chance is applied to toner with triboelectric charge.Therefore, it is difficult that suitable electric charge is applied to the toner with low initial charge amount, and the original negative virtual image worsens.In addition, chance that adjusting power works occurs once, and then be only once chance be used to switch toner.Therefore but disposability is bad.In addition, be used to be right after before contact clip that to suck being shaped as of toner narrow, so at the toner that is supplied to contact clip and the changeable property between the toner at contact clip place is bad.As a result, when increasing the type face counting, accumulation is applied with the toner of excessive charge on the surface of development sleeve 141.Therefore, the positive virtual image is considered to worsen.

Comparative example 12 has following configuration, and this configuration has similar to comparative example 10 two and regulates parts and be used to improve chargeable property.Therefore, but charging property improves and the original negative virtual image improves.Yet the positive virtual image is the same bad similarly with comparative example 10 when increasing the type face counting.With regard to comparative example 12,, the measurement during CHARGE DISTRIBUTION in the toner coating of development sleeve 141 can detect excessive charged toner (Figure 28) when showing.In other words, with regard to comparative example 12, translator can be increased to twice, thereby can envision, although but charging property increases the so easy toner with excessive charge amount that generates.Therefore, can envision, the easier reception of toner comes the influence of autography course, the positive virtual image therefore occurs.

Therefore, with regard to comparative example 12, do not have to obtain from development sleeve 141 with the distribute advantage that accumulates as toner in the rotation of slack V between two maximal values of the contact pressure that provided of contact clip internal pressure that parts come in contact therein is provided.Therefore, can envision, can not obtain even electric charge applies also.

In addition, become obvious among the picture appraisal result of the advantage of above-mentioned slack V from comparative example 13 in this example.That is to say, in comparative example 13, utilized rigidity to regulate parts, and the pressure distribution in the contact clip that development sleeve 141 and adjusting parts come in contact therein is set to have two contact pressure maximal values.Utilize this configuration, the original negative virtual image owing to applying property of electric charge as this example, particularly as example 5, improve and improve.Yet, no matter between two maximal values, whether there is space with weak contact pressure, the positive virtual image all appears when increasing the type face counting.Its reason may be as follows.

With regard to comparative example 13, be similar to example 5, between two maximal values, have the space of low contact pressure, thereby even but can envision charging property and also can obtain.Yet, with regard to comparative example 13, when the variation of toner quantity occurring in the space with weak contact pressure,, increase so local pressure in the space, occurs owing to utilized rigidity to regulate parts.When increasing the type face counting, the stress on the toner increases and has improved the toner degeneration significantly.As a result, can envision and generated toner, widen the CHARGE DISTRIBUTION of toner with far different quantity of electric charge.Measuring toner charge distributes and produces following observation: applied excessive charged toner or can not obtain the toner of sufficient charge.Therefore, the positive virtual image is considered to worsen when increasing the type face counting.

On the other hand, with regard to regard to this example, particularly with regard to example 5, weakened body resistance when increasing type face and count similarly is favourable.The reason of this point is considered to regard to this example compliant member is used as the adjusting parts.Therefore, with regard to regard to this example, particularly with regard to example 5, be similar to comparative example 13, toner changes the slack V place appearance between two maximal values of contact pressure.Yet, with regard to example 5, compliant member is used to regulate parts, thereby can envisions, even exert pressure partly, sheet still can be out of shape, thus the dispersion of build-up of pressure.As a result, can suppress significantly the increase of the local stress of toner and the appearance of the positive virtual image.

By comparative example 5 and comparative example 9 and 11, make development sleeve 141 with regulate the advantage that pressure distribution place in the contact clip that parts come in contact therein has a plurality of local maximums of contact pressure and become clear.

That is to say with regard to comparative example 9, small image error has been arranged for the original negative virtual image.With regard to comparative example 9, the pressure distribution in the contact clip that development sleeve 141 and adjusting parts come in contact therein has a contact pressure maximal value, and toner is once charged.Therefore, but comparative example 9 slightly is better than example 5 with regard to charging property.Therefore, there is the small negative virtual image to occur.In addition, with regard to comparative example 9, adjusting power once chance acts on toner, reduces changeable property thus.In addition, with regard to comparative example 9, between two contact pressure maximal values, there is not slack V, even electric charge applies also and can not obtain thus.Therefore, when increasing the printer paper counting the positive virtual image may appear.

With regard to comparative example 11, the pressure distribution in the contact clip that development sleeve 141 and adjusting parts come in contact therein has a contact pressure maximal value and is provided so that the folder width is wide.Therefore, the raising of applying property of electric charge has improved the original negative virtual image.Yet with regard to comparative example 11, the adjusting power of toner is identical approx with comparative example 9, and does not also have slack V, therefore changeable property and even applying property of electric charge compare with example 5 to some extent and degenerate.Therefore, the positive virtual image is considered to worsen when increasing the type face counting.

Then will by comparative example 5 and 6 and example 9 describe the position of magnetic pole of magnetic roller 142 and regulate parts about the relation between the contact position of development sleeve 141.

With regard to example 9, the peak flux density of magnetic roller 142 is positioned development sleeve 141 and regulates in the contact clip that parts come in contact therein.With regard to example 9, the original negative virtual image is favourable, but the positive virtual image worsens when increasing the printer paper counting.Reason may be as follows.

With regard to example 9, the pressure distribution in the contact clip that development sleeve 141 and adjusting parts come in contact therein has two contact pressure maximal values, occurs slack V thus.Yet when the bright density of peak value magnetic flux of magnetic roller 142 was present in the contact clip, the direction that the toner at slack V place and being not easy aims at development sleeve 41 was magnetically spurred.Therefore, be at slack V and keep stably the toner accumulation difficulty that becomes in the rotation.Thereby, the obvious stress of toner is occurred at the contact clip place, and the degeneration that improves toner easily.Therefore, the significantly positive virtual image is considered to occur when increasing the type face counting.

On the other hand, with regard to example 5 and 6, the peak flux density of magnetic roller 142 is arranged beyond contact clip.Therefore, think that so tangible toner degeneration should not occur.Therefore, the positive virtual image that can suppress when increasing the type face counting occurs.

With regard to example 6, the original negative virtual image is compared with example 5 slightly and is worsened now.The reason of this point may be that on the surperficial moving direction of development sleeve 141, the peak flux density of magnetic roller 142 is positioned the contact clip upstream recently.Particularly, when peak flux density being arranged, be supplied to the toner quantity of development sleeve 141 to become excessive in the contact clip upstream.Therefore, with regard to example 6, even applying property of electric charge and example 5 have same intensity, the quantity of electric charge that is applied to each toner still reduces.Therefore, with regard to example 6, because the minimizing of applying property of electric charge, so the original negative virtual image is considered to slightly occur.On the other hand, with regard to example 5, owing near the contact clip downstream, peak flux density is arranged, so can suppress as mentioned above excessive toner supply to development sleeve 141.In addition, with regard to example 5, the magnetic knot of toner makes a concerted effort not strengthen significantly at the regulon place, thereby the adjusting power of regulating parts does not reduce.As a result, suppressed the variation of toner coated weight, and can suppress the original negative virtual image by high applying property of electric charge.

In addition, with regard to example 5, so because the degeneration of less toner can be contemplated to, the positive virtual image is compared more favourable significantly with example 6 when increasing the type face counting.That is to say that with regard to example 5, the peak flux density of magnetic roller 142 is positioned the contact clip downstream.Now, according to the increase of type face counting, the pressure variation appears in the contact clip.Under these circumstances, the slack V between two of contact pressure maximal values may have unexpected pressure and changes in contact clip.Yet with regard to example 5, the peak value of the magnetic density of magnetic roller 142 is positioned the outlet of contact clip, i.e. contact clip downstream, and since magnetic force towards the downstream direction effect of contact clip, so toner passes control module easily.Therefore, the pressure that can suppress in the contact clip increases.That is to say, can reduce the toner stress in the contact clip, and the toner that can suppress significantly when increasing the type face counting is degenerated and positive virtual image error.

Therefore, with regard to this example, the peak flux density of magnetic roller 142 is positioned beyond the contact clip.Therefore, toner accumulates in development sleeve 141 reposefully and regulates among the slack V between two maximal values of contact pressure in the pressure distribution in the contact clip that parts come in contact therein.Thus, can realize about the raising of the applying property of electric charge of toner and even about the applying property of electric charge of toner.

In addition, with regard to this example, as in the rotation, toner being accumulated reposefully in slack V, tangible toner degeneration can be prevented, the positive virtual image when increasing the type face counting can be suppressed thus by as mentioned above.

In addition, except the peak flux density of magnetic roller 142 is positioned contact clip outside, it also is desirable peak flux density being positioned on the surperficial moving direction of development sleeve in contact clip downstream.Thus, the interior unexpected stress of contact clip can be reduced significantly, and the positive virtual image when increasing the type face counting can be suppressed significantly toner.

Then, will the chip part that be used as the soft readjustment parts and the difference between the seamless tubular shaped parts be described by comparative example 5 and example 7.Example 7 has the configuration identical with the configuration of example 5, and difference is to have utilized seamless tubular shaped parts.With regard to example 7, the positive virtual image is compared with example 5 slightly and is degenerated when increasing the type face counting.The reason of this point may be, with regard to example 7, toner is degenerated and compared easier raising with example 5, perhaps even to the applying property of electric charge of toner hangs down.That is to say, with regard to example 7, regulating parts is seamless forms, is limited thereby the bending direction that has been used as the compliant member of regulating parts at pressure under the situation that slack V place sets up and adjusting parts have that this situation of edge identical with edge in the example 5 compare.In other words, with regard to example 7, the same with example 5, even also can not obtain, be used to perhaps prevent that the advantage that local pressure increases when the toner quantity at slack V place has changed is not so good as example 5 in the applying property of electric charge that accumulation caused of slack V place toner.As a result, can envision, improve the toner degeneration, perhaps even to the applying property of electric charge of toner also reduce, occur the positive slightly virtual image thus.

Then, will by comparative example 5 and example 8 be described in the maintenance method of regulating parts with at the difference between the peaked method of the formation contact pressure of the pressure distribution in the contact clip.With regard to example 8, the positive virtual image compares with example 5 that some is bad when increasing the type face counting.The reason of this point may be that the distortion of slack V considerably is fixed in original state.That is to say, with regard to example 8,, abandon under the state that does not come in contact with development sleeve 141 and form slack V in advance in sheet compliant member place storage shape.Therefore, can obtain the advantage similar in original state to example 5.Yet, the difficulty so the dispersion of the lasting pressure of execution becomes appears brokenly because this ground pressure at slack V place is increased in when increasing the type face counting.As a result, with regard to example 8, the advantage that suppresses the positive virtual image when increasing the type face counting may some be not so good as example 5.On the other hand, with regard to example 5, form slack V by the volume that strengthens the sheet-shaped regulation parts.Can keep the distortion of slack V thus in time.As a result, can continue to carry out pressure accordingly with irregular the ground pressure increase of slack V when increasing the type face counting disperses.Thereby with regard to example 5, the toner that can suppress significantly when increasing the type face counting is degenerated and the position virtual image.

Now, when reducing device size, be accompanied by and regulate the minimizing of parts about the contact stabilization of development sleeve, toner applies state (amount of charge, toner layer thickness or the like) and becomes unstable easily.Anti-speech according to this example, as about being used for when increasing the type face counting as described in the unequal inhibition of vertical concentration machine-processed, even still keep high contact stabilization when the minimizing device size.As a result, even reduce device size, still can use in time and the stable manner inhibition virtual image.

As mentioned above, according to this example, in development sleeve 141 and the pressure distribution of regulating in the contact clip that parts come in contact therein a plurality of contact pressure maximal values are arranged, the number of times that is used for triboelectric charge is applied to toner thus increases, and about applying property of the electric charge increase of toner.Therefore, be under the state of the peanut after carton is being set at number of print pages, that is to say, even in developer reservoir 145, have under the state of a large number of toner, still the predetermined charge amount can be applied to toner with little amount of charge.Therefore, can suppress the original negative virtual image significantly.

In addition, in the pressure distribution in the contact clip that development sleeve 141 and adjusting parts come in contact therein a plurality of contact pressure maximal values are arranged, regulate the number of times increase that masterpiece is used for toner thus.Thus, but the changeable property of toner and disposability increase.Particularly, the regulon that utilizes the upstream maximal value on the surface direction be subjected to development sleeve 141 to be regulated, it is big to be used to suck being shaped as of toner, thereby improves the changeable property of the charge image developing toner of the toner supplied again from developer container 145 and reservation.The regulon that utilization is regulated by the downstream maximal value on the surface direction of development sleeve 141 can apply adjusting power under the state of regulating toner quantity in advance.Therefore, even have the surface that the toner of excessive charge quantity is bonded in development sleeve 141 by force, this still can go out of use.

In addition, by the slack V between the contact pressure maximal value of contact clip internal pressure distribution and from the peaked adjusting power in the downstream on the surperficial moving direction of development sleeve 141, can be as in the rotation, accumulating toner reposefully.Therefore, can carry out suitable electric charge more equably about toner applies.In other words, can suppress the toner that has the toner of excessive charge or have not enough electric charge significantly.

In addition, by utilizing compliant member, can prevent that this ground pressure increases when changing among the slack V of toner quantity in contact clip as regulating parts.In addition, by the magnetic pole of magnetic roller 142 being set beyond contact clip, realizing preventing significantly the toner degeneration thus, can be at slack V place as in the rotation, accumulating toner reposefully.As a result, what the toner charge that can suppress to degenerate from toner significantly distributed widens, the toner that promptly occurs having the toner of excessive charge and have not enough electric charge.Thereby, according to this example, can suppress the positive virtual image when increasing the type face counting significantly.

In addition, this ground pressure increase when suppressing the toner number change when the slack V place in contact clip significantly, the following position of magnetic pole that magnetic roller 142 is set is desirable.That is to say that it is desirable with external contact clip downstream peak flux density being set at contact clip on the surperficial moving direction of development sleeve 141.

In addition, wish that utilization has the sheet component at edge to be used as the adjusting parts.Why be that this ground pressure increase in the time of can suppressing the toner number variation when the slack V place in contact clip significantly is even perhaps applying property of electric charge also can obtain because regulating parts is not easy restrictedly on direction of twist like this.

In addition, for the irregular pressure that prevents contact clip increases, using the large volume that adds of sheet-shaped regulation parts, to form slack be more desirable.

Utilize above-mentioned advantage,, can suppress the original negative virtual image and the positive virtual image when increasing the printer paper counting significantly according to this example.That is to say, according to present embodiment, can be suppressed at initial toner charge quantity in the developer reservoir 145 and be low state down the negative virtual image and the positive virtual image when the increase printer paper is counted under the situation that excessive charge amount or toner charge distributed number broaden is appearring.Thereby, with regard to this example, can suppress the virtual image image of reflection development course in time.

Particularly, according to this example, even minimizing plant bulk and toner still can obtain above-mentioned advantage when applying state and contact condition potentially unstable.

Notice with regard to above-mentioned example, developing apparatus has been described as especially the developing apparatus of the contactless developing method of magnetic single component, this method is carried out development under the mutually non-touching state of developer bearing part and image bearing member.As mentioned above, the developing apparatus utilize the contactless developing method of magnetic single component that develops is that the present invention institute very needs, and the parts only actually of the developer bearing part that slides in the method is the adjusting parts.Yet, the present invention should be not limited thereto, and can be applied to utilize the developing apparatus of following method and be attained at the similar advantage of above-mentioned advantage thus, this method is used for developing by utilizing the magnetic single component developer and allowing developer bearing part and image bearing member to come in contact.

Regulate parts with the developer level that uses up to now and compare, according to the present invention, the adjusting parts of developer level are put forth effort on the function that improves balance when reducing device size about cost, unfavorable effect and image color inequality.

According to the present invention, can make and compare developing apparatus that size reduces with current techniques and improve assembly according to simple configuration.In addition, utilize relevant with the developer bearing part stable developer carrying amount possibility that becomes of developing that keeps for a long time.

Even the minimizing device size is regulated the still pinpoint accuracy of its assembly of needs not of parts according to developer level of the present invention.Reason may be as follows.With regard to the increase of developer bearing part the push amount relevant with developer level adjusting parts, exist as lower area, the maximal value of two contact pressures changes pro rata in this zone.Therefore, the contact pressure maximal value of expection can be set with stable manner, in assembling, not need pinpoint accuracy thus.

In addition, utilize the present invention, owing to push developer bearing part to come in contact, formed 2 contacted states of upstream one side and downstream one side relevant in developer level adjusting parts and the contact portion between the developer bearing part with the sense of rotation of developer bearing part.Therefore, promptly use simple assembly still can realize continual and steady contact condition.

In addition, owing to following reason, can be suppressed at the image color inequality on the longitudinal direction of developer bearing part after the durability test of device effectively.With regard to developer level according to the present invention is regulated parts, exist as lower area, in this zone, regulate the contact pressure maximal value that contacts between parts and the developer bearing part less than increasing about the amount of pushing of development load bearing component at developer level.Therefore, be limited in this regional scope and use, can be absorbed in the dispersion amount of pushing of regulating the relevant developer parts of parts on the whole longitudinal direction with developer level, even and after durability test, vertical concentration inequality of filled black image still can be suppressed.

Although described the present invention, will appreciate that to the invention is not restricted to disclosed exemplary embodiment with reference to exemplary embodiment.The scope of claims will be composed explanation with broad sense so that contain all remodeling, equivalent result and function.

The application has required the Japanese publication No.2006-174138 that submits on June 23rd, 2006 and the right of priority of the Japanese publication No.2006-219058 that submits on August 10th, 2006, and the full content of above-mentioned two Japanese publication is incorporated this paper by reference into.

Claims (12)

1. developing apparatus comprises:

The development load bearing component, it is configured to carry and transport developer and utilizes developer that the electrostatic image that is formed on the image bearing member is developed; And

The developer level regulating device, it is configured to regulate the amount of the developer that is transported by described developer bearing part;

Wherein, described developer level regulating device comprises:

Flexible developer level is regulated parts, and it comprises and being configured to and the contacted contact portion of described developer bearing part; And

First and second retaining parts are configured to keep described developer level to regulate parts, and contact with described developer level adjusting parts at the upstream and downstream place along the mobile direction of described developer bearing part rotation of described contact portion; And

Wherein, for the pressure distribution of described contact portion, on the direction that described developer bearing part rotation is moved, a plurality of local maximums are arranged with respect to described developer bearing part.

2. developing apparatus according to claim 1, wherein, described a plurality of local maximums are regulated the push-on force formation of parts with respect to described developer bearing part by described developer level.

3. developing apparatus according to claim 1, wherein, described developer level is regulated the parts utilization and is kept by the elastic force that at least one and described contact portion in described first and second retaining parts produce.

4. developing apparatus according to claim 1, wherein, the sidepiece that described developer level is regulated parts is applied with from least one power in described first and second retaining parts.

5. developing apparatus according to claim 1, wherein, two sidepieces that described developer level is regulated part are applied with from each the power in described first and second retaining parts.

6. developing apparatus according to claim 1, wherein, described developer level adjusting portion is divided into sheet.

7. developing apparatus according to claim 1 comprises that also the magnetic field that is arranged on described developer bearing part inside generates parts,

Wherein, described developer is the magnetic single component developer; And

For generating the magnetic fluxes Density Distribution that described magnetic field generates parts, be arranged on the direction that described developer bearing part rotation is moved beyond the described contact portion with the immediate peak flux density of described contact portion position.

8. developing apparatus according to claim 7, wherein, described peak is arranged on the downstream of described contact portion on the direction that described developer bearing part rotation is moved.

9. developing apparatus according to claim 1, wherein, described developer level is regulated parts and is had the less smooth surface in edge in described contact site office.

10. developing apparatus according to claim 1, wherein, described developing apparatus is arranged on the box that can separate from the master component of imaging device.

11. developing apparatus according to claim 1, wherein, described developing apparatus is arranged on can be in the box that described image bearing member separates from the master component of imaging device.

12. a developing apparatus comprises:

The development load bearing component, it is configured to carry and transport developer and utilizes developer that the electrostatic image that is formed on the image bearing member is developed; And

The developer level regulating device, it is configured to regulate the amount of the developer that is transported by described developer bearing part;

Wherein, described developer level regulating device comprises:

Flexible developer level is regulated parts, and it comprises and being configured to and the contacted contact portion of described developer bearing part; And

First and second support sections are configured to support two ends that described developer level is regulated parts, and

Wherein, for the pressure distribution of described contact portion, on the direction that described developer bearing part rotation is moved, a plurality of local maximums are arranged with respect to described developer bearing part.

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