CN201378253Y - Developing unit - Google Patents
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- CN201378253Y CN201378253Y CN200920050839U CN200920050839U CN201378253Y CN 201378253 Y CN201378253 Y CN 201378253Y CN 200920050839 U CN200920050839 U CN 200920050839U CN 200920050839 U CN200920050839 U CN 200920050839U CN 201378253 Y CN201378253 Y CN 201378253Y
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- carbon dust
- developer roll
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Abstract
The utility model provides a developing unit which comprises a developing roller supplying carbon powder to the surface of an electrostatic latent image carrier and a supply roller for supplying carbon powder to the developing roller, wherein the developing roller comprises an elastomer layer with surface tack and a cover layer attached to the surface of the elastomer layer. Since the cover layer of the developing roller is made of carbon powder or granular materials with the same electrical properties and mechanical properties to the carbon powder, little new electrification is generated in the surface friction of the carbon powder for developing and the developing roller; electric charge exerted on the carbon powder for developing is basically controlled by the electric field generated by the voltage exerted on the developing roller, the supply roller and a scraper; the voltage exerted on the developing roller and the supply roller can be controlled easily, so that the electrification of carbon powder particles can be performed steadily; and the electrification polar and the electrification amount of the carbon powder are almost the same, thereby obtaining steady images.
Description
Technical field
The utility model relates to a kind of developing apparatus, is applied in the image processing system of electrofax modes such as printer, duplicating machine or facsimile recorder.
Background technology
Image processing system for electrofax modes such as printer, duplicating machine or facsimile recorders has the mode of utilizing magnetic force and electrical forces in the handing-over of developer, only utilize the mode of electrical forces in addition.In the mode of utilizing magnetic force and electrical forces, utilize two-component developing agent that constitutes by magnetic carrier and non magnetic carbon dust and the monocomponent toner that only constitutes by the magnetic carbon dust.Relative with it, with in the mode of electrical forces, use the monocomponent toner that only constitutes only by non magnetic carbon dust.
Fig. 6 is illustrated in the developing apparatus in the image processing system that uses the non-magnetic mono-component developer and the formation of its periphery.These formations at first are described: form the photoconductivity insulator layer on the surface as the photosensitive drums 1 of electrostatic latent image supporting body, the photoconductivity insulator is to show electrical insulating property under normal conditions, shows the material of electric conductivity by rayed the time.Photosensitive drums 1 makes its surface charged equably toward sense of rotation 1a rotation by charging unit 2.Not shown optical system shines the surface of photosensitive drums 1 with irradiates light 10, is subjected to light-struck place on the surface of photosensitive drums 1 and has electric conductivity, and the electric charge at this place disappears, and forms electrostatic latent image on the surface of photosensitive drums 1 thus.Irradiates light 10 is undertaken by the light beam that the image that correspondence should write down changes intensity if in laser printer be.If in duplicating machine, the reflected light when irradiates light 10 is photoscanning original copy surface.From developer roll 13 supply with for the charged carbon dust of non-magnetic mono-component developer is applied on the electrostatic latent image that is formed on photosensitive drums 1 surface, make manifesting of electrostatic latent image.The lip-deep carbon dust that supplies to photosensitive drums 1 is transferred to the paper 4 that is used to write down.When transfer printing, pass through transfer member 5 from the reverse side of paper 4 and produce electrostatic attractions.Be provided with cleaning members 6 such as cleaning doctor at transfer member 5 along the downstream of sense of rotation 1a.Though this cleaning member 6 is removed and is adsorbed to photosensitive drums 1 surface but is not transferred to carbon dust on the paper 4.Transfer printing has the paper 4 of carbon dust to be transported to fixing member 7.Fixing member 7 contains warm-up mill 8 and backer roll 9, and between makes the carbon dust photographic fixing that is transferred to paper 4 by paper 4.
Developing apparatus 3 is provided with developer roll 13 in the carbon dust container 11 of its storage carbon dust 12, touch photosensitive drums 1 by the surface that makes developer roll 13, and coating carbon dust 12 is to the surface of photosensitive drums 1.Such a developing method is known as " contact " and develops.For making carbon dust container 11 interior carbon dusts 12 can be attached to the surface of developer roll 13 reliably, be provided with donor rollers 14.Apply the earth potential that connects by 17 pairs of developer rolls 13 of negative supply and be negative voltage, apply the earth potential that connects by 18 pairs of donor rollers 14 of negative supply and be negative voltage, and the negative voltage that is applied on the absolute value than the negative voltage height that is applied on the developer roll, make that to adhere to the carbon dust that is stacked into developer roll 13 surfaces charged.Also having, as cleaning member 6, can be the alternate manner beyond the scraper mode shown in the figure, as the situation with brush or roller.
The structure that uses the contact developing apparatus of non-magnetic mono-component developer and periphery thereof as mentioned above, employed developing apparatus has following problem in the prior art:
1, the expense that forms protective seam on the developer roll surface increases, and the selected of protective layer material is a technical difficult problem.Promptly mesh width owing to be necessary in developer roll and photosensitive drums at circumferential contact width between the 0.5mm to 2mm, so that the softness of developer roll elastic deformation be necessary.Therefore, the hardness of developer roll is better in the scope of 20 to 50 degree with Shore C hardness, is in this durometer level for making, and the material of developer roll generally is with NBR (nitrile rubber).What contain the plasticizer that is useful on the lower hardness of maintenance and be used to promote bridging in NBR adds the sulphur agent; but these can cause the polycarbonate crystallization for the part of photosensitive material drum; therefore in the occasion of using NBR; for preventing that these adjuvants from moving to photosensitive drums, be necessary unit protection layer on developing roller surface.But; resinous protective seam is set to developing roller surface and increased manufacturing process, and is necessary selected photosensitive drums and carbon dust are not all had the protective layer material of bad influence, still; to the selected of this class material also is a very thorny difficult problem, and these are the reasons that cause cost to raise.
2, owing to the unstable development problem of unstable of bringing of the electric charge that carbon dust is applied.Usually, carbon dust being applied electric charge is to carry out with frictional electrification with by the charged dual mode of the electric charge in electric field.Frictional electrification be carbon dust in the carbon dust container 11 by carrying out with the friction of circumferential component, so-called circumferential component be meant through with the contacting of developer roll surface, to being attached to the parts that carbon dust contacts between photosensitive drums 1 surface.By electric field apply and the charged carbon dust that is meant by between the donor rollers and developer roll that are applied in electric field, and between scraper and the developer roll and be with electric charge.In carbon dust, contain or cover the surface for make by friction with on predetermined polarity and the charged controlling agent of carried charge.At this, important thing is that the polarity of charged carbon dust wants fully consistent with predetermined polarity in carbon dust is charged, and carried charge also will remain in the predetermined scope.But though the control that applies electric charge by electric field is to be relatively easy to, also having on the other hand the development for the frictional electrification of the key element that applies electric charge is very unsettled development.Frictional electrification is subjected to pressure and the environment especially influence of humidity of above-mentioned each parts to developer roll easily, and it is difficult keeping predetermined carried charge.Also have, because the material characteristic variations on developer roll surface and the degree of adhesion of carbon dust etc., the frictional electrification amount changes, and applying stable electric charge usually is difficult more to carbon dust.The control frictional electrification is to transfer between the photosensitive drum surface from carbon dust container, takes into full account the frictional electrification sequence of the object parts of carbon dust sliding contact, is necessary to design developing apparatus integral body, and such a design is very difficult.So, in charged unsettled occasion, the carried charge skewness of each carbon powder particle, opposite extreme situations is the electric charge that has opposite polarity, can cause image quality significantly low.
3, constituting developing apparatus that reclaims the carbon dust mode or the situation of not having the developing apparatus of cleaning member mode, existence can not be kept the problem of preferable image.The manifesting of electrostatic latent image is that the image forming portion that the carbon dust by the electric charge that has normal polarity is attached to photosensitive drum surface is carried out.But, in carbon dust, there is the carbon dust of opposite polarity, the carbon dust of this opposite polarity is attached to non-image part.In ensuing transfer printing process, apply charged polarity of normal carbon dust and opposite voltage reverse side to paper, with electrostatic adhesive force transfer printing carbon dust picture to paper, but, by with the carbon dust of going up opposite polarity because identical with the polarity of the polarity of carbon dust and transfer voltage, do not produce electrostatic adhesive force, carbon dust is not transferred on the paper but remains in photosensitive drum surface.The carbon dust of opposite polarity promptly is to exist, and after transfer printing, in the mode of discarded this carbon dust, after the existing in device and start of the carbon dust of opposite polarity, need not become the obstacle of next development.But, the occasion of way of recycling, the carbon dust that remains in photosensitive drum surface is removed and is recovered to carbon dust container from photosensitive drums in next cleaning process, for recycling, along with printing repeatedly, the carbon dust of normal polarity is consumed successively, on the other side is that the carbon dust of opposite polarity is not consumed, and is recycled to carbon dust container, cause the carbon dust concentration of the opposite polarity in carbon dust container to raise, follow this and what come is to produce the development that normal image is difficult to obtain.Also have, do not establish cleaning member and reclaim carbon dust with developer roll, promptly so-called no cleaning member mode is not remove the carbon dust that remains in the opposite polarity on the photosensitive drums when transfer printing, directly transfers to next charging operation, and is charged by charging unit.At this moment, by with the carbon dust of going up the normal polarity electric charge because identical with the polarity of charging unit, no problem, but the carbon dust of the polarity opposite with normal polarity is because different with the polarity of charging unit, be attached on the charging unit, pollute charging unit, cause image quality low and image is bad.
4, in colorize with the problem of the coupling difficulty of toning system.The occasion of color mode is used multiple color (C, Y, M, K) carbon dust, and corresponding these carbon dusts of all kinds will use a plurality of developer rolls, but these carbon dusts of all kinds are separately because of the difference of coloring pigment, the charged characteristic difference, and the carried charge that is applied to carbon dust of all kinds by frictional electrification is also indefinite.Therefore, it is difficult carrying out stable colour development, with the coupling of toning system be difficult.
The utility model content
The purpose of this utility model is to provide a kind of developing apparatus that can obtain stable high quality image.
For achieving the above object, the utility model provides a kind of developing apparatus, comprising: supply with the developer roll of carbon dust to electrostatic latent image supporting body surface; Supply with the donor rollers of carbon dust to this developer roll; Wherein, described developer roll comprises elastomer layer with surface tackiness and the overlayer that adheres to this elastomer layer surface.
Utilizing the surface tackiness of elastomer layer and can be carbon dust attached to its surperficial overlayer, also can be other particulate material that has equal electrical characteristics and mechanical property with carbon dust.Generally be meant to have equal frictional electrification sequence in these said equal electrical characteristics and mechanical property, the frictional electrification sequence is when instigating two material contacts, the material of positively charged is upper, electronegative material is in the next sequence of arranging out based on principle of experience, needn't make strict regulation, with also replaceable its sequence of material that is close each other.
The overlayer that other particulate material constituted that has equal electrical characteristics and a mechanical property by carbon dust or with carbon dust is attached to its surface by the surface tackiness of elastomer layer, and this overlayer plays a part to prevent that the hardening constituent that constitutes elastomer layer from directly touching photoreceptor.Carbon dust is fed on the developer roll by the donor rollers that is located in the carbon dust container, further contacts with the tectal particulate of formation developer roll.Because the particulate material that constitutes the tectal material of developer roll and be carbon dust or have equal electrical characteristics and mechanical property with carbon dust, can produce new chargedly when carbon dust and developer roll mantle friction hardly, the electric charge that carbon dust is applied is to be controlled by the electric field that voltage produced that is applied to developer roll, donor rollers and scraper basically.Owing to can easily control the voltage that is applied to developer roll and donor rollers, the charged of carbon powder particles can stably carry out, and the charged polarity of carbon dust is also almost consistent with carried charge, can obtain stable image.
Constitute described tectal carbon dust or particle from the vividness of image be roughly spherical better.
The volume impedance that constitutes described tectal carbon dust or particle is preferably 10
6Ω cm～10
14Ω cm, the absolute value of carried charge are at 5 μ c/g～100 μ c/g, and particle diameter is at 4 μ m～25 μ m.
Such a constitute the developing apparatus that is specially adapted to reclaim the way of recycling that the carbon dust that remains in photosensitive surface utilizes again, and the developing apparatus that the no cleaning member mode of cleaning equipment need not be set between transferring member and live components.At this moment, this developing apparatus also is provided with carbon dust residual after the transfer printing is recovered to carbon dust recovering mechanism in the developing apparatus.
The developer roll that uses above-mentioned formation is in the developing apparatus of way of recycling the time, owing to can keep the normal polarity of maintenance of the most carbon dust that is recycled to carbon dust container, can be as existing apparatus, in developing repeatedly, the carbon dust concentration of the opposite polarity in the carbon dust container raises.Also have, use the occasion of the developing apparatus of color mode, though carbon dust of all kinds (C, M, Y, K) charged characteristic is different, but because on the developer roll surface that correspondence carbon dust of all kinds is set up, cover by homochromy carbon dust or with material that homochromy carbon dust has equal electrical characteristics and a mechanical property, identical with the occasion of monochrome, only just color-match can be carried out, stable colour development can be carried out with the control of electric field.
The developer roll that uses above-mentioned formation in addition is in the developing apparatus of no cleaning member mode the time, after being transferred on the paper, remain in the carbon dust that can not have opposite polarity in the carbon dust of photosensitive surface, the charged polarity of most carbon dust is unified to identical with the polarity of charging unit, therefore can not pollute charging unit.
In sum, developing apparatus of the present utility model has the beneficial effect that next coming in order are listed:
1. because the particulate material that the developer roll surface almost is equal to carbon dust or with carbon dust electrical characteristics and mechanical property covers, it is few that the carbon dust of development usefulness contacts the chance of heterogeneous thing.Therefore, the charged polarity of restriction carbon dust and the determinative of carried charge are charged direction and intensity with electric field substantially, can stablize the charged polarity and the carried charge of carbon dust, obtain highly stable image.
2. owing to can in carbon dust container, not reclaim the carbon dust of opposite polarity, can not improve the carbon dust concentration of the opposite polarity in the developing parts,, can reach preferable image yet in the occasion of the developing apparatus that is adapted to the carbon dust way of recycling.
3. since carbon dust that can residual opposite polarity to photosensitive surface, can stained charging unit, be adapted to the occasion of the developing apparatus of no cleaning member mode, also can obtain preferable image usually.
4. because the electrostatic adhesive force of developer roll and carbon dust is less, by with the contacting of the scraper of the carbon dust ulking thickness adjustment usefulness on developer roll surface, can not increase moment of torsion, less to the load of rotary driving source.
5. by carbon dust that covers the developer roll surface or the overlayer that almost has the particulate material of identical frictional electrification sequence to constitute with carbon dust; owing to can play preventing that the hardening constituent from directly touching the effect of the protective seam of photoreceptor, therefore there is no need to be provided with the costly resin system protective seam of formation.
6. in the occasion of the developing apparatus that is adapted to color mode, though the charged characteristic of carbon dust of all kinds (C, M, Y, K) is different, but owing on the developer roll surface that correspondence carbon dust of all kinds is set up being homochromy carbon dust or the particulate material covering that has equal electrical characteristics and mechanical property with homochromy carbon dust, identical with the situation of monochrome, only under the control of electric field, carry out color-match, can form stable coloured image.
Description of drawings
Fig. 1 is the developing apparatus of embodiment one of the present utility model and the structural representation of peripheral construction thereof.
Fig. 2 is the schematic cross-section of developer roll shown in Figure 1.
Fig. 3 piles up the view of carbon dust to developer roll shown in Figure 2 surface in working order down.
Fig. 4 is the partial enlarged drawing on developer roll surface shown in Figure 3.
Fig. 5 is the synoptic diagram that concerns of development compared potential and image color.
Fig. 6 is the developing apparatus of prior art and the structural representation of peripheral construction thereof.
Embodiment
Below based on accompanying drawing the utility model is elaborated.Fig. 1 illustrates developing apparatus and its peripheral construction of first embodiment of the present utility model.In developing apparatus shown in Figure 1, the parts identical with the developing apparatus of earlier figures 6 use same numbering.In the following description, be to carry out as example as developer, but developer is not limited thereto with the situation of using the non-magnetic mono-component developer.In the described developing apparatus of Fig. 6 of example explanation as a setting, be provided with the cleaning member 6 that remains in the non-magnetic mono-component developer on electrostatic latent image supporting body surface after removing transfer printing between charging unit 2 and the transfer member 5, but cleaning member be not set in the present embodiment.This mode is called no cleaning member mode (cleaner-less mode).Also have, the residual in the present embodiment carbon dust to electrostatic latent image supporting body surface is to be recovered to carbon dust container with developer roll to utilize again, and this mode is called way of recycling (recycle mode).
Referring to Fig. 1, be used to be coated with carbon dust and developer roll 33 and donor rollers 34 be installed in the carbon dust container 31 that is filled with Powdered carbon dust 12 to the developing apparatus 23 on photosensitive drums 1 surface.Carbon dust is to use the thermoplastic resin of styrene-acrylonitrile copolymer class and polyesters to cover formation, and size is about about 10 μ m.Donor rollers 34 is provided with to the surface of developer roll 33 in order to supply with carbon dust efficiently, by such setting, can successfully make carbon dust 12 transfer to developer roll 33, and can apply electric charge to carbon dust.In the present embodiment, power supply 37 applies-150V to the DC voltage of-350V to developer roll 33, power supply 38 applies-200V to the DC voltage of-600V to donor rollers 34.Be applied to donor rollers 34 polarity of voltage counter-rotating situation also can, apply in addition with the overlapping voltage condition of alternating voltage and also can.Donor rollers 34 is the spongy materials for the electric conductivity foaming body, or uses electric conductivity cylinder such as metal tube.Concrete material can be enumerated urethanes, aluminium etc.
Be provided with scraper 36 as the THICKNESS CONTROL element at the outer peripheral face of developer roll 33, its blade contact has the surface of the developer roll 33 that carbon dust adheres to, and is controlled at the carbon dust accumulating amount on developer roll 33 surfaces.This blade be relative towards in the present embodiment with the sense of rotation 33a of developer roll 33, but be not special qualification.For making on the carbon dust band between scraper 36 and the developer roll 33 predetermined electric charge, be provided with DC voltage and apply element, apply-150V to the voltage of-600V to scraper 36.Also have, scraper 36 uses conductive material to form better.Scraper 36 employed materials are better higher than the hardness of developer roll 33 employed materials.The developing apparatus of present embodiment is less because of the electrostatic adhesive force of developer roll and carbon dust, scrapes carbon dust with scraper 36 and becomes even shape, is accompanied by the contacting of carbon dust on scraper 36 and developer roll surface, and the increase of sliding torque is less, and is less to the load of rotary driving source.The above-mentioned example that is applied to developer roll, donor rollers and scraper is under the situation of electronegative carbon dust, and in the occasion of the carbon dust that uses positively charged, the voltage that applies is opposite polarity.Also have, the occasion of one of them of the carbon dust of electronegative carbon dust and positively charged all can make alternating voltage overlap onto DC voltage.
Fig. 2 is the cross-sectional illustration figure that roughly constitutes of expression developer roll 33.Developer roll 33 is conductive elastomer layers 41 that configuration is made of the hardening conductive composition around electric conductivity axis bodies 40 such as metal turning axle, also has, and is provided with the overlayer 42 that is made of carbon dust or carbon dust equivalent material on its surface.In legend, conductive elastomer layer 41 is an individual layer, still, constitutes by a plurality of conductive elastomers different on electric conductivity and hardness are folded layer by layer, and electric conductivity and the hardness of adjusting developer roll 33 integral body also can.The electric conductivity that it is emphasized that elastomer layer 41 is not to be necessary.
The carbon dust that constitutes the equal particulate material of tectal and carbon dust and be and as far as possible can frictional electrification has very approaching electrical characteristics or mechanical property, as the particulate material of selecting to be close on the frictional electrification sequence.Specifically, be that the volume impedance is 10
6Ω/cm～10
14Ω/cm, carried charge are that 5 μ c/g, particle diameter are that the particulate material of 4 μ m to 25 μ m is more suitable on absolute value.Also have, this particulate material is also identical with carbon powder for development, that is to say, main material is styrene-acrylonitrile copolymer class or polyester resin, for the carbon black of colorant and impedance Control agent, for the silicon of inorganic additive, be that the material of charged controlling agent is better.With these is that main material is made the carbon dust roughly spherical in shape of 5 μ m to 10 μ m because the high advantage of vividness of image is arranged by polymerization, thereby especially good.
By carbon dust or with tectal bed thickness that the equal particulate material of carbon dust constitutes be better thin basically, still, from developer to adhere to the viewpoint that forms with electric field better at 4 μ m to 50 μ m.Tectal formation method is not done special qualification, and can make developing roller surface is that the method for smooth flat is better.As being undertaken by sprinkling, immersion, roller coat, brushing etc.Especially use situation with the carbon dust identical materials as tectal particulate material, under the state that the conductive elastomer layer with surface tackiness exposes, rotation number time in carbon dust container also can by carbon dust in the carbon dust container is adhered to.
Also have, as shown in Figure 3 and Figure 4, the layer thickness d of the carbon powder for development T that is regulated by scraper 36 is from keeping the charged inhomogeneity viewpoint of carbon dust, the mean grain size of development carbon powder particles below 3 times better.Surpass 3 times, can cause not charged carbon dust to increase or the charged skewness of carbon dust, also have with the field that the contacts electric field of photoreceptor a little less than, the result causes producing developing fog and carbon dust and the non-constant of image quality such as flies away.
Tectal material is by using carbon dust or with carbon dust the particle of equal electrical characteristics and mechanical property being arranged, the material that specifically has equal frictional electrification sequence by use, the carbon dust that contacts with the developer roll surface hardly can be with going up new electric charge, the charged polarity of carbon dust and carried charge mainly are direction and the intensity by the electric field in the immediate zone that is applied to donor rollers and developer roll, and by scraper be applied to the carbon dust thin layer form the zone direction of an electric field and intensity control.The control of these electric fields is easy, so that the electriferous state of carbon dust becomes is stable.This developing apparatus is compared with existing developing apparatus, and the heterogeneity of the charged characteristic of carbon dust lacking very, therefore the producing to Min. of carbon dust that can suppress opposite polarity in addition can keep highly stable image.
The developing apparatus of present embodiment is owing to be the developing apparatus of no cleaning member mode, be not removed at the carbon dust that remains in after the transfer printing on the photosensitive drums, in aforesaid developing apparatus, can carry out the charged control of carbon dust well where by charging unit, the charged polarity of residual carbon dust on photosensitive drums after the transfer printing by unified to the polarity same polarity of charging unit 2, the carbon dust of opposite polarity (positively charged) does not exist or seldom exists, and residual carbon dust to photosensitive drum surface can not pollute charging unit.In the developing apparatus of no cleaning member mode, the pollution of charging unit all is considered problem all the time, what particularly the generation of ozone brought is unfavorable, so in the way of contact of using the roll-type utilized by expectation or brush charging unit, it is most penetrating problems that carbon dust is attached to these charging units, can solve and eliminate these problems by the utility model device.Also have in the device of present embodiment, carbon dust recovering mechanism by formations such as developer rolls is recovered in after the transfer printing residual carbon dust to photosensitive drum surface in carbon dust container, the carbon dust of opposite polarity does not have or seldom in the carbon dust that is recovered, in development repeatedly as the prior art, the carbon dust concentration of the opposite polarity in the carbon dust container can not raise, and does not worry the deterioration of image.
Integral resinous protective seam in the prior art; to developer roll of the present utility model is unnecessary; can reduce cost; and there is no need the selected material that satisfies the protective seam that characteristic such as frictional electrification requires; need only pay attention to the selected of developer roll material, as electrical characteristics such as the hardness of roller, roller impedances.
Fig. 5 illustrates the relation of development compared potential and the final image color ID that forms on the paper 4 that is used to write down, solid line is represented present embodiment, and double dot dash line is represented to be provided with and prevented that photosensitive drums from polluting the example of used resin protective layer to the prior art on developer roll surface.In the present embodiment, only adhere to 1 to 3 layer carbon dust layer on the surface of developer roll 33, the distance between photoreceptor and the developer roll is very approaching, and in view of the above, the electric field of generation is eager to excel than the electric field of the visualization way of prior art.Also have, the carbon dust of development usefulness is owing to the carbon powder material with the developer roll surface has the electrostatic adhesive force on same nature and developer roll surface little on electrical characteristics.Therefore, among the result with the present embodiment shown in the solid line, even if development compared potential (the exposure current potential on development bias voltage and the photosensitive drums poor) is less, still can obtain high image density ID, also have, to obtain Cmax on the developer roll surface, generalized case is ID=1.4, need only exist by necessary carbon dust, even if be in very high state the development compared potential, also need not adhere to and surpass necessary carbon dust, can obtain stable concentration usually.By comparison, have resin system protective seam in the non-magnetic mono-component visualization way of prior art, and reach about 5 layers adhering to of carbon powder particles, the electric field that produces between photosensitive drums and developer roll is little.Also have owing to carbon dust and its superficial layer frictional electrification, superficial layer is by the electric charge with last and carbon dust opposite polarity, and both electrostatic attractions are bigger.Therefore, obtain predetermined image concentration (carbon dust adhesion amount), high development compared potential is necessary.Also have, in the visualization way of prior art, on developer roll, obtain maximum image concentration, adhere to the above carbon dust of carbon dust necessary amount, in the very high zone of development compared potential, necessary above carbon dust amount is attached to photosensitive surface, becomes the reason of infringement image quality.That is to say,, also adhere to the above carbon dust of necessary adhesion amount though image color is saturated.This state is represented with the double dot dash line among the figure.Promptly shown in the double dot dash line in using figure, show and follow the development compared potential to rise, image color gently rises, and is issued to Cmax at predetermined potential, and the carbon dust adhesion amount is in the phenomenon that obtains also can continuing to increase more than the development compared potential of Cmax.It is the carbon dust of not wanting fully that this image color reaches the carbon dust that Cmax also continues to increase, and becomes the principal element that hinders the image that forms high-quality.Especially, in no cleaning member mode, carbon dust is attached to and surpasses necessary amount on the photoreceptor, in the transfer printing stroke, whole carbon dusts on the transfer printing photoreceptor are difficult to transfer paper, produce the residual phenomenon to photoreceptor of carbon dust, become the reason of the image quality of infringement in next stroke.Also have in existing visualization way; protective seam as developer roll has by the easy electronegative characteristic of frictional electrification, and under such situation, the carbon dust sliding contact is to its surface; promptly be to be that the part in the carbon dust is positively charged but under the material situation of electronegative property at carbon dust.If such a carbon dust exists, enter the static printing stroke that makes the electric field that produces predetermined polarity, so that be transferred on the paper with electrostatic attraction, but the carbon dust of the positively charged on the photoreceptor can not be transferred on the paper, but residual to photoreceptor, in no cleaning member mode, pollute the charging unit of next stroke, perhaps be recycled in the carbon dust container, cause the concentration of the positively charged carbon dust in carbon dust container to rise, the quality of entire system reduces.In such a existing developing apparatus, because the charged inhomogeneous various obstacles that cause, because in developing apparatus of the present utility model, can prevent inhomogeneous chargedly as much as possible, therefore can not produce such obstacle.
More than, about independent cleaning member (no cleaning member mode) and the narration of the mode of the carbon dust of utilization recovery more are not set as embodiment,, also is to be suitable for certainly even if the utility model does not adopt a side or the both sides of these modes.
Be the explanation of hardening conductive composition that constitutes the conductive elastomer layer of developer roll at last.The condensate that the hardening conductive composition is made of the polyoxyalkylene that has an alkenyl in the molecule at least (A); (B) in molecule, contain the compound of plural hydrosilyl groups; (C) catalyzer of hydrosilylation; (D) electric conductivity gives the material formation.Concrete example as the hardening conductive composition, for example, enumerate and in molecule, have an alkenyl at least, the recurring unit that constitutes main chain is the condensate for oxyalkylene nuit, constitute (A) composition, in molecule, contain plural hydrosilyl groups for (B) composition of rigidizer, for (C) composition of the catalyzer of hydrosilylation, for electric conductivity gives (D) composition of agent, contain that the hardening conductive composition of above (A), (B), (C), (D) each composition constitutes layer example.Certainly, also have the layer that is made of other constituent below the layer that is made of the hardening conductive composition, for example, it is also better to be provided with the layer that is made of polycarbamate, polysiloxane, NBR (nitrile rubber), EPDM (ethylene-propylene-diene rubber) etc.Certainly be also can in the outside of whole turning axle by the layer that the hardening conductive composition forms.In this case, obtain having soft, low compression deformation set, the conducting rubber of feature such as outflow seldom.
Below will describe the hardening conductive composition of the elastomer layer that constitutes developer roll in detail.(A) composition in the hardening conductive composition and the reaction of (B) composition and the sclerosis that are rigidizer are the compositions that constitutes the hardening thing of caoutchouc elasticity.
The recurring unit that constitutes the main chain of (A) composition is an oxyalkylene nuit, main chain is as initial substance, be to have plural compound bearing active hydrogen,, make by making the epoxyalkane polymerization as spent glycol, bisphenol compound, glycerine, trimethylolpropane, season pentanediol etc.Constitute according to the polymeric object lesson of manufactured like this main chain can enumerate in polyoxyethylene, polypropyleneoxide, polyoxybutylene, ethylene oxide, epoxypropane and the butylene oxide two or more arbitrarily or segmented copolymer etc., alkenyl is directed to end thereby has the characteristics of caoutchouc elasticity better.In above-mentioned molecule, has an alkenyl at least, the recurring unit that constitutes main chain is the condensate for oxyalkylene nuit, as object lesson preferably, viewpoint from the softization of hardening thing, the recurring unit of main chain is that propylene oxide unit is better, in necessary spongy occasion, a part that changes propylene oxide unit is that the copolymer of ethylene oxide is better.
Contain (A) composition alkenyl number since with (B) composition reaction, at least more than one, better at 2 to 6.
(A) molecular weight of composition is from the balance of reactive and softization, and number mean molecular weight (Mn) is between 500 to 50000, and is particularly better between 1000 to 20000, has alkenyl in molecular end, has the characteristics of softization better.
Following (B) composition in the hardening conductive composition, the rigidizer that has two hydrosilyl groups in molecule at least is described (A) composition.The recurring unit that is formed in the main chain that has an alkenyl in the molecule at least is the condensate for oxyalkylene nuit, is the composition that plays the rigidizer effect.
This (B) composition better is at 2 to 50 owing to contain 2 hydrosilyl groups at least in molecule, is more preferably 2 to 30, further at 2 to 20, alkenyl reaction in 3 to 12 hydrosilyl groups preferably, each hydrosilyl groups and the molecule that exists in (A) composition, sclerosis.The number of the hydrosilyl groups in described (B) composition is less than 2, makes in hydrosilylation reactions under the situation of sclerosis of hardening conductive composition, and setting rate is slower, and it is more that the sclerosis condition of poor takes place.Also have, the number of this hydrosilyl groups exceeds 50, is the stability of the rigidizer of (B) composition, and then the bad stability of hardening conductive composition, and the sclerosis back is remaining a large amount of hydrosilyl groups easily becomes useless and reason fracture easily.
Above-mentioned situation, it promptly is that a SiH is arranged that a hydrosilyl groups is arranged, and in the occasion of SiH2 two hydrosilyl groups is arranged, better in the hardening in conjunction with the hydrogen of different silicon with the hydrogen of silicon combination, sees also better in addition from caoutchouc elasticity.
(B) molecular weight of composition is from aspects such as the dispersiveness of (D) described later composition and roller processabilities, number mean molecular weight (Mn) 30000 below better, further preferable below 20000, particularly below 15000 better.Consideration and (A) reactivity and the intermiscibility of composition again, best 300 to 10000.
To the not special qualification of do of (B) composition as the aforementioned, as using polysiloxane-based rigidizer preferably.
In the aforementioned various hydrosilyl groups, the rigidizer that contains the nytron system for the hydrosilyl groups of (C) composition be from worrying to damage the intermiscibility with other organic polymer body, and the molecular weight of part that constitutes hydrosilyl groups is better 500 below.
In the hardening conductive composition,, use hydrosilylation catalysts into (C) composition with aforementioned (A) composition, (B) composition while.To being the not special restriction of do of hydrosilylation catalysts of this (C) composition, as object lesson, as supporting body load bearing solid platinum by platinum, aluminium and silicon, carbon black etc., complex compounds such as chlorination platinic acid, chlorination platinic acid and ethanol, acetaldehyde, ketone, platinum/alkene complex, platinum/phosphite complex compound etc. are better.
Also have, the electric conductivity that contains promising (D) composition in the hardening conductive composition gives material.Electric conductivity as this (D) composition gives material, can enumerate carbon black, the lemel end, have the 4th grade of ammonium salt base in addition, the carvol acidic group, sulfonic group, sulfate group, the organic compound of phosphate-based grade or condensate, ether-ether acid amides (ether ester amide) or ether imines (etherimide) condensate, ethylene oxide-epoxyhalopropane (ethylene oxide-epihalohydrin) copolymer, polyethylene glycol acrylates (methoxypolyethelene glycol acrylate) that contains methoxyl etc. typically has the compound of conductive unit, and perhaps charged preventor such as macromolecular compound etc. gives the example of the compound etc. of electric conductivity.Electric conductivity as (D) composition gives agent, does not mind with multiple.
Aforementioned hardening conductive composition is to be modulated by (A) to (D) composition.Such a hardening conductive composition is when forming conductive elastic layer 2, form the viewpoint of good engagement width from scraper and with photoreceptor, in JISA (Japanese Industrial Standards) hardness below 40 °, better be below 25 °, (A) composition and (B) usage ratio of composition be per 1 mole alkenyl in (A) composition, (B) hydrosilyl groups of composition better is 0.4 mole to 2.5 moles a usage ratio at 0.2 mole to 2.5 moles.The use amount of also promising (C) composition hydrosilylation catalysts is used the scope of 10-1 to 10-6 mole for 1 mole of alkenyl in (A) composition.Also have, the use amount that gives agent for the electric conductivity of (D) composition is 100 parts (parts by weight, below identical) for the total amount of (A) to (C) composition, use at 0.1 to 50 part, and better be 0.3 to 30 part, the volume impedance of conductive elastic layer is 10
3To 10
10Ω cm, more fortunately 10
5To 10
8Ω cm.In aforementioned hardening conductive composition, if be necessary, add non-conductive fillers such as silicon, magnesium carbonate, age resisters etc. are better.The amount that adds is 100 parts for the total amount of (A) to (D) composition usually, adds below 50 parts, and better be below 20 parts, never improve rubber hardness, be preferably.
Claims (5)
1. developing apparatus comprises:
Supply with the developer roll of carbon dust to electrostatic latent image supporting body surface;
Supply with the donor rollers of carbon dust to this developer roll;
It is characterized in that:
Described developer roll comprises the elastomer layer with surface tackiness and adheres to the overlayer on this elastomer layer surface.
2. developing apparatus according to claim 1 is characterized in that: described overlayer is made of carbon dust.
3. developing apparatus according to claim 2 is characterized in that: constitute described tectal carbon dust and be spherical.
4. developing apparatus according to claim 2 is characterized in that: the volume impedance that constitutes described tectal carbon dust is 10
6Ω/cm～10
14Ω/cm, the absolute value of carried charge are 5 μ c/g～100 μ c/g, and particle diameter is 4 μ m～25 μ m.
5. developing apparatus according to claim 2 is characterized in that: this developing apparatus also is provided with carbon dust residual after the transfer printing is recovered to carbon dust recovering mechanism in the developing apparatus.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200920050839U CN201378253Y (en) | 2009-01-20 | 2009-01-20 | Developing unit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200920050839U CN201378253Y (en) | 2009-01-20 | 2009-01-20 | Developing unit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201378253Y true CN201378253Y (en) | 2010-01-06 |
Family
ID=41518370
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN200920050839U Expired - Fee Related CN201378253Y (en) | 2009-01-20 | 2009-01-20 | Developing unit |
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| Country | Link |
|---|---|
| CN (1) | CN201378253Y (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101893836A (en) * | 2010-04-01 | 2010-11-24 | 珠海天威飞马打印耗材有限公司 | Processing box |
-
2009
- 2009-01-20 CN CN200920050839U patent/CN201378253Y/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101893836A (en) * | 2010-04-01 | 2010-11-24 | 珠海天威飞马打印耗材有限公司 | Processing box |
| CN101893836B (en) * | 2010-04-01 | 2011-11-16 | 珠海天威飞马打印耗材有限公司 | Processing box |
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