CN101246341A - Image forming apparatus and image forming method - Google Patents

Image forming apparatus and image forming method Download PDF

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Publication number
CN101246341A
CN101246341A CNA2008100062360A CN200810006236A CN101246341A CN 101246341 A CN101246341 A CN 101246341A CN A2008100062360 A CNA2008100062360 A CN A2008100062360A CN 200810006236 A CN200810006236 A CN 200810006236A CN 101246341 A CN101246341 A CN 101246341A
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China
Prior art keywords
toner
supporting body
roller
component developer
image
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CNA2008100062360A
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Chinese (zh)
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CN101246341B (en
Inventor
藤岛正之
渡边昭宏
上村纱代
森幸广
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Kyocera Document Solutions Inc
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Kyocera Mita Corp
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Priority claimed from JP2007044408A external-priority patent/JP5134829B2/en
Priority claimed from JP2007067545A external-priority patent/JP5001689B2/en
Application filed by Kyocera Mita Corp filed Critical Kyocera Mita Corp
Publication of CN101246341A publication Critical patent/CN101246341A/en
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  • Dry Development In Electrophotography (AREA)
  • Magnetic Brush Developing In Electrophotography (AREA)
  • Developing For Electrophotography (AREA)
  • Control Or Security For Electrophotography (AREA)

Abstract

The invention provides an image forming apparatus having a touchdown-development type developing apparatus, in which a toner collecting roller that collects scattered toner suspended in the vicinity of a toner holding body and a two-component developer holding body is arranged on the downstream side in a rotational direction of the two-component developer holding body from a closest position of the two-component developer holding body and the toner holding body, and between the two-component developer holding body and the housing wall, and further, bias means that applies a bias voltage for collecting the scattered toner to the toner collecting roller, and image density sensing means for sensing a density of a toner image developed on the electrostatic latent image holding body surface or a toner image on a transfer body onto which the toner image developed on the electrostatic latent image holding body surface is transferred to control the bias voltage are provided.

Description

Image processing system and image forming method
Technical field
The present invention relates to utilize duplicating machine, printer, facsimile recorder and their image processing systems such as compounding machine of electrofax mode, being particularly related to use makes the charged two-component developer of nonmagnetic toner form magnetic brush with magnetic carrier, on developer roll, form toner thin layer by magnetic brush, the toner of toner thin layer is leaped to electrostatic latent image, make the image processing system of this image development thus.
Background technology
In the past, in the image processing system of electrofax mode, known a composition visualization way and binary visualization way arranged as the visualization way of using dry toner.
In a composition visualization way, owing to do not contain carrier, therefore can not cause the electrostatic latent image disorder of photoreceptor owing to the magnetic brush that forms by carrier and toner, therefore be suitable for high image qualityization.But, in a composition visualization way, be difficult to stably keep the carried charge of toner.In addition, when using color toner,, therefore need to use nonmagnetic toner owing to require permeability.Therefore, form in the device, in most of the cases adopt and use carrier to be used as making the binary visualization way that toner is charged and transport the medium of toner at full-colour image.
As the image forming method that uses the binary visualization way, known have based on what is called landing (touchdown) the development image forming method of (being also referred to as mixing (hibrid) develops), described landing is developed and is meant: by the magnetic brush that forms on the developer carrier of carrying two-component developer, on toner carrier, form toner thin layer, make latent electrostatic image developing on the electrostatic latent image supporting body and visual by the toner thin layer on the toner carrier.But, this visualization way is combined a binary visualization way and a composition visualization way, the different problem of suitable carried charge of the toner of the suitable carried charge that has a toner when making latent electrostatic image developing during with the formation toner thin layer, it is bad to cause that owing to the toning dosage of toner thin layer is few image color takes place sometimes, perhaps causes taking place development ghost image problems such as (ghost) owing to stripping of the toner thin layer that is not used to develop is bad.
Therefore, for example in patent documentation 1 (the Japanese documentation spy opens the 2003-280357 communique), provide following means: to developer roll apply the direct current biasing that superposeed, dutycycle is 10～50% AC bias, suppress the development ghost image, select development.But as mentioned above, because thin layer is different with the only toner carried charge in when development when forming, so the countermeasure of taking by described means is also insufficient sometimes.
On the other hand, as one of reason that produces the problems referred to above, can list the influence of the toner that disperses.Near dispersing etc. dispersing when the dispersing of toner is included in agitation of toner in the housing, the magnetic roller, developing apparatus is main generation place.And, the toner that disperses that produces in developing apparatus can disperse to the inside of the electrophotograph apparatus that disposes electrostatic latent image supporting body, optical system device, Charging system, transfer device etc., causes that the various images that comprise the problems referred to above are bad, action is bad etc.
In order to address this problem, proposed following technical scheme in patent documentation 2 (the Japanese documentation spy opens flat 8-137256 communique): using disperses prevents from parts and scrapes the unit to prevent that toner from dispersing, described disperse prevent parts with the spaced apart and on the other side state of electrostatic latent image supporting body under be arranged to and can rotate freely, the developer that disperses when making supply developer adheres to from the teeth outwards, prevent that it from dispersing to the outside, the described unit that scrapes scrapes attached to described dispersing and prevents developer on the parts.
In patent documentation 3 (the Japanese documentation spy opens the 2005-242194 communique), following mode has been proposed: in the binary visualization way, the recovery roller is set in the shell nozzle portion of developing apparatus reclaims the toner that disperses, strip toner and it is turned back to the developing apparatus from this recovery roller.
In patent documentation 4 (the Japanese documentation spy opens flat 11-174792 communique), following means have been proposed: have the control module that changes the biasing that imposes on described recovery roller according to the image rate that is formed, this control module is lower than in image rate makes the biasing that the alternating voltage DC voltage stack identical with the regular charged polarity of developer with polarity forms that is biased to that imposes on described recovery roller under 5% the situation, be that to make described biasing under 5～15% the situation only be the alternation biasing in image rate, under more than or equal to 15% situation, make the described biasing that is biased to the regular charged opposite polarity DC voltage stack formation of alternating voltage and polarity and developer.
But,,, can only reclaim the toner of fixed amount all the time therefore by the method for patent documentation 2 because the toner amount of dispersing changes according to the toner replenishing amount.Particularly in the landing visualization way, the toner that disperses can impact the toner thin layer on the developer roll, and the image disorder takes place sometimes, therefore more needs to suppress toner and disperses.
In addition, in the landing visualization way, the toner concentration height of two-component developer, the flowability of developer is poor, therefore when magnetic brush being recovered in the two-component developer accommodation section, owing to can continuously reclaim developer, so developer can be filled in, be compressed, lose the place that holds air simultaneously, air can be released to the outside with toner, disperses thereby be more prone to take place toner.
And, in the landing visualization way,, then on the sleeve of developer roll, toner can residually be arranged if the image rate that is formed is low, therefore the method by patent documentation 2 can make the toner on the developer roll charged on the contrary sometimes, and the toner amount of dispersing also can increase in addition.
In the landing visualization way, under the low situation of printing rate (image rate), for example be lower than under 5% the situation, the not charge image developing toner that remains on the developer roll is many, this not charge image developing toner be recovered by carrying two-component developer on the left magnetic roller, that comprise carrier and toner at least, the two-component developer on the magnetic roller is recycled in the two-component developer accommodation section in the developing apparatus.Therefore, because the amount of the toner that is recovered is many, so the amount of the toner in the two-component developer that is recovered is also many, therefore toner takes place when the two-component developer on the magnetic roller is recycled in the two-component developer accommodation section easily disperse.
In patent documentation 3, it is turned back under the situation the developing apparatus, need to be provided with in addition the path that toner is returned, therefore exist device to become big disadvantage.
In patent documentation 4, disperse even also can't suppress toner when adopting above-mentioned constituting.Be in the high speed machine more than the 180mm/sec adopting landing visualization way and photosensitive drums linear velocity particularly, toner takes place and disperses in some series that has increased the developer total amount in order to suppress developer degradation easily.By the way,, when the linear velocity of photosensitive drums is 180mm/sec, under the situation horizontal, be approximately 40/minute, when for 250mm/sec, be approximately 50/minute, when for 340mm/sec, be approximately 60/minute for A4 as benchmark.
In addition, in the landing visualization way, known have for stable from the toner carrier to the photosensitive drums development and make the stable means of thickness of the toner layer on the toner carrier.These means are as follows: change by making the potential difference (PD) Δ V between toner carrier and the two-component developer supporting body, the charged characteristic of the toner that compensation changes owing to the deterioration of two-component developer etc. stably keeps the thickness of the toner thin layer on the toner carrier.But, this is the control that potential difference (PD) Δ V is changed according to the toner carried charge in the two-component developer, under the low situation of toner carried charge, toner layer meeting thickening on the toner carrier, in order to make the toner layer on the toner carrier is original thickness, needs to reduce potential difference (PD) Δ V.Because this is to be difficult to change to the direction that toner carrier moves from the magnetic brush that left magnetic roller forms to toner, therefore be recycled in the two-component developer recoverer under the residual situation that the toner that much is not used to form toner thin layer arranged in the magnetic brush on can left magnetic roller, become the state that easy generation toner disperses.That is, potential difference (PD) Δ V is because the difference of toner carried charge and difference, and the toning dosage that disperses can be because the difference of this potential difference (PD) Δ V and difference, so under the constant situation of the recovery power that makes the recovery roller, existence can't suppress the problem that toner disperses.
Summary of the invention
Problem of the present invention is to provide a kind of and can suppresses toner in landing in the visualization way and disperse, particularly can suppress the generation of the toner that disperses that the difference of the difference of difference, printing rate owing to the toner carried charge or toner replenishing amount causes, thereby can in long-term, keep stable developing property, obtain the image processing system and the image forming method of stable image.
The 1st image processing system of the present invention and the image forming method that are used to address the above problem have following formation.
(1) the 1st image processing system comprises in housing at least: the two-component developer supporting body at the internal configurations parts that are magnetic, keeps comprising the developer of carrier and toner by magnetic; And toner carrier, transfer toner from described two-component developer supporting body to self, carry toner thin layer from the teeth outwards; Apply developing bias to described toner carrier and/or described two-component developer supporting body, make the latent electrostatic image developing that on electrostatic latent image supporting body surface, forms, described image processing system is characterised in that, compare with the approximated position of described two-component developer supporting body and described toner carrier, the toner that near the toner that disperses that is suspended in described toner carrier and the described two-component developer supporting body is reclaimed reclaims downstream one side that roller is configured in the sense of rotation of described two-component developer supporting body, and be configured between the wall of described two-component developer supporting body and described housing, and, described image processing system comprises: bias unit, reclaim roller to described toner and apply and be used to reclaim the bias voltage of toner of dispersing; The image color detecting unit, to toner picture that is developed on the described electrostatic latent image supporting body surface or transfer printing the concentration of the toner picture on the transfer article of the toner picture that is developed on the described electrostatic latent image supporting body surface detect; And control module, use the testing result that obtains by described image color detecting unit control by described bias unit to described toner reclaim that roller applies, be used to reclaim the bias voltage of toner of dispersing.
(2) described image processing system can have following formation, promptly, also comprise the bias difference setup unit of setting the bias difference Δ V between described two-component developer supporting body and the described toner carrier according to the toner concentration that is detected by described image color detecting unit, described control module is controlled the described bias voltage that applies to described toner recovery roller according to the bias difference Δ V of described setting.
(3) described image processing system can have following formation, promptly, control module carries out following control: be higher than at described toner concentration under the situation of normal concentration, after making described bias difference Δ V change, form the image patch once more and detect the concentration of this image patch, repeat said process and until becoming described normal concentration by described image color detecting unit.
(4) described image processing system can have following formation,, under the situation of the described bias difference Δ V when becoming described normal concentration less than the threshold value of regulation, increases the described bias voltage that imposes on described toner recovery roller that is.
(5) described image processing system can have following formation, that is, also comprise: the surface potential detecting unit, detect the surface potential of described toner carrier; And toner carried charge computing unit, according to the surface potential of the described toner carrier that detects by described surface potential detecting unit and the toner concentration that detects by described image color detecting unit, calculate the toner carried charge of the toner thin layer on the described toner carrier; Described control module is controlled according to this result of calculation and is imposed on the described bias voltage that described toner reclaims roller.
(6) described image processing system can have following formation, that is, the peripheral speed of described electrostatic latent image supporting body is more than or equal to 180mm/sec.
(7) the 1st image forming methods use two-component developer supporting body and the toner carrier that is arranged in the housing, apply developing bias to described toner carrier and/or described two-component developer supporting body, make the latent electrostatic image developing that on electrostatic latent image supporting body surface, forms, described two-component developer supporting body is at the internal configurations parts that are magnetic, the developer that keeps comprising carrier and toner by magnetic, described toner carrier is transferred toner from described two-component developer supporting body to self, carry toner thin layer from the teeth outwards, described image forming method is characterised in that, the testing result that use obtains by the image color detecting unit is controlled and is reclaimed to toner by bias unit that roller applies, be used to reclaim the bias voltage of toner of dispersing, described image color detecting unit be used for to toner picture that is developed on the described electrostatic latent image supporting body surface or transfer printing the concentration of the toner picture on the transfer article of the toner picture that is developed on the described electrostatic latent image supporting body surface detect, compare with the approximated position of described two-component developer supporting body and described toner carrier, the described toner that near the toner that disperses that is suspended in described toner carrier and the described two-component developer supporting body is reclaimed reclaims roller and is configured in downstream one side of the sense of rotation of described two-component developer supporting body, and is configured between the wall of described two-component developer supporting body and described housing.
(8) described image forming method can have following formation, promptly, according to the toner concentration that detects by described image color detecting unit, set bias difference Δ V between described two-component developer supporting body and the described toner carrier for the thickness with the toner thin layer on the described toner carrier is maintained constant substantially, control to described toner according to the bias difference Δ V of described setting and reclaim the described bias voltage that roller applies.
(9) described image forming method can have following formation, promptly, be higher than at described toner concentration under the situation of normal concentration, after making described bias difference Δ V change, form the image patch once more and detect the concentration of this image patch, repeat said process and until becoming described normal concentration by described image color detecting unit.
(10) described image forming method can have following formation,, under the situation of the described bias difference Δ V when becoming described normal concentration less than the threshold value of regulation, increases the described bias voltage that imposes on described toner recovery roller that is.
(11) described image forming method can have following formation, promptly, according to the surface potential of the described toner carrier that detects by the surface potential detecting unit and the toner concentration that detects by described image color detecting unit, calculate the toner carried charge of the toner thin layer on the described toner carrier, control the described bias voltage that imposes on described toner recovery roller according to this result of calculation, wherein, described surface potential detecting unit detects the surface potential of the described toner carrier that is used to control described bias voltage.
According to described the 1st image processing system and image forming method, compare with the approximated position of two-component developer supporting body and toner carrier, toner reclaims downstream one side that roller is configured in the sense of rotation of described two-component developer supporting body, and be configured between the wall of described two-component developer supporting body and described housing, therefore can make the toner that disperses reclaim to catch on the roller and collect and reclaim attached to described toner.And, described toner reclaims roller and comprises applying and be used to reclaim the bias unit of bias voltage of toner of dispersing, by this bias unit, according to controlling described bias voltage with the relevant toner carried charge of toning dosage that disperses, therefore can be further the toner bed thickness control on the peculiar toner carrier and the different toners that disperses is recovered on the described toner recovery roller with generating capacity effectively because landing is developed.As a result, can suppress toner and disperse, obtain picture quality steady in a long-term.
The 2nd image processing system of the present invention and image forming method have following formation.
(12) the 2nd image processing systems comprise in housing at least: the two-component developer supporting body at the internal configurations parts that are magnetic, keeps comprising the developer of carrier and toner by magnetic; And toner carrier, transfer toner from described two-component developer supporting body to self, carry toner thin layer from the teeth outwards; Apply developing bias to described toner carrier and/or described two-component developer supporting body, make the latent electrostatic image developing that on electrostatic latent image supporting body surface, forms, described image processing system is characterised in that, compare with the approximated position of described two-component developer supporting body and described toner carrier, the toner that near the toner that disperses that is suspended in described toner carrier and the described two-component developer supporting body is reclaimed reclaims downstream one side that roller is configured in the sense of rotation of described two-component developer supporting body, and be configured between the wall of described two-component developer supporting body and described housing, and, described image processing system comprises: bias unit, reclaim roller to described toner and apply and be used to reclaim the bias voltage of toner of dispersing; And control module, carry out following control, promptly, threshold amplitude to printing rate and regulation compares, under the situation of described printing rate, reclaim roller to described toner and apply the bias voltage that the alternating voltage DC voltage stack identical with the regular charged characteristic of developer with polarity forms greater than the higher limit of described threshold amplitude; Be positioned in described printing rate under the situation of scope of described threshold amplitude, reclaim roller to described toner and only apply alternating voltage; Under the situation of described printing rate, reclaim roller to described toner and apply the bias voltage that the alternating voltage DC voltage stack opposite with the regular charged characteristic of developer with polarity forms less than the lower limit of described threshold amplitude.
(13) described image processing system can have following formation, that is, the peripheral speed of described electrostatic latent image supporting body is more than or equal to 180mm/sec.
(14) the 2nd image forming methods use two-component developer supporting body and the toner carrier that is arranged in the housing, apply developing bias to described toner carrier and/or described two-component developer supporting body, make the latent electrostatic image developing that on electrostatic latent image supporting body surface, forms, described two-component developer supporting body is at the internal configurations parts that are magnetic, the developer that keeps comprising carrier and toner by magnetic, described toner carrier is transferred toner from described two-component developer supporting body to self, carry toner thin layer from the teeth outwards, described image processing system is characterised in that, threshold amplitude to printing rate and regulation compares, under the situation of described printing rate, reclaim roller to described toner and apply the bias voltage that the alternating voltage DC voltage stack identical with the regular charged characteristic of developer with polarity forms greater than the higher limit of described threshold amplitude; Be positioned in described printing rate under the situation of scope of described threshold amplitude, reclaim roller to described toner and only apply alternating voltage; Under the situation of described printing rate less than the lower limit of described threshold amplitude, reclaim roller to described toner and apply the bias voltage that the alternating voltage DC voltage stack opposite with the regular charged characteristic of developer with polarity forms, compare with the approximated position of described two-component developer supporting body and described toner carrier, the toner that near the described toner that disperses that is suspended in described toner carrier and the described two-component developer supporting body is reclaimed reclaims roller and is configured in downstream one side of the sense of rotation of described two-component developer supporting body, and is configured between the wall of described two-component developer supporting body and described housing.
(15) described image forming method can have following formation, that is, the higher limit of described threshold amplitude is 7～20%, and the lower limit of described threshold amplitude is 1～10%.According to described the 2nd image processing system and image forming method, can make the toner that disperses reclaim to catch on the roller and collect and reclaim attached to described toner.And, described toner reclaims roller and comprises applying and be used to reclaim the bias unit of bias voltage of toner of dispersing, by this bias unit, control described bias voltage according to the printing rate, therefore can be further effectively with generating capacity since printing rate and the different toners that disperses be recovered to described toner and reclaim on the roller.As a result, can suppress toner and disperse, obtain picture quality steady in a long-term.
The 3rd image processing system of the present invention and image forming method have following formation.
(16) the 3rd image processing systems comprise in housing at least: the two-component developer supporting body at the internal configurations parts that are magnetic, keeps comprising the developer of carrier and toner by magnetic; And toner carrier, transfer toner by described two-component developer supporting body to self, carry toner thin layer from the teeth outwards; Apply developing bias to described toner carrier and/or described two-component developer supporting body, make the latent electrostatic image developing that on electrostatic latent image supporting body surface, forms, described image processing system is characterised in that, in described housing, be provided with the toner replenishing unit of the described toner of supply, compare with the approximated position of described two-component developer supporting body and described toner carrier, the electrod assembly that near the toner that disperses that is suspended in described toner carrier and the described two-component developer supporting body is reclaimed is configured in downstream one side of the sense of rotation of described two-component developer supporting body, and be configured between the wall of described two-component developer supporting body and described housing, and, described image processing system comprises: bias unit applies to described electrod assembly and to be used to reclaim the bias voltage of toner of dispersing; And control module, control described bias voltage according to the toner replenishing amount of described toner replenishing unit.
(17) described image processing system can have following formation, that is, described toner replenishing unit comprises the toner quantity detection sensor, controls the toner replenishing amount according to the output valve of this toner quantity detection sensor.
(18) described image processing system can have following formation, that is, described electrod assembly is the rotation roller.
(19) described image processing system can have following formation, that is, the peripheral speed of described electrostatic latent image supporting body is more than or equal to 180mm/sec.
(20) described image processing system can have following formation, promptly, described control module carries out the control of described toner replenishing amount in the following manner: according to the output valve of toner quantity detection sensor, the toner replenishing roller that is arranged in the described toner replenishing unit is driven or stop to drive.
(21) described image processing system can have following formation,, under the situation of described toner replenishing amount more than or equal to setting, applies the DC voltage of forcing down than the direct current that imposes on described two-component developer supporting body to described electrod assembly that is.
According to described the 3rd image processing system and image forming method, compare with the approximated position of two-component developer supporting body and toner carrier, the electrod assembly that the toner that disperses is reclaimed is configured in downstream one side of the sense of rotation of described two-component developer supporting body, and be configured between the wall of described two-component developer supporting body and described housing, in addition, comprise applying and be used to reclaim the bias unit of bias voltage of toner of dispersing to electrod assembly, by this bias unit, control described bias voltage according to the toner replenishing amount.Thus, can be further effectively with generating capacity because toner replenishing amount and the different toners that disperses is recovered on the described electrod assembly.As a result, can suppress toner and disperse, obtain picture quality steady in a long-term.
Description of drawings
Fig. 1 is the key diagram of concise and to the point formation of image processing system of the landing visualization way of expression first embodiment of the invention;
Fig. 2 is the concise and to the point pie graph of a part of the developing cell of presentation graphs 1;
Fig. 3 is that expression uses series connection (tandem) the formula coloured image of developing cell shown in Figure 1 to form the concise and to the point pie graph of an example of device;
Fig. 4 reclaims the process flow diagram of the example that the bias voltage of roller controls to imposing on toner in the expression first embodiment of the invention;
Fig. 5 reclaims the process flow diagram of the example that the bias voltage of roller controls to imposing on toner in the variation of expression first embodiment;
Fig. 6 is the figure of an example of the method that the toner concentration detecting unit detects toner concentration in the explanation first embodiment of the invention;
Fig. 7 is the key diagram of concise and to the point formation of image processing system of the landing visualization way of expression second embodiment of the invention;
Fig. 8 is the concise and to the point pie graph of a part of the developing cell of presentation graphs 7;
Fig. 9 reclaims the process flow diagram of the example that the bias voltage of roller controls to imposing on toner in the expression second embodiment of the invention;
Figure 10 reclaims the process flow diagram of other examples that the bias voltage of roller controls to imposing on toner in the expression second embodiment of the invention;
Figure 11 is the key diagram of concise and to the point formation of image processing system of the landing visualization way of expression third embodiment of the invention;
Figure 12 is the concise and to the point pie graph of a part of the developing cell of expression Figure 11;
Figure 13 is the figure of an example of the shape of electrod assembly in expression the 3rd embodiment;
Figure 14 is the figure of an example changing the time of toner container output valve in expression the 3rd embodiment;
Figure 15 is the process flow diagram of an example in expression the 3rd embodiment bias voltage that imposes on electrod assembly being controlled.
Embodiment
＜the first embodiment 〉
Below, explain first embodiment of the present invention with reference to the accompanying drawings.Fig. 1 is the key diagram of concise and to the point formation of image processing system of the landing visualization way of expression first embodiment; Fig. 2 is the concise and to the point pie graph of a part of the developing cell of presentation graphs 1; Fig. 3 is that expression uses the tandem coloured image of developing cell shown in Figure 1 to form the concise and to the point pie graph of an example of device.
(image processing system)
The image processing system of first embodiment is based on the image processing system of so-called landing visualization way, described landing visualization way is meant uses the two-component developer that comprises magnetic carrier 4 and toner 5, on developer roll 2, form toner thin layer 9 by the two-component developer on the carrying left magnetic roller 1, make at photoreceptor 3 (electrostatic latent image supporting body) and go up the latent electrostatic image developing that forms.As shown in Figure 1, this image processing system comprises aforementioned photoreceptor 3, disposes charged elements 8, exposing unit 16, developing cell 18, primary transfer unit 22, secondary transfer printing unit 25, fixation unit 26 and cleaning unit 24 etc. around this photoreceptor 3.
Described image processing system carries out image and forms as getting off.That is, make described photoreceptor 3 charged equably, make this by charged face exposure, form electrostatic latent image by exposing unit 16 by charged elements 8.By toner 5 is attached to from developing cell 18 on the electrostatic latent image that obtains, be developed as the toner picture.This toner picture is by as the primary transfer roller 22 of primary transfer unit and be transferred on the intermediate transfer body (intermediate transfer belt) 20 from photoreceptor 3.And, with the toner of multiple color as overlapping be transferred on the intermediate transfer body 20 after, by secondary transfer roller 25, toner looked like to be transferred to from paper feeding cassette 27 be transported on the transfer printing body of secondary transfer printing position as the secondary transfer printing unit.This transfer printing body is transported to fixing roller 26 places as fixation unit, and here the toner picture, for example is discharged on the discharge tray (not shown) on transfer printing body then by photographic fixing.The lip-deep undeveloped toner that remains in photoreceptor 3 after the transfer printing unit 24 that is cleaned is removed.
As photoreceptor 3, can list inorganic photoreceptors such as selenium, amorphous silicon, and on conductive base, be formed with Organophotoreceptor (OPC) of the photographic layer of individual layer or lamination etc., described photographic layer contains charge generating, charge transfer agent, binding resin etc.As charged elements 8, can list grid electrode charged (scorotron) mode, charged roller, charged brush etc.The exposure light of exposing unit 16 can list LED or semiconductor laser etc.In addition,, for example can list doctor (doctor blade) formula etc., can use known technology respectively as cleaning unit 24.
Developing cell 18 comprises: the magnetic roller 1 (two-component developer supporting body) of cover tubular, and portion's fixed configurations has a plurality of magnetic parts within it, is rotated at the peripheral part of this magnetic part; The developer roll 2 (toner carrier) of cover tubular, portion's fixed configurations has the magnetic part with described magnetic roller 1 heteropole within it, is rotated at the peripheral part of this magnetic part; Limiting scraper 7, the height that is used for the magnetic brush 6 that will be on the left magnetic roller 1 by magnetic field forms remains fixing, and described magnetic field forms by the magnetic force of the mutual different magnetic pole of described magnetic roller 1 and described developer roll 2; And toner reclaims roller 14 (below be also referred to as reclaim roller), is used for reclaiming the toner that disperses.And, comprising: interchange (AC) the bias supply 11a and direct current (DC:Vdc1) the bias supply 11b that apply to magnetic roller 1; Interchange (AC) the bias supply 12a and direct current (DC:Vdc2) the bias supply 12b that apply to developer roll 2; And reclaim interchange (AC) bias supply 13a and direct current (DC:Vdc3) the bias supply 13b that roller 14 applies to toner.And, comprise and detect on the described photoreceptor 3 of the present invention or the image color detecting unit 28 of the concentration of the toner picture on the intermediate transfer body 20.
In addition, image processing system has: toner container (not shown), hold toner 5; And agitating screw 40 and agitating screw 44, will be supplied to the toner 5 of the two-component developer accommodation section 45 that holds two-component developer to stir from this toner container with carrier 4, make it charged.Two agitating screws 40,44 are communicated with at the both ends of dividing plate 42, will be supplied to the part of the two-component developer of agitating screw 44 to be supplied to magnetic roller 1 from agitating screw 40 by this end one side.In agitating screw 44 1 sides, make of the other end one side direction agitating screw 40 one sides circulation of remaining two-component developer from dividing plate 42.In the housing 46 of image processing system, accommodate magnetic roller 1, developer roll 2, agitating screw 40 and agitating screw 44.
The coloured image that described image processing system is suitable for use as is shown in Figure 3,4 photoreceptor 3A, 3B, 3C, 3D are arranged in the tandem (indirect transfer printing series system) on the intermediate transfer body 20 forms device.Wherein, use above-mentioned developing cell 18, but developing apparatus 18A, 18B, 18C, the 18D of the various toners by accommodating magenta, cyan, yellow, black respectively make the electrostatic latent image videoization on described photoreceptor 3A, 3B, 3C, the 3D, form the toner picture respectively.Then, but on described photoreceptor 3A, 3B, 3C, 3D, be transferred to successively on the surface of intermediate transfer body 20 by photoreceptor 3A by the toner picture of videoization from upstream one side.The full-colour image that is transferred on this intermediate transfer body 20 is transferred on the transfer printing body (paper etc.) that transports from paper feeding cassette 27 by secondary transfer roller 25, and by fixing roller 26 photographic fixing, this transfer printing body is discharged from afterwards then.
Here, when the two-component developer on the magnetic roller 1 is recycled in the two-component developer recoverer 45, be compressed by magnetic brush 6, air between the magnetic brush 6 does not enter into two-component developer accommodation section 45 but is rebounded, therefore toner 5 also can be with air from 43 ejections of two-component developer recoverer, thereby produce the described toner that disperses, this is the main generation source of toner of dispersing.In the landing visualization way, magnetic roller 1 with developer roll 2 immediate positions near on developer roll 2 supplying toner 5 and form toner thin layer 9, and peel off and be not used to make not charge image developing toner latent electrostatic image developing, on the developer roll 2 and reclaim, this is the tack of charge image developing toner and carrier 4 little (toner 5 in the two-component developer when forming toner thin layer 9 is compared with the adhesion of carrier 4) not.In addition, owing in the landing visualization way, keep the toner concentration in the two-component developer to such an extent that be higher than common binary visualization way, therefore two-component developer is mobile low, air between the magnetic brush 6 is difficult to enter into two-component developer accommodation section 45 more, therefore toner takes place easily disperse.
In addition, process linear speeds is got over high speed, need more to make the required toner of a plurality of latent electrostatic image developings 5 be transported to developer roll 2 at short notice, opposite because the time of formation toner layer 9 shortens, therefore need take to improve the countermeasures such as toner concentration in the two-component developer.That is, compare during with low speed, after having formed toner layer 9, the toner concentration that is recovered to the two-component developer in the two-component developer accommodation section 45 uprises.In addition, the splitting time of the not charge image developing toner on the developer roll 2 also shortens, and owing to be recovered to the toner concentration height of the two-component developer in the two-component developer recoverer 45, so peel off the difficulty more that becomes.In addition, become the state that toner disperses that also takes place easily, and the toner that disperses sometimes can be attached on the developer roll 2, the amount that reclaims toner increases, the toner easier increase of dispersing.
In addition, in the landing visualization way, there is following method: stable in order to make from developer roll 2 to photoreceptor 3 development, because the charged characteristic of the toner 5 that the deterioration of two-component developer etc. change, stably keep the bed thickness of the toner thin layer 9 on the developer roll 2 by potential difference (PD) Δ V between developer roll 2 and the magnetic roller 1 being changed compensate.This is because development and transfer printing can be because toner carried charges and different, if toner carried charge height for example, then toner thin layer 9 is understood attenuation, and development efficient and the transfer efficiency tendency that all can occur descending.Therefore, at first control the potential difference (PD) Δ V between developer roll 2 and the magnetic roller 1, the toning dosage that stably keeps toner thin layer 9, and also control imposes on the bias voltage of developer roll 2, can stably keep on the photoreceptor 3 thus or the toner concentration on the intermediate transfer body 20 (for example toner concentration of image patch).For example, under the situation that the toner concentration of image patch rises, the toner carried charge is in most of the cases descending.At this moment, toner thin layer 9 thickenings on the developer roll 2, it is excessive that necessary toner quantitative change gets.Therefore, at first adjust the potential difference (PD) Δ V between developer roll 2 and the magnetic roller 1, the toner bed thickness 9 on the described developer roll 2 is controlled to be with just often roughly the same.And, adjust the bias voltage that imposes on described developer roll 2, can stably keep the toner concentration of image patch thus.But, because be difficult to from magnetic brush 6 that left magnetic roller 1 form to direction that developer roll 2 move change to toner 5 this moment, therefore a part that moved to before changing on the developer roll 2 and formed the toner 5 of toner thin layer 9 is not used for the formation of toner thin layer 9, but under as the state in the magnetic brush 6 on the low charged toner 5 residual left magnetic rollers 1, be recycled in the two-component developer accommodation section 45, therefore can become the state of the weak low charged toner 5 of existence adhesion a lot of and carrier 4, be more prone to take place the state that toner disperses thereby become.
Therefore, need to set the bias voltage of the recovery power increase that makes toner reclaim 14 pairs of described toners that disperse of roller.
That is, since the toning dosage that disperses according to the difference of the described Δ V that the thickness of the toner thin layer on the developer roll 2 is revised and therefore difference under the state of the constant bias voltage that imposes on recovery roller 14, can't suppress toner and disperse.And, the toner that disperses can cause that various images are bad, action is bad etc., particularly disperse toner can surface attached to developer roll 2 on, become and take place easily owing to peeling off the bad ghost phenomena that causes, become and hinder one of principal element that preferable image forms.
(toner recovery roller)
Toner reclaims roller 14 and is used for catching and collects the described toner and make it to be back to magnetic roller 1 of dispersing, as shown in Figure 1, in the configuration of photoreceptor 3, developer roll 2, magnetic roller 1 and agitating screw 40,44 constitutes, compare with the approximated position of described magnetic roller 1 and described developer roll 2, this toner reclaims downstream one side that roller 14 is positioned at the sense of rotation of described magnetic roller 1, to stop up the mode and the 1 relative configuration of magnetic roller in described magnetic roller 1 and the gap of housing 46 walls.
By adopting above-mentioned formation, can make the gap of near be suspended in described developer roll 2 and the described magnetic roller 1 the toner that disperses, bottom one side by described magnetic roller 1 and direction of arrow A in Fig. 1 moves and the toner that disperses that in described image processing system, disperses by intermolecular force or electrostatic force etc. and reclaim attached to toner on the surface of roller 14, thereby catch collection.
Described recovery roller 14 gets final product to the circumferencial direction rotation.Thus, can make attached to described recovery roller 14 the lip-deep magnetic brush 6 that forms on toner and the left magnetic roller 1 that disperses to contact and it is peeled off, and make it to turn back to magnetic roller 1 one sides.
The sense of rotation of the sense of rotation of described recovery roller 14 and magnetic roller 1 both can identical (having followed rotation with magnetic roller 1) at its relative position place, also (reverse rotation) on the contrary.Preferably follow rotation.By following rotation, the toner that will reclaim easily on the roller 14 is recovered on the magnetic roller 1 immediately, and owing to be applied to the stress that reclaims on the toner and reduce, so can prevent the toner deterioration that reclaims.
The peripheral speed of described recovery roller 14 is that 10～100mm/sec gets final product, and is preferably 20～70mm/sec.If the peripheral speed of described recovery roller 14 is lower than 10mm/sec, then revolution is few, and the yield of the toner that disperses is undesirable.In addition, if more than or equal to 100mm/sec, the recovery reduction of the toner that then disperses, and may disperse once more when peeling off adhering toner by magnetic brush 6, therefore undesirable.
The material of the turnbarrel of described recovery roller 14 can be used metals such as aluminium, stainless steel.Viewpoint from the tack of the toner that disperses, preferred specific surface area is big and passed through the aluminium that pellumina is handled, perhaps/further from the viewpoint of electrostatic adhesion, preferably by covering surfaces such as fluorine resin (charged characteristic of toner is the situation of positively charged).
Reclaim roller 14 to described toner and apply bias voltage by being used to reclaim the disperse bias unit 13 of toner, use image color detecting unit 28 to control described bias voltage.Promptly, the control of described bias voltage is as follows: the toner concentration that detects the toner picture that is developed by described image color detecting unit 28 on described photoreceptor 3, control bias difference Δ V between described magnetic roller 1 and the described developer roll 2 according to this toner concentration, reclaim roller 14 according to this bias difference Δ V to described toner and apply described bias voltage.
In the control of above-mentioned bias voltage, when controlling bed thickness in the fixed thickness that makes the toner thin layer 9 on the developer roll 2 corresponding to image color, promptly when the bias difference Δ V between magnetic roller 1 and the developer roll 2 is controlled, make when non-image the formation with predetermined timing to impose on the offset change that reclaims roller 14.Its foundation is following opinion: under the low situation of toner carried charge, calculate low value as Δ V, and opposite under the high situation of toner carried charge, calculate high value as Δ V.In addition, as described predetermined timing, can use printing number, some count number, developing drive time to wait and set.Perhaps also can be when carrying out calibration (calibration) action of gray scale adjustment or concentration adjustment.
Owing under the low situation of toner carried charge, reduce Δ V, therefore there is the formation that is not used for toner thin layer 9 and the low charged toner 5 of magnetic brush 6 on the residual left magnetic roller 1, this remaining toner 5 is little with the electrostatic attraction of carrier 4, so toner 5 breaks away from from the surface of carrier 4 easily.Therefore, the toning dosage that disperses can increase.Therefore, under the low situation of Δ V, can reclaim the toner that disperses by on the direction that attracts toner 5, increasing the biasing that imposes on recovery roller 14 more.
In Fig. 4, by flowcharting to imposing on the example that the bias voltage that reclaims roller 14 is controlled.Concentration sensor 28 (hereinafter referred to as the ID sensor) as the image color detecting unit is installed on photoreceptor 3 or intermediate transfer body 20.As shown in Figure 6, this ID sensor 28 for example detects the toner picture (for example patch image of benchmark) that forms on photoreceptor 3.
As described ID sensor 28, can use the reflection-type concentration sensor.Fig. 6 has represented the concise and to the point figure of this reflection-type concentration sensor.The following formation of reflection-type concentration sensor: pass through BS (Beam splitter from the light of LED irradiation, optical splitter) 1 shines to 1 direction polarization and to the toner face, in addition, by PD1 and monitored, remain its light quantity constant to the light of other direction polarization by feedback circuit.Become scattered light from the light of toner face reflection, be divided into two polarized components once more by BS2, and respectively to PD2, PD3 incident.Detect toning dosage by its ratio.
At first, when developing drive time in image forms during, on the surface of photoreceptor 3, form the image patch more than or equal to the driving time of regulation.Come the toner concentration of detected image patch by ID sensor 28.The formation of image patch is regularly just carried out once getting final product through 5～20 minutes for the described developing drive time is every.With reference to predetermined tables of data (relation of toner concentration and toner thin layer thickness), if the toner concentration that obtains is positioned at the scope of regulation, then be judged as the appropriate toner bed thickness, proceed image and form.The suitable scope of described toner bed thickness is 7～18 μ m.In addition, therefore the suitable scope of described toner bed thickness is set suitable scope according to above-mentioned factor and is got final product according to the colour rendering of toner 5, hidden rate, total amount (gross) etc. and different.And, be higher than at toner concentration under the situation of appropriate value, judge that according to described table described toner bed thickness is higher than the scope of regulation, judge that promptly the toner carried charge is low, therefore reduce Δ V.Decide the Δ V of this moment according to predetermined, relevant with Δ V tables of data with the toner bed thickness.
Then, the Δ V of this moment and the threshold value of regulation are compared (with reference to predefined tables of data), under situation, proceed image and form more than or equal to the threshold value of stipulating.Under the situation of threshold value of Δ V, increase the bias voltage Vdc3 of recovery roller 14 to the disperse direction of toner of attractions less than regulation.Then, proceeding image forms.
In addition, also can be as shown in Figure 4, when initial judgement toner concentration is high, after making Δ V change ormal weight, form the image patch once more thereupon, detect this toner concentration by ID sensor 28, before becoming the toner concentration of regulation, repeat said process and decide Δ V, and the Δ V of this moment and the threshold value of regulation are compared.
In addition, when initial judgement toner concentration is high, also can form a plurality of image patches that form thereupon Δ V is changed, and compare with predefined tables of data (relation of toner concentration and toner bed thickness) and to decide Δ V.
On the other hand, when initial judgement toner concentration is low, also after making Δ V change ormal weight, form the image patch once more thereupon, detect this toner concentration by ID sensor 28, before becoming the toner concentration of regulation, repeat said process and be set at suitable Δ V, and proceed image formation.
In addition, as the formation of described image patch parameter regularly,, can also use printing number or some count number except developing drive the time.
In the control of above-mentioned Δ V, particularly, for example (for example under 150～200V) the situation, make the current potential that reclaims roller 14 be lower than the current potential (for example DC voltage Vdc1=300V) of magnetic roller 1 less than the threshold value of stipulating at Δ V.That is, for example making the DC voltage Vdc3 that reclaims roller 14 is 100V.In addition, under the situation of Δ V, make the current potential and the magnetic roller 1 that reclaim roller 14 roughly the same more than or equal to the threshold value of described regulation.Described Δ V, then can be changed according to the degree of dispersing of toner and control if be positioned at this limited field by the characteristic limitations of developer.In addition, the potential difference (PD) that reclaims roller 14 and magnetic roller 1 is changed.For example, the threshold value of Δ V is 190V, is that to make the Vdc3 that reclaims roller 14 under the situation of 180V be 100V at Δ V, is that to make the Vdc3 that reclaims roller 14 under the situation of 170V be that 80V gets final product at Δ V, can take the corresponding corresponded manner of the level of dispersing with toner.As mentioned above, under the situation of Δ V smaller or equal to 190V, as the method that reclaims toner 5 to recovery roller 14 1 sides, only illustrated by DC voltage difference to reclaiming the formation that roller 14 1 sides reclaim toner 5, but also can use in dutycycle, Vpp and the frequency of interchange at least one to reclaim toner 5 to reclaiming roller 14 1 sides.
(developing method)
Fig. 2 has schematically shown the part of developing cell of the present invention.Below, developing method is described.
Comprise by the fixed magnets that holds in the magnetic roller 1 and be subjected on the surface of magnetic brush 6 left magnetic rollers 1 that magnetically confined carrier 4 (magnetic particle) and its surface keeps charged toner 5 rotation and transported to developer roll 2.(blast) processing or groove processing have been carried out spraying in the surface of magnetic roller 1, can transport magnetic brush 6 more swimmingly thus.
As shown in Figure 2, apply the developing bias voltage 12 that DC voltage (DC:Vdc2) 12b and alternating voltage (AC) 12a stack forms to developer roll 2, apply the developing bias voltage 11 of DC voltage (DC:Vdc1) 11b and alternating voltage (AC) 11a stack formation to magnetic roller 1.And, being formed with described magnetic brush 6 on the left magnetic roller 1, the magnetic brush 6 on the magnetic roller 1 is limited scraper plate 7 restriction bed thickness, by the potential difference (PD) between magnetic roller 1 and the developer roll 2, only is that the charged toner 5 of the magnetic brush 6 that is transported moves and forms toner layer 9 to developer roll 2.And, make latent electrostatic image developing on the photoreceptor 3 by the toner layer on the developer roll 29.
Described DC voltage Vdc is a centre of area voltage, changes when dutycycle is changed.In the present invention, in during being equivalent to for 1 cycle of the alternating voltage of square wave, if will be made as T1 to the duration that positive polarity one side applies, will be made as T2 to the duration that negative polarity one side applies, then represent dutycycle by dutycycle (%)=[T1/ (T1+T2)] * 100.The voltage that the waveform that rises to positive polarity one side this moment is equated with area to the waveform of negative polarity one side rising is called centre of area voltage.Also can be as required and the stack DC voltage, under the situation of DC voltage that superposeed, Vdc=DC voltage+centre of area voltage.The Vdc that does not apply under the situation of interchange is simple DC voltage.
Can use on the surface of 16 pairs of photoreceptors 3 of exposing unit by charged elements 8 charged place to expose, thereby on photoreceptor 3, form described electrostatic latent image to+250～800V.If use OPC (Organophotoreceptor), then can obtain+70～220V by full exposure, the amorphous silicon photoreceptor then can obtain the exposure afterpotential of 10～50V.Can use a certain exposure the among semiconductor laser and the LED.
After having carried out as mentioned above developing, the developer roll 2 with remaining toner layer is the most approaching with the magnetic roller 1 with developer layer at its relative position place, strips toner layer 9 on the developer roll 2 at this relative position place by the mechanical force that is produced by magnetic brush 6.Meanwhile, the potential difference (PD) (being electric field) according to forming between left magnetic roller 1 and the developer roll 2 is fed to developer roll 2 one sides with toner 5 from the developer layer on the magnetic roller 1.
When developing, as bias condition, can apply+300～500V to magnetic roller 1, apply+100V to developer roll 2.As the potential difference (PD) that is used to form thin layer, 200～400V is suitable, by and the carried charge of toner 5 between balance adjustment get final product.By using FEEDBACK CONTROL etc., the bed thickness of toner thin layer 9 is fixed.
As the interchange condition, preferably apply the opposite V of the identical and phase place of frequency, cycle and developer roll 2 and developer roll 2 to magnetic roller 1 P-pThe voltage of (peak value AC bias), this V P-p=0.1～2.0kV, frequency=2～4kHz, dutycycle=60～80%, and apply V to developer roll 2 P-pThe voltage of=1.0～2.0kV, frequency=2～4kHz, dutycycle=20～40%.If improve V P-p, then thin layer formation meeting was finished in moment, but opposite anti-electric leakage can weaken, thus cause generating noise.About the premises,, be preferred therefore owing to wait and improve insulativity and can increase allowance by the surface of magnetic roller 1 or developer roll 2 being carried out the pellumina processing.About frequency, the carried charge adjustment by toner 5 gets final product.
The volume average particle size of toner 5 is that 4.0～7.5 μ m get final product.When less than 4.0 μ m, the influence of non-electrostatic adhesive force increases, and development, the reduction of recovery property are and if greater than 7.5 μ m, then be difficult to obtain the image of high-quality such as picture quality smoothness.In addition, the carried charge of toner 5 is preferably about 6～30 μ C/g.When carried charge was lower than 6～30 μ C/g, toner 5 can float and pollutes periphery from magnetic brush 6, and when carried charge was higher than 6～30 μ C/g, thin layer formation can die down.
Can use Miltisizer III (manufacturing of Beckmann Coulter company), measure the toner volume average particle size with aperture 100 μ m (measurement range is 2.0～60 μ m).
In addition, can pass through QM measuring instrument (TREK company makes, and model is 210HS) and measure the toner carried charge.
Carrier 4 can use known carrier, but preferably uses core also to apply the carrier of resin from the teeth outwards as ferrite.Coated with resins can be known resins such as silicon, fluorine-containing epoxy resin, fluorine silicon resin, polyamide, polyamide-imide resin.In addition, carrier particle diameter (weight average particle diameter) is preferably 25～50 μ m.If less than 25 μ m, because a little less than the confining force based on magnetic force, therefore can take place carrier 4 to developer roll 2, reclaim carrier leap that roller 14 moves etc., if and more than or equal to 50 μ m, the density of magnetic brush 6 is improper, and the formation of toner thin layer 9 also has some setbacks, and because specific surface area is little, the recovery of toner 5 also can reduce.And the saturated magnetization of carrier 4 is preferably 35～90emu/g.If saturated magnetization is lower than 35emu/g, then carrier leap can significantly worsen, and if be higher than 90emu/g, then magnetic brush 6 becomes and dredges, and can't form uniform thin layer.
Can use " VSM-P7 " of the manufacturing of TOEI company, measure the saturated magnetization of carrier 4 by magnetic field 79.6kA/m (1kOe).
Magnetic roller 1 is 200～600 μ m with the gap of developer roll 2, is preferably 300～400 μ m.The gap is to be used for the most effective factor that moment forms thin layer.If its amplitude broad then can produce problems such as this efficient reduction, development ghost image.And if narrow, the magnetic brush 6 that then can produce by squeegee gap can't cause problems such as toner thin layer 9 disorders by this gap.
In addition, magnetic roller 1 is the interval that magnetic brush 6 is understood the degree that contact with recovery roller 14 with the gap that toner reclaims roller 14, get final product less than the gap of magnetic roller 1 with developer roll 2, and be 150～500 μ m, be preferably 200～300 μ m.
By making magnetic roller 1 and reclaiming distance between the roller 14, can prevent to disperse to developer roll 2 one sides from the toner that disperses of magnetic roller 1 periphery generation smaller or equal to the distance between magnetic roller 1 and the developer roll 2.If constriction magnetic roller 1 and the gap of reclaiming roller 14 can leak electricity, therefore in order to suppress this electric leakage, need carry out the pellumina processing to the surface of recovery roller 14 and wait and improve insulativity, make it have resistance.At this moment, the resistivity on the surface of recovery roller 14 is 10 7～10 12Ω m gets final product.
(variation of first embodiment)
About impose on the control that toner reclaims the bias voltage of roller 14 by described bias unit 13, also can replace the control in aforementioned first embodiment, and control according to the toner carried charge on the developer roll 2 according to Δ V.But here, the toner carried charge on the developer roll 2 that calculates based on the toner concentration according to the surface potential of developer roll 2 and image patch is controlled.Therefore, in the present embodiment, the surface potential detecting unit 29 of the surface potential that detects developer roll 2 is set, uses the surface potential detecting sensor as this surface potential detecting unit 29.In Fig. 5 by flowcharting in the present embodiment to imposing on the example that the bias voltage that reclaims roller 14 is controlled.
As shown in Figure 5, if the developing drive time is more than or equal to the number counting of regulation when image forms, then at first form the image patch, use ID sensor 28 detects the toner concentration of described image patch, detects the surface potential of the described developer roll 2 of this moment by surface potential detecting sensor 29.And, will be defined as the carried charge of the toner 5 on the developer roll 2 according to the carried charge that above-mentioned testing result is calculated.Under the situation of threshold value of the carried charge that obtains, increase the bias voltage Vdc3 of recovery roller 14 to the disperse direction of toner of attractions less than regulation.
In above-mentioned control, carry out above-mentioned action in the time of also the image patch can being formed in calibration based on the image adjustment.
Particularly, at first when non-image formation, form image patch, the toner concentration that uses ID sensor 28 to detect on the intermediate transfer body 20.Simultaneously, use surface potential sensor 29 to measure the surface potential of the toner thin layer 9 that on developer roll 2, forms.Based on this testing result, calculate the toner carried charge of toner thin layer 9 according to the predetermined tables of data of the relation of representing toner concentration and surface potential and toner carried charge.And, the threshold value of the toner carried charge of the toner carried charge that calculates and pre-prepd toner thin layer 9 is compared, control according to this result and impose on the bias voltage that reclaims roller 14.For example, at the toner carried charge that to make threshold value be 6 μ C/g, calculate is under the situation of 5.5 μ C/g, make the bias voltage Vdc3 that reclaims roller 14 with respect to magnetic roller 1 low 40～60V, the toner that the seizure on feasible the disperse toner and the recovery roller 14 that will suspend is easily collected attracts reclaiming roller 14 1 sides.On the contrary, be higher than under the situation of threshold value, make the bias voltage and the magnetic roller 1 that impose on recovery roller 14 idiostatic at the toner carried charge that calculates.
Simultaneously, adjust Δ V, toner thin layer thickness is remained fixing control with reference to the tables of data of the relation of pre-prepd, expression toner carried charge of toner thin layer 9 and potential difference (PD) Δ V.
＜the second embodiment 〉
Below, explain second embodiment of the present invention with reference to the accompanying drawings.Fig. 7 is the key diagram of concise and to the point formation of image processing system of the landing visualization way of expression present embodiment.Fig. 8 is the concise and to the point pie graph of a part of the developing cell of presentation graphs 7.In addition, about the parts identical, mark identical label and omit explanation with first embodiment.
(image processing system)
The image processing system of present embodiment forms image by aforesaid so-called landing visualization way.As shown in Figure 7, this image processing system comprises photoreceptor 3 (electrostatic latent image supporting body), disposes charged elements 8, exposing unit 16, developing cell 18, primary transfer unit 22, secondary transfer printing unit 25, fixation unit 26 and cleaning unit 24 etc. around this photoreceptor 3.
The described image processing system and first embodiment similarly carry out image and form.
Developing cell 18 comprises: the magnetic roller 1 (two-component developer supporting body) of cover tubular, and portion's fixed configurations has a plurality of magnetic parts within it, is rotated at the peripheral part of this magnetic part; The developer roll 2 (toner carrier) of cover tubular, portion's fixed configurations has the magnetic part with described magnetic roller 1 heteropole within it, is rotated at the peripheral part of this magnetic part; Limiting scraper 7, the height that is used for the magnetic brush 6 that will be on the left magnetic roller 1 by magnetic field forms remains fixing, and described magnetic field forms by the magnetic force of the mutual different magnetic pole of described magnetic roller 1 and described magnetic roller 2; And toner reclaims roller 14 (below be also referred to as reclaim roller), is used for reclaiming the toner that disperses.And, comprising: interchange (AC) the bias supply 11a and direct current (DC:Vdc1) the bias supply 11b that apply to magnetic roller 1; Interchange (AC) the bias supply 12a and direct current (DC:Vdc2) the bias supply 12b that apply to developer roll 2; And reclaim interchange (AC) bias supply 13a and direct current (DC:Vdc3) the bias supply 13b that roller 14 applies to toner.In addition, comprise the control module 15 that the bias voltage that imposes on described toner recovery roller 14 is controlled.
The coloured image that this image processing system is suitable for use as is shown in Figure 3,4 photoreceptor 3A, 3B, 3C, 3D are arranged in the tandem (indirect transfer printing series system) on the intermediate transfer body 20 forms device.
Like that toner takes place in the landing visualization way easily disperse as explanation in the first embodiment, particularly process linear speeds is got over high speed, and it is big more to reclaim the dosage of mixing colours, the toner easy more increase of dispersing.
In addition, under the low situation of printing rate, also be easy to generate the toner that disperses.As mentioned above, be lower than in the printing rate under 5% the situation, the not charge image developing toner that remains on the developer roll 2 is many, this not charge image developing toner be recovered by carrying two-component developer on the left magnetic roller 1, that comprise carrier 4 and toner 5 at least, the two-component developer on magnetic roller 1 is recycled in the two-component developer recoverer 45 in the developing apparatus 18.Therefore, because the amount of the toner that is recovered is many, so the amount of the toner in the two-component developer that is recovered is also many, toner takes place when the two-component developer on the magnetic roller 1 is recycled in the two-component developer recoverer 45 easily disperse.
And, the toner that disperses can cause that various images are bad, action is bad etc., particularly disperse toner can surface attached to developer roll 2 on, become and take place easily owing to peeling off the bad ghost phenomena that causes, become one of principal element that hinders preferable image formation.
(toner recovery roller)
Toner reclaims roller 14 and is used for catching and collects the described toner and make it be back to magnetic roller 1 of dispersing, as shown in Figure 7, in the configuration of photoreceptor 3, developer roll 2, magnetic roller 1 and agitating screw 40,44 constitutes, compare with the approximated position of described magnetic roller 1 and described developer roll 2, this toner reclaims downstream one side that roller 14 is positioned at the sense of rotation of described magnetic roller 1, to stop up the mode and the 1 relative configuration of magnetic roller in described magnetic roller 1 and the gap of housing 46 walls.
By adopting above-mentioned formation, can make the gap of near be suspended in described developer roll 2 and the described magnetic roller 1 the toner that disperses, bottom one side by described magnetic roller 1 and direction of arrow A in Fig. 7 moves and the toner that disperses that in described image processing system, disperses by intermolecular force or electrostatic force etc. and reclaim attached to toner on the surface of roller 14, thereby catch collection.
Described recovery roller 14 gets final product to the circumferencial direction rotation.The sense of rotation of the sense of rotation of described recovery roller 14 and magnetic roller 1 both can identical (having followed rotation with magnetic roller 1) at its relative position place, also (reverse rotation) on the contrary.Preferably follow rotation.The material of the peripheral speed of described recovery roller 14 and the turnbarrel that reclaims roller 14 can be identical with aforementioned embodiments.
Reclaim roller 14 to toner and apply bias voltage by being used to reclaim the disperse bias unit 13 of toner, use control module 15 to control described bias voltage.That is, the control of described bias voltage is according to the printing rate described bias voltage to be imposed on the control that described toner reclaims roller 14.
In image processing system of the present invention, according to image information, by from the scanning element emitted laser, toner image forms on the surface of photoreceptor 3 as the set of the luminous point of the diameter that is converged to several 10 μ m.Therefore, can add up to calculate described printing rate by the laser that constitutes this toner image is counted.
As mentioned above, for example under the printing rate is lower than 5% situation, the not charge image developing toner that remains on the developer roll 2 is many, this not charge image developing toner be recovered by carrying two-component developer on the left magnetic roller 1, that comprise carrier 4 and toner 5 at least, the two-component developer on magnetic roller 1 is recycled in the two-component developer recoverer 45 in the developing apparatus.Therefore, because the amount of the toner that is recovered is many, so the amount of the toner in the two-component developer that is recovered is also many, toner takes place when the two-component developer on the magnetic roller 1 is recycled in the two-component developer recoverer easily disperse.
Therefore, by apply the opposite biasing of polarity and toner 5 to the electrode that reclaims roller 14, attract, reclaim the suspension toner that disperses easily, and also attract toner 5 from magnetic roller 1, therefore before the two-component developer on the left magnetic roller 1 is recycled in the two-component developer recoverer 45, the amount of the toner in the two-component developer reduces, and has suppressed the toner dispersion.
In addition, for example under the printing rate was 5～15% situation, the amount of charge image developing toner was unsuitable, for being difficult for taking place the state that toner disperses.The current potential height of magnetic roller 1 under the state that does not apply direct current biasing, the toner that therefore disperses is attracted by the electrode of the low relatively recovery roller 14 of current potential, also attracts toner 5 from magnetic roller 1 owing to same as described above in addition, therefore can suppress toner and disperse.In addition, by not applying direct current biasing, also can suppress power consumption.
In addition, for example the printing rate more than or equal to 15% situation under, the not charge image developing toner on the developer roll 2 is few, the amount of the toner that reclaims by magnetic roller 1 also tails off.Toner when therefore, the two-component developer on the magnetic roller 1 is recycled in the two-component developer accommodation section 45 disperses and becomes considerably less.Therefore, by apply the superimposed voltage that the identical direct current biasing of polarity and toner 5 and AC bias stack form to the electrode that reclaims roller 14, can be from the electrode attraction toner 5 of magnetic roller 1 to recovery roller 14.Preferably, the current potential that imposes on the direct current biasing of the electrode that reclaims roller 14 is equal to or higher than the current potential of magnetic roller 1.
In Fig. 9 by flowcharting to imposing on the example that the bias voltage that reclaims roller 14 is controlled.Apply AC bias voltage to reclaiming roller 14 in the time of in the early stage.According to counting of the toner picture that when image forms, on photoreceptor 3, forms, calculate the printing rate by analysis means (not shown).
Then, to the threshold value of the printing rate that calculates and regulation, for example 5～10% compare.Under the situation of printing rate more than or equal to the threshold value of regulation, do not change the biasing that imposes on recovery roller 14, only continue to apply AC bias voltage.Under the situation of threshold value of printing rate, to reclaiming the opposite polarity DC voltage that roller 14 applies polarity and regular charged characteristic toner smaller or equal to regulation.
In Figure 10, represented imposing on other examples that the bias voltage that reclaims roller 14 is controlled.In the time of in the early stage, only apply AC bias voltage (biasing B) to reclaiming roller 14.According to counting of the toner picture that when image forms, on photoreceptor 3, forms, calculate the printing rate by analysis means (not shown).
Then, the printing rate is set at the threshold amplitude of regulation, for example the lower limit with this threshold amplitude is set at 1～10%, be preferably set to about 5%, higher limit is set at 7～20%, be preferably set to about 15%, will be less than the scope of the printing rate of described threshold value lower limit as printing rate scope A, will be more than or equal to described threshold value lower limit, less than the scope of the printing rate of higher limit as printing rate scope B, and will described printing rate that calculates and printing last time rate scope be compared more than or equal to the scope of the printing rate of described upper threshold value as printing rate scope C.
Do not cross in the printing rate under the situation of described threshold value (identical), impose on the biasing that applies of reclaiming roller 14 and do not change, continue to apply the biasing that applies of last time with the printing rate scope of last time.Cross downwards in the printing rate under the situation of the higher limit of described threshold value or lower limit, apply biasing according to the printing rate scope of this moment.That is, the printing rate be positioned at printing rate scope A (the printing rate scope of last time is B or C) with situation under, apply the bias voltage (applying biasing A) that the opposite DC voltage stack of regular charged characteristic of alternating voltage and polarity and developer forms.The printing rate be positioned at printing rate scope B (the printing rate scope of last time is C) with situation under, apply bias voltage that alternating voltage is only arranged (applying biasing B).Upwards cross in the printing rate under the situation of the higher limit of described threshold value or lower limit, constantly the output number of printing is counted, when more than or equal to the number of regulation, for example 2～5 the time, apply biasing according to the printing rate scope of this moment from this.That is, the printing rate be positioned at printing rate scope C (the printing rate scope of last time is A or B) with situation under, apply the bias voltage (applying biasing C) that the DC voltage stack identical with the regular charged characteristic of developer of alternating voltage and polarity forms.The printing rate be positioned at printing rate scope B (the printing rate scope of last time is A) with situation under, apply bias voltage that alternating voltage is only arranged (applying biasing B).
The reasons are as follows of count restrictions of output number is set in the above description.That is, even the printing rate changes, toner disperses and also can not reduce immediately, and the quite a long time inner suspension toner after toner disperses beginning exists all the time.Therefore, for example the printing rate of dispersing from easy generation toner less than 5% change into the printing rate more than or equal to 5% situation under, be 5～15% to change under the situation of printing rate more than or equal to 15% state from the printing rate perhaps, the preferred setting that applies biasing of not changing toner recovery roller 14 immediately, but in the quite a long time, for example before 2～3 end of output during in keep former state, and then change and to apply biasing., may toner take place immediately and disperse under the situation that the direction that reduces changes in the printing rate, therefore apply biasing and change immediately.
In addition, owing to can go out the printing rate, therefore can change and apply biasing, be equivalent to several～ten number Zhang Chengdu, 10 average printing rate for example, and change in view of the above and apply biasing but also can calculate at per 1 image at per 1 image calculation.
On described recovery roller 14, can be provided with and reclaim scraper plate 17 (with reference to Fig. 7).Can reclaim scraper plate 17 by this and scrape that getting is captured and be collected in the toner that reclaims on the roller 14, and make it to be back to agitating screw 40.In this case, described recovery scraper plate 17 is configured in agitating screw 40 1 sides, can contact with the surface of reclaiming roller 14 with certain pressure.The sense of rotation of described recovery roller 14 is for getting final product to the direction rotation that is back to screw rod 40 in the position relative with magnetic roller 1, direction by making described rotation is to the direction rotation of agitating screw 40, can easily be recycled to agitating screw 40 1 sides by the toner that disperses that reclaims on the described recovery roller 14 that scraper plate 17 peels off.In addition, described recovery scraper plate 17 also can be used to limit the thickness of the toner layer that is formed by the toner that reclaims.At this moment, described recovery scraper plate 17 is configured to and reclaims the interval of the surperficial partition distance of roller 14 for the expectation bed thickness.Thus, can thickening owing to reclaim bed thickness that seizure on the roller 14 collects toner, therefore can scrape by magnetic brush 6 well and get, and can prevent to scrape dispersing once more of toner when getting.
But, the described recovery scraper plate 17 of taking of scraping also can be set.At this moment, when non-image form, apply to make to reclaim and be accumulated in toner and reclaim the biasing that the toner that disperses on the roller 14 is back to magnetic roller 1.Applying under the situation of biasing, for example be set to toner recovery roller 14 and apply following voltage: Vdc3=100V, Vpp=300V, frequency f=2.7kHz, dutycycle=30% that phase place and magnetic roller 1 are opposite, apply following voltage: Vdc1=-100V to the magnetic roller, Vpp=300V, frequency f=2.7kHz, dutycycle=70% that phase place and developer roll 2 are opposite.At this moment, because toner 5 can not move yet between developer roll 2 and magnetic roller 1, therefore can not apply biasing to developer roll 2.Under situation about applying, apply following voltage and get final product: Vdc2=100V, Vpp=1.6kV, frequency f=2.7kHz, dutycycle=30%.
With reclaim and compare by reclaiming scraper plate 17, by applying biasing adhering toner is recovered to the mode of magnetic roller 1 one sides as mentioned above because can not be subjected to and scraper plate 17 between stress influence and can obtaining reduce the effect that buries or peel off etc. the deterioration of toner 5 of the additive of toner 5.
(developing method)
Fig. 8 has schematically shown the part of developing cell of the present invention.Similarly develop with situation about in aforementioned first embodiment, illustrating according to Fig. 2.
After having carried out developing, the developer roll 2 with remaining toner layer is the most approaching with the magnetic roller 1 with developer layer at its relative position place, strips toner layer 9 on the developer roll 2 at this relative position place by the mechanical force that is produced by magnetic brush 6.Meanwhile, the potential difference (PD) (being electric field) according to forming between left magnetic roller 1 and the developer roll 2 is fed to developer roll 2 one sides with toner 5 from the developer layer on the magnetic roller 1.Bias condition during development is with to exchange condition identical with aforementioned first embodiment.
＜the three embodiment 〉
Below, explain embodiments of the present invention with reference to the accompanying drawings.Figure 11 is the key diagram of concise and to the point formation of image processing system of the landing visualization way of expression one embodiment of the present invention.Figure 12 is the concise and to the point pie graph of a part of the developing cell of expression Figure 11.About the parts mark identical identical label and omission explanation with first, second embodiment.
(image processing system)
Image processing system of the present invention forms image by aforesaid so-called landing visualization way.As shown in figure 11, this image processing system comprises aforementioned photoreceptor 3 (electrostatic latent image supporting body), disposes charged elements 8, exposing unit 16, developing cell 18, primary transfer unit 22, secondary transfer printing unit 25, fixation unit 26, cleaning unit 24 and toner replenishing unit 47 etc. around this photoreceptor 3.
The described image processing system and first embodiment similarly carry out image and form.
Developing cell 18 comprises: the magnetic roller 1 (two-component developer supporting body) of cover tubular, and portion's fixed configurations has a plurality of magnetic parts within it, is rotated at the peripheral part of this magnetic part; The developer roll 2 (toner carrier) of cover tubular, portion's fixed configurations has the magnetic part with described magnetic roller 1 heteropole within it, is rotated at the peripheral part of this magnetic part; Limiting scraper 7, the height that is used for the magnetic brush 6 that will be on the left magnetic roller 1 by magnetic field forms remains fixing, and described magnetic field forms by the magnetic force of the mutual different magnetic pole of described magnetic roller 1 and described magnetic roller 2; And electrod assembly 14 ', be used for reclaiming the toner that disperses.And, comprising: interchange (AC) the bias supply 11a and direct current (DC:Vdc1) the bias supply 11b that apply to magnetic roller 1; Interchange (AC) the bias supply 12a and direct current (DC:Vdc2) the bias supply 12b that apply to developer roll 2; And to interchange (AC) the bias supply 13a and direct current (DC:Vdc3) the bias supply 13b of electrod assembly 14 ' apply.In addition, comprise to impose on described electrod assembly 14 ' the control module 15 controlled of bias voltage '.
In addition, image processing system of the present invention comprises: toner container 47, hold toner 5 as the toner replenishing unit; And housing 46, accommodate magnetic roller 1, developer roll 2, agitating screw 40 and agitating screw 44.Agitating screw 40 and agitating screw 44 will be supplied to the toner 5 of the two-component developer accommodation section 45 that holds two-component developer to stir with carrier 4 from toner container 47, make it charged.Two agitating screws 40,44 are communicated with at the both ends of dividing plate 42, will be supplied to the two-component developer of agitating screw 44 to be supplied to magnetic roller 1 from agitating screw 40 by this end one side.Agitating screw 44 makes the other end one side direction agitating screw 40 one sides circulation of remaining two-component developer from dividing plate 42.
The coloured image that described image processing system is suitable for use as is shown in Figure 3,4 photoreceptor 3A, 3B, 3C, 3D are arranged in the tandem (indirect transfer printing series system) on the intermediate transfer body 20 forms device.
As illustrating in the aforementioned embodiments, toner takes place easily in the landing visualization way to disperse, particularly process linear speeds is got over high speed, and it is big more to reclaim toning dosage, the toner easy more increase of dispersing.
In addition, the also easy toner that disperses under the many situations of toner replenishing amount.As mentioned above, when the toner replenishing amount for a long time, promptly when the driving time of toner replenishing roller 48 is long or under situations such as the revolution of toner replenishing roller 48 accelerates, the toner 5 of supply sometimes can just be transported near the magnetic roller 1 when frictional electrification is insufficient, because a little less than the adhesion of charged inadequate toner 5 and carrier 4, therefore can since centrifugal force that the rotation by magnetic roller 1 produce or magnetic brush 6 pressure when being recycled in the two-component developer accommodation section 45 etc. and breaking away from from carrier 4 disperse thereby toner takes place easily.
(electrod assembly)
Electrod assembly 14 ' be used for is caught and is collected the described toner and make it to be back to magnetic roller 1 of dispersing, as shown in figure 11, in the configuration of photoreceptor 3, developer roll 2, magnetic roller 1 and agitating screw 40,44 constitutes, compare with the approximated position of described magnetic roller 1 and described developer roll 2, this electrod assembly 14 ' be positioned at downstream one side of the sense of rotation of described magnetic roller 1 is to stop up the mode and the 1 relative configuration of magnetic roller in described magnetic roller 1 and the gap of housing 46 walls.
By adopting above-mentioned formation, can make the gap of near be suspended in described developer roll 2 and the described magnetic roller 1 the toner that disperses, bottom one side by described magnetic roller 1 and direction of arrow A in Figure 11 moves and the toner that disperses that in described image processing system, disperses by intermolecular force or electrostatic force etc. attached to described electrod assembly 14 ' the surface on, thereby catch collection.
As shown in figure 13, described electrod assembly 14 ' shape can list writing board shape, the face relative with magnetic roller 1 for the shape of the surperficial roughly the same curved surface of described magnetic roller 1 or roll shape etc., as long as stop up between described magnetic roller 1 and housing 46 walls the gap and with the 1 relative configuration of magnetic roller, but not be defined in above-mentioned shape especially.Be the to disperse recovery of toner of preferred roll shape, its reason is good, and the toner that disperses of recovery is back in the two-component developer accommodation section 45 by the magnetic brush 6 that forms on the left magnetic roller 1.
In addition, at described electrod assembly 14 ' be under the situation of roll shape, this roller gets final product to the circumferencial direction rotation.Thus, can make attached to described roller the lip-deep magnetic brush 6 that forms on toner and the left magnetic roller 1 that disperses to contact and it is peeled off, and make it to be back to magnetic roller 1 one sides.Roller 14 ' the sense of rotation of sense of rotation and magnetic roller 1 both can identical (having followed rotation) at its relative position place with magnetic roller 1, also (reverse rotation) on the contrary.Preferably follow rotation.
The peripheral speed of described roller is that 5～100mm/sec gets final product, and is preferably 10～70mm/sec.If the peripheral speed of described roller is lower than 5mm/sec, then revolution is few, and the yield of the toner that disperses is undesirable.In addition, if more than or equal to 100mm/sec, the recovery reduction of the toner that then disperses, and may disperse once more when peeling off adhering toner by magnetic brush 6, therefore undesirable.
Described electrod assembly 14 ' material can use aluminium, stainless steel metals such as (SUS).Viewpoint from the tack of the toner that disperses, preferred specific surface area is big and passed through the aluminium that pellumina is handled, perhaps/further from the viewpoint of electrostatic adhesion, preferably by covering surfaces such as fluorine resin (charged characteristic of toner is the situation of positively charged).
In addition, at described electrod assembly 14 ' be under the situation of roll shape, also can take following mode: receive the lip-deep toner that disperses back and forth by magnetic brush 6 attached to roller, and by removing, reclaim residual toner with the recovery scraper plate 17 of the surperficial butt configuration of roller.Reclaim the material of scraper plate 17 and can use material known such as urethane rubber.
Disperse the bias unit 13 of toner to electrod assembly 14 ' apply bias voltage by being used to reclaim, use the described bias voltage of control module 15 ' control.That is, the control of described bias voltage be according to the toner replenishing amount and with described bias voltage impose on described electrod assembly 14 ' control.
That is, be under the situation of positively charged at the charged characteristic of toner 5, when the toner replenishing amount for a long time, by make described electrod assembly 14 ' the current potential current potential that is lower than magnetic roller 1 catch and collect the toner that disperses.Charged characteristic at toner 5 is under the electronegative situation, make on the contrary described electrod assembly 14 ' the current potential current potential that is higher than magnetic roller 1 get final product.That is, apply and be more prone to attract biasing to get final product with the charged toner 5 of regular charged characteristic.Therefore, most preferably apply the opposite biasing of polarity and toner 5.Under the situation that applies the opposite biasing of polarity and toner 5,, therefore can further suppress toner and disperse because also the two-component developer from the magnetic roller 1 directly attracts toner 5.In addition, be temporary owing to the toner that is caused by toner replenishing disperses, therefore as long as mix fully, the frictional electrification of toner 5 will become enough values, disperses thereby can suppress toner.Therefore, reclaim, as long as timing during by toner replenishing in addition makes the toner of recovery be back to magnetic roller 1 as long as at least temporarily the toner that disperses is carried out supply.
In the control of toner replenishing, according to according to the output valve of exporting from the detection signal of the toner quantity detection sensor 49 of the bottom that is configured in agitating screw 40 (hereinafter referred to as the toner container output valve), the increment to the toner 5 of two-component developer accommodation section 45 supplies is controlled in the driving of the toner replenishing roller 48 of control toner container 47 thus.As toner quantity detection sensor 49, can use magnetic sensor, piezoelectric sensor etc., preferred magnetic sensor.Toner quantity sensor 49 also can be arranged on the sidepiece of agitating screw 40.
Figure 14 has represented the example that the time of toner container output valve changes.In toner container output waveform shown in Figure 14, voltage is changed into height (Vmax), low (Vmin) (solid line among Figure 14) according to the swing circle of agitating screw 40.And, if the toner concentration that has consumed in toner, the developer owing to printing reduces, waveform such rising shown in dotted line then, Vmax becomes V ' max.On the contrary, if supply toner, toner concentration rise, then waveform descends, V ' max becomes Vmax.Here, if the value of Vmax then drives the toner replenishing roller and carries out toner replenishing more than or equal to threshold value (TARGET value), if the value of Vmax becomes smaller or equal to threshold value, then control so that the toner replenishing roller stops, toner concentration is remained constant.
Carrying out the toner replenishing method of supply from toner container 47, the for example supply at intermittence that changes for the ON/OFF that makes toner replenishing roller 48 according to the toner container output valve, according to the voltage difference of toner container output valve and threshold value (TARGET value), carry out the time set of ON/OFF by following 5 stages.
(1) under the situation of toner container output valve: ON (0.2 second)/OFF (0.6 second) less than TARGET value+0.2V
(2) the toner container output valve less than TARGET value+0.2V～+ situation of 0.4V under: ON (0.4 second)/OFF (0.6 second)
(3) the toner container output valve less than TARGET value+0.4V～+ situation of 0.6V under: ON (0.6 second)/OFF (0.6 second)
(4) the toner container output valve less than TARGET value+0.6V～+ situation of 0.8V under: ON (0.6 second)/OFF (0.4 second)
(5) under the situation of toner container output valve: ON (0.6 second)/OFF (0.2 second) more than or equal to TARGET value+0.8V
Under the situation of toner replenishing control at intermittence as described above, if the ON/OFF ratio uprises, then can cause the carried charge deficiency, so toner disperses and the tendency that increases can occur owing to the stirring of supply toner.Therefore, under the situation of above-mentioned (4), (5), with described electrod assembly 14 ' the voltage that applies change into low voltage from the current potential identical and get final product with magnetic roller 1.
In addition, drive under the situation of toner replenishing roller 48, be set at the toner 5 of supplying with about 0.2g in time with 0.2 second.In addition, as TARGET value as described in getting off to set: make toner concentration become appropriate concentration,, for example become 5～15% although this particle diameter according to the carrier 4 that uses changes.
In Figure 15 by flowcharting to impose on electrod assembly 14 ' an example controlling of bias voltage.In the time of in the early stage to electrod assembly 14 ' apply AC bias voltage with magnetic roller 1 same potential.When forming, image obtains the toner container output valve by toner quantity detection sensor 49.
Then, as previously mentioned, the voltage difference of toner container output valve that relatively obtains and threshold value (TARGET value).For example, under the situation of toner container output valve less than TARGET value+0.6V, do not change impose on electrod assembly 14 ' bias voltage and continue to apply.And, under the situation of toner container output valve, when the charged characteristic of regular toner 5 is positively charged, change DC voltage more than or equal to TARGET value+0.6V, so that electrod assembly 14 ' become the current potential lower than the current potential of magnetic roller 1.Charged characteristic at regular toner 5 is under the electronegative situation, changes DC voltage according to the mode that becomes the current potential higher than the current potential of magnetic roller 1 on the contrary.
In addition, change impose on electrod assembly 14 ' the toner container output valve of bias be preferably greater than and equal TARGET value+0.6v, but the generating capacity of toner can change according to toner carried charge, toner size-grade distribution, toner particle diameter, magnetic roller peripheral speed etc. owing to disperse, and therefore suitably is set at optimal value according to above-mentioned factor and gets final product.
In addition, also can judge the increase and decrease of described toner replenishing amount according to the variation of the driving time of toner replenishing roller 48.That is,, also can use the driving time of the regulation of toner replenishing roller 48 as the setting of described toner replenishing amount.
Can by apply when non-image form be used to make disperse biasing that toner is back to magnetic roller 1 make adhere to, be accumulated in described electrod assembly 14 ' on the toner that disperses be back to magnetic roller 1.At this moment, for example be set at Vpp=300V, frequency f=2.7kHz, dutycycle=30% that phase place and magnetic roller 1 are opposite to electrod assembly 14 ' apply following voltage: Vdc3=500V.
Like this, by applying biasing, will attached to electrod assembly 14 ' on the toner that disperses be recovered to magnetic roller 1 one sides, can not be subjected to stress influence thus, therefore can obtain to reduce the effect that buries or peel off etc. the deterioration of toner 5 of the additive of toner 5.
(developing method)
Figure 12 has schematically shown the part of developing cell of the present invention.Similarly develop with situation about in aforementioned embodiments, illustrating according to Fig. 2.
After having carried out developing, the developer roll 2 with remaining toner layer is the most approaching with the magnetic roller 1 with developer layer at its relative position place, strips toner layer 9 on the developer roll 2 at this relative position place by the mechanical force that is produced by magnetic brush 6.Meanwhile, the potential difference (PD) (being electric field) according to forming between left magnetic roller 1 and the developer roll 2 is fed to developer roll 2 one sides with toner 5 from the developer layer on the magnetic roller 1.Bias condition during development is with to exchange condition identical with aforementioned first embodiment.
Magnetic roller 1 and electrod assembly 14 ' the gap be magnetic brush 6 can with the interval of the degree of electrod assembly 14 ' contact, get final product less than the gap of magnetic roller 1 and developer roll 2, be 150～500 μ m, be preferably 200～300 μ m.
By make magnetic roller 1 and electrod assembly 14 ' between distance smaller or equal to the distance between magnetic roller 1 and the developer roll 2, can prevent to disperse to developer roll 2 one sides from the toner that disperses that magnetic roller 1 periphery produces.If constriction magnetic roller 1 and electrod assembly 14 ' the gap, can leak electricity, therefore in order to suppress this electric leakage, need to electrod assembly 14 ' the surface carry out the pellumina processing and wait and improve insulativity, make it have resistance.At this moment, electrod assembly 14 ' the resistivity on surface be 10 7～10 12Ω m gets final product.
Below, exemplify embodiment and explain the present invention, but the invention is not restricted to following examples.
[embodiment 1]
Made image processing system of the present invention shown in Figure 1 by following method.The size of each sleeve of photoreceptor 3, developer roll 2, magnetic roller 1 and recovery roller 14 is as follows.
Photoreceptor 3: external diameter 30mm
Developer roll 2: external diameter 20mm
Magnetic roller 1: external diameter 25mm
Reclaim roller 14: external diameter 10mm
Photoreceptor 3 uses the amorphous silicon photoreceptor drum, and the sleeve of each roller uses aluminium respectively.
In addition, the peripheral speed of photosensitive drums and each roller is as follows.In addition, the sense of rotation that reclaims roller 14 is for to follow rotation with magnetic roller 1, promptly rotates to identical direction (direction of returning to screw rod 40) each other reclaiming roller 14 and magnetic roller 1 immediate position.
Photoreceptor 3:300mm/sec
Developer roll 2:450mm/sec
Magnetic roller 1:675mm/sec
Reclaim roller 14:30mm/sec
In addition, as image color detecting unit 28, the concentration sensor that has companies such as Omron, NICHICON, STANLEY to make, the concentration sensor that uses STANLEY company to make in the present embodiment.
Condition when using the image processing system of making as mentioned above to form image is as follows.
Photosensitive surface current potential :+310V
The Q/m:20 μ C/g of the toner in the developer
Toner particle diameter (volume average particle size): 6.7 μ m
Carrier particle diameter (weight average particle diameter): 45 μ m
Distance between magnetic roller and the developer roll: 350 μ m
Distance between magnetic roller and the recovery roller: 500 μ m
Developer roll applies voltage: Vdc2=100V, Vp-p=1.6kV, frequency f=2.7kHz, dutycycle=30%
The magnetic roller applies voltage: Vdc1=300V, the Vp-p=300V that the cycle is identical with developer roll, phase place is opposite, frequency f=2.7kHz, dutycycle=70%
Reclaim roller and apply voltage: the threshold value of Δ V is 200V, the Vdc3=440V when applying (only applying DC voltage)
Developing drive time counting: 10 minutes
[embodiment 2]
Control the voltage that applies that reclaims roller 14 according to toner carried charge (surface potential of developer roll 2), except parameter shown below, made image processing system similarly to Example 1.In addition, as surface potential detecting unit 29, the surface potential detecting sensor of having used TDK company to make.
The Q/m:22 μ C/g of the toner in the developer
Toner particle diameter (volume average particle size): 6.5 μ m
Carrier particle diameter (weight average particle diameter): 42 μ m
Developer roll applies voltage: Vdc2=150V, Vp-p=1.6kV, frequency f=2.7kHz, dutycycle=27%
The magnetic roller applies voltage: Vdc1=300V, the Vp-p=300V that the cycle is identical with developer roll, phase place is opposite, frequency f=2.7kHz, dutycycle=73%
Reclaim roller and apply voltage: change according to the surface potential of developer roll 2 and control the Vdc3=350V when applying (only applying DC voltage)
By above-mentioned explanation as can be known, using following image processing system to carry out to reclaim the toner that disperses effectively when image forms according to above-mentioned condition, and the deterioration of inhibition toner, stably carrying out preferable image forms, in described image processing system, compare with the approximated position of magnetic roller and developer roll, the disperse toner of toner of recovery is reclaimed downstream one side that roller is configured in the sense of rotation of described magnetic roller, and be configured between the wall of described magnetic roller and housing, receive back and forth attached to the toner that disperses on the described toner recovery roller by described magnetic roller.
[embodiment 3]
Made image processing system of the present invention shown in Figure 7 by following method.The size of each sleeve of photoreceptor 3, developer roll 2, magnetic roller 1 and recovery roller 14 is as follows.
Photoreceptor 3: external diameter 30mm
Developer roll 2: external diameter 20mm
Magnetic roller 1: external diameter 25mm
Reclaim roller 14: external diameter 10mm
The photosensitive drums of photoreceptor 3 is used amorphous silicon, and the sleeve of each roller uses aluminium respectively.
In addition, the peripheral speed of each photosensitive drums is as follows.In addition, the sense of rotation that reclaims roller 14 is for to follow rotation with magnetic roller 1, promptly rotates to identical direction (direction of returning to screw rod 40) each other reclaiming roller 14 and magnetic roller 1 immediate position.
Photoreceptor 3:300mm/sec
Developer roll 2:450mm/sec
Magnetic roller 1:675mm/sec
Reclaim roller 14:30mm/sec
Condition when using the image processing system of making as mentioned above to form image is as follows.
Photosensitive surface current potential :+310V (the exposure afterpotential is 20V)
The Q/m:20 μ C/g of the toner in the developer
Toner particle diameter (volume average particle size): 6.8 μ m
Carrier particle diameter (weight average particle diameter): 45 μ m
Distance between magnetic roller and the developer roll: 350 μ m
Distance between magnetic roller and the recovery roller: 250 μ m
Distance between developer roll and the recovery roller: 1000 μ m
Developer roll applies voltage: Vdc2=100V, Vp-p=1.6kV, frequency f=2.7kHz, dutycycle=30%
The magnetic roller applies voltage: Vdc1=300V, the Vp-p=300V that the cycle is identical with developer roll, phase place is opposite, frequency f=2.7kHz, dutycycle=70%
Reclaim roller and apply voltage:
(1) printing rate is less than 5%; Vdc3=-100V, Vp-p=300V, the frequency f=2.7kHz that phase place is opposite with the magnetic roller, dutycycle=30%
(2) printing rate is 5～15%; Vdc3=0V, Vp-p=300V, the frequency f=2.7kHz that phase place is opposite with the magnetic roller, dutycycle=30%
(3) printing rate is more than or equal to 15%; Vdc3=300V, Vp-p=300V, the frequency f=2.7kHz that phase place is opposite with the magnetic roller, dutycycle=30%
Output count number: 10
By above-mentioned explanation as can be known, using following image processing system to carry out to reclaim the toner that disperses effectively when image forms according to above-mentioned condition, and the deterioration of inhibition toner, stably carrying out preferable image forms, in described image processing system, compare with the approximated position of magnetic roller and developer roll, the disperse toner of toner of recovery is reclaimed downstream one side that roller is configured in the sense of rotation of described magnetic roller, and be configured between the wall of described magnetic roller and housing, receive back and forth attached to the toner that disperses on the described toner recovery roller by described magnetic roller.
[embodiment 4]
Made image processing system of the present invention shown in Figure 11 by following method.As electrod assembly 14 of the present invention ', use the roller electrode.The size of each sleeve of photoreceptor 3, developer roll 2, magnetic roller 1 and recovery roller 14 is as follows.
Photoreceptor 3: external diameter 30mm
Developer roll 2: external diameter 20mm
Magnetic roller 1: external diameter 25mm
Roller electrode (electrod assembly 14 '): external diameter 10mm
The photosensitive drums of photoreceptor 3 is used amorphous silicon, and the sleeve of each roller uses aluminium respectively.In addition, the peripheral speed of each photosensitive drums is as follows.
Photoreceptor 3:300mm/sec
Developer roll 2:450mm/sec
Magnetic roller 1:675mm/sec
Roller electrode 14:30mm/sec
Condition when using the image processing system of making as mentioned above to form image is as follows.
Photosensitive surface current potential :+310V (the exposure afterpotential is 20V)
The Q/m:27 μ C/g of the toner in the developer
Toner particle diameter (volume average particle size): 7.0 μ m
Carrier particle diameter (weight average particle diameter): 45 μ m
Distance between magnetic roller and the developer roll: 350 μ m
Developer roll and roller distance between electrodes: 1000 μ m
Magnetic roller and roller distance between electrodes: 250 μ m
Developer roll applies voltage: Vdc2=100V, Vp-p=1.6kV, frequency f=2.7kHz, dutycycle=30%
The magnetic roller applies voltage: Vdc1=300V, the Vp-p=300V that the cycle is identical with developer roll, phase place is opposite, frequency f=2.7kHz, dutycycle=70%
Change the toner container output setting of roller electrode application voltage: TARGET value+0.8V roller electrode application voltage:
(1) initial stage and toner container output valve are smaller or equal to TARGET value+0.8V; Vdc3=300V, Vp-p=300V, the frequency f=2.7kHz that phase place is opposite with the magnetic roller, dutycycle=30%
(2) the toner container output valve is more than or equal to TARGET value+0.8V; Vdc3=200V, Vp-p=300V, the frequency f=2.7kHz that phase place is opposite with the magnetic roller, dutycycle=30%
[ embodiment 5,6, comparative example 1]
Except the toner container output valve is replaced with the value shown in the table 1 more than or equal to the Vdc3 under the situation of TARGET value+0.8V, embodiment 5,6 and comparative example 1 have been made according to the condition identical with embodiment 1.In addition, therefore irrelevant owing to Vdc3=300V in comparative example 1 with the toner replenishing amount, do not change afterwards in the early stage.
(evaluation)
Use the image processing system of as above making, inhomogeneous the dispersing with toner of image estimated by evaluation method as follows and metewand.
(image is inhomogeneous)
Exporting continuously after 510 printing rates are 2% original copy, the output half tone image, by Visual Confirmation image inhomogeneous (density unevenness is even), and estimate image is inhomogeneous according to metewand shown below.
Zero: do not exist image inhomogeneous
*: exist image inhomogeneous
(toner disperses)
Continuously 510 printing rates of output are 2% original copy, by Visual Confirmation after 10 and the degree of adhesion of the toner that disperses on the roller electrodes 14 after 510, and according to metewand shown below toner is dispersed and to estimate.Evaluation result is as shown in table 1.
◎: almost do not have difference after 10 with after 510
There is a little difference after zero: 10 with after 510
△: have difference after 10 with after 510, piled up a little toner that disperses
*: there is difference after 10 with after 510, piled up the toner that disperses significantly
Above-mentioned evaluation result is as shown in table 1.
Table 1
Electrod assembly The magnetic roller Image is inhomogeneous Toner disperses
Vdc3 (V) Dutycycle (%) Vdc1 (V) Dutycycle (%)
Embodiment 4 200 30 300 70 ○ ○
Embodiment 5 0 30 300 70 ○ ○
Embodiment 6 -100 30 300 70 ○ ◎
Comparative example 1 300 30 300 70 × ×
As shown in table 1 since among the embodiment 4～6 within the scope of the present invention according to the control of setovering of toner replenishing amount, so it is inhomogeneous that image does not take place, the toner that disperses is few, has suppressed toner and has dispersed.
Relative therewith since in comparative example 1 Vdc3=300V, therefore irrelevant and keep constant since initial stage bias voltage and toner replenishing amount, not according to the control of setovering of toner replenishing amount, so it is inhomogeneous to have produced image, toner disperses significantly.

Claims (21)

1. image processing system comprises in housing at least: the two-component developer supporting body at the internal configurations parts that are magnetic, keeps comprising the developer of carrier and toner by magnetic; And toner carrier, transfer toner from described two-component developer supporting body to self, carry toner thin layer from the teeth outwards; Apply developing bias to described toner carrier and/or described two-component developer supporting body, make the latent electrostatic image developing that forms on electrostatic latent image supporting body surface, described image processing system is characterised in that,
Compare with the approximated position of described two-component developer supporting body and described toner carrier, the toner that near the toner that disperses that is suspended in described toner carrier and the described two-component developer supporting body is reclaimed reclaims downstream one side that roller is configured in the sense of rotation of described two-component developer supporting body, and be configured between the wall of described two-component developer supporting body and described housing
And described image processing system comprises: bias unit, reclaim roller to described toner and apply and be used to reclaim the bias voltage of toner of dispersing; The image color detecting unit, to toner picture that is developed on the described electrostatic latent image supporting body surface or transfer printing the concentration of the toner picture on the transfer article of the toner picture that is developed on the described electrostatic latent image supporting body surface detect; And control module, use the testing result that obtains by described image color detecting unit control by described bias unit to described toner reclaim that roller applies, be used to reclaim the bias voltage of toner of dispersing.
2. image processing system as claimed in claim 1 is characterized in that,
Also comprise the bias difference setup unit of setting the bias difference Δ V between described two-component developer supporting body and the described toner carrier according to the toner concentration that detects by described image color detecting unit,
Described control module is controlled the described bias voltage that applies to described toner recovery roller according to the bias difference Δ V of described setting.
3. image processing system as claimed in claim 2 is characterized in that,
Control module carries out following control: be higher than at described toner concentration under the situation of normal concentration, after making described bias difference Δ V change, form the image patch once more and detect the concentration of this image patch, repeat said process and until becoming described normal concentration by described image color detecting unit.
4. image processing system as claimed in claim 3 is characterized in that,
Under the situation of described bias difference Δ V when becoming described normal concentration less than the threshold value of regulation, increase the described bias voltage that imposes on described toner recovery roller.
5. image processing system as claimed in claim 1 is characterized in that,
Also comprise: the surface potential detecting unit, detect the surface potential of described toner carrier; And toner carried charge computing unit, according to the surface potential of the described toner carrier that detects by described surface potential detecting unit and the toner concentration that detects by described image color detecting unit, calculate the toner carried charge of the toner thin layer on the described toner carrier;
Described control module is controlled according to this result of calculation and is imposed on the described bias voltage that described toner reclaims roller.
6. image processing system as claimed in claim 1 is characterized in that,
The peripheral speed of described electrostatic latent image supporting body is more than or equal to 180mm/sec.
7. image forming method, use is arranged on two-component developer supporting body and the toner carrier in the housing, apply developing bias to described toner carrier and/or described two-component developer supporting body, make the latent electrostatic image developing that on electrostatic latent image supporting body surface, forms, described two-component developer supporting body is at the internal configurations parts that are magnetic, the developer that keeps comprising carrier and toner by magnetic, described toner carrier is transferred toner from described two-component developer supporting body to self, carry toner thin layer from the teeth outwards, described image forming method is characterised in that
The testing result that use obtains by the image color detecting unit control by bias unit to toner reclaim that roller applies, be used to reclaim the bias voltage of toner of dispersing, described image color detecting unit be used for to toner picture that is developed on the described electrostatic latent image supporting body surface or transfer printing the concentration of the toner picture on the transfer article of the toner picture that is developed on the described electrostatic latent image supporting body surface detect
Compare with the approximated position of described two-component developer supporting body and described toner carrier, the described toner that near the toner that disperses that is suspended in described toner carrier and the described two-component developer supporting body is reclaimed reclaims roller and is configured in downstream one side of the sense of rotation of described two-component developer supporting body, and is configured between the wall of described two-component developer supporting body and described housing.
8. image forming method as claimed in claim 7 is characterized in that,
According to the toner concentration that detects by described image color detecting unit, set bias difference Δ V between described two-component developer supporting body and the described toner carrier for the thickness with the toner thin layer on the described toner carrier is maintained constant substantially, control to described toner according to the bias difference Δ V of described setting and reclaim the described bias voltage that roller applies.
9. image forming method as claimed in claim 8 is characterized in that,
Be higher than at described toner concentration under the situation of normal concentration, after making described bias difference Δ V change, form the image patch once more and detect the concentration of this image patch, repeat said process and until becoming described normal concentration by described image color detecting unit.
10. image forming method as claimed in claim 9 is characterized in that,
Under the situation of described bias difference Δ V when becoming described normal concentration less than the threshold value of regulation, increase the described bias voltage that imposes on described toner recovery roller.
11. image forming method as claimed in claim 7 is characterized in that,
According to the surface potential of the described toner carrier that detects by the surface potential detecting unit and the toner concentration that detects by described image color detecting unit, calculate the toner carried charge of the toner thin layer on the described toner carrier, control the described bias voltage that imposes on described toner recovery roller according to this result of calculation, wherein, described surface potential detecting unit detects the surface potential of the described toner carrier that is used to control described bias voltage.
12. an image processing system comprises in housing at least: the two-component developer supporting body at the internal configurations parts that are magnetic, keeps comprising the developer of carrier and toner by magnetic; And toner carrier, transfer toner from described two-component developer supporting body to self, carry toner thin layer from the teeth outwards; Apply developing bias to described toner carrier and/or described two-component developer supporting body, make the latent electrostatic image developing that forms on electrostatic latent image supporting body surface, described image processing system is characterised in that,
Compare with the approximated position of described two-component developer supporting body and described toner carrier, the toner that near the toner that disperses that is suspended in described toner carrier and the described two-component developer supporting body is reclaimed reclaims downstream one side that roller is configured in the sense of rotation of described two-component developer supporting body, and be configured between the wall of described two-component developer supporting body and described housing
And described image processing system comprises: bias unit, reclaim roller to described toner and apply and be used to reclaim the bias voltage of toner of dispersing; And control module, carry out following control, promptly, threshold amplitude to printing rate and regulation compares, under the situation of described printing rate, reclaim roller to described toner and apply the bias voltage that the alternating voltage DC voltage stack identical with the regular charged characteristic of developer with polarity forms greater than the higher limit of described threshold amplitude; Be positioned in described printing rate under the situation of scope of described threshold amplitude, reclaim roller to described toner and only apply alternating voltage; Under the situation of described printing rate, reclaim roller to described toner and apply the bias voltage that the alternating voltage DC voltage stack opposite with the regular charged characteristic of developer with polarity forms less than the lower limit of described threshold amplitude.
13. image processing system as claimed in claim 12 is characterized in that,
The peripheral speed of described electrostatic latent image supporting body is more than or equal to 180mm/sec.
14. image forming method, use is arranged on two-component developer supporting body and the toner carrier in the housing, apply developing bias to described toner carrier and/or described two-component developer supporting body, make the latent electrostatic image developing that on electrostatic latent image supporting body surface, forms, described two-component developer supporting body is at the internal configurations parts that are magnetic, the developer that keeps comprising carrier and toner by magnetic, described toner carrier is transferred toner from described two-component developer supporting body to self, carry toner thin layer from the teeth outwards, described image processing system is characterised in that
Threshold amplitude to printing rate and regulation compares, under the situation of described printing rate, reclaim roller to described toner and apply the bias voltage that the alternating voltage DC voltage stack identical with the regular charged characteristic of developer with polarity forms greater than the higher limit of described threshold amplitude; Be positioned in described printing rate under the situation of scope of described threshold amplitude, reclaim roller to described toner and only apply alternating voltage; Under the situation of described printing rate less than the lower limit of described threshold amplitude, reclaim roller to described toner and apply the bias voltage that the alternating voltage DC voltage stack opposite with the regular charged characteristic of developer with polarity forms,
Compare with the approximated position of described two-component developer supporting body and described toner carrier, the toner that near the described toner that disperses that is suspended in described toner carrier and the described two-component developer supporting body is reclaimed reclaims roller and is configured in downstream one side of the sense of rotation of described two-component developer supporting body, and is configured between the wall of described two-component developer supporting body and described housing.
15. image forming method as claimed in claim 14 is characterized in that,
The higher limit of described threshold amplitude is 7～20%, and the lower limit of described threshold amplitude is 1～10%.
16. an image processing system comprises in housing at least: the two-component developer supporting body at the internal configurations parts that are magnetic, keeps comprising the developer of carrier and toner by magnetic; And toner carrier, transfer toner by described two-component developer supporting body to self, carry toner thin layer from the teeth outwards; Apply developing bias to described toner carrier and/or described two-component developer supporting body, make the latent electrostatic image developing that forms on electrostatic latent image supporting body surface, described image processing system is characterised in that,
In described housing, be provided with the toner replenishing unit of the described toner of supply,
Compare with the approximated position of described two-component developer supporting body and described toner carrier, the electrod assembly that near the toner that disperses that is suspended in described toner carrier and the described two-component developer supporting body is reclaimed is configured in downstream one side of the sense of rotation of described two-component developer supporting body, and be configured between the wall of described two-component developer supporting body and described housing
And described image processing system comprises: bias unit applies to described electrod assembly and to be used to reclaim the bias voltage of toner of dispersing; And control module, control described bias voltage according to the toner replenishing amount of described toner replenishing unit.
17. image processing system as claimed in claim 16 is characterized in that,
Described toner replenishing unit comprises the toner quantity detection sensor, controls the toner replenishing amount according to the output valve of this toner quantity detection sensor.
18. image processing system as claimed in claim 16 is characterized in that,
Described electrod assembly is the rotation roller.
19. image processing system as claimed in claim 16 is characterized in that,
The peripheral speed of described electrostatic latent image supporting body is more than or equal to 180mm/sec.
20. image processing system as claimed in claim 17 is characterized in that,
Described control module carries out the control of described toner replenishing amount in the following manner: according to the output valve of toner quantity detection sensor, the toner replenishing roller that is arranged in the described toner replenishing unit is driven or stop to drive.
21. image processing system as claimed in claim 20 is characterized in that,
Under the situation of described toner replenishing amount, apply the DC voltage of forcing down than the direct current that imposes on described two-component developer supporting body to described electrod assembly more than or equal to setting.
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JP2007044408A JP5134829B2 (en) 2007-02-23 2007-02-23 Image forming apparatus and image forming method
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