JP2014089386A - Developer regulating member, developing device, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a high-quality image having less roughness, after a lapse of time in which a magnetic carrier is deteriorated, even when a developer regulating member in which a non-magnetic plate is disposed on a downstream side in a developer conveying direction with respect to a magnetic plate is used.SOLUTION: In a regulating blade 10 regulating the amount of a developer conveyed to a development area, in such a manner that a regulating end surface faces the surface of a developing sleeve 11 and the developer passes through between the surface of the developing sleeve and the regulating end surface, a magnetic plate 10b faces a non-magnetic plate 10a on an upstream side in the movement direction of the surface of the developing sleeve, so that the regulating end surface is formed of the end surface of the magnetic plate and the end surface of the non-magnetic plate, the end surface of the magnetic plate is more protruded to the side of the surface of the developing sleeve than the end surface of the non-magnetic plate, and the downstream end B of the end surface of the magnetic plate in the movement direction of the surface of a developer sleeve is closest to the surface of the developing sleeve.

Description

  The present invention relates to a developer regulating member that regulates the amount of developer conveyed to a developing area facing a latent image carrier, a developing device that includes the developer regulating member, and an image forming apparatus that includes the developing device. Is.

  2. Description of the Related Art Conventionally, there are a wide variety of developing devices that feed a developer into a developing region after the developer regulating member regulates the layer thickness of the developer carried by a magnetic force on the surface of a developer carrying member provided with a magnetic field generating means inside. Are known. In recent years, there is a tendency that the amount of developer fed into the development area is set to be small, and therefore it is required to regulate the developer layer thickness with a developer regulating member. Therefore, the tolerance of the gap (doctor gap) between the end surface (regulation end surface) facing the surface of the developer carrying member in the developer regulating member and the surface of the developer carrying member is very strict. Therefore, in order to widen this tolerance, a developing device in which a magnetic member is provided on the developer regulating member has been proposed.

The reason why the tolerance of the doctor gap can be widened by providing a magnetic member on the developer regulating member is as follows.
When the magnetic member is provided on the developer regulating member, the developer passing through the doctor gap is sparse compared to the case where the magnetic member is not provided on the developer regulating member. When a magnetic member is provided on the developer regulating member, a strong magnetic field is formed in and around the doctor gap by the magnetic member and the magnetic field generating means inside the developer carrying member. Stand up. The developer in the spiked state becomes a magnetic brush having a gap between the spikes, and is in a sparse state as compared to the case where the developer is not spiked without providing a magnetic member on the developer regulating member. If the developer is in a sparse state due to such spikes, the rate of change in the amount of developer passing therethrough with respect to the amount of change in the doctor gap is smaller than that in the dense state. Therefore, the tolerance of the doctor gap can be widened.

  As a developer regulating member provided with a magnetic member, those disclosed in Patent Document 1 and Patent Document 2 are known. The developer regulating member has a non-magnetic plate disposed on the downstream side in the developer transport direction with respect to a magnetic plate having a magnetic member as a plate.

  If the developer restricting member itself is composed of only a magnetic member, the tips of the magnetic brush due to the rising developer are collected on the developer restricting member, and the magnetic brush flutters when the tip of the magnetic brush moves away from the developer restricting member. . This fluttering deteriorates toner scattering. However, like the developer regulating member disclosed in Patent Documents 1 and 2, in the developer regulating member in which the non-magnetic plate is arranged on the downstream side in the developer transport direction with respect to the magnetic plate, for the following reason, Fluttering of the magnetic brush can be suppressed, and toner scattering can be suppressed.

  In the developer regulating member in which the non-magnetic plate is arranged on the downstream side in the developer conveying direction with respect to the magnetic plate, one end surface (magnetic plate end surface) of the magnetic plate facing the developer carrying member surface and one end surface of the non-magnetic plate The regulating end surface of the developer regulating member is formed with (nonmagnetic plate end surface). Even in such a developer regulating member, the tip of the magnetic brush due to the rising developer is collected on the magnetic plate, but when the tip of the magnetic brush leaves the magnetic plate, the magnetic brush flutters due to the presence of the non-magnetic plate. It is suppressed. This is presumably because when the tip of the magnetic brush is separated from the magnetic plate, the movement of the tip of the magnetic brush is hindered by the end face of the non-magnetic plate. Therefore, even when a developer restricting member provided with a magnetic member is used to widen the tolerance of the doctor gap, toner scattering is suppressed by disposing a non-magnetic plate downstream of the magnetic plate in the developer transport direction. It is possible.

  In the developing device disclosed in Patent Document 1, as shown in FIG. 13, the distance between the surface of the developer carrier and the end face of the magnetic plate is set larger than the distance between the surface of the developer carrier and the end face of the nonmagnetic plate. Has been. In such a configuration, the developer regulated between the surface of the developer carrier and the end surface of the magnetic plate is further regulated between the surface of the developer carrier and the end surface of the non-magnetic plate having a narrower interval thereafter. Will receive. In such a configuration, in order to set an appropriate amount of developer to be fed into the development area, it is required to manage the spacing between the surface of the developer carrier on both the magnetic plate and the nonmagnetic plate with high accuracy. The

  On the other hand, in the developing device disclosed in Patent Document 2, the end surface of the magnetic plate is protruded toward the surface of the developer carrying member rather than the end surface of the nonmagnetic plate to form a step on the regulating end surface of the developer regulating member. Thus, the distance between the surface of the developer carrying member and the end face of the magnetic plate is smaller than the distance between the surface of the developer carrying member and the end face of the nonmagnetic plate. Therefore, the developer restricted between the surface of the developer carrying member and the end face of the magnetic plate is not subjected to further restriction between the surface of the developer carrying member and the end face of the nonmagnetic plate. Therefore, if the distance between the surface of the developer carrying member and the end face of the magnetic plate is managed with high accuracy, the amount of developer fed into the development area can be set to an appropriate amount. In this configuration, high accuracy is not required for the distance between the surface of the developer carrying member and the end face of the nonmagnetic plate, so that the manufacturing cost can be reduced.

  However, as shown in FIGS. 14 and 15, in the developing device disclosed in Patent Document 2, the distance between the surface of the developer carrying member and the end surface of the magnetic plate is the narrowest at the upstream end in the developer transport direction, and the developer transport It gradually spreads downstream in the direction. As a result of research, the present inventors have found that with such a configuration, there is a problem that a feeling of vomit appears on the image over time when the deterioration of the magnetic carrier in the developer progresses. This sensation of feeling is caused by uneven image density having a period corresponding to the length in the developer conveyance direction on the end surface of the magnetic plate.

The present inventor examined the cause of such a feeling of vomit, and reached the following conclusion.
In the developing device disclosed in Patent Document 2, the point indicated by symbol A in FIGS. 14 and 15, that is, the upstream end of the magnetic plate end surface in the developer transport direction is closest to the surface of the developer carrying member. It is a point. Therefore, in this developing device, when the point A is passed, the regulation of the developer amount is completed.

  At the initial time when the deterioration of the magnetic carrier is not progressing, the magnetic carrier is appropriately magnetized, so that the tip of the magnetic brush is separated from the magnetic plate at the point A as shown in FIG. Therefore, at the initial stage, almost simultaneously with the completion of the regulation of the developer amount, the tip of the magnetic brush is separated from the end surface of the magnetic plate and is transported toward the developing region while being carried on the surface of the developer carrying member. . At this time, the phenomenon that the tip of the magnetic brush is separated from the end face of the magnetic plate continuously occurs without taking time. Therefore, it is possible to make the developer amount per unit area of the developer passing through the point A per unit area substantially uniform.

  On the other hand, with the lapse of time when the deterioration of the magnetic carrier has progressed, the magnetic carrier coat layer is peeled off, and the magnetic carrier is easily magnetized excessively. Therefore, the tip of the magnetic brush is not separated from the end face of the magnetic plate at the point A and remains adsorbed on the end face of the magnetic plate. Then, the magnetic brush is pulled by the developer carrier that moves on the surface, and is pushed by the developer passing through the point A later, so that the developer is conveyed while the tip is adsorbed to the magnetic plate. Move downstream in the direction. Then, as shown in FIG. 15, the tip of the magnetic brush is separated from the end surface of the magnetic plate when it reaches the point indicated by B in the drawing, that is, the downstream end in the developer transport direction of the end surface of the magnetic plate. At this time, if the tip of the magnetic brush is separated from the end surface of the magnetic plate at the point B, due to the effect of a sudden change in the magnetic field, impact, and increased cohesive force due to developer deterioration, the upstream side in the developer transport direction. The magnetic brush adsorbed on the end face of the magnetic plate is also separated from the end face of the magnetic plate together. As a result, the magnetic brush adsorbed over the entire area of the magnetic plate end face is separated from the magnetic plate end face at once. As a result, a lump of developer that is separated from the end surface of the magnetic plate at a time is carried on the surface of the developer carrying member and conveyed toward the developing region in that state.

  When the magnetic brush adsorbed over the entire area of the end face of the magnetic plate is separated from the magnetic plate at once, the entire area of the end face of the magnetic plate is not in contact with the magnetic brush. With respect to the end surface of the magnetic plate, the developer magnetic brush conveyed later passes again through the point A, and is successively conveyed downstream in the developer conveying direction, with its tip adsorbed to the end surface of the magnetic plate. The Then, when the tip of the leading magnetic brush is separated from the end surface of the magnetic plate at the point B, the developer lump is conveyed again toward the developing region while being held on the surface of the developer carrier. The developer lump formed by repeating such a phenomenon is carried on the surface of the developer carrying member at an interval corresponding to the length in the developer conveying direction on the end surface of the magnetic plate, and is transferred to the developing region. Will be sent. As a result, image density unevenness having a period corresponding to the length in the developer conveyance direction on the end surface of the magnetic plate occurs.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a magnetic carrier even when using a developer regulating member in which a non-magnetic plate is disposed downstream of the magnetic plate in the developer transport direction. It is an object to provide a developer regulating member, a developing device, and an image forming apparatus that are capable of forming a high-quality image with little vomit feeling over time.

  In order to achieve the above object, the present invention is composed of a magnetic plate and a nonmagnetic plate disposed on the downstream side in the developer transport movement direction by the developer carrier of the magnetic plate, from the end surface of the nonmagnetic plate. In the developer regulating member in which the end surface of the magnetic plate protrudes on the surface of the developer carrier, the downstream end of the magnetic plate in the developer transport direction is closest to the surface of the developer carrier. It is characterized by being.

  The regulation of the developer amount is completed at the place where the distance is the narrowest between the developer carrier surface and the end face of the magnetic plate. Therefore, in the present invention, the restriction of the developer amount is completed at the downstream end of the magnetic plate end surface in the developer transport direction. In the present invention, since the end face of the magnetic plate protrudes to the surface side of the developer carrying member from the end face of the non-magnetic plate, the tip of the magnetic brush passes when passing through the downstream end in the developer transport direction of the end face of the magnetic plate. Will leave the magnetic plate. Such a phenomenon is stable regardless of the progress of the deterioration of the magnetic carrier. Therefore, even when the deterioration of the magnetic carrier progresses, the point where the tip of the magnetic brush is separated from the magnetic plate is stabilized at the downstream end of the magnetic plate end surface in the developer transport direction. In this way, the phenomenon that the tip of the magnetic brush is separated from the end face of the magnetic plate at the downstream end of the developer conveying direction of the end face of the magnetic plate where the regulation of the developer amount is completed, takes time. It occurs continuously without. Therefore, the developer amount per unit area on the surface of the developer carrying member conveyed to the development area is almost uniform not only in the initial stage where the deterioration of the magnetic carrier has progressed but also in the time when the deterioration of the magnetic carrier has progressed. It is possible to

  As described above, according to the present invention, even when a developer regulating member in which a nonmagnetic plate is disposed on the downstream side in the developer conveyance direction with respect to the magnetic plate is used, a high quality with less vomit feeling over time when the magnetic carrier is deteriorated. An excellent effect that an image can be formed is obtained.

1 is a schematic configuration diagram of a copier according to an embodiment. FIG. 2 is a cross-sectional view illustrating a schematic configuration of a developing device in the copier. It is sectional drawing of the collection conveyance path and the stirring conveyance path in the conveyance direction downstream part of a collection conveyance path. It is sectional drawing in the conveyance direction upstream part of the supply conveyance path of the developing device. It is sectional drawing in the conveyance direction downstream part of the supply conveyance path of the developing device. It is a schematic diagram of the flow of the developer in the developing device. It is sectional drawing in the conveyance direction most downstream part of the supply conveyance path of the developing device. FIG. 3 is a cross-sectional view of a schematic configuration of a regulating blade of the developing device cut in a direction orthogonal to a developing sleeve rotation axis direction. FIG. 5 is an enlarged view of a facing region between the regulation blade and the developing sleeve. It is a table | surface which shows the result of an effect confirmation test. FIG. 6 is a cross-sectional view showing a schematic configuration of a regulating blade in a configuration of a comparative example used in the same effect confirmation test, cut in a direction orthogonal to a developing sleeve rotation axis direction. It is an enlarged view of the opposing area | region of the control blade and developing sleeve of a comparative example. FIG. 7 is an explanatory diagram showing a conventional configuration in which the distance between the surface of the developer carrier and the end face of the magnetic plate is set larger than the distance between the surface of the developer carrier and the end face of the nonmagnetic plate. In the conventional configuration in which the distance between the surface of the developer carrier and the end surface of the magnetic plate is set smaller than the distance between the surface of the developer carrier and the end surface of the nonmagnetic plate, the state of the magnetic brush at the initial stage is schematically shown. It is explanatory drawing. An explanation schematically showing the state of the magnetic brush over time in the conventional configuration in which the distance between the surface of the developer carrier and the end face of the magnetic plate is set smaller than the distance between the surface of the developer carrier and the end face of the nonmagnetic plate FIG.

Hereinafter, as an image forming apparatus to which the present invention is applied, an embodiment of a tandem type copying machine (hereinafter simply referred to as “copying machine”) in which a plurality of photoconductors are arranged in parallel will be described.
FIG. 1 is a schematic configuration diagram of a copying machine according to the present embodiment.
The copying machine includes a printer unit 100, a paper feeding device 200 on which the printer unit 100 is placed, a scanner 300 fixed on the printer unit 100, and the like. An automatic document feeder 400 fixed on the scanner 300 is also provided.

  The printer unit 100 forms an image including four sets of process cartridges 18Y, 18M, 18C, and 18K for forming an image of each color of yellow (Y), magenta (M), cyan (C), and black (K). A unit 20 is provided. Y, M, C, and K added after the numerals are the members for yellow, cyan, magenta, and black (the same applies hereinafter). In addition to the process cartridges 18Y, 18M, 18C, and 18K, an optical writing unit 21, an intermediate transfer unit 17, a secondary transfer device 22, a resist roller pair 49, a belt fixing type fixing device 25, and the like are disposed. .

  The optical writing unit 21 includes a light source (not shown), a polygon mirror, an f-θ lens, a reflection mirror, and the like, and irradiates the surface of a photoreceptor to be described later with laser light based on image data.

  The process cartridges 18Y, 18M, 18C, and 18K include a drum-shaped photosensitive member 1, a charger, a developing device 4, a drum cleaning device, a static eliminator, and the like.

Hereinafter, the yellow process cartridge 18 will be described.
The surface of the photoreceptor 1Y is uniformly charged by a charger as charging means. The surface of the photoreceptor 1 </ b> Y that has been subjected to charging processing is irradiated with laser light that has been modulated and deflected by the optical writing unit 21. Then, the potential of the irradiation part (exposure part) is attenuated. By this attenuation, an electrostatic latent image for Y is formed on the surface of the photoreceptor 1Y. The formed electrostatic latent image for Y is developed by the developing device 4Y as developing means to become a Y toner image. The Y toner image formed on the Y photoconductor 1Y is primarily transferred to an intermediate transfer belt 110 described later. The surface of the photoreceptor 1Y after the primary transfer is cleaned of the transfer residual toner by a drum cleaning device. In the Y process cartridge 18Y, the photoconductor 1Y cleaned by the drum cleaning device is discharged by the charge eliminator. Then, it is uniformly charged by the charger and returns to the initial state. The series of processes as described above is the same for the other process cartridges 18M, 18C, and 18K.

Next, the intermediate transfer unit will be described.
The intermediate transfer unit 17 includes an intermediate transfer belt 110, a belt cleaning device 90, and the like. Further, it also includes a tension roller 14, a driving roller 15, a secondary transfer backup roller 16, four primary transfer bias rollers 62Y, 62M, 62C, and 62K. The intermediate transfer belt 110 is tensioned by a plurality of rollers including the tension roller 14. Then, it is endlessly moved clockwise in the drawing by the rotation of the driving roller 15 driven by a belt driving motor (not shown).

  The four primary transfer bias rollers 62Y, 62M, 62C, and 62K are arranged so as to be in contact with the inner peripheral surface side of the intermediate transfer belt 110, respectively, and receive a primary transfer bias from a power source (not shown). Further, the intermediate transfer belt 110 is pressed toward the photoreceptors 1Y, 1M, 1C, and 1K from the inner peripheral surface side to form primary transfer nips. In each primary transfer nip, a primary transfer electric field is formed between the photosensitive member and the primary transfer bias roller due to the influence of the primary transfer bias. The above-described Y toner image formed on the Y photoconductor 1Y is primarily transferred onto the intermediate transfer belt 110 due to the influence of the primary transfer electric field and nip pressure. On the Y toner image, the M, C, and K toner images formed on the M, C, and K photoconductors 1M, 1C, and 1K are sequentially superimposed and primarily transferred. By this primary transfer of superposition, a four-color superposed toner image (hereinafter referred to as “four-color toner image”) as a multiple toner image is formed on the intermediate transfer belt 110.

  The four-color toner image superimposed and transferred onto the intermediate transfer belt 110 is secondarily transferred onto a transfer sheet (not shown) as a recording sheet at a secondary transfer nip described later. Transfer residual toner remaining on the surface of the intermediate transfer belt 110 after passing through the secondary transfer nip is cleaned by a belt cleaning device 90 that sandwiches the belt with the driving roller 15 on the left side in the drawing.

Next, the secondary transfer device 22 will be described.
Below the intermediate transfer unit 17 in the figure, a secondary transfer device 22 is disposed in which a paper conveying belt 24 is stretched by two stretching rollers 23. The paper transport belt 24 is moved endlessly in the counterclockwise direction in the drawing in accordance with the rotational drive of at least one of the stretching rollers 23. One of the two stretching rollers 23 arranged on the right side in the drawing sandwiches the intermediate transfer belt 110 and the paper transport belt 24 between the secondary transfer backup roller 16 of the intermediate transfer unit 17. It is out. By this sandwiching, a secondary transfer nip is formed in which the intermediate transfer belt 110 of the intermediate transfer unit 17 and the paper transport belt 24 of the secondary transfer device 22 are in contact with each other. A secondary transfer bias having a polarity opposite to that of the toner is applied to the one stretching roller 23 by a power source (not shown). By applying this secondary transfer bias, the four-color toner image on the intermediate transfer belt 110 of the intermediate transfer unit 17 is electrostatically moved from the belt side toward the one stretching roller 23 side in the secondary transfer nip. A next transfer electric field is formed. The transfer paper fed into the secondary transfer nip so as to synchronize with the four-color toner image on the intermediate transfer belt 110 by a registration roller pair 49 to be described later has four colors affected by the secondary transfer electric field and nip pressure. The toner image is secondarily transferred. Instead of the secondary transfer method in which the secondary transfer bias is applied to one of the stretching rollers 23 as described above, a charger for charging the transfer paper in a non-contact manner may be provided.

  In the paper feeding device 200 provided at the lower part of the copying machine main body, a plurality of paper feeding cassettes 44 in which a plurality of transfer sheets can be stacked and accommodated in a bundle of sheets are arranged so as to overlap in the vertical direction. Has been. Each paper feed cassette 44 presses the paper feed roller 42 against the uppermost transfer paper in the paper bundle. Then, by rotating the paper feed roller 42, the uppermost transfer paper is sent out toward the paper feed path 46.

  The paper feed path 46 that receives the transfer paper fed from the paper feed cassette 44 has a plurality of conveying roller pairs 47 and a registration roller pair 49 provided near the end in the path. Then, the transfer paper is conveyed toward the registration roller pair 49. The transfer sheet conveyed toward the registration roller pair 49 is sandwiched between the rollers of the registration roller pair 49. On the other hand, in the intermediate transfer unit 17, the four-color toner image formed on the intermediate transfer belt 110 enters the secondary transfer nip as the belt moves endlessly. The registration roller pair 49 sends out the transfer paper sandwiched between the rollers at a timing at which the transfer paper can be brought into close contact with the four-color toner image at the secondary transfer nip. Thereby, in the secondary transfer nip, the four-color toner image on the intermediate transfer belt 110 is in close contact with the transfer paper. Then, it is secondarily transferred onto the transfer paper and becomes a full color image on the white transfer paper. The transfer paper on which the full-color image is formed in this manner exits the secondary transfer nip as the paper transport belt 24 moves endlessly, and then is sent from the paper transport belt 24 to the fixing device 25.

  The fixing device 25 includes a belt unit that moves the fixing belt 26 endlessly while being stretched by two rollers, and a pressure roller 27 that is pressed toward one roller of the belt unit. The fixing belt 26 and the pressure roller 27 are in contact with each other to form a fixing nip, and the transfer paper received from the paper transport belt 24 is sandwiched therebetween. Of the two rollers in the belt unit, the roller that is pressed from the pressure roller 27 has a heat source (not shown) inside, and pressurizes the fixing belt 26 by the generated heat. The pressed fixing belt 26 heats the transfer paper sandwiched in the fixing nip. The full color image is fixed on the transfer paper by the influence of the heating and the nip pressure.

  The transfer paper that has been subjected to the fixing process in the fixing device 25 is stacked on a stack portion 57 that protrudes from the left side plate in the drawing of the printer housing or forms a toner image on the other surface. Therefore, it is returned to the secondary transfer nip described above.

  When a document (not shown) is copied, for example, a bundle of sheet documents is set on the document table 30 of the automatic document feeder 400. However, when the original is a single-sided original that is closed in a main form, it is set on the contact glass 32. Prior to this setting, the automatic document feeder 400 is opened with respect to the copying machine main body, and the contact glass 32 of the scanner 300 is exposed. Thereafter, the single-bound original is pressed by the closed automatic document feeder 400.

  When a copy start switch (not shown) is pressed after the document is set in this way, the document reading operation by the scanner 300 starts. However, when a sheet document is set on the automatic document feeder 400, the automatic document feeder 400 automatically moves the sheet document to the contact glass 32 prior to the document reading operation. In the document reading operation, first, the first traveling body 33 and the second traveling body 34 start traveling together, and light is emitted from a light source provided in the first traveling body 33. Then, the reflected light from the document surface is reflected by a mirror provided in the second traveling body 34, passes through the imaging lens 35, and then enters the reading sensor 36. The reading sensor 36 constructs image information based on the incident light.

  In parallel with such document reading operation, each device in each of the process cartridges 18Y, 18M, 18C, and 18K, the intermediate transfer unit 17, the secondary transfer device 22, and the fixing device 25 start driving. Based on the image information constructed by the reading sensor 36, the optical writing unit 21 is driven and controlled, and Y, M, C, and K toner images are formed on the photoreceptors 1Y, 1M, 1C, and 1K. Is done. These toner images become four-color toner images superimposed and transferred on the intermediate transfer belt 110.

  Further, almost simultaneously with the start of the document reading operation, the paper feeding operation is started in the paper feeding device 200. In this paper feeding operation, one of the paper feeding rollers 42 is selectively rotated, and the transfer paper is sent out from one of the paper feeding cassettes 44 accommodated in the paper bank 43 in multiple stages. The fed transfer sheets are separated one by one by the separation roller 45 and enter the reverse feeding path 46, and then conveyed toward the secondary transfer nip by the conveyance roller pair 47. In some cases, paper feeding from the manual feed tray 51 is performed instead of such paper feeding from the paper feeding cassette 44. In this case, after the manual feed roller 50 is selectively rotated to feed the transfer paper on the manual feed tray 51, the separation roller 52 separates the transfer paper one by one and feeds it to the manual feed path 53 of the printer unit 100. Make paper.

  In the case of forming a multi-color image composed of two or more colors of toner, the copying machine stretches the intermediate transfer belt 110 so that the upper stretched surface is almost horizontal, Photoconductors 1Y, 1M, 1C, and 1K. On the other hand, when forming a monochrome image consisting of only K toner, the intermediate transfer belt 110 is tilted to the lower left in the drawing by a mechanism (not shown) and the upper stretched surface is set to Y, M, C. The photoconductors 1Y, 1M, and 1C are separated. Of the four photoconductors 1Y, 1M, 1C, and 1K, only the K photoconductor 1K is rotated counterclockwise in the drawing to form only the K toner image. At this time, for Y, M, and C, not only the photosensitive member but also the developing device is stopped to prevent unnecessary consumption of the photosensitive member and the developer.

  The copying machine includes a control unit (not shown) configured by a CPU or the like that controls the following devices in the copying machine, and an operation display unit (not shown) configured by a liquid crystal display, various key buttons, and the like. The operator sends a command to the control unit by a key input operation on the operation display unit, so that one of the three modes is selected from the three-sided print mode, which is a mode for forming an image only on one side of the transfer paper. You can choose one. The three single-sided printing modes include a direct discharge mode, a reverse discharge mode, and a reverse decal discharge mode.

FIG. 2 is an enlarged configuration diagram showing the developing device 4 and the photosensitive member 1 included in one of the four process cartridges 18Y, 18M, 18C, and 18K.
The four process cartridges 18Y, 18M, 18C, and 18K have substantially the same configuration except that they handle different colors of toner. Therefore, the subscripts Y, M, C, and K are omitted in FIG. Yes.

  The developing device 4 of this embodiment includes a developing container 2 containing a two-component developer, and a developing sleeve 11 as a developer carrying member is connected to the photosensitive member 1 at an opening of the developing container 2 facing the photosensitive member 1. It is installed rotatably at a predetermined interval. The developing sleeve 11 is made of a non-magnetic cylindrical material and rotates in a direction in which the facing portion moves in the same direction with respect to the photosensitive member 1 rotating in the direction of the arrow. Inside the developing sleeve 11, a magnet roller for magnetic field generating means is fixedly arranged. The magnet roller has five magnetic poles N1, S1, N2, N3, and S2. A regulating blade 10 as a developer regulating member is attached to the portion of the developing container 2 above the developing sleeve 11, and this regulating blade 10 is directed toward the vicinity of the magnetic pole S <b> 2 that is substantially positioned at the uppermost point in the vertical direction of the magnet roller. The developing sleeve 11 is disposed in a non-contact manner.

  In the developing container 2, a supply screw 5 serving as a first developer stirring and conveying unit, a recovery screw 6 serving as a second developer stirring and conveying unit, and a stirring screw 7 serving as a third developer stirring and conveying unit are accommodated. There are provided three developer transport paths: a path 2a, a recovery transport path 2b, and a stirring transport path 2c. The supply conveyance path 2a and the agitation conveyance path 2c are arranged obliquely in the vertical direction. Further, the collection conveyance path 2b is disposed on the downstream side of the developing region of the developing sleeve 11 and on a side substantially horizontal to the stirring conveyance path 2c.

  The two-component developer accommodated in the developing container 2 is circulated and conveyed through the supply conveyance path 2a, the collection conveyance path 2b, and the agitation conveyance path 2c by stirring and conveyance of the supply screw 5, the recovery screw 6 and the stirring screw 7, The toner is supplied to the developing sleeve 11 from the supply conveyance path 2a. The developer supplied to the developing sleeve 11 is pumped onto the developing sleeve 11 by the magnetic pole N2 of the magnet roller. As the developing sleeve 11 rotates, the developing sleeve 11 is conveyed from the magnetic pole S2 to the magnetic pole N1, and from the magnetic pole N1 to the magnetic pole S1, and reaches the developing area where the developing sleeve 11 and the photosensitive member 1 face each other. In the course of the conveyance, the developer is magnetically regulated by the regulating blade 10 in cooperation with the magnetic pole S2, and a thin layer of developer is formed on the developing sleeve 11. The magnetic pole S1 of the magnet roller located in the developing area in the developing sleeve 11 is the developing main pole, and the developer conveyed to the developing area rises by the magnetic pole S1 and comes into contact with the surface of the photosensitive member 1 to be photosensitive. The electrostatic latent image formed on the surface of the body 1 is developed. The developer that has developed the latent image passes through the developing region as the developing sleeve 11 rotates, returns to the developing container 2 through the transport pole N3, and is separated from the developing sleeve 11 by the repulsive magnetic field of the magnetic poles N2 and N3. It is collected in the collection conveyance path 2b by the collection screw 6.

  The supply conveyance path 2a and the collection conveyance path 2b obliquely below are partitioned by the first partition member 3A.

  The collection conveyance path 2b and the agitating conveyance path 2c arranged on the side are partitioned by the second partition member 3B, but the collected developer is disposed downstream in the conveyance direction by the collection screw 6 of the collection conveyance path 2b. Is provided with a developer supply opening for supplying the toner to the agitating and conveying path 2c. FIG. 3 is a cross-sectional view of the collection conveyance path 2b and the agitation conveyance path 2c at the downstream portion in the conveyance direction by the collection screw 6, and an opening 2d that connects the collection conveyance path 2b and the agitation conveyance path 2c is provided. .

  Further, the supply conveyance path 2a and the stirring conveyance path 2c arranged obliquely below are partitioned by the third partition member 3C, but in the upstream and downstream parts in the conveyance direction by the supply screw 5 of the supply conveyance path 2a, A developer supply opening for supplying the developer is provided. FIG. 4 is a cross-sectional view of the developing device 4 at the upstream portion in the conveyance direction by the supply screw 5, and an opening 2 e that communicates the agitation conveyance path 2 c and the supply conveyance path 2 a is provided in the third partition member 3 C. FIG. 5 is a cross-sectional view of the developing device 4 at the downstream portion in the conveyance direction by the supply screw 5. The third partition member 3 </ b> C is provided with an opening 2 f that connects the agitation conveyance path 2 c and the supply conveyance path 2 a. Yes.

Next, the circulation of the developer in the three developer conveyance paths will be described.
FIG. 6 is a schematic diagram of the developer flow in the developing device 4. Each arrow in FIG. 6 indicates the moving direction of the developer. In the supply conveyance path 2 a that receives the developer supplied from the agitation conveyance path 2 c, the developer is conveyed downstream in the conveyance direction of the supply screw 5 while supplying the developer to the developing sleeve 11. The surplus developer conveyed to the downstream side in the conveyance direction of the supply conveyance path 2a without being supplied to the development sleeve 11 is from an opening 2f as a first developer supply opening provided in the third partition member 3C. It is supplied to the agitation transport path 2c.

  The recovered developer recovered from the developing sleeve 11 to the recovery transport path 2b by the recovery screw 6 and transported to the downstream portion in the transport direction in the same direction as the developer in the supply transport path 2a is provided in the second partition member 3B. The developer is supplied to the stirring and conveying path 2c from the opening 2d as the second developer supply opening.

  In the agitating and conveying path 2c, the surplus developer and the recovered developer supplied by the agitating screw 7 are agitated and conveyed in the opposite direction to the developer in the collecting and conveying path 2b and the supplying and conveying path 2a. The developer conveyed downstream in the conveyance direction of the agitation conveyance path 2c is upstream in the conveyance direction of the supply conveyance path 2a from the opening 2e serving as the third developer supply opening provided in the third partition member 3C. Supplied to the department.

  A toner concentration sensor (not shown) is provided below the agitation transport path 2c, and a toner supply control device (not shown) is operated by the sensor output to supply toner from a toner container (not shown). . In the agitating and conveying path 2c, the toner replenished from the toner replenishing port 3 as necessary is conveyed by the agitating screw 7 to the downstream side in the conveying direction while being agitated with the collected developer and the surplus developer. When replenishing toner, replenishing upstream of the agitation screw 7 can increase the agitation time from replenishment to development.

  As described above, the developing device 4 includes the supply conveyance path 2a and the collection conveyance path 2b, and the developer supply and collection are performed in different developer conveyance paths, so that the developed developer is mixed into the supply conveyance path 2a. There is nothing to do. Therefore, it is possible to prevent the toner concentration of the developer supplied to the developing sleeve 11 from decreasing toward the downstream side of the supply conveyance path 2a in the conveyance direction. Further, since the recovery conveyance path 2b and the agitation conveyance path 2c are provided and the developer is collected and stirred in different developer conveyance paths, the developed developer does not fall during the agitation. Therefore, since the sufficiently stirred developer is supplied to the supply conveyance path 2a, it is possible to prevent the developer supplied to the supply conveyance path 2a from being insufficiently stirred. In this way, the toner density of the developer in the supply conveyance path 2a can be prevented from decreasing, and the developer in the supply conveyance path 2a can be prevented from being insufficiently stirred, so the image density during development can be reduced. Can be constant.

  Further, in the upstream portion in the conveyance direction of the supply conveyance path 2a shown in FIG. 4, the developer is supplied from the stirring conveyance path 2c disposed obliquely downward to the upper supply conveyance path 2a. In the delivery of the developer, the developer is pushed up by the rotation of the stirring screw 7 so that the developer is raised and overflows from the opening 2e to supply the developer to the supply conveyance path 2a. Such movement of the developer gives stress to the developer and contributes to a decrease in the life of the developer. In the developing device 4, the supply conveyance path 2a is arranged so as to be obliquely above the agitation conveyance path 2c, so that the supply conveyance path 2a is provided vertically above the agitation conveyance path 2c, and the developer is lifted, It is possible to reduce the developer stress in the upward movement of the developer.

  Further, in the downstream portion in the conveyance direction by the supply screw 5 shown in FIG. 5, in order to supply the developer from the supply conveyance path 2a disposed above to the stirring conveyance path 2c disposed obliquely below, the supply conveyance path 2a An opening 2f that communicates with the stirring and conveying path 2c is provided. Here, the 3rd partition member 3C which partitions the stirring conveyance path 2c and the supply conveyance path 2a is extended upwards from the lowest point of the supply conveyance path 2a, and the opening part 2f is a position above the lowest point. Is provided. FIG. 7 is a cross-sectional view of the developing device 4 at the most downstream portion in the conveyance direction by the supply screw 5. As shown in FIG. 7, an opening 2g is provided downstream of the opening 2f in the conveyance direction by the supply screw 5 so as to communicate the stirring conveyance path 2c and the supply conveyance path 2a with the third partition member 3C. Yes. The opening 2g is provided above the top of the opening 2f.

  In the supply conveyance path 2a having the openings 2f and 2g, the bulk of the developer conveyed in the axial direction through the supply conveyance path 2a to the opening 2f by the supply screw 5 reaches the lowest height of the opening 2f. Things fall down to the lower stirring conveyance path 2c through the opening 2f. On the other hand, the developer that does not reach the lowest height of the opening 2 f is supplied to the developing sleeve 11 while being conveyed further downstream by the supply screw 5. Therefore, on the downstream side of the opening 2f in the supply conveyance path 2a, the bulk of the developer gradually becomes lower than the lowest part of the opening 2f. Since the most downstream portion of the supply conveyance path 2a is a dead end, the bulk of the developer may increase in the most downstream portion. However, when the height reaches a certain level, the developer is pushed back against the supply screw 5 and opened. What returns to the part 2f and reaches the lowest height of the opening 2f spills down to the lower agitating and conveying path 2c through the opening 2f. Thus, on the downstream side of the opening 2f of the supply conveyance path 2a, the bulk of the developer does not continue to increase, and an equilibrium state with a gradient near the bottom of the opening 2f is obtained. By providing the opening 2g at a position higher than the uppermost part of the opening 2f, that is, a position higher than this equilibrium state, there is little possibility that the opening 2f is blocked by the developer and the ventilation becomes insufficient. Sufficient ventilation can be ensured by the stirring conveyance path 2c and the supply conveyance path 2a. That is, the opening 2g does not function as a developer supply opening between the supply conveyance path 2a and the agitation conveyance path 2c, and ensures sufficient ventilation between the supply conveyance path 2a and the agitation conveyance path 2c. It fulfills the function as an opening for ventilation. By providing such an opening 2g for ventilation, a filter that allows air to pass therethrough is provided even if the internal pressure rises in the agitation conveyance path 2c disposed below and the recovery conveyance path 2b communicating with the agitation conveyance path 2c. Further, it is possible to ensure sufficient ventilation with the upper supply conveyance path 2a, and it is possible to suppress an increase in internal pressure of the entire developing device 4.

Next, the regulating blade 10 that is a characteristic part of the present invention will be described.
Since the same regulating blade is used in any color developing device, the following description will be made with the color-coded symbols Y, C, M, and K omitted.
FIG. 8 is a cross-sectional view of the schematic configuration of the regulating blade 10 in the present embodiment cut in a direction orthogonal to the rotation axis direction of the developing sleeve 11.
The regulating blade 10 of the present embodiment has a configuration in which a magnetic plate 10b is disposed opposite to the nonmagnetic plate 10a, which is a blade body, on the upstream side of the developing sleeve surface movement direction. In the restriction blade 10, a restriction end face is formed by an end face of the magnetic plate that is one end face (lower face in the figure) of the magnetic plate 10b and an end face of the nonmagnetic board that is one end face (lower face in the figure) of the nonmagnetic plate 10a. The

  For the nonmagnetic plate 10a, for example, a plate-like member made of SUS304 having a thickness of about 2 mm can be used. As the magnetic plate 10b, for example, a plate-like member made of SUS430 having a plate thickness of about 0.3 mm can be used. The magnetic plate 10b is fastened to the nonmagnetic plate 10a by caulking a half-clamped crimped portion 10c made of a nonmagnetic material. The nonmagnetic plate 10a is attached to the developing container 2 with screws 10d.

  The nonmagnetic plate 10a can be formed by extracting the outer shape by press working. At this time, a surface on which burrs are generated (hereinafter referred to as “burr surface”) and a surface on which the corners sag due to the outer shape (hereinafter referred to as “sag surface”) are generated. In the present embodiment, the magnetic plate 10b is fixed to the sag surface side of the nonmagnetic plate 10a. In this case, even if the polishing process is performed, a groove due to the sagging of the non-magnetic plate 10a exists on the regulation end surface of the regulation blade 10, and toner and other foreign matters in the developer accumulate in the groove. May grow. However, in this embodiment, since the end surface of the magnetic plate 10b is configured to protrude from the end surface of the non-magnetic plate 10a, there is little adverse effect of the grown deposit. On the other hand, the magnetic plate 10b may be fixed to the burr surface side of the nonmagnetic plate 10a.

  Similarly to the non-magnetic plate 10a, the magnetic plate 10b can also be formed by extracting the outer shape by pressing. In this case, the developing plate surface downstream direction end B of the magnetic plate end surface may be either a burr surface end or a sag surface end.

  In the present embodiment, the end surface of the magnetic plate 10b of the regulating blade 10 protrudes to the surface side of the developing sleeve 11 from the end surface of the nonmagnetic plate 10a. The protrusion amount is preferably in the range of 0.2 [mm] to 0.5 [mm], for example. If the amount of protrusion exceeds 0.5 [mm], the effect of suppressing the flapping of the magnetic brush by the non-magnetic plate 10a arranged on the downstream side of the magnetic sleeve 10b in the direction of movement of the developing sleeve cannot be obtained sufficiently, and toner scattering occurs. It is easy to get worse. On the other hand, when the protruding amount is shorter than 0.2 [mm], the distance between the nonmagnetic plate 10a and the developing sleeve 11 tends to affect the amount of developer regulated by the regulating blade 10, and the nonmagnetic plate 10a. Highly accurate management is also required for the distance between the developing sleeve 11 and the developing sleeve 11.

The developer carried on the surface of the developing sleeve 11 and conveyed along with the movement of the surface of the developing sleeve is raised in the vicinity of the opposing area between the magnetic plate 10b and the developing sleeve 11 by a magnetic field by a magnet roller, and a magnetic brush is applied. Form. When the amount of developer is regulated to about 0.35 [mg / cm ² ] by the regulating blade 10, for example, the distance between the magnetic plate 10b and the developing sleeve 11 is the same as that of a conventional regulating blade using a magnetic member. Set to

FIG. 9 is an enlarged view of a facing region between the regulating blade 10 and the developing sleeve 11 in the present embodiment.
In the present embodiment, of the magnetic plate end surface (lower surface in the drawing) of the magnetic plate 10 b, the downstream end in the developing sleeve surface moving direction is the nearest ground point B closest to the surface of the developing sleeve 11. Therefore, the regulation of the developer amount by the regulation blade 10 in this embodiment is completed when the developer passes through the downstream end B in the developing sleeve surface movement direction of the magnetic plate end face.

  Here, in FIG. 9, when a normal line C on the surface of the developing sleeve 11 is drawn so as to pass through the latest ground point B, a point on the surface of the developing sleeve 11 through which the normal line C passes is defined as B ′. . A tangent to the surface of the developing sleeve 11 at this point B ′ is indicated by the symbol D. When an imaginary line D ′ parallel to the tangent line D and passing through the grounding point B is drawn, an angle θ1 formed by the imaginary line D ′ and the end surface of the magnetic plate 10b is greater than 0 °. (In FIG. 9, the angle in the counterclockwise direction from the imaginary line D ′ is positive). However, in this embodiment, the angle is close to 0 °. As the angle θ1 approaches 0 °, the magnetic force gradually changes from the upstream side of the developing sleeve surface moving direction toward the downstream end, which is the closest ground point B, on the end surface of the magnetic plate 10b. Therefore, while the developer moves from the upstream side to the downstream side in the direction of movement of the developing sleeve on the end surface of the magnetic plate, the magnetic brush is properly maintained, and stable regulation of the developer amount can be realized.

  In this embodiment, the angle θ2 formed by the virtual line D ′ and the plate surface on the downstream side in the moving direction of the developing sleeve of the magnetic plate 10b (the plate surface facing the nonmagnetic plate 10a) is as large as possible. Specifically, an angle of about 90 ° is desirable. The larger the angle θ2, the more rapidly the magnetic field becomes smaller on the downstream side of the closest contact point B in the direction of movement of the developing sleeve surface. As a result, the tip of the magnetic brush that has been attracted to the end face of the magnetic plate up to the nearest ground point B can be stably separated from the end face of the magnetic plate at the nearest ground point B.

  In this embodiment, when the developer passes through the magnetic plate end surface (the lower surface in the drawing) of the magnetic plate 10b, the tip of the magnetic brush formed by the rising of the developer by the magnetic field of the magnet roller is separated from the magnetic plate end surface. Without being conveyed, the developer sleeve is conveyed to the nearest ground point B which is the downstream end in the moving direction of the surface of the developing sleeve. When the tip of the magnetic brush reaches the ground point B recently, the tip of the magnetic brush moves away from the end surface of the magnetic plate, and at the same time, the regulation of the developer amount is completed. As a result of such a phenomenon occurring continuously without taking time, the developer amount per unit area on the surface of the developing sleeve conveyed to the developing region becomes substantially uniform. Moreover, this phenomenon is maintained even when the magnetic carrier in the developer is deteriorated and the magnetic carrier is easily magnetized excessively. The developer amount per unit area on the surface of the developing sleeve conveyed to the developing region is maintained substantially uniform even with the lapse of time when the deterioration of the magnetic carrier has progressed.

Next, an effect confirmation test performed for confirming the effect when the restriction blade 10 in the above-described embodiment is used will be described.
In the embodiment, the configuration of the regulating blade 10 in the above-described embodiment is adopted in the developing device of RICOH ProC751EX which is an on-demand printing machine, and the comparative example has a regulating blade 10 ′ as shown in FIG. This is the configuration used. In the comparative example, the mounting position of the non-magnetic plate 10a in the developing container 2 of the same developing device as in the embodiment is cut, and the developing sleeve surface movement of the end surface of the magnetic plate 10b using the same regulating blade 10 as in the embodiment is performed. The upstream end A in the direction is configured to be closest to the surface of the developing sleeve. Specifically, in the comparative example, as shown in FIG. 12, the angle θ1 ′ formed between the virtual line D ′ and the end surface of the magnetic plate 10b is smaller than 0 ° (in FIG. 9, the virtual line D ′ The angle in the counterclockwise direction is positive, and is set to about −15 °. As the developer, a RICOH ProC751EX cyan developer was used.

  In this effect confirmation test, the toner concentration dependency of the amount of developer conveyed to the development area using the developer whose toner concentration is adjusted to 4 [wt%], 7 [wt%], and 10 [wt%], respectively. Confirmed about. The result is as shown in FIG. As can be seen from this result, the amount of variation in the amount of developer conveyed to the development region in accordance with the change in toner density is smaller in the configuration of the example than in the configuration of the comparative example.

  In the comparative example, the upstream end A of the magnetic plate end surface in the developing sleeve surface moving direction is closest to the developing sleeve surface and gradually widens toward the downstream in the developing sleeve surface moving direction. In this configuration, the regulation of the developer amount is completed when the end of the magnetic plate passes through the upstream end A of the developing sleeve surface moving direction. At the initial time when the deterioration of the magnetic carrier is not progressing, the magnetic carrier is appropriately magnetized, so that the tip of the magnetic brush is separated from the magnetic plate at the point A as shown in FIG. Accordingly, at the initial stage, almost simultaneously with the completion of the regulation of the developer amount, the tip of the magnetic brush is separated from the end surface of the magnetic plate and is conveyed toward the developing region while being carried on the surface of the developing sleeve. At this time, the phenomenon in which the tip of the magnetic brush is separated from the end surface of the magnetic plate continuously occurs without taking time, so that the developer amount per unit area on the surface of the developing sleeve conveyed to the developing region becomes substantially uniform.

  However, with the lapse of time when the deterioration of the magnetic carrier has progressed, the magnetic carrier coat layer is peeled off, and the magnetic carrier is easily magnetized excessively. Therefore, the tip of the magnetic brush is not separated from the end face of the magnetic plate at the point A and remains adsorbed on the end face of the magnetic plate. Then, the magnetic brush is pulled by the developing sleeve 11 that moves on the surface, and is pushed by the developer that passes through the point A later, and the surface of the developing sleeve moves while the tip is adsorbed to the magnetic plate. Move downstream in the direction. Then, as shown in FIG. 15, the tip of the magnetic brush is separated from the end surface of the magnetic plate when it reaches the point indicated by B in the drawing, that is, the downstream end of the end surface of the magnetic plate in the moving direction of the developing sleeve. . At this time, if the tip of the magnetic brush is separated from the end surface of the magnetic plate at point B, the upstream side in the moving direction of the developing sleeve surface due to a sudden change in magnetic field, impact, and increased cohesive force due to developer deterioration. Thus, the magnetic brush adsorbed on the end surface of the magnetic plate is also separated from the end surface of the magnetic plate together. As a result, the magnetic brush adsorbed over the entire area of the magnetic plate end face is separated from the magnetic plate end face at once. As a result, a lump of developer separated from the end face of the magnetic plate at a time is carried on the surface of the developing sleeve and conveyed toward the developing area in that state. The developer lump formed by repeating such a phenomenon is carried on the surface of the developing sleeve at a distance corresponding to the length of the developing sleeve surface moving direction on the end surface of the magnetic plate, and sent to the developing area. It will be. As a result, image density unevenness having a period corresponding to the length in the moving direction of the developing sleeve on the end surface of the magnetic plate occurs.

  On the other hand, according to the configuration of the embodiment, the downstream end B of the magnetic plate end surface in the developing sleeve surface moving direction is closest to the developing sleeve surface and gradually increases toward the upstream in the developing sleeve surface moving direction. It has become. In this configuration, the regulation of the developer amount is completed when the end of the magnetic plate passes the downstream end B of the developing sleeve surface moving direction. This is the same even at the initial stage when the deterioration of the magnetic carrier has not progressed, and at the time when the deterioration of the magnetic carrier has progressed. Therefore, at the initial time and over time, almost simultaneously with the completion of the regulation of the developer amount, the tip of the magnetic brush is separated from the end surface of the magnetic plate and is transported toward the developing region while being carried on the surface of the developing sleeve. . At this time, the phenomenon in which the tip of the magnetic brush is separated from the end surface of the magnetic plate continuously occurs without taking time, so that the developer amount per unit area on the surface of the developing sleeve conveyed to the developing region becomes substantially uniform.

  Here, with the lapse of time when the deterioration of the magnetic carrier has progressed, the cohesive force has increased due to the deterioration of the developer, so when the tip of the magnetic brush leaves at the downstream end B of the magnetic sleeve end surface in the developing sleeve surface moving direction, The magnetic brush attracted to the end surface of the magnetic plate on the upstream side in the moving direction of the developing sleeve surface may be separated from the end surface of the magnetic plate together. However, in the configuration of this embodiment, the end surface of the magnetic plate is gradually narrowed toward the downstream side of the developing sleeve surface movement direction. Therefore, even if the tip of the magnetic brush is separated at the downstream end B of the magnetic plate end surface, even if the tip of the upstream magnetic brush is separated from the magnetic plate end surface, the upstream magnetic brush is moved downstream. By being conveyed, the tip immediately comes into contact with the end surface of the magnetic plate and returns to the attracted state again. Therefore, even when the cohesive force is increased due to the deterioration of the developer, the developer lump as in the comparative example is not carried on the surface of the developing sleeve, and the image density unevenness does not occur.

  In the above description, the developer carrying member is configured to convey the developer by moving the surface thereof. However, the surface of the developer carrying member does not move, but the magnetic field inside the developer carrying member. The developer may move on the surface of the developer carrying member.

What has been described above is merely an example, and the present invention has a specific effect for each of the following modes.
(Aspect A)
The magnetic plate 10b is composed of a magnetic plate 10b and a non-magnetic plate 10a disposed on the downstream side of the developer carrying direction of the magnetic plate by the developer carrying member. The magnetic plate 10b is closer to the developer carrying member surface than the end surface of the non-magnetic plate. In the developer regulating member such as the regulating blade 10 in which the end surface of the plate projects, the downstream end of the magnetic plate in the developer transport direction is closest to the surface of the developer carrying member. To do.
According to this, even when the deterioration of the magnetic carrier progresses, the point where the tip of the magnetic brush is separated from the magnetic plate 10b is stabilized at the downstream end B in the developer transport direction on the end surface of the magnetic plate. As a result, the phenomenon that the tip of the magnetic brush separates from the end surface of the magnetic plate continuously occurs without taking time, almost at the same time as the regulation of the developer amount is completed, and the unit area on the surface of the developer carrier that is transported to the development region The amount of developer per hit becomes almost uniform.

(Aspect B)
In the aspect A, the protruding amount of the end face of the magnetic plate from the end face of the nonmagnetic plate is in the range of 0.2 [mm] or more and 0.5 [mm] or less.
According to this, the effect of suppressing the flapping of the magnetic brush by the non-magnetic plate 10a arranged on the downstream side of the magnetic plate 10b in the developer transport direction can be sufficiently obtained, and toner scattering can be suppressed. In addition, the influence of the distance between the nonmagnetic plate 10a and the developer carrier on the amount of developer regulated by the developer regulating member is reduced, and the gap between the nonmagnetic plate 10a and the developer carrier is highly accurate. Management becomes unnecessary.

(Aspect C)
In the aspect A or B, the magnetic plate 10b is thinner than the nonmagnetic plate 10a, and the thickness of the magnetic plate 10b is in the range of 0.2 [mm] or more and 0.5 [mm] or less. If the thickness of the magnetic plate 10b is too thick, the effect of gathering the magnetic brush in one place is reduced, and the fluctuation of the developer regulation amount with respect to the change in the distance between the developer regulation member and the developer carrier is large. Thus, it becomes difficult to manage the distance between the developer regulating member and the developer carrier. According to this aspect, since the variation in the developer regulation amount with respect to the change in the interval between the developer regulating member and the developer carrying member is small, the management of the interval between the developer regulating member and the developer carrying member is relatively easy. Thus, the developer regulation amount can be stabilized.

(Aspect D)
The developer passes between the developer carrying member such as the developing sleeve 11 that carries and carries the developer on the surface, and the surface of the developer carrying member, and passes between the surface of the developer carrying member. In the developing device 4 provided with the developer regulating member that regulates the amount of developer conveyed to the developing region, the developer regulating member according to any one of the above aspects A to C is used as the developer regulating member. It is used.
According to this, since the amount of developer per unit area on the surface of the developer carrying member conveyed to the developing region can be maintained substantially uniform over time, stable developability can be obtained from the initial stage over time.

(Aspect E)
A developer is supplied to the latent image on the latent image carrier on the latent image carrier such as the photosensitive member 1 that carries the latent image on the surface and moves on the surface, and in the development area facing the latent image carrier. A developing means for developing the latent image, and an image forming apparatus for forming an image on the recording material by finally transferring an image obtained by the development by the developing means onto the recording material. As a means, the developing device according to the above aspect D is used.
According to this, it is possible to form a high-quality image with little vomit feeling from the initial stage over time.

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Developing container 4 Developing device 10 Restriction blade 10a Magnetic plate 10b Nonmagnetic plate 11 Developing sleeve 18 Process cartridge 20 Image forming unit 21 Optical writing unit 22 Secondary transfer device 62 Primary transfer bias roller 100 Printer unit 110 Intermediate transfer Belt 200 Paper feeder 300 Scanner 400 Automatic document feeder

JP 2004-191529 A JP 2007-86312 A

Claims (5)

A magnetic plate, and a non-magnetic plate disposed downstream of the developer carrying direction of the magnetic plate by the developer carrier. The magnetic plate has a surface closer to the developer carrier than the end surface of the non-magnetic plate. In the developer regulating member whose end face protrudes,
A developer regulating member characterized in that, of the end surfaces of the magnetic plate, the downstream end in the developer transport direction is closest to the surface of the developer carrier. The developer regulating member according to claim 1,
The developer regulating member, wherein an amount of protrusion of the end face of the magnetic plate from the end face of the nonmagnetic plate is in a range of 0.2 [mm] or more and 0.5 [mm] or less. In the developer regulating member according to claim 1 or 2,
The developer regulating member, wherein the magnetic plate is thinner than the non-magnetic plate, and the thickness of the magnetic plate is in the range of 0.2 [mm] to 0.5 [mm]. A developer carrying member carrying and carrying the developer on the surface;
A developer regulating member that is disposed to face the surface of the developer carrying member and regulates the amount of developer conveyed to the developing region by allowing the developer to pass between the surface of the developer carrying member; In the developing device,
A developing device using the developer regulating member according to any one of claims 1 to 3 as the developer regulating member. A latent image carrier that carries a latent image on the surface and moves on the surface;
Developing means for developing the latent image by supplying a developer to the latent image on the latent image carrier in a development region facing the latent image carrier;
In an image forming apparatus for finally transferring an image obtained by development by the developing means onto a recording material to form an image on the recording material,
An image forming apparatus using the developing device according to claim 4 as the developing means.

Images