JP2010197832A - Developing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device for constantly keeping a developer carried by a developer carrier and performing stable image output. <P>SOLUTION: An adjusting member 46 moves so as to be close to or separate from a space S between the developer carrier 40 and a regulating member 45, and at least one of supply quantity of the developer 41 to the space S and pressure of the developer 41 of the space S is made constant. Therefore, the adjusting member 46 keeps the developer 41 carried by the developer carrier 40 constant in agreement with liquid level variation of the developer 41 in a casing 42 varying with a state of the developer 41. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a developing device used in, for example, an electrophotographic image forming apparatus, and an image forming apparatus using the developing device.

  An electrophotographic image forming apparatus includes an image carrier, a charging device that uniformly charges the image carrier, an exposure device that converts an electric charge on the image carrier into an electrostatic latent image, and an image carrier. A developing device that converts an electrostatic latent image into a visible image with a developer, a transfer device that electrically and mechanically transfers the visible image on the image carrier to a recording material, and a visualized developer on the recording material And a fixing device that permanently fixes the toner by heat or pressure.

  In recent years, especially with the increase in full-color output, each of the above-described devices is required to have a longer life, higher reliability, and higher image quality as well as a smaller and faster device.

  By the way, especially for long life, high reliability, and high image quality, there is a large presence of a developing device that visualizes an electrostatic latent image with a developer for the first time. The differences are well known.

  As a major concern, the performance required as a developing device is that a stable developer can be supplied onto a developer carrier called a developing roller through durability from the beginning.

  However, it is difficult to stably supply the developer to the developing roller due to various factors.

  For example, in a two-component developing device composed of a carrier and a toner, the state of the developer in the developing device changes depending on the environment, the mixing ratio of the carrier and the toner, or the driving rotational speed.

  Further, as the durability is increased from the initial state, the characteristics as a developer change due to the progress of the wear of the carrier surface and the classification of the toner components.

  These are so-called developer fluidity. For example, if the fluidity is high, the developer in the developing device is likely to circulate, and if the fluidity is low, the developer in the developing device is less likely to move. It becomes difficult to circulate.

  Further, if the fluidity is high, the developer amount relative to the layer thickness of the developer carried on the developer carrier is smoother in the movement of the developer on the regulating member for adjusting the developer amount on the developer carrier. Therefore, if the fluidity is low, the developer amount with respect to the layer thickness of the developer carried on the developer carrier is less likely to move the developer on the regulating member. Since it becomes difficult to be supplied onto the developer carrying member, the amount is relatively reduced.

  Of course, the developer transport amount on the developer carrier is not determined solely by the fluidity of the developer. However, in many cases, the change in the fluidity of the developer is caused by the circulation property or the developer carrier. It can be easily imagined that it affects the characteristics such as the developer conveyance amount.

  The change in developer fluidity is expressed as an index “bulk density” which is an index of how much developer is present in the same volume.

  In other words, high developer fluidity means that a lot of developer can be stored in the same volume, and conversely low developer fluidity means that there is not much developer in the same volume. It means that it cannot be accommodated.

  Therefore, when the developer tank is circulated stably with respect to the change in the developer fluidity due to them, there is a certain margin to the “bulk density” that changes due to the change in the developer fluidity. It is necessary to provide a space.

  An increase in bulk density means that the flowability of the developer is high, but since the same amount of developer is always present in the developing device, the volume of the developer increases as the bulk density increases. It will be.

  That is, even when the developer amount is the same, the developer level in the developing device rises.

  Alternatively, a low bulk density means that the developer level in the developing device is lowered.

  Therefore, even when the bulk density changes and the liquid level of the developer in the developing device increases, there must be a space for receiving the increased liquid level.

  If there is no allowance, the developer is tightly packed in the space in the developing device, and the developer does not circulate, or in the worst case, the circulating member is damaged.

  Further, when the developer is clogged, for example, the supplied toner does not enter the developer, and it becomes difficult to exhibit sufficient mixing and stirring performance.

  Therefore, as a developing device that solves the above-described problems, a plate-like member that is movable in one direction is provided at the end of the partition wall in the middle of the circulation path, and the supplied toner is obtained by moving the member. The circulation path of the developer containing the toner is partly changed (see Japanese Patent Application Laid-Open No. 2006-251158: Patent Document 1).

  In this way, stable circulation is always ensured, and the supplied toner is prevented from reaching the developing roller directly without being mixed.

JP 2006-251158 A

  However, in the conventional developing device, the circulation path of the developer is changed to secure a certain degree of circulation. However, the developer supply capability to the developing roller or the like can be changed by changing the circulation path. Even if the amount of developer to circulate is kept constant, the developer's state, for example, fluidity and bulk density changes, so the developer supply to the developing roller will change and the liquid level will remain constant. It is not the only way to solve it.

  In other words, even if the developer circulation in the circulation path is kept good, the level of the liquid is only constant, and the supply to the developing roller does not correspond to the change in the state of the developer. If the property is good, it will be difficult to carry on the developing roller, and if the fluidity is bad, it will be easy to carry on the developing roller. If the liquid level is simply constant, the supply performance is not constant.

  In addition, switching the circulation path in the middle of the circulation path causes a pulsation of developer circulation at the moment of switching, and the change in the liquid level immediately after switching actually becomes large. There is also a problem that it cannot be used because noise occurs in an image or the like until the image becomes stable.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a developing device and an image forming apparatus that can keep the developer carried on the developer carrying member constant and enable stable image output.

In order to solve the above problems, the developing device of the present invention provides:
A casing having an opening;
A developer carrier that is disposed in the opening so as to be partially exposed from the opening of the casing, and that carries a developer to form a visible image on the image carrier;
A regulation that keeps a constant amount of developer on the developer carrier while being disposed at the opening of the casing so as to face the developer carrier with a space between the developer carrier and the developer carrier. Members,
An agitating and conveying member disposed in the casing and conveying the developer while stirring;
A supply conveying member that is disposed in the casing and supplies the developer conveyed from the stirring and conveying member to the developer carrier;
The developer is disposed in the casing and moves so as to approach or separate from the space between the developer carrying member and the regulating member, and the amount of developer supplied to the space and the development of the space And an adjusting member that makes at least one of the pressures of the agent constant.

  According to the developing device of the present invention, the adjusting member moves so as to approach or separate from the space between the developer carrier and the regulating member, and the amount of developer supplied to the space, and Since at least one of the developer pressures in the space is made constant, the adjusting member is carried on the developer carrying body in accordance with the change in the developer level in the casing that changes depending on the state of the developer. Keep developer constant. The liquid level fluctuation of the developer occurs, for example, due to factors such as fluctuation of the developer fluidity.

  Accordingly, it is possible to keep the supply property to the developer carrying member optimal and to enable stable image output.

In the developing device of one embodiment,
In the casing, a partition wall is provided between the stirring and conveying member and the supply and conveying member,
The adjusting member moves while constantly overlapping the tip of the partition wall.

  According to the developing device of this embodiment, the adjustment member moves while always overlapping the tip of the partition wall, so that the adjustment member is always in a position overlapping the tip of the partition wall.

  For this reason, the developer can be prevented from coming and going over the partition wall between the supply conveyance member and the agitation conveyance member, and a stable developer circulation path can be secured.

  Therefore, there is no pulsation fluctuation of the developer circulating in the casing, and the developer circulation property can be kept optimal.

In the developing device of one embodiment,
A thickness detector for detecting the thickness of the developer on the developer carrier after being kept constant by the regulating member;
And a control unit that moves the adjustment member based on the result of the thickness detection unit.

  According to the developing device of this embodiment, since the adjusting member is moved based on the result of the thickness detecting unit, the developer carried on the developer carrying member can be reliably kept constant.

In the developing device of one embodiment,
The casing is
A supply unit for supplying developer into the casing;
A discharge unit that discharges an excess amount of developer exceeding a certain amount in the casing to the outside of the casing.

  According to the developing device of this embodiment, since the casing includes the supply unit and the discharge unit, by supplying the developer and discharging the excess developer in a timely manner, due to the fluidity of the developer and the like. Liquid level change occurs.

  However, even when the liquid level changes, the supply of the developer amount corresponding to the liquid level change to the developer carrying member can be kept constant by the adjusting member.

  An image forming apparatus according to the present invention includes the developing device.

  According to the image forming apparatus of the present invention, since the developing device is provided, an image density, a halftone image, and the like can be output uniformly, particularly in an electrophotographic image forming apparatus.

  According to the developing device of the present invention, the adjusting member moves so as to approach or separate from the space between the developer carrier and the regulating member, and the amount of developer supplied to the space, and Since at least one of the developer pressures in the space is made constant, the developer carried on the developer carrying member can be kept constant, and stable image output is possible.

  According to the image forming apparatus of the present invention, since the developing device is provided, an image density, a halftone image, and the like can be output uniformly, particularly in an electrophotographic image forming apparatus.

1 is a simplified configuration diagram showing an embodiment of an image forming apparatus of the present invention. It is explanatory drawing which shows one Embodiment of a developing device, and shows the state with the high liquid level of a developing agent. It is explanatory drawing which shows one Embodiment of a developing device, and shows the state with the low liquid level of a developing agent. It is a top view of a developing device. It is explanatory drawing explaining the comparative example of a developing device. It is a simplified block diagram of another developing device. It is a top view of another developing device.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

(First embodiment)
FIG. 1 is a simplified configuration diagram showing an embodiment of an image forming apparatus according to the present invention. This image forming apparatus is a full-color electrophotographic apparatus, and includes an image forming device 20 and a fixing device 8.

  The image forming apparatus 20 forms an image by attaching unfixed toner to the recording material 11. The fixing device 8 melts the toner and fixes it on the recording material 11.

  The image forming device 20 includes a transfer belt 5, four image forming units 21 disposed along the transfer belt 5, and a secondary transfer device 7 disposed facing the transfer belt 5.

  The image forming unit 21 forms a toner image and transfers the toner image to the transfer belt 5. The secondary transfer device 7 transfers the toner image transferred to the transfer belt 5 to the recording material 11.

  An image forming unit 21 that forms a black (Bk) toner image, an image forming unit 21 that forms a yellow (Y) toner image, an image forming unit 21 that forms a magenta (M) toner image, and cyan (C The image forming units 21 for forming the toner images are sequentially arranged from the upstream side to the downstream side of the transfer belt 5.

  Each image forming unit 21 includes an image carrier 1, a charging device 2, an image exposure device 3, a developing device 4, a transfer belt 5, and a primary transfer device 6.

  The image carrier 1 is a so-called photoconductor. The charging device 2 uniformly charges the surface of the image carrier 1 to form a potential. The image exposure device 3 irradiates light at a potential charged to a desired potential by the charging device 2 in order to form a predetermined electrostatic latent image. The developing device 4 forms a mirror image by attaching toner to an area where an electrostatic latent image is formed by an electric field or the like. The primary transfer device 6 moves the toner on the image carrier 1 made into a mirror image onto the transfer belt 5.

  Next, the operation of this image forming apparatus will be described.

  The toner image developed on the image carrier 1 of the image forming unit 21 is primarily transferred onto the transfer belt 5 at a contact position with the transfer belt 5.

  Each time the toner image transferred onto the transfer belt 5 passes through each image forming unit 21, each color is superimposed thereon, and finally a full-color toner image is formed on the transfer belt 5. Is done.

  Thereafter, the full-color toner image on the transfer belt 5 is secondarily transferred collectively onto the recording material 11 by the secondary transfer device 7 downstream of the transfer belt 5.

  Then, the recording material 11 passes through the fixing device 8 downstream of the conveyance path of the recording material 11, whereby the toner image is fixed, and is discharged to the outside of the device.

  On the other hand, in the primary transfer device 6, the toner may not completely move on the transfer belt 5 and may remain slightly on the image carrier 1. At this time, the toner remaining on the image carrier 1 is mechanically removed from the image carrier 1 by the cleaning device 9 and electrically removed by the charge eliminating device 12.

  Further, in the mirror image formed on the transfer belt 5, the toner cannot completely move in the secondary transfer device 7, and may remain as a residual toner slightly on the transfer belt 5. It is removed electrically and mechanically by the device 10.

  As shown in FIG. 2A, the developing device 4 includes a casing 42 that contains a developer 41, a developer carrier 40, a regulating member 45, a stirring and conveying member 44, a supply and conveying member 43, and an adjusting member 46. And have.

  The developer 41 includes toner and a carrier. The casing 42 has an opening 42c.

  The developer carrier 40 is disposed in the opening 42c such that a part of the developer carrier 40 is exposed from the opening 42c of the casing 42. The developer carrier 40 carries the developer 41 and forms a visible image on the image carrier 1. The image carrier 1 and developer carrier 40 rotate in the direction indicated by the arrows in the figure.

  The regulating member 45 is disposed in the opening 42 c of the casing 42 so as to face the developer carrier 40 with a space S between the restriction member 45 and the developer carrier 40. The regulating member 45 keeps the amount of developer on the developer carrier 40 constant.

  The stirring and conveying member 44 and the supply and conveying member 43 are disposed in the casing 42. The stirring and conveying member 44 conveys the developer 41 while stirring. The supply conveyance member 43 supplies the developer 41 conveyed from the agitation conveyance member 44 to the developer carrier 40. The agitating / conveying member 44 and the supply / conveying member 43 rotate in a direction indicated by an arrow in the drawing.

  The adjustment member 46 is disposed in the casing 42. The adjusting member 46 moves so as to approach or separate from the space S between the developer carrier 40 and the regulating member 45, and supplies the developer 41 to the space S, and the space S. At least one of the pressures of the developer 41 is made constant.

  A partition wall 42 a is provided in the casing 42 between the stirring and conveying member 44 and the supply and conveying member 43. That is, the partition wall 42a divides the inside of the casing 42 into a first chamber in which the agitating and conveying member 44 is present and a second chamber in which the supply and conveying member 43, the developer carrier 40 and the adjusting member 46 are present. .

  The adjusting member 46 has a triangular cross section and is arranged so that the hypotenuse of the triangle faces the space S. The adjustment member 46 is made of resin, for example. The adjustment member 46 is moved by the actuator 47. The adjusting member 46 moves while constantly overlapping the tip of the partition wall 42a.

  The actuator 47 is controlled by the control unit 50. The control unit 50 controls the control unit 50 based on the result of the thickness detection unit 51 to move the adjustment member 46. The thickness detector 51 detects the thickness of the developer 41 on the developer carrier 40 after being kept constant by the regulating member 45. The thickness detector 51 is, for example, an optical sensor.

  That is, when the thickness of the developer 41 is smaller than the reference value as a result of the thickness detection unit 51, the control unit 50 moves the adjustment member 46 closer to the space S, while adjusting when the thickness of the developer 41 is larger than the reference value. The member 46 is separated from the space S.

  Next, the flow of the developer 41 in the casing 42 will be described. As shown in FIG. 3, the developer is transported from one end in the longitudinal direction of the stirring transport member 44 to the other end by the stirring transport member 44 as indicated by an arrow.

  The developer 41 is transferred to the supply conveyance member 43 at the other end in the longitudinal direction of the agitation conveyance member 44. That is, notches 42 b are provided at both ends of the partition wall 42 a, and the developer passes through the one notch 42 b and moves to the supply conveyance member 43.

  Thereafter, the developer is transported and supplied to the developer carrier 40 by the supply transport member 43 as indicated by an arrow. At this time, a certain amount of developer is supplied to the developer carrier 40 by the adjusting member 46. In the figure, the developer carrier 40 and the adjustment member 46 are indicated by phantom lines.

  On the other hand, the developer scraped off from the developer carrier 40 by the regulating member 45 shown in FIG. 2A is blocked by the adjusting member 46 so as not to enter the first chamber where the agitating and conveying member 44 exists, and is again supplied and conveyed. Returned to member 43.

  Thereafter, the developer passes through the other notch 42 b of the partition wall 42 a and moves to the stirring and conveying member 44. The developer circulates through the agitating and conveying member 44 and the supply and conveying member 43.

  Next, the operation of the adjustment member 46 will be described. As shown in FIG. 2A, the developer 41 has a higher liquid level than the supply conveyance member 43. That is, the amount of the developer 41 supplied from the supply conveyance member 43 to the developer carrier 40 is increased, and the powder pressure of the developer 41 in the vicinity of the regulating member 45 is high. At this time, since the pressure of the developer 41 to be pushed in becomes higher than the restriction amount of the developer 41 in the space S, the thickness of the developer 41 on the developer carrier 40 after being restricted by the restriction member 45. Is higher than expected.

  The thickness detector 51 detects the thickness of the developer 41 on the developer carrier 40, and the controller 50 determines that the thickness of the developer 41 is greater than the reference value as a result of the thickness detector 51. The adjustment member 46 is separated from the space S. As a result, at least one of the supply amount of the developer 41 to the space S and the pressure of the developer 41 in the space S is kept constant.

  On the other hand, as shown in FIG. 2B, the developer 41 has a lower liquid level than the supply conveyance member 43. That is, the amount of the developer 41 supplied from the supply conveyance member 43 to the developer carrier 40 is reduced, and the powder pressure of the developer 41 in the vicinity of the regulating member 45 is low. At this time, since the pressure of the developer 41 to be pushed becomes lower than the regulated amount of the developer 41 in the space S, the thickness of the developer 41 on the developer carrier 40 after being regulated by the regulating member 45. Is lower than expected.

  Then, the thickness detector 51 detects the thickness of the developer 41 on the developer carrier 40, and the controller 50 determines that the thickness of the developer 41 is smaller than the reference value as a result of the thickness detector 51. The adjusting member 46 is brought close to the space S. As a result, at least one of the supply amount of the developer 41 to the space S and the pressure of the developer 41 in the space S is kept constant.

  In short, as shown in FIGS. 2A and 2B, the adjusting member 46 works to keep the powder pressure of the developer 41 constant with respect to changes in the supply amount of the developer 41, or It is said that the supply amount of the developer 41 to the surface of the developer carrier 40 is finally made constant by working to keep the supply amount of the developer 41 constant against fluctuations in the powder pressure. It will be.

  As a result, a constant amount of developer 41 is always supplied to the surface of the developer carrier 40, and the integral value of the developer amount of the developer 41 and the powder pressure in the regulating member 45 is always constant. As a result, the developer amount on the developer carrier 40 is stably supplied to the image carrier 1.

  Next, a comparative example of the developing device will be described. As shown in FIG. 4, a partition member 146 is used instead of the adjustment member 46 of FIG. 2A. In FIG. 4, the same reference numerals as those in FIG. 2A have the same configurations as those in FIG.

  As shown in FIG. 4, the partition member 146 is attached to the partition wall 42 a of the casing 42, and is positioned so as not to move up and down, left and right, and front and rear with respect to the casing 42.

  When the liquid level with respect to the supply / conveyance member 43 is low, the amount of the developer 41 supplied to the developer carrier 40 is reduced, and the powder pressure of the developer 41 in the vicinity of the regulating member 45 is reduced. At this time, since the pressure of the developer 41 to be pushed becomes lower than the regulated amount of the developer 41 in the space S, the thickness of the developer 41 on the developer carrier 40 after being regulated by the regulating member 45. Will be lower than expected.

  On the other hand, when the liquid level with respect to the supply conveyance member 43 is high, the amount of the developer 41 supplied to the developer carrier 40 increases, and the powder pressure of the developer 41 in the vicinity of the regulating member 45 increases. At this time, since the pressure of the developer 41 to be pushed in becomes higher than the restriction amount of the developer 41 in the space S, the thickness of the developer 41 on the developer carrier 40 after being restricted by the restriction member 45. Will be higher than expected.

  Furthermore, the powder pressure at which the developer 41 tries to return to the supply conveyance member 43 also changes in accordance with the powder pressure change in the vicinity of the regulating member 45 due to the liquid level fluctuation of the developer 41, and therefore the developer carrier 40. The performance of replacing the developer 41 in FIG.

  According to the developing device having the above configuration, the adjusting member 46 moves so as to approach or separate from the space S between the developer carrier 40 and the regulating member 45, and the developer into the space S Since at least one of the supply amount of 41 and the pressure of the developer 41 in the space S is made constant, according to the change in the liquid level of the developer 41 in the casing 42 that changes depending on the state of the developer 41, The adjusting member 46 keeps the developer 41 carried on the developer carrying body 40 constant. Therefore, the supply property to the developer carrying member 40 can be kept optimal, and stable image output is possible.

  Further, since the adjusting member 46 moves while always overlapping the tip of the partition wall 42a, the adjusting member 46 is always in a position overlapping the tip of the partition wall 42a. Therefore, the developer 41 can be prevented from coming and going between the supply conveyance member 43 and the agitation conveyance member 44 across the partition wall 42a, and a stable circulation path of the developer 41 can be secured. Therefore, there is no fluctuation in the pulsation of the developer 41 circulating in the casing 42, and the circulatory property of the developer 41 can be kept optimal.

  Further, since the adjusting member 46 is moved based on the result of the thickness detecting unit 51, the developer 41 carried on the developer carrying body 40 can be reliably kept constant.

  Further, according to the image forming apparatus having the above configuration, since the developing device 4 is provided, an image density, a halftone image, and the like can be output uniformly, particularly in an electrophotographic image forming apparatus.

(Second Embodiment)
FIG. 5 shows a second embodiment of the developing device of the present invention. The difference from the first embodiment will be described. In the second embodiment, the configuration for moving the adjustment member 46 is different. In the second embodiment, the same reference numerals as those in the first embodiment are the same as those in the first embodiment, and the description thereof is omitted.

  As shown in FIG. 5, a spring 48 is used instead of the actuator 47 of FIG. 2A. That is, the adjustment member 46 is attached to the casing 42 via the spring 48. The adjustment member 46 is constantly urged and biased toward the space S by the action of the spring 48.

  When the developer 41 has a lower liquid level than the supply conveyance member 43, the adjustment member 46 moves so as to approach the space S by the action of the spring 48, and the developer carrier The adjustment member 46 is in a state where the developer 41 is pushed against the powder pressure of the developer 41 in the second chamber (closed space) where the control member 45, the regulating member 45, and the supply conveyance member 43 exist. The powder pressure is maintained.

  On the other hand, when the developer 41 has a higher liquid level than the supply conveyance member 43, the adjustment member 46 moves so as to approach the space S by the action of the spring 48, and the developer carrying member. The adjustment member 46 is pushed back against the powder pressure of the developer 41 in the second chamber (closed space) where the control member 45, the regulating member 45, and the supply conveyance member 43 are present. I keep it.

  That is, the supply amount of the developer 41 to the developer carrier 40 due to the different liquid levels, and thus the powder in the closed space formed by the developer carrier 40, the regulating member 45, the adjusting member 46, and the supply conveying member 43. The adjustment member 46 is movable by the pressure.

  In short, the adjusting member 46 works to keep the powder pressure of the developer 41 constant with respect to changes in the supply amount of the developer 41, or develops against changes in the powder pressure of the developer 41. By working so as to keep the supply amount of the agent 41 constant, the supply amount of the developer 41 to the surface of the developer carrier 40 is finally made constant.

  As a result, a constant amount of developer 41 is always supplied to the surface of the developer carrier 40, and the integral value of the developer amount of the developer 41 and the powder pressure in the regulating member 45 is always constant. As a result, the developer amount on the developer carrier 40 is stably supplied to the image carrier 1.

(Third embodiment)
FIG. 6 shows a third embodiment of the developing device of the present invention. In the third embodiment, the same reference numerals as those in the first embodiment are the same as those in the first embodiment, and the description thereof is omitted.

  As shown in FIG. 6, the casing 42 includes a supply unit 60 and a discharge unit 61. The supply unit 60 supplies the developer 41 into the casing 42. The discharge unit 61 discharges an excess amount of developer 41 exceeding a certain amount in the casing 42 to the outside of the casing 42.

  The supply unit 60 is disposed at one end in the longitudinal direction of the stirring and conveying member 44, and the discharge unit 61 is disposed at one end in the longitudinal direction of the supply and conveying member 43.

  The flow of the developer 41 in the casing 42 will be described. The developer 41 is supplied from the supply unit 60 into the casing 42 and, as described in the first embodiment, as indicated by the arrow, the casing 42. Circulate inside. Then, the excess developer 41 exceeding a certain amount in the casing 42 is discharged from the discharge portion 61 to the outside of the casing 42.

  At this time, by supplying the developer 41 and discharging the excess developer 41 in a timely manner, a change in the liquid level due to the fluidity of the developer 41 occurs. That is, this is because the liquid level fluctuation due to the change in the state of the developer 41 changes greatly depending on the discharge state of the developer 41, and the amount of the developer 41 existing in the developing device 4 changes accordingly.

  However, even when the liquid level changes, the adjusting member 46 can keep the supply of the amount of the developer 41 corresponding to the liquid level change to the developer carrier 40 constant.

  In addition, this invention is not limited to the above-mentioned embodiment. For example, at least one of the supply amount of the developer 41 to the space S and the pressure of the developer 41 in the space S is directly measured, and this result is reflected in the control unit 50 to perform this control. The adjustment member 46 may be controlled by the unit 50 so that at least one of the supply amount and the pressure is made constant.

  Further, the toner density of the recording material 11 is detected, and this result is reflected in the control unit 50. When the toner density is smaller than the reference value, the adjusting member 46 approaches the space S, while the toner density is lower than the reference value. When it is larger, the adjusting member 46 may be separated from the space S. That is, the control member 50 may control the adjustment member 46 so that at least one of the supply amount and the pressure is made constant.

  Further, in place of the spring of the second embodiment, the deflection of the adjustment member itself may be used.

  The image forming apparatus may be a copy, a FAX, a printer, or the like regardless of color or monochrome.

DESCRIPTION OF SYMBOLS 1 Image carrier 2 Charging device 3 Image exposure device 4 Developing device 5 Transfer belt 6 Primary transfer device 7 Secondary transfer device 8 Fixing device 9 Cleaning device 10 Transfer belt cleaning device 11 Recording material 12 Static elimination device 20 Image forming device 21 Image Formation unit 40 Developer carrier 41 Developer 42 Casing 42a Partition wall 42b Notch portion 42c Opening portion 43 Feeding conveyance member 44 Stirring conveyance member 45 Restriction member 46 Adjustment member 47 Actuator 48 Spring 50 Control unit 51 Thickness detection unit 60 Supply unit 61 Discharge portion S space (between developer carrier and regulating member)

Claims (5)

A casing having an opening;
A developer carrier that is disposed in the opening so as to be partially exposed from the opening of the casing, and that carries a developer to form a visible image on the image carrier;
A regulation that keeps a constant amount of developer on the developer carrier while being disposed at the opening of the casing so as to face the developer carrier with a space between the developer carrier and the developer carrier. Members,
An agitating and conveying member disposed in the casing and conveying the developer while stirring;
A supply conveying member that is disposed in the casing and supplies the developer conveyed from the stirring and conveying member to the developer carrier;
The developer is disposed in the casing and moves so as to approach or separate from the space between the developer carrying member and the regulating member, and the amount of developer supplied to the space and the development of the space A developing device comprising: an adjustment member that makes at least one of the pressures of the agent constant. The developing device according to claim 1,
In the casing, a partition wall is provided between the stirring and conveying member and the supply and conveying member,
The developing device according to claim 1, wherein the adjusting member moves while constantly overlapping the tip of the partition wall. The developing device according to claim 1 or 2,
A thickness detector for detecting the thickness of the developer on the developer carrier after being kept constant by the regulating member;
And a control unit that moves the adjustment member based on the result of the thickness detection unit. The developing device according to any one of claims 1 to 3,
The casing is
A supply unit for supplying developer into the casing;
A developing device, comprising: a discharge unit that discharges an excess amount of developer exceeding a certain amount in the casing to the outside of the casing.   An image forming apparatus comprising the developing device according to claim 1.

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