JP3724568B2 - Developing device and image forming apparatus using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a developing device including a developer conveying member and a developer receiving member, and an image forming apparatus using the developing device.
[0002]
[Prior art]
Conventionally, as a developing device used in an image forming apparatus such as a copying machine or a printer, only a toner is used without using a carrier in addition to a two-component developing method using a toner and a carrier as a developer 1 A component developing system is known.
[0003]
In the one-component color developing system, each color developing device rotates intermittently in a rotary manner as in the rotary development and develops in contact with the photoreceptor, or in a state where the developing device is substantially fixed as in the tandem. What is developed is known.
[0004]
Here, as a one-component developing type developing device using only toner as a developer, the toner stirred by the agitator is sent to the supply roller, and the supply roller is rotated to supply the toner to the developing roller. The toner is transported by the rotation of the developing roller, and a regulating blade is pressed against the surface of the developing roller to regulate the amount of toner to be transported and frictionally charged so that the toner is guided to the developing area facing the photoconductor for development. What was made was used.
[0005]
Further, in the conventional developing device, in the developing area where the developing roller and the photosensitive member face each other, the developing roller and the photosensitive member rotate so that their peripheral surfaces move in the same direction from the upper side to the lower side. In many cases, however, the development roller and the photoreceptor move in the same direction from the lower side to the upper side in the development area. Some have been proposed to rotate.
[0006]
On the other hand, there has also been proposed a device in which a return member is provided in the vicinity of the regulation blade for returning the toner scraped off after regulation to the toner storage unit.
[0007]
[Problems to be solved by the invention]
If a return member for returning the toner is provided in the toner accommodating portion, mechanical stress is applied to the toner, and the toner life is shortened. Further, in a system in which the developing device is fixed, such as a tandem system, it is necessary to provide a member such as a discharge roller to efficiently promote toner circulation in order to efficiently store the toner in the toner storage unit. This is a factor that causes toner to deteriorate early.
[0008]
For this reason, fogging and solid density change are conspicuous due to early image deterioration, which is a serious cause of deterioration in image quality. Further, as a result of the increase in the amount of toner used due to fogging, the running cost of consumables increases.
[0009]
[Means for Solving the Problems]
SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems, and to effectively and smoothly supply and use a developer, to reduce stress applied to the developer, and to extend the life of the developer.
Therefore, the invention of claim 1 is characterized in that a developer accommodating portion is formed in a direction in which the developer scraped off from the developer supply member that supplies the developer to the developer carrier is dropped by gravity, and the developer. A developer temporary storage portion is formed by a developer receiving member and a developer supply member, which are provided on the lower side of the supply member and have a flexible scraper attached to the tip, and are provided rotatably in the developer storage portion. A developing device in which a developer is conveyed from the developer accommodating portion to the temporary storage portion by a flexible developer conveying member attached to a front end portion of the developer agitating member, wherein the developer The developer conveying member is rotated by the rotation of the agitating member, conveys the developer from the developer accommodating portion along the developer container wall surrounding the developer accommodating portion, and enters the scraper from its front end side. Developer in contact And wherein the pass.
The invention according to claim 2 is characterized in that the scraper is pushed upward and deformed by contact with the developer conveying member, and the transferred developer is moved to the temporary storage section.
The invention of claim 3 is characterized in that the flexibility of the scraper is greater than the flexibility of the developer conveying member.
The invention of claim 4 is characterized in that the rotation direction of the developer conveying member is opposite to the rotation direction of the developer supply member.
The invention according to claim 5 is characterized in that the developer carrier is in contact with or close to the image carrier from below.
According to a sixth aspect of the present invention, there is provided an image forming apparatus including the developing device having the above-described configuration.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
FIG. 1 is a diagram for explaining an example of an embodiment of a developing device of the present invention.
The developing device main body 20 includes a toner storage container 26 that stores toner (mesh portion in the figure), a toner storage unit 27 formed in the toner storage container 26, and a toner agitation disposed in the toner storage unit 27. A member 29, a toner receiving member 30 provided above the toner receiving portion 27, a toner supply roller 31 disposed above the toner receiving member 30, and a toner receiving roller 30 provided on the toner receiving member 30. A receiving sheet 32 that is in contact with the lower portion, a developing roller 33 that is in contact with the toner supply roller 31 and faces the photoconductor 17 with a slight gap (about 100 to 300 μm), and development A regulating blade 34 and a regulating blade 34 that are in contact with the lower side of the roller 33 are attached, and the falling toner regulated by the regulating blade hits and freely falls to the toner accommodating portion. Housing wall 45 which functions as a toner path member which is composed of upper seal 46 for preventing toner leakage while contact in the direction of recovering the toner remaining on the developing roller after development.
[0011]
The developing roller 33 and the photoconductor 17 are opposed to each other with a slight space therebetween, and are driven to rotate in opposite directions as indicated by arrows in the drawing. Moves in the same direction from the bottom to the top, and a developing bias in which an AC voltage is superimposed on a DC voltage is applied to the developing roller from a developing bias power source (not shown) to generate an oscillating electric field between the developing roller and the photosensitive member. The toner is supplied to the electrostatic latent image portion formed on the photosensitive member from the developing roller and developed. In the present embodiment, the developing roller and the photosensitive member are opposed to each other with a slight gap in the developing region. However, the developing roller and the photosensitive member may be brought into contact with each other in the developing region to perform development. Is possible.
[0012]
Further, in the developing device of the present embodiment, the toner containing portion 27 contains toner that does not bury the regulating blade 34. This is because if the amount of toner is so large that the regulating blade 34 is buried, the circulation path through which the toner scraped off from the regulating blade 34 is smoothly returned to the toner containing portion 27 is obstructed, and the regulating blade 34 is moved to the developing roller 33. This is because the role of scraping off excess toner from the upper toner and regulating the amount of toner conveyed to the development area and the role of appropriately charging the toner are hindered. Further, the toner containing portion 27 is rotatably provided with a stirring member 29 having a flexible conveying member 29a attached to the tip thereof so as to rotate in a direction opposite to the supply roller 31. A number of slits are formed in the transport member 29a. Then, by rotating the stirring member 29, the toner stored in the toner storage unit 27 is supplied to the gap (temporary storage unit) between the toner receiving member 30 and the supply roller 31 by the conveying member 29a attached to the stirring member. I am doing so.
[0013]
Further, a supply roller 31 provided with a conductive elastic layer having a plurality of cells on the outer peripheral portion is disposed in the vicinity of the temporary storage portion, and the elastic layer of the supply roller 31 is pressed against the developing roller 33. I have to. The supply roller 31 and the developing roller 33 are rotated in the same direction, and the respective peripheral surfaces are moved in the opposite directions in the contact areas to be rubbed against each other, and applied to the developing roller from a developing bias power source (not shown). A voltage equivalent to the developing bias voltage is applied to the supply roller.
[0014]
One end of a receiving sheet 32 formed in a plate shape is attached to the toner receiving member 30, and the receiving sheet 32 is brought into contact with the lower portion of the supply roller 31 with an appropriate linear pressure. The presence of the receiving sheet prevents the toner adhering to the supply roller 31 from dropping due to gravity at the lower position, and prevents the toner that can be supplied to the developing roller from decreasing, thereby preventing a decrease in image density.
[0015]
The toner supplied to the developing roller 33 from the supply roller 31 scrapes off excess toner from the developing roller by the regulating blade 34 to regulate the amount of toner conveyed to the developing area and to appropriately charge the toner. I have to. The excess toner scraped off from the developing roller 33 by the regulation blade 34 is dropped by gravity, and a certain toner falls on the casing wall 45 below the regulation blade, and then slides down the wall to be returned to the toner accommodating portion 27. In addition, a certain toner directly falls and is returned to the toner storage unit 27. At this time, the angle formed with the horizontal line of the casing wall 45 is set to be larger than the repose angle of the toner. Then, the toner that is regulated by the regulating blade and appropriately charged is conveyed to the developing area facing the photosensitive member by the developing roller, and the electrostatic latent image portion on the photosensitive member is developed by the action of the vibration electric field described above. .
[0016]
After developing the electrostatic latent image formed on the photosensitive member in this manner, the upper seal 46 is brought into light contact with the developing roller 33 at a position where the toner remaining on the developing roller is returned to the developing device main body, thereby preventing leakage. ing. After development, the toner remaining on the developing roller 33 is separated from the surface of the developing roller by sliding between the developing roller and the developing roller 31 whose peripheral surface moves in the direction opposite to the developing roller at the contact portion, and is supplied to the toner receiving member 30. The toner is mixed with the toner accumulated in the gap (temporary storage unit) with the roller, and is supplied as new toner from the supply roller to the developing roller.
[0017]
In the experiment, a photoconductor drum having a diameter of 30 mm and a developing roller having a diameter of 18 mm was used, and the peripheral speed of the photoconductor was rotated at about 100 mm / s to 200 mm / s. About 1.5 to 2 times the peripheral speed. Moreover, as the supply roller, foamed urethane having a plurality of cells having an electric resistance of 10 ⁵ Ω · cm to 10 ⁶ Ω · cm, an Asker F hardness of 60 ° to 70 °, and a standard cell diameter of 100 to 150 μm. A material having a thickness of 2 to 4 mm was used, and a material having an elastic layer formed on the outer peripheral portion to a diameter of 15 to 18 mm was used. The regulating blade 34 has a conductive bronze rubber having a thickness of about 2 mm attached to the tip of a phosphor bronze plate or stainless plate having a thickness of about 0.15 mm. Further, the receiving sheet 32 and the conveying member 29a use PET films having a thickness of about 0.1 to 0.2 mm.
[0018]
According to the above configuration, when the toner scraped off by the regulating blade 34 is collected in the toner storage unit 27, the stress applied to the toner is eliminated by collecting the toner using the gravity or the angle of repose of the toner. The lifetime of the toner can be extended. For this reason, it is possible to reduce the white background stain and the density change due to the fogging of the toner and the decrease in the charge amount, and it is possible to maintain good image quality. Further, since the toner consumption is reduced, the running cost can be reduced.
[0019]
Further, in the toner storage portion, the center of the supply roller 31 is above the upper surface of the toner accumulation, and a scraper 30a (a sheet having a PET thickness of about 0.15 mm) is provided at the tip of the toner receiving member 30 below the supply roller. Is pasted. The toner shown in black in the drawing shows a state of being conveyed onto the scraper 30a. The scraper 30a is set so that the conveying member 29a attached to the tip of the stirring member 29 enters from and comes into contact with the scraper 30a and is pushed upward by the conveying member 29a to be deformed. Therefore, after the toner conveyed by the conveying member 29a is delivered to the scraper, the scraper is deformed upward, and the toner moves to a gap (temporary storage unit) between the toner receiving member 30 and the supply roller 31. At this time, the rotation direction of the agitating member 29 and the supply roller 31 is the reverse direction (therefore, the rotation direction of the conveying member 29a and the rotation direction of the supply roller 31 are also reverse directions). Then, the toner is supplied from the supply roller 31 to the developing roller. It is desirable that the conveying member 29a is conveyed along the inner wall of the container so that the tip of the conveying member 29a is in contact with the inner wall of the container, and the toner is delivered to the scraper. In addition, the angle between the scraper 30a and the horizontal line when attached to the toner receiving member is preferably equal to or greater than the repose angle of the toner. However, if the repose angle is less than the repose angle, the toner does not move to the temporary storage unit, Even if it remains, as described above, the scraper is deformed upward after the conveying member 29a contacts the scraper, so that in this state, the repose angle is exceeded and the toner moves to the temporary storage unit. .
[0020]
Since both the scraper 30a and the conveying member 29a are made of a resin sheet, the scraper 30a and the conveying member 29a have a property of being easily bent by stress, and as an appropriate use, the scraper 30a has a property of being more easily bent than the conveying member 29a. Is desirable. For this purpose, it is desirable to reduce the thickness of the scraper if the scraper and the conveying member are the same material, and to set the scraper to a low rigidity if the material is different. Thus, after sufficient toner is transferred from the conveying member to the scraper, the toner is supplied to the temporary storage unit without delay due to deformation of the scraper.
[0021]
On the other hand, in the roller shaft cross section, when a tangent line is drawn with respect to the conveyance member 29a at a position where the conveyance member 29a first contacts the toner receiving member 30, an angle between the tangent line and the horizontal line is θ2, and the toner receiving member 30 is When the angle formed with the horizon is θ1, it is preferable that θ1> θ2. If [theta] 1 <[theta] 2, the entrance angle (90 [deg.]-[Theta] 2) of the conveying member when the conveying member and the scraper come into contact with each other increases, and the scraper is prevented from being deformed smoothly, Overload more than necessary will shorten the life of the conveying member, and problems such as increasing the torque required to rotate the stirring member that fixes the conveying member will occur. . Furthermore, it is conceivable that a large noise is generated at the moment of contact. Therefore, it is preferable that θ1> θ2.
[0022]
Further, an angle θ3 formed by a line connecting the portion where the conveying member 29a first contacts the toner receiving member 30 and the rotation center of the stirring member 29 that fixes the conveying member and the vertical line is an angle θ3 in the rotation direction of the stirring member. When the angle is positive, 0 ≦ θ3 is preferable. If θ3 <0 is set, the toner at the end of the transport member may fall from the transport member or the scraper, and sufficient toner is not efficiently supplied to the temporary storage unit, resulting in insufficient supply. As a result, the image density is lowered. From the above, good toner supply can be achieved by appropriate arrangement and rigidity of the conveying member and the scraper.
[0023]
FIG. 2 is a diagram illustrating another embodiment of the developing device of the present invention.
This embodiment is characterized in that the developing roller is disposed below the photoconductor, and the other points are exactly the same as in the case of FIG. 1, and thus detailed description thereof is omitted. Also in the present embodiment, when the toner scraped off by the regulating blade 34 is collected in the toner container 27, the toner is collected by utilizing gravity or the angle of repose of the toner, thereby eliminating the stress applied to the toner. As a result, the life of the toner can be extended. As a result, it is possible to reduce white background stains and density changes due to toner fog and charge amount reduction, and maintain good image quality. Further, since the toner consumption is reduced, the running cost can be reduced.
In addition, a good supply of toner can be achieved by appropriate arrangement and rigidity of the conveying member and the scraper.
[0024]
FIG. 3 is a schematic cross-sectional view of an overall configuration showing an embodiment of an image forming apparatus to which the developing device of the present invention is applied. 1 is an image forming apparatus, 2 is a housing, 3 is a door, and 6 is exposure. Unit, 7 an image forming unit, 8 a cooling means, 9 a transfer belt unit, 10 a paper feeding unit, 11 a paper transport unit, 15 a cleaning means, 17 an image carrier, 18 an intermediate transfer belt, and 20 The developing means, 21 is a scanner means, 21b is a rotary polygon mirror, and 40 is a fixing means.
[0025]
In FIG. 3, the image forming apparatus 1 according to the present embodiment includes a housing 2, a paper discharge tray 2 a formed on the top of the housing 2, and a door body 3 that can be opened and closed on the front surface of the housing 2. An exposure unit (exposure means) 6, an image forming unit 7, a cooling means 8 including a blower fan, a transfer belt unit 9, and a paper feed unit 10 are disposed in the housing 2, and a paper transport unit is provided in the door 3. 11 is disposed. Each unit has a configuration that can be attached to and detached from the main body, and can be removed and repaired or replaced integrally during maintenance or the like.
[0026]
The image forming unit 7 includes a plurality (four in this embodiment) of image forming stations Y (for yellow), M (for magenta), C (for cyan), and K (for black) that form images of different colors. I have. Each of the image forming stations Y, M, C, and K has an image carrier (photoconductor) 17 formed of a photosensitive drum, and a charging unit including a corona charging unit disposed around the image carrier 17. The image forming stations Y, M, C, and K are arranged in parallel so that the image carrier 17 faces upward along an oblique arch-like line below the transfer belt unit 9. Is arranged. The order of arrangement of the image forming stations Y, M, C, and K is arbitrary.
[0027]
The transfer belt unit 9 is disposed below the housing 2 and is driven to rotate by a drive source (not shown), a driven roller 13 disposed obliquely above the drive roller 12, and a backup roller (tension roller). ) 14, an intermediate transfer belt 18 that is stretched between these three rollers and is circulated and driven in the direction indicated by the arrow (counterclockwise X), and a cleaning means 15 that contacts the surface of the intermediate transfer belt 18. ing. The driven roller 13, the backup roller 14, and the intermediate transfer belt 18 are arranged in a direction inclined to the left in the drawing with respect to the drive roller 12, so that the belt conveyance direction X when the intermediate transfer belt 18 is driven is downward. The surface 18a is positioned below, and the belt surface 18b whose conveying direction is upward is positioned above.
[0028]
Accordingly, the image forming stations Y, M, C, and K are also arranged in a direction inclined to the left in the drawing with respect to the driving roller 12. The image carrier 17 is pressed against a belt surface 18a facing downward in the transport direction of the intermediate transfer belt 18 along the arched line, and is rotationally driven in the transport direction of the intermediate transfer belt 18 as shown by the arrows in the figure. Since the flexible endless sleeve-shaped intermediate transfer belt 18 is pressed against the image carrier 17 so as to be covered from above, the pressure and nip width between the image carrier 17 and the intermediate transfer belt 18 are as follows. The tension can be adjusted by controlling the tension applied to the intermediate transfer belt 18 by the tension roller 14, the arrangement interval of the image carrier 17, the curvature of the arch, and the like.
[0029]
The drive roller 12 also serves as a backup roller for the secondary transfer roller 39. For example, a rubber layer having a thickness of about 3 mm and a volume resistivity of 10 ⁵ Ω · cm or less is formed on the peripheral surface of the drive roller 12, and the secondary transfer roller is grounded through a metal shaft. This is a conductive path for the secondary transfer bias supplied through the terminal 39. By providing the drive roller 12 with a rubber layer having high friction and shock absorption in this way, it is difficult for the impact when the recording medium enters the secondary transfer portion to be transmitted to the intermediate transfer belt 18, and deterioration of image quality is prevented. can do. Further, by making the diameter of the driving roller 12 smaller than the diameters of the driven roller 13 and the backup roller 14, the recording paper after the secondary transfer can be easily separated by the elastic force of the recording paper itself. Further, the driven roller 13 is also used as a backup roller for the cleaning means 15 described later.
[0030]
The intermediate transfer belt 18 is disposed in a direction inclined to the right in the drawing with respect to the driving roller 12, and correspondingly, each image forming station Y, M, C, K is also illustrated in the drawing with respect to the driving roller 12. You may arrange | position along the diagonal arch shape in the direction which inclines to the right side, ie, FIG.
[0031]
The cleaning unit 15 is provided on the side of the belt surface 18a facing downward in the transport direction, and a cleaning blade 15a that removes toner remaining on the surface of the intermediate transfer belt 18 after the secondary transfer, and a toner transport member that transports the collected toner 15b. The cleaning blade 15 a is in contact with the intermediate transfer belt 18 at a portion where the intermediate transfer belt 18 is wound around the driven roller 13. Further, a primary transfer member 16 is brought into contact with the back surface of the intermediate transfer belt 18 so as to face an image carrier 17 of each of image forming stations Y, M, C, and K described later. A transfer bias is applied.
[0032]
The exposure unit 6 is disposed in a space formed obliquely below the image forming unit 7 disposed in an oblique direction, and a cooling unit 8 is disposed in a space above the side surface of the exposure unit 6. A control unit and a power supply unit can be arranged on the side surface of the exposure unit 6 and the space below the cooling unit 8. A paper feeding unit 10 is disposed below the exposure unit 6 and at the bottom of the housing 2. The exposure means 6 is entirely housed in a case, and the case is disposed in a space formed obliquely below the belt surface facing downward in the transport direction. At the bottom of the case, a single scanner means 21 consisting of a polygon mirror motor 21a and a polygon mirror (rotating polygon mirror) 21b is arranged vertically to be exposed to the outside of the case from the bearing portion. A single f-θ lens 22 and a reflection mirror 23 are provided, and further, the scanning light paths y, m, c, and k of the respective colors are folded back to be non-parallel to the image carrier 17 above the reflection mirror 23. A plurality of folding mirrors 24 are arranged as described above.
[0033]
Since the polygon mirror motor 21a and the polygon mirror 21b are horizontally arranged in this manner, the force acting in the radial direction of the bearing can be eliminated, so that the number of rotations increases as the image forming apparatus increases in speed and resolution. Even when the load on the bearing increases, the heat generation of the bearing portion can be reduced, the temperature fluctuation in the apparatus can be reduced, and a high-quality image forming apparatus can be provided. Further, by providing the folding mirror 24, the scanning light paths y, m, c, and k can be bent, the height of the case can be reduced, and the size can be reduced. The folding mirror 24 is arranged so that the scanning optical path lengths to the image carrier 17 of the image forming stations Y, M, C, and K are the same.
[0034]
In the exposure means 6 having the above-described configuration, an image signal corresponding to each color is emitted from the polygon mirror 21b with a laser beam modulated and formed based on a common data clock frequency, and the f-θ lens 22, the reflection mirror 23, After passing through the folding mirror 24, the image carrier 17 of each image forming station Y, M, C, K is irradiated to form a latent image. In this way, the length of the optical path (optical path length) from the polygon mirror 21b of the exposure unit 6 to the image carrier 17 with respect to each image forming unit 7 is set to be substantially the same, thereby scanning in each optical path. The scanning widths of the emitted light beams are also substantially the same, and no special configuration is required for image signal formation. Therefore, the laser light source can be modulated and formed based on a common data clock frequency even though it is modulated corresponding to images of different colors by different image signals, and uses a common reflecting surface. Color misregistration caused by a relative difference in the sub-scanning direction can be prevented, and a simple and inexpensive color image forming apparatus can be configured.
[0035]
Further, in this embodiment, by arranging the scanning optical system below the apparatus, the vibration of the scanning optical system due to the vibration that the drive system of the image forming means gives to the frame that supports the apparatus can be minimized. Degradation of image quality can be prevented. In particular, by arranging the scanner means 21 at the bottom of the case, the vibration that the polygon motor 21a itself gives to the entire case can be minimized, and deterioration of the image quality can be prevented. Further, by making the number of polygon motors 21a, which are vibration sources, one, vibration applied to the entire case can be minimized.
[0036]
A cooling means 8 comprising a blower fan is provided on the side surface of the housing 2, and the internal air is guided in the direction of the arrow in the figure to release heat from the exposure means 6 and other heat generating portions. For this reason, the temperature rise of the polygon motor 21a can be suppressed, image quality deterioration can be prevented, and the life of the polygon motor 21a can be extended.
[0037]
In the present embodiment, the image stations Y, M, C, and K are arranged in an oblique direction, and the image carrier 17 is arranged in parallel upward along an oblique arch-shaped line. The toner storage container 26 is disposed obliquely downward so as to be pressed against the belt surface 18a facing downward in the transport direction.
[0038]
The developing means 20 employs a construction as shown in FIG. The developing means 20 has a developing roller exposed portion 20 a formed in the vicinity of the developing roller 33, while the corona charging means 19, which is a charging means, has an upward opening 19 a facing the image carrier 17. Has been. At this time, when the upward opening 19a of the corona charging unit 19 is located below the developing roller exposed part 20a, toner is spilled from the developing roller exposed part 20a due to gravity, and the corona charging unit 19 is exposed from the upward opening 19a of the corona charging unit 19. A problem arises that the corona charging means 19 is contaminated by entering the inside 19.
[0039]
Therefore, in this embodiment, the upward opening 19a is offset toward the intermediate transfer belt 18 so that the upward opening 19a of the corona charging unit 19 does not overlap the developing roller exposed part 20a of the developing unit 20. I have to. Accordingly, it is possible to solve the problem that the toner spills from the developing roller exposed portion 20a due to gravity and enters the corona charging means 19 from the upward opening 19a, thereby contaminating the corona charging means 19.
[0040]
The paper feeding unit 10 includes a paper feeding cassette 10a in which recording media P are stacked and held, and a pickup roller 36 that feeds recording media from the paper feeding cassette 10a one by one. The paper transport unit 11 includes a pair of gate rollers 37 (one roller is provided on the housing 2 side) that defines the timing of feeding the recording medium P to the secondary transfer unit, the driving roller 12 and the intermediate transfer belt 18. A secondary transfer roller 39 as a secondary transfer unit that is pressed against the main body, a main recording medium conveyance path, a fixing unit 40, a discharge roller pair 41, and a duplex printing conveyance path 42.
[0041]
The fixing means 40 includes at least one heating element such as a halogen heater incorporated therein and a rotatable fixing roller pair 40a, and at least one roller of the fixing roller pair 40a is pressed and urged to the other side. The secondary image secondarily transferred to the recording medium P is pressed to the recording medium P, and the secondary image secondarily transferred to the recording medium is at a predetermined temperature at the nip portion formed by the fixing roller pair 40a. It is fixed on the recording medium. In the present embodiment, the fixing unit 40 is disposed in a space formed obliquely above the belt surface 18b facing upward in the transfer belt conveyance direction, in other words, in a space opposite to the image forming station with respect to the transfer belt. Therefore, heat transfer to the exposure unit 6, the intermediate transfer belt 18, and the image forming unit can be reduced, and the frequency of performing the color misregistration correction operation for each color can be reduced. In particular, the exposure unit 6 is located farthest from the fixing unit 40, can minimize the displacement of the scanning optical system component due to heat, and can prevent color misregistration.
[0042]
In the present embodiment, since the intermediate transfer belt 18 is disposed in a direction inclined with respect to the drive roller 12, a wide space is formed in the right space in the figure, and the fixing means 40 is disposed in the space, and the developing roller And the image carrier 17 can be rotated so as to move in the same direction from the bottom to the top. Further, it is possible to prevent the heat generated in the fixing unit 40 from being transmitted to the exposure unit 6, the intermediate transfer belt 18 and the image forming stations Y, M, C, and K located on the left side. Further, since the exposure unit 6 can be arranged in the space on the lower left side of the image forming unit 7, the vibration of the scanning optical system of the exposure unit 6 due to the vibration applied to the housing 2 by the drive system of the image forming means is minimized. The image quality can be suppressed and deterioration of the image quality can be prevented.
[0043]
In this embodiment, the use of the spherical toner increases the primary transfer efficiency (approximately 100%), and each image carrier 17 is provided with a cleaning means for collecting the primary transfer residual toner. Not done. Thereby, it becomes possible to arrange each image carrier 17 composed of a photosensitive drum having a diameter of 30 mm or less close to each other, and the apparatus can be miniaturized.
[0044]
Further, the corona charging means 19 is adopted as the charging means in accordance with the absence of the cleaning means. When the charging unit is a roller, a small amount of primary transfer residual toner existing on the image carrier 17 accumulates on the roller to cause a charging failure, but the corona charging unit 19 which is a non-contact charging unit. Can prevent toner from adhering and can prevent charging failure.
[0045]
【The invention's effect】
As described above, according to the present invention, the developer receiving member is disposed below the developer supply member, and the developer is transported by contacting the developer receiving member when the developer transport member rotates. Further, since the rotation center of the developer supply member is located above the developer deposition upper surface, the supply of the developer to the developer supply member is smoothly performed without delay. Further, the remaining developer after the development is transported to the temporary storage portion in the gap between the developer receiving member and the developer supply member and used smoothly. In addition, since the developer that has been rotated is brought into contact with the developer receiving member and the developer that has been conveyed is delivered, stress applied to the developer can be reduced and the life of the developer can be extended. Further, the developer can be effectively supplied by appropriate arrangement and rigidity between the developer conveying member and the developer receiving portion.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an example of an embodiment of a developing device of the present invention.
FIG. 2 is a diagram illustrating an example of another embodiment of the developing device of the present invention.
FIG. 3 is a diagram illustrating an embodiment of an image forming apparatus using the developing device of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 17 ... Photoconductor, 20 ... Developing apparatus main body, 26 ... Toner storage container, 27 ... Toner container, 29 ... Toner stirring member, 29a ... Conveying member, 30 ... Toner receiving member, 30a ... Scraper, 31 ... Supply roller, 32 ... Receiving sheet, 33 ... Developing roller, 34 ... Regulating blade, 45 ... Case wall, 46 ... Upper seal.

Claims (6)

A developer container is formed in a direction in which the developer scraped off from the developer supply member that supplies the developer to the developer carrying member by gravity falls, and is provided below the developer supply member. A developer receiving member and a developer supply member, each having a flexible scraper attached thereto, form a developer temporary storage portion, and a developer agitating member rotatably provided in the developer accommodating portion A developing device configured to convey the developer from the developer accommodating portion to the temporary storage portion by the attached flexible developer conveying member;
The developer conveying member is rotated by the rotation of the developer agitating member, conveys the developer from the developer accommodating portion along the developer container wall surrounding the developer accommodating portion, and the tip side of the developer with respect to the scraper A developing device characterized in that the developer enters and abuts to deliver the developer.   2. The developing device according to claim 1, wherein the scraper is pushed upward and deformed by contact with the developer conveying member, and moves the transferred developer to the temporary storage unit.   The developing device according to claim 1, wherein the flexibility of the scraper is greater than the flexibility of the developer conveying member.   4. The developing device according to claim 1, wherein the rotation direction of the developer conveying member is opposite to the rotation direction of the developer supply member.   5. The developing device according to claim 1, wherein the developer carrying member is in contact with or close to the image carrying member from below.   An image forming apparatus comprising the developing device according to claim 1.

Images