Image forming device

Abstract

To provide a developing device that has a resin-made developer regulation member, and reduces the amount of toner scattering to the outside of a developer container from both ends in the rotation axis direction of a developing rotating body.SOLUTION: A sheet member is provided over the entire area of a developing rotating body corresponding to the maximum image area of an image carrier where an image can be formed. A space enclosed by the developing rotating body, a developer regulation member, and the sheet member is formed over the entire area of the developing rotating body corresponding to the maximum image area. On the outside of the area of the developing rotating body corresponding to the maximum image area in the rotation axis direction of the developing rotating body, the developer regulation member is provided with a first sealing part and a second sealing part at positions corresponding to one end and the other end in the rotation axis direction of the developing rotating body. On the outside of the area of the developing rotating body corresponding to the maximum image area in the rotation axis direction of the developing rotating body, the first sealing part covers one end in the longitudinal direction of the space, and the second sealing part covers the other end in the longitudinal direction of the space.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus equipped with a developing device having a developer regulating member made of resin. [Background technology]

[0002] The developing device includes a developer container that contains a developer containing toner and a carrier, and a developing rotor that carries and transports the developer to a development area where an electrostatic image formed on an image carrier is developed. While the developing device is operating, air flows into the developer container as the developing rotor rotates. In particular, when the rotational speed of the developing rotor is increased to increase the process speed, the amount of air flowing into the developer container per unit time increases, resulting in a greater increase in the internal pressure within the developer container. When the internal pressure within the developer container increases, the force of the air attempting to be expelled from the developer container to the outside of the developer container through the opening of the developer container increases, which tends to increase the amount of toner that scatters from the developer container to the outside of the developer container.

[0003] In recent years, a developing device has become known that has a resin-made developer regulating member that regulates the amount of developer carried on the surface of a developing rotor, the developer regulating member being molded from resin (see Patent Document 1). The resin-made developer regulating member described in Patent Document 1 has a sheet member attached to it that is disposed facing the developing rotor in a non-contact manner and that seals at least a portion of the space formed between the developing device and the image carrier. This sheet member is provided facing the developing rotor across the entire area of ​​the developing rotor (maximum image area of ​​the developing rotor) that corresponds to the maximum image area of ​​the image area in which an image can be formed on the surface of the image carrier, in the direction of the rotation axis of the developing rotor. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-101304 Summary of the Invention [Problem to be solved by the invention]

[0005] The configuration of Patent Document 1 can prevent toner from scattering outside the developer container in the maximum image area of ​​the developing rotor when the developer regulating member regulates the thickness of the developer layer passing through the gap between the developing rotor and a resin developer regulating member. However, in the configuration of Patent Document 1, the sheet member is not provided outside the maximum image area of ​​the developing rotor in the direction of the rotational axis of the developing rotor. This means that air tends to move laterally inside the developing container from the center to the ends along the rotational axis of the developing rotor. The more air in the developing container moves laterally from the center to the ends along the rotational axis of the developing rotor, the more likely it is that toner-containing air will be discharged outside the developing container from both ends along the rotational axis of the developing rotor. As a result, there is a risk of a large amount of toner scattering outside the developing container from both ends along the rotational axis of the developing rotor.

[0006] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a developing device having a resin developer regulating member, which is configured to reduce the amount of toner scattered outside the developing container from both ends of the developing rotor in the rotational axis direction. [Means for solving the problem]

[0007] In order to achieve the above object, an image forming apparatus according to one aspect of the present invention comprises the following configuration: a rotatable image carrier on which an electrostatic image is formed, an exposure device that exposes the image carrier to light in order to form an electrostatic image on the image carrier, a developer container that contains a developer including toner and a carrier, a developing rotor that carries and transports the developer in order to develop the electrostatic image formed on the image carrier, a developer regulating member made of resin that is disposed opposite to the developing rotor in a non-contact manner and that regulates the amount of developer carried on the developing rotor, and a developer regulating member that is disposed opposite to the developing rotor downstream in the rotation direction of the developing rotor from a position on the developing rotor that is closest to the developer regulating member and upstream in the rotation direction of the developing rotor from a position on the developing rotor that is closest to the image carrier, a sheet member provided on the developer regulating member, wherein a position on the developing rotary body where the developing rotary body is closest to the developer regulating member is lower than a position on the developing rotary body where the developing rotary body is closest to the image carrier, the sheet member is provided over the entire area of ​​the developing rotary body corresponding to the maximum image area on which an image can be formed on the image carrier, and a space partitioned by the developing rotary body, the developer regulating member, and the sheet member is formed over the entire area of ​​the developing rotary body corresponding to the maximum image area, and the developer regulating member is provided on the outer side in the direction of the rotation axis of the developing rotary body than the area of ​​the developing rotary body corresponding to the maximum image area. The developing rotary body is formed in a substantially concentric shape on the developing rotary body from a position on the developing rotary body closest to the developer regulating member toward the downstream in the rotation direction of the developing rotary body. The first sealing portion facing one end of the developing rotor in the rotational axis direction without contacting it It is provided, and The developing rotary body is formed in a substantially concentric shape on the developing rotary body from a position on the developing rotary body closest to the developer regulating member toward the downstream in the rotation direction of the developing rotary body. The second sealing portion The developing rotor is opposed to the other end of the developing rotor in the direction of the rotation axis without contacting the other end. The first sealing portion covers one end of the space in the longitudinal direction, and the second sealing portion covers the other end of the space in the longitudinal direction, outside the area of ​​the developing rotor corresponding to the maximum image area in the direction of the rotation axis of the developing rotor. [Effects of the Invention]

[0008] According to the present invention, in a developing device having a developer regulating member made of resin, the amount of toner scattered outside the developing container from both ends of the developing rotor in the rotational axis direction can be reduced. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view showing the overall configuration of an image forming apparatus according to a first embodiment. [Figure 2] FIG. 2 is a perspective view showing the configuration of a developing device according to the first embodiment. [Figure 3] FIG. 2 is a cross-sectional view showing the configuration of the developing device according to the first embodiment. [Figure 4] FIG. 2 is a cross-sectional view showing a configuration in the vicinity of a regulating blade according to the first embodiment. [Figure 5] FIG. 10 is a diagram showing a state in which scattered toner has accumulated near the regulating blade according to the first embodiment. [Figure 6] 3 is a perspective view showing the configuration of a pair of sealing portions provided on the regulating blade according to the first embodiment. FIG. [Figure 7] FIG. 10 is a perspective view showing the configuration of a pair of sealing portions provided on a regulating blade according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the present invention, and not all of the combinations of features described in the embodiments are necessarily essential to the solution of the present invention. The present invention can be implemented in a variety of applications, such as printers, various printing machines, copiers, fax machines, and multifunction machines.

[0011] [First embodiment] (Overall configuration of image forming apparatus) First, the overall configuration of an image forming apparatus according to a first embodiment of the present invention will be described using the cross-sectional view of Fig. 1. Fig. 1 is a cross-sectional view of a color image forming apparatus using an electrophotographic system, and the image forming apparatus 60 is an example of a so-called intermediate transfer tandem system in which four color image forming units 600 are arranged facing an intermediate transfer belt 61.

[0012] The transfer material S is stored in a stacked form in a transfer material storage section 62, and is fed by feeding means 63 in accordance with the image formation timing. Here, feeding means 63 uses a friction separation method using a feeding roller or the like. The transfer material S sent out by feeding means 63 is conveyed to registration rollers 65 arranged midway along a conveying path 64. After skew correction and timing correction are performed by registration rollers 65, the transfer material S is sent to a secondary transfer section. The secondary transfer section is a transfer nip section formed by opposing secondary transfer inner roller 66 and secondary transfer outer roller 67, and a toner image is attracted to the transfer material S by applying a predetermined pressure force and an electrostatic load bias.

[0013] The image formation process for the transfer material S, which is transported to the secondary transfer unit at the same timing as the above-described process for transporting the transfer material S to the secondary transfer unit, will now be described. The image forming unit 600 is primarily composed of a photosensitive drum 1 (image carrier), a developing device 2, a charging device 3, a primary transfer device 4, and a photosensitive cleaner 5. The surface of the rotating photosensitive drum 1 is uniformly charged in advance by the charging device 2, and then an electrostatic latent image (electrostatic image) is formed on the surface by an exposure device 68 driven based on image information signals. The electrostatic latent image formed on the photosensitive drum 1 is then visualized through toner development by the developing device 2. The primary transfer device 4 then applies a predetermined pressure and electrostatic load bias, transferring the toner image onto the intermediate transfer belt 61. Finally, the photosensitive cleaner 5 collects any residual toner remaining on the photosensitive drum 1, preparing it for the next image formation process. 1, there are four sets of image forming units 600 described above: yellow (Y), magenta (M), cyan (C), and black (Bk). However, the number of colors is not limited to four, and the order of the colors is not limited to this.

[0014] Next, the intermediate transfer belt 61 will be described. The intermediate transfer belt 61 is an endless belt stretched by a tension roller 6, a secondary transfer inner roller 66, and driven rollers 7a and 7b, and is driven to be transported in the direction of arrow C in FIG. 1. The secondary transfer inner roller 66 also serves as a drive roller that drives the intermediate transfer belt 61. The image formation processes for each color, Y, M, C, and Bk, are performed in parallel by the image forming units 600, and are timed to be sequentially superimposed on the toner images of the upstream colors that have been primarily transferred onto the intermediate transfer belt 61. As a result, a full-color toner image is finally formed on the intermediate transfer belt 61 and transported to the secondary transfer unit. Residual toner remaining after passing through the secondary transfer unit is collected by a transfer cleaner device 8.

[0015] Through the transport process and image creation process described above, the timing of the transfer material S and the full-color toner image is synchronized at the secondary transfer section, and secondary transfer is performed. The transfer material S is then transported to the fixing device 9, where the toner image is fused and fixed to the transfer material S using a predetermined amount of pressure and heat. The transfer material S, with the image fixed in this manner, is either discharged directly onto the discharge tray 601 by the forward rotation of the discharge rollers 69, or a double-sided image is formed on the transfer material S. If double-sided image formation is required, the forward rotation of the discharge rollers 69 transports the transfer material S until its trailing edge passes through a switching flapper 602, and then the reverse rotation of the discharge rollers 69 switches the leading and trailing edges, and the transfer material is transported to the double-sided transport path 603. The transfer material S is then transported again to the transport path 64 by the re-feed rollers 604 in time with the transfer material S of the subsequent job being transported by the feed means 63. The subsequent transport and the image creation process on the back side of the transfer material S are the same as those for the front side of the transfer material S described above, and therefore will not be described here.

[0016] (Configuration of developing device) Next, the configuration of the developing device 2 according to the first embodiment will be described with reference to the perspective view of FIG. 2 and the cross-sectional view of FIG.

[0017] The developing container 20 contains a two-component developer (hereinafter simply referred to as developer) containing toner and carrier. The developing container 20 has an opening in a portion facing the photosensitive drum 1, and a developing sleeve 21 (developer carrier, developing rotor) is rotatably disposed so that it is partially exposed through this opening. The developing sleeve 21 carries and transports the developer to a development area where an electrostatic latent image formed on the surface of the photosensitive drum 1 is developed. The developing sleeve 21 is made of a non-magnetic material, and a magnet 22 serving as a magnetic field generating means is disposed inside the developing sleeve 21 in a non-rotatable, fixed manner.

[0018] A regulating blade 23 (developer regulating member) that regulates the amount of developer carried on the developing sleeve 21 (on the developing rotor) is attached to the developing container 20. In the first embodiment, as shown in FIG. 3, the position on the developing sleeve 21 where the developing sleeve 21 is closest to the regulating blade 23 is lower than the position on the developing sleeve 21 where the developing sleeve 21 is closest to the photosensitive drum 1.

[0019] The regulating blade 23 is molded from resin and has sufficient rigidity to be bent. The regulating blade 23 is adhered to the developing container 20 using an adhesive in a bent state so that the gap (shortest distance) between the developing sleeve 21 and the regulating blade 23 falls within a predetermined range.

[0020] The developing sleeve 21 rotates in the direction of arrow E in Figure 3, transporting the developer toward the regulating blade 23. The developer is subjected to shearing force by the regulating blade 23, which regulates its amount, and as it passes through the gap between the developing sleeve 21 and the regulating blade 23, it forms a developer layer of a predetermined thickness on the developing sleeve 21. The developer layer formed on the developing sleeve 21 is carried and transported to a development area facing the photosensitive drum 1, where it develops the electrostatic latent image formed on the surface of the photosensitive drum 1.

[0021] The developing container 20 is partitioned by a partition wall 15 into a developing chamber 11 (first developer storage chamber) and an agitating chamber 12 (second developer storage chamber). The developing chamber 11 and the agitating chamber 12 extend along the rotational axis direction of the developing sleeve 21. Both ends of the partition wall 15 do not reach the side walls at both longitudinal ends of the interior of the developing container 20, thereby forming communication openings as communication portions that allow the developer to pass between the developing chamber 11 and the agitating chamber 12. A first screw 13 is disposed in the developing chamber 11 as a circulating and transporting member that circulates the developer between the developing chamber 11 and the agitating chamber 12. A second screw 14 is disposed in the agitating chamber 12 as a circulating and transporting member that circulates the developer between the developing chamber 11 and the agitating chamber 12.

[0022] The developing sleeve 21, the first screw 13, and the second screw 14 are each configured to be connected and driven by a gear train, and rotate by receiving driving force from a drive gear provided in the developing device 2. Then, by the rotation of the first screw 13 and the second screw 14, the developer is mixed and stirred while circulating inside the developing container 20.

[0023] The replenishment toner is supplied from a supply port 17 provided at the most upstream position in the developer transport direction of the second screw 14. The replenishment toner supplied from the supply port 17 is transported into the stirring chamber 12 by the second screw 14, and then stirred and mixed with the developer, so that the toner is uniformly dispersed in the developer while being triboelectrically charged.

[0024] The replenishment toner supplied from the supply port 17 is uniformly dispersed in the developer while being triboelectrically charged, and then the thickness of the developer layer passing through the gap between the developing sleeve 21 and the regulating blade 23 is regulated by the regulating blade 23. When toner with a low charge amount passes through the regulating blade 23, as the thickness of the developer layer is regulated by the regulating blade 21, the toner separates from the carrier due to centrifugal force caused by the rotation speed of the developing sleeve 21 and force caused by the movement of the carrier magnetic chains on the developing sleeve 21. When the toner separates from the carrier, there is a risk that the toner will scatter outside the developing container 20.

[0025] Furthermore, while the developing device 2 is operating, air flows into the developing container 20 as the developing sleeve 21 rotates. In particular, when the rotational speed of the developing sleeve 21 is increased to increase the process speed, the amount of air flowing into the developing container 20 per unit time increases, and the degree to which the internal pressure in the developing container 20 increases increases. When the internal pressure in the developing container 20 increases, the force of the air attempting to be discharged from inside the developing container 20 to the outside of the developing container 20 through the opening of the developing container 20 increases, and therefore the amount of toner scattering from inside the developing container 20 to the outside of the developing container 20 tends to increase.

[0026] 3, a sheet member 24 for suppressing toner scattering is attached to the resin regulating blade 23. Specifically, the sheet member 24 is provided facing the developing sleeve 21 over the entire area of ​​the developing sleeve 21 corresponding to the maximum image area among the image areas in which an image can be formed on the surface of the photosensitive drum 1, in the direction of the rotation axis of the developing sleeve 21. In the first embodiment, if the sheet member 24 is provided over 95% or more of the area of ​​the developing sleeve 21 corresponding to the maximum image area, it is considered that the sheet member 24 is provided over the entire area of ​​the developing sleeve 21 corresponding to the maximum image area.

[0027] Here, the configuration in the vicinity of the resin regulating blade 23 will be described with reference to the cross-sectional view of Fig. 4. The sheet member 24 is a 100 µm thick urethane sheet, and is attached to the resin regulating blade 21 via a resin sheet attachment base 25 provided on the resin regulating blade 21 so as to form a predetermined angle on the regulating blade 23 with double-sided tape or adhesive. Note that, in the first embodiment, an example will be described in which the resin regulating blade 23 and the resin sheet attachment base 25 are integrally molded, but a modified example in which the resin regulating blade 23 and the resin sheet attachment base 25 are separate bodies may also be used.

[0028] The sheet member 24 is located downstream in the rotation direction of the developing sleeve 21 from the position (regulating position) of the regulating blade 23 at which it is closest to the developing sleeve 21, and upstream in the rotation direction of the developing sleeve 21 from the position (developing position) at which the developing sleeve 21 is closest to the photosensitive drum 1. As a result, the sheet member 24 is disposed so as to seal the regulating blade 23 from the photosensitive drum 1. The other end of the sheet member 24 is attached to a sheet attachment base 25 so that the gap between the sheet member 24 and the developing sleeve 21 narrows from the upstream to downstream in the rotation direction of the developing sleeve 21. The other end of the sheet member 24 is attached to the sheet attachment base 25 so that one end in the width direction of the sheet member 24 contacts the developing sleeve 21.

[0029] Here, the state when toner accumulates near the resin regulating blade 23 will be described with reference to the cross-sectional view of Fig. 5. Also, the configuration of a pair of sealing portions provided on the regulating blade 23 according to the first embodiment will be described with reference to the perspective view of Fig. 6.

[0030] 6, a space F partitioned by the developing sleeve 21, the regulating blade 23, and the sheet member 24 is formed over the entire area R of the developing sleeve 21, which corresponds to the maximum image area among the image areas in which an image can be formed on the surface of the photosensitive drum 1. In the first embodiment, if the space F is formed over 95% or more of the area R of the developing sleeve 21, which corresponds to the maximum image area, it is considered that the space F is formed over the entire area of ​​the area R of the developing sleeve 21, which corresponds to the maximum image area.

[0031] 5 and 6, toner that has been liberated from the developer when it passes through the gap between the developing sleeve 21 and the regulating blade 23 and toner that has been liberated from the developer on the developing sleeve 21 accumulate in the space F. When the toner layer of the developer that has accumulated in the space F grows to a certain amount, air moves horizontally inside the developing container 20 from the center to the ends in the direction of the rotation axis of the developing sleeve 21.

[0032] The greater the amount of air moving laterally from the center of the developing sleeve 21 toward the ends of the developing sleeve 21 in the axial direction, the more easily the air containing accumulated toner is expelled from the developing sleeve 21 in the axial direction. Furthermore, as the developing sleeve 21 rotates, air passes through the regulating position and flows into the enclosed space F from within the developing sleeve 20. This air then flows longitudinally, potentially increasing the amount of toner scattered from both ends of the developing sleeve 21 in the axial direction to the outside of the developing container 20. As a result, toner scattered from both ends of the developing sleeve 21 in the axial direction to the outside of the developing container 20 may be carried by the airflow and adhere to the photosensitive unit, including the photosensitive drum 1. In recent years, for ease of service, photosensitive units and other components are often installed in image forming apparatuses 60 in a user-replaceable form. In such a configuration, if scattered toner adheres to the photosensitive unit, a user may come into contact with the toner and become contaminated when replacing the photosensitive unit.

[0033] In the first embodiment, the regulating blade 23 is made of resin, and a pair of sealing portions 26 (first sealing portion, second sealing portion) are provided on the regulating blade 23 as a configuration capable of reducing the amount of toner scattering outside the developer container 20 from both ends of the developing sleeve 21 in the rotational axis direction. Specifically, the sheet member 24 is provided over the entire region R of the developing sleeve 21, which corresponds to the maximum image area where an image can be formed on the photosensitive drum 1. A space F is formed over the entire region R of the developing sleeve 21, which corresponds to the maximum image area, and is partitioned by the developing sleeve 21, the regulating blade 23, and the sheet member 24. Further, the regulating blade 23 is provided with a pair of sealing portions 26 at positions facing one end and the other end of the developing sleeve 21 in the rotational axis direction, outside the region R of the developing sleeve 21 corresponding to the maximum image area in the rotational axis direction of the developing sleeve 21. Further, outside the region R of the developing sleeve 21 corresponding to the maximum image area in the direction of the rotation axis of the developing sleeve 21, the sealing portion 26 (first sealing portion) covers one end of the space F in the longitudinal direction, and the sealing portion 26 (second sealing portion) covers the other end of the space F in the longitudinal direction. In the first embodiment, the developing device 2 is provided with a regulating blade 23 made of resin, which reduces the amount of toner that scatters outside the developing container 20 from both ends of the developing sleeve 21 in the direction of the rotation axis. Details thereof will be described below.

[0034] 6, sealing portions 26 are provided at both ends in the longitudinal direction of the resin regulating blade 23. Specifically, in the first embodiment, the pair of sealing portions 26 are fixed to the resin regulating blade 23 or the resin sheet attachment base 25 with double-sided tape or adhesive. Also, in the first embodiment, the thickness of the pair of sealing portions 26 in the direction of the rotation axis of the developing sleeve 21 is set to about 1 mm to 2 mm, which is the general thickness of a resin part, but the thickness is not limited to this and may be greater.

[0035] The sealing portions 26 are provided at both ends of the developing sleeve 21 in the direction of its rotation axis, and prevent toner from scattering in the longitudinal direction of the space F surrounded by the regulating blade 23, the developing sleeve 21, and the sheet member 24.

[0036] The sealing portion 26 is formed approximately concentrically with the developing sleeve 21 from the position (regulating position) where the regulating blade 23 and the developing sleeve 21 are closest to each other toward the downstream side in the rotation direction of the developing sleeve 21, with a small gap between the developing sleeve 21 and the sealing portion 26. The gap (shortest distance) between the outer peripheral surface of the developing sleeve 21 and the outer peripheral surface of the sealing portion 26 is preferably 100 μm or more and 500 μm or less.

[0037] This is because, if the gap between the outer peripheral surface of the developing sleeve 21 and the outer peripheral surface of the sealing portion 26 is smaller than 100 μm, there is a possibility that the developing sleeve 21 and the sealing portion 26 may come into contact with each other, depending on the assembly accuracy and component tolerances. If the sealing portion 26 comes into contact with the developing sleeve 21, there is a risk that the temperature of the contacting portion between the developing sleeve 21 and the sealing portion 26 may rise.

[0038] On the other hand, if the gap between the outer peripheral surface of the developing sleeve 21 and the outer peripheral surface of the sealing portion 26 is larger than 500 μm, less of the space F is covered at each of the longitudinal ends of the space F partitioned by the developing sleeve 21, the regulating blade 23, and the sheet member 24. As a result, the effect of suppressing the lateral movement of air inside the developing container 20 from the center toward the ends in the rotational axis direction of the developing sleeve 21 is reduced.

[0039] Therefore, the gap between the outer peripheral surface of the developing sleeve 21 and the outer peripheral surface of the sealing portion 26 is appropriately selected in consideration of assembly accuracy and component tolerances. In the first embodiment, the component tolerances and mounting accuracy of the developing sleeve 21 are taken into consideration, and the gap (shortest distance) between the outer peripheral surface of the developing sleeve 21 and the outer peripheral surface of the sealing portion 26 is set to about 200 μm. In addition, the opposing surface of the sheet member 24 is also formed with a small gap approximately parallel to the sheet member 24. From the viewpoint of preventing toner scattering, it is preferable to reduce these gaps as much as possible in terms of assembly and component tolerances.

[0040] Furthermore, in the first embodiment, the material of the pair of sealing portions 26 is selected from ABS, a common resin material, but this is not limited thereto, and a modified example in which an elastic material such as a sponge is used may also be used. When an elastic material such as a sponge is used for the pair of sealing portions 26, the pair of sealing portions 26 can be used in contact with the developing sleeve 21. This is because, when an elastic material such as a sponge is used for the pair of sealing portions 26, even if the developing sleeve 21 and the sealing portions 26 come into contact with each other, there is no risk of the temperature of the contacting portions between the developing sleeve 21 and the sealing portions 26 rising.

[0041] When an elastic body such as a sponge is used for the pair of sealing portions 26, the gap between the outer peripheral surface of the developing sleeve 21 and the outer peripheral surface of the sealing portions 26 becomes substantially zero, thereby enhancing the effect of covering each of one end and the other end in the longitudinal direction of the space F. If the effect of covering each of one end and the other end in the longitudinal direction of the space F is enhanced, the effect of suppressing the lateral movement of air inside the developing container 20 from the center toward the ends in the rotational axis direction of the developing sleeve 21 can be enhanced. However, since the developing sleeve 21 and the sealing portions 26 are in contact with each other, from the viewpoint of the wear resistance (lifespan) of the elastic body, it goes without saying that a configuration in which the developing sleeve 21 and the sealing portions 26 do not come into contact with each other is preferable to a configuration in which the developing sleeve 21 and the sealing portions 26 come into contact with each other.

[0042] 6, a space F is formed across the entire region R of the developing sleeve 21, which corresponds to the largest image region among the image regions capable of forming an image on the surface of the photosensitive drum 1, and is partitioned by the developing sleeve 21, the regulating blade 23, and the sheet member 24. A pair of sealing portions 26 (first sealing portion, second sealing portion) are disposed at one end and the other end of the developing sleeve 21 in the longitudinal direction, which are located outside the region where the developing sleeve 21 has the developer transport capacity. This allows the pair of sealing portions 26 to cover the one end and the other end of the space F in the longitudinal direction, which is partitioned by the developing sleeve 21, the regulating blade 23, and the sheet member 24.

[0043] The region where the developing sleeve 21 has the developer transport capability is the region R corresponding to the largest image region among the image regions where an image can be formed on the surface of the photosensitive drum 1. The region where the developing sleeve 21 has the developer transport capability is the region where the magnet 22 is provided inside the developing sleeve 21 and where the outer peripheral surface of the developing sleeve 21 has been subjected to surface processing (for example, grooves, excavations, blasting, etc.) that allows carrier to be held.

[0044] If the sealing portions 26 are arranged in the region R corresponding to the maximum image region among the image regions in which an image can be formed on the surface of the photosensitive drum 1, the layer thickness (coat amount) of the developer carried on the developing sleeve 21 may change due to contact with the sealing portions 26, which may affect the electrostatic latent image. Therefore, in order to eliminate any effect on the electrostatic latent image, the pair of sealing portions 26 are not arranged in the region R in which the developing sleeve 21 has the developer transport capacity, but are arranged at one end and the other end of the developing sleeve 21 on the outer side in the longitudinal direction than the region R in which the developing sleeve 21 has the developer transport capacity.

[0045] As described above, in the first embodiment, in the developing device including the resin regulating blade 23, a pair of sealing portions 26 are provided at the longitudinal ends of the regulating blade 23. In the first embodiment, such a configuration can reduce the amount of toner that scatters outside the developing container 20 from the end of the developing sleeve 21 in the rotational axis direction.

[0046] [Second embodiment] In the second embodiment, differences from the first embodiment will be described, but other basic configurations are common to the first and second embodiments. In the configuration of the first embodiment described above, an example was described in which the pair of sealing portions 26 are fixed to the resin regulating blade 23 or the resin sheet attachment base 25 with double-sided tape or adhesive. On the other hand, in the configuration of the second embodiment, the pair of sealing portions 26a and the regulating blade 23a are formed from the same part. In other words, in the first embodiment, the regulating blade 23 and the pair of sealing portions 26 are separate bodies, whereas in the second embodiment, the regulating blade 23a and the pair of sealing portions 26a are integrally molded from resin.

[0047] The regulating blade 23a is attached with a gap (the shortest distance between the developing sleeve 21 and the regulating blade 23a) adjusted with high precision to obtain a developer layer of a predetermined thickness on the developing sleeve 21. The adjustment precision of the gap between the developing sleeve 21 and the regulating blade 23a is ±20 to 50 μm.

[0048] In the second embodiment, similarly to the first embodiment, the regulating blade 23a is made of resin and has sufficient rigidity to be bent. The regulating blade 23a is adhered to the developing container 20 with an adhesive in a bent state so that the gap (shortest distance) between the developing sleeve 21 and the regulating blade 23a falls within a predetermined range.

[0049] In the second embodiment, the regulating blade 23a and the pair of sealing portions 26a are integrally molded from resin. In the second embodiment, the regulating blade 23a is attached to the developing container 20 so that the gap between the developing sleeve 21 and the regulating blade 23a falls within a predetermined range, thereby enabling high-precision assembly of the pair of sealing portions 26a and the developing sleeve 21. In order to enhance the effect of suppressing lateral movement of air inside the developing container 20 from the center toward the ends in the rotational axis direction of the developing sleeve 21, it is preferable that the gap (shortest distance) between the outer circumferential surface of the developing sleeve 21 and the outer circumferential surface of the sealing portions 26a be 100 μm or more and 500 μm or less.

[0050] In the second embodiment, the regulating blade 23a and the pair of sealing portions 26a are integrally molded from resin, which enables the pair of sealing portions 26a and the developing sleeve 21a to be assembled with high precision. Furthermore, in the second embodiment, the regulating blade 23a, the sheet attachment base 25a, and the pair of sealing portions 26a are integrally molded from resin. Therefore, in the second embodiment, the gap (shortest distance) between the outer peripheral surface of the developing sleeve 21 and the outer peripheral surface of the sealing portions 26a can be set smaller than in the first embodiment, in which the regulating blade 23a and the pair of sealing portions 26a are separate bodies.

[0051] In the second embodiment, the gap (shortest distance) between the outer peripheral surface of the developing sleeve 21 and the outer peripheral surface of the sealing portion 26a is set to about 100 μm, which enhances the effect of suppressing the lateral movement of air inside the developing container 20 from the center toward the ends in the rotational axis direction of the developing sleeve 21. Therefore, in the second embodiment, it is possible to enhance the effect of suppressing toner scattering from both ends in the rotational axis direction of the developing sleeve 21.

[0052] The configuration of the second embodiment (the configuration in which the regulating blade 23a and the pair of sealing portions 26a are integrated) improves the accuracy of the gap between the developing sleeve 21 and the pair of sealing portions 26a compared to the configuration of the first embodiment (the configuration in which the regulating blade 23 and the pair of sealing portions 26 are separate). In this respect, the second embodiment is advantageous over the first embodiment.

[0053] On the other hand, in the configuration of the second embodiment in which the resin regulating blade 23a and the pair of sealing portions 26a are integrally molded, it is necessary to suppress sink marks and the like with respect to the thickness of the pair of sealing portions 26a. Therefore, in the second embodiment, it is desirable to set the thickness of the pair of sealing portions 26a in the form of ribs so as to be close to the basic thickness of the regulating blade 23a in order to suppress sink marks and the like, or to provide appropriate cutouts.

[0054] (Other embodiments) The present invention is not limited to the above-described embodiments, and various modifications (including organic combinations of the respective embodiments) are possible based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

[0055] In the above embodiment, an image forming apparatus configured to use an intermediate transfer belt 61 as shown in Fig. 1 has been described as an example, but the present invention is not limited to this. It is also possible to apply the present invention to an image forming apparatus configured to perform transfer by directly contacting the transfer material S with the photosensitive drum 1 in sequence. [Explanation of symbols]

[0056] 1 Photosensitive drum 2. Developing device 20 Developer container 21 Developing sleeve 22 Developing sleeve 23 Regulatory Blade 24 Sheet material 26 Sealing part 60 Image forming device 68 Exposure equipment

Claims

1. a rotatable image carrier on which an electrostatic image is formed; an exposure device that exposes the image carrier to light to form an electrostatic image on the image carrier; a developing device including: a developing container that contains a developer containing toner and a carrier; a developing rotor that carries and transports the developer to develop an electrostatic image formed on the image carrier; a resin developer regulating member that is disposed opposite the developing rotor without contacting the developing rotor and that regulates the amount of developer carried on the developing rotor; and a sheet member that is disposed opposite the developing rotor downstream in the rotation direction of the developing rotor from a position on the developing rotor where the developing rotor is closest to the developer regulating member and upstream in the rotation direction of the developing rotor from a position on the developing rotor where the developing rotor is closest to the image carrier, and that is provided on the developer regulating member; Equipped with a position on the developing rotary body where the developing rotary body is closest to the developer regulating member is lower than a position on the developing rotary body where the developing rotary body is closest to the image carrier; the sheet member is provided over the entire area of ​​the developing rotary body corresponding to the maximum image area on the image carrier where an image can be formed, a space partitioned by the developing rotary body, the developer regulating member, and the sheet member is formed over the entire area of ​​the developing rotary body corresponding to the maximum image area, a first sealing portion formed in a substantially concentric shape on the developing rotor from a position on the developing rotor where the developing rotor is closest to the developer regulating member toward the downstream in the rotational direction of the developing rotor, the first sealing portion being provided in opposition to one end of the developing rotor in the rotational direction in a non-contact manner, outside a region of the developing rotor corresponding to the maximum image area, the first sealing portion being formed in a substantially concentric shape on the developing rotor from a position on the developing rotor where the developing rotor is closest to the developer regulating member toward the downstream in the rotational direction of the developing rotor, the first sealing portion being provided in opposition to one end of the developing rotor in the rotational direction in a non-contact manner, The first sealing portion covers one end of the space in the longitudinal direction, and the second sealing portion covers the other end of the space in the longitudinal direction, on the outer side of a region of the developing rotor corresponding to the maximum image area. An image forming apparatus characterized by:

2. The developer regulating member, the first sealing portion, and the second sealing portion are integrally molded.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

3. The shortest distance between the developing rotor and the first sealing portion is 100 μm or more and 500 μm or less, and the shortest distance between the developing rotor and the second sealing portion is 100 μm or more and 500 μm or less.

3. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

4. The developer regulating member has a rigidity that allows it to bend.

4. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

Images