Developing apparatus and image forming system

Abstract

Compared to a configuration where the entire area of ​​the gap formed between the developing element and the housing is covered by a covering element, this configuration suppresses the rise in internal pressure of the housing. [Solution] The developing apparatus comprises a housing that houses a developer and has an opening opposite to an image holder capable of holding a latent image; a developing member that is rotatably provided inside the housing, exposed from the opening, capable of holding the developer on its outer circumference, and develops the latent image with the held developer while rotating; and a covering member that covers the gap between the developing member and the housing downstream of the developing position in the rotational direction of the developing member, the covering member covering a first region in the gap corresponding to one end of the developing member in the rotational direction, and not covering at least a part of an intermediate region corresponding to the space between both ends of the developing member in the rotational direction.

Description

Technical Field

[0001] The present disclosure relates to a developing device and an image forming system.

Background Art

[0002] Patent Document 1 discloses a developing device. This developing device includes a developing container, a developer carrier, a regulating portion, a facing portion, a sealing portion, and a sealing member. The developing container houses a developer containing toner and carrier. The developer carrier is a rotatable developer carrier that conveys the developer toward a developing position for developing an electrostatic image formed on an image carrier. This developer carrier has a carrying region and a non-carrying region. The carrying region is a region where the developer carrier has the ability to convey the developer. The non-carrying region is a region where the developer carrier does not have the ability to convey the developer. The regulating portion regulates the amount of developer carried on the carrying region. The facing portion is disposed to face the developer carrier downstream of the regulating portion and upstream of the developing position with respect to the rotational direction of the developer carrier. The sealing portion has flexibility and is provided to face the carrying region and the non-carrying region so as to contact the developer carried on the carrying region. The sealing member is provided on the sealing portion so as to be sandwiched between the sealing portion and the non-carrying region.

[0003] Patent Document 2 discloses a developing apparatus. This developing apparatus comprises a developer carrier, a developer supply member, a casing, and an agitator. The developer carrier transports the developer to the image carrier. The developer supply member supplies the developer to the developer carrier. The casing houses the developer. The agitator supplies the developer to the developer supply member while agitating the developer in the casing by rotation. The developer carrier also comprises a first electrode and a second electrode provided to the first electrode via an insulator. In this developing apparatus, the developer on the developer carrier is cloudified by applying a voltage that reverses the potential difference between the first electrode and the second electrode over time. The developer is then transported to the developing area by the movement of the surface of the developer carrier, and the electrostatic latent image formed on the image carrier is developed. The developer remaining on the developer carrier after development is allowed to enter the device through an opening between the developer carrier and an opening-forming member, which is provided to create a certain gap between the developer carrier and the device, and is then collected by the developer supply member. The developing device is also provided with a contact member that abuts against the developer supply member and closes the gap, so as to prevent the developer from leaking out of the device due to communication between the gap between the developer supply member and the casing and the aforementioned opening.

[0004] Patent Document 3 discloses a developing apparatus. This developing apparatus comprises a developing housing, a developer holder, a layer thickness regulating member, and a sealing member. The developing housing opens opposite an image holder that contains a developer and can hold an electrostatic latent image. The developer holder is provided facing the opening of the developing housing. This developer holder holds and transports the developer while rotating opposite the image holder. The layer thickness regulating member is provided for the upstream gap formed between the developer holder and the developing housing, located upstream of the opening in the rotational direction of the developer holder. This layer thickness regulating member regulates the layer thickness of the developer on the developer holder. The sealing member is provided for the downstream gap formed between the developer holder and the developing housing, located downstream of the opening in the rotational direction of the developer holder. This sealing member is made of a flexible plate material that extends in a long length along the rotational axis direction of the developer holder. Furthermore, the sealing member is fixed to the developing housing on its upstream side in the width direction along the rotational direction of the developer holder, and seals the downstream gap by contacting the developer on the developer holder on its downstream side in the width direction. In addition, the sealing member has multiple notches in the rotational axis direction of the developer holder, which are located at least 60% of the distance from the free end to the fixed end in the width direction from the free end and have an angle of 30° or less with respect to a reference line along the rotational direction of the developer holder. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2023-013157 [Patent Document 2] Japanese Patent Publication No. 2013-200379 [Patent Document 3] Japanese Patent Publication No. 2016-180829 [Overview of the project] [Problems that the invention aims to solve]

[0006] This disclosure aims to suppress the rise in internal pressure of the housing compared to a configuration in which the entire area of ​​the gap formed between the developing member and the housing is covered with a covering member. [Means for solving the problem]

[0007] A developing apparatus according to a first aspect of the present disclosure comprises a housing that houses a developer and has an opening opposite an image holder capable of holding a latent image; a developing member that is rotatably provided within the housing, exposed from the opening, and capable of holding the developer on its outer circumference, and developing the latent image with the held developer while rotating; and a covering member that covers the gap between the developing member and the housing downstream of the developing position in the rotational direction of the developing member, the covering member covering a first region in the gap corresponding to one end of the developing member in the rotational direction, and not covering at least a part of an intermediate region corresponding to the space between both ends of the developing member in the rotational direction.

[0008] A developing apparatus according to a second aspect of the present disclosure, in the developing apparatus according to the first aspect, wherein the covering member covers a second region in the gap that corresponds to the other end of the developing member in the direction of the rotation axis.

[0009] In a developing apparatus according to a third aspect of the present disclosure, the first region and the second region of the gap are respectively covered by a pair of covering members, in the developing apparatus according to the second aspect.

[0010] A developing apparatus according to a fourth aspect of the present disclosure, in which the developing apparatus according to the first aspect is supplied with the developing member from one end in the rotational axis direction of the developing member to the other end within the housing.

[0011] In the developing apparatus of the fifth aspect of this disclosure, in the developing apparatus of any one aspect of the first to fourth aspects, the area in the gap that is not covered by the covering member is 1 / 3 or more of the length of the holding area of ​​the developing member that holds the developer along the rotation axis direction.

[0012] A developing apparatus according to a sixth aspect of the present disclosure, in the developing apparatus according to the first aspect, wherein the covering member extends from the housing toward the developing member along the direction normal to the developing member.

[0013] A developing apparatus according to a seventh aspect of the present disclosure, in a developing apparatus according to a first aspect, wherein the covering member extends from the housing toward the developing member, with a base end fixed to the housing located toward the image holder side and a tip end located toward the rotation center side of the developing member.

[0014] An eighth aspect of the present disclosure is a developing apparatus according to the first aspect, further comprising: a sealing member extending tangentially to the developing member and sealing the end of the developing member in the direction of the rotation axis between the housing and the sealing member and the housing.

[0015] A developing apparatus according to a ninth aspect of the present disclosure is a developing apparatus according to a fourth aspect, wherein the housing is provided with a through hole for pressure relief in a portion corresponding to the other end of the developing member in the direction of the rotation axis.

[0016] An image forming system according to a tenth aspect of this disclosure comprises an image holder capable of holding a latent image, and a developing device according to a first aspect, disposed around the image holder and developing the latent image with a developer. [Effects of the Invention]

[0017] In the first embodiment of the developing apparatus, compared to a configuration in which the entire area of ​​the gap formed between the developing member and the housing is covered with a covering member, the rise in internal pressure of the housing can be suppressed.

[0018] In the second embodiment of the developing apparatus, compared to a configuration in which only the first region corresponding to one end of the developing member in the rotational axis direction in the gap is covered with a covering member, leakage of the developing agent can be suppressed.

[0019] In the developing apparatus of the third embodiment, compared to a configuration in which a single covering member covers the first and second regions of the gap, it becomes easier to adjust the position of the covering member with respect to the gap.

[0020] In the developing device according to the fourth aspect, compared with the configuration in which only the region corresponding to the other end portion in the rotation axis direction of the developing member is covered with the covering member in the gap, leakage of the developer can be suppressed.

[0021] In the developing device according to the fifth aspect, compared with the configuration in which the region not covered with the covering member in the gap is less than 1 / 3 of the length along the rotation axis direction of the holding region of the developing member, an increase in the internal pressure of the housing can be suppressed.

[0022] In the developing device according to the sixth aspect, compared with the configuration in which the covering member extends along the tangential direction of the developing member from the housing toward the developing member, the length from the base end portion to the tip end portion of the covering member can be shortened.

[0023] In the developing device according to the seventh aspect, compared with the configuration in which the base end portion of the covering member is located on the rotation center side of the developing member and the tip end portion is located on the image holding body side, turning up of the covering member due to an increase in the internal pressure of the housing can be suppressed.

[0024] In the developing device according to the eighth aspect, compared with the configuration in which the sealing member and the covering member are separately fixed to the housing, the fixing work of the sealing member and the covering member to the housing becomes easier.

[0025] In the developing device according to the ninth aspect, compared with the configuration in which a through hole for punching is provided in a portion of the housing corresponding to one end portion in the rotation axis direction of the developing member, leakage of the developer can be suppressed.

[0026] In the image forming device according to the tenth aspect, compared with the configuration in which a developing device that covers the entire region of the gap formed by the developing member and the housing with a covering member is used, an increase in the internal pressure of the housing of the developing device can be suppressed.

Brief Description of the Drawings

[0027] [Figure 1] It is a schematic diagram showing an image forming device according to the present embodiment. [Figure 2] It is a side sectional view of the developing device shown in FIG. 1. [Figure 3] It is a front view of the developing device shown in FIG. 2 as viewed from the opening side. [Figure 4] This is a cross-sectional view taken along line 4-4, as shown in Figure 3. [Figure 5] This is an enlarged view of the main parts of the developing apparatus according to this embodiment (a partial enlargement of Figure 2). [Figure 6] This is an enlarged view of the main parts of the developing apparatus according to this embodiment (a partial enlargement of Figure 4). [Figure 7] This is an enlarged view of the main parts of the developing apparatus according to this embodiment (enlarged view in the open area). [Figure 8] This is a front view of a developing apparatus according to another embodiment, as seen from the opening side. [Figure 9] This is a front view of a developing apparatus according to another embodiment, as seen from the opening side. [Figure 10] This is a cross-sectional view taken along line 10-10, as shown in Figure 9. [Modes for carrying out the invention]

[0028] An embodiment of this disclosure will be described below with reference to the drawings.

[0029] (Image forming apparatus 10) The configuration of an image forming apparatus 10 to which the image forming system according to this embodiment is applied will be described. Figure 1 is a schematic diagram showing the configuration of the image forming apparatus 10 according to this embodiment.

[0030] In the diagram, the arrow UP indicates the upper part of the device (specifically, vertically upward), and the arrow DO indicates the lower part of the device (specifically, vertically downward). The arrow LH indicates the left side of the device, and the arrow RH indicates the right side. The arrow FR indicates the front of the device, and the arrow RR indicates the rear of the device. These directions are defined for explanatory purposes only, and the device configuration is not limited to these directions. Note that the term "device" may be omitted in each direction of the device. For example, "upper part of the device" may simply be referred to as "upper."

[0031] Furthermore, in the following explanations, "up and down direction" may be used to mean "both upward and downward" or "either upward or downward." "Left and right direction" may be used to mean "both right and left" or "either right or left." Note that "left and right direction" can also be called lateral, sideways, and horizontal directions. "Front and back direction" may be used to mean "both forward and backward" or "either forward or backward." Note that "front and back direction" can also be called lateral, sideways, and horizontal directions. In addition, the up and down direction, left and right direction, and front and back direction are directions that intersect each other (specifically, orthogonal directions).

[0032] Furthermore, the symbol with a "×" inside a "○" in the diagram represents an arrow pointing from the front to the back of the page. Also, the symbol with a "·" inside a "○" in the diagram represents an arrow pointing from the back to the front of the page.

[0033] The image forming apparatus 10 shown in Figure 1 is an image forming apparatus. Specifically, as shown in Figure 1, the image forming apparatus 10 comprises a media storage unit 12, a transport unit 13, and an image forming unit 14. The parts of the image forming apparatus 10 will be described below.

[0034] (Media storage section 12) The media storage section 12 is the part of the image forming apparatus 10 that houses the recording medium P. The recording medium P housed in this media storage section 12 is supplied to the image forming section 14. The recording medium P housed in the media storage section 12 is the object on which an image is formed by the image forming section 14. Examples of recording medium P include paper and film. Examples of film include resin film and metal film. However, the recording medium P is not limited to those mentioned above, and various recording media can be used.

[0035] (Conveying section 13) The transport unit 13 shown in Figure 1 transports the recording medium P contained in the media storage unit 12 to the discharge unit (not shown). Specifically, as shown in Figure 2, the transport unit 13 has a plurality of transport members 13A such as transport rolls, and the recording medium P is transported by the transport members 13A. The transport members 13A may be, for example, transport belts and transport drums, and various transport members can be used.

[0036] (Image forming unit 14) The image forming unit 14 shown in Figure 1 forms an image on the recording medium P transported by the transport unit 13 (specifically, the transport member 13A). Specifically, the image forming unit 14 forms a toner image (an example of an image) on the recording medium P using an electrophotographic method. More specifically, as shown in Figure 1, the image forming unit 14 includes toner image forming units 20Y, 20M, 20C, and 20K (hereinafter referred to as 20Y to 20K), a transfer body 24, and a fixing unit 26.

[0037] Each of the toner image forming sections 20Y to 20K has a photoreceptor 32. Since the toner image forming sections 20Y to 20K are configured similarly, the reference numerals for the parts in the toner image forming sections 20Y, 20M, and 20C are omitted in Figure 1.

[0038] The photoreceptor 32 is an example of an image holder and is a structure that holds a latent image. Specifically, the photoreceptor 32 rotates in one direction (for example, counterclockwise in Figure 1). Around the photoreceptor 32, in order from the upstream side in the direction of rotation of the photoreceptor 32, are a charging device 34, an exposure device 36, and a developing device 38.

[0039] In each of the toner image forming sections 20Y to 20K, the charging device 34 charges the photoreceptor 32 (charging step). Furthermore, the exposure device 36 exposes the photoreceptor 32, which has been charged by the charging device 34, to form a latent image (specifically, an electrostatic latent image) on the photoreceptor 32 (exposure step). The photoreceptor 32 holds the latent image formed by the exposure device 36.

[0040] The developing device 38 then develops the latent image held by the photoreceptor 32 (developing process). This forms a toner image on the photoreceptor 32. The specific configuration of the developing device 38 will be described later.

[0041] In the image forming unit 14, each of the toner image forming units 20Y to 20K performs charging, exposure, and development processes to form toner images of yellow (Y), magenta (M), cyan (C), and black (K) on the transfer body 24. Furthermore, the image forming unit 14 transfers the toner images of each color formed on the transfer body 24 to the recording medium P, and fixes the toner images to the recording medium P in the fixing unit 26. In this way, the image forming unit 14 uses an intermediate transfer method in which the image is transferred to the recording medium P via the transfer body 24.

[0042] Furthermore, the image forming unit is not limited to the intermediate transfer method. For example, a direct transfer method that directly transfers the image to the recording medium P may be used, and various image forming units can be applied.

[0043] (Developing device 38) The developing apparatus 38 shown in Figures 2, 3, and 4 is, as described above, a device that develops the latent image held by the photoreceptor 32 using a developer. The developer is a developer containing toner and a magnetic carrier. Specifically, the developing apparatus 38 comprises a housing 60, a developing roll 80, and a cover film 90, as shown in Figure 2. The parts of the developing apparatus 38 will be described below.

[0044] (60 units) The housing 60 shown in Figures 2 and 4 has the function of housing the developer inside. When the developing device 38 is installed in each of the toner image forming sections 20Y to 20K, the housing 60 has an opening 64 that opens toward the photoreceptor 32 side (specifically, the left side), as shown in Figure 2. In other words, the housing 60 has an opening 64 that opens toward the photoreceptor 32 side.

[0045] As shown in Figures 2 and 3, a developing roll 80 for supplying developer to the photoreceptor 32 is provided inside the housing 60 so that a portion of it is exposed through the opening 64. A layer restricting member 84 is provided below the developing roll 80. In Figure 2, the photoreceptor 32 is shown by a dashed line when the developing device 38 is installed in the toner image forming section 20Y~20K.

[0046] Furthermore, the housing 60 includes a storage section 63 for storing developer supplied from a supply device (not shown). This storage section 63 includes a transport path for transporting the developer supplied from the supply device. In this embodiment, as an example, the transport path includes a supply path 61 and an agitation path 62.

[0047] The supply path 61 is positioned below the developing roll 80 and along the front-to-back direction. Specifically, the supply path 61 is positioned diagonally to the right and below the developing roll 80 and along the front-to-back direction. The developer supplied to the developing roll 80 is contained in this supply path 61. The developer in the supply path 61 is then transported in the transport direction (specifically, one direction in the front-to-back direction). Specifically, a transport auger 81, which acts as a transport member, is positioned in the supply path 61. The rotation of this transport auger 81 causes the developer in the transport direction (specifically, one direction in the front-to-back direction) in the supply path 61.

[0048] The agitation channel 62 is positioned adjacent to the supply channel 61 and along the supply channel 61. Specifically, the agitation channel 62 is positioned to the right of the supply channel 61 and along the front-to-back direction. The agitation channel 62 is connected to the front and rear ends of the supply channel 61 at their respective front and rear ends. The supply channel 61 and the agitation channel 62 form a circulation path.

[0049] The agitation channel 62 contains the developer sent from the supply device as the developer supplied to the supply channel 61. The delivered developer is transported in the opposite direction to the transport direction (specifically, the other direction in the front-to-back direction). Specifically, a transport auger 82 is positioned in the agitation channel 62 as a transport member. Due to the rotation of this transport auger 82, the developer is agitated in the agitation channel 62 and transported in the opposite direction to the transport direction (specifically, the other direction in the front-to-back direction).

[0050] (80 rolls of developing film) The developing roll 80 is rotatably mounted within the housing 60. The developing roll 80 is also exposed through the opening 64. The developing roll 80 is capable of holding developer on its outer circumference. The developing roll 80 has the function of developing the latent image formed on the photoreceptor 32 with the held developer while rotating. Specifically, the developing roll 80 is rotatably supported in the housing 60 with the front-to-back direction as the axis of rotation. The developing roll 80 holds developer on its outer circumference and transports the developer to the developing position D facing the photoreceptor 32. The developing position D here refers to the position where the developing roll 80 develops the latent image on the photoreceptor 32 using the developer.

[0051] The developer being transported toward the development position D has its layer thickness (amount of developer) restricted by the layer restricting member 84. Then, the developer (specifically toner) on the development roll 80 is supplied to the photoreceptor 32 at the development position D, and the latent image (electrostatic latent image) formed on the photoreceptor 32 is developed by the developer (specifically toner). The development roll 80 in this embodiment is an example of the developing member of this disclosure.

[0052] (Cover film 90) As shown in Figures 2, 3, and 4, the cover film 90 is a component that has the function of preventing developer leakage from the housing 60. This cover film 90 is an example of a covering component. As shown in Figure 2, the cover film 90 is positioned downstream of the development position D in the rotational direction of the development roll 80.

[0053] The cover film 90 is a component that covers the gap G between the developing roll 80 and the housing 60. Here, the gap G is the gap between the developing roll 80 and the housing 60 that is located downstream of the developing position D in the rotational direction of the developing roll 80. Specifically, as shown in Figures 2 and 4, the gap G is the gap formed between the ceiling portion 65 of the housing 60 and the developing roll 80. Also, as shown in Figure 3, the cover film 90 covers the gap G when viewed from the opening 64 side.

[0054] As shown in Figure 3, the cover film 90 covers a first region R1 in the gap G that corresponds to one end 80A of the developing roll 80 in the direction of rotation. The cover film 90 also covers a second region R2 in the gap G that corresponds to the other end 80B of the developing roll 80 in the direction of rotation. Specifically, the first region R1 and the second region R2 of the gap G are covered by the pair of cover films 90, respectively. In this embodiment, as an example, one end 80A of the developing roll 80 is located on the front side in the front-rear direction. That is, one end 80A of the developing roll 80 may be called the front end. However, this configuration is not limited to this, and one end 80A of the developing roll 80 may be located on the rear side in the front-rear direction. The other end 80B of the developing roll 80 in the direction of rotation is the end opposite to the one end 80A in the direction of rotation. Therefore, both ends of the developing roll 80 in the direction of rotation refer to one end 80A and the other end 80B of the developing roll 80.

[0055] The developing roll 80 is composed of one end 80A, the other end 80B, and an intermediate section 80C located between the two ends in the direction of rotation. The end of the developing roll 80 in the direction of rotation refers to the portion from the end face in the direction of rotation to, for example, 5% to 20% of the roll length. Here, the roll length is the length of the roll portion of the developing roll 80 along the direction of rotation. The intermediate section 80C of the developing roll 80 refers to the portion between the two ends in the direction of rotation.

[0056] As shown in Figure 3, the cover film 90 is positioned in the gap G such that it does not cover at least a portion of the intermediate region RM corresponding to the middle section 80C of the developing roll 80. Specifically, the gap G is composed of a first region R1, a second region R2, and an intermediate region RM. Here, for example, the first region R1 of the gap G is covered by one of the cover films 90. The second region R2 of the gap G is covered by the other cover film 90. The intermediate region RM of the gap G is not covered in the portion between the pair of cover films 90. That is, the portion of the intermediate region RM of the gap G between the pair of cover films 90 is open. The housing 60 can be depressurized through this open region.

[0057] Furthermore, in the gap G, the regions corresponding to each part in the rotation axis direction of the developing roll 80 refer to the regions in a direction perpendicular to the rotation axis direction of each part.

[0058] One cover film 90 may cover not only the first region R1 of the gap G but also a portion of the intermediate region RM adjacent to the first region R1. The other cover film 90 may cover not only the second region R2 of the gap G but also a portion of the intermediate region RM adjacent to the second region R2.

[0059] Developer is supplied to the developing roll 80 from one end 80A to the other end 80B within the housing 60. Specifically, the developing roll 80 is supplied with developer from the supply path 61. In this embodiment, as an example, the developer is transported from the front to the rear of the supply path 61. Therefore, the developing roll 80 is supplied with developer from the supply path 61 from one end 80A to the other end 80B.

[0060] As shown in Figure 3, in the gap G, an area is formed in the intermediate region RM that is not covered by the pair of cover films 90. This uncovered area refers to the open area of ​​the gap G (hereinafter simply referred to as the open region RO). Preferably, the open region RO is at least 1 / 3 of the length of the holding region HR that holds the developer of the developing roll 80 along the rotation axis direction. In this embodiment, the outer circumference of the roll portion of the developing roll 80 is composed of a holding region HR that holds the developer and a non-holding region NHR that does not hold the developer. The non-holding region NHR is formed at the ends of the roll portion in the direction of the rotation axis direction. The holding region HR is formed between the non-holding regions NHR on both sides of the roll portion in the direction of the rotation axis direction.

[0061] Furthermore, as shown in Figure 3, the end of the developing roll 80 in the direction of the rotation axis of this embodiment includes a non-retaining region NHR and a portion of the adjacent retaining region HR. Therefore, in the gap G, the non-retaining region NHR and a portion of the retaining region HR of the developing roll 80 are covered by the cover film 90.

[0062] The cover film 90 is fixed to a fixing part 66 provided on the ceiling portion 65 of the housing 60, which is located downstream of the development position D in the rotational direction of the developing roll 80. The fixing part 66 is inclined toward the developing roll 80. Specifically, the fixing part 66 is inclined diagonally downward to the right toward the developing roll 80. The base end portion 90A of the cover film 90 is fixed to this fixing part 66. The tip end portion 90B of the cover film 90 is a free end. The tip end portion 90B of the cover film 90 is positioned near the outer circumferential surface of the developing roll 80. Specifically, the tip end portion 90B of the cover film 90 is positioned so as to be in contact with the developer held by the developing roll 80. The tip end portion 90B of the cover film 90 may also be in contact with the outer circumferential surface of the developing roll 80. Furthermore, as a method of fixing the cover film 90 to the fixing part 66, for example, adhesive or fastening may be used. Examples of adhesive use include adhesive tape. Examples of fastening include adhesive tape. The method of fixing the cover film 90 to the fixing part 66 is not limited to the above.

[0063] The cover film 90 may extend from the housing 60 toward the developing roll 80 along the normal direction ND of the developing roll 80. Here, the statement that the cover film 90 extends along the normal direction ND includes, for example, cases where the cover film 90 is inclined at an angle of 10 degrees or less with respect to the normal direction ND. Specifically, as shown in Figure 5, the cover film 90 may extend such that the angle θ between the center line CL of the cover film 90 and the normal NL on the outer surface of the developing roll 80 is between 0 degrees and 10 degrees. Here, the center line CL of the cover film 90 is a straight line passing through the center of the cover film 90 in the thickness direction. The normal NL on the outer surface of the developing roll 80 is the normal at the intersection of the extension of the center line CL and the outer surface of the developing roll 80. The normal direction ND is the direction along the normal NL.

[0064] As shown in Figure 5, the cover film 90 has a base end 90A fixed to the housing 60 on the photoreceptor 32 side and a tip end 90B on the rotation center side of the developing roll 80.

[0065] The cover film 90 may, for example, be formed from a resin film. For example, polyethylene terephthalate (PET) may be used as the resin for forming the cover film 90.

[0066] Furthermore, the developing apparatus 38 may include side seals 100 extending along the tangential direction TD of the developing roll 80, as shown in Figures 3 and 4. In this embodiment, for example, the tangential direction TD refers to the direction along the tangential TL at the developing position D. The side seals 100 are an example of sealing members that seal the space between the end of the developing roll 80 in the direction of the rotation axis and the housing 60. Both ends of the developing roll 80 in the direction of the rotation axis are sealed by a pair of side seals 100. Note that the side seals 100 extending along the tangential direction TD includes, for example, cases where the side seals 100 are inclined at an angle of 10 degrees or less with respect to the tangential direction TD. Specifically, the upper end portion 100A of the side seals 100 is fixed to a wall portion 68 connecting the fixed portion 66 of the housing 60 and the opening 64. The side seals 100 extend from the wall portion 68 toward the developing roll 80. More specifically, the side seal 100 extends from the wall portion 68 toward the developing roll 80 so as to be in contact with the developing roll 80. In this embodiment, as an example, the side seal 100 extends linearly from the wall portion 68 toward the developing roll 80 and is in contact with the outer circumference of the developing roll 80. That is, as shown in Figure 6, the side seal 100 extends from the wall portion 68 along the tangential direction TD of the developing roll 80. Alternatively, the side seal 100 may extend curvedly from the wall portion 68 and be in contact with the outer circumference of the developing roll 80. The lower end portion 100B of the side seal 100 is fixed to the inner wall of the housing 60 located upstream of the developing position D.

[0067] In this embodiment, the side seal 100 is, for example, a film material. The same film material as the cover film 90 may be used.

[0068] Next, the operation of this embodiment will be described. In the developing apparatus 38 of this embodiment, in the gap G, the regions corresponding to both ends in the direction of the rotation axis of the developing roll 80 tend to leak developer more easily than the intermediate region RM because the developer circulates in the transport path. Therefore, in the developing apparatus 38 of this embodiment, the first region R1 of the gap G is covered with a cover film 90. In the developing apparatus 38, the cover film 90 suppresses the leakage of developer from the first region R1 of the gap G.

[0069] In the developing apparatus 38 of this embodiment, at least a portion of the intermediate region RM in the gap G is left uncovered, i.e., it is an open region RO. By providing this open region RO, even if the internal pressure of the housing 60 begins to rise due to the operation of the developing apparatus 38, fluid (gas) can escape from the open region RO (see Figure 7). Therefore, compared to a configuration in which the entire area of ​​the gap G is covered by the cover film 90, the developing apparatus 38 of this embodiment has an open region RO for pressure relief, which can suppress the rise in internal pressure of the housing 60.

[0070] In this embodiment, the developing apparatus 38 covers the second region R2 of the gap G with a cover film 90. Therefore, in the developing apparatus 38, the cover film 90 prevents the developer from leaking out of the second region R2 of the gap G. In other words, the developing apparatus 38 can suppress developer leakage compared to a configuration in which only the first region R1 is covered with the cover film 90.

[0071] In this embodiment, the developing apparatus 38 covers the first region R1 and the second region R2 of the gap G with a pair of cover films 90. Compared to a configuration in which a single cover film 90 covers both the first region R1 and the second region R2 of the gap G, this embodiment makes it easier to adjust the position of the cover film 90 relative to the gap G. Furthermore, it reduces the amount of material used for the cover film 90.

[0072] In the developing apparatus 38 of this embodiment, developer is supplied to the developing roll 80 from one end 80A in the rotational axis direction of the developing roll 80 to the other end 80B within the housing 60. Specifically, upstream of the developer supply direction, the charge of the developer is low, and the developer tends to easily become airborne as dust. Therefore, when the developer is supplied from one end 80A to the other end 80B within the housing 60, the first region R1 corresponding to the one end 80A is covered with the cover film 90 in the gap G. This suppresses developer leakage compared to a configuration in which only the second region R2 of the developing roll 80 is covered with the cover film 90 in the gap G.

[0073] In the developing apparatus 38 of this embodiment, the area in the gap G that is not covered by the cover film 90 is set to be at least 1 / 3 of the length of the holding area HR of the developing roll 80. Specifically, the open area RO in the gap G is set to be at least 1 / 3 of the length. Therefore, in the developing apparatus 38 of this embodiment, the rise in internal pressure of the housing 60 can be suppressed compared to a configuration in which the open area RO in the gap G is less than 1 / 3 of the length.

[0074] In the developing apparatus 38 of this embodiment, the cover film 90 extends from the housing 60 toward the developing roll 80 along the normal direction ND of the developing roll 80. Therefore, in the developing apparatus 38 of this embodiment, the length of the cover film 90 from the base end 90A to the tip end 90B can be shortened compared to a configuration in which the cover film 90 extends along the tangential direction of the developing roll 80.

[0075] In the developing apparatus 38 of this embodiment, the leading edge 90B of the cover film 90 is located downstream of the base edge 90A in the rotational direction of the developing roll 80. Therefore, compared to a configuration in which the leading edge 90B of the cover film 90 is located upstream of the base edge 90A in the rotational direction of the developing roll 80, the developing apparatus 38 can suppress the curling of the cover film 90 due to the rise in internal pressure of the housing 60.

[0076] (Other embodiments) In the above-described embodiment, the developer is supplied to the developing roll 80 from one end 80A to the other end 80B within the housing 60, but this disclosure is not limited to this configuration. The developer may be supplied to the developing roll 80 from the other end 80B to the one end 80A within the housing 60. Also, in the above-described embodiment, the cover film 90 covers the first region R1 and the second region R2 of the gap G, respectively, but this disclosure is not limited to this configuration. The cover film 90 may cover only the first region R1.

[0077] In the above-described embodiment, a pair of cover films 90 are fixed to the housing 60 so as to cover the first region R1 and the second region R2, but the present disclosure is not limited to this configuration. For example, an open region RO may be formed by cutting out a portion of a long cover film that corresponds to the intermediate region RM of the gap G. Alternatively, an open region RO may be formed by making multiple slits. Furthermore, an open region RO may be formed by providing one or more through holes in the portion of the cover film that corresponds to the intermediate region RM of the gap G.

[0078] Furthermore, in the embodiments described above, the intermediate region RM and the open region RO are the same size, but this disclosure is not limited to this configuration. For example, as shown in Figure 8, a portion of the intermediate region RM may be covered with the cover film 91.

[0079] In the embodiments described above, the cover film 90 and the side seal 100 are fixed to separate parts of the housing 60, but this disclosure is not limited to this configuration. For example, as shown in Figures 9 and 10, the cover film 90 and the side seal 100 may be fixed to the housing 60 via a fixing member 110. Specifically, the cover film 90 and the side seal 100 may be fixed to the fixing member 110, and this fixing member 110 may be fixed to the housing 60. With such a configuration, the work of fixing the side seal 100 and the cover film 90 to the housing 60 can be simplified compared to the configuration in which the cover film 90 and the side seal 100 are fixed to the housing 60 separately. The cover film 90 and the side seal 100 may be fixed to the fixing member 110 by adhesive or by fastening. Similarly, the fixing member 110 to the housing 60 may also be fixed by adhesive or by fastening.

[0080] In the above-described embodiment, the housing 60 is not provided with a through hole for pressure relief, but the present disclosure is not limited to this configuration. For example, the housing 60 may be provided with a through hole for pressure relief in the portion corresponding to the other end 80B of the developing roll 80. The rise in internal pressure inside the housing 60 tends to be suppressed around the portion where the through hole for pressure relief is provided. Therefore, if the housing 60 is provided with a through hole for pressure relief, it is preferable to provide the cover film 90 on the side opposite to the side where the through hole for pressure relief is provided. In this case, compared to a configuration in which the housing 60 is provided with a through hole for pressure relief in the portion corresponding to one end 80A of the developing roll 80, leakage of developer from the gap G can be suppressed.

[0081] This disclosure is not limited to the embodiments described above, and various modifications, changes, and improvements are possible without departing from its spirit. For example, the modifications shown above may be combined in any way.

[0082] (Note) (((1))) A housing that contains a developer and has an opening facing an image holder capable of retaining a latent image, A developing member is rotatably provided within the housing, exposed from the opening, capable of holding the developer on its outer circumference, and develops the latent image with the held developer while rotating; A covering member that covers the gap between the developing member and the housing downstream of the developing position in the rotational direction of the developing member, wherein the covering member covers a first region corresponding to one end of the developing member in the rotational direction and does not cover at least a part of the intermediate region corresponding to the space between both ends of the developing member in the rotational direction, A developing apparatus equipped with a developing device. (((2))) The developing apparatus according to (((1))), wherein the covering member covers a second region in the gap that corresponds to the other end of the developing member in the direction of the rotation axis. (((3))) The developing apparatus according to (((2))), wherein the first region and the second region of the gap are each covered by a pair of covering members. (((4))) The developing apparatus according to (((1))), wherein the developing agent is supplied to the developing member from one end in the rotational axis direction of the developing member to the other end within the housing. (((5))) In the gap, the area not covered by the covering member is at least 1 / 3 of the length of the holding area of ​​the developing member that holds the developer along the rotation axis, according to any one of (((1))) to (((4))). (((6))) The developing apparatus according to any one of (((1))) to (((5))), wherein the covering member extends from the housing toward the developing member along the direction normal to the developing member. (((7))) The developing apparatus according to any one of (((1))) to (((6))), wherein the covering member extends from the housing toward the developing member, with its base end fixed to the housing positioned toward the image holder and its tip positioned toward the rotation center of the developing member. (((8))) A sealing member extending in the tangential direction of the developing member and sealing the end of the developing member in the direction of the rotation axis with the housing, A fixing member for fixing the sealing member and the covering member to the housing, A developing apparatus according to any one of items (((1))) to (((7))) further comprising: (((9))) The developing apparatus according to (((4))), wherein the housing is provided with a through hole for pressure relief in a portion corresponding to the other end of the developing member in the direction of the rotation axis. (((10))) An image holder capable of retaining a latent image, An image forming system comprising: a developing device according to any one of (((1))) to (((9)))) arranged around the image holder and developing the latent image with a developer.

[0083] In the developing apparatus of (((1))), the rise in internal pressure of the housing can be suppressed compared to a configuration in which the entire area of ​​the gap formed between the developing member and the housing is covered with a covering member. In the developing apparatus of (((2))), compared to a configuration in which only the first region corresponding to one end of the developing member in the rotational axis direction is covered by the covering member in the gap, leakage of the developing agent can be suppressed. In the developing apparatus of (((3))), compared to a configuration in which a single covering member covers the first and second regions of the gap, it becomes easier to adjust the position of the covering member relative to the gap. In the developing apparatus of (((4))), compared to a configuration in which only the region corresponding to the other end of the developing member in the direction of the rotation axis in the gap is covered with a covering member, leakage of the developing agent can be suppressed. In the developing apparatus of (((5))), the increase in internal pressure of the housing can be suppressed compared to a configuration in which the area not covered by the covering member in the gap is less than 1 / 3 of the length along the rotation axis direction of the holding area of ​​the developing member. In the developing apparatus of (((6))), the length of the covering member from the base end to the tip can be shortened compared to a configuration in which the covering member extends from the housing toward the developing member along the tangential direction of the developing member. In the developing apparatus of (((7))), compared to a configuration in which the leading edge of the covering member is located upstream of the base end in the rotational direction of the developing member, it is possible to suppress the peeling of the covering member due to the rise in internal pressure of the housing. In the developing apparatus of (((8))), the process of fixing the sealing member and the covering member to the housing is simplified compared to a configuration in which the sealing member and the covering member are fixed separately to the housing. In the developing apparatus of (((9))), compared to a configuration in which a through hole for pressure relief is provided in the housing at a portion corresponding to one end of the developing member in the rotational axis direction, leakage of the developing agent can be suppressed. In the image forming system (((10))), compared to a configuration using a developing device in which the entire area of ​​the gap formed between the developing element and the housing is covered with a covering element, the rise in internal pressure of the housing of the developing device can be suppressed. [Explanation of Symbols]

[0084] 10 Image forming apparatus 12 Media storage section 13 Conveying section 13A Conveying Member 14 Image forming unit 20 Toner image forming unit 24 Transfer material 26 Fixing section 32 Photoreceptor 34 Charging device 36 Exposure apparatus 38 Developing device 60 cabinets 61 Supply route 62 Stirring path 63 Storage Unit 64 openings 65 Ceiling section 66 Fixed part 68 Wall 80 developing rolls 80A one end 80B Other end 80C middle part 81 Conveyor Auger 82 Conveyor Auger 84-layer restricting member 90 Cover film 90A proximal end 90B Tip 91 Cover film 100 Side Seals 100A Upper end 100B lower end 110 Fixed parts θ angle CL centerline D. Phenomenon Location G gap HR maintains its position ND normal direction NHR Non-holding area NL normal P Recording Media R1 First Domain R2 Second Domain RM Intermediate Field RO Open Domain TD wiring direction

Claims

1. A housing that contains a developer and has an opening facing an image holder capable of retaining a latent image, A developing member is rotatably provided within the housing, exposed from the opening, capable of holding the developer on its outer circumference, and develops the latent image with the held developer while rotating; A covering member that covers the gap between the developing member and the housing downstream of the developing position in the rotational direction of the developing member, wherein the covering member covers a first region corresponding to one end of the developing member in the rotational direction and does not cover at least a part of the intermediate region corresponding to the space between both ends of the developing member in the rotational direction, A developing apparatus equipped with a developing device.

2. The developing apparatus according to claim 1, wherein the covering member covers a second region in the gap that corresponds to the other end of the developing member in the direction of the rotation axis.

3. The developing apparatus according to claim 2, wherein the first region and the second region of the gap are each covered by a pair of covering members.

4. The developing apparatus according to claim 1, wherein the developing agent is supplied to the developing member from one end in the rotational axis direction of the developing member to the other end within the housing.

5. The developing apparatus according to any one of claims 1 to 4, wherein the area in the gap that is not covered by the covering member is 1 / 3 or more of the length of the holding area of ​​the developing member that holds the developer along the rotation axis direction.

6. The developing apparatus according to claim 1, wherein the covering member extends from the housing toward the developing member along the direction normal to the developing member.

7. The developing apparatus according to claim 1, wherein the covering member extends from the housing toward the developing member, with its base end fixed to the housing positioned toward the image holder side and its tip end positioned toward the rotation center side of the developing member.

8. A sealing member extending in the tangential direction of the developing member and sealing the end of the developing member in the direction of the rotation axis with the housing, A fixing member for fixing the sealing member and the covering member to the housing, The developing apparatus according to claim 1, further comprising:

9. The developing apparatus according to claim 4, wherein the housing is provided with a through hole for pressure relief in a portion corresponding to the other end of the developing member in the direction of the rotation axis.

10. An image holder capable of retaining a latent image, A developing apparatus according to claim 1, which is arranged around the image holder and develops the latent image with a developer, An image forming system comprising the following features.

Images