Source: http://www.patentsencyclopedia.com/app/20110158709
Timestamp: 2018-04-25 05:26:55
Document Index: 260414639

Matched Legal Cases: ['art 89', 'art 89', 'art 89', 'art 46', 'art 109', 'art 109', 'art 109', 'art 109', 'art 105', 'art 105', 'art 105', 'art 101', 'art 101', 'arts 50', 'art 105', 'art 106', 'art 114', 'art 115', 'art 105', 'art 114', 'art 106', 'art 115', 'art 105', 'art 114', 'art 106', 'art 115', 'art 106', 'art 115', 'art 106', 'art 115', 'art 105', 'art 114', 'art 105', 'art 105', 'art 105', 'art 105', 'art 105', 'art 88', 'art 105', 'art 88', 'art 106', 'art 115', 'art 106', 'art 115', 'arts 65', 'arts 65', 'arts 50', 'art 106', 'art 115', 'art 105', 'art 114', 'art 105', 'art 105', 'art 104', 'art 104', 'art 104', 'art 104', 'art 104', 'art 104', 'art 104']

Inventors: Hiroki Mori (Nagoya-Shi, JP)
Patent application number: 20110158709
A developing device and an image forming apparatus including the developing device are provided. The developing device includes a housing, a developer carrier which is rotatably supported by the housing, and which carries developer on a circumferential surface thereof, a layer thickness regulating member which includes, a blade contacting the circumferential surface of the developer carrier along a rotational axial direction of the developer carrier, and a support member supporting the blade, the layer thickness regulating member for regulating a layer thickness of the developer on the circumferential surface of the developer carrier. The support member includes: a contact part which contacts the blade; and a pair of attachment parts which are attached to the housing. The attachment parts are provide at both sides of the contact part in the rotational axial direction and are further protruded than the contact part in a direction away from the developer carrier.
1. A developing device comprising: a housing; a developer carrier which is rotatably supported by the housing, and which is configured to carry developer on a circumferential surface thereof; and a layer thickness regulating member which includes: a blade configured to contact the circumferential surface of the developer carrier along a rotational axial direction of the developer carrier; and a support member supporting the blade, the layer thickness regulating member being configured to regulate a layer thickness of the developer on the circumferential surface of the developer carrier, wherein the support member includes: a contact part which contacts the blade; and a pair of attachment parts which are attached to the housing, and wherein the attachment parts are provide at both sides of the contact part in the rotational axial direction and are further protruded than the contact part in a direction away from the developer carrier.
2. The developing device according to claim 1, wherein the attachment parts are provided at both end portions of the contact part in the rotational axial direction.
3. The developing device according to claim 1, wherein the layer thickness regulating member further includes: a reinforcement member which is provided at an opposite side to the support member with respect to the blade and which reinforces the blade, wherein the support member and the reinforcement member are bent at bending portions, respectively, as viewed from the rotational axial direction, wherein the support member includes a first support part provided at one side with respect to the bending portion and a second support part provided at the other side with respect to the bending portion, wherein the reinforcement member includes a first reinforcement part provided at one side with respect to the bending portion and a second reinforcement part provided at the other side with respect to the bending portion, and wherein the first support part and the first reinforcement part sandwich the blade therebetween, and the second support part and the second reinforcement part are fixed with each other.
4. The developing device according to claim 3, wherein the first support part is provided at an opposite side to the developing carrier with respect to the blade, wherein both end portions of the first support part in the rotational axial direction are provided with protrusions, respectively, which are provided on a same plane as the first support part and protruded in the direction away from the developer carrier, and wherein the attachment parts are provided at the protrusions, respectively.
5. The developing device according to claim 3, wherein in the layer thickness regulating member, only the attachment parts are attached to the housing.
6. The developing device according to claim 3, wherein the housing is formed with a recess part which is recessed along a U-shape defined by the first support part and the pair of attachment parts.
7. The developing device according to claim 3, wherein the second support part and the second reinforcement part are fixed by a screw, wherein the housing is formed with a receiving hole which is configured to receive the screw with allowance in an attachment direction of the attachment parts to the housing, wherein a part of the housing corresponding to a deepest part of the receiving hole is extended up to an opposing surface of the housing, which opposes the blade, and wherein a seal member is provided between the blade, and the opposing surface and the part of the housing.
8. The developing device according to claim 1, wherein a surface of the housing, which opposes the layer thickness regulating member is formed with a recess at a part opposing an edge portion of each of the attachment parts.
9. The developing device according to claim 1, wherein the blade is fixed to the contact part of the support member by welding.
10. An image forming apparatus comprising: a developing device including: a housing; a developer carrier which is rotatably supported by the housing, and which is configured to carry developer on a circumferential surface thereof; and a layer thickness regulating member which includes: a blade configured to contact the circumferential surface of the developer carrier along a rotational axial direction of the developer carrier; and a support member supporting the blade, the layer thickness regulating member being configured to regulate a layer thickness of the developer on the circumferential surface of the developer carrier, wherein the support member includes: a contact part which contacts the blade; and a pair of attachment parts which are attached to the housing, and wherein the attachment parts are provide at both sides of the contact part in the rotational axial direction and are further protruded than the contact part in a direction away from the developer carrier; a photosensitive body including a circumferential surface, on which an electrostatic latent image is formed; and an exposure unit which is configured to irradiate the circumferential surface of the photosensitive body with light to expose it, thereby forming an electrostatic latent image on the circumferential surface of the photosensitive body, wherein a light path from the exposure unit to the photosensitive body passes between the pair of attachment parts.
11. A developing device comprising: a housing including a ceiling wall, a bottom wall, a back side wall, and a pair of sidewalls; a developing roller which is rotatably supported by the pair of sidewalls at both end portions in a rotational axial direction, and which is configured to carry developer on a circumferential surface thereof; a layer thickness regulating member which is configured to regulate a layer thickness of the developer on the circumferential surface of the developing roller, wherein the ceiling wall includes: a first ceiling wall which is provided between the sidewalls and at a side of the bottom wall with respect to an upper end of the sidewalls as viewed from the rotational axial direction; and a second ceiling wall which is provided on the upper end of the sidewalls and an upper end of the back side wall, wherein the layer thickness regulating member is provided on the first ceiling wall from a side opposite to the developing roller with respect to the ceiling wall.
12. The developing device according to claim 11, wherein the layer thickness regulating member includes: a blade which is configured to contact the circumferential surface of the developing roller along the rotational axial direction; a support member which supports the blade; and a reinforcement member which is provided at an opposite side to the support member with respect to the blade and which reinforces the blade, wherein the support member and the reinforcement member are both bent at bending portions, respectively, as viewed from the rotational axial direction, wherein the support member includes a first support part provided at one side with respect to the bending portion and a second support part provided at the other side with respect to the bending portion, wherein the reinforcement member includes a first reinforcement part provided at one side with respect to the bending portion and a second reinforcement part provided at the other side with respect to the bending portion, and wherein the first support part and the first reinforcement part sandwich the blade therebetween, and the second support part and the second reinforcement part are fixed with each other and provided on the first ceiling wall.
[0001] This application claims priority from Japanese Patent Application Nos. 2009-294596, filed on Dec. 25, 2009, and 2010-053661, filed on Mar. 10, 2010, the entire subject matter of which is incorporated herein by reference.
[0002] Aspects of the present invention relate to a developing device that is detachably mounted on an image forming apparatus such as a laser printer, and an image forming apparatus including the developing device.
[0003] As a developing device, there is known a developing cartridge that is detachably mounted on an image forming apparatus and is configured to develop an electrostatic latent image on a photosensitive drum (for example, refer to JP-A-2008-51875)
[0004] The developing cartridge described in JP-A-2008-51875 includes a housing which accommodates toner and rotatably supports a developing roller configured to carry the accommodated toner on a circumferential surface thereof. In forming an image, the developing roller contacts a photosensitive drum over an entire area thereof in a rotational axial direction of the developing roller and is rotated to supply toner to an electrostatic latent image formed on the photosensitive drum. Accordingly, it is possible to develop the electrostatic latent image on the photosensitive drum.
[0005] Herein, the developing cartridge is provided with a layer thickness regulating blade which is configured to regulate a thickness (layer thickness) of the toner on the circumferential surface of the developing roller.
[0006] Recently, there is a need to reduce the size of the developing cartridge. However, according to the related-art structure of the developing cartridge, a space for providing the layer thickness regulating blade is required, so that it has been not possible to satisfy the need to reduce the size of the developing cartridge.
[0007] Accordingly, an aspect of the present invention is to provide a developing device which can be size-reduced and an image forming apparatus including the developing device.
[0008] According to an illustrative embodiment of the present invention, there is provided a developing device comprising: a housing; a developer carrier which is rotatably supported by the housing, and which is configured to carry developer on a circumferential surface thereof; and a layer thickness regulating member which includes: a blade configured to contact the circumferential surface of the developer carrier along a rotational axial direction of the developer carrier; and a support member supporting the blade, the layer thickness regulating member being configured to regulate a layer thickness of the developer on the circumferential surface of the developer carrier. The support member includes: a contact part which contacts the blade; and a pair of attachment parts which are attached to the housing. The attachment parts are provide at both sides of the contact part in the rotational axial direction and are further protruded than the contact part in a direction away from the developer carrier.
[0009] According to another illustrative embodiment of the present invention, there is provided an image forming apparatus comprising: the above developing device; a photosensitive body including a circumferential surface, on which an electrostatic latent image is formed; and an exposure unit which is configured to irradiate the circumferential surface of the photosensitive body with light to expose it, thereby forming an electrostatic latent image on the circumferential surface of the photosensitive body. A light path from the exposure unit to the photosensitive body passes between the pair of attachment parts.
[0010] According to a further illustrative embodiment of the present invention, there is provided a developing device comprising: a housing including a ceiling wall, a bottom wall, a back side wall, and a pair of sidewalls; a developing roller which is rotatably supported by the pair of sidewalls at both end portions in a rotational axial direction, and which is configured to carry developer on a circumferential surface thereof; a layer thickness regulating member which is configured to regulate a layer thickness of the developer on the circumferential surface of the developing roller. The ceiling wall includes: a first ceiling wall which is provided between the sidewalls and at a side of the bottom wall with respect to an upper end of the sidewalls as viewed from the rotational axial direction; and a second ceiling wall which is provided on the upper end of the sidewalls and an upper end of the back side wall. The layer thickness regulating member is provided on the first ceiling wall from a side opposite to the developing roller with respect to the ceiling wall.
[0012] FIG. 1 is a right side sectional view of a printer according to an illustrative embodiment of the present invention;
[0013] FIG. 2 is a right side sectional view of a process cartridge;
[0014] FIG. 3 is a right side sectional view of a developing cartridge;
[0015] FIG. 4 is a perspective view of the developing cartridge, which is seen from a front-left upper direction;
[0016] FIG. 5 is an exploded perspective view of a developing frame;
[0017] FIG. 6 is a perspective view of the completed developing frame, which is seen from a front-right upper direction;
[0018] FIG. 7A is a right side view of the developing cartridge;
[0019] FIG. 7B is a right side sectional view of the developing cartridge;
[0020] FIG. 8 is a perspective view of a layer thickness regulating member, which is seen from a front-left upper direction;
[0021] FIG. 9 is an exploded perspective view of the layer thickness regulating member;
[0022] FIG. 10 is a right side sectional view of the layer thickness regulating member and a developing roller;
[0023] FIG. 11 is a right side sectional view of the layer thickness regulating member and the developing roller according to a modified illustrative embodiment; and
[0024] FIG. 12 is a perspective view of a developing cartridge including a layer thickness regulating member according to a modified illustrative embodiment, which is seen from a front-left upper direction.
[0025] As shown in FIG. 1, a printer 1 (an example of an image forming apparatus) includes, in a body casing 2, a feeder unit 3 configured to feed a sheet S (an example of a recording medium), and an image forming unit 4 configured to form an image on the fed sheet S.
[0026] The body casing 2 has a substantially rectangular box shape, when seen from a side face, and houses the feeder unit 3 and the image forming unit 4. The body casing 2 has a cover 5 at one side wall thereof for mounting and removing a process cartridge 13 (described later). The cover 5 is provided to the body casing 2 so as to be rotatable about a lower end portion as a support point. When the cover 5 is opened, the process cartridge 13 can be mounted on or removed the body casing 2.
[0027] In the below descriptions, a side (right side in FIG. 1) to which the cover 5 is provided is referred to as the back side and an opposite side (left side in FIG. 1) is referred to as the front side. In addition, the left and the right are defined when seen from the front side of the printer 1. In other words, the back side of the drawing sheet of FIG. 1 is the left side and the front side of the drawing sheet of FIG. 1 is the right side. Further, a left-right direction may be referred to as a width direction.
[0028] The feeder unit 3 is provided at a lower part of the body casing 2. The feeder unit 3 includes a sheet feeding tray 6 that receives sheets S, a pickup roller 7 that is provided above a rear end portion of the sheet feeding tray 6 and a separation roller 8 and a separation pad 9, which are opposed to each other at a back side of the pickup roller 7. In addition, the feeder unit 3 has a pair of front and rear feeder rollers 10, which are opposed to each other above the separation pad 9, a sheet feeding path 11 that extends from an opposing area between both the feeder rollers 10 in a substantially front-upper direction and a main body-side registration roller 20 that is provided at the front side of the sheet feeding path 11.
[0029] The sheets S are stacked in the sheet feeding tray 6. The uppermost sheet S is fed to an opposing area between the separation roller 8 and the separation pad 9 by rotation of the pickup roller 7, as indicated by the dotted line. The sheets S are separated one-by-one by the separation roller 8 and the separation pad 9. Then, the sheet S passing through the sheet feeding path 11 by the feeder rollers 10 is conveyed between the main body-side registration roller 20 and a process-side registration roller 21 (described later) and is further conveyed toward between a photosensitive drum 17 (described later; an example of a photosensitive member) and a transfer roller 19 (described later).
[0030] In the meantime, separately from the feeder unit 3, there is provided a sheet reverse mechanism that returns the sheet S from a sheet discharge path 27 (described later) toward between the main body-side registration roller 20 and the process-side registration roller 21 (described later) as indicated by the dotted line, so that a two-sided printing can be made with the printer 1.
[0031] The image forming unit 4 includes an exposure unit 12, a process cartridge 13 and a fixing unit 14.
[0032] The exposure unit 12 is provided at the upper part of the body casing 2. The exposure unit 12 emits light (laser beam indicated by the dotted arrow) toward the photosensitive drum 17 (described later), based on image data, thereby exposing the photosensitive drum 17 (described later).
[0033] The process cartridge 13 is detachably received at the lower part of the exposure unit 12 and at the upper part of the feeder unit 3 in the body casing 2. The process cartridge 13 includes a drum cartridge 15 and a developing cartridge 16 (an example of a developing device) detachably attached to the drum cartridge 15.
[0034] The drum cartridge 15 includes the photosensitive drum 17, a scorotron-type charger 18 and the transfer roller 19.
[0035] The photosensitive drum 17 is long in the width direction and is rotatably provided at a front end portion of the drum cartridge 15 along the left-right direction. The charger 18 is provided to oppose the photosensitive drum 17 at an interval therebetween at the front-upper side of the photosensitive drum 17. The transfer roller 19 is provided to oppose the lower side of the photosensitive drum 17 and is press-contacted to the lower side of the photosensitive drum 17.
[0036] In addition, the drum cartridge 15 includes the process-side registration roller 21.
[0037] The process-side registration roller 21 is provided to contact the upper side of the main body-side registration roller 20 at a lower part of a substantially center portion in the front-rear direction of the drum cartridge 15.
[0042] A thickness (layer thickness) of toner supplied on the developing roller 22 is regulated by the layer thickness regulating member 24 as the developing roller 22 is rotated, and the toner is carried on the surface (circumferential surface) of the developing roller 22 as a thin layer having a predetermined thickness.
[0099] Herein, a right end surface of the coupling gear 83 is formed with a coupling part 89 that is recessed leftward and the coupling part 89 is typically exposed rightward from the cover 87 (refer to FIG. 4). Specifically, the coupling part 89 includes a cylindrical wall which stands rightward and two projecting parts which project from the cylindrical wall in a radial direction thereof. In addition, the body casing 2 (refer to FIG. 2) is provided with a coupling member (not shown; an example of a driving-side coupling member) connected to a driving source (not shown: for example, motor).
[0104] In FIG. 7B, as viewed from the width direction, the coupling gear 83 indicated by the dotted line is overlapped with the connection part X between the first frame 46 and the second frame 47 (strictly, the inclined surface 60 of the first frame 46 and the inclined surface 63 of the second frame 47). Specifically, as viewed from the width direction, a rotation center 83A of the coupling gear 83 is overlapped with at least one of the first frame 46 and the second frame 47 (herein, a thick part 46A of the first frame 46 in the inclined surface 60) in the connection part X.
[0124] Herein, since the left penetration hole 103L is a long hole, the left convex part 109L, is certainly inserted into the left penetration hole 103L even when there is an error in the distance between the convex part 109R and the convex part 109L. In addition, the front end portion of each convex part 109 inserted into the corresponding penetration holes 103 is protruded forward from the front side face of the blade 100 in the thickness direction (front-rear direction) of the blade 100.
[0165] (1) Referring to FIG. 3, in the developing cartridge 16, the developing roller 22 configured to carry toner on the circumferential surface is rotatably supported by the developing frame 40. In addition, the developing cartridge 16 includes the layer thickness regulating member 24.
[0166] The layer thickness regulating member 24 includes the blade 100 configured to contact the circumferential surface of the developing roller 22 over the entire area of the rotational axial direction (width direction) of the developing roller 22 and thus regulates a layer thickness of toner on the circumferential surface of the developing roller 22, and the support member 101 that supports the blade 100.
[0167] The support member 101 includes the first support part 105 which contacts the blade 100 and the protrusions 108 which are attached to the developing frame 40. The protrusions 108 are positioned at both widthwise end portions of the first support part 105 and are further protruded than the first support part 105 in a direction (upper direction) away from the developing roller 22 (refer to FIG. 9).
[0168] In other words, in the support member 101 of the layer thickness regulating member 24, the parts that are further protruded than the first support part 101 in a direction away from the developing roller 22 are only the protrusions 108 at both widthwise end portions of the first support part 101. Accordingly, compared to a case where a portion between the protrusions 108 at both end portions is also protruded, it is possible to reduce the size of the developing cartridge 16.
[0169] In addition, the layer thickness regulating member 24 is attached to the developing frame 40 only at the left and right protrusions 108, so that it is possible to reduce the attachment space of the layer thickness regulating member 24 in the developing frame 40 into only the left and right screw parts 50. Therefore, it is possible to reduce the entire size of the developing cartridge 16. In addition, the light path L of the laser beam passes between the left and right protrusions 108, so that it is possible to approach the light path L to the developing cartridge 16 (layer thickness regulating member 24) as close as possible. Therefore, it is possible to reduce the entire size of the printer 1, by the approached dimension (refer to FIG. 1).
[0170] As shown in FIG. 8, only the left and right protrusions 108 of the support member 101 of the layer thickness regulating member 24 are upwardly protruded. Thereby, in a case where the developing cartridge 16 shown in FIG. 4 is dropped to the ground or the developing cartridge 16 is attached and detached to and from the body casing 2 (refer to FIG. 1), even when an outside object collides with the layer thickness regulating member 24, the shock is received by the left and right protrusions 108 and does not act on the blade 100. Therefore, it is possible to prevent the blade 100 from being damaged.
[0171] In other words, it is possible to prevent the blade 100 from being damaged while securing the light path L (refer to FIG. 1) and the attachment space of the layer thickness regulating member 24 to the developing frame 40.
[0172] (2) Referring to FIG. 10, the layer thickness regulating member 24 has the reinforcement member 102 that is provided at an opposite side to the support member 101 with respect to the blade 100 and reinforces the blade 100.
[0173] Herein, both the support member 101 and the reinforcement member 102 are bent, as viewed from the width direction. Accordingly, it is possible to increase the rigidity of each of the support member 101 and the reinforcement member 102 and to reduce the height of the support member 101 and the reinforcement member 102 (in other words, the entire height of the layer thickness regulating member 24) to be small.
[0174] In the support member 101, one side with respect to the bending portion 101A configures the first support part 105 and the other side with respect to the bending portion 101A configures the second support part 106. Additionally, in the reinforcement member 102, one side with respect to the bending portion 102A configures the first reinforcement part 114 and the other side with respect to the bending portion 102A configures the second reinforcement part 115.
[0175] The first support part 105 and the first reinforcement part 114 sandwich the blade 100 therebetween while opposing each other, and the second support part 106 and the second reinforcement part 115 are fixed while opposing each other. Thereby, the blade 100 sandwiched by the first support part 105 and the first reinforcement part 114 is provided at an opposite side to the fixed part of the second support part 106 and the second reinforcement part 115 (fixed part of the support member 101 and the reinforcement member 102) with respect to the bending portions 101A, 102A of the support member 101 and the reinforcement member 102. Therefore, it is possible to separate the blade 100 from the fixed part.
[0176] Accordingly, when fixing the second support part 106 and the second reinforcement part 115 by the screws 118, as in the above-described illustrative embodiment, it is possible to prevent the problem that the force, by which the screws 118 fix the second support part 106 and the second reinforcement part 115 at the fixed part acts on the blade 100 and thus the blade 100 is unnecessarily bent (waved).
[0177] (3) The first support part 105, which sandwiches the blade 100 together with the first reinforcement part 114 (i.e., contacts the blade 100 and thus supports the blade 100), is provide at the opposite side to the developing roller 22 with respect to the blade 100. Therefore, the force, by which the developing roller 22 presses the blade 100 at the front side can be supported by the first support part 105 from the downstream side (back side) of the force acting direction. Thus, it is possible to prevent the position of the blade 100 from being dislocated by the force. Thereby, it is possible to improve the positioning precision of the blade 100 with respect to the circumferential surface of the developing roller 22.
[0178] Additionally, both widthwise end portions of the first support part 105 are provided with the protrusions 108 that are provide on the same plane Y as the first support part 105 and are further protruded than the reinforcement member 102 in a direction away from the developing roller 22 (refer to FIG. 9). In other words, the protrusions 108 attached to the developing frame 40 (refer to FIG. 4) and the first support part 105 supporting the blade 100 are provide on the same plane Y. Therefore, when the protrusions 108 are attached to the developing frame 40 with high precision, it is possible to provide the first support part 105 (blade 100) at a desired position with high precision also. As a result, it is possible to further improve the positioning precision of the blade 100 to the circumferential surface of the developing roller 22.
[0179] (4) As shown in FIG. 4, in the layer thickness regulating member 24, only the protrusions 108 of the support member 101 are attached to the developing frame 40. Therefore, compared to a case where the other parts (for example, reinforcement member 102 and the like) of the layer thickness regulating member 24 except the protrusions 108 are also attached to the developing frame 40, it is possible to attach the entire layer thickness regulating member 24 to the developing frame 40 with high precision just by attaching the protrusions 108 to the developing frame 40 with high precision (in other words, it is possible to position the blade 100 with respect to the circumferential surface of the developing roller 22 with high precision).
[0180] (5) The developing frame 40 is formed with the recess part 88 that is recessed along the U-shaped pattern defined by the first support part 105 (refer to FIG. 9) and the protrusions 108. Accordingly, it is possible to reduce the size of the developing cartridge 16, correspondingly to the recess part 88.
[0181] (6) The second support part 106 and the second reinforcement part 115 are assembled by the screws 118 (refer to FIG. 10). Correspondingly to this, the developing frame 40 is formed with the receiving holes 64 that receive the screws 118, as shown in FIG. 6.
[0182] Herein, the receiving holes 64 can receive the screws 118 (refer to FIG. 10) with allowance in the attachment direction (front-rear direction) of the protrusions 108 (in other words, the entire layer thickness regulating member 24) to the developing frame 40. Therefore, in attaching the layer thickness regulating member 24 (refer to FIG. 8) to the developing frame 40, it is possible to prevent the screws 118 from being caught in the developing frame 40 during the attachment, by inserting the screws 118 having assembled with the second support part 106 and the second reinforcement part 115 into the receiving holes 64 and then attaching the protrusions 108 (layer thickness regulating member 24) to the developing frame 40.
[0183] In the developing frame 40, the parts (the lower end portions 65A of the convex parts 65) corresponding to the deepest parts of the receiving holes 64 are extended up to the opposing surface 66 of the developing frame 40, which opposes the blade 100. Referring to FIG. 3, the seal member 119 is provided at a space (hereinafter, referred to as "gap") between the lower end portions 65A (front end faces of the lower end portions 65A) and opposing surface 66 and the blade 100. Thereby, it is possible to prevent toner from entering the gap. In the developing frame 40, not only the opposing surface 66 but also the front end faces of the lower end portions 65A of the convex parts 65 support the seal member 119. Therefore, it is possible to stabilize the position of the seal member 119 provided at the gap.
[0184] (7) Referring to FIG. 4, the recesses 50 are formed at the parts corresponding to the end edges of the protrusions 108 on the surfaces (front end faces of the left and right screw parts 50) of the developing frame 40, which opposes the layer thickness regulating member 24. Therefore, even when the protrusions 108 having a burr at the end edges are attached to the developing frame 40, the burr is received in the recesses 53. Thus, the burr does not have a bad influence on the attachment precision of the protrusions 108 (layer thickness regulating member 24) to the developing frame 40 (in other words, the positioning precision of the blade 100 to the circumferential surface of the developing frame 40).
[0185] (8) Referring to FIG. 1, in the printer 1, the exposure unit 12 irradiates the circumferential surface of the photosensitive drum 17 with light to expose it thereby forming an electrostatic latent image on the circumferential surface of the photosensitive drum 17. Herein, the light path L from the exposure unit 12 to the photosensitive drum 17 passes between the pair of protrusions 108 (refer to FIG. 4).
[0186] Therefore, it is possible to approach the light path L to the layer thickness regulating member 24 (i.e., developing cartridge 16). Thus, it is possible to reduce the size of the printer 1, by the approached dimension.
[0187] While the present invention has been shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
[0188] In the above illustrative embodiment, in the layer thickness regulating member 24, the second support part 106 of the support member 101 and the second reinforcement part 115 of the reinforcement member 102 are fixed by the screws 118 (refer to FIG. 10). However, the second support part and the second reinforcement part may be fixed (welded) by welding.
[0189] Additionally, in the above illustrative embodiment, the blade 100 is fixed to the first support part 105 by being sandwiched between the first reinforcing part 114 of the reinforcement member 102 and the first support part 105. However, the blade 100 may be fixed to the first support part 105 by welding. In this case, the reinforce member 102 may be omitted.
[0190] In the above illustrative embodiment, the rotation center 83A of the coupling gear 83 is located in the rectangular area Z which is defined by the L-shaped support member 101. However, as shown in FIG. 11, the rotation center 83A of the coupling gear 83 may be located outside the rectangular area Z.
[0191] In addition, as shown in FIG. 4, the pushing part 104, which is the lower end portion (leading end portion) of the blade 100, has the widthwise dimension, which is the substantially same as the widthwise dimension of the rubber roller 22B of the developing roller 22, and the circumferential surface of the rubber roller 22B is pressed over the entire area of the width direction by the pushing part 104. However, as shown in FIG. 12, both widthwise end portions of the lower end portion of the blade 100 may be notched and thus the pushing part 104 has the widthwise dimension smaller than the widthwise dimension of the rubber roller 22B.
[0192] In this case, the pushing part 104 is not contacted to the circumferential surface of the rubber roller 22B over the entire area of the width direction, so that the circumferential surface of the rubber roller 22B has a part in which the pushing part 104 does not contact both widthwise end portions of the rubber roller 22B. Therefore, it is preferable that the widthwise dimension of the pushing part 104 is equal to or greater than the widthwise dimension of an image forming area of the surface of the photosensitive drum 17, on which an electrostatic latent image is formed, and the pushing part 104 contacts an entire part of the developing roller 22 (rubber roller 22B) in the width direction, which contacts the image forming area.
2008-12-04 Developing device and image forming apparatus
2008-12-18 Developing device and image forming apparatus using same
2009-01-08 Developing device and image forming apparatus
2009-01-29 Developer cartridge, developing device and image forming apparatus