EP2863268A1

EP2863268A1 - Developing device, blade unit, and developing device manufacturing method

Info

Publication number: EP2863268A1
Application number: EP14186524.6A
Authority: EP
Inventors: Junichi Yokoi; Hikaru Yoshizumi
Original assignee: Brother Industries Ltd
Current assignee: Brother Industries Ltd
Priority date: 2013-09-30
Filing date: 2014-09-26
Publication date: 2015-04-22
Anticipated expiration: 2034-09-26
Also published as: JP6268884B2; EP2863268B1; JP2015069167A; CN104516242A

Abstract

A developing device (1) includes a developer carrier (2), a blade (41) disposed adjacent to the developer carrier, and a supporter (42) supporting the blade. The blade includes a weld mark (43) joined to the supporter. A dimension of the weld mark in a first direction is greater than a dimension of the weld mark in a second direction perpendicular to the first direction.

Description

TECHNICAL FIELD

Aspects disclosed herein relate to a blade unit in which a blade is joined to a supporting member by welding, a developing device using the blade unit, and a manufacturing method of the developing device.

BACKGROUND

Conventionally, there has been an electrophotographic image forming apparatus that includes a developing device including a developing roller and a blade unit for regulating a thickness of a developer layer held on the developing roller. Further, there has been known a blade unit that includes a blade that contacts the developing roller and a supporting member that holds the blade in an overlapping manner.
In the blade unit, the blade and the holding member are welded to each other at a plurality of locations in a longitudinal direction of the blade, and the blade may be formed with a plurality of spot-like weld marks thereon.

SUMMARY

Nevertheless, like the above-described technique, in a case where the welded portions of the blade and the supporting member have a small spot-like shape, each of the welded portions formed by welding might not have a fixing strength that is strong enough, and therefore, there may be a risk that the blade cannot be fixed to the supporting member securely.
Accordingly, for example, some embodiments of the disclosure provide for a developing device, a blade unit, and a developing device manufacturing method in which a blade may be fixed to a supporting member securely.
According to one or more aspects of the disclosure, a developing device may include a developer carrier, a blade disposed adjacent to the developer carrier, and a supporter supporting the blade. The blade may include a weld mark joined to the supporter. A dimension of the weld mark in a first direction may be greater than a dimension of the weld mark in a second direction perpendicular to the first direction.
According to one or more other aspects of the disclosure, a blade unit may include a blade and a supporter supporting the blade. The blade may include a weld mark joined to the supporter. A dimension of the weld mark in a first direction may be greater than a dimension of the weld mark in a second direction perpendicular to the first direction.
According to one or more other aspects of the disclosure, a manufacturing method for developing device, which may include a developer carrier, a blade disposed adjacent to the developer carrier, and a supporter supporting the blade, may include placing the blade on the supporter and welding including irradiating a laser beam from a welding machine while moving one of the laser beam irradiated from the welding machine and the blade with respect to the other of the laser beam and the blade, and forming a weld mark joined to the supporter. A dimension of the weld mark in a first direction may be greater than a dimension of the weld mark in a second direction perpendicular to the first direction.
According to the aspects of the disclosure, the blade may be fixed to the supporting member more securely as compared with a case where spot-like weld marks are formed.

DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure, needs satisfied thereby, and the objects, features, and advantages thereof, reference now is made to the following descriptions taken in connection with the accompanying drawings.

Fig. 1 is a perspective view depicting a developing device in an illustrative embodiment according to one or more aspects of the disclosure.
Fig. 2 is a sectional view depicting the developing device in the illustrative embodiment according to one or more aspects of the disclosure.
Figs. 3A illustrates a blade unit in the illustrative embodiment according to one or more aspects of the disclosure.
Fig. 3B is an enlarged view of a weld mark in the illustrative embodiment according to one or more aspects of the disclosure.
Fig. 4A is a diagram for explaining a preparation process in a developing device manufacturing method in the illustrative embodiment according to one or more aspects of the disclosure.
Fig. 4B is a diagram for explaining a welding process in the developing device manufacturing method in the illustrative embodiment according to one or more aspects of the disclosure.
Fig. 5 illustrates a laser microscope image of a weld mark formed on a blade in the welding process in the illustrative embodiment according to one or more aspects of the disclosure.
Fig. 6A illustrates a blade unit in a first variation of the illustrative embodiment according to one or more aspects of the disclosure.
Fig. 6B is an enlarged view of a larger weld mark in the first variation of the illustrative embodiment according to one or more aspects of the disclosure.
Fig. 7 illustrates a laser microscope image of a weld mark formed on the blade in the welding process in the first variation of the illustrative embodiment according to one or more aspects of the disclosure.
Fig. 8 illustrates a 3D measuring microscope image of a weld mark formed on the blade in another variation of the illustrative embodiment according to one or more aspects of the disclosure.
Fig. 9A illustrates a blade unit in a second variation of the illustrative embodiment according to one or more aspects of the disclosure.
Fig. 9B is an enlarged view of a weld mark in the second variation of the illustrative embodiment according to one or more aspects of the disclosure.
Fig. 10 illustrates a blade unit in a third variation of the illustrative embodiment according to one or more aspects of the disclosure.
Fig. 11 is a perspective view depicting a blade unit in a fourth variation of the illustrative embodiment according to one or more aspects of the disclosure.
Fig. 12 is a sectional view depicting a developing device in a fifth variation of the illustrative embodiment according to one or more aspects of the disclosure.

DETAILED DESCRIPTION

Next, an illustrative embodiment of the disclosure is described in detail with referent to the accompanying drawings.
As depicted in Fig. 1, a developing device 1 may comprise mainly a developing roller 2 as an example of a developer carrier, a supply roller 3, a blade unit 4, and a developing case 5 that may hold these components.
The developing case 5 may be a container having therein a toner storage chamber 53 capable of storing toner therein, and may have an opening 51 defined in its one surface. The developing case 5 may define an edge of the opening 51 and comprise a blade support surface 52 to which the blade unit 4 may be fixed.
As depicted in Fig. 2, a conveyor member 7 for conveying toner toward the supply roller 3 may be disposed in the toner storage chamber 53. The conveyor member 7 may comprise a shaft portion 71 that may be rotatably supported by the developing case 5, and a film 72 that may rotate on the shaft portion 71 by rotation of the shaft portion 71.
As depicted in Fig. 1, the developing roller 2 may comprise a cylindrical roller body 2A and a shaft 2B that may be inserted into the roller body 2A and may be rotatable integrally with the roller body 2A. The roller body 2A may have elasticity and may be capable of holding toner on its circumferential surface. The developing roller 2 may be disposed to close the opening 51 of the developing case 5. The shaft 2B that may protrude from the roller body 2A in an axial direction of the developing roller 2 may be rotatably supported by the developing case 5.
The supply roller 3 may be disposed inside the developing case 5 with contacting the developing roller 2, and may be rotatably supported by the developing case 5. The supply roller 3 may be configured to supply toner stored in the developing case 5 to the developing roller 2 by its rotation.
The blade unit 4 may comprise a blade 41 and a supporting member 42, as an example of a supporter. The blade 41 may be disposed near the developing roller 2 such that a tip of the blade 41 may be placed on the developing roller 2. The supporting member 42 may hold the blade 41.
The blade 41 may comprise a sheet metal having a rectangular shape elongated in a direction that an axis of the developing roller 2 may extend. That is, a longitudinal direction of the blade 41 is parallel to the axial direction of the developing roller 2, and a direction perpendicular to the longitudinal direction of the blade 41 is perpendicular to the axial direction of the developing roller 2. The blade 41 may be made of metallic material, for example, stainless steel. In other embodiments, for example, the blade 41 may comprise a sheet metal whose surface may have coating including press oil.
For example, the blade 41 may have a thickness of 0.05 to 2.5 mm, a thickness of 0.05 to 0.12 mm, a thickness of 0.05 to 1.00 mm, a thickness of 0.07 to 0.15 mm, or a thickness of 0.08 to 0.12 mm. A dimension of the blade 41 in the longitudinal direction may be greater than a dimension of the roller body 2A of the developing roller 2 in the axial direction, and for example, the blade may have a length of 218 to 270 mm, a length of 220 to 260 mm, or a length of 222 to 250 mm.
The blade 41 may comprise a contact portion 411, which may protrude toward the developing roller 2 and directly contact the roller body 2A of the developing roller 2, on a distal end 41 E of its surface 41 F, facing the developing roller 2, of the blade 41 (see Fig. 2). The contact portion 411 may be made of, for example, rubber and may extend along the longitudinal direction of the blade 41.
The supporting member 42 may be a member for defining a fixing end of the blade 41 as well as holding the blade 41.
The supporting member 42 may be made of metallic material, for example, electrolytic zinc-coated carbon steel sheet. The supporting member 42 may have a thickness greater than the blade 41 and a substantially rectangular shape elongated in the longitudinal direction of the blade 41. The supporting member 42 may extend so as to exceed both ends 413 of the blade 41 in the longitudinal direction of the blade 41.
The supporting member 42 may overlap the other surface of the blade 41 and pinch the blade 41 in conjunction with the blade support surface 52 of the developing case 5 such that the blade 41 is interposed therebetween. The other surface of the blade 41 may be opposite to the surface 4 IF on which the contact portion 411 of the blade 41 may be disposed. More specifically, the blade 41 may be pinched between an edge 42E of the supporting member 42 and an edge 52E of the support surface 52, wherein the edge 42E of the supporting member 42 and the edge 52E of the support surface 52 may be located on the distal end 41 E side of the blade 41. A portion, which may contact the edge 42E of the supporting member 42 and the edge 52E of the blade support surface 52, of the blade 41 may function as a fulcrum when the blade 41 bends.
The blade unit 4 configured as described above may be fixed to the developing case 5 using screws 6 through holes H in the blade 41 and the supporting member 42. In this state, the blade unit 4 may be configured to regulate a thickness of a toner layer held on the developing roller 2 by the contact portion 411 that may contact the rotating developing roller 2.
As depicted in Fig. 3A, the supporting member 42 may comprise a positioning protrusion 421, which may be engaged with the blade 41, at each end portion in the longitudinal direction on its surface that may face the blade 41. The blade 41 may have a pair of openings 412 that may be engaged with the pair of positioning protrusions 421. One of the pair of openings 412 may be a circular opening and the other of the pair of openings 412 may be an elongated opening. The elongated opening of the pair of openings 412 may absorb a dimensional deviation between the two openings 412 and linear expansion of the blade 41 and the supporting member 42 in the longitudinal direction. The blade 41 may be positioned with respect to the supporting member 42 by the engagement of the openings 412 and the corresponding positioning protrusions 421, respectively.
The blade 41 may be welded to the supporting member 42 at a plurality of locations in the longitudinal direction. More specifically, the blade 41 may be joined to the supporting member 42 by laser welding at each portion of the blade 41 outward than each positioning protrusion 421 in the longitudinal direction and a portion of the blade 41 between the positioning protrusions 421 in the longitudinal direction.
The blade 41 may have a first weld mark 43, as an example of a weld mark, which may join the blade 41 and the supporting member 42 at a position between the positioning protrusions 421, and second weld marks 44, as another example of the weld mark, which may join the blade 41 and the supporting member 42 at respective positions more outward than the respective positioning protrusions 421 in the longitudinal direction.
The first weld mark 43 may continue from a vicinity of the one of the openings 412 to a vicinity of the other of the openings 412 along the longitudinal direction of the blade 41.
As depicted in Fig. 3B, in the first weld mark 43, a dimension W1 in the longitudinal direction of the blade 41 (as an example of a first direction) may be longer than a dimension W2 in the direction perpendicular to the longitudinal direction of the blade 41 (e.g., a direction perpendicular to the first direction). In the first weld mark 43, the dimension W1 in the longitudinal direction of the blade 41 may be 1.1 times or greater, more preferably, 1.5 times or greater, and further preferably, 2.0 times or greater, as long as the dimension W2 in the direction perpendicular to the longitudinal direction of the blade 41. In the illustrative embodiment, the dimension W1 of the first weld mark 43 in the longitudinal direction of the blade 41 may be longer enough than the dimension W2 of the first weld mark 43 in the direction perpendicular to the longitudinal direction of the blade 41.
The dimension W1 of the first weld mark 43 in the longitudinal direction of the blade 41 may be within a range of 1.1 to 3.0 times, a range of 1.1 to 2.1 times, or a range of 1.5 to 3.5 times, as long as the dimension W2 of the first weld mark 43 in the direction perpendicular to the longitudinal direction of the blade 41.
For example, the first weld mark 43 may have a dimension of 210 to 250 mm in the longitudinal direction of the blade 41 and a dimension of 0.1 to 0.6 mm in the direction perpendicular to the longitudinal direction of the blade 41.
As depicted in Fig. 3A, the second weld mark 44 may continue from respective vicinities of the openings 412 to respective vicinities of the ends 413 of the blade 41 along the longitudinal direction of the blade 41.
In a similar manner to the first weld mark 43, each second weld mark 44 may have a greater dimension in the longitudinal direction of the blade 41 than a dimension in the direction perpendicular to the longitudinal direction of the blade 41.
Each of the first weld mark 43 and the second weld marks 44 may have a dimension of 0.2 to 250 mm in the longitudinal direction of the blade 41 and a dimension of 0.1 to 6.0 mm in the direction perpendicular to the longitudinal direction of the blade 41. Each of the first weld mark 43 and the second weld mark may have a dimension of 0.1 to 0.4 mm or a dimension of 0.1 to 0.3 mm in the direction perpendicular to the longitudinal direction of the blade 41.
Hereinafter, advantages of the blade unit 4 configured as described above is described.
Each of the first weld mark 43 and the second weld marks 44 formed on the blade 41 may have the greater dimension in the longitudinal direction of the blade 41 than the dimension in the direction perpendicular to the longitudinal direction of the blade 41. Therefore, the blade 41 may be fixed to the supporting member 42 more securely as compared with a case where spot-like weld marks are formed on the blade 41.
In addition, the first weld mark 43 and the second weld marks 44 may be elongated along the longitudinal direction of the blade 41. Therefore, this configuration may reduce a risk that the blade 41 may come apart from the developing roller 2 due to application of a strong force to a particular portion of the blade 41 when the blade 41 is made contact with the developing roller 2.
Next, a manufacturing method of the developing device 1 is described.
When the blade unit 4 is assembled for manufacturing the developing device 1, first, as depicted in Fig. 4A, the blade 41 may be placed on the supporting member 42 (e.g., a preparation process). At that time, the openings 412 in the blade 41 may be engaged with the corresponding positioning protrusions 421, respectively, of the supporting member 42.
Then, the blade 41 and the supporting member 42 may be fastened on a worktable. Thereafter, as depicted in Fig. 4B, while a laser beam 81 irradiated from the welding machine 8 is moved with respect to the blade 41, the laser beam 81 may be irradiated on the blade 41 to weld the blade 41 and the supporting member 42 to each other (e.g., a welding process).
In the illustrative embodiment, the welding machine 8 may be configured to irradiate a portion, which may face the welding machine 8, of an object with a continuous wave laser as the laser beam 81. In other embodiments, for example, another welding machine that may be configured to irradiate the blade 41 with a laser beam by moving a reflector provided inside the welding machine, without moving the welding machine itself, may be used. For example, a fiber laser may be adopted as the continuous wave laser.
In the welding process, by moving the welding machine 8 with the laser beam 81 being continuously irradiated on the blade 41, a weld mark (e.g., the first weld mark 43 and the second weld marks 44) having a greater dimension in the longitudinal direction of the blade 41 than a dimension in the direction perpendicular to the longitudinal direction of the blade 41 may be formed on the blade 41.
At that time, the laser beam 81 may be moved with respect to the blade 41 along the longitudinal direction of the blade 41 from one end portion, in which the circular opening 412 may be defined, to the other end portion, in which the elongated opening 412 may be defined, of the blade 41. The laser beam 81 may be irradiated to each portion that may be apart from each end of the blade 41 and the edges of the openings 412.
Welding starting from the circular opening 412 side as described above may allow the elongated opening 412 to absorb a thermal expansion of the blade 41 that may occur during welding.
As an example, Fig. 5 illustrates a weld mark formed by the welding process using a blade made of stainless steel (e.g., a thickness of 0.1 mm) as the blade 41, a supporting member made of electrolytic zinc-coated carbon steel sheet (e.g., a thickness of 1.2 mm) as the supporting member 42, and a fiber laser welding machine ML-6700A (manufactured by MIYACHI CORPORATION) as the welding machine. In the welding process, a continuous wave laser was used as a laser beam, and the laser beam was moved at a speed of 200 mm/sec with respect to the blade, where a spot diameter of the laser beam was 0.2 mm, and power of the laser beam was 300 W. The weld mark was observed by a laser microscope VK-X200 series (manufactured by KEYENCE CORPORATION).
While the disclosure has been described in detail with reference to the specific embodiment thereof, it is not limited to the specific embodiment. Various changes, arrangements and modifications may be applied to the detailed configuration without departing from the spirit and scope of the disclosure. In the description below, common parts have the same reference numerals as those of the above-described embodiment, and the detailed description of the common parts is omitted.
In the illustrative embodiment, the blade 41 and the supporting member 42 may be welded to each other by moving the laser beam 82 with respect to the blade 41 while the laser beam 81 is continuously irradiated on the blade 41. Nevertheless, the welding method of the blade 41 and the supporting member 42 might not be limited to the specific embodiment. For example, the blade 41 and the supporting member 42 may be welded to each other by moving the laser beam 82 with respect to the blade 42 while the laser beam 81 is intermittently irradiated on the blade 41.
More specifically, as depicted in Figs. 6A and 6B, the blade 41 may have a large weld mark 45 at a plurality of locations in the longitudinal direction, wherein each large weld mark 45 may include a plurality of weld marks 45A arranged in the longitudinal direction. A weld mark 45A may refer to a weld that may be formed by one laser irradiation.
Each weld mark 45 A may have a circular shape. In the large weld mark 45, adjacent weld marks 45A may overlap each other. Thus, in the large weld mark 45, a dimension W3 in the longer-side of the blade 41 may be longer than a dimension W4 in the shorter-side of the blade 41.
To form such a large weld mark 45 on the blade unit 4, in the welding process, while the laser beam 81 such as a pulsed laser or a continuous wave laser is irradiated on the blade 41, the laser beam 81 may be moved with respect to the blade 41 at a speed which may allow to form adjacent weld marks 45A may overlap each other. For example, a fiber laser or an yttrium aluminum garnet ("YAG") laser may be adopted as the pulsed laser.
As an example, Fig. 7 illustrates a weld mark formed on a blade as a result of welding in which a laser beam such as a pulsed laser was moved at a speed of 200 mm/sec with respect to the blade, where a spot diameter of the laser beam was 0.2 mm, a pulse width of the laser beam was 1.0 msec, and power of the laser beam was 400 W. The welding machine, the blade, and the supporting member may be the same as those used in the example depicted in Fig. 5. The weld mark was observed by the VK-X200 series laser microscope (manufactured by KEYENCE CORPORATION).
Fig. 8 illustrates another example in which a plurality of weld marks that are elongated in the longitudinal direction of the blade 41 are arranged along the longitudinal direction. The weld marks illustrated in Fig. 8 may be formed as a result of welding in which a laser beam such as a continuous wave laser was moved at a speed of 200 mm/sec with respect to the blade, where a spot diameter of the laser beam was 0.1 mm, a pulse width of the laser beam was 14 msec, and power of the laser beam was 200 W. The welding machine, the blade, and the supporting member may be the same as those used in the example depicted in Fig. 5. The weld marks were observed by the VR-3000 series One-Shot measuring microscope (manufactured by KEYENCE CORPORATION).
In the illustrative embodiment, each of the weld marks 43 and 44 may have the elongated shape extending in the longitudinal direction of the blade 41 (e.g., the particular direction). Nevertheless, the shape of the weld mark might not be limited to the specific embodiment. For example, as depicted in Figs. 9A and 9B, each weld mark 46 may have an elongated shape extending in the direction perpendicular to the longitudinal direction of the blade 41 (as another example of the first direction).
In each weld mark 46, a dimension W5 in the direction perpendicular to the longitudinal direction of the blade 41 may be longer than a dimension W6 in the longitudinal direction of the blade 41. The weld marks 46 may be formed at a plurality of locations, respectively, in the longitudinal direction of the blade 41.
It may be preferable that ends, which may be located closer to the contact portion 411, of the plurality of weld marks 46 are arranged in a straight line extending parallel to a direction that the contact portion 411 may extend such that force is exerted uniformly on the contact portion of the contact portion 411 and the developing roller 2.
As depicted in Fig. 10, each weld mark 47 may have an elongated shape extending in a direction intersecting the longitudinal direction of the blade 41 or the direction perpendicular to the longitudinal direction of the blade 41 (as a still another example of the first direction).
In the illustrative embodiment, the weld marks (e.g., the first weld mark 43 and the second weld marks 44) may be formed at one location in the direction perpendicular to the longitudinal direction of the blade 41. Nevertheless, the number of locations where the weld marks may be formed might not be limited to the specific embodiment. In other embodiments, for example, two or more weld marks may be formed at respective positions in the direction perpendicular to the longitudinal direction of the blade 41 so as to be arranged along the direction perpendicular to the longitudinal direction of the blade 41.
In the illustrative embodiment, all the weld marks (e.g., the first weld mark 43 and the second weld marks 44) may have the greater dimension in the longitudinal direction of the blade 41 than the dimension in the direction perpendicular to the longitudinal direction of the blade 41. Nevertheless, the shape of the weld marks formed on the blade 41 might not be limited to the specific embodiment. For example, the second weld mark 44 may have a spot-like shape in which a dimension in the longitudinal direction of the blade 41 and a dimension in the direction perpendicular to the longitudinal direction of the blade 41 may be substantially equal to each other. That is, only one of the weld marks formed on the blade 41 may have a greater dimension in the first direction than a dimension in a direction perpendicular to the first direction.
In the illustrative embodiment, the blade 41 may be welded to the supporting member 42 at the plurality of locations. Nevertheless, the method of welding the blade 41 might not be limited to the specific embodiment. In other embodiments, for example, the blade 41 may have the first weld mark 43 and be joined to the supporting member 42 by welding at one location.
In the illustrative embodiment, in the welding process, the laser beam 81 may be moved with respect to the blade 41. Nevertheless, the manner of moving the laser beam 81 with respect to the blade 41 might not be limited to the specific embodiment. In other embodiments, for example, the blade 41 and the supporting member 42 may be moved with respect to the laser beam 81 to move the laser beam 81 with respect to the blade 41 (or the blade 41 may be moved with respect to the laser beam 81).
In still other embodiments, the laser beam 81 and the set of the blade 41 and the supporting member 42 may be moved at the same time.
In the illustrative embodiment, the blade 41 may comprise the contact portion 411 protruding from the blade 41. Nevertheless, the configuration of the blade 41 might not be limited to the specific embodiment. In other embodiments, for example, as depicted in Fig. 13, the blade 41 A might not comprise a contact portion made of, for example, rubber, but may comprise a bent portion 411A in which the distal end portion of the blade 41A may be bent toward the supporting member 42 (e.g., toward a side opposite to the developing roller 2). The bent portion 411A (e.g., the distal end of the blade 41) may directly contact the roller body 2A of the developing roller 2.
In the illustrative embodiment, the distal end portion of the blade 41 may be placed on the developing roller 2, and the blade 41 may be pinched by the supporting member 42 and the developing case 5. Nevertheless, the configuration of the blade unit 4 might not be limited to the specific embodiment. In other embodiments, for example, as depicted in Fig. 12, the supporting member 42 to which the blade 41 may be welded may be fixed to the developing case 5 directly while the supporting member 42 is pinched by the blade 41 and the developing case 5. In the blade unit 4, the distal end portion of the blade 41 (e.g., the contact portion 411) may contact the developing roller 2 from the conveyor member 7 side, and the surface, which may be opposite to the surface 41 F having the contact portion 411 thereon, of the blade 41 may be supported by the supporting member 42.
In the illustrative embodiment, the developing roller 2 comprising the roller body 2A and the shaft 2B may be illustrated as the developer carrier. Nevertheless, in other embodiments, for example, the developer carrier might not be limited to the specific embodiment. In other embodiments, for example, a brush roller, a developing sleeve, or a belt-shaped developer carrier may be adopted as the developer carrier.
In the illustrative embodiment, the contact portion 411 (e.g., the distal end) of the blade 41 may be in directly contact with the roller body 2A of the developing roller 2 (as an example of the developer carrier). Nevertheless, the configuration of the blade might not be limited to the specific embodiment. In other embodiments, for example, the blade may be disposed such that its distal end portion may be substantially 0.1-1.0 mm apart from the roller body 2A.
In the illustrative embodiment, the stainless steel may be adopted as the metallic material for constituting the blade 41. Nevertheless, the material of the blade 41 might not be limited to the specific embodiment. For example, the blade 41 may be made of, for example, steel for springs, phosphor bronze, beryllium copper, or carbon tool steel. In a case where the steel for springs or the carbon tool steel is adopted, a nickel, chromium, or zinc coating may be applied to the blade 41 for rustproof. In the illustrative embodiment, the electrolytic zinc-coated carbon steel sheet may be adopted as the metallic material for constituting the supporting member 42. Nevertheless, the configuration of the supporting member 42 might not be limited to the specific embodiment. In other embodiments, for example, the supporting member 42 may be made of a cold rolled steel plate or a tinplate, or a plate made of one of the cold rolled steel plate and the tinplate whose surface may be applied with treatment such as Parkerizing, chromating, or nickel coating. The supporting member 42 may also have a coating including press oil thereon.

Claims

A blade unit comprising:
a blade (41); and

a supporter (42) supporting the blade,

wherein the blade includes a weld mark (43) joined to the supporter, and a dimension of the weld mark in a first direction is greater than a dimension of the weld mark in a second direction perpendicular to the first direction.
The blade unit according to claim 1, wherein the dimension of the weld mark in the first direction is 1.1 times or greater as long as the dimension of the weld mark in the second direction.
The blade unit according to claim 1 or 2, wherein the first direction is parallel to a longitudinal direction of the blade.
The blade unit according to any one of claims 1 to 3, wherein the blade is made of metallic material and the supporter is made of metallic material.
A developing device comprising:
the blade unit according to any one of claims 1 to 4; and

a developer carrier (2);

wherein the blade (41) is disposed adjacent to the developer carrier.
A manufacturing method for developing device comprising a developer carrier (2), a blade (41) disposed adjacent to the developer carrier, and a supporter (42) supporting the blade, the method comprising:
placing the blade on the supporter; and

welding comprising irradiating a laser beam (81) from a welding machine, while moving one of the laser beam irradiated from the welding machine and the blade with respect to the other of the laser beam and the blade, and forming a weld mark (43) joined to the supporter, a dimension of the weld mark in a first direction being greater than a dimension of the weld mark in a second direction perpendicular to the first direction.
The manufacturing method according to claim 6, wherein the welding comprises irradiating the laser beam such that the dimension of the weld mark in the first direction is 1.1 times or greater as long as the dimension of the weld mark in the second direction.
The manufacturing method according to claim 6 or 7, wherein the welding comprises irradiating a pulse laser and moving at least one of the laser beam and the blade with respect to the other of the laser beam and the blade in the first direction at a speed which allows adjacent weld marks to overlap each other.
The manufacturing method according to claim 6 or 7, wherein the welding comprises irradiating continuous wave laser and moving at least one of the laser beam and the blade with respect to the other of the laser beam and the blade in the first direction.
The manufacturing method according to any one of claims 6 to 9, wherein the first direction is parallel to a longitudinal direction of the blade.