WO2019017553A1

WO2019017553A1 - Developer cartridge and image forming apparatus including the same

Info

Publication number: WO2019017553A1
Application number: PCT/KR2018/002530
Authority: WO
Inventors: Young Chae Kim; Ki Hyun Yoo; Yong Hun Kim; Sang Hoon Lee; Jun Hee Lee
Original assignee: Hp Printing Korea Co., Ltd.
Priority date: 2017-07-21
Filing date: 2018-03-02
Publication date: 2019-01-24
Also published as: KR20190010233A

Abstract

A developer cartridge includes a transporting member rotatably mounted in a cartridge main body to transport a developer. The transporting member includes a first coil spring to transport the developer in a first direction toward the discharge outlet, a second coil spring to transport the developer in a second direction away from the discharge outlet, and a connection wire connecting the first coil spring and the second coil spring, wherein the connection wire rotates when the first coil spring and the second coil spring rotate and is disposed so as to overlap the discharge outlet.

Description

DEVELOPER CARTRIDGE AND IMAGE FORMING APPARATUS INCLUDING THE SAME

An image forming apparatus, particularly, an electrophotographic image forming apparatus, radiates light modulated according to image information to a photosensitive body to form an electrostatic latent image on a surface of the photosensitive body, supplies toner to the electrostatic latent image to develop the same into a visible toner image, transfers the toner image onto a recording medium, and fixes the transferred toner image on the recording medium so as to print an image on the recording medium.

The image forming apparatus includes a developing device used to form a toner image and a developer cartridge for supplying a developer to the developing device.

The developer cartridge contains a developer, and the developer contained in the developer cartridge may be supplied to the developing device through a discharge outlet. To this end, the developer cartridge includes a transporting member used to transport the developer contained therein toward the discharge outlet.

Examples of the transporting member transporting the developer in the developer cartridge include an auger-type transporting member having a rotational axis and a blade around and protruding from the rotational axis, and a spring-type transporting member having a spiral coil shape.

These and/or other aspects will become apparent and more readily appreciated from the following description of the examples, taken in conjunction with the accompanying drawings in which:

FIG. 1 is a schematic structural diagram of an electrophotographic image forming apparatus according to an example;

FIG. 2 is a perspective view of a developer cartridge according to an example;

FIG. 3 is a cross-sectional view of the developer cartridge of FIG. 2 according to an example;

FIG. 4 is a view for describing an operation of the developer cartridge of FIG. 3 according to an example;

FIG. 5 is a view illustrating a spring-type transporting member according to an example;

FIG. 6 is a perspective view for describing an operation of a spring-type transporting member in a developer cartridge, according to an example;

FIGS. 7A and 7B illustrate modified examples of a connection wire;

FIG. 8 illustrates a connection wire according to an example;

FIG. 9 illustrates a portion of a transporting member according to an example;

FIG. 10 is a view for describing an operation of the transporting member of FIG. 9 according to an example;

FIG. 11 is a view for describing an effect of the transporting member of FIG. 9 according to an example;

FIG. 12 illustrates a portion of a transporting member according to an example;

FIG. 13 is a view for describing a transporting member according to an example;

FIGS. 14A and 14B are views for describing a state of a developer stored in a cartridge main body according to an example;

FIG. 15 is a graph comparing weights of a developer discharged from a developer cartridge through a discharge outlet with respect to a number of rotations of the transporting member, according to an example; and

FIG. 16 is a graph showing a variation in torque applied to a rotational driving axis when agglomerated developer exists inside a developer cartridge, according to an example.

Reference will now be made to examples, which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the present examples may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the examples are merely described below, by referring to the figures, to explain aspects. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. Expressions such as "at least one of," when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list.

Hereinafter, examples of a developer cartridge and an electrophotographic image forming apparatus including the developer cartridge will be described with reference to the attached drawings. In the present specification and drawings, elements having substantially the same functions will be labeled with like reference numerals to avoid repeated description.

FIG. 1 is a schematic structural diagram of an electrophotographic image forming apparatus according to an example. The electrophotographic image forming apparatus according to the present example prints a color image by using an electrophotographic method. That is, the image forming apparatus according to the present example is a color image forming apparatus.

Referring to FIG. 1, the image forming apparatus includes a plurality of developing devices 10, an exposure device 50, a transfer device, and a fixing device 80.

The image forming apparatus may further include a plurality of developer cartridges 20 accommodating a developer. The plurality of developer cartridges 20 are respectively connected to the plurality of developing devices 10, and the developer accommodated in the plurality of developer cartridges 20 is supplied to each of the developing devices 10. The plurality of developer cartridges 20 and the plurality of developing devices 10 are attachable to and detachable from a main body 1 and are individually replaceable.

The plurality of developing devices 10 may include a plurality of developing devices 10C, 10M, 10Y, and 10K that are used to form toner images of cyan (C), magenta (M), yellow (Y), and black (K) colors. In addition, the plurality of developer cartridges 20 may include a plurality of developer accommodating units 20C, 20M, 20Y, and 20K respectively accommodating developers of cyan (C), magenta (M), yellow (Y), and black (K) colors to be supplied to the plurality of developing devices 10C, 10M, 10Y, and 10K. However, the scope of the present disclosure is not limited thereto, and additional developer cartridges 20 and developing devices 10 may be included to accommodate and develop developers of other various colors such as light magenta or white in addition to the above-described colors. Hereinafter, an image forming apparatus including the plurality of developing devices 10C, 10M, 10Y, and 10K and the plurality of developer cartridges 20C, 20M, 20Y, and 20K will be described, and unless otherwise described, elements labeled C, M, Y, or K below respectively refer to elements for developing developers of cyan (C), magenta (M), yellow (Y), and black (K) colors.

The developing devices 10 may each include a photosensitive drum 14, on a surface of which an electrostatic latent image is formed, and a developing roller 13 supplying a developer to the electrostatic latent image to develop the electrostatic latent image into a visible toner image. The photosensitive drum 14 is an example of a photosensitive body, on a surface of which an electrostatic latent image is formed, and may include a conductive metal pipe and a photosensitive layer formed on an outer circumference thereof. A charging roller 15 is an example of a charging device charging the photosensitive drum 14 to have a uniform surface potential. Instead of the charging roller 15, a charging brush, a corona charging device, or the like may also be used.

Although not illustrated in FIG. 1, the developing devices 10 may further include a charging roller cleaner for removing a developer or foreign substances such as dust attached on the charging roller 15, a cleaning member 17 for removing a developer remaining on a surface of the photosensitive drum 14 after an intermediate transfer process, and a regulation member for regulating an amount of a developer supplied to a developing region in which the photosensitive drum 14 and the developing roller 13 face each other. Waste developer is accommodated in a waste developer accommodating unit 17a. The cleaning member 17 may be, for example, a cleaning blade that contacts a surface of the photosensitive drum 14 to scrape the developer. Although not illustrated in FIG. 1, the cleaning member 17 may be a cleaning brush that rotates to contact a surface of the photosensitive drum 14 and scrape the developer.

When a mono-component developing method is used, the developer may be a toner. When a dual-component developing method is used, the developer may be a carrier and a toner. Hereinafter, the developing device 10 in which a dual-component developing method is applied will be described.

The developing roller 13 is spaced apart from the photosensitive drum 14. A distance between an outer circumferential surface of the developing roller 13 and an outer circumferential surface of the photosensitive drum 14 may be, for example, several tens to about several hundreds of microns. The developing roller 13 may be a magnetic roller. In addition, the developing roller 13 may have a form in which a magnet is disposed in a rotating developing sleeve. In the developing device 10, toner is mixed with a carrier, and the toner is attached to a surface of a magnetic carrier. The magnetic carrier is attached to a surface of the developing roller 13 and transported to the developing region in which the photosensitive drum 14 and the developing roller 13 face each other. A regulating member (not shown) regulates an amount of the developer transported to the developing region. Via a developing bias voltage applied between the developing roller 13 and the photosensitive drum 14, only the toner is supplied to the photosensitive drum 14 so as to develop an electrostatic latent image formed on a surface of the photosensitive drum 14 into a visible toner image.

When a trickle developing method is used, in order to maintain a uniform amount of a developer in the developing devices 10, a portion of a carrier may be discharged out of the developing devices 10 together with the toner. In this case, the developer accommodated in the developer cartridges 20 may be a carrier and a toner, and the carrier of the developer cartridges 20 may be supplied to the developing devices 10.

The exposure device 50 radiates light modulated according to image information, onto the photosensitive drum 14, to thereby form an electrostatic latent image on the photosensitive drum 14. Examples of the exposure device 50 may be a laser scanning unit (LSU) using a laser diode as a light source or a light-emitting diode (LED) exposure device that uses an LED as a light source.

The transfer device transfers the toner image formed on the photosensitive drum 14, onto a recording medium P. In the present example, a transfer device that uses an intermediate transfer method is used. For example, the transfer device may include an intermediate transfer belt 60, a plurality of intermediate transfer rollers 61, and a transfer roller 70.

The intermediate transfer belt 60 temporarily accommodates the toner image developed on the photosensitive drum 14 of the plurality of developing devices 10C, 10M, 10Y, and 10K. The plurality of intermediate transfer rollers 61 are disposed to face the photosensitive drum 14 of the plurality of developing devices 10C, 10M, 10Y, and 10K, with the intermediate transfer belt 60 therebetween. An intermediate transfer bias used to intermediately transfer the toner image developed on the photosensitive drum 14, to the intermediate transfer belt 60, is applied to the plurality of intermediate transfer rollers 61. Instead of the intermediate transfer rollers 61, a corona transfer device, a pin scorotron transfer device, or the like may be used.

The transfer roller 70 is disposed to face the intermediate transfer belt 60. A transfer bias voltage for transferring the toner image transferred to the intermediate transfer belt 60, to the recording medium P, is applied to the transfer roller 70.

In addition, a cleaning member 75 that removes the developer remaining on a surface of the intermediate transfer belt 60 after the toner image is transferred to the recording medium P may be included. The cleaning member 75 may be, for example, a cleaning blade that contacts a surface of the intermediate transfer belt 60 to scrape the developer. Although not illustrated in FIG. 1, the cleaning member 75 may be a cleaning brush that rotates to contact the surface of the intermediate transfer belt 60 and scrape the developer.

The fixing device 80 fixes the toner image transferred to the recording medium P, on the recording medium P by applying heat and/or pressure to the toner image. The form of the fixing device 80 is not limited to that illustrated in FIG. 1.

According to the above-described configuration, the exposure device 50 radiates a plurality of beams of light modulated according to image information of the colors onto the photosensitive drum 14 of the plurality of developing devices 10C, 10M, 10Y, and 10K to form an electrostatic latent image on the photosensitive drum 14. The electrostatic latent image of the photosensitive drum 14 of the plurality of developing devices 10C, 10M, 10Y, and 10K is developed into a visible toner image by using the C, M, Y, and K developers supplied from the plurality of developer cartridges 20C, 20M, 20Y, and 20K to the plurality of developing devices 10C, 10M, 10Y, and 10K. The developed toner images are sequentially intermediately transferred to the intermediate transfer belt 60. The recording medium P loaded in a feeding unit 90 is transported along a feeding path 91 between the transfer roller 70 and the intermediate transfer belt 60. Due to a transfer bias voltage applied to the transfer roller 70, the toner images that are intermediately transferred onto the intermediate transfer belt 60 are transferred to the recording medium P. When the recording medium P passes through the fixing device 80, the toner images are fixed to the recording medium P by heat and pressure. The recording medium P, with which fixing is completed, is discharged using a discharge roller 92.

The developer accommodated in the developer cartridge 20 is supplied to the developing device 10. When the developer accommodated in the developer cartridge 20 is completely consumed, the developer cartridge 20 may be replaced with a new developer cartridge 20, or a new developer may be filled in the developer cartridge 20.

The image forming apparatus may further include a developer supply unit 30. The developer supply unit 30 receives a developer from the developer cartridge 20 and supplies the same to the developing device 10. The developer supply unit 30 is connected to the developing device 10 via a supply pipe line 40. Although not illustrated in FIG. 1, the developer supply unit 30 may be omitted, and the supply pipe line 40 may directly connect the developer cartridge 20 and the developing device 10.

FIG. 2 is a perspective view of a developer cartridge according to an example. FIG. 3 is a cross-sectional view of the developer cartridge of FIG. 2 according to an example. FIG. 4 is a view for describing an operation of the developer cartridge of FIG. 3 according to an example. FIG. 5 is a view illustrating a spring-type transporting member according to an example. FIG. 6 is a perspective view for describing an operation of a spring-type transporting member in a developer cartridge according to an example.

Referring to FIGS. 2 through 6, the developer cartridge 20 includes a cartridge main body 100 and a transporting member 200 rotatably mounted in the cartridge main body 100.

The cartridge main body 100 has a predetermined inner space where a developer DV (see FIG. 4) is accommodated and a discharge outlet 101 to discharge the developer DV. The discharge outlet 101 is disposed at one end portion of the cartridge main body 100. A shutter portion 102 that selectively blocks discharging of the developer DV is disposed outside the discharge outlet 101.

The transporting member 200 is disposed in the cartridge main body 100, and has a spring-type structure to transport the developer DV. The transporting member 200 includes a first coil spring 210 to transport the developer DV toward the discharge outlet 101.

The first coil spring 210 is rotatably mounted in the cartridge main body 100. For example, a first end portion 211 of the first coil spring 210 is supported by a rotational driving axis 103 formed at one side of the cartridge main body 100, and the first coil spring 210 is rotated by rotation of the rotational driving axis 103.

The first coil spring 210 is configured such that the developer DV is transported in a first direction toward the discharge outlet 101. For example, the first coil spring 210 may be coiled so as to transport the developer DV in the first direction.

The developer DV stored in the cartridge main body 100 is pressurized (i.e., caused to move) toward the discharge outlet 101 via rotation of the first coil spring 210. As the developer DV is pressurized toward the discharge outlet 101 during rotation of the first coil spring 210, a developer DV1 in an area adjacent to the discharge outlet 101 is more solidified than a developer DV2 far from the discharge outlet 101, thus causing agglomeration of the developer DV1.

Even if the developer cartridge 20 is not mounted in an image forming apparatus, vibration may be applied to the developer cartridge 20 while transporting the developer cartridge 20. Here, a pressure may be continuously applied to the developer cartridge 20 in a downward direction by the weight of the developer DV accommodated in the developer cartridge 20, and this may cause the developer DV to gather to a lower portion of the developer cartridge 20 and cause agglomeration of the developer DV accordingly.

By considering the agglomeration of the developer DV as described above, the transporting member 200 according to an example further includes a second coil spring 220.

The second coil spring 220 may be configured to transport the developer DV in a second direction away from the discharge outlet 101. For example, the second coil spring 220 may be coiled in an opposite direction to a coiling direction of the first coil spring 210. A wire diameter of the second coil spring 220 may be identical to that of the first coil spring 210.

By using the second coil spring 220, the developer DV is transported in the second direction away from the discharge outlet 101, thereby reducing agglomeration of the developer DV near the discharge outlet 101.

Referring to FIG. 5, a rotational diameter RD2 of the second coil spring 220 may be smaller than a rotational diameter RD1 of the first coil spring 210. Here, a rotational diameter of a coil spring is defined to be a diameter of a virtual circle formed during rotation of the coil spring. The second coil spring 220 may be disposed within the first coil spring 210.

A length L2 of the second coil spring 220 may be shorter than a length L1 of the first coil spring 210. For example, the length L2 of the second coil spring 220 may be 1/3 or less of the length L1 of the first coil spring 210. Here, a length of a coil spring is defined in a length direction of the cartridge main body 100.

As the length L2 of the second coil spring 220 is shorter than the length L1 of the first coil spring 210, agglomeration of the developer DV may be addressed. At the same time, damage to the developer DV may be prevented and the developer DV may be transported easily.

If the length L2 of the second coil spring 220 is identical to the length L1 of the first coil spring 210, excessive stress may be applied to the developer DV unintentionally due to friction with the second coil spring 220 that is rotating. This may lead to crushing or breaking up of the developer DV. In addition, if the developer DV remaining in the cartridge main body 100 is a predetermined amount or less, the second coil spring 220 may be a factor that hinders easy transportation of the developer DV to the discharge outlet 101.

However, according to the transporting member 200 of the example, the length L2 of the second coil spring 220 is reduced to 1/3 or less of the length L1 of the first coil spring 210 so as to prevent damage to the developer DV or obstruction in transportation of the developer DV, which are malfunctions that may be caused by the second coil spring 220.

Referring to FIG. 4, the first coil spring 210 transports the developer DV in an upper portion and a lower portion of the cartridge main body 100 in the first direction, and the second coil spring 220 transports the developer DV located in a middle portion of the cartridge main body 100 in the second direction. Here, a circulation structure may be provided in which the developer DV is transported by the first coil spring 210 in the first direction again when the developer DV transported by the second coil spring 220 in the second direction reaches an area where the second coil spring 220 is not present.

As described above, due to interaction between the first coil spring 210 and the second coil spring 220, agglomeration of the developer DV may be mitigated by preventing a pressure from continuously acting on the developer DV near the discharge outlet 101 in one direction.

The second coil spring 220 may be formed as a single body with the first coil spring 210. Accordingly, the second coil spring 220 may also rotate when the first coil spring 210 rotates. By forming the second coil spring 220 as a single body with the first coil spring 210, an additional operation of assembling the second coil spring 220 with the first coil spring 210 may be omitted.

The second coil spring 220 may be connected to a second end portion 212 of the first coil spring 210. The second end portion 212 of the first coil spring 210 may be an end portion adjacent to the discharge outlet 101 of the cartridge main body 100.

Referring to FIG. 5, the first coil spring 210 and the second coil spring 220 are formed as a single body, and a connection wire 230 may be disposed between the first coil spring 210 and the second coil spring 220.

A first end portion of the connection wire 230 is connected to the first coil spring 210, and a second end portion of the connection wire 230 is connected to the second coil spring 220. The connection wire 230 rotates when the first coil spring 210 and the second coil spring 220 rotate. The connection wire 230 rotates with respect to a central rotational axis RC3 which is co-axial to a rotational axis RC1 of the first coil spring 210.

A wire diameter of the connection wire 230 may be identical to that of the second coil spring 220 and that of the first coil spring 210.

A rotational diameter RD3 of the connection wire 230 is greater than the rotational diameter RD2 of the second coil spring 220. The rotational diameter RD3 of the connection wire 230 may be identical to or smaller than the rotational diameter RD1 of the first coil spring 210. The rotational diameter RD3 of the connection wire 230 is defined to be a diameter of a virtual circle formed by rotation of the connection wire 230.

Referring to FIG. 6, the connection wire 230 is disposed to overlap the discharge outlet 101 with respect to a length direction of the cartridge main body 100.

As the connection wire 230 rotates, the connection wire 230 passes an area near the discharge outlet 101. Here, the connection wire 230 may contact and pressurize the developer DV agglomerated near the discharge outlet 101 to thereby address the agglomeration of the developer DV. While reducing a pressure applied to the developer DV in an area adjacent to the discharge outlet 101 due to rotation of the second coil spring 220, agglomeration of the developer DV that is already agglomerated near the discharge outlet 101 may be addressed via rotation of the connection wire 230.

As described above, by addressing the agglomeration of the developer DV near the discharge outlet 101 by using the connection wire 230, the developer DV may be discharged through the discharge outlet 101 at a uniform speed.

The connection wire 230 may have a different shape from the first coil spring 210 or the second coil spring 220. For example, the connection wire 230 may have a linear shape extending in the length direction of the cartridge main body 100. A length L3 of the connection wire 230 may be greater than the diameter D of the discharge outlet 101.

As an area where the discharge outlet 101 is formed and a peripheral area therearound in the cartridge main body 100 are planar, the connection wire 230 extending linearly may be used to effectively address agglomeration of the developer DV in the area where the discharge outlet 101 is formed and the peripheral area therearound.

However, the shape of the connection wire 230 is not limited thereto, and may be modified in various structures as long as it addresses agglomeration of the developer DV. For example, as illustrated in FIG. 7A or 7B, the shape of

connection wires

230A and 230B may be a zigzag shape or a wave shape.

FIG. 8 illustrates a connection wire according to an example.

Referring to FIG. 8, the connection wire 230C may have magnetic force. For example, a magnet 231 may be mounted on the connection wire 230C.

The developer DV stored in the cartridge main body 100 may be a dual-component developer DV. For example, the developer DV may include a carrier CA and a toner.

Due to the magnetic force of the connection wire 230C, the carrier CA may be attracted to or attached to a surface of the connection wire 230C. A rotational area of the connection wire 230C increases due to the carrier CA attached to the surface of the connection wire 230C. The connection wire 230C having the carrier CA attached thereto may perform the function of a brush sweeping the developer DV around the discharge outlet 101. Accordingly, the developer DV may be easily discharged through the discharge outlet 101 by using the connection wire 230C.

FIG. 9 illustrates a portion of a transporting member according to an example. FIG. 10 is a view for describing an operation of the transporting member of FIG. 9 according to an example. FIG. 11 is a view for describing the effect of the transporting member of FIG. 9 according to an example. FIG. 12 illustrates a portion of a transporting member according to an example.

Referring to FIG. 9, the transporting member 200 includes a first coil spring 210, a second coil spring 220A, and a connection wire 230 connecting the first coil spring 210 and the second coil spring 220A.

A wire diameter d2 of a first area 2201 of the second coil spring 220A connected to the connection wire 230 may be smaller than a wire diameter of other portions of the transporting member 200. For example, in the second coil spring 220A, the wire diameter d2 of the first area 2201 connected to the connection wire 230 may be smaller than a wire diameter d3 of a second area 2202 which is another region of the second coil spring 220A. The wire diameter d2 of the first area 2201 of the second coil spring 220A may be smaller than a wire diameter d1 of the connection wire 230. The wire diameter d2 of the first area 2201 of the second coil spring 220A may be smaller than the wire diameter of the first coil spring 210.

As described above, as the wire diameter d2 of the first area 2201 of the second coil spring 220A is smaller than a wire diameter of other portions of the transporting member 200, tension may be concentrated on the first area 2201 when the transporting member 200 rotates. Accordingly, movement of the second coil spring 220A may be extended.

Referring to FIG. 10, when the transporting member 200 rotates, the second coil spring 220A moves back and forth with respect to the connection wire 230, and a rotational axis RC2 of the second coil spring 220A may be varied.

Referring to FIG. 11, as the rotational axis RC2 of the second coil spring 220A is varied, transportation directions A1 and A2 of the developer DV transported using the second coil spring 220A may be varied. As the transportation directions A1 and A2 of the developer DV are varied by the second coil spring 220A, the transportation directions A1 and A2 of the developer DV transported using the second coil spring 220A may intersect with a transporting direction of the developer DV transported using the first coil spring 210, and accordingly, the developer DV may be easily mixed in a section where the first coil spring 210 and the second coil spring 220A overlap each other.

In FIGS. 9 through 11, as an example for easy mixing of the developer DV, the focus of description was on an example in which the wire diameter d2 of the first area 2201 of the second coil spring 220 is smaller than a wire diameter of other portions of the transporting member 200. However, a structure of the transporting member 200 that allows to easily mix the developer DV is not limited, and may be modified in various structures. For example, as illustrated in FIG. 12, a first coil spring 210, a second coil spring 220B, and a connection wire 230 have identical diameters, and may be bent such that an acute angle (θ) is formed between a rotational axis RC2 of the second coil spring 220B and a rotational axis RC1 of the first coil spring 210.

FIG. 13 is a view for describing a transporting member according to an example. FIGS. 14A and 14B are views for describing a state of a developer DV stored in a cartridge main body according to an example.

Referring to FIG. 13, the transporting member 200 may include a first coil spring 210, a second coil spring 220, and a connection wire 230D connecting the first coil spring 210 and the second coil spring 220. The connection wire 230D is disposed to overlap a discharge outlet 101.

A surface roughness of the connection wire 230D may be higher than that of the second coil spring 220 and may be higher than that of the first coil spring 210. For example, when the surface roughness of the first coil spring 210 and the second coil spring 220 are 0.7 Ra to 0.8 Ra, a surface roughness of the connection wire 230D may be about 3.2 Ra to 6.3 Ra.

By setting a high surface roughness of the connection wire 230D disposed to overlap the discharge outlet 101, triboelectrification occurs more in the developer DV near the discharge outlet 101 than the developer DV in other areas. Accordingly, toner TN is attached to the carrier CA more easily in the developer DV near the discharge outlet 101 as illustrated in FIG. 14A than in the developer DV in other regions as illustrated in FIG. 14B.

By discharging the developer DV that is put into an triboelectrified state as described above through the discharge outlet 101, the time period during which the developer DV is triboelectrified in the developing device 10 may be reduced.

Moreover, by setting a relatively low surface roughness of the other regions of the transporting member 200 that do not overlap the discharge outlet 101, friction charging of the developer DV in the other regions that are not adjacent to the discharge outlet 101 may be reduced, and thus, breaking up or crushing of the developer DV due to excessive frictional charging may be prevented.

Examples of the present disclosure will be described in more detail by referring to a comparative example below. However, the example is described for illustration and does not limit the scope of the present disclosure.

Comparative Example

A developer cartridge according to the comparative example includes a cartridge main body 100 having a discharge outlet 101 at one side and a transporting member that is rotatably mounted in the cartridge main body 100 and includes a first coil spring 210 transporting a developer in a direction toward the discharge outlet 101. The transporting member according to the comparative example does not include the second coil spring 220 and the connection wire 230.

Example Embodiment

The developer cartridge 20 according to an example includes a cartridge main body 100 having a discharge outlet 101 at one side and a transporting member 200 rotatably mounted in the cartridge main body 100. The transporting member 200 has a structure in which a first coil spring 210 transporting a developer in a direction toward the discharge outlet 101, a second coil spring 220 transporting a developer away from the discharge outlet 101, and a connection wire 230 connecting the first coil spring 210 and the second coil spring 220 are formed as a single unit. Wire diameters and surface roughness of the first coil spring 210, the second coil spring 220, and the connection wire 230 are substantially identical, the second coil spring 220 and the first coil spring 210 are coaxial, and the connection wire 230 is formed to have a linear shape.

Characteristics

Evaluation

1

Each time the transporting member rotates 2500 times, the weight of the developer discharged from the developer cartridge through the discharge outlet 101 was measured and the result is shown in FIG. 15 and Table 1 below.

FIG. 15 is a graph comparing weight of a developer discharged from a developer cartridge through a discharge outlet with respect to a number of rotations of the transporting member, according to an example.

	2500 times	5000 times	7500 times	10000 times	12500 times
Comparative Example	97 g	150 g	163 g	305 g	340 g
Example Embodiment	150 g	310 g	460 g	640 g	720 g

Referring to FIG. 15 and Table 1, in the developer cartridge according to the comparative example, the weight of the developer discharged with every 2,500 rotations of the transporting member varies considerably. For example, as the number of rotations of the transporting member exceeds 2,500 times to reach 5,000 times, the weight of the discharged developer is about 13 g (= 163 - 150), whereas the weight of the discharged developer is about 142 g (= 305 - 163) during a period from when the number of rotations of the transporting member exceeds 7,500 times until it reaches 10,000 times. That is, in the developer cartridge of the comparative example, even when the transporting member rotates 2,500 times equally, the maximum weight of the discharged developer was ten times or more the minimum weight of the discharged developer.

On the other hand, in the developer cartridge 20 of the example, the weight of the developer being discharged at 2500 rotations of the transporting member 200 was about 80 g to about 180 g. That is, in the developer cartridge 20 of the example embodiment, the maximum weight of the discharged developer was 2.5 times or less the minimum weight of the discharged developer.

As shown above, by including the transporting member 200 in which the connection wire 230 and the second coil spring 220 are formed as a single unit with the first coil spring 210 as in the developer cartridge 20 according to the example, the developer may be discharged through the discharge outlet 101 at a predetermined speed range.

Characteristics

Evaluation

2

The developer cartridges according to the comparative example and the example were positioned upright such that the rotational driving axis 103 faced upward, and vibration was applied thereto for a predetermined period of time to induce agglomeration of the developer contained in the developer cartridge.

Referring to FIG. 16, during an operation of driving the rotational driving axis while the agglomerated developer exists in the developer cartridge, torque applied to the rotational driving axis increases rapidly until the transporting member starts rotating. When the transporting member rotates to dissolve the agglomerated developer, the torque applied to the rotational driving axis is reduced. After the agglomeration of the developer is mitigated to some extent, the torque applied to the rotational driving axis is uniform. When torque applied to the transporting member with no agglomerated developer is referred to as normal torque, a time period T from a point t1 when greater torque than the normal torque is applied, to a point t2 where smaller torque than the normal torque is applied is defined as a time period taken for resolution of the agglomeration of the agglomerated developer.

While the agglomerated developer is accommodated in the developer cartridge of the comparative example and the example, when the transporting member is rotated, the time period T taken for resolution of the agglomeration of the agglomerated developer was measured and the result is shown as in Table 2.

	Time Taken for Resolution of Agglomeration after Vibration Is Applied (seconds)
	10 minutes of vibration	20 minutes of vibration	30 minutes of vibration
Comparative Example	10 seconds	14 seconds	22 seconds
Example Embodiment
	6 seconds	9 seconds	10 seconds

Referring to Table 2, in the developer cartridge of the comparative example, as the period of vibration applied to the developer cartridge is increased as 10, 20, and 30 minutes, the time needed for resolution of the agglomeration of the agglomerated developer was 10, 14, and 22 seconds, respectively. According to the developer cartridge of the example, as the period of vibration applied to the developer cartridge is increased as 10, 20, and 30 minutes, the time needed for resolution of the agglomeration of the agglomerated developer was 6, 9, and 10 seconds, respectively.

This shows that even when the developer accommodated in the developer cartridge of the example and the developer cartridge of the comparative example are equally in an agglomerated state, the time needed for resolution of the agglomeration of the developer of the example is less than that of the developer cartridge of the comparative example by about 45% to about 64%.

According to the developer cartridge of the example and the image forming apparatus including the developer cartridge, while using a spring-type transporting member, agglomeration of the developer may be addressed, and the developer may be discharged at a uniform speed.

It should be understood that examples described herein are to be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each example should typically be considered as available for other similar features or aspects in other example.

While one or more examples have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope as defined by the following claims.

Claims

A developer cartridge comprising:

a cartridge main body accommodating a developer and including a discharge outlet through which the developer is dischargeable to the outside of the cartridge main body; and

a transporting member rotatably mounted in the cartridge main body to transport the developer,

wherein the transporting member comprises:

a first coil spring to transport the developer in a first direction toward the discharge outlet;

a second coil spring having a rotational diameter smaller than a rotational diameter of the first coil spring, wherein the second coil spring rotates when the first coil rotates and transport the developer in a second direction away from the discharge outlet; and

a connection wire including a first end portion and a second end portion, the first end portion connected to the first coil spring, and the second end portion connected to the second coil spring, wherein the connection wire rotates when the first coil spring and the second coil spring rotate and is disposed so as to overlap the discharge outlet.
The developer cartridge of claim 1, wherein the connection wire extends linearly along a length direction of the cartridge main body.
The developer cartridge of claim 1, wherein a rotational diameter of the connection wire is greater than the rotational diameter of the second coil spring.
The developer cartridge of claim 3, wherein the rotational diameter of the connection wire is equal to or smaller than the rotational diameter of the first coil spring.
The developer cartridge of claim 1,

wherein the developer comprises a dual-component developer including a carrier and a toner, and

wherein the connection wire has magnetic force that attracts the carrier.
The developer cartridge of claim 1, wherein a surface roughness of the connection wire is higher than a surface roughness of the second coil spring.
The developer cartridge of claim 1, wherein a length of the second coil spring is shorter than a length of the first coil spring.
The developer cartridge of claim 7, wherein the length of the second coil spring is one third or less than the length of the first coil spring.
The developer cartridge of claim 1, wherein a wire diameter of a portion of the second coil spring connected to the connection wire is smaller than a wire diameter of other portions of the second coil spring.
The developer cartridge of claim 1, wherein the second coil spring is disposed such that an angle between a central rotational axis of the second coil spring and a central rotational axis of the first coil spring is an acute angle.
A developer cartridge comprising:

a cartridge main body accommodating a developer and having a discharge outlet through which the developer is dischargeable to the outside; and

a transporting member rotatably mounted in the cartridge main body to transport the developer,

wherein the transporting member comprises:

a first coil spring to transport the developer in a first direction toward the discharge outlet; and

a second coil spring connected to the first coil spring and having a rotational diameter smaller than a rotational diameter of the first coil spring, wherein the second coil spring rotates when the first coil rotates and transport the developer in a second direction away from the discharge outlet,

wherein a length of the second coil spring is shorter than a length of the first coil spring.
The developer cartridge of claim 11, wherein a length of the second coil spring is one third or less than a length of the first coil spring.
The developer cartridge of claim 11, wherein the second coil spring is disposed such that an angle between a central rotational axis of the second coil spring and a central rotational axis of the first coil spring is an acute angle.
An image forming apparatus comprising:

a developing device to supply a developer to an electrostatic latent image formed on a photosensitive drum, so as to form a visible toner image;

a developer cartridge to supply the developer to the developing device;

a transfer device to transfer the toner image to a recording medium; and

a fixing device to fix the toner image to the recording medium,

wherein the developer cartridge comprises:

a cartridge main body accommodating the developer and including a discharge outlet through which the developer is dischargeable to the outside of the cartridge main body; and

a transporting member rotatably mounted in the cartridge main body to transport the developer, and

wherein the transporting member comprises:

a first coil spring to transport the developer in a first direction toward the discharge outlet;

a second coil spring having a rotational diameter smaller than a rotational diameter of the first coil spring, wherein the second coil spring rotates when the first coil rotates and transport the developer in a second direction away from the discharge outlet; and

a connection wire including a first end portion and a second end portion, the first end portion connected to the first coil spring, and the second end portion connected to the second coil spring, wherein the connection wire rotates when the first coil spring and the second coil spring rotate and is disposed so as to overlap the discharge outlet.