WO2008056912A1

WO2008056912A1 - Device for installing and separating drum from cartridge for display forming apparatus

Info

Publication number: WO2008056912A1
Application number: PCT/KR2007/005500
Authority: WO
Inventors: Jin Seok Lee; Bum Jin Lee
Original assignee: Baiksan OPC Co Ltd
Current assignee: Baiksan OPC Co Ltd
Priority date: 2006-11-08
Filing date: 2007-11-01
Publication date: 2008-05-15
Anticipated expiration: 2009-05-08
Also published as: KR200437165Y1

Abstract

The present invention provides a device for installing a drum to a cartridge having at least one fixing hole for an image forming apparatus, comprising: a cylinder having at least one protrusion protruded on the outer surface at one end portion of the cylinder, wherein the protrusion interferes the edge of the drum so that the one end portion of the cylinder cannot be inserted into the inside of the drum while the other end portion of the cylinder can be inserted into the inside of the drum, and wherein an accommodating space is formed in the cylinder as having an opening toward the outside of the drum; a shaft installed movable in the accommodating space in the longitudinal direction so that the one end of the shaft can be protruded out of the opening or the one end of the shaft can be concealed into the accommodating space; and at least one elastic member for pushing the shaft so that the one end of the shaft be forced to be protruded out of the opening; wherein the one end of the shaft protruded to the outside of the edge of the drum is inserted into the fixing hole of the cartridge whereby the drum is rotatably supported, whereby the drum can be simply and easily installed to the cartridge without an excessive load applied to the drum during the installation, and further, the drum can be easily separated from the cartridge without any damages.

Description

DEVICE FOR INSTALLING AND SEPARATING DRUM FROM CARTRIDGE FOR DISPLAY FORMING APPARATUS

Technical Field

[1] The present invention relates to a device for installing and separating a drum from a cartridge for an image forming apparatus, more particularly, to such a device for an electronic image forming apparatus realizing a simple and easy installation of the electrophotographic photosensitive drum (hereinafter, referred to simply as "drum") to the process cartridge (hereinafter, referred to simply as "cartridge") as well as for realizing a simple and easy separation of the drum from the cartridge without difficult work such as cutting the drum when the drum is required to be changed by new one.

[2]

Background Art

[3]

[4] In general, an image forming apparatus forms characters or images on papers such as copier, laser printer, ink jet printer, LED printer or facsimile. The image forming apparatus necessarily includes at least one cartridge to form characters or images. And the cartridge generally comprises an organic photo conductor (OPC) drum, a conditioning unit, a cleaning unit, a writing unit and a developing unit.

[5] The image forming apparatus comprised above is operated by the following processes. That is, when a charge reaches the OPC drum, The OPC drum is exposed to light and the exposed area of the OPC drum is upset by toner, and then, the toner on the exposed are of the OPC drum is transferred onto a paper. Herein, by heating the OPC drum and the paper, the transferred image on the paper is stably adhered.

[6] The OPC drum (hereinafter, referred to simply as "drum") is main component of the image forming apparatus, and the toner upset on its surface is transferred to paper as the drum is rotated driven by the cartridge.

[7] As shown in Fig. 1, a drum shaft 30 combined with one end surface of the drum 10 is inserted as an idler into a fixing hole 2 of the cartridge 2' and the other drum shaft 11 is also inserted as a driven one into the other fixing hole 2 thereof, whereby the drum can be rotatably supported in the cartridge.

[8] Herein, the one side 30 of the drum 10 is combined with a flange 31 having the drum shaft 30.

[9] On the other hand, during the process of transferring the upset toner onto a paper, high pressure is applied on the drum 10. Further, as the high pressure is transferred to the shaft 11, 30 of the drum 10, high friction heat is generated whereby the drum 10 itself as well as drum shaft 11, 30 may be deformed or damaged. Therefore, after using the drum 10 for a predetermined period the drum 10 is required to be changed by new one.

[10] However, as shown in Fig. 1, in case that the flange 31 is inseparably combined with the drum 10 or that the flange 31 is combined with the drum 10 with permanent assembly method such as bonding or compulsory tight fitting (e.g., zero or minus tolerance), a troublesome work such as drum cutting is necessarily required to change the drum.

[11] Similarly, in case that the only drum shaft 11, 30 is required to be changed, even though the life-time of the drum 10 still remains, the drum cannot be used after the change of the drum shaft 11, 30 because the drum 10 should be cut for changing the drum shaft 11, 30. Otherwise, as the cartridge should be fully dissembled so as to change the drum shaft 11, 30, it is a realistically impossible work in view of economics and the difficulty of the changing work. Further, as the drum still remaining life-time should be removed, there was problem to cause the environmental pollution and the excessive maintaining cost. Disclosure of Invention Technical Problem

[12] In order to overcome these disadvantages of the prior art, the present invention has an object to provide a device for easily installing a drum to a cartridge for an image forming apparatus and also for easily separating the drum from the cartridge therefor without troublesome work such as drum cutting process or compulsory separation of the tight fitting portion.

[13] The present invention also has an object to install the drum to the cartridge only by separable combinations such as inserting or normal fitting or fastening and by excluding substantially permanent assemblies such as bonding, welding or tight fitting.

[14] Further, the present invention has an object to solve problems that the assembled quality can be different depending on the skill of workers by excluding permanent assembly method which requires the precise skill thereon.

[15] Also, the present invention has an object that all components can be reused after the disassembly of the drum by preventing physical damages during the disassembly of the drum.

[16] Yet, the present invention has an object to construct the device for installing a drum to a cartridge and for separating the drum from the cartridge as a module thereby realizing easy handling of the components as well as the reduction of the manufacture time and cost. Technical Solution [17] In order to attain the above mentioned object, the present invention provides a device for installing a drum to a cartridge having at least one fixing hole for an image forming apparatus, comprising: a cylinder having at least one protrusion protruded on the outer surface at one end portion of the cylinder, wherein the protrusion interferes the edge of the drum so that the one end portion of the cylinder cannot be inserted into the inside of the drum while the other end portion of the cylinder can be inserted into the inside of the drum, and wherein an accommodating space is formed in the cylinder as having an opening toward the outside of the drum; a shaft installed movable in the accommodating space in the longitudinal direction so that the one end of the shaft can be protruded out of the opening or the one end of the shaft can be concealed into the accommodating space; and at least one elastic member for pushing the shaft so that the one end of the shaft be forced to be protruded out of the opening; wherein the one end of the shaft protruded to the outside of the edge of the drum is inserted into the fixing hole of the cartridge whereby the drum is rotatably supported.

[18] That is, as the drum is rotatably fixed to the cartridge only by using an elastic force or a relative interferences between components instead of permanent assembly method, the drum can be simply and easily installed to the cartridge without an excessive load applied to the drum during the installation, and further, the drum can be easily separated from the cartridge without any damages.

[19] In order that the shaft is not more protruded through the opening than a predetermined length, at least one interference part may be formed at at least one of the shaft and the cylinder where the one end of the shaft is protruded by a predetermined length. Herein, the interference part is formed as a step which causes the interference between the shaft and the cylinder, whereby the protruded length of the shaft can be maintained consistently even though an operator does not handle the protruded length of the shaft.

[20] Further, in order that the protruded length of the shaft can be stably maintained by the predetermined length, a pair of screws engaged with each other for fixing the relative position between the shaft and the cylinder are formed. Concretely, the pair of screws are formed as male screw on the outer surface of the shaft and as female screw on the inner surface of cylinder at a position where the one end of the shaft is protruded by the predetermined length. Thus, when the relative position between the shaft and the cylinder (i.e., protruded length of the shaft) is maintained by the pair of the screws, although external force is applied to push the shaft to the inside of the drum, as the shaft can be firmly protruded by the predetermined length, the process of insertion of the shaft into the fixing hole of the cartridge can be done without any difficulties or delay.

[21] Similarly, in order that the shaft is maintained as being concealed in the ac- commodating space, a pair of screws engaged with each other for fixing the relative position between the shaft and the cylinder at a position where the one end of the shaft is concealed into the accommodating space. Concretely, the pair of screws are formed as male screw on the outer surface of the shaft and as female screw on the inner surface of cylinder at a position where the one end of the shaft is concealed into the ac commodating space. Therefore, in case that the drum is to be separated from the cartridge, by fixing the shaft as being concealed in the accommodating space by the pair of screws, in spite of the elastic force to consistently push the shaft to be protruded out of the opening of the accommodating space, the process of the separation of the drum from the cartridge is more convenient and easy.

[22] Herein, "+" shaped groove or "-" shaped groove is formed on the one end surface of the shaft so that the shaft can be easily rotated by a screwdriver, thereby realizing easy fastening or releasing of the pairs of screws between the shaft and the cylinder.

[23] Meanwhile, the present invention provides a device for installing a drum to a cartridge having at least one fixing hole for an image forming apparatus, comprising: a cylinder having a flange protruded on the outer surface at one end portion of the cylinder, wherein the flange interferes the edge of the drum so that the one end portion of the cylinder cannot be inserted into the inside of the drum while the other end portion of the cylinder can be inserted into the inside of the drum, the cylinder being formed as having an accommodating space penetrating the cylinder in the longitudinal direction and having a step on the inner wall of the accommodating space such that the inside opening at the other end of the cylinder is larger than the outside opening at the one end of the cylinder; a shaft installed movable in the accommodating space in the longitudinal direction so that the one end of the shaft can be protruded out of the outside opening or the one end of the shaft can be concealed into the accommodating space, the shaft having at least one protrusion protruded on the outer surface so that the protrusion is interfered with the step for limiting the movement of the shaft, wherein at least one groove is formed on the one end surface of the shaft so that the groove is engaged with a screwdriver; a back member fixed at the inner opening of the cylinder so that the shaft in the accommodating space cannot be out of the accommodating space; and at least one elastic member located between the shaft and the back member for pushing the shaft to the outside of the drum so that the one end of the shaft be forced to be protruded out of the outside opening; wherein the one end of the shaft protruded to the outside of the edge of the drum is inserted into the fixing hole of the cartridge whereby the drum is rotatably supported.

[24] From the above construction, as the cylinder, the shaft, the backing member and the elastic member constitute a module, the handling and assembly work of the components is more convenient and easier during the installation of the drum to the cartridge.

[25] On the meantime, the present invention provides a device for installing a drum to a cartridge having at least one fixing hole for an image forming apparatus, comprising: a shaft having at least one guide projection protruded on the outer wall and having at least one grip portion to be caught from the one end of the shaft; a first cylinder having at least one protrusion on the outer surface at one end portion of the first cylinder, wherein the protrusion interferes the edge of the drum so that one end portion of the first cylinder cannot be inserted into the inside of the drum while the other end portion of the first cylinder can be inserted into the inside of the drum, the first cylinder being formed as a hollow pipe so that the fixing hole communicates with the inside of the first cylinder, wherein at least one locking groove is formed in the circumferential direction at the other end portion of the first cylinder so that the protrusion can be inserted; a second cylinder being located in the inside of the drum by being combined with the other end portion of the first cylinder, the second cylinder having accommodating space for accommodating the shaft wherein at least one guide groove is formed on the inner surface of the second cylinder so that the at least one guide projection of the shaft is inserted to the guide groove to guide the shaft movable in the accommodating space in the longitudinal direction whereby the one end of the shaft can be protruded out of the first cylinder or the one end of the shaft can be concealed into the accommodating space; wherein the guide groove and the locking groove are connected with each other when the first cylinder and the second cylinder are combined with each other so that the guide projection can move between the guide groove and the locking groove, and wherein the one end of the shaft protruded to the outside of the edge of the drum is inserted into the fixing hole of the cartridge whereby the drum is rotatably supported.

[26] That is, as the guide projection of the shaft moves along the guide groove of the second cylinder with being inserted into the guide groove, the shaft moves in the longitudinal direction of the second cylinder. Then, when the shaft is protruded from the first cylinder by a predetermined length, the guide projection of the shaft moves along from the longitudinal guide groove of the second cylinder to the circumferential locking groove of the first cylinder (i.e., the shaft is rotated), and thus, even though any external force is applied to the shaft to be concealed, the protruded condition of the shaft can be maintained, whereby the shaft rotatably supporting the drum can be stably inserted to the fixing hole of the cartridge. Also, by separately manufacturing the first cylinder and the second cylinder, the first cylinder and the second cylinder can be easily manufactured with lower cost such by an injection molding method.

[27] Herein, the shaft has an inner space and the grip portion is formed as a bar to be connected with the inner wall of the shaft. Thus, when the shaft is tried to be protruded from the first cylinder or to be concealed to the second cylinder, it is easier for an operator to handle the shaft such as pushing or pulling by hooking the grip portion through the fixing hole.

[28] In order to firmly maintain the protruded state of the shaft, at least one extending groove is formed on the inner wall of the first cylinder as at least one bent path from the locking groove. Herein, it is enough that the extending groove is formed as having more than one bent point. However, in case that the number of the bent point thereof is more than two, at least one of the bent points is formed as being bent less than 90 degree so as to obtain enough friction between the guide groove and the guide projection.

[29] Therefore, the extending groove is formed as having at least one bent point, of which one path is formed in the circumferential direction thereby stably maintaining the installed condition of the drum in spite of any longitudinal external force.

[30] Also, at least one engaging portion is formed at least one of the first cylinder and the second cylinder so that the guide groove and the extending groove is connected each other. That is, if only the engaging portion of the first cylinder and of the second cylinder are combined each other, the guide groove and the extending groove are connected each other. Herein, the engaging portion can be hole(s) and protrusion(s) on the facing surface thereof or can be a pair of screws engaged with each other so as to communicate the guide groove with the extending groove.

[31] Meanwhile, the first cylinder and the second cylinder of the present invention can be one body. That is, the present invention also provides a device for installing a drum to a cartridge having at least one fixing hole for an image forming apparatus, comprising: a shaft having at least one guide projection protruded on the outer wall and having at least one grip portion to be caught from the one end of the shaft; and a cylinder having at least one protruded interfering portion on the outer surface at one end portion, wherein the interfering portion interferes the edge of the drum so that one end portion of the first cylinder cannot be inserted into the inside of the drum while the other end portion of the first cylinder can be inserted into the inside of the drum, the cylinder having an accommodating space for accommodating the shaft, wherein at least one guide groove is formed on the inner surface of the cylinder so that the at least one guide projection of the shaft is inserted the guide groove to guide the shaft movable in the accommodating space in the longitudinal direction whereby the one end of the shaft can be protruded out of the cylinder or the one end of the shaft can be concealed into the accommodating space; wherein the one end of the shaft protruded to the outside of the edge of the drum is inserted into the fixing hole of the cartridge whereby the drum is rotatably supported.

[32] Herein, the grip portion is formed as a bar connected with the inner walls facing with each other of the shaft.

[33] Also, when the shaft is protruded by the predetermined length so as to be inserted to the fixing hole, the guiding groove is connected to the extending groove having one more bent point thereby fixing the shaft more firmly.

[34] Meanwhile, the present invention provides a device for installing a drum to a cartridge having at least one fixing hole for an image forming apparatus, comprising: a cylinder having at least one protrusion on the outer surface at one end portion so that the protrusion is interfered with the edge of the drum whereby the other end portion of the cylinder is inserted into the inside of the drum while the one end portion of the cylinder is not inserted into the inside of the drum, the cylinder having an accommodating space with an opening at the one end portion of the cylinder so that the accommodating space communicates with the fixing hole, wherein at least one guide rail is formed on the inner surface of the accommodating space for guiding the shaft to move in the longitudinal direction; a shaft installed movable in the accommodating space in the longitudinal direction so that the one end of the shaft can be protruded out of the cylinder or the one end of the shaft can be concealed into the accommodating space, the shaft having at least one interfering protrusion formed on the outer surface of the shaft for being interfered with the guide rail wherein at least one rail groove for accommodating the guide rail is formed at the interfering protrusion whereby the shaft can move in the longitudinal direction only when the rail groove is engaged with the guide rail; and an elastic member for exerting elastic force on the shaft so that the shaft is protruded out of the cylinder; wherein the shaft can be rotated by the release of the engagement between the rail groove and the guide rail when the shaft is concealed in the accommodating space, and the one end of the shaft protruded to the outside of the edge of the drum is inserted into the fixing hole of the cartridge whereby the drum is rotatably supported.

[35] Therefore, the installation or assembling of the drum to the cartridge can be efficiently done within a short time by excluding screws requiring lots of time for operator to handle. Further, as the guide rail(s) which is easy to be manufactured is formed on the inner surface of the accommodating space, the shaft can be stably concealed in the accommodating space by the interferences with the guide rail and further can be guided in the straightly longitudinal direction.

[36] On the other hand, the present invention further provides a device for installing a drum to a cartridge having at least one fixing hole for an image forming apparatus, comprising: a cylinder having a flange on the outer surface at one end portion so that the protrusion is interfered with the edge of the drum whereby the other end portion of the cylinder is inserted into the inside of the drum while the one end portion of the cylinder is not inserted into the inside of the drum, the cylinder having an ac- commodating space with a first opening at the one end portion of the cylinder so that the accommodating space communicates with the fixing hole, wherein the first opening at the one end portion of the cylinder is smaller than a second opening at the other end portion of the cylinder, and wherein at least one guide rail is formed on the inner surface of the accommodating space for guiding the shaft to move in the longitudinal direction; a shaft installed movable in the accommodating space in the longitudinal direction so that the one end of the shaft can be protruded out of the cylinder or the one end of the shaft can be concealed into the accommodating space, the shaft having at least one protrusion portion for being interfered with the first opening, the protrusion portion formed on the outer surface of the shaft for being interfered with the guide rail wherein at least one rail groove for being engaged with the guide rail is formed at the interfering protrusion whereby the shaft can move in the longitudinal direction only when the rail groove is engaged with the guide rail; a back member fixed to the cylinder in which the shaft is located between the cylinder and the back member; and a spring installed between the back member and the shaft in a compressed condition; wherein the shaft can be rotated by the release of the engagement between the rail groove and the guide rail when the shaft is concealed in the accommodating space, and the one end of the shaft protruded to the outside of the edge of the drum is inserted into the fixing hole of the cartridge whereby the drum is rotatably supported.

Advantageous Effects

[37] As explained above, the present invention provides a device for installing a drum to a cartridge having at least one fixing hole for an image forming apparatus, comprising: a cylinder having at least one protrusion protruded on the outer surface at one end portion of the cylinder, wherein the protrusion interferes the edge of the drum so that the one end portion of the cylinder cannot be inserted into the inside of the drum while the other end portion of the cylinder can be inserted into the inside of the drum, and wherein an accommodating space is formed in the cylinder as having an opening toward the outside of the drum; a shaft installed movable in the accommodating space in the longitudinal direction so that the one end of the shaft can be protruded out of the opening or the one end of the shaft can be concealed into the accommodating space; and at least one elastic member for pushing the shaft so that the one end of the shaft be forced to be protruded out of the opening; wherein the one end of the shaft protruded to the outside of the edge of the drum is inserted into the fixing hole of the cartridge whereby the drum is rotatably supported, whereby the drum can be simply and easily installed to the cartridge without an excessive load applied to the drum during the installation, and further, the drum can be easily separated from the cartridge without any damages. [38] That is the present invention provides the device for installing the drum to be rotatably fixed to the cartridge only by using an elastic force or a relative interferences between components instead of permanent assembly method such as bonding, welding or tight fitting. [39] Further, the present invention provides the reliably improved quality of the each device because permanent assembly method depending on the skill of workers is fully excluded. [40] Also, the present invention realizes the reusability of all the components after the disassembly of the drum by preventing physical damages during the disassembly of the drum, and thus can reduce the cost of the drum change. [41] And, the present invention provides the device for installing or separating drum as a module thereby achieving the easy handling in addition to the reduction of the manufacturing cost. [42]

Brief Description of the Drawings [43] Accordingly, the present invention will be understood best through consideration of, and reference to, the following Figures, viewed in conjunction with the Detailed

Description of the Preferred Embodiment referring thereto, in which like reference numbers throughout the various Figures designate like structure and in which: [44] Fig. 1 is a side view of the conventional configuration of drum installed in a cartridge for an image forming apparatus. [45] Fig. 2 is a disassembled cross-sectional side view of the configuration of a drum installed in a cartridge for an image forming apparatus in accordance with the first embodiment of the present invention.

[46] Fig. 3 is a cross-sectional side view of the cylinder in Fig. 2.

[47] Fig. 4 is a perspective view of the shaft in Fig. 2.

[48] Fig. 5 is an assembled cross-sectional side view of Fig. 2.

[49] Fig. 6 is a disassembled cross-sectional side view of the configuration of a drum installed in a cartridge for an image forming apparatus in accordance with the second embodiment of the present invention.

[50] Fig. 7 is a perspective view of the first cylinder in Fig. 6.

[51] Fig. 8 is a perspective view of the second cylinder in Fig. 6.

[52] Fig. 9 is a perspective view of the shaft in Fig. 6.

[53] Figs. 10 to 12 are an assembled cross-sectional side view of the device in Fig. 6.

[54] Fig. 13 is a disassembled cross-sectional side view of the configuration of a drum installed in a cartridge for an image forming apparatus in accordance with the third embodiment of the present invention. [55] Fig. 14 is a perspective view of the cylinder in Fig. 13.

[56] Fig. 15 is a development view of the inner surface of the cylinder in Fig. 13.

[57] Fig. 16 is a perspective view of the shaft in Fig. 13.

[58] Figs. 17 is an assembled cross-sectional side view of the device in Fig. 13.

[59] Fig. 18 is a disassembled cross-sectional side view of the configuration of a drum installed in a cartridge for an image forming apparatus in accordance with the fourth embodiment of the present invention.

[60] Fig. 19 is a back view from A-A line in Fig. 18.

[61] Fig. 20 is a front view from B-B line in Fig. 18.

[62]

Best Mode for Carrying Out the Invention

[63] Hereinafter, the device for installing or separating a drum from a cartridge for an image forming apparatus in accordance with a first embodiment of the present invention will be explained in detail in conjunction with the accompanying drawings. In describing the present invention, detailed description of laid-out function or structure is omitted in order to clarify the gist of the present invention.

[64] As illustrated in Figs. 2 to 5, the device 100 for installing and separating a drum for a cartridge for an image forming apparatus in accordance with the first embodiment of the present invention comprises a cylinder 110 having a flange 112 protruded on the outer surface at one end 110a of the cylinder 110 wherein the flange 112 interferes the edge 10b of the drum 10 so that the one end 110a of the cylinder cannot be inserted into the inside of the drum 10 while the other end portion 110b of the cylinder can be inserted into the inside of the drum 10, a shaft 120 installed movable in the accommodating space 111 of the cylinder 110 in the longitudinal direction of the drum 10 so that the one end 120a of the shaft 120 can be protruded out of the opening or the one end 120a of the shaft 120 can be concealed into the accommodating space 111, a coil spring 130 for pushing the shaft 120 so that the one end 120a of the shaft 120 be forced to be protruded out of the opening, and a backing member 140 combined with the one other end 110b of the cylinder 110 with placing the shaft 120 between the shaft 120 and the backing member 140.

[65] As shown in Fig. 3, the cylinder 110 has the accommodating space 111 having its opening of which diameter dl is larger than the diameter d2 of the end 120a of the shaft 120 so that the one end 120a of the shaft 120 can be protruded through the opening with the shaft 120 being accommodated in the accommodating space 111. The flange 112 is protruded on the outer surface of the one end 110a of the cylinder 110 so that the flange 112 is interfered with the edge 10b of the drum 10. Further, in order that the shaft 120 is not protruded more than the predetermined length from the cylinder 110, a step 113 to be interfered by the shaft 120 is formed on the inner wall of the cylinder 120 when the end 120a of the shaft 120 is protruded by the predetermined length. At the other end 110b of the cylinder 110, a male screw 114 is formed to be engaged with the female screw 141 of the backing member 140. Also, in order that the shaft 120 can be maintained to be concealed in the accommodating space 111, a position fixing female screw 115 is formed on the inner wall of the cylinder 110 to be engaged with the position fixing male screw 123 of the shaft 120 when the end 120a of the shaft 120 is concealed in the accommodating space 111.

[66] The shaft 120 is accommodated in the accommodating space 111 of the cylinder

110, as shown in Fig. 2. In order to shorten the length of the total assembly, a spring accommodating groove 121 is formed on the bottom surface of the shaft 120 for accommodating the part of the coil spring 130. Further, a circumferential protrusion 122 is protruded on the outer surface of the shaft 120 so that the protrusion 122 is interfered with the step 113 of the cylinder 110 when the end 120a of the shaft is protruded by the predetermined length. Also, the position fixing male screw 123 is formed on the outer surface of the protrusion 122 which is engaged with the position fixing female screw 115 of the cylinder 110. In order to easily rotate the shaft 120 when the shaft 120 is accommodated in the accommodating space 111, "+" shaped groove 124 is formed on the end surface 120a of the shaft 120.

[67] The coil spring 130 is installed in the compressed condition between the shaft 120 and the backing member 140, thereby always exerting elastic force on the shaft 120 to be protruded from the cylinder 110.

[68] The device 100 comprised above makes the drum 10 to be rotatably supported in the cartridge by inserting the protruded end 120a of the shaft 120 to the fixing hole 2 of the cartridge 2'

[69] Hereinafter, the installation method using the device 100 in accordance with the first embodiment of the present invention is explained.

[70] Firstly, the shaft 120 is inserted into the accommodating space 111 of the cylinder

110. Herein, as the position fixing male screw 123 is engaged with the position fixing female screw 115 of the cylinder 110, the shaft 120 is required to be rotated to be accommodated into the accommodating space 111 of the cylinder 110.

[71] Thereafter, when the shaft 120 is inserted into the accommodating space 111 of the cylinder 110, with placing the coil spring 130 between the shaft 120 and the backing member 140, the male screw 114 of the cylinder is fastened with the female screw 141 of the backing member 140 whereby the coil spring 130 is compressed therebetween and the elastic force can be exerted to push the shaft 120.

[72] Thereafter, after the shaft 120 is concealed within the cylinder 110 by slightly pushing the shaft 120, the shaft 120 is rotated driven by a screwdriver so that the position fixing female screw 114 of the cylinder 110 is engaged with the position fixing male screw 123 of the shaft 120, thereby stably maintaining the concealed state of the shaft 120 in spite of the compressed coil spring 130. Herein, the shaft 120 is driven with the screwdriver by engaging the end of the screwdriver with the "+" shaped groove 124.

[73] Then, a module comprising the cylinder 110, the shaft 120, the coil spring 130 and the backing member 140 is inserted to the inside 10a (i.e., hollow inner space) of the one end of the drum 10. As the flange 113 is formed protruded on the outer surface of the one end 110a of the cylinder 110, the other end 110b of the cylinder 110 can be inserted into the inside 10a of the drum 10 while the one end 110a having the flange 113 of the cylinder 110 cannot be inserted into the inside 10a of the drum 10.

[74] Thereafter, after the other end of the drum 10 having a driving gear is connected with the driving part of the cartridge 2' the drum 10 is aligned with the fixing hole 2 of the cartridge 2' Then, a screwdriver having "+" shaped end is inserted through the fixing hole 2 so as to put the end of the screwdriver into the "+" shaped groove 124, and the fastened state between the position fixing female screw 123 of the cylinder 110 and the position fixing male screw 114 of the shaft is released by rotating the screwdriver. Therefore, the end 120a of the shaft 120 is protruded from the outside of the drum 10 by the elastic force of the compressed coil spring 130 whereby the protruded shaft is inserted into the fixing hole 2 of the cartridge and thus the drum 10 can be rotatably supported to the cartridge.

[75] Hereinafter, the separation method using the device 100 in accordance with the first embodiment of the present invention is explained.

[76] Firstly, in order that the end 120a of the shaft 120 is got away from the fixing hole 2 of the cartridge 2' after the end of the screwdriver is put to the "+" shaped groove 124, the shaft 120 is pressurized via the screwdriver from an operator. When the end 120a of the shaft 120 is concealed in the accommodating space 111, the shaft 120 is rotated using the screwdriver whereby the position fixing male screw 123 of the shaft 120 is engaged with the position fixing female screw 115.

[77] At this time, as there is not any interferences between the drum 10 and the fixing hole 2 of the cartridge 2' without the troublesome process such as a cutting of a drum 10, the drum 10 can be easily and simply separated from the cartridge 2'

[78] That is, when the drum 10 is separated from the cartridge 2' like this, the module comprising the cylinder 110, the shaft 120, the coil spring 130 and the backing member 140 maintains its shape as it was. Besides, as the drum 10 is installed to the cartridge 2' with excluding permanent assembly methods, all the components 110-140 can be reused even after the change of the drum 10. Also, in case that only one component thereof is required to be changed, as the drum 10 is separated from the cartridge 2' as above method, the other components including the drum 10 can be reused without causing any problem.

[79] That is, as the device 100 of the first embodiment of the present invention only uses the re-combinable attaching method such as fitting or elastic force of the coil spring, the process of installing the drum 10 to the cartridge 2' or the process of separating the drum 10 from the cartridge 2' is very simplified. Further, as the device 100 includes the position fixing screws 115, 123 for maintaining the concealed state of the screw 120, it is much easier and more convenient for an operator or a user to install or separate the drum 10 from the cartridge 2' Mode for the Invention

[80] Hereinafter, the device 200 in accordance with a second embodiment of the present invention is explained.

[81] As illustrated in the Figs. 6 to 12, the device 200 for installing and separating a drum for a cartridge for an image forming apparatus in accordance with the second embodiment of the present invention comprises a first cylinder 220 having a flange 224 protruded on the outer surface at one end of the first cylinder 220 wherein the flange 224 interferes the edge 10b of the drum 10, a second cylinder 210 combined with the first cylinder 220, and a shaft 120 installed movable in the accommodating space 211 of the second cylinder 210 in the longitudinal direction of the drum 10.

[82] As shown in Figs. 6 and 7, the first cylinder 220 is formed as a hollow pipe to have a longitudinally penetrated inner space 221 in its center. And the flange 224 is protruded formed on the outer surface at one (i.e., top) end thereof, and a locking groove 222 is formed in the circumferential direction on the bottom surface. Also, several combination protrusions 223 are formed on the bottom surface of the first cylinder 220 so that the guide groove 212 and the locking groove 222 are connected with each other when the first cylinder 220 is combined with the second cylinder 210.

[83] As shown in Fig. 8, four guide grooves 212 are formed on the inner wall of the second cylinder 210 to guide the shaft 230 in the longitudinal direction. Herein, in order to prevent the shaft 230 from being fallen into the deep inside of the drum 10, closed ends 212a are formed at the end of the each guide groove 212. Also, the combination groove 213 to accommodate the combination protrusion 223 are formed on the end (i.e., top) surface of the second cylinder 210.

[84] As shown in Fig. 9, the guide projections 231 are protruded formed at intervals of

90 degrees on the outer surface of the shaft 230, which is to be inserted to the guide grooves 212 respectively so as to guide the shaft 230 in the longitudinal direction, and thus, the end of the shaft 230 is protruded from the first cylinder 220 or is concealed in the second cylinder 210. Herein, the movement of the shaft 230 is realized by hooking the grip bar 232 formed to connect the inner wall of the shaft 230 and then by pulling or pushing the grip bar 232 with a suitable tool such as pliers or pincers.

[85] Similarly, the device 200 comprised above makes the drum 10 to be rotatably supported in the cartridge 2' by inserting the end of the shaft 230 protruded to the outside of the drum 10 into the fixing hole 2 of the cartridge 2'

[86] Also, by separately manufacturing the first cylinder 220 and the second cylinder

210, the cylinders 210, 220 can be promptly and cheaply manufactured such by an injection molding method.

[87] Hereinafter, the installation method using the device 200 in accordance with the second embodiment of the present invention is explained.

[88] Firstly, after the shaft 230 is aligned with the second cylinder 210 so that the guide projections 231 of the shaft 230 can be inserted into the guide grooves 212, the shaft 230 is inserted into the accommodating space 211 of the second cylinder 210.

[89] Thereafter, as shown in Fig. 11, the combination protrusions 223 of the first cylinder 220 is inserted to the combination groove 213, and if necessary, the facing surface thereof are bonded to each other. Although the first cylinder 220 and the second cylinder 210 is bonded to each other, as the cylinders 210, 220 are not bonded to the drum 10, it does not cause any trouble such as a drum cutting in the separation process of the drum 10 from the cartridge 2' From this, the shaft 230 can be installed movable within the accommodating space 211 and cannot be sneaked away from the accommodating space 211.

[90] Thereafter, a module comprising the cylinders 210, 220 and the shaft 230is inserted to the inside 10a (i.e., hollow inner space) of the one end of the drum 10. As the flange 224 is formed protruded on the outer surface of the one end of the first cylinder 120, the module is inserted into the inside of the drum 10 with the flange 224 hanging on the edge 10a of the drum 10.

[91] Thereafter, after the other end of the drum 10 having a driving gear is connected with the driving part of the cartridge 2' the drum 10 is aligned with the fixing hole 2 of the cartridge 2' Then, the grip bar 232 is gripped by a suitable tool through the fixing hole and then pulled whereby the shaft 230 can be protruded from the first cylinder 220. As shown in Fig. 12, when the guide projections 231 reach the end of the guide grooves 212, the one end of the shaft 230 is protruded through the first cylinder 220 by the predetermined length. Herein, the protruded shaft 230 is inserted into the fixing hole 2 of the cartridge 2' thereby rotatably supporting the drum 10 in the cartridge 2'

[92] Thereafter, in order to prevent the shaft 230 from being sneaked away from the fixing hole (i.e., the shaft 230 is concealed into the second cylinder 210) by any external impact, the shaft 230 is rotated by the suitable tool and thus the guide projections 231 reaches the end of the locking grooves 222 from the guide grooves 212.

[93] Although not shown in the accompanying figures, in order to achieve firm fixation of the shaft 230, extending grooves may be further extended from the each of the locking grooves 222, of which path is bent from the locking grooves 222. Therefore, the extending grooves may have more than one additional bent point. Further, at least one path of the extending grooves is desirable to be formed in the circumferential direction.

[94] From these constructions, as the shaft 230 will not be sneaked away from the fixing hole 2 of the cartridge 2' in spite of the external vibration or impact, the one end of the drum 10 can be stably rotatably supported.

[95] Hereinafter, the separation method using the device 200 in accordance with the second embodiment of the present invention is explained.

[96] Firstly, in order that the end of the shaft 230 is got away from the fixing hole 2 of the cartridge 2' after the grip bar 232 is gripped by a suitable tool through the fixing hole 2, an operator or a user rotates the shaft 230 with the tool so that the guide projections 231 of the shaft 230 reach the guide grooves 212 from the locking grooves 222.

[97] Thereafter, when an operator or a user pushes the shaft 230 with the tool, the end of the shaft 230 becomes concealed in the first cylinder 220. At this time, as there is not any interference between the drum 10 and the fixing hole 2 of the cartridge 2' without any troublesome process such as drum cutting, the drum 10 can be separated from the cartridge 2'

[98] Similarly to the first embodiment, after the module comprising the first cylinder

220, the second cylinder 210 and the shaft 230 is separated from the drum, each of the components 210-230 maintains its shape as it was. Besides, as the drum 10 is installed to the cartridge 2' with excluding permanent assembly methods, all the components 210-230 can be reused even after the change of the drum 10. Also, in case that only one component thereof is required to be changed, as the drum 10 is separated from the cartridge 2' as above method, the other components including the drum 10 can be reused without causing any problem.

[99]

[100] Hereinafter, the device 300 in accordance with a third embodiment of the present invention is explained.

[101] As illustrated in the Figs. 13 to 17, the device 300 for installing and separating a drum for a cartridge for an image forming apparatus in accordance with the third embodiment of the present invention is characterized in that the cylinder is formed as one body instead of separate two bodies in the second embodiment.

[102] Concretely, the device 300 comprises a cylinder 310 having an inner space as an ac- commodating space 311 in which guide grooves 312 are formed in the longitudinal direction, a shaft 320 installed movable in the accommodating space 311 in the longitudinal direction by being guided along the guide grooves 312.

[103] As shown in Fig. 14, the flange 313 is protruded on the outer surface at one end of the cylinder 310 so that the flange 313 is interfered with the edge 10b of the drum 10.

[104] Herein, as shown in Fig. 15, although the guide grooves 312 are formed along the longitudinal direction on the inner wall of the cylinder 310, in order to prevent that the shaft 320 protruded by the predetermined length becomes concealed into the cylinder 310 by any external impacts, the end portion of the guide grooves 312 is bent at least one point, and extending grooves 312b are formed extended from the end of the guide grooves 312. Herein, each of the extending grooves 312b includes a path in the circumferential direction. Also, a locking portion 312c of which width is shorter than that of other portion is formed at inlet portion of each of the guide grooves 312. Thus, once the guide projection 321 passes through the locking portion 312c of the guide groove 312 by a slight intentional impact when the shaft 320 is inserted to the accommodating space 311, the guide projection 321 of the shaft 320 is prevented from being sneaked from the cylinder 310 at least by the weight of the shaft.

[105] As shown in Fig. 16, the guide projections 321 are protruded formed at intervals of

90 degrees on the outer surface of the shaft 320, which is to be inserted to the guide grooves 312 respectively so as to guide the shaft 320 in the longitudinal direction, and thus, the end of the shaft 320 is protruded from the cylinder 310 or is concealed in the cylinder 310. Herein, the movement of the shaft 320 is realized by gripping the grip bar 322 and then by pulling or pushing the grip bar 322 with a suitable tool such as pliers or pincers.

[106] Similarly, the device 300 comprised above makes the drum 10 to be rotatably supported in the cartridge 2' by inserting the end of the shaft 320 protruded to the outside of the drum 10 into the fixing hole 2 of the cartridge 2'

[107] Hereinafter, the installation method using the device 300 in accordance with the third embodiment of the present invention is explained.

[108] Firstly, after the shaft 320 is aligned with the cylinder 310 so that the guide projections 321 of the shaft 320 can be inserted into the guide grooves 312, the shaft 320 is inserted into the accommodating space 311 of the cylinder 310.

[109] Thereafter, the assembly of the cylinder 310 and the shaft 320 is inserted into the inside 10a of the drum 10. Herein, as the flange 313 is protruded on the outer surface of the cylinder 310 to be interfered with the edge 10b of the drum 10, the cylinder 310 is inserted into the inside 10a of the drum except the flange 313.

[110] Then, after the other end of the drum 10 having a driving gear is connected with the driving part of the cartridge 2' the drum 10 is aligned with the fixing hole 2 of the cartridge 2' Then, the grip bar 322 is gripped by a suitable tool through the fixing hole 2 and then pulled whereby the shaft 320 can be protruded from the cylinder 310. As shown in Fig. 17, when each of the guide projections 321 reaches the end of the each guide groove 312, the one end of the shaft 320 is protruded through the cylinder 310 by the predetermined length. Herein, the protruded shaft 320 is inserted into the fixing hole 2 of the cartridge 2' thereby rotatably supporting the drum 10 in the cartridge 2'

[111] Thereafter, in order to prevent the shaft 320 from being sneaked away from the fixing hole (i.e., the shaft 320 is concealed into the second cylinder 210) by any external impact, the shaft 320 is rotated by the suitable tool and thus each of the guide projections 321 reaches the end of the extending groove 312b from the guide grooves 312.

[112] From these constructions, as the shaft 320 will not be sneaked away from the fixing hole 2 of the cartridge 2' in spite of the external vibration or impact, the one end of the drum 10 can be stably rotatably supported.

[113] Hereinafter, the separation method using the device 300 in accordance with the third embodiment of the present invention is explained.

[114] Firstly, in order that the end of the shaft 320 is got away from the fixing hole 2 of the cartridge 2' after the grip bar 322 is gripped by a suitable tool through the fixing hole 2, an operator or a user rotates the shaft 320 with the tool so that the guide projections 321 of the shaft 320 reach the guide grooves 312 from the extending grooves 312b.

[115] Thereafter, when an operator or a user pushes the shaft 320 with the tool, the end of the shaft 320 becomes concealed in the cylinder 310. At this time, as there is not any interference between the drum 10 and the fixing hole 2 of the cartridge 2' without any troublesome process such as drum cutting, the drum 10 can be separated from the cartridge 2'

[116] Similarly to the embodiments described above, after the module comprising the cylinder 310 and the shaft 320 is separated from the drum 10, each of the components 310, 320 maintains its shape as it was. Besides, as the drum 10 is installed to the cartridge 2' with excluding permanent assembly methods, all the components 310, 320 can be reused even after the change of the drum 10. Also, in case that only one component thereof is required to be changed, as the drum 10 is separated from the cartridge 2' as above method, the other components including the drum 10 can be reused without causing any problem.

[117]

[118] Hereinafter, the device 400 in accordance with a fourth embodiment of the present invention is explained.

[119] As illustrated in the Figs. 18 to 20, the device 400 for installing and separating a drum for a cartridge for an image forming apparatus in accordance with the fourth embodiment of the present invention comprises a cylinder 410 having a flange 412 protruded on the outer surface at one end of the cylinder 410 wherein the flange 412 interferes the edge 10b of the drum 10 so that the one end of the cylinder cannot be inserted into the inside of the drum 10 while the other portion except the flange 412 of the cylinder can be inserted into the inside 10a of the drum 10, a shaft 420 installed movable in the accommodating space 411 of the cylinder 410 in the longitudinal direction of the drum 10 along the guide rails 415 on the inner wall of the accommodating space 411 so that the one end of the shaft 420 can be protruded out of the opening or the one end of the shaft 420 can be concealed into the accommodating space 411, a coil spring 430 for pushing the shaft 420 so that the one end of the shaft 420 be forced to be protruded out of the opening, and a backing member 440 combined with the one other end of the cylinder 410 with placing the shaft 420 between the shaft 420 and the backing member 440.

[120] As shown in Fig. 18, the cylinder 410 has the accommodating space 411 having its opening of which diameter is larger than the diameter of the end of the shaft 420 so that the one end of the shaft 420 can be protruded through the opening. The flange 412 is protruded on the outer surface of the one end of the cylinder 410 so that the flange 412 is interfered with the edge 10b of the drum 10. Further, in order that the shaft 420 is not protruded more than the predetermined length from the cylinder 410, a step 413 to be interfered by the shaft 420 is formed on the inner wall of the cylinder 420 when the end of the shaft 420 is protruded by the predetermined length. At the other end of the cylinder 410, male screw 414 is formed to be engaged with the female screw 441 of the backing member 440. Also, in order that the shaft 420 can be maintained to be concealed in the accommodating space 411, as shown in Fig. 18, guide rails 415 are formed in the longitudinal direction from the step 413 not to the other end of the cylinder 410.

[121] The shaft 420 is accommodated in the accommodating space 411 of the cylinder

410, as shown in Fig. 18. In order to shorten the length of the total assembly, spring accommodating groove 421 is formed on the bottom surface of the shaft 420 for accommodating the part of the coil spring 430. Further, circumferential protrusion 422 is protruded on the outer surface of the shaft 420 so that the protrusion 422 is interfered with the step 413 of the cylinder 410 when the end of the shaft is protruded by the predetermined length. Also, on the outer surface of the protrusion 422, rail grooves 423 are formed at positions where the guide rails 415 are located thereby allowing the shaft 420 to slide along the guide rail 415 in the accommodating space 411. In order to easily rotate the shaft 420 when the shaft 420 is accommodated in the accommodating space 411, "+" shaped groove 424 is formed on the end surface of the shaft 420. [122] The coil spring 430 is installed in the compressed condition between the shaft 420 and the backing member 440, thereby always exerting elastic force on the shaft 420 to be protruded from the cylinder 410.

[123] That is, compared with the device 100, the device 400 in accordance with the fourth embodiment is characterized in that the guide rails 415 are formed in the longitudinal direction in the accommodating space 411, and the shaft 420 slides longitudinally along the guide rail 415 with the rail grooves 423 of the shaft 420 engaged with the guide rails 415.

[124] More concretely, as shown in Fig. 18, the guide rails 415 in the cylinder 410 does not extend to the end of the cylinder 410 so that the rail grooves 423 which reached the immersing portion 411a can be derailed from the guide rails 415 thereby allowing the rotation of the shaft 420 when the shaft 420 reaches to be fully concealed in the cylinder 410. Therefore, when the shaft 420 is being protruded or is protruded from the cylinder 410, the shaft 420 tends to be protruded by the elastic force of the coil spring 430. However, when the shaft 420 is concealed in the cylinder 410, due to the interferences between the protrusion 422 and the end of the guide rails 415, the shaft 420 tends to be more locked as being concealed by the elastic force of the coil spring 430.

[125] The device 400 comprised above makes the drum 10 to be rotatably supported in the cartridge by inserting the protruded end of the shaft 420 to the fixing hole 2 of the cartridge 2' Also, the device 400 has an advantageous effect of improved productivity compared with the device 100 by excluding the screw assembly structure which requires the lots of time to assemble and to manufacture.

[126] Herein, in order to be capable of rotating of the shaft 420 when the shaft 420 is concealed in the cylinder 410, the height of the guide rails 415 is determined.

[127] Hereinafter, the installation method using the device 400 in accordance with the fourth embodiment of the present invention is explained.

[128] Firstly, the shaft 420 is inserted into the accommodating space 411 of the cylinder

410, so that the rail grooves 423 are engaged with the guide rails 415 in the cylinder 410.

[129] Thereafter, when the shaft 420 is inserted into the accommodating space 411 of the cylinder 410, with placing the coil spring 430 between the shaft 420 and the backing member 440, the male screw 414 of the cylinder is fastened with the female screw 441 of the backing member 440 whereby the coil spring 430 is compressed therebetween and the elastic force can be exerted to push the shaft 420.

[130] Thereafter, after the shaft 420 is concealed within the cylinder 410 by slightly pushing the shaft 420, the shaft 420 is rotated driven by a screwdriver so that the rail grooves 423 of the shaft 420 located at the immersing portion 411a can be derailed from the guide rails 415 in the cylinder 410, thereby stably maintaining the concealed state of the shaft 420 in spite of the compressed coil spring 430. Herein, the shaft 420 is driven to rotate with the screwdriver by putting the end of the screwdriver with the "+" shaped groove 424.

[131] Then, a module comprising the cylinder 410, the shaft 420, the coil spring 430 and the backing member 440 is inserted to the inside 10a of the one end of the drum 10. As the flange 413 is formed protruded on the outer surface of the one end of the cylinder 410, the other portion except the flange 413 of the cylinder 410 is inserted into the inside 10a of the drum 10.

[132] Thereafter, after the other end of the drum 10 having a driving gear is connected with the driving part of the cartridge 2' the drum 10 is aligned with the fixing hole 2 of the cartridge 2' Then, a screwdriver having "+" shaped end is inserted through the fixing hole 2 so as to put the end of the screwdriver into the "+" shaped groove 424, and the shaft 420 is rotated by the screwdriver so that the rail grooves 423 of the shaft 420 are engaged with the guide rails 415 in the cylinder 410. Therefore, the end of the shaft 420 is protruded from the outside of the drum 10 by the elastic force of the compressed coil spring 430 whereby the protruded shaft is inserted into the fixing hole 2 of the cartridge and thus the drum 10 can be rotatably supported to the cartridge.

[133] Hereinafter, the separation method using the device 400 in accordance with the fourth embodiment of the present invention is explained.

[134] Firstly, in order that the end of the shaft 420 is got away from the fixing hole 2 of the cartridge 2' after the end of the screwdriver is put to the "+" shaped groove 424, the shaft 420 is pressurized via the screwdriver from an operator. When the end of the shaft 420 is concealed in the accommodating space 411, the shaft 420 is rotated using the screwdriver whereby the rail grooves 423 located at the immersing portion 41 Ia is derailed from the guide rails 415, and the protrusion 422 of the shaft 420 becomes interfered with the end surface of the guide rails 415. From these operations, the shaft 420 can be stably maintained to be concealed in the cylinder 410. Further, as the elastic force of the coil spring 430 urges the protrusion 422 to compulsorily face the end of the guide rails 415, as long as the rail grooves 423 can be compulsorily engaged with the guide rails 415 by an operator or a user, the concealed state of the shaft 420 can be firmly maintained.

[135] At this time, as there is not any interferences between the drum 10 and the fixing hole 2 of the cartridge 2' without the troublesome process such as a cutting of a drum, the drum 10 can be easily and simply separated from the cartridge 2'

[136] That is, when the drum 10 is separated from the cartridge 2' like there operations, the module comprising the cylinder 410, the shaft 420, the coil spring 430 and the backing member 440 maintains its shape as it was. Besides, as the drum 10 is installed to the cartridge 2' with excluding permanent assembly methods, all the components 410-440 can be reused even after the change of the drum 10. Also, in case that only one component thereof is required to be changed, as the drum 10 is separated from the cartridge 2' as above method, the other components including the drum 10 can be reused without causing any problem. Industrial Applicability

[137] As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalence of such metes and bounds are therefore intended to be embraced by the appended claims.

[138]

[139]

Claims

[1] A device for installing a drum to a cartridge having at least one fixing hole for an image forming apparatus, comprising: a cylinder having at least one protrusion protruded on the outer surface at one end portion of the cylinder, wherein the protrusion interferes the edge of the drum so that the one end portion of the cylinder cannot be inserted into the inside of the drum while the other end portion of the cylinder can be inserted into the inside of the drum, and wherein an accommodating space is formed in the cylinder as having an opening toward the outside of the drum; a shaft installed movable in the accommodating space in the longitudinal direction so that the one end of the shaft can be protruded out of the opening or the one end of the shaft can be concealed into the accommodating space; and at least one elastic member for pushing the shaft so that the one end of the shaft be forced to be protruded out of the opening; wherein the one end of the shaft protruded to the outside of the edge of the drum is inserted into the fixing hole of the cartridge whereby the drum is rotatably supported.

[2] The device as claimed in claim 1, wherein at least one interference part is formed at at least one of the shaft and the cylinder where the one end of the shaft is protruded by a predetermined length

[3] The device as claimed in claim 2, wherein a pair of screws engaged with each other for fixing the relative position between the shaft and the cylinder are formed, the pair of screws being formed as male screw on the outer surface of the shaft and being formed as female screw on the inner surface of cylinder at a position where the one end of the shaft is protruded by the predetermined length.

[4] The device as claimed one of claims 1 to 3, wherein a pair of screws engaged with each other for fixing the relative position between the shaft and the cylinder, the pair of screws being formed as male screw on the outer surface of the shaft and being formed as female screw on the inner surface of cylinder at a position where the one end of the shaft is concealed into the accommodating space.

[5] The device as claimed in claim 4, wherein "+" shaped groove or "-" shaped groove is formed on the one end surface of the shaft so that the shaft can be rotated by a screwdriver.

[6] A device for installing a drum to a cartridge having at least one fixing hole for an image forming apparatus, comprising: a cylinder having a flange protruded on the outer surface at one end portion of the cylinder, wherein the flange interferes the edge of the drum so that the one end portion of the cylinder cannot be inserted into the inside of the drum while the other end portion of the cylinder can be inserted into the inside of the drum, the cylinder being formed as having an accommodating space penetrating the cylinder in the longitudinal direction and having a step on the inner wall of the accommodating space; a shaft installed movable in the accommodating space in the longitudinal direction so that the one end of the shaft can be protruded out of the outside opening or the one end of the shaft can be concealed into the accommodating space, the shaft having at least one protrusion protruded on the outer surface so that the protrusion is interfered with the step for limiting the movement of the shaft, wherein at least one groove is formed on the one end surface of the shaft so that the groove is engaged with a screwdriver; a back member fixed at the inner opening of the cylinder so that the shaft in the accommodating space cannot be out of the accommodating space; and at least one elastic member located between the shaft and the back member for pushing the shaft to the outside of the drum so that the one end of the shaft be forced to be protruded out of the outside opening; wherein the one end of the shaft protruded to the outside of the edge of the drum is inserted into the fixing hole of the cartridge whereby the drum is rotatably supported.

[7] A device for installing a drum to a cartridge having at least one fixing hole for an image forming apparatus, comprising: a shaft having at least one guide projection protruded on the outer wall and having at least one grip portion to be caught from the one end of the shaft; a first cylinder having at least one protrusion on the outer surface at one end portion of the first cylinder, wherein the protrusion interferes the edge of the drum so that one end portion of the first cylinder cannot be inserted into the inside of the drum while the other end portion of the first cylinder can be inserted into the inside of the drum, the first cylinder being formed as a hollow pipe so that the fixing hole communicates with the inside of the first cylinder, wherein at least one locking groove is formed in the circumferential direction at the other end portion of the first cylinder so that the protrusion can be inserted; a second cylinder being located in the inside of the drum by being combined with the other end portion of the first cylinder, the second cylinder having accommodating space for accommodating the shaft wherein at least one guide groove is formed on the inner surface of the second cylinder so that the at least one guide projection of the shaft is inserted the guide groove to guide the shaft movable in the accommodating space in the longitudinal direction whereby the one end of the shaft can be protruded out of the first cylinder or the one end of the shaft can be concealed into the accommodating space; wherein the guide groove and the locking groove are connected with each other when the first cylinder and the second cylinder are combined with each other so that the guide projection can move between the guide groove and the locking groove, and wherein the one end of the shaft protruded to the outside of the edge of the drum is inserted into the fixing hole of the cartridge whereby the drum is rotatably supported.

[8] The device as claimed in claim 7, wherein the shaft has an inside and the grip portion is formed as a bar to be connected with the inner wall of the shaft.

[9] The device as claimed in claim 7, wherein at least one extending groove is formed on the inner wall of the first cylinder as at least one bent path from the locking groove.

[10] The device as claimed in claim 9, wherein the extending groove is formed bent at least one point and at least one portion of the extending groove is formed in the circumferential direction.

[11] The device as claimed one of claims 7 to 10, wherein at least one engaging portion is formed at least one of the first cylinder and the second cylinder so that the guide groove and the extending groove is connected to each other when the first cylinder and the second cylinder are combined each other.

[12] A device for installing a drum to a cartridge having at least one fixing hole for an image forming apparatus, comprising: a shaft having at least one guide projection protruded on the outer wall and having at least one grip portion to be caught from the one end of the shaft; and a cylinder having at least one protruded interfering portion on the outer surface at one end portion, wherein the interfering portion interferes the edge of the drum so that one end portion of the first cylinder cannot be inserted into the inside of the drum while the other end portion of the first cylinder can be inserted into the inside of the drum, the cylinder having an accommodating space for accommodating the shaft, wherein at least one guide groove is formed on the inner surface of the cylinder so that the at least one guide projection of the shaft is inserted the guide groove to guide the shaft movable in the accommodating space in the longitudinal direction whereby the one end of the shaft can be protruded out of the cylinder or the one end of the shaft can be concealed into the accommodating space; wherein the one end of the shaft protruded to the outside of the edge of the drum is inserted into the fixing hole of the cartridge whereby the drum is rotatably supported.

[13] A device for installing a drum to a cartridge having at least one fixing hole for an image forming apparatus, comprising: a cylinder having at least one protrusion on the outer surface at one end portion so that the protrusion is interfered with the edge of the drum whereby the other end portion of the cylinder is inserted into the inside of the drum while the one end portion of the cylinder is not inserted into the inside of the drum, the cylinder having an accommodating space with an opening at the one end portion of the cylinder so that the accommodating space communicates with the fixing hole, wherein at least one guide rail is formed on the inner surface of the accommodating space for guiding the shaft to move in the longitudinal direction; a shaft installed movable in the accommodating space in the longitudinal direction so that the one end of the shaft can be protruded out of the cylinder or the one end of the shaft can be concealed into the accommodating space, the shaft having at least one interfering protrusion formed on the outer surface of the shaft for being interfered with the guide rail wherein at least one rail groove for accommodating the guide rail is formed at the interfering protrusion whereby the shaft can move in the longitudinal direction only when the rail groove is engaged with the guide rail; and an elastic member for exerting elastic force on the shaft so that the shaft is protruded out of the cylinder; wherein the shaft can be rotated by the release of the engagement between the rail groove and the guide rail when the shaft is concealed in the accommodating space, and the one end of the shaft protruded to the outside of the edge of the drum is inserted into the fixing hole of the cartridge whereby the drum is rotatably supported.

[14] A device for installing a drum to a cartridge having at least one fixing hole for an image forming apparatus, comprising: a cylinder having a flange on the outer surface at one end portion so that the protrusion is interfered with the edge of the drum whereby the other end portion of the cylinder is inserted into the inside of the drum while the one end portion of the cylinder is not inserted into the inside of the drum, the cylinder having an accommodating space with a first opening at the one end portion of the cylinder so that the accommodating space communicates with the fixing hole, wherein the first opening at the one end portion of the cylinder is smaller than a second opening at the other end portion of the cylinder, and wherein at least one guide rail is formed on the inner surface of the accommodating space for guiding the shaft to move in the longitudinal direction; a shaft installed movable in the accommodating space in the longitudinal direction so that the one end of the shaft can be protruded out of the cylinder or the one end of the shaft can be concealed into the accommodating space, the shaft having at least one protrusion portion for being interfered with the first opening, the protrusion portion formed on the outer surface of the shaft for being interfered with the guide rail wherein at least one rail groove for being engaged with the guide rail is formed at the interfering protrusion whereby the shaft can move in the longitudinal direction only when the rail groove is engaged with the guide rail; a back member fixed to the cylinder in which the shaft is located between the cylinder and the back member; and a spring installed between the back member and the shaft in a compressed condition; wherein the shaft can be rotated by the release of the engagement between the rail groove and the guide rail when the shaft is concealed in the accommodating space, and the one end of the shaft protruded to the outside of the edge of the drum is inserted into the fixing hole of the cartridge whereby the drum is rotatably supported.