KR100608015B1 - Electrophotographic image forming apparatus where a transfer unit is installed and uninstalled by means of closing and opening the door device - Google Patents

Abstract

Disclosed is an image forming apparatus in which a transfer unit is detached by opening and closing a door member. An image forming apparatus according to the present invention includes a transfer unit, a door member rotatably installed in an image forming apparatus main body, a transfer unit coupling means for coupling / separating a door member and a transfer unit, and a transfer unit coupled to the door member. Positioning means for mounting the apparatus at a predetermined position of the main body of the image forming apparatus, and pressurizing means for pressing the transfer unit mounted on the main body in the direction of the photosensitive member. By such a configuration, the transfer unit can be easily attached / detached to the main body, and the transfer unit can be pressed in the direction of the photosensitive member based on the rotation center point assembled at the correct position.

Transfer unit, Door member, Transfer unit coupling means, Positioning means, Pressing means

Description

Electrophotographic image forming apparatus where a transfer unit is installed and uninstalled by means of closing and opening the door device}

1 is a schematic cross-sectional view of an image forming apparatus according to the present invention.

Figure 2 is a perspective view showing the main part of the transfer unit and the door member of the present invention.

Figure 3 is a side cross-sectional view showing a state in which the transfer unit of the present invention is coupled to the door member.

Figure 4 is a side cross-sectional view showing a process of mounting the door member of the present invention to the image forming apparatus main body.

Figure 5 is a side cross-sectional view showing a state in which the transfer unit of the present invention is mounted on the image forming apparatus main body.

Figure 6 is a perspective view of the main part of the locking means according to an embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

1 ... Develop cartridge frame 10 (10C, 10M, 10Y, 10K) ... Develop cartridge

11 ... photosensitive member 12 ... developing roller

13 ... Daejeon Roller 14 ... Supply Roller

16.Toner layer restriction member 17 ...

20 ... Transfer belt 21,22,23,24 ... support roller

30 (30C, 30M, 30Y, 30K) ... Exposure part 40 ... Transfer roller

50 ... Fitting part 51 ... Heating roller

52 ... Pressure Roller 60 ... Printing Unit

70 ... cassette 72 ... pick-up roller

74 Feed rollers 76 Discharge rollers

99.Image Body 100.Transfer Unit

110 ... engaging projection 111 ...

112.Small diameter part 120.Pressure surface

130 Hook hook groove 140 Positioning projection

150 handle 200 door member

201 ... door member hinge 210 ... Joining boss

220 Pressing means 230 Hook part

231 Hook connecting shaft 232 Lever

240 ... Locker 990 ... Guide rail

991 ... Elastic stopper 992 ... Positioning part

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus, and more particularly, to an image forming apparatus which can easily attach and detach a transfer unit to a predetermined position of an image forming apparatus main body.

The image forming apparatus refers to a device that receives a digital signal input such as a character or an image and outputs a visible image to a recording medium such as paper, such as a printer, a digital copier, a scanner, a facsimile or the like. Among them, the electrophotographic image forming apparatus is an apparatus for printing an image on paper or the like by an electrophotographic process. The electrophotographic image forming apparatus includes a charger, a photosensitive member, an exposure unit, a developing unit, a transfer unit, a fixing unit, a paper feeding unit, and the like. Each unit sequentially performs charging, exposure, photosensitive, developing, transfer, and fixing processes to form an image on the paper.

Since a plurality of units are provided in the color image forming apparatus, the installation structure is complicated and the installation area is increased. Since the installation structure is complicated, the arrangement of each unit is difficult. The ease of replacing consumable units must also be considered in the design of the layout of each unit. In particular, when the paper jam is removed, the transfer path of the paper needs to be exposed, so that the transfer unit in contact with the paper is frequently separated from the image forming apparatus. If the separated transfer unit is dropped on the floor, the transfer unit may be damaged. If the mounting / detaching method of the transfer unit is complicated, there is a fear that other parts of the image forming apparatus may be damaged while separating the transfer unit by disregarding it. Therefore, there is a need for mounting / dismounting means of the transfer unit that is simple and does not cause damage to the device.

For correct operation of the transfer unit, a plurality of transfer rollers must maintain a predetermined assembly tolerance with each opposing photosensitive member, and maintain an appropriate contact pressure necessary for transfer. Therefore, when assembling the transfer unit at a predetermined position of the main body of the image forming apparatus, there is a need for a mounting positioning means capable of maintaining an accurate assembly tolerance regardless of a separate assembly jig or an operator's skill. In addition, it is necessary to press the pressure means for pressing the transfer roller to each photosensitive member with an appropriate force.

SUMMARY OF THE INVENTION The present invention is to improve the above-mentioned problems, it is simple but can be mounted / detached transfer unit without fear of damage to the image forming apparatus, the assembly tolerance and the pressing force of the transfer unit, regardless of the separate assembly jig or operator's skill It is an object of the present invention to provide an image forming apparatus capable of maintaining a high temperature.

In order to achieve the above object, the image forming apparatus according to the present invention,

An image forming apparatus main body having a photosensitive member on which a toner image is developed;

A door member rotatably installed on the main body to open and close a part of the main body;

A transfer unit coupled to the door member and transferring the toner image onto paper;

Transfer unit coupling means for coupling the transfer unit and the door member;

Pressing means for pressing the transfer unit coupled to the door member in the direction of a photosensitive member; The transfer unit is pressed in the direction of the photosensitive member when the door member is closed, and is separated from the main body when the door member is opened.

Transfer unit coupling means, the coupling projection is provided in the transfer unit, including a large diameter portion having a large diameter and a small diameter portion having a small diameter; A coupling boss provided in the door member to rotatably support the coupling protrusion and having an opening through which the small diameter portion passes when the door member and the transfer unit are coupled / disconnected; Locking means for locking the rotation of the transfer unit around the coupling boss; It includes.

An embodiment of the image forming apparatus according to the present invention further includes positioning means for fixing the transfer unit to the pivot center so that the transfer unit is rotated about a predetermined position of the main body and pressed in the direction of the photosensitive member. .

Positioning means, the positioning projection provided in the transfer unit; A positioning unit formed in the main body and into which the positioning protrusion is inserted; An elastic stopper for bringing the positioning protrusions into close contact with the positioning parts; It includes.

Hereinafter, a preferred embodiment of an image forming apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic cross-sectional view of an electrophotographic image forming apparatus according to the present invention. Referring to FIG. 1, the electrophotographic image forming apparatus according to the present invention includes a printing unit 60, a cassette 70 for loading a recording medium, and a pickup roller 72 for pulling out a recording medium loaded on the cassette 70. And a feed roller 74 for transferring the picked up recording medium to the printing unit 60.

The printing unit 60 used for color printing includes four developments in which toners of different colors such as cyan, magenta, yellow, and black are accommodated. The cartridge 10C, 10M, 10Y, 10K, a transfer belt 20, four exposure parts 30C, 30M, 30Y, 30K, four transfer rollers 40, and a fixing part 50 are included.

Each of the exposure units 30C, 30M, 30Y, and 30K is configured to generate light corresponding to the image information of cyan, magenta, yellow, and black colors. According to the signal, scanning is carried out by the photosensitive member 11 provided in each of the developing cartridges 10C, 10M, 10Y, and 10K. A photosphere 17 is formed in the developing cartridges 10C, 10M, 10Y, and 10K so that light can be scanned from the exposure portions 30C, 30M, 30Y, and 30K to the photosensitive member 11.

Each developing cartridge 10C, 10M, 10Y, 10K includes a photosensitive member 11, a developing roller 12, a charging roller 13, a supply roller 14, and a toner layer regulating member 16. A charging bias is applied to the charging roller 13 to charge the outer circumference of the photosensitive member 11 to a uniform electric potential. A part of the outer peripheral surface of the photosensitive member 11 is exposed to the outside of the developing cartridges 10C, 10M, 10Y, and 10K and rotates in a predetermined direction. The outer circumferential surface of the photosensitive member 11 exposed to the outside of the developing cartridges 10C, 10M, 10Y, and 10K is opposed to the conveying belt 20.

The developing roller 12 supplies the toner contained in each of the developing cartridges 10C, 10M, 10Y, and 10K to an electrostatic latent image formed on the photosensitive member 11 to develop the toner image. A developing bias is applied to the developing roller 12 to develop the photosensitive member 11. A supply roller 14 for attaching toner to the developing roller 12 is provided outside the developing roller 12. A toner layer regulating member 16 for regulating the amount of toner attached to the developing roller 12 is provided in the developing cartridge frame 1.

The transfer unit 100 includes four transfer rollers 40, a transfer belt 20, a plurality of support rollers 21, 22, 23, and 24, and a transfer unit frame (not shown). The four transfer rollers 40 are disposed at positions opposite to the photosensitive members 11 of the developing cartridges 10C, 10M, 10Y, and 10K with the transfer belt 20 interposed therebetween. The transport belt 20 on the endless track is supported by a plurality of support rollers 21, 22, 23, 24. The conveyance belt 20 conveys the recording medium to the opposing surface of the photosensitive member 11 and the transfer roller 40. The toner image is transferred to the recording medium by the electrostatic force acting between the photosensitive member 11 and the transfer roller 40 to which the transfer bias voltage is applied, or the toner image is changed by the contact pressure between the photosensitive member 11 and the transfer roller 40. The recording medium is transferred. The transfer roller 40 is opposed to the photoconductor 11 while maintaining the conveyance belt 20 and a constant nip (a contact section between the photoconductor 11 and the conveyance belt 20 in which the transfer operation is performed).

The fixing unit 50 includes a heating roller 51 and a pressure roller 52 to fix the toner image to the recording medium by applying heat and pressure to the toner image transferred to the recording medium. The heating roller 51 is provided in the axial direction opposite to the pressure roller 52 as a heat source for permanently fixing the toner image. The pressure roller 52 is opposed to the heating roller 51 to apply a high pressure to the recording medium to fix the toner image to the recording medium. The recording medium on which the toner image is fixed is discharged out of the image forming apparatus by the discharge roller 76. The recording medium discharged from the discharge roller 76 along the recording medium transport path 80 is loaded into the loading unit 90.

The printing unit 60 shown in FIG. 1 includes four photosensitive members 11 that are independent for each color, and a single pass method in which four different color transfers are superimposed while transferring paper once. to be. In the single pass type color image forming apparatus, a full color image is formed while only one sheet is conveyed, and the same is true even when a black and white image is formed. The time required for color printing and black and white printing is the same. Therefore, it is mainly used for a high speed color image forming apparatus.

A color image forming apparatus operating in a relatively low speed region employs a multipass method that includes one photosensitive member and one exposure section and forms a color image by repeating exposure, development, and transfer for each color.

The two-pass method in which the two are compromised is provided with two photoconductors and two exposure units, and two developing cartridges are combined for each photoconductor and the exposure unit. Two cycles of exposure, development, and transfer are performed for each sheet of paper.

The present invention is not limited to the single pass method illustrated in FIG. 1, and various printing units for printing an image by an electrophotographic method may be employed. Although not shown in FIG. 1, the transfer unit may be attached or detached to a predetermined position of the main body by opening and closing the door member as well as the case where the printing unit is dedicated to black and white printing, as well as the four-pass or two-pass method.

2 is a perspective view showing main parts of the transfer unit 100 and the door member 200 of the present invention. Referring to this, the transfer unit 100 is provided with a coupling protrusion 110, a pressing surface 120, a hook portion coupling groove 130, a positioning protrusion 140, the handle 150. The door member 200 is mounted to the main body 99 to be rotatable about the door member hinge 201. The door member 200 is provided with a locker 240 to lock the rotation of the door member 200. Door member 200 is provided with a coupling boss 210, the pressing means 220, the hook portion 230.

Coupling projection 110 includes a large diameter portion 111 that is a large diameter portion and a small diameter portion 112 that is a small diameter portion. Coupling protrusion 110 is inserted into the coupling boss 210 provided in the door member 200.

A portion of the coupling boss 210 is opened to facilitate the separation / mounting of the coupling protrusion 110. The coupling boss 210 has a portion of a length larger than the diameter of the small diameter portion 112 of the coupling protrusion 110 and smaller than the diameter of the large diameter portion 111 is opened. As the small diameter portion 112 passes through the opening, the door member 200 and the transfer unit 100 are coupled / separated. After the small diameter portion 112 passes through the opening, when the transfer unit 100 is rotated about the coupling protrusion 110, the small diameter portion 112 moves to a position outside the opening, so that the coupling protrusion 110 opens the opening. The coupling boss 210 does not pass and supports the coupling protrusion 110 to be rotatable.

The pressing surface 120 is a surface to which the pressing means 220 provided in the door member 200 contacts. The pressing means 220 and the pressing surface 120 are provided at a position where the plurality of transfer rollers 40 can secure a predetermined contact pressure with respect to the photosensitive member 11. As an embodiment of the pressing means 220, a compression coil spring is employed.

The locking means locks the rotation of the transfer unit 100 around the coupling boss 210 before the door member 200 is locked to the main body 99. The locking means includes a hook portion 230 provided in the door member 200 and a hook portion coupling groove 130 provided in the transfer unit 100 to insert the hook portion 230.

Hook portion 230 is provided with a pair on both sides of the door member 200. Referring to FIG. 6, a hook portion connecting shaft 231 for connecting a pair of hook portions 230 is installed, and the pair of hook portions 230 and the hook portion coupling groove ( It is preferred that 130) be fastened / disconnected at the same time.

Hook portion coupling groove 130 is a groove in which the hook portion 230 is provided in the door member 200 is an L-shape, protrudes on both sides of the transfer unit 100, fastening of the hook portion 230 The ends are chamfered to facilitate this.

The positioning protrusion 140 is inserted into the positioning unit 992 formed in the main body 99 to fix the transfer unit 100 to the correct installation coordinates of the main body 99. The positioning projection 140 rotates when the door member 200 is locked to the main body 99 and the transfer unit 100 is pressed in the direction of the photosensitive member 11 by the pressing means 220. It becomes the center point.

A guide rail 990 for guiding the positioning protrusion 140 to the positioning unit 992 is formed in the image forming apparatus main body 99. The positioning unit 992 is preferably shaped to support the positioning protrusions 140 at two or more points. In one embodiment, the positioning projection 140 has a cylindrical shape, the positioning unit 992 supports the three positioning projection 140 in the c-shape. When the elastic stopper 991 closely contacts the three-positioned positioning protrusion 140 to the positioning unit 992, the positioning protrusion 140 is restricted in movement in all directions. Since the positioning protrusion 140 is fixed by the positioning unit 992 and the elastic stopper 991, the transfer unit 100 has only the rotational freedom around the positioning protrusion 140.

Even if the dimensional tolerances of the entire surface of the guide rail 990 are not managed, by locally managing the dimensional tolerances of the positioning unit 992, the positioning protrusions 140 may be fixed to the correct position of the main body 99.

When the positioning protrusion 140 is separated from the positioning unit 992, when the door member 200 is opened with a force greater than that of the elastic stopper 991, the transfer unit 100 is separated from the main body 99.

Handle 150 is formed on the upper portion of the transfer unit 100 can be safely moved without dropping the transfer unit 100 when the transfer unit 100 detachable.

3 is a side cross-sectional view illustrating a state in which the transfer unit 100 is mounted to the door member 200, and FIG. 4 is a side cross-sectional view illustrating a process in which the door member 200 is mounted to the image forming apparatus main body 99. 5 is a side cross-sectional view showing a state in which the transfer unit 100 is mounted on the image forming apparatus main body 99. 3 to 5, the operation of detaching the transfer unit 100 by opening and closing the door member 200 will be described sequentially.

First, referring to FIG. 3, the small diameter portion 112 passes through the opening and the coupling protrusion 110 is inserted into the coupling boss 210. As the transfer unit 100 rotates, the small diameter portion 112 leaves the opening of the coupling boss 210, and the coupling boss 210 rotatably supports the coupling protrusion 110. By the operation of the lever 232, the hook portion 230 is locked to the hook portion coupling groove 130 and the transfer unit 100 is coupled to the door member 200.

When the door member 200 is opened as shown in FIG. 4, the pressing means 220 presses the pressing surface 120 of the transfer unit 100 coupled to the door member 200. Thus, the hook portion 230 is elastically supported in contact with the hook portion coupling groove 130, the coupling protrusion 110 is also elastically in close contact with one side in the coupling boss (210). The rotation of the transfer unit 100 in the direction away from the door member 200 is locked by the hook portion 230.

Referring to FIG. 5, the positioning protrusion 140 is inserted into the positioning unit 992, and the elastic stopper 991 elastically fixes the positioning protrusion 140 to predetermined coordinates of the main body. The closed door member 200 is locked to the main body 99 by the rocker 240. The pressing means 220 elastically presses the transfer unit 100 toward the photosensitive member 11 to provide a predetermined contact force. When the positioning protrusion 140 is fixed to the positioning unit 992 and the door member 200 is locked to the main body 99 by the rocker 240, the transfer unit 100 contacts the photosensitive member 11. The pressing surface 120 further contracts the pressing means 220. Thus, the hook portion 230 is released from contact with the hook portion engaging groove 130 has a small separation distance. Coupling protrusion 110 also has a small play in the coupling boss (210). In the separation distance range, the rotation of the transfer unit 100 is not constrained by the hook portion 230 or the coupling boss 210.

The order of separating the transfer unit 100 from the main body 99 is the reverse of the above-described mounting process. First, the locking of the door member 200 is released. As the door member 200 is opened, the elastic force of the elastic stopper 991 is overcome and the positioning protrusion 140 is separated from the positioning unit 992. The positioning protrusion 140 is guided along the guide rail 990 and the transfer unit 100 is separated from the main body 99. The hook portion 230 is locked to the hook portion coupling groove 130 by the pressing means 220. Coupling protrusion 110 is also elastically in close contact with one side in the coupling boss (210). The rotation of the transfer unit 100 in the direction away from the door member 200 is locked by the hook portion 230. When the door member 200 is completely opened, the locking of the hook 230 is released by the operation of the lever 232 and the transfer unit 100 is separated from the door member 200. The transfer unit 100 is rotated about the coupling protrusion 110, the small diameter portion 112 passes through the coupling boss 210, the transfer unit 100 is separated from the door member 200. The separated transfer unit 100 is safely transported by the handle 150.

As described above, the image forming apparatus according to the present invention can be easily mounted / detached on the main body by opening and closing the door member, and based on the rotation center point assembled at the correct position by the positioning means. By this, the transfer unit can be pressed in the direction of the photosensitive member.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and those skilled in the art to which the art belongs can make various modifications and other equivalent embodiments therefrom. Will understand. Therefore, the true technical protection scope of the present invention will be defined by the claims below.

Claims (5)

An image forming apparatus main body having a photosensitive member on which a toner image is developed; A door member rotatably installed on the main body to open and close a part of the main body; A transfer unit coupled to the door member and transferring the toner image onto paper; Transfer unit coupling means for coupling the transfer unit and the door member; Pressing means for pressing the transfer unit coupled to the door member in the direction of a photosensitive member; Including; The transfer unit is rotated together in a state coupled to the door member, is pressed in the direction of the photosensitive member when the door member is closed, it is separated from the main body when the door member is opened. The method of claim 1, The transfer unit coupling means, A coupling protrusion provided on the transfer unit and including a large diameter portion having a large diameter and a small diameter portion having a small diameter; A coupling boss provided on the door member to rotatably support the coupling protrusion and having an opening through which the small diameter portion passes when the door member and the transfer unit are coupled / disconnected; Locking means for locking the rotation of the transfer unit around the coupling boss; Image forming apparatus comprising a. The method of claim 2, The locking means, A hook portion connecting shaft rotatably installed on the door member; A pair of hook portions provided at both ends of the hook portion connecting shaft; A hook portion coupling groove provided in the transfer unit and into which the hook portion is inserted during the locking; Image forming apparatus comprising a. The method according to any one of claims 1 to 3, And a positioning means for fixing the transfer unit to the pivot center point so that the transfer unit is rotated about a predetermined position of the main body toward the center point and pressed in the direction of the photosensitive member. The method of claim 4, wherein The positioning means, A positioning protrusion provided in the transfer unit; A positioning unit formed in the main body and into which the positioning protrusion is inserted; An elastic stopper for bringing the positioning protrusions into close contact with the positioning parts; Image forming apparatus comprising a.

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