JP2011145384A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a developer from leaking from the proximity of a supply port of a developer container, accompanying pulling out of a developing device, in an image forming apparatus where the developer container 103 and the developing device 4 are disposed as separate units. <P>SOLUTION: The edge of an opening 103, opening toward the developing device 4, is positioned outside a range where a magnet roller 102 can magnetically carry the developer. The whole surface of the developer container 101, facing the developing device 4, is positioned outside the range where the magnet roller 102 can magnetically carry the developer via the developer container 101. As a result, magnetic force leak and the developer adhering to the outside of the edge of the opening 103 are and the closest outer wall surface located directly under the magnet roller 102 are less apt to occur and to drop. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image forming apparatus that can be removed from a housing by moving the developing device in a direction in which the developer carrying member is withdrawn from the image carrier, and more specifically, between the removed developing device and the developer container remaining on the housing side. The present invention relates to a developer leakage prevention structure.

  2. Description of the Related Art An image forming apparatus including a developing device that develops an electrostatic image formed on an image carrier onto a toner image with a developer carried on the developer carrier is widely used. The developing device is attached to the housing of the image forming apparatus so that the image carrier and the developer carrier are opposed to each other with a predetermined gap (up to 300 μm).

  When the image carrier and the developing device are separately attached to the housing of the image forming apparatus, the developing device is provided with a guide mechanism that is independent from the image carrier. The conventional general developing device take-out structure is a structure in which the developing device is moved in the longitudinal direction of the image carrier and taken out to the front side of the image forming apparatus. However, a structure in which the developing device is moved away from the image carrier and taken out to the side of the image forming apparatus has been proposed (Patent Document 1).

  Patent Document 1 shows an image forming apparatus in which a developing device is rotated in a horizontal direction so that the developing device can be taken out from a casing. The manual operation member releases the fixing of the developing device, so that the developing device becomes an image carrier. It can be rotated in a direction away from.

  Patent Documents 2 and 3 show an image forming apparatus in which a developer container is disposed adjacent to a developing device and the developer is supplied to the developing device so as to supplement the developer (magnetic toner) consumed in image formation. Here, the magnetic rotating body (magnet roller) rotates while magnetically carrying the developer inside the developer replenishing port for the developing device, so that the developer in the developer container passes through the replenishing port to the developing device. Depressed.

Japanese Patent Laid-Open No. 11-327296 Japanese Patent Laid-Open No. 11-174843 Japanese Patent Laid-Open No. 11-305534

  A high-speed, large-volume image forming apparatus consumes a large amount of toner, and thus a large developer container is connected to the developing device. In this case, it is difficult to remove the developing device from the housing of the image forming apparatus with the developer container connected. In a state where a large amount of toner is accommodated, it is difficult to handle, transport, or replace a new one.

  Therefore, as shown in FIG. 3B, with the developer container (101) left in the housing (20), only the developing device (4) is horizontally moved away from the image carrier (1). A structure has been proposed in which the image is moved to the side surface of the image forming apparatus. However, in this case, as the developing device (4) is pulled out, the developer leaks from the vicinity of the replenishment port (103) of the developer container (101) remaining in the housing (20), and the housing ( 20) The inside was found to be dirty.

  An object of the present invention is to provide an image forming apparatus in which the developer is unlikely to leak from the vicinity of the replenishment port of the developer container as the developing device is pulled out.

  The image forming apparatus according to the present invention includes an image carrier, a developing device that carries the developer on the developer carrier and develops a toner image on the image carrier, and replenishment for supplying the developer to the developer. A developer container having an opening; a shutter member that opens and closes the replenishing opening; and a developer that is magnetically carried and rotated inside the replenishing opening to thereby rotate the developer in the developer container to the replenishing opening The replenishing port edge that opens toward the developing device is located outside the range in which the magnetic rotating member can carry the developer magnetically. It is what.

  In the image forming apparatus of the present invention, the developer hardly adheres to the outer surface of the developer container due to the magnetic force of the magnetic rotating body. Therefore, even if vibration or the like is applied as the developing device is pulled out, the developer is unlikely to leak from the vicinity of the replenishment port of the developer container.

1 is an explanatory diagram of a configuration of an image forming apparatus. It is explanatory drawing of a structure of a developing device. It is explanatory drawing of the mechanism for attachment or detachment of a developing device. It is explanatory drawing of the state of the toner in the opening part in a comparative example. It is explanatory drawing of the state in which the magnet roller carried the developer. 6 is an explanatory diagram of a state of toner in an opening according to Embodiment 1. FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention provides another embodiment in which a part or all of the configuration of the embodiment is replaced with the alternative configuration as long as the developing device can be taken out in the direction of separating the developer carrier from the image carrier. But it can be done.

  Therefore, it is carried out with an image forming apparatus equipped with a developing device that uses magnetic toner without distinguishing between charging method and electrostatic image forming method, and without distinguishing between intermediate transfer method, recording material conveyance method, transfer belt method, and sheet-fed printing method. it can.

  In the present embodiment, only main parts related to toner image formation will be described. However, the present invention includes a printer, various printing machines, a copier, a FAX, a multifunction machine, and the like in addition to necessary equipment, equipment, and a housing structure. Can be implemented in various applications.

  In addition, about the general matter of the image forming apparatus shown by patent documents 1-3, illustration is abbreviate | omitted and the overlapping description is abbreviate | omitted.

<Image forming apparatus>
FIG. 1 is an explanatory diagram of the configuration of the image forming apparatus. As shown in FIG. 1, the image forming apparatus 100 is a monochrome high-speed printer that transfers a toner image formed on a photosensitive drum 1 onto a recording material P carried on a transfer belt 14. The photosensitive drum 1 and the developing device 4 are detachably attached to the housing 20.

  A corona charger 2, an exposure device 3, a developing device 4, a transfer roller 5, and a drum cleaning device 6 are disposed around a photosensitive drum 1 that is an example of an image carrier. The photosensitive drum 1 has a photosensitive layer formed on the outer peripheral surface of an aluminum cylinder, and rotates in the direction of arrow R1 at a process speed of 700 mm / sec.

  The corona charger 2 irradiates charged particles accompanying corona discharge to charge the surface of the photosensitive drum 1 to a uniform negative potential. The exposure device 3 scans a scanning beam image data obtained by developing an input image with a rotating mirror, and writes an electrostatic image of the image on the surface of the charged photosensitive drum 1. The developing device 4 develops the electrostatic image formed on the photosensitive drum 1 into a toner image using a one-component developer.

  The transfer roller 5 presses the inner surface of the transfer belt 14 to form a transfer portion T <b> 1 between the photosensitive drum 1 and the transfer belt 14. The recording material P stored in the recording material cassette 11 a is separated one by one by the separation roller 12 a and sent to the registration roller 13. The registration roller 13 receives and waits for the recording material P in a stopped state, and sends the recording material P to the transfer portion T1 in synchronization with the toner image on the photosensitive drum 1.

  By applying a positive DC voltage to the transfer roller 5, the toner image carried on the photosensitive drum 1 is transferred to a recording material carried on the transfer belt 14 and passing through the transfer portion T1. The drum cleaning device 6 rubs the photosensitive drum 1 with a cleaning blade to collect the transfer residual toner remaining on the photosensitive drum 1 by escaping from the transfer to the recording material P.

  The recording material P to which the toner image has been transferred is separated from the transfer belt 14 in curvature and sent to the fixing device 7, and is heated and pressurized by the fixing device 7 to thermally fix the toner image on the surface, and then passes through the discharge roller 15. It is discharged to the discharge tray 16.

<Developing device>
FIG. 2 is an explanatory diagram of the configuration of the developing device. FIG. 3 is an explanatory diagram of a mechanism for attaching and detaching the developing device. FIG. 4 is an explanatory diagram of the state of toner in the opening in the comparative example. As shown in FIG. 2, the developing device 4 develops a toner image on the photosensitive drum 1 by causing a developer to be carried on a developing sleeve 4 a which is an example of a developer carrying member. The developing device 4 carries the developer (magnetic toner) in a thin layer state on the developing sleeve 4a rotating around the fixed magnet 4b, and conveys the developer to the portion facing the photosensitive drum 1.

  The layer thickness regulating blade 4c regulates the layer thickness of the developer carried on the developing sleeve 4a and charges the developer by rubbing. The power source D4 applies an oscillating voltage obtained by superimposing an AC voltage to a DC voltage to the developing sleeve 4a, thereby charging and transferring the developer carried on the developing sleeve 4a to the photosensitive drum 1, thereby reversing the electrostatic image. Develop to form a toner image.

  As shown in Patent Documents 2 and 3, a developer container 101 for replenishing toner is provided immediately above the developing device 4. The developer container 101 stores the developer, and rotates the magnet roller 102 to cut out the developer corresponding to the amount consumed in image formation and supply it to the developing device 4.

  Inside the opening 103 provided in the lower part of the developer container 101, a magnet roller 102 having a length that is approximately the maximum sheet passing width is provided substantially in parallel with the developing sleeve 4a. The developer replenished from the toner supply unit (not shown) is buffered in the developer container 101, and the toner is uniformly replenished in the developing sleeve arrangement direction of the developing device 4 by rotating the magnet roller 102. By uniformly replenishing the toner in the developing sleeve arrangement direction, the toner agent surface in the developing sleeve arrangement direction is less likely to be inclined in the developing device 4 with the toner replenishment, and the image density is adjusted in the developing sleeve arrangement direction. It is effective to keep it uniform.

  However, the developer containers disclosed in Patent Documents 1 and 2 are provided so as to be integrally fixed with the developing device, and a large opening is required in the housing of the image forming apparatus in order to attach and detach the developing device. Become. In order to provide a large opening, it is necessary to increase the strength of the housing, leading to an increase in size and weight of the image forming apparatus. In addition, when the developing device is replaced, the developer container is also automatically replaced, which increases the running cost.

  Therefore, as shown in FIG. 3A, the developing device 4 and the developer container 101 are set as separate units, and when the developing device 4 is replaced, the long-life developer container 101 is mounted on the casing 20. A method has been proposed in which only the developing device 4 is exchanged while leaving the state. A configuration is also added in which when the developing device 4 is removed, the lower opening 103 of the developer container 101 is closed by the shutter 104.

  That is, the rail 22, which is an example of a guide mechanism, guides the developing device 4 so that the developing device 4 can be removed from the housing 20 in a direction in which the developing sleeve 4 a is separated from the photosensitive drum 1. The developer container 101 has an opening 103 that is an example of a developer supply port that is connected to and separated from the developing device 4 as the developing device 4 guided by the rail 22 moves. The magnet roller 102, which is an example of a magnetic rotator, supplies the developer in the developer container 101 to the developing device 4 through the opening 103 by rotating while carrying the developer magnetically inside the opening 103. To do.

  As shown in FIG. 3B, the shutter 104, which is an example of a shutter member, moves along the surface of the developer container 101 facing the developing device 4 to open and close the opening 103. As the developing device 4 is pulled out, the shutter 104 is pushed by the shutter actuator 24 of the resin spring attached to the developing device 4 and moves along the bottom surface of the developer container 101. When the shutter 104 closes the opening 103 and stops at the limit position, the shutter actuator 24 is deformed to pass through the surface of the shutter 104 and the developing device 4 is taken out from the housing 20.

  When the developing device 4 is attached, the shutter 104 is pushed by the shutter actuator 24 and moves along the bottom surface of the developer container 101, and the shutter 104 is retracted from the opening 103. When the opening 103 is opened and the shutter 104 is stopped at the limit position, the shutter actuator 24 is deformed and passes through the surface of the shutter 104 to be positioned at a position where the developing device 4 can be developed.

<Comparative example>
Conventionally, a developer container (buffer device) for uniformly supplying developer in the longitudinal direction of the developing sleeve 4a has been provided integrally with the developing device, resulting in an increase in running cost and an increase in the size of the image forming apparatus. It was. As a solution to this problem, a configuration is adopted in which the developer container and the developing device are formed as separate units and a shutter for attaching / detaching the developing device is provided below the fixed developer container. However, with such a configuration, there has been a problem that some toner leaks from the shutter.

  As shown in FIG. 4, the shutter 104 interferes with a portion 110 of the developer 108 that is held in the opening 103 by the magnet roller 102 and protrudes from the developer container 101. For this reason, it has been found that the developer scatters and falls onto the upper surface of the developing device 4 or leaks out to the surroundings.

  In the following embodiments, in order to prevent such scattering of the developer, a configuration is adopted in which the magnetic roller 102 does not interfere with the developer held by magnetic force when the shutter 104 is operated. As a result, the developer leakage when the developing device 4 and the developer container 101 are configured as separate units is greatly reduced, and the developing device 4 can be attached and detached.

<Example 1>
FIG. 5 is an explanatory diagram of a state in which the magnetic roller carries the developer. FIG. 6 is an explanatory diagram of the state of toner in the opening according to the first exemplary embodiment.

  As shown in FIG. 2, a developer container (buffer device) 101 for evenly replenishing toner in the longitudinal direction of the developing sleeve 4 a of the developing device 4 is disposed immediately above the developing device 4. A magnet roller 102 that rotates while holding the developer is disposed below the developer container 101, and an opening 103 for delivering the developer to the developing device 4 is provided below the magnet roller 102. A shutter 104 for closing the opening 103 is provided under the opening 103 of the developer container 101. When the developing device 4 is taken out, the shutter 104 is closed and the developer from the opening 103 is removed. It is configured to prevent leakage.

  In the first embodiment, the edge of the opening 103 that opens toward the developing device 4 is positioned outside the range in which the magnet roller 102 can carry the developer magnetically. The entire surface of the developer container 101 facing the developing device 4 is located outside the range in which the magnet roller 102 can carry the developer magnetically via the developer container 101. For this reason, it is difficult for the developer to adhere to the outer side of the edge of the opening 103 due to the leakage of the magnetic force or the closest outer wall surface directly below the magnet roller 102.

  The magnet roller 102 is arranged so as to be biased toward the photosensitive drum 1 side (image carrier side) from the center of the opening 103 in the moving direction of the developing device 4. Therefore, the range in which the magnetic force of the magnet roller 102 is applied and the developer hangs away from the opening 103, and the developer adsorbed on the magnet roller 102 is difficult to protrude from the opening 103. Since most of the developer hung from the magnet roller 102 is located on the inner wall surface of the developer container 101 that is displaced from the opening 103, it is difficult to leak out from the opening 103 even when it is dropped due to vibration. It has become.

  Further, the gap between the inner wall surface (bottom surface) of the developer container 101 to which the developer is conveyed and the magnet roller 102 gradually increases from the inlet side toward the opening 103. As a result, the room for storing the developer dropped from the magnet roller 102 on the inner wall surface of the developer container 101 is increased to make it difficult to turn to the opening 103. It is also possible to prevent the developer from being blocked around the magnet roller 102 and increasing the rotational resistance.

  As shown in FIG. 5A, a plurality of magnetic poles are formed in the circumferential direction of the magnet roller 102, and a magnetic pattern 109 having a large magnetic force on the magnetic poles and a small magnetic force between the magnetic poles is formed. According to the magnetic pattern 109, a developer is carried around the magnet roller 102 as shown in FIG. The toner layer 108 formed on the surface of the magnet roller 102 when the developer is held on the surface of the magnet roller 102 at maximum in the use environment air has the maximum thickness h1 and the minimum thickness of the held developer. And h2.

  As shown in FIG. 5B, the thinnest developer thickness is set to h2 in the state where the magnet roller 102 holds the developer maximum in the air and is held in a horizontal state, and the thickest developer thickness is set to h2. Let h1 be. As shown in FIG. 2, the shortest distance in the gap between the developer container 101 and the magnet roller 102 toward the opening 103 is B1, and the edge from the edge of the opening 103 toward the developing device 4 to the magnet roller 102 is shown. Let the shortest distance be A1. The shortest distance from the surface of the developer container 101 facing the developing device 4 to the magnet roller 102 is A2.

At this time, in the first embodiment, the shape of the magnetic force pattern 109 and the opening 103 of the magnet roller 102 is controlled so as to establish the following relationship. For this reason, as shown in FIG. 6, the developer that is magnetically attracted and supported by the magnet roller 102 does not have to protrude into the path of the shutter 104. As a result, the amount of developer that protrudes from the opening 103 to the bottom surface of the developer container 101 and is cut by the shutter 104 and falls is smaller than that in the comparative example of FIG.
B1 <h2
h1 <A1
h1 <A2

<During image formation>
As shown in FIG. 2, during the image forming operation, the developer is transferred from the rotating developing sleeve 4a to the rotating photosensitive drum 1 for development, and then the toner image is transferred from the rotating photosensitive drum 1 to the recording material. Transcribed. At this time, the developer in the developing device 4 is consumed by the developer flowing out from the developing sleeve 4a to the photosensitive drum 1. When the consumption has progressed to a certain extent, a shortage of developer is detected by a sensor 105 provided in the developing device 4. Then, the magnet roller 102 rotates and a control for cutting out a predetermined amount of developer from the developer container 101 and supplying it to the developing device 4 is executed.

  When replenishing the developer from the developer container 101 to the developing device 4, the magnet roller 102 rotates and rotates while holding the toner in the developer container 101. The toner layer 108 held around by the magnet roller 102 is guided to the magnet roller coat restricted area 106 and comes out to the opening 103. At this time, the magnet roller 102 tries to hold more toner (minimum thickness h2) than the width B1 of the restricted area, but is limited to a uniform coating amount (layer thickness B1) in the magnet roller coat restricted area 106.

  Therefore, a uniform amount of developer 111 is conveyed to the opening 103 with respect to the rotation of the magnet roller 102 in the longitudinal direction of the magnet roller 102. The developer 111 that has been transported uniformly is collected from the magnet roller 102 while collecting in the area in front of the scraping portion 107 in the scraping portion 107 having a uniform gap (width B2) in the longitudinal direction of the magnet roller 102. It is scraped off and supplied to the developing device 4.

  The developer 111 that has been uniformly transported to the opening 103 as described above is scraped off by the scraping portion 107 that is uniformly provided in the longitudinal direction. For this reason, the developing device 4 can be replenished with a uniform amount of developer by subtracting the distance B2 from the distance B1 in the longitudinal direction of the developing sleeve 4a (longitudinal direction of the magnet roller 102).

<When attaching / detaching the developing device>
During maintenance of the developing device 4, the shutter 104 is closed and the developing device 4 is attached and detached in order to prevent leakage of the developer. At this time, the maximum thickness h1 of the toner is smaller than the distance A1 from the surface of the magnet roller 102 to the edge of the opening 103, and the maximum thickness h1 of the toner is from the sliding surface D of the shutter 104. It is smaller than the distance A2.

  (1) By setting h1 <A1, the developer is not held by the magnet roller 102 on the shutter sliding surface C of the opening 103. Accordingly, it is possible to prevent the developer from leaking out of the developer container 101 due to the toner interfering with the shutter 104 when the shutter is opened and closed. On the other hand, if the developer is cut off by the shutter 104 at the shutter sliding surface C, the developer leaks out of the developer container 101.

  (2) By setting h1 <A2, even if there is toner floating outside the developer container 101, the toner is not attracted by the magnet roller 102 in the developer container 101. For this reason, the shutter 104 can move without interfering with the toner layer 108 held by the magnet roller 102, and the leakage of the developer can be greatly reduced.

  According to the first embodiment, the developer container (buffer device) for uniformly supplying the developer in the longitudinal direction of the developing sleeve and the developing device are separated into separate units, thereby reducing running costs and downsizing the housing. Is realized. The problem caused by the separate unit, that is, the leakage of toner from the developer container when the developing device is attached or detached, is greatly reduced.

  Specifically, as described above, the toner holding surface of the magnet roller disposed in the lower part of the developer container, the end position of the opening, and the vertical position of the shutter are defined. As a result, the shutter does not interfere with the developer held on the magnet roller, and toner fall from the developer container or from the outer wall surface can be greatly reduced.

  According to the first embodiment, it is possible to realize a developer container lower shutter structure in which the running cost is reduced and the housing is downsized, and at the same time, the scattering of toner when the developing device is attached and detached is greatly reduced.

DESCRIPTION OF SYMBOLS 1 Photosensitive drum (image carrier), 2 Corona charger, 3 Exposure apparatus 4 Developing apparatus, 4a Developing sleeve (developer carrier), 4b Fixed magnet 5 Transfer roller, 6 Drum cleaning apparatus, 8 Developer supply apparatus 20 Housing Body, 21 outer cover, 22 rails (guide mechanism)
23 pressing mechanism, 23A pressing spring, 23B fixing hook 24 actuator, 25 shutter,
DESCRIPTION OF SYMBOLS 101 Developer container, 102 Magnet roller, 103 Opening part 104 Shutter, 105 Sensor, 106 Magnet roller coat | court restriction | limiting area 107 Scraping part, 108 Toner layer, 109 Magnetic pattern 110 Toner which contacts a shutter, 111 Uniform conveyance to an opening part Toner

Claims (6)

An image carrier;
A developing device for developing a toner image on the image carrier by carrying the developer on the developer carrier; and
A developer container having a replenishing port for replenishing the developer to the developing device;
A shutter member for opening and closing the supply port;
A magnetic rotator for supplying the developer in the developer container to the developing device through the replenishing port by rotating the developer magnetically inside the replenishing port; and
An image forming apparatus, wherein an edge of the replenishing port that opens toward the developing device is located outside a range in which the magnetic rotating body can carry the developer magnetically. A housing to which the image carrier and the developing device are attached, and a guide mechanism for removably guiding the developing device in a direction to separate the developer carrier from the image carrier.
2. The image forming apparatus according to claim 1, wherein the replenishing port is connected to and separated from the developing device in accordance with the movement of the developing device guided by the guide mechanism.   The magnetic rotator is arranged so as to be biased toward the image carrier relative to the center of the replenishing port in the moving direction of the developing device, and a gap between the developer container to which the developer is conveyed and the magnetic rotator is 3. The image forming apparatus according to claim 2, wherein the image forming apparatus gradually expands toward the replenishing port. The shutter member moves along the surface of the developer container facing the developing device to open and close the supply port;
4. The surface of the developer container facing the developing device is outside a range in which the magnetic rotating body can magnetically support the developer via the developer container. Image forming apparatus. With the magnetic rotator carrying the maximum amount of developer in the air, the thinnest developer thickness is h2, the thickest developer thickness is h1, and the developer container and the magnetic rotation toward the supply port When the shortest distance in the gap between the bodies is B1, and the shortest distance from the edge of the replenishing port opened toward the developing device to the magnetic rotating body is A1,
5. The image forming apparatus according to claim 4, wherein B1 <h2 and h1 <A1. When the shortest distance from the surface of the developer container facing the developing device to the magnetic rotating body is A2,
6. The image forming apparatus according to claim 5, wherein h1 <A2.

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