JP2005321762A - Developing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device in which curling of a flexible member disposed in an opening opposite to an image carrier is prevented by a comparatively simple configuration, and to provide an image forming apparatus. <P>SOLUTION: The developing device 8 develops an electrostatic latent image formed on the image carrier. The developing device 8 includes a flexible member 87 disposed in the lengthwise direction of the opening opposite to the image carrier so as to project toward and abut on the image carrier. The developing device 8 also includes a restraining member 102 disposed at the lengthwise ends of the flexible member 87 and used for restraining the flexible member 87 from curling. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus using an electrophotographic method such as a copying machine, a printer, a facsimile, or a multifunction machine thereof, and a developing device installed there.

  Conventionally, in a developing device installed in an image forming apparatus such as a copying machine, a flexible member is installed in an opening where a developer carrying member facing the image carrying member is exposed to prevent toner scattering from the opening. The technique which performs is known (for example, refer patent document 1).

  Specifically, in Patent Document 1 and the like, a flexible member (film seal) is installed along the longitudinal direction of the opening of the developing device. A developer carrier (developing roller) is rotatably supported in the opening. The flexible member is located on the upstream side of the opening in the rotation direction of the developer carrier at the opening, and protrudes toward the image carrier (photosensitive drum) so as to contact the image carrier. It is affixed to.

As a result, the gap between the opening of the developing device and the image carrier is sealed, and the problem that the toner accommodated in the developing device is scattered from the gap to the outside of the device is suppressed. Note that when the toner scattered from the developing device adheres to the charging unit or the optical unit, the image quality of the output image is deteriorated.
Here, many image forming apparatuses are configured to be detachable from the main body of the image forming apparatus so that the developing device and the image carrier can be individually maintained.

  On the other hand, in Patent Document 2 and the like, for the purpose of eliminating impurities deposited on the contact surface of the cleaning blade that contacts the image carrier in order to clean the image carrier (latent image carrier), A technique is disclosed in which the image carrier is rotated in the direction opposite to the normal rotation direction after the image forming process is completed.

Japanese Patent Laid-Open No. 10-10864 JP-A-8-166754

  In the conventional image forming apparatus described above, the flexible member installed in the opening of the developing device remains turned up when the image carrier and the developing device are maintained or when the image carrier is rotated in the reverse direction. As a result, toner scattering may occur.

  Specifically, in a conventional image forming apparatus, when a developing device or an image carrier is maintained, an operation for attaching or detaching them to / from the image forming apparatus main body is usually performed. That is, the developing device and the image carrier are taken out from the apparatus main body, and are attached to the apparatus main body after their maintenance (replacement or repair) is completed.

  Here, in the case of an image forming apparatus in which the developing device and the image carrier are attached to and detached from the apparatus main body in the longitudinal direction of the developing device and the image carrier, when the developing device and the image carrier are attached and detached, The flexible member installed in the opening of the developing device sometimes turned up. Specifically, in the case of an image forming apparatus configured to mount the image carrier in a state where the developing device is first mounted on the apparatus main body, a protruding portion (tip portion) of a flexible member installed in the developing device ) May be caught by the end flange of the image carrier mounted in the longitudinal direction. Also, in the case of an image forming apparatus configured to mount the developing device with the image carrier first mounted on the apparatus main body, the longitudinal end of the protruding portion of the flexible member extends in the longitudinal direction. In some cases, the image was caught on the edge of the image carrier.

  Further, as in Patent Document 2 and the like, in an image forming apparatus that rotates an image carrier in a direction opposite to the normal rotation direction after the image forming process is completed, the image carrier follows the normal rotation direction of the image carrier. In some cases, the flexible member in contact with the image carrier is turned in the direction opposite to the normal contact direction due to the reverse rotation of the image carrier.

  As described above, when the flexible member attached to the developing device is turned in the direction opposite to the normal contact direction and left in that state for a long time, the flexible member is turned over. May be attached. Then, even if the image carrier is rotated in the normal direction thereafter, the turned-up state may not be resolved. When the image forming apparatus is operated with the flexible member turned up, the sealing performance at the opening of the developing device is lowered, and the toner is scattered from the opening. When the scattered toner adheres to the charging unit or the optical unit, an abnormal image such as a charging failure or a blank image is generated in the output image.

  In order to solve such a problem, a measure of sticking both ends in the longitudinal direction of the protruding portion of the flexible member to the case of the developing device with a double-sided tape or the like can be considered. However, in this case, there is an influence caused by the flexible member protruding toward the image carrier being deformed depending on the use environment. That is, since both ends in the longitudinal direction of the flexible member are fixed to the case, the shape is distorted in the longitudinal direction when the usage environment changes and the flexible member expands and contracts. Specifically, in a high-temperature and high-humidity environment, the flexible member expands, and thus the flexible member is wavy. As described above, when the flexible member is undulated, a gap is formed between the flexible member and the image carrier on which the flexible member abuts, and toner scattering occurs from the gap.

  SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has a relatively simple configuration and a developing device and an image in which a flexible member installed in an opening facing the image carrier does not turn over. It is to provide a forming apparatus.

  A developing device according to a first aspect of the present invention is a developing device for developing a latent image formed on an image carrier, and is installed along the longitudinal direction of an opening facing the image carrier. A flexible member that protrudes toward the image carrier and abuts against the image carrier, and a regulating member that is installed at the end in the longitudinal direction and restricts turning of the flexible member And.

  According to a second aspect of the present invention, there is provided the developing device according to the first aspect, wherein the regulating member covers the end of the flexible member in the longitudinal direction from the image carrier side. This is a flexible member.

  According to a third aspect of the present invention, in the developing device according to the second aspect, the second flexible member protrudes toward the image carrier. The two positions sandwiching the part are pasted as the pasting surface.

  According to a fourth aspect of the present invention, there is provided the developing device according to the third aspect, wherein a third flexible member is provided at an end in the longitudinal direction of the opening, One is a position on the third flexible member.

  According to a fifth aspect of the present invention, there is provided a developing device according to the third or fourth aspect of the present invention, comprising a case to which the flexible member is adhered, wherein one of the adhesion surfaces is provided. The position is on the case.

  According to a sixth aspect of the present invention, in the developing device according to any one of the second to fifth aspects, the second flexible member is made of polyurethane rubber.

  A developing device according to a seventh aspect of the present invention is the developing device according to any one of the second to sixth aspects, wherein the developing device is exposed from the opening toward the image carrier and a magnet is provided therein. The second flexible member is provided 4 ± 1 mm away from the magnet in the longitudinal direction.

  The developing device according to an eighth aspect of the present invention is the developing device according to the seventh aspect, wherein the magnet has a peak magnetic force in a direction opposite to the image bearing member of 45 to 60 mT at the end in the longitudinal direction. It was formed to become.

  According to a ninth aspect of the present invention, there is provided the developing device according to any one of the first to eighth aspects, wherein the developing device is exposed from the opening toward the image carrier and is rotatably supported. In addition, one or a plurality of developer carriers are provided, and the flexible member is installed on the upstream side in the rotation direction of the developer carrier in the opening.

  A developing device according to a tenth aspect of the present invention is the developing device according to any one of the first to ninth aspects, wherein the flexible member is made of polyurethane rubber.

  According to an eleventh aspect of the present invention, the developing device according to any one of the first to tenth aspects is configured to be detachable from the image forming apparatus main body.

  An image forming apparatus according to a twelfth aspect of the present invention includes the developing device according to any one of the first to eleventh aspects and the image carrier in a main body of the image forming apparatus. .

  An image forming apparatus according to a thirteenth aspect of the present invention is the image forming apparatus according to the twelfth aspect of the present invention, wherein the image carrier is configured to be detachable from the main body of the image forming apparatus with the longitudinal direction as the detachable direction. It has been done.

  In the present invention, a restricting member for restricting turning of the flexible member is provided at the longitudinal end of the flexible member provided in the opening facing the image carrier. As a result, it is possible to provide a developing device and an image forming apparatus in which the flexible member is prevented from being turned over with a relatively simple configuration, and toner scattering does not occur.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the part which is the same or it corresponds, The duplication description is simplified or abbreviate | omitted suitably.

Embodiment 1 FIG.
The first embodiment of the present invention will be described in detail with reference to FIGS.
First, the configuration and operation of the entire image forming apparatus will be described with reference to FIG.
In FIG. 1, 1 is an apparatus main body (image forming apparatus main body) of a copying machine, 2 is a photosensitive drum as an image carrier, 3 is a first charging unit that charges the photosensitive drum 2, and 4 is an image of a document D. An exposure unit that emits exposure light L based on information, 6 is a second charging unit corresponding to the second development step, 7 is an LED array (second exposure unit) corresponding to the second development step, and 8 is a first development step. The first developing device of the two-component developing system corresponding to the above, 9 is a toner replenishing unit for supplying fresh toner to the first developing device 8, and 10 is for transferring the toner image formed on the photosensitive drum 2 to the transfer material P 11 is a cleaning unit that collects untransferred toner on the photosensitive drum 2, 12 is a neutralizing unit that resets the surface potential on the photosensitive drum 2, and 18 is a one-component development system corresponding to the second development step. 2 shows a second developing device.

  Reference numeral 20 denotes a document reading unit that reads image information of the document D, 21 denotes a CCD (imaging device) on which image information of the document D is optically formed, and 26 conveys the transfer material P toward the transfer unit 10. A registration roller pair 27, a transfer belt 27 for guiding the transfer material P after the transfer process to the fixing unit 18, and a fixing unit 28 for fixing the toner image on the transfer material P after the transfer process.

Hereinafter, an operation during image formation in the image forming apparatus will be described.
First, the document reading unit 20 optically reads the image information of the document D placed thereon. Specifically, the reflected light corresponding to the black image information on the document D and the reflected light corresponding to the red image information on the document D are reflected on the CCD 21 via optical elements such as a mirror, a lens, and an optical filter. Is imaged.
Thereafter, the optical image information read by the document reading unit 20 is transmitted to the exposure unit 4 via the memory control unit. The exposure unit 4 emits exposure light L (laser light) based on black image information toward the photosensitive drum 2.

  On the other hand, the photosensitive drum 2 is driven by a drive motor (not shown) and rotates clockwise in the drawing. First, the surface of the photosensitive drum 2 is uniformly charged to about −900 volts at a position facing the first charging unit 3 of the scorotron charge method. Then, the surface of the photosensitive drum 2 charged by the first charging unit 3 reaches the irradiation position of the exposure light L. At this position, an electrostatic latent image corresponding to black image information is formed. Here, the potential of the surface of the photosensitive drum 2 on which the electrostatic latent image is formed is about −100 volts.

  Thereafter, the surface of the photosensitive drum 2 on which the latent image is formed reaches a portion (developing area) facing the first developing device 8. Then, the black toner in the two-component developer carried on the two developing rollers of the first developing device 8 adheres to the latent image on the photosensitive drum 2 to form a black toner image (first image). Development process.) Here, a developing bias of −550 volts is applied to the developing roller of the first developing device 8. A gap (development gap) of about 0.5 to 1.0 mm is provided between the developing roller and the photosensitive drum 2. The toner replenishing unit 9 supplies toner to the first developing device 8 in accordance with toner consumption in the first developing device 8. The configuration and operation of the first developing device 8 will be described in detail later.

  Thereafter, the surface of the photosensitive drum 2 on which the black toner image is formed is charged again to about −900 volts at a position facing the second charging unit 6. Then, the surface of the photosensitive drum 2 charged by the second charging unit 6 reaches the irradiation position of the LED array 7. Then, an electrostatic latent image corresponding to red image information is formed at this position. Here, the potential of the surface of the photosensitive drum 2 on which the electrostatic latent image is formed is about −100 volts.

  Thereafter, the surface of the photosensitive drum 2 on which the second latent image is formed reaches a portion (development region) facing the second developing device 18. Then, the red toner (one-component nonmagnetic developer) carried on the developing roller of the second developing device 18 adheres to the second latent image on the photosensitive drum 2 to form a red toner image. (Second development step). Here, a DC developing bias of −750 volts is applied to the developing roller of the second developing device 18.

Thereafter, the surface of the photosensitive drum 2 on which the black toner image and the red toner image are formed without color mixture reaches a portion facing the transfer unit 10. At this position, the two-color toner images on the photosensitive drum 2 are transferred onto the transfer material P conveyed by the registration roller pair 26.
At this time, a small amount of untransferred toner that is not transferred onto the transfer material P remains on the photosensitive drum 2.

Thereafter, the surface of the photosensitive drum 2 having untransferred toner that has passed through the transfer unit 10 reaches a portion facing the cleaning unit 11. In the cleaning unit 11, untransferred toner adhering to the drum surface is collected by the cleaning blade 11 a that contacts the photosensitive drum 2 and the cleaning roller.
Thereafter, the surface of the photosensitive drum 2 that has passed through the cleaning unit 11 reaches the static elimination unit 12. Then, the residual potential on the surface of the photosensitive drum 2 is removed here, and a series of image forming processes is completed.

  Here, the transfer material P is fed from a paper feed unit (not shown) in which a plurality of transfer materials are accommodated. The transfer material P that has reached the position of the registration roller pair 26 from the paper feeding unit is conveyed to the transfer unit 10 by the registration roller pair 26 in synchronization with the toner image on the photosensitive drum 2. As described above, the transfer unit 10 transfers the toner image onto the transfer material P.

Then, the transfer material P after the transfer process is conveyed to the position of the fixing unit 28 by a transfer belt 27 that is driven by a drive motor (not shown) and travels in the direction of the arrow in the drawing. The fixing unit 28 fixes the unfixed toner image on the transfer material P. Here, the transfer belt 27 traveling in the direction of the arrow is cleaned at the position of the belt cleaning unit 30 provided with a blade 30 a that contacts the transfer belt 27.
Thereafter, the transfer material P after the fixing process is discharged out of the image forming apparatus main body 1 as an output image.
Thus, a series of image forming processes is completed.

The drive motor that rotationally drives the photoconductive drum 2 moves the photoconductive drum 2 in a direction opposite to the normal rotation direction (counterclockwise in FIG. 1) after the above-described image forming process is completed. It is controlled to rotate slightly. Thereby, impurities deposited on the contact surface of the cleaning blade 11a are removed from the contact surface.
Similarly, the drive motor that drives the transfer belt 27 is also controlled so that the transfer belt 27 slightly travels in the direction opposite to the normal travel direction after the above-described image forming process is completed. Thereby, impurities accumulated on the contact surface of the blade 30a are removed from the contact surface.

In the first embodiment, the maintenance of the photosensitive drum 2 and the first developing device 8 is performed according to the following procedure.
First, the door (not shown) of the apparatus body 1 is opened. Next, the second developing device 18 is pulled out in the longitudinal direction (the direction perpendicular to the paper surface of FIG. 1) and detached from the apparatus main body 1. Next, the transfer belt 27 is moved downward by operating the lever, and the contact state with the photosensitive drum 2 is released. Then, after the first charging unit 3 and the like are pulled out in the longitudinal direction and separated from the apparatus main body 1, the photosensitive drum 2 is pulled out in the longitudinal direction and detached from the apparatus main body 1. Finally, the first developing device 8 is pulled out in the longitudinal direction and detached from the apparatus main body 1. In this way, the detaching operation of the photosensitive drum 2 and the first developing device 8 from the apparatus main body 1 is completed. The mounting operation of the photosensitive drum 2 and the first developing device 8 to the apparatus main body 1 is performed in the reverse procedure to the above-described detachment operation.

Next, the first developing device (developing device) 8 that is detachably installed in the image forming apparatus main body 1 will be described in detail with reference to FIGS.
2 is a cross-sectional view showing the developing device 8, and FIG. 3 is a perspective view of the end portion of the developing device 8 of FIG. 2 as viewed from the photosensitive drum 2 side.

  Referring to FIG. 2, 80 is an opening facing the photosensitive drum 2, 81 is a first developing roller as a developer carrying member exposed from the opening 80 toward the photosensitive drum 2, and 82 is an opening 80. The second developing roller as a developer carrying member exposed from the photosensitive drum 2 to the photosensitive drum 2, 83 is a paddle roller for supplying the developer to the first developing roller 81, and 84 is a stirring roller having a plurality of elliptical plates in the longitudinal direction. , 85 is a doctor blade disposed so that the tip thereof faces the first developing roller 81, 86 is a case to which an inlet seal 87 is attached, and 87 is a flexible member that protrudes and contacts the photosensitive drum 2. 88 is a stirring plate for stirring the developer in the apparatus in the longitudinal direction, 89 is a conveying screw for stirring the developer in the apparatus in the longitudinal direction, and 100 is in the developing apparatus 8. Toner amount Showing a toner density sensor for Gosuru.

Hereinafter, the operation of the developing device 8 will be described in detail.
The two developing rollers 81 and 82 rotate in the direction of the arrow in FIG. The developer in the apparatus is agitated and mixed in the longitudinal direction and in a direction orthogonal to the agitating roller 84 and the conveying screw 89 and the agitating plate 88 rotating in the direction of the arrow. Then, the toner that is frictionally charged and adsorbed on the carrier is supplied to the first developing roller 81 together with the carrier by the paddle roller 83, and the developer is carried on the first developing roller 81.

  At this time, the toner stored in the toner replenishing portion 9 is conveyed to the position of the replenishing roller 92 by the stirring member 91, and the toner is appropriately replenished into the developing device 8 from the replenishing roller 92 through the replenishing port. Note that the toner in the toner replenishing unit 9 is appropriately stored in the developing device 8 based on the detection result of the toner concentration sensor 100 that detects the toner concentration in the developing device 8 (the ratio of the toner in the developer). To be replenished.

Thereafter, the amount of the developer carried on the first developing roller 81 is adjusted to an appropriate amount at the position of the doctor blade 85, and then reaches a position facing the photosensitive drum 2 (developing area). Further, the developer that has passed through the facing position moves from the first developing roller 81 to the second developing roller 82 and then reaches a position facing the photosensitive drum 2 (which is a second developing area). The toner in the developer adheres to the electrostatic latent image formed on the surface of the photosensitive drum 2 at the facing position.
Thus, the developing process by the developing device 8 is completed.

Hereinafter, a characteristic configuration of the developing device 8 according to the first embodiment will be described in detail.
As shown in FIGS. 2 and 3, the inlet seal 87 as a flexible member is along the longitudinal direction of the opening 80 (the direction perpendicular to the plane of FIG. 2 and the direction of the arrow in FIG. 3). , And a case 86 (installed on the upstream side of the first developing roller 81).
Specifically, the inlet seal 87 has a thickness of about 0.1 mm and is made of polyurethane rubber. The inlet seal 87 is affixed to the case 86 with a double-sided tape with one side in the short direction as a support end, and abuts against the photosensitive drum 2 with the other side in the short side as a free end (protrusion). . Referring to FIG. 2, the inlet seal 87 is set so as to bite about 2 mm with respect to a virtual line indicating the surface of the photosensitive drum 2.

  4A, in the apparatus main body 1 to which the photosensitive drum 2 is mounted, the inlet seal 87 is bent and comes into contact with the rotation of the photosensitive drum 2. As a result, the gap between the opening 80 of the developing device 8 and the photosensitive drum 2 is sealed, and toner scattering in the opening 80 is suppressed. 4B and 4C are views showing a state in which the inlet seal 87 is turned up and in contact with the photosensitive drum 2. FIG. When the inlet seal 87 is turned up as described above, a gap is formed between the opening 80 and the photosensitive drum 2, and toner scattering occurs.

Referring to FIG. 3, side seal 101 as a third flexible member is attached to both ends of opening 80 in the longitudinal direction.
Specifically, the side seal 101 has a thickness of about 0.1 mm and is made of polyurethane rubber. The side seal 101 is attached to the side plate and the upper and lower cases so as to cover the gap between the developing rollers 81 and 82 and the side plate at both ends of the opening 80. Thereby, the problem that the toner (or developer) in the apparatus scatters from both ends of the opening 80 is suppressed.

Further, the auxiliary seal 102 as the second flexible member (sealing member) is attached to both ends of the opening 80 in the longitudinal direction.
Specifically, the auxiliary seal 102 has a thickness of about 0.1 mm and is made of polyurethane rubber. The auxiliary seal 101 is installed so as to cover the protruding portions 87a at both ends in the longitudinal direction of the inlet seal 87 from the photosensitive drum 2 side.

  Specifically, the auxiliary seal 102 has two sticking surfaces 102b and 102c provided with a double-sided tape, and a non-sticking surface 102a not provided with a double-sided tape. One sticking surface 102 b is stuck on the case 86 to which the inlet seal 87 is stuck, and the other sticking surface 102 c is stuck on the side seal 101. Thereby, the protrusion part 87a of the inlet seal 87 is covered with the non-sticking surface 102a. That is, the auxiliary seal 102 is attached with the two positions sandwiching the protruding portion 87a of the inlet seal 87 as the attachment surfaces.

  Thus, the protrusions 87a at both ends in the longitudinal direction of the inlet seal 87 are not directly attached to the auxiliary seal 102, but are brought into contact with the non-sticking surface 102a and the posture thereof is regulated. As a result, when the photosensitive drum 2 is rotated in reverse to remove impurities adhering to the cleaning blade 11a and the blade 30a, or relative to the inlet seal 87 in the longitudinal direction, the photosensitive drum 2 is relatively rotated for maintenance. Even when it is moved, the inlet seal 87 is not turned as shown in FIGS. 4 (B) and 4 (C). By curling the end of the inlet seal 87 in the longitudinal direction, curling of the entire longitudinal direction is restrained.

  Further, since the protruding portion 87a of the inlet seal 87 is not directly attached to the auxiliary seal 102, even when the usage environment changes and the inlet seal 87 expands and contracts, This is a phenomenon in which the flatness of the portion is deteriorated to cause unevenness.). As a result, toner scattering due to the deformation of the inlet seal 87 is suppressed.

  As described above, in the first embodiment, the auxiliary seals 102 for restricting the turning of the inlet seal 87 are provided at both ends in the longitudinal direction of the inlet seal 87 installed in the opening 80 facing the photosensitive drum 2. And installed without sticking to the inlet seal 87. As a result, it is possible to prevent the inlet seal 87 from turning over during maintenance or reverse rotation of the photosensitive drum 2, and to prevent the toner seal from being scattered by preventing deformation of the inlet seal 87 when the usage environment changes.

  In the first embodiment, the present invention is applied to the first developing device 8 including the two developing rollers 81 and 82. However, the second developing device 18 of the one-component developing system described in FIG. The present invention can also be applied. Of course, the present invention can also be applied to a two-component developing system developing device including one developing roller. Also in these cases, the auxiliary seal as the restricting member can prevent the inlet seal from turning up as the flexible member.

Embodiment 2. FIG.
5 and 6, the second embodiment of the present invention will be described in detail.
FIG. 5 is a cross-sectional view showing the vicinity of the end of the developing roller installed in the developing device according to the second embodiment. FIG. 6 is a schematic diagram showing the magnetic force of the main pole in the developing roller. In the developing device of the second embodiment, the position of the auxiliary seal 102 with respect to the magnet 81a provided in the developing roller 81 is limited, and the peak magnetic force of the main pole formed on the developing roller 81 is limited. This is different from that of the first embodiment.

  As shown in FIG. 5, the first developing roller 81 includes a magnet 81a fixed inside, a sleeve 81b rotating around the magnet 81a, and the like. A plurality of magnetic poles (pumping pole, transport pole, main pole, agent cutting pole, etc.) are formed on the first developing roller 81 by a magnet 81 a provided in the first developing roller 81. Then, when the sleeve 81b rotates around the magnet 81a forming the plurality of magnetic poles, the developer moves on the developing roller 81 (on the sleeve 81b) with the rotation. Although not shown, the second developing roller 82 is also composed of a magnet, a sleeve, and the like, like the first developing roller 81.

A broken line G1 in FIG. 6 indicates a main pole (a magnetic pole formed in a developing region facing the photosensitive drum 2) in the first developing roller 81. The broken line H1 indicates the peak magnetic force in the normal direction (the direction facing the photosensitive drum 2) in the main pole of the first developing roller 81. Similarly, a broken line G <b> 2 in FIG. 6 indicates a main pole in the second developing roller 82. A broken line H <b> 2 indicates the peak magnetic force in the normal direction at the main pole of the second developing roller 82.
Here, the main poles G1 and G2 of the developing rollers 81 and 82 cause the developer G carried on the developing rollers 81 and 82 to rise, and the toner in the developer becomes a latent image on the photosensitive drum 2. It is a magnetic pole for making it adhere.

  Also in the second embodiment, as in the first embodiment, the auxiliary seal that restricts the turn-up of the inlet seal 87 at both longitudinal ends of the inlet seal 87 installed in the opening 80 facing the photosensitive drum 2. 102 is installed without sticking to the inlet seal 87.

  Furthermore, in the second embodiment, as shown in FIG. 5, the auxiliary seal 102 as the second flexible member is 4 in the longitudinal direction (the rotation axis direction of the developing roller 81) with respect to the magnet 81a. It is set apart by ± 1 mm. In other words, the distance D between the end of the magnet 81a of the developing roller 81 and the end of the auxiliary seal 102 is set to be 4 ± 1 mm.

Thereby, the occurrence of toner scattering and developer scattering in the developing device 8 can be reliably reduced.
Here, the above-mentioned range of the distance D (D = 4 ± 1 mm) is an optimum value obtained as a result of repeated experiments by the inventor of the present application. Specifically, in the region of the inlet seal 87 covered with the auxiliary seal 102, smooth deformation (a minute undulation, hereinafter referred to as a “small undulation portion” as appropriate) occurs. When the minute waved portion of the inlet seal 87 is too close to the magnet 81a (D <3 mm), the developer carried on the developing roller 81 is kicked by the minute waved portion and the developer scatters. Has been confirmed to occur. On the other hand, if the minute waved portion of the inlet seal 87 is too far from the magnet 81a (D> 5 mm), the sealing performance by the auxiliary seal 102 is reduced and toner scattering occurs. confirmed.

  Further, in the second embodiment, as shown in FIG. 6, the normal direction of the main poles G1 and G2 at both ends in the longitudinal direction of the magnet 81a (the positions of the cross section XX in FIG. 5). The peak magnetic forces H1 and H2 are set to be 45 to 60 mT.

Thereby, the occurrence of toner scattering and developer scattering in the developing device 8 can be reliably reduced.
Here, the above-described ranges of the peak magnetic forces H1 and H2 (H1, H2 = 45 to 60 mT) are optimum values obtained as a result of repeated experiments by the present inventor. Specifically, it has been confirmed that, at both ends in the longitudinal direction of the magnet 81a, developer scattering occurs when the peak magnetic forces H1 and H2 in the normal direction of the main poles G1 and G2 are out of the above range. .

As described above, also in the second embodiment, as in the first embodiment, the inlet seal 87 is provided at both ends in the longitudinal direction of the inlet seal 87 installed in the opening 80 facing the photosensitive drum 2. The auxiliary seal 102 that restricts turning up is installed without sticking to the inlet seal 87. As a result, it is possible to prevent the inlet seal 87 from turning over during maintenance or reverse rotation of the photosensitive drum 2, and to prevent the toner seal from being scattered by preventing deformation of the inlet seal 87 when the usage environment changes.
In particular, in the second embodiment, the position of the auxiliary seal 102 with respect to the magnet 81a provided in the developing roller 81 is optimized, and the peak magnetic force (both ends in the longitudinal direction) of the main pole formed on the developing roller 81 is optimized. The toner scattering and the developer scattering can be further suppressed.

  It should be noted that the present invention is not limited to the above-described embodiments, and within the scope of the technical idea of the present invention, the above-described embodiments can be modified as appropriate in addition to those suggested in the above-described embodiments. Is clear. Further, the number, position, shape, and the like of the constituent members are not limited to the above-described embodiments, and the number, position, shape, and the like that are suitable for implementing the present invention can be used.

1 is a configuration diagram illustrating an image forming apparatus according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view showing a developing device installed in the image forming apparatus of FIG. 1. FIG. 3 is a perspective view showing the vicinity of an end in a longitudinal direction of the developing device of FIG. 2. It is the schematic which shows the contact state of the flexible member with respect to an image carrier. It is sectional drawing which shows the edge part vicinity of the developing roller installed in the developing device in Embodiment 2 of this invention. FIG. 6 is a schematic diagram showing the magnetic force of the main pole in the developing roller of FIG. 5.

Explanation of symbols

1 image forming apparatus body (apparatus body), 2 photosensitive drum (image carrier),
3 First charging unit, 4 Exposure unit, 6 Second charging unit, 7 LED array,
8 First developing device 9 Toner replenishing unit 10 Transfer unit
11 Cleaning section, 11a Cleaning blade, 12 Static elimination section,
18 Second developing device, 20 Document reading unit, 21 CCD,
26 registration roller pair, 27 transfer belt, 28 fixing unit,
80 opening, 81 first developing roller (developer carrier),
82 second developing roller (developer carrier), 83 paddle roller,
84 stirring roller, 85 doctor blade, 86 case,
87 inlet seal (flexible member), 87a protrusion, 88 stirring plate,
89 Conveying screw, 91 Stirring member, 92 Supply roller,
100 toner concentration sensor, 101 side seal (third flexible member),
102 Auxiliary seal (second flexible member, sealing member),
102a Non-sticking surface, 102b, 102c Sticking surface.

Claims (13)

A developing device for developing a latent image formed on an image carrier,
A flexible member that is installed along the longitudinal direction of the opening facing the image carrier, projects toward the image carrier, and contacts the image carrier;
A regulating member that is installed at the end in the longitudinal direction and regulates turning of the flexible member;
A developing device comprising: The developing device according to claim 1, wherein the regulating member is a second flexible member that covers an end portion in a longitudinal direction of the flexible member from the image carrier side. 3. The second flexible member is attached with two positions sandwiching a protruding portion of the flexible member that protrudes toward the image carrier as an attachment surface. The developing device described. A third flexible member is provided at the longitudinal end of the opening,
The developing device according to claim 3, wherein one of the sticking surfaces is a position on the third flexible member. A case to which the flexible member is attached;
The developing device according to claim 3, wherein one of the attachment surfaces is a position on the case. 6. The developing device according to claim 2, wherein the second flexible member is made of polyurethane rubber. Including one or a plurality of developer carriers that are exposed from the opening toward the image carrier and in which a magnet is provided;
The developing device according to claim 2, wherein the second flexible member is disposed 4 ± 1 mm away from the magnet in the longitudinal direction. The developing device according to claim 7, wherein the magnet is formed so that a peak magnetic force in a direction facing the image carrier is 45 to 60 mT at an end in the longitudinal direction. A developer carrier or a plurality of developer carriers that are exposed from the opening toward the image carrier and are rotatably supported;
The developing device according to claim 1, wherein the flexible member is installed on the upstream side in the rotation direction of the developer carrier in the opening. The developing device according to claim 1, wherein the flexible member is made of polyurethane rubber. The developing device according to claim 1, wherein the developing device is configured to be detachable from the main body of the image forming apparatus. 12. An image forming apparatus comprising the developing device according to claim 1 and the image carrier in an image forming apparatus main body. The image forming apparatus according to claim 12, wherein the image carrier is configured to be detachable from the main body of the image forming apparatus with the longitudinal direction as an attaching / detaching direction.

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