JP5998108B2 - Developing device and image forming apparatus - Google Patents

Description

  The present invention relates to a developing device that forms a toner image by supplying toner toward an electrostatic latent image formed on a peripheral surface of a photosensitive drum by an electrophotographic method, and more particularly to an image forming apparatus including the developing device. The present invention relates to a technology for regulating the amount of toner on a sleeve peripheral surface.

  In an electrophotographic image forming apparatus, toner is supplied from a developing device to an electrostatic latent image formed on the surface of a photosensitive drum to form a toner image. This developing device has a developing roller composed of a magnet roller and a developing sleeve, forms a toner layer on the peripheral surface of the developing sleeve, and supplies toner from the developing sleeve to the surface of the photosensitive drum. As such a developing device, there is a device that supplies a stable amount of toner to the surface of the photosensitive drum with a constant amount of toner on the circumferential surface of the developing sleeve by a regulating blade (blade) to which a magnetic material is attached.

  In the case of the developing device described above, even if the toner layer thickness at the central portion in the longitudinal direction of the peripheral surface of the developing sleeve is a predetermined toner layer thickness, the toner regulating force is weakened at the end side, the toner layer thickness is increased, and the toner layer is disturbed. Is likely to occur. In view of this, in order to further stabilize the amount of toner on the circumferential surface of the developing sleeve, Patent Document 1 discloses the magnetic force at both ends of the magnetic body attached to the regulating blade in the rotational axis direction. A developing device set higher than the central portion of the is shown. Patent Document 2 discloses a developing device in which a height dimension of the magnetic body attached to a regulating blade portion facing both ends in the rotation axis direction of the developing sleeve is set lower than a central portion in the rotation axis direction. It is shown. Further, Patent Document 3 discloses a developing device in which the distance between the magnetic body and the circumferential surface of the developing sleeve at both ends in the rotation axis direction is set smaller than the central portion in the rotation axis direction.

  In the developing devices as disclosed in Patent Documents 1 to 3, both ends of the developing sleeve in the rotation axis direction are further suppressed in order to prevent the toner on the circumferential surface of the developing sleeve from moving to the rotation axis direction end. In addition, a seal member may be provided to face the peripheral surface of the developing sleeve.

JP 2011-150122 A JP 2006-317666 A JP 2011-150123 A

When the seal member is provided on the developing sleeve as described above, (1) the gap between the end of the magnetic body and the seal member is provided with a gap allowing for the dimensional tolerance of both, and the magnetic body is attached to the regulating blade, or (2) Interference between the end of the magnetic body and the seal member in the direction of the rotation axis by dividing the magnetic body and providing a gap between the members as two members extending in the direction of the rotation axis and attaching to the regulating blade This prevents the assembly failure of both members. However, in the technique for preventing the assembly failure by the gap as described above, since the magnetic material does not exist in the gap portion, the magnetic flux density in the gap portion is lowered, and the toner regulating force is weakened. For this reason, the toner regulating force is not constant at each position in the rotation axis direction, and the height of the toner layer becomes non-uniform at each position in the rotation axis direction, so that development failure and toner scattering are likely to occur. Further, by disposing the gap portion outside the image forming area in the rotation axis direction of the developing sleeve, image formation can be performed while avoiding the toner scattering, but in this case, the apparatus becomes large in the rotation axis direction of the developing sleeve. .

  The present invention has been made to solve the above-described problems, and prevents insufficient development of toner and toner scattering without increasing the size of the apparatus, thereby suppressing poor development and toner scattering, and poor assembly in relation to the seal member. It is an object of the present invention to make it possible to easily assemble a magnetic body as a magnetic body to a regulating blade without causing the above.

A developing device according to an aspect of the present invention includes a magnet roller having a plurality of magnetic poles in the circumferential direction, and a roller-shaped developing sleeve that is externally mounted on the magnet roller, and supplies the toner to the photosensitive drum. When,
A regulating blade that extends in the direction of the rotation axis of the developing sleeve and is disposed to face the circumferential surface of the developing sleeve via a gap having a predetermined dimension, and regulates the amount of toner existing on the circumferential surface of the developing sleeve When,
A seal member disposed at both ends of the developing sleeve in the rotational axis direction so as to face the peripheral surface of the developing sleeve and suppressing toner on the peripheral surface from moving to the end in the rotational axis direction;
A magnet body which is provided with a gap and is arranged at least two magnets arranged in parallel in the longitudinal direction of the regulating blade, and is attached to the regulating blade in the longitudinal direction up to the arrangement position of the seal member. Prepared,
The magnet body and the regulating blade in a portion where the magnet face each other with a gap, the ends of at least one of the magnet is not in contact with the regulation blade.

  According to the present invention, when the two magnets are attached to the regulating blade, the positioning with respect to the seal member can be adjusted using the gap. For this reason, it becomes possible to assemble the magnet body to the regulation blade without causing an assembly failure in relation to the seal member.

Furthermore, in the present invention, since the magnet body and the regulating blade are opposed to each other with a gap between the magnets , the end of at least one of the magnets is not in contact with the regulating blade. The decrease in force is suppressed. For this reason, the height of the toner layer on the circumferential surface of the developing sleeve can be made uniform at each position in the rotation axis direction of the developing sleeve, and development failure and toner scattering can be hardly caused.

  In addition, by maintaining the toner regulation force and suppressing development defects and toner scattering, it is possible to arrange the gap portion within the image forming range on the peripheral surface of the developing sleeve, thereby increasing the size of the apparatus. I will not let you.

  As a result, according to the present invention, it is possible to prevent insufficient toner regulating force without increasing the size of the apparatus, to suppress development failure and toner scattering, and to prevent magnetic assembly without causing poor assembly in relation to the seal member. As a result, the magnet body can be assembled to the regulating blade.

1 is a front sectional view showing the structure of an image forming apparatus having a developing device according to an embodiment of the present invention. It is a perspective view which cuts and shows a part of developing device. 3 is a cross-sectional view taken along line AA in FIG. FIG. 4 is a perspective view showing a toner amount adjusting mechanism, a developing roller, and a photosensitive drum portion. FIG. 4 is a plan view showing a toner amount adjusting mechanism, a developing roller, and a photosensitive drum portion. FIG. 5 is a side view of a toner amount adjusting mechanism and a developing roller portion viewed from the direction of arrow A in FIG. 4. FIG. 5 is a side view of a toner amount adjusting mechanism, a developing roller, and a photosensitive drum portion viewed from an arrow B direction in FIG. 4. FIG. 5 is a side view of a toner amount adjusting mechanism and a developing roller portion viewed from an arrow B direction in FIG. 4. It is a figure which shows 1st Embodiment of a magnet body, FIG. 9 (A) is the side view which visually recognized the magnet body attached to the control blade from the width direction, FIG.9 (B) is from A direction shown in FIG. FIG. 9C is a side view showing the developing sleeve and the toner amount adjusting mechanism viewed from the B ′ direction shown in FIG. 4. It is a figure which shows the magnet body which concerns on 2nd Embodiment, and is the side view which visually recognized the magnet body attached to the control blade from the width direction. It is a figure which shows the magnet body which concerns on 3rd Embodiment, and is the side view which visually recognized the magnet body attached to the control blade from the width direction. (A) is a side view of the magnet body according to the first embodiment attached to the regulating blade as viewed from the width direction, (B) is a side view of the conventional magnet body attached to the regulation blade as viewed from the width direction, (C) is a figure which shows the magnetic flux density of the control blade front-end | tip part formed with the magnetic field which generate | occur | produces in each part of the longitudinal direction of the magnet body which concerns on 1st Embodiment with a graph. (A) is a side view of the magnet body according to the fourth embodiment attached to the regulating blade as viewed from the width direction, (B) is a side view of the conventional magnet body attached to the regulation blade as viewed from the width direction, (C) is a figure which shows the magnetic flux density of the control blade front-end | tip part formed with the magnetic field which generate | occur | produces in each part of the longitudinal direction of the magnet body which concerns on 4th Embodiment which has a taper shape by a graph. It is the side view which visually recognized from the width direction the magnet body which concerns on 5th Embodiment attached to the control blade. FIG. 9 is a diagram illustrating another embodiment of the toner amount adjusting mechanism, in which (A) is a side view of a regulating blade to which a magnet body is attached viewed from the width direction, and (B) is a development viewed from the A direction shown in FIG. FIG. 5C is a side view showing the sleeve and the toner amount adjusting mechanism, and FIG. 5C is a side view showing the developing sleeve and the toner amount adjusting mechanism viewed from the B ′ direction shown in FIG. 4. (A) is a side view of a magnet body according to another embodiment attached to a regulating blade as viewed from the width direction, (B) is a side view of a conventional magnet body attached to the regulation blade as viewed from the width direction, (C) is a figure which shows the magnetic flux density of the control blade front-end | tip part formed with the magnetic field which generate | occur | produces in each part of the longitudinal direction of the magnet body which concerns on other embodiment with a graph. It is a side view which shows other embodiment of the control blade applied with the toner amount adjustment mechanism which concerns on this embodiment by the side view from the width direction of a control blade. It is a side view which shows other embodiment of the control blade applied with the toner amount adjustment mechanism which concerns on this embodiment by the side view from the width direction of a control blade. It is a side view which shows other embodiment of the control blade applied with the toner amount adjustment mechanism which concerns on this embodiment by the side view from the width direction of a control blade.

  Hereinafter, a developing device and an image forming apparatus including the developing device according to an embodiment of the present disclosure will be described with reference to the drawings. FIG. 1 is a front sectional view showing the structure of an image forming apparatus having a developing device according to an embodiment of the present invention.

  The image forming apparatus 1 according to an embodiment of the present disclosure is a multifunction machine having a plurality of functions such as a copy function, a printer function, a scanner function, and a facsimile function. The image forming apparatus 1 includes an apparatus main body 11 that includes an operation unit 47, an image forming unit 12, a fixing unit 13, a paper feeding unit 14, a document feeding unit 6, a document reading unit 5, and the like.

  When the image forming apparatus 1 performs a document reading operation, the document reading unit 5 optically reads a document fed by the document feeding unit 6 or a document placed on the document placing glass 161, Generate image data. Image data generated by the document reading unit 5 is stored in a built-in HDD or a network-connected computer.

  When the image forming apparatus 1 performs an image forming operation, the image forming unit 12 is supplied from the paper supply unit 14 based on the image data generated by the document reading operation or the image data stored in the built-in HDD. A toner image is formed on a recording paper P as a recording medium to be paper. The image forming units 12M, 12C, 12Y, and 12Bk of the image forming unit 12 include a photosensitive drum 121, a charging device 123, an exposure device 124, a developing device 122, and a primary transfer roller 126, respectively. .

  Each developing device 122 of the image forming units 12M, 12C, 12Y, and 12Bk contains toner for developing an electrostatic latent image. The developing device 122 supplies the toner to the surface of the photosensitive drum 121 that has been charged by the charging device 123 and exposed by the exposure device 124.

  When performing color printing, the magenta image forming unit 12M, the cyan image forming unit 12C, the yellow image forming unit 12Y, and the black image forming unit 12Bk of the image forming unit 12 each receive image data. A toner image is formed on the photosensitive drum 121 by charging, exposure, and development processes based on the image composed of each color component, and the toner image is driven by the primary transfer roller 126 by the driving roller 125a and the driven roller 125b. The image is transferred onto the intermediate transfer belt 125 that is stretched around the belt.

  The intermediate transfer belt 125 is driven by a driving roller 125 a in a state where an image carrying surface on which a toner image is transferred is set on the outer peripheral surface thereof and in contact with the peripheral surface of the photosensitive drum 121. The intermediate transfer belt 125 travels endlessly between the driving roller 125a and the driven roller 125b while being synchronized with each photosensitive drum 121.

  The toner images of the respective colors transferred onto the intermediate transfer belt 125 are superimposed on the intermediate transfer belt 125 with the transfer timing adjusted to become a color toner image. The secondary transfer roller 210 conveys the color toner image formed on the surface of the intermediate transfer belt 125 from the sheet feeding unit 14 through the conveyance path 190 at the nip N between the intermediate transfer belt 125 and the driving roller 125a. The recording sheet P is transferred. Thereafter, the fixing unit 13 fixes the toner image on the recording paper P to the recording paper P by thermocompression bonding. The recording paper P on which the color image has been formed after completion of the fixing process is discharged to a discharge tray 151.

  Next, the configuration of the developing device 122 will be described. FIG. 2 is a perspective view showing the developing device 122 with a part thereof cut away. 3 is a cross-sectional view taken along line AA in FIG. 2 and 3, the XX direction is referred to as the left-right direction, the YY direction is referred to as the front-rear direction, and in particular, the -X direction is referred to as the left, the + X direction is referred to as the right, the -Y direction is referred to as the front, and the + Y direction is referred to as the rear. .

  As shown in FIGS. 2 and 3, the developing device 122 includes a first spiral feeder 51, a second spiral feeder 52, and a developing roller 53 in a housing 58.

  The first spiral feeder 51 conveys the toner supplied from the toner container 59 backward while stirring. The second spiral feeder 52 conveys the toner delivered from the first spiral feeder 51 toward the front. The developing roller 53 receives the toner conveyed by the second spiral feeder 52 and supplies it to the latent image area on the peripheral surface of the photosensitive drum 121.

  The developing roller 53 includes a magnet roller 531 and a developing sleeve 532. The developing sleeve 532 is externally mounted on the magnet roller 531. The developing sleeve 532 is rotatably supported by the housing 58 at a position adjacent to the surface of the photosensitive drum 121 and the second spiral feeder 52. The developing sleeve 532 is formed in a cylindrical shape with a nonmagnetic material such as aluminum, and the surface roughness Rz is finished to, for example, 10 mμ or less.

  The magnet roller 531 is a permanent magnet fixed in the developing sleeve 532. The magnet roller 531 has a plurality of magnetic poles in which S poles and N poles are alternately arranged in the circumferential direction, and generates a magnetic field toward the developing sleeve 532. Further, the developing roller 53 is exposed from the opening of the housing 58 and faces the photosensitive drum 121 that is an image carrier at a predetermined interval. This opposed area is a developing area for supplying the toner carried on the developing sleeve 532 toward the photosensitive drum 121. A developing bias in which alternating current is superimposed on direct current is applied to the developing sleeve 532 in order to supply toner to the photosensitive drum 121.

  For example, the magnetic pole S <b> 1 is disposed at a position facing the regulating blade 81 of the magnet roller 531. In addition, a magnetic pole N2 is disposed at a position facing the developing area, and a magnetic pole S2 is disposed at a toner circulation area where residual toner after development is conveyed, and further at a position facing the second spiral feeder 52. Is provided with a magnetic pole N1.

  The peripheral surface of the developing sleeve 532 carries the toner supplied from the toner container 59 through the toner supply port 581 and moved from the first spiral feeder 51 and the second spiral feeder 52 by the magnetic force of the magnet roller 531. The The first spiral feeder 51 is supplied with toner from a toner container (not shown) through the toner supply port 581 of the housing 58.

  The regulating blade 81 regulates the toner carried on the circumferential surface of the developing sleeve 532 to a predetermined layer thickness, and sets a predetermined interval between the developing sleeve 532 and the surface of the developing sleeve 532. It is supported by the housing 58 at a distance.

  The toner carried on the peripheral surface of the developing sleeve 532 is regulated to a predetermined layer thickness by the regulating blade 81, and is conveyed toward the developing region by the rotation of the developing sleeve 532 (rotation in the arrow direction in FIG. 2). Is done. When a developing bias is applied to the developing sleeve 532, a potential difference is generated between the developing sleeve 532 and the photosensitive drum 121 in the developing region, and the toner on the developing sleeve 532 moves to the photosensitive drum 121, and the photosensitive drum 121 The electrostatic latent image on the body drum 121 is developed into a toner image.

  A toner amount adjusting mechanism 80 including the regulating blade 81 is disposed at a position facing the peripheral surface of the developing sleeve 532.

FIG. 4 is a perspective view illustrating the toner amount adjusting mechanism 80, the developing roller 53, and the photosensitive drum 121. FIG. 5 is a plan view showing the toner amount adjusting mechanism 80, the developing roller 53, and the photosensitive drum 121. 6 is a side view of the toner amount adjusting mechanism 80, the developing roller 53, and the photosensitive drum 121 viewed from the direction of arrow A in FIG. 7 and 8 are side views of the toner amount adjusting mechanism 80, the developing roller 53, and the photosensitive drum 121 viewed from the direction of arrow B in FIG. 4 to 8, the direction display by X and Y is the same as in FIG. 2 (X is the left-right direction (-X: leftward, +: X rightward), Y is the front-back direction (-Y: forward). , + Y: backward))). Hereinafter, the toner amount adjusting mechanism 80 will be described with reference to FIGS. 4 to 8 and FIGS.

  First, as shown in FIG. 4, the toner amount adjustment mechanism 80 includes a regulation blade 81, a seal member 82, and a magnet body 83.

  The seal member 82 is made of a magnetic member, and is disposed at both ends of the developing sleeve 532 in the rotation axis direction so as to face the peripheral surface of the developing sleeve 532. The seal member 82 prevents the toner on the circumferential surface of the developing sleeve 532 from moving toward the end in the rotation axis direction.

  The magnet body 83 is a member made of, for example, a magnet and generating a magnetic field. The magnet body 83 is attached to the regulating blade 81 in the longitudinal direction up to the position where the seal member 82 is disposed. The magnet body 83 is attached to a side surface of the regulating blade 81 that is upstream in the direction in which the peripheral surface of the developing sleeve 532 rotates. The side edge of the magnet 83 on the developing sleeve 532 side is the same S pole as the magnetic pole S1 of the magnet roller 531 in the developing sleeve 532, and the opposite edge is an N pole.

  The regulating blade 81 rotates toner around the developing sleeve 532 and rotates the circumferential surface of the developing drum 532 to the latent image area 22 on the circumferential surface of the photosensitive drum 121 (area where an electrostatic latent image between two-dot chain lines shown in FIG. 4 is formed). Regulate the volume to prevent oversupply. The regulating blade 81 is provided so as to cross the developing sleeve 532 in the rotation axis direction at a position facing the circumferential surface of the developing sleeve 532. The leading edge portion of the regulation blade 81 forms an edge and faces the circumferential surface of the developing sleeve 532. The leading edge is provided at a predetermined interval from the circumferential surface of the developing sleeve 532.

  The regulation blade 81 is made of a long blade-like member, and is formed of a magnetic material such as stainless steel, for example. As shown in FIG. 8, the tip of the regulating blade 81 on the developing sleeve 532 side is magnetized to a polarity (N pole) opposite to the opposite end of the magnet 83 by the magnetic force of the magnet 83, and the tip of the regulating blade 81 A magnetic field is also formed between the portion and the magnet body 83. Therefore, a magnetic field is formed between the tip of the regulating blade 81 and the developing sleeve 532 by the magnetic pole of the magnet roller 531 and the magnetic pole of the magnet body 83 in the developing roller 53. By these magnetic fields, the toner passes through the gap between the regulating blade 81 and the developing sleeve 532 in a substantially uniform state, and a thin toner layer is formed on the developing sleeve 532.

  In the seal member 82, the toner moves from the circumferential surface of the developing sleeve 532 toward the end thereof until the toner on the circumferential surface of the developing sleeve 532 reaches the position where the regulating blade 81 is disposed. To prevent. The seal member 82 is formed in an arc shape in which the central angle of curvature is set to approximately 180 ° when viewed from the front (viewed from the direction B in FIG. 4). As shown in FIG. 7, the seal member 82 has an upper end that is in contact with and fixed to the right surface side of the regulating blade 81, and a lower end that is supported by a part of the housing 58, so that the circumference of the developing sleeve 532 A separated state having a gap with respect to the surface is secured.

  According to the seal member 82, a magnetic brush is formed between the seal member 82 and the magnet roller 531 housed in the developing sleeve 532 using magnetic lines of force. Since the magnetic brush regulates the movement of the toner toward the end in the rotation axis direction of the developing sleeve 532, the toner is prevented from moving from the peripheral surface of the developing sleeve 532 toward the end.

  As shown in FIG. 6, both end portions of the magnet body 83 in the front-rear direction of the developing sleeve 532 (the left-right direction of the paper surface in FIG. 6) are located up to the position of the side end portion of the seal member 82. The installation position is set.

  Since the magnet 83 and the seal member 82 are attached to the regulating blade 81 in this way, the toner on the peripheral surface of the developing sleeve 532 can be properly supplied to the peripheral surface of the photosensitive drum 121 and the developing sleeve 532 can be supplied. The toner is prevented from being thickened on the peripheral surface of the end portion in the rotation axis direction.

  Next, a first embodiment of the magnet body 83 attached to the restriction blade 81 will be described. FIG. 9 is a view showing a first embodiment of the magnet body 83, FIG. 9A is a side view of the magnet body 83 attached to the regulating blade 81 viewed from the width direction, and FIG. 4 is a side view showing the developing sleeve 532 and the toner amount adjusting mechanism 80 viewed from the A direction, and FIG. 9C is a side view showing the developing sleeve 532 and the toner amount adjusting mechanism 80 viewed from the B ′ direction shown in FIG. FIG.

  In each embodiment described below, the magnet body 83 includes two magnets 831 and 832 arranged in parallel in the longitudinal direction of the regulating blade 81. The magnet body 83 is attached to the regulating blade 81 in the longitudinal direction up to the position where the seal member 82 is disposed. That is, the magnet body 83 is attached to the regulating blade 81 so that the end portion in the longitudinal direction reaches the position of the side portion of the seal member 82.

  The magnet body 83 and the regulating blade 81 are configured such that at least one end portion of the magnets 831 and 832 at a portion where the magnets 831 and 832 face each other with a gap (in this embodiment, the end portion 831a of the magnet 831 and And the regulating blade 81 is formed to be larger than the distance in the longitudinal direction of the regulating blade 81 other than the facing portion.

  In the first embodiment, as shown in FIG. 9A, the magnet body 83 includes magnets 831 and 832 extending in the longitudinal direction. Magnets 831 and 832 are arranged side by side with a gap in the longitudinal direction.

  Here, the longitudinal end 831a of one magnet 831 is formed such that the adhesion surface 831b to the regulating blade 81 is shorter in the longitudinal direction than the opposite surface 831c of the adhesion surface 831b.

  Further, the end 832a in the longitudinal direction of the other magnet 832 is formed such that the adhesive surface 832b to the regulating blade 81 is longer in the longitudinal direction than the opposite surface 832c of the adhesive surface 832b.

  Furthermore, the magnets 831 and 832 have the end portions 831a and 832a in the thickness direction of the magnets 831 and 832 while the end portions 831a and 832a are opposed to each other and have a gap between the end portions 831a and 832a. It arrange | positions so that some 832a may mutually overlap.

  9B, the end portion 831d of the magnet 831 and the end portion 832d of the magnet 832 in the longitudinal direction of the seal member 82 provided at both ends of the developing sleeve 532 in the rotation axis direction, respectively. It is arranged up to a position reaching the side portion 821.

Next, a second embodiment of the magnet body 83 attached to the restriction blade 81 will be described. FIG. 10 is a view showing the magnet body 83 according to the second embodiment, and is a side view of the magnet body 83 attached to the regulating blade 81 viewed from the width direction. Note that configurations not particularly described in the following description are the same as those in the first embodiment.

  As shown in FIG. 10, in the magnet body 83 according to the second embodiment, an end portion 831 a of a magnet 831 that is one of magnets 831 and 832 facing each other in the longitudinal direction has a convex shape, and the other magnet 832. The end portion 832a of the magnet 831a and the end portion 832a are arranged so that the end portions 832a and 832a overlap each other in the thickness direction of the magnets 831 and 832. Has been.

  Furthermore, a third embodiment of the magnet body 83 attached to the restriction blade 81 will be described. FIG. 11 is a view showing the magnet body 83 according to the third embodiment, and is a side view of the magnet body 83 attached to the regulating blade 81 viewed from the width direction. Note that configurations not particularly described in the following description are the same as those in the first embodiment.

  As shown in FIG. 11, in the magnet body 83 according to the third embodiment, the end 831a of the magnet 831 in the longitudinal direction is such that the adhesion surface 831b to the regulating blade 81 is longer than the opposite surface 831c of the adhesion surface 831b. However, the end portion 831a is formed in a staircase shape. In the end portion 831 a, a protruding portion 831 e that protrudes toward the end portion 832 a in the longitudinal direction of the other magnet 832 is formed at a portion on the opposite surface 831 c side in the thickness direction.

  On the other hand, the end 832a in the longitudinal direction of the magnet 832 is formed such that the adhesion surface 832b to the regulating blade 81 is longer in the longitudinal direction than the opposite surface 832c, and the end 832a is formed in a step shape. In the end portion 832a, a protruding portion 832e that protrudes toward the end portion 831a in the longitudinal direction of the magnet 831 is formed at a portion on the adhesive surface 832b side in the thickness direction.

  The magnets 831 and 832 are arranged so that the protruding portions 831e and the protruding portions 832e overlap in the thickness direction of the magnets 831 and 832 while having a gap between the end portions 831a and 832a.

  As shown in the first to third embodiments, the magnet body 83 is composed of the magnets 831 and 832 and is arranged in parallel in the longitudinal direction of the magnet body 83 while having a gap between the end portions 831a and 832a. Then, by positioning the end portion 831d and the end portion 832d to a position reaching the side portion 821 of the seal member 82, when the magnet body 83 is attached to the regulating blade 81, the positioning of the magnet body 83 with respect to the seal member 82 is performed. It is possible to adjust the attachment positions in the longitudinal direction of the magnets 831 and 832 in the regulating blade 81 using the gap between the end portions 831a and 832a. That is, when the magnets 831 and 832 are attached, the end portion 831d and the end portion 832d can be easily and accurately arranged to reach the side portion 821 of the seal member 82 by changing the size of the gap in the longitudinal direction. become. For this reason, when attaching the magnet body 83 to the regulating blade 81, accuracy is not required for positioning with respect to the seal member 82.

  Further, as described above, the magnet body 83 can be disposed in close contact with the seal members 82 at both ends by adjusting the gap between the magnets 831 and 832, thereby preventing developer leakage and toner scattering at the longitudinal ends of the magnet body 83. Is possible.

  In the first to third embodiments, the end 831 a of the magnet 831 and the end 832 a of the magnet 832 are separated from the regulation blade 81. As a result, an effect of raising the magnetic flux density at the end portion 831a and the end portion 832a is generated. By overlapping the end portions 831a and 832a facing each other, the magnetic flux density in the gap between the magnets 831 and 832 is increased. Can be suppressed.

  In this way, the magnetic flux density does not decrease to the level of developer leakage at the end portion in the length direction of the magnet body 83, and the magnetic flux density can be maintained up to the end portion as compared with the prior art. Widely secured in the vertical direction. For this reason, if the image effective area is the same, the developing device 122 can be configured smaller. However, although the portion where the magnetic flux density falls below the lower limit affecting the image cannot be completely eliminated, the end portion 831a of the magnet 831 and the end portion 832a of the magnet 832 are arranged so that this portion is outside the image forming area. It is necessary to arrange the portion where the two are opposed to each other at the end in the longitudinal direction of the magnet body 83.

  FIG. 12 is a graph showing the magnetic flux density at the tip of the regulating blade formed by the magnetic field generated at each part in the longitudinal direction of the magnet body 83 according to the first embodiment. In FIG. 12C, the magnetic flux density at the tip of the regulating blade formed by the magnet body 83 according to the first embodiment is shown by a solid line, and the magnetic flux at the tip of the regulating blade formed by the conventional magnet body 83 is shown. The density is indicated by a broken line.

  A toner amount adjusting mechanism 80 ′ having a conventional magnet body 83 ′ that includes two magnets 831 ′ and 832 ′ and has no overlapping portion in the thickness direction at end portions 831a ′ and 832a ′ facing the other magnet member. In this case, as indicated by a broken line in FIG. 12C, the magnetic force is reduced in a region where no magnet body exists in the longitudinal direction (the rotation axis direction of the developing sleeve 532).

  However, in the case of the toner amount adjusting mechanism 80 including the magnet body 83 according to the first embodiment, as indicated by a solid line in FIG. 12C, the position serving as a joint between the magnets 831 and 832 in the longitudinal direction, that is, At the position where the end portion 831a and the end portion 832a face each other with the gap, the end portions 831a and 832a are arranged so that the end portions 831a and 832a overlap each other in the thickness direction. Smaller than the magnetic force produced by the toner amount adjusting mechanism. Similarly, in the case of the toner amount adjusting mechanism 80 including the magnet body 83 according to the second and third embodiments, it is possible to suppress a decrease in magnetic force at the position.

  Subsequently, a fourth embodiment of the magnet body 83 will be described. FIG. 13A is a view showing a magnet body 83 according to the fourth embodiment, FIG. 13B is a view showing a conventional magnet body, and FIG. 13C is generated at each part in the longitudinal direction of the magnet body 83 according to the fourth embodiment. The magnetic flux density of the front-end | tip part of the control blade formed with the magnetic field to show is shown with a graph.

  As shown in FIG. 13A, the magnet body 83 according to the fourth embodiment includes magnets 831 and 832 extending in the longitudinal direction. Magnets 831 and 832 are arranged side by side with a gap in the longitudinal direction.

  Here, the longitudinal ends 831a and 832a of both the magnets 831 and 832 are such that the adhesive surfaces 831b and 832b to the regulating blade 81 are longer in the longitudinal direction than the opposite surfaces 831c and 832c of the adhesive surfaces 831b and 832b. The dimensions are short.

  Further, the magnets 831 and 832 are arranged with a gap between the end 831a and the end 832a with the end 831a and the end 832a facing each other.

  As in the first to third embodiments, the end portion 831d of the magnet 831 and the end portion 832d of the magnet 832 are side portions of the seal member 82 provided at both ends in the rotation axis direction of the developing sleeve 532, respectively. It is arranged up to a position reaching 821.

According to the magnet body 83 according to the fourth embodiment, as in the case of the magnet body 83 according to the first to third embodiments, the position serving as a joint between the magnets 831 and 832, that is, the gap is provided. In the position where the end portions 831a and 832a face each other, in addition to the effect that the decrease in magnetic force is smaller than that of the conventional toner amount adjusting mechanism, the following effect is obtained.

  In the case of the magnet body 83 according to the fourth embodiment, the magnet body 83 and the magnet body 831 are disposed at positions where the end portion 831a of the magnet 831 and the end portion 832a of the magnet 832 are disposed in the longitudinal direction of the magnet 831 (the rotation axis direction of the developing sleeve 532). The magnetic field generated at the end in the longitudinal direction of the regulating blade 81 is that the magnet body 83 and the regulating blade 81 are located at a distance, so that the magnetic field generated between the magnet body 83 and the regulating blade 81 is longitudinal. It becomes larger than the magnetic field generated at the center in the direction.

  For this reason, as shown by a solid line in FIG. 13C, the magnetic flux density is higher than the magnetic flux density at the central portion in the longitudinal direction at the position where the end portion 831a is disposed in the longitudinal direction, and between the magnet 831 and the magnet 832. Before the magnetic flux density at the gap portion decreases to the image influence lower limit, the magnetic flux density can be made higher than the magnetic flux density at the central portion in the longitudinal direction at the arrangement position of the end portion 832a in the longitudinal direction. .

  Accordingly, as shown in FIG. 13C, according to the magnet body 83 according to the fourth embodiment, the magnetic flux density can be maintained at the image influence lower limit or more in the entire longitudinal direction of the magnet body 83. It is possible to arrange the void in the image area. For this reason, according to the magnet body 83 according to the fourth embodiment, the image effective range in the longitudinal direction that can be used for image formation (the magnetic flux density exceeds the lower limit of the end developer mole shown in FIG. 13C). In addition, it is possible to make the area larger than the lower limit of the image influence than in the past.

  In FIG. 13C, the image influence lower limit indicates a lower limit value that does not cause an image defect if the magnetic flux density is equal to or higher than this value. The lower limit of the end developer leakage is a value at which the developer leakage may occur from the end when the magnetic flux density is less than this value.

  Next, a fifth embodiment of the magnet body 83 will be described. 14A is a view showing a magnet body 83 according to the fifth embodiment, FIG. 14B is a view showing a conventional magnet body, and FIG. 14C is generated at each part in the longitudinal direction of the magnet body 83 according to the fifth embodiment. The magnetic flux density of the front-end | tip part of the control blade formed with the magnetic field to show is shown with a graph.

  As shown in FIG. 14A, the magnet body 83 according to the fifth embodiment also includes magnets 831 and 832 extending in the longitudinal direction.

  Here, the longitudinal end 831a of the magnet 831 is formed such that the adhesive surface 831b to the regulating blade 81 is shorter in the longitudinal direction than the opposite surface 831c of the adhesive surface 831b.

In the other magnet 832 , the adhesion surface 832 b to the regulating blade 81 and the opposite surface 832 c are formed to have a dimension in the longitudinal direction shorter than the central portion in the thickness direction of the magnet 832 . The end portions 831a and the end portions 832b of the magnets 831 and 832 are disposed with a gap between them.

According to the magnet body 83 according to the fifth embodiment, as shown in FIG. 13C , the same effect as the fourth embodiment can be obtained with respect to the suppression of the decrease in the magnetic flux density. Since the end portion 831a and the end portion 832a can be arranged so as to overlap in the thickness direction in the longitudinal direction, the magnet body 83 according to FIG. In order to eliminate the variation in size, the effect that the range in which the positions of the magnets 831 and 832 can be adjusted in the length direction is wider than that of the magnet body 83 according to the fourth embodiment is obtained. Also in the case of the fourth and fifth embodiments, the end portion 831a of the magnet 831 and the end portion 832a of the magnet 832 are separated from the regulating blade 81, so that the magnetic flux in the end portion 831a and the end portion 832a portion. A density lifting effect is produced, and the magnetic flux density in the gap between the magnets 831 and 832 can be suppressed by overlapping the end 831a and the end 832a facing each other. And in the case of 4th and 5th embodiment, since it becomes possible to maintain more than the minimum which affects an image in the whole longitudinal direction of the magnet body 83, the edge part 831a of the magnet 831 and the edge part 832a of the magnet 832 oppose. It is possible to arrange the portion to be within the image forming area.

  Next, another embodiment of the toner amount adjusting mechanism 80 will be described. 15A and 15B are diagrams showing another embodiment of the toner amount adjusting mechanism 80. FIG. 15A is a side view of the regulating blade 81 to which the magnet body 83 is attached as viewed from the width direction, and FIG. 4 is a side view showing the developing sleeve 532 and the toner amount adjusting mechanism 80 viewed from the A direction shown in FIG. 4, and FIG. 15C shows the developing sleeve 532 and the toner amount adjusting mechanism 80 viewed from the B ′ direction shown in FIG. It is a side view.

  In the toner amount adjusting mechanism 80 according to the present embodiment, the magnet body 83 includes two magnets 831 and 832 arranged in parallel in the longitudinal direction of the regulating blade 81 as shown in FIGS. The magnet body 83 is attached to the restriction blade 81 in the longitudinal direction up to the position where the seal member 82 is disposed.

  In the toner amount adjusting mechanism 80 according to the present embodiment, the regulating blade 81 is a part of the facing surface 810 that faces the magnet body 83 at a portion where the end portions 831a and 832a of the magnets 831 and 832 of the magnet body 83 face each other. However, the shape of the regulating blade 81 has a notch 815 that is partially cut away in the thickness direction. Further, the notch 815 is preferably filled with a nonmagnetic member 816. In this embodiment, it is assumed that the nonmagnetic member 816 is filled. The notch 815 is formed in a region extending over both ends 831 a and 832 a in the length direction of the regulating blade 81.

  Thus, since the magnet body 83 has the notch 815, the distance from the regulating blade 81 to the end 831a and the end 832a of the magnet 831 and 832 at the portion where the magnets 831 and 832 face each other. However, it is formed larger than the said distance in the center part of a longitudinal direction.

  In the present embodiment, as shown in FIG. 15B, the notch 815 is provided at a part of the position facing the end portions 831a and 832a in the width direction of the regulating blade 81. However, it is sufficient that the notch portion 815 is formed in a part of a region facing the end portions 831a and 832a in the width direction of the regulating blade 81. The region where the notch 815 is formed in the width direction may be a part or all of a portion facing the end portions 831a and 832a in the width direction.

  FIG. 16C is a graph showing the magnetic flux density at the tip of the regulating blade formed by the magnetic field generated in each part in the longitudinal direction of the magnet body 83 by the toner amount adjusting mechanism 80 according to another embodiment. In FIG. 16C, the magnetic flux density generated by the magnet body 83 of the toner amount adjusting mechanism 80 according to the present embodiment is indicated by a solid line, and the magnetic flux density generated by the conventional magnet body 83 is indicated by a broken line. This will be described with reference to FIG.

  As shown by a broken line in FIG. 16C, in the case of the toner amount adjusting mechanism 80 having a conventional regulating blade (FIG. 16B) that does not have the notch 815 at the position where the two magnets 831 and 832 face each other. In a region where no magnet is present in the longitudinal direction (rotational axis direction of the developing sleeve 532), the magnetic force is reduced.

However, in the case of the toner amount adjusting mechanism 80 including the regulating blade 81 having the notch portion 815 shown in FIG. 16A, the magnets 831 and 832 are arranged in the longitudinal direction as shown by a solid line in FIG. At the joint position, that is, at the position where the end portions 831a and 832a are opposed to each other with the gap, the distance between the magnet body 83 and the regulating blade 81 is determined by the presence of the notch portion 815. Since the magnetic force generated by the magnet body 83 due to separation in the thickness direction increases, the decrease in the magnetic force in the gap portion where the magnet body 83 does not exist is smaller than that of the conventional toner amount adjusting mechanism.

For this reason, as shown in FIG. 16, according to the magnet body 83, the regulation blade 81 has the notch portion 815. Therefore, in this embodiment, the magnetic flux density is the image influence lower limit in the entire longitudinal direction of the magnet body 83. Since the above can be maintained, it becomes possible to arrange | position the space | gap part of the magnet body 83 in an image area. Therefore, according to the magnet 83, the effective image range in the longitudinal direction that can be used for image formation (the magnetic flux density exceeds the lower limit of the end developer mole shown in FIG. 16, and
It is possible to make the area above the image influence lower limit wider than before.

  Next, another embodiment of the regulation blade 81 applied in the toner amount adjusting mechanism 80 according to this embodiment will be described. FIGS. 17-19 is a side view which shows other embodiment of the control blade 81 by the side view from the width direction.

  The regulating blade 81 according to the other embodiment chamfers the corner portion of the cutout portion 815 in the side view shown in FIG. 16A, and the cutout portion 815 forms the inner side surface portion 811a as shown in FIG. The shape is an inclined surface. When the notch portion 815 has the inner side surface portion 811a, the distance between the regulating blade 81 and the magnet body 83 gradually changes in the longitudinal direction in the inner side surface portion 811a portion, so that the magnetic force in the longitudinal direction in the inner side surface portion 811a portion is steep. Changes can be avoided.

  In addition, the regulating blade 81 according to the third embodiment shown in FIG. 18 has a corner portion of the notch 815 in the side view shown in FIG. In this way, by making the corner portion into an R shape, it is possible to avoid a sharp change in the magnetic force in the longitudinal direction of the notch 815 portion.

  Furthermore, further chamfering or blending may be performed on the notch 815 that has been chamfered or blended as described above. FIG. 19 shows a regulating blade 81 that is further blended at the corner of the notch 815 shown in FIG. According to this, it is possible to further moderate the amount of change in magnetic force in the longitudinal direction at the notch 815 portion.

  As described above, according to the regulation blade 81 and the magnet body 83 having the above-described shapes, the magnet body 83 is the two magnets 831 and 832 arranged in parallel in the longitudinal direction of the regulation blade 81 with a gap. By attaching to the blade 81 in the longitudinal direction up to the position where the seal member 82 is disposed, the magnet body 83 can be assembled to the regulating blade 81 without causing an improper assembly in relation to the seal member 82. It becomes.

  Furthermore, in the magnet body 83 and the regulating blade 81, the distance between at least one end of the magnets 831 and 832 and the regulating blade 81 in the portion where the magnets 831 and 832 face each other with a gap is in the longitudinal direction. It is formed to be larger than the distance other than the facing portion, thereby increasing the magnetic force generated in the portion. For this reason, a decrease in the toner regulating force at the portion is suppressed, and the height of the toner layer on the circumferential surface of the developing sleeve 532 can be made uniform at each position in the rotation axis direction of the developing sleeve 532, so that toner scattering is less likely to occur. be able to. In addition, the effective image range in the longitudinal direction that can be used for image formation can be made wider than before.

  In addition, by maintaining the toner regulating force and suppressing the toner scattering in this way, the gap portion is disposed close to the image forming area on the circumferential surface of the developing sleeve 532, and further, in the image forming area. Since it can be arranged, the developing device 122 is not enlarged.

  As a result, according to each of the embodiments described above, the magnet body 83 is attached to the regulating blade 81 without causing insufficient assembly of the toner in the relationship with the seal member 82 while preventing toner scattering by preventing insufficient toner regulation. Can be assembled.

  The present invention is not limited to the configuration of the above embodiment, and various modifications can be made. The configurations and processes shown in the above embodiments using FIGS. 1 to 19 are only one embodiment of the present invention, and the configurations and processes of the present invention are not limited thereto.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 122 Developing apparatus 53 Developing roller 531 Magnet roller 532 Developing sleeve 80 Toner amount adjusting mechanism 82 Seal member 81 Restricting blade 811 Notch 815 Notch 816 Nonmagnetic member 83 Magnet body 831 832 Magnet member 831a End 831b Adhesive surface 831c Opposite surface 831d End portion 831e Protruding portion 832a End portion 832b Adhesive surface 832c Opposite surface 832d End portion 832e Protruding portion

Claims (9)

A developing roller that has a magnet roller having a plurality of magnetic poles in the circumferential direction, and a roller-shaped developing sleeve that is sheathed by the magnet roller, and supplies toner to the photosensitive drum;
A regulating blade that extends in the direction of the rotation axis of the developing sleeve and is disposed to face the circumferential surface of the developing sleeve via a gap having a predetermined dimension, and regulates the amount of toner existing on the circumferential surface of the developing sleeve When,
A seal member disposed at both ends of the developing sleeve in the rotational axis direction so as to face the peripheral surface of the developing sleeve and suppressing toner on the peripheral surface from moving to the end in the rotational axis direction;
A magnet body which is provided with a gap and is arranged at least two magnets arranged in parallel in the longitudinal direction of the regulating blade, and is attached to the regulating blade in the longitudinal direction up to the arrangement position of the seal member. Prepared,
The magnet body and the regulating blade in a portion where the magnet face each other with a gap, the ends of at least one of the magnet is not in contact with the regulation blade developing device. The magnet body, the adhesive surface to the regulating blade definitive to the magnet of the one is, than the opposite surface of the adhesive surface dimensions in the longitudinal direction is shorter, the regulations definitive to the other of the magnet The bonding surface to the blade is formed to have a longer dimension in the longitudinal direction than the opposite surface of the bonding surface, and the end portions of the magnets are arranged to overlap each other with a gap between them. The developing device according to claim 1.   The magnet body has, in the longitudinal direction, one of the end portions of the magnet facing each other has a convex shape, the other is a concave shape, and the end portions of the magnets have a gap between them. The developing device according to claim 1, wherein the developing device is disposed so as to overlap in the thickness direction. The magnet body, in a portion where the magnet face each other with a gap, the ends of both of said magnets is not in contact with the regulation blade, to the regulating blade definitive to the magnets of the both The bonding surface is formed so that the dimension in the longitudinal direction is shorter than the opposite surface of the bonding surface, and the end portions of the magnets are arranged with a gap between them. Development device. The magnet body, the adhesive surface to the regulating blade definitive to one of the magnets is, than the opposite surface of the adhesive surface dimensions in the longitudinal direction is shorter, the regulating blade definitive to the other of the magnet 2. The adhesive surface and the opposite surface thereof are formed so that the dimension in the longitudinal direction is shorter than the central portion in the thickness direction, and the end portions of the magnets are arranged with a gap between them. The developing device according to 1.   2. The developing device according to claim 1, wherein the regulating blade has a shape in which at least a part of a facing surface facing the magnet body is cut out in a thickness direction at a portion where the end portions of the magnets face each other. .   The developing device according to claim 6, wherein the notch-shaped portion is filled with a nonmagnetic member.   The cutout portion of the restriction blade is cut out with an inclined surface in the thickness direction of the restriction blade in a side view from the width direction of the restriction blade. Development device. An image carrier on which a toner image is formed on the surface;
A charging unit for charging the surface of the image carrier;
An exposure unit that exposes the surface of the image carrier charged by the charging unit to form an electrostatic latent image;
9. An image forming apparatus comprising the developing device according to claim 1 as a developing unit that supplies toner to the electrostatic latent image formed by the exposure unit to form a toner image.