JP2009157408A - Image forming unit and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make the image quality improved. <P>SOLUTION: The image forming unit is provided with a casing, a rotating sliding body arranged and freely rotating in the casing, a belt state sealing member 39, attached to the casing along the rotating sliding body and with its tip end abutted to the rotating sliding body. The attaching surface of the casing, to which the sealing member 39 is attached, is formed so that a center section is separated more from the rotating sliding body than an end section. Since the attaching surface of the casing is formed to have the center section separated more from the rotating sliding body than the end section, the casing does will no longer not come into contact with the rotating sliding body. Since the rotating sliding body can be prevented from being damaged, when printing is carried out by the image forming apparatus, formation of white spots or the formation of white stripes occurring in an image with a periodicity of the of rotation of the rotating sliding body. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming unit and an image forming apparatus.

  Conventionally, in an image forming apparatus such as a printer, a copying machine, a facsimile machine, and a multifunction machine, for example, a printer, the surface of a photosensitive drum is charged by a charging roller and exposed by an LED head to form an electrostatic latent image. Then, a toner image is formed by electrostatically attaching the toner thinned on the developing roller to the electrostatic latent image, and the toner image is transferred onto a sheet by a transfer roller to form an image. In the printer, the toner remaining on the photosensitive drum after the transfer can be removed by a cleaning device.

  By the way, the charging roller, the photosensitive drum, the developing roller, the cleaning device, and the like are supported by the casing of the image forming unit (for example, see Patent Document 1).

  A seal member is attached to the base frame constituting the casing, and the seal member closes the gap between the photosensitive drum and the base frame.

JP-A-5-224575

  However, in the conventional printer, when the image forming unit is assembled or mounted on the printer, the base frame may be pushed from the side opposite to the mounting surface for mounting the seal member. In this case, if the base frame bends in a direction approaching the photosensitive drum and comes into contact with the photosensitive drum, the photosensitive drum is damaged.

  As a result, when printing is performed with a printer, white spots are formed in the rotation cycle of the photosensitive drum or streak-like marks that are white are formed, resulting in a reduction in image quality.

  An object of the present invention is to provide an image forming unit and an image forming apparatus capable of solving the problems of the conventional printer and improving the image quality.

  Therefore, in the image forming unit of the present invention, the housing, the rotating sliding body rotatably disposed in the casing, the leading end of the rotating sliding body abutting the rotating sliding body. And a belt-like seal member attached to the housing.

  And the attachment surface of the housing | casing to which this seal member is attached is formed so that a center part may leave | separate from a rotation sliding body rather than an edge part.

  According to the present invention, in the image forming unit, the casing, the rotary sliding body rotatably disposed in the casing, the tip is brought into contact with the rotary sliding body along the rotary sliding body. And a belt-like seal member attached to the housing.

  And the attachment surface of the housing | casing to which this seal member is attached is formed so that a center part may leave | separate from a rotation sliding body rather than an edge part.

  In this case, the mounting surface of the housing is formed such that the center portion is separated from the rotating sliding body from the end portion, so that the housing does not contact the rotating sliding body. Accordingly, since the rotating sliding body can be prevented from being damaged, when printing is performed with the image forming apparatus, white spots are formed in the rotation cycle of the rotating sliding body, or white streaks are formed on the image. It will not be done. As a result, the image quality can be improved.

FIG. 3 is a perspective view illustrating a main part of the image forming unit according to the first embodiment of the present invention. 1 is a schematic diagram of a printer according to a first embodiment of the present invention. 1 is a schematic diagram of an image forming unit according to a first embodiment of the present invention. It is a front view of the seal member and sticking part in a 1st embodiment of the present invention. It is sectional drawing of the sealing member and sticking part in the 1st Embodiment of this invention. It is a figure which shows the reference example of the sealing member and sticking part in the 1st Embodiment of this invention. It is a front view of the sealing member and sticking part in the 2nd Embodiment of this invention. It is a perspective view which shows the principal part of the base frame in the 2nd Embodiment of this invention. It is a top view which shows the principal part of the base frame in the 2nd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this case, a printer as an image forming apparatus will be described.

  FIG. 2 is a schematic view of the printer according to the first embodiment of the present invention.

  As shown in the figure, a paper feed cassette 51 as a medium accommodating portion for accommodating paper (not shown) as a medium is disposed at the lower part of the apparatus main body, and a paper is placed adjacent to the front end of the paper feed cassette 51. A sheet feeding mechanism is provided as a medium supply unit that separates and feeds sheets one by one. The paper feed mechanism includes a separation roller 52 and paper feed rollers 53a and 53b, and the paper fed by the paper feed mechanism is sent to the transport roller sections 54 and 55 disposed at the upper portion, and then the transport member. The image forming units 10Bk, 10Y as a plurality of image forming units that are conveyed by the conveying belt 57 and form images of black, yellow, magenta, and cyan as the conveying belt 57 is driven. 10M and 10C, and photosensitive drums 12Bk, 12Y, 12M, and 12C as image carriers that are rotatably disposed in the image forming units 10Bk, 10Y, 10M, and 10C, and transfer rollers as transfer members Passes between 24Bk, 24Y, 24M, and 24C. The transfer rollers 24Bk, 24Y, 24M, and 24C sequentially transfer the toner images as the developer images of the respective colors formed on the respective photosensitive drums 12Bk, 12Y, 12M, and 12C onto the paper, and color toners. Form an image.

  Subsequently, the paper is sent to a fixing device 25 as a fixing device, and the color toner image is fixed on the paper in the fixing device 25 to form a color image. The paper discharged from the fixing device 25 is transported by the transport roller 59, and then discharged from the apparatus main body by the discharge transport roller 60, and stacked on the upper cover 63 as a medium stacking unit.

  In order to form the electrostatic latent image as a latent image by exposing the surface of each of the photoconductive drums 12Bk, 12Y, 12M, and 12C, the LED heads 27Bk, 27Y, 27M, and 27C as the exposure device form each image. The units 10Bk, 10Y, 10M, and 10C are arranged to face each other.

  Each of the image forming units 10Bk, 10Y, 10M, and 10C is detachably disposed with respect to the apparatus main body. For this purpose, the upper cover 63 is disposed to be openable and closable at the upper part of the apparatus main body. The LED heads 27Bk, 27Y, 27M, and 27C are held by the upper cover 63.

  The image forming units 10Bk, 10Y, 10M, and 10C, the LED heads 27Bk, 27Y, 27M, and 27C, the transfer rollers 24Bk, 24Y, 24M, and 24C, the fixing device 25, and the like constitute a printer.

  Next, the image forming units 10Bk, 10Y, 10M, and 10C will be described. In this case, since the image forming units 10Bk, 10Y, 10M, and 10C have the same structure, only the image forming unit 10Bk will be described.

  FIG. 3 is a schematic view of the image forming unit according to the first embodiment of the present invention.

  The image forming unit 10Bk includes a main body of the image forming unit 10Bk, that is, an image forming unit main body 20, and a toner cartridge 21 as a developer cartridge that is detachably attached to the image forming unit main body 20. The toner cartridge 21 contains toner as a developer.

  In addition, the image forming unit 10Bk includes a conductive base layer made of aluminum or the like, and a photosensitive drum 12Bk constituted by a surface layer made of an organic photosensitive member, a conductive metal shaft, and a semiconductive material such as epichlorohydrin rubber. A charging roller 13 as a charging member formed by coating a conductive rubber in a roll shape, and a developer carrier formed by coating a conductive metal shaft with a semiconductive rubber such as silicone. The developing roller 16 and a conductive metal shaft are coated with a foamed rubber material (formed by adding a foaming agent during rubber kneading) in order to improve toner conveyance. The developer supply member 18 is a toner supply roller 18, and the developer roller 16 is disposed with its tip in contact with the development roller 1. A developing blade 17 as a developer regulating member for uniformly thinning the toner supplied to the toner, and a cleaning as a cleaning member for removing the toner remaining on the photosensitive drum 12Bk after the toner image is transferred to the paper P. The blade 19 includes a stirrer 26 formed above the toner supply roller 18 and disposed in a storage chamber 30 for storing toner. The toner in the toner cartridge 21 is supplied to the image forming unit main body 20 through the discharge port 22 and stirred by the stirrer 26.

  The housing of the image forming unit main body 20 includes a base frame 14 mainly constituting a lower portion and a cover frame 15 covering the base frame 14.

  The developing blade 17 is sandwiched between support members 17a and 17b and fixed to the cover frame 15 by screws (not shown). The cleaning blade 19 is strongly bonded to a bracket 33 having rubber such as urethane rubber by an adhesive member such as hot melt, and is attached to the base frame 14 in this state. In the gap below the cleaning blade 19, there is disposed a waste toner conveying member 40 that is made of a spiral or a coil spring and conveys the toner removed by the cleaning blade 19 as waste toner.

  A charging roller 13, a developing roller 16, and a cleaning blade 19 are disposed in contact with the photosensitive drum 12Bk, and a developing blade 17 and a toner supply roller 18 are disposed in contact with the developing roller 16. . The photosensitive drum 12Bk, the charging roller 13, the developing roller 16, and the toner supply roller 18 are rotationally driven in the direction of the arrow by a rotation driving system (not shown), and a power source for the developing roller 16 (not shown) and a toner supply roller 18 are used. A power source and a power source for the developing blade 17 are connected to the developing roller 16, the toner supply roller 18, and the developing blade 17, respectively.

  Further, the photosensitive drum 12Bk and the charging roller 13 are rotatably supported by side frames (not shown) as side casings disposed at both left and right ends in the axial direction of the photosensitive drum 12Bk. Note that the base frame 14 and the cover frame 15 are made of a resin having high hardness and high heat resistance, in this embodiment, modified PPE.

  A seal member 39 as a first sealing portion is disposed on the base frame 14 on the downstream side of the transfer roller 24Bk in the rotation direction of the photosensitive drum 12Bk and on the upstream side of the cleaning blade 19, The seal member 39 is affixed to the end surface of the opening of the base frame 14, that is, the mounting surface s1, with the tip abutting against the photoconductive drum 12Bk so as to close the gap between the photoconductive drum 12Bk and the base frame 14. It is attached. The photosensitive drum 12Bk constitutes a first rotating sliding body that rotates while sliding with the seal member 39.

  Further, a seal member 23 as a second sealing portion is disposed downstream of the toner supply roller 18 in the rotation direction of the developing roller 16 and upstream of the photosensitive drum 12Bk. Is attached to the base frame 14 with its tip abutting against the developing roller 16 so as to close the gap between the developing roller 16 and the base frame 14. The developing roller 16 constitutes a second rotating sliding body that rotates while sliding with the seal member 23.

  Next, the operation of the image forming unit 10Bk will be described.

  In the printer having the above-described configuration, when a drive motor (not shown) is driven and the power supply circuit is operated, both the developing roller 16 and the toner supply roller 18 rotate clockwise, and toner is supplied from the toner supply roller 18 to the developing roller 16. Supplied. The toner supplied to the developing roller 16 is sent to the pressure contact portion between the developing roller 16 and the developing blade 17 by the rotation of the developing roller 16, and after passing through the developing blade 17, the thickness of the toner layer on the developing roller 16 is increased. To be uniform. The toner is conveyed to the photosensitive drum 12Bk as the developing roller 16 rotates. The surface of the photosensitive drum 12Bk is uniformly charged by the charging roller 13, an electrostatic latent image is formed by the LED head 27Bk, and the toner attached on the developing roller 16 is attached to the electrostatic latent image. A toner image is formed.

  Then, the toner remaining on the photosensitive drum 12Bk after the toner image is transferred to the paper P is removed by the cleaning blade 19, and the removed toner is a waste formed adjacent to the cleaning blade 19. The toner is collected in a toner collecting unit 91 as a developer collecting unit, conveyed by a waste toner conveying member 40, and sent to a waste toner collecting chamber 21a as a waste developer collecting chamber formed in the toner cartridge 21 and collected. The In the meantime, the seal member 39 seals the toner collecting portion 91 while the tip is brought into contact with the photosensitive drum 12Bk and is slid.

  Next, the arrangement state of the seal member 39 will be described.

  FIG. 1 is a perspective view showing a main part of an image forming unit according to the first embodiment of the present invention, FIG. 4 is a front view of a seal member and a sticking portion according to the first embodiment of the present invention, and FIG. It is sectional drawing of the sealing member and sticking part in the 1st Embodiment of this invention.

  As shown in FIG. 1, the seal member 39 is affixed to a mounting surface s1 (FIG. 3) formed at the end of the opening of the base frame 14, and when the photosensitive drum 12Bk is rotated, a rotation load is applied. Can be used even if the usage environment of the printer is changed, without causing a damage to the surface of the photoconductive drum 12Bk, or damaging the surface of the photoconductive drum 12Bk. In order to be able to do, it is formed with a film-like insulator, in the present embodiment, a thermoplastic urethane film.

  Further, as shown in FIG. 4, the seal member 39 is formed in a strip shape so as to extend along the axial direction of the photosensitive drum 12Bk, and the vicinity of one edge portion eg1 of the seal member 39 is the mounting surface. The other edge part eg2 that is affixed to s1 and forms the tip of the seal member 39 is brought into contact with the photosensitive drum 12Bk. And along the said edge part eg1, the very thin strip | belt-shaped sticking part 28 for attaching to the base frame 14 is formed in the sealing member 39, and the center part of the said edge part eg2 becomes higher than an edge part ( It is curved so as to protrude toward the photosensitive drum 12Bk) and is formed in an arc shape.

  As shown in FIG. 5, the sticking portion 28 includes two double-sided tapes 28a as double-sided sticking elements having both surfaces formed of an adhesive, a thin plate 28b sandwiched between the double-sided tapes 28a, and a peeling member. The double-sided tape 28a, the thin plate 28b, the double-sided tape 28a and the release paper 28c are laminated in this order from the seal member 39 side, and can be attached by peeling the release paper 28c. The release paper 28c is attached to the double-sided tape 28a in advance.

  Further, since the thin plate 28b is formed of a material having higher bending rigidity than the seal member 39 (for example, stainless steel (SUS), polyethylene resin, etc.), when the seal member 39 is attached to the base frame 14, the seal member It is possible to prevent wrinkles from being formed on the surface 39 and improve the pasting property.

  In the sealing member 39 of the present embodiment, the length La is 325 [mm], the height Ba of the end is 6.5 [mm], and the height difference ΔBa between the end and the center is 0. The height (width) Bt of the double-sided tape 28a and the thin plate 28b is 3 [mm], and the thickness of the seal member 39 is 0.2 [mm]. The curvature radius R of the edge eg2 is set so that the height difference ΔBa between the end and the center is 0.5 [mm].

  FIG. 6 is a diagram showing a reference example of the sealing member and the sticking portion in the first embodiment of the present invention.

  Incidentally, the seal member 39 is attached to the attachment surface s1 in advance by the double-sided tape 28a (FIG. 5) before assembling the image forming unit 10Bk (FIG. 3). At that time, the seal member 39 presses the photosensitive drum 12Bk. At this time, the edge portion eg2 of the seal member 39 is elastically deformed, and the photosensitive drum 12Bk is pressed by the urging force generated by the elastic deformation. Along with this, the reaction force acts on the mounting surface s1, so that the flat mounting surface s1 formed on a straight line is bent in an arc shape in a direction away from the photosensitive drum 12Bk. Therefore, the interval between the mounting surface s1 and the photosensitive drum 12Bk is not uniform in the longitudinal direction.

  In this case, if the seal member 39 is formed so that one edge part eg11 and the other edge part eg12 extend in a straight line and parallel to each other, as shown in the drawing, the mounting surface s1 Is bent in an arc shape, a variation occurs in the force with which the seal member 39 presses the photosensitive drum 12Bk, that is, the pressing force. That is, the pressing force in the vicinity of the central portion in the axial direction of the photosensitive drum 12Bk is smaller than the pressing force at both ends, or between the edge eg12 and the photosensitive drum 12Bk in the central portion in the axial direction of the photosensitive drum 12Bk. A gap is formed on the surface.

  Therefore, in the present embodiment, as described above, the edge part eg2 is formed in an arc shape. Therefore, the pressing force in the vicinity of the central portion in the axial direction of the photoconductive drum 12Bk is not smaller than the pressing force at both ends, and can be made substantially uniform in the axial direction. In addition, no gap is formed in the central portion of the photosensitive drum 12Bk in the axial direction.

  Therefore, since the toner in the toner collecting unit 91 is not scattered, the image quality can be improved, and the paper P and the inside of the apparatus main body can be prevented from being stained.

  In the present embodiment, since the edge portion eg2 has a curved shape, the cost of the mold for molding the seal member 39 is increased, and as a result, the cost of the seal member 39 is increased. Therefore, a second embodiment of the present invention that can reduce the cost of the seal member 39 will be described. In addition, about the thing which has the same structure as 1st Embodiment, the same code | symbol is provided and the effect of the same embodiment is used about the effect of the invention by having the same structure.

  FIG. 7 is a front view of a sealing member and a sticking portion in the second embodiment of the present invention.

  In this case, the sealing member 39 as the first sealing portion includes one edge portion eg21 and the other edge portion eg22, and the edge portion eg22 has a central portion higher than the end portion (on the photosensitive drum 12Bk side). It is formed in a trapezoidal shape so as to protrude. That is, the edge eg22 extends in parallel with the edge eg21 over a predetermined distance, and is formed in a straight line from the end of the center m1 to the end of the seal member 39. It is provided with an inclined portion m2 formed to be inclined.

  In the sealing member 39 of the present embodiment, the length Lb is 325 [mm], the end height Bb is 6.5 [mm], and the height difference ΔBb between the end and the center is 0. The height (width) Bt of the double-sided tape 28a and the thin plate 28b is 3 [mm], and the thickness of the seal member 39 is 0.2 [mm].

  Also in this case, the pressing force in the vicinity of the central portion in the axial direction of the photosensitive drum 12Bk (FIG. 3) as the image carrier is not smaller than the pressing force at both ends, and can be made substantially uniform in the axial direction. . In addition, no gap is formed in the central portion of the photosensitive drum 12Bk in the axial direction.

  And since the center part m1 and the inclination part m2 can be formed in linear form, a big thing can be used as a metal mold | die for shape | molding the sealing member 39. FIG. Therefore, the cost of the mold can be reduced, and as a result, the cost of the seal member 39 can be reduced.

  FIG. 8 is a perspective view showing the main part of the base frame in the second embodiment of the present invention, and FIG. 9 is a plan view showing the main part of the base frame in the second embodiment of the present invention.

  In this case, the attachment surface s2 for attaching the seal member 39 (FIG. 7) on the base frame 14 is formed in an arc shape by curving so that the center part is away from the photosensitive drum 12Bk (FIG. 3) side from the end part. Is done.

  Therefore, by changing the molding conditions such as temperature and time when the base frame 14 is molded by injection molding to a predetermined value, the mounting surface s2 is formed in an arc shape by using the warp when the molding is completed. can do. In addition, a portion corresponding to the mounting surface s2 in the mold for forming the base frame 14 can be curved.

  In the mounting surface s2 of the present embodiment, the length L is 325 [mm], and the radial distance (depth) ΔEa between the end and the center is 0.5 [mm].

  The shape of the seal member 39 is the same as that in the first embodiment.

  By the way, when the image forming unit 10Bk as an image forming unit is assembled or mounted on a printer, the base frame 14 may be pushed from the side opposite to the mounting surface s2, and in this case, the photosensitive drum 12Bk is pressed against the photosensitive drum 12Bk. It bends in the approaching direction and comes into contact with the photosensitive drum 12Bk. In this case, if the photosensitive drum 10Bk is damaged, when printing is performed with a printer, white spots are formed in the color image at the rotation cycle of the photosensitive drum 10Bk, or streaky traces that are white are formed. As a result, the image quality is degraded.

  Therefore, in the present embodiment, as described above, the center portion of the mounting surface s2 is curved away from the end portion from the photosensitive drum 12Bk side and is formed in an arc shape. There is no contact. Therefore, it is possible to prevent the photosensitive drum 10Bk from being damaged. Therefore, when printing is performed by a printer, white spots are formed in the color image at the rotation cycle of the photosensitive drum 10Bk, or white traces are formed. Will not be formed. As a result, the image quality can be improved.

  In each of the above embodiments, the seal member 39 has been described, but the present invention can be applied to the seal member 23.

  In each of the above embodiments, a printer has been described. However, the present invention can be applied to a copying machine, a facsimile machine, a multifunction machine, and the like.

  The present invention is not limited to the above embodiments, and various modifications can be made based on the gist of the present invention, and they are not excluded from the scope of the present invention.

10Bk, 10Y, 10M, 10C Image forming units 12Bk, 12Y, 12M, 12C Photosensitive drum 14 Base frame 15 Cover frame 16 Developing rollers 23, 39 Seal members s1, s2 Mounting surface

Claims (5)

(A) a housing;
(B) a rotating sliding body disposed rotatably in the housing;
(C) having a belt-like seal member attached to the casing along the rotary sliding body and having the tip abutting on the rotary sliding body;
(D) The image forming unit characterized in that the mounting surface of the casing to which the seal member is mounted is formed such that the central portion is separated from the rotary sliding body from the end portion.   The image forming unit according to claim 1, wherein the attachment surface is curved and formed in an arc shape.   The image forming unit according to claim 1, wherein the rotary sliding body is a photosensitive drum.   The image forming unit according to claim 1, wherein the rotary sliding body is a developing roller.   An image forming apparatus on which the image forming unit according to claim 1 is mounted.

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