JP2007316456A - Developing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device which can prevent a variation of a polar angle by firmly fixing a magnet roller in the rotational direction and in the thrust direction with a pole fixing member, and can be assembled easily, and of which pole fixing member can be reused after the device is disassembled. <P>SOLUTION: The pole fixing member 18 for controlling the rotation of the magnet roller 14 is a plate member formed by bending a metal piece to a predetermined shape, and a press-fitting part 22 is press-fitted and fixed to a fixing groove 23 provided on the edge surface of a spindle 14a of the magnet roller 14. The pole fixing member 18 is fixed to a housing 5 with a screw 20 through an elongate hole 18b of circular arc. The polar angle of the magnet roller 14 can be adjusted by rotating the pole fixing member 18 in both ways within the limits of the elongate hole 18b. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a copying machine, a facsimile machine, and a printer, and a developing device used therefor, and more particularly to a mechanism for fixing a magnetic field generating member disposed inside a developer carrier.

  In an image forming apparatus using an electrophotographic system such as a copying machine, a printer, or a FAX, a powder developer is mainly used, and an electrostatic latent image formed on an image carrier such as a photosensitive drum is used as a developing device. In general, a process is performed in which the visible image is visualized and the visible image is transferred onto a recording medium, and then a fixing process is performed.

  12A and 12B are a plan view and a front view of a conventional developing device. As illustrated in FIG. 12, the developing device 21 includes a housing (housing) 5, a cover (housing) 6, a first agitating screw (rotary conveying unit) 7, a second agitating screw (rotating and conveying unit) 8, a developing roller. (Developer carrier) 11 and a regulation blade (regulation member) 12 are included. In FIG. 12A, for the sake of convenience, the inside of the cover 6 is excluded so that the inside can be seen.

  The housing 5 stores developer (hereinafter referred to as toner), and a first storage chamber 15 and a second storage chamber 16 are formed by a partition plate 9 formed integrally with the housing 5. The first storage chamber 15 is provided with a first stirring screw 7, and the second storage chamber 16 is provided with a second stirring screw 8. The upper portion of the housing 5 is sealed with a cover 6 so that the stored toner or the like does not leak outside.

  As shown in FIG. 12A, the partition plate 9 does not exist at both ends of the housing 5 in the longitudinal direction, and toner can be transferred between the first stirring screw 7 and the second stirring screw 8. The first stirring screw 7 conveys the toner stored in the first storage chamber 15 in the direction of the arrow P while stirring the toner, and guides it to the second storage chamber 16. The second stirring screw 8 receives the second storage screw 8. The toner conveyed to the chamber 16 is conveyed in the direction of the arrow Q while being agitated and supplied to the developing roller 11. The first agitation screw 7 and the second agitation screw 8 have a configuration in which the spiral wings 7b and 8b are provided around the support shafts 7a and 8a, respectively, and in the housing 5 in a state parallel to each other. It is pivotally supported by the shaft.

  The developing roller 11 supplies toner to the photosensitive layer of the photosensitive drum by rotating in accordance with the rotation of the photosensitive drum (not shown). Inside the developing roller 11, a magnet roller (magnetic field generating member) 14 made of a permanent magnet having a plurality of magnetic poles is fixed. The magnetic force of the magnet roller 14 causes toner to adhere (carry) on the surface of the developing roller 11 to form a toner thin layer. The developing roller 11 is rotatably supported in the housing 5 in a state parallel to the first stirring screw 7 and the second stirring screw 8. The first stirring screw 7, the second stirring screw 8, and the developing roller 11 are rotationally driven by driving means (not shown).

  The regulating blade 12 is disposed at a predetermined interval from the developing roller 11 and regulates the amount of toner supplied to the photosensitive drum. As the material of the regulating blade 12, SUS (stainless steel) or the like that is magnetic or non-magnetic is used. Note that magnetism may be imparted by attaching a permanent magnet to the non-magnetic regulating blade 12. A toner sensor (not shown) for detecting the amount of toner (or toner concentration) stored in the housing 5 is provided on the bottom surface of the second storage chamber 16 facing the second stirring screw 8. .

  DS rollers 17 a and 17 b are rotatably inserted into the flange portion of the developing roller 11. The DS rollers 17a and 17b are in contact with both ends of the photosensitive drum, so that the distance between the developing roller 11 and the photosensitive drum is strictly regulated. The DS rollers 17a and 17b have built-in bearings, and can be prevented from being worn on the surface of the photosensitive drum by rotating following the photosensitive drum.

  Reference numeral 18 denotes a pole fixing member that regulates the rotation of the magnet roller 14 and performs positioning in the thrust direction (axial direction; left-right direction in FIG. 12), and is fixed to the housing 5 by screws 20. As shown in FIG. 13, the pole fixing member 18 is formed with a D-cut hole 18 a through which the tip of the support shaft 14 a of the magnet roller 14 passes.

  In the developing device as described above, since the D cut hole 18a of the pole fixing member 18 needs to be managed in the linear portion and the arc portion, it is difficult to obtain the component accuracy of the magnet roller 14 and the pole fixing member 18. Therefore, considering assembly workability, as shown in FIG. 13, the outer diameter a of the arc portion of the support shaft 14a, the inner diameter a 'of the arc portion of the D-cut hole 18a, and the outer diameter b of the support shaft 14a in the vertical direction It is necessary to provide a predetermined clearance or more between the support shaft 14a and the D-cut hole 18a by setting the relationship of the inner diameter b 'in the vertical direction of the D-cut hole 18a as a <a' and b <b '. There is.

  However, since the arrangement angle of each pole of the magnet roller 14 (hereinafter referred to as the pole angle) varies by the clearance, there is a possibility of causing an abnormal image such as generation of aggregated toner and defective density. Further, if the magnet roller 14 is displaced in the thrust direction, it is possible that the DS rollers 17a and 17b may be poorly rotated due to being pressed by the gear or the housing, or the bearing member may be damaged.

  Further, for example, in Patent Document 1, the electrode fixing member 18 is also used as an electrode plate for applying a developing bias to the developing roller 11, so that the number of parts can be reduced and the configuration can be simplified without separately providing an electrode. Although the apparatus is disclosed, in the configuration as shown in FIG. 13, the contact (conduction) between the support shaft 14a and the D-cut hole 18a becomes unstable due to the clearance, so that no bias is applied to the developing roller 11 and the image is missing. Or cause electrical noise.

  Then, the method of preventing the fluctuation | variation of the pole angle and contact failure of a magnet roller by fixing a magnet roller and a pole fixing member firmly is proposed, and as shown in FIG. A developing device is disclosed that fixes and axially positions the magnet roller 14 by providing a claw portion 19 that presses the support shaft 14a of the magnet roller 14 against the edge of the D-cut hole 18a.

  However, in the method of Patent Document 2, in consideration of the mass productivity of the pole fixing member 18, as shown in FIG. Therefore, the width c of the claw portion 19 that presses the support shaft 14a becomes narrow, and the fixing force in the rotation direction (arrow AA ′ direction) becomes weak as shown in the right diagram of FIG. In particular, in the case of a developing device using a two-component developer, a large load is applied to the shaft portion of the developing roller, so that the claw portion 19 may be deformed with time and the polar angle may vary.

  A method of increasing the pressing force by the claw portion 19 by increasing the dimensional accuracy of the pole fixing member 18 or using a thick metal plate is also conceivable. However, the support shaft 14a is connected to the D-cut hole 18a. Since the bending resistance of the claw portion 19 is increased during insertion, the assembling workability is reduced, and if it is forcibly inserted, the thrust direction (arrow BB 'direction) falls as shown in the left figure of FIG. 14 (b). Or the pole fixing member 18 may be deformed.

Furthermore, in recent image forming apparatuses, recyclability of each process unit is regarded as important in order to reduce the environmental load. However, in the method of Patent Document 2, the claw portion 19 is deformed when the unit is disassembled. There is also a problem that the pole fixing member 18 cannot be reused.
Japanese Patent Laid-Open No. 9-22189 Japanese Patent Application Laid-Open No. 9-90762

  In view of the above problems, the present invention prevents the fluctuation of the polar angle by firmly fixing the magnet roller in the rotation direction and the thrust direction by the pole fixing member, and also facilitates the assembly work and allows the pole fixing member to be reassembled at the time of disassembly. An object of the present invention is to provide a developing device that can be used.

  To achieve the above object, the present invention provides a housing for storing a magnetic developer, and a developer supplied from the housing in which a magnetic field generating member having a plurality of magnetic poles is rotatably arranged. A developer carrying member to be carried, a pole fixing member that is fixed to one end of a support shaft of the magnetic field generating member and restricts the rotation of the magnetic field generating member, and is arranged to face the developer carrying member and is supplied onto the photosensitive drum. In a developing device including a magnetic or non-magnetic regulating member that regulates the amount of developer to be formed, a fixing groove is formed on an end surface of the support shaft, and at least a part of the pole fixing member is formed. A press-fitting portion that is press-fitted into the fixing groove is projected.

  According to the present invention, in the developing device configured as described above, the pole fixing member presses the magnetic field generating member in the axial direction by an elastic force.

  According to the present invention, in the developing device configured as described above, the pole fixing member has an arc-shaped elongated hole that is a part of a circumference centered on the support shaft when the press-fitting portion is press-fitted into the fixing groove. And is fixed to the housing through the elongated hole.

  According to the present invention, in the developing device configured as described above, the fixing groove is provided so as to divide the end surface of the support shaft into two parts, and the press-fitting portion is press-fitted in the entire fixing groove.

  According to the present invention, in the developing device configured as described above, the pole fixing member is a sheet metal member, and the press-fitting portion is formed by bending a part of the pole fixing member into a V-shaped cross section.

  According to the present invention, in the developing device configured as described above, the pole fixing member is a sheet metal member having a predetermined thickness or more, and the press-fitting portion is formed by bending an end portion of the pole fixing member substantially vertically. It is a feature.

  According to the present invention, in the developing device configured as described above, the cross-sectional shape of the press-fitting portion is tapered.

  According to the present invention, in the developing device configured as described above, the cross-sectional shape of the fixed groove is tapered.

  According to the present invention, in the developing device configured as described above, a press-fitting position is marked on the press-fitting portion.

  According to the present invention, in the developing device configured as described above, the fixing groove is formed so as to be shifted from an axis of the support shaft.

  According to the present invention, in the developing device configured as described above, the protruding amount of the press-fitting portion is equal to or less than the depth of the fixing groove, and the press-fitting portion is press-fitted into the fixing groove until the pole fixing member contacts the end surface of the support shaft. It is characterized by that.

  According to the present invention, in the developing device configured as described above, the amount of protrusion of the press-fit portion is larger than the depth of the fixed groove, and the press-fit portion is press-fitted into the fixed groove until the tip of the press-fit portion reaches the bottom surface of the fixed groove. It is characterized by that.

  According to the present invention, in the developing device configured as described above, screw holes are provided in side surfaces of the fixing groove and the press-fitting portion, and the press-fitting portion is press-fitted into the fixing groove until each screw hole overlaps. It is characterized by being screw-fixed.

  According to the present invention, in the developing device configured as described above, a developing bias is applied via the pole fixing member.

  According to the first configuration of the present invention, since the support shaft of the magnetic field generating member and the pole fixing member can be firmly fixed with a simple configuration, the positioning of the magnetic field generating member in the rotational direction can be strictly performed, and Variation in polar angle after positioning can be suppressed. In addition, since the component accuracy is not required as compared with the conventional configuration, the manufacturing cost of the component can be reduced.

  According to the second configuration of the present invention, in the developing device having the first configuration, the thrust of the magnetic field generating member is pressed by pressing the magnetic field generating member in the thrust direction using the elastic force of the pole fixing member. Directional movement can be effectively prevented.

  According to the third configuration of the present invention, in the developing device having the first or second configuration, the pole fixing member is screw-fixed to the casing through the arc-shaped long hole provided in the pole fixing member. By doing so, it becomes possible to adjust the pole angle of the magnetic field generating member by changing the screw fixing position within the range of the elongated hole. Further, since the distance between the screw fixing position and the support shaft does not change, the positional relationship between the magnetic field generating member and the regulating member is kept constant regardless of the polar angle.

  According to the fourth configuration of the present invention, in the developing device having any one of the first to third configurations, the fixing groove is provided so as to divide the end surface of the support shaft into two parts, and the press-fitting portion is arranged over the entire fixing groove. Since the entire ridge line of the fixing groove and the press-fitting portion are in line contact with each other, the rattling between the pole fixing member and the support shaft is eliminated, and the magnetic field generating member can be positioned more precisely in the rotational direction. it can.

  Further, according to the fifth configuration of the present invention, in the developing device of the fourth configuration, the pole fixing member is a sheet metal member, and a part thereof is bent into a V-shaped cross section to form a press-fit portion. Since the press-fitting part can be easily formed and the V-shaped press-fitting part is bent by a predetermined amount and is press-fitted into the fixing groove, the pole fixing member and the support shaft can be firmly fixed using the elastic force of the sheet metal member. Further, since the press-fitting portion can be easily pulled out, the pole fixing member can be reused.

  According to the sixth configuration of the present invention, in the developing device according to the fourth configuration, the pole fixing member is a sheet metal member having a predetermined thickness or more, and the end portion thereof is bent substantially vertically to form the press-fit portion. By doing so, the press-fitting portion can be formed easily, and the entire pole fixing member including the press-fitting portion is formed of a thick sheet metal, so that the pole fixing member and the support shaft can be more firmly fixed.

  According to the seventh configuration of the present invention, in the developing device of the sixth configuration, the press-fitting operation of the press-fitting portion of the pole fixing member is facilitated by making the cross-sectional shape of the press-fitting portion tapered.

  Further, according to the eighth configuration of the present invention, in the developing device of the sixth configuration, the press-fitting operation of the press-fitting portion of the pole fixing member is facilitated by making the cross-sectional shape of the fixing groove tapered. Further, taper processing can be easily performed as compared with processing of the press-fitting portion.

  Further, according to the ninth configuration of the present invention, in the developing device having any one of the fifth to eighth configurations, the press-fitting position is marked on the press-fitting portion, so that the press-fitting position into the fixing groove at the time of assembling work. Can be seen at a glance, improving work efficiency and reducing the occurrence of press-fitting mistakes.

  According to the tenth configuration of the present invention, in the developing device having any one of the fourth to ninth configurations, the fixing groove is formed so as to be shifted from the axis of the support shaft. Since the direction can be easily confirmed, there is no possibility that the mounting direction of the magnetic field generating member is wrong during assembly.

  According to the eleventh configuration of the present invention, in the developing device having any one of the first to tenth configurations, the amount of protrusion of the press-fitting portion is set to be equal to or less than the depth of the fixing groove, and the pole fixing member is the supporting shaft. By press-fitting until it comes into contact with the end face, positioning work in the thrust direction of the magnetic field generating member is facilitated.

  According to the twelfth configuration of the present invention, in the developing device having any one of the first to tenth configurations, the protruding amount of the press-fit portion is made larger than the depth of the fixing groove, and the tip of the press-fit portion is fixed. By press-fitting until reaching the bottom surface of the groove, the magnetic field generating member can be easily positioned in the thrust direction.

  According to the thirteenth configuration of the present invention, in the developing device having any one of the first to tenth configurations, the screw holes are provided on the side surfaces of the fixing groove and the press-fitting portion, and the screw holes are overlapped with each other. Positioning the magnetic field generating member in the thrust direction is facilitated by press-fitting the press-fitting portion into the fixing groove and fixing with screws. Further, the fixing strength of the magnetic field generating member in the rotating direction is also increased by the screw fixing.

  According to the fourteenth configuration of the present invention, in the developing device having any one of the first to thirteenth configurations, the developing bias is applied via the pole fixing member, so that the gap between the pole fixing member and the support shaft is increased. Therefore, it is possible to stably apply a bias.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic sectional view of an image forming apparatus (for example, a printer) provided with the developing device of the present invention. The printer 100 includes a photosensitive drum 41, a charging unit 42, an image writing unit (laser scan unit) 43, a developing device 21, a toner storage unit 44, a transfer unit 45, a cleaning unit 46, a sheet storage unit 51, and a conveyance unit 52. , A fixing unit 53, and a paper discharge unit 54.

  The photosensitive drum 41 is formed, for example, by laminating a photosensitive layer on an aluminum drum, and the surface is uniformly charged by the charging unit 42. Then, an electrostatic latent image in which charging is attenuated is formed on the surface that has received a laser beam from an image writing unit 43 described later. The photosensitive layer is not particularly limited, but for example, amorphous silicon (a-Si) having excellent durability is preferable.

  The charging unit (charging charger) 42 charges the surface of the photosensitive drum 41 by discharging (for example, corona discharge). For example, the charging unit 42 has a thin wire or the like, and uses this as an electrode to discharge when a high voltage is applied. The image writing unit (LSU) 43 irradiates the photosensitive drum 41 with a light beam (for example, a laser beam) based on the image data, and forms an electrostatic latent image on the photosensitive drum 41. The image data is transmitted from a personal computer (PC) (not shown).

  The developing device 21 attaches toner to the electrostatic latent image on the photosensitive drum 41 to form a toner image. Examples of the toner stored in the developing device 21 include a two-component developer composed of a toner component and a carrier, and a one-component developer composed only of a toner component. The internal configuration of the developing device 21 will be described later.

  The toner storage unit (hopper) 44 supplies the toner to the developing device 21 and stores the toner when the toner in the developing device 21 becomes insufficient. The transfer unit 45 transfers the toner image formed on the surface of the photoconductive drum 41 to the conveyed sheet without disturbing the toner image.

  The cleaning unit 46 removes the toner (residual toner) remaining on the surface of the photosensitive drum 41 after the toner image is transferred (transferred) to the sheet. For example, it is composed of a blade material that makes line contact with the longitudinal direction of the photosensitive drum 41, a spiral that conveys residual toner scraped off by the blade material to a collection tank (not shown), and the like. The sheet storage unit 51 stores a sheet (paper, OHP, etc.) on which an image (toner image) is finally printed, and sends the sheet to the transport unit 52.

  The conveyance unit 52 is a sheet path from the sheet storage unit 51 to the paper discharge unit 54. The fixing unit 53 converts the toner image transferred onto the sheet into a stable permanent image. For example, the fixing unit 53 melts the powder toner image by applying energy such as heat or pressure. The paper discharge unit 54 accommodates a sheet that has passed through the fixing unit 53, that is, a sheet on which a permanent image is printed.

  The LSU 43 emits a laser beam (light beam) onto the photosensitive drum 41 that is uniformly charged by the charging unit 42, thereby forming an electrostatic latent image on the surface of the photosensitive drum 41 based on previously input image data. Let Thereafter, the developing device 21 attaches toner to the electrostatic latent image (forms a toner image), and the transfer unit 45 transfers the toner image to the sheet. Next, the fixing unit 53 applies heat or the like to the sheet on which the toner image has been transferred to form a permanent image.

  FIG. 2 is a side cross-sectional view of the developing device according to the first embodiment of the present invention. Portions common to FIG. 12 of the conventional example are denoted by the same reference numerals and description thereof is omitted. In FIG. 2, since a predetermined pole (for example, N pole) of the magnetic field generating member 14 faces the restriction blade 12, the restriction blade 12, the developing roller 11, and the like can be obtained by using a nonmagnetic material or a magnetic material as the restriction blade 12. A magnetic field is generated in the direction attracted between the two.

  This magnetic field forms a so-called magnetic brush in which the toner stands up like a brush. When the developing roller 11 rotates and the magnetic brush moves to a position facing the photoconductive drum 41, a magnetic field having a reverse polarity is applied by the next pole (S pole) of the magnet roller 14, so that the magnetic brush is photosensitive. A toner image is formed in contact with the surface of the body drum 41.

  When the developing roller 11 further rotates, a magnetic field having a reverse polarity is applied by the next pole (N pole), and the toner that has not been used to form the toner image is collected in the developing device 21, and further the next pole (S Since the magnetic field having the opposite polarity is applied by the pole), the toner is detached from the developing roller 11 in the developing device 21. Then, after being stirred and transported by the second stirring screw 8, it adheres again to the developing roller 11 by the magnetic field of the magnet roller 14.

  That is, the toner adhesion to the developing roller 11 is strictly controlled not only by the distance between the regulating blade 12 and the developing roller 11 but also by the magnetic field generated by the magnet roller 14. Therefore, it is necessary to fix the magnet roller 14 in the rotational direction and the thrust direction so that the positional relationship with respect to the regulating blade 12 does not change.

  The pole fixing member 18 for restricting the rotation of the magnet roller 14 is a sheet metal member formed by bending a metal plate into a predetermined shape, and the press-fit portion 22 formed slightly below the center is a support shaft of the magnet roller 14. It is press-fitted and fixed in a fixing groove 23 (see FIG. 3) provided at the tip of 14a. The pole fixing member 18 is fixed to the housing 5 by a screw 20 through an arc-shaped long hole 18b. By rotating the pole fixing member 18 within the range of the long hole 18b, the pole of the magnet roller 14 is fixed. The angle can be adjusted.

  When the press-fit portion 22 is press-fitted into the fixed groove 23, the long hole 18b is formed so as to draw an arc centered on the support shaft 14a. Thereby, even if the pole angle is adjusted by changing the fixing position of the screw 20, the distance between the screw 20 and the support shaft 14a does not change, so that the positional relationship between the magnet roller 14 and the regulating blade 12 is kept constant.

  3A and 3B are a side sectional view and a plan view of the support shaft 14a and the pole fixing member 18 used in the developing device of the first embodiment. As shown in FIG. 3A, the press-fit portion 22 is formed in a V shape in a sectional view. When the maximum width of the press-fit portion 22 is t1 and the groove width of the fixed groove 23 is t2, t1> t2. By designing in this manner, the press-fitting portion 22 is bent by a predetermined amount and press-fitted into the fixing groove 23, so that the pole fixing member 18 and the support shaft 14a can be firmly fixed using the elastic force of the sheet metal member.

  The fixing groove 23 is formed so as to divide the end surface of the support shaft 14a into two parts. Thereby, since the ridge line 23a of the fixing groove 23 and the press-fit portion 22 are in line contact with each other within the range of the diameter d of the support shaft 14a, the play between the pole fixing member 18 and the support shaft 14a is eliminated. The angle can be adjusted strictly, and the positional deviation in the rotational direction after adjusting the polar angle of the magnet roller 14 can be suppressed.

  On the other hand, since the pole fixing member 18 is a sheet metal member, the support shaft 14a is pressed in the thrust direction (the left direction in FIG. 3A) by the elastic force of the pole fixing member 18. Therefore, it is possible to simultaneously suppress the displacement of the magnet roller 14 in the thrust direction.

  Further, when a bias is applied to the developing roller 11 (see FIG. 2) via the pole fixing member 18, electrical conduction between the pole fixing member 18 and the support shaft 14a is ensured, so that the bias is stably applied. can do. Further, when the developing device 21 is disassembled, the press-fit portion 22 can be bent inward and easily pulled out from the fixing groove 23, so that the pole fixing member 18 can be reused and contributes to recycling of the developing device 21.

  FIG. 4 is a side sectional view of the developing device according to the second embodiment of the present invention. In the present embodiment, the pole fixing member 18 is formed of a thick sheet metal member, and the press-fit portion 22 is formed by bending the lower end of the pole fixing member 18 at a right angle. Since the configuration of other parts is the same as that of FIG. 1 of the first embodiment, description thereof is omitted. In addition, as thickness of the sheet metal which comprises the pole fixing member 18, about 1.6-2 mm is used suitably.

  FIGS. 5A and 5B are a side sectional view and a plan view of the support shaft 14a and the pole fixing member 18 used in the present embodiment. As shown in FIG. 5A, when the thickness of the press-fit portion 22 (sheet metal member) is t1, and the groove width of the fixing groove 23 is t2, it is designed to satisfy t1> t2, for example, t1 is 2 mm. Then, t2 is set to 1.95 to 1.99 mm. As a result, when the press-fitting portion 22 is press-fitted into the fixing groove 23, the opening end of the fixing groove 23 is slightly opened, and a force for returning to the original position is further applied to the opening end. It is firmly clamped on the inner surface.

  As in the first embodiment, the fixing groove 23 is formed so that the end surface of the support shaft 14a is divided into two. As a result, the inner surface of the fixing groove 23 and the press-fit portion 22 are in surface contact with each other within the range of the diameter d of the support shaft 14a, so that the play between the pole fixing member 18 and the support shaft 14a is eliminated. Furthermore, since electrical conduction between the pole fixing member 18 and the support shaft 14a is ensured, a bias can be stably applied.

  FIGS. 6 and 7 are a side cross-sectional view and a plan view showing another configuration example of the support shaft 14a and the pole fixing member 18 used in the second embodiment. As shown in FIG. 6A, the press-fit portion 22 of the pole fixing member 18 is tapered from the tip toward the root portion, and the tip of the press-fit portion 22 is thinner than the groove width t2 of the fixing groove 23. In addition, the maximum thickness t1 of the press-fitted portion is thicker than the groove width t2.

  With this configuration, when the press-fit portion 22 is press-fitted into the fixing groove 23 as shown in FIG. 6B, the tip of the press-fit portion 22 can be easily inserted, and the assembly workability is improved. Further, since the press-fit portion 22 is press-fitted so as to expand the inner surface of the fixed groove 23, the ridge line 23a of the fixed groove 23 and the press-fit portion 22 are firmly within the range of the diameter of the support shaft 14a shown in FIG. Line contact. Therefore, the play between the pole fixing member 18 and the support shaft 14a is eliminated, and the positioning of the magnet roller 14 in the rotational direction can be strictly performed. Further, electrical conduction between the pole fixing member 18 and the support shaft 14a is ensured.

  Further, as shown in FIGS. 7A to 7C, the fixing groove 23 may be formed in a tapered cross section. In this case, if the thickness t1 of the press-fit portion 22 is set smaller than the groove width (maximum groove width) at the opening end of the fixed groove 23 and thicker than the groove width (minimum groove width) t2 in the bottom surface 23a, FIG. As well as improving the assembly workability, rattling between the pole fixing member 18 and the support shaft 14a is eliminated, and electrical conduction between the pole fixing member 18 and the support shaft 14a is ensured. Further, as shown in FIG. 6, the processing cost is high to process the press-fitted portion 22 into a tapered shape, but the processing of the fixing groove 23 is relatively simple, which is advantageous in terms of cost.

  FIG. 8 is a side sectional view showing a method of positioning the magnet roller 14 in the thrust direction using the pole fixing member 18 and the support shaft 14a used in the developing device of the second embodiment. In order to perform positioning in the thrust direction, it is necessary to make the press-fitting amount of the press-fitting portion 22 into the fixed groove 23 constant. Therefore, for example, as shown in FIG. 8A, the protruding amount of the press-fit portion 22 is set to be equal to or less than the depth of the fixing groove 23, and the root portion of the press-fit portion 22 is inserted to the end surface 24 of the support shaft 14a. If the design is such that the position is regulated when the back surface of 18 is in contact with the end surface of the support shaft 14a, the press-fitting amount of the press-fitting portion 22 is always constant.

  Further, as shown in FIG. 8B, the protruding amount of the press-fit portion 22 is made larger than the depth of the fixing groove 23, and the position when the tip of the press-fit portion 22 is inserted to the bottom surface 23 a of the fixing groove 23 is It may be designed to be regulated. However, in the method of FIG. 8B, it is necessary to increase the dimensional accuracy of the press-fit portion 22 and the fixing groove 23 in order to increase the positioning accuracy, and it is visually confirmed that the tip of the press-fit portion 22 has been inserted to a predetermined position. It is difficult to confirm. Therefore, in consideration of component accuracy and assembly workability, the method of FIG.

  In addition, if the rotational torque of the developing roller 11 is large, the load applied to the magnet roller 14 is correspondingly increased, and the positional deviation in the rotational direction is likely to occur. This phenomenon is particularly noticeable when the developing device 21 is a two-component developing system. Therefore, as shown in FIG. 9, screw holes 25a and 25b are provided at predetermined positions of the fixing groove 23 and the press-fitting portion 22, respectively, and the support shaft 14a and the pole fixing member 18 are fixed with screws 26, so that the thrust direction and Positioning in the rotational direction can be performed more reliably.

  There are no particular restrictions on the amount of protrusion of the press-fit portion 22 and the depth of the fixing groove 23, but it is necessary to press-fit the press-fit portion 22 to a certain depth in order to increase both the rotational strength of the magnet roller 14 and the fixing strength in the thrust direction. Therefore, it is preferable to set appropriately according to the required fixed strength. Further, here, the positioning method in the thrust direction has been described by taking as an example the configuration of FIG. 5 in which the press-fitting portion 22 or the fixing groove 23 is not processed into a tapered shape, but the configuration of FIGS. 6 and 7 and the configuration of the first embodiment are described. Also in the configuration, positioning in the thrust direction can be performed in the same manner as in FIGS.

  In each of the above embodiments, the fixing groove 23 is provided so as to pass through the central axis (axial center) O of the support shaft 14a as shown in FIG. 10 (a), but as shown in FIG. 10 (b). The fixing groove 23 may be provided so as to be shifted upward or downward from the central axis O. In this case, since the vertical direction of the magnet roller 14 can be easily confirmed, there is no possibility that the mounting direction of the magnet roller 14 is wrong during assembly. However, since the length of the fixing groove 23 is shortened as the amount of deviation from the central axis O is increased, the press-fitting width of the press-fitting portion 22 is also reduced. Therefore, it is preferable to reduce the amount of deviation within a range in which the vertical direction of the magnet roller 14 can be confirmed.

  Further, in each of the above embodiments, since the press-fit portion 22 is provided in the entire width direction of the pole fixing member 18, the center portion of the press-fit portion 22 is accurately placed in the fixing groove 23 in order to arrange the magnet roller 14 with high accuracy. It is necessary to press fit. However, when the press-fitting operation is performed manually, it is difficult to position the central portion of the press-fitting portion 22, so it is preferable to provide a means for easily positioning the support shaft 14 a.

  For example, in the case of the pole fixing member 18 used in the first embodiment, as shown in FIG. 11, by marking in advance a mark 30 that displays the center portion (press-fit portion) of the press-fit portion 22, The press-fitting position to 23 can be seen at a glance, which improves work efficiency and reduces the occurrence of press-fitting mistakes. In addition, also in the pole fixing member 18 used for 2nd Embodiment, the method of marking a press-fit position can be used similarly.

  12A and 12B are a plan view and a side sectional view showing another configuration example of the pole fixing member 18 used in the developing device of the second embodiment. FIGS. 12A and 12B are views before inserting the support shaft. 12 (c) and 12 (d) show a state after the support shaft is inserted. In the present embodiment, a concave portion 22a having a width substantially equal to that of the support shaft 14a is provided in the central portion of the press-fit portion 22. In addition, a tapered portion 27 for facilitating insertion of the support shaft 14a is formed at the opening end of the recess 22a. The structure of other parts is the same as that of the second embodiment.

  Thereby, since the positioning of the pole fixing member 18 and the support shaft 14a becomes simple, the working efficiency is further improved as compared with the method of FIG. 11 in which the press-fitting position is marked. Here, in order to perform the positioning in the thrust direction, the protrusion amount e of the recess 22a is made larger than the depth of the fixed groove 23 as in FIG. 8B, and the tip of the recess 22a is the bottom surface of the fixed groove 23. Although the position is regulated when inserted up to 23a, as shown in FIG. 8 (a), the protruding amount e of the press-fit portion 22 is set to be equal to or less than the depth of the fixing groove 23, and the root portion of the press-fit portion 22 is set. It is preferable that the position of the press-fit portion 22 is regulated when it is inserted up to the end surface 24 of the support shaft 14a because it is possible to visually confirm that the tip of the press-fit portion 22 has been inserted to a predetermined position. Further, instead of forming the recess 22a, only the press-fitting position may be processed into a tapered shape.

  In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the meaning of this invention. For example, the position where the press-fit portion 22 is provided is not limited to the lower portion of the pole fixing member 18, and may be provided on the upper portion or the left and right sides. In that case, if the elongated hole 18b is formed so as to draw an arc centered on the press-fitting position, only the polar angle can be adjusted while the position of the magnet roller 14 is fixed. If fine adjustment of the polar angle is unnecessary, a normal screw hole may be provided instead of the long hole 18b.

  The present invention is not limited to a printer, and can be applied to an image forming apparatus including a one-component or two-component developing type developing device using magnetic toner, such as a digital or analog type monochrome and color copying machine, a facsimile, or the like.

  The present invention includes a housing for storing a magnetic developer, a developer carrying body that carries a developer supplied from the housing, in which a magnetic field generating member having a plurality of magnetic poles is rotatably disposed. A pole fixing member that is fixed to one end of the support shaft of the magnetic field generating member and restricts the rotation of the magnetic field generating member, and a magnetic material that is disposed opposite to the developer carrying member and restricts the amount of developer supplied onto the photosensitive drum or non-magnetic material. In a developing device including a magnetic regulating member, a fixing groove is formed on an end surface of the support shaft, and a press-fitting portion that is at least partially pressed into the fixing groove is projected from the pole fixing member. Yes.

  As a result, the support shaft of the magnetic field generating member and the pole fixing member can be firmly fixed with a simple configuration, so that the positioning of the magnetic field generating member in the rotational direction can be strictly performed, and the fluctuation of the polar angle after positioning can be changed. A developing device that can be suppressed can be provided simply and at low cost.

  In addition, the fixed groove is provided so that the end face of the spindle is divided into two parts, and the press-fitting part is pressed into the entire fixed groove, so that the play between the pole fixing member and the spindle is eliminated, and the magnetic field generating member is positioned in the rotational direction. It becomes a developing device that can perform more strictly. The press-fit portion can be formed by bending a part of a pole fixing member made of a sheet metal member into a V-shaped cross section, or bending an end of a thick pole fixing member at a substantially right angle. Further, it is possible to prevent displacement of the magnetic field generating member in the thrust direction by utilizing the elastic force of the sheet metal member.

  In the case of a press-fit portion where the end portion of the pole fixing member is bent, the press-fit operation is facilitated if either the press-fit portion or the fixing groove is formed in a tapered section. Further, if the press-fit position is marked and displayed, the press-fit position can be easily visually recognized at the time of assembly, and work efficiency is improved and work errors are reduced.

  Further, if the protruding amount of the press-fit portion and the depth of the fixing groove are set to predetermined values, the magnetic field generating member can be positioned in the thrust direction by press-fitting the press-fit portion to the limit. Further, if the press-fitting portion and the fixing groove are screw-fixed, the fixing strength in the rotational direction can be increased in addition to the positioning of the magnetic field generating member in the thrust direction.

  In addition, when a developing bias is applied via the pole fixing member, electrical conduction between the pole fixing member and the support shaft is ensured, and a stable developing bias can always be applied. The developing device can be effectively suppressed.

These are side sectional views of a printer provided with the developing device of the present invention. These are side sectional views of the developing device according to the first embodiment of the present invention. These are a side sectional view and a plan view of a support shaft and pole fixing member of a magnet roller used in the developing device of the first embodiment. These are side surface sectional views of the developing device according to the second embodiment of the present invention. These are a side sectional view and a plan view of a support shaft and pole fixing member of a magnet roller used in the developing device of the second embodiment. These are a side sectional view and a plan view showing another configuration example of a support shaft of a magnet roller and a pole fixing member used in the developing device of the second embodiment. These are a side sectional view and a plan view showing another configuration example of a support shaft of a magnet roller and a pole fixing member used in the developing device of the second embodiment. These are side surface sectional views which show the positioning method of the thrust direction of the magnet roller using the pole fixing member used for the developing device of 2nd Embodiment, and a spindle. These are side surface sectional drawings which show the positioning method of the thrust direction of the magnet roller which fixes a pole fixing member and a spindle. These are side surface sectional drawings which show the positional relationship of a fixed groove | channel and the center axis | shaft of a spindle. These are side sectional drawing and a top view which show the example which marked the press-fit position to the press-fit part of the pole fixing member. These are the top view and side sectional drawing which show the other structural example of the pole fixing member used for the image development apparatus of 2nd Embodiment. These are a top view and a front view of a conventional developing device. These are front views which show an example of the pole fixing member used for the conventional developing device. These are the front view which shows the other example of the pole fixing member used for the conventional developing device, the side sectional view which shows the state fixed to the spindle, and the front view. FIG. 16 is a side sectional view and a front view showing a state in which the pole fixing member of FIG. 15 is fixed to the support shaft (FIG. 16A) and a state in which the pole fixing member is displaced (FIG. 16B).

Explanation of symbols

5 Housing (housing)
6 Cover (housing)
7 First stirring screw 8 Second stirring screw 11 Developing roller (developer carrier)
12 Regulating blade (regulating member)
14 Magnet roller (magnetic field generating member)
14a Support shaft 18 Polar fixing member 18a D cut hole 18b Long hole 20, 26 Screw 21 Developing device 22 Press-fit portion 22a Recess 23 Fixing groove 25a, 25b Screw hole 30 Mark 41 Photosensitive drum 100 Printer O Center shaft (axial center)

Claims (14)

A housing for storing a magnetic developer, a magnetic field generating member having a plurality of magnetic poles arranged in a rotatable manner, a developer carrying member for carrying the developer supplied from the housing, and the magnetic field generation A pole fixing member that is fixed to one end of a support shaft of the member and restricts the rotation of the magnetic field generating member, and a magnetic body that is disposed opposite to the developer carrying member and restricts the amount of developer supplied onto the photosensitive drum In a developing device comprising a magnetic regulating member,
The developing device according to claim 1, wherein a fixing groove is formed on an end surface of the support shaft, and a press-fitting portion at least a part of which is press-fitted into the fixing groove is projected from the pole fixing member.   The developing device according to claim 1, wherein the pole fixing member presses the magnetic field generating member in a thrust direction by an elastic force.   The pole fixing member is provided with an arc-shaped elongated hole that becomes a part of a circumference centered on the support shaft when the press-fitting portion is press-fitted into the fixing groove. The developing device according to claim 1, wherein the developing device is fixed to the housing with screws.   The said fixed groove is provided so that the end surface of the said spindle may be divided into two, The said press-fit part is press-fit in the said fixed groove whole region, The Claim 1 thru | or 3 characterized by the above-mentioned. Development device.   The developing device according to claim 4, wherein the pole fixing member is a sheet metal member, and the press-fitting portion is formed by bending a part of the pole fixing member into a V-shaped cross section.   The developing device according to claim 4, wherein the pole fixing member is a sheet metal member having a predetermined thickness or more, and the press-fitting portion is formed by bending an end portion of the pole fixing member substantially vertically.   The developing device according to claim 6, wherein a cross-sectional shape of the press-fitting portion is tapered.   The developing device according to claim 6, wherein a cross-sectional shape of the fixing groove is tapered.   9. The developing device according to claim 5, wherein a press-fitting position is marked on the press-fitting portion.   The developing device according to claim 4, wherein the fixing groove is formed so as to be shifted from an axis of the support shaft.   The protrusion amount of the press-fitting portion is equal to or less than the depth of the fixing groove, and the electrode fixing member is press-fitted into the fixing groove until it abuts against an end surface of the support shaft. The developing device according to any one of the above.   The protrusion amount of the press-fit portion is larger than the depth of the fixed groove, and the press-fit portion is press-fitted into the fixed groove until the tip of the press-fit portion reaches the bottom surface of the fixed groove. The developing device according to any one of the above.   The screw hole is provided in the side surface of the said fixing groove and the said press-fit part, The said press-fit part is press-fitted in the said fixed groove and fixed to the screw to the position where each screw hole overlaps. The developing device according to claim 10.   The developing device according to claim 1, wherein a developing bias is applied via the pole fixing member.

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