JP5375382B2 - Developing roller, developing device, process cartridge, and image forming apparatus - Google Patents

Description

  The present invention relates to a developing roller, a developing device, a process cartridge, and an image forming apparatus used in a copying machine, a facsimile machine, a printer, and the like. More specifically, a developer carried on a developing sleeve is divided into a photosensitive drum and a developing sleeve. The present invention relates to a developing roller and a developing device which are transported to a developing area facing each other with a gap and develop a latent electrostatic image on the photosensitive drum to form a toner image. The present invention also relates to a process cartridge and an image forming apparatus having such a developing device.

  In an image forming apparatus used for a copying machine, a facsimile, a printer, or the like, a cylindrical shape in which a magnet roller and an end portion that adsorbs developer to the outer surface by a magnetic force of the magnet roller contained in the magnet roller is fixed by caulking. A developing roller (see Patent Document 1) including a developing sleeve and a flange portion that rotationally drives the developing sleeve has been proposed.

  According to the developing roller described in Patent Document 1, the flange portion includes a press-fitting portion that is press-fitted into the developing sleeve, and a rotation shaft that protrudes from the press-fitting portion that rotationally drives the developing sleeve. ing. A chamfered portion is provided at an edge of the end of the press-fitting portion near the rotation axis.

  The end portion of the developing sleeve into which the flange portion is press-fitted is caulked so as to be in close contact with the surface of the chamfered portion, and the flange portion and the developing sleeve are fixed.

  In the above-described image forming apparatus, the magnet roller, the cylindrical developing sleeve that adsorbs the developer to the outer surface by the magnetic force of the magnet roller contained in the magnet roller, and the press-fitted into the developing sleeve are fixed. In addition, a developing roller (see Patent Document 2) including a flange portion that rotationally drives the developing sleeve has been proposed.

  According to the developing roller described in Patent Document 2, the flange portion includes a press-fitting portion press-fitted into the developing sleeve, and a rotating shaft protruding from the press-fitting portion that rotationally drives the developing sleeve. ing. The press-fitting portion and the rotation shaft are positioned coaxially with each other. The press-fitting portion is formed with a large-diameter portion having an outer diameter slightly larger than the inner diameter of the developing sleeve, and an outer diameter slightly connected to the large-diameter portion and slightly smaller than the inner diameter of the developing sleeve. And a guide portion. The developing sleeve and the flange portion are fixed to each other by an elastic restoring force between the developing sleeve and the large-diameter portion of the flange portion. The outer surface of the large-diameter portion and the outer surface of the guide portion in the longitudinal section of the flange portion are provided in parallel to each other, and are also provided in parallel with the central axis of the flange portion.

  And since the said guide part is provided in the said flange part, the said developing sleeve and the said flange part are arrange | positioned coaxially.

  In the above-described image forming apparatus, the magnet roller, the cylindrical developing sleeve that adsorbs the developer to the outer surface by the magnetic force of the magnet roller contained in the magnet roller, and the adhesive that is press-fitted into the developing sleeve. There has been proposed a developing roller (see Patent Document 3) including a flange portion that rotationally drives the developing sleeve fixed by the above.

  8 and 9 are cross-sectional views of a conventional developing roller. As shown in FIGS. 8 and 9, the developing sleeve 932 includes a main body portion 951 and a press-fit receiving portion 952 connected to the main body portion 951. An inner diameter of the press-fit receiving portion 952 is slightly larger than an inner diameter of the main body portion 951.

  According to the developing roller 915 described in Patent Document 3, the flange portion 940 protrudes from a press-fit portion 944 that is press-fitted into the developing sleeve 932 and the press-fit portion 944 that rotationally drives the developing sleeve 932. The rotation shaft 942 is provided. The press-fit portion 944 and the rotation shaft 942 are arranged coaxially with each other. The press-fit portion 944 is provided with a plurality of groove portions 944 a extending in parallel with the longitudinal direction of the flange portion 940. The plurality of groove portions 944 a are provided at intervals in the circumferential direction of the press-fit portion 944. An anaerobic adhesive is applied to the groove 944a after the press-fitting portion 944 is press-fitted into the developing sleeve 932.

  When the flange portion 940 is press-fitted into the developing sleeve 932, the press-fitting portion 944 of the flange portion 940 is fixed to the press-fitting receiving portion 952 of the developing sleeve 932. At this time, the inner diameter of the press-fit receiving portion 952 and the outer diameter of the press-fit portion 944 are formed to be the same size, and the inner peripheral surface of the press-fit receiving portion 952 and the press-fit portion 944 are formed. It overlaps with the outer peripheral surface without gaps.

  The difference in inner diameter between the main body portion 951 and the press-fitting receiving portion 952 of the developing sleeve 932 is larger than the axial dimension of the groove portion 944a of the press-fit portion 944 (that is, the depth of the groove portion 944a). Has been. When the anaerobic adhesive is applied to the groove portion 944a, the anaerobic adhesive enters the inner surface of the press-fit receiving portion 952, so that the flange portion is fixed (that is, fixed) to the developing sleeve 932. However, since the anaerobic adhesive does not penetrate into the inner surface of the main body 951, the developing sleeve 932 is fixed to the developing sleeve 932 without fixing the developing sleeve 932 and the magnet roller. The magnet roller becomes rotatable. As described above, the flange portion 140 is fixed (ie, fixed) to the developing sleeve 932.

  However, the developing roller 915 described in Patent Documents 1 to 3 has the following problems.

  That is, in the developing roller described in Patent Document 1, since the flange portion is fixed by caulking along the surface of the chamfered portion of the developing sleeve, the developing sleeve, the flange portion, There is a problem that it is difficult to arrange the two coaxially.

  In addition, since the developing sleeve and the flange portion are fixed to the developing roller described in Patent Document 2 only by an elastic restoring force between the developing sleeve and the flange portion, the rotation shaft rotates. As a result, when the developing roller is rotated, there is a problem that the flange portion is removed from the developing sleeve or the developing roller is idle.

  Further, in order to rotate the developing roller regularly, it is necessary that the developing sleeve and the flange portion are arranged coaxially with each other and that the developing sleeve and the flange portion are firmly fixed to each other. In addition, since the developing sleeve is formed with high accuracy and the flange portion press-fitted into the developing sleeve also needs to be formed with high accuracy, the developing sleeve and the flange portion are manufactured. There was a problem that the manufacturing cost was high. The “high accuracy” means that a dimensional error is relatively small in this specification.

  Further, as shown in FIGS. 8 and 9, the developing roller 915 described in Patent Document 3 has the following problems. That is, since the anaerobic adhesive used after the flange portion 940 is press-fitted into the developing sleeve 932 requires time to cure, the developing roller 915 in a state where the anaerobic adhesive is cured is stored. There was a problem that a place to do was necessary.

  In addition, when using the anaerobic adhesive in a high-temperature and high-humidity environment, the moisture contained in the air during the curing has an adverse effect on the adhesive surface, so the adhesive force is reduced, The adhesive force between the developing sleeve 932 and the flange portion 940 is weakened, and when the developing roller is rotated, the flange portion 940 may be removed from the developing sleeve 932 or may be idle. Therefore, in order to securely fix the flange portion 940 to the developing sleeve 932, in addition to the need for a storage place, it is necessary to prepare equipment for keeping the temperature and humidity of the storage place constant. There was a problem.

  The present invention aims to solve this problem.

  That is, the present invention relates to a developing roller, a developing device, a process cartridge including the developing device, and an image forming apparatus that prevent the occurrence of periodic image density unevenness caused by the inclination of the flange portion that fixes the developing sleeve. The purpose is to provide.

The invention described in claim 1 is a magnet roller, a cylindrical developing sleeve that adsorbs developer on the outer surface by the magnetic force of the magnet roller contained in the magnet roller, and press-fitted into the developing sleeve. In a developing roller having a flange portion that is fixed to the developing sleeve with an adhesive and that rotationally drives the developing sleeve.
The flange portion includes a straight portion which is press-fitted into the developing sleeve, a tapered portion coated with instant adhesive, are provided,
An outer diameter of the straight portion is formed slightly larger than an inner diameter of the developing sleeve;
The developing roller according to claim 1, wherein an outer diameter of the tapered portion is gradually decreased toward the inner side of the developing sleeve.

The invention described in claim 2 is the invention described in claim 1, wherein the flange portion is provided with a large-diameter portion between the straight portion and the tapered portion. The diameter is slightly larger than the outer diameter of the straight portion, and the difference between the outer diameter size of the large diameter portion and the inner diameter size of the developing sleeve is 0.05 mm or less. It is what.

According to a third aspect of the present invention, in the first or second aspect of the present invention, an adhesive reservoir groove is provided on the inner peripheral surface of the developing sleeve facing the tapered portion. It is what.

  The invention described in claim 4 is the invention according to any one of claims 1 to 3, wherein the flange portion is formed by forging.

  According to a fifth aspect of the present invention, in the invention having a developing roller having a developing sleeve that adsorbs a developer on an outer surface, the developing roller according to any one of the first to fourth aspects. A developing device having a developing roller.

  The invention described in claim 6 is a process cartridge characterized in that, in the invention having at least a developing device, the developing device according to claim 5 is provided as the developing device.

  The invention described in claim 7 is characterized in that, in the invention having at least a photosensitive drum, a charging device, and a developing device, the developing device according to claim 6 is provided as the developing device. The image forming apparatus.

According to the invention described in claim 1, the flange portion, gradually accordance provided tapered portions coated with instantaneous adhesive, and the outer diameter of the front Symbol tapered portion, toward the back side of the developing sleeve Therefore, it is possible to provide a developing roller that prevents the occurrence of periodic image density unevenness caused by the inclination of the flange portion that fixes the developing sleeve.

  Further, when the flange portion is press-fitted into the developing sleeve, the tapered portion of the flange portion serves as a guide and is press-fitted into the developing sleeve, so that the flange portion is not inclined to the developing sleeve. can do. That is, it is possible to provide a developing roller in which the developing sleeve and the flange portion are arranged coaxially.

  When the flange portion is press-fitted into the developing sleeve, the tapered portion forms a slight gap between the inner surface of the developing sleeve and the outer surface of the tapered portion. The gap can allow a dimensional error of the inner surface of the developing sleeve and allow a dimensional error of the flange portion. For this reason, the developing roller having the developing sleeve and the flange portion can be provided at low cost.

According to a second aspect of the present invention, the flange portion is provided with a large-diameter portion that is continuous with the side away from the tip portion of the tapered portion, and the outer diameter of the large-diameter portion is the inner diameter of the developing sleeve. The difference between the outer diameter of the large diameter portion and the inner diameter of the developing sleeve is 0.05 mm or less. For this reason, when the flange portion is press-fitted into the developing sleeve, the flange portion can be disposed on the developing sleeve without being tilted by uniformly deforming the developing sleeve. That is, it is possible to provide a developing roller in which the developing sleeve and the flange portion are arranged coaxially.

According to the third aspect of the present invention, an adhesive reservoir groove for applying the instantaneous adhesive is provided on the inner peripheral surface of the developing sleeve facing the tapered portion. For this reason, before the flange portion is press-fitted into the developing sleeve, a sufficient amount of the instantaneous adhesive is supplied to the tapered portion by applying the instantaneous adhesive to the adhesive reservoir groove in advance. it can. Thus, it is possible to provide a developing roller in which the developing sleeve and the flange portion are more firmly fixed.

  According to invention of Claim 4, the said flange part is formed by the forge process. In this way, the developing roller formed by forging the flange portion can be provided at a lower cost than a developing roller formed by zinc die casting.

  According to the fifth aspect of the present invention, there is provided a developing device that has the developing roller described above, and prevents the occurrence of periodic image density unevenness caused by the inclination of the flange portion that fixes the developing sleeve. Can do.

  Since the invention according to claim 6 has the developing device according to claim 5, there is provided a process cartridge that prevents occurrence of periodic image density unevenness caused by inclination of the flange portion for fixing the developing sleeve. Can be provided.

  Since the invention described in claim 7 has the developing device described in claim 6, the developing device prevents occurrence of periodic image density unevenness caused by the inclination of the flange portion for fixing the developing sleeve. An image forming apparatus having a photosensitive drum and a charging device can be provided.

It is sectional drawing of the developing roller which shows one embodiment of this invention. FIG. 2 is a partially enlarged explanatory view of the developing roller shown in FIG. 1. It is explanatory drawing which shows the state which measures the axial collapse dimension of the developing roller which shows one embodiment of this invention. It is sectional drawing of the developing roller concerning other one Embodiment. It is a graph which shows the relationship between the press-fitting allowance at the time of press-fitting a flange part in a developing sleeve, and the axis | shaft collapse dimension of a flange part. It is a graph which shows the relationship between the pressure input at the time of press-fitting a flange part in a developing sleeve, and the axis | shaft tilting dimension of a flange part. It is sectional drawing of the process cartridge which shows one embodiment of this invention. 1 is an explanatory diagram viewed from the front of a configuration of an image forming apparatus having a process cartridge according to an embodiment of the present invention. It is sectional drawing of the conventional developing roller. It is sectional drawing which follows the IV-IV line | wire in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<Developing rollers 115 and 225>
1 to 4, reference numerals 115 and 215 denote developing rollers. The developing rollers 115 and 215 include a magnet roller 133, cylindrical developing sleeves 132 and 232 that adsorb the developer on the outer surface by the magnetic force of the magnet roller 133 contained in the magnet roller 133, and the developing sleeve 132, And a flange portion 140 that is press-fitted into the H.232 and is fixed to the developing sleeves 132 and 232 with an instantaneous adhesive to rotate the developing sleeves 132 and 232. In the developing rollers 115 and 215, (a) the flange portion 140 is provided with a taper portion 148 covered with an instantaneous adhesive, and (b) the outer diameter of the taper portion 148 is equal to the developing sleeve 132. 232 is gradually formed smaller toward the back side.

  As described above, the magnet roller 133, the cylindrical developing sleeves 132 and 232 that adsorb the developer to the outer surface by the magnetic force of the magnet roller 133 contained in the magnet roller 133, and the press fit into the developing sleeves 132 and 232. Development rollers 115 and 215 having a flange portion 140 that rotates and drives the development sleeves 132 and 232 fixed to the development sleeves 132 and 232 with an adhesive. Is provided with a tapered portion 148 covered with an instantaneous adhesive, and (b) the outer diameter of the tapered portion 148 is gradually formed smaller toward the inner side of the developing sleeves 132 and 232. The periodicity caused by the inclination of the flange 140 that fixes the developing sleeves 132 and 232 It is possible to provide a developing roller 115, 215 which prevents the occurrence of image density unevenness. Further, when the flange portion 140 is press-fitted into the developing sleeves 132 and 232, the tapered portion 148 of the flange portion 140 serves as a guide and is press-fitted into the developing sleeves 132 and 232. 140 can be placed without tilting. That is, it is possible to provide the developing rollers 115 and 215 in which the developing sleeves 132 and 232 and the flange portion 140 are arranged coaxially. Further, when the flange portion 140 is press-fitted into the developing sleeves 132 and 232, the tapered portion 148 forms a slight gap between the inner surface of the developing sleeves 132 and 232 and the outer surface of the tapered portion 148. Since this gap allows a dimensional error of the inner surface of the developing sleeves 132 and 232 and a dimensional error of the flange portion 140, the developing roller 115 having the developing sleeves 132 and 232 and the flange portion 140, 215 can be provided at low cost.

  In the present invention, preferably, an adhesive reservoir groove 150 is provided on the inner peripheral surface of the developing sleeve 232 facing the tapered portion 148. As described above, when the adhesive reservoir groove 150 for storing the instantaneous adhesive is provided on the inner peripheral surface of the developing sleeve 232 facing the tapered portion 148, the instantaneous adhesive is removed from the adhesive reservoir groove. Then, a flange portion is press-fitted into the developing sleeve 232, so that a sufficient amount of instantaneous adhesive can be applied to the tapered portion 148. In this way, it is possible to provide the developing roller 215 in which the developing sleeve 232 and the flange portion 140 are more firmly fixed.

  In the present invention, preferably, the flange portion 140 is provided with a large-diameter portion 146 connected to a side away from the tip end portion of the tapered portion 148, and the outer diameter of the large-diameter portion 146 is set to the developing sleeve. 132, and the difference between the outer diameter of the large-diameter portion 146 and the inner diameter of the developing sleeve 132 is 0.05 mm or less. When press-fitting, the developing sleeve 132 is uniformly deformed. Therefore, the flange portion 140 can be disposed on the developing sleeve 132 without being inclined. That is, it is possible to provide the developing roller 115 in which the developing sleeve 132 and the flange portion 140 are arranged coaxially.

  In the present invention, preferably, the flange portion 140 is formed by forging. As described above, when the flange portion 140 is formed by forging, the developing roller 115 can be provided at a lower cost than the developing roller 115 formed by zinc die casting.

  Next, the developing roller 115 of the present invention will be described in detail.

  As shown in FIGS. 1 and 2, the developing roller 115 includes a cored bar 134, a cylindrical magnet roller (also referred to as a magnet body) 133, and the magnet roller 133 attached to the cored bar 134. Is controlled to move along the longitudinal direction of the metal core 134, a cylindrical developing sleeve 132, and a flange portion 140 that is fixed to the developing sleeve 132 and rotationally drives the developing sleeve 132. , A drive pin 143 attached to the flange part 140, and a slide bearing 145 positioned between the flange part 140 and the cored bar 134 and rotatably attached to the cored bar 134. The core bar 134 is provided such that the longitudinal direction thereof is parallel to the longitudinal direction of the photosensitive drum 108 described later. One end in the longitudinal direction of the metal core 134 is rotatably attached to the flange portion 140, and the other end is fixed to the case 125 described later without rotating. The magnet roller 133 is made of a magnetic material, and is fixed to the outer periphery of the cored bar 134 without rotating around the axis. A plurality of fixed magnetic poles (not shown) are attached to the magnet roller 133, and the plurality of fixed magnetic poles are long and rod-shaped magnets, and the magnet roller 133, that is, the longitudinal direction of the developing roller 115 Along the entire length. One fixed magnetic pole of the plurality of fixed magnetic poles is provided opposite to a stirring screw 118 described later, and forms a pumping magnetic pole. Since this fixed magnetic pole generates a magnetic force on the outer surface of the developing sleeve 132, that is, the developing roller 115, the developer in the second space 121 of the storage tank 117 described later is applied to the outer surface of the developing sleeve 132. Adsorbed. The other fixed magnetic pole of the plurality of fixed magnetic poles is provided to face a photosensitive drum 108 to be described later and forms a developing magnetic pole. The fixed magnetic pole generates a magnetic force on the outer surface of the developing sleeve 132, that is, the developing roller 115. Therefore, a magnetic field is formed between the developing sleeve 132 and a photosensitive drum 108 to be described later. As a result, a magnetic brush is formed by the magnetic field, so that the developer toner adsorbed on the outer surface of the developing sleeve 132 is transferred to the photosensitive drum 108 described later. At least one other fixed magnetic pole is provided between the pumping magnetic pole and the developing magnetic pole. The fixed magnetic pole generates a magnetic force on the outer surface of the developing sleeve 132, that is, the developing roller 115. Therefore, the fixed magnetic pole conveys the developer toward the photosensitive drum 108 to be described later, and the developed developer will be described later. It is transported from the photosensitive drum 108 into a storage tank 117 described later.

  When the fixed magnetic pole adsorbs the developer on the outer surface of the developing sleeve 132, a plurality of magnetic particles of the developer are stacked along the magnetic lines of force generated by the fixed magnetic pole. Standing (standing) on the outer surface of 132. As described above, a state in which a plurality of the magnetic particles are erected on the outer surface of the developing sleeve 132 along the magnetic field lines is “the magnetic particles“ rise ”on the outer surface of the developing sleeve”. The toner particles are attracted to the raised magnetic particles, ie, the developer is attracted to the outer surface of the developing sleeve 132 by the magnetic force of the magnet roller 133. It becomes.

  The developing sleeve 132 includes (accommodates) a magnet roller 133 and is provided so as to be rotatable around the axis of the developing sleeve 132, so that the inner peripheral surface thereof is sequentially opposed to the fixed magnetic pole. To be rotated. The developing sleeve 132 is made of an aluminum alloy (A6063). This aluminum alloy is excellent in terms of workability and lightness. The developing sleeve 132 may be made of a nonmagnetic material such as brass, stainless steel (SUS), or conductive resin other than the aluminum alloy. The developing sleeve 132 includes a main body 151 and a press-fit receiving portion 152 that is continuous with the main body 151. The press-fit receiving part 152 is opposed to a press-fit part 144 of the flange part 140 described later. The inner diameter of the press-fit receiving portion 152 is slightly larger than the inner diameter of the main body 151, and the inner diameter dimension of the press-fit receiving portion 152 is, for example, 16.8 mm. In the axial section of the developing sleeve 132, the inner surface of the main body 151 and the inner surface of the press-fit receiving portion 152 are provided in parallel, and the central shaft 132A of the developing sleeve 132 (see FIG. 3). (See also). The axial length of the developing sleeve 132 is preferably about 300 mm to 350 mm.

  The flange portion 140 includes a press-fit portion 144 that is press-fitted into the developing sleeve 132, and a rotating shaft 142 that rotationally drives the developing sleeve 132. The flange portion 140 is formed by zinc die casting of a stainless steel (SUS) shaft insert in which the press-fit portion 144 is made of zinc and the rotating shaft 142 is made of SUS303. Of course, the press-fit portion 144 and the rotary shaft 142 are positioned coaxially. The press-fit portion 144 is formed in a columnar shape as a whole. The press-fit portion 144 includes a straight portion 146, a large-diameter portion 146 connected to the back side of the developing sleeve 132 of the straight portion 146, and a tapered portion 148 connected to the back side of the developing sleeve 132 of the large-diameter portion 146. And are provided. The outer diameter of the straight portion 146 is slightly larger than the inner diameter of the press-fit receiving portion 152 of the developing sleeve 132, and the outer diameter of the straight portion 146 is, for example, 16.85 mm. In the longitudinal section of the flange portion 140, the outer surface of the straight portion 146 and the central axis 140A of the flange portion 140 are provided in parallel. The outer diameter of the large diameter portion 147 is slightly larger than the inner diameter of the press-fitting receiving portion 152 of the developing sleeve 132, and the outer diameter of the large diameter portion 147 is, for example, 16.88 mm. ing. The tapered portion 148 has an outer diameter that gradually decreases from the large-diameter portion 147 toward the back side of the developing sleeve 132, and a tip portion 148a on the side away from the large-diameter portion 147. The outer diameter dimension (shown in FIG. 2) is, for example, 16.75 mm. That is, the taper portion 148 is formed in a straight line in the longitudinal section of the flange portion 140, and approaches the central axis 140 </ b> A of the flange portion 140 toward the back side of the developing sleeve 132. The angle θ1 (see FIG. 2) formed by the central axis 140A and the outer surface of the tapered portion 148 is formed at a time. After the instantaneous adhesive is applied to the taper portion 148, the flange portion 140 is pressed into the developing sleeve 132. That is, an instantaneous adhesive is applied to the tapered portion 148 in advance before the flange portion 140 is press-fitted into the developing sleeve 132. The smaller the angle θ1, the longer the dimension in the longitudinal direction of the tapered portion 148 becomes. Therefore, it is preferable to increase the adhesive force between the flange portion 140 and the developing sleeve 132. However, the tapered portion 148 is preferable. When the longitudinal dimension of the flange portion 140 becomes longer, the time for press-fitting the flange portion 140 into the developing sleeve 132 is prolonged, so that the instantaneous adhesive starts to harden while the flange portion 140 is being press-fitted. Occurs. Therefore, the angle θ1 is preferably about 0.5 to 3 degrees.

  The instant adhesive is a cyanoacrylate adhesive, but other known instant adhesives may be used as long as they do not contradict the purpose of the present invention. The rotating shaft 142 is formed in a columnar shape having an outer diameter smaller than that of the press-fit portion 144 and protrudes from the press-fit portion 144. The drive pin 143 is formed in an annular shape, and the rotation shaft 142 is passed through a through hole provided in the center, and is attached to the rotation shaft 142 without rotating. By rotating the drive pin 143, the developing sleeve 132 fixed (that is, fixed) to the flange portion 140 rotates around the axis.

  Next, the developing roller 215 of the present invention will be described in detail.

  As shown in FIG. 4, the developing roller 215 includes a cored bar 134, a cylindrical magnet roller (also referred to as a magnet body) 133, and a magnet roller 133 attached to the cored bar 134. An E-ring 141 that restricts movement along the longitudinal direction, a cylindrical developing sleeve 232, and a flange portion 140 that is fixed to the developing sleeve 232 and rotates the developing sleeve 232 are provided. In the developing roller 215, the same portions as those of the developing roller 115 described above are denoted by the same reference numerals. The developing sleeve 232 includes a main body portion 151 and a press-fit receiving portion 152 connected to the main body portion 151. When the flange portion 140 is press-fitted into the developing sleeve 232, the press-fit receiving portion 152 is provided to be opposed to the press-fit portion 144 (that is, the tapered portion 148) of the flange portion 140. The press-fit receiving portion 152 is provided with an adhesive reservoir groove 150 for storing the instantaneous adhesive. In this way, the adhesive reservoir groove 150 provided at a position opposite to the press-fit portion 144 (that is, the taper portion 148) is formed in a concave shape on the inner peripheral surface of the press-fit receiving portion 152, and on the entire circumference thereof. It extends over. When the flange portion 140 is press-fitted into the developing sleeve 232 after the instantaneous adhesive is stored in the adhesive reservoir groove 150, a sufficient amount of the instantaneous adhesive is applied to the press-fit portion 144 (that is, the taper portion 148). Can be applied. In this way, it is possible to provide the developing roller 215 in which the developing sleeve 232 and the flange portion 140 are more firmly fixed.

<About the developing device 113>
As shown in FIG. 7, the developing device 113 of the present invention includes developing rollers 115 and 215 having developing sleeves 132 and 232 that adsorb the developer on the outer surface. As described above, since the developing device 113 includes the developing rollers 115 and 215, development that prevents the occurrence of periodic image density unevenness caused by the inclination of the flange portion 140 that fixes the developing sleeves 132 and 232 is prevented. An apparatus 113 can be provided.

  Next, the developing device 113 of the present invention will be described in detail.

  As shown in FIG. 7, the developing device 113 includes a developer supply unit 114, a case 125, developing rollers 115 and 215 as developer carriers, a doctor blade 116 as a regulating member, and a receiving member. And a member 149. The developer supply unit 114 includes a storage tank 117, a toner replenishment unit 139, and a pair of stirring screws 118 as stirring members. The storage tank 117 is formed in a box shape whose length is substantially the same as the photosensitive drum 108 described later, and a partition wall 119 extending along the longitudinal direction of the storage tank 117 is formed in the storage tank 117. Is provided. The partition wall 119 defines the first space 120 and the second space 121 in the storage tank 117, and both end portions of the first space 120 and the second space 121 communicate with each other. Yes. Such a storage tank 117 stores the developer described later in both the first space 120 and the second space 121. The toner replenishing portion 139 is provided in the vicinity of the storage tank 117. Each toner supply unit 139 is supplied with toner of each color from toner bottles 135Y, 135M, 135C, and 135K, which will be described later. The stirring screw 118 is housed in each of the first space 120 and the second space 121. The longitudinal direction of the stirring screw 118 is parallel to the longitudinal direction of the storage tank 117, the developing rollers 115 and 215, and the photosensitive drum 108 described later. The agitating screw 118 is provided so as to be rotatable around an axis, and the developer and the magnetic particles are agitated by rotating around the axis, and a developer is fed along the axis. Transport. That is, the agitating screw 118 accommodated in the first space 120 conveys the developer from the one end to the other end, and the agitating screw 118 accommodated in the second space 121 The developer is conveyed from the other end toward the one end.

  The developer includes toner and magnetic particles (also referred to as a magnetic carrier). The toner is appropriately replenished from a toner replenishing unit 139 described later to one end of only the first space 120 on the side of the first space 120 and the second space 121 far from the developing rollers 115 and 215. Is done. The toner is a spherical fine particle produced by an emulsion polymerization method or a suspension polymerization method, but the toner is obtained by pulverizing a lump composed of a synthetic resin mixed and dispersed with various dyes or pigments. It may be formed by pulverization or the like. Such a toner has a volume average particle diameter of 3 μm or more and 7 μm or less. In addition, the magnetic particles contain a spherical core material composed of ferrite as a magnetic material, a resin component obtained by crosslinking a thermoplastic resin such as acrylic and a melamine resin, and a charge control agent, and A resin coat film covering the outer surface of the core material and spherical alumina particles dispersed in the resin coat film are provided. The volume average particle size of the magnetic particles is 20 μm or more and 50 μm or less. The said core material is comprised with the ferrite as a magnetic material, and is formed in the spherical form. The resin coat film covers the entire outer surface of the core material. Since the resin coat film contains a resin component obtained by crosslinking a thermoplastic resin such as acrylic and a melamine resin, and a charge control agent, the resin coat film has elasticity and strong adhesive force, and the alumina particles Holding. Further, since the alumina particles are formed in a spherical shape whose outer diameter is larger than the thickness of the resin coat film, the alumina particles protrude from the resin coat film to the outer peripheral side of the magnetic particles. By using the toner and the magnetic particles having such a small particle diameter, the developing device 113 can improve image reproducibility and obtain a high-quality image. Further, if the volume average particle size of the magnetic particles is less than 20 μm, the magnitude of magnetization of each magnetic particle becomes small, so that the magnetic binding force from the developing rollers 115 and 215 becomes weak. This is not desirable because the magnetic particles are likely to be attracted to the photosensitive drum 108 described later. When the volume average particle diameter of the magnetic particles exceeds 50 μm, the electric field between the magnetic particles and an electrostatic latent image on the photosensitive drum 108 described later becomes sparse, and a uniform image can be obtained. Is not desirable (ie, the image quality deteriorates), which is not desirable.

  According to the above-described configuration, the developer supply unit 114 conveys the toner supplied to the one end of the first space 120 and the magnetic particles to the other end while stirring the other, Transport from the end to the other end of the second space 121. The developer supplying unit 114 agitates the toner and the magnetic particles in the second space 121 and supplies them to the outer surfaces of the developing rollers 115 and 215 while transporting them in the axial direction.

  The case 125 is formed in a box shape, is attached to the storage tank 117 of the developer supply unit 114, and covers the development rollers 115 and 215 together with the storage tank 117. An opening 125 a is provided in a portion of the case 125 that faces a photosensitive drum 108 described later. Further, the doctor blade 116 is attached to the case 125 in a state of being spaced from the outer surface of the developing sleeve 132 (hereinafter referred to as a doctor gap S), so that the doctor blade 116 has a desired thickness. The developer on the outer surface of the developing sleeve 132 exceeding the thickness is scraped into the storage tank 117, and the developer on the outer surface of the developing sleeve 132 conveyed to the developing region 131 described later is desired. Make it thick. The receiving member 149 is provided on the upstream side of the doctor blade 116 in the rotation direction of the developing sleeve 132, and the receiving member 149 and the doctor blade 116 are closely connected via an elastic member (not shown). It is piled up. The receiving member 149 is formed in a substantially right triangle. One top of the receiving member 149 is positioned toward the outer surface of the developing sleeves 132 and 232, and the other top is the case. 125 is supported. The receiving member 149 is positioned at the same distance (that is, an interval) as the interval (that is, the doctor gap S) between the doctor blade 116 and the outer surfaces of the developing sleeves 132 and 232. Alternatively, the receiving member 149 may be closer to the outer surface of the developing sleeves 132 and 232 than the distance between the doctor blade 116 and the outer surfaces of the developing sleeves 132 and 232 (that is, the doctor gap S). . The cylindrical developing rollers 115 and 215 are provided between the second space 121 and the photosensitive drum 108 and in the vicinity of the opening 125a. It is provided in parallel with both the storage tank 117. The developing rollers 115 and 215 are spaced apart from a photosensitive drum 108 to be described later, and the space between the developing rollers 115 and 215 and the photosensitive drum 108 to be described later is a space of the developer. A developing region 131 is obtained in which the toner is attracted to a photosensitive drum 108 (to be described later) to develop an electrostatic latent image to obtain a toner image. In the developing area 131, the developing rollers 115 and 215 and a photosensitive drum 108 described later face each other.

  In the developing device 113 having such a configuration, the developer is sufficiently stirred by the developer supply unit 114, and the stirred developer is adsorbed to the outer surfaces of the developing sleeves 132 and 232 by a fixed magnetic pole. In the developing device 113, the developing sleeves 132 and 232 rotate to convey the developer adsorbed by the plurality of fixed magnetic poles toward the developing region 131. The developing device 113 adsorbs the developer having a desired thickness by the doctor blade 116 to the photosensitive drum 108 described later. In this way, the developing device 113 carries the developer on the developing rollers 115 and 215, conveys the developer to the developing area 131, develops an electrostatic latent image on the photosensitive drum 108 described later, and forms a toner image. Form. Thereafter, the developing device 113 releases the developed developer toward the storage tank 117. Further, the developed developer stored in the storage tank 117 is sufficiently stirred again with another developer in the second space 121, and an electrostatic latent image on the photosensitive drum 108 described later is formed. Used for development. The developing device 113 detects a toner supply control device (not shown) when a toner concentration sensor (described later) detects that the concentration of toner supplied to the photosensitive drum 108 (described later) has decreased, for example. Is operated, and toner is supplied from the toner replenishing portion 139 to the storage tank 117.

  According to the present invention described above, the developing device 113 includes the receiving member 149. Since the receiving member 149 is provided on the upstream side in the rotation direction of the developing sleeves 132 and 232 of the doctor blade 116, the toner pressure applied to the doctor gap S is reduced and the displacement of the doctor gap S is suppressed. The variation in the toner supplied to the photosensitive drum 108 is extremely reduced. In this way, it is possible to provide the developing device 113 that can reduce the variation of the developer on the developing rollers 115 and 215 due to the displacement of the doctor gap S and obtain a good image without unevenness in image density. As the developing device 113, a toner having a sphericity of 0.93 or more can be used. That is, it is known to reduce the toner particle size in order to improve the image quality of the image. However, in the case of reducing the particle size, the particle size distribution becomes broad in the conventional pulverized toner. Since it is difficult to handle, a method that can increase the circularity of the toner by a polymerization method or the like, and can achieve high image quality with a sharp particle size distribution has become common. However, when the circularity of the toner is increased, the toner approaches a spherical shape, so that cleaning becomes very difficult. However, the receiving member 149 is provided, and the photosensitive drum 108 described later due to the displacement of the doctor gap S is provided. Therefore, the cleaning performance can be maintained even when spherical toner obtained by polymerization or the like is used. The toner was obtained by dispersing a toner composition comprising at least a prepolymer, a colorant, and a release agent in an aqueous medium in the presence of resin fine particles, and subjecting the toner composition to a polyaddition reaction. Polymerized toner is used. By using such a toner, there are no pulverization steps, resources can be reduced, particle size distribution and charge distribution can be sharpened, and shape control that changes circularity can be easily performed. Can be obtained. The magnetic particles have a resin coat film on the core material as a magnetic material, and the resin coat film is charged to a resin component obtained by crosslinking a thermoplastic resin such as acrylic and a melamine resin. It contains a regulator. By using such magnetic particles, the impact can be absorbed and suppressed, and the effect of holding large particles with strong adhesive force can be balanced with the effect of preventing impact on the resin coat film and cleaning spent materials. Therefore, it is possible to prevent the magnetic particles from having a long life, that is, film scraping and spent.

<About Process Cartridges 106Y, 106M, 106C, 106K>
As shown in FIG. 7, the process cartridges 106 </ b> Y, 106 </ b> M, 106 </ b> C, 106 </ b> K have at least the developing device 113. Thus, when the process cartridges 106Y, 106M, 106C, and 106K have the developing device 113 having the developing rollers 115 and 215, the inclination of the flange portion 140 that fixes the developing sleeves 132 and 232 is caused. It is possible to provide process cartridges 106Y, 106M, 106C, and 106K that prevent the occurrence of periodic image density unevenness.

  Next, the process cartridges 106Y, 106M, 106C, and 106K of the present invention will be described in detail.

  As shown in FIG. 7, the process cartridges 106Y, 106M, 106C, and 106K include a cartridge case 111, a charging roller 109 as a charging device, a photosensitive drum 108, and a cleaning blade 112 as a cleaning device. , A developing device 113. That is, the process cartridges 106Y, 106M, 106C, and 106K include at least the developing device 113. The cartridge case 111 is detachable from the apparatus main body 102 to be described later, and accommodates the charging roller 109, the photosensitive drum 108, the cleaning blade 112, and the developing device 113. Further, the charging roller 109 uniformly charges the outer surface of the photosensitive drum 108. The photosensitive drum 108 is arranged at a distance from the developing rollers 115 and 215 of the developing device 113, and is formed in a columnar shape or a cylindrical shape that is rotatable about its axis. Then, an electrostatic latent image is formed on the outer surface of the photosensitive drum 108 by each laser writing unit 122 described later. Such a photosensitive drum 108 is formed on the outer surface, and transfers a toner image obtained by attracting and developing toner to the electrostatic latent image to be carried onto a transfer belt 129 described later. The toner images formed on the respective photosensitive drums 108 are sequentially superimposed on a transfer belt 129 described later, and a color image is formed on the transfer belt 129 described later. The cleaning blade 112 removes transfer residual toner remaining on the outer surface of the photosensitive drum 108 after transferring the toner image to the recording paper 107. The process cartridges 106Y, 106M, 106C, and 106K are provided between a transfer unit 104, which will be described later, and a laser writing unit 122, which will be described later. The process cartridges 106Y, 106M, 106C, and 106K are provided in the apparatus main body 102. It is detachable. The process cartridges 106Y, 106M, 106C, and 106K are arranged side by side along the conveyance direction of the recording paper 107.

<Regarding Image Forming Apparatus 101>
As shown in FIG. 8, the image forming apparatus 101 includes at least the photosensitive drum 108, the charging roller 109 as a charging device, and the developing device 113. As described above, when the image forming apparatus 101 includes the developing device 113 including the developing rollers 115 and 215, a periodic image generated by the inclination of the flange portion 140 that fixes the developing sleeves 132 and 232. It is possible to provide the image forming apparatus 101 that prevents the occurrence of density unevenness.

  Next, the image forming apparatus 101 of the present invention will be described in detail.

  As shown in FIG. 8, the image forming apparatus 101 has an apparatus main body 102, a paper feed unit 103, a registration roller pair 110, a transfer unit 104, a fixing unit 105, and laser writing as an optical unit. The unit 122 includes a plurality of process cartridges 106Y, 106M, 106C, and 106K, and a plurality of toner bottles 135Y, 135M, 135C, and 135K. Therefore, the image forming apparatus 101 includes at least a charging roller 109 as a charging device, a photosensitive drum 108, and a developing device 113. Note that an image forming apparatus 101 such as a copying machine, a printer, or a facsimile using an electrophotographic system generates an image of each color of yellow (Y), magenta (M), cyan (C), and black (K), that is, a color image. And formed on a recording sheet 107 (shown in FIG. 8) as a single transfer material. The apparatus main body 102 is formed in a box shape, for example, and is installed on a floor or the like. The apparatus main body 102 includes a paper feeding unit 103, a registration roller pair 110, a transfer unit 104, a fixing unit 105, a laser writing unit 122, a plurality of process cartridges 106Y, 106M, 106C, and 106K, and a plurality of them. Toner bottles 135Y, 135M, 135C, and 135K. A plurality of the paper feeding units 103 are provided in the lower part of the apparatus main body 102. The paper feed unit 103 is provided with a paper feed cassette 123 that can accommodate the recording paper 107 in an overlapping manner and can be taken in and out of the apparatus main body 102 and a paper feed roller 124. When the paper feeding roller 124 is pressed against the uppermost recording paper 107 in the paper feeding cassette 123, the uppermost recording paper 107 is transferred to a transfer belt 129 (to be described later) of a transfer unit 104 (to be described later) and to be described later. To the secondary transfer roller 137. The registration roller pair 110 is provided in a conveyance path of the recording paper 107 conveyed from the paper supply unit 103 to the transfer unit 104 described later, and includes a pair of rollers 110a and 110b. Such a registration roller pair 110 sandwiches a recording sheet 107 between a pair of rollers 110a and 110b, and a transfer belt 129 (to be described later) of the transfer unit 104 at a timing at which the sandwiched recording sheet 107 can be superimposed on a toner image. Then, the toner is fed to a secondary transfer roller 137 described later.

  The transfer unit 104 is provided above the paper feed unit 103. The transfer unit 104 includes a driving roller 127, a driven roller 128, a transfer belt 129 as an image carrier, primary transfer rollers 130Y, 130M, 130C, and 130K, a secondary transfer roller 137, and a transfer belt cleaning unit. 136. The drive roller 127 is disposed on the upstream side in the conveyance direction of the recording paper 107 and is driven to rotate by a motor or the like as a drive source. The driven roller 128 is rotatably supported by the apparatus main body 102 and is disposed on the downstream side in the conveyance direction of the recording paper 107. The transfer belt 129 is configured with a resin film or rubber as a base. The transfer belt 129 is formed in an endless annular shape, is stretched over both the drive roller 127 and the driven roller 128, and the drive roller 127 is rotated to drive the transfer roller 127. Circulation around the driven roller 128 counterclockwise in the figure (endless running). The primary transfer rollers 130Y, 130M, 130C, and 130K are formed on the photosensitive drums 108 with the transfer belt 129 sandwiched between the photosensitive drums 108 of the process cartridges 106Y, 106M, 106C, and 106K. The image is transferred to the transfer belt 129. Further, the secondary transfer roller 137 transfers the toner image formed on the transfer belt 129 to the recording paper 107 with the recording paper 107 on the transfer belt 129 sandwiched between the transfer belt 129. . Then, the transfer unit 104 sends the recording paper 107 onto which the toner image has been transferred toward the fixing unit 105. Further, since the transfer belt cleaning unit 136 is provided upstream of the process cartridges 106Y, 106M, 106C, and 106K in the transfer direction of the transfer belt 129, the residual toner on the transfer belt 129 is collected, The toner is conveyed to a waste toner collection bottle described later.

  Further, the fixing unit 105 includes a pair of rollers 105a and 105b that sandwich the recording paper 107 between them, so that the recording paper 107 fed from the transfer unit 104 is pressed between the pair of rollers 105a and 105b. By heating, the toner image transferred from the transfer belt 129 onto the recording paper 107 is fixed on the recording paper 107. The fixing unit 105 is provided on the downstream side of the transfer unit 104 in the transport direction of the recording paper 107, and sends out the recording paper 107 onto which the toner image has been transferred toward the paper discharge roller pair 138. The paper discharge roller pair 138 sends the recording paper 107 to a paper discharge tray 102 a provided on the upper part of the apparatus main body 102. The laser writing unit 122 is attached above the paper feeding unit 103. The laser writing unit 122 corresponds to each of the process cartridges 106Y, 106M, 106C, and 106K. Each laser writing unit 122 irradiates the outer surface of the photosensitive drum 108 uniformly charged by the charging roller 109 of the process cartridges 106Y, 106M, 106C, and 106K with laser light to form an electrostatic latent image. To do. The plurality of toner bottles 135Y, 135M, 135C, and 135K are provided above the process cartridges 106Y, 106M, 106C, and 106K, and the toner bottles 135Y, 135M, 135C, and 135K include the toners. Each color toner to be supplied to the supply unit 139 is stored. The toner bottles 135Y, 135M, 135C, and 135K are detachable from the apparatus main body 102.

  The image forming apparatus 101 having such a configuration forms an image on the recording paper 107 as described below. First, the image forming apparatus 101 rotates the photosensitive drum 108 and uniformly charges the outer surface of the photosensitive drum 108 to −700 V by the charging roller 109. The outer surface of the photosensitive drum 108 is irradiated with laser light to expose the photosensitive drum 108, the image portion is attenuated to −150 V, and an electrostatic latent image is formed on the outer surface of the photosensitive drum 108. Form. When the electrostatic latent image is positioned in the developing area 131, a developing bias voltage of −550 V is applied to the electrostatic latent image and is attracted to the outer surfaces of the developing sleeves 132 and 232 of the developing device 113. The developer is attracted to the outer surface of the photosensitive drum 108 to develop the electrostatic latent image, and a toner image is formed on the outer surface of the photosensitive drum 108. The photosensitive drum 108 transfers the toner image thus obtained onto the transfer belt 129. The image forming apparatus 101 transfers the recording sheet 107 conveyed by the sheet feeding roller 124 of the sheet feeding unit 103 between the pair of rollers 110a and 110b between the transfer belt 129 and the secondary transfer roller 137. The toner image formed on the transfer belt 129 is transferred to the recording paper 107. Then, the image forming apparatus 101 fixes the toner image on the recording paper 107 by the fixing unit 105 and forms a color image on the recording paper 107. On the other hand, the toner remaining on the photosensitive drum 108 without being transferred is stored in a waste toner collection bottle (not shown) by the cleaning blade 112. The waste toner collection bottle is detachable from the apparatus main body 102 so that it can be replaced when the storage amount is full. The photosensitive drum 108 from which the residual toner has been removed is initialized by a neutralizing lamp (not shown) and provided for the next image forming process. In the image forming apparatus 101, process control is performed in order to suppress fluctuations in image quality due to environmental fluctuations and fluctuations with time. Specifically, first, the developing ability in the developing device 113 is detected. For example, an image of a certain toner pattern is formed on the photosensitive drum 108 under a condition where the developing bias voltage is constant, the image density is detected by an optical sensor (not shown), and the developing ability is grasped from the density change. Then, the image quality can be kept constant by changing the target value of the toner density so that the developing ability meets the predetermined target developing ability. For example, when the image density of the toner pattern detected by the optical sensor is lower than the target development density, the CPU as a control means (not shown) operates the toner supply control device so as to increase the toner density. Toner is supplied from the tank 117. Here, the toner density is detected by a toner density sensor (not shown). Note that the image density of the toner pattern formed on the photoconductive drum 108 may vary somewhat due to the influence of uneven image density period due to the developing sleeves 132 and 232.

  Further, the image forming apparatus 101 may be provided with a toner bottle that is detachable from the apparatus main body 102. In this case, since each toner bottle can be attached to and detached from each developing device 113 individually from the apparatus main body 102, each toner bottle and each developing device 113 can be individually replaced, and unnecessary replacement is not performed. Therefore, the user's expense at the time of parts replacement can be reduced. In addition, since the number of times of opening / closing and taking in / out other parts of the image forming apparatus 101 is reduced, toner scattering can be prevented and maintenance can be improved. In the image forming apparatus 101, the process cartridges 106Y, 106M, 106C, and 106K include a cartridge case 111, a charging roller 109, a photosensitive drum 108, a cleaning blade 112, and a developing device 113. ing. However, in the present invention, the process cartridges 106Y, 106M, 106C, and 106K only need to include at least the developing device 113, and the cartridge case 111, the charging roller 109, the photosensitive drum 108, and the cleaning blade 112 are not necessarily included. It does not have to be provided. In the above-described embodiment, the image forming apparatus 101 includes process cartridges 106Y, 106M, 106C, and 106K that are detachable from the apparatus main body 102. However, in the present invention, the image forming apparatus 101 only needs to include the developing device 113 and does not necessarily include the process cartridges 106Y, 106M, 106C, and 106K.

  The present invention is not limited to the embodiment described above. That is, various modifications can be made without departing from the scope of the present invention.

Example 1
The inner diameter dimension of the press-fitting receiving part of the developing sleeve including the magnet roller was 16.8 mm. Next, the angle of the taper portion in the longitudinal section of the flange portion formed by Zn die casting is set to 1 degree, the outer diameter of the large diameter portion of the flange portion is set to 16.88 mm, and the flange portion The outer diameter of the tip was 16.75 mm. Thus, by setting the outer diameter of the large diameter portion to 16.88 mm and the inner diameter of the press-fit receiving portion to 16.8 mm, the outer diameter size of the large-diameter portion (that is, the flange portion) and the press-fit receiver The difference (hereinafter referred to as press-fitting allowance) from the inner diameter of the portion (that is, the developing sleeve) was 0.08 mm. Then, after holding the flange portion using a commercially available press-fitting device, the taper portion is coated (coated) with a cyanoacrylate-based instantaneous adhesive, and the flange portion is press-fitted into the developing sleeve, thereby developing roller. Got.

(Example 2)
A developing roller was obtained in the same manner as in Example 1 except that an adhesive reservoir groove was formed on the inner peripheral surface of the press-fitting receiving portion of the developing sleeve.

(Example 3)
The adhesive reservoir groove is formed on the inner peripheral surface of the press-fitting receiving portion of the developing sleeve, and the outer diameter of the large-diameter portion of the flange portion is 16.85 mm, and the tip portion of the flange portion A developing roller was obtained in the same manner as in Example 1 except that the outer diameter of the toner was 16.75 mm and the press-fitting allowance was 0.05 mm.

Example 4
The adhesive reservoir groove is formed on the inner peripheral surface of the press-fitting receiving portion of the developing sleeve, and the outer diameter of the large-diameter portion of the flange portion is 16.85 mm, and the tip portion of the flange portion The outer diameter of each was 16.75 mm and the press-fitting allowance was 0.05 mm. A developing roller was obtained in the same manner as in Example 1 except that the flange portion was made of an aluminum alloy and formed by forging.

(Comparative Example 1)
The outer diameter of the large diameter portion of the flange portion and the outer diameter size of the tip portion of the flange portion were 16.88 mm. That is, the angle of the taper portion was set to 0 degree. A developing roller was obtained in the same manner as in Example 1 except that the taper portion was not coated (applied) with a cyanoacrylate instantaneous adhesive unlike Example 1 described above.

(Comparative Example 2)
The outer diameter of the large-diameter portion of the flange portion and the outer diameter size of the tip portion of the flange portion were 16.77 mm. That is, the angle of the tapered portion was set to 0 degree, and the press-fitting allowance was set to zero (that is, the press-fitting allowance was not provided). A developing roller was obtained in the same manner as in Example 1 except that the taper portion was coated (coated) with an acrylic anaerobic adhesive.

  As described above, when the flange portion is press-fitted into the developing sleeve of the developing roller obtained in Example 1, the pressure input when the flange portion is press-fitted into the developing sleeve is variously changed. “Fall dimension” was measured. The measurement results are shown in FIG. Next, a plurality of flange portions with various changes in the press-fitting allowance of the developing roller obtained in Example 1 were manufactured, and the plurality of flange portions with various changes in the size of the press-fitting allowance were press-fitted into the developing sleeve. At that time, the “shaft collapse dimension” described later was measured. When press-fitting, a commercially available press-fitting device with a press input set at 600 N was used. The measurement results are shown in FIG.

  As shown in FIG. 3, the “axis tilting dimension A” is a vertical direction between the center axis 132A of the developing sleeve 132 and the center point 140R of the base end portion away from the tip end portion 148a of the flange portion 140. Means the unit (micrometer). When the center axis 132A of the developing sleeve 132 and the center point 140R of the base end portion of the flange portion 140 overlap (that is, when the axis tilting dimension A is zero), the developing sleeve 132 and the flange portion 140 are arranged coaxially. Will be. (That is, the flange portion 140 is fixed to the developing sleeve 132 without tilting.)

  FIG. 5 shows the relationship between the axis collapse dimension and the pressure input. In FIG. 5, the vertical axis indicates the above-described axis collapse dimension, and the horizontal axis indicates the pressure input when the flange portion is press-fitted into the developing sleeve. From FIG. 5, it can be seen that when the pressure input when the flange portion is press-fitted exceeds 600 N, the axis collapse dimension increases. For this reason, it has been found that when the flange portion is press-fitted into the developing sleeve, it is optimal to press-fit with a pressure input of about 600 N.

  FIG. 6 shows the relationship between the axis collapse dimension and the press-fitting allowance. In FIG. 6, the vertical axis represents the average value of the axis collapse dimensions when 50 flange portions formed with the same press-fitting allowance are press-fitted 50 times into 50 developing sleeves, respectively. The horizontal axis indicates the size of the press-fitting allowance when the flange portion is press-fitted into the developing sleeve. From FIG. 6, it can be seen that when the press-fitting allowance when the flange portion is press-fitted exceeds 0.05 mm, the shaft collapse dimension increases. For this reason, it has been found that it is optimal that the press-fitting allowance of the developing roller be 0.05 mm or less.

  Next, the developing rollers obtained in Example 1 to Example 4 or Comparative Examples 1 and 2 were incorporated into an image forming apparatus, and runout accuracy, torque resistance, and manufacturing cost were evaluated. The evaluation results are shown in the following Table 1. The evaluation criteria in Table 1 are ○ for those that can withstand practical use, ◎ for excellent materials, and × for those that cannot withstand practical use.

  Table 1 shows the following. That is, each developing roller of Examples 1 to 4 has an angle of a taper portion of 1 degree, and the taper portion is coated (coated) with a cyanoacrylate instantaneous adhesive. As compared with the developing rollers of Comparative Examples 1 and 2 described above, it can be confirmed that the developing rollers of Examples 1 to 4 can withstand practical use in terms of manufacturing cost, runout accuracy, and torque resistance. It was. In each of the developing rollers according to the second to fourth embodiments, an adhesive reservoir groove is provided on the inner peripheral surface of the developing sleeve. Compared with the developing rollers of Example 1 and Comparative Examples 1 to 2 in which the adhesive reservoir groove is not formed, the developing rollers of Examples 2 to 4 in which the adhesive reservoir groove is formed are It was confirmed that the deflection accuracy and torque resistance were excellent. In each of the developing rollers of Examples 3 to 4, the press-fitting allowance is set to 0.05 mm (that is, 0.05 mm or less). Compared to the developing rollers of Examples 1 to 2 and Comparative Examples 1 to 2 described above, Examples 3 to 4 have a press-fitting allowance of 0.05 mm (that is, 0.05 mm or less). This developing roller was confirmed to be particularly excellent in manufacturing cost, runout accuracy, and torque resistance. In the developing roller of Example 4, the flange portion is made of an aluminum alloy and is formed by forging. Compared to the developing rollers of Examples 1 to 3 and Comparative Examples 1 to 2 described above, the developing roller of Example 4 in which the flange portion is made of an aluminum alloy and formed by forging is as follows. It was confirmed that the manufacturing cost was excellent (that is, it could be manufactured at a low cost).

101 Image forming apparatus 106Y, 106M, 106C, 106K Process cartridge 108 Photosensitive drum 109 Charging roller (charging device)
113 Developing device 115, 215 Developing roller 132, 232 Developing sleeve 133 Magnet roller 140 Flange part 147 Large diameter part 148 Taper part 150 Adhesive collecting groove

JP-A-11-153129 JP-A-6-102754 JP 2000-19848 A

Claims (7)

A magnet roller, a cylindrical developing sleeve that adsorbs developer to the outer surface by the magnetic force of the magnet roller contained in the magnet roller, and press-fitted into the developing sleeve and fixed to the developing sleeve with an adhesive A developing roller having a flange portion for rotating the developing sleeve;
The flange portion includes a straight portion which is press-fitted into the developing sleeve, a tapered portion coated with instant adhesive, are provided,
An outer diameter of the straight portion is formed slightly larger than an inner diameter of the developing sleeve;
The developing roller according to claim 1, wherein an outer diameter of the tapered portion is gradually reduced toward the inner side of the developing sleeve. The flange portion is provided with a large-diameter portion between the straight portion and the tapered portion, the outer diameter of the large-diameter portion is formed slightly larger than the outer diameter of the straight portion, and The developing roller according to claim 1, wherein a difference between an outer diameter of the large diameter portion and an inner diameter of the developing sleeve is 0.05 mm or less . The developing roller according to claim 1 or claim 2, characterized in that the inner peripheral surface opposing the developing sleeve to said tapered portion, a groove adhesive reservoir is provided.   The developing roller according to any one of claims 1 to 3, wherein the flange portion is formed by forging.   A developing device having a developing roller having a developing sleeve that adsorbs developer on an outer surface, wherein the developing roller includes the developing roller according to any one of claims 1 to 4. A developing device.   6. A process cartridge having at least a developing device, wherein the developing device includes the developing device according to claim 5.   An image forming apparatus having at least a photosensitive drum, a charging device, and a developing device, wherein the developing device includes the developing device according to claim 6.

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