JP4227541B2 - Development unit and process cartridge - Google Patents

Description

  The present invention relates to a developing unit and a process cartridge that can be attached to and detached from an electrophotographic image forming apparatus employing an electrophotographic system such as a laser printer or a copying machine. Here, the electrophotographic image forming apparatus forms an image on a recording medium using an electrophotographic image forming system. Examples of the electrophotographic image forming apparatus include an electrophotographic copying machine, an electrophotographic printer (for example, a laser beam printer, an LED printer, etc.), a facsimile machine, a word processor, and the like. The developing unit is a unit in which a toner housing frame containing developer (toner) and a developing frame containing developing means are joined together, or the toner containing portion and the developing means are integrated. The developing frame body and the lid member are integrated with each other, and are detachable from the main body of the image forming apparatus.

  The process cartridge is a cartridge in which the developing means, the charging means or the cleaning means and the electrophotographic photosensitive member are integrated, and the cartridge can be attached to and detached from the image forming apparatus main body.

  2. Description of the Related Art Conventionally, in an electrophotographic image forming apparatus using an electrophotographic image forming process, an electrophotographic photosensitive drum (hereinafter referred to as a photosensitive drum) and process means acting on the photosensitive drum are integrally formed into a cartridge. A process cartridge system is employed in which the printer is detachably attached to the main body of the electrophotographic image forming apparatus. In such a process cartridge system, the photosensitive drum and at least one of the charging unit, the developing unit, and the cleaning unit or at least the developing unit are integrally formed into a cartridge, and the cartridge is attached to the main body of the electrophotographic image forming apparatus. There are things that can be attached and detached.

  According to this type of process cartridge system, the maintenance of the apparatus can be performed by the user himself / herself without depending on the service person, so that the operability can be remarkably improved. Therefore, this process cartridge system is widely used in electrophotographic image forming apparatuses.

  Generally, a process cartridge will be described with reference to FIGS. 7 to 9. A cleaning frame 10 integrally supporting a photosensitive drum 7, a charging roller 4, and a cleaning blade 6 a; a developing roller 5 a and a developing blade The developing frame body 8 and the lid frame body 9 integrally support a toner storage portion 8a that stores 5b and a developer (hereinafter referred to as toner). In some cases, the developing frame and the toner frame containing the toner are integrally joined.

  Further, as shown in FIG. 9, the developing unit D includes developing means such as a developing roller 5a and a developing blade 5b, and a developing frame 8 and a toner frame containing them, or a side surface of one of the frames. It is composed of a developing roller bearing 13 that supports the developing roller 5a at both ends, side covers 11 and 12 that cover a drive gear train (not shown), and the like. The developing unit D may be a part of the process cartridge, and the developing unit D may be detachable from the electrophotographic image forming apparatus independently.

  As fixing means for the above-described frame and other parts, screws, heat caulking, resin bonding (fixing by injection of molten resin) or the like is generally used. In addition, as a component fixing means, a joining technique such as hot melt or ultrasonic welding is employed (for example, see Patent Document 1).

  Next, the terpene compound will be described.

  A terpene compound is a main component of an essential oil obtained mainly by steam distillation of plants, and is generally known to be usable as a fragrance.

  On the other hand, terpene compounds are also known for uses other than those described above. For example, d-limonene, which is a monoterpene, has a molecular structure that is very similar to styrene, and has the property of dissolving polystyrene at room temperature. It is used as a shrinking agent for expanded polystyrene (for example, see Patent Document 2).

  In addition, using an additive containing limonene, the surface of the joint resin is dissolved, and the joint resin surface is stirred by applying heat in the dissolved state, and the joint resin is fused to the target in that state. Technology has also been proposed (see, for example, Patent Document 3).

Japanese Patent Laid-Open No. 10-20744 JP-A-5-263065 JP 2002-20703 A

  The conventional joining technique has the following problems. 9 and 4 showing the developing unit D and FIG. 7 showing a schematic cross section of the process cartridge will be described. 4 is a perspective view of the developing unit D showing a state immediately before the side covers 11 and 12 and the developing roller driving gear 5d on both sides are attached to the developing unit D. FIG.

  In the developing unit D described above, the developing roller 5a is supported by the developing roller bearing member 13 as shown in FIG. The developing roller bearing member 13 has a plurality of holes 13a for fitting to the positioning portion 11a of the side cover, and the developing frame 8 is also provided with a plurality of holes 8d at the same position. . The side cover positioning portion 11a engages with the hole portion 13a of the developing roller bearing member 13 and the hole portion 8d of the developing device frame, and these three parts are assembled. Therefore, the developing roller bearing member 13 is sandwiched and supported by the developing frame 8 and the side cover 11. The opposite side cover 12 and developing roller bearing member 14 are also assembled in the same configuration.

  Further, as shown in FIG. 7 showing a schematic cross section of the process cartridge, development is performed by an arm portion 11b extending from the developing frame 8 or the side cover 11 and a shaft member 10a for attaching the arm portion 11b to the cleaning frame 10. The unit D is supported so as to be rotatable with respect to the cleaning frame 10. A pressure member 16 such as a coil spring is provided between the cleaning frame 10 and the development unit D, and presses the development unit D, that is, the development roller 5a toward the photosensitive drum 7. Since the developing roller 5a is pressurized toward the photosensitive drum 7, the distance between the developing roller 5a and the photosensitive drum 7 is kept constant.

  Here, when the toner amount stored in the developing unit D is increased, it is expected that the pressing force of the developing roller 5a toward the photosensitive drum 7 increases and the driving torque of the developing unit D increases. The pressing force presses the developing roller 5a through the arm portion 11b, the developing frame 8, the side cover positioning portion 11a, and the developing roller bearing member 13. Therefore, the pressurizing force and the torque increase during driving cause deflection and twist of these parts. In particular, if the strength of the positioning portion 11a of the side cover that determines the position of the developing roller 5a is insufficient, the positioning accuracy may be lowered. Even in this case, in order to obtain a stable image quality, it is necessary to improve the strength and positioning accuracy of the developing roller bearing member 13 or the positioning member 11a of the side cover that supports the developing roller bearing member 13. May come. In order to improve the strength, there is a method of increasing the shaft diameter of the positioning member 11a or changing the frame material, but the shaft diameter is increased from the viewpoint of space saving of the image forming apparatus main body. It is not preferable that the outer shape of the process cartridge becomes large. In addition, the change to the high-rigidity material is disadvantageous in terms of cost in consideration of productivity.

  In order to improve rigidity and positioning accuracy, the periphery of the positioning member 11a of the side cover is joined to the developing frame 8 in an annular shape (or arc shape) according to the shape thereof, and the positioning member 11a of the side cover and the developing frame are joined. It is ideal that the body 8 is integrated with the body 8, but in the conventional method, for example, resin bonding by injection of molten resin, injection of hot melt, adhesive, etc., a ring around the positioning member 11 a of the side cover In the case of joining the side cover 11 and the developing frame body 8 by joining them in an arc shape, in the case of molten resin injection or hot melt injection, the injection material is heated to a high temperature in order to melt the injection material. Or a high pressure is required to inject a high-viscosity product. To must be enlarged joint portion (the shaft), that space is a problem that becomes necessary. Therefore, in the conventional configuration, the developing frame 8 is not joined in an annular shape (or arc shape) around the positioning member 11a of the side cover. In the joining by the resin joining or hot melt injection, or the fixing 11c by screws, The joint position is provided at a position where the outer shape of the developing frame and the side cover does not increase and the clearance with the drive gear train 15 included therein can be maintained. That is, since there is a position restriction (space restriction), the side cover 11 is often fixed or joined at a location 11c away from the developing roller bearing member 13, and in a state where the pressure is applied as described above. Since the possibility of being easily affected by the deflection of the positioning portion 11a of the side cover remained, further measures were desired.

  It is an object of the present invention to minimize the enlargement of the outer shape of the side cover positioning part 11a and the side cover 11, to develop the developing roller bearing member 13 with high positioning accuracy and strong development rigidity of the developing roller bearing member 13. To provide a unit and a process cartridge.

A first invention according to the present application includes a developing unit having an image carrier,
A first developing frame formed of a styrenic resin composition containing the developing means;
Having one end side of the first developing frame and a plurality of second frames formed of a styrene resin composition sandwiching the side surface on the other end side;
The first developing frame and the second frame each have a plurality of positioning portions for positioning the second frame relative to the first developing frame,
The second frame supports a support member that supports the image carrier,
The support member is supported by the positioning portion of the second frame body, and the first frame body and the second frame are assembled when the first developing frame body and the second frame body are assembled. Sandwiched and assembled with the body,
At least one of the positioning portions has a joint surface that joins the first developing frame and the second frame,
At least one of the first developing frame and the second frame has an injection port for injecting a terpene solvent, and at least one of the first developing frame and the second frame Are provided with recesses, slits or chamfers for forming a flow path communicating with the inlet, and the terpene solvent is supplied to at least a part of the joint surface before welding and fixing through the flow path. Is composed of
The supply of the terpene solvent to the first flow path from the inlet to the vicinity of the joint surface, the second flow path from the first flow path to the joint surface, or both of the flow paths utilizes the capillary phenomenon. In the development unit,
The entrance of the positioning part on the first developing frame side, which is engaged with the positioning part of the second frame body, forms a space for blocking the supply of the terpene solvent due to capillary action. Development unit.

  A second invention according to the present application is the development unit, wherein the support member is made of a material different from that of the first development frame body and the second frame body.

A third invention according to the present application is a process cartridge that is attachable to and detachable from an electrophotographic image forming apparatus.
An electrophotographic photoreceptor, and developing means for developing the latent image formed on the electrophotographic photoreceptor using toner,
The developing means has an image carrier,
A first developing frame formed of a styrenic resin composition containing the developing means;
Having one end side of the first developing frame and a plurality of second frames formed of a styrene resin composition sandwiching the side surface on the other end side;
The first developing frame and the second frame each have a plurality of positioning portions for positioning the second frame relative to the first developing frame,
The second frame supports a support member that supports the image carrier,
The support member is supported by the positioning portion of the second frame body, and the first frame body and the second frame are assembled when the first developing frame body and the second frame body are assembled. Sandwiched and assembled with the body,
At least one of the positioning portions has a joint surface that joins the first developing frame and the second frame,
At least one of the first developing frame and the second frame has an injection port for injecting a terpene solvent, and at least one of the first developing frame and the second frame Are provided with recesses, slits or chamfers for forming a flow path communicating with the inlet, and the terpene solvent is supplied to at least a part of the joint surface before welding and fixing through the flow path. Is composed of
The supply of the terpene solvent to the first flow path from the inlet to the vicinity of the joint surface, the second flow path from the first flow path to the joint surface, or both of the flow paths utilizes a capillary phenomenon. ,
The entrance of the positioning part on the first developing frame side, which is engaged with the positioning part of the second frame body, forms a space for blocking the supply of the terpene solvent due to capillary action. Process cartridge.

  A fourth invention according to the present application is the process cartridge, wherein the support member is made of a material different from that of the first developing frame and the second frame.

  According to the present invention, a developing unit having a highly rigid and rigid engaging portion by joining the engaging portion between the positioning shaft of the side cover made of styrene resin and the developing frame body with a terpene solvent. And a cartridge can be provided.

  As an image forming apparatus according to the first embodiment applicable to the present invention, an example used in a laser printer will be described.

  FIG. 6 is a sectional view of the image forming apparatus 1 according to the first embodiment applicable to the present invention. The image forming apparatus 1 emits a laser L based on the obtained image information by the scanner 2 and irradiates the photosensitive drum 7 built in the process cartridge 3 with the laser L. A latent image is formed on the photosensitive drum 7, and the latent image is developed with toner by the process cartridge 3.

  On the other hand, the recording sheets S stacked on the recording sheet stacking plate 52 are fed one by one while being separated one by one by the sheet feeding roller 53 and the separation pad 54, and further downstream by the intermediate roller 55 and the conveying roller 56. The transfer roller 51 transfers a visible image of the toner formed on the photosensitive drum 7 onto the conveyed recording sheet S.

  Then, the recording paper S on which the unfixed toner image is formed is conveyed further downstream, and the toner image is fixed by a fixing device 57 having a heat source therein, and then passes through an intermediate paper discharge roller 58. The paper is discharged out of the apparatus by a discharge roller 59.

  The process cartridge 3 here includes a photosensitive drum 7 and at least one process means. As the process means, for example, the charging roller 4 for charging the photosensitive drum 7, the developing means 5 for developing the latent image formed on the photosensitive drum 7, the developing frame 8 for storing the developing means 5, or the toner is stored. There are a toner storage portion 8a, a lid member 9, cleaning means 6 for cleaning toner remaining on the surface of the photosensitive drum 7, a cleaning frame 10, and the like. The process cartridge 3 applicable to the present invention includes a cleaning unit C that rotatably supports a photosensitive drum 7 on a cleaning frame 10, a cleaning unit 6 and a charging roller 4 incorporated therein, and a developing unit D described later. Has been.

  The configuration of the developing unit D of the process cartridge 3 that can be applied to the present invention will be described.

  The development unit D includes a toner storage portion 8a that stores toner, a toner transport member 8b that transports the toner to the development roller 5a, and a development frame 8 that stores the development means 5 including the development roller 5a and the development blade 5b. (FIGS. 7 and 9).

  In addition, the developing frame body 8 and the toner storage portion 8a, or one of the side surfaces thereof, are configured by side covers 11 and 12 that cover the driving gear train 15 that drives the developing roller 5a and the toner conveying member 8b (FIG. 4). ).

  The side covers 11 and 12 have positioning shafts 11a and 12a for positioning the developing roller 5a, and the positioning shaft engages with a hole 8d provided in the developing device frame 8, thereby developing the side cover. Positioning with respect to the frame is also performed.

  The developing roller 5a includes a fixed magnet (not shown), and spacer members 17 for maintaining a space between the developing roller 5a and the photosensitive drum 7 are assembled at both ends in the longitudinal direction of the developing roller 5a. Further, developing roller bearing members 13 and 14 for supporting the developing roller 5a are assembled at both longitudinal ends of the developing roller 5a. The developing roller 5a is supported by the side cover 11 by engaging the holes 13a, 14a of the developing roller bearing members 13, 14 with the positioning shaft 11a of the side cover. As shown in FIG. 4, when the developing roller bearing members 13 and 14 are sandwiched between the developing frame 8 and the side covers 11 and 12, the position of the developing roller 5a in the developing unit D is determined. .

  The side covers 11 and 12 have arm portions 11b and 12b in which coupling holes for pivoting the developing unit D to the cleaning unit C are formed. Further, in order to maintain a gap between the developing unit D and the cleaning unit C, a predetermined pressing force is applied by a pressing member 16 such as a spring.

  The pressure is applied to the developing roller 5a, the bearing members 13 and 14 that support the developing roller 5a, the side cover positioning shafts 11a and 12a that support the bearing member, and the relationship between the positioning shafts 11a and 12a and the developing device frame 8. It extends to the joint.

  Here, when the amount of toner in the developing unit D increases, the weight of the developing unit D also increases, so the pressurizing force also increases. When the applied pressure increases, the engagement portion is deflected and twisted when a driving torque is applied. In addition, an increase in weight causes an increase in impact during transportation. Various measures against these are required.

  One countermeasure is to reduce the pressure applied by the pressure member 16 described above. When the toner is gradually consumed and the weight of the developing unit D is gradually reduced, the developing roller driving gear 5d and the photosensitive drum 7 are reduced. Therefore, it is necessary to pressurize appropriately even in a state where the amount of toner is small, and it is not preferable to simply reduce the applied pressure.

  Therefore, in the present embodiment, it is proposed to improve the strength at the engaging portion. However, simply increasing the shaft diameter of the engaging portion is not preferable from the viewpoint of space saving, and the configuration for improving the strength at the engaging portion using another method will be described next. .

  First, the joining of the developing frame and the side cover will be described below.

  The developing frame 8 is provided with a concave portion for positioning a side cover 11 (12: opposite side cover, the description is omitted because of the same configuration), and a round hole portion 8d having a diameter of 4.6 mm in this embodiment. The side cover 11 side is also provided with a convex portion, which is a round shaft portion 11a having a diameter of 4.6 mm in this embodiment.

  As shown in FIG. 5, when the round shaft portion 11a and the round hole portion 8d are fitted, it becomes the center of rotation in the arrow Y direction shown in FIG. 5, and the round shaft portion 11a2 and the elongated round hole portion 8d2 are fitted. By doing so, the rotation posture of the developing frame 8 and the side cover 11 is determined. Further, since the positioning in the longitudinal direction is configured by sandwiching the developing roller bearing member 13 between the developing frame 8 and the side cover 11 as shown in FIG. 4, the entrance end face of the round hole 8d of the developing frame 8 8d3 (FIG. 2) and one of the end surfaces of the developing roller bearing member 13, the other end surface of the developing roller bearing member, and the base surface 11a2 (FIG. 3) of the round shaft portion 11a of the side cover abut each other. Yes. The round shaft portion 11a2 has the same configuration.

  In order to fix the conventional side cover 11 and the developing frame 8, a screw fixing as shown in FIG. 8 or a resin bonding part (injecting molten resin between two parts), in addition to the positioning part (engaging part) described above. The portion where the engaging portion of the developing roller bearing member 13 and the side cover 11 are fixed with screws or resin is the position of other components including the drive gear train 15. It is installed away from the relationship. In addition, the engaging portion is merely fitted into the hole portion with a small gap and is not completely fixed in the axial direction, so it should be applied to the arm portion 11b of the side cover. When the force increases, there is a possibility that the round shaft portion 11a of the side cover and the round hole portion 8d of the developing device frame 8 are deformed in the engaging portion, or the side cover 11 is slightly moved in the outward direction of the developing device frame. was there.

  In the present embodiment, the engagement portion between the round shaft portion 11a provided on the side cover 11 and the round hole portion 8d of the developing frame body is configured as the joining surface 20, and the terpene solvent is applied to the joining surface 20. It joins by injecting. When the engaging portion (joining surface) is completely joined and fixed, the strength of the engaging portion (developing roller bearing portion) is improved and the positional accuracy is improved.

  Next, the flow path for injecting the terpene solvent to the bonding surface 20 will be described.

  The positioning shaft 11a of the side cover and the hole 8d of the developing device frame to be engaged are in a fitting relationship. The gap between the shaft and the hole is about 5 to 50 μm. This engaging portion becomes the joint surface 20.

  The side cover positioning shaft 11a as an injection port for injecting the terpene solvent from the injector 31 is provided with a hole portion 21 penetrating from the outside to the center of the shaft. The hole 21 is substantially tapered. The hole diameter is set to a size that allows the solvent to flow from the outside to the shaft tip by capillary action. In this embodiment, the entrance has a diameter of about 2 mm and the back has a diameter of about 1.2 mm.

  Further, the distal end 23 of the positioning shaft is provided with a slit portion 22 having a width of about 0.6 mm as a first flow path for supplying a terpene solvent to the joining surface 20 (FIG. 1).

  Here, when the terpene solvent Q is dropped by the nozzle of the injector 31, the terpene solvent Q flows into the distal end portion 23 by capillary action as indicated by an arrow 40. Next, as shown by an arrow 41, the slit portion 22 at the tip portion flows in the same manner by capillary action. Next, as described above, the joint surface 20 has a minute gap between the shaft portion and the hole portion due to the fitting relationship, so that it becomes a second flow path, and the terpene-based solvent Q is caused by capillary action as indicated by an arrow 42. Spreads over the entire joint surface.

In addition, when the solvent that has passed through the flow path spreads over the entire bonding surface, if the gap between the bonding components is large, it is difficult to supply the terpene solvent to the bonding surface 20 using the capillary phenomenon. The surfaces to be joined are strongly pressed (contact pressure is about 20 g / cm ² ), and even when the contact strength is high, the capillary phenomenon hardly occurs and the supply of the terpene solvent becomes difficult. Therefore, it is preferable that the parts to be joined are close or lightly in contact with each other, or a minute unevenness is provided on at least one of the joining surfaces, and a minute space is provided at the contact part so that the solvent spreads by capillary action. This is also a preferred form.

The unevenness is, for example, a texture, and the depth is preferably 20 to 40 μm in average (Rz). When the depth exceeds 40 μm, the joints of the embossed valley portion are insufficiently joined to the mating part, and thus the joint strength tends to decrease as a whole. When the depth of the embossing is 20 to 40 μm, even if a weight of 150 g / cm ² is applied, a decrease in the bonding strength is hardly observed.

  In addition, when joining using a terpene solvent, it takes some time until the two parts are finally joined (for example, when d-limonene is used as a solvent, several minutes to several tens of minutes). Min), if necessary, by performing screw fixing 11c as described above, or by providing a resin joint N (bonded by injecting molten resin between two parts) and joining, Before the two parts are completely bonded by the terpene solvent, it is possible to prevent the bonded portion from peeling off.

  Next, the terpene solvent used for joining the engaging portion between the side cover and the developing device frame will be described.

  Examples of the terpene solvent used for the bonding (welding) include d-limonene, l-limonene, dl-limonene, d-α-pinene, d-β-pinene, α-terpinene, β-terpinene, and γ- Examples include terpinene, terpinolene, 2-carene, d-3-carene, l-3-carene, and ferrandlene. Among these, d-limonene, l-limonene or dl-limonene is preferably used, and d-limonene is particularly preferably used. Since d-limonene has a viscosity of approximately 0.98 cP at 25 ° C. and is substantially equal to water, it can be supplied by capillary action that penetrates a minute space as described above.

  As the terpene solvent, one obtained by dissolving polystyrene in a terpene solvent in advance may be used. If polystyrene is dissolved by about 10% by mass, the bonding (welding) strength is almost the same as that of the terpene solvent alone, but when dissolved in a large amount, the viscosity of the solvent is low. It tends to rise and the capillary action is less likely to occur.

  Further, when a mixed solution with other materials, for example, a mixed solution of IPA (isopropyl alcohol) and d-limonene is used, the time until the two parts are completely bonded can be shortened.

  In the present invention, a very small amount of terpene solvent (about 0.01 ml) is used and dissolves only the surface layer of the frame and other parts to be joined. Thereafter, the terpene solvent evaporates and diffuses to disappear from the joint, and two parts to be joined are joined.

  In the present invention, the terpene solvent (for example, d-limonene) has been used for joining (welding) between the two parts of the developing unit and the process cartridge because the terpene solvent is a styrene resin composition. Focusing on the melting mechanism, the frame body / part to be joined needs to be a styrene resin composition.

  The styrenic resin composition is not particularly limited as long as it is dissolved in a terpene solvent, but as a styrenic resin composition that can be suitably used as a material for a process cartridge, a rubber-modified styrenic material, HIPS (high-density resin) is used. Impact polystyrene). This material is a mixture of a rubber-like polymer or a rubber-like copolymer in order to improve impact resistance to PS (polystyrene) that is inexpensive and has good fluidity.

  In the present invention, it is preferable to use a mixture of a rubbery polymer or a rubbery copolymer having an average particle size of 0.5 to 3.0 μm as HIPS (high impact polystyrene). This is because when the average particle size of the rubber-like polymer or copolymer to be mixed is small, appearance defects (for example, scratches) at the time of molding tend to occur when molding the cartridge part, and conversely, the average particle size This is because if the diameter is large, the weldability of the toner seal member (not shown) tends to decrease. The rubbery polymer or rubbery copolymer is selected from the group consisting of polybutadiene, styrene-butadiene copolymer, polyisoprene, butadiene-isoprene copolymer, natural rubber, and ethylene-propylene copolymer. Is preferably used.

  As described above, since the terpene solvent dissolves the styrene material, not only the HIPS but also the styrene resin composition constituting the process cartridge includes parts using GPPS (general polystyrene not reinforced with rubber), ABS (acrylonitrile). A part using butadiene / styrene copolymer), a part using modified PPE (modified polyphenylene ether resin), or a styrene-based elastomer can be used.

  In this embodiment, d-limonene is used as the terpene solvent, and HIPS (a styrene polymer mixed with 8% by mass of polybutadiene rubber having an average particle diameter of 0.8 μm) is used as the developing frame body and the side cover. ) Was used. Further, as the developing roller bearing portion, a polyacetal resin that is not dissolved in a terpene solvent is used. This is because a material having high slidability is required to rotate and slide with the developing roller 5a.

  As described above, the injected terpene solvent dissolves the styrene material but does not dissolve the polyacetal resin. Therefore, when the terpene solvent reaches the portion 24 where the developing roller bearing member 13 and the positioning shaft of the side cover 11 are engaged, only the positioning shaft 11a of the side cover is dissolved, and the position between the positioning portion and the developing roller bearing member 13 is increased. Since the accuracy may decrease, it is preferable that the terpene solvent does not reach the engaging portion 24.

  Therefore, in the present embodiment, in order to prevent the terpene solvent from reaching the engaging portion 24, the entrance of the hole 8d of the developing device frame has an annular shape that is about 1 mm larger than the radius of the joining surface as shown in the figure. A step portion 25 having a depth of 1 mm was provided (FIGS. 1 and 2). By providing this stepped portion 25, a space much larger than the narrow gap of the joint surface 20 where the capillary phenomenon occurs can be formed into an annular shape. Therefore, the inflow of the terpene solvent using the capillary phenomenon occurs before this space, that is, the joint surface. Therefore, it is possible to prevent the terpene solvent from reaching the engaging portion 24 between the developing roller bearing portion and the side cover positioning shaft. In addition, since the accuracy of the injection amount of the terpene solvent injector 31 can be lowered by this, a relatively inexpensive injector can be selected, and production merit can be obtained.

  As described above, according to the present invention, the strength of the engaging portion (joining portion) can be improved and the position can be increased by joining the positioning shaft of the side cover made of styrene resin and the engaging portion of the developing device frame. Accuracy can be improved. In addition, by providing a stepped portion that becomes a wide space at the end of the joint, the capillary phenomenon can be stopped at that location, and parts made of non-styrenic materials such as the developing roller bearing are about to be joined. Even if the terpene solvent is injected in a state of being interposed between the styrene-based parts, the terpene-based solvent can be prevented from flowing into the parts made of a material that is not styrene-based.

FIG. 5 is a schematic cross-sectional view illustrating an engaging portion of a developing frame, a side cover, and a developing roller bearing member in the developing unit according to the embodiment of the present invention. FIG. 5 is a perspective view showing the vicinity of a positioning hole of a developing device frame according to an embodiment of the present invention. It is an expansion perspective view which shows the positioning shaft of the side cover and side cover of the Example of this invention. FIG. 4 is a schematic perspective view of the developing unit according to the embodiment of the present invention before assembly of a side cover and a developing roller driving gear. FIG. 2 is a schematic perspective view of a developing unit according to an embodiment of the present invention. It is a schematic cross-sectional view showing a process cartridge in an image forming apparatus of a conventional example and an embodiment of the present invention. It is a schematic cross section which shows the process cartridge of a prior art example and the Example of this invention. It is a model perspective view which shows the process cartridge of the prior art example and the Example of this invention. FIG. 6 is a schematic perspective view of a developing unit according to a conventional example and an embodiment of the present invention.

Explanation of symbols

L ... Laser S ... Recording paper Y ... Direction C ... Cleaning unit D ... Development unit Q ... Terpene solvent (d-limonene)
DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus 2 ... Scanner 3 ... Process cartridge 4 ... Charging means 4a ... Charging roller 5 ... Developing means 5a ... Developing roller 5b ... Developing blade 5c ... Drive gear 6 ... Cleaning means 7 ... Photosensitive drum 8 ... Developing frame 8a ... Toner storage portion 8b ... Toner conveying member 8d ... Hole 8d3 ... End surface 9 ... Cover member 10 ... Cleaning frame 10a ... Shaft member 11 ... Side cover 11a ... Positioning shaft 11a2 ... End surface 11b ... Arm portion 11c ... Side cover fixing Location 12 ... Side cover 12a ... Positioning shaft 13, 14 ... Developing roller bearing 15 ... Drive gear train 16 ... Pressure member 17 ... Spacer member 20 ... Surface 21 ... Hole 22 ... Slit 23 ... Tip 24 ... Engagement Part 25 ... Step part 31 ... Injection machine 40, 41, 42 ... Arrow 51 ... Transfer roller 52 ... Recording paper stacking plate 53 ... Paper feed roller 54 ... Minutes Pad 55 ... intermediate roller 56 ... conveying rollers 57 ... fuser 58 ... intermediate sheet discharge rollers 59 ... discharge roller

Claims (4)

Developing means having an image carrier;
A first developing frame formed of a styrenic resin composition containing the developing means;
Having one end side of the first developing frame and a plurality of second frames formed of a styrene resin composition sandwiching the side surface on the other end side;
The first developing frame and the second frame each have a plurality of positioning portions for positioning the second frame relative to the first developing frame,
The second frame supports a support member that supports the image carrier,
The support member is supported by the positioning portion of the second frame body, and the first frame body and the second frame are assembled when the first developing frame body and the second frame body are assembled. Sandwiched and assembled with the body,
At least one of the positioning portions has a joint surface that joins the first developing frame and the second frame,
At least one of the first developing frame and the second frame has an injection port for injecting a terpene solvent, and at least one of the first developing frame and the second frame Are provided with recesses, slits or chamfers for forming a flow path communicating with the inlet, and the terpene solvent is supplied to at least a part of the joint surface before welding and fixing through the flow path. Is composed of
The supply of the terpene solvent to the first flow path from the inlet to the vicinity of the joint surface, the second flow path from the first flow path to the joint surface, or both of the flow paths utilizes the capillary phenomenon. In the development unit,
The entrance of the positioning part on the first developing frame side, which is engaged with the positioning part of the second frame body, forms a space for blocking the supply of the terpene solvent due to capillary action. Development unit to do.   The developing unit according to claim 1, wherein the support member is made of a material different from that of the first developing frame and the second frame. In a process cartridge detachable from an electrophotographic image forming apparatus,
An electrophotographic photoreceptor, and developing means for developing the latent image formed on the electrophotographic photoreceptor using toner,
The developing means has an image carrier,
A first developing frame formed of a styrenic resin composition containing the developing means;
Having one end side of the first developing frame and a plurality of second frames formed of a styrene resin composition sandwiching the side surface on the other end side;
The first developing frame and the second frame each have a plurality of positioning portions for positioning the second frame relative to the first developing frame,
The second frame supports a support member that supports the image carrier,
The support member is supported by the positioning portion of the second frame body, and the first frame body and the second frame are assembled when the first developing frame body and the second frame body are assembled. Sandwiched and assembled with the body,
At least one of the positioning portions has a joint surface that joins the first developing frame and the second frame,
At least one of the first developing frame and the second frame has an injection port for injecting a terpene solvent, and at least one of the first developing frame and the second frame Are provided with recesses, slits or chamfers for forming a flow path communicating with the inlet, and the terpene solvent is supplied to at least a part of the joint surface before welding and fixing through the flow path. Is composed of
The supply of the terpene solvent to the first flow path from the inlet to the vicinity of the joint surface, the second flow path from the first flow path to the joint surface, or both of the flow paths utilizes a capillary phenomenon. ,
The entrance of the positioning part on the first developing frame side, which is engaged with the positioning part of the second frame body, forms a space for blocking the supply of the terpene solvent due to capillary action. To process cartridge.   The process cartridge according to claim 3, wherein the support member is made of a material different from that of the first developing frame and the second frame.

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