JP4470269B2 - Developing device, process device, and image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention belongs to the technical field of a developing device including a developer carrier, a process device including an electrostatic latent image carrier, and an image forming apparatus including at least one of these devices.
[0002]
[Prior art]
A laser printer as an image forming apparatus includes a developer carrier, that is, a developing roller, and an electrostatic latent image carrier, that is, a photosensitive drum. In this type of laser printer, a thin layer of toner as a developer is formed on the developing roller, and the developing roller is brought into contact with the photosensitive drum so that the toner selectively adheres to the photosensitive drum and is visible. Form an image.
[0003]
[Problems to be solved by the invention]
However, the toner adhering to the developing roller in a charged state deteriorates due to friction at the nip portion with the photosensitive drum. The deterioration of the toner results in a decrease in the charge amount, resulting in problems such as density change, fogging, and transfer failure in the image quality.
[0004]
Therefore, the present invention solves such problems, suppresses toner deterioration, avoids a decrease in charge amount, and can prevent problems such as density changes in image quality, fogging, and transfer defects. It is an object of the present invention to provide a developing device, a process device, and an image forming apparatus.
[0005]
[Means for Solving the Problems]
According to the first aspect of the present invention, the developer carrying member made of an elastic roller can be brought into contact with and separated from the electrostatic latent image carrying member, and the electrostatic latent image carrying member can be separated from the electrostatic latent image carrying member during development. In a developing device in which the developer carrier is opposed to the image carrier, A sheet-like spacer member for reducing the pressing force when the developer carrying member and the electrostatic latent image carrying member face each other in the image forming region; Between the developer carrier and the electrostatic latent image carrier There , Said In areas other than the image formation area Arranged It is characterized by that.
[0006]
According to the developing device of the first aspect, the sheet-like spacer member reduces the pressing force of the developer carrying member against the electrostatic latent image carrying member, thereby reducing the friction between them in the image forming area. The deterioration of the developer can be suppressed. Further, the impact when the developer carrying member comes into contact with the electrostatic latent image carrying member can be buffered by the spacer member.
According to a second aspect of the present invention, in the developing device according to the first aspect, the side seal member that slidably rubs against a part of the circumferential surface at both ends in the length direction of the developer carrier, and the electrostatic latent image. Drum wipers are further provided at both ends of the image carrier outside the image forming area and corresponding to the peripheral surfaces of both ends of the developer carrier, and the spacer member is an attachment region of the side seal member , And a drum wiper attachment region. In this way, the toner does not adhere to the spacer member, so that it is possible to always exhibit a stable function of the spacer member.
[0007]
According to a third aspect of the present invention, in the developing device according to the first or second aspect, the spacer member is made of a synthetic resin.
[0008]
According to the third aspect of the present invention, the developer carrier and the electrostatic latent image carrier can be prevented from being scraped by forming the spacer member from a synthetic resin.
[0009]
According to a fourth aspect of the present invention, in the developing device according to any one of the first to third aspects, the developer carrier is formed on a rubber base material and a surface of the base material. It is characterized by comprising a coat layer.
[0010]
According to the developing device of the fourth aspect, sufficient strength can be ensured by the coat layer, and as a result, scraping by the spacer member can be prevented. Further, even when rubber having high flexibility is used as the base material, the base material is not covered with the coating layer, so that the base material does not contaminate the electrostatic latent image carrier.
[0011]
According to a fifth aspect of the present invention, in the developing device according to the fourth aspect, the coat layer is formed of at least one selected from the group consisting of a urethane resin, a polyimide resin, and a fluororesin. .
[0012]
According to the developing device of the fifth aspect, it is possible to impart excellent strength to the coat layer, and therefore it is possible to reliably prevent the scraping by the spacer member.
[0013]
According to a sixth aspect of the present invention, in the developing device according to the fourth or fifth aspect, the base material of the developer carrying member has an Asker C hardness of 70 or less.
[0014]
According to the developing device of the sixth aspect, it is possible to ensure a stable contact state between the developer carrier and the electrostatic latent image carrier due to a predetermined pressing force.
[0015]
According to a seventh aspect of the present invention, in the developing device according to the first or third aspect, the developer carrying member is formed of urethane rubber.
[0016]
According to the developing device of the seventh aspect, since the urethane rubber has an excellent strength, it is possible to prevent the developer carrier from being scraped by the spacer member.
[0017]
[0018]
[0019]
[0020]
[0021]
According to the eighth aspect of the present invention, the developer carrying member formed of an elastic roller can be brought into contact with and separated from the electrostatic latent image carrying member, and the developer carrying is carried with respect to the electrostatic latent image carrying member during development. In the process device that makes the body contact each other, A sheet-like spacer member for reducing the pressing force when the developer carrying member and the electrostatic latent image carrying member face each other in the image forming region; Between the developer carrier and the electrostatic latent image carrier There , Said In areas other than the image formation area Arranged It is characterized by that.
[0022]
According to the process apparatus of the eighth aspect, the sheet-like spacer member reduces the pressing force of the developer carrying member against the electrostatic latent image carrying member, and thereby reduces the friction between both of them in the image forming area. The deterioration of the developer can be suppressed. Further, the impact when the developer carrying member comes into contact with the electrostatic latent image carrying member can be buffered by the spacer member.
According to a ninth aspect of the present invention, in the process apparatus according to the eighth aspect, the side seal member that slidably rubs against a part of the circumferential surface at both ends in the length direction of the developer carrier, and the electrostatic latent image. Drum wipers are further provided at both ends of the image carrier outside the image forming area and corresponding to the peripheral surfaces of both ends of the developer carrier, and the spacer member is an attachment region of the side seal member , And a drum wiper attachment region. In this way, the toner does not adhere to the spacer member, so that it is possible to always exhibit a stable function of the spacer member.
[0023]
According to a tenth aspect of the present invention, in the process apparatus according to the eighth or ninth aspect, the spacer member is made of a synthetic resin.
[0024]
According to the process apparatus of the tenth aspect, the developer member and the electrostatic latent image carrier can be prevented from being scraped by forming the spacer member from synthetic resin.
[0025]
[0026]
[0027]
[0028]
[0029]
An image forming apparatus according to an eleventh aspect of the present invention includes the developing device according to any one of the first to seventh aspects. According to a twelfth aspect of the present invention, an image forming apparatus of the present invention includes the process apparatus according to any one of the eighth to tenth aspects.
[0030]
According to the image forming apparatus according to any one of claims 11 and 12, the effect brought about by the developing device according to any one of claims 1 to 7, or any one of claims 8 to 10. An image forming apparatus having an effect brought about by the process apparatus described in the above is obtained.
[0031]
[0032]
[0033]
According to a thirteenth aspect of the present invention, in the image forming apparatus according to the twelfth aspect, a color image is formed by providing a plurality of the developer carriers.
[0034]
According to the image forming apparatus of the thirteenth aspect, during the switching operation of the plurality of developer carriers, the impact when the developer carrier contacts the electrostatic latent image carrier can be buffered by the spacer member.
[0035]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[0036]
(First embodiment)
First, a first embodiment of the present invention will be described with reference to FIGS. In the first embodiment, a printer as an image forming apparatus that is an object of the present invention includes a process cartridge 2, and the process cartridge 2 further includes a developing device that is an object of the present invention, that is, The developing unit 4 is included.
[0037]
(Schematic configuration of the printer)
FIG. 1 is a schematic sectional side view of a printer as an image forming apparatus. As shown in FIG. 1, a process cartridge 2 including a drum unit 3 and a developer unit 4 is detachably disposed at a substantially central portion in a main body housing 1 of the printer. FIG. 2 shows a cross section of the process cartridge 2.
[0038]
A photosensitive drum 13 as an electrostatic latent image carrier is rotatably disposed in the drum unit 3, and a transfer roller 14 is provided below the photosensitive drum 13 so as to rotate while being pressed against the photosensitive drum 13. A charger 36 as a charging unit for charging the photosensitive surface of the photosensitive drum 13 is attached above the photosensitive drum 13. Further, a light incident portion 31 is formed in the upper portion of the case 30 of the drum unit 3 at a position adjacent to the charger 36 along the axial direction of the photosensitive drum 13.
[0039]
The photosensitive drum 13 is made of a positively chargeable material, for example, an organic photoreceptor whose main component is a positively chargeable polycarbonate. Specifically, the photosensitive drum 13 is a light having a predetermined thickness (for example, about 20 μm) in which a photoconductive resin is dispersed in polycarbonate on the outer periphery of a cylindrical sleeve made of aluminum, for example. It is composed of a hollow drum having a conductive layer formed thereon, and is pivotally supported by the case 30 in a state where the cylindrical sleeve is grounded. Further, the photosensitive drum 13 is rotationally driven in the direction of the arrow by a driving unit (not shown).
[0040]
The charger 36 is composed of a scorotron charger for positive charging that generates corona discharge from a charging wire made of tungsten or the like, for example.
[0041]
In the developing unit 4 as a developing device, a developing roller 22 as a developer carrying means is rotatably arranged while facing the photosensitive drum 13, and toner as a developer stored in the developing unit 4 is received. The developing roller 22 conveys it to a position facing the photosensitive drum 13 to perform development.
[0042]
The developing roller 22 is provided with a cylindrical base material formed of conductive silicone rubber containing conductive carbon fine particles on a core metal formed of stainless steel or the like. A coat layer is formed on the top. This coat layer is formed from at least one selected from the group consisting of urethane resin, polyimide resin and fluororesin. Here, the base material preferably has an Asker C hardness of 70 or less. The reason for this will be described in detail later.
[0043]
Note that the developing roller 22 does not necessarily have to be made of conductive silicone rubber, and may be made of conductive urethane rubber. Thus, when a base material is comprised from urethane rubber, the coat layer mentioned above is not necessarily required.
[0044]
The toner is a positively chargeable non-magnetic one-component developer, which is formed into a spherical shape by a suspension polymerization method, a well-known colorant such as carbon black, nigrosine, triphenylmethane, quaternary It has toner base particles having a particle diameter of 6 μm to 10 μm and an average particle diameter of 8 μm obtained by adding a charge control agent such as an ammonium salt. The toner is constituted by adding silica as an external additive to the surface of the toner base particles.
[0045]
Such a polymerized toner has high fluidity and enables extremely high-definition development, but because of its high fluidity, toner leakage is likely to occur. Therefore, the developer unit 4 of the present embodiment is provided with a side seal member 60 for preventing such toner leakage.
[0046]
The side seal member 60 is formed of a square columnar sponge, and is bonded to a portion corresponding to both ends of the developing roller 22 in the casing 51 with a double-sided adhesive tape as shown in FIG. As this double-sided pressure-sensitive adhesive tape, for example, a tape in which a pressure-sensitive adhesive is applied to the front and back of a base material made of a nonwoven fabric with a uniform thickness is used. The side seal members are compressed and elastically deformed on the peripheral surfaces of both end portions of the developing roller 22 rotatably supported by the casing 51, whereby the surface of the side seal member 60 is formed at both end portions of the rotating developing roller 22. Leakage of the developer in the side direction is prevented while contacting the peripheral surface with an appropriate pressure. The side seal member 60 is preferably provided with a rubbing portion with the developing roller 22 made of Teflon felt or the like.
[0047]
A lower side seal 61 is used in combination with the side seal member 60. The lower side seal 61 is made of sponge, which is a rectangular parallelepiped foamed elastic body, and is bonded to the casing 51 with a double-sided adhesive tape so as to contact the side seal member 60 as shown in FIG. The lower side seal 61 is sandwiched between a lower film (not shown) that contacts the lower side of the developing roller 22 and the housing 51 and is pressed by the lower film that is bent by the pressure from the developing roller 22. As a result, the lower side seal 61, which is a foamed elastic body, is compressed and inserted between the lower film and the casing 51, and the lower film is closed by closing the gap between the lower film and the casing 51 so as not to generate a gap. And the toner leakage from the joint portion of the side seal member 60 is prevented.
[0048]
The region Z2 sealed by the side seal member 60 described above is shown in FIG. The side seal member attachment areas Z2 are formed on both sides of the developing roller 22, and an image forming area, that is, a toner adhesion area Z3 is formed between the side seal member attachment areas Z2 (FIGS. 3 and 3). 4). 3 and 4, Z4 indicates a region slightly smaller than the toner adhesion region Z3, which corresponds to the maximum printable paper size.
[0049]
A fixing device 5 including a heating roller 15 and a pressure roller 16 is disposed downstream of the process cartridge 2 in the conveyance direction of the paper P as described above. The fixing device 5 fixes the toner transferred onto the paper P onto the paper P by the heating action of the heating roller 15 and the pressurizing action of the heating roller 15 and the pressure roller 16.
[0050]
In addition, a synthetic resin cover discharge tray 1a made of synthetic resin for placing the paper discharged from the fixing device 5 is provided on the upper portion of the main body housing 1, and the lower surface of the discharge tray 1a is provided. A laser scanner unit 7 including a laser light emitting unit, a polygon mirror 18, a lens 19, a plurality of reflecting mirrors 20 and the like is attached via a frame.
[0051]
A paper feeding unit 6 is arranged below the process cartridge 2. The paper feed unit 6 includes a paper feed cassette 8 that can be mounted from the front (arrow A) direction at the bottom of the main body housing 1, a support plate 9 on which paper P as a transfer medium is stacked in the paper feed cassette 8, and a paper feed A paper feed roller 10 for taking out the paper P from the paper cassette 8 and a separation pad 11 for separating the paper P to be taken out one by one are provided.
[0052]
Further, in the printer according to the present embodiment, a pair of registration rollers 12 a and 12 b is provided on the downstream side of the paper feeding unit 6 in the transport direction of the paper P. The registration roller pairs 12 a and 12 b are roller pairs for transporting the paper P supplied from the paper feeding unit 6 to the pressure contact portion between the photosensitive drum 13 and the transfer roller 14 in a timely manner. The upper registration roller 12a is attached to the process cartridge 2 side, and the lower registration roller 12b is attached to the printer main body side.
[0053]
The printer of the present embodiment as described above, when print data is transmitted together with a print command from an external device (not shown) such as a personal computer, the paper P as a transfer medium stacked on the support plate 9 of the paper feed cassette 8. Are separated one by one by the separation pad 11 as the sheet feeding roller 10 of the sheet feeding unit 6 rotates, and then pressed against the photosensitive drum 13 and its lower surface side in the process cartridge 2 via the pair of registration rollers 12a and 12b. It is conveyed between the transfer roller 14 as a transfer means.
[0054]
On the other hand, the surface of the photosensitive drum 13 is uniformly charged by the charger 36, and the laser beam emitted from the emission hole on the lower surface of the frame supporting the laser scanner 7 is the case in the process cartridge 2, that is, the drum unit 3. An electrostatic latent image is formed by scanning the upper peripheral surface of the rotating photosensitive drum 13 which is irradiated from the upper light incident portion 31 of the case 30 which is the housing of the above. Further, as will be described later, a thin layer of toner is formed on the developing roller 22 in the developing unit 4, and the toner is transported to a portion facing the electrostatic latent image by the rotation of the developing roller 22, so that the electrostatic latent image The toner is visualized by the adhesion of the toner and then transferred to the paper P in the pressure transfer area of the transfer roller 14 and the photosensitive drum 13. The sheet P after the transfer is fed between the heating roller 15 and the pressure roller 16 in the fixing device 5 and is subjected to a heat fixing action, and the sheet P after the fixing is discharged from the sheet discharge path 17 to the cover-unit discharge tray. It is discharged on 1a.
[0055]
When the toner is consumed during the printing operation and the toner needs to be replenished, the process cartridge 2 in use is removed from the front surface of the printer body as shown in FIG. 6, and further as shown in FIG. Remove the old developer unit 4 from the process cartridge 2, install the new developer unit 4, and then insert the process cartridge 2 from the front of the printer body again and attach it to the printer body. The toner can be supplied without any trouble. If the photosensitive drum 13 is deteriorated, the process cartridge 2 is similarly taken out, the photosensitive cartridge 3 is replaced with a new one, and the process cartridge 2 is mounted on the printer body again.
[0056]
On the other hand, if the image forming operation is continued, a small amount of toner may leak as the developing roller 22 rotates and adhere to the photosensitive drum 13. In addition, a small amount of toner may leave the developing roller 22 and become mist and adhere to the photosensitive drum 13.
[0057]
Such toner leakage often occurs from both ends of the developing roller 22 in the longitudinal direction. In addition, the mist toner is often insufficiently charged or uncharged.
[0058]
The toner adhering to the photosensitive drum 13 in this manner is collected again by the developing roller 22 in the area corresponding to the image forming area Z3, but is not collected in the area corresponding to the outer side, and therefore gradually onto the photosensitive drum 13. Accumulate and stick.
[0059]
In such a state, the toner stuck between the developing roller 22 and the photosensitive drum 13 may be pinched, and the contact state between the developing roller 22 and the photosensitive drum may become unstable.
[0060]
Therefore, in this embodiment, a drum wiper as a developer removing member that removes the toner on both ends of the photosensitive drum 13 and a toner storage portion are provided, so that the above problem can be reliably prevented. Hereinafter, the configurations of the drum wiper and the toner storage unit in the present embodiment will be described in detail.
[0061]
FIG. 8 is a plan view of the drum unit 3 with the developing unit 4 removed. In FIG. 8, the photosensitive drum 13 is indicated by a two-dot chain line.
[0062]
In the present embodiment, as shown in FIG. 8, toner storage portions 40 and 41 as developer storage portions are provided at positions corresponding to both ends of the photosensitive drum 13. As shown in FIGS. 9A and 9B, these toner storage portions 40 and 41 are rectangular storage portions surrounded by walls on all sides, and are integrally formed with the drum unit 3.
[0063]
9A and 9B of the toner storage portions 40 and 41, drum wipers 42 and 43 as developer removing members are provided as shown in FIGS. 9C and 9D. Affixed with double-sided tape.
[0064]
The drum wipers 42 and 43 are formed of a PET film as an example. In addition, a resin film such as a urethane film can be used.
[0065]
When the drum wipers 42 and 43 are affixed to the toner storage portions 40 and 41, and then the photosensitive drum 13 is attached to the drum unit 3, the drum wipers 42 and 43 are attached to the photosensitive drum 13 as shown in FIG. And press contact with the peripheral surface of both ends. 10A is a cross-sectional view taken along line AA when the photosensitive drum 13 is mounted on the drum unit 3 shown in FIG.
[0066]
When the photosensitive drum 13 is mounted, the drum wiper 42 is brought into contact with the photosensitive drum 13 in the counter direction, as shown in FIG. 10B, which is an enlarged view of the circled portion C in FIG. Let If the contact is made in the forward direction as indicated by the two-dot chain line, good toner removal cannot be performed. Na Because.
[0067]
With the above-described configuration, the drum wipers 42 and 43 are provided at both ends outside the image forming area of the photosensitive drum 13 and at positions corresponding to both ends of the developing roller 22. This position is set because toner leakage from the developing unit 4 is likely to occur from both ends of the developing roller 22 in the developing unit 4, and the toner transferred to both ends of the photosensitive drum 13 is This is because it cannot be collected by the developing roller 22 or the like.
[0068]
As described above, according to the present embodiment, the toner on the photosensitive drum 13 can be reliably removed by the drum wipers 42 and 43 even when toner leakage or mist from the developing unit 4 occurs. Further, it is possible to prevent the toner fixed on the photosensitive drum 13 from being sandwiched between the developing roller 22 and the photosensitive drum 13, and the contact state between the developing roller 22 and the photosensitive drum 13 to be unstable.
[0069]
A printer as an image forming apparatus has the above-described schematic configuration, but is provided with a spacer member 23 for preventing toner deterioration due to friction between the developing roller 22 and the photosensitive drum 13.
[0070]
Hereinafter, the structure of the spacer member in this embodiment is demonstrated in detail, referring FIG.2 and FIG.4.
[0071]
(Detailed configuration of spacer member)
The spacer member 23 is formed in a sheet shape from a synthetic resin, for example, PET (polyethylene terephthalate). The spacer member 23 is disposed between the developing roller 22 and the photosensitive drum 13 in an area other than the image forming area, that is, the toner adhesion area Z3. That is, the spacer member 23 is disposed between the developing roller 22 and the photosensitive drum 13 on both side portions of the developing roller 22 other than the toner adhesion region Z3.
[0072]
As shown in FIG. 2, the upper end of each spacer member 23 is attached to the front upper end of the housing of the developing unit 4, while the lower end is attached to the front lower end of the housing. The attachment method of the spacer member 23 is arbitrary, but a double-sided adhesive tape is used in consideration of ease of attachment. Both ends of the spacer member 23 are attached to each other, but at least an end portion (upper end in the present embodiment) located on the upstream side in the rotation direction of the developing roller 22 may be fixed to the developing device unit 4 side. .
[0073]
A region Z1 to which the spacer member 23 is attached is shown in FIG. As is apparent from the above, the spacer member attachment region Z1 is located outside the toner adhesion region Z3 in the axial direction of the developing roller 22, and is disposed outside the inner end of the side seal member 60 described above. . In this embodiment, the side seal member attachment region Z2 completely includes the spacer member attachment region Z1, and the latter inner boundary line is more in the axial direction of the developing roller 22 than the former inner boundary line. Located on the outside.
[0074]
Further, the spacer member attachment area Z1 to which the spacer member 23 is attached is disposed outside the inner ends of the drum wipers 42 and 43 provided outside the image forming area in the axial direction of the photosensitive drum 13. Although not shown, the attachment region of the drum wipers 42 and 43 completely includes the spacer member attachment region Z1, and the latter inner boundary line is more in the axial direction of the photosensitive drum 13 than the former inner boundary line. In FIG.
[0075]
The spacer member 23 described above is disposed between the developing roller 22 and the photosensitive drum 13 in the spacer member attachment region Z1, but in the toner adhesion region Z3, a predetermined pressing between the developing roller 22 and the photosensitive drum 13 is performed. Impression development is made possible by allowing contact by pressure. That is, in the toner adhesion region Z3, the pressing force of the developing roller 22 against the photosensitive drum 13 is appropriately reduced to enable impression development, and at the same time, the toner is deteriorated due to the friction between the developing roller 22 and the photosensitive drum 13. Suppress. Further, since the spacer member 23 is mounted so as to be included in the side seal member mounting region Z2 and the mounting region of the drum wipers 42 and 43, the toner does not adhere to the spacer member 23, and therefore, always. The stable function of the spacer member 23 can be exhibited.
[0076]
When the developing roller 22 having an Asker C hardness of 65 is used, the spacer roller 23 having a thickness of 0.3 mm can be used to develop the developing roller for the photosensitive drum 13 without causing printing defects. The pressing force of 22 could be reduced appropriately. On the other hand, when the developing roller 22 having an Asker C hardness of greater than 70 is used, even if the thickness of the spacer member 23 is adjusted, the developing roller 22 is within a range in which the pressing force of the developing roller 22 against the photosensitive drum 13 is effective. The developing roller 22 could not stably come into contact with the photosensitive drum 13, and a part of the printing was lost. From this, in this embodiment, it was obtained that it is preferable to use a developing roller 22 having an Asker C hardness of 70 or less.
[0077]
(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. In the second embodiment, a printer as an image forming apparatus that is an object of the present invention includes a process cartridge 2, and the process cartridge 2 further includes a process apparatus that is an object of the present invention. It is out. Here, the process device refers to a portion excluding the developing device, that is, the developing unit 4 from the process cartridge 2, that is, the drum unit 3. In addition, the same code | symbol is attached | subjected to a common location with 1st Embodiment, and description is abbreviate | omitted.
[0078]
As shown in FIG. 11, the second embodiment differs from the first embodiment in that the spacer member 23 is attached to the case 30 of the drum unit 3. That is, the spacer member 23 is attached to the portion of the case 30 located above the photosensitive drum 13 only at the upper end thereof.
[0079]
Also in the second embodiment, the same side seal member and drum wiper as in the first embodiment are provided, and the positional relationship among the spacer member 23, the side seal member, and the drum wiper is the first. This is the same as the embodiment.
[0080]
In the second embodiment, the same effect as in the first embodiment can be obtained.
[0081]
(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIGS. In the third embodiment, a color printer as an image forming apparatus that is an object of the present invention includes four developing devices 4Y and 4M corresponding to yellow, magenta, cyan, and black colors that are objects of the present invention. 4C, 4Bk.
[0082]
In the third embodiment, the electrostatic latent image carrier 13 is configured as an endless belt, while the four developing devices 4Y, 4M, 4C, and 4Bk can be slid toward the electrostatic latent image carrier 13 respectively. Thus, these are arranged in parallel, and these are selectively contacted with the electrostatic latent image carrier 13.
[0083]
A developing roller 22 is provided in a front portion of each case of the developing devices 4Y, 4M, 4C, and 4Bk, and a spacer member 23 is provided so as to contact the developing roller 22. The upper end of the spacer member 23 is attached to the upper part on the front side of the case, while the lower end is attached to the lower part on the front side of the case. Therefore, when any one of the developing devices 4Y, 4M, 4C, and 4Bk slides in the horizontal direction toward the electrostatic latent image carrier 13, the spacer member 23 provided in the slid developing device 4 has the developing device 4 Between the developing roller 22 and the electrostatic latent image carrier 13.
[0084]
In configurations other than those described above, the printer according to the third embodiment has the same basic configuration as the printer according to the first embodiment, and thus description thereof is omitted.
[0085]
In each of the developing devices 4Y, 4M, 4C, and 4Bk of the third embodiment, side seal members similar to those of the developing device in the first embodiment are provided, while the electrostatic latent image carrier 13 includes A wiper similar to the drum wiper in the first embodiment is provided. The positional relationship among the spacer member 23, the side seal member, and the wiper is the same as that in the first embodiment.
[0086]
In the third embodiment, the same effect as in the first embodiment can be obtained.
[0087]
In the third embodiment, it is necessary to quickly perform the switching operation of the developing devices 4Y, 4M, 4C, and 4Bk that are brought into contact with the electrostatic latent image carrier 13 during the image forming operation. The abrupt contact with the electrostatic latent image carrier 13 may cause problems such as rotation of the developing roller 22 and unstable conveyance of the electrostatic latent image carrier 13 due to the impact. However, according to the present invention, the impact is mitigated by the spacer member 23, so that such a problem can be reduced. In particular, when an endless belt is used for the electrostatic latent image carrier 13 as in the third embodiment, the effect of stabilizing the conveyance of the electrostatic latent image carrier 13 is great. As in the third embodiment, the effect is particularly remarkable when the transport direction of the electrostatic latent image carrier 13 and the moving direction of the developing roller 22 are opposite in the nip portion.
[0088]
As described above, the present invention has been described based on the embodiments, but the present invention is not limited to the above-described embodiments, and various improvements and modifications can be easily made without departing from the spirit of the present invention. It can be guessed.
[0089]
【The invention's effect】
According to the developing device of the first aspect, since the sheet-like spacer member is disposed in a portion other than the image forming area between the developer carrier and the electrostatic latent image carrier, the spacer member It is possible to reduce the pressing force of the developer carrying member against the electrostatic latent image carrying member, thereby alleviating the friction between them in the image forming region and suppressing the deterioration of the developer. Further, the impact when the developer carrying member comes into contact with the electrostatic latent image carrying member can be buffered by the spacer member. Further, according to the developing device of the second aspect, the toner does not adhere to the spacer member, so that it is possible to always exhibit a stable function of the spacer member.
[0090]
According to the developing device of the third aspect, since the spacer member is made of synthetic resin, the developer carrier and the electrostatic latent image carrier can be prevented from being scraped.
[0091]
According to the developing device of claim 4, since the developer carrying member is composed of the rubber base material and the coating layer formed on the surface of the base material, the coating layer has sufficient strength. As a result, the scraping by the spacer member can be prevented. Further, even when rubber having high flexibility is used as the base material, the base material is not covered with the coating layer, so that the base material does not contaminate the electrostatic latent image carrier.
[0092]
According to the developing device of claim 5, since the coat layer is formed from at least one selected from the group consisting of urethane resin, polyimide resin and fluororesin, it imparts excellent strength to the coat layer. Therefore, it is possible to reliably prevent scraping by the spacer member.
[0093]
According to the developing device of the sixth aspect, since the base material of the developer carrier has an Asker C hardness of 70 or less, a predetermined amount of the developer carrier and the electrostatic latent image carrier is determined. A stable contact state by pressing force can be secured.
[0094]
According to the developing device of the seventh aspect, since the developer carrying member is formed of urethane rubber, it is possible to impart excellent strength to the developer carrying member and to suppress the developer carrying member from being scraped by the spacer member. .
[0095]
[0096]
[0097]
According to the process apparatus of the eighth aspect, since the sheet-like spacer member is disposed in a portion other than the image forming region between the electrostatic latent image carrier and the developer carrier, the spacer member It is possible to reduce the pressing force of the developer carrying member against the electrostatic latent image carrying member, thereby alleviating the friction between them in the image forming region and suppressing the deterioration of the developer. Further, the impact when the developer carrying member comes into contact with the electrostatic latent image carrying member can be buffered by the spacer member. Further, according to the process apparatus of the ninth aspect, the toner does not adhere to the spacer member, so that the function of the spacer member which is always stable can be exhibited.
[0098]
According to the process apparatus of the tenth aspect, since the spacer member is made of synthetic resin, it is possible to prevent the developer carrier and the electrostatic latent image carrier from being scraped.
[0099]
[0100]
[0101]
According to the present invention described in claims 11 and 12, the effect brought about by the developing device according to any one of claims 1 to 7, or any one of claims 8 to 10. An image forming apparatus having an effect brought about by the process apparatus described in 1) is obtained.
[0102]
[0103]
The image forming apparatus according to claim 13 is configured to form a color image by providing a plurality of the developer carriers, and at the time of the switching operation of the developer carriers in the plurality of developing devices, development is performed. The spacer member can cushion the impact when the agent carrier contacts the electrostatic latent image carrier.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating a schematic configuration of an image forming apparatus according to a first embodiment of the present invention.
2 is a cross-sectional view showing a schematic configuration of a process cartridge in the image forming apparatus of FIG. 1;
3 is a plan view showing a mounting position of a spacer member in the process cartridge of FIG. 2; FIG.
FIG. 4 is a partially enlarged view of FIG. 3;
FIG. 5 is a perspective view showing an attached state of the side seal member.
6 is a view for explaining a method of attaching and detaching a process cartridge to and from the image forming apparatus of FIG.
7 is a view for explaining a method for attaching and detaching the developing unit to the process cartridge of FIG. 2; FIG.
FIG. 8 is a plan view showing the drum unit with the developing unit and the photosensitive drum removed.
9A is a perspective view showing a left toner accommodating portion provided in the drum unit of FIG. 8, FIG. 9B is a perspective view showing a right toner accommodating portion provided in the drum unit of FIG. (A) is a perspective view showing a state where a drum wiper is attached to the toner accommodating portion of (A), and (D) is a perspective view showing a state where the drum wiper is attached to the toner accommodating portion of (B).
10A is a cross-sectional view taken along line AA in FIG. 8, and FIG. 10B is an enlarged view of a circled portion C in FIG.
FIG. 11 is a cross-sectional view showing a schematic configuration of a process cartridge according to a second embodiment of the present invention.
FIG. 12 is a cross-sectional view illustrating a schematic configuration of an image forming apparatus according to a third embodiment of the present invention.
13 is a partially enlarged view of the developing device of FIG.
[Explanation of symbols]
1 Body housing
2 Process cartridge
3 drum units
4 Developer unit
13 Photosensitive drum
14 Transfer roller
22 Development roller
23 Spacer member
30 cases
40, 41 Toner container
42,43 Drum wiper
60 Side seal member

Claims (13)

In a developing device in which a developer carrying member made of an elastic roller can be brought into contact with and separated from an electrostatic latent image carrying member, and the developer carrying member is brought into contact with and opposed to the electrostatic latent image carrying member during development. A sheet-like spacer member for reducing the pressing force when the developer carrying member and the electrostatic latent image carrying member face each other in the image forming region is provided with the developer carrying member and the electrostatic carrying member. It is between the latent image bearing member, a developing device, characterized in that arranged in a portion other than the image forming area. A side seal member that slidably rubs a part of the circumferential surface at both ends in the longitudinal direction of the developer carrier, and both ends outside the image forming area of the electrostatic latent image carrier, the developer carrier It further comprises a drum wiper provided at a position corresponding to the circumferential surface of both ends,
The developing device according to claim 1, wherein the spacer member is provided so as to be included in an attachment region of the side seal member and an attachment region of the drum wiper.   The developing device according to claim 1, wherein the spacer member is made of a synthetic resin.   4. The developer carrier according to claim 1, wherein the developer carrier includes a rubber base material and a coat layer formed on the surface of the base material. 5. Development device.   The developing device according to claim 4, wherein the coating layer is formed of at least one selected from the group consisting of a urethane resin, a polyimide resin, and a fluororesin.   6. The developing device according to claim 4, wherein the base material of the developer carrying member has an Asker C hardness of 70 or less.   The developing device according to claim 1, wherein the developer carrying member is made of urethane rubber. In a process apparatus in which a developer carrying member made of an elastic roller can be brought into contact with and separated from an electrostatic latent image carrying member, and the developer carrying member is opposed to the electrostatic latent image carrying member during development. A sheet-like spacer member for reducing the pressing force when the developer carrying member and the electrostatic latent image carrying member face each other in the image forming region is provided with the developer carrying member and the electrostatic carrying member. It is between the latent image bearing member, process equipment, characterized in that arranged in a portion other than the image forming area. A side seal member that slidably rubs a part of the circumferential surface at both ends in the longitudinal direction of the developer carrier, and both ends outside the image forming area of the electrostatic latent image carrier, the developer carrier It further comprises a drum wiper provided at a position corresponding to the circumferential surface of both ends,
The process apparatus according to claim 8, wherein the spacer member is provided so as to be included in an attachment region of the side seal member and an attachment region of the drum wiper.   The process apparatus according to claim 8, wherein the spacer member is made of a synthetic resin.   An image forming apparatus comprising the developing device according to claim 1.   An image forming apparatus comprising the process device according to claim 8.   The image forming apparatus according to claim 12, wherein a color image is formed by providing a plurality of the developer carriers.

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