JP3774657B2 - Charging device, process cartridge, and image forming apparatus using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a charging device, a process cartridge, and an image forming apparatus using the same.
[0002]
  More specifically,The surface movesA plate-like brush member disposed opposite to the member to be charged and having a tip portion in contact with the surface of the member to be chargedAnd an inclined member for inclining the brush member in the charged object moving direction upstream in the charged object moving direction in the width direction of the brush member;The present invention relates to a process cartridge using the charging device (including static elimination), and an image forming apparatus such as a copying machine or a printer using an electrophotographic method or an electrostatic recording method.
[0003]
An electrophotographic image forming apparatus forms an image on a recording medium using an electrophotographic image forming process. For example, an electrophotographic copying machine, an electrophotographic printer (such as an LED printer or a laser beam printer), an electrophotographic facsimile apparatus, and an electrophotographic word processor are included.
[0004]
The process cartridge is a cartridge in which at least one of a charging unit, a developing unit, and a cleaning unit and an electrophotographic photosensitive member as an image carrier are integrally formed, and the cartridge can be attached to and detached from the image forming apparatus main body. is there.
[0005]
The charging device has means for uniformly charging the electrophotographic photosensitive member to a predetermined polarity and potential.
[0006]
[Prior art]
Conventionally, a process cartridge system has been adopted in which an electrophotographic photosensitive member (hereinafter referred to as a photosensitive drum), a charging unit, a developing unit, a cleaning unit, and the like are integrated into a cartridge and the cartridge can be attached to and detached from the image forming apparatus main body. ing.
[0007]
The operability is further improved by this cartridge system, and the user can easily perform maintenance of the process means. Therefore, this cartridge system is widely used in the image forming apparatus main body.
[0008]
In addition, a cartridge configuration is realized in which the process means is divided into those having a long life and those having a short life, each process means is made into a cartridge, and can be used according to the life of the main process means. For example, a developing cartridge in which a toner container and a developing unit are integrally configured, or a drum cartridge in which a photosensitive drum, a charging unit, and a cleaning unit are integrally configured are employed.
[0009]
In recent years, a developer image corresponding to image information is formed by applying an image forming process including a step of uniformly charging a photosensitive drum to a predetermined polarity and potential, and the developer image is used as a transfer material. A cleaner that eliminates the cleaning device by transferring and outputting the image formed product, and removing and collecting the developer remaining on the photosensitive drum after the transfer process from the photosensitive drum by the simultaneous development cleaning in the developing means and reusing it. We propose an image-less system and provide a miniaturized image forming apparatus main body.
[0010]
For example, the charging polarity of the transfer residual developer (hereinafter referred to as transfer residual toner) remaining on the photosensitive drum after the transfer process is set to a regular value on the downstream side of the transfer unit and the upstream side of the charging unit in the rotation direction of the photosensitive drum. Providing developer charge amount control means (hereinafter referred to as toner charge amount control means) that matches the charging polarity to prevent the transfer charge toner from adhering to the contact charging member and preventing the occurrence of fogging images due to defective charging or the like. A cleanerless image forming apparatus and a process cartridge have been proposed (Japanese Patent Laid-Open No. 8-137368).
[0011]
[Problems to be solved by the invention]
The toner charge amount control means uses a brush-shaped member having moderate conductivity and is arranged so as to be directed toward the center of the photosensitive drum. When the photosensitive drum rotates, the tip of the brush part falls along the rotation direction. However, if the tip part falls in the opposite direction to the rotation direction during assembly or the like, and comes into contact with the rotation of the photosensitive drum in a counter state. The transfer residual toner on the photosensitive drum may be scraped off. In addition, if the brush part falls from the root of the raised part, the density and contact pressure of the hair in contact with the contact part with the photosensitive drum will be lowered, and the transfer residual toner will not be sufficiently charged. Since the remaining toner cannot be charged sufficiently, the contact charging member is contaminated with toner.
[0012]
Along with the diversification of user needs in recent years, a large amount of residual toner can be transferred at one time by continuous printing operation of images with high printing ratios such as photographic images and multiple development methods on photosensitive drums with colorization. The occurrence further promotes the above problems.
[0013]
Accordingly, the present invention relates to a charging device, a process cartridge, and an electrophotographic image forming apparatus that are provided with a brush-shaped member such as a developer charge amount control unit in a cleaner-less system. The counter contact with the rotation direction of the photosensitive member prevents the residual developer on the electrophotographic photosensitive member from being scraped off by the brush member, and the contact state (contact pressure) of the brush member with respect to the rotation direction of the electrophotographic photosensitive member. , The contact density) is stably maintained, and charge is imparted to the transfer residual toner satisfactorily, so that there is no defective charging or defective image, and the advantages of the cleanerless system can be fully utilized. An object of the present invention is to provide a process cartridge and an image forming apparatus.
[0014]
  The present invention is characterized by the following configuration.
  That is,A plate-like brush member disposed so as to face the charged body whose surface moves, and a tip portion of which is in contact with the surface of the charged body, and the brush member on the upstream side of the charged body moving direction in the width direction of the brush member In the charging member moving direction, the inclined member includes a rib-shaped member continuously long in the longitudinal direction of the brush member, and one end side of the rib-shaped member. The front end of the free end is pressed against the upstream side in the width direction of the brush member in the width direction of the brush member to incline the brush member in the direction of rotation of the charged body, and continuously in the longitudinal direction of the brush member. A long flexible sheet memberThe rib-shaped member tilts the brush member by pressing the brush member inside the brushed region of the brush member when viewed from the front end direction of the brush portion of the brush member, and the flexible sheet The member is inclined by pressing the tip side of the brush member with respect to the contact portion between the rib-shaped member and the brush member.A charging device characterized by that.
  Further, a process cartridge having the charging device and an image forming apparatus are provided.
[0083]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a color electrophotographic image forming apparatus as an embodiment will be described with reference to the drawings. In the following description, the longitudinal direction is a direction orthogonal to the conveyance direction of the recording medium 52 and refers to the same direction as the axial direction of the electrophotographic photosensitive member (hereinafter, photosensitive drum) 2. Further, left and right are left and right as viewed from the conveyance direction of the recording medium 52. Further, upper and lower are upper and lower in the mounted state of the cartridge.
[0084]
[Overall Description of Image Forming Apparatus]
First, the overall configuration of the color electrophotographic image forming apparatus will be schematically described with reference to FIG. FIG. 1 is an explanatory diagram of the overall configuration of a color laser beam printer which is an embodiment of a color toner image forming apparatus.
[0085]
The image forming unit of this color laser beam printer includes four process cartridges 1Y, 1M, 1C, and 1K (yellow color, magenta color, cyan color, and black color) each including a photosensitive drum 2 that is an image carrier. Above the cartridges 1Y, 1M, 1C, and 1K, exposure means 51Y, 51M, 51C, and 51K (laser beam optical scanning systems) corresponding to the respective colors are arranged in parallel.
[0086]
Below the image forming portion, a feeding means for feeding the recording medium 52, an intermediate transfer belt 54a for transferring a toner image formed on the photosensitive drum 2, and a toner image on the intermediate transfer belt 54a are recorded on the recording medium 52. A secondary transfer roller 54d for transferring to is disposed.
[0087]
Further, fixing means for fixing the recording medium 52 to which the toner image has been transferred, and discharging means for discharging and stacking the recording medium 52 outside the apparatus are arranged.
[0088]
Here, the recording medium 52 is, for example, paper, an OHP sheet, or cloth.
[0089]
The image forming apparatus of this example is an apparatus of a cleaner-less system. The transfer residual toner remaining on the photosensitive drum 2 is taken in the developing means, and a dedicated cleaner for collecting and storing the transfer residual toner is disposed in the process cartridge. Not done.
[0090]
Next, the configuration of each part of the image forming apparatus will be sequentially described in detail.
[0091]
[Paper Feeder]
The paper feeding unit feeds the recording medium 52 to the image forming unit, and includes a feeding cassette 53a in which a plurality of recording media 52 are stacked and stored, a feeding roller 53b, a double feed preventing retard roller 53c, It is mainly composed of a feeding guide 53d and a registration roller 53g.
[0092]
The feeding roller 53b is driven and rotated according to the image forming operation, and separates and feeds the recording medium 52 in the feeding cassette 53a one by one. The recording medium 52 is guided by the feeding guide 53d and is conveyed to the registration roller 53g via the conveyance rollers 53e and 53f.
[0093]
Immediately after the recording medium 52 is conveyed, the registration roller 53g stops rotating, and the recording medium 52 is corrected to be skewed by hitting the nip portion.
[0094]
During the image forming operation, the registration roller 53g performs a non-rotating operation for causing the recording medium 52 to stand still and a rotating operation for conveying the recording medium 52 toward the intermediate transfer belt 54a in a predetermined sequence. The toner image and the recording medium 52 in a certain transfer process are aligned.
[0095]
[Process cartridge]
The process cartridges 1Y, 1M, 1C, and 1K are integrally configured by arranging a charging unit and a developing unit around the photosensitive drum 2 that is an image carrier. The process cartridge can be easily removed from the apparatus main body by the user and replaced when the photosensitive drum 2 reaches the end of its life.
[0096]
In this example, for example, the number of rotations of the photosensitive drum 2 is counted, and when the predetermined count is exceeded, it is notified that the process cartridge has reached the end of its life.
[0097]
The photosensitive drum 2 of this example is a negatively charged organic photosensitive member, and has a commonly used photosensitive layer on an aluminum drum base having a diameter of about 30 mm, and a charge injection layer is provided as the outermost layer. Then, it is rotationally driven at a predetermined process speed, in this example, about 117 mm / sec.
[0098]
The charge injection layer is made of, for example, SnO as conductive fine particles in an insulating resin binder.₂A coating layer made of a material in which ultrafine particles are dispersed is used.
[0099]
As shown in FIG. 4, a drum flange 2b is fixed to the back end of the photosensitive drum 2, and a non-drive flange 2d is fixed to the front end. The drum shaft 2a passes through the center of the drum flange 2b and the non-drive flange 2d, and the drum shaft 2a, the drum flange 2b, and the non-drive flange 2d are rotated together. That is, the photosensitive drum 2 is rotated around the axis of the drum shaft 2a.
[0100]
The front end of the drum shaft 2a is rotatably supported by the bearing 2e, and the bearing 2e is fixed to the bearing case 2c. The bearing case 2c is fixed to the frame of the process cartridge.
[0101]
[Charging means]
The charging means 3 uses a contact charging method. In this example, the charging roller 3a is used as the charging member.
[0102]
As shown in FIG. 2, the charging roller 3a holds both ends of the cored bar 3b rotatably by bearing members (not shown), and is urged toward the photosensitive drum by a pressing spring 3d to thereby surface the photosensitive drum 2. Are pressed against each other with a predetermined pressing force, and are rotated by the rotation of the photosensitive drum 2.
[0103]
Reference numeral 3c denotes a charging roller cleaning member, which is a flexible cleaning film in this example. This cleaning film 3e is arranged in parallel with the longitudinal direction of the charging roller 3a and is fixed at one end to a support member 3f that reciprocates a certain amount in the longitudinal direction. It is arranged to form a contact nip. The supporting member 3f is reciprocated by a predetermined amount in the longitudinal direction by a driving means (not shown), and the surface of the charging roller is rubbed with the cleaning film 3e. As a result, deposits on the surface of the charging roller (fine powder toner, external additives, etc.) are removed.
[0104]
[Cleanerless system]
The outline of the cleanerless system in the image forming apparatus of this example will be described with reference to FIG. 2. The transfer residual toner on the photosensitive drum 2 after transfer is transferred to the charging unit a and the exposure unit b as the photosensitive drum continues to rotate. It is passed through and carried to the developing section c, and is simultaneously cleaned (collected) by the developing device 4.
[0105]
Since the untransferred toner on the surface of the photosensitive drum 2 passes through the exposure portion b, the exposure process is performed from the untransferred toner.
[0106]
However, the transfer residual toner includes normal polarity, reverse polarity (reversal toner), and low charge amount, and when the reverse toner or the low charge amount toner passes through the charging portion a. As a result of adhering to the charging roller 3a, the charging roller 3a contaminates the toner more than allowable, resulting in poor charging.
[0107]
In addition, in order to effectively perform the simultaneous cleaning of the transfer residual toner on the surface of the photosensitive drum 2 by the developing device 4, the charging polarity of the transfer residual toner on the photosensitive drum 2 carried to the developing unit c is negative. In addition, the charge amount needs to be a charge amount that can develop the electrostatic latent image on the photosensitive drum 2 by the developing device 4. Inverted toner and toner with an inappropriate charge amount cannot be removed and collected from the photosensitive drum 2 to the developing device 4, which causes a defective image.
[0108]
In addition, with the diversification of user needs in recent years, a large amount of untransferred toner is generated at a time due to continuous printing operations such as images with a high printing rate such as photographic images, which further promote the above-described problems. It is.
[0109]
Therefore, in this example, a transfer residual toner (residual developer image) equalizing means 3g for uniformizing the transfer residual toner on the photosensitive drum 2 is provided at a position downstream of the transfer portion d in the rotation direction of the photosensitive drum. In order to align the charging polarity of the residual toner to the negative polarity which is the normal polarity at the position downstream of the transfer drum in the photosensitive drum rotation direction from the transfer residual toner uniformizing means 3g and at the upstream side of the charging portion a in the photosensitive drum rotation direction. A toner (developer) charge control means 3h is provided.
[0110]
By providing the transfer residual toner uniformizing means 3g, even if the amount of pattern transfer residual toner on the photosensitive drum carried from the transfer portion d to the toner charge control means 3h is large, the toner remains on the photosensitive drum surface. Since the toner is distributed and non-patterned, the toner does not concentrate on a part of the toner charge control unit 3h, and the entire normal polarity charging process of the transfer residual toner by the toner charge control unit 3h is always performed. This is sufficiently done to effectively prevent the transfer residual toner from adhering to the charging roller 3a. Further, the occurrence of a ghost image of the transfer residual toner image pattern is also prevented.
[0111]
In this example, the transfer residual toner equalizing means 3g and the toner charge control means 3h are brush-like members having appropriate conductivity, and are arranged such that the brush portions are in contact with the photosensitive drum surface.
[0112]
These means are moved (reciprocated) in the longitudinal direction of the photosensitive drum by a driving source (not shown). By doing so, the transfer residual toner uniformizing means 3g and the toner charge control means 3h do not continue to be located at the same place on the photosensitive drum. For example, the overcharge portion and the charge due to uneven resistance of the toner charge control means 3h Even if there is an insufficient portion, it does not always occur on the same photosensitive drum surface portion. Therefore, fusion occurs on the photosensitive drum due to the overcharge of the minimal transfer residual toner, and the charging roller 3a is caused by insufficient charging. The transfer residual toner is prevented or alleviated.
[0113]
[Exposure means]
In this example, the exposure means 51Y, 51M, 51C, 51K to the photosensitive drum 2 is performed using a laser exposure means. That is, when an image signal is sent from the apparatus main body, the laser beam L modulated in accordance with this signal is scanned and exposed on the uniformly charged surface of the photosensitive drum 2. An electrostatic latent image corresponding to the image information is selectively formed on the surface of the photosensitive drum 2.
[0114]
The laser exposure means includes a solid laser element (not shown), a polygon mirror 51a, an imaging lens 51b, a reflection mirror 51c, and the like. Based on the input image signal, the solid-state laser element is controlled to emit light ON / OFF at a predetermined timing by a light emission signal generator (not shown). Laser light L emitted from the solid-state laser element is converted into a substantially parallel light beam by a collimator lens system (not shown) and scanned by a polygon mirror 51a that rotates at high speed. Then, an image is formed in a spot shape on the photosensitive drum 2 via the imaging lens 51b and the reflection mirror 51c.
[0115]
Thus, on the surface of the photosensitive drum 2, exposure in the main scanning direction by laser beam scanning and exposure in the sub-scanning direction by rotating the photosensitive drum 2 are performed, and an exposure distribution according to the image signal is obtained. That is, a bright portion potential with a lowered surface potential and a dark portion potential with no surface potential are formed by irradiation and non-irradiation of the laser beam L. An electrostatic latent image corresponding to the image information is formed by the contrast between the bright part potential and the dark part potential.
[0116]
[Development means]
The developing device 4 that is a developing means is a two-component contact developing device (two-component magnetic brush developing device), and as shown in FIG. 2, a carrier is placed on a developing sleeve 4a that is a developer carrying member including a magnet roller 4b. And a developer composed of toner. The developing sleeve 4a is provided with a regulating blade 4c having a predetermined gap, and a thin layer of developer is formed on the developing sleeve 4a as the developing sleeve 4a rotates in the arrow direction.
[0117]
As shown in FIG. 4, the developing sleeve 4a is disposed so as to have a predetermined gap with the photosensitive drum 2 by rotatably engaging the spacer 4k with the journal portions 4a1 having reduced diameters on both sides thereof. Is set so that the developer formed on the developing sleeve 4a can be developed in contact with the photosensitive drum 2. The developing sleeve 4a is driven to rotate at a predetermined peripheral speed in a clockwise direction indicated by an arrow which is a counter direction with respect to the rotation direction of the photosensitive drum 2 in the developing unit.
[0118]
The toner used in this example is a negatively charged toner having an average particle diameter of 6 μm, and the saturation magnetization is 205 emu / cm as the magnetic carrier.^ThreeMagnetic carrier having an average particle diameter of 35 μm was used. Further, a mixture of toner and carrier at a weight ratio of 6:94 is used as a developer.
[0119]
The developer accommodating portion 4h in which the developer circulates is divided into two by a longitudinal partition 4d except for both ends. And stirring screw 4eA, 4eB is arrange | positioned on both sides of this partition 4d.
[0120]
As shown in FIG. 4, the toner replenished from the toner replenishing container 5 falls to the back side of the agitating screw 4eB, is agitated while being sent to the front side in the longitudinal direction, and passes through a portion without the partition 4d at the front end. . Then, it is further fed to the far side in the longitudinal direction by the stirring screw 4eA, passes through a portion without the partition 4d on the far side, is stirred while being fed by the stirring screw 4eB, and is repeatedly circulated.
[0121]
Here, a developing process for visualizing the electrostatic latent image formed on the photosensitive drum 2 by the two-component magnetic brush method using the developing device 4 and a developer circulation system will be described.
[0122]
With the rotation of the developing sleeve 4a, the developer in the developing container is pumped to the surface of the developing sleeve 4a by the pumping pole of the magnet roller 4b and conveyed.
[0123]
In the process of being conveyed, the layer thickness of the developer is regulated by a regulating blade 4c arranged perpendicular to the developing sleeve 4a, and a thin layer developer is formed on the developing sleeve 4a. When the thin layer developer is transported to the developing pole corresponding to the developing portion, a spike is formed by the magnetic force. The electrostatic latent image on the surface of the photosensitive drum 2 is developed as a toner image by the toner in the developer formed in the spike shape. In this example, the electrostatic latent image is reversely developed.
[0124]
The thin layer developer on the developing sleeve 4a that has passed through the developing portion continues to enter the developing container with the rotation of the developing sleeve 4a, and is separated from the developing sleeve 4a by the repulsive magnetic field of the transport pole, and accumulates the developer in the developing container. Returned to
[0125]
A direct current (DC) voltage and an alternating current (AC) voltage are applied to the developing sleeve 4a from a power source (not shown). In this example, a DC voltage of −500 V and an AC voltage of a peak-to-peak voltage of 1500 V at a frequency of 2000 Hz are applied, and development is selectively performed only on the exposed portion of the photosensitive drum 2.
[0126]
In general, in the two-component development method, when an AC voltage is applied, the development efficiency is increased and the image becomes high quality, but there is also a risk that fog is likely to occur. For this reason, in general, it is possible to prevent fogging by providing a potential difference between the DC voltage applied to the developing sleeve 4 a and the surface potential of the photosensitive drum 2. More specifically, a bias voltage having a potential between the potential of the exposed portion of the photosensitive drum 2 and the potential of the non-exposed portion is applied.
[0127]
When the toner is consumed by development, the toner concentration in the developer decreases. In this example, a sensor 4g for detecting the toner density is disposed at a position close to the outer peripheral surface of the stirring screw 4eB. When the sensor 4g detects that the toner density in the developer has dropped below a predetermined density level, a command to replenish the toner into the developing device 4 is issued from the toner replenishing container. By this toner replenishment operation, the toner density of the developer is always maintained at a predetermined level.
[0128]
[Toner supply container]
The toner supply containers 5Y, 5M, 5C, and 5K are arranged in parallel above the process cartridges 1Y, 1M, 1C, and 1K, and are mounted from the front of the apparatus main body 100.
[0129]
As shown in FIG. 2, a stirring plate 5b fixed to the stirring shaft 5c and a screw 5a are disposed inside the toner supply container, and a discharge opening 5f for discharging the toner is formed on the bottom of the container. As shown in FIG. 5, both ends of the screw 5a and the stirring shaft 5c are rotatably supported by bearings 5d, and a drive coupling (concave) 5e is disposed at one end. The drive coupling (concave) 5e receives drive transmission from the drive coupling (convex) 62b of the apparatus main body and is driven to rotate. The outer portion of the screw 5a has a spiral rib shape, and the twisting direction of the spiral is reversed around the discharge opening 5f. The screw is rotated in a predetermined rotation direction by the rotation of the drive coupling (convex) 62b. Then, the toner is conveyed toward the discharge opening 5f, the toner is freely dropped from the opening of the discharge opening 5f, and the toner is supplied to the developing device 4 of the process cartridge.
[0130]
The tip of the stirring plate 5b in the rotational radius direction is inclined, and the tip is brought into contact with the wall of the toner supply container at a certain angle. Specifically, the tip end side of the stirring plate 5b is twisted to become a spiral state. As described above, the tip side of the stirring plate 5b is twisted and inclined to generate an axial conveying force, and the toner is sent in the longitudinal direction.
[0131]
The toner replenishing container of this example can be replenished not only in the two-component developing method but also in a process cartridge or a developing cartridge using the one-component developing method, and the powder stored in the toner replenishing container is toner Needless to say, the developer may be a mixture of toner and magnetic carrier.
[0132]
[Transfer means]
The intermediate transfer unit 54 serving as a transfer unit is configured to secondary-transfer a plurality of toner images, which are sequentially primary-transferred sequentially from the photosensitive drum 2, onto the recording medium 52 at once.
[0133]
The intermediate transfer unit 54 includes an intermediate transfer belt 54a that travels in the direction of the arrow, and travels in the clockwise direction of the arrow at a peripheral speed that is substantially the same as the peripheral speed of the photosensitive drum 2. The intermediate transfer belt 54a is an endless belt having a circumferential length of about 940 mm, and is stretched around three rollers: a drive roller 54b, a secondary transfer counter roller 54g, and a driven roller 54c.
[0134]
Further, in the intermediate transfer belt 54a, transfer charging rollers 54fY, 54fM, 54fC, and 54fK are rotatably disposed at positions facing the photosensitive drum 2, and are pressed toward the center of the photosensitive drum 2.
[0135]
The transfer charging rollers 54fY, 54fM, 54fC, and 54fK are supplied with power from a high voltage power supply (not shown), are charged with a polarity opposite to that of the toner from the back side of the intermediate transfer belt 54a, and sequentially transfer the toner images on the photosensitive drum 2 to the intermediate transfer belt 54a. Primary transfer is performed on the upper surface.
[0136]
A secondary transfer roller 54d serving as a transfer member is in pressure contact with the intermediate transfer belt 54a at a position facing the secondary transfer counter roller 54g. The secondary transfer roller 54d can swing up and down in the drawing and rotates. At the same time, since a bias is applied to the intermediate transfer belt 54a, the toner image on the intermediate transfer belt 54a is transferred to the recording medium 52.
[0137]
Here, the intermediate transfer belt 54a and the secondary transfer roller 54d are each driven. When the recording medium 52 enters the secondary transfer portion, a predetermined bias is applied to the secondary transfer roller 54d, and the toner image on the intermediate transfer belt 54a is secondarily transferred to the recording medium 52.
[0138]
At this time, the recording medium 52 sandwiched between the two is simultaneously subjected to the transfer process, and is conveyed leftward in the drawing at a predetermined speed and toward the fixing unit 56 as the next process.
[0139]
At a predetermined position of the intermediate transfer belt 54a, which is the most downstream side of the transfer process, a cleaning unit that can be brought into contact with and separated from the surface of the intermediate transfer belt 54a is provided to remove transfer residual toner remaining after the secondary transfer.
[0140]
In the cleaning unit 55, a cleaning blade 55a for removing transfer residual toner is disposed. The cleaning unit 55 is attached so as to be able to swing at a rotation center (not shown), and the cleaning blade 55a is in pressure contact with the intermediate transfer belt 54a. The transfer residual toner taken into the cleaning unit 55 is conveyed and stored in a waste toner tank (not shown) by the feed screw 55b.
[0141]
Here, as the intermediate transfer belt 54a, a belt made of polyimide resin can be used. Other materials are not limited to polyimide resin, but plastics such as polycarbonate resin, polyethylene terephthalate resin, polyvinylidene fluoride resin, polyethylene naphthalate resin, polyether ether ketone resin, polyether sulfone resin, polyurethane resin, etc. Fluorine-based or silicon-based rubber can be preferably used.
[Fixing part]
The toner image formed on the photosensitive drum 2 by the developing means is transferred onto the recording medium 52 via the intermediate transfer belt 54a. The fixing device 56 fixes the toner image transferred to the recording medium 52 to the recording medium 52 using heat.
[0142]
As shown in FIG. 1, the fixing device 56 includes a fixing roller 56a for applying heat to the recording medium 52 and a pressure roller 56b for pressing the recording medium 52 against the fixing roller 56a. Each roller is hollow. Laura. Each of them has a heater (not shown). The recording medium 52 is simultaneously conveyed by being driven to rotate.
[0143]
That is, the recording medium 52 holding the toner image is conveyed by the fixing roller 56a and the pressure roller 56b, and the toner image is fixed to the recording medium 52 by applying heat and pressure.
[0144]
The fixed recording medium 52 is discharged by discharge rollers 53h and 53j and is loaded on a tray 57 on the apparatus main body 100.
[0145]
[Installation of process cartridge and toner supply container]
Next, the mounting procedure of the process cartridge and the toner supply container will be described with reference to FIGS. 2, 3, 4, and 5. FIG. A front door 58 that can be freely opened and closed is disposed on the front of the apparatus main body 100. When the front door 58 is opened to the front, an opening for inserting the process cartridge and the toner supply container is exposed.
[0146]
A centering plate 59 that is rotatably supported is disposed in the opening for inserting the process cartridge. When the process cartridge is inserted and removed, the centering plate 59 is opened.
[0147]
In the apparatus main body 100, a guide rail 60 for guiding the mounting of the process cartridge and a guide rail 61 for guiding the mounting of the toner supply container are fixed.
[0148]
The mounting direction of the process cartridge and the toner supply container is a direction parallel to the axial direction of the photosensitive drum 2, and the guide rails 60 and 61 are also arranged in the same direction. The process cartridge and the toner supply container are once slid along the guide rails 60 and 61 from the front side in the apparatus main body 100 to the back side.
[0149]
When the process cartridge is inserted to the innermost part, the centering shaft 66 of the apparatus main body is inserted into the center hole 2f of the drum flange 2b, and the rotation center position on the inner side of the photosensitive drum 2 is determined with respect to the apparatus main body. At the same time, the drive transmission portion 2g formed on the drum flange 2b and the drive coupling (convex) 62a are connected, and the photosensitive drum 2 can be driven to rotate. The drive transmission portion 2g used in this example has a twisted triangular prism shape, and the drive force is transmitted by applying a drive force from the main body, and a force for pulling the photosensitive drum 2 to the back side is generated.
Further, a support pin 63 for positioning the process cartridge is disposed on the rear side plate 65. The support pin 63 is inserted into the frame of the process cartridge, and the position of the frame of the process cartridge is fixed.
[0150]
A rotatable centering plate 59 is disposed on the front side of the apparatus main body 100, and the bearing case 2 c of the process cartridge is supported and fixed to the centering plate 59. By these series of insertion operations, the photosensitive drum 2 and the process cartridge are positioned with respect to the apparatus main body.
[0151]
On the other hand, when the toner supply container is inserted to the innermost part, it is fixed to the support pins 64 protruding from the rear side plate 65. At the same time, the drive coupling (concave) 5e and the drive coupling (convex) 62b are connected, and the screw 5a and the stirring shaft 5c can be driven to rotate.
[0152]
  [Reference Example 1]
  Next, the charging meansReference example 1Will be explained. 6 is a schematic perspective view of a charging means adopting a cleanerless system, FIG. 7 is a schematic sectional view of the charging means, FIG. 8 is a schematic front view of the charging means, and FIG. 9 is a schematic sectional view of a brush unit of the charging means. is there.
[0153]
(Brush unit configuration of charging means)
The brush unit 3j, in which the transfer residual toner uniformizing means 3g and the toner charge amount control means 3h are unitized, fixes and supports the transfer residual toner uniformizing means 3g to the brush base 11a, and the brush base 11a is a base frame 12 made of sheet metal. In this unit, the toner charge amount control means 3h is fixedly supported to the brush base 11b, and the brush base 11b is fixed to the base frame 12. . Shafts 13a, 13b, 13c, and 3d extend from both ends of the base frame 12, and a transmission arm member 14 is attached to the shafts 13a and 13b on one side (drive side). The transfer residual toner uniformizing means 3g and the toner charge amount control means 3h are arranged at an angle so as to be in the state toward the center of the photosensitive drum 2, respectively. As described above, the transfer unit toner uniformizing unit 3g and the toner charge amount control unit 3g and the toner charge amount control unit 3h are attached to and integrated with the base frame 12, respectively. Reference numeral 3h denotes a unit that is used so that the front end portions thereof are in contact with the surface of the photosensitive drum 2.
[0154]
(Brush unit drive configuration)
The charging means 3 has a coupling gear 15 and a reciprocating cam 16 as drive transmission means at one end in the longitudinal direction, and is rotatably fitted and supported on the frame 3k of the charging means 3. The reciprocating cam 16 is composed of a cam gear 16a and a cam 16b that mesh with the coupling gear 15, and a cam groove 16c is formed by the cam gear 16a and the cam 16b, which are connected and rotate together. The protrusion 14a of the transmission arm member 14 of the brush unit 3j is fitted in the cam groove 16c. When mounted on the image forming apparatus main body, a main body coupler (not shown) is engaged with the coupling gear 15, a rotational driving force is transmitted, and the reciprocating cam 16 engaged with the coupling gear 15 rotates.
[0155]
When the reciprocating cam 16 rotates, the transmission arm member protrusion 14a of the brush unit 3j fitted in the cam groove 16c is moved in the longitudinal direction along the cam groove 16c, and reciprocates. In this example, a reciprocating motion is performed at a fixed period within a range of about 0.5 to 2.5 seconds with a stroke of 5 mm.
[0156]
(Brush fall regulation and slant configuration)
In the brush unit 3j described above, the transfer residual toner equalizing means 3g and the toner charge amount control means 3h, which are brush-like members, are directed toward the center of the photosensitive drum 2 relative to the surface of the photosensitive drum 2. When the photosensitive drum 2 rotates in the direction of the arrow in the figure (counterclockwise), the tip of the brush portion must fall along the rotation direction. If the front end part falls in the direction opposite to the rotation direction and comes into contact with the rotation of the photosensitive drum 2 in a counter state, the transfer residual toner on the photosensitive drum 2 may be scraped off. In addition, when the brush portion falls from the root of the raised portion, the density and contact pressure of the hair in contact with the contact portion with the photosensitive drum 2 is lowered, and the transfer residual toner cannot be sufficiently charged. A good image cannot be obtained.
[0157]
In view of this, in this example, the falling rib regulating rib of the brush portion and the inclined rib that reliably inclines the brush portion along the rotation direction of the photosensitive drum 2 are provided in the entire longitudinal direction.
[0158]
The hair fall regulation rib 11a2 is provided on the downstream side in the photosensitive drum rotation direction of the transfer residual toner equalizing means 3g which is a brush member and is integrally formed with the brush base 11a. When 3g falls, it keeps it from falling down from the raising part root.
[0159]
The transfer residual toner equalizing means 3g of this example has a brush hair length of 5 mm, and is suppressed by the hair fall regulation rib 11a2 from the brush raised portion root to a portion of 1 to 2 mm, and the transfer residual toner is made uniform with respect to the photosensitive drum 2. The contact state (contact density / contact pressure) of the brush tip of the means 3g is kept constant.
[0160]
The inclined rib 11a1 is provided on the upstream side in the photosensitive drum rotation direction of the transfer residual toner uniformizing means 3g, and has a rib height such that a portion of 1 to 2 mm from the root of the brushed brushed portion penetrates into the brush. The transfer residual toner uniformizing means 3g is forcibly tilted in one direction (photosensitive drum rotation direction) in the entire direction.
[0161]
In addition, the toner charge control means 3h is also provided with the inclined rib 11a3 and the hair fall regulation rib 11b1, as described above.
[0162]
As a result, when the brush unit 3j and the photosensitive drum 2 are assembled, as shown in FIG. 7, the brush front ends of the transfer residual toner uniformizing means 3g and the toner charge amount control means 3h are inclined in the rotational direction of the photosensitive drum 2 as shown in FIG. Contact with the photosensitive drum 2 is prevented, and the downstream side restricts the falling of the transfer residual toner uniformizing means 3g and the toner charge amount control means 3h to the photosensitive drum 2. The brush contact state of the transfer residual toner uniformizing means 3g and the toner charge amount control means 3h is maintained in a predetermined state.
[0163]
  [Reference Example 2]
  Next, the charging meansReference example 2Will be explained. FIG. 10 is a schematic cross-sectional view of the brush unit of the charging unit according to the second embodiment, and FIG. 11 is a schematic cross-sectional view of the charging unit according to the second embodiment.
[0164]
  This exampleReference example 1It is the structure which performed the brush hair fall regulation and inclination of the flexible sheet member using the flexible sheet member
[0165]
The flexible sheet has a sheet shape such as urethane or PET resin. In the hair fall regulation, one end side of the hair fall regulation sheet 20a is fixed to the brush base 11a and fixed, and the front end side (free end side) is close to the side surface of the brush portion of the transfer residual toner uniformizing means 3g. As for the inclination, one end side of the sheet 20b is stuck and fixed to the brush base 11a, and the leading end side (free end side) is bent and pressed against the side surface of the brush portion of the transfer residual toner uniformizing means 3g. The brush portion of the transfer residual toner uniformizing means 3g is pushed down in the rotational direction of the photosensitive drum by the contact pressure of the sheet 20b.
[0166]
Similarly to the above, the toner charge control means 3h is provided with a sheet 21b and a hair fall regulation sheet 21a.
[0167]
When the brush unit 3j and the photosensitive drum 2 are assembled, as shown in FIG. 10, a state where the transfer residual toner uniformizing means 3g and the toner charge amount control means 3h are inclined in the rotational direction of the photosensitive drum 2 by the sheets 20b and 21b on the upstream side. In contact with the rotation direction of the photosensitive drum, and prevents the transfer residual toner uniformizing means 3g and the toner charge amount control means 3h from being inclined on the downstream side. , 21b is brought into contact with the tip of the hair, and the falling of the hair is regulated, and the brush contact state of the transfer residual toner uniformizing means 3g and the toner charge amount control means 3h with respect to the photosensitive drum 2 is maintained in a predetermined state.
[0168]
  [Example 1]
  next,Example 1Will be explained. FIG.Example 1FIG. 13 is a schematic sectional view of the brush unit of the charging means according to FIG.Example 1It is a schematic sectional drawing of the charging means concerning.
[0169]
  In this example, in order to more reliably perform brush hair fall regulation and inclination,Reference example1 and 2 are combined.
[0170]
The hair fall regulation rib 11a2 is provided on the downstream side in the photosensitive drum rotation direction of the transfer residual toner equalizing means 3g which is a brush member and is integrally formed with the brush base 11a. When 3g falls, it keeps it from falling down from the raising part root.
[0171]
The inclined rib 11a1 is provided on the upstream side of the photosensitive drum rotating direction of the transfer residual toner uniformizing means, and has a rib height such that a portion of 1 to 2 mm from the root of the brushed brushed portion penetrates into the brush in the longitudinal direction. The transfer residual toner equalizing means 3g is forcibly tilted in one direction (photosensitive drum rotation direction) in the entire area.
[0172]
One end of the sheet 20b is attached and fixed to the inclined rib 11a1, the tip end is pressed against the side surface of the brush, and the brush is brought down in the photosensitive drum rotating direction by the contact pressure of the sheet 20b.
[0173]
Further, the toner charge control means 3h is also provided with the inclined rib 11a3, the hair fall regulation rib 11b1, and the sheet 21b as described above.
[0174]
As a result, when the brush unit 3j and the photosensitive drum 2 are assembled, the brush front ends of the transfer residual toner equalizing means 3g and the toner charge amount control means 3h are inclined in the rotational direction of the photosensitive drum 2 as shown in FIG. In this state, it prevents contact with the counter state with respect to the rotation direction of the photosensitive drum. On the downstream side, the transfer residual toner equalizing means 3g and the toner charge amount control means 3h regulate the falling of the hair, The brush contact state of the transfer residual toner uniformizing means 3g and the toner charge amount control means 3h is maintained in a predetermined state.
[0175]
That is, as in the above-described example, a rib and a sheet are provided on the upstream side of the brush member in the image carrier moving direction so as to be in pressure contact with the brush member and inclined in the image carrier moving direction. Further, a rib is provided on the downstream side in the moving direction of the image carrier of the brush so as to be close to the brush and restrict the falling of the brush. As a result, in the cleaner-less image forming apparatus, the contact state of the brush of the charging device having the plate-like brush member that is disposed to face the image carrier and whose tip is in contact with the surface of the image carrier is stabilized. In addition, it is possible to prevent poor charging and recovery due to toner fusion to the image carrier, toner contamination of the charging roller, and dropping of toner on the image carrier.
[0176]
[Others]
1) The charging device according to the present invention is not limited to the charging means such as the process cartridge and the image carrier of the image forming apparatus and the developer in the embodiment, and is widely disposed opposite to the member to be charged, and the tip portion is the member to be charged. This is effective as an improvement device for a charging device having a plate-like brush member in contact with the surface.
[0177]
2) The image carrier of the process cartridge or the image forming apparatus is not limited to the electrophotographic photosensitive member, and may be an electrostatic recording dielectric of an electrostatic recording process.
[0178]
3) The member to be charged (image carrier) is not limited to the drum-type rotation, but may be an endless belt body that is rotationally driven, a web-like body that is driven to travel, a plate-like body, or the like.
[0179]
【The invention's effect】
As described above, according to the present invention, for a charging device having a plate-like brush member that is disposed opposite to a member to be charged and whose tip is in contact with the surface of the member to be charged, movement of the member to be charged of the brush member is performed. By inclining a rib and a flexible sheet on the upstream side in the direction and inclining in the charged object moving direction, it is possible to prevent counter contact with the brush member charged object moving direction. For example, a cleaner-less method Therefore, in a charging device, a process cartridge, and an electrophotographic image forming apparatus provided with a brush-shaped member such as a developer charge amount control unit, the residual developer on the image carrier is prevented from being scraped off by the brush member. Is done.
[0180]
Further, the rib member on the downstream side in the moving direction of the charged member of the brush member and the flexible sheet are brought into contact with each other to restrict the falling of the hair in the moving direction of the charged member, so that the brush member contacts the moving direction of the charged member. The charging device, the process cartridge, and the electrophotographic image forming apparatus, in which the state (contact pressure, contact density) is stably maintained, for example, cleaner-less and provided with a brush-shaped member such as a developer charge amount control means In, the charge imparting to the residual developer is favorably performed.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an image forming apparatus main body in an embodiment.
FIG. 2 is a cross-sectional view of a process cartridge and a toner supply container in the embodiment.
FIG. 3 is a schematic perspective view of an image forming apparatus main body according to an exemplary embodiment.
FIG. 4 is a longitudinal sectional view of a process cartridge according to an embodiment.
FIG. 5 is a longitudinal sectional view of a toner supply container in an embodiment.
FIG. 6 is a schematic perspective view of charging means adopting the cleaner-less system in the embodiment.
[Fig. 7]Reference example 1Is a schematic cross-sectional view of the charging means
[Fig. 8]Reference example 1Schematic front view of the charging means
FIG. 9Reference example 1Brush unit schematic cross-sectional view of charging means
FIG. 10Reference example 2Brush unit schematic cross-sectional view of charging means
FIG. 11Reference example 2Is a schematic cross-sectional view of the charging means
FIG.Example 1Brush unit schematic cross-sectional view of charging means
FIG. 13Example 1Is a schematic cross-sectional view of the charging means
[Explanation of symbols]
1Y, 1M, 1C, 1K: Process cartridge
1b: Supply opening,
2: Photosensitive drum
2a: drum shaft, 2b: drum flange, 2c: bearing case, 2d: non-drive flange, 2e: bearing, 2f: center hole, 2g: drive transmission part
3: Charging device
3a: charging roller, 3b: cored bar, 3c: charging roller cleaning member,
3d: push spring, 3e: cleaning film, 3f: support member,
3g: transfer residual toner uniformizing means, 3h: toner charge amount control means, 3j: brush unit, 3k: frame
4: Development device
4a: developing sleeve, 4a1: journal part, 4b: magnet roller,
4c: regulating blade, 4d: partition wall, 4eA, 4eB: stirring screw,
4f: developer container, 4g: sensor, 4h: developer storage section, 4j: bearing,
4k: Spacer
5Y, 5M, 5C, 5K: Toner supply container
5a: screw, 5b: stirring plate, 5c: stirring shaft, 5d: bearing,
5e: Drive coupling (concave), 5f: Discharge opening
5f1: outlet cover
5f2: Holding member
5f3: Exit shutter
5f5: Opening
5f6: Seal member
11a, 11b: brush stand, 11a1, 11a3: inclined ribs,
11a2, 11b1: Hair fall regulation rib,
12: Base frame,
13a, 13b, 13c, 13d: shaft,
14: Transmission arm member, 14a: Projection
15: Coupling gear
16: Reciprocating cam, 16a: Cam gear, 16b: Cam, 16c: Cam groove,
18: Compression coil spring, 20a, 20b, 21a, 21b: Sheet
51Y, 51M, 51C, 51K: exposure means,
51a: polygon mirror, 51b: imaging lens, 51c: reflection mirror
L: Laser light
52: Recording medium
53: Feeding means
53a: feeding cassette, 53b: feeding roller, 53c: retard roller,
53d: Feeding guide, 53e, 53f: Conveying roller, 53g: Registration roller, 53h, 53j: Discharging roller
54: Intermediate transfer unit
54a: intermediate transfer belt, 54b: driving roller, 54c: driven roller,
54d: secondary transfer roller, 54fY, 54fM, 54fC, 54fK: transfer charging roller, 54g: secondary transfer counter roller
55: Transfer cleaning unit
55a: Cleaning blade, 55b: Feed screw
56: Fixing device
56a: fixing roller, 56b: pressure roller
57: Tray
58: Front door
59: Centering plate
60, 61: Guide rail
62a, 62b: Drive coupling
63, 64: Support pins
65: Rear side plate
66: Centering axis
67, 68: convex portion
100: Device main body
a: Charging part, b: Exposure part, c: Development part, d: Transfer part

Claims (10)

A plate-like brush member disposed so as to face the charged body whose surface moves, and a tip portion of which is in contact with the surface of the charged body, and the brush member on the upstream side of the charged body moving direction in the width direction of the brush member In a charging device having an inclined member for inclining the object to be charged in the moving direction,
The inclined member has a rib-shaped member that is continuously long in the longitudinal direction of the brush member, and one end of the rib-shaped member is fixed to the rib-shaped member. pressed against the upstream side is inclined to the member to be charged rotational direction the brush member, have a, a continuous long flexible sheet member in the longitudinal direction of the brush member,
The rib-shaped member presses the brush member inside the brushed region of the brush member when viewed from the brush tip end direction of the brush member to incline the brush member, and the flexible sheet member is The charging device is characterized in that a tip end side of the brush member is inclined by pressing with respect to a contact portion between the rib-shaped member and the brush member . A hair fall restricting member that restricts the brush member from falling in the moving direction from the brush base portion of the brush member due to the movement of the charged body on the downstream side of the charged body moving direction in the width direction of the brush member. The charging device according to claim 1, wherein the charging device is provided. 3. The charging device according to claim 1, wherein the rib-shaped member tilts a brush portion of the brush member in the entire longitudinal direction. 4. The charging device according to claim 1 , wherein the brush member is a charging unit that has conductivity and uniformly charges the surface of the member to be charged. The brush member is electrically conductive and transfers a developer image formed on the image carrier upstream of the charging means acting on the image carrier, which is a member to be charged, on the image carrier. claims located downstream of the transfer means for transferring, wherein the residual developer remaining on an image bearing member after the transfer step is a developer charge amount controlling means for charged to a predetermined polarity The charging device according to any one of 1 to 3 . The brush member is electrically conductive and transfers a developer image formed on the image carrier upstream of the charging means acting on the image carrier, which is a member to be charged, on the image carrier. 1 through claim, characterized in that the transferring means for transferring located downstream, the residual developer image uniformizing means for uniformizing the residual developer image remaining on the image bearing member after the transfer step 4. The charging device according to any one of 3 above. The charging device according to claim 1 , wherein the member to be charged is a rotating image carrier. The charging device according to claim 7 , wherein the image carrier is a rotating electrophotographic photosensitive member. In a process cartridge that includes at least an image carrier to be charged and a charging device that charges the image carrier, and is attachable to and detachable from the image forming apparatus main body.
9. A process cartridge, wherein the charging device is the charging device according to claim 1 . An image forming apparatus comprising an image bearing member is a member to be charged, a charging device for charging said image bearing member, and wherein the charging device is a charging device according to any one of claims 1 to 8 Image forming apparatus.

Images