JP6164935B2 - Process cartridge - Google Patents

Description

The present invention relates to a process cartridge.

  Here, the image forming apparatus forms an image on a recording medium using an appropriate image forming method such as an electrophotographic image forming method, an electrostatic recording image forming method, or a magnetic recording image forming method. Examples of the image forming apparatus include, for example, an electrophotographic copying machine, an electrophotographic printer (for example, a laser beam printer, an LED printer), a facsimile apparatus, a word processor, and a complex machine (multifunction printer), a display apparatus, and the like. included.

  The recording medium is an image on which an image is formed by an image forming apparatus, and includes, for example, recording paper, envelopes, postcards, plastic sheets, coated paper, cloth, intermediate transfer members, image display members (displays), and the like.

  The developing device is a device for converting a latent image formed on an image carrier such as an electrophotographic photosensitive member into a visible image using a developer.

  Hereinafter, for convenience, an electrophotographic image forming apparatus (hereinafter referred to as an image forming apparatus) will be described as an example. In this image forming apparatus, the process cartridge means that the charging means, the developing means or the cleaning means as the process means and the electrophotographic photosensitive drum are integrated into a process cartridge, which is detachable from the main body of the image forming apparatus. It is what.

  In addition, at least one of charging means, developing means, and cleaning means as process means and the electrophotographic photosensitive drum are integrally formed into a process cartridge so that it can be attached to and detached from the apparatus main body. Further, it means that at least the developing means and the electrophotographic photosensitive drum as process means are integrated into a process cartridge that can be attached to and detached from the apparatus main body.

  2. Description of the Related Art Conventionally, in an image forming apparatus using an electrophotographic image forming process, an electrophotographic photosensitive member as an image bearing member and process means acting on the electrophotographic photosensitive member are integrated into a process cartridge. A process cartridge system is employed in which the process cartridge is detachable from the image forming apparatus main body. According to this process cartridge system, the maintenance of the apparatus can be performed by the user himself / herself without depending on the service person, so that the operability can be remarkably improved.

  As the image forming apparatus, there is an inline type color image forming apparatus in which a plurality of process cartridges are arranged in a line. There is a contact development method in which development is performed in a state where a developing roller constituting a process cartridge is in contact with a photosensitive drum. In this system, the developing roller and the photosensitive drum during image formation are pressed against the photosensitive drum in order to maintain a predetermined contact pressure.

  In general, since the developing roller used in the contact developing method has an elastic layer, even if the developing roller is left pressed against the photosensitive drum for a long time, deformation of the elastic layer of the developing roller is reduced. Therefore, it is necessary to take measures so that image unevenness does not occur on the output image.

  Conventionally, it has been necessary to selectively use materials that are difficult to deform, or to strictly manage manufacturing conditions. In view of this, a configuration has been proposed in which the developing roller is separated from the photosensitive drum using a separation member when the process cartridge is not printed (non-image formation).

  In the configuration in which the developing roller is separated from the photosensitive drum, as in Japanese Patent Application Laid-Open No. 2003-260, a support hole that passes through a coupling pin that rotatably couples the photosensitive unit and the developing unit, one is a round hole, and the other is an elongated circle. A hole is generally used. This configuration is intended to prevent uneven contact in the longitudinal direction in consideration of dimensional variations and twists due to various factors, since the positioning reference of the developing unit is the reference pin of the round hole.

Japanese Patent Laid-Open No. 2005-43538

10 and 11, P is a process cartridge, and 10 and 20 are a drum unit and a developing unit constituting the cartridge. The drum unit 10 has a photosensitive drum 1 as an image carrier. The developing unit 20 has a developing roller 3 as a developer carrying member. The developing unit 20 is rotatably coupled to the drum unit 10 at one end side and the other end side in the unit longitudinal direction by a round hole 37a and a coupling pin 38, and an elongated round hole 37 and the coupling pin 38, respectively.

  FIG. 10A shows a state in which the developing unit 20 is moved to a contact position with respect to the drum unit 10 (position where the developing roller 3 is in contact with the photosensitive drum 1). FIG. 10B shows a state in which the developing roller 3 is moved to a separated position (a position where the developing roller 3 is separated from the photosensitive drum 1). 11A, 11B, and 11C show a process in which the developing unit 20 moves from the contact position to the separation position with respect to the drum unit 10. FIG.

  When performing development separation and contact in this configuration, the developing unit 20 is rotated about the coupling pin 38 by a driving force applied from the image forming apparatus. At this time, on the side of the round hole 37a, the driving force from the image forming apparatus is directly converted into a rotational force by the coupling pin 38 and the round hole 37a (FIG. 10). On the other hand, on the side of the oblong hole 37, the coupling pin 38 and the oblong hole 37 are loose. For this reason, the driving force from the image forming apparatus is not directly converted into a rotational force. First, linear movement is performed until the connecting pin 38 abuts on the long side end of the long round hole 37, and the long side end of the long round hole 37 is moved. After the coupling pin 38 hits the side, it is converted into a rotational force (FIG. 11).

  For this reason, the timing at which the driving force from the image forming apparatus is transmitted to the developing unit 20 is different between the round hole 37a side and the elongated round hole 37 side, and the contact and separation timings of the developing roller 3 from the photosensitive drum 1 are photosensitive. It will be different at both end positions in the body drum axis direction. Normally, the lifetimes of the developing roller 3 and the photosensitive drum 1 are determined by their contact times, and therefore the lifetimes of the developing roller 3 and the photosensitive drum 1 are calculated and set based on the long round hole 37 side having a long contact time. Is done.

  Even when the position of the developing roller varies with respect to the photosensitive drum and the developing roller axis is inclined with respect to the photosensitive drum axis, the entire width of the developing roller needs to be in contact with the photosensitive drum. For this reason, it is necessary to increase the contact pressure of the developing roller to the photosensitive drum as the position variation of the developing roller with respect to the photosensitive drum increases.

  The present invention relates to a further improvement of the above prior art. The purpose is to reduce the left-right difference between the contact and separation time at both ends in the axial direction of the image carrier when the developer carrier is brought into contact with and separated from the image carrier with a simple and inexpensive configuration. is there. This makes it possible to prolong the lifetime of the image carrier and the developer carrier.

  Another object of the present invention is to reduce the variation in the position of the developer carrier on the image carrier relative to the part production. As a result, the contact pressure of the developer carrier to the image carrier can be lowered, and deformation of the process cartridge can be suppressed.

A typical configuration of a process cartridge according to the present invention for achieving the above object is as follows:
An image carrier unit having a rotatable image carrier on which a latent image is formed;
The developer carrying in contact with said image bearing member includes a rotatable developer carrying member for developing the latent image, said developer carrying member to said image bearing member to move relative to the image carrier unit A developing unit capable of taking a contact position where the contact is made and a separated position where the contact is made;
An urging member that urges the developing unit to move from the separated position to the contact position;
A process cartridge that is detachably mounted to the main body of the image forming apparatus that forms an image on a recording medium,
Provided in the image carrier unit, and a first slide portion rotating shaft or bearing thereof of the developer carrying member is engaged slidably,
A second slide part provided in the image carrier unit, and a development unit restricting part provided in the development unit is slidably engaged ;
Have
The first slide portion is disposed at both ends of the image carrier unit in the axial direction of the image carrier, and the second slide portion is disposed at both ends of the image carrier unit in the axial direction of the image carrier. And
The rotating shaft of the developer carrier or the bearing thereof is in the first position when the developing unit is in the contact position, and is in the second position when the developing unit is in the separated position,
The developing unit restricting portion is in a third position when the developing unit is in the contact position, and is in a fourth position when the developing unit is in the separated position;
When viewed from the axial direction of the image carrier, the first slide portion is an arc-shaped elongated hole centering on the developing unit restricting portion at the fourth position, and the second slide portion is the first slide portion. An arc-shaped long hole centered on the rotation shaft of the developer carrier or its bearing at one position;
When the developing unit is in the separated position, when viewed from the axial direction of the image carrier, the urged portion urged by the urging member of the developing unit is less than the rotation shaft of the developer carrier. Is also arranged at a position away from the developing unit restricting portion .

  According to the present invention, the difference between the left and right times of the contact and separation time at both ends in the axial direction of the image carrier when the developer carrier is brought into contact with and separated from the image carrier is reduced with a simple and inexpensive configuration. It is possible. As a result, the lifetime of the image carrier and developer carrier can be extended.

  Further, it is possible to reduce the variation in the position of the developer carrying member in manufacturing the part with respect to the image carrying member. As a result, the contact pressure of the developer carrier to the image carrier can be reduced, and deformation of the process cartridge can be suppressed.

FIG. 4 is a front view of the cartridge mounted on the mounting portion of the apparatus main body in Embodiment 1, and FIGS. (A) to (d) show an operation process in which the developing unit moves from the separation position to the contact position. . Similarly, it is a rear side view of the cartridge mounted on the mounting portion of the apparatus main body, and (a) to (d) show an operation process in which the developing unit moves from the separation position to the contact position. (A) is a front perspective view of the developing unit, (b) is also a rear perspective view, and (c) and (d) are engagements of the drum cartridge and the developing unit on the front side and the back side of the cartridge, respectively. It is the perspective view which showed the relationship. 1 is a longitudinal front schematic diagram illustrating a schematic configuration of an image forming apparatus according to a first exemplary embodiment. FIG. 5 is an enlarged schematic diagram of one cartridge portion in FIG. 4, showing a state in which the developing unit is located at a contact position. FIG. 6 is a diagram illustrating a state where the developing unit is located at a contact position. In Embodiment 2, the front side of the cartridge mounted on the mounting portion of the apparatus main body is shown, (a) to (d) shows the operation process in which the developing unit moves from the separation position to the contact position. . Similarly, it is a rear side view of the cartridge mounted on the mounting portion of the apparatus main body, and (a) to (d) show an operation process in which the developing unit moves from the separation position to the contact position. (A) And (b) is the perspective view which showed the engagement relationship of the drum cartridge and the image development unit in the front side and back side of a cartridge, respectively. It is explanatory drawing by the side of the round hole of the image development contact / separation mechanism which concerns on a prior art example. It is explanatory drawing by the side of an oblong hole similarly.

[Example 1]
(Overall configuration of example image forming apparatus)
FIG. 4 is a schematic longitudinal sectional front view showing a schematic configuration of the image forming apparatus 100 of the present embodiment. The front side (front side) of the image forming apparatus 100 is the front side in the direction perpendicular to the paper surface of FIG. The opposite side is the back side (back side). Left and right are left or right when the image forming apparatus 100 is viewed from the front. The image forming apparatus 100 is an electrophotographic full-color laser beam printer that employs an inline (tandem) method and an intermediate transfer method. That is, a full color image can be formed on a sheet-like recording medium (hereinafter referred to as a recording material) S according to the electrical image information.

  Image information is acquired from the image reading apparatus connected to the image forming apparatus main body (hereinafter referred to as the apparatus main body) 100A or a host device (not shown) such as a personal computer connected to the apparatus main body 100A so as to be communicable. It is input to a control circuit unit (not shown).

  In the image forming apparatus 100, first to fourth process cartridges P (PY, PM, PC, PK) having different developer colors are respectively attached to predetermined mounting portions of the apparatus main body 100A. It is a method that can be used by detachably mounting. The apparatus main body 100A is a configuration obtained by removing the process cartridge P from the configuration of the image forming apparatus 100.

  In the present embodiment, each process cartridge P is a so-called integrated process cartridge (hereinafter referred to as a cartridge). A specific configuration of the cartridge P will be described later. Here, in this embodiment, the longitudinal direction of the cartridge P is defined as the direction of the axis of rotation of an electrophotographic photosensitive drum (hereinafter referred to as drum) 1 of the cartridge P. The front surface (front side) of the cartridge P is defined as a surface on one end side in the longitudinal direction of the cartridge P, and the back surface (rear side) is defined as a surface on the other end side.

  In the apparatus main body 100A, there are provided four process cartridge mounting portions arranged in the order from the left side to the right side in FIG. The first to fourth cartridges PY, PM, PC, and PK are mounted on the four mounting portions in order from the left side to the right side with the longitudinal direction set in the front-rear direction. More specifically, each cartridge P is detachably (removably) attached to a corresponding attachment portion via attachment means (not shown) such as an attachment guide and a positioning member provided on the apparatus main body 100A side. Yes.

  The first cartridge PY contains a yellow (Y) developer (hereinafter referred to as toner), and forms a Y toner image on the drum 1. The second cartridge PM contains magenta (M) toner and forms an M toner image on the drum 1. The third cartridge PC contains cyan (C) toner and forms a C toner image on the drum 1. The fourth cartridge PK contains black (K) toner, and forms a K toner image on the drum 1.

  Below the cartridges PY, PM, PC, and PK, there is disposed a laser scanner unit 50 for selectively exposing the drum 1 based on image information and forming a latent image corresponding to the image information on the drum 1. ing. A feeding cassette 51 that stores the recording material S is mounted below the unit 50. Further, an intermediate transfer unit 52 is disposed above the cartridges PY, PM, PC, PK as intermediate transfer means for transferring the toner image formed on each drum 1.

  The intermediate transfer unit 52 includes a driving roller 53, a secondary transfer counter roller 54, and a driven roller (tension roller) 55 as a plurality of belt support members (stretch members). These rollers are arranged in parallel to each other with the rotational axis direction being the front-rear direction. An intermediate transfer belt (hereinafter referred to as a belt) 56 as an endless belt member having flexibility is stretched between the three rollers.

  In this embodiment, the drive roller 53 is disposed on the right side of the fourth cartridge PK. The secondary transfer counter roller 54 is disposed above the drive roller 53. The driven roller 55 is disposed on the left side of the first cartridge PY. A lower (downward) belt portion between the driven roller 55 and the driving roller 53 faces the upper surface of the drum 1 of each cartridge PY, PM, PC, PK.

  Inside the belt 56, four primary transfer rollers 57 that are in pressure contact with the upper surface of the drum of each cartridge P via the lower belt portion are arranged in parallel with the rotational axis direction being the front-rear direction. Yes. As a result, in each cartridge P, the drum 1 and the belt 56 come into contact with each other to form a primary transfer nip portion (primary transfer position) N1.

  A secondary transfer roller 65 is in pressure contact with the secondary transfer counter roller 54 via a belt 56. The secondary transfer roller 65 is disposed in parallel with the secondary transfer counter roller 54 with the rotational axis direction being the front-rear direction. As a result, a secondary transfer nip portion (secondary transfer position) N2 is formed at the contact portion between the belt 56 and the secondary transfer roller 65. The primary roller 57 and the secondary roller 65 are conductive elastic rollers having the same configuration. A belt cleaning device 58 for cleaning the surface of the belt 56 is disposed on the belt suspension portion of the driven roller 55.

  An ascending conveyance path 60 for conveying the recording material S fed from the feeding cassette 51 upward is disposed on the right side in the apparatus main body 100A. A feeding roller 61, a conveying roller pair 62, a registration roller pair 63, a guide roller 64, and a secondary transfer nip portion for separating and feeding the recording material S from the cassette 51 in order from the bottom to the top along the conveying path 60. N2, an image fixing unit 66, and a discharge port 67 are provided. The transport path 60 is configured by a guide plate, a guide rib, and the like, but is omitted from the drawing. The upper surface of the apparatus main body 100A is a discharge tray 68.

  The full color image forming operation is as follows. The drums 1 of the cartridges PY, PM, PC, and PK are rotationally driven at a predetermined peripheral speed in the clockwise direction indicated by arrows. The belt 56 is also circulated and moved in the forward direction in accordance with the rotation of the drum 1 at a speed substantially corresponding to the peripheral speed of the drum 1 in the counterclockwise direction indicated by the arrow by the driving roller 53. The laser scanner unit 50 is also driven.

  In synchronism with the drive of the unit 50, a charging roller described later in each cartridge P uniformly charges the surface of the drum 1 to a predetermined polarity and potential. The unit 50 performs main scanning exposure on the surface of each drum 1 with a laser beam Z modulated in accordance with an image signal of a corresponding color at a predetermined exposure position. Thereby, an electrostatic latent image corresponding to the image signal of the corresponding color is formed on the surface of each drum 1. The latent image is developed as a toner image at a predetermined development position of the drum 1 by a developing roller of a developing unit 20 described later.

  In this embodiment, the developing unit 20 uses a non-magnetic one-component developer, that is, toner, as the developer. In this embodiment, the developing unit 20 performs reverse development by bringing a developing roller as a developer carrying member into contact with the drum 1. In other words, in this embodiment, the developing unit 20 uses a toner charged to the same polarity (negative polarity in this embodiment) as the charging polarity of the drum 1, and a portion where the charge is attenuated by exposure on the drum 1 (image portion, exposure). To develop the electrostatic image.

  By the electrophotographic image forming process operation as described above, a Y color toner image corresponding to the Y color component of the full color image is formed on the drum 1 of the first cartridge PY. The toner image is primarily transferred to the belt 56 at the primary transfer nip portion N1. An M color toner image corresponding to the M color component of the full color image is formed on the drum 1 of the second cartridge PM. The toner image is primary-transferred superimposed on the Y-color toner image already transferred to the belt 56 at the primary transfer nip portion N1.

  Further, a C color toner image corresponding to the C color component of the full color image is formed on the drum 1 of the third cartridge PC. The toner image is primary-transferred superimposed on the Y + M toner image already transferred to the belt 56 at the primary transfer nip N1. A K-color toner image corresponding to the K-color component of the full-color image is formed on the drum 1 of the fourth cartridge PK. The toner image is primary-transferred superposedly onto the Y color + M color + C color toner image already transferred to the belt 56 in the primary transfer nip portion N1.

  In the primary transfer of the toner image from the drum 1 of each cartridge P to the belt 56, a bias having a polarity opposite to the normal charging polarity of the toner is applied to the primary transfer roller 57 from a primary transfer bias power source (high voltage power source: not shown). Is done. In this manner, a four-color full-color unfixed superimposed transfer toner image of Y color + M color + C color + K color is formed on the belt 56.

  On the other hand, the recording material S is separated and fed by the feeding roller 61 from the feeding cassette 51 at a predetermined control timing, and is introduced into the conveying path 60 by the conveying roller pair 62. The recording material S is introduced into the secondary transfer nip portion N2 by the registration roller pair 63 at a predetermined control timing. As a result, in the process in which the recording material S is nipped and conveyed by the secondary transfer nip portion N2, the four-color superimposed toner images of the belt 56 are secondarily transferred in batch to the surface of the recording material S. This secondary transfer is performed by applying a bias having a polarity opposite to the normal charging polarity of the toner from a secondary transfer bias power source (not shown) to the secondary transfer roller 65.

  Then, the recording material S that has received the secondary transfer of the toner image is introduced into the image fixing unit 66 and undergoes a fixing process, and is discharged from the discharge port 67 to the discharge tray 68 as a full-color image formed product. In each cartridge P, the primary transfer residual toner on the drum 1 is removed by a cleaning member described later at a predetermined cleaning position of the drum 1. Further, the secondary transfer residual toner on the belt 56 is removed by the belt cleaning device 58.

  Note that the image forming apparatus 100 is not limited to the above-described full-color image formation, and can form a desired single-color or multi-color image. In this case, only the cartridges necessary for forming a desired single-color or multi-color image are subjected to an image forming operation, and the unnecessary cartridges are driven to rotate the drum 1 but not to perform the image forming operation. Be controlled.

(Configuration of cartridge)
In this embodiment, the configurations of the cartridges PY, PM, PC, and PK have the same configuration and shape, except that the colors of the toners stored in the cartridges are different from each other as described above. FIG. 5 is an enlarged schematic view of one cartridge portion in FIG. The cartridge P has a photoconductor unit (image carrier unit) 10 and a developing unit (developing device) 20.

  The photoconductor unit 10 has an electrophotographic photosensitive drum 1 as a rotatable image carrier on which a latent image is formed, a charging roller 2 as a process means acting on the drum 1, a cleaning frame 11, and a cleaning frame 11. The member 6 or the like is incorporated. The drum 1 is rotatably supported between a front-side drum bearing and a rear-side drum bearing, which will be described later, provided on one end side and the other end side in the longitudinal direction of the cleaning frame body 11.

  The charging roller 2 is a conductive / elastic roller as a charging unit that uniformly charges the drum 1 to a predetermined polarity and potential when a charging bias is applied. The charging roller 2 is disposed in parallel to the drum 1, and both ends of the charging roller shaft 2 a are rotatably supported by bearings 5 disposed on one end side and the other end side of the cleaning frame body 11. Yes. The bearing 5 is urged to move in a direction toward the rotation axis of the drum 1 by the pressure member 5a. As a result, the charging roller 2 is arranged in contact with the drum 1 at a predetermined charging position with a predetermined pressing force. The charging roller 2 rotates following the rotation of the drum 1.

  The cleaning member 6 is a cleaning unit that scrapes off the primary transfer residual toner from the drum surface, and is an elastic cleaning blade in this embodiment. The blade 6 is fixedly attached to the cleaning frame 11 via a support metal plate 6a, and the leading edge portion is in contact with the drum rotation direction in the counter direction at a predetermined cleaning position of the drum 1. The toner scraped off from the drum 1 by the blade 6 falls into the removed toner chamber 7 in the cleaning frame 11 and is collected.

  A flexible toner sealing member 8 that seals the gap between the removed toner chamber 7 and the drum 1 is disposed along the length of the cleaning frame 11 on the upstream side of the blade 6 in the rotation direction of the drum 1. ing. The toner sealing member 8 prevents the residual toner collected in the removed toner chamber 7 from leaking outside.

  In the developing unit 20, the developing roller 3, the toner supply roller 4, the developing blade 9, and the like are incorporated in the developing chamber 22 of the developing frame 21, and the toner is stored in the toner chamber (developer storage chamber) 23 of the developing frame 21. Is housed and configured. The developing chamber 22 is disposed above the toner chamber 23. The developing chamber 22 and the toner chamber 23 are partitioned by a partition wall 24, and a communication hole 25 is provided in the partition wall 24. A rotation shaft 26 is rotatably disposed in the toner chamber 23. The rotating shaft 26 is provided with a developer stirring / conveying member (rotating blade) 27 having flexibility.

  The developing roller 3 is a rotatable developer carrier having elasticity that carries toner and contacts the drum 1 to develop the electrostatic latent image on the drum 1 as a toner image. The developing roller 3 is arranged in parallel with the drum 1, and both end portions of the developing roller shaft 3 a are rotatably supported by bearings disposed on one end side and the other end side of the developing frame body 21. The developing roller 3 is brought into contact with the drum 1 on the photosensitive drum 10 side at a predetermined developing position with a predetermined pressing force. In this contact state, driving force is transmitted from the photosensitive unit 10 side, and at the contact portion with the drum 1, the drum 1 is rotationally driven at a predetermined peripheral speed in the counterclockwise direction of the forward arrow in the rotation direction of the drum 1.

  The toner supply roller 4 is a sponge roller that is arranged in parallel with the developing roller 3 on the side opposite to the drum 1 side of the developing roller 3 and is in contact with the developing roller 3 by entering a predetermined amount. Both ends of the shaft 4a of the roller 4 are rotatably supported by bearings provided on one end side and the other end side of the developing device frame 21. The toner supply roller 4 is rotationally driven at a predetermined peripheral speed in the counterclockwise direction of the arrow opposite to the rotation direction of the developing roller 3 at the contact portion with the developing roller 3 in conjunction with the rotational driving of the developing roller 3. . Thus, the toner is applied from the toner supply roller 4 to the developing roller 3 and supplied.

  The developing blade 9 serves to restrict the toner applied to the developing roller 3 from the toner supply roller 4 to a uniform thin layer before being conveyed to the developing position and to impart a predetermined charging polarity to the toner. The developing blade 9 is fixedly attached to the developing frame 21 via a support metal plate 9a, and the tip end portion is in contact with the developing roller 3 with a predetermined pressing force.

  A flexible toner sealing member 12 that seals the gap between the developing chamber 22 and the developing roller 3 is provided along the length of the developing frame 21 on the upstream side of the toner supply roller 4 in the rotation direction of the developing roller 3. It is arranged. The toner sealing member 12 prevents the toner in the developing chamber 22 from leaking outside.

  The rotation shaft 26 in the toner chamber 23 is driven to rotate the developer stirring and conveying member 27 in the clockwise direction of the arrow at a predetermined speed in conjunction with the rotation driving of the developing roller 3 and the toner supply roller 4. As a result, the toner stored in the toner chamber 23 is agitated, and a part of the toner in the toner chamber 23 is fed into the developing chamber 22 through the communication hole 25 and supplied to the toner supply roller 4.

  The developing unit 20 is swingably coupled to the photosensitive unit 10. That is, as shown in FIG. 5, the developing roller 3 on the developing unit 20 side contacts the drum 1 on the photoconductor unit 10 side with a predetermined pressing force at a predetermined developing position, and FIG. In such a manner, they are coupled so as to be swingable so that they can be separated from each other. The developing contact / separation mechanism (swing mechanism) of the developing unit 20 with respect to the photosensitive unit 10 will be described later.

  In a state where each cartridge P is mounted in a corresponding mounting portion in the apparatus main body 100A, the positioning portion on the photosensitive unit 10 side is changed to the positioning portion on the apparatus main body side by the pressing operation of the pressing means on the apparatus main body side. It is pressed and fixed. That is, positioning fixing means for positioning and fixing the drum unit 10 of the cartridge P to a predetermined position is provided in the process cartridge mounting portion corresponding to each cartridge P in the apparatus main body 100A. As the positioning and fixing means, various means configurations are known, and are omitted from the drawing.

  The driving coupling portion on the apparatus main body 100A side is coupled to the driven coupling portion on the photosensitive unit 10 side that is positioned and fixed. As a result, a driving force can be transmitted to each cartridge P from the driving unit (driving motor) on the apparatus main body 100A side. Further, the power feeding unit on the apparatus main body 100A side is electrically coupled to the power receiving unit on the photoconductor unit 10 side. As a result, a predetermined bias such as a charging bias and a developing bias can be applied to each cartridge P from the power supply unit on the apparatus main body 100A side.

  In the above, the pressing means, the non-positioning part, the positioning part, the driven coupling part, the driving coupling part, the power receiving part, the power feeding part, the driving part, and the power supply part are omitted in the drawing.

  In each cartridge P, the developing unit 20 can swing with respect to the photosensitive unit 10 that is positioned and fixed to the mounting portion of the apparatus main body 100A. Oscillation is selectively controlled to the separation position B in FIG.

  That is, during the image forming operation in the full color mode of the image forming apparatus 100, the developing unit 20 of each cartridge PY, PM, PC, PK is changed to the contact position A in FIG. 5 and the full color image forming operation is executed. During non-image formation (the drum 1 and the belt 56 may or may not be driven), the developing units 20 of the cartridges PY, PM, PC, and PK are converted to the separation position B in FIG. Held in a state.

  Further, during an image forming operation in a mode for forming a desired single color or multi-color image, the developing unit 20 is switched to the contact position A only for a cartridge necessary for forming a desired single-color or multi-color image. The image forming operation is performed. For the unnecessary cartridge, the drum 1 is driven to rotate, but the developing unit 20 is held at the separation position B and controlled so as not to perform the image forming operation.

(Development contact / separation mechanism)
The developing contact / separation mechanism of the cartridge P in this embodiment will be described below. FIG. 1A is a front view of the cartridge P when it is attached to the attachment portion of the apparatus main body 100A and the developing unit 20 is converted to the separation position B. FIG. FIG. 2A is a rear view of the cartridge P. FIG. The developing contact / separation mechanism is arranged in the same configuration symmetrically on the front side and the back side of the cartridge P and performs the same operation.

In the photoreceptor unit 10, the drum 1 is fixed to one end side and the other end side in the longitudinal direction of the cleaning frame body 11, and is provided with a front side drum bearing and a rear side as an image carrier bearing (image carrier bearing member). Between the side drum bearings 31 (31F, 31R), it is rotatably supported and arranged. The two bearings 31 are provided with a first development positioning portion (first slide portion) 32 (32F, 32R) and a spring hook pin 33 (33F, 33R) as a developer carrier restricting portion symmetrically. .

Further, a second development positioning portion (second slide portion) 34 as an image carrier unit restricting portion is symmetrically provided in the middle portion in the height direction of the front plate and the back plate 13 (13F, 13R) of the cleaning frame 11. (34F, 34R) are provided.

  On the other hand, in the developing unit 20, the front plate and the back plate 26 (26F, 26R) of the developing frame 21 are respectively connected to one end of the developing roller shaft 3a on the outer side thereof as shown in FIGS. And the other end project. Alternatively, a bearing that rotatably supports one end and the other end of the developing roller shaft 3a may be projected. In this embodiment, the developing roller shaft 3a or its bearing is used as a positioning reference for the developing unit 20.

Further, a developing unit holder 27 (27F, 27R) is provided on the front plate 26F and the back plate 26R of the developing frame 21 so that a part of the middle in the height direction protrudes symmetrically in the direction toward the photosensitive unit 10. It is. An outward engagement shaft 28 (28F, 28R) as a developing unit restricting portion is provided symmetrically at the front end side of each holder 27. Further, symmetrically, spring-hanging pins (biased portions) 29 (29F, 29R) are provided on the upper portions of the front plate 26F and the rear plate 26R of the developing device frame 21, respectively.

  The first developing positioning portion 32F and one end portion of the developing roller shaft 3a or its bearing are engaged on the front side of the cartridge P. Further, the second development positioning portion 34F and the engagement shaft 28F are engaged. Further, on the back side of the cartridge P, the first developing positioning portion 32R and one end portion of the developing roller shaft 3a or its bearing are engaged. Further, the second development positioning portion 34R and the engagement shaft 28R are engaged. FIGS. 3C and 3D are perspective views showing the above-described engagement relationship between the front side and the back side of the cartridge P, respectively.

  The first development positioning portion 32 is an arc-shaped elongated hole that is substantially centered on the engagement shaft 28 engaged with the second development positioning portion 34, and the end of the developing roller shaft 3a is engaged with the elongated hole. Can be slid along the long hole. Although details will be described later, the position of the developing roller 3 with respect to the drum 1 changes as the developing roller shaft 3 a slides on the first developing positioning portion 32.

  Further, the second development positioning portion 34 is a short arc-shaped long hole centered on the developing roller shaft 3a engaged with the first development positioning portion 34, and the engagement shaft 28 is engaged with the long hole. doing. The elongated hole as the second development positioning portion 32 has a flaw hole configuration (engagement) that does not come into contact with the engagement shaft 28 except for the separation positioning portion 32a1 that is one end of the elongated hole and the contact positioning portion 32a2 that is the other end. The hole is larger than the outer diameter of the shaft 28.

  By the engagement between the first development positioning portion 32 and one end portion of the developing roller shaft 3a or its bearing and the engagement between the second development positioning portion 34 and the engagement shaft 28, the developing unit is connected to the photosensitive unit 10. 20 is assembled so as to be swingable.

  Further, on the front side and the back side of the cartridge P, a tension and pressure spring 35 (35F, 35R) as a biasing member is provided between the spring hooking bin 33 on the photoconductor unit 10 side and the spring hooking bin 29 on the developing unit 20 side. ) Is stretched. As a result, the developing unit 20 is attracted to the photosensitive drum 10 side and is always oscillated and biased in the direction in which the developing roller 3 contacts the drum 1. That is, an urging member 35 is provided between the drum unit 10 and the developing unit 20 to move and urge in a direction characterized by satisfying the condition that the developing unit 20 is in the contact position A.

  In the cartridge P mounted on the mounting portion of the apparatus main body 100A, the photosensitive unit 10 is positioned and fixed at the positioning portion on the apparatus main body 100A side. The developing unit 20 is in contact with the photoconductor unit 10 by the above-described developing contact / separation mechanism so that the developing roller 3 is in contact with the drum 1 at a predetermined development position with a predetermined pressing force as shown in FIG. It can swing to the contact position A and the separation position B in the separated state as shown in FIG.

  In this embodiment, the relative position between the second development positioning portion 34 and the engaging shaft 28 and the relative position between the first development positioning portion 32 and the developing roller shaft 3a are changed so that the developing unit 20 comes into contact with the separated position. Can move to a position. In other words, in conjunction with the movement of the developing unit 20 to the separation position and the contact position, the relative position between the second development positioning portion 34 and the engagement shaft 28 and the first development positioning portion 32 and the developing roller shaft. The relative position of 3a changes.

1A and 2A show a state where the developing unit 20 of the cartridge P is held at the separation position B when the image forming apparatus 100 is not forming an image. In this state, the developing separation lever 40 on the apparatus main body 100A side moves forward. As a result, the developing separation rib (force receiving portion) 21a disposed at the lower part of the developing device frame 21 of the developing unit 20 has a predetermined direction in the direction toward the photosensitive unit 10 against the tension of the tension and pressure spring 35. It has been pushed to the first position X.

  The engagement shaft 28 is pressed against the separation positioning portion 32 a 1 which is one end of the second development positioning portion 32 by the pushing movement force of the developing unit 20 and the tension of the tension and pressure spring 35. Thereby, the position of the developing unit 4 is determined. The developing unit 20 rotates about the engaging shaft 28 in the direction in which the developing roller 3 is separated from the drum 1. The end portion of the developing roller shaft 3a is slid and moved within a hole length as the first developing positioning portion 32 to a position that is a predetermined distance away from the drum 1.

  The development separation lever 40 is driven by a drive mechanism (not shown) controlled by a control circuit section, and the first position X is moved forward, and the development separation lever 40 is moved backward from the first position X and separated from the development separation rib 21a. Movement between the positions Y is controlled. In this embodiment, the developing separation lever 40 is a developing unit shift means for selectively moving the developing unit 20 from the contact position A to the separation position B and from the separation position B to the contact position A. Such a developing unit shift means can be appropriately configured by an electromagnetic solenoid mechanism, a cam mechanism, a reciprocating mechanism, etc. controlled by a control circuit section, and is not shown in the drawing.

  When the image forming apparatus 100 forms an image, the developing unit 20 of the cartridge P is in a state in which the developing roller 3 is brought into contact with the drum 1 from the separation position B with a predetermined pressing force at a predetermined developing position as shown in FIG. Is moved to the contact position A. The operation of the developing contact / separation mechanism in the process in which the developing unit 20 moves from the separation position B to the contact position A will be described.

  An arrow G separating the developing separation lever 40 located at the first position X as shown in FIGS. 1 (a) and 2 (a) from the developing separation rib 21a as shown in FIGS. 1 (b) and 2 (b). It is gradually moved backward in the direction. At this time, the urging force of the tension and pressure spring 35 acts to attract the developing unit 20 to the photoreceptor unit 10. For this reason, the development separation rib 21 a moves backward in the G direction while contacting the development separation lever 40 as the development separation lever 40 moves backward.

  Accordingly, the developing unit 20 is pressed against the separation positioning portion 32a1 that is one end of the second development positioning portion 32. The developing roller 3 rotates around the engagement shaft 28 in a direction in which the developing roller 3 comes into contact with the drum 1. That is, since the shape of the first developing positioning portion 32 provided on the drum bearing 31 is a concentric arc shape with the engaging shaft 28 as the center, the developing unit 20 has the developing roller shaft 3a with the engaging shaft 28 as the center. , And the end portion of the shaft rotates in the direction of arrow H while engaging the first positioning portion 32.

  Thereafter, the developing roller 3 gradually approaches the drum 1 and finally the developing roller 3 comes into contact with the drum 1. Further, since the urging force of the tension and pressure spring 35 continues to act to attract the developing unit 20 to the photosensitive unit 10, the engagement shaft 28 is kept in contact with the separation positioning portion 34a1. .

  Even when the developing separation lever 40 further moves in the direction of arrow G with the developing roller 3 in contact with the drum 1, the urging force of the tension and pressure spring 35 still acts to attract the developing unit 20 to the photosensitive unit 10. I keep doing it. Therefore, the developing unit 20 rotates around the end of the developing roller shaft 3a in the direction of arrow I in FIGS. 1C and 2C. At this time, the development separation lever 40 and the development separation rib 21a are still in contact with each other.

  When the developing unit 20 further rotates about the developing roller shaft 3a in the direction of the arrow I, the engaging shaft 28 contacts the contact positioning portion 34a2 of the second developing positioning portion 34, and the position of the developing unit 20 is fixed. . At this time, the development separation lever 40 is still in contact with the development separation rib 21a.

  Further, the development separation lever 40 moves backward in the direction of arrow G, and stops moving at the second position Y away from the development separation rib 21a as shown in FIGS. 1 (d) and 2 (d). To do. In this state, the cartridge P is located at the contact position A in a state where the developing unit 20 contacts the developing roller 3 with respect to the drum 1 with a predetermined pressing force at a predetermined developing position with respect to the photosensitive unit 10. Image forming operation can be performed.

  When the developing unit 20 reaches the contact position A, at least one side of the developing unit 20 is fixed by the engagement shaft 28 coming into contact with the contact positioning portion 34a2, so that the developing separation lever 40 and the developing separation rib 21a are not spaced from each other. There will be a state. Further, the developing roller 3 is urged by the tension and pressure spring 35 so as to always contact the drum 1 with a predetermined pressing force.

  Next, the state in which the developing unit 20 shifts from the contact position A at the time of image formation to the separation position B at the time of non-image formation is reverse to the state in which the development unit 20 shifts from the separation position B to the contact position A. Is called. That is, when the image formation is completed, the developing separation lever 40 moves in the direction opposite to the arrow G direction to move forward from the second position Y to the first position X ((d) in FIG. 1, ( d) → (c) in FIG. 1, (c) in FIG.

  When the development separation lever 40 contacts the development separation rib 21a and then moves further in the direction opposite to the arrow G direction, the development unit 20 rotates in the direction opposite to the arrow I direction around the end of the development roller shaft 3a. ((C) in FIG. 1, (c) in FIG. 2 → (b) in FIG. 1, (b) in FIG. 2)). When the developing separation lever 40 further moves in the direction opposite to the arrow G direction, the engagement shaft 28 contacts the separation positioning portion 34a1 of the second development positioning portion 34 ((b) in FIG. 1, (b) in FIG. 2). .

  When the developing separation lever 40 further moves in the direction opposite to the arrow G direction, the developing unit 20 rotates about the engaging shaft 28 in the direction opposite to the arrow H direction, and the developing roller 3 is separated from the drum 1 ( (B) in FIG. 1, (b) in FIG. 2, (a) in FIG. 1, (a) in FIG. 2). At this time, since the separation positioning portion 34a1 that contacts the engagement shaft 28 is set at the same position on the front side and the back side in the axial direction of the drum 1, the timing at which the developing roller 3 is separated from the drum 1 is the front side. The timing is the same on the back side.

  Further, when the developing separation lever 40 moves forward in the direction opposite to the arrow G direction and reaches the first position X, the developing unit 20 rotates about the engagement shaft 28 in the direction opposite to the arrow H direction to move to the separation position B. (FIG. 1 (a), FIG. 2 (a)).

  In this embodiment, the tension and pressure spring 35 disposed in the cartridge P is used as the biasing means as a means for moving the developing unit 20 to the separation position B and the contact position A. However, the present invention is not limited to this. Alternatively, a compression spring or a torsion coil spring may be used. Similarly, the cartridge P may not have this urging means, but may have the same urging means on the apparatus main body 100A side.

In the present embodiment, the shape of the first developing positioning portion 32 provided on the drum bearing 31 is a concentric arc shape with the engaging shaft 28 as the center. However, the shape is not limited to this and may be a linear shape.
In this embodiment, the developing roller shaft 3a is engaged with the drum bearing 31 to determine the position of the developing unit 20. However, the present invention is not limited to this, and a bearing member provided coaxially with the developing roller shaft 3a. The position of the developing unit 20 may be determined by engaging and moving.

  As described above, according to this embodiment, the difference between the contact and separation time at both ends in the drum axial direction can be reduced when the developing roller 3 contacts and separates from the drum 1. Thus, the life of the developing roller 3 and the drum 1 can be extended. Further, it is possible to reduce the positional variation in manufacturing the parts of the developing roller 3 with respect to the drum 1, it becomes possible to reduce the contact pressure of the developing roller 3 to the drum 1, and the deformation of the cartridge P can be suppressed. .

[Example 2]
7 to 9 are diagrams showing the configuration of the cartridge P in the second embodiment. FIG. 7 is a front view of the cartridge P mounted on the mounting portion of the apparatus main body in the second embodiment. (A) to (d) show an operation process in which the developing unit 20 moves from the separation position B to the contact position A, and corresponds to (a) to (d) of FIG.

  FIG. 8 is also a view of the back side of the cartridge P mounted on the mounting portion of the apparatus main body. FIGS. 2A to 2D show an operation process in which the developing unit moves from the separated position to the contact position, and corresponds to FIGS. 2A to 2D in the first embodiment. FIGS. 9A and 9B are perspective views showing the engagement relationship between the drum cartridge and the developing unit on the front side and the back side of the cartridge, respectively. This corresponds to (c) and (d) of FIG.

  In the second embodiment, the second development positioning portion 34 (34F, 34R) as the image carrier unit regulating portion is provided in the front drum bearing 31 and the rear drum bearing 31 (31F, 31R) as the image carrier bearing. It is. Since the other configuration of the cartridge P, the operation and effect of the cartridge P, the configuration of the image forming apparatus, and the like are the same as those in the first embodiment, the description thereof will be omitted.

[Other matters]
1) In the embodiment, the image forming apparatus is a color image forming apparatus. However, the present invention is not limited to such a color image forming apparatus, and may be a monocolor image forming apparatus, and can be applied to various other image forming apparatuses.

  2) The image forming method of the image forming apparatus is not limited to the electrophotographic image forming method. A latent image is formed on the image carrier by other image forming principle methods such as an electrostatic recording image forming method using an electrostatic recording dielectric as an image carrier and a magnetic recording image forming method using a magnetic recording magnetic material, and a developer. Any suitable image forming method for development can be used.

  100..Image forming apparatus, 100A..Main body, P..Process cartridge, 10..Image carrier unit, 1 .... Image carrier, 20..Development unit, 3.Developer carrier, 3a. ..Rotary shaft, S..recording medium, 31..image carrier bearing, 32..developer carrier regulating section, 28..developing unit regulating section

Claims (6)

An image carrier unit having a rotatable image carrier on which a latent image is formed;
The developer carrying in contact with said image bearing member includes a rotatable developer carrying member for developing the latent image, said developer carrying member to said image bearing member to move relative to the image carrier unit A developing unit capable of taking a contact position where the contact is made and a separated position where the contact is made;
An urging member that urges the developing unit to move from the separated position to the contact position;
A process cartridge that is detachably mounted to the main body of the image forming apparatus that forms an image on a recording medium,
Provided in the image carrier unit, and a first slide portion rotating shaft or bearing thereof of the developer carrying member is engaged slidably,
A second slide part provided in the image carrier unit, and a development unit restricting part provided in the development unit is slidably engaged ;
Have
The first slide portion is disposed at both ends of the image carrier unit in the axial direction of the image carrier, and the second slide portion is disposed at both ends of the image carrier unit in the axial direction of the image carrier. And
The rotating shaft of the developer carrier or the bearing thereof is in the first position when the developing unit is in the contact position, and is in the second position when the developing unit is in the separated position,
The developing unit restricting portion is in a third position when the developing unit is in the contact position, and is in a fourth position when the developing unit is in the separated position;
When viewed from the axial direction of the image carrier, the first slide portion is an arc-shaped elongated hole centering on the developing unit restricting portion at the fourth position, and the second slide portion is the first slide portion. An arc-shaped long hole centered on the rotation shaft of the developer carrier or its bearing at one position;
When the developing unit is in the separated position, when viewed from the axial direction of the image carrier, the urged portion urged by the urging member of the developing unit is less than the rotation shaft of the developer carrier. Is disposed at a position away from the developing unit restricting portion . In the process in which the developing unit moves from the separated position to the contact position by the urging force of the urging member, the developing unit remains in the state where the developing unit restricting portion is in the fourth position. After the rotating shaft of the carrier or the bearing thereof moves from the second position to the first position, the developing unit restricting portion remains in the state where the rotating shaft of the developer carrier or the bearing thereof is in the first position. The process cartridge according to claim 1, wherein the cartridge moves from the fourth position to the third position. The image carrier unit includes an image carrier bearing member including a bearing portion that rotatably supports the image carrier,
The process cartridge according to claim 1, wherein the first slide portion is provided on the image carrier bearing member. The process cartridge according to claim 3, wherein the second slide portion is provided on the image carrier bearing member . It said image bearing member is an electrophotographic photosensitive drum, process cartridge according to any one of claims 1 to 4 wherein the developer carrying member is characterized in that it is a developing roller. The said developing unit has a force receiving part which receives the force which resists the urging | biasing force of the said urging | biasing member at the said separation position, The said developing unit is characterized by the above-mentioned. The described process cartridge.