IMAGE FORMING APPARATUS, PROCESS CARTRIDGES, AND CONNECTING MEMBER

[Task] To further develop conventional technique. [SOLUTION] An image forming apparatus includes a main assembly; a plurality of process cartridges detachably mountable to the main assembly. The process cartridges each includes a photosensitive member, a first frame rotatably supporting the photosensitive member, a developing member for depositing toner onto the photosensitive member, and a second frame rotatably supporting the developing member and movable relative to the first frame between a developing position for the developing member to deposit the toner onto the photosensitive member and a retracted position in which the developing member is more remote from the photosensitive member than in the developing position. The apparatus further includes a connecting member 201 connecting at least two of the second frames of the process cartridges and removable from at least one of the process cartridges and from the main assembly.

TECHNICAL FIELD

The present invention relates to an electrophotographic image forming apparatus such as a copying machine or a printer which employs an electrophotographic method, and to a cartridge and a connecting member usable with the electrophotographic image forming apparatus.

Here, an electrophotographic image forming apparatus (hereinafter also referred to as an “image forming apparatus”) forms an image on a recording material using an electrophotographic image forming process. Examples of the image forming apparatuses include a copying machine, a facsimile machine, a printer (laser beam printer, LED printer, and so on), and a multifunction machine (multifunction printer). A cartridge is a device which integrally includes at least a device (developing device), as process means actable on an electrophotographic photosensitive member (hereinafter referred to as a “photosensitive drum”), for visualizing, using a developer, an electrostatic latent image formed on the electrophotographic photosensitive member by an electrophotographic image forming process, the cartridges being mountable to and dismountable from a main assembly of the image forming apparatus. A connecting member is a member four connecting a plurality of developing devices usable with a color image forming apparatus.

BACKGROUND OF THE INVENTION

Conventionally, in an image forming apparatus using an electrophotographic forming process, an electrophotographic photosensitive member (hereinafter referred to as a photosensitive drum) and process means actable on the photosensitive drum are integrated into a cartridge. A process cartridge system is employed in which the cartridge is mountable to and dismountable from the main assembly of the image forming apparatus. In this process cartridge system, the maintenance of the image forming apparatus can be performed, in effect, by the user himself/herself without relying on service personnel, so that the maintainability can be improved remarkably. Therefore, the process cartridge system is widely used with image forming apparatuses. A conventional process cartridge comprises a drum unit including a drum frame which holds the photosensitive drum, and a developing unit including a developing roller as means for developing the latent image on the photosensitive drum, a developing blade, and toner as a developer.

There is known an image forming apparatus called an in-line system in which a plurality of process cartridges are arranged. This in-line image forming apparatus includes the process cartridges including photosensitive drums and developing units for respective colors of yellow, magenta, cyan, and black, and superimposes images of these colors to form a full-color image. When the image is formed, the developing roller is contacted with the photosensitive drum with a predetermined pressure. In the contact development method in which the developing roller is in contact with the photosensitive drum for development, the developing roller is in contact with the surface of the photosensitive drum with a predetermined pressure. For example, there a case that a developing roller having an elastic layer is used and the elastic layer is brought into contact with the surface of the photosensitive, and if the developing roller is not used for a long period of time in such a case, the elastic layer of the developing roller may be deformed. This may cause image unevenness during developing operation.

As another example, regardless of the presence or absence of the elastic layer, if the developing roller is in contact with the photosensitive drum during non-image formation, the case may be that the developer carried by the developing roller will unnecessarily adhere to the photosensitive drum. As a further example, if the photosensitive drum and the developing roller rotate in contact with each other during the time without developing operation, deterioration of the photosensitive drum, the developing roller and the developer may be accelerated, due to the rubbing between the photosensitive drum and the developing roller. Therefore, in JP-A-2007-213024 and JP-A-2014-067005 discloses a structure of a main assembly of an image forming apparatus which comprises a mechanism which acts on the process cartridge to provide a space between the photosensitive drum and the developing roller when image formation is not performed.

SUMMARY OF THE INVENTION

Problem to be Solved

However, the conventional techniques described in JP-A-2007-213024 and JP-A-2014-067005 still have room for further improvement. Therefore, an object of the present disclosure is to further develop the conventional technology.

Means for Solving the Problem

In order to solve the above-described problems, the image forming apparatus disclosed herein comprises;

a main assembly;

a plurality of process cartridges detachably mountable to the main assembly, the process cartridges each including,

a photosensitive member,

a first frame rotatably supporting the photosensitive member,

a developing member for depositing toner onto the photosensitive member, and

a second frame rotatably supporting the developing member and movable relative to the first frame between a developing position for the developing member to deposit the toner onto the photosensitive member and a retracted position in which the developing member is more remote from the photosensitive member than in the developing position; and

a connecting member connecting at least two of the second frames of the process cartridges and removable from at least one of the process cartridges and from the main assembly.

Effect of the Invention

According to the present disclosure, the prior art can be further developed.

DESCRIPTION OF EMBODIMENTS

The embodiments of the present invention will be exemplarily described in detail in conjunction with the drawings. However, the dimensions, materials, shapes and relative arrangement of the components described in this embodiment should be appropriately changed according to the structure of the device to which the invention is applied and various conditions. That is, it is not intended to limit the scope of the present invention to the following embodiments.

Embodiment 1 of the present disclosure will be described with reference to the drawings. In the following embodiments, an image forming apparatus to which four process cartridges (cartridges) can be mounted and dismounted is exemplified as an image forming apparatus. The number of process cartridges to be mounted on the image forming apparatus is not limited to this example. It is appropriately selected as needed. Further, in the embodiments described below, a laser beam printer is exemplified as one aspect of the image forming apparatus.

[Schematic Structure of Image Forming Apparatus]

FIG.2is a schematic cross-sectional view of the image forming apparatus M.FIG.3is a sectional view of the process cartridge100. This image forming apparatus M is a four-color full-color laser printer using an electrophotographic process, and forms a color image on a recording material S. The image forming apparatus M is of a process cartridge type, and forms a color image on a recording material S using the process cartridges dismountably mounted in the image forming apparatus main assembly170.

Here, regarding the image forming apparatus M, the side on which the front door11is provided is the front side (front side), and the side opposite to the front side is a back side (rear side). The right side of the image forming apparatus M is called drive-side, and the left side thereof is called non-drive-side. Also, as the image forming apparatus M is viewed from the front side, the upper side is the upper surface, and the lower side is the lower surface.FIG.2is a sectional view of the image forming apparatus M as viewed from the non-drive-side, wherein front side of the sheet of the drawing is the non-drive-side of the image forming apparatus M, and the right side of the sheet of the drawing is the front side of the image forming apparatus M, and the back side of the sheet of the drawing is the dive-side of the image forming apparatus M. The drive-side of the process cartridge100is the side on which a drum coupling member (photosensitive member coupling member), which will be described hereinafter, is provided as viewed in the axial direction of the photosensitive drum. In addition, the drive-side of the process cartridge100is the side on which a development coupling member, which will be described hereinafter, is provided as viewed in the axial direction of the developing roller (developing member).

The image forming apparatus main assembly170includes a first process cartridge100Y including a separation and contact mechanism150which will be described hereinafter, a second process cartridge100M not including the separation and contact mechanism150, a third process cartridge100C not including the separation and contact mechanism150, a fourth process cartridge100K including the separation and contact mechanism150, wherein the four process cartridges100(100Y,100M,100C, and100K) are arranged substantially horizontally.

Each of the first to fourth process cartridges100(100Y,100M,100C, and100K) has a similar electrophotographic process mechanism, and uses different colors of developer (hereinafter referred to as toner). A rotational drive force is transmitted from a drive output portion (details will be described hereinafter) of the image forming apparatus main assembly170to the first to fourth process cartridges100(100Y,100M,100C,100K). A bias voltage (charging bias, developing bias, and so on) is supplied from the image forming apparatus main assembly170to each of the first to fourth process cartridges100(100Y,100M,100C,100K) (not shown).

As shown inFIG.3, each of the first to fourth process cartridges100(100Y,100M,100C,100K) of this embodiment includes a drum unit108a photosensitive drum104and charging means as the process means actable on the photosensitive drum104. Here, the drum unit may have not only charging means but also cleaning means as the process means. Each of the first to fourth process cartridges100(100Y,100M,100C,100K) has a developing unit109including developing means for developing the electrostatic latent image on the photosensitive drum104. The drum unit108and developing unit109are coupled together. A more specific structure of the process cartridge100will be described hereinafter.

The first process cartridge100Y accommodates yellow (Y) toner in the developing unit frame125and forms a yellow toner image on the surface of the photosensitive drum104. The second process cartridge100M accommodates magenta (M) toner in the developing unit frame125and forms a magenta toner image on the surface of the photosensitive drum104. The third process cartridge100C accommodates cyan (C) toner in the developing unit frame125and forms a cyan toner image on the surface of the photosensitive drum104. The fourth process cartridge100K accommodates black (K) toner in the developing unit frame125and forms a black toner image on the surface of the photosensitive drum104. The developing unit109of the first process cartridge100Y, the developing unit109of the second process cartridge100M, and the developing unit109of the third process cartridge100C are connected by a connecting member201, which will be described hereinafter.

A laser scanner unit14as exposure means is provided above the first to fourth process cartridges100(100Y,100M,100C,100K). This laser scanner unit14outputs a laser beam U corresponding to image information. Then, the laser beam U passes through the exposure window110of the process cartridge100and scans and exposes the surface of the photosensitive drum104.

An intermediary transfer unit12as a transfer member is provided below the first to fourth process cartridges100(100Y,100M,100C,100K). The intermediary transfer unit12includes a drive roller12e, a turn roller12c, a tension roller12b, around which a flexible transfer belt12astretched. The lower surface of the photosensitive drum104of each of the first to fourth process cartridges100(100Y,100M,100C,100K) is in contact with the upper surface of the transfer belt12a. The contact portion is a primary transfer portion. A primary transfer roller12dis provided inside the transfer belt12aso as to oppose the photosensitive drum104. A secondary transfer roller6is opposed to the turn roller12cwith the transfer belt12ainterposed therebetween. A contact portion between the transfer belt12aand the secondary transfer roller6is a secondary transfer portion.

A feeding unit4is provided below the intermediary transfer unit12. The feeding unit4includes a sheet feeding tray4ain which recording materials S are accommodated in a stack, and includes a sheet feeding roller4b. A fixing device7and a paper discharge device8are provided in the upper left portion of the image forming apparatus main assembly170in the Figure. The upper surface of the image forming apparatus main assembly170is used as a paper discharge tray13. A toner image is fixed on the recording material S by fixing means provided in the fixing device7, and the recording material S is discharged to the paper discharge tray13.

The operation for forming a full-color image is as follows. The photosensitive drums104of the first to fourth process cartridges100(100Y,100M,100C,100K) are rotationally driven at a predetermined speed (in the direction of arrow A inFIG.3). The transfer belt12ais also rotationally driven at a speed corresponding to the speed of the photosensitive drum104codirectionally (arrow C direction inFIG.2) with the photosensitive drum104. The laser scanner unit14is also driven. In synchronism with the driving of the laser scanner unit14, the charging roller105in each process cartridge uniformly charges the surface of the photosensitive drum104to a predetermined polarity and potential. The laser scanner unit14scans and exposes the surface of each photosensitive drum104with laser beam U in accordance with the image signal of each color. By this, an electrostatic latent image corresponding to the image signal of the corresponding color is formed on the surface of each photosensitive drum104. The formed electrostatic latent image is developed by a developing roller106which is rotationally driven at a predetermined speed.

A yellow toner image corresponding to the yellow component of the full-color image is formed on the photosensitive drum104of the first process cartridge100Y by the electrophotographic image forming process operation as described above. Then, the toner image is primarily transferred onto the transfer belt12a. Similarly, a magenta toner image corresponding to the magenta component of the full-color image is formed on the photosensitive drum104of the second process cartridge100M. Then, the toner image is primarily transferred so as to be superimposed on the yellow toner image which has already been transferred onto the transfer belt12a. Similarly, a cyan toner image corresponding to the cyan component of the full-color image is formed on the photosensitive drum104of the third process cartridge100C. Then, the toner image is primarily transferred so as to be superimposed on the yellow and magenta toner images which have already been transferred onto the transfer belt12a. Similarly, a black toner image corresponding to the black component of the full-color image is formed on the photosensitive drum104of the fourth process cartridge100K. Then, the toner image is primarily transferred so as to be superimposed on the yellow, magenta, and cyan toner images which have already been transferred onto the transfer belt12a. In this manner, an unfixed full-color toner image of four colors of yellow, magenta, cyan, and black is formed on the transfer belt12a.

On the other hand, a recording material S is separated and fed one by one at a predetermined control timing. The recording material S is introduced to the secondary transfer portion, which is the contact portion between the secondary transfer roller6and the transfer belt12a, at a predetermined control timing. By this, the four-color superimposed toner image on the transfer belt12ais continuously transferred onto the surface of the recording material S all at once while the recording material S is fed to the secondary transfer portion. In more detail, the structure of the main assembly of the image forming apparatus will be described below.

Referring toFIGS.1and4to7, a tray (hereinafter referred to as tray)171for supporting the process cartridge will be described in more detail.FIG.4is a sectional view of the image forming apparatus M in which the tray171is positioned inside the image forming apparatus main assembly170with the front door11open.FIG.5is a sectional view of the image forming apparatus M with the front door11opened, the tray171positioned outside the image forming apparatus main assembly170, and the process cartridges100are accommodated in the tray.FIG.6is a sectional view of the image forming apparatus M in which the front door11is opened, the tray171is positioned outside the image forming apparatus main assembly170, and the process cartridges100are removed from the tray. Part (a) ofFIG.7is a partial detailed view of the tray171as viewed from the drive-side in the state shown inFIG.4. Part (b) ofFIG.7is a partial detailed view of the tray171as viewed from the non-drive-side in the state ofFIG.4.

As shown inFIGS.4and5, the tray171is movable relative to the image forming apparatus main assembly170in an arrow X1direction (pushing-in direction) and an arrow X2direction (pulling-out direction). That is, the tray171is provided so as to be able to be pulled out of and pushed into the image forming apparatus main assembly170, and the tray171is structured to be movable in a substantially horizontal direction in a state in which the image forming apparatus main assembly170is placed on a horizontal plane. Here, the state in which the tray171is positioned outside the image forming apparatus main assembly170(the state inFIG.5) is referred to as an outer position. In addition, a state in which the tray171is positioned inside the main assembly170of the image forming apparatus with the front door11open and the photosensitive drum104and the transfer belt12aare separated from each other (state shown inFIG.4) is referred to as an inner position. Further, the tray171is provided with a mounting portion171ato which the process cartridge100can be dismountably mounted at an outer position as shown inFIG.6. Each process cartridge100mounted on the mounting portion171aoutside the tray171is supported on the tray171by a drive-side cartridge cover member116and a non-drive-side cartridge cover member117as shown inFIG.7. And, the process cartridges100are moved into the inside the image forming apparatus main assembly170as the tray171is moved while being supported in the mounting portions171a. At this time, the tray171moves with the transfer belt12aand the photosensitive drum104with a gap therebetween between, and therefore, the tray171can move the process cartridges100into the main assembly170of the image forming apparatus without the photosensitive drum104coming into contact with the transfer belt12a(details will be described hereinafter).

As described above, the plurality of process cartridges100can be collectively moved by the tray171to the respective positions where image formation is possible inside the image forming apparatus main assembly170, and can be collectively moved to the outside of the image forming apparatus main assembly170. After inserting each process cartridge100(100Y,100M,100C,100K) into the tray171, the connecting member201is connected with the developing unit109of the process cartridge100Y, the developing unit109of the first process cartridge100Y, the developing unit109of the cartridge100M and, and the developing unit109of the process cartridge100C. Details will be described hereinafter.

[Positioning Process Cartridge to Electrophotographic Image Forming Apparatus].

Referring toFIG.7, positioning of the process cartridge100to the image forming apparatus main assembly170will be described in more detail. As shown inFIG.7, the tray171is provided with positioning portions171VR and171VL for holding the process cartridge100, respectively. The positioning portion171VR has linear portions171VR1and171VR2, respectively. The structure is such that arc portions116VR1and116VR2of the drive-side cartridge cover member116shown inFIG.7contact the linear portions171VR1and171VR2to determine the center of the photosensitive drum. In addition, the tray171shown inFIG.7is provided with a rotation determining projection171KR. The attitude of the process cartridge100is determined with respect to the apparatus main assembly170by engaging with the rotation determining recess portion116KR position of the drive-side cartridge cover member116shown inFIG.7. Here, a positioning portion171VL and a rotation determining projection171KL are arranged at positions (non-drive-side) opposite from the positioning portion171VR in the longitudinal direction of the process cartridge100with the transfer belt12ainterposed therebetween. In other words, the position of the process cartridge100is determined on the non-drive-side by engagement between the circular arc portions117VL1and117VL2of the non-drive-side cartridge cover member117and the positioning portion171VL and by engagement between the rotation determining recess portion117KL and the rotation determining projection171KL. By doing so, the position of the process cartridge100is correctly determined with respect to the tray171.

Then, as shown inFIG.5, the process cartridges100integrated with the tray171are moved in the direction of the arrow X1and inserted to the position shown inFIG.4. Then, by closing the front door11in the direction of arrow R, the process cartridge100is pressed by a cartridge pressing mechanism (not shown) which will be described hereinafter, and fixed to the image forming apparatus main assembly170together with the tray171. In addition, the transfer belt12ais contacted by the photosensitive member4in interrelation with the operation of the cartridge pressing mechanism. In this state, an image forming operation is enabled (FIG.2). In this embodiment, the positioning portion171VR and the positioning portion171V are made of metal plate because they also function to reinforce the rigidity of the tray171when the tray171is pulled out, but the present invention is not limited to such an example.

Referring toFIG.8, details of the cartridge pressing mechanism will be described. Part (a) ofFIG.8shows only the process cartridge100, tray171, cartridge pressing mechanisms190and191, and intermediary transfer unit12in the state ofFIG.4. Part (b) ofFIG.8shows only the process cartridge100, tray171, cartridge pressing mechanisms190and191, and intermediary transfer unit12in the state ofFIG.2.

While the process cartridge100receives driving force during image forming operation, it also receives reaction force in the direction of arrow Z1from the primary transfer roller12d(FIG.2). Therefore, it is necessary to press the process cartridges in the Z2direction in order to keep the process cartridges in a stable attitude without floating from the positioning portions171VR and171VL during the image forming operation. In order to achieve these, in this embodiment, the image forming apparatus main assembly170is provided with a cartridge pressing mechanism (190,191).

The cartridge pressing mechanism (190,191) includes a storing element pressing unit190on the non-drive-side and a cartridge pressing unit191on the drive-side. Further details will be described. By closing the front door11shown inFIG.4, the storing element pressing unit190and the cartridge pressing unit191shown inFIG.8are lowered in the direction of arrow Z2. The storing element pressing unit190has main assembly side electrical contacts (not shown) which are to be contacted by electrical contacts of memory elements (not shown) provided in the process cartridge100. By interlocking with the front door11by a link mechanism (not shown), the storing element140and the main assembly side electrical contact can be brought into contact with each other and can be brought out of contact from each other. More particularly, when the front door11is closed, the contacts are brought into contact with each other, and when the front door11is opened, they are brought out of contact from each other. By doing so, when the process cartridges100move into the main assembly of the image forming apparatus together with the tray171, the electrical contacts are not rubbed, and the inserting and pulling-out operations of the tray171is not hindered because the electrical contacts are retracted from the insertion/pulling-out paths the process cartridges100.

The storing element pressing unit190also functions to press the process cartridge100against the positioning portion171VR. Similarly, to the storing element pressing unit190, the cartridge pressing unit121also lowers in the direction of the arrow Z2in interrelation with the closing operation of the front door11, and has the function of pressing the process cartridge100against the positioning portion171VL. In addition, although the details will be described hereinafter, the cartridge pressing mechanisms (190,191) further functions to press down force applying members152L,152R of the process cartridges100Y,100K, which will be described hereinafter.

Referring toFIGS.9and10(the tray171omitted for convenience of illustration), the drive transmission mechanism of the main assembly in this embodiment will be described. Part (a) ofFIG.9is a perspective view of the image forming apparatus in the state shown inFIG.4or5, with the process cartridge100and tray171omitted. Part (b) ofFIG.9is a perspective view of the image forming apparatus state shown inFIG.1with the process cartridge100, the front door11and the tray171omitted.FIG.10is a side view of the process cartridge100Y as viewed from the drive-side. Since the drive transmission mechanisms for rotationally driving the photosensitive drums104and the developing rollers106are common among the first to fourth process cartridges, only the process cartridge100Y will be described as a representative.

As shown inFIG.10, the process cartridge100of this embodiment has a development coupling portion32aand a drum coupling member (photosensitive member coupling member)143. By closing the front door11(the state shown in part (b) ofFIG.9, the main assembly side drum drive coupling180and the main assembly side development drive coupling185which transmit drive to the process cartridge100are moved in the direction of the arrow Y1by a link mechanism (not shown). In addition, by opening the front door11(state shown in part (a) ofFIG.9, the drum drive coupling180and the development drive coupling185are retracted in the arrow Y2direction. By retracting each coupling from the insertion/removal trace (X1direction, X2direction) of the process cartridge, the insertion/removal operations of the tray171are not hindered. By closing the front door11and starting to operate the image forming apparatus main assembly170, the drum drive coupling180is engaged with the drum coupling member143, and the main assembly side development drive coupling185is engaged with the development coupling portion32a, and the drive is transmitted to the process cartridge100. The drive transmission to the process cartridge100is not limited to the two locations as described above, and the mechanism may be such that the drive is transmitted only to the drum coupling, and the drive is transmitted also to the developing roller106.

[Structure of Intermediary Transfer Unit]

Referring toFIG.9, the intermediary transfer unit12of the image forming apparatus main assembly170in this embodiment will be described. In this embodiment, when the front door11is closed, the intermediary transfer unit12is lifted in the direction of the arrow R2by a linkage mechanism (not shown) to a position to be taken during the image forming operation (a position where the photosensitive drum104and the transfer belt12aare in contact with each other).

In addition, by opening the front door11, the intermediary transfer unit12descends in the direction of the arrow R1, thus separating the photosensitive drum104and the transfer belt12afrom each other. That is, in a state in which the process cartridge100is set on the tray171, the photosensitive drums104and the transfer belt12acontact and separate from each other according to the opening/closing operation of the front door11. In the contact separation operation, the intermediary transfer unit12moves up and down while drawing a rotation locus centered on the center point PV1shown inFIG.4. Thus, the transfer belt12ais rotated by receiving the force from a gear (not shown) provided coaxially with the PVI. Therefore, the intermediary transfer unit12can moves up and down without moving the gear center by setting the above-mentioned position PV1as the rotation center. This eliminates the need to move the center of the gear, thus making it possible to maintain the position of the gear with high accuracy.

With the above-described structure, when the tray11is inserted or removed with the process cartridge100set on the tray171, the photosensitive drum104and the transfer belt12ado not slide relative to each other, thereby preventing image deterioration attributable to scratch of the photosensitive drum104or charge memory.

Referring toFIGS.8,11and12, a separation mechanism of the main assembly of the image forming apparatus in this embodiment will be described.FIG.11is a cross-sectional view of the image forming apparatus main assembly170taken along the drive-side end portion of the process cartridge100.FIG.12is a perspective view of the development separation control unit195as viewed obliquely from the top.

In this embodiment, the development separation control unit195controls the separation and contact operation of the development units109Y and109K with respect to the photosensitive drum104by engaging with a portion of the development units109Y and109K. In this embodiment, the development separation control unit195engages only with the developing units of the process cartridges100Y and100K, and does not engage with the developing units of the process cartridges100M and100C. However, since the developing units109M and109C operate in interrelation with the operation of the developing unit109Y by the connecting member which will be described hereinafter, the development separation control unit195indirectly controls the separating and contacting operations of the process cartridges100M and100C. The development separation control unit195is positioned in a lower part of the image forming apparatus main assembly170as shown inFIG.8.

Specifically, the development separation control unit195is arranged vertically below the development coupling portion32aand the drum coupling member143(downward in the arrow Z2direction). In addition, the development separation control unit195is arranged in the longitudinal direction (Y1, Y2direction) of the photosensitive drum104of the intermediary transfer unit12. That is, the development separation control unit195includes a development separation control unit195R on the drive-side and a development separation control unit195L on the non-drive-side. As described above, by arranging the development separation control unit195in the dead space of the image forming apparatus main assembly170, the main assembly can be downsized.

The development separation control unit195R has at least two separation control members196R corresponding to the process cartridges100(100Y,100K). The separation control members have substantially the same shape. The development separation control unit195R is always fixed with respect to the image forming apparatus main assembly170. However, the separation control member196R is structured to be movable in the W41and W42directions by a control mechanism (not shown), and among the separation control members196R, the separation control members corresponding to the process cartridges100Y,100M, and100C operate synchronously. A detailed structure will be described hereinafter. In this embodiment, the image forming apparatus main assembly170has four development separating members196R corresponding to the process cartridges100Y,100M,100C and100K.

The development separation control unit195L has at least two separation control members196L corresponding to the process cartridges100(100Y,100K). The separation control members have substantially the same shape. The development separation control unit195L is always fixed to the image forming apparatus main assembly170. However, the separation control member196L is structured to be movable in directions W41and W42by a control mechanism (not shown), and among the separation control members196R, the separation control members corresponding to the process cartridges100Y,100M, and100C operate synchronously. In this embodiment, the image forming apparatus main assembly170has four development separating members196L corresponding to the process cartridges100Y,100M,100C, and100K.

Further, in order for the development separation control unit195to engage with a portion of the developing unit109to control the separation and contact operation of the developing unit109, a part of the development control unit196and a part of the developing unit109need to overlap in the vertical direction (Z1, Z2directions). Therefore, in order to accomplish the above-described overlapping in the vertical direction (Z1, Z2direction) after the developing units109of the process cartridges100Y and100K are inserted in the X1direction, a part of the developing units109(in this embodiment) needs to be projected (details will be described hereinafter). If the development separation control unit195itself is lifted in the same manner as with the intermediary transfer unit12fto effect the engagement, problems such as an increase in the operating force of the interlocking front door11and complication of the drive train arise.

In this embodiment, a method is employed in which the development separation control unit195is fixed to the image forming apparatus main assembly170, and a part of the developing unit109(the force applying member152) is projected downward (Z2) in the image forming apparatus main assembly170, and this is done in view of the problems. In addition, the mechanism for projecting the force applying member152uses the mechanisms of the storing element pressing unit190and the cartridge pressing unit191as they are, the problems described above do not occur and the cost of the main assembly of the apparatus can be suppressed. Although the development separation control unit195as a whole is fixed to the image forming apparatus main assembly170a part thereof is structured to be movable, as will be described hereinafter, for the motion to accomplish the separated and contacted states of the developing unit109relative to the photosensitive drum104through engagement with the force applying member152. Details will be described hereinafter.

[Overall Structure of Process Cartridge]

Referring toFIGS.3,13and14, the structure of the process cartridge will be described. In each Figure, part (a) shows the process cartridges100Y and100K including the separation and contact mechanism150, and part (b) shows the process cartridges100M and100C which do not include the separation and contact mechanism150.FIG.13is an assembly perspective view of the process cartridge100Y as viewed from the drive-side, which is one end side of the photosensitive drum104in the axial direction.FIG.14is a perspective view of the process cartridge100Y as viewed from the drive-side.

In this embodiment, the process cartridges100(100Y,100M,100C, and100K) have the same electrophotographic process mechanism, and differ from each other in the color and amount of toner contained therein. However, as described above, the process cartridges100Y and100K have the separation and contact mechanism150, and the process cartridges100C and100K do not have the separation and contact mechanism150.

The process cartridge100comprises photosensitive drums104(104Y,104M,104C,104K) and process means actable on the photosensitive drums104. Here, the process means includes a charging roller105as charging means for charging the photosensitive drum104, a developing roller106as developing means (developing member) for developing a latent image formed on the photosensitive drum104, and a cleaning blade as a cleaning means for removing residual toner remaining on the surface of the photosensitive drum104, or the like. However, the cleaning means may not be necessary in some cases, and it is assumed that there is no cleaning means in this embodiment. The process cartridge100is divided into drum units108(108Y,108M,108C,108K) and developing units109(109Y,109M,109C,109K). As has been described above, the image forming apparatus of the present disclosure includes the process cartridges100Y and100K including the separation and contact mechanism150and the process cartridges100M and100C not including the separation and contact mechanism150. However, the substantial structure other than the presence or absence of the separation and contact mechanism is the same.

As shown inFIGS.3and13, the drum unit108includes the photosensitive drum104, the charging roller105, and the drum frame115as a first frame. The photosensitive drum104is rotatably supported by a drive-side cartridge cover member116and a non-drive-side cartridge cover member117provided at opposite longitudinal ends of the process cartridge100. The drive-side cartridge cover member116and the non-drive-side cartridge cover member117will be described hereinafter.

As shown inFIGS.13and14, a drum coupling member143for transmitting driving force to the photosensitive drum104is provided at one end of the photosensitive drum104in the longitudinal direction. As described above, the drum coupling member143engages with the main assembly side drum drive coupling180(seeFIG.9) as a drum drive output portion of the image forming apparatus main assembly170to drive the image forming apparatus main assembly170, so that the driving force of a motor (not shown) is transmitted to the photosensitive drum104to rotate it in the arrow A direction. In addition, the photosensitive drum104has a drum flange142on the other longitudinal end side. The charging roller105is supported by the drum frame115so as to be in contact with the photosensitive drum104and to be rotationally driven.

[Structure of Developing Unit]

As shown inFIGS.3and13, the developing unit109includes a developing roller106, a toner feeding roller107, a developing blade130, a developing unit frame125as a second frame, and the like. The developing unit frame125comprises a lower frame125aand a lid member125b. The lower frame125aand the lid member125bare joined by ultrasonic welding or the like. A developing unit frame125, which is a second frame, has a toner containing portion129containing toner to be supplied to the developing roller106. The developing unit frame125rotatably supports the developing roller106and the toner feeding roller107by way of a drive-side bearing126and a non-drive-side bearing127, which will be described hereinafter, and supports a developing blade130for regulating a thickness of the toner on the periphery of the developing roller106.

The developing blade130is provided by mounting an elastic member130b, of a metal plate having a thickness of about 0.1 mm on a support member130aof metal material having an L-shaped cross-section, by welding or the like. The developing blade130is mounted to the developing unit frame125with fixing screws130cat two locations, namely, one end and the other end in the longitudinal direction. The developing roller106comprises a metal core106cand a rubber portion106d.

The developing roller106is rotatably supported by a drive-side bearing126and a non-drive-side bearing127mounted to opposite longitudinal ends of the developing unit frame125. As shown inFIGS.13and14, a development coupling portion32afor transmitting driving force to the developing unit109is provided at one end of the developing unit109in the longitudinal direction. The development coupling portion32aengages with a main assembly side development drive coupling185(seeFIG.9) as a development drive output portion of the image forming apparatus main assembly170, and the drive of a drive motor (not shown) of the image forming apparatus main assembly170is inputted to the developer unit109. The driving force inputted to the developing unit109is transmitted by a drive train (not shown) provided in the developing unit109, so that the developing roller106can be rotated in the direction of arrow D inFIG.3. At one end in the longitudinal direction of the developing unit109, a development cover member128for supporting and covering the development coupling portion32aand a drive train (not shown) is provided. Here, the outer diameter of the developing roller106is smaller than the outer diameter of the photosensitive drum104. The outer diameter of the photosensitive drum104in this embodiment is within a range of Φ18 to Φ22, and the outer diameter of the developing roller106is within a range of Φ8 to Φ14. Efficient arrangement is possible by using these outer diameters.

[Assembling Drum Unit and Developing Unit]

Referring toFIG.13, assembly of the drum unit108and the developing unit109will be described. The drum unit108and the developing unit109are connected by a drive-side cartridge cover member116and a non-drive-side cartridge cover member117provided at opposite longitudinal ends of the process cartridge100. A drive-side cartridge cover member116provided at one end in the longitudinal direction of the process cartridge100is provided with a developing unit support hole116afor swingably (movably) supporting the developing unit109. Similarly, a non-drive-side cartridge cover member117provided at the other longitudinal end of the process cartridge100is provided with a developing unit support hole117afor swingably supporting the developing unit109. In addition, the drive-side cartridge cover member116and the non-drive-side cartridge cover member117are provided with drum support holes116band117bfor rotatably supporting the photosensitive drum104.

Here, the outer diameter portion of the cylindrical portion128bof the development cover member128is fitted into the development unit support hole116aof the drive-side cartridge cover member116at the one end side. On the other end side, the outer diameter portion of the cylindrical portion (not shown) of the non-drive-side bearing127is fitted into the developing unit support hole117aof the non-drive-side cartridge cover member117. Further, the opposite ends of the photosensitive drum104in the longitudinal direction are fitted into the drum supporting holes116bof the drive-side cartridge cover member116and the drum supporting holes117bof the non-drive-side cartridge cover member117, respectively. The drive-side cartridge cover member116and the non-drive-side cartridge cover member117are fixed to the drum unit108by screws, adhesive, or the like (not shown). By this, the developing unit109is supported by the drive-side cartridge cover member116and the non-drive-side cartridge cover member117so as to be rotatable with respect to the drum unit108(photosensitive drum104), and can be positioned suitably for acting on the photosensitive drum104during the image forming operation.

FIG.14shows a state in which the drum unit108and the developing unit109are assembled through the above steps and integrally formed as the process cartridge100. An axis connecting the center of the developing unit support hole116aof the drive-side cartridge cover member116and the center of the developing unit support hole117aof the non-drive-side cartridge cover member117is called a swing axis K. Here, the cylindrical portion128bof the development cover member128on the one end side is coaxial with the development coupling32. That is, the developing unit109is structured such that the driving force is transmitted from the image forming apparatus main assembly170at this swing axis K. Further, the developing unit109is supported rotatably about the swing axis K.

[Structure of Separation and Contact Mechanism]

As described above, the process cartridges100Y and100K includes the separation and contact mechanism150. Here, a detailed description will be made as to a structure in which the photosensitive drums104of the process cartridges100Y and100K in this embodiment and the developing rollers106of the developing units109are separated from each other and contacted with each other. The process cartridges100Y and100K include a drive-side separation and contact mechanism150R on the drive-side and a non-drive-side separation and contact mechanism150L on the non-drive-side.

FIG.15shows an assembly perspective view of the drive-side of the developing unit109including the drive-side separation and contact mechanism150R.FIG.16shows an assembly perspective view of the non-drive-side of the developing unit109including the non-drive-side separation and contact mechanism150L. Regarding the separation and contact mechanism150, the drive-side separation and contact mechanism150R will first be described in detail, and then the non-drive-side separation and contact mechanism150L will be described. As for the separation and contact mechanism, the drive-side and the non-drive-side have almost the same function, and therefore, R is indicated at the end of the reference numeral of each member for the drive-side. For the non-drive-side, the reference numerals of the respective members are the same as those on the drive-side, and L is added at the end.

The separation and contact mechanism150R has a separation holding member151R as a regulating member, a force applying member152R as a pressing member, and a tension spring153. The non-drive-side separation and contact mechanism150L has a separation holding member151L as a regulating member, a force applying member152L as a pressing member, and a tension spring153.

[Detailed Description of Separation Holding Member151R]

Referring to Figure, the separation holding member151R will be described in detail. Part (a) ofFIG.17is a front view of the separation holding member151R per se as viewed in the longitudinal direction of the process cartridge100from the drive-side, part (b) ofFIG.17and part (c) ofFIG.17are perspective views of the separation holding member151R, and part (d) ofFIG.17is a view of the separation holding member151R as viewed in the direction of arrow Z2in part (a) ofFIG.17(vertical upward direction in the image forming state). The separation holding member151R has an annular support receiving portion151Ra, and has a separation holding portion151Rb projecting from the support receiving portion151Ra in the radial direction of the support receiving portion151Ra. The free end of the separation holding portion151Rb has a separation holding surface151Rc including an arcuate shape centered on the separation holding swing axis H and inclined at an angle θ1 with respect to a line HA parallel to the separation holding swing axis H. The angle θ1 is set so as to satisfy Expression (1).

Further, the separation holding member151R has a second restricted surface151Rk adjacent to the separation holding surface151Rc. Further, the separation holding member151R has a second pressed portion151Rd which projects in the Z2direction from the support receiving portion151Ra, and an arc shaped second pressed surface151Re which projects from the second pressed portion151Rd in the direction of the separation holding swing axis H of the support receiving portion151Ra. Furthermore, the separation holding member151R includes a main body portion151Rf connected to the support receiving portion151Ra, and the main body portion151Rf has a spring hooked portion151Rg projecting in the separation holding swing axis H direction of the support receiving portion151Ra. Moreover, the main body portion151Rf has a rotation preventing portion151Rm which projects in the Z2direction, and a rotation preventing surface151Rn is provided in a direction facing the second pressed surface151Re.

[Detailed Description of Force Applying Member R]

Referring toFIG.18, the force applying member152R will be described in detail. Part (a) ofFIG.18is a front view of the force applying member152R per se as viewed in the longitudinal direction of the process cartridge100, and part (b) ofFIG.18and part (c) ofFIG.18are perspective views of the force applying member152R per se. The force applying member152R has an oblong support receiving portion152Ra. Here, the longitudinal direction of the oblong shape of the oblong support receiving portion152Ra is indicated by arrow LH, the upward direction is indicated by arrow LH1, and the downward direction is indicated by arrow LH2. In addition, the direction of the depth of the oblong support receiving portion152Ra is HB.

The force applying member152R is provided with a projecting portion152Rh formed on the downstream side of the oblong support receiving portion152Ra in the direction of the arrow LH2. The oblong support receiving portion152Ra and the projecting portion152Rh are connected by a main body portion152Rb. On the other hand, the force applying member152R has a pushed portion152Re which projects in the direction of the arrow LH1and in a direction substantially perpendicular to the direction of the arrow LH1, and is provided with an arc shaped pushed surface152Rf on the downstream side thereof in the arrow LH1direction and is provided with a push-restricting surface152Rg on the upstream side. In addition, the force applying member152R is provided with a first at-retraction restricting surface152Rv extending from the body portion152Rb toward an upstream side in the direction of the arrow LH2from the projecting portion152, and a second at-retraction restricting surface152Rw extending substantially in parallel with a first pressing surface152Rq adjacent to the first at-retraction restricting surface152Rv.

The projecting portion152Rh is provided with a first force receiving portion152Rk and a second force receiving portion152Rn which are arranged to face each other in a direction approximately perpendicular to the direction of the arrow LH2at the end portion of the direction of the arrow LH2. The first force receiving portion152Rk and the second force receiving portion152Rn have a first force receiving surface152Rm and a second force receiving surface152Rp extending in the HB direction and having an arc shape, respectively. The projecting portion152Rh has a spring hooked portion152Rs and a locking portion152Rt projecting in the HL direction, and the locking portion152Rt has a locking surface152Ru facing in the same direction as the first force receiving surface152Rp.

Further, the force applying member152R is provided with a first pressing surface152Rq which is a part of the main body portion152Rb and arranged upstream, in the direction of the arrow LH2, of the second force receiving portion152Rn and which faces in the same direction as the second force receiving surface152Rp. In addition, the force applying member152R has a second pressing surface152Rr which is perpendicular to the first retraction restricting surface152Rv and is opposed to the first pressing surface152Rq. When the process cartridge100is mounted in the image forming apparatus main assembly170, the LH1direction is substantially the same as the Z1direction, and the LH2direction is substantially the same direction as the Z2direction. Also, the HB direction is substantially the same as the longitudinal direction of the process cartridge100.

[Assembly of Separation and Contact Mechanism R]

Referring toFIGS.10and15to19, assembly of the separation and contact mechanism will be described.FIG.19is a perspective view of the process cartridge100after the separation holding member151R is assembled, as viewed from the drive-side. As described above, as shown inFIG.15, the developing unit109is rotatably supported with respect to the photosensitive drum104about the axis K by fitting the outer diameter portion of the cylindrical portion128bof the development cover member128into the developing unit support hole116aof the drive-side cartridge cover member116. In addition, the development cover member128has a first cylindrical support portion128cand a second support portion128kwhich project in the direction of the swing axis K.

The outer diameter of the first support portion128cfits to the inner diameter of the support receiving portion151Ra of the separation holding member151R to rotatably support the separation holding member151R. Here, the swing center of the separation holding member151R assembled to the development cover member128is referred to as the separation holding swing axis H. The development cover member128has a first retaining portion128dwhich projects in the direction of the separation holding swing axis H. As shown in Figure As shown inFIG.15, the movement of the separation holding member151R assembled to the development cover member128in the separation holding swing axis H direction is restricted by the contact of the separation holding member151R with the first retaining portion128d.

In addition, the outer diameter of the second support portion128kis fitted to the inner wall of the oblong support receiving portion152Ra of the force applying member152R to support the force applying member152R rotatably and movably in the oblong direction. Here, the swing center of the force applying member152R assembled to the development cover member128is defined as a force applying member swing axis HC. As shown inFIG.15, the movement of the force applying member152R assembled to the development cover member128in the direction of the force applying member swing axis HC is restricted by the contact of the second retaining portion128mwith the separation holding member151R.

FIG.10is a cross-sectional view in which a part of the drive-side cartridge cover member116and a part of the development cover member128are partly omitted along a partial cross-sectional line CS so that the fitting portion between the oblong support receiving portion151Ra of the force applying member152R and the cylindrical portion128bof the development cover member128can be seen. The separation and contact mechanism150R is provided with a tension spring153as an urging means for urging the separation holding member151R to rotate in the arrow B1direction in the drawing about the separation holding swing axis H and urging the force applying member152R in the arrow B3direction. The arrow B3direction is substantially parallel to the longitudinal direction LH2direction (seeFIG.18) of the oblong support receiving portion152Ra of the force applying member152R. The tension spring153is provided between a spring hooked portion151Rg provided on the separation holding member151R and a spring hooked portion152Rs provided on the force applying member152R. The tension spring153applies force to the spring hooked portion151Rg of the separation holding member151R in the direction of arrow F2inFIG.10, thereby applying an urging force to rotate the separation holding member151R in the direction of arrow B1. In addition, the tension spring153applies a force to the spring hooked portion152Rs of the force applying member152R in the arrow F1direction, thereby applying an urging force to move the force applying member152R in the arrow B3direction.

An angle θ2 formed between a line GS connecting the spring hooked portion151Rg of the separation holding member151R and the spring hooked portion152Rs of the force applying member152R, and a line HS connecting the spring hooked portion152Rs of the force applying member152R and the swing axis HC of the force applying member, and is selected so as to satisfy the following formula (2), with the clockwise direction around the spring hooked portion152Rs of the force applying member152R being positive. By this, the force applying member152R is urged to rotate in the arrow BA direction about the force applying member swing axis HC.

As shown inFIG.15, the development drive input gear132is arranged such that the inner diameter of the cylindrical portion128bof the development cover member128and the outer diameter of the cylindrical portion32bof the development drive input gear132are fitted, and the portion126aof the drive-side bearing126is fitted in a cylindrical portion (not shown) of the development driving input gear, by which, the driving force is transmitted to the developing roller gear131, the toner feeding roller gear133, and other gears.

In this embodiment, the mounting positions of the separation holding member151R and the force applying member152R is such that in the direction of the swing axis K, the separation holding member151R is provided (outside in the longitudinal direction) the side on which the drive-side cartridge cover member116exists, with respect to the development cover member128, and the force applying member152R is disposed on the side (inner side in the longitudinal direction) on which the development drive input gear132exists, with respect to the development cover member128. However, the such positions is not limiting, and the arrangement positions of the separation holding member151R and the force applying member152R may be exchanged, and the separation holding member151R and the force applying member152R may be provided on one side of the development cover member128in the swing axis K direction with as a reference. Further, the arrangement order of the separation holding member151R and the force applying member152R may be changed.

The development cover member128is fixed to the developing unit frame125by way of the drive-side bearing126to form the developing unit109. Although the fixing method in this embodiment uses a fixing screw145and an adhesive (not shown) as shown inFIG.15, the fixing method is not limited to such an example, and heat welding or resin material may be used.

Here,FIG.20is a cross-sectional view in which the neighborhood of the separation holding member151R inFIG.10is enlarged, and a part of the tension spring153and the separation holding member151R is partially omitted along a sectional line CS4, for better illustration. In the force applying member152R, the force applying force of the tension spring153directed in the F1direction in the drawing causes the first retracted restricting surface152Rv of the force applying member152R to come into contact with the first restricting surface128hof the development cover member128. In addition, the second at-retraction restricting surface152Rw of the force applying member152R contacts the second restricting surface128qof the development cover member128to be positioned in place. This position is referred to as a retracted position (reference position) of the force applying member152R. Further, the separation holding member151R is rotated in the B1direction about the separation holding swing axis H by the urging force of the tension spring153in the F2direction, so that the second pressed portion151Rd of the separation holding member151R comes into contact with the second pressing surface152Rr of the force applying member152R, by which the rotation thereof is stopped. This position is referred to as the separation holding position (restriction position) of the separation holding member151R.

Furthermore,FIG.21is an enlarged view of the separation holding member151R and the peripherals thereof inFIG.10, with the tension spring153omitted, for better illustration. It is assumed here that the process cartridge100including the separation and contact mechanism150R described in this embodiment drops off in the direction of JA inFIG.21during transportation. At this time, the separation holding member151R receives a rotational force in the arrow B2direction about the separation holding swing axis H due to its own weight. When the separation holding member151R begins to rotate in the direction B2for the reason described above, the rotation preventing surface151Rn of the separation holding member151R abuts against the locking surface152Ru of the force applying member152R, and the separation holding member151R receives the force in the F3direction in the drawing so as to suppress rotation in the B2direction. By this, the rotation of the separation holding member151R in the B2direction during distribution can be suppressed, and the separation state between the photosensitive drum104and the developing unit109can be prevented from being impaired.

In this embodiment, the tension spring153is used as the urging means for urging the separation holding member151R to the separation holding position and for urging the force applying member152R to the retracted position, but the urging means is not limited to such an example. For example, a torsion coil spring, a leaf spring, or the like may be used as urging means to urge the force applying member152R to the retracted position and the separation holding member151R to the separation holding position. Further, the material of the urging means may be metal, mold, or the like, as long as it has elasticity and can urge the separation holding member151R and the force applying member152R. As described above, the developing unit109provided with the separation and contact mechanism150R is integrally coupled with the drum unit108by the drive-side cartridge cover member116as described above (state ofFIG.19).

FIG.22is an illustration as viewed in the direction of arrow J inFIG.19. As shown inFIG.15, the drive-side cartridge cover member116of this embodiment has a contact surface116c. The contact surface116cis formed with an inclination angle θ3 with respect to the swing axis K, as shown inFIG.22. The angle θ3 is preferably the same as the angle θ1 forming the separation holding surface151Rc of the separation holding member151R, but the angle θ3 is not limited to such an angle. Further, as shown inFIGS.15and19when the drive-side cartridge cover member116is assembled to the developing unit109and the drum unit108, the contact surface116cfaces the separation holding surface151Rc of the separation holding member151R placed at the separation holding position and contacts the separation holding surface151Rc by the urging force of the development pressure spring134, which will be described hereinafter. The structure is such that when the engagement surface116Rc and the separation holding surface151Rc are brought into contact with each other, the developing unit109is positioned so that the developing roller106of the developing unit109and the photosensitive drum104are spaced by a gap P1. Thus, the state in which the developing roller106(developing member) is spaced from the photosensitive drum104by the gap P1by the separation holding member151R is referred to as a separated position (retracted position) of the developing unit109(see part (a) ofFIG.34.

Here, referring toFIGS.24and25, the separation state and contact state of the process cartridge100will be described in detail.FIGS.24and25are side views of the process cartridge100mounted inside the image forming apparatus main assembly170as viewed from the drive-side.FIG.24shows a state in which the developing unit109is separated from the photosensitive drum104.FIG.25shows a state in which the developing unit109is in contact with the photosensitive drum104.

First, in a state in which the separation holding member151R is positioned at the separation holding position and the developing unit109is positioned at the separation position, the pushed portion152Re of the force applying member152R is pushed in the ZA direction, so that the projected portion152Rh of the force applying member152R projects from the process cartridge100. The second pressed surface151Re of the separation holding member151R is in contact with the second pressing surface152Rr of the force applying member152R by the tension spring153as described above. Therefore, when the second force receiving portion152Rn is pressed in the direction of arrow W42, the force applying member152R rotates in the direction of arrow BB about the force applying member swing axis HC to rotate the separation holding member151R in the direction of arrow B2. When the separation holding member151R rotates in the arrow B2direction, the separation holding surface151Rc is separated from the contact surface116c, and the developing unit109can rotate in the arrow V2direction about the pivot axis K from the separation position. That is, the developing unit109rotates in the V2direction from the separated position, so that the developing roller106of the developing unit109comes into contact with the photosensitive drum104. Here, the position of the developing unit109in which the developing roller106and the photosensitive drum104contact with each other is referred to as a contact position (developing position) (state shown inFIG.25). The position in which the separation holding surface151Rc of the separation holding member151R separates from the contact surface116cis referred to as a separation release position (allowing position). When the developing unit109is positioned at the contact position, the second restricted surface151Rk of the separation holding member151R comes into contact with the second restricting surface116dof the drive-side cartridge cover member116, thereby maintaining the separation holding member151R in the separation release position.

In addition, the drive-side bearing126is provided with a first pressed surface126cwhich is a surface perpendicular to the swing axis K. Since the drive-side bearing126is fixed to the developing unit109, when the developing unit109is in the contact position and the first force receiving portion152Rk of the force applying member152R is pressed in the direction of the arrow41, by the first pressing surface152Rq contacting the first pressed surface126c, the developing unit109rotates in the direction of the arrow V1about the swing axis K and moves to the separated position (state shown inFIG.24). Here, the direction in which the first pressed surface126cmoves when the developing unit109moves from the contact position to the separated position is indicated by an arrow W41inFIGS.24and25. The direction opposite to the arrow W41is the arrow W42, and the arrows W41and W42are substantially horizontal directions (X1and X2directions). As described above, the second force receiving surface152Rp of the force applying member152R assembled to the developing unit109is positioned upstream of the first pressed surface126cof the drive-side bearing126in the direction of the arrow W41. Further, the first pressed surface126cand the second force receiving surface151Re of the separation holding member151R are arranged at positions where at least parts thereof overlap in the W1and W2directions. The operation of the separation and contact mechanism150R inside the image forming apparatus main assembly170will be described in detail below.

[Mounting of Process Cartridge to Image Forming Apparatus]

Referring toFIGS.12,23and24, the description will be made as to an engaging operation of the separation and contact mechanism150R of the process cartridge100with the development separation control unit195of the image forming apparatus main assembly170when the process cartridge100is mounted into the image forming apparatus main assembly170. For better illustration, these Figures are cross-sectional views in which a part of the development cover member128and a part of the drive-side cartridge cover member116are omitted along cross-sectional lines CS1and CS2.

FIG.23shows the process cartridge100as viewed from the drive-side with omission other than the process cartridge100, the cartridge pressing unit121and the separation control member196R, at the time when the process cartridge100is mounted on the cartridge tray171(not shown) of the image forming apparatus M and the cartridge tray171is inserted into the first mounting position.

As described above, the image forming apparatus main assembly170of this embodiment has the separation control member196R corresponding to each process cartridge100as described above. The separation control member196R is arranged closer to the lower surface side of the image forming apparatus main assembly170than the separation holding member151R when the process cartridge100is positioned at the first inner position and the second inner position. The separation control member196R includes a first force applying surface196Ra and a second force applying surface196Rb which face each other with a space196Rd therebetween and which project toward the process cartridge100. The first force applying surface196Ra and the second force applying surface196Rb are connected by way of a connecting portion196Rc on the lower side of the image forming apparatus main assembly170. In addition, the separation control member196R is rotatably supported by the control metal plate197around a rotation center196Re. The separation control member196R is always urged in the E1direction by an urging spring. Further, the separation control member196R is structured to be movable in the W41and W42directions by structuring the control metal plate197to be movable in the W41and W42directions by a control mechanism (not shown).

In interrelation with the transition of the front door11of the image forming apparatus main assembly170from the open state to the closed state as described above, the cartridge pressing unit121lowers in the direction of the arrow ZA, and the first force application portion121aabuts against the pushed surface152Rf of the force applying member152R. Thereafter, when the cartridge pressing unit121is lowered to a predetermined position, which is the second mounting position, the projecting portion152Rh of the force applying member152R projects downward in the Z2direction of the process cartridge100(state shown inFIG.24). This position is referred to as a projecting position of the force applying member152R. When this operation is completed, a gap T4is formed between the first force applying surface196Ra of the separation control member196R and the first force receiving surface152Rp of the force applying member152R, and a gap T3is formed between the second force applying surface196Rb the second force receiving surface152Rp, as shown inFIG.24. And, it is positioned at the second mounting position where the force applying member152R does not act on the separation control member196R.

This position of the separation control member196R is referred to as a home position. At this time, the first force receiving surface152Rp of the force applying member152R and the first force applying surface196Ra of the separation control member196R are arranged so as to partially overlap with each other in the W1and W2directions. Similarly, the second force receiving surface152Rp of the force applying member152R and the second force applying surface196Rb of the separation control member196R are arranged so as to partially overlap with each other in the W1and W2directions.

[Abutment Operation of Developing Unit]

FIGS.24to26, the operation of bringing the photosensitive drum104and the developing roller106into contact with each other by the separation and contact mechanism150R will be described in detail. These Figures are cross-sectional views in which, for the sake of better illustration, a part of the development cover member128, a part of the drive-side cartridge cover member116, and a part of the drive-side bearing126are omitted, for better illustration, along partial cross-sectional lines CS1, CS2, and CS3.

In this embodiment, the development input coupling32receives a driving force from the image forming apparatus main assembly170in the direction of arrow V2inFIG.24, and the developing roller106rotates. That is, the developing unit109having the development input coupling32receives a torque about the swing axis K in the direction of the arrow V2from the image forming apparatus main assembly170. As shown inFIG.24, when the developing unit109is in the separated position and the separation holding member151R is in the separation holding position, even if the developing unit109receives this torque and the urging force of the developing pressure spring134, which will be described hereinafter, the separation holding surface151Rc of the separation holding member151R contacts the contact surface116cof the drive-side cartridge cover member116, so that the attitude of the developing unit109is maintained at the separation position.

The separation control member196R of this embodiment is structured to be movable from the home position in the direction of arrow W42inFIG.24. When the separation control member196R moves in the W42direction, the second force applying surface196Rb of the separation control member196R and the second force receiving surface152Rp of the force applying member152R are brought into contact with each other, so that the force applying member152R rotates about the force applying member swing axis HC in the direction of arrow BB. Further, as the force applying member152R rotates, the second pressing surface152Rr of the force applying member152R rotates the separation holding member151R in the B2direction in contact with the second pressed surface151Re of the separation holding member151R. Then, the separation holding member151R is rotated by the force applying member152R to the separation release position where the separation holding surface151Rc and the contact surface116care separated from each other. Here, the position of the separation control member196R that moves the separation holding member151R to the separation release position shown inFIG.25is referred to as the first position.

In this manner, when the separation holding member151R is moved to the separation release position by the separation control member196R, the developing unit109is rotated in the direction V2by the torque received from the image forming apparatus main assembly170and the developing pressure spring134, which will be described hereinafter, so that it moves to the contact position where the roller106and the photosensitive drum104are in contact with each other (state shown inFIG.25). At this time, the separation holding member151R urged in the direction of the arrow B1by the tension spring153is maintained at the separation release position by the contact of the second restricted surface151Rk with the second regulating surface116dof the drive-side cartridge cover member116. Thereafter, the separation control member196R moves in the W41direction and returns to the home position. At this time, the force applying member152R is rotated in the BA direction by the tension spring153, and the first pressing surface152Rq of the force applying member152R and the first pressed surface126cof the drive-side bearing126are brought into contact with each other (state ofFIG.26). By this, the above-described gaps T3and T4are formed again, and it is brought to a position where the separation control member196R does not act on the force applying member152R. The transition from the state ofFIG.25to the state ofFIG.26is performed immediately.

As described above, in the structure of this embodiment, by the movement of the separation control member196R from the home position to the first position, the force applying member152R is rotated so that the separation holding member151R can be moved from the separation holding position to the separation release position. This enables the developing unit109to move from the spaced position to the contact position in which the developing roller106and the photosensitive drum104contact each other. The position of the separation control member196R inFIG.26is the same as that inFIG.24.

[Separating Operation of Developing Unit].

Referring toFIGS.26and27, the operation of moving the developing unit109from the contact position to the separated position by the separation and contact mechanism150R will be described in detail. These Figures are cross-sectional views in which, a part of the development cover member128, a part of the drive-side cartridge cover member116, and a part of the drive-side bearing126are omitted, for better illustration, along the sectional line CS.

The separation control member196R in this embodiment is structured to be movable from the home position in the direction of arrow W41inFIG.26. When the separation control member196R moves in the W41direction, the second force applying surface196Rb and the first force receiving surface152Rm of the force applying member152R come into contact with each other, so that the force applying member152R rotates in the direction of the arrow BB about the force applying member swing axis HC. Then, by the first pressing surface152Rq of the force applying member152R being brought into contact with the first pressed surface126cof the drive-side bearing126, the developing unit109is rotated in the direction of the arrow V1about the swing axis K from the contact position (state inFIG.27). At this time, the pushed surface152Rf of the force applying member152R has an arc shape, and the center of this arc is arranged so as to align with the swing axis K. By this, when the developing unit109moves from the contact position to the separated position, the force applied from the cartridge pressing unit121to the pushed surface152Rf of the force applying member152R is directed in the direction of the swing axis K, and therefore, the operation can be performed without hindering the rotation in the direction of arrow V1. In the separation holding member151R, the second restricted surface151Rk of the separation holding member151R and the second regulating surface116dof the drive-side cartridge cover member116are separated from each other, and the separation holding member151R rotates in the arrow B1direction by the urging force of the tension spring153. By this, the separation holding member151R rotates until the second pressed surface151Re comes into contact with the second pressing surface152Rr of the force applying member152R, and with the contact operation, it shifts to the separation holding position. When the separation control member196R moves the developing unit109from the contact position toward the separation position and the separation holding member151R is positioned at the separation holding position, a gap T5is provided between the separation holding surface151Rc and the contact surface116cas shown inFIG.27. Here, the position shown inFIG.27in which the developing unit109is rotated from the contact position toward the separation position so that the separation holding member151can be moved to the separation holding position is referred to as the second position of the separation control member196R.

Thereafter, when the separation control member196R moves in the direction of arrow W42and returns from the second position to the home position, the developing unit109is rotated in the direction of the arrow V2by the torque received from the image forming apparatus main assembly170and a development pressure spring134, which will be described hereinafter, while maintaining the separation holding member151R at the separation holding position, and the separation holding surface151Rc and the contact surface116care brought into contact with each other. In other words, the developing unit109is maintained at the spaced position by the separation holding member151R, and the developing roller106and the photosensitive drum104are spaced from each other with the gap P1therebetween (the state shown inFIGS.24and34(a)). By this, the above-described gaps T3and T4are provided again, and the separation control member196R is positioned at a position where it does not act on the force applying member152R (state shown inFIG.24). The transition from the state ofFIG.27to the state ofFIG.24is carried out immediately.

As described above, in this embodiment, by the separation control member196R moving from the home position to the second position, the separation holding member151R is moved from the separation release position to the separation holding position. And, by the separation control member196R returning from the second position to the home position, the developing unit109maintains the separation position by the separation holding member151R.

[Detailed Description of the Separation Holding Member151L]

Referring to Figure, the separation holding member151L will be described in detail. Part (a) ofFIG.28is a front view of the separation holding member151L per se as viewed in the longitudinal direction of the process cartridge100on the drive-side, and part (b) ofFIG.28and part (c) ofFIG.28are perspective views of the separation holding member151L per se. The separation holding member151L is provided with an annular support receiving portion151La, and is provided with a separation holding portion151Lb projecting from the support receiving portion151La in the radial direction of the support receiving portion151La. The free end of the separation holding portion151Lb has an arc-shaped separation holding surface151Lc centered on the separation holding swing axis H. In addition, the separation holding member151L has a second restricted surface151Lk adjacent to the separation holding surface151Lc. Further, the separation holding member151L is provided with a second pressed portion151Ld which projects in the Z2direction beyond the support receiving portion151La, and is provided with an arc-shaped second pressed surface151Le which projects from the second pressed portion151Ld in the separation holding swing axis (H) direction of the support receiving portion151La. Further, the separation holding member151L has a main body portion151Lf connected to the support receiving portion151La, and the main body portion151Lf is provided with a spring hooked portion151Lg projecting in the separation holding swing axis (H) direction of the support receiving portion151La. Furthermore, the main body portion151Lf is provided with a rotation prevention portion151mprojecting in the Z2direction, and a rotation preventing surface151Ln thereof is provided in a direction facing the second pressed surface151Le.

[Detailed Description of Force Applying Member L]

Referring toFIG.29, The force applying member152L will be described in detail. Part (a) ofFIG.29is a front view of the force applying member152L per se as viewed in the longitudinal direction of the process cartridge100, and part (b) ofFIG.29and part (c) ofFIG.29are perspective views of the force applying member152L per se. The force applying member152L has an oblong support receiving portion152La. Here, the longitudinal direction of the oblong shape of the support receiving portion152La is indicated by arrow LH, the upward direction is indicated by arrow LH1, and the downward direction is indicated by arrow LH2. In addition, the direction in which the oblong support receiving portion152La is formed is defined as HD. The force applying member152L is provided with a projecting portion152Lh formed downstream of the oblong support receiving portion152La in the direction of the arrow LH2. The oblong support receiving portion152La and the projecting portion152Lh are connected by the main body portion152Lb. On the other hand, the force applying member152L is provided with a pushed portion152Le which projects in the direction of the arrow LH1and in a direction substantially perpendicular to the direction of the arrow LH1and is provided with an arc-shaped pushed surface152Lf on a downstream side in the arrow LH1direction and a pushing restricting surface152Lg. Further, the force applying member152L is provided with a first retraction restricting surface152Lv which is a part of the oblong support receiving portion152La and which is located on the downstream side in the direction of the arrow LH2.

The projecting portion152Lh is provided with a first force receiving portion152Lk and a second force receiving portion152Ln which are provided opposite to each other in a direction approximately perpendicular to the direction of the arrow LH2at a terminal portion in the direction of the arrow LH2. The first force receiving portion152Lk and the second force receiving portion152Ln have a first force receiving surface152Lm having an arc shape and a second force receiving surface152Lp, respectively, the first force receiving surface152Lm and the second force receiving surface152Lp extending in the HD direction. In addition, the projecting portion152Lh is provided with a spring hooked portion152Ls projecting in the HB direction and a locking portion152Lt, and the locking portion152Lt has a locking surface152Lu facing in the same direction as the second force receiving surface152Lp.

Further, the force applying member152L is a part of the main body portion152Lb, is disposed on the upstream side of the second force receiving portion152Ln in the direction of the arrow LH2, and has a first pressing surface152Lq facing in the same direction as the second force receiving surface152Lp. Further, the force applying member152L is provided with a second pressing surface152Lr which is a part of the main body portion152Lb and which faces in the same direction as the first force receiving surface152Lm, the second pressing surface152Lr being disposed on the upstream side of the first force receiving portion152Lk in the direction of the arrow LH2. When the process cartridge100is mounted in the image forming apparatus main assembly170, the LH1direction is substantially the same direction as the Z1direction, and the LH2direction is substantially the same direction as the Z2direction. Also, the HB direction is substantially the same as the longitudinal direction of the process cartridge100.

[Assembly of Separation and Contact Mechanism L]

Referring toFIGS.16and29to35, the assembly of the separating mechanism will be described.FIG.30is a perspective view of the process cartridge100after the separation holding member151L is assembled, as viewed from the drive-side. As described above withFIG.16, the developing unit109is supported rotatably relative to the photosensitive drum104about the driving axis K by fitting the outer diameter portion of the cylindrical portion127aof the non-drive-side bearing127into the developing unit support hole117aof the non-drive-side cartridge cover member117. In addition, the non-drive-side bearing127is provided with a first cylindrical support portion127band a second support portion127ewhich project in the direction of the swing axis K.

The outer diameter of the first support portion127bis fitted to the inner diameter of the support receiving portion151La of the separation holding member151L to rotatably support the separation holding member151L. Here, the swing center of the separation holding member151L assembled to the non-drive-side bearing127is referred to as the separation holding swing axis H. The non-drive-side bearing127has a first retaining portion127cprojecting in the direction of the separation holding swing axis H. As shown inFIG.16, the movement of the separation holding member151L assembled to the non-drive-side bearing127in the direction of the spacing holding swing axis H is restricted by the contact of the first retaining portion127cwith the separation holding member151L.

Further, the outer diameter of the second support portion127eis fitted to the inner wall of the oblong support receiving portion152La of the force applying member152L to support the force applying member152L rotatably and movably in the oblong direction. Here, the swing center of the force applying member152L assembled to the non-drive-side bearing127is referred to as the force applying member swing axis HC. As shown inFIG.16, the movement of the force applying member152L assembled to the non-drive-side bearing127in the direction of the force applying member swing axis HE is restricted by the contact of the second retainer127fwith the separation holding member151L.

FIG.31is a view of the process cartridge100after the assembly of the separation holding member151L as viewed in the separation holding swing axis (H) direction. It is a sectional view in which a part of the non-drive-side cartridge cover member117is partially cut out along a partial cross-sectional line CS so that the fitting portion between the oblong support receiving portion151La of the force applying member152L and the cylindrical portion127eof the non-drive-side bearing127can be seen. Here, the non-drive-side separation and contact mechanism150L is provided with a tension spring153as an urging means for urging the separation holding member151L to rotate in the direction of arrow B1about the separation holding swing axis H and for urging the force applying member152L in the direction of arrow B3. The arrow B3direction is substantially parallel to the longitudinal direction LH2direction (seeFIG.29) of the oblong support receiving portion152La of the force applying member152L. The tension spring153is stretched between a spring hooked portion151Lg provided on the separation holding member151L and a spring hooked portion152Ls provided on the force applying member152L. The tension spring153applies force in the direction of arrow F2inFIG.31to the spring hooked portion151Lg of the separation holding member151L, thereby applying an urging force to rotate the separation holding member in the direction of arrow B1. In addition, the tension spring153applies a force, in the arrow F1direction, to the spring hooked portion152Ls of the force applying member152L, thereby applying an urging force to move the force applying member152L in the arrow B3direction.

An angle formed between a line GS connecting the spring hooked portion151Lg of the separation holding member151L and the spring hooked portion152Ls of the force holding member152L, and a line HS connecting the spring hooked portion152Ls of the force applying member152L and the force applying member swing axis HE is selected so as to satisfy the following formula (3), with the counterclockwise direction about the spring hooked portion152Ls of the force applying member152L being the positive direction. By this, the force applying member152L is urged to rotate in the BA direction in the about the force applying member swing axis HE as the center of rotation.

In this embodiment, the separation holding member151L and force applying member152L are mounted on the side (outside in the longitudinal direction) of the non-drive-side bearing127on which the non-drive-side cartridge cover member117is disposed in the direction of the swing axis K as shown inFIG.29. However, the position is not limited to such an example, and they may be disposed on the developing unit frame (125) side (inner side in longitudinal direction) of the non-drive-side bearing127, or the separation holding member151L and the force applying member152L may be disposed with the non-drive-side bearing127interposed therebetween. In addition, the arrangement order of the separation holding member151L and the force applying member152L may be exchanged. The non-drive-side bearing127is fixed to the developing unit frame125to form the developing unit109. The fixing method in this embodiment uses fixing screws145and an adhesive agent (not shown) as shown inFIG.16, but the fixing method is not limited to such an example, and another connecting method is satisfactory, such as heat welding, resin material.

Here, part (a) ofFIG.32and part (b) ofFIG.32are views in which the force applying member pivot shaft HE and the separation holding member151L inFIG.31are enlarged, and the non-drive-side cartridge cover member117and the a tension spring153and the separation holding member151L are partially cut out along a sectional line CS for better illustration. The force applying member152L brings the first retracted restricting surface152Lv of the force applying member152L in to contact with the second support portion127eof the non-drive-side bearing127, by the urging force of the tension spring153in the direction of the arrow F1. In addition, as shown in part (b) ofFIG.32, the first pressing surface152Lq of the force applying member152L contacts the first pressed surface127hof the non-drive-side bearing127and is positioned. This position is referred to as a retracted position (reference position) of the force applying member152L. Further, the separation holding member151L is rotated in the arrow B1direction about the separation holding swing axis H by the urging force of the tension spring153in the arrow F2direction, and it is positioned by the contact surface151Lp of the separation holding member151L contacting the second pressing surface152Lr of the force applying member152L. This position is referred to as the separation holding position (restriction position) of the separation holding member151L. When the force applying member152L moves to the projecting position which will be described hereinafter, the second pressed surface151Le of the force applying member151L comes into contact with the second pressing surface152Lr of the force applying member152L, so that the force applying member152L can be positioned at the separation holding position.

FIG.33is an enlarged view of the separation holding member151L and the surroundings thereof inFIG.31, omitting the tension spring153, for better illustration. It is assumed that the process cartridge100including the non-drive-side separation and contact mechanism150L is dropped off in the direction of arrow JA inFIG.33during transportation. At this time, the separation holding member151L receives a force for rotation in the arrow B2direction about the separation holding swing axis H by its own weight. For the reason described above, when the separation holding member151L begins to rotate in the arrow B2direction, the rotation preventing surface151Ln of the separation holding member151L contacts the locking surface152Lu of the force applying member152L, and the separation holding member151L receives a force in the direction of the arrow F4for suppressing rotation in the arrow B2direction. By this, it is possible to constrain the separation holding member151L from rotating in the direction of the arrow B2during transportation, thereby preventing impairment of the separation state between the photosensitive drum104and the developing unit109.

In this embodiment, the tension spring153is used as the urging means for urging the separation holding member151L to the separation holding position and the force applying member152L to the retracted position, but is not limited to such an example. For example, a torsion coil spring, a leaf spring, or the like may be used as urging means to urge the force applying member152L to the retracted position and the separation holding member151L to the separation holding position. The material of the urging means may be metal, mold, or the like, as long as it has elasticity and can urge the separation holding member151L and the force applying member152L.

As described above, the developing unit109provided with the non-drive-side separation and contact mechanism150L is integrally coupled with the drum unit108by the non-drive-side cartridge cover member117as described above (state ofFIG.30). As shown inFIG.16, the non-drive-side cartridge cover117of this embodiment has a contact surface117c. The contact surface117cis a surface parallel to the swing axis K. In addition, as shown inFIGS.16and30when the non-drive-side cartridge cover member117is assembled to the developing unit109and the drum unit, the contact surface117cfaces the holding surface151Lc of the separation holding member151L positioned at the separation holding position. Here, the process cartridge100is provided with a developing pressure spring134as an urging member for bringing the developing roller106into contact with the photosensitive drum104. The development pressure spring134is stretched between the spring hooked portion117eof the non-drive-side cartridge cover member117and the spring hooked portion127kof the non-drive-side bearing127. By the urging force of the developing pressure spring134, the separation holding surface151Lc of the separation holding member151L and the contact surface117cof the non-drive-side cartridge cover member117contact with each other. Then, when the contact surface117cand the separation holding surface151Lc contact each other, the attitude of the developing unit109is determined such that the developing roller106of the developing unit109and the photosensitive drum104are spaced from each other by the gap P1. Thus, the state where the developing roller106is spaced from the photosensitive drum104by the gap P1by the separation holding member151L is referred to as a spaced position (retracted position) of the developing unit109(see part (a) ofFIG.34).

Referring toFIG.34, The separated state and contact state of the process cartridge100will be described in detail.FIG.34is a side view of the process cartridge100mounted inside the image forming apparatus main assembly170as viewed from the non-drive-side. Part (a) ofFIG.34shows a state in which the developing unit109is spaced from the photosensitive drum104.FIG.34Bshows a state in which the developing unit109is in contact with the photosensitive drum104.

First, in a state in which the separation holding member151L is positioned at the separation holding position and the developing unit109is positioned at the separation position, by the pushed portion152Le of the force applying member152L being pushed in the direction of the arrow ZA, the projection152Lh of the force applying member152L projects from the process cartridge100(state shown in part (a) ofFIG.34). This position is referred to as the projecting position of the force applying member152L. The second pressed surface151Le of the separation holding member151L is in contact with the second pressing surface152Lr of the force applying member152L by the tension spring153as described above. Therefore, when the second force receiving portion152Ln is pressed in the direction of arrow W42, the force applying member152L rotates in the direction of arrow BD about the force applying member swing axis HE to rotate the separation holding member151L in the direction of arrow B5. When the separation holding member151L rotates in the arrow B5direction, the separation holding surface151Lc is separated from the contact surface117c, and the developing unit109becomes rotatable in the arrow V2direction about the swing axis K from the separation position. That is, the developing unit109rotates in the V2direction from the separated position, so that the developing roller106of the developing unit109comes into contact with the photosensitive drum104. Here, the position of the developing unit109in which the developing roller106and the photosensitive drum104are in contact with each other is referred to as a contact position (developing position) (state shown in part (b) ofFIG.34). A position where the separation holding surface151Lc of the separation holding member151L is separated from the contact surface117cis referred to as a separation release position (permitting position). When the developing unit109is positioned at the contact position, the second restricted surface151Lk of the separation holding member151L contacts the second regulating surface117dof the drive-side cartridge cover member116, thereby maintaining the separation holding member151L in the separation release position.

In addition, the non-drive-side bearing127of this embodiment has a first pressed surface127hwhich is a surface perpendicular to the swing axis K. The non-drive-side bearing127is fixed to the developing unit109, and therefore, when the first force receiving portion152Lk of the force applying member152L is pressed in the direction of the arrow41while the developing unit109is in the contact position, the first pressing surface152Lq is brought into contact with the first pressed surface127h, so that the developing unit109rotates in the direction of the arrow V1about the swing axis K and moves to the separated position (state in part (a) ofFIG.34). Here, the direction in which the first pressed surface127hmoves when the developing unit109moves from the contact position to the spaced position is indicated by an arrow W41in part (a) ofFIG.34and part (b) ofFIG.34. The direction opposite to the arrow W41is the arrow W42direction, and the directions of the arrows W41and W42are substantially horizontal directions (X1and X2directions). The second force receiving surface152Lp of the force applying member152L assembled to the developing unit109as described above is placed upstream of the first pressed surface127hof the non-drive-side bearing127in the direction of the arrow W41. Further, the first pressed surface127hand the second force receiving surface151Le of the separation holding member151L are arranged at positions by which at least parts thereof overlap with each other in the W1and W2directions. The operation of the non-drive-side separation and contact mechanism150L inside the image forming apparatus main assembly170will be described below.

[Mounting of Process Cartridge to Image Forming Apparatus]

Referring toFIGS.35and36, engagement operation between the separation and contact mechanism150R of the process cartridges100Y and100K and the development separation control unit196of the image forming apparatus main assembly170at the time when the process cartridge100is mounted in the image forming apparatus main assembly170will be described. For better illustration, these Figures are cross-sectional views in which a part of the development cover member128and a part of the non-drive-side cartridge cover member117are omitted along a partial cross-sectional line CS.FIG.3is a view of the process cartridge100as viewed from the drive-side, at the time when the process cartridge100is mounted on the cartridge tray171(not shown) of the image forming apparatus M and the cartridge tray171has been inserted into the first mounting position, in which the parts other than the process cartridge100, the cartridge pressing unit121and the separation control member196L are omitted.

As described above, the image forming apparatus main assembly170of this embodiment has the separation control members196L corresponding to respective process cartridges100as described above. The separation control member196L is disposed closer to the lower surface side of the image forming apparatus main assembly170than the separation holding member151L when the process cartridge100is positioned at the first inner position and the second inner position. The separation control member196L projects toward the process cartridge100and is provided with a first force applying surface196La and a second force applying surface196Lb facing each other with a space196Rd therebetween. The first force applying surface196Ra and the second force applying surface196Rb are connected with each other by way of a connecting portion196Rc on the lower surface side of the image forming apparatus main assembly170. The separation control member196R is supported by the control metal plate197rotatably about a rotation center196Re. The separation member196R is always urged in the E1direction by an urging spring. In addition, the separation control member196R is structured to be movable in the W41and W42directions by the control metal plate197which is movable in the W41and W42directions by a control mechanism (not shown).

As described above, in interrelation with the transition of the front door11of the image forming apparatus main assembly170from the open state to the closed state, the cartridge pressing unit121descends in the direction of the arrow ZA, so that the first force application portion121ais brought into contact with the pushed surface152Lf of the force applying member152L. Thereafter, when the cartridge pressing unit121is lowered to the predetermined position, which is the second mounting position, the force applying member152Lh moves to the projecting position downward in the Z2direction of the process cartridge100(state shown inFIG.36). When this operation is completed, as shown inFIG.36, the gap T4is formed between the first force applying surface196La of the separation control member196L and the first force receiving surface152Lp of the force applying member152L, and the gap T3is formed between the second force applying surface196Lb and the second force receiving surface152Lp. Then, it is positioned at the second mounting position where the separation control member196L does not act on the force applying member152L. This position of the separation control member196L is referred to as a home position. At this time, the first force receiving surface152Lp of the force applying member152L and the first force applying surface196La of the separation control member196L are arranged so as to partially overlap in the W1and W2directions. Similarly, the second force receiving surface152Lp of the force applying member152L and the second force applying surface196Lb of the separation control member196L are arranged so as to partially overlap in the W1and W2directions.

[Contacting Operation of Developing Unit]

FIGS.36to38, the operation of contact between the photosensitive drum104and the developing roller106by the non-drive-side separation and contact mechanism150L will be described in detail. These Figures are sectional views, in which, a part of the development cover member128, a part of the non-drive-side cartridge cover member117, and a part of the non-drive-side bearing127are omitted along a partial cross-sectional line CS, for the sake of better illustration.

As described above, the development input coupling32receives a driving force from the image forming apparatus main assembly170in the direction of the arrow V2inFIG.24. That is, the developing unit109provided with the development input coupling32receives torque in the direction of the arrow V2from the image forming apparatus main assembly170about the swing axis K. Further, the developing unit109is urged also in the direction of the arrow V2by the urging force of the developing pressure spring134described above. As shown inFIG.36, when the developing unit109is in the separated position and the separation holding member151L is in the separation holding position, even if the developing unit109receives this torque and the urging force of the developing pressure spring134, the holding surface151Lc of the separation holding member151L contacts the contact surface117cof the non-drive-side cartridge cover member117, so that the attitude of the developing unit109is maintained at the separated position (state shown inFIG.36).

The separation control member196L of this embodiment is structured to be movable in the direction of arrow W41inFIG.36from the home position. When the separation control member196L moves in the W41direction, the second force applying surface196Lb of the separation control member196L and the second force receiving surface152Lp of the force applying member152L come into contact with each other, so that the force applying member152L is rotated in the direction of BD about the force applying member swing axis HD. Further, as the force applying member152L rotates, the separation holding member151L is rotated in the B5direction, while the second pressing surface152Lr of the force applying member152L is in contact with the second pressed surface151Le of the separation holding member151L. Then, the separation holding member151L is rotated by the force applying member152L to the separation release position where the separation holding surface151Lc and the contact surface117care separated from each other. Here, the position of the separation control member196L where the separation holding member151L is moved to the separation release position shown inFIG.37is referred to as the first position.

When the separation holding member151L is moved to the separation release position by the separation control member196L, the developing unit109is rotated in the direction V2by the torque received from the image forming apparatus main assembly170and the urging force of the developing pressure spring134to the contact position (state inFIG.37) where the developing roller106and the photosensitive drum104contacts each other. At this time, the separation holding member151L, which is urged in the arrow B4direction by the tension spring153, is maintained in the separation release position by the contact of the second restricted surface151Lk with the second regulating surface117dof the non-drive-side cartridge cover member117. Thereafter, the separation control member196L moves in the W42direction and returns to the home position. At this time, the force applying member152L is rotated in the BC direction by the tension spring153, and the state shifts to a state in which the first pressing surface152Lq of the force applying member152L is in contact with the first pressed surface127hof the non-drive-side bearing127(state ofFIG.38). By this, the above-described gaps T3and T4are formed again, and the separation control member196L is in the position where it does not act on the force applying member152L. The transition from the state shown inFIG.37to the state shown inFIG.38is performed immediately. The position of the separation control member196L inFIG.38is the same as inFIG.36.

As described above, in the structure of this embodiment, the separation control member196L is moved from the home position to the first position, thereby rotating the force applying member152L and moving the separation holding member151L from the separation holding position to the separation release position. This makes it possible that the developing unit109to move from the separated position to the contact position where the developing roller106and the photosensitive drum104contact each other.

[Separating Operation of Developing Unit]

Referring toFIGS.38and39, the movement of the developing unit109from the contact position to the separation position will be described in detail.FIG.39is a cross-sectional view in which, for the sake of better illustration, a part of the development cover member128, a part of the non-drive-side cartridge cover member117, and a part of the non-drive-side bearing127are omitted along a partial cross-sectional line CS.

The separation control member196L in this embodiment is structured to be movable in the direction of arrow W42inFIG.38from the home position. When the separation control member196L moves in the W42direction, the second force applying surface196Lb and the first force receiving surface152Lm of the force applying member152L come into contact with each other, so that the force applying member152L rotates about the arrow BC around the force applying member swing axis HD. Since the first pressing surface152Lq of the force applying member152L is in contact with the first pressed surface127hof the non-drive-side bearing127, the developing unit109rotates from the contact position in the direction of the arrow V1about the pivot axis K (state inFIG.39). At this time, the pushed surface152Lf of the force applying member152L has the arc shape, and the center of the arc is aligned with the swing axis K. By this, when the developing unit109moves from the contact position to the separated position, the force received by the pushed surface152Lf of the force applying member152L from the cartridge pressing unit121is directed in the direction of the swing axis K, the operation is not hindered in the rotation of the developing unit109in the direction of arrow V1. As regards the separation holding member151L, the second restricted surface151Lk of the separation holding member151L and the second regulating surface117dof the non-drive-side cartridge cover member117are separated from each other, so that the separation holding member151L is rotated in the arrow B4direction by the urging force of the tension spring153. By this, the separation holding member151L rotates until the second pressed surface151Le comes into contact with the second pressing surface152LR of the force applying member152L, and by the contact, it moves to the separation holding position. When the developing unit109is moved by the separation control member196L from the contact position toward the separation position and the separation holding member151L is placed at the separation holding position a gap T5is formed between the separation holding surface151Lc and the contact surface117cas shown inFIG.39. Here, the position at which the separation holding member151can move to the separation holding position by rotating the developing unit109from the contact position toward the separation position is referred to as a second position of the separation control member196L.

Thereafter, when the separation control member196L moves in the direction of the arrow W41and returns from the second position to the home position, the developing unit109rotates, while the separation holding member151L is maintained at the separation holding position, in the direction of arrow V2by the torque received from the image forming apparatus main assembly170and the urging force of the development pressure spring134, so that the separation holding surface151Lc and the contact surface117care brought into contact with each other. In other words, the developing unit109is maintained at the separated position by the separation holding member151L, and the developing roller106and the photosensitive drum104are spaced by the gap P1(the state shown inFIG.36and part (a) ofFIG.34). By this, the above-described gaps T3and T4are formed again, and the separation control member196L is positioned at a position where it does not act on the force applying member152L (state shown inFIG.36). The transition from the state ofFIG.39to the state ofFIG.36is carried out immediately.

As described above, in the structure of this embodiment, the movement of the separation control member196L from the home position to the second position, the separation holding member151L is moved from the separation release position to the separation holding position. By the separation control member196L returning from the second position to the home position, the developing unit109becomes in the state of being maintained at the separation position by the separation holding member151L.

So far, the operations of the separation mechanisms provided on the drive-side of the process cartridges100Y and100K and the operations of the separation mechanism provided on the non-drive-side have been described separately, but in this embodiment, they operate in interrelation with each other. More particularly, when the developing unit109is placed at the separated position by the separation holding member151R, the developing unit109is placed at the separation position by the separation holding member151L at substantially the same time, and the same applies to the contact position. Specifically, the separation control member121R and the separation control member121L described inFIGS.23to27and35to39are integrally moved by a coupling mechanism (not shown). By this, the timing at which the separation holding member151R of the drive-side is positioned at the separation holding position is substantially the same as the timing at which, the separation holding member151L of the non-drive-side is positioned at the separation holding position, and timing at which the separation holding member151R is positioned at the separation release position is substantially the same as the timing at which the separation holding member151L is positioned at the separation release position. These timings may differ between the drive-side and the non-drive-side, but it is desirable that at least the timings of placing at the separation release position are the same in order to save the time elapse from the start of the printing job by the user to the output of the print. In this embodiment, the separation member swinging axes H of the separation holding member151R and the separation holding member151L are coaxial with each other, but this is not inevitable, and it will suffice if the timings of positioning at the separation release position are substantially the same. Similarly, the force applying member swing axis HC of the force applying member152R and the force applying member swing axis HE of the force applying member152L do not coincide with each other, but this is not inevitable, and it will suffice if the timings of positioning at the separation release position are substantially the same, as described above.

As described above, the drive-side and the non-drive-side have the same separation and contact mechanisms, and they operate substantially simultaneously, by which even if the process cartridge100is twisted or deformed in the longitudinal direction, variations in the amount of spacing along the longitudinal direction can be suppressed because the amount of spacing between the photosensitive drum104and developing roller106can be controlled at both ends in the longitudinal direction.

Further, according to this embodiment, by moving the separation control member196R (L) between the home position, the first position, and the second position in one direction (directions of arrows W41and W42), the contact state and spaced state between the developing roller106and the photosensitive drum104can be controlled. Therefore, it is possible to keep the developing roller106in contact with the photosensitive drum104only when image forming operation is performed, and keep the developing roller106spaced from the photosensitive drum104when image forming operation is not performed. Therefore, even if the image forming apparatus is left for a long period of time without image formation, the developing roller106and the photosensitive drum104are not deformed, and stable image formation can be performed.

Further, according to this embodiment, the force applying member152R(L) which acts on the separation holding member151R(L) to rotate and move can be positioned at the retracted position by the urging force of the tension spring153or the like. Therefore, when the process cartridge100is outside the image forming apparatus main assembly170, the process cartridge100does have a part projecting from the outermost shape of the body, and therefore, the size of the process cartridge100can be reduced.

Similarly, the force applying member152R(L) can be positioned at the retracted position by the urging force of the tension spring153or the like, and therefore, when the process cartridge100is mounted to the main assembly170of the image forming apparatus, the mounting operation can be completed by moving it in only direction. Therefore, it is not necessary to move the process cartridge100(tray171) vertically. Therefore, the size of the image forming apparatus main assembly170can be reduced without requiring additional space.

Further, according to this embodiment, when the separation control member196R(L) is positioned at the home position, no load is applied from the process cartridge100to the separation control member196R(L). For this reason, the rigidity required for the separation control member196R(L) and the mechanism for operating the separation control member196R(L) can be reduced, and the size can be reduced. In addition, the load on the sliding portion of the mechanism for operating the separation control member196R(L) is also reduced, and therefore, it is possible to suppress the wear of the sliding portion and the generation of abnormal noise.

Furthermore, according to this embodiment, the developing unit109can maintain the separated position only by the separation holding member151R(L) of the process cartridge100. Therefore, by reducing the number of parts which causes variation in the amount of spacing between the developing roller106and the photosensitive drum104, the tolerance of parts can be eased and the amount of separation can be minimized. Since the amount of separation can be reduced, in the image forming apparatus main assembly170, the area occupied by the developing unit109when the developing unit109moves between the contact position and the separated position becomes smaller, and the image forming apparatus can be downsized correspondingly. In addition, since the space for the developer container29of the developing unit109which moves between the contact position and the separated position can be increased, it is possible to place a compact and large capacity process cartridge100in the image forming apparatus main assembly170.

Further, according to this embodiment, the force applying member152R(L) can be positioned at the retracted position when the process cartridge100is mounted, and the developing unit109can be maintained at the separated position only by the separation holding member151R(L) of the process cartridge100. Therefore, when the process cartridge100is mounted to the image forming apparatus main assembly170, the mounting operation can be completed by moving the process cartridge100in only one direction. Therefore, it is not necessary to move the process cartridge100(tray171) vertically. Therefore, the size of the image forming apparatus main assembly170can be reduced without requiring additional space. In addition, since the spacing amount can be reduced, when the process cartridge100is placed in the image forming apparatus main assembly170, the area occupied by the developing unit109when the developing unit109moves between the contact position and the spaced position becomes smaller, the size of the image forming apparatus can be reduced. In addition, since the space for the developer container29of the developing unit109which moves between the contact position and the separated position can be increased, it is possible to place a compact and large-capacity process cartridge100in the image forming apparatus main assembly170.

[Details of Layout of Separation and Contact Mechanism]

Referring toFIGS.40and41, the arrangement of the separation and contact mechanisms R and L in this embodiment will be described in detail.FIG.40is an enlarged view of the separation holding member151R and the surroundings thereof when the process cartridge100Y is viewed from the drive-side along the swing axis K (photosensitive drum axial direction) of the developing unit109. In addition, it is a cross-sectional view in which a part of the development cover member128and a part of the drive-side cartridge cover member116are omitted along a cross-sectional line CS for better illustration.FIG.41is an enlarged view of the separation holding member151R and the surroundings thereof when the process cartridge100is viewed from the non-drive-side along the swing axis K (photosensitive drum axis direction) of the developing unit109. In addition, it is a cross-sectional view in which a part of the development cover member128and a part of the drive-side cartridge cover member116are omitted along a partial cross-sectional line CS for better illustration. Regarding the arrangement of the separation holding member and the force applying member described below, there is no distinction between the drive-side and the non-drive-side, except for the portion that will be described in detail hereinafter, and therefore, the description will be made only as to the drive-side.

As shown inFIG.40, a point M1is the rotation center of the photosensitive drum104, a point M2is the rotation center of the developing roller106, and a line N is a line passing through the points M1and M2. In addition, a contact area between the separation holding surface151Rc of the separation holding member151R and the contact surface116cof the drive-side cartridge cover member116is indicated by M3, and a contact area between the second pressed surface151Re of the separation holding member151R and the second pressing surface152Rr of the force applying member152R is indicated by M4. Further, a distance between the swing axis K of the developing unit109and the point M2is distance e1, a distance between the swing axis K and the area M3is distance e2, and a distance between the swing axis K and the point M4distance e3.

In the structure of this embodiment, the following positional relationship is satisfied when the developing unit109is at the separated position and the force applying member152R(L) is at the projecting position. That is, as viewed along the axial direction of the swing axis K (the axial direction of the photosensitive drum) shown inFIG.40, at least a part of the contact area M3between the separation holding member151R and the drive-side cartridge cover member is disposed in an area on the opposite side of the area where the center of the development coupling32(swing axis K) exists, with a line N passing through the center of the drum104and the center of the developing roller106interposed therebetween. In other words, the separation holding surface151Rc of the separation holding member151R is arranged such that the distance e2is longer than the distance e1.

By arranging the separation holding member151R and the separation holding surface151Rc in this manner, when the position of the separation holding surface151Rc varies due to tolerance of parts or the like, variations in the attitude of the separation position of the developing unit109can be suppressed. In other words, the influence of variations in the separation holding surface151Rc on the spacing amount (gap) P1(see part (a) ofFIG.34) between the developing roller106and the photosensitive drum104can be minimized, and the developing roller106can be spaced from the photosensitive drum104with high precision. Further, there is no need to provide an extra space for retracting the developing unit109when it is in the separated position, which leads to downsizing of the image forming apparatus main assembly170.

Further, the first force receiving portion152Rk (Lk) and the second force receiving portion152Rn (Ln), which are the force receiving portions of the force applying member152R (L), are disposed on the opposite side of the side in which the rotation center of the development coupling32is provided with the extension of the line N interposed therebetween. As described above, the force receiving portions152Rk (Lk) and152Rn (Ln) are arranged at the ends in the longitudinal direction. Further, as shown inFIG.15(FIG.16), a cylindrical portion128b(127a), which is a support portion for the developing unit109, is provided at the end portion in the longitudinal direction. Therefore, by placing the force receiving portions152Rk (Lk) and152Rn (Ln) on the opposite side of the line N from the cylindrical portion128b(127a) (that is, the swing axis K) of the developing unit109, functional portions can be arranged efficiently. In other words, the size of the process cartridge100and the image forming apparatus M can be reduced.

In addition, the force receiving portions152Rk,152Rn are arranged at the longitudinal drive-side ends. Further, as shown inFIG.15, a development drive input gear132which receives drive from the image forming apparatus main assembly170and drives the developing roller106is provided at the drive-side end in the longitudinal direction. As shown inFIG.40, the force applying members152Rk and152Rn are arranged on the opposite side of the side in which the rotation center K of the development drive input gear132(development coupling portion132a) indicated by the broken line is provided, with an extension of the line N interposed therebetween. With this arrangement, the functional portions can be arranged efficiently. In other words, the size of the process cartridge100and the image forming apparatus M can be reduced.

Further, the contact portion between the separation holding member151R and the force applying member152R is disposed such that the distance e3is longer than the distance e1. By this, the separation holding member151R and the drive-side cartridge cover member116can be contacted with each other with a lighter force. In other words, the spacing between the developing roller106and the photosensitive drum104can be stably performed.

Next, a detailed description will be made as to a structure in which the photosensitive drums104of the process cartridges100M and100C and the developing roller106of the developing unit109are spaced from each other and contacted with each other. As described above, the developing unit109of the process cartridge100Y, the developing unit109of the process cartridge100M, and the developing unit109of the process cartridge100C are connected by the connecting member201.

First, referring toFIG.42, the structure of the connecting member will be described. Part (a) ofFIG.42is a perspective view of the process cartridge100and the tray171wherein the process cartridge100is mounted on the tray171, the connecting member201is dismountably mounted to the process cartridges100Y,100M, and100C, and the front door closed. Since the position and attitude of the process cartridge100are fixed as described above in the state of part (a) ofFIG.42, the position of the swing axis K of the developing unit109of the process cartridge100is fixed. Part (b) ofFIG.42is a perspective view of the same state as part (a) ofFIG.42but is a view before the connecting member201is mounted.

As shown inFIG.42, the connecting member201is provided (removably mounted) on the upper portion of the process cartridges100Y,100M and100C. Support shafts202Y,202M and202C extend substantially parallel to the axial direction of the photosensitive drums, and are provided on tops of the developing units109Y,109M and109C, respectively. The connecting member201is a plate-shaped member provided with three grooves (engaging portions/connecting portions)2011Y,2011M, and2011C which are open downward. The connecting member201is supported rotatably with respect to the support shafts202Y,202M and202C by engagement (connect) between groove portions2011Y,2011M, and2011C and the support shafts (engaged portions/connected portions)202Y,202M and202C provided on the developing units109Y,109M and109C, respectively. At this time, a line connecting the support shafts202Y,202M and202C and a line connecting the swing shafts KY, KM and KC of the process cartridges100Y,100M and100C are parallel to each other, and the distance between support shaft202Y and the support shaft202M is made equal to the swing axis KY of the process cartridge100Y and the swing axis KM of the process cartridge100M. In addition, and the distance between support shaft202M and the support shaft202C is made equal to the swing axis KM of the process cartridge100M and the swing axis KC of the process cartridge100C. That is, a parallel linkage mechanism is formed by the swing shafts KY, KM, KC and the support shafts202Y,202M,202C which are joints of link.

After the process cartridge100is mounted on the tray171as described above, the connecting member201is mounted downward (Z2direction in part (b) ofFIG.42from above. At that time, the grooves2011Y,2011M, and2011C of the above-described connecting member are fitted to the support shafts202Y,202M, and202C of the process cartridge100, respectively. At this time, a retaining portion may be provided in the groove portion2011so that the connecting member does not drop off the process cartridge100.

Next, referring to part (a) ofFIG.43and part (b) ofFIG.43, the separating and contacting operations of the process cartridges100M and100C will be described. Part (a) ofFIG.43and part (b) ofFIG.43are drive-side side view of the process cartridges, wherein the connecting member201is mounted on the process cartridge100Y, the process cartridge100M and the process cartridge100C, the process cartridges100Y,100M,100C and100K are mounted on the tray171, and the front door is closed. Part (a) ofFIG.43shows a state in which the photosensitive drums104and the developing rollers106are spaced from each other, and part (b) ofFIG.43shows a state in which the photosensitive drums104and the developing rollers106are in contact with each other. In the states of part (a) ofFIG.43and part (b) ofFIG.43, as described above, a parallel linkage mechanism is formed by the swing shafts KY, KM, and KC and the support shafts202Y,202M, and202C as joints, and the swing attitudes of the swing axes KY, KM, and KC of109Y,109M, and109C are kept the same. That is, when the developing unit109Y of the process cartridge100Y including the separation and contact mechanism150is at the separated position as shown in part (a) ofFIG.43, the developing units109M and109C are also at the separated position. As the attitude of the developing unit109Y shifts from the separated position to the contact position, the attitudes of the developing units109M and109C also shift from the separated position to the contact position, resulting in the state shown in part (b) ofFIG.43. The same applies when the attitude of the developing unit109Y shifts from the contact position to the separation position.

In this embodiment, the connecting member201is one parallel link rotatably supported by the support shafts202Y,202M, and202C, but as shown inFIG.44, it may comprise two links which are rotatably supported on two supporting shafts, respectively.FIG.44is a perspective view of the process cartridges100Y,100M,100C and100K inside the main assembly with the front door closed. Grooves2011Y1and2011M1of connecting member201YM are rotatably supported by support shafts202Y and202M, respectively, and grooves2011M2and2011C1of connecting member201MC are rotatably supported by support shafts202M and202C, respectively. The connecting member201YM is rotatably supported by the support shafts202Y and202M, and therefore, the distance between the support shafts202Y and202M is kept constant. In addition, as described above, when the main assembly front door is closed, the positions of the swing shafts KY, KM, and KC are fixed. Therefore, because of the action of the connecting member201YM, a parallel linkage mechanism is established by the swing shafts KY and KM of the process cartridges100Y and100M and the support shafts202Y and202M as joints, and the swing attitudes of the developing units109Y and109M about the swing shafts KY and KM are kept the same. Similarly, because of the action of the connecting member201MC, the swing attitudes of the developing units109M and109C about the swing shafts KM and KC are kept the same. As described above, the swing attitudes of the developing units109Y,109M, and109C about the swing axes KY, KM, and KC are kept the same, and therefore, the developing units109M and109C are moved in interrelation with the separation and contact operations of the developing unit109Y.

In this embodiment, the process cartridge having the separation and contact mechanism150among the process cartridges100Y,100M, and100C is the process cartridge100Y, but the present invention is not limited to such an example. In addition, two process cartridges may be provided with the separation and contact mechanism150.FIG.45is a perspective view of the process cartridges100Y,100M,100C and100K inside the main assembly with the front door closed. For example, as shown in part (a) ofFIG.45, only the process cartridge100M may have the separation and contact mechanism150. Similarly, as shown in part (b) ofFIG.45, only the process cartridges100Y and100C may have the separation and contact mechanism150. Here, part (a) ofFIGS.45and45(b) show the non-drive-side separation and contact mechanism150L. In addition, although not shown, only the process cartridge100C may have the separation and contact mechanism150. Only the process cartridges100Y and100M may have the separation and contact mechanism150. Only the process cartridges100M and100C may have the separation and contact mechanism150. In any of the above-described cases, it will suffice if the connecting member201is rotatably connected to the developing unit or units of the process cartridge or cartridges which do not have all the separation and contact mechanism and to the developing unit or units of the process cartridge or cartridges which have the separation and contact mechanism. For example, in part (b) ofFIG.45, although connecting members201YM and201MC are provided, it will suffice if either one of them is provided.

Also, in this embodiment, the support shaft is provided at the top part of the developing unit, but this is not the only possibility. Part (a) ofFIG.46is a perspective view of the connecting member and the process cartridge in a state where the connecting member201and the process cartridge100are mounted on the tray171and the front door is closed. Part (b) ofFIG.46shows the same state as part (a) ofFIG.46, but the connecting member201is not shown. As shown in part (a) ofFIG.46and part (b) ofFIG.46, support shafts203Y,203M and203C may be provided on the side surfaces of developing units109Y,109M and109C. In addition, in this embodiment, one support shaft203Y, one support shaft203M, and one support shaft203C are on the drive-side (the side including the driving structure) of respective developing unit in the longitudinal direction of the process cartridge, but the present invention is not limited to such an example. For example, each developing unit may have one supporting shaft provided on the non-drive-side (the end in the Y2direction in part (a) ofFIG.43and part (b) ofFIG.43), or may be provided with one on each side.

In this embodiment, the user assembles the connecting member201to the process cartridges100Y,100M, and100C mounted on the tray171, but this is not the only one option. Part (a) ofFIG.47and part (b) ofFIG.47are perspective views of the process cartridges100Y,100M,100C1and100K and the tray171. As shown in part (a) ofFIG.47, the connecting member204is provided on the process cartridge100C1and is rotatably supported by the support shaft202c. As shown in part (a) ofFIG.47, the process cartridges100Y,100M, and100K are first mounted on the tray171, and then the process cartridge100C1is mounted on the tray171, and a groove portion2041Y and a groove portion2041M of the connecting member204are engaged with the support shafts202Y and202M of the process cartridges100Y and100M, respectively, as shown in part (b) ofFIG.47. However, the connecting member204is not provided limitedly on the process cartridge100C1, and may be provided on the process cartridge100Y or the process cartridge100M.

In this embodiment, the connecting member201is rotatably supported by the support shafts202Y,202M, and202C provided on the process cartridges100Y,100M, and100C, but the present invention is not limited to such an example.FIG.48is a perspective view of a state in which the process cartridge100is mounted to the tray171and the connecting member205is mounted. The connecting member205is a member (flexible material, such as a string-like member) capable of transmitting force in the tensile direction but not capable of transmitting force in the compressive direction, and is connected with the developing unit109Y,109M and109C of the process cartridges100Y,100M and100C. Although many connection methods are available, for example, they may be fastened with screws. Since the connecting member205is made of a flexible material, it cannot transmit a force in the compressive direction. Therefore, in the case that the connecting member205is provided and the upper part of the developing unit as shown inFIG.48, the separation and contact mechanism150is provided on the process cartridge100C. As another alternative, the connecting member is provided with a projection shape such as a boss or rib, the process cartridge is provided with a recess shape such as a groove or step, and the projection shape is engaged with the recess shape. In any case, the connecting member may be dismountably mounted to at least one cartridge. Further, it will suffice if the connecting member is removable from the main assembly of the image forming apparatus by the connecting member being removed from the cartridge or by the process cartridge being removed from the main assembly of the image forming apparatus.

Heretofore, the description has been made as to examples in which at least one of the process cartridges100Y,100M, and100C has the separation and contact mechanisms150R and150L, and the separation and contact mechanisms150R and150L are each provided with force applying members152R and152L, but the present invention is not limited to such an example.FIG.49is a perspective view wherein, a process cartridge300including no force application member as a separation and contact mechanism is mounted on a tray (not shown), and a connecting member301is mounted on the process cartridges300Y,300M, and300C, in the state of having been mounted in the main assembly. The process cartridge300Y performs a contact separation operation by an operation which will be described hereinafter. Similarly to the above-described contact separation operation of the process cartridges100M and100C the process cartridges300M and300C also perform the contact separation operation synchronism with the contact separation operation of the process cartridge300Y by way of the action of the connecting member301.

Referring to part (a) ofFIG.50and part (b) ofFIG.50, The description will be made as to the separation operation of the process cartridge300having no force application member as the separation/contact mechanism will be described. Part (a) ofFIG.50is a partial cross-sectional view of the process cartridge300and the separation control member396at the time when the process cartridge300is in the separated state, and part (b) ofFIG.50is a partial cross-sectional view of the process cartridge300and the separation control member396when the process cartridge300is in the contact state. When the developing unit309of the process cartridge300is in the spaced position (state shown in part (a) ofFIG.50), the separation holding member351rotatably provided on the developing cover member328abuts against a contact surface316tthe drive-side cartridge cover member316. By this, the developing unit309is maintained at the separated position. When the process cartridge300shifts from the separated state to the abutment state, the separation control member396moves in the W342direction, and contacts the separation holding member352, so that the separation holding member352rotates in the B35direction. Then, the developing unit309moves to the contact position about the swing axis K by the same mechanism as the contact operation of the process cartridge100including the separation and contact mechanism150, and the separation control member396returns to the home position (state of part (b) ofFIG.50). Next, referring to part (a) ofFIG.50and part (b) ofFIG.50, the separation operation will be described. When the developing unit309of the process cartridge300shifts from the contact position (the state shown in part (b) ofFIG.50) to the separated state, the separation control member396moves in the W343direction, and the developing unit309contacts the pressed surface328hso that developing unit rotates in the direction V31. Then, the developing unit309is maintained at the separated position by the separation holding member351by the same mechanism as the separation operation of the process cartridge100including the separation and contact mechanism150described above, and the separation control member396returns to the home position (FIG.50(state of a)).

INDUSTRIAL APPLICABILITY

There are provided a connecting member capable of connecting a plurality of process cartridges, a plurality of process cartridges connected by the connecting member, and an image forming apparatus including a plurality of process cartridges.

The present invention is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of the present invention. Accordingly, the following claims are attached to publicize the scope of the invention.

This application claims priority based on Japanese Patent Application No. 2020-156781 filed on Sep. 17, 2020, and the entire contents of the description are incorporated herein.