Patent Description:
Heretofore, in the field of an image forming apparatus which uses an electrophotographic image forming process, the process cartridge which includes a photosensitive drum and a developing roller which acts on the photosensitive drum and a developing unit which contains a developer (toner) to be used for the image formation as a unit is known. A developing cartridge type using the developing unit which does not include the photosensitive drum is also known. According to these cartridge types, a maintenance operation of a device can be carried out by the user without a service person, in effect. For this reason, these cartridge types are widely used for the electrophotographic image forming apparatus.

It is also known that a drawer for carrying the process cartridge or the developing cartridge is provided, and the exchange of the cartridge is capable by drawing this drawer from the inside of the main assembly to a predetermined position. According to this technique, the user can supply the developer easily, in effect.

Here, when the image formation is carried out by the image forming apparatus, the developing roller in the developing unit is in the state of being urged toward the photosensitive drum at a predetermined pressure. In a contact-type developing system in which the developing roller is contacted to the photosensitive drum during the developing operation, an elastic layer of the developing roller is in contact to a surface of the photosensitive drum at the predetermined pressure.

Therefore, when the developing unit is used for a long term in the state that it is mounted to the main assembly of the apparatus, the elastic layer of the developing roller may be deformed. This will result in occurrence of nonuniformity in the image by the developing operation. In addition, since the developing roller is in contact with the photosensitive drum, the developer is deposited on the photosensitive drum from the developing roller unnecessarily. Furthermore, since the photosensitive drum and the developing roller are contacted with each other and rotated even when the developing operation is not carried out, and therefore, the deterioration of the developer and the developing roller is accelerated as the case may be.

In order to suppress the acceleration of the deterioration, <CIT> discloses a mechanism by which the developing roller is spaced from the photosensitive drum when the image formation is not carried out.

In such a prior-art, a member (movable member) movable between a position for contacting the developing roller to the photosensitive drum and a position for spacing them is provided in a main assembly side of the apparatus. When a drawer member (tray) carrying the cartridge photosensitive drum and the developing roller enters the main assembly of the apparatus, the movable member is in the position away from a movement path of the drawer member. By a door being closed after the drawer member is inserted to a predetermined position in the main assembly of the apparatus, the movable member moves toward the cartridge carried on the drawer member to space the developing roller from the photosensitive drum.

However, in such conventional example, the movable member is provided in the main assembly side of the apparatus. Therefore, when the drawer member is moved into the main assembly of the apparatus, it is required that the movable member is retracted to the position not interfering with the drawer member. In addition, in order to space the developing roller from the photosensitive drum, it is necessary to move the movable member to the position of the cartridge on the drawer member. For this reason, the space is required in the main assembly of the apparatus in order to permit the movement of the movable member from the main assembly side of the apparatus to the cartridge position in the drawer member. This impedes downsizing of the main assembly of the apparatus.

<CIT> shows a drawer (drawer member, supporting member) usable with an image forming apparatus for forming an image on a recording material, which is movable in a state of supporting a plurality of developing cartridges that each include a developing roller for developing an electrostatic latent image formed on a photosensitive drum, the drawer being movable through a main assembly opening of the main assembly between an inside position in which the drawer is inside the main assembly and an outside position in which the drawer is outside the main assembly and in which the plurality of developing cartridges is detachably mountable, the drawer supporting a plurality of photosensitive drums.

Further drawers (drawer members, supporting members) according to the prior art are shown in <CIT>, <CIT> and <CIT>.

It is the object of the present invention to provide a drawer (drawer member, supporting member) usable with an image forming apparatus for forming an image on a recording material such the configuration of the drawer suppresses damage to a surface of a photosensitive drum due to a mounting operation of a developing cartridge being detachably mountable to a mounting portion of said drawer.

The object of the present invention is achieved by a drawer having the features of claim <NUM>.

It is an advantage of the present invention to provide a downsized electrophotographic image forming apparatus (image forming apparatus) in which a drawer (drawer member, supporting member) carrying a photosensitive drum and a developing unit is inserted into the main assembly of the apparatus, and in which the developing roller and the photosensitive drum can be contacted and spaced relative to each other.

In the following, embodiments of the present invention will be described in detail referring to the accompanying drawings. The dimensions, materials, shapes, positional relationships of the constituent elements of the embodiments are not restrictive to the present invention unless otherwise stated.

Referring to <FIG>, an electrophotographic image forming apparatus (image forming apparatus) according to Embodiment <NUM> of the present invention will be described.

Referring to <FIG> and <FIG>, the description will be made as to the general arrangement of the image forming apparatus according to Embodiment <NUM> of the present invention. <FIG> is a schematic sectional view of the image forming apparatus according to Embodiment <NUM> of the present invention. <FIG> is a schematic sectional view illustrating the state that the drawer unit in the image forming apparatus according to Embodiment <NUM> of the present invention is drawn.

In an image forming apparatus <NUM> according to this embodiment, the four electrophotographic photosensitive drums (photosensitive drums <NUM>) juxtaposed horizontally is employed. The photosensitive drum <NUM> is rotated in the clockwise direction in <FIG> by unshown driving means.

The image forming apparatus <NUM> includes the charging means <NUM>, a scanner unit <NUM>, a development unit 4y, <NUM>, 4c, <NUM>, and the electrostatic transfer means <NUM> and so on as electrophotographic image forming process means, in addition to the photosensitive drum <NUM>. The developing units 4y, <NUM>, 4c, <NUM> maybe simply called developing unit <NUM> where doing so is clear, although y represents yellow; m represents magenta; c represents cyan; and k represents black.

Here, the charging means <NUM> has the function of charging a surface of the photosensitive drum <NUM> uniformly. The scanner unit <NUM> projects a laser beam onto the photosensitive drum <NUM> on the basis of image information to form an electrostatic latent image on the surface of the photosensitive drum <NUM>. The developing unit <NUM> develops the electrostatic latent image formed on the surface of the photosensitive drum <NUM> using the toner which is a developer. The electrostatic transfer means <NUM> transfers a toner image on the photosensitive drum <NUM> onto a sheet material S as a recording material which is a transfer member. Specific examples of sheet material S include the paper, an OHP sheet, and cloth.

The image forming apparatus <NUM> includes cleaning means <NUM> for removing the toner which remains on the surface of the photosensitive drum after the transferring <NUM>. Furthermore, the image forming apparatus <NUM> further includes cleaning means <NUM> for removing the residual toner deposited on the transfer belt <NUM> below an electrostatic transfer belt (transfer belt <NUM>) as a transfer member which constitutes electrostatic transfer means <NUM>.

The photosensitive drum <NUM> includes an aluminum cylinder and an organic photoconductor layer (OPC photosensitive member) applied on an outer surface thereof, for example. The photosensitive drum <NUM> is supported by an unshown supporting member rotatably at the opposite ends thereof. One of the ends is provided with an unshown drum coupling for receiving a driving force from a driving motor (unshown). By this, the photosensitive drum <NUM> receives the driving force of the driving motor through the drum coupling to rotate clockwisely in <FIG>.

The charging means <NUM> according to this embodiment is means of a contact charging type. More specifically, the charging means <NUM> is an electroconductive roller in the form of the roller and contacts to the surface of the photosensitive drum <NUM>. A charging bias voltage is applied to this roller, by which the surface of the photosensitive drum <NUM> is charged uniformly.

The scanner unit <NUM> is disposed above the photosensitive drum <NUM>. In the scanner unit <NUM>, the image light (laser beam) corresponding to an image signal is emitted from an unshown laser diode and it is incident on the surface of the charged photosensitive drum <NUM>. By this, the electrostatic latent image corresponding to the image signal is formed on the surface of the photosensitive drum <NUM>.

The developing units <NUM> include the toner containers 41y, <NUM>, 41c, <NUM> which accommodates the yellow, the magenta, the cyan, and the black toner, respectively. The toner containers 41y, <NUM>, 41c, <NUM> are the developer accommodating portions which accommodate the developer (toner) to be supplied to the developing roller <NUM>. The toner in the toner containers 41y, <NUM>, 41c, and <NUM> is fed to a toner supplying rollers43. The toner is applied to the outer periphery of the developing roller <NUM>, and the charge is applied to the toner, by the toner supplying roller <NUM> and a developing blade <NUM> press-contacted to an outer periphery of the developing roller <NUM>.

By applying a developing bias to the developing roller <NUM>, the toner is deposited on a latent image formed on the photosensitive drum <NUM> to form the toner image. The opposition contact of the developing roller <NUM> is carried out to the photosensitive drum <NUM>. Here, the developing unit <NUM> and the photosensitive drum <NUM> form integral process cartridge P (Py, Pm, Pc, Pk). In the process cartridge P, the toner is consumed with usage, and when the lifetime ends, the process cartridge P can be exchanged (so-called cartridge type).

As shown in <FIG>, the image forming apparatus <NUM> includes the transfer belt <NUM> contacted to the photosensitive drum <NUM>. By the transfer belt <NUM>, the sheet material S is fed to a transfer position, where the toner image formed on the surface of the photosensitive drum <NUM> is transferred.

The inside of the transfer belt <NUM> is provided with a transfer roller <NUM> in a position opposed to the photosensitive drum <NUM>. From the transfer roller <NUM>, positive polarity charge is applied to the sheet material S through the transfer belt <NUM>. By this, the toner image (developer image) on the photosensitive drum <NUM> is transferred to the sheet material S.

The image forming apparatus <NUM> includes a feeding portion <NUM> for feeding the sheet material S to an image forming station. The feeding portion <NUM> includes a feeding cassette <NUM> for accommodating a plurality of sheet S. At the time of the image formation, a feeding roller <NUM> and a registration roller couple <NUM> rotate in accordance with the image forming operation. By this, the sheet material S is fed one by one from the cassette <NUM>. In synchronism with the rotation of the transfer belt <NUM> and the toner image, the sheet material S is fed by the registration roller pair <NUM> to the transfer belt <NUM>.

Furthermore, the image forming apparatus <NUM> includes a fixing portion <NUM> for fixing a plural color toner image transferred onto the sheet material S. The fixing portion <NUM> comprises a rotatable heating roller 21b and a pressing roller 21a press-contacted to it. While the sheet material S onto which the toner image on the photosensitive drum <NUM> is transferred is nipped between the heating roller 21b and the pressing roller 21a, it is fed, during which the heat and a pressure are applied to the toner. By this, the plural color toner image is fixed on the surface of the sheet material S.

An image forming process is as follows. When the image forming operation is started, the photosensitive drum <NUM> is rotated. The charging means <NUM> applies the charge uniformly to the surface of the photosensitive drum <NUM>, and the scanner unit <NUM> exposes the surface of the photosensitive drum <NUM> to the image light in response to the image signal to form an electrostatic latent image on the surface of the photosensitive drum <NUM>. The developing roller <NUM> develops the electrostatic latent image (With the toner).

On the other hand, to the sheet material S fed by the transfer belt <NUM> from the feeding portion <NUM>, the toner images formed on the surfaces of the photosensitive drums <NUM> is sequentially transferred by the electric fields formed between the photosensitive drums <NUM> and the transfer rollers <NUM>. The sheet material S onto which the four color toner images are transferred is fed to the fixing portion <NUM>. A color image is fixed with the fixing portion <NUM>, and the sheet material S is discharged from a discharging portion <NUM> to an outside of the device by a discharging roller pair <NUM>.

A drawer member <NUM> will be described. It is a supporting member, and is movable between an inside position dismountably supporting the process cartridge and an outside position of the outside of the main assembly.

Here, in this embodiment, the main assembly is the portion other than at least drawer member <NUM> and the members (parts) which are detachably mountable thereto or fixed thereto, among the various members (parts) which constitute the image forming apparatus <NUM>.

As shown in <FIG>, the drawer member <NUM> is movable linearly in the substantially horizontal direction (arrows D1 and D2 directions) relative to the main assembly (insertable and drawable). The drawer member <NUM> can be moved to the position (<FIG>) in which it is accommodated in an inside of the main assembly and the position (<FIG>) in which it is drawn to an outside the main assembly.

In the state that the drawer member <NUM> is in a drawn-out position, the process cartridges P (Py, Pm, Pc, Pk) is mounted by the user to the drawer member <NUM> in the substantially vertical direction (the direction of arrow C in <FIG>). In the process cartridge P mounted in this manner, a longitudinal direction (an axial direction of the developing roller <NUM>) thereof is perpendicular to a movement direction of the drawer member <NUM>. The four process cartridges Py, Pm, Pc, Pk are juxtaposed in the movement direction of the drawer member <NUM>.

In the state that such process cartridges P are mounted to the drawer member <NUM>, they are moved into the main assembly with the drawer member <NUM>. In the state that the drawer member <NUM> is in the main assembly, when a door <NUM> is closed, all the process cartridges are mounted to the predetermined positions in the main assembly P.

In this manner, according to the image forming apparatus <NUM> according to this embodiment, four process cartridge Ps can be mounted into the main assembly all together, and four process cartridges Ps can be drawn all together to the outside of the main assembly. Therefore, the operability in the exchange of process cartridge P is excellent, as compared with the case in which the process cartridges are mounted into the main assembly individually.

Referring mainly to <FIG>, the structures of the mounting portion for the drawer member <NUM> in the main assembly will be described. <FIG> are a perspective views illustrating the mounting portion for the drawer member in the main assembly of the image forming apparatus according to Embodiment <NUM> of the present invention. In <FIG>, the scanner unit <NUM> and so on are omitted among the members (parts) which constitute the main assembly, for better understanding of the structure of the mounting portion. <FIG> are the perspective views as seen in different directions.

On an inner wall surface of a main assembly frame, the pair of guide portions 14R, <NUM> which guide the movement direction of the drawer member <NUM> is provided opposed to each other. The guide portions 14R, <NUM> have the function of guiding the portions-to-be-guided 13a, 13b, 13c, and 13d (<FIG> and <FIG>) of the drawer member <NUM> as will be described hereinafter, and have a channel-like section. The guide portions 14R, <NUM> are extended in the substantially horizontal direction from the neighborhood of an entrance of the main assembly (neighborhood of the door <NUM>) to a rear side, so that the drawer member <NUM> can be guided from the position for drawing to an outside of the main assembly to the position of being accommodated in the inside of the main assembly.

Above the guide portions 14R, <NUM>, urging members <NUM>, <NUM> for pressing and positioning the process cartridge P to the predetermined position is provided. These urging members <NUM>, <NUM> press process cartridge P, by moving downwardly with the driving force from a main assembly side, and, thereby to position the process cartridge P in the predetermined position in the main assembly.

As shown in <FIG>, below a guide portion <NUM>, a drum coupling member <NUM> for transmitting a drive to a photosensitive drum <NUM> and a development coupling member <NUM> for transmitting the drive to the developing roller <NUM> are provided, and they are disposed at equal intervals in the horizontal direction. The drum coupling member <NUM> and the development coupling member <NUM> transmit the driving forces from an unshown driving source to the process cartridge P. In the state where the door <NUM> is opened, the drum coupling member <NUM> and the development coupling member <NUM> are in the state of retracting in the inside, and they enter into process cartridge P in interrelation with the closing operation of the door <NUM>.

As shown in <FIG>, furthermore, the rear side of the guide portion <NUM> is provided with a driving gear <NUM> for applying the driving force for moving the contacting and spacing member <NUM> as will be described hereinafter.

The drawer member <NUM> will be described in detail referring mainly to <FIG> and <FIG>. <FIG> and <FIG> are perspective views of the drawer unit in the image forming apparatus according to Embodiment <NUM> of the present invention. <FIG> and <FIG> are the perspective views, as seen from the different directions.

Four corners of the drawer member <NUM> are provided with the portions-to-be-guided 13a, 13b, 13c, 13d for being guided by the guide portions 14R, <NUM> of the main assembly. The portions-to-be-guided 13a, 13c are guided by the guide portion 14R, and the portions-to-be-guided 13b, 13d is guided by the guide portion <NUM>. The portions-to-be-guided 13a, 13b project from the outside of a side surface, and are extended in a drawing direction so that the drawer member <NUM> does not incline in the drawn-out position. The portions-to-be-guided 13c, 13d have cylindrical shapes and project from the outside of the side surface.

The one end portion of the drawer member <NUM> is provided with a grip portion <NUM> for the convenience at the time of the user operating the drawer unit U1.

Furthermore, the drawer member <NUM> is provided with the mounting portions 13f for mounting the process cartridge s P, as will be described hereinafter in an array. A partition plate <NUM> is provided between the mounting portions 13f, and a rough index at the time of mounting process cartridge P is provided. Lower portions of the mounting portions 13f are provided with opening portions 13e, respectively. Through these opening portions 13e, the photosensitive drum <NUM> provided in the process cartridge P can be contacted to the transfer belt <NUM>.

The one-end portions and the other end portions of the mounting portion 13f is provided with the guide portions <NUM>, 13i, 13j, <NUM> for mounting the process cartridge s P to the inside of the drawer member <NUM>. The lower portions of the guide portions <NUM>, 13j are provided with positioning portions 13h1, 13j1 for positioning the process cartridge P relative to the drawer member <NUM>.

As shown in <FIG>, the drawer member <NUM> is provided with an opening portion <NUM> for the entrance of the drum coupling member <NUM> and an opening portion <NUM> for the entrance of the development coupling member <NUM>. The drum coupling member <NUM> and the development coupling member <NUM> enter the opening portion <NUM> and the opening portion <NUM> in interrelation with the closing operation of the door <NUM>. The drum coupling member <NUM> and the development coupling member <NUM> which entered these opening portions <NUM>, <NUM> engage with the coupling member of the process cartridge P to enable the transmission of the drive to the process cartridge P.

One of the side surfaces of the drawer member <NUM> is provided with a contacting and spacing member <NUM>. The contacting and spacing member <NUM> is extended along the movement direction of the drawer member <NUM>, and is movable in the movement direction (direction of arrow D in <FIG>) of the drawer member <NUM>. A rear end portion of the contacting and spacing member <NUM> is provided with a rack portion 42a as a driving force receiving portion for receiving the driving force for the movement of the contacting and spacing member <NUM> from the driving gear <NUM> (<FIG>).

The contacting and spacing member <NUM> is provided with a projection-recess configuration (first projection (force applying portion) 42b, second projection (force applying portion) 42c, and recess 42d) along the longitudinal direction thereof. The first projection (force applying portion) 42b of the contacting and spacing member <NUM> has a function of spacing the photosensitive drum <NUM> from the transfer belt <NUM>. The second projection (force applying portion) 42c further projects beyond a first projection 42b, and has the function of spacing the developing roller <NUM> from the photosensitive drum <NUM>. The details thereof will be described hereinafter. The recess 42d recessed from the projections is provided between the first projection 42b and the second projection 42c.

As has been described in the foregoing, the drawer unit U1 comprises the drawer member <NUM> and the contacting and spacing member <NUM>.

Referring to <FIG>, the description will be made as to the process cartridge P mounted to the drawer member <NUM>. <FIG> is a schematic sectional view of the process cartridge according to Embodiment <NUM> of the present invention. <FIG> is a perspective view of the process cartridge according to Embodiment <NUM> of the present invention. <FIG> is a perspective view illustrating the state that the process cartridge according to Embodiment <NUM> of the present invention is mounted to the drawer unit (drawer member).

The process cartridge P comprises a photosensitive member unit <NUM> and developing unit <NUM>. The photosensitive member unit <NUM> comprises the photosensitive drum <NUM>, charging means <NUM>, cleaning means <NUM>, and a residual toner container <NUM> for containing the toner removed by the cleaning means <NUM>. The developing unit <NUM> comprises the developing roller <NUM>, a toner supplying roller <NUM>, a developing blade <NUM>, and the toner container <NUM> which contains the toner used for the image formation.

As has been described hereinbefore, the toner in the toner container <NUM> is fed to the toner supplying roller <NUM>. By the toner supplying roller <NUM> and the developing blade <NUM> press-contacted to the outer periphery of the developing roller <NUM>, the toner is applied to the outer periphery of the developing roller <NUM>, and the charge is applied to the toner. By applying the developing bias from the main assembly to the developing roller <NUM>, the toner is deposited onto the latent image formed on the photosensitive drum <NUM> to form the toner image. The toner image developed on the photosensitive drum <NUM> is transferred onto the sheet material S, and thereafter the toner which remains on the photosensitive drum <NUM> surface is removed by the cleaning means <NUM> and is accommodated in the residual toner container <NUM>.

Here, when the toner in the toner container <NUM> is consumed up, the user exchanges process cartridge P, by which the user can carry out the printing again.

As shown in <FIG>, the one-end portion of the process cartridge P supports a coupling member <NUM> for receiving the driving force from the drum coupling member <NUM> of the main assembly side rotatably. It also supports a coupling member <NUM> for receiving the driving force from the development coupling member <NUM> rotatably.

The coupling member <NUM> is provided at the end of the photosensitive drum <NUM>, and the photosensitive drum <NUM> is rotated by the driving force received by the coupling member <NUM> from the main assembly. The driving force received by the coupling member <NUM> is transmitted to the developing roller <NUM> and the toner supplying roller <NUM> through an unshown intermediate gear to rotate them.

The outer periphery of the coupling member <NUM> is covered by a cylindrical rib and constitutes an engaging portion 71a. The engaging portion 71a is provided on a side cover <NUM> fixed to the outside of the toner container <NUM>. The coupling member <NUM> is rotatable relative to the engaging portion 71a. As shown in <FIG>, an engaging portion 70a is provided on the opposite side from the engaging portion 71a. This engaging portion 70a is similarly provided on a side cover <NUM>. These engaging portions 71a, 70a are provided on the developing unit <NUM>.

The residual toner container <NUM> is provided with hole portions 30a, 30b supporting the engaging portions 71a, 70a. The hole portions 30a, 30b provided in the residual toner container <NUM> engage with the engaging portions 71a, 70a provided in the developing unit <NUM>, by which the photosensitive member unit <NUM> and the developing unit <NUM> connect with each other.

Here, the engaging portions 71a, 70a are movable (rotatable) relative to the hole portions 30a, 30b respectively, and therefore, the developing unit <NUM> can be moved relative to the photosensitive member unit <NUM>. That is, the developing roller <NUM> is movable relative to the photosensitive drum <NUM>.

As shown in <FIG>, between the photosensitive member unit <NUM> and the developing unit <NUM>, a spring <NUM> as an urging member is provided. The spring <NUM> presses the developing roller <NUM> with the predetermined pressure to the photosensitive drum <NUM>. When the developing unit <NUM> moves in the direction of separating the developing roller <NUM> from the photosensitive drum <NUM> relative to the photosensitive member unit <NUM>, it moves against an urging force of the spring <NUM>.

As shown in <FIG>, the outer periphery of the coupling member <NUM> is covered by the cylindrical rib to form a portion-to-be-guided 30c. As shown in <FIG>, a portion-to-be-guided 30d in the form of a cylindrical projection is provided on the opposite side of the portion-to-be-guided 30c with respect to the longitudinal direction. As shown in <FIG>, a portion-to-be-guided 30e is provided above the portion-to-be-guided 30c, and as shown in <FIG>, a portion-to-be-guided 30f is provided above the portion-to-be-guided 30d. The portions-to-be-guided 30c, 30d, 30e, 30f has the function of the guide for the mounting, into the drawer member <NUM>, of the process cartridge P, and have a function of positioning the process cartridge P in the drawer member <NUM>. The details thereof will be described hereinafter.

As shown in <FIG>, an upper portion of one of the lateral sides of the photosensitive member unit, <NUM> is provided with an outwardly projecting force receiving portion <NUM> with respect to an axial direction of the photosensitive drum <NUM>. The force receiving portion <NUM> receives the force from the contacting and spacing member <NUM> provided in the drawer member <NUM> to space the photosensitive drum <NUM> from the transfer belt <NUM>. The details thereof will be described hereinafter. As shown in <FIG>, furthermore, an upper portion of the other side surface of the photosensitive member unit <NUM> is provided with a force receiving portion <NUM>. The force receiving portions <NUM>, <NUM> receive a force from the urging members <NUM>, <NUM> as will be described hereinafter to position the process cartridge P in the drawer member <NUM>.

As shown in <FIG>, an outwardly projecting force receiving portion, 71b with respect to the axial direction of the developing roller <NUM> is provided above the side cover <NUM> of the developing unit <NUM>. The force receiving portion 71b receives the force from the contacting and spacing member <NUM> to space the developing roller <NUM> from the photosensitive drum <NUM>. The details thereof will be described hereinafter.

Referring to <FIG>, the description will be made as to the mounting of process cartridges P (Py, Pm, Pc, Pk) to the drawer member <NUM>. The <FIG> and <FIG> are the perspective views illustrating the state that the process cartridge according to Embodiment <NUM> of the present invention is mounted to the drawer member. The <FIG> and <FIG> show the mounting process of the process cartridge and are views, as seen from different directions. In <FIG>, all the process cartridges are mounted. <FIG> is a schematic view showing the state that the process cartridge is mounted to the drawer member. <FIG> is a side view, and <FIG> is a schematic longitudinal sectional view.

The process cartridges Py, Pm, Pc, Pk are mounted into the four mounting portions 13f (<FIG>) provided in the drawer member <NUM>, respectively. The user mounts the process cartridge P in a direction of the arrow C which is substantially the direction of gravity.

In mounting the process cartridge P, first, the user moves it, so that the portions-to-be-guided 30c, 30d provided at the opposite ends of the process cartridge P are guided by the guide portions <NUM>, 13j of the drawer member <NUM>. Then, the user moves it, so that the portions-to-be-guided 30e, 30f are guided by the guides 13i, <NUM>. By this, the process cartridge P is mounted to the inside of the drawer member <NUM>, while being guided by the guide portions <NUM>, 13i, 13j and <NUM>.

In the process in which the process cartridge P is mounted to the drawer member <NUM>, the force receiving portion <NUM> provided on the photosensitive member unit <NUM> abuts to the first projection (force applying portion) 42b provided on the contacting and spacing member <NUM>. The force receiving portion 71b provided on the side cover <NUM> of the developing unit <NUM> abuts to the second projection (force applying portion) 42c.

The force receiving portion <NUM> provided on the photosensitive member unit <NUM> abuts to the first projection 42b, by which the process cartridge P is held in a position higher than the image forming position. As shown in <FIG>, that is, the surface of the photosensitive drum <NUM> is held in the (spacing) position higher than the surface (recording material conveying surface) of the transfer belt <NUM>.

Here, the contacting and spacing member <NUM> is provided only at one-end portion of the drawer member <NUM>. The force receiving portion <NUM> for receiving the force from the first projection 42b of the contacting and spacing member <NUM> is also provided only at the one side of the photosensitive member unit <NUM>. However, the portion-to-be-guided 30d provided at the other end portion of the process cartridge P is provided in the outside of the widthwise end of the transfer belt <NUM>, and therefore, the surface of the photosensitive drum <NUM> can be separated from the surface of the transfer belt <NUM>. That is, as for the process cartridge P, the force receiving portion <NUM> receives the force from first projection 42b in the one-end portion to rise. On the other hand, the state that the portion-to-be-guided 30d is in contact to a positioning portion 13j1 of the drawer member <NUM> is maintained in the other end portion. For this reason, the process cartridge P is oblique relative to the transfer belt <NUM>. However, as has been described hereinbefore, the portion-to-be-guided 30d is provided to the outside of the widthwise end of the transfer belt <NUM>, and therefore, the surface of the photosensitive drum <NUM> is spaced from the surface of the transfer belt <NUM>.

By the force receiving portion 71b provided on the developing unit <NUM> contacting to the second projection 42c provided on the contacting and spacing member <NUM>, the surface of the developing roller <NUM> is spaced from the surface of the photosensitive drum <NUM>. Referring mainly to <FIG>, the description will be made.

The second projection 42c provided on the contacting and spacing member <NUM> is higher than the first projection 42b. On the other hand, the force receiving portion <NUM> provided on the photosensitive member unit <NUM> and the force receiving portion 71b provided on the developing unit are substantially at the same level in the state of not receiving an external force. Therefore, the force receiving portion 71b abutted to the second projection 42c receives the weight of the developing unit <NUM> to space the surface of the developing roller <NUM> from the surface of the photosensitive drum <NUM> against the force of the urging member <NUM>. That is, by the force receiving portion 71b receiving the force, the engaging portions 71a, 70a provided on the developing unit <NUM> rotates about the hole portions 30a, 30b provided in the photosensitive member unit <NUM>, respectively.

At this time, the contacting and spacing member <NUM> is in such a position that the first projection 42b contacts to the force receiving portion <NUM>, and the second projection 42c contacts to the force receiving portion 71b. At this time, the surface of the developing roller <NUM> can be placed in the position spaced from the surface of the photosensitive drum <NUM>. This position is a spacing position, wherein the contacting and spacing member <NUM> can isolate the photosensitive drum <NUM> from the transfer belt <NUM>, and can space the developing roller <NUM> from the photosensitive drum <NUM>.

In the case where the drawer member <NUM> is in the state of being drawn from the main assembly, that is, in the case where the drawer member <NUM> is positioned in the outside of the main assembly (outside position), the contacting and spacing member <NUM> is placed in the spacing position. As shown in <FIG>, for this reason, when the process cartridge P is mounted to the drawer member <NUM>, the surface of the developing roller <NUM> is spaced from the surface of the photosensitive drum <NUM> together with the mounting operation. Therefore, in mounting the process cartridge P to the drawer member <NUM> it can be avoided that the surface of the photosensitive drum <NUM> and the surface of the developing roller <NUM> are rubbed with each other by the impact at the time of the mounting, and these surfaces are damaged.

As has been described in the foregoing, in mounting the process cartridge P to the drawer member <NUM>, the state that the surface of the developing roller <NUM> is spaced from the surface of the photosensitive drum <NUM> is maintained. In addition, the state that the surface of the photosensitive drum <NUM> is spaced from the surface of the transfer belt <NUM> is maintained.

Referring to <FIG> the description will be made as to the mounting operation of the drawer unit U1 into the main assembly. <FIG> is a perspective view illustrating the state that the drawer unit according to Embodiment <NUM> of the present invention is mounted to the inside of the main assembly. <FIG> is a schematic sectional view illustrating the state that the drawer unit according to Embodiment <NUM> of the present invention is mounted to the inside of the main assembly. <FIG> is a schematic sectional view illustrating the state that the drawer unit according to Embodiment <NUM> of the present invention is mounted to the inside of the main assembly, and the door is open. <FIG> and <FIG> include the enlarged cross-sectional views of the schematic sectional views of the whole device and the neighborhood of the one photosensitive drum. <FIG> is a schematic sectional view illustrating the state that the drawer unit according to Embodiment <NUM> of the present invention is mounted to the inside of the main assembly, and the door closes. <FIG>, the state that the image forming operation is not carried out is shown.

As shown in <FIG>, the drawer unit U1 is mounted in a direction of arrow E while the portions-to-be-guided 13a, 13b, 13c, and 13d (<FIG>, <FIG>) of the drawer member <NUM> is guided by the guide portions 14R and <NUM> of the main assembly (<FIG>).

During the mounting operation of the drawer unit U1 (drawer member <NUM>), the state that the surface of the photosensitive drum <NUM> and a recording material conveying surface 11a of the transfer belt <NUM> are spaced from each other are maintained. That is, a gap g is provided between the surface of the photosensitive drum <NUM> and the recording material conveying surface 11a of the transfer belt <NUM>. Therefore, the drawer unit U1 can be mounted to the inside of the main assembly without the rubbing between the surface of the photosensitive drum <NUM> and the surface of the transfer belt <NUM>. During the mounting operation, the drawer unit U1 is moved in substantially parallel with the recording material conveying surface 11a of the transfer belt <NUM>.

As has been described hereinbefore, during the mounting operation of the drawer unit U1, the separation member <NUM> is placed in the spacing position, the state of spacing the surface of the photosensitive drum <NUM> and the developing roller <NUM> from each other is maintained. That is, a gap h is provided between them. Therefore, in mounting the drawer unit U1 which carries the process cartridge P to the inside of the main assembly, the damage due to the contact between the surface of the photosensitive drum <NUM> and the surface of the developing roller <NUM> by the impact at the time of the mounting or the like is suppressed.

When the drawer unit U1 is mounted to the inside of the main assembly, the rack portion 42a (<FIG>) provided on the contacting and spacing member <NUM> and the driving gear <NUM> of the main assembly (<FIG>) engage with each other. By this, the driving force is transmittable to the rack portion 42a from the driving gear <NUM>.

As shown in <FIG>, in the state that the drawer unit U1 is completely inserted into the main assembly, and the door <NUM> is open, the surface of the photosensitive drum <NUM> and the recording material conveying surface 11a of the transfer belt <NUM> are still spaced from each other. The surfaces of the photosensitive drum <NUM> and the developing roller <NUM> are spaced from each other similarly.

In the state of <FIG>, the door is closed. By the closing operation of the door <NUM>, the drum coupling member <NUM> and the development coupling member <NUM> (<FIG>) enter the opening portion <NUM> and <NUM> of the opening portion (<FIG>) provided in the drawer member <NUM>, respectively. However, the process cartridge P is not placed in a regular position (the operative position for the image formation) as yet. Therefore, the drum coupling member <NUM> and the development coupling member <NUM> are not in engagement with the coupling members <NUM> and <NUM> (<FIG>).

Also in the state where the door <NUM> is closed, when the image forming operation is not carried out, the spaced state is maintained between the surface of the photosensitive drum <NUM> and the recording material conveying surface 11a of the transfer belt <NUM>, and between the surface of the photosensitive drum <NUM> and the surface of the developing roller <NUM>. That is, the contacting and spacing member <NUM> is placed in the spacing position.

In such a state, apparatus is maintained until the instruction of the image forming operation is produced from the main assembly.

Referring to <FIG> the description will be made as to the operation of each part at the time of the image forming operation. <FIG> is a perspective view illustrating the state immediately after the image formation instruction in the drawer unit according to Embodiment <NUM> of the present invention. <FIG> is a schematic sectional view illustrating the state in which the drawer unit according to Embodiment <NUM> of the present invention is mounted to the inside of the main assembly, and in which it is of partway of shifting to the image forming operation. <FIG> includes a schematic sectional view of the neighborhood of the drawer unit and the transfer belt and an enlarged cross-sectional view of the neighborhood of the one photosensitive drum. <FIG> is a perspective view illustrating the state of the partway of shifting to the image forming operation in the drawer unit according to Embodiment <NUM> of the present invention. <FIG> is a schematic sectional view illustrating the state of the partway of shifting to the image forming operation in the image forming apparatus according to Embodiment <NUM> of the present invention. <FIG> includes a schematic sectional view of the whole device and an enlarged cross-sectional view of the neighborhood of the one photosensitive drum. <FIG> is a perspective view illustrating the state in the course of shifting to the image forming operation in the drawer unit according to Embodiment <NUM> of the present invention. <FIG> is a schematic sectional view illustrating the state that the image forming operation is capable in the image forming apparatus according to Embodiment <NUM> of the present invention. <FIG> includes an enlarged cross-sectional view of a schematic sectional view of the whole device and the neighborhood of one photosensitive drum.

The instruction of the image formation is produced, the driving gear <NUM> connected operatively with a motor (unshown) provided in the main assembly is rotated in a direction of arrow F in <FIG>. By this, the contacting and spacing member <NUM> is moved in the direction of arrow G in the Figure by the rack portion 42a engaged with the driving gear <NUM>. When the contacting and spacing member <NUM> move to the position shown in <FIG>, the force receiving portion <NUM> provided on the photosensitive member unit <NUM> separates from the first projection 42b of the contacting and spacing member <NUM>. However, the force receiving portion 71b provided in the developing unit <NUM> is still placed on the second projection 42c. Since the second projection 42c is longer than the first projection 42b, such a mechanism is established in the movement direction of the contacting and spacing member <NUM>.

<FIG> shows a positional relation among the drawer member <NUM>, the process cartridge P, and the transfer belt <NUM> in the state shown in <FIG>. As has been described hereinbefore, the force receiving portion <NUM> separates from the first projection 42b by a moving operation of the contacting and spacing member <NUM>, by which the surface of the photosensitive drum <NUM> is contacted to the surface of the transfer belt <NUM>. On the other hand, the force receiving portion 71b is maintained in the state of receiving the force from the second projection 42c, and therefore, the developing roller <NUM> is spaced from the surface of the photosensitive drum <NUM>. Here, the space is maintained between the surface of the photosensitive drum <NUM> and the surface of the developing roller <NUM>, and therefore, the contacting and spacing member <NUM> takes the spacing position.

As shown in <FIG>, thereafter, the urging members <NUM>, <NUM> provided in the main assembly side are driven with the unshown driving source and moves in a direction of arrow H. The urging members <NUM>, <NUM> abut to the force receiving portions <NUM>, <NUM> provided on the process cartridge P and apply the force to it. By this, the portion-to-be-guided 30c (<FIG>) of the process cartridge P abuts to the positioning portion 13h1 (<FIG>) provided on the drawer member <NUM>. The portion-to-be-guided 30d (<FIG>) abuts to the positioning portion 13j1 (<FIG>). Furthermore, the portions-to-be-guided 30e and 30f (<FIG>, <FIG>) engage with the guide portions 13i and <NUM> (<FIG>, <FIG>), and the process cartridge P is positioned in the drawer member <NUM>.

As has been described in the foregoing, by the function of the urging members <NUM>, <NUM>, the process cartridge P is positioned in the main assembly.

<FIG> shows the inside a main assembly in the state shown in <FIG>. In the process cartridge P in this state, the surface of the developing roller <NUM> is spaced from the surface of the photosensitive drum <NUM>. The surface of the photosensitive drum <NUM> is kept spaced from the surface of the transfer belt <NUM>. That is, the position of the contacting and spacing member <NUM> at this time corresponds to the spacing position.

As shown in <FIG>, thereafter, in order to contact the developing roller <NUM> and the photosensitive drum <NUM> relative to each other, the driving gear <NUM> further rotates and moves the contacting and spacing member <NUM> in a direction of arrow G. By this, the force receiving portion 71b provided on the developing unit <NUM> separates from the second projection 42c of the contacting and spacing member <NUM> and does not receive the force from the second projection 42c. Therefore, the surface of the developing roller <NUM> and the surface of the photosensitive drum <NUM> contact to each other by the urging force of the spring <NUM> provided between the developing unit <NUM> and the photosensitive member unit <NUM>. By this, as for the image forming apparatus <NUM>, the image formation is enabled. This position is a contacting position, wherein the contacting and spacing member <NUM> contacts the developing roller <NUM> to the photosensitive drum <NUM> to enable the image formation. The image forming operation is as has been described hereinbefore. <FIG> shows the inside of the main assembly at the time of being in the state that the image forming operation is capable.

When the image formation finishes, the driving gear <NUM> is rotated in the direction opposite the direction of arrow F shown in <FIG> to move the contacting and spacing member <NUM> in the direction of arrow I in <FIG>. By this, the contacting and spacing member <NUM> is moved to the spacing position, and spaces the surface of the developing roller <NUM> from the surface of the photosensitive drum <NUM> (<FIG>, <FIG>).

Thereafter, the urging members <NUM>, <NUM> carry out in movement in the direction opposite the above described pressing direction, and the contacting and spacing member <NUM> further moves in a direction of arrow I. By this, the surface of the photosensitive drum <NUM> is spaced from the surface of the transfer belt <NUM>. In this state, the apparatus waits for the instruction of the next image formation. Or, in the case where the drawer member <NUM> is drawn, the state is maintained in which the surface of the photosensitive drum <NUM> and the surface (recording material conveying surface 11a) of the transfer belt <NUM> are spaced from each other and the surface of the photosensitive drum <NUM> and the surface of the developing roller <NUM> are spaced from each other. That is, the contacting and spacing member <NUM> is placed in the spacing position. Therefore, when the drawer member <NUM> which carries the process cartridge P is drawn from the main assembly, the damage due to the contact between the surface of the photosensitive drum <NUM> and the surface of the developing roller <NUM> by the impact at the time of the movement or the like is suppressed.

As has been described in the foregoing, according to the image forming apparatus <NUM> of this embodiment, the contacting and spacing member is movable between the spacing position and the contacting position And, by the movement of the contact member <NUM>, the developing roller <NUM> moves timely to the position of spacing from the photosensitive drum <NUM> or the position of contacting to the photosensitive drum <NUM>. By this, the state of the developing roller <NUM> not contacting to the photosensitive drum <NUM> can be established, when the image forming operation is not carried out, namely, during drawing the drawing unit U1 (drawer member <NUM>) outwardly, and so on. Therefore, the deteriorations of various members can be suppressed, and the service lives can be extended.

In addition, the image forming apparatus <NUM> according to this embodiment employs a structure in which the drawer member <NUM> is provided with the contacting and spacing member <NUM>. Therefore, the structure for advancing the contacting and spacing member from the main assembly side of the apparatus into the drawer member is not necessitated unlike in the conventional example in which the contacting and spacing member for spacing the developing roller from the photosensitive drum is provided in the main assembly side of the apparatus. In other words, no space is required to move the contacting and spacing member from the main assembly side of the apparatus to the position of the cartridge in the drawer member, and therefore, the main assembly of the apparatus can be downsized.

It would be considered that the contacting and spacing member is fixed to the main assembly side of the apparatus, and a force receiving portion of the drawer member provided in the cartridge receives a force from the contacting and spacing member by a pushing-in operation and a drawing operation to contact and space the developing roller relative to the photosensitive drum.

However, even when such a structure is employed, it is necessary to project the force receiving portion out of the drawer member in order to make the force receiving portion of the cartridge contactable to the contacting and spacing member. Therefore, the apparatus is not downsized enough. According to this embodiment, however, the contacting and spacing member <NUM> is provided in the drawer member <NUM>, and therefore, it is unnecessary to project the force receiving portion 71b too much, and the process cartridge P can be downsized.

Even when such structures are employed, the cartridge has to be mounted in the state that the force receiving portion of the cartridge is retracted from the contacting and spacing member, in order to contact the force receiving portion of the cartridge to the contacting and spacing member at the desired timing. And, the result is that the structure or mechanism is required to move the entire drawer member to the position where the force receiving portion of the cartridge contacts to the contacting and spacing member. According to this embodiment, however, the contacting and spacing member <NUM> is provided in the drawer member <NUM>, and therefore, the structure of the main assembly of the apparatus can be simplified and downsized.

In this embodiment, as for the example of the transfer belt <NUM>, the sheet material S which is the transfer member is fed to the surface of the photosensitive drum <NUM>, and the developer image on the photosensitive drum <NUM> is directly transferred onto the sheet material S. However, the present invention is applicable also to the image forming apparatus, wherein the transfer belt receives the developer image formed on the photosensitive drum and, finally the image is transferred onto the recording material (sheet material) (intermediary transfer belt type).

In this embodiment, the contacting and spacing member <NUM> is provided only at the one-end portion of the drawer member <NUM>. However, a contacting and spacing member may also be provided like the other end portion of the drawer member <NUM>. In this case, the force receiving portion for receiving the force from the contacting and spacing member is also provided in the other end portion. If the contacting and spacing member is provided at the respective sides, the shafts of the photosensitive drum and the developing roller in the process cartridge do not incline during the movement thereof. Therefore, the spaced state between the photosensitive drum and the transfer belt and the spaced state between the photosensitive drum and the developing roller can further be stabilized.

<FIG> illustrates the various parts by Embodiment <NUM> of the present invention. In Embodiment <NUM>, the process cartridge P which contains the photosensitive member unit <NUM> which includes the photosensitive drum <NUM> and the developing unit <NUM> which includes the developing roller <NUM> integrally is mounted to the drawer member <NUM>. In this embodiment, a photosensitive member unit which includes the photosensitive drum <NUM> and the developing unit which includes the developing roller <NUM> are mounted individually to a drawer member <NUM>. The like reference numerals as in the foregoing embodiment are assigned to the elements having the corresponding functions.

Referring to <FIG>, the description will be made as to the developing cartridge which is the developing unit according to Embodiment <NUM> of the present invention. <FIG> is a perspective view of the developing cartridge according to Embodiment <NUM> of the present invention. In <FIG>, they are perspective views, as seen from the different directions ((a) and (b)).

A developing cartridge <NUM> according to this embodiment comprises the developing roller <NUM>, a toner supplying roller (unshown), a developing blade (unshown), and a toner container <NUM> which contains the toner which is the developer used for the image formation. In the image forming apparatus according to this embodiment, the four developing cartridge s <NUM> which contain the toner of the different color are used. The reference numerals for these cartridges are 60y, <NUM>, 60c, and <NUM> but the reference numerals maybe simply "<NUM>" if no confusion arises. Here, y means the yellow, m means the magenta, c means the cyan, and k means the black.

As shown in <FIG>, the one-end portion of the developing cartridge <NUM> rotatably supports the coupling member <NUM> for receiving the driving force from the development coupling member <NUM> of the main assembly side. The driving force received by the coupling member <NUM> is transmitted to the developing roller <NUM>, the toner supplying roller, and so on through the unshown intermediate gear.

The upper portion of the side cover, <NUM> of one side of the developing cartridge <NUM> is provided with an outwardly projecting force receiving portion 61a with respect to the axial direction which is the developing roller <NUM>. This force receiving portion 61a receives the force from the contacting and spacing member <NUM> (<FIG>) to space the developing roller <NUM> from the photosensitive drum <NUM>. The details thereof will be described hereinafter. Furthermore, the upper portion of a side cover <NUM> of the another side of the developing cartridge <NUM> is provided with a force receiving portion 62a. The force receiving portions 61a, 62a is pressed by the urging members provided in the main assembly to position the developing cartridge <NUM> relative to the drawer member <NUM>. The details thereof will be described hereinafter.

Adjacent to the force receiving portions, 61a, 62a, a portions to be positioned 61b, 62b are provided, and they outwardly project with respect to the axial direction which is the developing roller <NUM>. The details thereof will be described hereinafter.

Referring to <FIG> the description will be made as to the photosensitive member cartridge which is the photosensitive member unit according to Embodiment <NUM> of the present invention. <FIG> is a perspective view of the photosensitive member cartridge according to Embodiment <NUM> of the present invention. In <FIG>, they are the perspective views, as seen from the different directions ((a) and (b)).

A photosensitive member cartridge <NUM> according to this embodiment comprises the photosensitive drum <NUM>, the charging means <NUM>, the cleaning means (unshown), and a residual toner container <NUM> for containing the toner removed by the cleaning means. As for the image forming apparatus according to this embodiment, the four photosensitive member cartridge s <NUM> which contain the toner of the different color are used. The reference numerals for these cartridges are 50y, <NUM>, 50c, and <NUM> but the reference numerals maybe simply <NUM> if no confusion arises, although y means yellow, m means magenta, c means cyan, and k means black.

As shown in <FIG>, one-end portion of the photosensitive member cartridge <NUM> supports the coupling member <NUM> for receiving the driving force from the drum coupling member <NUM> of the main assembly side rotatably. The coupling member <NUM> is provided at the end of the photosensitive drum <NUM>, and the photosensitive drum <NUM> rotates by the driving force received by the coupling member <NUM> from the main assembly side.

An outer periphery of the coupling member <NUM> is covered by the cylindrical rib to constitute a portion-to-be-guided 31a. On the opposite side of the portion-to-be-guided 31a, a portion-to-be-guided 31b which is provided with the cylindrical projection is provided. Above the portion-to-be-guided 31a, a portion-to-be-guided 31c is provided, and above the portion-to-be-guided 31b, a portion-to-be-guided 31d is provided. The portions-to-be-guided 31a, 31b, 31c, 31d has the guiding function, when the photosensitive member cartridge <NUM> is mounted into the drawer member <NUM> and when it is positioned in the drawer member <NUM>. The details thereof will be described hereinafter.

One of the upper portions of the ends of the photosensitive member cartridge, <NUM> is provided with a force receiving portion 31e outwardly projected with respect to the axial direction from the photosensitive drum <NUM>. The force receiving portion 31e receives the force from the contacting and spacing member <NUM> (<FIG>) provided in the drawer member <NUM> to space the photosensitive drum <NUM> from the transfer belt <NUM>. The details thereof will be described hereinafter. Furthermore, the other end of the photosensitive member cartridge <NUM> is provided with a force receiving portion 31f. The force receiving portions 31e, 31f is pressed by the urging members provided in the main assembly, to position the photosensitive member cartridge <NUM> relative to the drawer member <NUM>. The details thereof will be described hereinafter.

Referring to <FIG> the description will be made as to the drawer member <NUM> according to Embodiment <NUM> of the present invention. The <FIG> are the perspective views of the drawer unit in the image forming apparatus according to Embodiment <NUM> of the present invention. The <FIG> are the perspective views, as seen from the different directions.

The drawer unit U2 according to this embodiment is different from Embodiment <NUM> in that the drawer member <NUM> is provided with the positioning portions 63a, 63b in order to position the developing cartridge <NUM> in the drawer member <NUM>.

The developing cartridge <NUM> is positioned in the drawer member <NUM> by the portions to be positioned 61b and 62b (<FIG>) engaging with the positioning portions 63a, 63b provided in the drawer member <NUM>.

Similarly to Embodiment <NUM>, the drawer member <NUM> is provided with the contacting and spacing member <NUM>. Since the structure of the contacting and spacing member <NUM> is similar to Embodiment <NUM>, the description is omitted for the sake of simplicity. In addition, similarly to Embodiment <NUM>, the drawer unit U2 comprises the drawer member <NUM> and the contacting and spacing member <NUM>.

Referring to <FIG> and <FIG> the description will be made as to the mounting of the developing cartridge s <NUM> (60y, <NUM>, 60c, <NUM>) and the photosensitive member cartridges <NUM> (50y, <NUM>, 50c, <NUM>) to the drawer member <NUM>. The <FIG> and <FIG> are the perspective views illustrating the state of mounting the photosensitive member cartridge and the developing cartridge according to Embodiment <NUM> of the present invention to the drawer member. The <FIG> and <FIG> illustrate the state of the process of the mounting of the cartridge and are views, as seen from the different directions.

In this embodiment, the photosensitive member cartridge <NUM> and the developing cartridge <NUM> are mounted individually into the drawer member <NUM>. In the case of mounting them to the drawer member <NUM>, the photosensitive member cartridge <NUM> is mounted, and thereafter the developing cartridge <NUM> is mounted.

In the case of mounting the photosensitive member cartridge <NUM>, it is mounted by the user while the portions-to-be-guided 31a, 31b provided at the opposite ends of the photosensitive member cartridge <NUM> are guided to the guide portions 63c, 63d of the drawer member <NUM>. Then, it is mounted while the portions-to-be-guided 31c, 31d are guided by the guide portions 63e, 63f. By this, the photosensitive member cartridge <NUM> is mounted to the inside of the drawer member <NUM>.

In the case of mounting the developing cartridge <NUM>, the user mounts the developing cartridge <NUM>, so that the portions to be positioned 61b, 62b of the developing cartridge <NUM> aligns with the positioning portions 63a, 63b provided in the drawer member <NUM>. However, the portions to be positioned 61b, 62b are not contacted to the positioning portions 63a, 63b at the time mounting.

In the process in which the photosensitive member cartridge <NUM> is mounted to the drawer member <NUM>, the force receiving portion 31e provided on the photosensitive member cartridge <NUM> contacts to the first projection (force applying portion) 42b (<FIG>) provided on the contacting and spacing member <NUM>. The force receiving portion 61a provided on the side cover <NUM> of the developing cartridge <NUM> contacts to the second projection (force applying portion) 42c (<FIG>).

By the force receiving portion 31e provided on the photosensitive member cartridge <NUM> contacting to the first projection 42b, the photosensitive member cartridge <NUM> is held at the position higher than the image forming position. That is, the surface of the photosensitive drum <NUM> is held at the position (spaced position) higher than the surface (recording material conveying surface 11a) of the transfer belt <NUM>.

By the force receiving portion 61a provided on the developing cartridge <NUM> contacting to the second projection 42c provided on the contacting and spacing member <NUM>, the surface of the developing roller <NUM> is spaced from the surface of the photosensitive drum <NUM>. As to this, the description will be made referring to <FIG> is a schematic sectional view illustrating the state that the drawer unit according to Embodiment <NUM> of the present invention is mounted into the main assembly. In <FIG>, a schematic sectional view of the whole device and a schematic enlarged cross-sectional view of a photosensitive drum neighborhood are shown.

The second projection 42c provided on the contacting and spacing member <NUM> is disposed at the position higher than the first projection 42b. On the other hand, the force receiving portion 31e provided in the photosensitive member cartridge <NUM> and the force receiving portion 61a provided in the developing cartridge <NUM> are substantially at the same heights in the state of not receiving the external force. By this, the developing cartridge <NUM> is held at the position higher than the photosensitive member cartridge <NUM>. Therefore, the surface of the developing roller <NUM> is separated from the surface of the photosensitive drum <NUM>.

Here, the contacting and spacing member <NUM> is provided only at the one-end portion of the drawer member <NUM>. The force receiving portion 61a for receiving the force from the second projection 42c of the contacting and spacing member <NUM> is also provided only on the one side of the developing cartridge <NUM>. However, since the portion to be positioned, 62b provided at the other end portion of the developing cartridge, <NUM> is outwardly provided beyond the end with respect to the longitudinal direction of the photosensitive drum <NUM>, the surface of the developing roller <NUM>, can be separated from the surface of the photosensitive drum <NUM>. That is, the force receiving portion 61a receives the force from the second projection 42c, so that the developing cartridge <NUM> rises at the one-end portion. On the other hand, in the other end portion, the portion to be positioned 62b is in contact to a positioning portion 63b of the drawer member <NUM>. For this reason, the developing cartridge <NUM> is oblique relative to the photosensitive drum <NUM>. However, as has been described hereinbefore, since the portion to be positioned 62b is outwardly provided beyond the longitudinal end of the photosensitive drum <NUM>, the surface of the developing roller <NUM> is spaced from the surface of the photosensitive drum <NUM>.

In this manner, when the photosensitive member cartridge <NUM> and the developing cartridge <NUM> are mounted, the contacting and spacing member <NUM> is in such a position that the first projection 42b contacts to the force receiving portion 31e, and the second projection 42c contacts to the force receiving portion 61a. At this time, the surface of the photosensitive drum <NUM> can be placed in the position spaced from the surface of the transfer belt <NUM>. The surface of the developing roller <NUM> can be placed in the position spaced from the surface of the photosensitive drum <NUM>. Similarly to Embodiment <NUM>, such a position that the contacting and spacing member <NUM> spaces the developing roller <NUM> from the photosensitive drum <NUM>, is a spacing position.

In this manner, in the process in which the developing cartridge <NUM> is mounted to the drawer member <NUM>, in the state that the surface of the developing roller <NUM> is spaced from the surface of the photosensitive drum <NUM>, the developing cartridge <NUM> is mounted. Therefore, in mounting the developing cartridge <NUM> to the drawer member <NUM> the surface damage due to the rubbing between the surface of the photosensitive drum <NUM> and the surface of the developing roller <NUM> by the impact at the time of the mounting can be suppressed.

As has been described in the foregoing, the photosensitive member cartridge <NUM> and the developing cartridge <NUM> are mounted to the drawer member <NUM> while spacing is established between the surface of the developing roller <NUM> and the surface of the photosensitive drum <NUM> and between the surface of the photosensitive drum <NUM> and the surface of the transfer belt <NUM>.

Referring to <FIG>, the description will be made as to the mounting operation of the drawer unit U2 into the main assembly. <FIG> is a schematic sectional view illustrating the state that the drawer unit according to Embodiment <NUM> of the present invention is mounted to the inside of the main assembly. <FIG> is a schematic sectional view illustrating the state which the drawer unit according to Embodiment <NUM> of the present invention is mounted to the inside of the main assembly, and the door opens. <FIG> and <FIG> include a schematic sectional view of the whole device and a schematic enlarged cross-sectional view of the neighborhood of one photosensitive drum are shown. <FIG> is a schematic sectional view illustrating the state that the drawer unit according to Embodiment <NUM> of the present invention is mounted to the inside of the main assembly, and the door closes. In <FIG>, the image forming operation is not carried out.

As shown in <FIG>, the drawer unit U2 (drawer member <NUM>) is mounted to the inside of the main assembly in a direction of the arrow D1. During the mounting operation of the drawer unit U2, the surface of the photosensitive drum <NUM> and the recording material conveying surface 11a of the transfer belt <NUM> are spaced from each other. That is, a gap g is provided between the surface of the photosensitive drum <NUM> and the recording material conveying surface 11a of the transfer belt <NUM>. Therefore, the drawer unit U2 can be mounted to the inside of the main assembly without the surface of the photosensitive drum <NUM> rubbing with the surface of the transfer belt <NUM>.

During the mounting operation of the drawer unit U2, the contacting and spacing member <NUM> is placed in the spacing position, and the surfaces of the photosensitive drum <NUM> and the developing roller <NUM> is also spaced from each other. That is, the gap h is provided therebetween. Therefore, in mounting the drawer unit U2 to the inside of the main assembly, the damage due to the contact between the surface of the photosensitive drum <NUM> and the surface of the developing roller <NUM> by the impact at the time of the mounting and so on can be suppressed.

As shown in <FIG>, in the state that the drawer unit U2 is completely inserted into the main assembly, and the door <NUM> is open, the surface of the photosensitive drum <NUM> and the recording material conveying surface 11a of the transfer belt <NUM> are still spaced from each other. The surfaces of the photosensitive drum <NUM> and the developing roller <NUM> are also spaced from each other.

<FIG> shows the state where the door is closed. , even if the door <NUM> is in the closed state, when the image forming operation is not carried out, the space is kept between the surface of the photosensitive drum <NUM> and the recording material conveying surface 11a of the transfer belt <NUM> and between the surface of the photosensitive drum <NUM> and the surface of the developing roller <NUM> That is, the contacting and spacing member <NUM> is placed in the spacing position.

In the state as described above, the device waits for the instruction of the image forming operation from the main assembly.

Referring to <FIG>, the description will be made as to the operation of each part at the time of the image forming operation. <FIG> is a perspective view illustrating the state immediately after the image formation instruction in the drawer unit according to Embodiment <NUM> of the present invention. <FIG> is a schematic sectional view illustrating the state in the course of the drawer unit according to Embodiment <NUM> of the present invention being mounted to the inside of the main assembly, and shifting to the image forming operation. <FIG> includes a schematic sectional view of the whole device and a schematic enlarged cross-sectional view of the neighborhood of the one photosensitive drum. <FIG> is a schematic sectional view illustrating the state in the course of shifting to the image forming operation in the image forming apparatus according to Embodiment <NUM> of the present invention. <FIG> is a schematic sectional view illustrating the state in the course of shifting to the image forming operation in the image forming apparatus according to Embodiment <NUM> of the present invention. <FIG> includes a schematic sectional view of the whole device and a schematic enlarged cross-sectional view of the neighborhood the one photosensitive drum. <FIG> is a schematic sectional view illustrating the state that the image forming operation is enabled in the image forming apparatus according to Embodiment <NUM> of the present invention. <FIG> includes a schematic sectional view of the whole device and a schematic enlarged cross-sectional view of the neighborhood of the one photosensitive drum.

When the instruction of the image formation is produced, the driving gear <NUM> connected operatively with the motor (unshown) provided in the main assembly rotate in the direction of arrow F as shown in <FIG>,. Therefore, by the rack portion 42a in engagement with the driving gear <NUM>, the contacting and spacing member <NUM> is moved in the direction of arrow G in the Figure. When the contacting and spacing member <NUM> moves to the position shown in <FIG>, the force receiving portion 31e provided on the photosensitive member cartridge <NUM> separates from the first projection 42b of the contacting and spacing member <NUM>. However, the force receiving portion 61a provided on the developing cartridge <NUM> is still placed on the second projection 42c. Such a mechanism is established because the second projection 42c is longer than the first projection 42b with respect to the movement direction of the contacting and spacing member <NUM>.

<FIG> shows a schematic sectional view of the entirety of the device in the state of <FIG>. As has been described hereinbefore, the force receiving portion 31e separates from the first projection 42b by the moving operation of a contacting and spacing member <NUM>, by which the surface of the photosensitive drum <NUM> is contacted to the surface of the transfer belt <NUM>. On the other hand, the force receiving portion 61a is still in the state of keeping receiving the force from the second projection 42c, and therefore, the developing roller <NUM> is spaced from the surface of the photosensitive drum <NUM>. The surface of the photosensitive drum <NUM> and the surface of the developing roller <NUM> are spaced from each other, and position of the contacting and spacing member <NUM> is a spacing position.

As shown in <FIG>, thereafter, the urging members <NUM>, <NUM> provided in the main assembly side are driven by the unshown driving source to move in the direction of arrow H. The urging members <NUM>, <NUM> contact to the force receiving portions 31e and 31f (<FIG>) provided on the photosensitive member cartridge <NUM> to apply a force thereto. By this, the portion-to-be-guided 31a (<FIG>) of the photosensitive member cartridge <NUM> contacts to a positioning portion 63c1 (<FIG>) provided in the drawer member <NUM>. The portion-to-be-guided 31b (<FIG>) contacts to the positioning portions 63d1 (<FIG>). Furthermore, the portions-to-be-guided 31c and 31d (<FIG>) fitting with the guide portions 63e and 63f (<FIG>), and, and the photosensitive member cartridge <NUM> is positioned in the drawer member <NUM>.

As has been described in the foregoing, by the function of the urging members <NUM>, <NUM>, the photosensitive member cartridge <NUM> is positioned in the main assembly.

Thereafter, in order to contact the developing roller <NUM> to the photosensitive drum <NUM>, the driving gear <NUM> further rotates, and the contacting and spacing member <NUM> is further moved to the direction of arrow G (<FIG>). By this, the force receiving portion 61a provided in the developing cartridge <NUM> separates from the second projection 42c of the contacting and spacing member <NUM> and does not receive the force from a second projection 42C. By this, the developing cartridge, <NUM> is moves downwardly with respect to the vertical direction by the weight thereof, so that the surface of the developing roller <NUM> and the surface of the photosensitive drum <NUM>, contact to each other. At this time, the portions to be positioned 61b and 62b (<FIG>) of the developing cartridge <NUM> and the positioning portions 63a and 63b (<FIG>) provided in the drawer member <NUM> are not in contact yet to each other. <FIG> is a schematic sectional view illustrating the state at that time. In this state, as has been described hereinbefore, the surface of the developing roller <NUM> and the surface of the photosensitive drum <NUM> contact to each other. The position in which the contacting and spacing member <NUM> contacts the developing roller <NUM> to the photosensitive drum <NUM> is a contacting position.

As shown in <FIG>, thereafter, an urging member <NUM> provided in the main assembly is driven by the unshown driving source to move in a direction of arrow J. The urging members <NUM> are provided on the both side surfaces of the main assembly, and four pairs thereof are provided correspondingly to the developing cartridge <NUM>.

The pair of urging members <NUM> abut to the force receiving portions 61a and 62a (<FIG>) provided on the developing cartridge <NUM> to apply a force. By this, the portions to be positioned 61b and 62b (<FIG>) of the developing cartridge <NUM> is pressed toward the positioning portions 63a and 63b (<FIG>) provided in the drawer member <NUM>. The surface of the developing roller <NUM> is pressed toward the surface of the photosensitive drum <NUM> as the fulcrum in the portions to be positioned 61b, 62b. The surface of the photosensitive drum <NUM> enters into the surface of the developing roller <NUM>, and at the time of the amount of entrances reaches the predetermined level, the portions to be positioned 61b, 62b of the developing cartridge <NUM> and the positioning portions 63a, 63b provided on the drawer member <NUM> contact to each other.

As has been described in the foregoing, the developing cartridge <NUM> is positioned in the main assembly by the urging member <NUM>.

When the positioning of the developing cartridge <NUM> is completed, the image formation is enabled in the image forming apparatus <NUM>. In this state, the contacting and spacing member <NUM> is placed in a contacting position, wherein the developing roller <NUM> can be contacted to the photosensitive drum <NUM>. As for the image forming operation, the description in Embodiment <NUM> applies.

When the image formation finishes, the urging member <NUM> is moved in the opposite direction (opposite direction to arrow J in <FIG>) to the above-described pressing direction with the unshown driving source. The driving gear <NUM> is rotated in the direction of arrow F shown in <FIG> is the opposite direction, and the contacting and spacing member <NUM> is moved in the direction of arrow I in <FIG>. By this, the contacting and spacing member <NUM> is moved to the spacing position, and the surface of the developing roller <NUM> is spaced from the surface of the photosensitive drum <NUM> (<FIG>).

Thereafter, the urging members <NUM>, <NUM> move in the opposite direction to the above-described pressing direction, and the contacting and spacing member <NUM> further moves in the direction of arrow I. By this, the surface of the photosensitive drum <NUM> is spaced from the surface of the transfer belt <NUM> (<FIG>). In this state, the device waits for the instruction of the next image formation. Or, in the case of drawing the drawer member <NUM>, the spacing is maintained between the surface of the photosensitive drum <NUM> and the surface (recording material conveying surface 11a) of the transfer belt <NUM>, and between the surface of the photosensitive drum <NUM> and the surface of the developing roller <NUM>. That is, the contacting and spacing member <NUM> is placed in the spacing position. Therefore, in drawing the drawer member <NUM> to the outside of the main assembly the damage due to the contact between the surface of the photosensitive drum <NUM> and the surface of the developing roller <NUM> by the impact at the time of the movement and so on can be suppressed. Furthermore, since this spacing can be maintained the rubbing between these surfaces can be prevented.

However, even when such a structure is employed, it is necessary to project the force receiving portion out of the drawer member in order to make the force receiving portion of the cartridge contactable to the contacting and spacing member. Therefore, the apparatus is not downsized enough. According to this embodiment, however, the contacting and spacing member <NUM> is provided in the drawer member <NUM>, and therefore, it is unnecessary to project the force receiving portion 71b too much, and the developing cartridge <NUM> can be downsized.

In the example of the transfer belt <NUM> in this embodiment, the transfer belt <NUM> feeds the sheet material S to the photosensitive drum <NUM> surface, and the developer image on the photosensitive drum <NUM> is directly transferred onto the sheet material S. However, the present invention is applicable to an image forming apparatus, wherein the developer image formed on the photosensitive drum is transferred, and finally it is re-transferred onto the recording material (sheet material) (intermediary transfer belt system).

In this embodiment, the contacting and spacing member <NUM> is provided only at the one-end portion of the drawer member <NUM>. However, the contacting and spacing member maybe similarly provided also at the other end portion of the drawer member <NUM>. However, in this case, it is preferable that the force receiving portion for receiving the force from the contacting and spacing member is also provided at the opposite ends. If the contacting and spacing members are provided on the respective sides, the shafts of the photosensitive drum and the developing roller of the photosensitive member cartridge and the developing cartridge do not incline during the movement of the cartridges. Therefore, the spacing state between the photosensitive drum and the transfer belt and the spaced state between the photosensitive drum and the developing roller can further be stabilized.

<FIG> illustrates Embodiment <NUM> of the present invention.

In Embodiment <NUM>, the photosensitive member unit (photosensitive member cartridge) and the developing unit (developing cartridge) are mounted individually to the drawer member. In this embodiment, the photosensitive member unit is fixed to the drawer member, and the developing unit (developing cartridge) is mounted to the drawer member. In Embodiments <NUM>, <NUM>, the contacting and spacing member moves in the moving direction of the drawer member. In this embodiment, the contacting and spacing member moves in a direction perpendicular to the moving direction of the drawer member. The fundamental structures except for the structures relating to the drawer member and the contacting and spacing member are the same as with the foregoing embodiments, and the description as to the common structures will be omitted when appropriate. The structural portions which are the same as with the foregoing embodiments are assigned, and the description therefor will be omitted.

Mainly referring to <FIG>, the mounting portion for the drawing unit (drawer member) will be described. <FIG> is a perspective view illustrating a mounting portion of the drawing unit in the main assembly of the apparatus of the image forming apparatus according to Embodiment <NUM> of the present invention. In <FIG>, a scanner unit or the like of the members (parts) of the main assembly of the apparatus is omitted for better illustration of the structure of the mounting portion. Parts (a) and (b) in <FIG> are perspective views as seen in different directions.

On an internal wall surface of the main assembly frame of the apparatus, there are provided opposing guiding members 14RX, 14LX for guiding a moving direction of a drawing unit U3 which will be described hereinafter. The guiding members 14RX, 14LX are rail-like members each having a channel-like section for guiding a portion-to-be-guided 13a, 13b, 13c, 13d (<FIG>) of the drawer member 63X which will be described hereinafter. The guiding members 14RX, 14LX extend substantially in the horizontal direction from a neighborhood of an entrance of the main assembly of the apparatus (neighborhood of door <NUM>) to the rear side so as to guide the drawer member 63X from a position outside of the main assembly of the apparatus to a position accommodating it in the main assembly of the apparatus.

Above the guiding members 14RX, 14LX, there is provided urging members 65X, 66X for urging and positioning the developing cartridge 60X which is a developing unit which will be described hereinafter, in a predetermined position. Urging members 65X, 66X moves downwardly by a driving force from the main assembly side of the apparatus, so that the developing cartridge 60X is urged, and are provided in order to position the developing cartridge 60X to a predetermined position in the main assembly of the apparatus.

Below the guiding member 14LX, there are provided four developing device coupling members <NUM> for transmitting the drive to the developing cartridge 60X. The four developing device coupling members <NUM> are arranged horizontally at substantially regular intervals corresponding to the developing cartridges 60X at four positions. The developing device coupling member <NUM> transmits the driving force from an unshown driving source to the developing cartridge 60X. In the state that the door <NUM> is open, the developing device coupling member <NUM> is retracted inside the side wall as shown in (b) of <FIG>, or in interrelation with closing of the door <NUM>, it enters the developing cartridge 60X side.

Referring to <FIG>, the drawing unit U3 according to Embodiment <NUM> of the present invention will be described in detail. <FIG> is a perspective view of the drawing unit for the image forming apparatus of Embodiment <NUM> of the present invention. <FIG> is a schematic sectional view of the drawing unit for the image forming apparatus of Embodiment <NUM> of the present invention. In the four drawing units U3 of this embodiment, have fundamentally the same structures and are arranged in the drawing direction. Therefore, in <FIG>, only one fundamental structure is given reference numerals for simplicity of illustration.

In this embodiment, there is provided a drawer member 63X as a supporting member which is movable between an inside position which is inside the main assembly of the apparatus and in which it supports the photosensitive drum <NUM> and demountably supports the developing cartridges 60X and an outside position outside the main assembly of the apparatus. To the drawer member 63X, the photosensitive drum <NUM>, the charging means <NUM>, the cleaning means <NUM> and the residual toner container <NUM> or the like are fixed. In addition, a contacting and spacing unit <NUM> is provided on the drawer member 63X. Thus, the drawing unit U3 of this embodiment is constituted by the drawer member 63X, the photosensitive drum <NUM>, the charging means <NUM>, the cleaning means <NUM>, the residual toner container <NUM>, and the contacting and spacing unit <NUM> and so on.

Four corners of the drawer member 63X are provided with portions-to-be-guided 13a, 13b, 13c, 13d to be guided by the guiding members 14RX, 14LX of the main assembly of the apparatus. The portions-to-be-guided 13a, 13c are guided by the guiding members 14RX, and the portions-to-be-guided 13b, 13d are guided by the guiding members 14LX. The portions-to-be-guided 13a, 13b are projected outwardly from the lateral sides, and extends in the drawing direction so that the drawing unit U3 does not tilt in the drawing position. The portions-to-be-guided 13c, 13d are of circular column configuration and project outwardly of the lateral sides.

In the side wall of one of the drawer members 63X, an opening <NUM> for passing the developing device coupling member <NUM> is provided. The developing device coupling member <NUM> is constituted such that it enters the opening <NUM> in interrelation with the closing operation. The developing device coupling member <NUM> having passed through the opening <NUM> is brought into engagement with a coupling member 45X (<FIG>) of the developing cartridge 60X. By this, the driving force is transmitted from an unshown driving source of the main assembly side of the apparatus to the developing cartridge 60X through the developing device coupling member <NUM> of the main assembly side of the apparatus and the coupling member 45X of the developing cartridge 60X.

The structure relating to positioning of the developing cartridge 60X relative to the drawer member 63X will be described.

The developing cartridge 60X is mounted to a position corresponding to the photosensitive drum <NUM> in the drawer member 63X. On each side of a region passed by the mounting developing cartridge 60X, there is provided a guide portion 13q, 13r for guiding the developing cartridge 60X into the drawer member 63X. Each guide portion 13q, 13r is provided with an elongated groove. A bottom portion of the groove of the guide portion 13q functions as a positioning portion for positioning the developing cartridge 60X. The opening <NUM> is provided adjacent to the lower end of the front side guide portion 13q in <FIG>.

Inside the guide portion 13r, the contacting and spacing unit <NUM> is provided. The contacting and spacing unit <NUM> comprises a contacting and spacing member <NUM> supporting the developing cartridge 60X, and a spring <NUM> which is an urging member for urging the contacting and spacing member <NUM> upwardly. The contacting and spacing member <NUM> is movable between a contacting position for contacting the developing roller 40X to the photosensitive drum <NUM>, and a spacing position for spacing the developing roller 40X from the photosensitive drum <NUM>.

The contacting and spacing unit <NUM> of the embodiment is provided at each side of a mounting region of the developing cartridge 60X.

Mainly referring to <FIG>, the mounting of the developing cartridge 60X (60Xy, 60Xm, 60Xc, 60Xk) to the drawer member 63X will be described. The developing cartridges 60Xy, 60Xm, 60Xc, 60Xk may be referred to as developing cartridge 60X, without the last suffixes indicating the colors when appropriate. Here, y indicates yellow developer, m indicates magenta developer, c indicates cyan developer, and k indicates black developer.

<FIG> is a perspective view illustrating behavior in the mounting of the developing cartridge to the drawer member in the image forming apparatus of Embodiment <NUM> of the present invention. In mounting the developing cartridge, the drawer member 63X has been drawn out of the main assembly of the apparatus, but in <FIG>, the main assembly of the apparatus is omitted.

The developing cartridges 60X are mounted to the mounting portions, respectively, of the drawer member 63X. The user mounts the developing cartridge 60X in the direction of an arrow C which is substantially the direction of gravity.

Each of the side surfaces of the developing cartridge 60X is provided with a projection 61X. The projection 61X is guided by the guide portion 13r provided on the drawer member 63X. An outer periphery of a coupling member 45X provided on one of the side surfaces of the developing cartridge 60X is covered by a cylindrical rib. The cylindrical rib functions as a portion-to-be-guided to be guided by the guide portion 13q provided on the drawer member 63X. The other side surface of the developing cartridge 60X is provided with a portion-to-be-guided (unshown) to be guided by the guide portion 13q provided on the drawer member 63X.

When mounting the developing cartridge 60X, the portions-to-be-guided are first engaged with guide portions 13q of the drawer member 63X. Then, the projections 61X of the developing cartridge 60X are engaged with the guide portions 13r of the drawer member 63X.

In this manner, the developing cartridge 60X is mounted in the drawer member 63X by being guided by the guide portions 13q, 13r.

Here, the developing cartridge 60X is mounted to the drawer member 63X in the state that the projections 61X is placed on the contacting and spacing member <NUM>. The contacting and spacing member <NUM> is urged upwardly by the spring <NUM> as described hereinbefore, so that the developing cartridge 60X is not mounted completely only by the weight of the developing cartridge 60X. In other words, the developing cartridge 60X is above a completely mounted position (capable of image forming operation), and the developing roller 40X is spaced from the photosensitive drum <NUM>. The pair of portions-to-be-guided of the developing cartridge 60X is not contacted to the positioning portion (bottom portion of groove) in the guide portion 13q for positioning the developing cartridge 60X.

Therefore, the developing roller 40X does not contact the photosensitive drum <NUM> only by mounting the developing cartridge 60X to the drawer member 63X. Therefore, in the mounting operation of the developing cartridge 60X, the state that the surface of the developing roller 40X and the surface of the photosensitive drum <NUM> are spaced from each other can be maintained. Thus, the damage to the surface of the photosensitive drum <NUM> due to the mounting operation of the developing cartridge 60X can be suppressed. The position in which the developing roller 40X and the photosensitive drum <NUM> can be spaced from each other is called spacing position similarly to the foregoing embodiments.

Mainly referring to <FIG>, the positioning structure for positioning the developing cartridge 60X in the main assembly of the apparatus will be described. <FIG> is a schematic sectional view illustrating a state in which the developing cartridge is mounted, and the image forming operation is not carried out in the image forming apparatus of Embodiment <NUM> according to the present invention. <FIG> is a schematic sectional view illustrating a state in which the positioning of the developing cartridge is completed (state capable of image formation) in the image forming apparatus of Embodiment <NUM> according to the present invention. In <FIG>, only the members of the members of the main assembly side of the apparatus which relate to the positioning of the developing cartridge.

When image formation instructions are produced, the developing roller 40X of the developing cartridge 60X is moved from the position (<FIG>) spaced from the photosensitive drum <NUM> to the position contacting to the photosensitive drum <NUM> (<FIG>). This enables image forming operation. The operations will be described.

The main assembly of the apparatus is provided with the pair of urging members 65X, 66X. The urging members 65X, 66X are driven by an unshown driving source to move downwardly in response to the image formation instructions (image formation signal). The urging members 65X, 66X downwardly urge the projections 61X of the both side surfaces of the developing cartridge 60X. By urging force, the pair of the projections 61X pushes down the contacting and spacing member <NUM> against the urging force of the spring <NUM>. By this, the portions-to-be-guided of the developing cartridge 60X are moved downwardly along the guide portion 13q and are stopped by the positioning portion (bottom portion of groove).

In this manner, the developing cartridge 60X is positioned. In this state, the developing roller 40X contacts to the photosensitive drum <NUM> so that the image forming operation becomes possible (<FIG>). The position in which the contacting and spacing member <NUM> is capable of contacting the surface of developing roller 40X to the surface of the photosensitive drum <NUM> is called contacting position.

In this manner, also in this embodiment, similarly to the foregoing embodiments, the contacting and spacing member <NUM> is positioned in the contacting position only when the image formation is carried out, and is positioned in the spacing position when the image forming operation is not carried out. By this, the state of the developing roller 40X not contacting to the photosensitive drum <NUM> can be established, when the image forming operation is not carried out, namely, during drawing the drawing unit U3 (drawer member <NUM> X) outwardly, and so on. Therefore, the deteriorations of various members can be suppressed, and the service lives can be extended.

Also in this embodiment, the contacting and spacing member <NUM> is provided in the drawer member 63X. Therefore, similarly to the cases of foregoing embodiments, the apparatus can be downsized.

Claim 1:
A drawer (63X) usable with an image forming apparatus (<NUM>) for forming an image on a recording material (S), the image forming apparatus (<NUM>) including a main assembly, the drawer (<NUM>, 63X) being movable between (i) an inside position in which the drawer (63X) is inside the main assembly and (ii) an outside position in which the drawer (<NUM>, 63X) is outside the main assembly, the drawer (<NUM>, 63X) comprising:
a first photosensitive drum (<NUM>);
a first mounting portion;
a first developing cartridge (60X) being detachably mounted to the first mounting portion, the first developing cartridge (60X) including a first developing roller (40X), a toner supplying roller (<NUM>), a developing blade (<NUM>), a toner container (<NUM>), and a first projection (61X) provided at each side surface of the first developing cartridge (60X), the first developing roller (40X) being configured to contact the first photosensitive drum (<NUM>);
a contacting and spacing unit (<NUM>) configured to support the first developing cartridge (60X), characterized by the
contacting and spacing unit (<NUM>) including a contacting and spacing member (<NUM>) and a first urging member (<NUM>) urging the contacting and spacing member (<NUM>),
wherein in a state where (i) the drawer (<NUM>, 63X) is in the outside position, (ii) the first developing cartridge (60X) is in a first position above a first mounted position where the first developing cartridge (60X) is capable of image forming operation and the first developing roller (40X) is spaced from the first photosensitive drum (<NUM>), and (iii) the first projection (61X) is placed on the contacting and spacing member (<NUM>), the first urging member (<NUM>) upwardly urges the contacting and spacing member (<NUM>) so that the first developing cartridge (60X) is not mounted to the first mounted position only by its weight of the first developing cartridge (60X).