Patent Publication Number: US-11385563-B2

Title: Developing cartridge having first inclined surface movable together with first shaft, and second inclined surface movable together with second shaft

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This is a by-pass continuation application of International Application No. PCT/JP2020/005457 filed on Feb. 13, 2020 which claims priority from Japanese Patent Application No. 2019-063300 filed Mar. 28, 2019. The entire contents of the earlier applications are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to a developing cartridge. 
     BACKGROUND 
     Conventionally, there have been known electro-photographic type image-forming apparatuses such as laser printers and LED printers. Such a conventional image-forming apparatus includes a developing cartridge. The developing cartridge includes a developing roller for supplying developing agent. One of such conventional image-forming apparatuses is disclosed in a prior art. The image-forming apparatus described therein includes a drum cartridge including a photosensitive drum. The developing cartridge is attachable to the drum cartridge. Upon attachment of the developing cartridge to the drum cartridge, the photosensitive drum and the developing roller contact with each other. 
     SUMMARY 
     The image-forming apparatus according to the above prior art is switchable between a state where the developing roller and the photosensitive drum are in contact with each other and a state where the developing roller and the photosensitive drum are in separation from each other. In the image-forming apparatus according to the above prior art, components for moving the developing cartridge to separate the developing roller from the photosensitive drum are provided at each side of a drum unit. The components at each side must receive a driving force from a main body of the image-forming apparatus. 
     In view of the foregoing, it is an object of the present disclosure to provide a developing cartridge capable of providing separation between the developing roller and photosensitive drum by a driving force transmitted from only one side without necessitating application of driving force to both sides. 
     In order to attain the above and other objects, according to one aspect, the present disclosure provides a developing cartridge including a casing, a developing roller, a first shaft, a first inclined surface, a second shaft, a second inclined surface, and a link mechanism. The casing is configured to accommodate developing agent therein. The developing roller is rotatable about a first axis extending in a first direction. The casing has one end portion and another end portion in the first direction. The casing also has one end portion in a second direction crossing the first direction and the developing roller is positioned at the one end portion of the casing in the second direction. The developing roller has a peripheral surface a portion of which is exposed to an outside of the casing in the second direction. The first shaft extends in the first direction and is movable relative to the casing and the developing roller in the first direction between a first position and a second position. The first shaft is also movable in the second direction together with the casing and the developing roller. The first inclined surface is inclined with respect to the first direction and is movable in the first direction together with the first shaft. The first inclined surface is inclined to be distant from the first shaft in the second direction as extending from the another end portion of the casing in the first direction toward the one end portion of the casing in the first direction. The second shaft extends in the first direction and is positioned closer to the another end portion of the casing in the first direction than the first shaft is to the another end portion of the casing in the first direction. The second shaft is movable relative to the casing and the developing roller in the first direction between a third position and a fourth position. The second shaft is also movable in the second direction together with the casing and the developing roller. The second inclined surface is inclined with respect to the first direction and is movable in the first direction together with the second shaft. The second inclined surface is inclined to be distant from the second shaft in the second direction as extending from the another end portion of the casing in the first direction toward the one end portion of the casing in the first direction. The link mechanism connects the first shaft to the second shaft. The link mechanism is configured to shift between a first state and a second state. The link mechanism is shifted to the first state to render the second shaft to be at the third position in a case where the first shaft is at the first position. The link mechanism is shifted to the second state to render the second shaft to be at the fourth position in a case where the first shaft is at the second position. 
     According to another aspect, the present disclosure also provides a developing cartridge including a casing, a developing roller, a first shaft, a first cam, a second shaft, a second cam, and a link mechanism. The casing is configured to accommodate therein developing agent. The developing roller is rotatable about a first axis extending in a first direction. The casing has one end portion and another end portion in the first direction. The first shaft extends along a second axis extending in the first direction and the first shaft is movable along the second axis. The first cam is movable together with the first shaft along the second axis. The first cam has a first inclined surface inclined with respect to the first direction. The second shaft extends along a third axis extending in the first direction and the second shaft is movable along the third axis. The second cam is movable together with the second shaft along the third axis. The second cam has a second inclined surface inclined with respect to the first direction. The link mechanism connects the first shaft to the second shaft. The second shaft and the second cam are movable along the third axis in accordance with shifting of the link mechanism from the first state to the second state. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The particular features and advantages of the embodiment(s) as well as other objects will become apparent from the following description taken in connection with the accompanying drawings, in which: 
         FIG. 1  is a schematic diagram of an image-forming apparatus; 
         FIG. 2  is a perspective view of a developing cartridge according to one embodiment; 
         FIG. 3  is a view of a drum cartridge to which the developing cartridge according to the embodiment is attached as viewed from another side thereof in a third direction; 
         FIG. 4  is a perspective view of a first guide roller supported by a bearing portion of the drum cartridge; 
         FIG. 5  is a perspective view of a second guide roller supported by a bearing portion of the drum cartridge; 
         FIG. 6  is an exploded perspective view of the developing cartridge according to the embodiment; 
         FIG. 7  is an enlarged view illustrating a link mechanism in the developing cartridge according to the embodiment in a contacting state; 
         FIG. 8  is a view of the developing cartridge and a photosensitive drum in the contacting state as viewed from one side thereof in a second direction; 
         FIG. 9  is a view of the developing cartridge and the photosensitive drum in the contacting state as viewed from one side thereof in a first direction; 
         FIG. 10  is a view of the developing cartridge and the photosensitive drum in a separated state as viewed from one side thereof in the second direction; 
         FIG. 11  is a view of the developing cartridge and the photosensitive drum in the separated state as viewed from one side thereof in the first direction; 
         FIG. 12  is an enlarged view illustrating the link mechanism in the developing cartridge according to the embodiment in the separated state; and 
         FIG. 13  is a conceptual diagram illustrating switching from the contacting state to the separated state. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, one embodiment of the disclosure will be described with reference to accompanying drawings. 
     In the following description, a direction in which a rotational axis (first axis) of a developing roller extends will be called as a “first direction.” On a peripheral surface of the developing roller, a portion exposed to outside of a casing and a portion accommodated within the casing will be assumed to be arranged side by side in a “second direction.” Here, the first direction and the second direction cross each other, preferably orthogonal to each other. Further, a direction crossing both the first and second directions (preferably, orthogonal to the first and second directions) will be called as a “third direction.” 
     1. Overall Configuration of Image-Forming Apparatus 
       FIG. 1  is a schematic diagram of an image-forming apparatus  100 . The image-forming apparatus  100  is an electrophotographic-type printer, such as a laser printer and an LED printer. As illustrated in  FIG. 1 , the image-forming apparatus  100  includes four developing cartridges  1  according to the present embodiment, a drum cartridge  2 , and a main body portion  9 . 
     1-1. Overall Configuration of Main Body Portion 
     Hereinafter, an overall configuration of the main body portion  9  will be described. As illustrated in  FIG. 1 , the main body portion  9  includes a main-body frame  101 , a transfer belt (not illustrated), and a controller  102 . 
     The main-body frame  101  is a generally rectangular parallelepiped and has an internal space therein. The drum cartridge  2  with the developing cartridges  1  attached thereto can be accommodated in the internal space of the main-body frame  101 . Further, in the main-body frame  101 , four chargers (not illustrated), four light sources (not illustrated), the transfer belt, and the controller  102  are provided. 
     The main-body frame  101  is a generally rectangular parallelepiped and defines an internal space therein. The drum cartridge  2  with the developing cartridges  1  attached thereto is configured to be accommodated in the internal space of the main-body frame  101 . In the main-body frame  101 , four chargers (not illustrated), four light sources (not illustrated), the transfer belt, and the controller  102  are also positioned. 
     The transfer belt is an endless belt for conveying printing sheets. In a state where the drum cartridge  2  to which the developing cartridges  1  are attached is positioned in the internal space of the main-body frame  101 , the transfer belt is positioned opposite to developing rollers  30  with respect to photosensitive drums  21 . The transfer belt has an outer peripheral surface contactable with outer peripheral surfaces of the respective photosensitive drums  21 . 
     The controller  102  includes a processor such as a CPU, and a main-body memory. The main-body memory is a readable and writable storage medium, such as a Flash ROM and EEPROM. The main-body memory is configured to store computer programs for controlling operations performed in the image-forming apparatus  100 . The processor is configured to execute various processing according to the computer programs stored in the main-body memory. That is, the processor is configured to execute various printing processing and other processing associated therewith to be performed in the image-forming apparatus  100 . 
     1-2. Overall Configurations of Developing Cartridges 
     An overall structure of each developing cartridge  1  will be described next with reference to  FIGS. 1 and 2 .  FIG. 2  is a perspective view of the developing cartridge  1  according to the embodiment. 
     As illustrated in  FIG. 1 , the developing cartridges  1  are attachable to and detachable from a frame  200  of the drum cartridge  2 . As illustrated in  FIG. 2 , each developing cartridge  1  includes a casing  10  configured to store therein developing agent. The casing  10  includes a container portion  10 A, and a lid portion  10 B. The container portion  10 A defines an internal space therein. The lid portion  10 B is flat plate shaped. The lid portion  10 B is positioned at one end portion of the casing  10  in the second direction. The lid portion  10 B has a third outer surface  13  (outer surface) described later. The lid portion  10 B covers an opening portion positioned at one end portion of the container portion  10 A in the second direction. The container portion  10 A has one end portion in the third direction where an opening  10 C is formed. A developing roller  30  (described later) is positioned at the opening  10 C. 
     The casing  10  has one end portion in the first direction which has a first outer surface  11 . The casing  10  has another end portion in the first direction which has a second outer surface  12 . The casing  10  also has the third outer surface  13  and a fourth outer surface  14  ( FIG. 9 ) spaced away from each other in the second direction. The third outer surface  13  is positioned at one end portion of the casing  10  in the second direction. The fourth outer surface  14  is positioned at another end portion of the casing  10  in the second direction. The third outer surface  13  extends in a direction crossing the second direction. 
     The four developing cartridges  1  accommodate therein toner of different colors (for example, cyan, magenta, yellow and black), respectively. However, the four developing cartridges  1  may accommodate therein toner of an identical color. 
     Each developing cartridge  1  includes one developing roller  30 . The developing roller  30  is cylindrical in shape. The developing roller  30  is rotatable about a rotational axis (first axis) extending in the first direction. The developing roller  30  is supported by the casing  10  so as to be rotatable about the first axis. 
     The developing roller  30  includes a developing-roller body  31  and a developing-roller shaft  32 . The developing-roller body  31  is hollow cylindrical in shape and extends in the first direction. The developing-roller body  31  is made from an elastic material, such as rubber. The developing-roller shaft  32  is a solid cylindrical member penetrating through the developing-roller body  31  in the first direction. The developing-roller shaft  32  is made from meal or electrically conductive resin. The developing-roller body  31  is fixed to the developing-roller shaft  32  without relative rotation therebetween. That is, the developing-roller body  31  is rotatable together with the developing-roller shaft  32  about the developing-roller axis. A part of an outer peripheral surface of the developing-roller body  31  in the second direction is exposed to the outside of the casing  10  through the opening  10 C. A remaining part in the second direction of the outer peripheral surface of the developing-roller body  31  is positioned inside the casing  10 . 
     The developing-roller shaft  32  has one end portion in the first direction. A developing-roller gear (not illustrated) is attached to the one end portion of the developing-roller shaft  32  in the first direction. The developing-roller gear is positioned at the first outer surface  11 . The developing-roller gear is fixed to the one end portion of the developing-roller shaft  32  without relative rotation therebetween. Hence, a rotation of the developing-roller gear causes a rotation of the developing-roller shaft  32 , so that the developing-roller body  31  is rotatable together with the developing-roller shaft  32 . 
     Incidentally, the developing-roller shaft  32  may not extend through the developing-roller body  31  in the first direction. For example, the developing-roller shaft  32  may be configured of two shafts extending outward in the first direction respectively from both ends of the developing-roller body  31  in the first direction. 
     As illustrated in  FIG. 2 , each developing cartridge  1  also includes a gear portion  40 . The gear portion  40  is positioned at the first outer surface  11  of the casing  10 . The gear portion  40  includes the developing-roller gear described above, a coupling  41 , and a gear cover  43 . 
     The coupling  41  is a rotary member configured to receive a driving force supplied from a power source in the image-forming apparatus  100 . The coupling  41  is rotatable about a rotational axis extending in the first direction. The coupling  41  has a fixing hole  411  recessed inward in the first direction. Upon attachment of the drum cartridge  2  to the main body portion  9  with the developing cartridges  1  attached to the drum cartridge  2 , a transmission shaft (not shown) of the main body portion  9  is configured to be inserted in the fixing hole  411 . The transmission shaft and the coupling  41  are thus connected each other without relative rotation therebetween. Accordingly, rotation of the transmission shaft causes rotation of the coupling  41 . In accordance with the rotation of the coupling  41 , the developing-roller gear rotates together with the developing roller  30 . The rotation of the coupling  41  also causes rotations of a supply roller (not illustrated) and an agitator (not illustrated). 
     A handle  38  for being gripped by a user is positioned at an outer surface of another end portion of the casing  10  at the other side in the third direction. 
     1-3. Overall Configuration of Drum Cartridge 
     Next, an overall configuration of the drum cartridge  2  will be described next with reference to  FIGS. 1 and 3 .  FIG. 3  is a plan view of the drum cartridge  2  according to the embodiment. As illustrated in  FIGS. 1 and 3 , the drum cartridge  2  includes four of the photosensitive drums  21 , and the frame  200 . 
     Each of the four photosensitive drums  21  has a cylindrical-shaped outer peripheral surface centered on a drum axis, which is a rotational axis extending in the first direction. The outer peripheral surface is a surface coated with photosensitive material. Each of the four photosensitive drums  21  is rotatable about the drum axis. 
     The frame  200  illustrated in  FIG. 3  is a frame supporting the four photosensitive drums  21 . The frame  200  holds the four photosensitive drums  21  such that the photosensitive drums  21  are spaced away from one another in the second direction. The frame  200  includes a pair of side frames (drum frames)  201 ,  202  opposite each other in the first direction. The side frame  202  is positioned further in the first direction toward the other side than the side frame  201 . The photosensitive drums  21  are rotatably supported by the side frames  201  and  202 . 
     For performing a printing process in the image-forming apparatus  100 , the controller  102  drives a motor (not illustrated) so that the photosensitive drums  21  and the developing rollers  30  can rotate by a driving force transmitted from the motor through the transmission shaft and the coupling  41 . Further, the controller  102  supplies power to the chargers (not illustrated) to charge the outer peripheral surfaces of the respective photosensitive drums  21 . The controller  102  further causes the light sources (not illustrated) to emit light onto the outer peripheral surfaces of the respective photosensitive drums  21 . In this way, an electrostatic latent image corresponding to a printing image is formed on the outer peripheral surface of each photosensitive drum  21 . The toner accommodated in each developing cartridge  1  is then supplied through the corresponding developing roller  30  to the electrostatic latent image formed on the corresponding photosensitive drum  21 . Thus, the electrostatic latent image becomes a visible toner image on the outer peripheral surface of each photosensitive drum  21 . 
     Then, a printing sheet is conveyed between each photosensitive drum  21  and the transfer belt, whereby the toner image is transferred from the outer peripheral surface of each photosensitive drum  21  onto the printing sheet. The printing sheet carrying the toner image is then conveyed to a fixing unit (not illustrated) where the toner image is thermally fixed to the printing sheet. Image printing on the printing sheet is performed in this way. 
     In the image-forming apparatus  100 , it may be preferable that the developing rollers  30  be separated from the corresponding photosensitive drums  21 , for example, in order to change colors for printing or during a standby period. For this purpose, the image-forming apparatus  100  of the present embodiment provides a contacting state and a separated state. The contacting state denotes a state where the developing rollers  30  and the photosensitive drums  21  are in contact with each other in a state where the developing cartridges  1  are attached to the drum cartridge  2 . The separated state denotes a state where the developing rollers  30  and the photosensitive drums  21  are separated from each other in the state where the developing cartridges  1  are attached to the drum cartridge  2 . 
     To this effect, as components for realizing the contact and the separation, each developing cartridge  1  includes a first shaft  61 , a second shaft  62 , a first cam  63 , a second cam  64 , a link mechanism  65 , a first ring  66 , a second ring  67 , and a resilient member  69  (see  FIG. 6 ). Further, as components for realizing the contact and the separation, the drum cartridge  2  includes a first guide roller (pressure contact portion)  24 , and a second guide roller (pressure contact portion)  25 . As components for realizing the contact and the separation, the main body portion  9  includes four drive shafts  103 . 
     2. Components in Drum Cartridge for Contact and Separation 
     Hereinafter, components of the drum cartridge  2  for performing the contact and the separation between the developing rollers  30  and the photosensitive drums  21  will be described with reference to  FIGS. 3 through 5 . 
     As illustrated in  FIG. 3 , in the state where the developing cartridges  1  are attached to the drum cartridge  2 , the first outer surface  11  of each developing cartridge  1  faces an inner surface of the first side frame  201  in the first direction. Also, in the state where the developing cartridges  1  are attached to the drum cartridge  2 , the second outer surface  12  of each developing cartridge  1  faces an inner surface of the second side frame  202  in the first direction. 
     As indicated by a broken line in a partially enlarged view in  FIG. 3 , the first side frame  201  includes the first guide roller  24 . That is, the first guide roller  24  is positioned at one end portion of the frame  200  in the first direction. 
       FIG. 4  is an exploded perspective view of the first guide roller  24  and a bearing portion  26  holding the first guide roller  24 . As illustrated in  FIG. 4 , the first guide roller  24  has an outer peripheral surface (pressure contact surface)  240  of a cylindrical shape extending in the third direction. The first guide roller  24  has end portions in the third direction each rotatably supported by the bearing portion  26 . Thus, the first guide roller  24  is rotatable about a center axis thereof extending in the third direction. 
     As indicated by a broken line in another partially enlarged view in  FIG. 3 , the second side frame  202  includes the second guide roller  25 . That is, the second guide roller  25  is positioned at another end portion of the frame  200  in the first direction. 
       FIG. 5  is an exploded perspective view of the second sleeve  25  and a bearing portion  27  holding the second guide roller  25 . The second guide roller  25  has a cylindrical-shaped outer peripheral surface (pressure contact surface)  250  extending in the third direction. The second guide roller  25  has end portions in the third direction each rotatably supported by the bearing portion  27 . Thus, the second guide roller  25  is rotatable about a center axis thereof extending in the third direction. 
     The first guide roller  24  and the second guide roller  25  are positioned to be aligned with each other in the first direction as a pair. As will be described later, a first inclined surface  63   a  of the first cam  63  is contactable with the outer peripheral surface  240  of the first guide roller  240 , and a second inclined surface  64   a  of the second cam  64  is contactable with the outer peripheral surface  250  of the second guide roller  25 . 
     3. Components in Main Body Portion for Contact and Separation 
     Next, a component of the main body portion  9  for realizing the contact and separation between the developing rollers  30  and the photosensitive drums  21  will be described. 
     The main body portion  9  includes the drive shafts  103  (see  FIGS. 8 and 10 ) as components for performing the contact and the separation. Each drive shaft  103  is a solid cylinder or solid prismatic column extending in the first direction. The drive shaft  103  is movable in the first direction between an advanced position and a retracted position upon receiving a driving force from a power source of the main body portion  9 . 
     4. Components in Developing Cartridge for Contact and Separation 
     Next, components of the developing cartridge  1  for realizing the contact and the separation between the developing rollers  30  and the photosensitive drums  21  will be described with reference to  FIGS. 2, 6 and 7 .  FIG. 6  is an exploded perspective view of the developing cartridge  1  according to the embodiment.  FIG. 7  is an enlarged view of the link mechanism  65  in the contacting state. 
     The first shaft  61  has a solid cylindrical shape or solid prismatic columnar shape extending in the first direction. The first shaft  61  is held at the third outer surface  13  of the casing  10  so as to be movable in the first direction, relative to the casing  10  and the developing roller  30 , between a first position and a second position (described later). The first shaft  61  is held at the third outer surface  13  so as to be movable in the second direction together with the casing  10  and the developing roller  30 . 
     Specifically, the lid portion  10 B has a first guide groove  10 D at the third outer surface  13 . The first guide groove  10 D extends along a second axis extending in the first direction. The first guide groove  10 D has one end portion at the one side in the first direction. The first ring  66  is positioned at the one end portion of the first guide groove  10 D in the first direction. The first ring  66  is hollow cylindrical and extends in the first direction. The first ring  66  of the embodiment is held by the gear cover  43 . Alternatively, the first ring  66  may be integral with the gear cover  43 . The first ring  66  is positioned between the first cam  63  and the link mechanism  65  in the first direction. The first shaft  61  is inserted in the first ring  66  and is slidably held by the first guide groove  10 D. The first shaft  61  is thus positioned along the second axis. The first shaft  61  is movable in the first direction along the second axis. 
     The second shaft  62  has a solid cylindrical shape or solid prismatic columnar shape extending in the first direction. The first shaft  61  is held at the third outer surface  13  of the casing  10  so as to be movable in the first direction, relative to the casing  10  and the developing roller  30 , between a third position and a fourth position described later. The second shaft  62  is held at the third outer surface  13  so as to be movable in the second direction together with the casing  10  and the developing roller  30 . 
     Specifically, the lid portion  10 B also has a second guide groove  10 E at the third outer surface  13 . The second guide groove  10 E extends along a third axis extending in the first direction. The second guide groove  10 E is positioned further in the first direction toward the other side than the first guide groove  10 D. The second guide groove  10 E has another end portion at the other side in the first direction. The second ring  67  is positioned at the other end portion of the second guide groove  10 E in the first direction. The second ring  67  is hollow cylindrical and extends in the first direction. The second ring  67  is held by the other end portion of the second guide groove  10 E in the first direction. The second ring  67  is positioned between the second cam  64  and the link mechanism  65  in the first direction. The second shaft  62  is inserted in the second ring  67  and is slidably held by the second guide groove  10 E. Hence, the second shaft  62  is positioned along the third axis at a position closer to the other end portion in the first direction of the casing  10  than the first shaft  61  is to the other end portion in the first direction of the casing  10 . The second shaft  62  is movable in the first direction along the third axis. 
     The first cam  63  is connected to one end portion of the first shaft  61  in the first direction. The first cam  63  is positioned further in the first direction toward the one side (outward) than the first ring  66 . The first cam  63  is movable in the first direction together with the first shaft  61  along the second axis. The first cam  63  of the present embodiment is conical in shape. The first cam  63  has an outer peripheral surface including the first inclined surface  63   a . The first inclined surface  63   a  is inclined with respect to the first direction with an acute angle. The first inclined surface  63   a  is movable together with the first shaft  61  in the first direction. The first inclined surface  63   a  is sloped to be distant from the first shaft  61  in the second direction as extending in the first direction from the other side toward the one side. 
     The second cam  64  is connected to another end portion of the second shaft  62  at the other side in the first direction. The second cam  64  is positioned further in the first direction toward the other side (outward) than the second ring  67 . The second cam  64  is movable together with the second shaft  62  in the first direction along the third axis. The second cam  64  of the present embodiment is semi-conical in shape. The second cam  64  has an outer peripheral surface including the second inclined surface  64   a . The second inclined surface  64   a  is sloped with respect to the first direction with an acute angle. The second inclined surface  64   a  is movable together with the second shaft  62  in the first direction. The second inclined surface  64   a  is inclined to be distant from the second shaft  62  in the second direction as extending in the first direction from the other side toward the one side. 
     The link mechanism  65  connects the first shaft  61  to the second shaft  62 . The link mechanism  65  includes a first link  651 , a second link  652 , a connection bar  653 , a first screw  655 , and a second screw  656 . The link mechanism  65  is switchable between a first state and a second state. 
       FIGS. 2 and 6 to 8  illustrate the first state of the link mechanism  65 . In the first state, the first link  651  extends in the third direction. The first link  651  has a plate-like shape crossing the second direction. The first link  651  includes a plate portion  651   d , a protruding portion  651   b , and a narrow portion  651   c . The protruding portion  651   b  is another end portion of the first link  651  at the other side in the third direction. The protruding portion  651   b  is circular in shape as viewed in the second direction. The narrow portion  651   c  is positioned further in the third direction toward the one side than the protruding portion  651   b . That is, the narrow portion  651   c  is positioned between the protruding portion  651   b  and the plate portion  651   d  in the third direction in the first state. The narrow portion  651   c  has a width in the first direction smaller than respective widths of the protruding portion  651   b  and the plate portion  651   d.    
     As illustrated in  FIG. 7 , the first shaft  61  has another end portion in the first direction at the other side. The other end portion of the first shaft  61  has a first guide recess  61   a . The first guide recess  61   a  is recessed in the second direction toward the other side from the one side. The first guide recess  61   a  extends in the third direction to penetrate, in the third direction, the other end portion of the first shaft  61  in the first direction. The first guide recess  61   a  has a first inner wall surface at the other side in the first direction. The first inner wall surface is a flat plane extending perpendicular to the first direction. The first guide recess  61   a  also has a second inner wall surface at the one side in the first direction. The second inner wall surface has a first guide sloped surface  61   b  sloping to be distant from the first inner wall surface in the first direction as extending in the third direction toward the one side from the other side. 
     The first guide recess  61   a  has an open end portion at the other side in the third direction. The protruding portion  651   b  of the first link  651  is engaged with the open end portion of the first guide recess  61   a . Hence, the other end portion of the first link  651  in the third direction is connected to the other end portion of the first shaft  61  in the first direction. The first link  651  includes a third boss  651   e  positioned at one end portion of the plate portion  651   d  in the third direction (see  FIG. 7 ). The third boss  651   e  is solid cylindrical in shape and protrudes in the second direction toward the other side. The first link  651  has a third through-hole  651   a  ( FIG. 6 ) positioned between both end portions of the first link  651  in the third direction in the first state of the link mechanism  65 . 
     As illustrated in  FIGS. 2 and 6 to 8 , in the first state, the second link  652  extends in the third direction. The second link  652  has a plate-like shape crossing the second direction. The first link  651  includes a protruding portion  652   b , a plate portion  652   d , and a narrow portion  652   c . The protruding portion  652   b  is another end portion of the second link  652  at the other side in the third direction. The protruding portion  652   b  is circular in shape as viewed in the second direction. The narrow portion  652   c  is positioned further in the third direction toward the one side than the protruding portion  652   b . That is, the narrow portion  652   c  is positioned between the protruding portion  652   b  and the plate portion  652   d  in the third direction in the first state. The narrow portion  652   c  has a width in the first direction smaller than respective widths of the protruding portion  652   b  and the plate portion  652   d.    
     As illustrated in  FIG. 7 , the second shaft  62  has one end portion at the one side in the first direction. The one end portion of the shaft  62  in the first direction has a second guide recess  62   a . The second guide recess  62   a  is recessed in the second direction toward the other side. The second guide recess  62   a  extends in the third direction to penetrate, in the third direction, the one end portion of the second shaft  62  in the first direction. The second guide recess  62   a  has a first inner wall surface at the other side in the first direction. The first inner wall surface is a flat plane extending perpendicular to the first direction. The second guide recess  62   a  also has a second inner wall surface at the other side in the first direction. The second inner wall surface has a second guide sloped surface  62   b  sloping to be distant from the first inner wall surface in the first direction as extending in the third direction toward the one side from the other side. 
     The second guide recess  62   a  has an open end portion at the other side in the third direction. The protruding portion  652   b  of the second link  652  is engaged with the open end portion of the second guide recess  62   a . Hence, the other end portion of the second link  652  in the third direction is connected to the one end portion of the second shaft  62  in the first direction. The second link  652  includes a fourth boss  652   e  positioned at one end portion of the plate portion  652   d  in the third direction (see  FIG. 7 ). The fourth boss  652   e  is solid cylindrical in shape and protrudes in the second direction toward the other side. The second link  652  has a fourth through-hole  652   a  ( FIG. 6 ) positioned between the one end portions and the other end portions of the second link  652  in the third direction in the first state of the link mechanism  65 . 
     As illustrated in  FIGS. 2 and 6 , the connection bar  653  extends in the first direction. The connection bar  653  is flat-plate shaped, and extends in a direction crossing the second direction. The connection bar  653  has one end portion in the first direction having a first through-hole  653   a . The first through-hole  653   a  extends through a thickness of the connection bar  653  in the second direction. The connection bar  653  has another end portion in the first direction having a second through-hole  653   b . The second through-hole  653   b  extends through the thickness of the connection bar  653  in the second direction. 
     The third boss  651   e  of the first link  651  is inserted in the first through-hole  653   a  of the connection bar  653 . The fourth boss  652   e  of the second link  652  is inserted in the second through-hole  653   b  of the connection bar  653 . In this way, the connection bar  653  is connected to the one end portion in the third direction of the first link  651  and to the one end portion in the third direction of the second link  652 . 
     The lid portion  10 B has an intermediate portion in the first direction. The intermediate portion has a recessed portion  10 F recessed in the second direction toward the other side. Inside the recessed portion  10 F, the other end portion in the first direction of the first shaft  61 , the one end portion in the first direction of the second shaft  62 , the first link  651 , the second link  652 , and the connection bar  653  are positioned. 
     The recessed portion  10 F has a bottom surface from which a first boss  657  protrudes in the second direction toward the one side. The first boss  657  is hollow cylindrical in shape. The first boss  657  has an inner peripheral surface formed with a female thread. Further, a second boss  658  protrudes from the bottom surface of the recessed portion  10 F in the second direction toward the one side. The second boss  658  is hollow cylindrical in shape. The second boss  658  has an inner peripheral surface formed with a female thread. The second boss  658  is positioned away from the first boss  657  in the first direction. The second boss  658  is positioned further in the first direction toward the other side than the first boss  657 . 
     The first screw  655  extends in the second direction. The first screw  655  has a head portion at the one side, and a shaft portion at the other side in the second direction. The shaft portion has an outer peripheral surface formed with a male thread. The first screw  655  pivotally movably supports the first link  651  relative to the casing  10 . 
     Specifically, the third boss  651   e  of the first link  651  is inserted in the first through-hole  653   a  of the connection bar  653 , and the protruding portion  651   b  of the first link  651  is engaged with the open end portion of the first guide recess  61   a . In this state, the shaft portion of the first screw  655  is threadingly engaged with the first boss  657 . Hence, the first link  651  is pivotally movable about the first screw  655 . That is, the first link  651  is pivotally movable about a first pivot axis extending in the second direction. 
     The second screw  656  extends in the second direction. The second screw  656  has a head portion at the one side, and a shaft portion at the other side in the second direction. The shaft portion has an outer peripheral surface formed with a male thread. The second screw  656  pivotally movably supports the second link  652  relative to the casing  10 . 
     Specifically, the fourth boss  652   e  of the second link  652  is inserted in the second through-hole  653   b  of the connection bar  653 , and the protruding portion  652   b  of the second link  652  is engaged with the open end portion of the second guide recess  62   a . In this state, the shaft portion of the second screw  656  is threadingly engaged with the second boss  658 . Hence, the second link  652  is pivotally movable about the second screw  656 . That is, the second link  652  is pivotally movable about a second pivot axis extending in the second direction. 
     As illustrated in  FIG. 6 , the resilient member  69  is a coil spring which is a metal wire helically wound. The resilient member  69  is expandable and shrinkable in the first direction. The resilient member  69  is held inside the first ring  66  such that: one end in the first direction of the resilient member  69  is connected to an inner peripheral surface of the first ring  66 ; and another end of the resilient member  69  in the first direction is connected to an outer peripheral surface of the first shaft  61 . The resilient member  69  is compressed in the first direction to have a length smaller than a natural length of the resilient member  69 . With this structure, the resilient member  69  urges the first shaft  61  in the first direction toward the one side. In other words, the resilient member  69  urges the first shaft  61  in a direction from the second position toward the first position. 
     5. Movement of Each Component at the Time of Switching Between Contact and Separation 
     Hereinafter, how each component operates for realizing switching between the contact and the separation will be described with reference to  FIGS. 7 through 13 . 
       FIG. 8  is a view of the developing cartridge  1  and the photosensitive drum  21  in the contacting state as viewed from the one side thereof in the second direction.  FIG. 9  is a view of the developing cartridge  1  and the photosensitive drum  21  in the contacting state as viewed from one side thereof in the first direction.  FIG. 10  is a view of the developing cartridge  1  and the photosensitive drum  21  in the separated state as viewed from one side thereof in the second direction.  FIG. 11  is a view of the developing cartridge  1  and the photosensitive drum  21  in the separated state as viewed from one side thereof in the first direction.  FIG. 12  is an enlarged view illustrating the link mechanism  65  in the separated state.  FIG. 13  is a conceptual diagram illustrating switching from the contacting state to the separated state. 
     In the image-forming apparatus  100 , in a case where the drive shaft  103  is driven or moved toward the advanced position toward the other side in the first direction, one end surface of the corresponding first cam  63  facing toward the one side in the first direction is pressed by the drive shaft  103 . That is, the first cam  63  receives a pressing force F directing from the one end portion toward the other end portion in the first direction of the casing  10 . 
     The pressing force F applied to the first cam  63  is greater than an urging force of the resilient member  69  applied to the first shaft  61  and the first cam  63 . Hence, the first shaft  61  is moved together with the first cam  63  from the first position ( FIG. 8 ) to the second position ( FIG. 10 ). Accordingly, the first guide recess  61   a  is also moved in the direction from the one end portion toward the other end portion in the first direction of the casing  10 . The first link  651  is thus caused to pivotally move counterclockwise about the first pivot axis as viewed from the one side thereof in the second direction. 
     At this time, the narrow portion  651   c  of the first link  651  is tilted along the first guide sloped surface  61   b , as illustrated in  FIG. 12 . Accordingly, the connection bar  653  is pulled by the one end portion in the third direction of the first link  651 , so that the connection bar  653  is moved in a direction from the other end portion to the one end portion in the first direction of the casing  10 . 
     In accordance with the movement of the connection bar  653 , the one end portion in the third direction of the second link  652  is pulled by the connection bar  653 , thereby causing the second link  652  to pivot about the second pivot axis. Specifically, the second link  652  pivotally moves counterclockwise about the second pivot axis as viewed from the one side thereof in the second direction. Pivotal movement of the second link  652  is performed generally in parallel with pivotal movement of the first link  651 . At this time, the narrow portion  652   c  of the second link  652  is tilted along the second guide sloped surface  62   b . As a result, the protruding portion  652   b  pushes the second guide recess  62   a , so that the second shaft  62  is moved in the direction from the one end portion to the other end portion in the first direction of the casing  10 . Thus, the second shaft  62  is moved together with the second cam  64  from the third position ( FIG. 8 ) to the fourth position ( FIG. 10 ). 
     In this way, upon application of the pressing force F in the first direction from the drive shaft  103  to the first cam  63 , the first shaft  61  is moved from the first position to the second position, so that the link mechanism  65  is switched from the first state (illustrated in  FIGS. 7 and 8 ) to the second state (illustrated in  FIGS. 10 and 12 ). Consequently, the second shaft  62  is moved from the third position to the fourth position. 
     In the meantime, the first inclined surface  63   a  of the first cam  63  is in contact with the outer peripheral surface  240  of the first guide roller  24  of the first side frame  201 . Here, a contacting position of the first inclined surface  63   a  with the first guide roller  24  is gradually shifted from a position near the other end toward a position near the one end in the first direction of the first inclined surface  63   a  (see  FIG. 13 ). As a result, a distance between the drum cartridge  2  (the outer peripheral surface  240 ) and the casing  10  in the second direction is gradually increased. Hence, as illustrated in  FIG. 13 , since the first sloped surface  63   a  is pressed by the outer peripheral surface  240  of the first guide roller  24  of the drum cartridge  2 , the casing  10  and the developing roller  30  are caused to move together with the first cam  63  in the second direction to separate the developing roller  30  from the corresponding photosensitive drum  21 . 
     In response to the movement of the first cam  63  from the first position to the second position, the second cam  64  also moves from the third position to the fourth position. Accordingly, as illustrated in  FIG. 13 , since the second sloped surface  64   a  is also pressed by the outer peripheral surface  250  of the second guide roller  25  of the drum cartridge  2 , the casing  10  and the developing roller  30  are caused to move together with the second cam  64  in the second direction. 
     In this way, both end portions of the casing  10  in the first direction are respectively pressed by the first guide roller  24  and the second guide roller  25  which are parts of the drum cartridge  2 , so that the casing  10  is moved from the one side toward the other side in the second direction relative to the drum cartridge  2 . With this structure, inclination of the casing  10  with respect to the first direction can be restrained at the time of switching between the contacting state ( FIGS. 8 and 9 ) and the separated state ( FIGS. 10 and 11 ). 
     In a case where the drive shaft  103  is moved to its retracted position, that is, moved in the direction from the other end portion to the one end portion in the first direction of the casing  10 , the first shaft  61  is moved relative to the casing  10  in the first direction from the other end portion toward the one end portion of the casing  10  by the urging force of the resilient member  69 . Hence, the first shaft  61  is moved together with the first cam  63  from the second position ( FIG. 10 ) to the first position ( FIG. 8 ). In accordance with this movement of the first shaft  61 , the first guide recess  61   a  is also moved in the first direction from the other end portion to the one end portion of the casing  10 . 
     As a result, the first link  651  is pivotally moved about the first pivot axis in a clockwise direction as viewed in the second direction from the one side toward the other side. At this time, the narrow portion  651   c  of the first link  651  extends along the first inner wall surface of the first guide recess  61   a  (see  FIG. 7 ). In other words, since the movement of the narrow portion  651   c  of the first link  651  is restrained by the first inner wall surface of the first guide recess  61   a , further pivotal movement of the first link  651  in the clockwise direction is restrained. Accordingly, the first link  651  is maintained in a posture extending in the third direction, as illustrated in  FIG. 7 . 
     In accordance with the pivotal movement of the first link  651  in the clockwise direction, the connection bar  653  is pushed by the one end portion in the third direction of the first link  651 , so that the connection bar  653  is cause to move in the first direction from the one end portion toward the other end portion of the casing  10 . 
     Further, the one end portion in the third direction of the second link  652  is pushed by the connection bar  653 , which causes pivotal movement of the second link  652 . Specifically, the second link  652  is caused to pivotally move about the second pivot axis in the clockwise direction as viewed from the one side thereof in the second direction. The pivotal movement of the second link  652  is performed generally in parallel with the pivotal movement of the first link  651 . 
     At this time, the narrow portion  652   c  of the second link  652  extends along the first inner wall surface of the second guide recess  62   a  (see  FIG. 7 ). In other words, since the movement of the narrow portion  652   c  of the second link  652  is restrained by the first inner wall surface of the second guide recess  62   a , further pivotal movement of the second link  652  in the clockwise direction is restrained. Accordingly, as illustrated in  FIG. 7 , the second link  652  is maintained in the posture extending in the third direction. 
     The protruding portion  652   b  of the second link  652  pulls the second shaft  62  by the pivotal movement of the second link  652 , so that the second shaft  62  is moved in the first direction from the other end portion toward the one end portion of the casing  10 . Hence, the second shaft  62  is moved from the fourth position ( FIG. 10 ) to the third position ( FIG. 8 ) together with the second cam  64 . 
     In a state where the pressing force F from the drive shaft  103  is no longer applied to the corresponding first cam  63 , the first shaft  61  is moved from the second position to the first position, the link mechanism  65  is shifted from the second state to the first state, and accordingly, the second shaft  62  is caused to move from the fourth position to the third position. 
     Here, the frame  200  of the drum cartridge  2  includes a pressure mechanism (not illustrated) for pressing the casing  10  of each developing cartridge  1  toward the corresponding photosensitive drum  21 . By this pressure mechanism, the developing cartridge  1  is then pressed in the second direction toward the one side, so that the contacting state between the developing roller  30  and the photosensitive drum  21  is restored. As such, the state of the image-forming apparatus  100  is switchable between the contacting state ( FIGS. 7 and 8 ) and the separated state ( FIGS. 8 and 10 ). 
     Strictly speaking, the first inclined surface  63   a  is not in contact with the side frame  201  and the second inclined surface  64   a  is not in contact with the side frame  202  in a case where the first shaft  61  is at the first position and the second shaft  62  is at the third position. That is, the first inclined surface  63   a  and the second sloped surface  64   a  are brought into contact with the side frames  201  and  202 , respectively, when the first shaft  61  starts moving from the first position toward the second position and the second shaft  62  starts moving from the third position toward the fourth position. Further, the first inclined surface  63   a  and the second inclined surface  64   a  are kept in contact with the side frames  201  and  202 , respectively, when the first shaft  61  is positioned at the second position and the second shaft  62  is positioned at the fourth position. In this state, the developing roller  30  is in separation from the corresponding photosensitive drum  21 . 
     6. Summary 
     The developing cartridge  1  according to the embodiment includes the casing  10 , the developing roller  30 , the first shaft  61 , the first inclined surface  63   a , the second shaft  62 , the second inclined surface  64   a , and the link mechanism  65 . The link mechanism  65  is in the first state ( FIG. 7 ) and the second shaft  62  is at the third position ( FIG. 8 ), when the first shaft  61  is at the first position. The link mechanism  65  is in the second state ( FIG. 12 ) and the second shaft  62  is at the fourth position when the first shaft  61  is at the second position ( FIG. 10 ). 
     With this structure, the first inclined surface  63   a  and the second inclined surface  64   a  are pressed by the first guide roller  24  of the first side frame  201  and the second guide roller  25  of the second side frame  202 , respectively, during the movement of the first shaft  61  from the first position toward the second position and the movement of the second shaft  62  from the third position toward the fourth position. Hence, the developing roller  30  is moved in the second direction toward the other side. 
     As such, in the developing cartridge  1  according to the embodiment, separation of the developing roller  30  from the photosensitive drum  21  can be performed by the driving force applied only to the one side in the first direction of the developing cartridge  1 . Application of driving force to both sides in the first direction of the developing cartridge  1  is unnecessary. 
     Further, the link mechanism  65  of the developing cartridge  1  according to the embodiment includes the first link  651 , the second link  652 , and the connection bar  653 . With this structure, enhanced mechanical strength of each component can be obtained in comparison with a conceivable structure where the first inclined surface  63   a  and the second inclined surface  64   a  are connected together directly by a single shaft. 
     Further, in the developing cartridge  1  according to the embodiment, the third outer surface  13  of the casing  10  has the recessed portion  10 F in which the first link  651 , the second link  652 , and the connection bar  653  are positioned. This structure can reduce a likelihood that light emitted from a light source provided in the main body portion  9  toward the photosensitive drum  21  is blocked by the link mechanism  65 . 
     Further, the developing cartridge  1  according to the embodiment includes the resilient member  69 . The first shaft  61  can be returned to the first position and the second shaft  62  can be returned to the third position by the urging force of the resilient member  69  after the first shaft  61  has moved from the first position to the second position and the second shaft  62  has moved from the third position to the fourth position. 
     Further, the developing cartridge  1  according to the embodiment includes the casing  10 , the developing roller  30 , the first shaft  61 , the first cam  63 , the second shaft  62 , the second cam  64 , and the link mechanism  65 . The link mechanism  65  is shifted from the first state to the second state in accordance with the movement of the first shaft  61  along the second axis. The second shaft  62  and the second cam  64  are moved along the third axis in accordance with shifting of the link mechanism  65  from the first state to the second state. Hence, the first inclined surface  63   a  of the first cam  63  and the second inclined surface  64   a  of the second cam  64  are pressed by the first guide roller  24  of the first side frame  201  and the second guide roller  25  of the second side frame  202 , respectively, during the movement of the first shaft  61  along the second axis and the movement of the second shaft  62  along the third axis. As a result, the developing roller  30  can be moved in the direction crossing the first direction. 
     7. Modifications 
     While the disclosure has been described in detail with reference to the above embodiment, it would be apparent to those skilled in the art that many modifications and variations may be made therein without departing from the scope of the disclosure. 
     For example, in the above-described embodiment, the resilient member  69  for urging the first shaft  61  from the second position to the first position is provided. Instead or in addition to the resilient member  69 , a resilient member for urging the second shaft  62  from the fourth position to the third position may be provided. 
     In the above-described embodiment, the resilient member  69  for urging the first shaft  61  from the second position to the first position is provided. Instead or in addition to the resilient member  69 , a resilient member for urging the link mechanism  65  from the second state to the first state may be provided. Specifically, a torsion spring may be used as the resilient member. The torsion spring has one end portion connected to the first link  651 , and another end portion connected to the casing  10 . 
     Further, in the above-described embodiment, the recessed portion  10 F for accommodating the first link  651 , the second link  652 , and the connection bar  653  is positioned at the intermediate portion of the casing  10  in the first direction. As a modification, a corresponding recessed portion may be positioned closer to the one end portion in the first direction of the casing  10 , or closer to the other end portion in the first direction of the casing  10 . 
     In the above-described embodiment, the inner wall surface of the first guide recess  61   a  of the first shaft  61  serves to restrict a pivotally movable range of the first link  651 , and the inner wall surface of the second guide recess  62   a  of the second shaft  62  serves to restrict a pivotally movable range of the second link  652 . Alternatively, a regulation plate(s) contactable with the first link  651  and/or second link  652  may be positioned within the recessed portion  10 F so that the first link  651  and/or the second link  652  can contact the regulation plate(s) in order to regulate the pivotally movable ranges of the first link  651  and the second link  652 . 
     Note that the detailed configuration of the developing cartridge  1  may be different from that described above and illustrated in the drawings. Further, each component in the above-described embodiment and modifications may be suitably combined together as long as no technical conflicts is incurred.