Patent Publication Number: US-8983334-B2

Title: Image forming apparatus having a path regulating member

Description:
This application is a continuation of application Ser. No. 14/054,990, filed Oct. 16, 2013, which is a continuation of application Ser. No. 13/554,570, filed Jul. 20, 2012, now U.S. Pat. No. 8,666,278, issued Mar. 4, 2014, which is a continuation of International Application No. PCT/JP2011/068720, filed Aug. 12, 2011. 
    
    
     TECHNICAL FIELD 
     The present invention relates to an image forming apparatus such as a copying machine or a facsimile machine. 
     BACKGROUND ART 
     Heretofore, there has been an image forming apparatus of a process cartridge type in which a cartridge such as a drum cartridge provided with a photosensitive drum or a developing cartridge provided with a developing roller. For example, in U.S. Pat. No. 7,813,670, a door provided to an apparatus main assembly is opened and then the cartridge can be demounted. Further, the door is provided with a positioning urging portion for urging the cartridge in a closed state to position the cartridge in the apparatus main assembly. Such an image forming apparatus is capable of individually replacing (exchanging) the photosensitive drum and the developing roller and therefore is effective in such a case where a product lifetime is different between the photosensitive drum and the developing roller. 
     However, with downsizing of the image forming apparatus in recent years, there arises a need to suppress a height of the apparatus main assembly or a size of the image forming apparatus with respect to a widthwise direction. With the need, a path along which the cartridge is demounted from the apparatus main assembly is being narrowed. 
     In the U.S. Pat. No. 7,813,670, the cartridge demounting path become narrow with the downsizing of the apparatus, so that when the cartridge was demounted, the cartridge contacted the positioning urging portion of the door and thus there was a possibility that damage or breakage of the positioning urging portion was caused. 
     DISCLOSURE OF THE INVENTION 
     In an embodiment of the present invention, there is provided an image forming apparatus comprising: a main assembly of the image forming apparatus; a door openable with respect to the a main assembly of the image forming apparatus; a first cartridge detachably mountable to the main assembly of the image forming apparatus in a state in which the door is open; and a detachably mountable second cartridge provided above the first cartridge, wherein the door includes a contact portion contactable to the second cartridge in a state in which the door is closed, and wherein the door includes a mounting and demounting path regulating member for regulating the first cartridge so that the first cartridge passes along a non-interference path with the contact portion by being contacted to the first cartridge when the first cartridge is demounted from the image forming apparatus. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Part (a) of  FIG. 1  is a perspective view of an image forming apparatus according to First Embodiment. Part (b) of  FIG. 1  is an illustration of the image forming apparatus according to First Embodiment. 
         FIG. 2  is a perspective view of the image forming apparatus according to First Embodiment in a state in which a door is open. 
         FIG. 3  is a view for illustrating mounting and demounting of a developing cartridge according to First Embodiment. 
       Parts (a) and (b) of  FIG. 4  include perspective views of the image forming apparatus in a state in which the developing cartridges according to First Embodiment are demounted. 
       Parts (a) and (b) of  FIG. 5  include perspective views of the image forming apparatus in a state in which a cartridge according to First Embodiment is demounted. 
       Parts (a) and (b) of  FIG. 6  include perspective views of the developing cartridges according to First Embodiment. 
         FIG. 7  is a view for illustrating mounting and demounting of a drum cartridge according to First Embodiment. 
       Part (a) of  FIG. 8  is a left side view of the door according to First Embodiment. Part (b) of  FIG. 8  is a top plan view of the door according to First Embodiment. 
         FIG. 9  is a left side view of the door provided with a mounting and demounting path regulating member in another shape. 
       Parts (a) and (b) of  FIG. 10  include perspective views of the drum cartridge according to First Embodiment. 
         FIG. 11  is a top plan view of a clearance portion of the drum cartridge according to First Embodiment. 
       Part (a) of  FIG. 12  is a left side view of a door according to Second Embodiment. Part (b) of  FIG. 12  is a top plan view of the door according to Second Embodiment. 
         FIG. 13  is a top plan view of a drum cartridge according to Second Embodiment. 
       Part (a) of  FIG. 14  is a perspective view of developing cartridges according to Second Embodiment. Part (b) of  FIG. 14  is a top plan view of the developing cartridges according to Second Embodiment. 
       Part (a) of  FIG. 15  is a left side view of a drum cartridge according to Third Embodiment. Part (b) of  FIG. 15  is a front view of the drum cartridge according to Third Embodiment. 
       Part (a) of  FIG. 16  is a left side view of a door according to Third Embodiment. Part (b) of  FIG. 16  is a top plan view of the door according to Third Embodiment. 
       Parts (a) and (b) of  FIG. 17  are left side views each showing an embodiment of the drum cartridge according to Third Embodiment. 
       Part (a) of  FIG. 18  is a perspective view of an image forming apparatus according to Fourth Embodiment. Part (b) of  FIG. 18  is an illustration of the image forming apparatus according to Fourth Embodiment. 
         FIG. 19  is a perspective view of the image forming apparatus according to Fourth Embodiment in a state in which a door is open. 
         FIG. 20  is a view for illustrating mounting and demounting of an all-in-one cartridge according to Fourth Embodiment. 
         FIG. 21  includes perspective views of the image forming apparatus according to Fourth Embodiment in a state in which the all-in-one cartridge is demounted. 
       Part (a) of  FIG. 22  is a left side view of the door according to Fourth Embodiment. Part (b) of  FIG. 22  is a top plan view of the door according to Fourth Embodiment. 
         FIG. 23  includes perspective views of the all-in-one cartridge according to Fourth Embodiment. 
       Part (a) of  FIG. 24  is a left side view of a door according to Fifth Embodiment. Part (b) of  FIG. 24  is a top plan view of the door according to Fifth Embodiment. 
         FIG. 25  is a top plan view of an all-in-one cartridge according to Fifth Embodiment. 
       Part (a) of  FIG. 26  is a left side view of an all-in-one cartridge according to Sixth Embodiment. Part (b) of  FIG. 26  is a front view of the all-in-one cartridge according to Sixth Embodiment. 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     First Embodiment 
     First Embodiment of an image forming apparatus according to the present invention will be described with reference to the drawings. 
     (Brief Description of Image Forming Apparatus  100 ) 
     Part (a) of  FIG. 1  is a perspective view of the image forming apparatus according to this embodiment. Part (b) of  FIG. 1  is an illustration of the image forming apparatus according to this embodiment. 
     As shown in  FIG. 1 , the image forming apparatus  100  in this embodiment includes developing cartridges (second cartridge)  4   y ,  4   m ,  4   c  and  4   k  and a drum cartridge (first cartridge)  8 . As shown in  FIG. 3 , the developing cartridges  4   y - 4   k  are detachably mounted to a developing cartridge mounting and demounting portion  102  of an image forming apparatus main assembly  101  in a state in which a door  10  is open. As shown in  FIG. 4 , the drum cartridge  8  is, after the developing cartridges  4   y - 4   k  are demounted in the state in which the portion  10  is open, detachably mounted to a drum cartridge mounting and demounting portion  104  (see (a) of  FIG. 5 ). 
     The drum cartridge  8  includes a photosensitive drum (photosensitive member)  1 . The photosensitive drum  1  is electrically charged by a charger  2  at its drum surface and is exposed to laser light L on the basis of image information by an exposure device  3 , so that an electrostatic latent image is formed. The electrostatic latent image is developed, with toner of each of colors of yellow, magenta, cyan and black, as a toner image of each color by the developing cartridges  4   y - 4   k . The developed toner image is primary-transferred onto an intermediary transfer belt  51  of an intermediary transfer unit  5 . The transfer residual toner remaining on the photosensitive drum  1  after the primary transfer is cleaned (removed) by a drum cleaning device  6 . 
     On the other hand, a sheet S stacked in a feeding cassette  17  is conveyed to a nip between a secondary transfer roller  32  and the intermediary transfer belt  51  by a feeding roller  18  and a registration roller pair  19 , so that the toner image primary-transferred on the intermediary transfer belt  51  is secondary-transferred. The sheet S on which the toner image is transferred is subjected to fixing of the toner image by a fixing portion  20  and is discharged to the outside of the apparatus main assembly by a discharging roller pair  23 . A transfer residual toner remaining on the intermediary transfer belt  51  is cleaned (removed) by a belt cleaning device  7 . 
     (Exchange Type of Developing Cartridges  4   y - 4   k ) 
     At a front surface of the apparatus main assembly  101 , an opening  103  is provided. The door  10  is rotationally moved about a hinge shaft  10   b  as the center in a door lower edge side, thus being capable of opening and closing the opening  103 . By opening the door  10  by holding a handle  10   a  provided to the door  10 , as shown in  FIG. 2 , the developing cartridge mounting and demounting portion  102  is opened. 
     As shown in  FIG. 5 , four sets of guide rails  25 R and  25 L extending in the horizontal direction are oppositely provided on inner wall surfaces of a right-side frame  105 R and a left-side frame  105 L of the apparatus main assembly  101 . As shown in  FIG. 6 , portions to be guided  4 Ra and  4 La are provided at left-side surface portions and right-side surface portions of the developing cartridges  4   y - 4   k , respectively. Projections to be guided  4 Ra and  4 La slide on the guide rails  25 R and  25 L in the horizontal direction (arrow X1 and X2 directions), so that the developing cartridges  4   y - 4   k  are detachably mountable to the developing cartridge mounting and demounting portion  102 . 
     As shown in  FIG. 5 , on an inner surface  10   c  of the door  10  in the inside, positioning urging portions (contact portion)  26  are provided. The urging portions  26  urge the developing cartridges  4   y - 4   k  in a direction (arrow X2 direction) in which the cartridges are pushed in the developing cartridge mounting and demounting portion  102 , thus positioning the developing cartridges  4   y - 4   k  in the apparatus main assembly  101 . 
     (Exchange Type of Drum Cartridge  8 ) 
     As shown in  FIG. 7 , the drum cartridge  8  is demounted and mounted as described above in the state in which the portion  10  is opened and the developing cartridges  4   y - 4   k  are demounted. The drum cartridge  8  is guided, by left and right guide rails  27 R and  27 L provided on the bottom of the apparatus main assembly  101 , in a demounting direction (X1 direction) or a mounting direction (X2 direction), thus being demounted from and mounted and the drum cartridge mounting and demounting portion  104 . 
     (Drum Cartridge Mounting and Demounting Guide  28 ) 
     As shown in  FIGS. 2 ,  5 ,  7  and  8 , on the inner surface  10   c  of the door  10 , drum cartridge mounting and demounting guides (mounting and demounting path regulating member)  28 R and  28 L are provided in left and right sides, respectively. 
     The drum cartridge mounting and demounting guides  28 R and  29 L are provided so that positions thereof are closer toward the door than a position of gravitation of the developing cartridges  4   y - 4   k  with respect to the demounting direction when the developing cartridges  4   y - 4   k  are located in the image forming apparatus main assembly. The mounting and demounting guides  28 R and  28 L are provided apart from each other with a distance not more than a width of the drum cartridge  8  with respect to the widthwise direction (arrow X4 direction). 
     The mounting and demounting guides  28 R and  28 L have an inclined surface  28   a  inclined upward with respect to a drum cartridge demounting direction (X1 direction) in the state in which the door  10  is open. Incidentally, as shown in  FIG. 9 , the inclined surface  28   a  may also be a curved surface if it is a gentle surface (slope). Further, the inclined surface  28   a  may also be constituted by an inclined surface and a curved surface. The mounting and demounting guides  28 R and  28 L have the same shape as seen from a left side surface direction as shown in (a) of  FIG. 8  and are provided at the same position with respect to the demounting direction (X1 direction). For this reason, the drum cartridge  8  simultaneously contacts the mounting and demounting guides  28 R and  28 L. As a result, inclination of the drum cartridge  8  can be suppressed. 
     As shown in (a) of  FIG. 8 , the mounting and demounting guides  28 R and  28 L are, in the state in which the door  10  is open, provided closer to the inside of the apparatus main assembly than contact points (contact portions)  15  to be contacted to the contact points  14  (see  FIG. 6 ) of the developing cartridges  4   y - 4   k  and than the urging portions  26 . The developing cartridges  4   y - 4   k  are capable of being supplied with electric power from the apparatus main assembly via the contact points  14  and are operated by receiving electric signals. The contact points  15  and the urging portions  26  are projected from the door  10 . Further, the mounting and demounting guides  28 R and  28 L are, when the door  10  is viewed from the left side surface direction, higher than the contact points  15  and the urging portions  26  (height in arrow X3 direction). 
     During the demounting of the drum cartridge  8  from the apparatus main assembly  101 , when the drum cartridge  8  located at the drum cartridge mounting and demounting portion  104  is pulled out, a lower end of the drum cartridge  8  contacts the inclined surfaces  28   a  of the mounting and demounting guides  28 R and  28 L. Then, the drum cartridge  8  is moved along the inclined surfaces  28   a  in a direction in which it is moved away from the contact points  15  and the urging portions  26 , so that the drum cartridge  8  is prevented from contacting the contact points  15  and the urging portions  26 . 
     Thus, the mounting and demounting guides  28 R and  28 L regulate the drum cartridge  8  so as to pass along non-interference path (pass in which they do not interfere) with the contact points  15  and the urging portions  26 . As a result, when the drum cartridge  8  is demounted from the downsized image forming apparatus  100 , contact of the mounting and demounting guides  28 R and  28 L to the contact points  15  and the urging portions  26  is suppressed, so that damage and breakage of the contact points  15  and the urging portions  26  can be suppressed. 
     Incidentally, the mounting and demounting guides  28 R and  28 L are not limited to two but may also be one or three or more. Further, the width of the mounting and demounting guides  28 R and  28 L (width with respect to arrow X4 direction) is not particularly defined but is set at a width capable of maintaining a strength of not less than a certain level so that the mounting and demounting guides  28 R and  28 L are not broken even when they are contacted to the drum cartridge  8  when the drum cartridge  8  is demounted. 
     Incidentally, in this embodiment, the mounting and demounting guides  28 R and  28 L were described as members for regulating the drum cartridge  8 . However, in the present invention, a member to be regulated by the mounting and demounting guides  28 R and  28 L is not limited to the drum cartridge  8  but may also be the cartridges, such as the developing cartridges  4   y - 4   k , detachably mountable to the apparatus main assembly. That is, a constitution in which when the developing cartridges  4   y - 4   k  are demounted from the apparatus main assembly  101 , the mounting and demounting guides  28 R and  28 L contact the developing cartridges  4   y - 4   k  or the like to suppress contact of the developing cartridges  4   y - 4   k  to the contact points  15  and the urging portions  26  may only be required. 
     As shown in  FIGS. 10 and 11 , the drum cartridge  8  includes a pulling-out member  8   c , extending to a side close to the opening  103 , provided with a handle  8   a  and left and right clearance portions  8 Rd and  8 Ld. The clearance portions  8 Rd and  8 Ld are provided by being formed in a shape such that they are recessed from an end portion of the drum cartridge  8  in the side close to the door  10 . By providing the handle  8   a  at a surface in the side close to the opening  103 , the drum cartridge  8  can be easily demounted. 
     A width of the clearance portions  8 Rd and  8 Ld with respect to the X4 direction is larger than a width of the mounting and demounting guides  28 R and  28 L with respect to the arrow X4 direction. Further, a width of the clearance portions  8 Rd and  8 Ld with respect to the X1 direction is larger than a height of the mounting and demounting guides  28 R and  28 L with respect to the arrow X3 direction. As a result, when the door  10  is closed, the mounting and demounting guides  28 R and  28 L can pass through the clearance portions  8 Rd and  8 Ld, so that the mounting and demounting guides  28 R and  28 L and the drum cartridge  8  are prevented from interfering with each other. 
     Second Embodiment 
     Next, Second Embodiment of an image forming apparatus according to the present invention will be described with reference to the drawings. Portions of redundancy in description with the above-described First Embodiment will be omitted from description by adding the same reference numerals or symbols. Part (a) of  FIG. 12  is a side view of the door  10  according to this embodiment. Part (b) of  FIG. 12  is a plan view of the door  10  according to this embodiment. 
     As shown in  FIG. 12 , in the image forming apparatus in this embodiment, in place of the drum cartridge mounting and demounting guides  28 R and  28 L of the image forming apparatus in the above-described First Embodiment, drum cartridge mounting and demounting guides  30 R and  30 L are provided. The mounting and demounting guides  30 R and  30 L are obtained by extending the mounting and demounting guides  28 R and  28 L in the pulling-out direction (arrow X1 direction). During the mounting and demounting of the drum cartridge  8 , with respect to the pulling-out direction in which the drum cartridge  8  is demounted, first surface portions  30   b  of the mounting and demounting guides  30 R and  30 L have a length in which all of four contact points  15  and four urging portions  26  are covered. 
     The drum cartridge mounting and demounting guides  30 R and  30 L are provided outside the contact points  15  and the urging portions  26  with respect to the widthwise direction (arrow X4 direction) but may also be provided inside. The mounting and demounting guides  30 R and  30 L are provided apart from each other with a distance not more than a width of the drum cartridge  8  with respect to the widthwise direction (arrow X4 direction). 
     The mounting and demounting guides  30 R and  30 L have the same shape and are provided at the same position with respect to the demounting direction (X1 direction). For this reason, the drum cartridge  8  simultaneously contacts the mounting and demounting guides  30 R and  30 L. As a result, inclination of the drum cartridge  8  can be suppressed. 
     The mounting and demounting guides  30 R and  30 L have an inclined surface  30   a  inclined upward with respect to a drum cartridge demounting direction (X1 direction) in the state in which the door  10  is open. The mounting and demounting guides  30 R and  30 L are higher than the contact points  15  and the urging portions  26  with respect to the arrow X3 direction. 
     During the demounting of the drum cartridge  8  from the apparatus main assembly  101 , when the drum cartridge  8  located at the drum cartridge mounting and demounting portion  104  is pulled out, a lower end of the drum cartridge  8  contacts the inclined surfaces  30   a  of the mounting and demounting guides  30 R and  30 L. Then, the drum cartridge  8  is moved upward (in a direction in which it is moved away from the inner surface  10   c  of the door  10 ) along the inclined surfaces  30   a  and is pulled out by being guided by flat surface portions  30   b . For this reason, the drum cartridge  8  is prevented from contacting the contact points  15  and the urging portions  26 . 
     As a result, similarly as in the above-described First Embodiment, when the drum cartridge  8  is demounted from the downsized image forming apparatus  100 , contact of the mounting and demounting guides  28 R and  28 L to the contact points  15  and the urging portions  26  is suppressed, so that damage and breakage of the contact points  15  and the urging portions  26  can be suppressed. 
     Further, by providing the flat surface portions  30   b , the drum cartridge  8  can be further stably mounted and demounted, so that a possibility that the drum cartridge  8  runs against the contact points  15  and the urging portions  26  can be further reduced. 
     As shown in  FIG. 13 , the drum cartridge  8  is changed in constitution from the clearance portions in the above-described First Embodiment. The clearance portions  8 Re and  8 Le are constituted so that the mounting and demounting guides  30 R and  30 L can pass through the clearance portions  8 Rd and  8 Ld when the door  10  is closed, so that the mounting and demounting guides  30 R and  30 L and the drum cartridge  8  are prevented from interfering with each other. 
     As shown in  FIG. 14 , the developing cartridges  4   y - 4   k  in this embodiment includes the clearance portions  4 Rb and  4 Lb at an outer surface of the apparatus main assembly in a state in which they are mounted in the apparatus main assembly. The clearance portions  4 Rb and  4 Lb are constituted so that the mounting and demounting guides  30 R and  30 L passes through the clearance portions  4 Rb and  4 Lb when the door  10  is closed to prevent the mounting and demounting guides  30 R and  30 L and the developing cartridges  4   y - 4   k  from interfering with each other. 
     Third Embodiment 
     Next, Third Embodiment of an image forming apparatus according to the present invention will be described with reference to the drawings. Portions of redundancy in description with the above-described First or Second Embodiment will be omitted from description by adding the same reference numerals or symbols. Part (a) of  FIG. 15  is a side view of the drum cartridge  8  according to this embodiment. Part (b) of  FIG. 15  is a plan view of the drum cartridge  10  according to this embodiment. 
     (Drum Cartridge Leg Portions  8 Rf and  8 Lf) 
     As shown in  FIG. 15 , in the image forming apparatus in this embodiment, the position where the drum cartridge mounting and demounting guides  28 R and  28 L are provided is changed from the door inner surface  10   c  to a drum cartridge lower surface  8   e  and the mounting and demounting guides  28 R and  28 L are changed to drum cartridge positions  8 Rf and  8 Lf. The drum cartridge leg portions  8 Rf and  8 Lf are provided in a side close to the door  10  when the drum cartridge  8  is mounted in the apparatus main assembly  101 . Incidentally, in this embodiment, in (a) of  FIG. 15 , the positions  8 Rf and  8 Lf are provided at a position which coincides with an end portion of the demounting direction (X1 direction) of the drum cartridge  8  but may also be provided at different positions if the positions are a position where the inclination of the drum cartridge  8  can be prevented when the drum cartridge  8  is pulled out from the apparatus main assembly  101 . 
     A height of the drum cartridge leg portions  8 Rf and  8 Lf with respect to the X3 direction is made large compared with the contact points  15  and the urging portions  26  so that the drum cartridge leg portions  8 Rf and  8 Lf do not contact the contact points  15  and the positioning urging portions  26  on the door when the drum cartridge  8  is inclined and is supported by the drum cartridge leg portions  8 Rf and  8 Lf. 
     When the drum cartridge leg portions  8 Rf and  8 Lf are mounted in the apparatus main assembly  101 , leg portion lower surfaces  8 Rg and  8 Lg contacting the door inner surface  10   c  are flat surfaces parallel to the bottom surface  8   e  of the drum cartridge  8 . Incidentally, when the drum cartridge  8  is pulled out from the apparatus main assembly  101 , if the drum cartridge  8  can be supported without being inclined, the leg portion lower surfaces  8 Rg and  8 Lg are not required to be the flat surfaces parallel to the bottom surface  8   e  but may also be, e.g., curved surfaces. 
     As shown in (b) of  FIG. 15 , a distance between the drum cartridge leg portions  8 Rf and  8 Lf is larger than a width of the hinge shaft  10   b  of the door  10  with respect to the X4 direction. Incidentally, in this embodiment, the leg portions  8 Rf and  8 Lf are two but may also be one, or three or more if they have a structure in which they do not contact the hinge shaft  10   b  of the door  10  when the drum cartridge  8  is demounted from the apparatus main assembly  101 . Further, the hinge shaft of the door  10  may also be two or more. 
     The drum cartridge leg portion  8 Rf is, when the drum cartridge  8  is viewed from the front direction, provided in the right side of the position of the positioning urging portions  26  and is provided so that its right end coincides with the right end of the drum cartridge  8 . Further, a width of the leg portion  8 Rf with respect to the X4 direction is not particularly defined but is a width with which the leg portion  8 Rf can have a strength at a certain level or more capable of supporting the drum cartridge  8  when the drum cartridge  8  is inclined. 
     Incidentally, the right end of the leg portion  8 Rf coincides with the right end of the drum cartridge  8  but may also not coincide with the right end of the drum cartridge  8  if the drum cartridge  8  can be supported without being inclined. Further, in this embodiment, when the drum cartridge  8  is mounted in the apparatus main assembly  101 , the position  8 Rf is disposed in the right side of the urging portions  26  but may also be disposed in the left side of the urging portions  26  if the drum cartridge  8  can be supported without being inclined. 
     The drum cartridge leg portion  8 Lf is, when the drum cartridge  8  is viewed from the front direction, provided in the left side of the position of the contact points  15  and is provided so that its left end coincides with the left end of the drum cartridge  8 . Further, a width of the leg portion  8 Lf with respect to the X4 direction is not particularly defined but is a width with which the leg portion  8 Lf can have a strength at a certain level or more capable of supporting the drum cartridge  8  when the drum cartridge  8  is inclined. 
     Incidentally, the left end of the leg portion  8 Lf coincides with the left end of the drum cartridge  8  but may also not coincide with the right end of the drum cartridge  8  if the drum cartridge  8  can be supported without being inclined. Further, in this embodiment, when the drum cartridge  8  is mounted in the apparatus main assembly  101 , the position  8 Lf is disposed in the left side of the contact points  15  but may also be disposed in the right side of the contact points  15  if the drum cartridge  8  can be supported without being inclined. 
     The drum cartridge  8  is, immediately before and after being demounted from the apparatus main assembly  101 , supported in contact to the apparatus main assembly  101  at its lower surface  8   e  but when it is demounted to some extent, the center of gravity of the drum cartridge is moved relative to the image forming apparatus main assembly and the drum cartridge  8  is inclined by its own weight and therefore, a part of the lower surface  8   e  contacts the apparatus main assembly  101  and the drum cartridge leg portion lower surfaces  8 Rg and  8 Lg contact the door inner surface  10   c , so that the drum cartridge  8  is supported. At this time, as described above, the height of the drum cartridge leg portions  8 Rf and  8 Lf with respect to the X3 direction is large compared with the contact points  15  and the positioning urging portions  26  and therefore when the drum cartridge  8  is demounted from the apparatus main assembly  101 , it is possible to avoid contact of the main assembly of the drum cartridge  8  to the contact points  15  and the positioning urging portions  26 . 
     Incidentally, as shown in (a) of  FIG. 15 , the drum cartridge leg portions  8 Rf and  8 Lf are provided in a pair at the end portion of the lower surface  8   e  with respect to the demounting direction (X1 direction) but may be further provided in a pair also at the end portion with respect to the mounting direction (X2 direction) as shown in (a) of  FIG. 17 . By this constitution, during the demounting of the drum cartridge  8  from the apparatus main assembly  101 , when the drum cartridge  8  is demounted to some extent or more, the leg portions  8 Rf and  8 Lf at the end portion with respect to the demounting direction (X1 direction) are separated from the door surface  11   c  and therefore cannot support the drum cartridge  8  but the positions  8 Rf and  8 Lf at the end portion with respect to the mounting direction (X2 direction) can support the drum cartridge  8  and therefore, it is possible to further avoid the contact of the drum cartridge  8  to the contact points  15  and the urging portions  26 . 
     Further, a width of the drum cartridge leg portions  8 Rf and  8 Lf with respect to the X1 direction is not particularly defined if the drum cartridge  8  can be supported without being inclined, but as shown in (b) of  FIG. 17 , the leg portions  8 Rf and  8 Lf are extended from the end portion with respect to the demounting direction (X1 direction) to the end portion with respect to the mounting direction (X2 direction), so that similarly as in the above-described constitution, it is possible to more avoid the contact of the drum cartridge  8  to the contact points  15  and the urging portions  26 . 
     Incidentally, a member defined by the drum cartridge leg portions  8 Rf and  8 Lf shown in this embodiment is not limited to the drum cartridge  8  as in this embodiment but may also be another cartridge such as the developing cartridges or the like if the cartridge is detachably mountable to the apparatus main assembly  101 . 
     (Constitution Example of Portion) 
     In this embodiment, shapes of the door  10  and the door  10   b  are partly changed. 
     As shown in  FIG. 16 , the hinge shaft  10   b  of the door  10  is disposed at the central portion of the door  10  with respect to the X4 direction, so that the door  10  is openable with respect to the apparatus main assembly  101 . Incidentally, in this embodiment, the hinge shaft  10   b  is one but may also be disposed at a position other than the central portion and may also be two or more if it has a structure which does not interfere with the drum cartridge leg portions  8 Rf and  8 Lf. 
     Fourth Embodiment 
     Next, Fourth Embodiment of an image forming apparatus according to the present invention will be described with reference to the drawings. Portions of redundancy in description with the above-described First to Third Embodiments will be omitted from description by adding the same reference numerals or symbols. Part (a) of  FIG. 18  is a perspective view of the image forming apparatus according to this embodiment. Part (b) of  FIG. 18  is an illustration of the image forming apparatus according to this embodiment. 
     As shown in  FIG. 18 , the image forming apparatus in this embodiment includes an all-in-one cartridge (process cartridge) including a positioning device and a drum. As shown in  FIG. 18 , the all-in-one cartridge  9  is detachably mounted to an all-in-one cartridge mounting and demounting portion  106  of an image forming apparatus main assembly  101  in a state in which a door  10  is open. 
     The all-in-one cartridge  9  includes a photosensitive drum  1 . The photosensitive drum  1  is electrically charged by a charger  2  at its drum surface and is exposed to laser light L on the basis of image information by an exposure device  3 , so that an electrostatic latent image is formed. The electrostatic latent image is developed, with a toner of black, as a toner image of each color a developing roller  4   a.    
     On the other hand, a sheet S stacked in a feeding cassette  17  is conveyed to a nip between a transfer roller  32  and the photosensitive drum  1  by a feeding roller  18  and a registration roller pair  19 , so that the toner image transferred on the photosensitive drum  1  is transferred. The sheet S on which the toner image is transferred is subjected to fixing of the toner image by a fixing portion  20  and is discharged to the outside of the apparatus main assembly by a discharging roller pair  23 . A transfer residual toner remaining on the photosensitive drum  1  is cleaned (removed) by a drum cleaning device  6 . 
     (Exchange Type of all-in-One Cartridge  9 ) 
     By opening the door  10  by holding a handle  10   a  provided to the door  10 , an opening  103  is opened and as shown in  FIG. 19 , the all-in-one cartridge mounting and demounting portion  106  is opened. 
     As shown in  FIG. 20 , the all-in-one cartridge  9  is mounted and demounted in the state in which the door  10  is open as described above. The all-in-one cartridge  9  is guided by left and right guide rails  27 R and  27 L provided on the bottom of the apparatus main assembly  101  with respect to a demounting direction (X1 direction) or a mounting direction, thus being mounted to end demounted from the all-in-one cartridge mounting and demounting portion  106 . 
     As shown in  FIG. 21 , on an inner surface  10   c  of the door  10 , positioning urging portions (contact portion)  26  are provided. The urging portions  26  urge the all-in-one cartridge  9  in a direction (arrow X2 direction) in which the all-in-one cartridge  9  is pushed in the all-in-one cartridge mounting and demounting portion  106 , thus positioning the developing cartridges  4   y - 4   k  in the apparatus main assembly  101 . 
     (Exchange Type of Drum Cartridge  8 ) 
     As shown in  FIG. 7 , the drum cartridge  8  is demounted and mounted as described above in the state in which the portion  10  is opened and the developing cartridges  4   y - 4   k  are demounted. The drum cartridge  8  is guided, by left and right guide rails  27 R and  27 L provided on the bottom of the apparatus main assembly  101 , in a demounting direction (X1 direction) or a mounting direction (X2 direction), thus being demounted from and mounted and the drum cartridge mounting and demounting portion  104 . 
     (All-in-One Cartridge Mounting and Demounting Guide  28 ) 
     As shown in  FIGS. 19 ,  21  and  22 , on the inner surface  10   c  of the door  10 , all-in-one cartridge mounting and demounting guides (mounting and demounting path regulating member)  28 R and  28 L are provided in left and right sides, respectively. The all-in-one cartridge mounting and demounting guides  28 R and  28 L change the object to be guided from the drum cartridge  8  in the above-described First Embodiment to the all-in-one cartridge  9  but the constitution thereof is the same as that of the drum cartridge mounting and demounting guides  28 R and  28 L. Incidentally, also with respect to an object of the effect in this embodiment, the object is changed from the drum cartridge  8  to the all-in-one cartridge  9  but the contents of the effect are the same as those in First Embodiment. 
     As shown in  FIG. 23 , the all-in-one cartridge  9  includes a pulling-out member  9   a , extending to a side close to the opening  103 , provided with a handle  9   b  and left and right clearance portions  9 Rd and  9 Ld. By providing the handle  9   b  at a surface in the side close to the opening  103 , the all-in-one cartridge  9  can be easily demounted. Further, a width of the clearance portions  9 Rd and  9 Ld with respect to the X4 direction is larger than a width of the mounting and demounting guides  28 R and  28 L with respect to the arrow X4 direction. Further, a width of the clearance portions  9 Rd and  9 Ld with respect to the X1 direction is larger than a height of the mounting and demounting guides  28 R and  28 L with respect to the arrow X3 direction. As a result, when the door  10  is closed, the mounting and demounting guides  28 R and  28 L can pass through the clearance portions  9 Rd and  9 Ld, so that the mounting and demounting guides  28 R and  28 L and the all-in-one cartridge  9  are prevented from interfering with each other. 
     Fifth Embodiment 
     Next, Fifth Embodiment of an image forming apparatus according to the present invention will be described with reference to the drawings. Portions of redundancy in description with the above-described First to Fourth Embodiments will be omitted from description by adding the same reference numerals or symbols. 
     As shown in  FIG. 24 , in the image forming apparatus in this embodiment, in place of the all-in-one cartridge mounting and demounting guides  28 R and  28 L of the image forming apparatus in the above-described Fourth Embodiment, all-in-one cartridge mounting and demounting guides  30 R and  30 L are provided. Further, the all-in-one cartridge mounting and demounting guides  30 R and  30 L change the object to be guided from the drum cartridge  8  in the above-described Second Embodiment to the all-in-one cartridge  9  but the constitution thereof is the same as that of the drum cartridge mounting and demounting guides  28 R and  28 L. Incidentally, also with respect to an object of the effect in this embodiment, the object is changed from the drum cartridge  8  to the all-in-one cartridge  9  but the contents of the effect are the same as those in Second Embodiment. 
     As shown in  FIG. 25 , the all-in-one cartridge  9  changes the constitution from the clearance portions in the above-described Fourth Embodiment. The clearance portions  9 Re and  9 Le are constituted so that the mounting and demounting guides  30 R and  30 L can pass through the clearance portions  9 Re and  9 Le when the door  10  is closed, so that the mounting and demounting guides  30 R and  30 L and the all-in-one cartridge  9  are prevented from interfering with each other. 
     Sixth Embodiment 
     Next, a Sixth Embodiment of an image forming apparatus according to the present invention will be described with reference to the drawings. Portions of redundancy in the description with the above-described First to Fifth Embodiments will be omitted from the description by adding the same reference numerals or symbols. Part (a) of  FIG. 26  is a side view of the all-in-one cartridge  9  according to this embodiment. Part (b) of  FIG. 26  is a front view of the all-in-one cartridge  9  according to this embodiment. 
     (All-in-one cartridge leg portions  9 Rf and  9 Lf) 
     As shown in  FIG. 25 , in the image forming apparatus in this embodiment, the position where the all-in-one cartridge mounting and demounting guides  30 R and  30 L are provided is changed from the door inner surface  10   c  to a all-in-one cartridge lower surface  9   e  and the mounting and demounting guides  30 R and  30 L are changed to drum cartridge leg portions  9 Rf and  9 Lf. Further, the object to be guided from the drum cartridge  8  in the above-described Third Embodiment to the all-in-one cartridge  9  but the constitution thereof is the same as that of the drum cartridge leg portions  8 Rf and  8 Lf. Incidentally, also with respect to an object of the effect in this embodiment, the object is changed from the drum cartridge  8  to the all-in-one cartridge  9  but the contents of the effect are the same as those in Third Embodiment. 
     As described above, by the constitutions of the above-described Embodiments 1 to 6, even when a path along which the cartridge is demounted from the apparatus main assembly is narrowed with downsizing of the image forming apparatus, a user can easily demount the cartridge from the apparatus main assembly without breaking the urging portions and the contact points on the door. 
     INDUSTRIAL APPLICABILITY 
     As described above, according to the present invention, there is provided the image forming apparatus capable of suppressing the contact of the cartridge to the positioning urging portions of the door when the cartridge is demounted from the downsized image forming apparatus and thus capable of suppressing the damage and breakage of the positioning urging portions.