Patent Publication Number: US-9429897-B2

Title: Image forming apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2014-206277 filed Oct. 7, 2014. 
     BACKGROUND 
     Technical Field 
     The present invention relates to an image forming apparatus. 
     SUMMARY 
     According to an aspect of the invention, there is provided an image forming apparatus including an image carrier that is rotatably supported, a to-be-transferred member onto which an image that is held by the image carrier is transferred, a driving unit that is disposed on a first end portion of the image carrier in an axial direction of the image carrier and that causes the image carrier to rotate, and a retreat mechanism that causes a second end portion of the image carrier to be separated from the to-be-transferred member while a connection between the image carrier and the driving unit is maintained and thereafter causes the image carrier to retreat by disconnecting the image carrier and the driving unit from each other. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       An exemplary embodiment of the present invention will be described in detail based on the following figures, wherein: 
         FIG. 1  is a sectional side view of an image forming apparatus according to an exemplary embodiment; 
         FIG. 2  is a perspective view illustrating a state where an opening and closing portion of the image forming apparatus according to the exemplary embodiment is open; 
         FIG. 3A  is a front view illustrating a mounting position where a process cartridge is in a state of being mounted in an image forming apparatus body,  FIG. 3B  is a front view illustrating a state where the process cartridge is located at a retreat position, and  FIG. 3C  is a front view illustrating a state where the process cartridge is removed from the image forming apparatus body; 
         FIG. 4A  is a sectional view illustrating a connecting portion and a to-be-connected portion in a state where the process cartridge is located at the mounting position,  FIG. 4B  is a sectional view illustrating the connecting portion and the to-be-connected portion in a state where the process cartridge is located at the retreat position, and  FIG. 4C  is a sectional view illustrating the connecting portion and the to-be-connected portion in a state where the process cartridge is removed from the image forming apparatus body; 
         FIG. 5A  is a cross-sectional view taken along line VA-VA of  FIG. 4A , and  FIG. 5B  is a cross-sectional view taken along line VB-VB of  FIG. 4B ; and 
         FIG. 6A  is a front view illustrating a state where the process cartridge is inserted into the image forming apparatus body,  FIG. 6B  is a sectional view illustrating a state where the process cartridge is located at the retreat position, and  FIG. 6C  is a front view illustrating a state where the process cartridge is mounted in the image forming apparatus body and located at the mounting position. 
     
    
    
     DETAILED DESCRIPTION 
     An exemplary embodiment of the present invention will be described below with reference to the drawings. However, in the exemplary embodiment, an image forming apparatus is descried as an example for implementing the technical concept of the present invention, and the present invention is not intended to be limited to the exemplary embodiment. The present invention is equally applicable to other exemplary embodiments within the scope of the claims. 
     Exemplary Embodiment 
     An image forming apparatus  10  according to an exemplary embodiment of the present invention, the image forming apparatus  10  including a retreat mechanism  109  for a process cartridge  30 , will be described with reference to  FIG. 1  to  FIG. 6C . 
     The image forming apparatus  10  includes an image forming apparatus body  12 , and an ejection part  14  is formed in a top surface of the image forming apparatus body  12 . A recording medium on which an image has been formed is to be ejected to the ejection part  14 . 
     As illustrated in  FIG. 2 , an opening  102  through which the process cartridge  30 , which will be described later, is to be mounted on and removed from the image forming apparatus body  12  is formed in one of side surfaces of the image forming apparatus body  12 , and an opening and closing portion  104  is formed in the one of side surfaces of the image forming apparatus body  12  so as to be capable of being opened and closed with respect to the image forming apparatus body  12  and allowing the opening  102  to be exposed or covered by the opening and closing portion  104 . The opening  102  is used as an area where an insertion operation is performed, and the process cartridge  30  is mounted by being inserted into the image forming apparatus body  12  from the opening  102 . The image forming apparatus  10  according to the exemplary embodiment is provided with the retreat mechanism  109  that causes the process cartridge  30  to retreat. 
     The retreat mechanism  109  is a mechanism that causes the process cartridge  30  to retreat from the image forming apparatus body  12 . The retreat mechanism  109  is configured to change the position of the process cartridge  30  between a mounting position where the process cartridge  30  is located when the process cartridge  30  is in a state of being mounted in the image forming apparatus body  12  and a retreat position where the process cartridge  30  is located when the process cartridge  30  is removed from the image forming apparatus body  12 , and the position of the process cartridge  30  is changed from the mounting position to the retreat position by changing only the position of a portion of the process cartridge  30  on one side. Note that the retreat mechanism  109  according to the exemplary embodiment is formed of a raising and lowering unit  136  that is attached to the process cartridge  30 , which will be described later, a to-be-connected portion  122  of a photoconductor  42 , and a connecting portion  112  included in a driving unit  110  that is attached to the image forming apparatus body  12  (see  FIGS. 3A to 3C  and  FIGS. 6A to 6C ). 
     An image forming unit  20  that forms an image, which is transferred onto a recording medium, a recording-media feeder  22  that feeds a recording medium to the image forming unit  20 , and a transport path  24  along which a recording medium, which is fed from the recording-media feeder  22 , is transported to the ejection part  14  are disposed in the image forming apparatus body  12 . In addition, a guiding portion  106  is disposed in the image forming apparatus body  12 , and the guiding portion  106  guides the process cartridge  30 , which is to be inserted into and removed from the image forming apparatus body  12  so as to be mounted on and removed from the image forming apparatus body  12 . 
     When the process cartridge  30  is mounted in the image forming apparatus body  12 , the process cartridge  30  is supported by the raising and lowering unit  136 , which is attached to the process cartridge  30  (see  FIG. 3A ). In this state, in the image forming apparatus body  12 , a portion where the raising and lowering unit  136  is positioned serves as a support portion  108 . 
     The image forming unit  20  includes, for example, process cartridges  30 Y,  30 M,  30 C, and  30 K that correspond to four colors of yellow (Y), magenta (M), cyan (C), and black (K), respectively, an optical writing device  32 , and a transfer device  34 . The configurations of the process cartridges  30 Y,  30 M,  30 C, and  30 K including their components are similar to one another except for colors of images formed by the process cartridges  30 Y,  30 M,  30 C, and  30 K. In the following description, the suffixes Y, M, C, and K may sometimes be omitted when it is not necessary to distinguish the process cartridges  30 Y,  30 M,  30 C, and  30 K and their components in accordance with the colors, and the process cartridges  30 Y,  30 M,  30 C, and  30 K may sometimes be collectively called, for example, “process cartridges  30 ”. 
     Each of the process cartridges  30  is used as a replaceable member and disposed so as to be capable of being mounted on and removed from the image forming apparatus body  12 . The process cartridges  30 Y,  30 M,  30 C, and  30 K are disposed in this order starting from the rear side (the left side in  FIG. 1 ) of the image forming apparatus body  12 . 
     Each of the process cartridges  30  is, for example, a device that employs an electrophotographic system and forms a color image. Each of the process cartridges  30  includes a process cartridge body  40 . In the process cartridge body  40 , the photoconductor  42  that serves as a drum-shaped image carrier, which carries a developer image, a charging device  44  that serves as a charging unit, which includes a charging roller that uniformly charges the photoconductor  42 , a developing unit  46  that develops a latent image, which has been written on the photoconductor  42 , with a developer (toner), and a cleaning device  48  that cleans the photoconductor  42  by, for example, scraping off waste developer remaining on the photoconductor  42  are disposed. 
     In order to cause the photoconductors  42  to rotate, the to-be-connected portions  122  that are configured to transmit the power of the driving units  110  and that are to be connected to the connecting portions  112 , which are included in the driving units  110 , are formed at first ends of the photoconductors  42 . Note that, in the exemplary embodiment, the to-be-connected portions  122  are formed in portions of the process cartridges  30  that are to be inserted into the image forming apparatus body  12 . 
     Gear portions  123  each having a cylindrical shape are formed in the to-be-connected portions  122 , which are formed at the first ends of the photoconductors  42 , and each of the gear portions  123  has plural first protrusions  124  protruding in an outward radial direction with respect to the axial direction of the corresponding photoconductor  42  (see  FIGS. 5A and 5B ). Note that second ends of the photoconductors  42  on the opposite side to the to-be-connected portions  122  serve as non-driving units  132  that extend from the second ends of the photoconductors  42 , and the non-driving units  132  are not connected to driving power sources such as the driving units  110 . Portions of the to-be-connected portions  122  of the photoconductors  42  of the process cartridges  30  and the non-driving units  132  each have a rotatable shape, for example, a columnar shape, and are rotatably attached to the corresponding process cartridge bodies  40 . 
     In the image forming apparatus body  12 , the connecting portions  112  to which the to-be-connected portions  122  of the photoconductors  42  are to be connected are formed on the distal side in the direction in which the process cartridges  30  are inserted into the image forming apparatus body  12 . The connecting portions  112  are formed in such a manner that the gear portions  123  of the to-be-connected portions  122  of the photoconductors  42  are fitted into the corresponding connecting portions  112  in the axial direction of the connecting portions  112 . In each of the connecting portions  112 , an internal gear portion  113  that has a cylindrical shape and has plural second grooves  114  formed in an inward radial direction with respect to the axial direction of the connecting portion  112  is formed, and the first protrusions  124  of the gear portion  123  of each of the to-be-connected portions  122  are to be fitted into the plural second grooves  114  of the corresponding connecting portion  112 . In addition, the connecting portions  112  are connected to the corresponding driving units  110 . Each of the connecting portions  112  rotates with rotation of the corresponding driving unit  110 , and each of the photoconductors  42  that include the to-be-connected portions  122  rotates with rotation of the corresponding connecting portion  112 . 
     The gear portions  123  of the to-be-connected portions  122  and the internal gear portions  113  of the connecting portions  112  are each sized to form gaps between the internal gear portions  113  and the corresponding gear portions  123  when the gear portions  123  and the corresponding internal gear portions  113  are connected to each other. These gaps include gaps that are required when the gear portions  123  of the to-be-connected portions  122  are fitted into the corresponding internal gear portions  113  of the connecting portions  112  and gaps  134  that are formed between, when the process cartridges  30  are mounted in the image forming apparatus body  12 , first peak portions  126  of the first protrusions  124  of the gear portions  123  of the to-be-connected portions  122  and second valley portions  116  of the second grooves  114  of the internal gear portions  113  of the corresponding connecting portions  112  into which the first peak portions  126  are to be fitted and between first valley portions  130  of first grooves  128  of the gear portions  123  of the to-be-connected portions  122  and second peak portions  120  of second protrusions  118  of the internal gear portions  113  of the corresponding connecting portions  112  into which the first valley portions  130  are to be fitted (see  FIG. 5A ). 
     The raising and lowering units  136  are attached to the process cartridges  30  on the side on which the non-driving units  132  are present, and each of the raising and lowering units  136  changes the position of the corresponding process cartridge  30  in order to allow the process cartridge  30  to be mounted on and removed from the image forming apparatus body  12 . Operating each of the raising and lowering units  136  causes the position of the corresponding process cartridge  30  to change between a mounting position  154  and a retreat position  156  (see  FIGS. 3A to 3C ). The process cartridge  30  is located at the mounting position  154  when the process cartridge  30  is in a state of being mounted in the image forming apparatus body  12  and is located at the retreat position  156  when the process cartridge  30  is mounted onto and removed from the image forming apparatus body  12 . 
     Note that, in the exemplary embodiment, the mounting position  154  is a position where one of the process cartridges  30  is located when the process cartridge  30  is in a state of being mounted in the image forming apparatus body  12  and when the photoconductor  42  of the process cartridge  30  and a belt-shaped member  52 , which is disposed in the image forming apparatus body  12  and onto which a developer image is transferred, are in contact with each other. The belt-shaped member  52  will hereinafter be referred to as to-be-transferred member  52 . On the other hand, the retreat position  156  is a position where one of the process cartridges  30  is located when the position of a portion of the process cartridge  30  on the side on which the non-driving unit  132  is present is changed to a different position, for example, a position lower than the mounting position  154 , while maintaining the connection between the to-be-connected portion  122  of the photoconductor  42  and the corresponding connecting portion  112  of the image forming apparatus  10  in order to remove the process cartridge  30  from the image forming apparatus body  12 . 
     Each of the raising and lowering units  136  is mounted on the bottom surface side of the non-driving unit  132  of the corresponding process cartridge  30  in such a manner as to be capable of performing a repetitive motion. Each of the raising and lowering units  136  includes an operation portion  140  that is to be operated by a user who applies a force to the operation portion  140  and a column portion  148  that is formed at one end of the operation portion  140  and disposed between the bottom surface side of the non-driving unit  132  of the corresponding process cartridge  30  and a corresponding one of the support portions  108  in such a manner as to support the process cartridge  30 . The column portion  148  includes, on the side on which the bottom surface of the corresponding process cartridge body  40  is present, a projecting portion  146  projecting from the bottom surface of the corresponding process cartridge body  40  and a connecting portion  142  that is arranged so as to be capable of performing a repetitive motion, and the projecting portion  146  and the connecting portion  142  are attached to the column portion  148  with a shaft portion  144  that is capable of performing a repetitive motion. 
     Each of the column portions  148  includes a column end portion  150  that is in contact with the corresponding support portion  108  of the image forming apparatus body  12 . The column end portion  150  is attached to, for example, a spring member  152  that is disposed in the column portion  148  and that has elasticity, so that a pressing force between the column end portion  150  and the corresponding process cartridge  30  and a pressing force that is applied to the photoconductor  42  of the process cartridge  30  against the to-be-transferred member  52  of the image forming apparatus body  12  are adjusted. 
     Thus, operating each of the raising and lowering units  136  causes the position of a portion of the corresponding process cartridge  30  on the side on which the non-driving unit  132  is present to change between the mounting position  154 , where the process cartridge  30  is located when the process cartridge  30  is in a state of being mounted in the image forming apparatus body  12 , and the retreat position  156 , to which the process cartridge  30  is retreated in order to be mounted onto and removed from the image forming apparatus body  12 . 
     The developing units  46  develop latent images, which are formed on the corresponding photoconductors  42 , with corresponding developers of Y, M, C, and K contained therein. 
     The optical writing device  32  is used as a latent-image-forming device and radiates light onto the photoconductors  42  in such a manner as to form latent images on surfaces of the photoconductors  42 . 
     The transfer device  34  includes the to-be-transferred member  52 , which is used as a transfer member, first transfer rollers  54 Y,  54 M,  54 C, and  54 K, each of which is used as a first transfer device, a second transfer roller  56 , which is used as a second transfer device, and a cleaning device  58 . 
     The to-be-transferred member  52  is in the form of, for example, an endless belt and is supported by five support rollers  60   a ,  60   b ,  60   c ,  60   d , and  60   e  in such a manner as to be rotatable in a direction indicated by an arrow in  FIG. 1 . At least one of the support rollers  60   a ,  60   b ,  60   c ,  60   d , and  60   e  is coupled to a power source (not illustrated) such as a motor and rotates as a result of receiving a driving force of the power source, so that the to-be-transferred member  52  is driven so as to rotate. Note that in the case where the process cartridges  30  are mounted in the image forming apparatus body  12 , the photoconductors  42  of the process cartridges  30  and the to-be-transferred member  52  are in contact with each other (see  FIG. 3A ). 
     The support roller  60   a  is disposed in such a manner as to face the second transfer roller  56  and functions as a backup roller of the second transfer roller  56 . A nip part defined by the second transfer roller  56  and the support roller  60   a  serves as a second transfer position. 
     Each of the first transfer rollers  54  transfers a corresponding one of developer images, which have been formed on the surfaces of the photoconductors  42  by the developing units  46 , onto the to-be-transferred member  52 . 
     The second transfer roller  56  transfers developer images of Y, M, C, and K, which have been transferred to the to-be-transferred member  52 , onto one of recording media. 
     The cleaning device  58  includes a scraper  62  that scrapes off the developers of the different colors remaining on a surface of the to-be-transferred member  52  after the developer images of the different colors have been transferred to the recording medium by the second transfer roller  56 . The developers that are scraped off by the scraper  62  are collected in a body of the cleaning device  58 . 
     The recording-media feeder  22  includes a recording-media container  72  in which recording media are accommodated in such a manner as to be stacked on top of one another, a transport roller  74  that extracts one of the recording media, which are accommodated in the recording-media container  72 , the recording medium to be extracted being at the top of the stacked recording media, and transports the extracted recording medium toward the image forming unit  20 , and a retard roller  76  that separates the recording media one by one and prevents the plural recording media from being transported to the image forming unit  20  while superposed with each other. 
     The transport path  24  is formed of a transport path  82  and a reverse transport path  84 . 
     The transport path  82  is a transport path along which one of the recording media fed from the recording-media feeder  22  is transported to the image forming unit  20  and along which the recording medium, on which an image has been formed, is ejected to the ejection part  14 . The transport roller  74 , the retard roller  76 , registration rollers  86 , the transfer device  34 , a fixing device  88 , and ejection rollers  90  are disposed along the transport path  82  in this order starting from an upstream side in the direction in which the recording media is to be transported. 
     The registration rollers  86  cause a leading end of one of the recording media transported by the recording-media feeder  22  to be temporarily stationary and then sends out the recording medium toward the transfer device  34  in accordance with the timing at which image formation is performed. 
     The fixing device  88  includes a heating roller  88   a  and a pressure roller  88   b  and fixes developer images onto one of the recording media that passes between the heating roller  88   a  and the pressure roller  88   b  by heating the recording medium and applying pressure to the recording medium. 
     The ejection rollers  90  eject the recording medium, to which the developer images have been fixed by the fixing device  88 , to the ejection part  14 . 
     The reverse transport path  84  is a transport path used for inverting the front and rear surfaces of a recording medium, the recording medium having developer images formed on one of the front and rear surfaces thereof, and for returning the recording medium toward the image forming unit  20 . For example, a pair of reverse-transport rollers  98   a  and a pair of reverse-transport rollers  98   b  are disposed along the reverse transport path  84 . 
     One of the recording media is transported to the position where the ejection rollers  90  are disposed along the transport path  82 , and the ejection rollers  90  rotate in a reverse direction in a state where a trailing end portion of the recording medium is nipped by the ejection rollers  90 , so that the recording medium is fed to the reverse transport path  84 . The recording medium, which has been fed to the reverse transport path  84 , is transported to a position upstream of the registration rollers  86  by the pairs of transport rollers  98   a  and  98   b.    
     Mounting and removing the process cartridges  30  onto and from the image forming apparatus body  12  will now be described. 
     First, the case of removing one of the process cartridges  30  from the image forming apparatus body  12  will be described. When the process cartridge  30  that has been mounted in the image forming apparatus  10  is removed, first, the opening and closing portion  104 , which is formed in a side surface of the image forming apparatus body  12 , is opened in such a manner as to expose the process cartridge  30  through the opening  102  (see  FIG. 2 ). 
     Next, as illustrated in  FIG. 3A  and  FIG. 3B , the raising and lowering unit  136 , which is attached to the process cartridge  30  and which forms part of the corresponding retreat mechanism  109 , is operated in such a manner as to change the position of the process cartridge  30  from the mounting position  154  to the retreat position  156 . This operation is performed by, first, lowering the operation portion  140  of the raising and lowering unit  136 , which faces upward, toward the side on which the opening  102  is present by applying a force to the operation portion  140  in such a manner as to cause the operation portion  140  to be horizontally placed. In this case, the operation portion  140  is rotated around the shaft portion  144 . 
     By moving the operation portion  140 , the column portion  148 , which is formed on the lower side of the connecting portion  142 , also rotates around the shaft portion  144 . As a result of the rotation of the column portion  148 , the column end portion  150  of the column portion  148  slides over the support portion  108  of the image forming apparatus body  12 , and the column portion  148  is moved to a position where the column portion  148  is in contact with the bottom surface of the process cartridge body  40 . 
     As a result of the column portion  148  moving as described above, the process cartridge  30  is in a state of not being supported by the column portion  148 , and a portion of the process cartridge  30  on the side on which the non-driving unit  132  is present moves downward. This downward movement of the process cartridge  30  stops when the bottom surface of the process cartridge  30  reaches the corresponding guiding portion  106 . In addition, the spring member  152 , which is disposed in the column portion  148 , expands by releasing its elastic energy. 
     As illustrated in  FIG. 4A  and  FIG. 4B , when the process cartridge  30  is moved to the retreat position  156 , although the portion of the process cartridge  30  on the side on which the non-driving unit  132  is present moves downward, the connection between the to-be-connected portion  122  and the connecting portion  112  is maintained. In this case, as illustrated in  FIG. 5A  and  FIG. 5B , the gear portion  123  of the to-be-connected portion  122  and the internal gear portion  113  of the corresponding connecting portion  112  are connected to each other with the gaps  134 , which are formed when the process cartridge  30  is mounted in the image forming apparatus body  12 , formed therebetween. Thus, when the process cartridge  30  is inclined, gaps  135 , which are required for the to-be-connected portion  122  to be inclined in the connecting portion  112  and which are formed when the process cartridge  30  is retreated, are formed between the first peak portions  126  of the first protrusions  124  of the gear portion  123  of the to-be-connected portion  122  and the second valley portions  116  of the second grooves  114  of the internal gear portion  113  of the connecting portion  112  into which the first peak portions  126  are to be fitted and between the first valley portions  130  of the first grooves  128  of the gear portion  123  of the to-be-connected portion  122  and the second peak portions  120  of the second protrusions  118  of the internal gear portion  113  of the connecting portion  112  into which the first valley portions  130  are to be fitted. 
     When the process cartridge  30  is obliquely disposed as a result of the portion of the process cartridge  30  on the side on which the non-driving unit  132  is present moving downward, the process cartridge  30  is located at the retreat position  156 , which is the position where the process cartridge  30  is to be located when the process cartridge  30  is mounted onto and removed from the image forming apparatus body  12 . As a result of the process cartridge  30  moving to the retreat position  156 , the photoconductor  42  of the process cartridge  30  and the to-be-transferred member  52  of the image forming apparatus body  12  are disconnected from each other. 
     After that, as illustrated in  FIG. 3C , the process cartridge  30  at the retreat position  156  is pulled out obliquely, so that the connecting portion  112  and the to-be-connected portion  122  are disconnected from each other (see  FIG. 4C ), and the process cartridge  30  is removed from the image forming apparatus body  12  through the process cartridges  30 . Note that, in this case, the process cartridge  30  is pulled out along the guiding portion  106  that is inclined in such a manner as to correspond to the retreat position  156  of the process cartridge  30 , so that the process cartridge  30  may be smoothly removed from the image forming apparatus body  12  through the process cartridges  30 . 
     The case where one of the process cartridges  30  is mounted onto the image forming apparatus body  12  will now be described. The mounting operation of the process cartridge  30  is started in the above-described state where the process cartridge  30  has been removed from the image forming apparatus body  12  through the opening  102 . 
     First, as illustrated in  FIG. 6A  and  FIG. 6B , the process cartridge  30  is inserted obliquely through the opening  102  of the image forming apparatus body  12  in such a manner as to be located at the retreat position  156 . This insertion operation is performed by using the guiding portion  106  that is obliquely disposed with respect to the opening  102 . Regarding the raising and lowering unit  136 , which is attached to the process cartridge  30 , the operation portion  140  and the column portion  148  are in a state of being horizontally placed, that is, the column portion  148  is in contact with the bottom surface of the process cartridge body  40 . 
     When the process cartridge  30  is inserted into the image forming apparatus body  12 , the connecting portion  112  of the image forming apparatus body  12  and the to-be-connected portion  122  of the photoconductor  42  of the process cartridge  30  are fitted to each other. The connecting portion  112  and the to-be-connected portion  122  are fitted to each other by inserting the to-be-connected portion  122  into the connecting portion  112  in an oblique direction (see  FIG. 4C ). In this case, as described above, gaps are formed between the gear portion  123  of the to-be-connected portion  122  and the internal gear portion  113  of the connecting portion  112  as illustrated in  FIG. 5A  and  FIG. 5B , the gaps including the gaps  135  that are formed, when the process cartridge  30  is retreated, between the first peak portions  126  of the first protrusions  124  of the gear portion  123  of the to-be-connected portion  122  and the second valley portions  116  of the second grooves  114  of the internal gear portion  113  of the connecting portion  112  into which the first peak portions  126  are to be fitted and between the first valley portions  130  of first grooves  128  of the gear portion  123  of the to-be-connected portion  122  and the second peak portions  120  of second protrusions  118  of the internal gear portion  113  of the connecting portions  112  into which the first valley portions  130  are to be fitted. 
     Next, as illustrated in  FIG. 6B  and  FIG. 6C , the raising and lowering unit  136  of the process cartridge  30 , which has been received by the image forming apparatus body  12 , is operated in such a manner as to change the position of the process cartridge  30  from the retreat position  156  to the mounting position  154 . In this operation, a force is applied to the operation portion  140  of the raising and lowering unit  136 , and the operation portion  140  is moved in a direction in which the position of the operation portion  140  is changed from a horizontally-placed position to a vertically-placed position. In this case, the operation portion  140  is rotated around the shaft portion  144 . 
     Upon the rotation the operation portion  140 , the column portion  148 , which is formed on the lower side of the connecting portion  142 , also rotates around the shaft portion  144 , and the position of the column portion  148  is changed from a horizontally-placed position to a vertically-placed position. As a result of the rotation of the column portion  148 , the column end portion  150  slides over the support portion  108  of the image forming apparatus body  12 , and the position of the column portion  148  is changed to the vertically-placed position, so that the process cartridge  30  is moved upward. 
     As a result of the column portion  148  being moved to a predetermined position, the process cartridge  30  is located at the mounting position  154  and mounted in the image forming apparatus body  12 . In this case, the process cartridge  30  is mounted in the image forming apparatus body  12 , so that the photoconductor  42  of the process cartridge  30  and the to-be-transferred member  52  of the image forming apparatus body  12  are in contact with each other. In addition, the gaps formed between the connecting portion  112  and the to-be-connected portion  122  changes from the gaps  135  when the process cartridge  30  is retreated to the gaps  134  when the process cartridge  30  is mounted in the image forming apparatus body  12  (see  FIG. 4A ,  FIG. 4B ,  FIG. 5A , and  FIG. 5B ). 
     Along the movement of the column end portion  150  of the column portion  148 , the spring member  152 , which is disposed in the column portion  148 , contracts and moves so as to apply pressure between the column end portion  150  and the process cartridge  30 , so that the pressing force between the photoconductor  42  of the process cartridge  30  and the to-be-transferred member  52  are adjusted. After that, the opening and closing portion  104  is closed, and the mounting of the process cartridge  30  is finished. 
     The foregoing description of the exemplary embodiment of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in the art. The embodiment was chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to understand the invention for various embodiments and with the various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents.