Patent Publication Number: US-11042106-B2

Title: Image forming apparatus having removable transfer unit

Description:
TECHNICAL FIELD 
     The present invention relates to an image forming apparatus, such as a copying machine, a printer, a facsimile machine or a multi-function machine having a plurality of functions of these machines. 
     BACKGROUND ART 
     As an image forming apparatus, a constitution in which a toner image is transferred from a photosensitive drum as an image bearing member onto an intermediary transfer belt as a transfer member has been known. Further, when a transfer unit including such an intermediary transfer belt is subjected to maintenance, a constitution in which the transfer unit is pulled out together with a gear unit from an apparatus main assembly and is inclined relative to the supporting unit has been proposed (Japanese Laid-Open Application (JP-A) 2005-309036). 
     Here, as the image forming apparatus, a constitution in which the toner image is formed using a liquid developer containing toner and a carrier liquid has been conventionally known. In the case where in such a constitution using the liquid developer, the transfer unit is inclined during maintenance as in JP-A 2005-309036, there is a possibility that the liquid developer deposited on a part of the transfer unit flows along an inclination direction and leaks to an unintended portion. 
     That is, in the case of JP-A 2005-309036, a constitution using powdery toner is employed, and therefore, a possibility of toner leakage is low even when the transfer unit is inclined. On the other hand, in the case of a constitution using the liquid developer, the liquid developer is liable to flow along a wall surface compared with the powder. Further, even when the constitution in which the transfer unit is inclined is not employed, there is a liability that the liquid developer leaks to an outside by flowing along a shaft portion of a roller member stretching the belt through the intermediary transfer belt and has an influence on a peripheral member. For example, there is a liability that the liquid developer enters a bearing portion of the roller and increases a driving torque and that the liquid developer enters an electric contact portion or the like of the roller and electrical connection becomes unstable. 
     SUMMARY OF THE INVENTION 
     Problem to be Solved by the Invention 
     The present invention aims at providing an image forming apparatus, in which image formation is carried out using a liquid developer transferred on an intermediary transfer belt, capable of suppressing leakage of the liquid developer along a shaft portion of a rotatable member contacting a transfer belt. 
     Means for Solving the Problem 
     According to an aspect of the present invention, there is provided an image forming apparatus comprising:
         an image bearing member for bearing an image formed with a developer containing toner and a carrier;   an endless intermediary transfer belt onto which the image is transferred from the image bearing member;   a transfer roller for transferring the image onto the intermediary transfer belt, wherein the transfer roller includes a roller portion contacting an inner peripheral surface of the intermediary transfer belt and a shaft portion having a diameter smaller than a diameter of the roller portion on an outside of the roller portion;   a bearing portion for rotatably supporting the shaft portion; and   a flange portion provided between the roller portion and the bearing portion with respect to an axial direction of the transfer roller.       

     According to another aspect of the present invention, there is provided an image forming apparatus comprising:
         an image bearing member for bearing an image formed with a developer containing toner and a carrier;   an endless intermediary transfer belt onto which the image is transferred from the image bearing member;   a transfer roller for transferring the image onto the intermediary transfer belt, wherein the transfer roller includes a roller portion contacting an inner peripheral surface of the intermediary transfer belt and a shaft portion having a diameter smaller than a diameter of the roller portion on an outside of the roller portion;   a bearing portion for rotatably supporting the shaft portion;   an electrical contact portion, contacting the shaft portion at a contact portion, for supplying a bias to the shaft portion; and   a flange portion positioned between the roller portion and the electrical contact portion with respect to an axial direction of the transfer roller.       

     According to a further aspect of the present invention, there is provided an image forming apparatus comprising:
         an image bearing member for bearing an image formed with a developer containing toner and a carrier;   an endless intermediary transfer belt onto which the image is transferred from the image bearing member;   a cleaning roller for cleaning the intermediary transfer belt in contact with an inner surface or an outer surface of the intermediary transfer belt, wherein the cleaning roller includes a roller portion contacting the intermediary transfer belt and a shaft portion having a diameter smaller than a diameter of the roller portion on an outside of the roller portion;   a bearing portion for rotatably supporting the shaft portion;   an electrical contact portion, contacting the shaft portion at a contact portion for supplying a bias to the shaft portion or for grounding the shaft portion; and   a flange portion provided between the roller portion and the bearing portion with respect to an axial direction of the transfer roller.       

    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic structural view of an image forming apparatus according to a first embodiment. 
         FIG. 2  is a schematic structural view of an image forming portion according to the first embodiment. 
         FIG. 3  includes schematic structural perspective views of a supporting unit according to the first embodiment, in which part (a) shows a pulled-out state, and part (b) shows an inclined state. 
       In  FIG. 4 , part (a) is a schematic structural side view of a transfer unit according to the first embodiment, part (b) is a sectional view of a portion for supporting the transfer unit according to the first embodiment relative to the supporting unit, and part (c) is sectional view of a portion for rotating and holding the transfer unit according to the first embodiment. 
         FIG. 5  is a sectional view showing a schematic structure of a transfer cleaning portion according to the first embodiment on an end portion side. 
         FIG. 6  is a sectional view showing a schematic structure of a transfer cleaning portion on an end portion side during a horizontal state of a transfer unit according to a second embodiment. 
         FIG. 7  is a sectional view showing a schematic structure of the transfer cleaning portion on the end portion side during inclination of the transfer unit according to the second embodiment. 
         FIG. 8  is a side view showing a schematic structure of a primary transfer portion on an end portion side in a comparison example in a state in which an intermediary transfer belt is cut. 
         FIG. 9  is a perspective view showing a schematic structure of a primary transfer portion according to a third embodiment in a state in which a part of an intermediary transfer belt is cut. 
         FIG. 10  is a side view showing a schematic structure of the primary transfer portion according to the third embodiment on an end portion side in a state in which the intermediary transfer belt is cut. 
         FIG. 11  includes side views each showing a schematic structure of a primary transfer portion according to a fourth embodiment on an end portion side in a state in which an intermediary transfer belt is cut, in which part (a) shows the primary transfer portion according to a first example, and part (b) shows the primary transfer portion according to a second example. 
         FIG. 12  includes side views each showing a schematic structure of a primary transfer portion according to a fifth embodiment on an end portion side in a state in which an intermediary transfer belt is cut, in which part (a) shows the primary transfer portion according to a first example, and part (b) shows the primary transfer portion according to a second example. 
         FIG. 13  includes side views each showing a schematic structure of a primary transfer portion according to a sixth embodiment on an end portion side in a state in which an intermediary transfer belt is cut, in which part (a) shows the primary transfer portion according to a first example, and part (b) shows the primary transfer portion according to a second example. 
         FIG. 14  is a side view showing a schematic structure of the primary transfer portion according to a seventh embodiment on an end portion side in a state in which the intermediary transfer belt is cut. 
     
    
    
     EMBODIMENTS FOR CARRYING OUT THE INVENTION 
     First Embodiment 
     A first embodiment will be described using  FIG. 1  to  FIG. 5 . First, a schematic structure of an image forming apparatus of this embodiment will be described using  FIG. 1 . 
     [Image Forming Apparatus] 
     As shown in  FIG. 1 , an image forming apparatus  100  is a full-color printer of an electrophotographic type in which four image forming portions  1 Y,  1 M,  1 C and  1 K are provided correspondingly to four colors of yellow (Y), magenta (M), cyan (C) and black (K). In this embodiment, the image forming apparatus  100  is of a tandem type in which the image forming portions  1 Y,  1 M,  1 C and  1 K are provided along a rotational direction of an intermediary transfer belt  10  (described later). The image forming apparatus  100  forms a toner image on a recording material depending on an image signal from an external device, such as a personal computer, communicatably connected with an image forming apparatus main assembly, for example. As the recording material, a sheet material such as a sheet, a plastic film, a cloth or the like is cited. 
     The image forming apparatus  100  includes an image forming unit  101 , a transfer unit  102 , a transfer cleaning portion  103 , a supporting unit  104  (see parts (a) and (b) of  FIG. 3 ), a recording material feeding portion  105 , and a casing (see parts (a) and (b) of  FIG. 3 ) capable of accommodating these members. The image forming apparatus  100  receives information (image signal) on image data from an external terminal (not shown). The received image data is processed by a CPU of a controller  120  for carrying out control of entirety of the image forming apparatus  100 . Then, in the image forming portions  1 Y,  1 M,  1 C and  1 K for the respective colors of the image forming unit  101 , toner images of the respective colors are formed. 
     Incidentally, the four image forming portions  1 Y,  1 M,  1 C and  1 K have the substantially same constitution except that development colors are different from each other. Accordingly, in the following, the image forming portion  1 Y will be described as a representative, and other image forming portions will be omitted from description. 
     The image forming portion  1 Y includes a cylindrical photosensitive member as an image bearing member capable of bearing the toner image, i.e., includes a photosensitive drum  3 . At a periphery of the photosensitive drum  3 , along a rotational direction a thereof, a charging device  4  for electrically charging the photosensitive drum  3 , an exposure device (laser scanner)  2   a  for forming an electrostatic latent image on the charged photosensitive drum  3 , a developing device  5 , a drum cleaning member  13  and the like are provided. 
     When an image is formed, the photosensitive drum  3  is charged by the charging device  4  and is irradiated at a non-image portion with laser output light  2   b  based on the image information by the exposure device  2   a , so that the electrostatic latent image is formed on the photosensitive drum  3 . To the electrostatic latent image formed on the photosensitive drum  3 , a liquid developer containing toner and a carrier liquid is supplied by a developing roller  6  rotating in a rotational direction b while being held (supported) by a container of the developing device  5 . By this, the electrostatic latent image on the photosensitive drum  3  is developed by the toner, so that the toner image is formed on the photosensitive drum  3 . 
     The liquid developer is a mixed liquid in which the toner is mixed in the carrier liquid. The liquid developer containing the toner and the carrier liquid is supplied from a developer bottle  7  into the container of the developing device  5  through a developer feeding path  9  by a developer supply pump  8 . 
     The toner image formed on the photosensitive drum  3  is primary-transferred onto the intermediary transfer belt  10  as a transfer member of the transfer unit  102 . The intermediary transfer belt  10  is an endless belt and is stretched by stretching rollers  10   a  and  10   b  and a secondary transfer inner roller  12   a  which are a plurality of stretching rollers. Further, between the stretching rollers  10   a  and  10   b , a primary transfer roller  11  is provided so as to sandwich the intermediary transfer belt  10  between itself and the photosensitive drum  3 . The primary transfer roller  11  is urged toward the photosensitive drum  3  by a spring as an unshown urging means. Further, a primary transfer portion T 1  is formed between the photosensitive drum  3  and the primary transfer roller  11 . 
     The intermediary transfer belt  10  is rotationally driven in an arrow c direction by the stretching roller  10   a  which is also a driving roller. By applying a voltage (primary transfer bias) to each of the primary transfer rollers  11 , at the respective primary transfer portions T 1 , the toner images on the photosensitive drums  3  are successively transferred superposedly, so that a full-color toner image is formed on the intermediary transfer belt  10  (on the transfer member). At this time, the liquid developer is also supplied from the photosensitive drums to the intermediary transfer belt  10 . Accordingly, on the intermediary transfer belt  10 , the liquid developer is to be transferred. 
     On an outer peripheral surface of the intermediary transfer belt  10  stretched by the secondary transfer inner roller  12   a , a secondary transfer outer roller  12   b  is provided so as to contact the intermediary transfer belt  10 . Further, between the secondary transfer inner surface  12   a  and the secondary transfer outer roller  12   b , a secondary transfer portion T 2  is formed. The toner images on the intermediary transfer belt  10  are transferred, at the secondary transfer portion T 2 , onto a recording material fed by a recording material feeding portion  105  described later) under application of a voltage (secondary transfer bias) to the secondary transfer outer roller  12   b . Incidentally, the secondary transfer bias may also be applied to the secondary transfer inner roller  12   a  by changing a polarity thereof from a polarity of the secondary transfer outer roller  12   b.    
     The liquid developer remaining on the photosensitive drum  3  after the transfer thereof onto the intermediary transfer belt  10  is removed by a drum cleaning member  13  and is collected in a drum cleaning container  14 . Further, the liquid developer remaining on the intermediary transfer belt  10  after the transfer thereof onto the recording material is removed by a transfer cleaning portion  103 . A detailed structure of the transfer cleaning portion  103  will be described later. 
     Next, the recording material feeding portion  105  will be described. The recording materials are stacked on a feeding deck  17 . A size of the stacked recording materials is detected by an unshown size detecting portion or by setting by a user and a serviceman and the like. When the recording materials are fed, an uppermost portion recording material stacked on the feeding deck  17  is picked up by a pick-up roller  18  and is separated in a single sheet by a separation roller pair  19  provided downstream of the pick-up roller  18 . Then, the recording material fed from the feeding deck  17  is fed to a feeding path  20 . 
     The recording material fed to the feeding path  20  is fed to a registration roller pair  22  by a feeding roller pair  21 . The registration roller pair  22  temporarily stops rotation thereof, and the recording material is abutted against the registration roller pair  22 , so that deviation of the recording material in a (recording material) feeding direction is corrected. Then, the registration roller pair  22  feeds the recording material to the secondary transfer portion T 2  in synchronism with timing of the toner images (images) formed on the liquid developer held by the intermediary transfer belt  10 . By this, deviation of the toner images to be transferred on the recording material is corrected to an appropriate position. The toner images transferred on the recording material at the secondary transfer portion are fixed on the recording material in a fixing unit (not shown). 
     [Transfer Cleaning Portion] 
     Next, a structure of the transfer cleaning portion  103  will be described using  FIG. 2 . The transfer cleaning portion  103  includes a cleaning roller  15  as a cleaning member (cleaning roller), a cleaning blade  24  and a cleaning container  16  as a collecting portion. At a position opposing the cleaning roller  15  while sandwiching the intermediary transfer belt  10  with the cleaning roller  15 , an opposing roller  23  is provided so as to sandwich the intermediary transfer belt  10  between itself and the cleaning roller  15 . 
     The cleaning roller  15  is rotationally driven by an unshown motor in an arrow d direction along the rotational direction c of the intermediary transfer belt  10  while contacting the outer peripheral surface of the intermediary transfer belt  10  on which the liquid developer deposits. To the cleaning roller  15 , a voltage (cleaning bias) is applied from a voltage source  15 A. The opposing roller  23  is connected to the ground. 
     The toner remaining on the intermediary transfer belt  10  is charged by negative electric charges, and therefore, a positive voltage opposite in polarity to the charge polarity of the toner is applied from the voltage source  15 A to the cleaning roller  15 . To the cleaning roller  15 , the bias is applied from the voltage source  15 A through an electric contact portion contacting a shaft portion  29   b  of the cleaning roller  15 . The opposing roller  23  is connected to the ground, and therefore, such a voltage is applied to the cleaning roller  15 , so that the toner remaining on the intermediary transfer belt  10  is electrophoretically moved to the cleaning roller  15 . 
     At this time, in order to bring the cleaning roller  15  into contact with the intermediary transfer belt  10  reliably, by urging the opposing roller  23  in an arrow e direction by a spring  23 A as an urging member, the intermediary transfer belt  10  is pressed against the cleaning roller  15 . Thus, the cleaning roller  15  is contacted to the intermediary transfer belt  10  and the voltage is applied to the cleaning roller  15 , and thus the toner is electrophoretically moved, so that the liquid developer containing the toner remaining on the intermediary transfer belt  10  can be removed by the cleaning roller  15 . 
     The cleaning blade  24  is disposed so as to be contacted to the cleaning roller  15  with an acute angle with respect to the rotational direction d of the cleaning roller  15 . That is, an angle formed between a portion, with respect to the rotational direction d, downstream of a contact point of a tangential line of an outer peripheral surface of the cleaning roller  15  passing through the contact point where the cleaning roller  15  and the cleaning blade  24  contact each other, and the cleaning blade  24  is set at the acute angle. In an illustrated example, the cleaning roller  15  is rotated in the counterclockwise direction, and the cleaning blade  24  is contacted to the cleaning roller  15  on a side upstream of a lowest point of the cleaning roller  15  with respect to the rotational direction d. For this reason, the cleaning blade  24  is positioned so that a contact position is in an upper end portion thereof with respect to a vertical direction, and is disposed so as to be inclined with respect to the vertical direction. 
     As described above, the liquid developer containing residual toner electrophoretically moved from the intermediary transfer belt  10  to the cleaning roller  15  is removed by the cleaning blade  24  and is moved along the surface of the cleaning blade  24  in a direction of gravitation. 
     The cleaning container  16  accommodates the cleaning roller  15  and the cleaning blade  24  and includes a bottom plate portion  25  below the cleaning roller  15  and the cleaning blade  24 . Accordingly, the liquid developer removed by the cleaning blade  24  drops from the cleaning blade  24  onto the bottom plate portion  25  of the cleaning container  16 . Further, the bottom plate portion  25  is formed so as to be capable of collecting also the liquid developer directly dropped from the cleaning roller  15 . 
     The bottom plate portion  25  forms a collection path for permitting collection of the dropped liquid developer and is formed so that the liquid developer is collected at a discharge opening  26  formed in the cleaning container  16 . In this embodiment, the discharge opening  26  is formed at a substantially center portion of the cleaning container  16  and in a lower end position of a side plate portion on one end side with respect to an axial direction of the cleaning roller  15  in a cross-section perpendicular to the axial direction of the cleaning roller  15 . 
     Accordingly, the bottom plate portion  25  is provided with a slope from an end portion of the bottom plate portion  25  to the substantially center portion so that the substantially center portion in the above-described cross-section is lowest and is provided with the slope so that one end side, with respect to the axial direction of the cleaning roller  15 , where the discharge opening  26  is formed is lowest. Further, the liquid developer dropped on the bottom plate portion  25  is discharged through the discharge opening  26 . The discharge opening  26  is connected to an unshown developer collecting container, and the liquid developer discharged through the discharge opening  26  is stored in the developer collecting container. 
     Incidentally, in this embodiment, the discharge opening  26  is provided on a rear (surface) side of the image forming apparatus  100 . Here, a front (surface) side of the image forming apparatus  100  is a side where a user or the like person operates the image forming apparatus  100 , and for example, a side where an operating portion such as an operating panel is provided. Further, the rear side is a side opposite from this front side and is the above-described one end side with respect to the axial direction of the cleaning roller  15 . 
     [Supporting Voltage] 
     Next, as regards the supporting unit  104 , description will be made using parts (a) and (b) of  FIG. 3  and parts (a) to (c) of  FIG. 4 . The supporting unit  104  as a holding member is capable of holding the transfer unit  102  at a first position where the liquid developer is capable of being transferred from the photosensitive drum  3  onto the intermediary transfer belt  10  as described above. At the first position, axial directions of the rollers of the transfer unit  102 , such as the stretching rollers  10   a  and  10   b , the secondary transfer inner roller  12   a , the respective primary transfer rollers  11  and the like are substantially horizontal to a horizontal direction. 
     The transfer unit  102  includes, as described above, the intermediary transfer belt  10  stretched by the stretching rollers  10   a  and  10   b  and the secondary transfer inner roller  12   a . Further, the transfer unit  102  includes a pair of supporting frames  200   a  and  200   b  provided on both sides with respect to a widthwise direction crossing the rotational direction of the intermediary transfer belt  10 . In this embodiment, the widthwise direction is the same direction as the axial directions of the stretching rollers  10   a  and  10   b  and the secondary transfer inner roller  12   a . Both end portions of the stretching rollers  10   a  and  10   b , the secondary transfer inner roller  12   a  and the respective primary transfer rollers  11  are supported rotatably by the pair of supporting frames  200   a  and  200   b.    
     Such a transfer unit  102  is configured so that the transfer unit  102  cannot be pulled out from a casing  110  of the image forming apparatus  100 , in order to perform a maintenance operation such as an exchange of the intermediary transfer belt  10 . Further, the transfer unit  102  is held by the supporting unit  104  so as to be capable of being inclined in an arrow f direction of part (b) of  FIG. 3  in a state of being pulled out from the casing  110 . Further, the supporting unit  104  is capable of being pulled out toward the front side of the image forming apparatus  100  relative to the casing  110  and is capable of being inclined into the casing  110 . For this reason, the supporting unit  104  is held by a slide rail  27  provided in the casing  110  and is capable of being inclined and pulled out along the slide rail  27 . 
     The supporting unit  104  includes a front side supporting portion  210   a  on the front side (downstream side with respect to a pulling-out direction) of the image forming apparatus  100  and includes a rear side supporting portion  210   b  on the rear side (upstream side with respect to the pulling-out direction) of the image forming apparatus  100 . The front side supporting portion  210   a  and the rear side supporting portion  210   b  are connected by connecting portions  211  at opposite end portions with respect to a direction crossing the pulling-out direction. The transfer unit  102  is disposed in a space enclosed by such front side supporting portion  210   a , rear side supporting portion  210   b  and pair of connecting portions  211 . 
     During maintenance of the transfer unit  102 , the supporting unit  104  holding the transfer unit  102  is pulled out of the casing  110  as shown in part (a) of  FIG. 3 . Then, as shown in part (b) of  FIG. 3 , the transfer unit  102  is inclined relative to the supporting unit  104  in an arrow f direction from a first position to a second position. That is, the transfer unit  102  is, as shown in part (a) of  FIG. 3 , supported relative to the supporting unit  104  by hinges  28  rotatably about one end side (rear side, upstream side with respect to the pulling-out direction), as a center, with respect to the widthwise direction of the intermediary transfer belt  10 . Then, as shown in part (b) of  FIG. 3 , the other side (front side, downstream side with respect to the pulling-out direction) with respect to the widthwise direction of the intermediary transfer belt  10  is capable of being inclined to the second position where the other side is exposed to above the front side supporting portion  210   a  of the supporting unit  104 . 
     In a state in which the transfer unit  102  is inclined to the second position, for example, by loosening tension applied to the intermediary transfer belt  10 , it is possible to pull out the intermediary transfer belt  10  from the other side with respect to the widthwise direction. For this reason, a maintenance operation such as an exchange operation of the intermediary transfer belt  10  can be easily performed. For example, in the case where in a constitution in which the transfer unit  102  is held in the supporting unit  104  as in this embodiment, exchange or the like of the intermediary transfer belt  10  is carried out in the case where a constitution of inclining the transfer unit  102  is not employed, first, an operation of dismounting the front side supporting portion  210   a  or the like operation is needed. Then, after the intermediary transfer belt  10  is exchanged, an operation of assembling the front side supporting portion  210   a  is needed. On the other hand, as described above, when the transfer unit  102  is inclined, an operation such as the exchange of the intermediary transfer belt  10  can be performed without carrying out such dismounting and assembling operations of the front side supporting portion  210   a , so that the maintenance operation can be easily performed. 
     In this embodiment, in order to cause the transfer unit  102  to be capable of being inclined as described above, damper-incorporated hinges  28  are provided between the supporting frame  200   b  on one end side with respect to the widthwise direction of the intermediary transfer belt  10  and the rear side supporting portion  210   b  of the supporting unit  104 . Further, the transfer unit  102  includes projections  201  provided on the pair of supporting frames  200   a  and  200   b  so as to project in the widthwise direction. In part (a) of  FIG. 4 , a view of the front side supporting portion  200   a  as seen from the front side is shown. The projections  201  are provided at two positions spaced from each other at the same height position on a side surface the supporting frame  200   a  on the front side. The projections of the rear side supporting frame  200   b  are also similar to those of the front side supporting frame  200   a.    
     On the other hand, the supporting unit  104  includes, as shown in part (b) of  FIG. 4 , mounting portions  214  capable of mounting the projections  201  thereon at positions in alignment with the above-described projections  201  of the front side supporting portion  210   a  and the rear side supporting portion  210   b . Further, by mounting the respective projections  201  of the supporting frames  200   a  and  200   b  on the mounting portions  214 , respectively, the transfer unit  102  is supported at the first position by the supporting unit  104 . 
     Further, by mounting the respective projections  201  of the supporting frames  200   a  and  200   b  on the mounting portions  214 , respectively, so that the transfer unit  102  is supported at the first position by the supporting unit  104 . 
     Further, as shown in part (c) of  FIG. 4 , to the rear side supporting frame  200   b  of the transfer unit  102 , the hinges  28  supported rotatably in the arrow f direction about a rotation shaft  28   a  relative to the rear side supporting portion  210   b  are fixed. In the hinges  28 , dampers are incorporated and are configured to attenuate a moving speed of the transfer unit  102  when the transfer unit  102  moves from the inclined state in a direction toward the first position by gravitation. 
     Further, by the supporting frame  200   b , a lock arm  220  is supported rotatably about a rotation shaft  220   a  so as to project toward the rear side. The lock arm  220  rotates with the operation in which the transfer unit  102  is inclined and runs up onto an inclined surface of a stopper  212  provided on the supporting unit  104 , and holds the transfer unit  102  at the second position. In this embodiment, a rotation holding portion  230  capable of holding the transfer unit  102  at the second position is constituted by such hinges  28 , lock arm  220  and stopper  212 . Incidentally, a constitution in which the transfer unit  102  is inclined and held at an inclined position as described above is similar to the above-described first embodiment. 
     [Transfer Cleaning Portion Supporting Structure] 
     Next, a supporting structure for the transfer cleaning portion  103  will be described using  FIG. 5 . In the case of this embodiment, the transfer cleaning portion  103  is supported by the supporting unit  104  irrespective of the rotation of the transfer unit  102  as described above. That is, the cleaning container  16  is supported by the supporting unit  104 , and the cleaning roller  15  is rotatably supported, at opposite end portions with respect to the axial direction, by supporting wall portions  213  fixed to the supporting unit  104  via bearings  30  as holding side supporting portions. The cleaning blade  24  (see  FIG. 2 ) is also supported by the supporting unit  104 . 
     The cleaning roller  15  includes a roller portion  29   a  as a contact portion and shaft portions  29   b  provided at opposite end portions of the roller portion  29   a  with respect to the axial direction. The roller portion  29   a  contacts the intermediary transfer belt  10 . The shaft portions  29   b  are rotatably supported by the rollers  30 . In this embodiment, the cleaning roller  15  includes flanges  31  as restricting portions, each between the roller portion  29   a  and the bearing  30  on associated one of the opposite sides with respect to the axial direction, for restricting that the liquid developer reaches the bearing  30  from the roller portion  29   a.    
     The flange  31  is provided on the shaft portion  29   b , further on a roller portion  29   a  side than the bearing  30  is, so as to project from an outer peripheral surface of the shaft portion  29   b  in a radial direction. The flange  31  may also be provided integrally with the shaft portion  29   b , and separately, may also be provided by fixing a flange member to the shaft portion  29   b  by press fitting or the like. In either case, the flange  31  restricts that the liquid developer flows along the shaft portion  29   b  from the roller portion  29   a  and reaches the bearing  30 . 
     As described above, the transfer unit  102  is inclined relative to the supporting unit  104 . Here, the liquid developer deposits on the intermediary transfer belt  10  of the transfer unit  102  and on the cleaning roller  15  and the cleaning blade  24  of the transfer cleaning portion  103 . Further, in the cleaning container  16 , the case where the collected liquid developer accumulates also exists. Accordingly, in the case where the transfer cleaning portion  103  is supported by the supporting unit  104  so as to be inclined together with the supporting unit  104 , during inclination, for example, there is a liability that the liquid developer leaks out of the cleaning container  16 . Further, there is a liability that the liquid developer deposited on the cleaning roller  15  and the cleaning blade  24  flows along surfaces of these members and drop onto portions other than the cleaning container  16  during the inclination. 
     On the other hand, in this embodiment, the transfer cleaning portion  103  is supported by and fixed to the supporting unit  104  irrespective of the rotation of the transfer unit  102 . For this reason, even when the transfer unit  102  is inclined relative to the supporting unit  104  as described above during the maintenance, the transfer cleaning portion  103  is not inclined. For this reason, in order to prevent the leakage of the liquid developer from the transfer cleaning portion  103  during the inclination of the transfer unit  102 , even when a constitution such that the leakage is prevented is not prevented separately, it is possible to suppress the leakage of the liquid developer out of the cleaning container  16  or the like. 
     Further, the cleaning roller  15  and the cleaning blade  24  are supported by the supporting unit  104  even when the transfer unit  102  is inclined. For this reason, similarly as when the transfer unit  102  is not inclined, the liquid developer deposited on the cleaning roller  15  and the cleaning blade  24  drops into the transfer cleaning portion  103 . Accordingly, during the inclination of the transfer unit  102 , it is possible to suppress the drop of the liquid developer from the cleaning roller  15  or the like onto a portion other than the cleaning container  16 . 
     Description will be specifically made using  FIG. 5 . During image formation, the liquid developer is collected from the intermediary transfer belt  10  by the cleaning roller  15  and is deposited on the surface of the cleaning roller  15 . The liquid developer deposited on the surface of the cleaning roller  15  is scraped off by the cleaning blade  24  and is collected in the cleaning container  16  as shown by an arrow g of  FIG. 5 . 
     Further, in the case where the transfer unit  102  is inclined relative to the supporting unit  104 , the transfer cleaning portion  103  is not inclined together with the transfer unit  102 , but is supported by the supporting unit  104 . Accordingly, attitudes of the cleaning roller  15  and the cleaning container  16  are unchanged from those during the image formation. For this reason, as shown by the arrow g of  FIG. 5 , the liquid developer deposited on the surface of the cleaning roller  15  drops into the cleaning container  16  by gravitation. 
     Here, even when the transfer cleaning portion  103  is not inclined, a part of the liquid developer deposited on the surface of the cleaning roller  15  flows in the axial direction of the roller along the surface of the roller in some cases. Thus, the liquid developer flowing in the axial direction moves from the roller portion  29   a  toward the bearing  30  along the shaft portion  29   b . If the liquid developer enters the bearing  30 , the liquid developer contains the toner and has viscosity, so that there is a possibility that rotation accuracy of the bearing  30  lowers and a driving load increases. Further, there is also a possibility that the liquid developer passes through the bearing  30  and leaks to an outside of the cleaning container  16 . 
     On the other hand, in the case of this embodiment, on the shaft portion  29   b  between the roller portion  29   a  and the bearing  30 , the flange  31  with no through hole is provided. For this reason, the liquid developer flowing in the axial direction as described above is blocked by the flange  31  as shown by an arrow h and drops into the cleaning container  16  by gravitation, so that it is possible to suppress that the liquid developer reaches the bearing  30 . 
     The liquid developer dropped in the cleaning container  16  as shown by the arrows g and h flows toward the discharge opening  26  along the surface of the bottom plate portion  25 . Then, the liquid developer discharged through the discharge opening  26  is stored in an unshown developer collecting container. 
     Thus, in the case of this embodiment, the transfer cleaning portion  103  is supported by the supporting unit  104 . For this reason, the transfer unit  102  can be inclined without inclining the transfer cleaning portion  103 . For this reason, it is possible to suppress the leakage of the liquid developer capable of occurring by the inclination of the cleaning roller  15 . Further, the flange  31  is provided between the roller portion  29   a  and the bearing  30  of the cleaning roller  15 , and therefore, it is possible to suppress that the liquid developer flowing along the surface of the cleaning roller  15  in the axial direction reaches the bearing  30 . 
     Second Embodiment 
     A second embodiment will be described using  FIG. 6  and  FIG. 7 . In the above-described first embodiment, the constitution in which entirety of the transfer cleaning portion  103  is supported by the supporting unit  104  was described. On the other hand, in this embodiment, a cleaning container  16  of a transfer cleaning portion  103 A is supported by a supporting unit  104 A. Other constitutions and actions are similar to those in the above-described first embodiment, and therefore, as regards a redundant portion, the drawing and description will be omitted or briefly made, and the same reference numerals or symbols are added to the same constituent elements, and in the following, a portion different from the first embodiment will be principally described. 
     In this embodiment, the cleaning container  16  is supported by the supporting unit  104 A, but the cleaning roller  15  and the cleaning blade  24  (see  FIG. 2 ) are supported by a transfer unit  102 A. Accordingly, the cleaning roller  15  and the cleaning blade  24  rotate together with the transfer unit  102 A during maintenance. 
     For this reason, the cleaning roller  15  is rotatably supported, at opposite end portions with respect to the axial direction, by supporting wall portions  221  fixed to a pair of supporting frames  200   a  (see part (a) of  FIG. 4 ) and  200   b , respectively, of the transfer unit  102 A, via bearings  30   a  as unit side supporting portions. The cleaning blade  24  (see  FIG. 2 ) is also supported by the transfer unit  102 . Further, the cleaning roller  15  includes flanges  31   a  as restricting portions, each between the roller portion  29   a  and the bearing  30   a  on associated one of the opposite sides with respect to the axial direction, for restricting that the liquid developer reaches the bearing  30  from the roller portion  29   a.    
     Thus, by supporting the cleaning roller  15  on the transfer unit  102 A side, a deviation of alignment between the cleaning roller  15  and the intermediary transfer belt  10  is made small. Further, the cleaning roller  15  decreases an influence on a feeding property of the intermediary transfer belt  10 . That is, the stretching rollers  10   a  and  10   b  and the secondary transfer inner roller  12   a  are supported by the pair of supporting frames  200   a  and  200   b . Further, the cleaning roller  15  is supported via the bearings  30   a  by the supporting wall portions  221  fixed to the supporting frames  200   a  and  200   b . For this reason, each of the stretching rollers  10   a  and  10   b , the secondary transfer inner roller  12   a  and the cleaning roller  15  is supported by the supporting frames  200   a  and  200   b , so that a deviation of alignment among the respective rollers can be made small. 
     In the case of this embodiment, the liquid developer is collected from the transfer cleaning portion  103 A at a first position (during horizontality) and a second position (during inclination), respectively, in the following manner. First, in the case where the transfer unit  102 A shown in  FIG. 6  is in horizontality, the liquid developer which is collected from the intermediary transfer belt  10  and which is deposited on the surface of the cleaning roller  15  is scraped off by the cleaning blade  24  and is collected in the cleaning container  16  as shown by an arrow i of  FIG. 6 . Further, the liquid developer flowing along the surface of the cleaning roller  15  in the axial direction in this state is blocked by the flange  31   a  with no through hole as shown by an arrow j, and drops into the cleaning container  16  by gravitation. As a result, it is possible to suppress that the liquid developer reaches the bearing  30   a.    
     Next, in the case where the transfer unit  102 A shown in  FIG. 7  is in inclination, the cleaning roller  15  is inclined in a state in which an image forming operation is stopped. For this reason, the liquid developer on the surface of the cleaning roller  15  flows along the direction of gravitation and drops from a lowest portion of the roller portion  29   a , and is collected in the cleaning container  16  as shown by an arrow k. On the other hand, the liquid developer flowing from an upper portion of the cleaning roller  15  flows along the shaft portion  29   b  toward the bearing  30   a  in some instances before the liquid developer reaches the lowest portion of the roller portion  29   a . However, even in this case, the flange  31   a  is provided on the shaft portion  29   b  between the roller portion  29   a  and the bearing  30   a , and therefore, the liquid developer flowed as described above is blocked by the flange  31   a  as shown by an arrow  1 , and drops into the cleaning container  16  by gravitation. Accordingly, it is possible to suppress that the liquid developer reaches the bearing  30   a.    
     The liquid developer dropped in the cleaning container  16  as shown by the arrows k and  1  flows toward the discharge opening  26  along the surface of the bottom plate portion  25 . Then, the liquid developer discharged through the discharge opening  26  is stored in an unshown developer collecting container. 
     Thus, in the case of this embodiment, the cleaning container  16  is supported by the supporting unit  104 A, and therefore, it is possible to suppress the leakage of the liquid developer by a constitution in which the transfer unit  102 A is inclined. Further, the flange  31   a  is provided between the roller portion  29   a  and the bearing  30   a  of the cleaning roller  15 , and therefore, even when the cleaning roller  15  is inclined together with the transfer unit  102 A, it is possible to suppress that the liquid developer reaches the bearing  30   a . Incidentally, in order to suppress the leakage of the liquid developer when the transfer unit is inclined, the flange  31   a  is provided only on a rear side (rotation supporting side) with respect to the axial direction of the cleaning roller, and the flange may also be not provided on the front side. Further, as a matter of course, the flange  31   a  may also be provided on both sides of the cleaning roller. 
     Third Embodiment 
     A third embodiment will be described using  FIG. 8  to  FIG. 10 . In the above-described first and second embodiments, the constitution relating to the transfer cleaning portion  103  was principally described. On the other hand, in the case of this embodiment, a constitution relating to the primary transfer roller  11  as a contact roller contacting an inner peripheral surface of the intermediary transfer belt  10  will be described. Other constitutions and actions are similar to those in the above-described first and second embodiments, and therefore, as regards a redundant portion, the drawing and description will be omitted or briefly made, and the same reference numerals or symbols are added to the same constituent elements, and in the following, a portion different from the first and second embodiments will be principally described. 
     To the primary transfer roller  11 , as described above, in order to transfer the toner image on the photosensitive drum  3 , onto the intermediary transfer belt  10  at the primary transfer portion T 1 , the voltage (primary transfer bias) is applied (see  FIG. 1 ). Accordingly, the primary transfer roller  11  is energized from an energizing portion such as the toner source via the electrode member by being contacted to the electrode member. Here, when the liquid developer is deposited on a contact portion between the electrode member and the primary transfer roller  11 , there is a liability that electrical conductive failure is caused to occur. This point will be described using a comparison example of  FIG. 8 . 
     Comparison Example 
       FIG. 8  is a view showing a constitution of the primary transfer portion T 1  on an end portion side with respect to an axial direction of a primary transfer roller  11 A in a constitution of the comparison example. The primary transfer roller  11 A includes a contact roller portion  60   a  contacting the inner peripheral surface of the intermediary transfer belt  10  and an electroconductive shaft portion  60   b  which is provided at an end portion of the contact roller portion  60   a  and which is electroconductive. The electroconductive shaft portion  60   b  is supported by the supporting frames  200   a  and  200   b  (see parts (a) and (c) of FIG.  4 ) via bearings  61 . Further, to an end portion of the electroconductive shaft portion  60   b , an electrode member  62  connected to an unshown energizing portion is contacted. Further, the primary transfer roller  11 A is supplied with a voltage from the energizing portion via the electrode member  62 . 
     Here, in the case of using the liquid developer, there is a liability that the liquid developer drops from the image forming portion such as the photosensitive drum  3  positioned above the primary transfer roller  11 A. Further, when the dropped liquid developer is deposited on an electrode contact portion  62 A between the electrode member  62  and the electroconductive shaft portion  60   b , there is a liability that improper electroconductivity is caused to occur. For this reason, in the comparison example of  FIG. 8 , a portion above the electrode outside portion  62 A is covered with a cover member  63 . 
     However, there is a liability that the liquid developer dropped on the cover member  63  drops from an end portion of the cover member  63  onto the electroconductive shaft portion  60   b  and reaches the electrode contact portion  62 A along the electroconductive shaft portion  60   b . Accordingly, even when the portion above the electrode contact portion  62 A is simply covered with the cover member  63 , arrival of the liquid developer at the electrode contact portion  62 A cannot be prevented sufficiently. 
     Constitution of this Embodiment 
     Therefore, in this embodiment, as shown in  FIG. 9  and  FIG. 10 , a constitution in which the liquid developer does not readily reach the electrode contact portion is employed. As shown in  FIG. 9 , the primary transfer roller  11  is disposed so as to sandwich the intermediary transfer belt as the transfer member with the photosensitive drum  3 . Opposite end portions of the primary transfer roller  11  are rotatably supported by a pair of supporting frames  200   a  and  200   b  constituting a transfer unit  102 B, via bearings  71 , respectively. Further, the primary transfer roller  11  is, for example, pressed toward the intermediary transfer belt  10  by urging the bearings  71  by unshown springs. Further, the primary transfer roller  11  is rotated by rotation of the intermediary transfer belt  10 . In this embodiment, on the rear side (REAR) of the casing  110  (see parts (a) and (b) of  FIG. 3 ) of the image forming apparatus, an electrode member  72  for energizing the primary transfer roller  11  is provided. 
     Description will be specifically described using  FIG. 10 . The primary transfer roller  11  as a contact roller includes a contact roller portion  70   a  contacting the inner peripheral surface of the intermediary transfer belt  10  and includes electroconductive shaft portions  70   b  which are provided at end portions of the contact roller portion  70   a  and which are electroconductive. Further, the electroconductive shaft portions  70   b  of opposite ends of the contact roller portion  70   a  are rotatably supported by bearings  71 , respectively. An outer diameter of the electroconductive shaft portions  70   b  is constituted so as to be smaller than an outer diameter of the contact roller portion  70   a . By doing so, a creepage distance between the photosensitive drum  3  and the primary transfer roller  11  can be ensured.  FIG. 10  shows a structure of the casing  110  on a rear side. The intermediary transfer belt  10  projects at a widthwise end portion in the axial direction more than an end portion of the contact roller portion  70   a  with respect to the axial direction is. Accordingly, a rear side end portion  10   c  of the intermediary transfer belt  10  projects more than a rear side end portion of the contact roller portion  70   a  is, and in an illustrated example, a portion above the bearing  71  is covered by the projected portion of the intermediary transfer belt  10 . For this reason, it is possible to prevent drop of the liquid developer directly on the bearing  71 . 
     The rear side electroconductive shaft portion  70   b  is extended to a further rear side more than the rear side widthwise end portion  10   c  of the intermediary transfer belt  10  is, and to an end portion thereof, for example, an electrode member  72  as an electric contact portion formed by bending a metal plate having elasticity is elastically contacted. In this embodiment, a free end portion of the electrode member  72  contacts an end surface of the electroconductive shaft portion  70   b . The electrode member  72  is connected to an energizing portion  74 . Accordingly, the primary transfer roller  11  is supplied with a primary transfer bias (voltage) from the energizing portion  74  via the electrode member  72 . 
     When the electrode member  72  is seen from the widthwise direction of the intermediary transfer belt  10 , the electrode member  72  has a dimension such that the electrode member  72  is accommodated inside the intermediary transfer belt  10 . In order to suppress leakage of a current to a periphery of the intermediary transfer belt  10 , the end portion of the electrode member  72  is disposed so as not to be protruded to the outside of the intermediary transfer belt  10 . 
     Further, also in the case of this embodiment, at least a portion above an electrode contact portion  72 A where the electrode member  72  and the electroconductive shaft portion  70   b  contact each other is covered by a cover member  73 . Further, direct drop of the liquid developer onto the electrode contact portion  72 A from the image forming portion such as the photosensitive drum  3  positioned above the primary transfer roller  11  is prevented. 
     The cover member  73  is, for example, a plate-like member formed of a resin material. Such a cover member  73  includes a cover portion  73   a  covering the portion above the electrode contact portion  72 A and a bent portion  73   b  obtained by bending a rear side end portion of the cover portion  73   a  downward. The rear side end portion of the cover portion  73   a  is positioned further on a rear side than the end portion of the electroconductive shaft portion  70   b  is. That is, cover member  73  covers a portion above the end portion of the electroconductive shaft portion  70   b  on a side opposite from the contact roller portion  70   a . The bent portion  73   b  is extended so that a lower end thereof is positioned beyond the electrode contact portion  72 A by bending a rear side end portion of the cover portion  73   a . Accordingly, as seen from the axial direction, the electrode contact portion  72 A is covered by the bent portion  73   b.    
     In this embodiment, in addition to such a cover member  73 , at an end portion of the primary transfer roller  11 , a flange  75  as a restricting member for the cover member is provided. The flange  75  is provided, with respect to the axial direction of the primary transfer roller  11 , between a front side end portion  73   c  of the cover member  73  and the electrode contact portion  72 A, and restricts that the liquid developer reaches the electrode contact portion  72 A from the end portion  73   c  of the cover member  73 . 
     Particularly, in this embodiment, the electrode member is positioned on the rear side of the casing  110  where a rotation center of the transfer unit exists. For this reason, the flange  75  is positioned, with respect to the direction of gravitation, below the front side end portion  73   c  of the cover member  73  at the second position where the transfer unit is inclined during the maintenance or the like. 
     Such a flange  75  is provided on the electroconductive shaft portion  70   b  so as to project from the outer peripheral surface of the electroconductive shaft portion  70   b  in a radial direction. The flange  75  may be provided integrally with the electroconductive shaft portion  70   b , and separately, may also be provided by fixing a flange member to the electroconductive shaft portion  70   b  by press-fitting. In either case, the flange  75  restricts, as described later, that the liquid developer flows along the electroconductive shaft portion  70   b  and reaches the electrode contact portion  72 A. 
     The liquid developer dropped from the image forming portion such as the photosensitive drum  3  positioned above the primary transfer roller  11  drops into a region G between a position E of the electroconductive shaft portion  70   b  and a position F. The position E is a position below the end portion  73   c  of the cover member  73  with respect to the vertical direction, and the position F is a position below the rear side end portion  10   c , with respect to the widthwise direction, of the intermediary transfer belt  10  with respect to the vertical direction. More specifically, the position F is the position below the rear side end portion  10   c , with respect to the widthwise direction, of the intermediary transfer belt  10  with respect to the vertical direction when the intermediary transfer belt  10  shifts to a rearmost side during the image formation. Specifically, the liquid developer dropped on the cover member  73  flows along the cover member  73  and drops from the end portion  73   c  onto the position E of the electroconductive shaft portion  70   b . Further, the liquid developer on the intermediary transfer belt  10  flows along the surface of the intermediary transfer belt  10  and drops from the end portion  10   c  onto the position F of the electroconductive shaft portion  70   b . Further, the liquid developer also directly drops into the region G of the electroconductive shaft portion  70   b  without via the cover member  73  or the intermediary transfer belt  10  in some cases. 
     The liquid developer dropped in the region G in this manner moves in the axial direction along the surface of the electroconductive shaft portion  70   b  in some cases. However, in this embodiment, a flange  75  with no through hole is provided on the electroconductive shaft portion  70   b  between the region G and the electrode contact portion  72 A. For this reason, the liquid developer flowing along the surface of the electroconductive shaft portion  70   b  is blocked by the flange  75  and drops downward by gravitation, so that it is possible to suppress that the liquid developer reaches the electrode contact portion  72 A. Further, even in a state in which the transfer unit is inclined to the second position, similarly, the liquid developer flowing along the surface of the electroconductive shaft portion  70   b  is blocked by the flange  75  so that it is possible to suppress that the liquid developer reaches the electrode contact portion  72 A. 
     Further, the liquid developer dropped on the cover member  73  also drops from the rear side end portion of the cover member  73 . However, the rear side end portion of the cover member  73  is positioned on a rear side more than the electrode contact portion  72 A is, and therefore, even when the liquid developer drops from the rear side end portion of the cover member  73 , the liquid developer does not reach the electrode contact portion  72 A. Further, the electrode contact portion  72 A is covered by the bent portion  73   b  with respect to the axial direction, and therefore, it is possible to more reliably suppress that the liquid developer is deposited on the electrode contact portion  72 A from the rear side. 
     Incidentally, the cover portion  73   a  of the cover member  73  at least may only be required to cover the portion above the electrode contact portion  72 A, and the front side end portion  73   c  may only be required to be positioned on the front side more than the flange  75  is. However, the cover portion  73   a  may preferably cover above entirety of the flange  75 . That is, when the flange  75  is seen from above, the entirety of the flange  75  may preferably be covered by the cover portion  73   a.    
     By this, it is possible to suppress that the liquid developer dropped from a side end portion of the cover portion  73   a  is deposited on a rear side-side surface of the flange  75 . If the liquid developer is deposited on the rear side-side surface of the flange  75 , there is a possibility that the deposited liquid developer by rotation of the primary transfer roller  11  reaches the rear side further than the flange  75  is, and reaches the electrode contact portion  72 A. On the other hand, when the cover portion  73   a  covers above the entirety of the flange  75 , deposition of the liquid developer on the rear side-side surface of the flange  75  is suppressed, so that it is possible to suppress that the liquid developer reaches the electrode contact portion  72 A. 
     Further, the cover portion  73   a  of the cover member  73  may preferably cover above the entirety of the electrode member  72 . 
     Fourth Embodiment 
     A fourth embodiment will be described using parts (a) and (b) of  FIG. 11 . In the above-described third embodiment, the constitution in which the electrode member  72  is contacted to the end surface of the electroconductive shaft portion  70   b  was described. On the other hand, in this embodiment, an electrode member  720  is elastically contacted to a circumferential surface of the electroconductive shaft portion  70   b . Other constitutions and actions are similar to those in the above-described third embodiment, and therefore, as regards a redundant portion, the drawing and description will be omitted or briefly made, and the same reference numerals or symbols are added to the same constituent elements, and in the following, a portion different from the third embodiment will be principally described. 
     In part (a) of  FIG. 11 , a constitution of a first example of this embodiment is shown. In the case of this embodiment, a free end portion of the electrode member  720  is elastically contacted to the circumferential surface of the electroconductive shaft portion  70   b . Further, a cover member  730  covers at least above an electrode contact portion  720 A where the electrode member  720  and the electroconductive shaft portion  70   b  contact each other. Further, the flange  75  is provided between a front side end portion  730   a  of the cover member  730  and the electrode contact portion  720 A with respect to the axial direction of the primary transfer roller  11 . Further, the liquid developer is suppressed from reaching the electrode contact portion  720 A from the cover member  730 . 
     Incidentally, a rear side end portion  730   b  of the cover member  730  is positioned on a further rear side than a rear side end surface of the electroconductive shaft portion  70   b  is. However, in the case of the first example of this embodiment, on the rear side of the cover member  730 , the bent portion as in the third embodiment is not provided. 
     Also in such a case of the first example of this embodiment, the liquid developer dropped in the region G and flowed in the axial direction along the surface of the electroconductive shaft portion  70   b  is blocked by the flange  75  and is dropped downward by gravitation, so that it is possible to suppress that the liquid developer reaches the electrode contact portion  720 A. 
     Further, the rear side end portion  730   b  of the cover member  730  is positioned further on the rear side than the end surface of the electroconductive shaft portion  70   b  is, and therefore, even when the liquid developer drops from the rear side end portion of the cover member  730 , deposition of the liquid developer onto the electroconductive shaft portion  70   b  can be suppressed. If the liquid developer deposits on the electroconductive shaft portion  70   b  on the rear side of the electrode contact portion  720 A, the liquid developer flows in the axial direction also from this rear side in some cases. In the first example of this embodiment, also the portion above the rear side end surface of the electroconductive shaft portion  70   b  is covered by the cover member  730 , and therefore, it is possible to thus suppress that the liquid developer reaches the electrode contact portion  720 A from the rear side. 
     On the other hand, in a second example of this embodiment shown in part (b) of  FIG. 11 , a rear side end portion  731   b  of a cover member  731  covering a portion above the electrode contact portion  720 A is positioned further on a front side than an end surface of the electroconductive shaft portion  70   b  is. In the case of such a constitution, in addition to a front side flange  75  of the electrode contact portion  720 A, a flange  76  similar to the flange  75  is provided on the electroconductive shaft portion  70   b  on the rear side of the electrode contact portion  720 A. That is, with respect to the axial direction of the primary transfer roller  11 , the flange  76  is provided between the rear side end portion  731   b  of the cover member  731  and the electrode contact portion  720 A. The flange  75  is, similar to the first example of this embodiment, provided between a front side end portion  731   a  of the cover member  731  and the electrode contact portion  720 A. 
     In such a case of the second example of this embodiment, the liquid developer dropped from the rear side end portion  731   b  of the cover member  731  and flowed in the axial direction along the surface of the electroconductive shaft portion  70   b  is blocked by the flange  76  and drops downward by gravitation. As a result of this, it is possible to suppress that the liquid developer reaches the electrode contact portion  720 A from the rear side. 
     Fifth Embodiment 
     A fifth embodiment will be described using parts (a) and (b) of  FIG. 12 . In the above-described fourth embodiment, the constitution in which the electrode member  72  is contacted to the end surface of the electroconductive shaft portion  70   b  was described. On the other hand, in this embodiment, in such a constitution, entrance and deposition of the liquid developer onto bearings and gears can be suppressed. Other constitutions and actions are similar to those in the above-described fourth embodiment, and therefore, as regards a redundant portion, the drawing and description will be omitted or briefly made, and the same reference numerals or symbols are added to the same constituent elements, and in the following, a portion different from the fourth embodiment will be principally described. 
     As shown in part (a) of  FIG. 12 , in a first example of this embodiment, a bearing  710  supports the electroconductive shaft portion  70   b  on a side opposite from the front side end portion  730   a  of the cover member  730  while sandwiching the flange  75  between itself and the front side end portion  730   a  with respect to the axial direction of the primary transfer roller  11 . Further, the cover member  730  also covers a portion above the bearing  710 . Incidentally, also in the case of this embodiment, the rear side end portion  730   b  of the cover member  730  projects further toward a rear side than a rear side end surface of the electroconductive shaft portion  70   b  projects. 
     In such a case of this embodiment, the liquid developer dropped in the region G and flowed in the axial direction along the surface of the electroconductive shaft portion  70   b  is blocked by the flange  75  and is dropped downward by gravitation, so that it is possible to suppress that the liquid developer reaches the electrode contact portion  720 A and the bearing  710 . Further, the bearing  710  is covered by the cover member  730  at a portion above the bearing  710 . For this reason, it is possible to suppress that the liquid developer enters the bearing  710 . 
     On the other hand, in a second example of this embodiment shown in part (b) of  FIG. 12 , a gear  711  is provided on the electroconductive shaft portion  70   b  on a side opposite from the front side end portion  730   a  of the cover member  730  while sandwiching the flange  75  between itself and the front side end portion  730   a  with respect to the axial direction of the primary transfer roller  11 . Further, the cover member  730  also covers a portion above the bearing  710 . Incidentally, also in the case of this embodiment, the rear side end portion  730   b  of the cover member  730  projects further toward a rear side than a rear side end surface of the electroconductive shaft portion  70   b  projects. 
     The gear  711  is connected to a drive transmitting portion to which rotational drive from an unshown driving source such as a motor is transmitted. When the liquid developer enters or deposits on the drive transmitting portion including the gear  711  via such a gear  711 , there is a possibility that an improper operation is caused. For this reason, by disposing the gear  711  as in this embodiment, entrance or deposition of the liquid developer onto the gear  711  is suppressed. 
     That is, the liquid developer dropped in the region G and flowed in the axial direction along the surface of the electroconductive shaft portion  70   b  is blocked by the flange  75  and is dropped downward by gravitation, so that it is possible to suppress that the liquid developer reaches the gear  711 . Further, the gear  711  is covered by the cover member  730  at a portion above the gear  711 . For this reason, it is possible to suppress that the liquid developer enters or deposits onto the drive transmitting portion including the gear  711 , via the gear  711 . Incidentally, the rotation transmitting member may also be, for example, a pulley other than the gear. 
     Incidentally, a positional relationship between the gear or the rotation transmitting member and the electrode contact portion with respect to the axial direction may also be opposite to those of parts (a) and (b) of  FIG. 12 . Further, in this embodiment, the bearing  71  is disposed inside the flange  75  with respect to the axial direction, but may also be disposed outside the flange  75 . 
     Sixth Embodiment 
     A sixth embodiment will be described using parts (a) and (b) of  FIG. 13 . In the above-described third embodiment, the constitution in which the cover member  73  and the intermediary transfer belt  10  do not overlap with each other was described. On the other hand, in this embodiment, a cover member  732  and the intermediary transfer belt  10  are caused to partially overlap with each other. Further, the bearing  710  is disposed below the cover member  732 . Other constitutions and actions are similar to those in the above-described third embodiment, and therefore, as regards a redundant portion, the drawing and description will be omitted or briefly made, and the same reference numerals or symbols are added to the same constituent elements, and in the following, a portion different from the third embodiment will be principally described. 
     In part (a) of  FIG. 13 , a constitution of a first example of this embodiment is shown. In the first example, the cover member  732  is disposed so that a roller portion side (front side) end portion  732   c  is positioned below a portion of the intermediary transfer belt  10  projected more than the end portion of the contact roller portion  70   a  is. That is, compared with the constitution of the third embodiment shown in  FIG. 10 , the cover portion  732   a  of the cover member  732  is extended toward the intermediary transfer belt  10  side, and an extended free end portion is caused to enter an inside of the intermediary transfer belt  10 . By this, a front side portion of the cover member  732  and a front side portion of the intermediary transfer belt  10  are caused to overlap with each other with respect to the up-down direction. Incidentally, a structure of the rear side bent portion  732   b  of the cover member  732  is the same as that in the third embodiment. 
     Thus, by causing the cover member  732  and the intermediary transfer belt  10  to partially overlap with each other, it is possible to restrict a range in which the liquid developer drops onto the electroconductive shaft portion  70   b  from the cover member  732  and the intermediary transfer belt  10 . In the case of the first example of this embodiment, as shown in part (a) of  FIG. 13 , the liquid developer moved on the surface of the intermediary transfer belt  10  drops onto the cover member  732  from the end portion  10   c . For this reason, a drop range of the liquid developer onto the electroconductive shaft portion  70   b  can be restricted to a position H below the front side end portion  732   c  of the cover member  732 . 
     On the other hand, in part (b) of  FIG. 13 , a constitution of a second example of this embodiment is shown. In the first example, the cover member  732  is disposed so that a roller portion side (front side) end portion  732   c  is positioned above a portion of the intermediary transfer belt  10  projected more than the end portion of the contact roller portion  70   a  is. That is, compared with the constitution of the third embodiment shown in  FIG. 10 , the cover portion  732   a  of the cover member  732  is extended toward the intermediary transfer belt  10  side, and an extended free end portion is caused to enter an outside of the intermediary transfer belt  10 . By this, a front side portion of the cover member  732  and a front side portion of the intermediary transfer belt  10  are caused to overlap with each other with respect to the up-down direction. 
     Further, in the second example of this embodiment, the flange  75  is positioned, in a second position where the transfer unit is inclined during maintenance or the like, below the rear side end portion  10   c  of the intermediary transfer belt  10  with respect to the direction of gravitation. For this reason, even in a state in which the transfer unit is inclined to the second position, the liquid developer flowing along the surface of the electroconductive shaft portion  70   b  is blocked, so that it is possible to suppress that the liquid developer reaches the electrode contact portion  72 A. 
     In the case of the second example of this embodiment, as shown in part (b) of  FIG. 13 , the liquid developer moved on the surface of the cover member  732  drops onto the intermediary transfer belt  10  from the end portion  732   c . For this reason, a drop range of the liquid developer onto the electroconductive shaft portion  70   b  can be restricted to a position L below the rear side end portion  10   c  of the intermediary transfer belt  10 . 
     Further, in either case of the first example and the second example of this embodiment, the flange  75  is provided between the position H where the liquid developer drops and the electrode contact portion  72 A and between the position I where the liquid drops and the bearing  710 . By this, it is possible to efficiently suppress that the liquid developer dropped on the electroconductive shaft portion  70   b  reaches the electrode contact portion  72 A and the bearing  710 . 
     Seventh Embodiment 
     A seventh embodiment will be described using  FIG. 14 . In the above-described third embodiment, the constitution in which the portion above the electrode contact portion  72 A is covered by the cover member  73  was described. On the other hand, in this embodiment, a portion above an electrode contact portion  720 A is covered by the intermediary transfer belt  10 A. Incidentally, an electrode member  720  contacts a circumferential surface of the electroconductive shaft portion  70   b  at the electrode contact portion  720 A similarly as in the above-described fourth embodiment. Other constitutions and actions are similar to those in the above-described third or fourth embodiment, and therefore, as regards a redundant portion, the drawing and description will be omitted or briefly made, and the same reference numerals or symbols are added to the same constituent elements, and in the following, a portion different from the third or fourth embodiment will be principally described. 
     In the case of this embodiment, the contact roller portion  70   a  of the primary transfer roller  11  contacts the intermediary transfer belt  10  further inside than the location of an end portion  10 Ac of the intermediary transfer belt  10 . In other words, the rear side end portion  10 Ac of the intermediary transfer belt  10  with respect to the intermediary transfer belt  10 A projects further in the axial direction than the end portion of the contact roller portion  70   a  with respect to the axial direction does. 
     Further, the electrode member  720  contacts the electroconductive shaft portion  70   b  below the portion of the intermediary transfer belt  10 A projected more than the contact roller portion  70   a  is. In other words, a portion above the electrode contact portion  720 A where the electrode member  720  and the electroconductive shaft portion  70   b  contact each other is covered by a part of the intermediary transfer belt  10 A. 
     Further, in this embodiment, at an end portion of the primary transfer roller  11 , a flange  77  as a restricting member for the belt is provided. The flange  77  is provided, with respect to the axial direction of the primary transfer roller  11 , between a front side end portion  10 Ac of the intermediary transfer belt  10 A with respect to the widthwise direction and the electrode contact portion  720 A, and restricts that the liquid developer reaches the electrode contact portion  720 A from the end portion  10 Ac of the intermediary transfer belt  10 A. The flange  77  has the same constitution as that of the flange  75  in the third embodiment. 
     Accordingly, in this embodiment, the electrode contact portion  720 A is disposed between the contact roller portion  70   a  and the flange  77 . The bearing  710  is provided at an end portion of the electroconductive shaft portion  70   b . Further, a portion above the electrode contact portion  720 A and the flange  77  is covered by a portion of the intermediary transfer belt  10 A projected from the contact roller portion  70   a.    
     In such a case of this embodiment, the liquid developer on the intermediary transfer belt  10 A flows along the surface of the intermediary transfer belt  10 A and drops onto a position J of the electroconductive shaft portion  70   b  from the end portion  10 Ac. The position J is a position below the end portion  10 Ac of the intermediary transfer belt  10 A with respect to the vertical direction. 
     The liquid developer dropped in the position J in this manner moves in the axial direction along the surface of the electroconductive shaft portion  70   b  in some cases. However, in this embodiment, the flange  77  with no through hole is provided on the electroconductive shaft portion  70   b  between the position J and the electrode contact portion  720 A. For this reason, the liquid developer flowing along the surface of the electroconductive shaft portion  70   b  is blocked by the flange  77  and drops downward by gravitation, so that it is possible to suppress that the liquid developer reaches the electrode contact portion  720 A. 
     Further, the contact portion  720 A is positioned further on the front side than the position J, and therefore, in a state in which the transfer unit is inclined to a second position, the electrode contact portion  720 A is positioned above the position J with respect to the direction of gravitation. For this reason, in this state, it is possible to suppress that the liquid developer dropped on the electroconductive shaft portion  70   b  reaches the electrode contact portion  720 A. 
     Other Embodiments 
     In the above-described first and second embodiments, a constitution in which at least the cleaning container  16  is supported by the supporting units  104  and  104 A was described. However, other than the cleaning container  16 , for example, a container for collecting the liquid developer dropped from the surface of the intermediary transfer belt, or the like may also be supported by the holding members such as the supporting units  104  and  104 A or the like. 
     That is, a collecting portion capable of collecting the liquid developer dropped from at least a part of the transfer unit may also be supported by the holding members such as the supporting units  104  and  104 A or the like. By thus-constituting the collecting portion, even when the transfer unit is inclined during the maintenance, it is possible to suppress that the liquid developer leaks to an unintended portion. 
     Further, in the above-described third to seventh embodiments, the constitution in which the electrode member is contacted to the electroconductive shaft portion and energization is carried out was described. However, the energizing constitution may also be, for example, a constitution using a member slidable with the electroconductive shaft portion, such as a constitution utilizing a bearing member for supporting the electroconductive shaft portion. 
     Further, the contact roller may also be, other than the primary transfer roller  11 , for example, the secondary transfer outer roller  12   b  or the cleaning roller  15  or the like. That is, if the contact roller is a roller which contacts the intermediary transfer belt and to which the voltage is applied, the constitutions of the above-described third and seventh embodiments are similarly applicable to the rollers. Incidentally, in the case of a constitution in which the voltage is applied to the secondary transfer inner roller  12   a , the above-described constitution may preferably be applied to the secondary transfer inner roller  12   a . Further, the electrode member may also be used for connection required for electrical conduction, for example, grounding connection, in addition to connection to the energizing portion such as the high-voltage source. Further, the roller to be provided with the flange portion may also be the photosensitive drum  3  in addition to the above-described rollers. Further, the roller may also be rollers contacting the photosensitive drum  3 , for example, the developing roller for developing the latent image formed on the photosensitive drum  3  and the charging roller for electrically charging the photosensitive drum  3 . 
     Further, in the above-described third to seventh embodiments, the constitution in which the transfer unit as described in the first embodiment is inclined to the second position was described. However, the third to seventh embodiments are also applicable to the constitution in which the transfer unit is in the first position as it is in the first embodiment. Incidentally, the above-described respective embodiments are capable of being carried out appropriately in combination. Further, from the viewpoint of suppressing leakage of the liquid developer when the transfer unit is inclined, the flange may also have a constitution in which the flange is provided only on an apparatus rear side (rotation supporting point side of the transfer unit) with respect to the axial direction of the primary transfer roller. 
     INDUSTRIAL APPLICABILITY 
     According to the present invention, there is provided an image forming apparatus in which leakage of the liquid developer is capable of being suppressed in a constitution in which the transfer unit is inclined.