Patent Publication Number: US-2021191306-A1

Title: Recording medium conveyance device and image forming apparatus incorporating the recording medium conveyance device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This patent application is based on and claims priority pursuant to 35 U.S.C. § 119 to Japanese Patent Application No. 2019-232875, filed on Dec. 24, 2019 in the Japan Patent Office, the entire disclosure of which is hereby incorporated by reference herein. 
     BACKGROUND 
     Technical Field 
     Embodiments of the present disclosure generally relate to a recording medium conveyance device and an image forming apparatus incorporating the recording medium conveyance device. 
     Background Art 
     Some image forming apparatuses such as copiers, printers, and facsimiles include a vertical conveyance device that vertically conveys a recording medium (hereinafter, also referred to as “sheet”) from a sheet feeder to an image forming section. Such an image forming apparatus includes a cover that covers a sheet conveyance passage and is openable to facilitate jam processing. 
     SUMMARY 
     This specification describes an improved recording medium conveyance device that includes a conveyance device cover, a pair of guides, a maintenance part, a removable cover. The conveyance device cover is openable and covers a conveyance passage of a recording medium. The pair of guides forms the conveyance passage and includes a cover side guide on the conveyance device cover and a body side guide separable from the cover side guide. The maintenance part is on at least one of the pair of guides. The removable cover is configured to form a part of the conveyance passage and cover the maintenance part. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The aforementioned and other aspects, features, and advantages of the present disclosure would be better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: 
         FIG. 1  is a schematic view illustrating an image forming apparatus according to an embodiment of the present disclosure; 
         FIG. 2  is a schematic view illustrating an image forming apparatus of  FIG. 1  when a conveyance device cover is opened; 
         FIG. 3  is an exploded perspective view illustrating a maintenance part, a cover of the maintenance part, and a guide to which the maintenance part and the cover are fixed according to an embodiment of the present disclosure; 
         FIG. 4  is a schematic cross-sectional view illustrating an example of the cover attached to the guide in a different way from the cover in  FIG. 3 ; 
         FIG. 5  is a schematic cross-sectional view illustrating another example of the cover attached to the guide in a different way from  FIGS. 3 and 4 ; 
         FIG. 6  is a schematic cross-sectional view of a vertical configuration of a conveyance passage according to an embodiment of the present disclosure; 
         FIG. 7  is a perspective view of a guide on an image forming apparatus side in the conveyance passage of  FIG. 6 ; 
         FIG. 8  is a perspective view illustrating a part of the conveyance passage of  FIG. 6 ; 
         FIG. 9  is a schematic cross-sectional view of a vertical configuration of a conveyance passage according to an embodiment of the present disclosure; 
         FIG. 10  is a schematic cross-sectional view of a vertical configuration of a conveyance passage according to an embodiment of the present disclosure; 
         FIG. 11  is a perspective view illustrating the guide to which the cover is not attached; 
         FIG. 12  is a perspective view illustrating the cover and rollers of a conveyance roller pair; 
         FIG. 13  is a schematic cross-sectional view of the guide, the rollers of the conveyance roller pair, and the cover in a recording medium conveyance direction; and 
         FIG. 14  is a schematic cross-sectional view illustrating still another example of the cover attached to the guide according to an embodiment of the present disclosure. 
     
    
    
     The accompanying drawings are intended to depict embodiments of the present disclosure and should not be interpreted to limit the scope thereof. The accompanying drawings are not to be considered as drawn to scale unless explicitly noted. 
     DETAILED DESCRIPTION 
     In describing embodiments illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the disclosure of this specification is not intended to be limited to the specific terminology so selected and it is to be understood that each specific element includes all technical equivalents that have a similar function, operate in a similar manner, and achieve a similar result. 
     Although the embodiments are described with technical limitations with reference to the attached drawings, such description is not intended to limit the scope of the disclosure, and all of the components or elements described in the embodiments of this disclosure are not necessarily indispensable. 
     A description is provided of a recording medium conveyance device according to the present disclosure and an image forming apparatus incorporating the recording medium conveyance device with reference to drawings. It is to be noted that the present disclosure is not to be considered limited to the following embodiments, but can be changed within the range that can be conceived of by those skilled in the art, such as other embodiments, additions, modifications, deletions, and the scope of the present disclosure encompasses any aspect, as long as the aspect achieves the operation and advantageous effect of the present disclosure. 
     With reference to  FIGS. 1 and 2 , the image forming apparatus is described. 
       FIGS. 1 and 2  are schematic views illustrating the image forming apparatus including the recording medium conveyance device according to the present embodiment and illustrate a recording medium conveyance passage. Recording media are set in a recording media tray  1 . Hereinafter, the recording medium is also simply referred to as a “sheet”. A feed roller  2  separates the sheet from the sheets in the recording media tray  1  and feeds the sheet to a registration roller pair  3 . After the registration roller pair  3  holds the sheet for a predetermined time, the sheet is conveyed to an image forming section  4 , and an image is transferred to the sheet in the image forming section  4 . The image forming section  4  includes a transfer belt  41  and a transfer roller  42 . 
     Next, the sheet is conveyed to a fixing device  5  to fix the image transferred to the sheet, and after the transferred image is fixed onto the sheet, the sheet passes through a conveyance roller pair  6  and is conveyed to a sheet ejection device  10  or a reverse unit  9 . The conveyance roller pair  6  includes drive rollers  61  and driven rollers  62 . 
     A bifurcating claw  8  switches whether the sheet which the image is fixed is conveyed to the sheet ejection device  10  or the reverse unit  9 . In the recording medium conveyance device according to the present embodiment, the bifurcating claw  8  at a position  8   a  leads the sheet to the sheet ejection device  10 , and the bifurcating claw  8  at a position  8   b  leads the sheet to the reverse unit  9 . The bifurcating claw  8  is described later. 
     The sheet ejection device  10  ejects the sheet to a sheet ejection tray  200 . The ejected sheet may be conveyed to a post-processing peripheral device such as a stapler to perform post-processing such as binding processing, sheet folding processing. 
     On the other hand, in the reverse unit  9 , after a reverse roller pair  19  rotates in forward, the reverse roller pair  19  rotates in reverse to convey the sheet to a duplex copy unit. In the image forming apparatus of the present embodiment, a duplex copy entrance roller pair  12 , a duplex copy relay roller pair  13 , and a duplex copy exit roller pair  14  convey the sheet to the registration roller pair  3  again. 
     Downstream from the conveyance roller pair  6 , a sheet ejection sensor  7  serving as a recording medium detector is disposed. The sheet ejection sensor  7  detects the sheet to output a trigger signal for switching the position of the bifurcating claw  8  or starting drive of the reverse roller pair  19  in the reverse unit  9  or the ejection roller pair  11  in the sheet ejection device  10 . 
     As illustrated in  FIG. 2 , a conveyance device cover  50  is opened toward outside of the image forming apparatus body  40  to expose a conveyance passage in which the sheet is conveyed in a vertical direction. In  FIG. 2 , the sheet conveyance passage is from the registration roller pair  3  to the bifurcating claw  8 . Exposing the conveyance passage enables easily performing jam processing or maintenance works for parts disposed on the conveyance passage. Note that  FIG. 2  illustrates an example in which the conveyance device cover  50  is integrally rotated in the vertical direction to expose the conveyance passage, but the mode of rotation is not limited to this. 
     Next, the recording medium conveyance device is described. 
     The image forming apparatus of the present embodiment includes the recording medium conveyance device according to the present embodiment of the present disclosure to form the above-described conveyance passage for the recording medium (the sheet). 
     The recording medium conveyance device of the present embodiment includes a pair of guides to form the conveyance passage for the recording medium, a roller to convey the recording medium along the conveyance passage, and the conveyance device cover  50  that is disposed on a side face of the image forming apparatus body  40  to be able to open and close. The conveyance device cover  50  covers a part of the conveyance passage. 
     The conveyance device cover  50  can rotate to the outside of the image forming apparatus body  40  about a shaft parallel to the rotation axis of the roller (for example, the conveyance roller pair  6  in  FIG. 1 ). 
     The pair of guides includes a guide on an image forming apparatus body side that is referred to as a body side guide and a guide on a conveyance device cover side that is referred to as a cover side guide. At least one of the body side guide and the cover side guide includes a maintenance part to be maintained and a cover that covers the maintenance part and forms the conveyance passage. 
     In the above-described configuration, removing the cover enables easy access to the maintenance part, attaching the maintenance part to the guide, and detaching the maintenance part from the guide. In addition, the cover forming a part of the guide reduces the number of parts and the number of work processes such as manufacturing processes and improves workability. 
       FIG. 3  is an exploded perspective view illustrating the maintenance part, the cover of the maintenance part, and the guide to which the maintenance part and the cover are fixed. The guide illustrated in  FIG. 3  is the body side guide  20 . Examples of the maintenance parts include parts to be maintained, such as rollers and electrical parts. 
     With reference to  FIG. 3 , the following describes an embodiment in which the maintenance part is an electrical part, specifically, a recording medium detector to detect the recording medium. The recording medium detector is also referred to as a sheet ejection sensor. The sheet ejection sensor  7  and a bracket  112  constitute a sheet ejection detecting device. A harness is connected to the sheet ejection sensor  7 . 
     The bracket  112  has positioning holes  112   a  and  112   b  and a screwing hole  112   c  that may be a through hole or a threaded hole. The body side guide  20  includes bosses  21   a  and  21   b . The boss  21   a  is inserted into the positioning hole  112   a , the boss  21   b  is inserted into the positioning hole  112   b , and the bracket  112  is positioned. The body side guide  20  includes a threaded hole  21   c  that communicates with the screwing hole  112   c  of the bracket  112 , and a screw fixies the bracket  112  to the body side guide  20 . 
     The cover  100  (hereinafter, also referred to as a “sensor cover  100 ”) is a removable member that covers the sheet ejection detecting device and forms the conveyance passage. The sensor cover  100  has a window  104  overlapping the sheet ejection sensor  7 , positioning holes  102   a  and  102   b , and screwing holes  103   a  and  103   b . The positioning hole  102   a  is an elongated hole, and the positioning hole  102   b  mainly positions the sensor cover  100 . The screwing holes  103   a  and  103   b  may be threaded holes or through holes. 
     The body side guide  20  includes positioning pins  22   a  and  22   b . The positioning pin  22   a  is inserted into the positioning hole  102   a , the positioning pin  22   b  is inserted into the positioning hole  102   b , and the sensor cover  100  is positioned. The body side guide  20  includes threaded holes  23   a  and  23   b  that communicate with the screwing holes  103   a  and  103   b , respectively, of the sensor cover  100 , and screws fix the sensor cover  100  to the body side guide  20 . 
       FIGS. 4 and 5  are schematic cross-sectional views illustrating the cover  100  attached to the body side guide  20  in different ways form the above-described cover  100 . In the embodiment illustrated in  FIG. 4 , the sensor cover  100  includes detents  105   a  and  105   b  and a screwing hole  103   c . The body side guide  20  includes positioning holes  25   a  and  25   b . The detents  105   a  and  105   b  of the sensor cover  100  are fitted to the positioning holes  25   a  and  25   b , respectively. The body side guide  20  includes a threaded hole  23   c  that communicates with the screwing hole  103   c  of the sensor cover  100 , and a screw  53  fixies the sensor cover  100  to the body side guide  20 . Reducing the number of fixing points with screws improves workability. 
     In the embodiment illustrated in  FIG. 5 , the sensor cover  100  includes a coupling part  101  and an elastic fixing member  106  having elasticity and a U-shaped cross-section. 
     The body side guide  20  includes a positioning hole  26   a . The elastic fixing member  106  of the sensor cover  100  is inserted into the positioning hole  26   a , and a fixing projection  106   a  of the elastic fixing member  106  fixes the elastic fixing member  106  on the body side guide  20 . The body side guide  20  includes a positioning hole  26   b . The coupling part  101  is inserted into and fitted to the positioning hole  26   b  of the body side guide  20  to fix the sensor cover  100  on the body side guide  20 . 
     The conveyance device in the embodiment of  FIG. 5  can be easily handled even when the space for attaching and detaching the sheet ejection sensor  7  is small (for example, when the conveyance device cover  50  rotates in a narrow range and forms a narrow opening angle) because the sensor cover  100  is attached to the body side guide  20  without using the screw. 
       FIG. 14  is a schematic cross-sectional view illustrating an embodiment in which the bracket  112  is set on the sensor cover  100 . Other than a configuration to fix the bracket  112  on the sensor cover  100 , a configuration in  FIG. 14  are similar to the configuration in  FIG. 5 . 
     In the embodiment illustrated in  FIG. 14 , the bracket  112  is disposed on the sensor cover  100  so that a screwing hole  112   d  of the bracket  112  communicates with the threaded hole  109  disposed inside the sensor cover  100 , and a screw  51  fastens the bracket  112  to the sensor cover  100 . 
     In the embodiments of  FIGS. 3 to 5 , after the detachable sensor cover  100  is removed, the bracket  112  attached to the body side guide  20  is removed from the body side guide  20 . In contrast, in the embodiment illustrated in  FIG. 14 , after the sensor cover  100  is removed from the body side guide  20 , the bracket  112  is removed from the sensor cover  100 . That is, since the work of removing the bracket  112  from the sensor cover  100  can be performed at an arbitrary place outside the image forming apparatus, workability is improved. 
     As described above, it is preferable that the maintenance part is integrally attached to the cover. The above-described configuration can improve the workability and accuracy for positioning the maintenance part attached to the cover. In addition, since the above-described configuration can reduce the number of parts, the above-described configuration can reduce the accumulation of tolerance as well as the cost. 
       FIG. 11  is a perspective view illustrating the body side guide  20  to which the cover  100  is not attached. 
     As illustrated in  FIG. 11 , the body side guide  20  incudes drive rollers  61  of the conveyance roller pair  6  (that is, drive rollers  61   a  and  61   b ). In addition, the body side guide  20  has mounting holes  27  to set a conveyance roller rotation shaft  63  on both side faces of the body side guide  20  in a width direction. 
     Since the plurality of members are integrally formed as described above, the positioning accuracy and the mounting accuracy can be improved. 
     The cover  100  (that is, the sensor cover  100 ) is disposed near and downstream from the drive rollers  61  of the conveyance roller pair  6  in a recording medium conveyance direction. As illustrated in  FIGS. 3 and 10 , scoops  107  are preferably formed on the cover  100 . When the scoop  107  is disposed downstream from a roller, forming the scoop  107  on the cover  100  improves the positional accuracy between the scoop  107  and the roller. 
       FIG. 10  is a schematic vertical cross-sectional view to describe the scoop  107 . An end portion of the cover  100  may catch the recording medium conveyed on the conveyance passage and cause a jam. To prevent such a jam, the scoop  107  is formed so that the end portion of the cover  100  is curved so as to be separated from a surface forming the conveyance passage. The scoop  107  integrally formed with the cover  100  can reduce the number of parts. 
     With reference to  FIG. 7 , the body side guide  20  to form the conveyance passage in the image forming apparatus side is described. 
     The body side guide  20  includes a first guide member  20   a  on a lower portion than the cover  100  in a vertical direction and a second guide member  20   b  on an upper portion than the cover  100  in the vertical direction. That is, in the recording medium conveyance direction, the first guide member  20   a  is disposed upstream from the cover  100 , and the second guide member  20   b  is disposed downstream from the cover  100 . 
     Each of the first guide member  20   a , the second guide member  20   b , and the cover  100  includes a plurality of ribs extending in the recording medium conveyance direction. Each of the first guide member  20   a , the second guide member  20   b , and the cover  100  may include a plurality of convex portions extending in the recording medium conveyance direction. The plurality of ribs is an example of the plurality of convex portions. The cover  100  has notches  105  (see  FIG. 3 ). The notch  105  can accommodate at least a part of a rib  208  of the second guide member  20   b.    
     As illustrated in  FIG. 7 , a plurality of ribs is formed at intervals in a direction orthogonal to the recording medium conveyance direction. Each of the ribs  208  in the second guide member  20   b  is disposed along a direction of a line extended from each of the ribs  108  of the cover  100  and a direction of a line extended from each of the ribs  28  of the first guide member  20   a , respectively. The plurality of ribs forms the surface of the conveyance passage and enables smooth conveyance of the recording medium. 
     The second guide member  20   b  is formed on a swing member to swing so that each of the ribs  208  enter and exit from the notch  105  of the cover  100 . In the present embodiment, the swing member is the bifurcating claw  8  to switch the conveyance passage of the recording medium. 
       FIG. 6  is a schematic cross-sectional view of a vertical configuration of the conveyance passage. 
     After the recording medium passes through the fixing device  5  (see  FIG. 1 ), the recording medium passes through the conveyance roller pair  6 , passes between the pair of guides including the body side guide  20  and the cover side guide  120 , and reaches the bifurcating claw  8 . 
     The bifurcating claw  8  at the position  8   a  in  FIG. 6  leads the recording medium to a sheet ejection passage  130 . In contrast, the bifurcating claw  8  at the position  8   b  in  FIG. 6  leads the recording medium to a reverse passage  135 . The recording medium is sent from the reverse passage  135  to the reverse unit  9 . In the reverse unit  9 , the reverse roller pair  19  rotates forward to convey the recording medium by a predetermined amount and rotates in reverse to convey the recording medium to a duplex copy passage  136 . 
     As illustrated in  FIGS. 3 and 7 , the cover  100  has five notches  105 . As illustrated in  FIGS. 6 and 7 , the bifurcating claw  8  at the position  8   b  is in the notch  105 . The bifurcating claw  8  swings so as to protrude to the outside of the notch  105  at the position of  8   a.    
     The notch  105  eliminates the need for another part to connect the conveyance passage between the bifurcating claw  8  and the cover  100  and enables downsizing the recording medium conveyance device. In addition, the notch  105  enables arranging the sheet ejection sensor  7  closer to the bifurcating claw  8 , which improves the detection performance of the sheet ejection sensor  7 . The number of notches  105  accommodating the bifurcating claw  8  is not limited to five in the present embodiment and can be appropriately set. 
       FIGS. 8 and 9  illustrate an arrangement of the ribs  28  of the first guide member  20   a  and the ribs  108  of the cover  100 .  FIG. 8  is a perspective view illustrating a part of the conveyance passage, and  FIG. 9  is a schematic cross-sectional view of the vertical configuration of the conveyance passage. 
     In the recording medium conveyance direction, the rib  108  of the cover  100  downstream the first guide member  20   a  extends toward upstream from the rib  28  of the first guide member  20   a . The height of the rib  108  in the cover  100  is lower than the height of the rib  28  of the first guide member  20   a . That is, the top surface of the rib  108  is farther from the surface of the conveyance passage than the top surface of the rib  28 . Setting the top surface of rib disposed on downstream side farther from the surface of the conveyance passage than the top surface of rib disposed on upstream side can prevent the occurrence of jam caused by the recording medium caught by the rib on the downstream side. 
     Preferably, the cover  100  has a surface along the conveyance passage of the recording medium.  FIGS. 9 and 10  are schematic cross-sectional views of the vertical configuration of the conveyance passage. The cover  100  in the present embodiment has a curved surface along the surface of the conveyance passage as illustrated in  FIGS. 9 and 10 . When a part having a curved surface is downstream from the recording medium detector in the conveyance passage or when the bifurcating claw  8  has a curved surface facing the surface of the conveyance passage, the cover  100  having a surface shape along the curved surface can downsize the recording medium conveyance device. 
     The sheet ejection sensor  7  is easily affected by contamination by paper dust or the like in the image forming apparatus and is frequently maintained. According to the recording medium conveyance device of the present embodiment described above, removing the cover  100  on the conveyance passage enables easy access to the sheet ejection sensor  7  and improves the workability during replacement or maintenance. Therefore, the downtime of the image forming apparatus can be reduced, which improves the productivity. 
     Additionally, the cover  100  having a shape that enables arranging the cover  100  close to the bifurcating claw  8  can set the position of the sheet ejection sensor  7  accommodated in the cover  100  close to the bifurcating claw  8 , and both improvement of detection accuracy and space saving can be achieved. 
     In the above-described embodiments, the maintenance part is the recording medium detector that is the sheet ejection sensor  7 , but the maintenance part is not limited to this. 
     With reference to  FIGS. 12 and 13 , another embodiment is described. In the embodiment, the driven rollers  62  of the conveyance roller pair  6  are the maintenance parts disposed on the cover side guide  120 .  FIG. 12  is a perspective view illustrating the cover and the driven rollers  62  of the conveyance roller pair  6 .  FIG. 13  is a schematic cross-sectional view of the guide, the driven rollers  62  of the conveyance roller pair  6  and the cover in the recording medium conveyance direction. 
     As illustrated in  FIG. 12 , a roller cover  140  as the cover covers the driven rollers  62  of the conveyance roller pair  6  (that is, the driven rollers  62   a  and  62   b ) and exposes contact surfaces of the driven rollers  62  of the conveyance roller pair  6  that contact the recording medium. 
     As illustrated in  FIG. 13 , a shaft  64  supports the driven rollers  62  of the conveyance roller pair  6  (that is, the driven rollers  62   a  and  62   b ), and pressure springs  80  (that is, pressure springs  80   a  and  80   b ) press the shaft  64 . The roller cover  140  is detachably attached to the cover side guide  120  by screws  52  (that is, screws  52   a  and  52   b ). Removing the roller cover  140  enables easy access to the driven rollers  62  of the conveyance roller pair  6  and the shaft  64  and easy maintenance and replacement. 
     The above-described embodiments are illustrative and do not limit the present disclosure. Thus, numerous additional modifications and variations are possible in light of the above teachings. It is therefore to be understood that within the scope of the present disclosure, the present disclosure may be practiced otherwise than as specifically described herein. Further, features of components of the embodiments, such as the number, the position, and the shape are not limited the embodiments and thus may be preferably set.