JP2007331887A - Image forming device and sheet material feeding device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that detection of a rear end of a fed sheet material is delayed and waste stopping of a device body or the like occurs when feeding of the sheet material is performed from a manual insertion paper feeding tray capable of storing the sheet material of a plurality of sizes. <P>SOLUTION: A rear end detection device 16 is arranged on the outside of a frame 31 of the device body and in the manual insertion paper feeding tray 2, and a roller 22 as a rotation member contacted with the sheet material P and capable of being rotated together by moving the sheet material P is rotatably retained on the frame 21 of the rear end detection device 16. A slit wheel 24 formed with slits in an approximately radial form is mounted to one end of a support shaft 23 of the roller 22, and a rear end detection sensor 25 is arranged in order to detect the slit of the slit wheel 24. The rear end of the fed sheet material P is passed through the roller 22 and the roller 22 is stopped to detect the rear end of the sheet material P. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus and a sheet material feeding apparatus.

  As an image forming apparatus such as a printer, a facsimile machine, a copying machine, and a composite machine of these, for example, an ink jet recording apparatus as an image forming apparatus of a liquid discharge recording method using a recording head that discharges recording liquid droplets, an electrophotographic process The image forming apparatus used is known.

  In such an image forming apparatus, paper as a fed sheet material (the material is not limited to paper, but includes OHP, etc., and ink droplets, other liquids, developer such as toner, etc. can be attached. In other words, a transfer paper, a recording medium, a recording medium, a recording paper, a recording paper, and the like are also synonymous.) May be jammed during conveyance. This jam is particularly caused by a paper setting error or a user size setting error.

  Therefore, in an electrophotographic image forming apparatus using the secondary transfer method, when it is determined that the size recognized by the apparatus is different from the actual size, image writing is forcibly stopped and the apparatus is stopped. Some are designed to stop (and jam).

  In addition, as a paper size detection method, a paper feed cassette or the like that contains paper is provided with a side fence that regulates the side of the paper, and an end fence that regulates the end. In general, the size of the paper in the width direction and the trailing edge of the paper are detected.

For example, Patent Document 1 describes that at least one recording sheet trailing edge detection sensor is provided between the registration sensor and the manual sheet feeding unit in the recording sheet conveyance path from the manual feed table.
Japanese Patent Laid-Open No. 06-161188

Japanese Patent Application Laid-Open No. 2004-228561 describes that a trailing edge detection unit for detecting the trailing edge of a recording sheet fed from a sheet feeding cassette in the apparatus main body is provided.
Japanese Patent No. 3416232

Japanese Patent Application Laid-Open No. 2004-228561 describes that a recording material trailing edge detection sensor is arranged on the registration roller inlet side in the apparatus main body.
Japanese Patent No. 3338166

Patent Document 4 discloses a sensor that detects the trailing edge of a sheet material being fed with respect to a sheet material fed from a second sheet feeding unit that feeds an indeterminate size sheet material of unknown size. It is described that it is provided.
Japanese Patent Laid-Open No. 08-314214

Japanese Patent Application Laid-Open No. H10-228561 describes that the trailing edge is detected by passing the trailing edge of the recording paper through the actuator of an optical registration sensor arranged in the apparatus main body.
JP 09-249338 A

Patent Document 6 describes that a document trailing edge detection sensor is disposed on a side fence.
Japanese Patent Laid-Open No. 10-218426

Patent Document 7 discloses a passage detection unit that detects a sheet fed to the transfer nip portion, and a sheet feeding of a sheet that is provided upstream of the transfer nip portion in the sheet feeding direction and fed to the transfer nip portion. A device is described in which any one of width detecting means for detecting a width in a direction orthogonal to the direction is used as a rear end detecting means.
JP 2002-055442 A

Patent Document 8 describes that a sheet material trailing edge detection means is disposed on an end fence.
JP 2004-026393 A

Patent Document 9 describes that a trailing edge detection sensor for detecting the trailing edge of a recording material having a different size is arranged only on the registration roller inlet side.
JP 2003-091113 A

  However, in the conventional image forming apparatus and sheet material feeding apparatus described above, a rear end regulating member (end fence) is provided like a manual sheet feeding unit and a sheet material accommodating unit capable of accommodating a plurality of sizes of sheet materials. If not, the rear end position cannot be detected according to the position of the rear end regulating member.

  For this reason, the rear end detection means is arranged near the registration roller in the apparatus main body. In such a configuration, manual feed means and sheets that can accommodate a plurality of sizes of sheet materials are used. There is a problem that the timing for detecting the trailing edge of the sheet material fed from the material accommodating means is delayed. As a result, there arises a problem that the apparatus often stops due to a setting mistake or a wrong set.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and an image forming apparatus and a sheet material that can detect the actual size of the sheet material at an earlier stage and can also handle sheet materials of different sizes. An object is to provide a feeding device.

  In order to solve the above-described problems, an image forming apparatus according to the present invention includes a manual sheet feeding unit that can store a plurality of sizes of sheet materials, and a rear end position of the sheet material fed from the manual sheet feeding unit. A rear end detection unit that is different from the front end position and detects within the manual sheet feeding unit, the rear end detection unit having a rotating member that can rotate in contact with the sheet material, The position of the rotating member is configured to be movable to at least two or more positions in the sheet material feeding direction.

  Here, at least the surface of the rotating member can be formed of a member having a high friction coefficient. The rotating member can be a spur. Further, the rotating member can be arranged at the center in the width direction of the manual sheet feeding unit and can be configured to be narrower than the width of the sheet material that can be stored. Further, it is preferable that a means for detecting the position of the rotating member in the sheet material feeding direction is provided. The rotating member is preferably movable between a position where it can contact the sheet material and a position where it is retracted from the sheet material accommodating portion of the manual sheet feeding means.

  Further, the rear end detecting means can be configured in an arm shape having a rotation fulcrum on the apparatus main body side. In this case, the rotating member can be configured as an endless belt member, and the rotating member can be configured as a spur or a roller member provided at the free end of the arm-shaped rear end detecting means. Moreover, it is preferable that the detection means which detects rotation of a rotation member is arrange | positioned at the apparatus main body side. Further, a scale is formed on the outer peripheral surface of the endless belt member, and a detecting means for detecting the scale can be arranged on the apparatus main body side. Moreover, it can be set as the structure provided with the structure which can move a rotation fulcrum to an up-down direction, and the position of a rotation fulcrum. In addition, the rear end detection unit can be configured to be stored between the manual sheet feeding unit and the apparatus main body when the manual sheet feeding unit is stored in the side surface of the apparatus main body. Further, the rotating member can be arranged at the center in the width direction of the manual sheet feeding unit and can be configured to be narrower than the width of the sheet material that can be stored.

  In the sheet material feeding device according to the present invention, the sheet material accommodating means capable of accommodating a plurality of sizes of sheet materials and the rear end position of the sheet material fed from the sheet material accommodating means are different from the front end position. A rear end detecting means for detecting within the sheet material accommodating means, the rear end detecting means having a rotating member that can rotate in contact with the sheet material, and the position of the rotating member It is configured to be movable to at least two different positions in the sheet material feeding direction.

  Here, the rear end detection means can be configured as an arm having a rotation fulcrum on the apparatus main body side.

  According to the image forming apparatus of the present invention, the trailing edge detection for detecting the trailing edge position of the sheet material fed from the manual feeding means in a position different from the leading edge position in the manual feeding means. The rear end detecting means has a rotating member that can rotate in contact with the sheet material, and the position of the rotating member can be moved to at least two different positions in the sheet material feeding direction. Since it is configured, it is possible to detect the trailing edge of the sheet material in the manual sheet feeding means, and it is possible to detect the actual size of the sheet material at an earlier stage, and it also supports sheet materials of different sizes. be able to.

  According to the sheet material feeding device of the present invention, after detecting the rear end position of the sheet material fed from the sheet material accommodation unit, which is different from the front end position, in the sheet material accommodation unit. The rear end detecting means includes a rotating member that can rotate in contact with the sheet material, and the position of the rotating member can be moved to at least two different positions in the sheet material feeding direction. Since it has a certain configuration, it is possible to detect the trailing edge of the sheet material in the sheet material accommodation means, so that the actual size of the sheet material can be detected at an earlier stage, and it is also possible to handle sheet materials of different sizes can do.

Embodiments of the present invention will be described below with reference to the accompanying drawings. First, an outline of an image forming apparatus according to the present invention including a sheet material feeding apparatus according to the present invention will be described with reference to FIG.
The image forming apparatus includes a main body standard tray 1 mounted in an apparatus main body that stores paper P that is a sheet material, and a sheet material storage unit that is mounted outside the apparatus main body that stores the paper P that is a sheet material. A manual paper feed tray 2 as manual paper feed means is provided.

  Then, the sheet material P accommodated in the main body standard tray 1 is separated one by one by the main body feeding roller 3 and the separation pad 4 and fed to the registration roller 11 or manually fed. The sheet material P accommodated in the sheet 2 is fed and conveyed by the manual sheet feeding roller 5 and the separation pad 6 one by one toward the separation resist roller 11.

  The sheet material P fed to the registration roller 11 is further conveyed to transfer a toner image formed on the image carrier 12 on which a toner image is formed by an electrophotographic method to and from the transfer roller 13. The paper is discharged to a paper discharge tray of the main body of the apparatus through a fixing device that does not.

  Here, in order to detect the size of the sheet material P, a leading edge detection position sensor (registration sensor) 14 for detecting the leading edge of the sheet material P is disposed on the upstream side of the registration roller 11, and on the main body standard tray 1 side. The rear end detection device 15 for detecting the rear end of the sheet material P is disposed, and further, the manual sheet feeding tray 2 side detects the rear end of the sheet material P outside the main body of the sheet material feeding according to the present invention. A rear end detection device 16 which is a rear end detection means in the apparatus is arranged.

  Then, the registration sensor 14 detects the leading edge position of the sheet material P, detects the trailing edge position of the sheet material P fed from the manual sheet feeding tray 2 based on the trailing edge detection device 16, and detects the leading edge detection position. The length L of the fed sheet material P is detected in consideration of the distance L to the rear end detection position.

  Therefore, the rear end detection device according to the first embodiment of the present invention will be described with reference to FIGS. 2 is a schematic explanatory diagram for explaining the first embodiment, FIG. 3 is a schematic explanatory diagram for explaining the operation of the first embodiment, and FIG. 4 is for explaining the first embodiment and a second embodiment to be described later. FIG.

  The trailing edge detection device 16 is disposed outside the frame 31 of the apparatus main body and in the manual paper feed tray 2. The rear end detection device 16 is in contact with the sheet material P on the frame 21 and rotatably holds a roller 22 as a rotating member that can be rotated as the sheet material P moves. A slit wheel 24 in which slits are formed substantially radially is attached to one end of 23. In addition, a rear end detection sensor 25 composed of a transmission type photosensor is disposed to detect the slit of the slit wheel 24.

  The frame 21 is mounted so as to be movable (slidable) in the direction indicated by an arrow M with respect to the manual paper feed tray 2 which is a sheet material placing table. The roller 22 is disposed at the center in the width direction of the sheet material P when the frame 21 is mounted on the manual sheet feed tray 2 (note that the sheet material P is fed by center positioning). The width of the roller 22 in the direction intersecting the feeding direction is narrower than the width of the smallest size sheet material that can be accommodated in the manual sheet feeding tray 2. The rollers 22 can move in the vertical direction with respect to the placement surface of the manual paper feed tray 2 according to the height of the sheet material P stored in the manual paper feed tray 2. That is, the roller 22 is held by the frame 10 in a state in which the roller 22 is in contact with the uppermost sheet material P by its own weight.

  The roller 22 has at least a surface formed of a member having a high friction coefficient, such as rubber. Thereby, when the sheet material P is being fed in a state where the roller 22 is in contact with the sheet material P, the roller 22 is reliably rotated (turned around), and when the rear end of the sheet material P is removed (passed). The roller 22 can stop immediately. In addition, it can replace with the roller 22 as a rotation member, and can also use a spur.

  On the other hand, an energization pattern 26 is provided inside the manual paper feed tray 2, and an energization terminal plate 27 that is in contact with the energization pattern 26 is provided on the frame 21 side of the trailing edge detection device 16. The position of the frame 21 slidable in the direction indicated by the arrow M can be detected by changing the energization terminal of the energization pattern 26 according to the position of the energization terminal plate 27 (or changing the resistance value). Thereby, the position (rear end detection position) of the roller 22 as the rotating member in the sheet material feeding direction can be detected.

  According to the rear end detection device 16 configured in this way, as shown in FIG. 2, a relatively long size sheet material P1 is placed and accommodated in the manual feed tray 2, and the accommodated sheet material P1 is accommodated in the accommodated sheet material P1. When the frame 21 is set at a position where the roller 22 as the rotating member contacts, the uppermost sheet material P1 is fed by the manual sheet feeding roller 5 and conveyed toward the registration roller 11 by the conveying roller 18. The roller 22 rotates while the sheet material P1 is being fed. The slit wheel 24 is rotated by the rotation of the roller 22, and the level changes from the rear end detection sensor 25 according to the presence or absence of the slit of the slit wheel 24 (the state transitions to “H”, “L”). A signal will be output.

  When the rear end of the fed sheet material P1 passes through the roller 22, the rotation of the roller 22 stops and the slit wheel 24 also stops rotating. Therefore, the signal output from the rear end detection sensor 25 is the stop time. Remain at the level (no state transitions).

  Therefore, by detecting that the output signal of the trailing edge detection sensor 25 does not change for a predetermined time after the start of feeding, the trailing edge of the sheet material P1 has passed the trailing edge detection position by the roller 22, that is, the sheet material. The rear end of P1 can be detected.

  Here, since the position of the roller 22 of the rear end detection device 16 can be detected by a signal obtained from the energization pattern 26 according to the position of the frame 21, the front end of the registration sensor 14 from the position of the roller 22 (rear end detection position). A distance L1 to the detection position can be obtained.

  In this case, if the position of the roller 22 of the rear end detection device 16 (rear end detection position) is fixed, the rear end is positioned upstream from the rear end detection position, meaning that the length in the feeding direction is shorter. The same applies hereinafter.) When the sheet material P having a size is accommodated, the trailing edge cannot be detected. On the other hand, when the roller 22 is brought closer to the position of the roller 22 so as to correspond to the short-sized sheet material P, the rear end of the sheet material P passes through the roller 22 when the long-sized sheet material P is accommodated. It takes time until the rear end detection becomes slow.

  Therefore, in this embodiment, the position of the roller 22 of the rear end detection device 16 can be moved to an arbitrary position (that is, linearly) by moving the frame 21. As a result, as shown in FIG. 3, when a relatively short sheet material P2 is accommodated, the frame 21 is moved toward the sheet feeding roller 5 so that the roller 22 is moved near the rear end of the sheet material P2. Keep in contact

  Thereby, the roller 22 rotates until the rear end of the sheet material P2 passes in the same manner as in the case of the sheet material P1 described above, and when the rear end of the sheet material P2 passes, the roller 22 stops and the rear end Since the position of the roller 22 (rear end detection position) at this time can be detected by a signal obtained from the energization pattern 26 in accordance with the position of the frame 21, the registration from the position of the roller 22 (rear end detection position) is possible. The distance L2 to the tip detection position by the sensor 14 can be obtained.

  As described above, the manual sheet feeding unit capable of accommodating a plurality of sizes of sheet materials and the rear end position of the sheet material fed from the manual sheet feeding unit are different from the leading end position. A trailing edge detecting means for detecting within the sheet feeding means, the trailing edge detecting means having a rotating member that can rotate in contact with the sheet material, and the position of the rotating member is at least in the sheet material feeding direction. Since it is configured to be able to move to two or more different positions, the trailing edge position of the sheet material can be detected in the manual feed tray, and the trailing edge is detected early after the sheet material is fed. Can be detected, and the rear end detection position can be moved, so that various sizes of sheet materials can be handled.

  Further, by configuring the detection unit with a rotating member that rotates in contact with the sheet material, it is possible to improve the accuracy of the trailing edge detection. In addition, since the rotating member has a configuration in which at least the surface is formed of a member having a high friction coefficient, idling of the rotating member serving as the detection unit is suppressed, and the rear end detection accuracy is improved. In addition, the rotating member is arranged in the center of the manual feed means in the width direction and is narrower than the sheet material that can be accommodated, so it interferes with the side fence even when feeding the smallest size sheet material. The rear end can be detected without the need to provide a plurality of detection units.

  Furthermore, by providing a means for detecting the position of the rotating member in the sheet material feeding direction, it is possible to detect the trailing edge detection position and to detect the trailing edge of various sizes of sheet material.

  A rear end detection apparatus according to a second embodiment of the present invention will be described with reference to FIGS. 5 to 7 and FIG. 4 described above. 5 is a schematic explanatory view for explaining the second embodiment, FIG. 6 is a schematic explanatory view for explaining the operation of the embodiment, and FIG. 7 is a schematic explanatory view for explaining the operation of the embodiment. It is.

  Here, one end of an arm 28 is swingably attached to the frame 21 of the rear end detection device 16, and the other end of the arm 28 is mounted on a frame 31 of the image forming apparatus main body so as to be movable up and down. The entire frame 21 including the roller 22 can be opened upward. That is, the roller 22 as the rotating member is configured to be movable between a position where it can contact the sheet material P and a position where it is retracted from the sheet material storage portion of the manual sheet feed tray 2.

  The operation of the rear end detection device 16 is the same as that of the first embodiment. At the same time, as shown in FIG. 7, the frame 21 of the trailing edge detection device 16 can be opened upward together with the roller 22 (the roller 22 is set to the retracted position). When the sheet is set, the trailing edge detection device 16 does not get in the way, and the sheet material setting property is improved.

A rear end detection apparatus according to a third embodiment of the present invention will be described with reference to FIG. FIG. 8 is an explanatory perspective view for explaining the third embodiment.
Here, a spur 32 is used instead of the roller 22 of each of the embodiments. By bringing the spur 32 into contact with the sheet material P, the spur 32 is rotated by feeding the sheet material P, so that the rear end of the sheet material P can be detected in the same manner as in the above embodiments. Moreover, by using the spur member of the detection unit as a spur, the cost can be relatively reduced as compared with the roller.

  A rear end detection apparatus according to a fourth embodiment of the present invention will be described with reference to FIGS. 9 is a schematic explanatory view for explaining the fourth embodiment, FIG. 10 is a schematic explanatory view for explaining the operation, and FIG. 11 is a perspective view for explaining the moving body and the mechanism housed in the arm. It is explanatory drawing.

  The rear end detection device 36 has an arm 41 which is an arm-shaped member having a pivot point with respect to the apparatus main body side, and a support shaft 43 rotatably held at a free end portion of the arm 41 as a rotation member. The roller 42 is fixedly provided so that the roller 42 is rotatably held with respect to the arm 41.

  The device body side of the arm 41 can be rotated by a support shaft 46 attached to a movable body 45 that is mounted on a support rail 44 provided on the frame 31 so as to be movable up and down (up and down). By supporting (swingable), the rotation fulcrum of the arm 41 can be moved in the vertical direction on the apparatus main body side. The support rail 44 is provided with restricting means (not shown) so that the moving body 45 can be stopped at an arbitrary height position (or stepwise height position) with respect to the frame 31. Further, in order to detect the height position of the moving body 45 (the height position of the rotation fulcrum), the energization pattern and the energization terminal plate as described in the above embodiments are provided.

  Then, as shown in FIG. 11, an endless belt 53 is stretched between a pulley 51 provided on the support shaft 43 of the roller 42 and a pulley 52 provided on the support shaft 46 serving as a rotation fulcrum of the arm 41. The support shaft 46 is configured to rotate by the rotation of the roller 42. Further, in the moving body 45, a slit wheel 54 is fixed to the support shaft 46, and a transmission type photosensor that detects the slit of the slit wheel 54 is used. The rear end detection sensor 55 is arranged. The arrangement position of the roller 42 is the center in the width direction of the sheet material, as in the above-described embodiments, and the width of the roller 42 (the width in the direction orthogonal to the old bidirectional direction) is larger than the width of the minimum-size sheet material. It is narrow.

  With this configuration, when the sheet material P stored in the manual sheet feed tray 2 is a sheet material P2 having a short size as shown in FIG. 9, the moving body 45 is moved upward to stop. When the roller 42 is brought into contact with the sheet material P2 at a position closer to the rear end on the downstream side in the feeding direction than the rear end of the sheet material P2, and the sheet material P1 has a long size as shown in FIG. 45 is moved downward to stop, and the roller 42 is brought into contact with the sheet material P1 at a position closer to the rear end on the downstream side in the feeding direction than the rear end of the sheet material P1.

  Then, by feeding the sheet material P from the manual sheet feeding tray 2, the roller 42 rotates, and the rotation of the roller 42 causes the slit wheel 54 to rotate via the belt 53. In response to the rotation of the slit wheel 54, a pulse-like signal whose state transitions to “H” and “L” is output, and the rotation of the roller 42 is stopped when the rear end of the sheet material P passes through the roller 42, and the slit Since the wheel 54 stops and the state transition of the signal output from the trailing edge detection sensor 55 is eliminated, the trailing edge of the sheet material P can be detected.

  In this way, by moving the position of the roller 42 with respect to the sheet materials P1 and P2 having different sizes, the rear end detection position can be adjusted to a position where the rear end of the sheet material can be detected early, Edge detection can be performed early.

  Further, in this rear end detection device 36, the arm 41 can be rotated with respect to the moving body 45 on the apparatus main body side, so that the sheet material P is set in the manual paper feed tray 2 as in the third embodiment. When doing so, the arm 41 can be rotated upward (to the position retracted from the roller 42 manual feed tray 2), and the sheet material setting property is improved.

  In this way, by configuring the trailing edge detection means in the shape of an arm having a rotation fulcrum on the apparatus main body side, the trailing edge detection means can be reduced in size, and the setability of the sheet material to the manual feed tray can be improved. I can plan.

  Further, by arranging the slit wheel and the rear end detection sensor inside the apparatus main body, it is not necessary to route the wiring to the rotating member side, and the rear end detection means can be downsized. In addition, by making the rotation fulcrum of the arm variable in the vertical direction, the detection unit can be moved in the sheet material feeding direction, and various sizes of sheet materials can be handled. Further, by providing means for detecting the rotation fulcrum position of the arm, the trailing edge detection position can be detected, and the trailing edge detection of various sizes of sheet materials can be performed.

  Also, by arranging the trailing edge detection means in the center of the sheet material and making the width of the detection part smaller than the width of the sheet material to be fed, it also interferes with the side fence when feeding the minimum size sheet material In addition, the trailing edge of the sheet material can be detected without providing a plurality of detection units.

A rear end detection apparatus according to a fifth embodiment of the present invention will be described with reference to FIG. FIG. 12 is an explanatory perspective view similar to FIG. 11 for explaining the fifth embodiment.
Here, a spur 57 is used instead of the roller 42 of each of the embodiments. By bringing the spur 57 into contact with the sheet material P, the spur 57 is rotated by feeding the sheet material P, so that the rear end of the sheet material P can be detected in the same manner as in each of the above embodiments. Moreover, by using the spur member of the detection unit as a spur, the cost can be relatively reduced as compared with the roller.

A rear end detection apparatus according to a sixth embodiment of the present invention will be described with reference to FIG. FIG. 13 is an explanatory perspective view similar to FIG. 11 for explaining the sixth embodiment.
Here, the pulley 61 is rotatably held by the support shaft 58 on the free end side of the arm 41 of the fourth embodiment, and the support shaft 59 of the pulley 62 is rotatably held on the movable body 45 side. Between the pulley 61 and the pulley 62, an endless belt 63 is wound as a rotating member that can rotate (circulate and move) in contact with the sheet material P. The surface of the endless belt 63 (the surface in contact with the sheet material P) is formed of a high friction coefficient member. In addition, the slit wheel 54 is attached to the shaft of the pulley 62, and the rear end detection sensor 55 for detecting the slit of the slit wheel 54 is disposed as in the above embodiment. A part of the arm 41 on the free end side is opened to bring the endless belt 63 into contact with the sheet material P.

  In this way, by using an endless belt as the rotation member of the rear end detection means (device) configured in the arm shape, drive transmission to the rear end detection sensor unit and common use of the rear end detection unit (rotation member) can be achieved. Thus, the number of parts can be reduced, and the idling of the detection unit can be suppressed to improve the accuracy of the rear end detection.

A rear end detection apparatus according to a seventh embodiment of the present invention will be described with reference to FIG. FIG. 14 is a perspective explanatory view similar to FIG. 11 for explaining the seventh embodiment.
Here, the reflective scale 64 is formed on the front surface (or the back surface side) of the endless belt 53 of the fourth embodiment, and the reflective scale 64 of the endless belt 53 is a rear end made of a reflective photosensor. Detection is performed by the detection sensor 65.

  Since the scale is provided on the endless belt and the sensor for detecting the scale on the belt is arranged inside the main body of the machine, the slit wheel is unnecessary, and the wiring to the rear end detector is not required. Thus, the rear end detection means can be reduced in size. In this case, if the scale is formed on the back side of the endless belt, the scale can be prevented from being soiled.

A rear end detection apparatus according to an eighth embodiment of the present invention will be described with reference to FIG. FIG. 15 is a schematic explanatory diagram for explaining the eighth embodiment.
Here, a link mechanism 72 is disposed between the moving body 45 of the rear end detection device 36 and the groove 71 provided in the manual paper feed tray 2. The link mechanism 72 has a link 73 with one end rotatably attached to the moving body 45, one end rotatably attached to the other end of the link 73, and the other end of the manual feed tray 2. A link 74 is slidably engaged with the groove 71.

  Thus, when the manual feed tray 2 is rotated in the direction of arrow C and stored in the apparatus main body, the other end portion of the link 74 of the link mechanism 72 is placed on the manual feed tray 2 along the groove 71 on the rear end side. Along with this, the moving body 45 descends, the free end side (rotating member side) of the arm 41 moves downstream in the feeding direction, and the arm 41 rotates in the same direction as the manual feed tray 2. The trailing edge detection device 36 is moved and stored in the manual feed tray 2.

  In this way, by restricting the movable position of the pivotal fulcrum of the arm of the trailing edge detection device, the trailing edge of the trailing edge detection device arm and the manual feeding tray are not stretched when the manual feeding tray is stored. The detection apparatus can be stored in the apparatus main body at the same time as the manual sheet feeding tray.

A rear end detection apparatus according to a ninth embodiment of the present invention will be described with reference to FIG. FIG. 16 is a schematic explanatory diagram for explaining the ninth embodiment.
Here, the movable body 45 of the rear end detection device 36 is configured to stop at two positions of the lowermost position and the uppermost position, and the manual feed tray 2 is indicated by an arrow C in a state where the movable body 45 is at the lowermost position. When it is rotated in the direction and stored in the apparatus main body, the arm 41 is also rotated in the same direction as the manual feed tray 2 as indicated by the arrow, and the trailing edge detection device 36 is stored inside the manual feed tray 2. I am doing so. In other words, the trailing edge detection device 36, which is a trailing edge detection means, is stored between the manual feeding tray 2 and the frame 31 of the apparatus body when the manual feeding tray 2 is stored on the side surface of the frame 31 of the apparatus body. It is assumed to be configured.

  In this way, by restricting the movable position of the pivotal fulcrum of the arm of the trailing edge detection device, the trailing edge of the trailing edge detection device arm and the manual feeding tray are not stretched when the manual feeding tray is stored. The detection device can be housed in the main unit at the same time as the manual feed tray, and the position of the rotation fulcrum is restricted only at the uppermost and lowermost positions. This eliminates the need for detection of the cost and can reduce costs. That is, the rear end detection means is configured to be stored between the manual paper feed tray and the apparatus main body when the manual paper feed tray is stored in the side surface of the apparatus main body.

Next, a part related to manual sheet feeding control in this image forming apparatus will be described with reference to a block diagram of FIG.
The main control unit 101 controls the entire image forming apparatus and includes a microcomputer. The main control unit 101 drives the sheet feeding motor 103 via the motor driver 102 and operates a manual sheet feeding clutch (not shown) to transmit the driving force of the sheet feeding motor 103 to the manual sheet feeding roller 5. The manual feed roller 5 is rotated to feed the sheet material P placed and stored in the manual feed tray 2 one by one.

  The main control unit 101 receives the output signal of the registration sensor 14 and detects the leading end position of the fed sheet material P. Further, the output signal of the trailing edge detection sensor 25 in the first embodiment is input, and the trailing edge position of the sheet material P fed from the manual sheet feeding tray 2 is detected as described above. Further, the rear end detection position information from the rear end detection position detection circuit 104 that detects the rear end detection position based on the output of the energization pattern 26 is input, and the distance L from the rear end detection position to the registration sensor 14 is detected. .

  The main control unit 101 controls the writing control unit 106 to control image writing on the image carrier 12. The main control unit 101 is connected to an operation panel 106 for inputting paper size information and displaying required information. Further, the main control unit 101 is connected to a network via the communication circuit 109 and inputs information provided from various information processing apparatuses 110 such as personal computers and outputs information to the information processing apparatus 110. It should be noted that each part is not shown in order to execute an electrophotographic process such as charging, development, and transfer.

Thus, an example of processing when an image is formed by manually feeding paper will be described with reference to FIG.
When the sheet material P is fed from the manual feed tray 2, the paper feed motor 103 is driven to turn on a manual feed clutch (not shown), and the manual feed roller 5 is driven to rotate to the manual feed tray 2. One sheet material P accommodated is separated and fed.

  Then, based on the detection signal from the rear end detection position detection circuit 104, the rear end detection position information by the rear end detection device 16 is captured. After that, it is determined whether or not the state transition of the output signal of the trailing edge detection sensor 25 has disappeared and the trailing edge position of the fed sheet material P has been detected. Here, when the trailing edge position of the fed sheet material P is detected, it is determined whether or not the registration sensor 14 has detected the leading edge position of the fed sheet material P, and the leading edge position of the sheet material P is determined. Is detected (calculated), based on the distance L from the leading edge detection position to the trailing edge detection position, the feeding time, and the like, the size of the sheet material P (the length in the feeding direction).

  Thereafter, it is determined whether or not the size (actual size) of the fed sheet material P matches the sheet material size set by the operation panel 108 or the information processing apparatus 110 on the host side. If so, the next processing is continued.

  On the other hand, when the actual size of the fed sheet material P does not match the set sheet material size, information indicating that the sizes do not match is displayed on the operation panel 108 or the information processing apparatus 110. Then, after recalculating the writing timing of the writing unit 106 according to the actual size, the processing is continued.

  In this way, the trailing edge of the sheet material fed from the manual sheet feed tray can be detected at an early stage, so that the apparatus can be forcibly stopped due to a size error or out of the sheet material area (feeding). It is possible to prevent writing for image formation (outside the area in the direction).

  In each of the above-described embodiments, the present invention is described as an example in which the present invention is applied to a manual feeding device of an image forming apparatus that forms an image by an electrophotographic method, but other image forming apparatuses or sheet material supply thereof are also described. The present invention can also be applied to a feeding apparatus, and is widely applied to an image forming apparatus including a copying machine, a facsimile machine, a printing machine, or a multifunction machine, an image forming apparatus that forms an image by an inkjet recording method, or a sheet material feeding apparatus thereof. can do.

  Therefore, an example of an image forming apparatus that forms an image by a liquid ejection method as an example of the image forming apparatus according to the present invention will be described with reference to FIGS. FIG. 19 is a schematic configuration diagram illustrating the overall configuration of the image forming apparatus, and FIG. 20 is a plan view illustrating an image forming unit and a sub-scanning conveyance unit of the apparatus.

  The image forming apparatus includes an image forming unit (means) 202 for forming an image, a sub-scanning conveying unit (means) 203, and the like inside the apparatus main body 201 (inside the casing). A recording medium (hereinafter referred to as “paper”, but the material is not limited to paper) 205, which is a transported member, is separated and fed one by one from a paper feeding unit (means) 204 that is a provided storage means. The image forming unit 202 ejects liquid droplets onto the sheet 205 to form (record) the sheet 205 while intermittently conveying the sheet 205 at a position facing the image forming unit 202 by the sub-scanning conveying unit 203. After that, the paper 205 is discharged onto a paper discharge tray 207 formed on the upper surface of the apparatus main body 201 through the paper discharge transport unit 206. The image forming unit 202 and the sub-scanning conveyance unit 203 are unitized to form an engine unit 300, which is detachably attached to the apparatus main body 201.

  The image forming apparatus also has an image reading unit (scanner) for reading an image above the discharge tray 207 above the apparatus main body 201 as an input system for image data (print data) formed by the image forming unit 202. Part) 211. In this image reading unit 211, an image of a document placed on the contact glass 212 is moved by a scanning optical system 215 including an illumination light source 213 and a mirror 214 and a scanning optical system 218 including mirrors 216 and 217 moving. The scanned document image is read as an image signal by the image reading element 220 disposed behind the lens 219, and the read image signal is digitized and subjected to image processing, and the image-processed print data is printed. be able to. Note that a pressure plate 210 is provided on the contact glass 212 for pressing the document.

  Here, as shown in FIG. 20, the image forming unit 202 of the image forming apparatus is provided on a carriage guide (guide rod) 221 and a rear stay 301B which are horizontally mounted between the front side plate 3101F and the rear side plate 301R. A guide stay (not shown) holds the carriage 223 so as to be movable in the main scanning direction, and the main scanning motor 227 moves and scans in the main scanning direction via a timing belt 229 spanned between the driving pulley 228A and the driven pulley 228B.

  On the carriage 223, recording heads 224k1 and 224k2 each composed of two droplet ejection heads that eject black (K) ink, cyan (C) ink, magenta (M) ink, and yellow (Y) Recording heads 224c, 224m, and 224y each composed of a single droplet discharging head for discharging ink (totally referred to as “recording head 224” when colors are not distinguished and collectively referred to as “recording head 224”) are included. A shuttle type is mounted, in which the carriage 223 is moved in the main scanning direction, and droplets are ejected from the recording head 224 while the sheet 5 is fed in the sheet conveying direction (sub-scanning direction) by the sub-scanning conveying unit 3. Yes.

  A sub tank 225 is mounted on the carriage 223 in order to supply a recording liquid of a required color to each recording head 224. On the other hand, as shown in FIG. 19, a recording liquid containing black (K) ink, cyan (C) ink, magenta (M) ink, and yellow (Y) ink from the front of the apparatus main body 201 to the cartridge mounting portion 226A. Each color ink cartridge 226 can be detachably mounted, and ink (recording liquid) is supplied from each color ink cartridge 226 to each color sub-tank 225 via a tube (not shown). Note that black ink is supplied from one ink cartridge 226 to two sub tanks 225.

  Note that the recording head 224 uses a piezoelectric element as a pressure generating means (actuator means) for pressurizing ink in the ink flow path (pressure generation chamber) and deforms a vibration plate that forms the wall surface of the ink flow path. A so-called piezo type that discharges ink droplets by changing the volume in the flow channel, or discharges ink droplets with a pressure generated by heating the ink in the ink flow channel using a heating resistor to generate bubbles. The so-called thermal type, the diaphragm that forms the wall surface of the ink flow path and the electrode are placed opposite to each other, and the diaphragm is deformed by the electrostatic force generated between the vibration plate and the electrode, thereby the ink flow path inner volume It is possible to use an electrostatic type or the like that discharges ink droplets by changing the above.

  Also, as shown in FIG. 20, a linear scale 328 having slits is provided between the front plate 301F and the rear plate 301R along the main scanning direction of the carriage 223, and the linear scale 328 is provided on the carriage 223. An encoder sensor 329 made up of a transmission type photosensor for detecting the slit is provided, and the linear scale 328 and the encoder sensor 329 constitute a linear encoder that detects the movement of the carriage 223.

  Further, as shown in FIG. 20, a maintenance / recovery mechanism (device) 321 for maintaining and recovering the nozzle state of the recording head 224 is disposed in the non-printing area on one side of the carriage 223 in the scanning direction. . This maintenance / recovery mechanism 321 is a cap member for capping each nozzle surface of the five recording heads 224, one suction cap 322a that also serves as a moisturizing agent, four moisturizing caps 322b to 322e, A wiper blade 324, which is a wiping member for wiping the nozzle surface of the recording head 224, and an idle ejection receiver 325 for performing idle ejection are arranged.

  Further, an idle ejection receiver 326 for performing idle ejection is disposed in the non-printing area on the other side of the carriage 223 in the scanning direction. Openings 327 a to 327 e are formed in the idle discharge receiver 326.

  The sub-scanning conveyance unit 203 is a conveyance roller 232 that is a driving roller and a tension roller for conveying the paper 5 fed from below to the image forming unit 202 while changing the conveyance direction by approximately 90 degrees. An endless transport belt 231 that is bridged between the driven rollers 233, a charging roller 234 that is a charging unit to which an AC bias voltage that is an alternating voltage is applied to charge the surface of the transport belt 231, and a transport belt 231 The image is formed by the guide member 235 that guides the sheet 205 in the opposite region of the image forming unit 202, a pressing roller (pressure roller) 236 that presses the paper 205 against the conveying belt 231 at a position facing the conveying roller 232, and the image forming unit 202. Separating claws 237 for separating the formed paper 205 from the conveyor belt 231 and discharging the separated paper 205 And a conveying roller 238 for feeding the feed portion 206.

  The transport belt 231 of the sub-scan transport section 203 is rotated in the paper transport direction (sub-scan direction) in FIG. 20 by rotating the transport roller 232 from the sub-scan motor 331 via the timing belt 332 and the timing roller 333. It is configured to do.

  The paper feeding unit 204 can be inserted into and removed from the apparatus main body 201 and separates the paper feeding cassette 241 serving as a storage unit for stacking and storing a large number of papers 205 and the paper 205 in the paper feeding cassette 241 one by one. A sheet feeding roller 242 and a friction pad 243 for feeding out, and a registration roller pair 44 for conveying the fed sheet 5 to the sub-scanning conveying unit 3 are provided. The sheet feeding roller 242 is rotated by a sheet feeding motor (drive source) 245 including an HB type stepping motor via a sheet feeding clutch (not shown), and the registration roller pair 244 is also rotated by the sheet feeding motor 245.

  The sheet feeding unit 204 also includes a manual sheet feeding tray 246 for stacking and storing sheets 205 and a manual sheet feeding roller for feeding sheets 205 as a sheet material one by one from the manual sheet feeding tray 246. 247, a conveyance roller 248 for conveying the sheet 205 fed from the manual sheet feeding roller 247, and a sheet 205 fed from an optional sheet feeding cassette or duplex unit under the apparatus main body 201. A conveyance roller 249 for conveying is provided.

  The paper discharge transport unit 206 includes a pair of paper discharge transport rollers 261 and 262 that transport the paper 205 on which image formation has been performed, and a pair of paper discharge transport rollers 263 and a paper discharge roller 264 for sending the paper 205 to the paper discharge tray 207. And.

  In the image forming apparatus configured as described above, the rotation amount of the conveyance roller 232 that drives the conveyance belt 231 is detected, and the sub-scanning motor 331 is driven and controlled according to the detected rotation amount, and an AC (not shown) is also illustrated. A positive and negative rectangular wave high voltage, which is an alternating voltage, is applied from the bias supply unit to the charging roller 234, whereby positive and negative charges are alternately band-shaped in the conveying direction of the conveying belt 231. Is applied to the conveyor belt 231 with a predetermined charging width, and an unequal electric field is generated.

  Therefore, the conveyance belt in which an unequal electric field is generated by the sheet 205 being fed from the sheet feeding unit 204 and fed between the conveyance roller 232 and the presser roller 236 to form positive and negative charges. When the paper 5 is fed onto the paper 231, the paper 5 is instantly polarized according to the direction of the electric field, and is attracted onto the transport belt 231 by the electrostatic attraction force, and is transported as the transport belt 231 moves.

  Then, while the paper 105 is intermittently transported by the transport belt 231, a recording liquid droplet is ejected from the recording head 224 onto the paper 205 to record (print) an image, and the front end of the paper 205 on which printing is performed. The side is separated from the conveyance belt 231 by the separation claw 237 and sent to the paper discharge conveyance unit 206 by the conveyance roller 238.

  Further, during printing (recording) standby, the carriage 223 is moved to the maintenance / recovery mechanism 321 side, and the nozzle surface of the recording head 234 is capped by the cap 322 so that the nozzles are kept in a wet state. To prevent. In addition, the recording liquid is sucked from the nozzle (referred to as “nozzle suction” or “head suction”) while the recording head 234 is capped with the suction and moisture retention cap 322a, and the recovered recording liquid and bubbles are discharged. Wiping is performed by the wiper blade 124 in order to clean and remove ink adhering to the nozzle surface of the recording head 234 by this recovery operation. In addition, a blank ejection operation is performed in which ink that is not related to printing is ejected toward the blank ejection receiver 325 before recording is started or during recording. Thereby, the stable ejection performance of the recording head 234 is maintained.

  Next, by providing the manual paper feed tray 246 in this image forming apparatus with the trailing edge detection means of the present invention, the rear edge of the paper fed from the manual paper feed tray can be detected at an early stage, and the rear Since the edge detection position can be moved, the trailing edge detection position can be detected at an early stage even for a plurality of sizes of paper.

FIG. 2 is a schematic explanatory view illustrating an outline of an example of an image forming apparatus according to the present invention including a sheet material feeding device according to the present invention. It is typical explanatory drawing with which it uses for description of 1st Embodiment of this invention. It is typical explanatory drawing with which it uses for operation | movement description of the same embodiment. It is an isometric view explanatory drawing used for description of the same embodiment and 2nd Embodiment mentioned later. It is typical explanatory drawing with which it uses for description of 2nd Embodiment of this invention. It is typical explanatory drawing with which it uses for operation | movement description of the same embodiment. It is typical explanatory drawing with which it uses for operation | movement description of the same embodiment. It is perspective explanatory drawing with which it uses for description of 3rd Embodiment of this invention. It is typical explanatory drawing with which it uses for description of 4th Embodiment of this invention. It is typical explanatory drawing with which it uses for operation | movement description of the same embodiment. It is an isometric view explanatory drawing used for description of the rear-end detection apparatus of the embodiment. It is an isometric view explanatory drawing used for description of the rear-end | tip detection apparatus of 5th Embodiment of this invention. It is an isometric view explanatory drawing used for description of the rear-end | tip detection apparatus of 6th Embodiment of this invention. It is an isometric view explanatory drawing used for description of the rear-end | tip detection apparatus of 7th Embodiment of this invention. It is typical explanatory drawing with which it uses for description of 8th Embodiment of this invention. It is typical explanatory drawing with which it uses for description of 9th Embodiment of this invention. FIG. 4 is a block explanatory diagram of a control portion related to manual paper feed control in the image forming apparatus. FIG. 10 is a flowchart illustrating an example of manual paper feed control processing. FIG. 6 is an overall configuration diagram for explaining another example of an image forming apparatus according to the present invention. FIG. 6 is an explanatory plan view of the image forming unit and the sub-scanning conveyance unit.

Explanation of symbols

2. Manual feed tray (manual feed means, sheet material storage means)
DESCRIPTION OF SYMBOLS 5 ... Manual feed roller 11 ... Registration roller 16 ... Rear end detection device 22 ... Roller 24 ... Slit wheel 25 ... Rear end detection sensor 26 ... Current supply pattern 27 ... Current supply terminal plate 32 ... Spur 36 ... Rear end detection device 41 ... Arm 42 ... roller 44 ... support rail 45 ... moving body 53 ... endless belt 54 ... slit wheel 55 ... rear end detection sensor

Claims (17)

Manual sheet feeding means capable of accommodating sheets of a plurality of sizes;
A rear end position of the sheet material fed from the manual paper feed unit is a position different from the front end position and is detected in the manual paper feed unit.
The trailing edge detecting means has a rotating member that can rotate in contact with the sheet material, and the position of the rotating member can be moved to at least two different positions in the sheet material feeding direction. Image forming apparatus.   The image forming apparatus according to claim 1, wherein at least a surface of the rotating member is formed of a member having a high friction coefficient.   2. The image forming apparatus according to claim 1, wherein the rotating member is a spur.   4. The image forming apparatus according to claim 1, wherein the rotating member is disposed at a central portion in a width direction of the manual sheet feeding unit and is narrower than a sheet material that can be accommodated. 5. Image forming apparatus.   5. The image forming apparatus according to claim 1, further comprising means for detecting a position of the rotating member in a sheet material feeding direction.   6. The image forming apparatus according to claim 1, wherein the rotating member is movable between a position where the rotating member can contact the sheet material and a position where the rotating member is retracted from the sheet material accommodating portion of the manual sheet feeding unit. An image forming apparatus.   2. The image forming apparatus according to claim 1, wherein the rear end detecting means is an arm-shaped member having a rotation fulcrum on the apparatus main body side.   8. The image forming apparatus according to claim 7, wherein the rotating member is an endless belt member.   8. The image forming apparatus according to claim 7, wherein the rotating member is a spur or a roller member provided at a free end portion of an arm-shaped member.   8. The image forming apparatus according to claim 7, wherein a detecting unit that detects the rotation of the rotating member is disposed on the apparatus main body side.   9. The image forming apparatus according to claim 8, wherein a scale is formed on an outer peripheral surface of the endless belt member, and a detecting means for detecting the scale is disposed on the apparatus main body side. .   12. The image forming apparatus according to claim 7, wherein the rotation fulcrum is movable in the vertical direction.   13. The image forming apparatus according to claim 12, further comprising means for detecting the position of the rotation fulcrum.   14. The image forming apparatus according to claim 7, wherein the trailing edge detecting unit is disposed between the manual sheet feeding unit and the apparatus main body when the manual sheet feeding unit is stored in a side surface of the apparatus main body. The image forming apparatus is housed in an image forming apparatus.   15. The image forming apparatus according to claim 7, wherein the rotating member is disposed at a central portion in the width direction of the manual sheet feeding unit and is narrower than a sheet material that can be accommodated. Image forming apparatus. Sheet material accommodating means capable of accommodating a plurality of sizes of sheet materials;
The rear end position of the sheet material fed from the sheet material storage means is a position different from the front end position, and includes a rear end detection means for detecting within the sheet material storage means,
The trailing edge detecting means has a rotating member that can rotate in contact with the sheet material, and the position of the rotating member can be moved to at least two different positions in the sheet material feeding direction. Sheet material feeding device. 17. The image forming apparatus according to claim 16, wherein the trailing edge detecting means is an arm-shaped member having a rotation fulcrum on the apparatus main body side.

Images