US20190168978A1 - Rotary member support structure, transport device, charging device, and image forming apparatus - Google Patents
Rotary member support structure, transport device, charging device, and image forming apparatus Download PDFInfo
- Publication number
- US20190168978A1 US20190168978A1 US16/109,792 US201816109792A US2019168978A1 US 20190168978 A1 US20190168978 A1 US 20190168978A1 US 201816109792 A US201816109792 A US 201816109792A US 2019168978 A1 US2019168978 A1 US 2019168978A1
- Authority
- US
- United States
- Prior art keywords
- bearing
- support structure
- rotary member
- driven roller
- protrusion
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H29/00—Delivering or advancing articles from machines; Advancing articles to or into piles
- B65H29/12—Delivering or advancing articles from machines; Advancing articles to or into piles by means of the nip between two, or between two sets of, moving tapes or bands or rollers
- B65H29/125—Delivering or advancing articles from machines; Advancing articles to or into piles by means of the nip between two, or between two sets of, moving tapes or bands or rollers between two sets of rollers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H5/00—Feeding articles separated from piles; Feeding articles to machines
- B65H5/06—Feeding articles separated from piles; Feeding articles to machines by rollers or balls, e.g. between rollers
- B65H5/062—Feeding articles separated from piles; Feeding articles to machines by rollers or balls, e.g. between rollers between rollers or balls
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H29/00—Delivering or advancing articles from machines; Advancing articles to or into piles
- B65H29/12—Delivering or advancing articles from machines; Advancing articles to or into piles by means of the nip between two, or between two sets of, moving tapes or bands or rollers
- B65H29/14—Delivering or advancing articles from machines; Advancing articles to or into piles by means of the nip between two, or between two sets of, moving tapes or bands or rollers and introducing into a pile
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G15/00—Apparatus for electrographic processes using a charge pattern
- G03G15/02—Apparatus for electrographic processes using a charge pattern for laying down a uniform charge, e.g. for sensitising; Corona discharge devices
- G03G15/0208—Apparatus for electrographic processes using a charge pattern for laying down a uniform charge, e.g. for sensitising; Corona discharge devices by contact, friction or induction, e.g. liquid charging apparatus
- G03G15/0216—Apparatus for electrographic processes using a charge pattern for laying down a uniform charge, e.g. for sensitising; Corona discharge devices by contact, friction or induction, e.g. liquid charging apparatus by bringing a charging member into contact with the member to be charged, e.g. roller, brush chargers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H2404/00—Parts for transporting or guiding the handled material
- B65H2404/10—Rollers
- B65H2404/14—Roller pairs
- B65H2404/144—Roller pairs with relative movement of the rollers to / from each other
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H2404/00—Parts for transporting or guiding the handled material
- B65H2404/10—Rollers
- B65H2404/17—Details of bearings
- B65H2404/174—Details of bearings free bearing but slots or liquid support
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H2404/00—Parts for transporting or guiding the handled material
- B65H2404/60—Other elements in face contact with handled material
- B65H2404/61—Longitudinally-extending strips, tubes, plates, or wires
- B65H2404/611—Longitudinally-extending strips, tubes, plates, or wires arranged to form a channel
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H2801/00—Application field
- B65H2801/03—Image reproduction devices
- B65H2801/06—Office-type machines, e.g. photocopiers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H2801/00—Application field
- B65H2801/03—Image reproduction devices
- B65H2801/12—Single-function printing machines, typically table-top machines
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G21/00—Arrangements not provided for by groups G03G13/00 - G03G19/00, e.g. cleaning, elimination of residual charge
- G03G21/16—Mechanical means for facilitating the maintenance of the apparatus, e.g. modular arrangements
- G03G21/1642—Mechanical means for facilitating the maintenance of the apparatus, e.g. modular arrangements for connecting the different parts of the apparatus
- G03G21/1647—Mechanical connection means
Definitions
- the present invention relates to a rotary member support structure, to a transport device, to a charging device, and to an image forming apparatus.
- a rotary member support structure including: a rotary member including a shaft; a bearing that rotatably supports the shaft of the rotary member; a pressing member that presses the bearing in one direction; and a support that supports the bearing such that the bearing is movable in a pressing direction of the pressing member.
- FIG. 1 is a schematic diagram showing the structure of an image forming apparatus
- FIG. 2 is an enlarged schematic diagram showing an output transport path near a fixing device in the image forming apparatus in FIG. 1 ;
- FIG. 3 is a partial schematic cross sectional view showing the structure of a pair of first output rollers in the output transport path in FIG. 2 (the structure includes support structures);
- FIG. 4A is a schematic diagram showing a support structure for a driven roller in the pair of output rollers in FIG. 3 in exemplary embodiment 1;
- FIG. 4B is a schematic cross-sectional view taken along line IVB-IVB in FIG. 4A ;
- FIG. 5A is an enlarged schematic diagram showing the support structure for the driven roller in FIG. 4A ;
- FIG. 5B is a schematic diagram showing a contact state of a protrusion in the support structure in FIG. 5A ;
- FIG. 6A is a schematic diagram showing a state when the driven roller in the support structure in FIG. 5A is not rotating;
- FIG. 6B is a schematic diagram showing a state during rotation of the driven roller in the support structure in FIG. 6A ;
- FIG. 7A is an exploded perspective view showing the structure of a pressing member including the protrusion in the support structure in FIG. 5A ;
- FIG. 7B is a schematic cross-sectional view showing the pressing member in FIG. 7A ;
- FIG. 8A is an enlarged schematic diagram showing a support structure for the driven roller in exemplary embodiment 2;
- FIG. 8B is a schematic diagram showing a contact state of a protrusion in the support structure
- FIG. 9A is a schematic diagram showing a state when the driven roller in the support structure in FIG. 8A is not rotating;
- FIG. 9B is a schematic diagram showing a state during rotation of the driven roller in the support structure in FIG. 9A ;
- FIG. 10A is a schematic perspective view showing the structure of the protrusion in the support structure in FIG. 8A ;
- FIG. 10B is a schematic perspective view showing another example of the structure of the protrusion in the support structure.
- FIG. 11A is an enlarged schematic diagram showing a support structure for the driven roller in exemplary embodiment 3;
- FIG. 11B is a schematic diagram showing a contact state of a protrusion in the support structure
- FIG. 12A is a schematic diagram showing a state when the driven roller in the support structure in FIG. 11A is not rotating;
- FIG. 12B is a schematic diagram showing a state during rotation of the driven roller in the support structure in FIG. 12A ;
- FIG. 13 is an enlarged schematic diagram showing a support structure for a charging roller in exemplary embodiment 4.
- FIG. 14A is a schematic diagram showing a state when the charging roller in the support structure in FIG. 13 is not rotating;
- FIG. 14B is a schematic diagram showing a state during rotation of the charging roller in the support structure in FIG. 14A ;
- FIG. 15A is an enlarged schematic diagram showing a comparative support structure for the driven roller
- FIG. 15B is a schematic diagram showing a contact state between a pressing member and a bearing in the support structure
- FIG. 16A is a schematic diagram showing a state when the driven roller in the support structure in FIG. 15A is not rotating.
- FIG. 16B is a schematic diagram showing a state during rotation of the driven roller in the support structure in FIG. 16A .
- FIGS. 1 and 2 show exemplary embodiment 1 of the invention.
- FIG. 1 shows the structure of an image forming apparatus 1 according to exemplary embodiment 1.
- FIG. 2 is an enlarged illustration of an output transport path in the image forming apparatus 1 in FIG. 1 .
- an image based on the information about an image including letters, photographs, diagrams, etc. is formed using a developer on a recording paper sheet 9 that is an example of a transportation object or a recording medium.
- the image forming apparatus 1 includes: a housing 10 serving as an apparatus body; an image forming unit 2 that forms a toner image using a toner serving as the developer by, for example, electrophotography and transfers the toner image onto a recording paper sheet 9 ; a paper feeder 3 that holds a prescribed number of recording paper sheets 9 and feeds a recording paper sheet 9 to a transfer position of the image forming unit 2 ; and a fixing device 4 that fixes the toner image transferred onto the recording paper sheet 9 .
- the image forming unit 2 , the paper feeder 3 , and the fixing device 4 are disposed inside the housing 10 .
- the housing 10 is composed of various members such as structural members and exterior materials.
- An output tray 11 for placing ejected recording paper sheets 9 with images formed thereon is provided in an upper portion of the housing 10 .
- the output tray 11 is formed as a collecting surface having an inclined surface disposed below a paper outlet 12 of the housing 10 and is configured to collect recording paper sheets 9 ejected from the paper outlet 12 .
- the image forming unit 2 includes a photoreceptor drum 21 that is a driving drum and rotates in a direction indicated by arrow A and further includes a charging device 22 , an exposure device 23 , a developing device 24 , a transfer device 25 , and a cleaning device 26 that are disposed in this order around the photoreceptor drum 21 .
- the charging device 22 is, for example, a contact charging device that electrically charges the circumferential surface (the outer circumferential surface serving as an image-forming region) of the photoreceptor drum 21 to a prescribed potential with a prescribed polarity.
- the exposure device 23 irradiates the circumferential surface of the charged photoreceptor drum 21 with light (indicated by a chain double-dashed arrow) in response to image information (signals) inputted in various forms to the image forming apparatus 1 to thereby form an electrostatic latent image.
- the developing device 24 supplies a charged toner used as a developer to develop the electrostatic latent image on the photoreceptor drum 21 , and a toner image is thereby formed.
- the transfer device 25 is, for example, a contact transfer device that electrostatically transfers the toner image on the photoreceptor drum 21 onto a recording paper sheet 9 .
- the cleaning device 26 cleans the photoreceptor drum 21 by removing undesired substances such as the toner remaining on the circumferential surface of the photoreceptor drum 21 .
- the paper feeder 3 includes: a paper tray 31 that holds plural recording paper sheets 9 having a prescribed size and a prescribed type and used for image formation, the recording paper sheets 9 being stacked on a sheet stacking plate 32 ; and a delivery unit 33 that delivers the recording paper sheets 9 held in the paper tray 31 one by one.
- the paper tray 31 is attached to the housing 10 such that the paper tray 31 can be pulled out of the housing 10 , and plural paper trays 31 may be provided depending on use conditions.
- the recording paper sheets 9 used are, for example, recording mediums cut into a prescribed size such as plain paper sheets, coated paper sheets, or thick paper sheets.
- the fixing device 4 includes a housing 40 having an inlet for a recording paper sheet 9 and a paper outlet and further includes a heating rotary body 41 and a pressurizing rotary body 42 that are disposed inside the housing 40 and rotate while in contact with each other.
- the heating rotary body 41 is a driving rotary body and rotates in a direction indicated by an arrow.
- the heating rotary body 41 is a fixing member for heating and is in a roller form or a belt-pad form, and the circumferential surface of the heating rotary body 41 is heated to a prescribed temperature by a heater 43 .
- the pressurizing rotary body 42 is a fixing member for pressurization that is in a roller form or a belt-pad form and is disposed so as to be aligned substantially along the axial direction of the heating rotary body 41 .
- the pressurizing rotary body 42 is in contact with the heating rotary body 41 at a prescribed pressure and is rotated by the heating rotary body 41 .
- the contact portion between the heating rotary body 41 and the pressurizing rotary body 42 serves as a fixing treatment section FN through which a recording paper sheet 9 with a non-fixed toner image transferred thereon passes to thereby subject it to prescribed fixing treatment (heating, pressurization, etc.).
- a transport path Rt for transportation of a recording paper sheet 9 is provided in the housing 10 .
- the transport path Rt includes a supply transport path Rt 1 , a relay transport path Rt 2 , and an output the transport path Rt 3 .
- the supply transport path Rt 1 connects the delivery unit 33 of the paper feeder 3 to the transfer position (a portion of the photoreceptor drum 21 that faces the transfer device 25 ) of the image forming unit 2 .
- the supply transport path Rt 1 is composed of a pair of transport rollers 34 and unillustrated plural transport guide members.
- the pair of transport rollers 34 are composed of so-called resist rollers.
- the resist rollers in a non-rotating state have the function of correcting the inclination of a transported recording paper sheet 9 .
- the resist rollers start rotating at the timing of transfer, and the rotating resist rollers have the function of feeding a recording paper sheet 9 to the transfer position.
- the relay transport path Rt 2 connects the transfer position of the image forming unit 2 to the fixing treatment section of the fixing device 4 .
- the relay transport path Rt 2 is composed of a prescribed guide member 35 .
- the output transport path Rt 3 connects the fixing treatment section FN of the fixing device 4 to the paper outlet 12 .
- the output transport path Rt 3 is composed of a pair of first output rollers 36 , a pair of second output rollers 37 , plural output guiding members 38 and 39 , etc.
- the pair of first output rollers 36 is disposed on the paper outlet side of the housing 40 of the fixing device 4 and includes a driving roller 361 and a driven roller 362 that is pressed against the driving roller 361 and driven to rotate by the driving roller 361 .
- the pair of second output rollers 37 is disposed at the paper outlet 12 and includes a driving roller 372 and a driven roller 371 that is in contact with the driving roller 372 and is driven to rotate by the driving roller 372 .
- a support structure for the pair of first output rollers 36 will be described later.
- the output guiding members 38 are a pair of members 38 a and 38 b that face each other so as to form a transport space through which a recording paper sheet 9 subjected to fixation is guided to the pair of first output rollers 36 .
- the output guiding members 39 are a pair of members 39 a and 39 b that face each other so as to form a transport space through which a recording paper sheet 9 discharged from the pair of first output rollers 36 is guided to the pair of second output rollers 37 .
- an image is formed as described below. An image forming operation for forming an image on one side of a recording paper sheet 9 will be described.
- an unillustrated controller in the image forming apparatus 1 receives an image formation request, the image forming unit 2 , the paper feeder 3 , and the fixing device 4 are actuated.
- the photoreceptor drum 21 starts rotating.
- the charging device 22 charges the circumferential surface of the photoreceptor drum 21 to a predetermined potential with a predetermined polarity (a negative polarity in this embodiment), and then the exposure device 23 exposes the charged circumferential surface of the photoreceptor drum 21 to light according to image information to thereby form an electrostatic latent image having a prescribed pattern.
- the developing device 24 supplies a toner serving as a developer and charged to a prescribed polarity (a negative polarity in this embodiment) to the electrostatic latent image formed on the circumferential surface of the photoreceptor drum 21 to develop the electrostatic latent image, and the electrostatic latent image is thereby converted to a visible toner image.
- a prescribed polarity a negative polarity in this embodiment
- the rotating photoreceptor drum 21 transfers the toner image to the transfer position facing the transfer device 25 .
- the delivery unit 33 of the paper feeder 3 feeds a recording paper sheet 9 to the supply transport path Rt 1 according to transfer timing, and the pair of resist rollers 34 in the supply transport path Rt 1 delivers the recording paper sheet 9 to the transfer position.
- the transfer device 25 transfers the toner image on the photoreceptor drum 21 onto one side of the recording paper sheet 9 through electrostatic action at the transfer position.
- the cleaning device 26 cleans the circumferential surface of the photoreceptor drum 21 and other portions to prepare for the next image forming process.
- the rotational force of the rotating photoreceptor drum 21 causes the recording paper sheet 9 with the toner image transferred thereon to be delivered to the relay transport path Rt 2 and transported to the fixing device 4 .
- the recording paper sheet 9 is introduced into the fixing treatment section FN between the heating rotary body 41 and the pressurizing rotary body 42 driven to rotate by the heating rotary body 41 .
- the toner image on the recording paper sheet 9 is heated and fused under pressure and is thereby fixed to the recording paper sheet 9 .
- the recording paper sheet 9 subjected to fixation is transported through the output transport path Rt 3 to the paper outlet 12 of the housing 10 and then ejected and placed in the output tray 11 .
- the recording paper sheet 9 subjected to fixation is guided by the output guiding members 38 and the output guiding members 39 in the output transport path Rt 3 , held between the pair of first output rollers 36 and then between the pair of second output rollers 37 , and transported by the transportation force of the rollers.
- a single-color toner image is thereby formed on one side of the recording paper sheet 9 , and the single-side image formation operation is completed.
- the above series of operations is repeated the plural times.
- a support structure shown in FIGS. 3 to 6B etc. is used as the support structure supporting the pair of first output rollers 36 disposed in the output transport path Rt 3 .
- a rotary member 5 A including a rotating shaft 51 serving as a shaft and roller bodies 53 disposed on the outer circumferential surface of the rotating shaft 51 is used as the driving roller 361 .
- the driving roller 361 in exemplary embodiment 1 is a roller having a structure including the plural roller bodies 53 disposed on the rotating shaft 51 at prescribed intervals.
- a rotary member 5 B including a rotating shaft 52 serving as a shaft and a roller body 54 disposed on the outer circumferential surface of the rotating shaft 52 is used as the driven roller 362 .
- the driven roller 362 in exemplary embodiment 1 is a roller having a structure including one roller body 54 disposed on the rotating shaft 52 .
- the pair of first output rollers 36 has a structure in which the rotating shafts 51 and 52 are rotatably supported by prescribed support members 70 through bearings 55 and 56 , respectively, such that the roller bodies 53 and 54 of the driving roller 361 and the driven roller 362 , respectively, forming the rotary members 5 A and 5 B rotate while in contact with each other.
- the support members 70 are plate members such as synthetic resin plates or metallic plates fixed to prescribed positions.
- the pair of first output rollers 36 forms a transport device 7 that transports a recording paper sheet 9 , which is an example of a transportation object. Specifically, the recording paper sheet 9 is transported while sandwiched between the driving roller 361 and the driven roller 362 driven to rotate by the driving roller 361 .
- the driving roller 361 is driven to rotate in a prescribed direction by rotating power transmitted to the rotating shaft 51 from a rotation driving device 77 .
- the rotating power is transmitted from the rotation driving device 77 to the driving roller 361 (to its rotating shaft 51 ) using an unillustrated rotation transmitting mechanism such as a gear train.
- the bearings 55 rotatably supporting the rotating shaft 51 are fixed to respective stationary attachment members 71 disposed in the support members 70 , and the driving roller 361 is thereby attached to the support members 70 .
- the stationary attachment members 71 include, for example, holes or recesses into which the bearings 55 are partially fitted and members which fix the bearings 55 .
- the bearings 55 are, for example, sliding bearings.
- the bearings 56 rotatably supporting the rotating shaft 52 are attached to movable attachment members 72 disposed in the support members 70 so as to be movable by a given distance toward the driving roller 361 as shown by double-pointed arrows E 1 -E 2 .
- Each of the movable attachment members 72 includes a support 73 that supports a corresponding bearing 5 for the driven roller 362 movably with respect to the rotating shaft 51 of the driving roller 361 .
- the supports 73 are attached and fixed to the respective support members 70 .
- the bearings 56 are, for example, sliding bearings.
- the supports 73 may be formed as portions of the support members 70 and integrated therewith.
- the bearings 56 supporting the rotating shaft 52 are supported by the movable attachment members 72 so as to be pressed by respective pressing members 57 in a direction E 1 directed toward the rotating shaft 51 of the driving roller 361 .
- the driving roller 361 (the rotary member 5 A) is rotatably supported by the support members 70 (their stationary attachment members 71 ) while the position of the driving roller 361 is fixed.
- the driven roller 362 (the rotary member 5 B) is rotatably supported by the supports 73 (the movable attachment members 72 ) of the support members 70 so as to be movable toward the driving roller 361 and is also supported by the pressing members 57 through the bearings 56 so as to be pressed in the direction E 1 directed toward the rotating shaft 51 of the driving roller 361 .
- the driven roller 362 (the rotary member 5 B) employs a support structure 6 including: the bearings 56 that rotatably support the rotating shaft 52 ; the pressing members 57 that press the respective bearings 56 in the direction E 1 directed toward the rotating shaft 51 of the driving roller 361 ; and the supports 73 that support the respective bearings 56 so as to be movable in the direction E 1 in which the bearings 56 are pressed by the pressing members 57 .
- each of the bearings 56 in the support structure 6 includes a plate-shaped body 56 a having a substantially rectangular side portion.
- Each body 56 a includes: a bearing hole 56 b located at substantially the center and passing through the body 56 a ; a step portion 56 c that is disposed in an upper outer portion of the body 56 a and extends in the moving direction E 1 -E 2 ; and a pressure receiving portion 56 d that receives the pressure of a corresponding pressing member 57 on one side.
- each support 73 in the support structure 6 includes a body 74 having a holding portion 74 a that accommodates a corresponding bearing 56 such that upper and lower portions of the bearing 56 are held so as to be movable in the direction E 1 -E 2 .
- the body 74 includes: a lower guiding portion 74 b that holds and guides the lower side surface of the bearing 56 when it moves; an upper guiding portion 74 c that holds and guides the upper side surface (the step portion 56 c ) of the bearing 56 when it moves; and an abutting portion 74 d against which part of the pressing member 57 abuts to fix the pressing member 57 .
- each of the pressing members 57 in the support structure 6 is composed of a member that can elastically press a corresponding bearing 56 in the direction E 1 directed toward the rotating shaft 51 of the driving roller 361 .
- Each of the pressing members 57 in exemplary embodiment 1 includes a coil spring.
- Each of the coil springs of the pressing members 57 is disposed between the pressure receiving portion 56 d of a corresponding bearing 56 and the abutting portion 74 d of a corresponding support 73 and is used such that the bearing 56 is pressed by prescribed pressing force F toward the rotation center ( 02 ) of the rotating shaft 52 of the driven roller 362 .
- a protrusion holding portion 74 e that holds one end of the coil spring used as the pressing member 57 is provided.
- the protrusion holding portion 74 e is fitted into an internal space at the one end of the coil, and the coil spring is thereby held. Since the one end of the coil spring is held by the protrusion holding portion 74 e , the position of the coil spring is unlikely to be displaced.
- each coil spring included in a corresponding pressing member 57 is disposed such that its end portion opposite to the abutting portion 74 d of a corresponding support 73 is pressed against part of a corresponding bearing 56 .
- the support structure 6 shown in FIG. 15A is a comparative support structure 60 . Both ends of the coil spring serving as the pressing member 57 are assumed to be parallel to each other and have a substantially flat annular shape, unless otherwise specifically stated.
- Symbol L 1 for a chain dashed line in FIG. 15A etc. represents a virtual straight line (virtual line) connecting the rotation center 02 of the driven roller 362 to the rotation center 01 of the driving roller 361 .
- Symbol L 2 for a chain dashed line represents the direction (the axial line) of the rotating shaft 52 of the driven roller 362 .
- the coil spring serving as the pressing member 57 is disposed such that a central portion 57 a of an end of the coil spring that is pressed against part of the bearing 56 substantially coincides with a position P 1 at which the virtual line L 1 intersects a pressure receiving surface 56 e of the bearing 56 and is in contact with the pressure receiving surface 56 e .
- FIG. 15B shows a portion 57 b in which an end portion of the coil spring serving as the pressing member 57 is in contact with the pressure receiving surface 56 e of the bearing 56 and also shows the state of the portion 57 b .
- the coil spring serving as the pressing member 57 is attached on the assumption that the pressing force F of the coil spring acts toward the rotation center 02 of the rotating shaft 52 .
- a rotational force (moment) Mr and a rotational drag force (moment) Mb are generated and act on the bearing 56 .
- the rotational force Mr urges the bearing 56 to rotate in the rotation direction C through the frictional force such as the sliding force between the bearing 56 and the rotating shaft 52 of the driven roller 362 .
- the rotational drag force Mb is caused by the pressing member 57 pressed against the bearing 56 and urges the bearing 56 to rest against the rotational force Mr.
- each bearing 56 may rotate about the rotating shaft 52 and come to rest while in contact with part of the holding portion 74 a of the support 73 and inclined within a movable space in the support 73 .
- FIG. 16A shows a state (J 1 ) in which the bearing 56 slides within the holding portion 74 a of the support 73 in a direction opposite to the rotation direction C of the driven roller 362 and is thereby inclined and at rest.
- FIG. 16B shows a state (J 2 ) in which the bearing 56 slides within the holding portion 74 a of the support 73 in the rotation direction C of the driven roller 362 and is thereby inclined and at rest.
- the rotational force Mr may increase or decrease. Specifically, when a reduction in the sliding friction occurs, the rotational force Mr decreases. In this case, the rotational force Mr can be substantially equal to the rotational drag force Mb (Mr ⁇ Mb).
- the bearing 56 When these forces are substantially equal to each other, the bearing 56 is unstable and can easily rotate about the rotating shaft 52 during rotation of the driven roller 362 . Therefore, the bearing 56 rotates back and forth repeatedly between the above two states (J 1 and J 2 ).
- the bearing 56 repeatedly collides with portions of the support 73 , and this causes unwanted noise and vibration.
- unwanted noise and vibration are generated during transfer of a recording paper sheet 9 by the transport device 7 .
- a support structure 6 A shown in FIGS. 4A and 5A is employed as the support structure 6 that supports the driven roller 362 of the pair of first output rollers 36 .
- the bearing 56 and the pressing member 57 are in contact with each other while the bearing 56 is rotatable about the rotating shaft 52 .
- the state in which the bearing 56 is rotatable is an unstable state. Specifically, for example, when the driven roller 362 is not rotating, the bearing 56 can easily rotate about the rotating shaft 52 in the rotation direction C of the driven roller 362 (or its rotating shaft 52 ) and also in a direction opposite to the rotation direction C, as shown in FIG. 6A .
- Symbol L 1 for a chain dashed line in FIG. 6A represents a virtual line connecting the rotation center 02 of the driven roller 362 to the rotation center 01 of the driving roller 361 , as does the virtual line L 1 described above.
- each pressing member 57 has a protrusion 81 , and the protrusion 81 is in contact with a corresponding bearing 56 .
- the bearing 56 can rotate about the rotating shaft 52 .
- the bearing 56 is held in a state in which it is rotated in the rotation direction C of the driven roller 362 , as shown in FIG. 6B .
- the bearing 56 is held in a state in which it is rotated in the rotation direction C of the driven roller 362 ” means that, for example, the bearing 56 rotated in the rotation direction C of the driven roller 362 comes into contact with part of the holding portion 74 a of the support 73 and is thereby inclined and at rest and the inclined state is maintained during the rotation of the driven roller 362 , as shown in FIG. 6B .
- the phrase also encompasses the following case.
- the bearing 56 is brought to the inclined state described above. Then the bearing 56 in the inclined state slightly rotates continuously back and forth in the rotation direction C of the driven roller 362 and its reverse rotation direction. In other words, in this state, during the rotation of the driven roller 362 in the rotation direction C, the bearing 56 is prevented from rotating in the reverse rotation direction beyond the position at which the bearing 56 is unstable and rotatable when the driven roller 362 is not rotating ( FIG. 6A ).
- the protrusion 81 disposed in the pressing member 57 is formed as a structural member having a spherical surface portion that comes in to contact with the pressure receiving surface 56 e of the pressure receiving portion 56 d of the bearing 56 .
- the protrusion 81 formed as the spherical surface-shaped structural member is in point contact with the pressure receiving surface 56 e of the pressure receiving portion 56 d of the bearing 56 . This allows the bearing 56 to be easily rotatable when the driven roller 362 is not rotating.
- Symbol 81 a in FIG. 5B represents a portion of the protrusion 81 that is in contact with the bearing 56 .
- the contact portion 81 a substantially corresponds to the apex of the spherical surface-shaped protrusion 81 .
- a chain dashed line L 2 in FIG. 5B indicates the direction (axial line) of the rotating shaft 52 of the driven roller 362 as described above.
- the term “point contact” also encompasses the case in which the shape of the contact portion 81 a is a dot-like shape (a small circular shape) with a certain diameter (width) w 1 on condition that shape of the contact portion 81 a is maintained in the above-described rotatable state as shown in FIG. 5B .
- the pressure receiving surface 56 e of the pressure receiving portion 56 d of the bearing 56 is a flat surface.
- the pressure receiving surface 56 e may be a curved surface with a small curvature so long as the point contact with the protrusion 81 can be maintained.
- the pressing member 57 provided with the protrusion 81 includes a coil spring 571 having a first end 571 a to which a component 85 having the protrusion 81 is attached.
- the component 85 having the protrusion 81 has an attachment recess 85 c into which the first end 571 a of the coil spring 571 is fitted.
- the protrusion 81 may be integrated with the component 85 , or the protrusion 81 formed separately may be later integrated with the component 85 .
- the pressing member 57 provided with the protrusion 81 is disposed such that the protrusion 81 is pressed toward the rotation center 02 of the rotating shaft 52 of the driven roller 362 . Specifically, as shown in FIG. 6A , the pressing member 57 is disposed such that its pressing force F acts toward the rotation center 02 of the rotating shaft 52 .
- the coil spring 571 serving as the pressing member 57 may be attached such that a second end 571 b of the coil spring 571 is fitted onto and held by the protrusion holding portion 74 e ( FIG. 4A ) provided in the abutting portion 74 d of the support 73 .
- the bearing 56 is rotatable about the rotating shaft 52 within the movable space in the holding portion 74 a of the support 73 .
- the bearing 56 is in an unstable state in which it can easily rotate about the rotating shaft 52 in the rotation direction C of the driven roller 362 and also in the reverse rotation direction.
- the bearing 56 that is rotatable when the driven roller 362 is not rotating is maintained in a state in which the bearing 56 is rotated in the rotation direction C of the driven roller 362 within the movable space in the holding portion 74 a of the support 73 .
- the bearing 56 in this case is rotated in the rotation direction C of the driven roller 362 within the movable space in the holding portion 74 a of the support 73 . Then part (a corner) of the bearing 56 comes into contact with part of the holding portion 74 a , and the bearing 56 comes to rest, so that the bearing 56 is slightly inclined.
- the sliding friction between the bearing 56 and the rotating shaft 52 may change instantaneously, and the rotational force Mr may increase or decrease, as described above for the comparative support structure 60 .
- the rotational force Mr decreases.
- the rotational force Mr and the rotational drag force Mb may become substantially equal to each other (Mr ⁇ Mb).
- the protrusion 81 in the pressing member 57 is in point contact with the bearing 56 . Since the pressing member 57 is disposed such that its pressing force F acts toward the rotation center 02 of the rotating shaft 52 , the vector of the load generated by the protrusion 81 is directed toward the rotation center 02 of the rotating shaft 52 . Therefore, in the support structure 6 A, the rotational drag force (moment) Mb itself that is caused by the pressing member 57 pressed against the bearing 56 and urges the bearing 56 to rest against the rotational force Mr is unlikely to be generated.
- the rotational drag force Mb is unlikely to increase to a level comparable to the rotational force Mr, and the relation between the rotational force Mr and the rotational drag force Mb is easily maintained such that the rotational force Mr is larger than the rotational drag force Mb (Mr>Mb).
- the bearing 56 is easily maintained in a state in which it is rotated in the rotation direction C of the driven roller 362 within the holding portion 74 a of the support 73 .
- the bearing 56 is prevented from rotating in the reverse rotation direction opposite to the rotation direction C beyond the position at which the bearing 56 is in the rotatable state when the driven roller 362 is not rotating and from rotating back and forth repeatedly around the above position.
- the generation of noise and vibration that occurs during rotation of the driven roller 362 in the comparative support structure 60 is prevented or reduced. Therefore, in a transport device 7 produced using the support structures 6 A, a recording paper sheet 9 can be smoothly transported without generation of noise and vibration.
- the protrusion 81 in point contact with the pressure receiving portion 56 d of the bearing 56 is a structural component having a spherical surface shape.
- this structural example is not a limitation.
- the protrusion 81 may be a structural component in which the portion in contact with the pressure receiving portion 56 d of the bearing 56 has a cone shape or a pyramid shape.
- FIGS. 8A and 8B show a support structure 6 B for the driven roller 362 in exemplary embodiment 2.
- the support structure 6 B according to exemplary embodiment 2 has the same structure as the support structure 6 A according to exemplary embodiment 1 except that the protrusion 81 is replaced with a protrusion 82 having a different structure. Therefore, in the support structure 6 B, the same components as the support structure 6 A are denoted by the same symbols in FIGS. 8A and 8B and subsequent figures, and their description will be omitted in principle.
- the protrusion disposed in the pressing member 57 is a protrusion 82 in line contact along the axial line L 2 of the rotating shaft 52 with the pressure receiving surface 56 e of the pressure receiving portion 56 d of the bearing 56 . Therefore, as shown in FIGS. 8A, 8B, and 9A , when the driven roller 362 is not rotating, the bearing 56 is rotatable about the rotating shaft 52 .
- the protrusion 82 is formed as a structural component in which its portion coming into contact with the pressure receiving surface 56 e of the bearing 56 can be in line contact along the axial line L 2 of the rotating shaft 52 . As shown in FIG. 10A , the protrusion 82 is formed as, for example, a horizontally extending triangular prism-shaped structural component having an edge line 82 a that comes into contact with the bearing 56 .
- the protrusion 82 having the portion capable of line contact comes into line contact with the pressure receiving surface 56 e of the pressure receiving portion 56 d of the bearing 56 .
- the bearing 56 when the driven roller 362 is not rotating, the bearing 56 can be easily brought to the above-described rotatable state.
- the bearing 56 is further prevented from being inclined accidentally in a direction intersecting the axial line L 2 , as compared to the case when the protrusion 81 in point contact is used. Therefore, the posture of the bearing 56 in the direction of the axial line L 2 is stabilized.
- line contact encompasses the case in which the contact portion 82 a of the protrusion 82 has a continuous or discontinuous rectangular shape with a certain width w 2 on condition that the bearing 56 is maintained in the above-described rotatable state, as shown in FIG. 8B .
- the width w 2 is shorter than the length k 1 of the contact portion 82 a along the axial line L 2 of the rotating shaft 52 (w 2 ⁇ k 1 ).
- the pressing member 57 provided with the protrusion 82 includes a coil spring 571 having an end to which a component 85 having the protrusion 82 is attached (e.g., FIG. 8A ), as is the pressing member 57 provided with the protrusion 81 ( FIGS. 7A and 7B ).
- the bearing 56 is rotatable about the rotating shaft 52 within the movable space in the holding portion 74 a of the support 73 .
- the bearing 56 is in an unstable state in which it can easily rotate in the rotation direction C of the driven roller 362 and also in the reverse rotation direction.
- the posture of the bearings 56 along the axial line L 2 of the rotating shaft 52 is in a stable state.
- the bearing 56 in this case is rotated in the rotation direction C of the driven roller 362 within the movable space in the holding portion 74 a of the support 73 . Then part (a corner) of the bearing 56 comes into contact with part of the holding portion 74 a , and the bearing 56 comes to rest, so that the bearing 56 is slightly inclined.
- the sliding friction between the bearing 56 and the rotating shaft 52 may change instantaneously, and the rotational force Mr may increase or decrease.
- the rotational force Mr and the rotational drag force Mb may become substantially equal to each other (Mr ⁇ Mb).
- the protrusion 82 in the pressing member 57 is in line contact with the bearing 56 . Since the pressing member 57 is disposed such that its pressing force F acts toward the rotation center 02 of the rotating shaft 52 , the vector of the load generated by the protrusion 82 is directed toward the rotation center 02 of the rotating shaft 52 . Therefore, in the support structure 6 B, as in the support structure 6 A, the rotational drag force Mb itself that is caused by the pressing member 57 pressed against the bearing 56 and urges the bearing 56 to rest against the rotational force Mr is unlikely to be generated.
- the rotational drag force Mb is unlikely to increase to a level comparable to the rotational force Mr, and the relation between the rotational force Mr and the rotational drag force Mb is easily maintained such that the rotational force Mr is larger than the rotational drag force Mb (Mr>Mb).
- the bearing 56 is easily maintained in a state in which it is rotated in the rotation direction C of the driven roller 362 within the holding portion 74 a of the support 73 .
- the bearing 56 is prevented from rotating in the reverse rotation direction opposite to the rotation direction C beyond the position at which the bearing 56 is in the rotatable state when the driven roller 362 is not rotating and from rotating back and forth repeatedly around the above position.
- the protrusion 82 in line contact may be, for example, a structural body including a semicylindrical member having an apex portion (ridge line) 82 b extending substantially linearly in a lengthwise direction, as shown in FIG. 10B .
- This structural body may be disposed such that the apex portion 82 b comes into contact with the bearing 56 .
- the apex portion 82 b of the protrusion 82 is less worn due to contact with the bearing 56 than the protrusion 82 of the structural body shown in FIG. 10A , and the bearing 56 can be maintained in a desirable state for a long time.
- FIG. 11 shows a support structure 6 C for the driven roller 362 in exemplary embodiment 3.
- the support structure 6 C according to exemplary embodiment 3 has the same structure as the support structure 6 A according to exemplary embodiment 1 except that the protrusion 81 is disposed in the bearing 56 . Therefore, in the support structure 6 C, the same components as the support structure 6 A are denoted by the same symbols in FIGS. 11A and 11B and subsequent figures, and their description will be omitted in principle.
- the protrusion disposed in the bearing 56 is a protrusion 83 that comes into point contact with one end of a coil spring serving as the pressing member 57 , as shown in FIGS. 11A and 11B . Therefore, as shown in FIGS. 11A, 11B, and 12A , when the driven roller 362 is not rotating, the bearing 56 is rotatable about the rotating shaft 52 .
- the protrusion 83 disposed in the bearing 56 is formed as a structural component in which its portion coming into contact with one end of the pressing member 57 has a spherical surface shape, as is the protrusion 81 in the support structure 6 A.
- the pressing member 57 is formed as, for example, a coil spring 571 to which a component 85 having a flat surface serving as a portion 85 a to be in contact with the protrusion 83 is attached to the one end.
- the protrusion 83 formed as the spherical surface-shaped structural body comes into point contact with the one end of the coil spring 571 serving as the pressing member 57 (the flat portion 85 a of the component 85 ). In this manner, when the driven roller 362 is not rotating, the bearing 56 can be easily brought to the above-described rotatable state.
- Symbol 83 a in FIG. 11B represents a portion of the protrusion 83 that is in contact with the one end of the coil spring 571 serving as the pressing member 57 .
- the contact portion 83 a substantially corresponds to the apex of the spherical surface-shaped protrusion 83 .
- the pressing member 57 is disposed so as to be pressed toward the rotation center 02 of the rotating shaft 52 of the driven roller 362 .
- the pressing member 57 is disposed such that its pressing force F acts toward the rotation center 02 of the rotating shaft 52 .
- the bearing 56 is rotatable about the rotating shaft 52 within the movable space in the holding portion 74 a of the support 73 .
- the bearing 56 is in an unstable state in which it can easily rotate in the rotation direction C of the driven roller 362 and also in the reverse rotation direction.
- the posture of the bearing 56 along the axial line L 2 of the rotating shaft 52 is in a stable state.
- the bearing 56 in this case is rotated in the rotation direction C of the driven roller 362 within the movable space in the holding portion 74 a of the support 73 . Then part (a corner) of the bearing 56 comes into contact with part of the holding portion 74 a , and the bearing 56 comes to rest, so that the bearing 56 is slightly inclined.
- the sliding friction between the bearing 56 and the rotating shaft 52 may change instantaneously, and the rotational force Mr may increase or decrease. Therefore, for example, the rotational force Mr and the rotational drag force Mb may become substantially equal to each other (Mr ⁇ Mb).
- the protrusion 83 in the bearing 56 is in point contact with the pressing member 57 . Since the pressing member 57 is disposed such that its pressing force F acts toward the rotation center 02 of the rotating shaft 52 , the vector of the load generated by the protrusion 83 is directed toward the rotation center 02 of the rotating shaft 52 . Therefore, in the support structure 6 C, the rotational drag force Mb itself that is caused by the pressing member 57 pressed against the bearing 56 and acts against the rotational force Mr is unlikely to be generated.
- the rotational drag force Mb is unlikely to increase to a level comparable to the rotational force Mr, and the relation between the rotational force Mr and the rotational drag force Mb is easily maintained such that the rotational force Mr is larger than the rotational drag force Mb (Mr>Mb).
- the bearing 56 is easily maintained in a state in which it is rotated in the rotation direction C of the driven roller 362 within the holding portion 74 a of the support 73 .
- the bearing 56 is prevented from rotating in the reverse rotation direction opposite to the rotation direction C beyond the position at which the bearing 56 is in the rotatable state when the driven roller 362 is not rotating and from rotating back and forth repeatedly around the above position.
- the protrusion 83 in point contact may be, for example, a different structural member such as that described in exemplary embodiment 1.
- the protrusion 82 in line contact as exemplified in exemplary embodiment 2 may be used instead of the protrusion 83 in point contact.
- FIG. 13 shows a support structure 6 D for a charging roller 220 in exemplary embodiment 4 and the charging device 22 using the support structure 6 D.
- This support structure 6 D supports the charging roller 220 in the charging device 22 of the image forming unit 2 .
- the support structure 6 A according to exemplary embodiment 1 ( FIGS. 4A, 4B, 5A, 5B , etc.) is used as the support structure 6 D.
- the charging roller 220 is a rotary member 5 C including, for example: a rotating shaft 221 to which a charging voltage is supplied; and a roller body 222 disposed on the rotating shaft 221 and having a multilayer structure including an elastic layer, a surface layer, etc.
- the charging roller 220 is in contact with the circumferential surface of the photoreceptor drum 21 rotating in the direction of arrow A and is driven to rotate by the photoreceptor drum 21 in a direction indicated by chain double-dashed arrow D, and the circumferential surface of the photoreceptor drum 21 is thereby charged.
- a chain dashed line L 3 in FIG. 13 etc. represents a virtual straight line (virtual line) connecting the rotation center 03 of the photoreceptor drum 21 to the rotation center 04 of the charging roller 220 .
- a double-pointed arrow denoted by symbols E 3 and E 4 indicates moving directions when the support 73 movably supports the bearing 56 of the charging roller 220 .
- the protrusion 81 disposed in the pressing member 57 is in point contact with the pressure receiving surface 56 e of the pressure receiving portion 56 d of the bearing 56 (see, for example, FIG. 6B ).
- the bearing 56 is rotatable about the rotating shaft 221 .
- the bearing 56 is rotatable about the rotating shaft 221 within the movable space in the holding portion 74 a of the support 73 .
- the bearing 56 in this case is rotated in the rotation direction D of the charging roller 220 within the movable space in the holding portion 74 a of the support 73 . Then part (a corner) of the bearing 56 comes into contact with part of the holding portion 74 a , and the bearing 56 comes to rest, so that the bearing 56 is slightly inclined.
- the sliding friction between the bearing 56 and the rotating shaft 221 may change instantaneously, and the rotational force Mr may increase or decrease.
- the rotational force Mr and the rotational drag force Mb may become substantially equal to each other (Mr ⁇ Mb).
- the rotational drag force Mb is unlikely to increase to a level comparable to the rotational force Mr, and the relation between the rotational force Mr and the rotational drag force Mb is easily maintained such that the rotational force Mr is larger than the rotational drag force Mb (Mr>Mb).
- the bearing 56 is easily maintained in a state in which it is rotated in the rotation direction D of the charging roller 220 within the holding portion 74 a of the support 73 .
- the bearing 56 is prevented from rotating in the reverse rotation direction opposite to the rotation direction C beyond the position at which the bearing 56 is in the rotatable state when the charging roller 220 is not rotating and from rotating back and forth repeatedly around the above position.
- the generation of noise and vibration during rotation of the charging roller 220 is prevented or reduced. Therefore, in the charging device 22 formed using the support structure 6 D, charging can be performed desirably without generation of noise and vibration.
- one of the support structures 6 A to 6 C is used as the structure for supporting the driven roller 362 (the rotary member 5 B) of the pair of first output rollers 36 .
- any of them may be used as a structure for supporting the driving roller 361 (the rotary member 5 A) of the pair of first output rollers 36 .
- the driving roller 361 may be replaced with an elastic roller having the function of correcting curl of a recording paper sheet 9 .
- the elastic roller is, for example, a continuous single roller such as the driven roller 362 , and an elastic body is used as its roller body.
- Each of the support structures 6 A to 6 C exemplified in exemplary embodiments 1 to 3 can be used for a transport device including a pair of transport rollers (rotary members) that are in pressure contact with each other and are rotated and transport a recording paper sheet 9 held therebetween.
- each of the support structures 6 A to 6 C can be used as a support structure for at least one of the pair of transport rollers.
- Each of the support structure 6 A to 6 C exemplified in exemplary embodiments 1 to 3 can be used as the support structure 6 D for the charging roller 220 in the charging device 22 of the image forming unit 2 exemplified in exemplary embodiment 4, but this is not a limitation.
- Each of the support structures 6 A to 6 C may be used as the support structure for a different rotary member. Examples of such a rotary member include a transfer roller and fixing roller.
- Each of the support structures 6 A to 6 C may be used as the support structure for a pressing roller pressed against a portion of an endless belt that is not supported by a support roller.
- a rotary member in contact with the pressing roller is a portion of the rotating belt that is not supported by the support roller.
- an image forming apparatus including the rotary member using one of the support structures 6 A to 6 D and the transport device 7 or the charging device 22 is not limited to the apparatus forming a monochrome image using a single-color toner as exemplified in exemplary embodiments 1 to 4. Image forming apparatuses of different types may be used.
- Examples of the image forming apparatuses of different types include: an image forming apparatus that forms a multicolor image using a combination of plural color toners; and an image forming apparatus that forms an image by jetting ink droplets.
- the rotary member and the transport device 7 that use any of the support structures 6 A to 6 C may be a rotary member and a transport device of an apparatus other than the image forming apparatus.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Plasma & Fusion (AREA)
- General Physics & Mathematics (AREA)
- Delivering By Means Of Belts And Rollers (AREA)
- Electrophotography Configuration And Component (AREA)
- Electrostatic Charge, Transfer And Separation In Electrography (AREA)
- Sliding-Contact Bearings (AREA)
- Support Of The Bearing (AREA)
- Rolls And Other Rotary Bodies (AREA)
- Mounting Of Bearings Or Others (AREA)
- Paper Feeding For Electrophotography (AREA)
Abstract
A rotary member support structure includes: a rotary member including a shaft; a bearing that rotatably supports the shaft of the rotary member; a pressing member that presses the bearing in one direction; and a support that supports the bearing such that the bearing is movable in a pressing direction of the pressing member. When the rotary member is not rotating, the bearing and the pressing member are in contact with each other such that the bearing is rotatable about the shaft.
Description
- This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2017-233292 filed Dec. 5, 2017.
- The present invention relates to a rotary member support structure, to a transport device, to a charging device, and to an image forming apparatus.
- According to an aspect of the invention, there is provided a rotary member support structure including: a rotary member including a shaft; a bearing that rotatably supports the shaft of the rotary member; a pressing member that presses the bearing in one direction; and a support that supports the bearing such that the bearing is movable in a pressing direction of the pressing member. When the rotary member is not rotating, the bearing and the pressing member are in contact with each other such that the bearing is rotatable about the shaft.
- Exemplary embodiments of the present invention will be described in detail based on the following figures, wherein:
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FIG. 1 is a schematic diagram showing the structure of an image forming apparatus; -
FIG. 2 is an enlarged schematic diagram showing an output transport path near a fixing device in the image forming apparatus inFIG. 1 ; -
FIG. 3 is a partial schematic cross sectional view showing the structure of a pair of first output rollers in the output transport path inFIG. 2 (the structure includes support structures); -
FIG. 4A is a schematic diagram showing a support structure for a driven roller in the pair of output rollers inFIG. 3 in exemplary embodiment 1; -
FIG. 4B is a schematic cross-sectional view taken along line IVB-IVB inFIG. 4A ; -
FIG. 5A is an enlarged schematic diagram showing the support structure for the driven roller inFIG. 4A ; -
FIG. 5B is a schematic diagram showing a contact state of a protrusion in the support structure inFIG. 5A ; -
FIG. 6A is a schematic diagram showing a state when the driven roller in the support structure inFIG. 5A is not rotating; -
FIG. 6B is a schematic diagram showing a state during rotation of the driven roller in the support structure inFIG. 6A ; -
FIG. 7A is an exploded perspective view showing the structure of a pressing member including the protrusion in the support structure inFIG. 5A ; -
FIG. 7B is a schematic cross-sectional view showing the pressing member inFIG. 7A ; -
FIG. 8A is an enlarged schematic diagram showing a support structure for the driven roller inexemplary embodiment 2; -
FIG. 8B is a schematic diagram showing a contact state of a protrusion in the support structure; -
FIG. 9A is a schematic diagram showing a state when the driven roller in the support structure inFIG. 8A is not rotating; -
FIG. 9B is a schematic diagram showing a state during rotation of the driven roller in the support structure inFIG. 9A ; -
FIG. 10A is a schematic perspective view showing the structure of the protrusion in the support structure inFIG. 8A ; -
FIG. 10B is a schematic perspective view showing another example of the structure of the protrusion in the support structure; -
FIG. 11A is an enlarged schematic diagram showing a support structure for the driven roller inexemplary embodiment 3; -
FIG. 11B is a schematic diagram showing a contact state of a protrusion in the support structure; -
FIG. 12A is a schematic diagram showing a state when the driven roller in the support structure inFIG. 11A is not rotating; -
FIG. 12B is a schematic diagram showing a state during rotation of the driven roller in the support structure inFIG. 12A ; -
FIG. 13 is an enlarged schematic diagram showing a support structure for a charging roller inexemplary embodiment 4; -
FIG. 14A is a schematic diagram showing a state when the charging roller in the support structure inFIG. 13 is not rotating; -
FIG. 14B is a schematic diagram showing a state during rotation of the charging roller in the support structure inFIG. 14A ; -
FIG. 15A is an enlarged schematic diagram showing a comparative support structure for the driven roller; -
FIG. 15B is a schematic diagram showing a contact state between a pressing member and a bearing in the support structure; -
FIG. 16A is a schematic diagram showing a state when the driven roller in the support structure inFIG. 15A is not rotating; and -
FIG. 16B is a schematic diagram showing a state during rotation of the driven roller in the support structure inFIG. 16A . - Exemplary embodiments of the present invention will next be described with reference to the drawings.
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FIGS. 1 and 2 show exemplary embodiment 1 of the invention.FIG. 1 shows the structure of an image forming apparatus 1 according to exemplary embodiment 1.FIG. 2 is an enlarged illustration of an output transport path in the image forming apparatus 1 inFIG. 1 . - In the image forming apparatus 1, an image based on the information about an image including letters, photographs, diagrams, etc. is formed using a developer on a
recording paper sheet 9 that is an example of a transportation object or a recording medium. - As shown in
FIG. 1 , the image forming apparatus 1 includes: ahousing 10 serving as an apparatus body; animage forming unit 2 that forms a toner image using a toner serving as the developer by, for example, electrophotography and transfers the toner image onto arecording paper sheet 9; apaper feeder 3 that holds a prescribed number ofrecording paper sheets 9 and feeds arecording paper sheet 9 to a transfer position of theimage forming unit 2; and afixing device 4 that fixes the toner image transferred onto therecording paper sheet 9. Theimage forming unit 2, thepaper feeder 3, and the fixingdevice 4 are disposed inside thehousing 10. - The
housing 10 is composed of various members such as structural members and exterior materials. Anoutput tray 11 for placing ejectedrecording paper sheets 9 with images formed thereon is provided in an upper portion of thehousing 10. Theoutput tray 11 is formed as a collecting surface having an inclined surface disposed below apaper outlet 12 of thehousing 10 and is configured to collectrecording paper sheets 9 ejected from thepaper outlet 12. - The
image forming unit 2 includes aphotoreceptor drum 21 that is a driving drum and rotates in a direction indicated by arrow A and further includes a chargingdevice 22, anexposure device 23, a developingdevice 24, atransfer device 25, and acleaning device 26 that are disposed in this order around thephotoreceptor drum 21. - The charging
device 22 is, for example, a contact charging device that electrically charges the circumferential surface (the outer circumferential surface serving as an image-forming region) of thephotoreceptor drum 21 to a prescribed potential with a prescribed polarity. Theexposure device 23 irradiates the circumferential surface of the chargedphotoreceptor drum 21 with light (indicated by a chain double-dashed arrow) in response to image information (signals) inputted in various forms to the image forming apparatus 1 to thereby form an electrostatic latent image. The developingdevice 24 supplies a charged toner used as a developer to develop the electrostatic latent image on thephotoreceptor drum 21, and a toner image is thereby formed. Thetransfer device 25 is, for example, a contact transfer device that electrostatically transfers the toner image on thephotoreceptor drum 21 onto arecording paper sheet 9. Thecleaning device 26 cleans thephotoreceptor drum 21 by removing undesired substances such as the toner remaining on the circumferential surface of thephotoreceptor drum 21. - The
paper feeder 3 includes: apaper tray 31 that holds pluralrecording paper sheets 9 having a prescribed size and a prescribed type and used for image formation, therecording paper sheets 9 being stacked on asheet stacking plate 32; and adelivery unit 33 that delivers therecording paper sheets 9 held in thepaper tray 31 one by one. - The
paper tray 31 is attached to thehousing 10 such that thepaper tray 31 can be pulled out of thehousing 10, andplural paper trays 31 may be provided depending on use conditions. Therecording paper sheets 9 used are, for example, recording mediums cut into a prescribed size such as plain paper sheets, coated paper sheets, or thick paper sheets. - The fixing
device 4 includes ahousing 40 having an inlet for arecording paper sheet 9 and a paper outlet and further includes aheating rotary body 41 and a pressurizingrotary body 42 that are disposed inside thehousing 40 and rotate while in contact with each other. - As shown in
FIGS. 1 and 2 etc., theheating rotary body 41 is a driving rotary body and rotates in a direction indicated by an arrow. Theheating rotary body 41 is a fixing member for heating and is in a roller form or a belt-pad form, and the circumferential surface of theheating rotary body 41 is heated to a prescribed temperature by aheater 43. The pressurizingrotary body 42 is a fixing member for pressurization that is in a roller form or a belt-pad form and is disposed so as to be aligned substantially along the axial direction of theheating rotary body 41. The pressurizingrotary body 42 is in contact with theheating rotary body 41 at a prescribed pressure and is rotated by theheating rotary body 41. In thefixing device 4, the contact portion between theheating rotary body 41 and the pressurizingrotary body 42 serves as a fixing treatment section FN through which arecording paper sheet 9 with a non-fixed toner image transferred thereon passes to thereby subject it to prescribed fixing treatment (heating, pressurization, etc.). - In the image forming apparatus 1, as shown by a chain double-dashed line in
FIG. 1 , a transport path Rt for transportation of arecording paper sheet 9 is provided in thehousing 10. The transport path Rt includes a supply transport path Rt1, a relay transport path Rt2, and an output the transport path Rt3. - As shown in
FIG. 1 , the supply transport path Rt1 connects thedelivery unit 33 of thepaper feeder 3 to the transfer position (a portion of thephotoreceptor drum 21 that faces the transfer device 25) of theimage forming unit 2. The supply transport path Rt1 is composed of a pair oftransport rollers 34 and unillustrated plural transport guide members. - The pair of
transport rollers 34 are composed of so-called resist rollers. The resist rollers in a non-rotating state have the function of correcting the inclination of a transportedrecording paper sheet 9. The resist rollers start rotating at the timing of transfer, and the rotating resist rollers have the function of feeding arecording paper sheet 9 to the transfer position. - As shown in
FIG. 1 , the relay transport path Rt2 connects the transfer position of theimage forming unit 2 to the fixing treatment section of the fixingdevice 4. The relay transport path Rt2 is composed of aprescribed guide member 35. - As shown in
FIGS. 1 and 2 etc., the output transport path Rt3 connects the fixing treatment section FN of the fixingdevice 4 to thepaper outlet 12. The output transport path Rt3 is composed of a pair offirst output rollers 36, a pair ofsecond output rollers 37, pluraloutput guiding members 38 and 39, etc. - The pair of
first output rollers 36 is disposed on the paper outlet side of thehousing 40 of the fixingdevice 4 and includes a drivingroller 361 and a drivenroller 362 that is pressed against the drivingroller 361 and driven to rotate by the drivingroller 361. The pair ofsecond output rollers 37 is disposed at thepaper outlet 12 and includes a drivingroller 372 and a drivenroller 371 that is in contact with the drivingroller 372 and is driven to rotate by the drivingroller 372. A support structure for the pair offirst output rollers 36 will be described later. - The
output guiding members 38 are a pair ofmembers recording paper sheet 9 subjected to fixation is guided to the pair offirst output rollers 36. The output guiding members 39 are a pair ofmembers recording paper sheet 9 discharged from the pair offirst output rollers 36 is guided to the pair ofsecond output rollers 37. - In the image forming apparatus 1, an image is formed as described below. An image forming operation for forming an image on one side of a
recording paper sheet 9 will be described. - First, when an unillustrated controller in the image forming apparatus 1 receives an image formation request, the
image forming unit 2, thepaper feeder 3, and the fixingdevice 4 are actuated. - Then, in the
image forming unit 2, thephotoreceptor drum 21 starts rotating. The chargingdevice 22 charges the circumferential surface of thephotoreceptor drum 21 to a predetermined potential with a predetermined polarity (a negative polarity in this embodiment), and then theexposure device 23 exposes the charged circumferential surface of thephotoreceptor drum 21 to light according to image information to thereby form an electrostatic latent image having a prescribed pattern. Next, the developingdevice 24 supplies a toner serving as a developer and charged to a prescribed polarity (a negative polarity in this embodiment) to the electrostatic latent image formed on the circumferential surface of thephotoreceptor drum 21 to develop the electrostatic latent image, and the electrostatic latent image is thereby converted to a visible toner image. - Next, in the
image forming unit 2, the rotatingphotoreceptor drum 21 transfers the toner image to the transfer position facing thetransfer device 25. Thedelivery unit 33 of thepaper feeder 3 feeds arecording paper sheet 9 to the supply transport path Rt1 according to transfer timing, and the pair of resistrollers 34 in the supply transport path Rt1 delivers therecording paper sheet 9 to the transfer position. Then, in theimage forming unit 2, thetransfer device 25 transfers the toner image on thephotoreceptor drum 21 onto one side of therecording paper sheet 9 through electrostatic action at the transfer position. In theimage forming unit 2, after the image transfer, thecleaning device 26 cleans the circumferential surface of thephotoreceptor drum 21 and other portions to prepare for the next image forming process. - Next, in the
image forming unit 2, the rotational force of therotating photoreceptor drum 21 causes therecording paper sheet 9 with the toner image transferred thereon to be delivered to the relay transport path Rt2 and transported to thefixing device 4. In thefixing device 4, therecording paper sheet 9 is introduced into the fixing treatment section FN between theheating rotary body 41 and the pressurizingrotary body 42 driven to rotate by theheating rotary body 41. When therecording paper sheet 9 passes through the fixing treatment section FN, the toner image on therecording paper sheet 9 is heated and fused under pressure and is thereby fixed to therecording paper sheet 9. - Finally, the
recording paper sheet 9 subjected to fixation is transported through the output transport path Rt3 to thepaper outlet 12 of thehousing 10 and then ejected and placed in theoutput tray 11. - In this case, as shown in
FIGS. 1 and 2 , therecording paper sheet 9 subjected to fixation is guided by theoutput guiding members 38 and the output guiding members 39 in the output transport path Rt3, held between the pair offirst output rollers 36 and then between the pair ofsecond output rollers 37, and transported by the transportation force of the rollers. - A single-color toner image is thereby formed on one side of the
recording paper sheet 9, and the single-side image formation operation is completed. When an instruction to perform the image forming operation plural times is issued, the above series of operations is repeated the plural times. - In the image forming apparatus 1, a support structure shown in
FIGS. 3 to 6B etc. is used as the support structure supporting the pair offirst output rollers 36 disposed in the output transport path Rt3. - First, as shown in
FIG. 3 etc., in the pair offirst output rollers 36, a rotary member 5A including arotating shaft 51 serving as a shaft androller bodies 53 disposed on the outer circumferential surface of therotating shaft 51 is used as the drivingroller 361. The drivingroller 361 in exemplary embodiment 1 is a roller having a structure including theplural roller bodies 53 disposed on therotating shaft 51 at prescribed intervals. - As shown in
FIG. 3 etc., in the pair offirst output rollers 36, a rotary member 5B including arotating shaft 52 serving as a shaft and aroller body 54 disposed on the outer circumferential surface of therotating shaft 52 is used as the drivenroller 362. The drivenroller 362 in exemplary embodiment 1 is a roller having a structure including oneroller body 54 disposed on therotating shaft 52. - The pair of
first output rollers 36 has a structure in which therotating shafts prescribed support members 70 throughbearings roller bodies roller 361 and the drivenroller 362, respectively, forming the rotary members 5A and 5B rotate while in contact with each other. - The
support members 70 are plate members such as synthetic resin plates or metallic plates fixed to prescribed positions. - As shown in
FIGS. 1 to 3 etc., the pair offirst output rollers 36 forms a transport device 7 that transports arecording paper sheet 9, which is an example of a transportation object. Specifically, therecording paper sheet 9 is transported while sandwiched between the drivingroller 361 and the drivenroller 362 driven to rotate by the drivingroller 361. - As shown in
FIG. 3 , the drivingroller 361 is driven to rotate in a prescribed direction by rotating power transmitted to therotating shaft 51 from arotation driving device 77. The rotating power is transmitted from therotation driving device 77 to the driving roller 361 (to its rotating shaft 51) using an unillustrated rotation transmitting mechanism such as a gear train. - In the driving
roller 361 in the above support structure, thebearings 55 rotatably supporting therotating shaft 51 are fixed to respectivestationary attachment members 71 disposed in thesupport members 70, and the drivingroller 361 is thereby attached to thesupport members 70. - The
stationary attachment members 71 include, for example, holes or recesses into which thebearings 55 are partially fitted and members which fix thebearings 55. Thebearings 55 are, for example, sliding bearings. - As shown in
FIGS. 3 to 5B etc., in the drivenroller 362 in the above support structure, thebearings 56 rotatably supporting therotating shaft 52 are attached to movable attachment members 72 disposed in thesupport members 70 so as to be movable by a given distance toward the drivingroller 361 as shown by double-pointed arrows E1-E2. - Each of the movable attachment members 72 includes a
support 73 that supports a corresponding bearing 5 for the drivenroller 362 movably with respect to therotating shaft 51 of the drivingroller 361. The supports 73 are attached and fixed to therespective support members 70. Thebearings 56 are, for example, sliding bearings. The supports 73 may be formed as portions of thesupport members 70 and integrated therewith. - In the driven
roller 362, thebearings 56 supporting therotating shaft 52 are supported by the movable attachment members 72 so as to be pressed by respective pressingmembers 57 in a direction E1 directed toward the rotatingshaft 51 of the drivingroller 361. - As described above, in the pair of
first output rollers 36, the driving roller 361 (the rotary member 5A) is rotatably supported by the support members 70 (their stationary attachment members 71) while the position of the drivingroller 361 is fixed. The driven roller 362 (the rotary member 5B) is rotatably supported by the supports 73 (the movable attachment members 72) of thesupport members 70 so as to be movable toward the drivingroller 361 and is also supported by thepressing members 57 through thebearings 56 so as to be pressed in the direction E1 directed toward the rotatingshaft 51 of the drivingroller 361. - In particular, as shown in
FIGS. 3, 4A, and 4C , in the pair offirst output rollers 36, the driven roller 362 (the rotary member 5B) employs a support structure 6 including: thebearings 56 that rotatably support the rotatingshaft 52; thepressing members 57 that press therespective bearings 56 in the direction E1 directed toward the rotatingshaft 51 of the drivingroller 361; and thesupports 73 that support therespective bearings 56 so as to be movable in the direction E1 in which thebearings 56 are pressed by the pressingmembers 57. - As shown in
FIGS. 4A and 4B , each of thebearings 56 in the support structure 6 includes a plate-shaped body 56 a having a substantially rectangular side portion. Each body 56 a includes: a bearinghole 56 b located at substantially the center and passing through the body 56 a; astep portion 56 c that is disposed in an upper outer portion of the body 56 a and extends in the moving direction E1-E2; and apressure receiving portion 56 d that receives the pressure of a corresponding pressingmember 57 on one side. - As shown in
FIGS. 4A and 4B , eachsupport 73 in the support structure 6 includes a body 74 having a holdingportion 74 a that accommodates a correspondingbearing 56 such that upper and lower portions of thebearing 56 are held so as to be movable in the direction E1-E2. The body 74 includes: alower guiding portion 74 b that holds and guides the lower side surface of thebearing 56 when it moves; anupper guiding portion 74 c that holds and guides the upper side surface (thestep portion 56 c) of thebearing 56 when it moves; and an abuttingportion 74 d against which part of the pressingmember 57 abuts to fix the pressingmember 57. - As shown in
FIGS. 4A and 4B , each of thepressing members 57 in the support structure 6 is composed of a member that can elastically press a correspondingbearing 56 in the direction E1 directed toward the rotatingshaft 51 of the drivingroller 361. Each of thepressing members 57 in exemplary embodiment 1 includes a coil spring. - Each of the coil springs of the
pressing members 57 is disposed between thepressure receiving portion 56 d of a correspondingbearing 56 and the abuttingportion 74 d of acorresponding support 73 and is used such that thebearing 56 is pressed by prescribed pressing force F toward the rotation center (02) of therotating shaft 52 of the drivenroller 362. - As shown in
FIG. 4A , in the abuttingportion 74 d of thesupport 73 in exemplary embodiment 1, aprotrusion holding portion 74 e that holds one end of the coil spring used as the pressingmember 57 is provided. Theprotrusion holding portion 74 e is fitted into an internal space at the one end of the coil, and the coil spring is thereby held. Since the one end of the coil spring is held by theprotrusion holding portion 74 e, the position of the coil spring is unlikely to be displaced. - <Problems with Support Structure for Pair of First Output Rollers>
- Generally, as exemplified in
FIG. 15A , in the support structure 6 for the drivenroller 362 of the pair offirst output rollers 36, each coil spring included in a corresponding pressingmember 57 is disposed such that its end portion opposite to the abuttingportion 74 d of acorresponding support 73 is pressed against part of a correspondingbearing 56. - The support structure 6 shown in
FIG. 15A is acomparative support structure 60. Both ends of the coil spring serving as the pressingmember 57 are assumed to be parallel to each other and have a substantially flat annular shape, unless otherwise specifically stated. Symbol L1 for a chain dashed line inFIG. 15A etc. represents a virtual straight line (virtual line) connecting therotation center 02 of the drivenroller 362 to therotation center 01 of the drivingroller 361. Symbol L2 for a chain dashed line represents the direction (the axial line) of therotating shaft 52 of the drivenroller 362. - In the
comparative support structure 60, the coil spring serving as the pressingmember 57 is disposed such that acentral portion 57 a of an end of the coil spring that is pressed against part of thebearing 56 substantially coincides with a position P1 at which the virtual line L1 intersects apressure receiving surface 56 e of thebearing 56 and is in contact with thepressure receiving surface 56 e.FIG. 15B shows aportion 57 b in which an end portion of the coil spring serving as the pressingmember 57 is in contact with thepressure receiving surface 56 e of thebearing 56 and also shows the state of theportion 57 b. In thissupport structure 60, the coil spring serving as the pressingmember 57 is attached on the assumption that the pressing force F of the coil spring acts toward therotation center 02 of therotating shaft 52. - As shown in
FIG. 15A , in thissupport structure 60, when the drivingroller 361 is rotated in a direction indicated by a chain double-dashed arrow at its operating timing, the drivenroller 362 is driven to rotate in a rotation direction C indicated by a chain double-dashed arrow. - In this case, as shown in
FIG. 15A , a rotational force (moment) Mr and a rotational drag force (moment) Mb are generated and act on thebearing 56. The rotational force Mr urges the bearing 56 to rotate in the rotation direction C through the frictional force such as the sliding force between the bearing 56 and therotating shaft 52 of the drivenroller 362. The rotational drag force Mb is caused by the pressingmember 57 pressed against thebearing 56 and urges the bearing 56 to rest against the rotational force Mr. - In fact, in the
support structure 60, the coil springs serving as thepressing members 57 may have different pressing characteristics (may have their own unique pressing characteristics) depending on the attachment states of the coil springs, their individual differences, etc. In this case, as shownFIGS. 16A and 16B , each bearing 56 may rotate about the rotatingshaft 52 and come to rest while in contact with part of the holdingportion 74 a of thesupport 73 and inclined within a movable space in thesupport 73. -
FIG. 16A shows a state (J1) in which thebearing 56 slides within the holdingportion 74 a of thesupport 73 in a direction opposite to the rotation direction C of the drivenroller 362 and is thereby inclined and at rest.FIG. 16B shows a state (J2) in which thebearing 56 slides within the holdingportion 74 a of thesupport 73 in the rotation direction C of the drivenroller 362 and is thereby inclined and at rest. - In this
support structure 60, during rotation of the drivenroller 362, the sliding friction between the bearing 56 and therotating shaft 52 may change instantaneously, and the rotational force Mr may increase or decrease. Specifically, when a reduction in the sliding friction occurs, the rotational force Mr decreases. In this case, the rotational force Mr can be substantially equal to the rotational drag force Mb (Mr≅Mb). - When these forces are substantially equal to each other, the
bearing 56 is unstable and can easily rotate about the rotatingshaft 52 during rotation of the drivenroller 362. Therefore, thebearing 56 rotates back and forth repeatedly between the above two states (J1 and J2). - Therefore, in the
support structure 60, the bearing 56 repeatedly collides with portions of thesupport 73, and this causes unwanted noise and vibration. When a transport device 7 is formed using thissupport structure 60, unwanted noise and vibration are generated during transfer of arecording paper sheet 9 by the transport device 7. - Accordingly, in exemplary embodiment 1, as the support structure 6 that supports the driven
roller 362 of the pair offirst output rollers 36, asupport structure 6A shown inFIGS. 4A and 5A is employed. In thesupport structure 6A, when the drivenroller 362 serving as the rotary member is not rotating, thebearing 56 and the pressingmember 57 are in contact with each other while thebearing 56 is rotatable about the rotatingshaft 52. - The state in which the
bearing 56 is rotatable is an unstable state. Specifically, for example, when the drivenroller 362 is not rotating, the bearing 56 can easily rotate about the rotatingshaft 52 in the rotation direction C of the driven roller 362 (or its rotating shaft 52) and also in a direction opposite to the rotation direction C, as shown inFIG. 6A . Symbol L1 for a chain dashed line inFIG. 6A represents a virtual line connecting therotation center 02 of the drivenroller 362 to therotation center 01 of the drivingroller 361, as does the virtual line L1 described above. - In the
support structure 6A for the drivenroller 362 in exemplary embodiment 1, each pressingmember 57 has aprotrusion 81, and theprotrusion 81 is in contact with a correspondingbearing 56. When the drivenroller 362 is not rotating, the bearing 56 can rotate about the rotatingshaft 52. - Moreover, in the
support structure 6A for the drivenroller 362, during rotation of the drivenroller 362, thebearing 56 is held in a state in which it is rotated in the rotation direction C of the drivenroller 362, as shown inFIG. 6B . - The phrase “the
bearing 56 is held in a state in which it is rotated in the rotation direction C of the drivenroller 362” means that, for example, the bearing 56 rotated in the rotation direction C of the drivenroller 362 comes into contact with part of the holdingportion 74 a of thesupport 73 and is thereby inclined and at rest and the inclined state is maintained during the rotation of the drivenroller 362, as shown inFIG. 6B . The phrase also encompasses the following case. - Specifically, during the rotation of the driven
roller 362 in the rotation direction C, thebearing 56 is brought to the inclined state described above. Then the bearing 56 in the inclined state slightly rotates continuously back and forth in the rotation direction C of the drivenroller 362 and its reverse rotation direction. In other words, in this state, during the rotation of the drivenroller 362 in the rotation direction C, thebearing 56 is prevented from rotating in the reverse rotation direction beyond the position at which thebearing 56 is unstable and rotatable when the drivenroller 362 is not rotating (FIG. 6A ). - The
protrusion 81 disposed in the pressingmember 57 is formed as a structural member having a spherical surface portion that comes in to contact with thepressure receiving surface 56 e of thepressure receiving portion 56 d of thebearing 56. - As shown in
FIG. 5B , theprotrusion 81 formed as the spherical surface-shaped structural member is in point contact with thepressure receiving surface 56 e of thepressure receiving portion 56 d of thebearing 56. This allows the bearing 56 to be easily rotatable when the drivenroller 362 is not rotating. -
Symbol 81 a inFIG. 5B represents a portion of theprotrusion 81 that is in contact with thebearing 56. Thecontact portion 81 a substantially corresponds to the apex of the spherical surface-shapedprotrusion 81. A chain dashed line L2 inFIG. 5B indicates the direction (axial line) of therotating shaft 52 of the drivenroller 362 as described above. - In fact, the term “point contact” also encompasses the case in which the shape of the
contact portion 81 a is a dot-like shape (a small circular shape) with a certain diameter (width) w1 on condition that shape of thecontact portion 81 a is maintained in the above-described rotatable state as shown inFIG. 5B . Thepressure receiving surface 56 e of thepressure receiving portion 56 d of thebearing 56 is a flat surface. However, thepressure receiving surface 56 e may be a curved surface with a small curvature so long as the point contact with theprotrusion 81 can be maintained. - As shown in
FIGS. 7A and 7B , the pressingmember 57 provided with theprotrusion 81 includes acoil spring 571 having afirst end 571 a to which acomponent 85 having theprotrusion 81 is attached. - The
component 85 having theprotrusion 81 has anattachment recess 85 c into which thefirst end 571 a of thecoil spring 571 is fitted. Theprotrusion 81 may be integrated with thecomponent 85, or theprotrusion 81 formed separately may be later integrated with thecomponent 85. - The pressing
member 57 provided with theprotrusion 81 is disposed such that theprotrusion 81 is pressed toward therotation center 02 of therotating shaft 52 of the drivenroller 362. Specifically, as shown inFIG. 6A , the pressingmember 57 is disposed such that its pressing force F acts toward therotation center 02 of therotating shaft 52. - In this case, the
coil spring 571 serving as the pressingmember 57 may be attached such that asecond end 571 b of thecoil spring 571 is fitted onto and held by theprotrusion holding portion 74 e (FIG. 4A ) provided in the abuttingportion 74 d of thesupport 73. - As shown in
FIGS. 5A and 6A , in thesupport structure 6A supporting the drivenroller 362 of the pair of first output rollers, when the drivenroller 362 is not rotating (is in a non-rotating state), thebearing 56 is in point contact with theprotrusion 81 disposed in the pressingmember 57. - In the
support structure 6A in this state, thebearing 56 is rotatable about the rotatingshaft 52 within the movable space in the holdingportion 74 a of thesupport 73. In this case, only the pressing force F exerted by the pressingmember 57 and directed to therotation center 02 of therotating shaft 52 acts on thebearing 56. Therefore, thebearing 56 is in an unstable state in which it can easily rotate about the rotatingshaft 52 in the rotation direction C of the drivenroller 362 and also in the reverse rotation direction. - As shown in
FIG. 6B , in thesupport structure 6A, when the drivenroller 362 is rotating during, for example, transportation of a recording paper sheet 9 (during rotation of the driven roller 362), the rotational force Mr in the rotation direction C of the drivenroller 362 acts on thebearing 56, as described above for thecomparative support structure 60. - Therefore, in the
support structure 6A, the bearing 56 that is rotatable when the drivenroller 362 is not rotating is maintained in a state in which thebearing 56 is rotated in the rotation direction C of the drivenroller 362 within the movable space in the holdingportion 74 a of thesupport 73. - Specifically, as shown in
FIG. 6B , the bearing 56 in this case is rotated in the rotation direction C of the drivenroller 362 within the movable space in the holdingportion 74 a of thesupport 73. Then part (a corner) of thebearing 56 comes into contact with part of the holdingportion 74 a, and thebearing 56 comes to rest, so that thebearing 56 is slightly inclined. - Also in this
support structure 6A, during rotation of the drivenroller 362, the sliding friction between the bearing 56 and therotating shaft 52 may change instantaneously, and the rotational force Mr may increase or decrease, as described above for thecomparative support structure 60. Specifically, when a reduction in the sliding friction occurs, the rotational force Mr decreases. In this case, the rotational force Mr and the rotational drag force Mb may become substantially equal to each other (Mr≅Mb). - However, in the
support structure 6A, theprotrusion 81 in the pressingmember 57 is in point contact with thebearing 56. Since the pressingmember 57 is disposed such that its pressing force F acts toward therotation center 02 of therotating shaft 52, the vector of the load generated by theprotrusion 81 is directed toward therotation center 02 of therotating shaft 52. Therefore, in thesupport structure 6A, the rotational drag force (moment) Mb itself that is caused by the pressingmember 57 pressed against thebearing 56 and urges the bearing 56 to rest against the rotational force Mr is unlikely to be generated. - Therefore, in the
support structure 6A, the rotational drag force Mb is unlikely to increase to a level comparable to the rotational force Mr, and the relation between the rotational force Mr and the rotational drag force Mb is easily maintained such that the rotational force Mr is larger than the rotational drag force Mb (Mr>Mb). - In this
support structure 6A, during rotation of the driven roller 362 (and the driving roller 361), thebearing 56 is easily maintained in a state in which it is rotated in the rotation direction C of the drivenroller 362 within the holdingportion 74 a of thesupport 73. In this case, thebearing 56 is prevented from rotating in the reverse rotation direction opposite to the rotation direction C beyond the position at which thebearing 56 is in the rotatable state when the drivenroller 362 is not rotating and from rotating back and forth repeatedly around the above position. - Therefore, in the
support structure 6A, generation of noise and vibration caused by repeated rotation of thebearing 56 within the movable space in thesupport 73 can be prevented or reduced, as described above for thecomparative support structure 60. - In the
support structure 6A, the generation of noise and vibration that occurs during rotation of the drivenroller 362 in thecomparative support structure 60 is prevented or reduced. Therefore, in a transport device 7 produced using thesupport structures 6A, arecording paper sheet 9 can be smoothly transported without generation of noise and vibration. - In the structural example shown in exemplary embodiment 1, the
protrusion 81 in point contact with thepressure receiving portion 56 d of thebearing 56 is a structural component having a spherical surface shape. However, this structural example is not a limitation. For example, theprotrusion 81 may be a structural component in which the portion in contact with thepressure receiving portion 56 d of thebearing 56 has a cone shape or a pyramid shape. - In the support structure 6 in which the
protrusion 81 in point contact with thebearing 56 is used, even when the drivenroller 362 is rotated in the rotation direction C and the reverse rotation direction in a switchable manner, thebearing 56 is rotated in the direction of rotation of the driven roller 362 (the rotation direction C or the reverse rotation direction). - In the
support structure 6A, even when the drivenroller 362 is rotated in the forward and reverse directions in a switchable manner, the generation of noise and vibration caused by repeated rotation of thebearing 56 as described above is prevented. -
FIGS. 8A and 8B show asupport structure 6B for the drivenroller 362 inexemplary embodiment 2. - The
support structure 6B according toexemplary embodiment 2 has the same structure as thesupport structure 6A according to exemplary embodiment 1 except that theprotrusion 81 is replaced with aprotrusion 82 having a different structure. Therefore, in thesupport structure 6B, the same components as thesupport structure 6A are denoted by the same symbols inFIGS. 8A and 8B and subsequent figures, and their description will be omitted in principle. - As shown in
FIGS. 8A and 8B , in thesupport structure 6B, the protrusion disposed in the pressingmember 57 is aprotrusion 82 in line contact along the axial line L2 of therotating shaft 52 with thepressure receiving surface 56 e of thepressure receiving portion 56 d of thebearing 56. Therefore, as shown inFIGS. 8A, 8B, and 9A , when the drivenroller 362 is not rotating, thebearing 56 is rotatable about the rotatingshaft 52. - Also in this
support structure 6B, as in thesupport structure 6A according to exemplary embodiment 1, during rotation of the drivenroller 362, thebearing 56 is held in a state in which it is rotated in the rotation direction C of the drivenroller 362, as shown inFIG. 9B . - The
protrusion 82 is formed as a structural component in which its portion coming into contact with thepressure receiving surface 56 e of thebearing 56 can be in line contact along the axial line L2 of therotating shaft 52. As shown inFIG. 10A , theprotrusion 82 is formed as, for example, a horizontally extending triangular prism-shaped structural component having anedge line 82 a that comes into contact with thebearing 56. - As shown in
FIG. 8B , theprotrusion 82 having the portion capable of line contact comes into line contact with thepressure receiving surface 56 e of thepressure receiving portion 56 d of thebearing 56. - In this case, when the driven
roller 362 is not rotating, the bearing 56 can be easily brought to the above-described rotatable state. When theprotrusion 82 in line contact along the axial line L2 of therotating shaft 52 is used, thebearing 56 is further prevented from being inclined accidentally in a direction intersecting the axial line L2, as compared to the case when theprotrusion 81 in point contact is used. Therefore, the posture of the bearing 56 in the direction of the axial line L2 is stabilized. - The term “line contact” encompasses the case in which the
contact portion 82 a of theprotrusion 82 has a continuous or discontinuous rectangular shape with a certain width w2 on condition that thebearing 56 is maintained in the above-described rotatable state, as shown inFIG. 8B . In this case, the width w2 is shorter than the length k1 of thecontact portion 82 a along the axial line L2 of the rotating shaft 52 (w2<k1). - The pressing
member 57 provided with theprotrusion 82 includes acoil spring 571 having an end to which acomponent 85 having theprotrusion 82 is attached (e.g.,FIG. 8A ), as is the pressingmember 57 provided with the protrusion 81 (FIGS. 7A and 7B ). - As shown in
FIGS. 8A, 8B, and 9A , in thesupport structure 6B supporting the drivenroller 362, when the drivenroller 362 is not rotating, thebearing 56 is in line-contact with theprotrusion 82 in the pressingmember 57. - In the
support structure 6B in this case, as in thesupport structure 6A, thebearing 56 is rotatable about the rotatingshaft 52 within the movable space in the holdingportion 74 a of thesupport 73. In this case, thebearing 56 is in an unstable state in which it can easily rotate in the rotation direction C of the drivenroller 362 and also in the reverse rotation direction. However, the posture of thebearings 56 along the axial line L2 of therotating shaft 52 is in a stable state. - As shown in
FIG. 9B , in thesupport structure 6B, when the drivenroller 362 is rotating, the rotational force Mr in the rotation direction C of the drivenroller 362 acts on thebearing 56, and therefore thebearing 56 is held in a state in which it is rotated in the rotation direction C of the drivenroller 362 within the movable space in the holdingportion 74 a of thesupport 73. - Specifically, as shown in
FIG. 9B , the bearing 56 in this case is rotated in the rotation direction C of the drivenroller 362 within the movable space in the holdingportion 74 a of thesupport 73. Then part (a corner) of thebearing 56 comes into contact with part of the holdingportion 74 a, and thebearing 56 comes to rest, so that thebearing 56 is slightly inclined. - In this the
support structure 6B, as in thesupport structure 6A, during rotation of the drivenroller 362, the sliding friction between the bearing 56 and therotating shaft 52 may change instantaneously, and the rotational force Mr may increase or decrease. For example, the rotational force Mr and the rotational drag force Mb may become substantially equal to each other (Mr≅Mb). - However, in the
support structure 6B, theprotrusion 82 in the pressingmember 57 is in line contact with thebearing 56. Since the pressingmember 57 is disposed such that its pressing force F acts toward therotation center 02 of therotating shaft 52, the vector of the load generated by theprotrusion 82 is directed toward therotation center 02 of therotating shaft 52. Therefore, in thesupport structure 6B, as in thesupport structure 6A, the rotational drag force Mb itself that is caused by the pressingmember 57 pressed against thebearing 56 and urges the bearing 56 to rest against the rotational force Mr is unlikely to be generated. - Therefore, also in the
support structure 6B, as in thesupport structure 6A, the rotational drag force Mb is unlikely to increase to a level comparable to the rotational force Mr, and the relation between the rotational force Mr and the rotational drag force Mb is easily maintained such that the rotational force Mr is larger than the rotational drag force Mb (Mr>Mb). - Also in this
support structure 6B, during rotation of the drivenroller 362, thebearing 56 is easily maintained in a state in which it is rotated in the rotation direction C of the drivenroller 362 within the holdingportion 74 a of thesupport 73. In this case, thebearing 56 is prevented from rotating in the reverse rotation direction opposite to the rotation direction C beyond the position at which thebearing 56 is in the rotatable state when the drivenroller 362 is not rotating and from rotating back and forth repeatedly around the above position. - Therefore, also in this
support structure 6B, as in thesupport structure 6A, generation of noise and vibration caused by repeated rotation of thebearing 56 within the movable space in thesupport 73 can be prevented or reduced. - In
exemplary embodiment 2, theprotrusion 82 in line contact may be, for example, a structural body including a semicylindrical member having an apex portion (ridge line) 82 b extending substantially linearly in a lengthwise direction, as shown inFIG. 10B . This structural body may be disposed such that theapex portion 82 b comes into contact with thebearing 56. - In this case, the
apex portion 82 b of theprotrusion 82 is less worn due to contact with the bearing 56 than theprotrusion 82 of the structural body shown inFIG. 10A , and thebearing 56 can be maintained in a desirable state for a long time. -
FIG. 11 shows asupport structure 6C for the drivenroller 362 inexemplary embodiment 3. - The
support structure 6C according toexemplary embodiment 3 has the same structure as thesupport structure 6A according to exemplary embodiment 1 except that theprotrusion 81 is disposed in thebearing 56. Therefore, in thesupport structure 6C, the same components as thesupport structure 6A are denoted by the same symbols inFIGS. 11A and 11B and subsequent figures, and their description will be omitted in principle. - In the
support structure 6C, the protrusion disposed in thebearing 56 is aprotrusion 83 that comes into point contact with one end of a coil spring serving as the pressingmember 57, as shown inFIGS. 11A and 11B . Therefore, as shown inFIGS. 11A, 11B, and 12A , when the drivenroller 362 is not rotating, thebearing 56 is rotatable about the rotatingshaft 52. - Also in this
support structure 6C, as in thesupport structure 6A according to exemplary embodiment 1, during rotation of the drivenroller 362, thebearing 56 is held in a state in which it is rotated in the rotation direction C of the drivenroller 362, as shown inFIG. 12B . - The
protrusion 83 disposed in thebearing 56 is formed as a structural component in which its portion coming into contact with one end of the pressingmember 57 has a spherical surface shape, as is theprotrusion 81 in thesupport structure 6A. In this case, the pressingmember 57 is formed as, for example, acoil spring 571 to which acomponent 85 having a flat surface serving as aportion 85 a to be in contact with theprotrusion 83 is attached to the one end. - As shown in
FIG. 11B , theprotrusion 83 formed as the spherical surface-shaped structural body comes into point contact with the one end of thecoil spring 571 serving as the pressing member 57 (theflat portion 85 a of the component 85). In this manner, when the drivenroller 362 is not rotating, the bearing 56 can be easily brought to the above-described rotatable state. -
Symbol 83 a inFIG. 11B represents a portion of theprotrusion 83 that is in contact with the one end of thecoil spring 571 serving as the pressingmember 57. Thecontact portion 83 a substantially corresponds to the apex of the spherical surface-shapedprotrusion 83. - In the
support structure 6C, as in thesupport structure 6A, the pressingmember 57 is disposed so as to be pressed toward therotation center 02 of therotating shaft 52 of the drivenroller 362. Specifically, as shown inFIG. 12A , the pressingmember 57 is disposed such that its pressing force F acts toward therotation center 02 of therotating shaft 52. - As shown in
FIGS. 11A, 11B, and 12A , in thissupport structure 6C, when the drivenroller 362 is not rotating, theprotrusion 83 disposed in thebearing 56 is in point contact with the one end of the pressingmember 57. - In the
support structure 6C in this case, substantially as in thesupport structure 6A, thebearing 56 is rotatable about the rotatingshaft 52 within the movable space in the holdingportion 74 a of thesupport 73. In this case, thebearing 56 is in an unstable state in which it can easily rotate in the rotation direction C of the drivenroller 362 and also in the reverse rotation direction. However, the posture of thebearing 56 along the axial line L2 of therotating shaft 52 is in a stable state. - As shown in
FIG. 12B , in thesupport structure 6C, when the drivenroller 362 is rotating, the rotational force Mr in the rotation direction C of the drivenroller 362 acts on thebearing 56. Therefore, thebearings 56 is held in a state in which it is rotatable in the rotation direction C of the drivenroller 362 within the movable space in the holdingportion 74 a of thesupport 73. - Specifically, as shown in
FIG. 12B , the bearing 56 in this case is rotated in the rotation direction C of the drivenroller 362 within the movable space in the holdingportion 74 a of thesupport 73. Then part (a corner) of thebearing 56 comes into contact with part of the holdingportion 74 a, and thebearing 56 comes to rest, so that thebearing 56 is slightly inclined. - In the
support structure 6C, as in thesupport structure 6A etc., during rotation of the drivenroller 362, the sliding friction between the bearing 56 and therotating shaft 52 may change instantaneously, and the rotational force Mr may increase or decrease. Therefore, for example, the rotational force Mr and the rotational drag force Mb may become substantially equal to each other (Mr≅Mb). - However, in this
support structure 6C, theprotrusion 83 in thebearing 56 is in point contact with the pressingmember 57. Since the pressingmember 57 is disposed such that its pressing force F acts toward therotation center 02 of therotating shaft 52, the vector of the load generated by theprotrusion 83 is directed toward therotation center 02 of therotating shaft 52. Therefore, in thesupport structure 6C, the rotational drag force Mb itself that is caused by the pressingmember 57 pressed against thebearing 56 and acts against the rotational force Mr is unlikely to be generated. - Therefore, also in the
support structure 6C, because of substantially the same reason as in thesupport structure 6A etc., the rotational drag force Mb is unlikely to increase to a level comparable to the rotational force Mr, and the relation between the rotational force Mr and the rotational drag force Mb is easily maintained such that the rotational force Mr is larger than the rotational drag force Mb (Mr>Mb). - Also in this
support structure 6C, during rotation of the drivenroller 362, thebearing 56 is easily maintained in a state in which it is rotated in the rotation direction C of the drivenroller 362 within the holdingportion 74 a of thesupport 73. In this case, thebearing 56 is prevented from rotating in the reverse rotation direction opposite to the rotation direction C beyond the position at which thebearing 56 is in the rotatable state when the drivenroller 362 is not rotating and from rotating back and forth repeatedly around the above position. - Therefore, also in the
support structure 6C, substantially as in thesupport structure 6A, generation of noise and vibration caused by repeated rotation of thebearing 56 within the movable space in thesupport 73 can be prevented or reduced. - In
exemplary embodiment 3, theprotrusion 83 in point contact may be, for example, a different structural member such as that described in exemplary embodiment 1. - In
exemplary embodiment 3, theprotrusion 82 in line contact as exemplified inexemplary embodiment 2 may be used instead of theprotrusion 83 in point contact. -
FIG. 13 shows asupport structure 6D for a chargingroller 220 inexemplary embodiment 4 and the chargingdevice 22 using thesupport structure 6D. - This
support structure 6D supports the chargingroller 220 in the chargingdevice 22 of theimage forming unit 2. For example, thesupport structure 6A according to exemplary embodiment 1 (FIGS. 4A, 4B, 5A, 5B , etc.) is used as thesupport structure 6D. - The charging
roller 220 is a rotary member 5C including, for example: a rotatingshaft 221 to which a charging voltage is supplied; and aroller body 222 disposed on therotating shaft 221 and having a multilayer structure including an elastic layer, a surface layer, etc. The chargingroller 220 is in contact with the circumferential surface of thephotoreceptor drum 21 rotating in the direction of arrow A and is driven to rotate by thephotoreceptor drum 21 in a direction indicated by chain double-dashed arrow D, and the circumferential surface of thephotoreceptor drum 21 is thereby charged. - A chain dashed line L3 in
FIG. 13 etc. represents a virtual straight line (virtual line) connecting therotation center 03 of thephotoreceptor drum 21 to therotation center 04 of the chargingroller 220. A double-pointed arrow denoted by symbols E3 and E4 indicates moving directions when thesupport 73 movably supports the bearing 56 of the chargingroller 220. - As shown in
FIG. 13 , in thesupport structure 6D supporting the chargingroller 220, substantially as in thesupport structure 6A according to exemplary embodiment 1, theprotrusion 81 disposed in the pressingmember 57 is in point contact with thepressure receiving surface 56 e of thepressure receiving portion 56 d of the bearing 56 (see, for example,FIG. 6B ). In this case, as shown inFIG. 14A , when the chargingroller 220 is not rotating, thebearing 56 is rotatable about therotating shaft 221. - As shown in
FIG. 14B , also in thissupport structure 6D, substantially as in thesupport structure 6A according to exemplary embodiment 1, when the chargingroller 220 is rotating, thebearing 56 is maintained in a state in which it is rotated in the rotation direction D of the chargingroller 220. - As shown in
FIGS. 13 and 14A , in thesupport structure 6D for the chargingroller 220, when the chargingroller 220 is not rotating, thebearing 56 is in point contact with theprotrusion 81 disposed in the pressingmember 57. - In the
support structure 6D in this case, as in thesupport structure 6A, thebearing 56 is rotatable about therotating shaft 221 within the movable space in the holdingportion 74 a of thesupport 73. - As shown in
FIG. 14B , in thesupport structure 6D, when the chargingroller 220 is rotating, the rotational force Mr in the rotation direction D of the chargingroller 220 acts on thebearing 56. Therefore, thebearing 56 is held in a state in which it is rotatable in the rotation direction D within the movable space in the holdingportion 74 a of thesupport 73. - Specifically, as shown in
FIG. 14B , the bearing 56 in this case is rotated in the rotation direction D of the chargingroller 220 within the movable space in the holdingportion 74 a of thesupport 73. Then part (a corner) of thebearing 56 comes into contact with part of the holdingportion 74 a, and thebearing 56 comes to rest, so that thebearing 56 is slightly inclined. - Also in the
support structure 6D, as in thesupport structure 6A, during rotation of the chargingroller 220, the sliding friction between the bearing 56 and therotating shaft 221 may change instantaneously, and the rotational force Mr may increase or decrease. For example, the rotational force Mr and the rotational drag force Mb may become substantially equal to each other (Mr≅Mb). - However, in the
support structure 6D, because of the same reason as in thesupport structure 6A, the rotational drag force Mb is unlikely to increase to a level comparable to the rotational force Mr, and the relation between the rotational force Mr and the rotational drag force Mb is easily maintained such that the rotational force Mr is larger than the rotational drag force Mb (Mr>Mb). - Also in this
support structure 6D, during rotation of the chargingroller 220, thebearing 56 is easily maintained in a state in which it is rotated in the rotation direction D of the chargingroller 220 within the holdingportion 74 a of thesupport 73. In this case, thebearing 56 is prevented from rotating in the reverse rotation direction opposite to the rotation direction C beyond the position at which thebearing 56 is in the rotatable state when the chargingroller 220 is not rotating and from rotating back and forth repeatedly around the above position. - Therefore, also in the
support structure 6D, as in thesupport structure 6A, generation of noise and vibration caused by repeated rotation of thebearing 56 within the movable space in thesupport 73 can be prevented or reduced. - In the
support structure 6D, the generation of noise and vibration during rotation of the chargingroller 220 is prevented or reduced. Therefore, in the chargingdevice 22 formed using thesupport structure 6D, charging can be performed desirably without generation of noise and vibration. - In the structural examples shown in exemplary embodiments 1 to 3, one of the
support structures 6A to 6C is used as the structure for supporting the driven roller 362 (the rotary member 5B) of the pair offirst output rollers 36. However, any of them may be used as a structure for supporting the driving roller 361 (the rotary member 5A) of the pair offirst output rollers 36. - In the pair of
first output rollers 36, the drivingroller 361 may be replaced with an elastic roller having the function of correcting curl of arecording paper sheet 9. The elastic roller is, for example, a continuous single roller such as the drivenroller 362, and an elastic body is used as its roller body. - Each of the
support structures 6A to 6C exemplified in exemplary embodiments 1 to 3 can be used for a transport device including a pair of transport rollers (rotary members) that are in pressure contact with each other and are rotated and transport arecording paper sheet 9 held therebetween. Specifically, each of thesupport structures 6A to 6C can be used as a support structure for at least one of the pair of transport rollers. - Each of the
support structure 6A to 6C exemplified in exemplary embodiments 1 to 3 can be used as thesupport structure 6D for the chargingroller 220 in the chargingdevice 22 of theimage forming unit 2 exemplified inexemplary embodiment 4, but this is not a limitation. Each of thesupport structures 6A to 6C may be used as the support structure for a different rotary member. Examples of such a rotary member include a transfer roller and fixing roller. - Each of the
support structures 6A to 6C may be used as the support structure for a pressing roller pressed against a portion of an endless belt that is not supported by a support roller. In this case, a rotary member in contact with the pressing roller is a portion of the rotating belt that is not supported by the support roller. - Moreover, an image forming apparatus including the rotary member using one of the
support structures 6A to 6D and the transport device 7 or the chargingdevice 22 is not limited to the apparatus forming a monochrome image using a single-color toner as exemplified in exemplary embodiments 1 to 4. Image forming apparatuses of different types may be used. - Examples of the image forming apparatuses of different types include: an image forming apparatus that forms a multicolor image using a combination of plural color toners; and an image forming apparatus that forms an image by jetting ink droplets.
- The rotary member and the transport device 7 that use any of the
support structures 6A to 6C may be a rotary member and a transport device of an apparatus other than the image forming apparatus. - The foregoing description of the exemplary embodiments of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in the art. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to understand the invention for various embodiments and with the various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents.
Claims (15)
1. A rotary member support structure comprising:
a rotary member including a shaft;
a bearing that rotatably supports the shaft of the rotary member;
a pressing member that presses the bearing in one direction; and
a support that supports the bearing such that the bearing is movable in a pressing direction of the pressing member,
wherein, when the rotary member is not rotating, the bearing and the pressing member are in contact with each other such that the bearing is rotatable about the shaft.
2. A rotary member support structure comprising:
a rotary member including a shaft;
a bearing that rotatably supports the shaft of the rotary member;
a pressing member that presses the bearing in one direction; and
a support that supports the bearing such that the bearing is movable in a pressing direction of the pressing member,
wherein a first one of the bearing and the pressing member has a protrusion, and a second one of the bearing and the pressing member is in contact with the protrusion,
and wherein, when the rotary member is not rotating, the bearing is rotatable about the shaft.
3. The rotary member support structure according to claim 1 , wherein, during rotation of the rotary member, the bearing is maintained in a state in which the bearing is rotatable in a rotation direction of the rotary member.
4. The rotary member support structure according to claim 2 , wherein, during rotation of the rotary member, the bearing is maintained in a state in which the bearing is rotatable in a rotation direction of the rotary member.
5. The rotary member support structure according to claim 1 , wherein the pressing member is disposed so as to press the bearing toward the rotation center of the shaft of the rotary member.
6. The rotary member support structure according to claim 2 , wherein the pressing member is disposed so as to press the bearing toward the rotation center of the shaft of the rotary member.
7. The rotary member support structure according to claim 1 , wherein the bearing and the pressing member are in point contact with each other or in line contact with each other along an axial line of the shaft.
8. The rotary member support structure according to claim 2 , wherein the protrusion and the second one of the bearing and the pressing member are in point contact with each other or in line contact with each other along an axial line of the shaft.
9. The rotary member support structure according to claim 2 , wherein the protrusion is disposed in the pressing member.
10. The rotary member support structure according to claim 9 , wherein the pressing member is a coil spring in which a component having the protrusion is attached to one end thereof.
11. A transport device comprising:
a pair of transport rotary members that transport a transportation object held therebetween; and
the rotary member support structure according to claim 1 , the rotary member support structure supporting at least one of the pair of transport rotary members.
12. A charging device comprising:
a charging rotary member; and
the rotary member support structure according to claim 1 , the rotary member support structure supporting the charging rotary member.
13. An image forming apparatus comprising the rotary member support structure according to claim 1 .
14. An image forming apparatus comprising the transport device according to claim 11 .
15. An image forming apparatus comprising the charging device according to claim 12 .
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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JP2017-233292 | 2017-12-05 | ||
JP2017233292A JP2019100478A (en) | 2017-12-05 | 2017-12-05 | Support structure of rotary part, conveyance device, charge device and image forming device |
Publications (1)
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US20190168978A1 true US20190168978A1 (en) | 2019-06-06 |
Family
ID=66658822
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US16/109,792 Abandoned US20190168978A1 (en) | 2017-12-05 | 2018-08-23 | Rotary member support structure, transport device, charging device, and image forming apparatus |
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US (1) | US20190168978A1 (en) |
JP (1) | JP2019100478A (en) |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
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US4850584A (en) * | 1985-07-15 | 1989-07-25 | Mita Industrial Co., Ltd. | Bearing arrangement in sheet member feed apparatus for use in electrophotographic copying machine |
US5351945A (en) * | 1992-05-30 | 1994-10-04 | Mita Industrial Co., Ltd. | Overlapped transfer-preventing mechanism |
US7731189B2 (en) * | 2007-09-28 | 2010-06-08 | Teco Image Systems Co., Ltd. | Paper guide adjusting mechanism and office machine using such mechanism |
US8998206B2 (en) * | 2010-07-05 | 2015-04-07 | Nidec Sankyo Corporation | Medium feeding direction switching mechanism and medium issuing and collecting device |
US20160070194A1 (en) * | 2010-12-20 | 2016-03-10 | Canon Kabushiki Kaisha | Image forming apparatus |
US20160266522A1 (en) * | 2015-03-09 | 2016-09-15 | Kyocera Document Solutions Inc. | Image forming apparatus capable of preventing displacement of transfer unit |
-
2017
- 2017-12-05 JP JP2017233292A patent/JP2019100478A/en active Pending
-
2018
- 2018-08-23 US US16/109,792 patent/US20190168978A1/en not_active Abandoned
Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4850584A (en) * | 1985-07-15 | 1989-07-25 | Mita Industrial Co., Ltd. | Bearing arrangement in sheet member feed apparatus for use in electrophotographic copying machine |
US5351945A (en) * | 1992-05-30 | 1994-10-04 | Mita Industrial Co., Ltd. | Overlapped transfer-preventing mechanism |
US7731189B2 (en) * | 2007-09-28 | 2010-06-08 | Teco Image Systems Co., Ltd. | Paper guide adjusting mechanism and office machine using such mechanism |
US8998206B2 (en) * | 2010-07-05 | 2015-04-07 | Nidec Sankyo Corporation | Medium feeding direction switching mechanism and medium issuing and collecting device |
US20160070194A1 (en) * | 2010-12-20 | 2016-03-10 | Canon Kabushiki Kaisha | Image forming apparatus |
US9501000B2 (en) * | 2010-12-20 | 2016-11-22 | Canon Kabushiki Kaisha | Image forming apparatus |
US20160266522A1 (en) * | 2015-03-09 | 2016-09-15 | Kyocera Document Solutions Inc. | Image forming apparatus capable of preventing displacement of transfer unit |
US9690237B2 (en) * | 2015-03-09 | 2017-06-27 | Kyocera Document Solutions Inc. | Image forming apparatus capable of preventing displacement of transfer unit |
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JP2019100478A (en) | 2019-06-24 |
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