EP0651300B1 - Image forming apparatus - Google Patents
Image forming apparatus Download PDFInfo
- Publication number
- EP0651300B1 EP0651300B1 EP95100526A EP95100526A EP0651300B1 EP 0651300 B1 EP0651300 B1 EP 0651300B1 EP 95100526 A EP95100526 A EP 95100526A EP 95100526 A EP95100526 A EP 95100526A EP 0651300 B1 EP0651300 B1 EP 0651300B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- cartridge
- shaft
- drum
- image
- transfer
- 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.)
- Expired - Lifetime
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Classifications
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- 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
- G03G21/18—Mechanical means for facilitating the maintenance of the apparatus, e.g. modular arrangements using a processing cartridge, whereby the process cartridge comprises at least two image processing means in a single unit
- G03G21/1839—Means for handling the process cartridge in the apparatus body
- G03G21/1842—Means for handling the process cartridge in the apparatus body for guiding and mounting the process cartridge, positioning, alignment, locks
- G03G21/1853—Means for handling the process cartridge in the apparatus body for guiding and mounting the process cartridge, positioning, alignment, locks the process cartridge being mounted perpendicular to the axis of the photosensitive member
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- 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
- G03G15/01—Apparatus for electrographic processes using a charge pattern for producing multicoloured copies
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- 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
- G03G15/01—Apparatus for electrographic processes using a charge pattern for producing multicoloured copies
- G03G15/0105—Details of unit
- G03G15/0131—Details of unit for transferring a pattern to a second base
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- 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
- G03G15/14—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base
- G03G15/16—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base of a toner pattern, e.g. a powder pattern, e.g. magnetic transfer
- G03G15/1605—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base of a toner pattern, e.g. a powder pattern, e.g. magnetic transfer using at least one intermediate support
- G03G15/1615—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base of a toner pattern, e.g. a powder pattern, e.g. magnetic transfer using at least one intermediate support relating to the driving mechanism for the intermediate support, e.g. gears, couplings, belt tensioning
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- 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
- G03G15/14—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base
- G03G15/16—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base of a toner pattern, e.g. a powder pattern, e.g. magnetic transfer
- G03G15/1665—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base of a toner pattern, e.g. a powder pattern, e.g. magnetic transfer by introducing the second base in the nip formed by the recording member and at least one transfer member, e.g. in combination with bias or heat
- G03G15/167—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base of a toner pattern, e.g. a powder pattern, e.g. magnetic transfer by introducing the second base in the nip formed by the recording member and at least one transfer member, e.g. in combination with bias or heat at least one of the recording member or the transfer member being rotatable during the transfer
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- 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
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- 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
- G03G21/1661—Mechanical means for facilitating the maintenance of the apparatus, e.g. modular arrangements means for handling parts of the apparatus in the apparatus
- G03G21/168—Mechanical means for facilitating the maintenance of the apparatus, e.g. modular arrangements means for handling parts of the apparatus in the apparatus for the transfer unit
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- 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
- G03G21/18—Mechanical means for facilitating the maintenance of the apparatus, e.g. modular arrangements using a processing cartridge, whereby the process cartridge comprises at least two image processing means in a single unit
- G03G21/1839—Means for handling the process cartridge in the apparatus body
- G03G21/1857—Means for handling the process cartridge in the apparatus body for transmitting mechanical drive power to the process cartridge, drive mechanisms, gears, couplings, braking mechanisms
- G03G21/1864—Means for handling the process cartridge in the apparatus body for transmitting mechanical drive power to the process cartridge, drive mechanisms, gears, couplings, braking mechanisms associated with a positioning function
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G2215/00—Apparatus for electrophotographic processes
- G03G2215/01—Apparatus for electrophotographic processes for producing multicoloured copies
- G03G2215/0167—Apparatus for electrophotographic processes for producing multicoloured copies single electrographic recording member
- G03G2215/0174—Apparatus for electrophotographic processes for producing multicoloured copies single electrographic recording member plural rotations of recording member to produce multicoloured copy
- G03G2215/018—Linearly moving set of developing units, one at a time adjacent the recording member
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G2221/00—Processes not provided for by group G03G2215/00, e.g. cleaning or residual charge elimination
- G03G2221/16—Mechanical means for facilitating the maintenance of the apparatus, e.g. modular arrangements and complete machine concepts
- G03G2221/1603—Mechanical means for facilitating the maintenance of the apparatus, e.g. modular arrangements and complete machine concepts for multicoloured copies
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G2221/00—Processes not provided for by group G03G2215/00, e.g. cleaning or residual charge elimination
- G03G2221/16—Mechanical means for facilitating the maintenance of the apparatus, e.g. modular arrangements and complete machine concepts
- G03G2221/1642—Mechanical means for facilitating the maintenance of the apparatus, e.g. modular arrangements and complete machine concepts for the transfer unit
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G2221/00—Processes not provided for by group G03G2215/00, e.g. cleaning or residual charge elimination
- G03G2221/16—Mechanical means for facilitating the maintenance of the apparatus, e.g. modular arrangements and complete machine concepts
- G03G2221/1651—Mechanical means for facilitating the maintenance of the apparatus, e.g. modular arrangements and complete machine concepts for connecting the different parts
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G2221/00—Processes not provided for by group G03G2215/00, e.g. cleaning or residual charge elimination
- G03G2221/16—Mechanical means for facilitating the maintenance of the apparatus, e.g. modular arrangements and complete machine concepts
- G03G2221/1651—Mechanical means for facilitating the maintenance of the apparatus, e.g. modular arrangements and complete machine concepts for connecting the different parts
- G03G2221/1654—Locks and means for positioning or alignment
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G2221/00—Processes not provided for by group G03G2215/00, e.g. cleaning or residual charge elimination
- G03G2221/16—Mechanical means for facilitating the maintenance of the apparatus, e.g. modular arrangements and complete machine concepts
- G03G2221/1651—Mechanical means for facilitating the maintenance of the apparatus, e.g. modular arrangements and complete machine concepts for connecting the different parts
- G03G2221/1657—Mechanical means for facilitating the maintenance of the apparatus, e.g. modular arrangements and complete machine concepts for connecting the different parts transmitting mechanical drive power
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G2221/00—Processes not provided for by group G03G2215/00, e.g. cleaning or residual charge elimination
- G03G2221/16—Mechanical means for facilitating the maintenance of the apparatus, e.g. modular arrangements and complete machine concepts
- G03G2221/18—Cartridge systems
- G03G2221/183—Process cartridge
Definitions
- the cartridge includes both a charging mechanism for charging the drum and a cleaning mechanism for cleaning it.
- An access opening is provided for imagewise exposure of a charged surface of the drum to create an electrostatic image on the drum.
- the electrostatic image is toned through another access opening in the cartridge by one of two toning stations which are rotatable into position opposite the access opening to create a toner image.
- the toner image is transferred to a receiving sheet fed through a receiving sheet opening into contact with the drum.
- the receiving sheet is separated from the drum by a special mechanism which is part of the cartridge and fed outside of the cartridge to a fusing device.
- An access opening to the drum permits transfer of toner images to a receiving sheet fed into engagement with the drum.
- Rotation of the drum is accomplished by a driving connection at the end of the cartridge which must mate with a drive member in the receiving apparatus. Projections are provided on the cartridge to prevent damage to the cartridge driving connection member from careless handling.
- an image forming apparatus which includes a replaceable cartridge supporting an image member.
- the cartridge includes an access opening for transfer of toner images from the image member to a transfer surface.
- the image forming apparatus includes a transfer member not part of the cartridge and having a transfer surface associated with it for receiving toner images from the image member.
- the cartridge is urged toward the transfer member to urge the image member into transfer engagement with the transfer surface.
- Control structure associated with the transfer member engages the cartridge to accurately position the image member with respect to the transfer member.
- the image member is drum-shaped, having a cylindrical outer image surface upon which toner images are formed as the image member rotates about an axis of rotation.
- the transfer member is a transfer drum also having an axis of rotation and a cylindrical outer surface.
- the image forming apparatus includes means for controlling the relative positions of the axes of rotation of the transfer member and the image member to maintain them parallel. Maintenance of parallelism between the axes of rotation of the image member and transfer member prevents image degradation during transfer.
- Fig. 1 is a perspective schematic of an image forming apparatus with housing and other support parts eliminated for clarity of illustration.
- Fig. 2 is a perspective view illustrating the drive train of an image forming apparatus with some parts in phantom and other parts eliminated for clarity of illustration.
- Fig. 3 is a front schematic of the image forming apparatus shown in Fig. 1 with portions of an image member cartridge shown in cross section for clarity of illustration.
- Fig. 4 is a front schematic of the drive train and cartridge portions of the image forming apparatus with portions eliminated and broken away for clarity of illustration.
- Fig. 5 is a perspective view of a cartridge and a mounting structure portion of an alternative image forming apparatus.
- Fig. 6 is a perspective view of an over-center spring mechanism forming a part of the apparatus shown in Fig. 5.
- Figs. 7 and 8 are front views of the structure shown in Fig. 5 in its partially loaded and fully loaded conditions, respectively.
- Figs. 9 and 10 are rear views of the structure shown in Figs. 7 and 8 also in its partially loaded and fully loaded conditions, respectively.
- Figs. 11 and 12 are top views of the structure shown in Figs. 5-10 in its partially loaded and fully loaded conditions, respectively.
- Figs. 13 and 14 are front and rear views, respectively, of a circular disk which forms part of a knob 121 shown in Figs. 5 and 6.
- Fig. 15 is a top section of a transfer drum illustrating an alternative drive mechanism for the apparatus shown in Fig. 1.
- Printer 1 includes an image member, for example, a photoconductive drum 2 which is rotatable through a series of stations for forming a series of toner images of different colors.
- Photoconductive drum 2 has a cylindrical image surface which is first charged by a charging station 4 and then imagewise exposed by a laser 5 to create a series of electrostatic images.
- the electrostatic images are toned by toners of different color by a movable development device 6 which includes 3 or 4 separate development units. Each unit applies a different color toner to one of the series of electrostatic images to create a series of different color toner images on the cylindrical image surface of drum 2.
- the series of different color toner images are transferred in registration to a transfer surface associated with a transfer drum 10 to create a multicolor color image on that surface.
- a transfer surface associated with a transfer drum 10 As shown in Fig. 1, the surface to which the toner images are transferred is a cylindrical peripheral surface of drum 10 itself. However, the toner images could also be transferred to a receiving sheet held on the surface of drum 10 as is well known in the art.
- the multicolor image is transferred by a transfer station 21 to a receiving sheet fed from a receiving sheet supply 45.
- the receiving sheet is then transported to a fuser 23 where the multicolor image is fixed and then to an output hopper 44 through an inverting path.
- the transfer surface of the transfer drum 10 is cleaned by an articulating cleaner 30 so that it may receive a new set of images.
- the photoconductive drum 2 is cleaned continuously during image formation by a cleaning device 12.
- the photoconductive drum 2 is supplied to the printer 1 in a cartridge 3 which cartridge may also contain other portions of printer 1.
- the cartridge may contain the charging device 4, the developing device 6 and/or cleaning devices 30 and 12.
- a cartridge housing contains image member 2, an opening for exposure by laser 5, charging device 4 and image member cleaning device 12. It also includes a sump 11 for receiving toner cleaned by cleaning device 12 off image member 2 and a sump 35 for receiving toner cleaned off transfer drum 10 by transfer drum cleaner 30.
- the housing also includes an opening 7 providing access to image member 2 for development device 6 and an opening 9 providing access to image member 2 for transfer drum 10.
- Articulating cleaner 30 is moved in and out of engagement with transfer drum 10 by a solenoid 31. It includes a cleaning roller which rolls on the surface of transfer drum 10 which roller is biased and formed of a material which encourages removal of toner to the roller. Cleaned toner is scraped off the roller by a scraping blade 32. An opening 36 in the cartridge housing receives scraped toner into sump 35.
- a receiving sheet is fed from a receiving sheet supply 20 into transfer relation with transfer drum 10.
- transfer is accomplished by a corona transfer station 21, known in the art.
- the transfer sheet is picked off transfer drum 10 by a movable pick-off 22 which also directs the transfer sheet to fuser 23.
- FIG. 2 is a perspective drawing illustrating the drive train from motor 42 through transfer drum 10 and photoconductive drum 2.
- engagement as used herein with reference to the image member and the transfer member is preferably direct contacting engagement of those members. However, although not preferred, it can also be engagement through a receiving sheet carried by the transfer member.
- transfer drum 10 is shown with an external drive engagement between transfer drum 10 and motor 42, motor 42 could be positioned inside transfer drum 10 and internally engaged with drum 10 to save space in printer 1. This latter embodiment is shown in Fig. 15.
- transfer drum 10 includes an outer layer 201 of polyurethane cast or otherwise formed on an aluminum or steel base 202.
- Layer 201 defines a cylindrical transfer surface 207 to which several single color toner images are transferred directly to form a multicolor image.
- a pair of gudgeons 203 and 204 support base 202 and are journaled for rotation about fixed shafts 205 and 206.
- Shafts 205 and 206 rotate about different portions of a single axis of rotation and are considered a single shaft for all purposes herein.
- Shafts 205 and 206 are fixed in mechanism plates 208 and 209 of the printer, and support an internal drive housing 210 located inside transfer drum 10.
- Internal drive housing 210 includes a motor 212 and planetary gear box 213.
- the planetary gear box provides a suitable gear reduction between the motor and an output shaft 221.
- a drive gear 222 is fixed on output shaft 221 and is rotated by output shaft 221 to drive a first idler gear 225.
- First idler gear 225 is fixed to an idler shaft 226 journaled for rotation with respect to drive housing 210.
- a second idler gear 227 is also fixed to and is rotated by idler shaft 226.
- Second idler gear 227 engages an internal gear 230 fixed to the inside of drum base 202 to rotate drum 10 with respect to shafts 205 and 206 and housing 210.
- the structure shown in Fig. 15 is particularly useful to drive a transfer drum 10 which receives toner images directly to its surface and then transfers them to a receiving sheet, because such a drum does not require a vacuum source or other structure for holding a receiving sheet to the drum surface, thereby leaving the room necessary for the transfer drum drive housing 210. It is also particularly useful with a cartridge loading image member 2 as shown in Figs. 2-5 which image member is driven by transfer drum 10, since, with such a structure, no usable space is taken up in printer 1 for a drive for either of drums 10 or 2.
- cartridge 3 is shown supported by receiving mechanism 50 which positions the cartridge so that sufficient engagement between drum 2 and drum 10 is obtained to both transfer images and drive drum 2.
- receiving mechanism 50 which positions the cartridge so that sufficient engagement between drum 2 and drum 10 is obtained to both transfer images and drive drum 2.
- Fig. 3 construction is feasible for modest image quality.
- tolerances in the manufacture of cartridge 3 receiving structure 50 and the location of drum 10 become confining. Accordingly, more precise positioning mechanisms are shown in Figs.4-14.
- cartridge 3 includes drum 2, charging station 4 and cleaning device 12, but does not include a sump for receiving toner cleaned from drum 10.
- Transfer drum 10 is supported on a shaft 51 which, in turn, is supported by a pair of mechanism plates of the apparatus, for example, mechanism plates 208 and 209, shown in Fig. 15.
- Also supported on shaft 51 are a pair of triangularly shaped plates 52 at opposite ends of drum 10. Plates 52 are also connected by an auxiliary shaft 54 and are generally rotatable about an axis 53 by a shaft 51 but rigidly fixed with respect to each other.
- Photoconductive drum 2 is supported for rotation about an axis 56 by a shaft 57 which shaft extends beyond the end walls of cartridge 3.
- Drum 2 rotates with respect to shaft 57, so shaft 57 is fixed with respect to cartridge 3.
- a slot 55 in each of triangular plates 52 is shaped to receive snugly the ends of shaft 57.
- plates 52 can be rotated to a position slightly counterclockwise from that shown in Fig. 4 to receive shaft 57 into slots 55. Plates 52, transfer drum 10 and cartridge 3 are then rotated clockwise around shaft 51 until plates 52 rest on a stop 62 which is a permanent portion of printer 1. The cartridge 3 can still be rotated about shaft 57 until a portion of cartridge 3 rests on another stop 61 which is also a permanent part of printer 1.
- Stops 61 and 62 generally orient the cartridge in printer 1 for access to the exposing and developing devices 5 and 6 (Figs. 1 and 3).
- the nip between drums 10 and 2 is controlled by a spring 65 which urges cartridge 3 toward transfer drum 10 and the image surface of drum 2 into engagement with the transfer surface associated with drum 10.
- a spring 67 may also be used to maintain the contact between cartridge 3 and stop 61, thereby preventing rotation of the cartridge around shaft 57. Spring 67 may not in fact be necessary, since the rotation of transfer drum 10 will also urge cartridge 3 against stop 61.
- spring 67 can be part of an upper part of printer 1 which, after the insertion of cartridge 3 is closed onto a lower part, which lower part holds motor 42, transfer drum 10, laser 5, development device 6 and associated support structure.
- Spring 65 although part of the lower portion of the apparatus, can also be tensioned and/or applied to cartridge 3 as part of this closing operation.
- Transfer drum 10 is supported on a shaft 111, which, in turn, is supported by front and rear guide plates 112 and 113, respectively.
- Shaft 111 may be in two sections as are shafts 205 and 206 shown in Fig. 15.
- Guide plates 112 and 113 extend substantially to the right from transfer drum 10 and each include control surfaces 115 and support surfaces 116 which cooperate with portions of cartridge 103.
- an over-center spring mechanism 120 is actuated to drive cartridge 103 from an unloaded condition shown in Figs. 7 and 9 to a fully loaded condition shown in Figs. 8 and 10.
- Cartridge 103 is positioned in the apparatus by the operator resting left and right rear support bosses 131 and 132, respectively, on rear support surface 116 as shown in Fig. 9, a single front support boss 133 on front guide surface 116, with all three support bosses thus resting on support surfaces 116.
- Support surfaces 116 are generally horizontal.
- Drum 2 is mounted in cartridge 103 on a support shaft 105 (which also may be in two sections as shown in Fig. 15), and rotates about an axis at the center of the shaft.
- Over-center spring 120 is actuated (as described below) to push cartridge 103 to the left as shown in Fig. 8. This action pushes shaft 105 into contact with control surfaces 115 of guide plates 112 and 113. Control surfaces 115 are parallel with each other. Their projection is generally tangent to transfer drum shaft 111. As seen in Figs. 8 and 10, over-center spring 120 pushes cartridge 103 until shaft 105 rides up control surfaces 115 until drum 2 engages transfer drum 10. A notch 119 in guide plates 112 and 113 causes cartridge 103 to no longer be supported by bosses 131 and 133.
- cartridge 103 is supported only by the ends of shaft 105 riding up parallel control surfaces 115 and by boss 132 resting on support surface 116.
- This three-point contact forces shaft 105 to always contact both control surfaces 115.
- the peripheral surfaces of drums 2 and 10 are cylindrical and accurately mounted on shafts 105 and 111, and the location of control surfaces 115 are accurate, the axes of drums 2 and 10 will be parallel.
- a roller 160 is shown in Figs. 11 and 12, and is part of a structure to prevent movement of cartridge 103 to the rear.
- a complementary roller or spring to the front of the path of cartridge 103 is not shown.
- Cartridge 103 can be pushed to the left (as seen in Fig. 8) by any appropriate spring mechanism.
- Figs. 6, 11 and 12 illustrate an over-center spring mechanism 120 which is particularly useful for this function.
- lever 124 is generally urged by springs 127 toward either a latched condition shown in Figs. 6, 8, 10 and 12 or toward an unlatched condition shown in Figs. 5, 7, 9 and 11.
- knob 121 is turned in either direction until protrusion 154 engages one of groove ends 156 or 157. From that point on, rotation of knob 121 rotates shaft 122 until the "over-center" condition of springs 127 occurs. At this point, the spring accelerates the rotation of lever 124 in either a latching or unlatching direction causing the shaft 122 to rotate ahead of either groove end 156 or 157 until lever 124 reaches its fully latched or unlatched condition.
- This design has the advantage of fully positioning the lever 124 without the spring acceleration of lever 124 or its stopping being felt by the person rotating knob 121. It also discourages over rotation of lever 124 by the operator which can damage cartridge 103 or drums 2 or 10.
- the positioning device shown in Figs. 5-14 positions the photoconductive drum 2 against the transfer drum 10 with the axes of revolution of the two drums parallel. Precision is required in only the manufacture and assembly of shafts 111 and 105, drums 2 and 10 and guide surfaces 115. This parallelism is important to prevent image degradation in high-quality transfer. This makes it particularly usable in a multicolor printer providing high-quality multicolor images which are the results of superimposing a series of single color images. It is particularly usable when the photoconductive drum is driven by the transfer drum (as shown in Figs. 1-4) because such driving engagement between the two drums requires a substantial nip which increases the degradation of the image if the axes are not parallel. However, it certainly can be used in structures in which the photoconductive drum 2 is driven by its own drive means and either drives the transfer drum or is driven independently of it.
- Shaft 105 is preferably a stationary shaft with photoconductive drum 2 mounted for rotation with respect to it. This eliminates the necessity of making guide surfaces 115 bearing surfaces. Shaft 111 can rotate with transfer drum 10 or be stationary, with transfer drum 10 rotating with respect to it as shown in Fig. 15.
- Shaft 105 could be rotatable with photoconductive drum 2. In such a design, it would be preferable to have shaft 105 supported for rotation in bearings, which bearings have a housing which contacts guide surfaces 115. Alternatively, if surfaces 115 are made of self-lubricating material, shaft 105 can rotate with drum 2 on surfaces 115.
- each of the positioning structures shown herein has particular adaptability and is designed for a transfer drum 10 which receives toner images directly on its outer transfer surface
- the structures can also be used with a transfer drum which supports a receiving sheet on its outer surface.
Description
- This invention relates to an image forming apparatus which uses a cartridge containing an image member on which transferable toner images are formed.
- U.S. Patent 4,876,577, Ogura et al, issued October 24, 1989, shows an electrophotographic apparatus which receives a cartridge containing a photoconductive drum. The cartridge includes both a charging mechanism for charging the drum and a cleaning mechanism for cleaning it. An access opening is provided for imagewise exposure of a charged surface of the drum to create an electrostatic image on the drum. The electrostatic image is toned through another access opening in the cartridge by one of two toning stations which are rotatable into position opposite the access opening to create a toner image. The toner image is transferred to a receiving sheet fed through a receiving sheet opening into contact with the drum. The receiving sheet is separated from the drum by a special mechanism which is part of the cartridge and fed outside of the cartridge to a fusing device.
- U.S. Patent 4,591,258, to Nishino et al, issued May 27, 1986, shows a cartridge containing a rotatable photoconductive drum with charging, cleaning and development stations also within the cartridge. An access opening to the drum permits transfer of toner images to a receiving sheet fed into engagement with the drum. Rotation of the drum is accomplished by a driving connection at the end of the cartridge which must mate with a drive member in the receiving apparatus. Projections are provided on the cartridge to prevent damage to the cartridge driving connection member from careless handling.
- Many other references show such image member cartridges, and they are used commercially in personal copiers and laser printers. In general, the photoconductive drum is driven by an end connection to the drum through an end of the cartridge. Mounting of the cartridge in the image forming apparatus requires assuring that the drive connection is effectively made.
- U.S. Patent 4,712,906, to Bothner et al, issued December 15, 1987, shows a transfer drum for a color printer. In one embodiment, a series of different color toner images are transferred to a receiving sheet carried by the drum which rotates to repeatably present the receiving sheet to an image member. In another embodiment, the different color toner images are transferred directly to the outside surface of a transfer drum to create a multicolor image on the transfer drum which is subsequently transferred in a single step to a receiving sheet at a position remote from the image member. Other references show an intermediate transfer member in the form of an endless web rather than a drum; see for example, U.S. Patent 4,453,820, Suzuki, issued June 12, 1984.
- U.S. Patent 4,299,474 to Ernst et al, issued November 10, 1981, shows a compact desk-top copier in which space is saved by putting the motor, cooling system and drives for a photoconductive image member inside the image member. This structure utilizes what had previously been generally unused space to house substantial, necessary components, thereby reducing the size of the copier.
- It is an object of the invention to accurately position an image member loaded in an image forming apparatus as part of an image member cartridge with respect to a transfer surface associated with a transfer member which transfer member is not part of the cartridge.
- This and other objects are accomplished by an image forming apparatus which includes a replaceable cartridge supporting an image member. The cartridge includes an access opening for transfer of toner images from the image member to a transfer surface. The image forming apparatus includes a transfer member not part of the cartridge and having a transfer surface associated with it for receiving toner images from the image member. The cartridge is urged toward the transfer member to urge the image member into transfer engagement with the transfer surface. Control structure associated with the transfer member engages the cartridge to accurately position the image member with respect to the transfer member.
- The image member is drum-shaped, having a cylindrical outer image surface upon which toner images are formed as the image member rotates about an axis of rotation. The transfer member is a transfer drum also having an axis of rotation and a cylindrical outer surface. The image forming apparatus includes means for controlling the relative positions of the axes of rotation of the transfer member and the image member to maintain them parallel. Maintenance of parallelism between the axes of rotation of the image member and transfer member prevents image degradation during transfer.
- In the detailed description of the preferred embodiment of the invention presented below, reference is made to the accompanying drawings, in which:
- Fig. 1 is a perspective schematic of an image forming apparatus with housing and other support parts eliminated for clarity of illustration.
- Fig. 2 is a perspective view illustrating the drive train of an image forming apparatus with some parts in phantom and other parts eliminated for clarity of illustration.
- Fig. 3 is a front schematic of the image forming apparatus shown in Fig. 1 with portions of an image member cartridge shown in cross section for clarity of illustration.
- Fig. 4 is a front schematic of the drive train and cartridge portions of the image forming apparatus with portions eliminated and broken away for clarity of illustration.
- Fig. 5 is a perspective view of a cartridge and a mounting structure portion of an alternative image forming apparatus.
- Fig. 6 is a perspective view of an over-center spring mechanism forming a part of the apparatus shown in Fig. 5.
- Figs. 7 and 8 are front views of the structure shown in Fig. 5 in its partially loaded and fully loaded conditions, respectively.
- Figs. 9 and 10 are rear views of the structure shown in Figs. 7 and 8 also in its partially loaded and fully loaded conditions, respectively.
- Figs. 11 and 12 are top views of the structure shown in Figs. 5-10 in its partially loaded and fully loaded conditions, respectively.
- Figs. 13 and 14 are front and rear views, respectively, of a circular disk which forms part of a
knob 121 shown in Figs. 5 and 6. - Fig. 15 is a top section of a transfer drum illustrating an alternative drive mechanism for the apparatus shown in Fig. 1.
- An image forming apparatus, for example, a printer 1, is shown in Fig. 1 with housing and support structures eliminated for clarity of illustration. Printer 1 includes an image member, for example, a
photoconductive drum 2 which is rotatable through a series of stations for forming a series of toner images of different colors.Photoconductive drum 2 has a cylindrical image surface which is first charged by acharging station 4 and then imagewise exposed by alaser 5 to create a series of electrostatic images. The electrostatic images are toned by toners of different color by amovable development device 6 which includes 3 or 4 separate development units. Each unit applies a different color toner to one of the series of electrostatic images to create a series of different color toner images on the cylindrical image surface ofdrum 2. The series of different color toner images are transferred in registration to a transfer surface associated with atransfer drum 10 to create a multicolor color image on that surface. As shown in Fig. 1, the surface to which the toner images are transferred is a cylindrical peripheral surface ofdrum 10 itself. However, the toner images could also be transferred to a receiving sheet held on the surface ofdrum 10 as is well known in the art. - The multicolor image is transferred by a
transfer station 21 to a receiving sheet fed from areceiving sheet supply 45. The receiving sheet is then transported to afuser 23 where the multicolor image is fixed and then to an output hopper 44 through an inverting path. - After transfer of the multicolor image from the surface of
drum 10 to the receiving sheet, the transfer surface of thetransfer drum 10 is cleaned by an articulatingcleaner 30 so that it may receive a new set of images. Thephotoconductive drum 2 is cleaned continuously during image formation by acleaning device 12. - As will be shown in later Figs., the
photoconductive drum 2 is supplied to the printer 1 in acartridge 3 which cartridge may also contain other portions of printer 1. For example, the cartridge may contain thecharging device 4, the developingdevice 6 and/orcleaning devices - One example of such a
cartridge 3 is shown in Fig. 3 in which the cartridge housing is shown in section while the rest of the apparatus is shown schematically. According to Fig. 3, a cartridge housing containsimage member 2, an opening for exposure bylaser 5,charging device 4 and imagemember cleaning device 12. It also includes a sump 11 for receiving toner cleaned bycleaning device 12 offimage member 2 and asump 35 for receiving toner cleaned offtransfer drum 10 bytransfer drum cleaner 30. The housing also includes an opening 7 providing access toimage member 2 fordevelopment device 6 and an opening 9 providing access toimage member 2 fortransfer drum 10. - Articulating cleaner 30 is moved in and out of engagement with
transfer drum 10 by asolenoid 31. It includes a cleaning roller which rolls on the surface oftransfer drum 10 which roller is biased and formed of a material which encourages removal of toner to the roller. Cleaned toner is scraped off the roller by ascraping blade 32. Anopening 36 in the cartridge housing receives scraped toner intosump 35. - A receiving sheet is fed from a receiving
sheet supply 20 into transfer relation withtransfer drum 10. In the structure shown in Fig. 3, transfer is accomplished by acorona transfer station 21, known in the art. The transfer sheet is picked offtransfer drum 10 by a movable pick-off 22 which also directs the transfer sheet tofuser 23. - Prior cartridges which contained image members such as
photoconductive drum 2 included a relatively complex drive connector at one end of the cartridge which must be engaged with an appropriate drive in the receiving apparatus to rotatedrum 2 past the toner image forming stations. As shown in Figs. 2 and 3, the need for such a drive connector is eliminated. Amotor 42 drives adrive gear 40 which in turn drives agear 44 connected to transferdrum 10.Transfer drum 10 is made up of material somewhat softer thanphotoconductive drum 2, for example, polyurethane.Photoconductive drum 2 engagestransfer drum 2 throughopening 9 and is frictionally driven bytransfer drum 10 for its entire operation. Thus, opening 9 provides access toimage member 2 for both transfer and for frictional, driving engagement withtransfer drum 10. With this structure, no separate drive connection needs to be made betweentransfer drum 2 and the receiving apparatus. This greatly simplifies the manufacture of the cartridge and its cost as well as loading of thecartridge 3 in the printer 1. Fig. 2 is a perspective drawing illustrating the drive train frommotor 42 throughtransfer drum 10 andphotoconductive drum 2. - The term "engagement" as used herein with reference to the image member and the transfer member is preferably direct contacting engagement of those members. However, although not preferred, it can also be engagement through a receiving sheet carried by the transfer member.
- Although
transfer drum 10 is shown with an external drive engagement betweentransfer drum 10 andmotor 42,motor 42 could be positioned insidetransfer drum 10 and internally engaged withdrum 10 to save space in printer 1. This latter embodiment is shown in Fig. 15. - According to Fig. 15,
transfer drum 10 includes anouter layer 201 of polyurethane cast or otherwise formed on an aluminum orsteel base 202.Layer 201 defines acylindrical transfer surface 207 to which several single color toner images are transferred directly to form a multicolor image. A pair ofgudgeons support base 202 and are journaled for rotation about fixedshafts -
Shafts Shafts mechanism plates transfer drum 10. Internal drive housing 210 includes a motor 212 and planetary gear box 213. The planetary gear box provides a suitable gear reduction between the motor and anoutput shaft 221. Adrive gear 222 is fixed onoutput shaft 221 and is rotated byoutput shaft 221 to drive afirst idler gear 225. Firstidler gear 225 is fixed to anidler shaft 226 journaled for rotation with respect to drive housing 210. Asecond idler gear 227 is also fixed to and is rotated byidler shaft 226.Second idler gear 227 engages aninternal gear 230 fixed to the inside ofdrum base 202 to rotatedrum 10 with respect toshafts hole 217 in the center ofshaft 206 provides an exit for wiring the motor 212. - With the structure shown in Fig. 15,
transfer drum 10 comes to printer 1 with its own internal drive. That drive does not need to be separately mounted in the printer, saving a step in printer final assembly. More importantly, the drive does not take up space in the printer, allowing the printer to be more compact. - The structure shown in Fig. 15 is particularly useful to drive a
transfer drum 10 which receives toner images directly to its surface and then transfers them to a receiving sheet, because such a drum does not require a vacuum source or other structure for holding a receiving sheet to the drum surface, thereby leaving the room necessary for the transfer drum drive housing 210. It is also particularly useful with a cartridgeloading image member 2 as shown in Figs. 2-5 which image member is driven bytransfer drum 10, since, with such a structure, no usable space is taken up in printer 1 for a drive for either ofdrums - Although driving the
image member 2 utilizing peripheral engagement withtransfer drum 10 through access opening 9 greatly simplifiescartridge 3, some precision in the placement ofcartridge 3 is important in this apparatus. In the structure shown in Fig. 3,cartridge 3 is shown supported by receivingmechanism 50 which positions the cartridge so that sufficient engagement betweendrum 2 and drum 10 is obtained to both transfer images and drivedrum 2. For best image quality, it is necessary to control both the size of the nip between the drums and to maintain the axes of rotation of the drums parallel. To do this with the Fig. 3 construction is feasible for modest image quality. However, for highest image quality, tolerances in the manufacture ofcartridge 3, receivingstructure 50 and the location ofdrum 10 become confining. Accordingly, more precise positioning mechanisms are shown in Figs.4-14. - According to Fig. 4,
cartridge 3 includesdrum 2, chargingstation 4 andcleaning device 12, but does not include a sump for receiving toner cleaned fromdrum 10.Transfer drum 10 is supported on ashaft 51 which, in turn, is supported by a pair of mechanism plates of the apparatus, for example,mechanism plates shaft 51 are a pair of triangularly shapedplates 52 at opposite ends ofdrum 10.Plates 52 are also connected by anauxiliary shaft 54 and are generally rotatable about anaxis 53 by ashaft 51 but rigidly fixed with respect to each other. -
Photoconductive drum 2 is supported for rotation about anaxis 56 by ashaft 57 which shaft extends beyond the end walls ofcartridge 3.Drum 2 rotates with respect toshaft 57, soshaft 57 is fixed with respect tocartridge 3. Aslot 55 in each oftriangular plates 52 is shaped to receive snugly the ends ofshaft 57. - To load
cartridge 3 in the embodiment shown in Fig. 4,plates 52 can be rotated to a position slightly counterclockwise from that shown in Fig. 4 to receiveshaft 57 intoslots 55.Plates 52,transfer drum 10 andcartridge 3 are then rotated clockwise aroundshaft 51 untilplates 52 rest on astop 62 which is a permanent portion of printer 1. Thecartridge 3 can still be rotated aboutshaft 57 until a portion ofcartridge 3 rests on anotherstop 61 which is also a permanent part of printer 1. -
Slots 55 inplates 52 are parallel with each other and define control surfaces which maintain a parallel relation between the axes of rotation ofdrums Stops devices 5 and 6 (Figs. 1 and 3). The nip betweendrums spring 65 which urgescartridge 3 towardtransfer drum 10 and the image surface ofdrum 2 into engagement with the transfer surface associated withdrum 10. Aspring 67 may also be used to maintain the contact betweencartridge 3 and stop 61, thereby preventing rotation of the cartridge aroundshaft 57.Spring 67 may not in fact be necessary, since the rotation oftransfer drum 10 will also urgecartridge 3 againststop 61. However,spring 67 can be part of an upper part of printer 1 which, after the insertion ofcartridge 3 is closed onto a lower part, which lower part holdsmotor 42,transfer drum 10,laser 5,development device 6 and associated support structure.Spring 65, although part of the lower portion of the apparatus, can also be tensioned and/or applied tocartridge 3 as part of this closing operation. - Figs. 5-12 show another approach to positioning an image member cartridge in an image forming apparatus similar to that shown in Fig. 1. According to Fig. 5, a
cartridge 103 containing animage member 2 is to be loaded into an apparatus which includes atransfer drum 10 with the axes of rotation ofdrums -
Transfer drum 10 is supported on a shaft 111, which, in turn, is supported by front andrear guide plates shafts Guide plates transfer drum 10 and each includecontrol surfaces 115 and support surfaces 116 which cooperate with portions ofcartridge 103. - As best seen in Figs. 7-10, an
over-center spring mechanism 120 is actuated to drivecartridge 103 from an unloaded condition shown in Figs. 7 and 9 to a fully loaded condition shown in Figs. 8 and 10. -
Cartridge 103 is positioned in the apparatus by the operator resting left and rightrear support bosses rear support surface 116 as shown in Fig. 9, a singlefront support boss 133 onfront guide surface 116, with all three support bosses thus resting on support surfaces 116. Support surfaces 116 are generally horizontal. -
Drum 2 is mounted incartridge 103 on a support shaft 105 (which also may be in two sections as shown in Fig. 15), and rotates about an axis at the center of the shaft.Over-center spring 120 is actuated (as described below) to pushcartridge 103 to the left as shown in Fig. 8. This action pushesshaft 105 into contact withcontrol surfaces 115 ofguide plates over-center spring 120 pushescartridge 103 untilshaft 105 rides upcontrol surfaces 115 untildrum 2 engagestransfer drum 10. Anotch 119 inguide plates causes cartridge 103 to no longer be supported bybosses - Thus, in its fully loaded condition shown in Figs. 8 and 10, with
drum 2 engagingdrum 10,cartridge 103 is supported only by the ends ofshaft 105 riding upparallel control surfaces 115 and byboss 132 resting onsupport surface 116. This three-pointcontact forces shaft 105 to always contact both control surfaces 115. Thus, to the extent that the peripheral surfaces ofdrums shafts 105 and 111, and the location ofcontrol surfaces 115 are accurate, the axes ofdrums - The extent of the parallelness between the axes is a determining factor on the image quality in transfer. If, for example, the
support boss 133 were allowed to continue to contactguide surface 116, it would be possible for either end ofshaft 105 to become out of contact with itscontrol surface 115, thereby losing parallelness between the axes of rotation of the drums. This might be overcome by preciseness in the manufacture of the housing ofcartridge 103 andbosses drum 2 and itssupport shaft 105. In the receiving apparatus,control surfaces 115 also must be accurately positioned with respect to shaft 111 and shaft 111 must be accurately positioned with respect to transferdrum 10. - A
roller 160 is shown in Figs. 11 and 12, and is part of a structure to prevent movement ofcartridge 103 to the rear. A complementary roller or spring to the front of the path ofcartridge 103 is not shown. - It also may be desirable to urge the top of the cartridge gently in a downward direction during operation to prevent engagement of the drums from unseating it. This can be accomplished with a spring applied as part of closing the apparatus after loading of
cartridge 103. -
Cartridge 103 can be pushed to the left (as seen in Fig. 8) by any appropriate spring mechanism. However, Figs. 6, 11 and 12 illustrate anover-center spring mechanism 120 which is particularly useful for this function. - As best seen in Figs. 5, 6, 11 and 12, a
support housing 125 is attached to printer 1 by suitable means, not shown, and supports the rest ofover-center spring mechanism 120. Referring to Fig. 6, a customer actuatedknob 121 is rotated by theperson inserting cartridge 103.Knob 121 is keyed through ashaft 122 to a drive roller orgear 128. Rotation ofknob 121 rotates driveroller 128 which in turn rotates a drivenroller 123.Driven roller 123 is keyed to alever 124 through ashaft 126. Thus, rotation ofknob 121 rotateslever 124 aroundshaft 126.Lever 124 pushescartridge 103 into its loaded condition and holds it there with the desired force urging engagement ofdrums - A pair of
springs 127 are mounted between aspring support 141 onhousing 125 and a spring support rod 142 (Fig. 5) onlever 124.Shaft 126 is between the attaching positions ofsprings 127. Thus, springs 127 have a dead-center position between latched and unlatched conditions oflever 124 where theshaft 126 lines up with the attaching positions. That is, asknob 121 is rotated in a counterclockwise direction as seen in Fig. 6,lever 124 is driven in a clockwise direction toward a latchingposition urging cartridge 103 to the left untilphotoconductive drum 2 engagestransfer drum 10. In this movement,spring 127 goes through a "dead-center" position in which it is at its maximum length and therefore its maximum stressed condition. Further clockwise rotation oflever 124 causessprings 127 to urgelever 124 into engagement withcartridge 103 andcartridge 103 into its loaded condition as shown in Fig. 8. To unloadcartridge 103,knob 121 is rotated in a clockwise direction to rotatelever 124 in a counterclockwise direction as seen in Fig. 6 untilsprings 127 pass through their dead center position. At this point, further rotation ofknob 121 is aided bysprings 127 urginglever 124 toward its totally unlatched position, shown in Fig. 5 withlever 124 resting against a pair of lever stops 143 wherelever 124 will not interfere with removal of the cartridge. Thus, with theover-center spring structure 120,lever 124 is generally urged bysprings 127 toward either a latched condition shown in Figs. 6, 8, 10 and 12 or toward an unlatched condition shown in Figs. 5, 7, 9 and 11. -
Knob 121 can be constructed so that the customer who is loading the cartridge does not, in fact, feel the final positioning of the cartridge in its loaded condition or the positioning oflever 124 againststops 143.Knob 121 includes acircular plate 149, the front and rear sides of which are shown in Figs. 13 and 14, respectively. Driveshaft 122 is positioned in ahole 152 throughplate 149. The front surface ofplate 149 includes agroove 153 contiguous with the front portion ofhole 152.Shaft 122 includes aprotrusion 154 which rides ingroove 153 except where not permitted byends groove 153. - In operation,
knob 121 is turned in either direction untilprotrusion 154 engages one of groove ends 156 or 157. From that point on, rotation ofknob 121 rotatesshaft 122 until the "over-center" condition ofsprings 127 occurs. At this point, the spring accelerates the rotation oflever 124 in either a latching or unlatching direction causing theshaft 122 to rotate ahead of eithergroove end lever 124 reaches its fully latched or unlatched condition. This design has the advantage of fully positioning thelever 124 without the spring acceleration oflever 124 or its stopping being felt by theperson rotating knob 121. It also discourages over rotation oflever 124 by the operator which can damagecartridge 103 ordrums - The positioning device shown in Figs. 5-14 positions the
photoconductive drum 2 against thetransfer drum 10 with the axes of revolution of the two drums parallel. Precision is required in only the manufacture and assembly ofshafts 111 and 105,drums photoconductive drum 2 is driven by its own drive means and either drives the transfer drum or is driven independently of it. - Note that the manufacture and location of
bosses guide surface 115 maintains parallelism ofshafts 105 and 111. If the two shafts are the same size, surfaces 115 should be parallel with each other and their extensions should be tangent to the periphery of shaft 111. If shaft 111 is larger thanshaft 105, extensions of guide surfaces 115 should intersect shaft 111 accordingly.Shaft 105 is preferably a stationary shaft withphotoconductive drum 2 mounted for rotation with respect to it. This eliminates the necessity of makingguide surfaces 115 bearing surfaces. Shaft 111 can rotate withtransfer drum 10 or be stationary, withtransfer drum 10 rotating with respect to it as shown in Fig. 15. -
Shaft 105 could be rotatable withphotoconductive drum 2. In such a design, it would be preferable to haveshaft 105 supported for rotation in bearings, which bearings have a housing which contacts guide surfaces 115. Alternatively, ifsurfaces 115 are made of self-lubricating material,shaft 105 can rotate withdrum 2 onsurfaces 115. - Although each of the positioning structures shown herein has particular adaptability and is designed for a
transfer drum 10 which receives toner images directly on its outer transfer surface, the structures can also be used with a transfer drum which supports a receiving sheet on its outer surface. - The invention has been described in detail with particular reference to a preferred embodiment thereof, but it will be understood that variations and modifications can be effected within the scope of the invention as defined in the appended claims.
Claims (5)
- An image forming apparatus comprising:a replaceable cartridge (3) having a housing and a drum-shaped image member (2), a shaft (57; 105) supporting said image member for rotation about an axis of rotation (56), said shaft (57;105) having opposite ends which extend beyond opposite ends of said image member (2) and are accessible from outside of said cartridge housing, said image member (2) having an image surface upon which toner images are formable,a transfer drum (10) having an axis of rotation (53) and a cylindrical outer transfer surface for receiving toner images from said image surface, andmeans (52; 115) fixed with respect to the axis of rotation (53) of said transfer drum (10) for controlling the position of the shaft (57; 105) supporting the image member to maintain the axis of rotation (56) of said image member parallel to the axis of rotation (53) of said transfer drum (10).
- An image forming apparatus according to claim 1 wherein said shaft (57; 105) is fixed with respect to said cartridge (3) and said image member (2) is mounted for rotation with respect to said shaft (57; 105) and said shaft (57; 105) has opposite ends which extend outside of said cartridge (3) for engagement by said controlling means (52; 115).
- An image forming apparatus according to claim 1 or 2 and further including means (65, 67;120) for urging said cartridge toward said transfer drum (10) to urge said image surface into engagement with said transfer surface.
- An image forming apparatus according to claim 3 wherein said controlling means (52; 115) includes at least a pair of control surfaces (115), one control surface engaging each opposite end of said shaft (57; 105), said control surfaces (55; 115) running from positions of engagement of said control surfaces with the ends of said shaft (57; 105) toward said transfer drum (10), and said urging means (65, 67; 120) including means for urging said cartridge in a direction maintaining contact between the ends of the shaft and said control surfaces while also urging said image surface into engagement with said transfer surface.
- An image forming apparatus according to claim 1 to 4 wherein said transfer drum (10) is supported by a shaft (51; 111) having opposite ends, which ends are fixed with respect to said controlling means (52;115).
Applications Claiming Priority (7)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US65025991A | 1991-02-04 | 1991-02-04 | |
US650259 | 1991-02-04 | ||
US07/650,260 US5087939A (en) | 1991-02-04 | 1991-02-04 | Image forming apparatus and image member cartridge |
US650325 | 1991-02-04 | ||
US650260 | 1991-02-04 | ||
US07/650,325 US5138372A (en) | 1991-02-04 | 1991-02-04 | Image forming apparatus and an image member cartridge |
EP92912927A EP0523235B1 (en) | 1991-02-04 | 1992-02-03 | Image forming apparatus and image member cartridge |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP92912927.8 Division | 1992-09-11 |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0651300A2 EP0651300A2 (en) | 1995-05-03 |
EP0651300A3 EP0651300A3 (en) | 1995-09-20 |
EP0651300B1 true EP0651300B1 (en) | 1997-06-18 |
Family
ID=27417841
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP95100526A Expired - Lifetime EP0651300B1 (en) | 1991-02-04 | 1992-02-03 | Image forming apparatus |
EP92912927A Expired - Lifetime EP0523235B1 (en) | 1991-02-04 | 1992-02-03 | Image forming apparatus and image member cartridge |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP92912927A Expired - Lifetime EP0523235B1 (en) | 1991-02-04 | 1992-02-03 | Image forming apparatus and image member cartridge |
Country Status (4)
Country | Link |
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EP (2) | EP0651300B1 (en) |
JP (1) | JPH06501574A (en) |
DE (2) | DE69203807T2 (en) |
WO (1) | WO1992015049A2 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2012203308A (en) * | 2011-03-28 | 2012-10-22 | Fuji Xerox Co Ltd | Image forming apparatus and transfer device |
Family Cites Families (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5788461A (en) * | 1980-11-22 | 1982-06-02 | Canon Inc | Picture formation device |
JPS58105268A (en) * | 1981-12-18 | 1983-06-23 | Fuji Xerox Co Ltd | Transfer device of electrophotographic copying machine |
JPS5997167A (en) * | 1982-11-26 | 1984-06-04 | Konishiroku Photo Ind Co Ltd | Electrostatic recorder |
JPS59220756A (en) * | 1983-05-30 | 1984-12-12 | Konishiroku Photo Ind Co Ltd | Recording device |
US4723145A (en) * | 1985-03-22 | 1988-02-02 | Canon Kabushiki Kaisha | Color image forming apparatus comprising separate motors for driving the image bearing member and the transfer material supporting member |
US4712906A (en) * | 1987-01-27 | 1987-12-15 | Eastman Kodak Company | Electrostatographic apparatus having a transfer drum |
NL8702691A (en) * | 1987-11-11 | 1989-06-01 | Oce Nederland Bv | Apparatus for transferring a powder image to a receiving material and fixing the powder image thereon. |
JP2686267B2 (en) * | 1988-01-30 | 1997-12-08 | キヤノン株式会社 | Image forming device |
EP0376617B1 (en) * | 1988-12-27 | 1994-03-02 | Konica Corporation | Color image forming apparatus |
US5070370A (en) * | 1990-12-24 | 1991-12-03 | Eastman Kodak Company | Image-forming apparatus having a replaceable cartridge and a transfer member cleaning device |
-
1992
- 1992-02-03 EP EP95100526A patent/EP0651300B1/en not_active Expired - Lifetime
- 1992-02-03 DE DE69203807T patent/DE69203807T2/en not_active Expired - Fee Related
- 1992-02-03 WO PCT/US1992/000675 patent/WO1992015049A2/en active IP Right Grant
- 1992-02-03 EP EP92912927A patent/EP0523235B1/en not_active Expired - Lifetime
- 1992-02-03 JP JP4511583A patent/JPH06501574A/en active Pending
- 1992-02-03 DE DE1992620510 patent/DE69220510T2/en not_active Expired - Fee Related
Also Published As
Publication number | Publication date |
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EP0523235B1 (en) | 1995-08-02 |
DE69220510D1 (en) | 1997-07-24 |
WO1992015049A3 (en) | 1993-01-21 |
EP0651300A2 (en) | 1995-05-03 |
JPH06501574A (en) | 1994-02-17 |
DE69203807D1 (en) | 1995-09-07 |
WO1992015049A2 (en) | 1992-09-03 |
DE69220510T2 (en) | 1997-12-04 |
EP0651300A3 (en) | 1995-09-20 |
EP0523235A1 (en) | 1993-01-20 |
DE69203807T2 (en) | 1996-03-21 |
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