Image forming apparatus with a scanner input

Information

  • Patent Grant
  • 6263185
  • Patent Number
    6,263,185
  • Date Filed
    Thursday, October 7, 1999
    25 years ago
  • Date Issued
    Tuesday, July 17, 2001
    23 years ago
Abstract
An image forming apparatus with a scanner for reading image information from a document. The image forming apparatus includes a scanner section, an image forming section, a sheet discharging section, a sheet stacking section, a sheet finishing section, and a relaying section. The scanner section is configured to read image information of a document that can then be formed into an image in the image forming section. Exemplary options include an image forming apparatus with a scanner mounted on the apparatus body above the image forming section.
Description




BACKGROUND OF THE INVENTION




The present invention relates to an image forming apparatus having a sheet transport path extending substantially vertically upward from a sheet feed section to a sheet discharge section via an image forming section. More particularly, the present invention is concerned with a printer, facsimile apparatus or similar image forming apparatus allowing a sorter, sorter/stapler, mail box or similar finisher to be readily mounted thereto.




A multifunction image forming apparatus selectively operable as, e.g., a copier, printer or facsimile apparatus is extensively used today. This kind of apparatus has customarily been provided with a construction based on a copier. Therefore, to use the apparatus as a printer, peripherals for use with the apparatus have each been provided with a mechanism for turning over sheets sequentially output in the order of page. However, the remarkable spread of personal computers is substituting a printer-based configuration for the traditional copier-based configuration. An image forming apparatus based on a printer is so constructed as to discharge a sheet carrying an image thereon via a sheet discharge section face down by way of a substantially vertically extending sheet transport path. Specifically, the printer-based apparatus has a sheet feed section and the sheet discharge section below and above an image forming section, respectively. The sheet transport path extends substantially vertically from the sheet feed section to the sheet discharge section. While a sheet is conveyed along such a transport path, a toner image is transferred to the sheet. The sheet with the toner image is driven out of the apparatus face down via the sheet discharge section. The substantially vertical transport path is far shorter than the conventional sheet transport path, noticeably reducing the interval between the sheet feed and the sheet discharge. In addition, this path can be almost fully exposed to the outside only if one side of the apparatus is opened, insuring sheet transport and promoting easy removal of a jamming sheet.




However, some problems arise when a sorter, sorter/stapler, mail box or similar finisher is mounted to the apparatus having the substantially vertical transport path. The apparatus has a sheet outlet in its upper portion. Therefore, when a mail box, for example, is mounted to the apparatus, it increases the overall height of the apparatus, and therefore raises the level of a scanner and that of an operation panel, obstructing easy operation. Moreover, mounting a mail box having a number of trays is impractical because the overall height of the apparatus is naturally limited in relation to maneuvability. In addition, the apparatus needs a mechanical strength great enough to bear the weight of the mail box, resulting in an increase in cost.




As stated above, the advantages particular to the substantially vertical transport path cannot be utilized when the above finisher is mounted to the apparatus.




When the finisher is mounted to an image forming apparatus, whether it be provided with the substantially vertical transport path or not, a conveying device for conveying a sheet driven out via the sheet discharge section of the apparatus to the finisher must be mounted to the apparatus. This cannot be done without resorting to exclusive parts and time- and labor-consuming work for mounting the conveying device to the apparatus. In addition, the conveying device increases the number of parts and cost.




There is an increasing demand for an image forming apparatus with a substantially vertical sheet transport path and allowing a plurality of finishers mounted thereto at the same time. However, it is difficult for a plurality of finishers to coexist on a single image forming apparatus. For example, mounting a mail box on the top of the apparatus while mounting a sorter/stapler on the side of the same is not easy. In light of the above, a relay unit having its own sheet transport path and sheet conveying function may be located at the upper portion of the apparatus. The relay unit connects the sheet discharge section to, e.g. a sorter/stapler mounted on the side of the apparatus which does not interfere with, e.g., a mail box mounted on the top of the apparatus. The conveying function as well as a path selecting function available with the relay unit allows the sorter/stapler and mail box to exist together on a single apparatus.




However, the problem with the relay unit is that a sheet jam is apt to occur thereinside due to its own transport path and conveying function. To obviate this kind of sheet jam, the relay unit includes a rotatable cover which may be opened in order to remove a jamming sheet. A portion for effecting usual sheet discharge is constructed integrally with the upstream side of the relay unit. A rotatable cover is also provided in this portion for the removal of a jamming sheet.




The prerequisite with the relay unit is that it be positioned close to the trays of the mail box in order to avoid a noticeable increase in the overall dimensions of the apparatus. This brings about a drawback that when any one of the covers is opened for removing a jamming sheet, the trays of the mail box limit the space available for the removal of the sheet. On the other hand, when an image reading device is mounted on the top of the apparatus, it must be positioned right above the relay unit so as not to raise the level of the operation surface of the device as far as possible. This also makes it difficult to remove a jamming sheet by hand.




SUMMARY OF THE INVENTION




It is therefore an object of the present invention to provide an image forming apparatus making the most of the advantages of a substantially vertical sheet transport path and allowing a plurality of finishers to be mounted thereto at the same time.




It is another object of the present invention to provide an image forming apparatus having a substantially vertical sheet transport path, making the most of the merits of a relay unit, and allowing a sheet jamming the tray unit or a usual sheet discharge path to be removed with ease.




It is yet another object of the present invention to provide an image forming apparatus having a substantially vertical sheet transport path, and allowing a finisher to be readily mounted thereto.




It is a further object of the present invention to provide an image forming apparatus having a substantially vertical sheet transport path, and eliminating the need for exclusive parts for mounting a finisher thereto.




In accordance with the present invention, an image forming apparatus includes a sheet discharge section provided in the upper portion of the apparatus for allowing a sheet carrying an image thereon and discharged by usual sheet discharge to be stacked on the top of the apparatus via the sheet discharge section. A relay unit extends horizontally on the top of the apparatus, and has a sheet transport path communicable to the sheet discharge section, and a conveying mechanism.




Also, in accordance with the present invention, an image forming apparatus for conveying a sheet substantially vertically from a sheet feed section positioned below an image forming section to a sheet discharge section positioned above the image forming section to thereby form an image on the sheet, and stacking, when the sheet is discharged by usual sheet discharge, the sheet on the top thereof includes a sheet receiving unit located above the sheet discharge section and including at least one tray forming a bin. A relay unit is provided in the upper portion of the apparatus for conveying the sheet driven out via the sheet discharge section to a finisher for finishing the sheet. At least the tray of the sheet receiving unit closest to the relay unit is supported to be rotatable in the up-and-down direction.




Further, in accordance with the present invention, an image forming apparatus for conveying a sheet substantially vertically from a sheet feed section positioned below an image forming section to a sheet discharge section positioned above the image forming section to thereby form an image on the sheet, and stacking, when the sheet is discharged by usual sheet discharge, the sheet on the top of the apparatus includes a sheet receiving unit located above the sheet discharge section and including at least one tray forming a bin. A relay unit is provided in the upper portion of the apparatus, for conveying the sheet driven out via the sheet discharge section to a finisher for finishing the sheet. The relay unit has a transport cover covering the top of the apparatus and divided into a plurality of cover parts in the intended direction of sheet transport. At least one of the cover parts has one end thereof supported by a shaft so as to be rotatable in the up-and-down direction.




Moreover, in accordance with the present invention, an image forming apparatus for conveying a sheet substantially vertically from a sheet feed section positioned below an image forming section to a sheet discharge section positioned above the image forming section to thereby form an image on the sheet and stacking, when the sheet is discharged by usual sheet discharge, the sheet on the top of the apparatus includes a sheet receiving unit located above the sheet discharge section and including at least one tray forming a bin. A relay unit is provided in the upper portion of the apparatus for conveying the sheet driven out via the sheet discharge section to a finisher for finishing the sheet. A usual sheet feed section is constructed integrally with the upper portion of the relay unit for discharging the sheet. A discharge cover is included in the usual sheet discharge section and rotatable in the up-and-down direction. The lowest tray of the sheet receiving unit is constructed integrally with the discharge cover.




In addition, in accordance with the present invention, an image forming apparatus includes an image forming section. A sheet feed section and a sheet discharge section are respectively located below and above the image forming section such that a sheet is fed from the sheet feed section to the sheet discharge section substantially vertically via the image forming section to thereby form an image on the sheet. A relay unit extends along the top of the apparatus and communicates the sheet discharge section to a finisher mounted on the apparatus. The relay unit includes a stack section for stacking the sheet driven out via the sheet discharge section, a first conveying device for conveying the sheet driven out via the sheet discharge section to the stacking section, a second conveying device for conveying the sheet to the finisher, a path selecting device for selectively steering the sheet to the first conveying device or to the second conveying device. A controller controls the path selecting device.











BRIEF DESCRIPTION OF THE DRAWINGS




The above and other objects, features and advantages of the present invention will become apparent from the following detailed description taken with the accompanying drawings in which:





FIGS. 1 and 2

are side elevations each showing a particular conventional image forming apparatus having a substantially vertical sheet transport path;





FIG. 3

is a side elevation showing a first embodiment of the image forming apparatus in accordance with the present invention;





FIG. 4

is a side elevation showing a second embodiment of the present invention;





FIGS. 5 and 6

are side elevations each showing a particular modification of the second embodiment;





FIG. 7

is a side elevation showing a third embodiment of the present invention;





FIG. 8

is a perspective view of a tray included in the third embodiment;





FIG. 9

is a side elevation of a relay unit included in the third embodiment with a transport cover thereof opened;





FIG. 10

is a side elevation of the relay unit with a discharge cover thereof opened;





FIG. 11

shows a perspective view of a transport cover and a tray included in a fourth embodiment of the present invention;





FIG. 12

is a side elevation showing the fourth embodiment with the transport cover opened;





FIG. 13

is a side elevation showing a fifth embodiment of the present invention;





FIG. 14

is a side elevation showing a mail box located above a relay unit of the fifth embodiment;





FIG. 15

is a perspective view showing the relay unit of the fifth embodiment pulled out from the body of the apparatus;





FIG. 16

shows the relay unit of the fifth embodiment pulled out, and a transport cover opened;





FIG. 17

is a side elevation showing the relay unit of the fifth embodiment pulled out, and a discharge cover opened;





FIG. 18

is a side elevation showing a sixth embodiment of the present invention;





FIG. 19

shows the configuration of a path selecting device included in the sixth embodiment;





FIG. 20

is a side elevation of a transport cover included in the sixth embodiment and rotated to uncover a sheet transport path;





FIG. 21

is a side elevation showing a discharge cover of the sixth embodiment in its open position;





FIG. 22

is a side elevation showing a seventh embodiment of the present invention;





FIG. 23

is a side elevation showing a transport cover part included in the seventh embodiment and rotated to uncover a sheet transport path;





FIG. 24

is a side elevation showing a modification of the seventh embodiment;





FIG. 25

is a side elevation showing an eighth embodiment of the present invention;





FIG. 26

is a side elevation showing a discharge cover included in the eighth embodiment and held in its open position;





FIG. 27

is an exploded perspective view of the eighth embodiment;





FIG. 28

is a side elevation showing a ninth embodiment of the present invention;





FIG. 29

is a block diagram schematically showing a control system included in the ninth embodiment;





FIG. 30

is a side elevation demonstrating how the ninth embodiment conveys a sheet to a stack section included in a relay unit;





FIG. 31

is a side elevation demonstrating how the ninth embodiment conveys a sheet to a finisher;





FIG. 32

is a side elevation showing how the ninth embodiment stacks sheet on the finisher when the stack section of the relay unit is filled up;





FIG. 33

is a flowchart demonstrating a specific operation of a controller included in the control system of

FIG. 29

;





FIG. 34

is a side elevation showing a tenth embodiment of the present invention;





FIG. 35

is a perspective view showing an apparatus body and a casing included in the tenth embodiment and separated from each other;





FIG. 36

is a view showing the casing of the tenth embodiment being mounted to the apparatus body; and





FIG. 37

is a view showing the casing fully mounted to the apparatus body.











DESCRIPTION OF THE PREFERRED EMBODIMENTS




To better understand the present invention, brief reference will be made to a conventional image forming apparatus including a substantially vertically extending sheet transport path, shown in FIG.


1


. As shown, the apparatus, generally


10


, includes a body


10


A. A sheet feed section


14


and a sheet discharge section


16


are respectively positioned below and above an image forming section


12


in the direction of height of the apparatus body


10


A. A sheet transport path SP extends substantially vertically from the sheet feed section


14


to the sheet discharge section


16


. The sheet feed section


14


has a tray


18


and a group of feed rollers


20


. A sheet S is fed from the tray


18


to a registration roller pair


22


by the feed rollers


20


and conveyor rollers arranged along the sheet transport path SP. A writing unit


24


forms a toner image on a photoconductive drum


26


in accordance with image data output from a scanner or a personal computer, not shown. The registration roller pair


22


drives the sheet S toward an image transfer position


28


in synchronism with the movement of the toner image carried on the drum


26


. At the transfer position


28


, the toner image is transferred from the drum


26


to the sheet S. The sheet S with the toner image is conveyed to a fixing unit


30


. After the toner image has been fixed on the sheet S by the fixing unit


30


, the sheet S is brought to the sheet discharge section


16


and driven out to the top


10




a


of the apparatus body


10


A thereby.




The sheet transport path SP is extremely short and reduces the interval between the feed of the sheet S and the discharge of the same while enhancing efficient sheet transport. In addition, the path SP can be almost fully exposed to the outside only if one side


10




b


of the apparatus body


10


A is opened, promoting extremely easy removal of a jamming sheet.




However, it is not easy with this kind of apparatus


10


to mount, eg., a mail box to the top


10




a


or to mount a sorter/stapler or similar finisher to the side, as stated earlier. This will be described with reference to

FIG. 2

specifically. As shown, assume that a mail box


32


having, e.g., four bins is mounted to the top


10




a


in a general configuration. Then, the overall height of the system increases. Particularly, when a scanner is mounted in the upper portion of the apparatus


10


, the operation surface of the scanner will be located at an extremely high level, rendering the operation difficult. Further, the increase in height of the apparatus naturally limits the number of bins available with the mail box


32


as well as the number of sheets which can be stacked. As a result, only a simple finisher with limited functions is applicable to the apparatus


10


.




In a duplex copy mode for forming images on both sides of a sheet, the sheet S carrying the toner image on side side thereof, as stated above, is turned, or switched back, in a direction SB by way of the top


10




a


of the apparatus body


10


A. Then, sheet S is routed through a duplex copy path


36


which joins the path SP at a position upstream of the registration roller pair


22


. In

FIG. 2

, the reference numeral


38


designates a manual feed unit for allowing the operator to feed sheets by hand.




Preferred embodiments of the image forming apparatus in accordance with the present invention will be described with reference to the accompanying drawings.




1st Embodiment




Referring to

FIG. 3

, an image forming apparatus embodying the present invention is shown and generally designated by the reference numeral


40


. As shown, the apparatus


40


has a body


40


A accommodating a sheet feed section


44


and a sheet discharge section


46


below and above an image forming section


42


, respectively. A sheet transport path SP


1


extends substantially vertically from the sheet feed section


44


to the sheet discharge section


46


. Major process units of the apparatus


42


, as well as the sheet feed section


14


, are built in the apparatus body


40


A. The sheet transport path SP


1


is almost fully exposed to the outside only if one side


40




b


of the apparatus


40


is opened.




A duplex copy unit


48


is mounted on the apparatus body


40


A in the vicinity of the sheet transport path SP


1


. A sorter


50


having trays or bins


50


is mounted on the apparatus body


40


A at the opposite side to the path SP


1


. The sorter


50


is a specific form of sheet discharging means or finishing means. A relay unit, or sheet discharging means,


52


is mounted on the top


40




a


of the apparatus body


40


A and extends substantially parallel to the top


40




a


. The relay unit


52


communicates a sheet discharge section


46


having a sheet outlet


46




a


to the sorter


50


. A manual feed unit


54


is positioned below the duplex copy unit


48


.




The duplex copy unit


48


, sorter


50


and manual feed unit


54


are distributed to both sides of the apparatus


40


, as stated above. This allows the top


40




a


of the apparatus body


40


A to be effectively used without obstructing the removal of a jamming sheet from the duplex copy unit


48


or the duplex copying operation.




As

FIG. 3

indicates, the major constituents of the apparatus


40


concentrate at one side due to the substantially vertical transport path SP


1


. Therefore, the central part of the apparatus


40


, i.e., the space below the top


40




a


is broad. For this reason, in the illustrative embodiment, the top


40




a


is positioned at a level lower than a preselected level, i.e., the level of a conventional apparatus having major units arranged around its center, while maintaining the discharge section


46


at the conventional level. The relay unit


52


is arranged in a recess


56


between the discharge section


46


and the top


40




a


. The top of the relay unit


52


is flush with the top of the discharge section


46


, i.e., the top of the apparatus


40


. The sheet outlet


46




a


is substantially aligned with a sheet transport path SP


2


defined in the relay unit


52


.




As stated above, the relay unit


52


can be arranged while maintaining the discharge section


46


at the conventional level, i.e., without increasing the overall height of the apparatus


40


. Because the sheet outlet


46




a


is substantially aligned with the path SP


2


of the relay unit


52


, the sheet transport distance is minimized.




It is to be noted that the relay unit


52


is similarly applicable even to the apparatus of the type having major units arranged around its center, if desired.




In operation, a sheet fed from a tray


58


included in the sheet feed section


44


by feed rollers


60


is conveyed to a registration roller pair


62


by conveyor rollers, or conveying means, arranged along the path SP


1


. The registration roller pair


66


drives the sheet S toward an image transfer position


68


in synchronism with the movement of a toner image formed on a photoconductive drum


66


, as stated earlier. The toner image is transferred from the drum


66


to the sheet S at the position


68


. The sheet S with the toner image is conveyed to a fixing unit


70


. After the toner image has been fixed on the sheet S, the sheet S is brought to the sheet discharge section


46


.




In a duplex copy mode, the sheet S carrying the toner image on one side thereof is switched back by use of the upper portion of the apparatus body


40


A, i.e., the internal structure of the relay unit


52


. Then, the sheet S is routed through a duplex copy path


72


joining in the path SP


1


at a position upstream of the registration roller pair


62


. A sheet fed from the manual feed unit


54


is brought to the path SP


1


by a group of rollers


74


. The path SP


2


of the relay unit


52


is an extension of the path SP


1


. Conveying means including conveyor rollers


76


is arranged in the relay unit


52


. In this sense, the path SP


2


is equivalent to the path P


1


as to function. The sheet S coming out of the fixing unit


70


is transferred to the sorter


50


by way of the discharge section


46


and relay unit


52


.




The relay unit


52


makes it needless to add the sorter


50


or similar finishing device in the direction of height of the apparatus body


40


A, promoting the free layout of the finisher. This prevents easy operation from being obstructed by the increase in the height of the apparatus, and obviates the limitations on the number of bins and the number of sheets to be stacked.




While the illustrative embodiment has concentrated on the sorter


50


, it is similarly practicable with a mail box, sorter/stapler or similar finisher.




2nd Embodiment





FIG. 4

shows a second embodiment of the present invention. In this embodiment, the same or similar structural elements as or to the elements of the first embodiment are designated by the same reference numerals, and a detailed description will not be made in order to avoid redundancy. A s shown, the second embodiment includes a relay unit


82


having at least one tray, four trays


88




a


-


88




d


by way of example. Discharge rollers


86




a


-


86




d


and path selectors


88




a


-


88




d


are respectively associated with the he trays


83




a


-


84




d


. With this configuration, the relay unit


82


plays the role of a mail box, sorter, or similar unit for sorting or stacking sheets. The trays


84




a


-


84




d


may be used in combination with the sorter


50


for sorting or stacking sheets sequentially transferred from the sheet discharge section


46


.




As shown in

FIG. 5

, a tray


90


may be positioned downstream of the relay unit


82


with respect to the direction of sheet transport so as to operate in combination with the trays


84




a


-


84




d.






As stated above, the relay unit


82


extending substantially parallel to the top of the apparatus body, labeled


80


A, is capable of serving as finishing means alone. Therefore, even when the number of trays is increases, the increase of the height of the apparatus remains constant and is minimized. Further, the relay unit or finishing means


82


can coexist with another or other finishers without increasing the height of the apparatus. In addition, the usual sheet discharge and the sheet discharge to the finisher share a single path, so that the path is simple.




In the embodiment, sheets are usually driven out to the most upstream tray, i.e., tray


84




a


in order to prevent the advantages of the substantially vertically path from being lessened.




Assume that the first or the second embodiment switches back the sheet within the relay unit


52


or


82


in the duplex copy mode. Then, the entire conveying means arranged in the relay unit


52


or


82


must be provided with a reversible rotating function. Such an arrangement would increase the cost and deteriorate reliability of transport. In light of this, as shown in

FIG. 6

, path selecting means


92


may be positioned just after the sheet discharge section


46


while another switch-back path may be defined in the relay unit


82


. In

FIG. 6

, the top


80




a


of the apparatus body


80


A bifunctions as a tray and a switchback path SB at the same time. This eliminates the need for an additional switch-back path which would complicate the construction.




The first and second embodiments described above have the following unprecedented advantages.




(1) A relay unit is mounted on the top of an apparatus and arranged in the horizontal direction, allowing finisher or the lie to be added to the side of the apparatus. The finisher can be added without lessening the advantages of a substantially vertical sheet transport path, e.g., easy removal of a jamming sheet.




(2) The top of the apparatus is so lowered as to accommodate the relay unit in a compact configuration while maintaining a sheet discharge section at the conventional level, taking advantage of the characteristic structure of the substantially vertical path. The relay unit therefore does not increase the dimensions of the apparatus.




(3) A sheet outlet included in the sheet discharge section is substantially aligned with a sheet transport path defined in the relay unit. This minimizes the sheet transport distance to, e.g., finisher.




(4) Because the relay unit is capable of sorting or stacking sheets alone, it can be implemented as finishing means itself and can further enhance a multifunction configuration.




(5) An additional switch-back path is formed in the relay unit and makes it needless for the entire conveying means of the relay unit to have a reversible rotating function.




(6) The switch-back path is implemented by the top of the apparatus playing the role of a tray. Therefore, a sheet can be easily switched back without resorting to any additional construction.




3rd Embodiment




Reference will be made to

FIGS. 7-10

for describing a third embodiment of the present invention. As shown in

FIG. 7

, an image forming apparatus


100


includes a body


100


A accommodating an image forming section


106


. The image forming section


106


includes a photoconductive drum


105


. A sheet feed section


108


is positioned below the section


106


while a fixing section


109


and a sheet discharge section


110


are positioned above the section


106


. A writing unit and other conventional units are not shown because they are not relevant to the understanding of this embodiment. A mail box or sheet receiving means is mounted on the top of the sheet discharge section


110


and has one or more trays. A sorter, sorter/stapler or similar finisher


114


is mounted on one side of the apparatus body


100


A in order to deal with sheets coming out of the body


100


A. A relay unit


116


is also mounted on the top of the apparatus body


100


A and communicates the sheet discharge section


110


and finisher


114


. A usual sheet discharge section


118


is formed integrally with the relay unit


116


. The relay unit


116


plays the role of a single bin or tray and has its own sheet transport path and conveying function arranged thereinside. The sheet feed section


108


has a plurality of cassettes


108




a


-


108




d


each storing a stack of sheets


20


of particular size.




The transport path SP extends substantially vertically from the sheet feed section


108


to the sheet discharge section


110


via the image forming section


106


. The major process units of the image forming section


106


, as well as the sheet feed section


108


, are built in the apparatus body


100


A. The sheet path SP is almost fully exposed to the outside only if the side of the apparatus body


100


A is opened, promoting easy jam processing.




A sheet S of desired size is fed from the sheet feed section


108


to a registration roller pair


124


, and therefrom to the image forming section


106


. A toner image is transferred from the drum


105


to the sheet S at an image transfer position, not shown. The sheet S with the toner image is conveyed to the fixing unit


109


by a conveyor device


126


arranged along the sheet path SP. The sheet S coming out of the fixing unit


109


is steered to the usual discharge path


118


by, e.g., a path selector


128


(path SPa) and laid on the top of the apparatus body


100


A (transport cover


138


which will be described), or steered to the mail box


112


(path SPb), or steered to the relay unit


116


(path SPc). The path SPc terminates at the finisher


114


. In the duplex copy mode, the sheet S carrying the image on one side thereof is switched back from the usual sheet feed section


118


into a path SPd formed in a duplex copy unit, not shown. As a result, the sheet S turned upside down is again brought to the path SP.




In the illustrative embodiments, the mail box


112


has at least four bins or trays


130




a


-


130




d


. At least the tray


130


closest to the relay unit


116


is mounted on the body, not shown, of the mail box


112


in such a manner as to be rotatable up and down (direction E). Specifically, as shown in

FIG. 8

, the tray


130




a


has a shaft


132


journalled to brackets


134


included in the body of the mail box


112


. A stop


136


is affixed to one side of the tray


130




a


adjacent to the shaft


132


. When the stop


136


abuts against the bracket


134


adjacent thereto, it limits the downward movement of the tray


130




a


(lower limit).




As shown in

FIG. 7

, the transport cover


138


mentioned earlier is rotatable up and down about a shaft


140


. When the cover


138


is rotated upward, the path SPc is exposed to the outside and facilitates the removal of a jamming sheet. At the same time, the cover


138


plays the role of a tray associated with the usual sheet discharge section


118


. An auxiliary tray


142


is contiguous with the outermost end of the cover


138


. A discharge cover


144


rotatable up and down about a shaft


146


is included in the usual discharge section


118


. By raising the discharge cover


144


, it is possible to uncover the path SPa in order to remove a jamming sheet.




In the embodiment, the mail box or sheet receiving means


112


having one or more trays is mounted on the top of the apparatus body


100


A. In this case, to reduce the overall height of the apparatus as far as possible (for easy operation), it is necessary to reduce the space between the top of the apparatus body


100


A, i.e., relay unit


116


and the bottom tray


130




a


of the mail box


112


as far as possible. When the cover


138


of the relay unit


116


is raised or opened, it tray


130




a


interferes with the cover


138


.




However, because the tray


130




a


is rotatable up and down, the cover


138


abutting against the tray


130




a


cause the tray


130




a


to rotate upward (retract), as shown in FIG.


9


. Consequently, the cover


138


can be sufficiently raised and provides a space broad enough to promote easy removal of a jamming sheet. After the jam processing, only if the cover


138


is lowered, the tray


130




a


is automatically lowered to its preselected position due to its own weight. If the retraction of the tray


130




a


does not suffice, the tray


103




b


overlying the tray


130




a


may also be rotatably supported.




As shown in

FIG. 10

, when the discharge cover


144


of the usual sheet discharge section


118


is opened for removing a jamming sheet, the tray


130




a


is also raised to form a sufficient working space.




4th Embodiment





FIGS. 11 and 12

show a fourth embodiment of the present invention. In this embodiment, the same or similar structural elements as or to the elements of the third embodiment are designated by the same reference numerals, a detailed description thereof will not be described in order to avoid redundancy. As shown, an image forming apparatus


200


is characterized in that the tray


130




a


is rotatable in synchronism with the transport cover


138


. Specifically, the shaft


132


of the tray


130




a


has one end thereof removed, as at


132




a


. A toothed pulley


148


has a hole


148




a


identical in cross-section as the removed portion


132




a


of the shaft


132


, and is affixed to the removed portion


132




a


. Likewise, a toothed pulley


148


is affixed to a removed portion


140




a


included in the shaft


140


of the transport cover


138


. A timing belt


150


having a toothed inner periphery is passed over the toothed pulleys


148


. The trays other than the tray


130




a


are freely rotatable, as in the third embodiment.




As shown in

FIG. 12

, when the cover


138


of the relay unit


116


is opened, the tray


130




a


is also rotated upward via the timing belt


150


. As a result, a sufficient working space is available above the cover transport


138


, facilitating the removal of a jamming sheet. In addition, because the tray


130




a


does not abut against the cover


138


, it is not necessary for the operator to raise the tray


130




a.






If desired, the discharge cover


144


and tray


130


may be interlocked in the same manner as the transport cover


138


and tray


130




a


. Alternatively an arrangement may be made such that when one of the covers


138


and


144


is opened, the tray


130




a


rotates in interlocked relation thereto. The toothed pulleys


148


and timing belt


150


may be replaced with a gear and rack device, linkage, etc.




5th Embodiment




Reference will be made to

FIGS. 13-17

for describing a fifth embodiment of the present invention. In this embodiment, the same or similar structural elements as or to the elements of the third and fourth embodiments are designated by the sane reference numerals, and a detailed description thereof will not be made in order to avoid redundancy. As shown in

FIG. 13

, an image forming apparatus


300


includes a movable relay unit


152


mounted on the top thereof. The usual sheet discharge section


118


is formed integrally with the tray unit


152


. A scanner or image reading device


156


is mounted on the apparatus


300


above the relay unit


152


by a frame


154


. The space between the relay unit


152


and the scanner


156


is reduced as far as possible in order to prevent the operation surface of the scanner


156


from being increased in level.





FIG. 14

shows another image forming apparatus


301


also representative of the illustrative embodiment. As shown, a relay unit


158


having the usual sheet discharge section


118


integrally therewith is mounted on the top of the apparatus


301


. The mail box


112


having four bins or trays is positioned above the sheet discharge section


110


. In this embodiment, the tray


130




a


is not rotatable.




As shown in

FIG. 15

, the movable relay unit


152


or


158


(partly omitted) is slidably supported by guide rails


160


and


162


. The guide rail


160


is affixed to the bottom of a recess


104




b


located at the top of an apparatus body


300


A or


301


A while the guide rail


162


is affixed to one side wall of the recess


104




b


. The operator may pull the relay unit


152


or


158


toward the operator, gripping a handle


164


. When the relay unit


152


or


158


is pushed to a preselected mounting position, rollers


166


built in the apparatus body


300


A or


301


A and rollers


168


built in the usual discharge section


118


face each other. In this condition, the sheet S is driven out onto the transport over


138


. The covers


138


and


144


are constructed in the same manner as in the previous embodiments




As shown in

FIG. 16

, when the operator pulls the relay unit


152


toward the operator and then opens the transport cover


138


in the direction indicated by an arrow, the scanner


156


and cover


138


are prevented from interfering with each other. This guarantees a sufficient working space at the time of removal of a jamming sheet. As shown in

FIG. 17

, to remove a sheet jamming the usual sheet discharge section


118


, the relay unit


152


is also pulled toward the operator, and then the discharge cover


144


is opened. This reduces the space between the scanner


156


and the relay unit


152


as far as possible, and obviates awkward operation ascribable to the excessive height of the apparatus. Moreover, the cover transport


138


plays the role of a tray for the usual sheet discharge section


118


at the same time, simplifying the arrangement of the upper portion of the apparatus.




6th Embodiment





FIGS. 18-21

show a sixth embodiment of the present invention. In this embodiment, the same or similar structural elements as or to the elements of the previous embodiments are designated by the same reference numerals, and a detailed description thereof will not be made in order to avoid redundancy. As shown, an image forming apparatus


400


includes a body


400


A accommodating a relay unit


170


at the center thereof. A scanner or image reading device


156


is mounted on the apparatus body


400


A above the relay unit


170


via spacers


172


and


174


.




The relay unit


170


has a usual sheet discharge section


176


integrally therewith. The sheet is transferred from the discharge section


110


of the apparatus body


400


A to a usual discharge section


176


by way of a transfer section


178


. A path selector or path selecting means


177


disposed in the sheet discharge section


176


steers the sheet toward the finisher


114


or causes it to be driven out via the sheet discharge section


176


. The portion of the relay unit


170


adjoining the finisher


114


has a transport cover


182


for stacking sheets driven out of the usual discharge section


176


, a transport path


180


for guiding the sheet from the path selector


177


to the downstream side and including a guide


186


, and conveyor roller pairs


183


,


184


and


185


.




The transport cover


182


is divided into two cover parts


188


and


190


in the direction of sheet transport. The cover part


188


adjacent to the usual discharge section


176


has its rear end in the direction of sheet transport supported by a shaft


191


, and is rotatable up and down about the shaft


191


. The other cover part


190


adjacent to the finisher


114


has its front end in the above direction supported by a shaft


192


, and is also rotatable up and down about the shaft


192


. The upper surface of the transport cover


182


is used to stack sheets in the usual sheet discharge mode.




The usual discharge section


176


has a discharge roller pair


194


a discharge cover


195


carrying the upper roller of the roller pair


194


therewith, a guide


197


forming a sheet discharge path


196


between it and the discharge cover


195


, and a solenoid or drive means


198


for driving the path selector


177


. The cover


195


is supported by a shaft


193


at its side remote from the transfer section


178


and rotatable up and down. The solenoid


198


is affixed to the cover discharge


195


.




As shown in

FIG. 19

, the path selector


177


has a shaft


177




a


with which an arm


201


is formed integrally. One end


201




a


of the arm


201


is engaged with a plunger


198




a


extending from the solenoid


198


. A spring


202


is anchored to the other end


201




b


of the arm


201


. In this condition, the path selector


177


is constantly biased toward a position where it steers sheets toward the finisher


114


, as indicated by a solid line. In the usual sheet discharge mode, the solenoid


198


is turned on to switch the path selector


177


to a position indicated by a dash-and-dots line.




Assume that a sheet has jammed the path


180


. Then, as shown in

FIG. 20

, the operator raises one or both of the cover parts


188


and


190


in order to uncover the path


180


. If the transport cover


182


is implemented as a single member, then the maximum angle to which the cover


182


can be opened is only θ. The resulting space is too narrow for the operator to access the path


180


, and in addition different in opening degree in the right-and-left direction. In the illustrative embodiment, the path


180


can be substantially fully opened without interfering with the scanner


156


, facilitating the removal of a jamming sheet. Because the cover parts


188


and


190


separated from each other reduce the length, the spacers


172


and


174


can be reduced in height. This prevents the operation surface of the scanner


156


from increasing in level.




Furthermore, only one of the cover parts


188


and


190


can be opened in order to uncover only a part of the path


180


jammed by a sheet. In this case, because the space above the cover part not opened is available for jam processing, the jam processing can be performed in the same manner as when both the covers


188


and


190


are opened.




While the covers


188


and


190


are openable independently of each other in the above embodiment, one of them may be opened in interlocked relation to the other. The interlocked configuration will facilitate the operation for fully uncovering the path


180


.




The opening/closing structure of the cover


195


included in the usual sheet discharge section


176


stems from the fact that sheet jams are likely to occur at the transfer section


178


.




As shown in

FIG. 21

, when a jam occurs during usual sheet discharge, the discharge cover


195


is rotated upward so as to substantially fully uncover the path


196


and transfer section


178


. Should the fulcrum about which the cover


195


is rotatable be located at the transfer section


178


side, it would be difficult to remove a sheet jamming the transfer section


178


. In this embodiment, the transfer section


178


can be fully uncovered, facilitating jam processing.




The path selector


177


is mounted on the cover


195


via the solenoid


198


. Therefore, the path selector


177


adjacent to the transfer section


178


moves in interlocked relation to the discharge cover


195


, further increasing the space available for the removal of a jamming sheet.




Because the solenoid


198


for driving the path selector


177


is supported by the cover


195


, an extra frame for a mechanism for switching the path selector


177


is not necessary. This successfully reduces the number of parts, and therefore the cost.




7th Embodiment





FIGS. 22-24

show a seventh embodiment of the present invention. In this embodiment, the same or similar structural elements as or to the elements of the previous embodiments are designated by the same reference numerals. As shown in

FIG. 22

, an image forming apparatus


500


includes a body


500


A. A relay unit


205


is mounted on the top of the apparatus body


500


A. The scanner


156


is mounted on the apparatus body


500


A above the relay unit


205


via the spacers


172


and


174


. The relay unit


205


includes a usual sheet discharge section


206


having a discharge cover


207


. The discharge cover


207


is rotatable about a fulcrum located at the transfer section


178


side, as in the above embodiment.




A transport cover


210


included in the relay unit


205


consists of three cover parts


211


,


212


and


213


separate in the direction of sheet feed. The cover part


211


adjacent to the usual sheet discharge section


206


is supported by a shaft


214


at its rear end in the direction of sheet transport. Further, the cover part


213


adjoining the finisher


114


is supported by a shaft


215


at its front end in the direction of sheet transport. The cover parts


211


and


213


are therefore rotatable up and down. The intermediate cover part


212


is fixed in place and has a length L smaller than the minimum sheet size as measured in the direction of sheet feed in the relay unit


205


.




As shown in

FIG. 23

, when the sheet S jams the path


180


, one or both of the cover parts


211


and


213


are rotated upward in order to partly uncover the path


180


. Even if the sheet S stops below the intermediate fixed cover part


212


it can be easily removed because its leading edge or trailing edge protrudes from the cover part


212


.




The length of the cover parts


211


and


213


is further reduced, compared to the two cover part configuration. This allows the level of the spacers


172


and


174


to be further lowered and prevents the operation of the scanner


156


from rising in level. Stated another way, the compact configuration of the cover guarantees a broad space for jam processing even when the space available between the apparatus body


500


A and the scanner


156


is narrow.




As shown in

FIG. 24

, the scanner


156


and finisher


114


may be respectively replaced with a bin or sheet receiving means


216


having one or more bins and a tray


217


. Such an alternative configuration, like the above configuration, facilitates easy removal of a jamming sheet.




8th Embodiment




Referring to

FIGS. 25-27

, an eighth embodiment of the present invention will be described. In this embodiment, the same or similar structural elements as or to the elements of the previous embodiments are designated by the same reference numerals. As shown in

FIG. 25

, an image forming apparatus


500


includes a body


600


A on which a relay unit


220


is mounted. The scanner


156


is mounted on the apparatus body


600


A above the relay unit


220


via a spacer


172


and a one-bin device


221


. The one-bin device, or sheet receiving means,


221


is positioned above the sheet feed section


110


and has one or more bins. A usual sheet discharge section


222


is constructed integrally with a part of the relay unit


220


positioned above the sheet discharge section


110


. The usual sheet discharge section


222


includes a discharge cover


223


rotatable up and down. Specifically, the discharge cover


223


has its end remote from the transfer section rotatably supported by a shaft


193


, as in the sixth embodiment shown in FIG.


18


.




The one-bin device


221


has a body


224


and a bin or tray


225


. A sheet transport path


226


is formed in the body


224


and communicated to the path


110




a


extending upward from the sheet feed section


110


. A conveyor roller pair


227


and a discharge roller pair


228


are mounted on the body


224


. In the illustrative embodiment, the tray


225


of the one-bin device


221


directly serves as the lowermost tray. However, when a mail box having a plurality of trays is mounted on the apparatus body


600


A, its lowermost tray will be affixed to the discharge cover


223


.




The tray


225


is divided into a stationary portion


229


formed integrally with the lower portion of the body


224


, and a movable portion


230


mounted on the discharge cover


223


. Specifically, as shown in

FIG. 27

, a tray bracket


232


is fastened to the top of the cover


223


by screws


231


. The movable portion


230


is mounted to the cover


223


via the tray bracket


232


.




Stub shafts


233


protrude from the opposite ends of the tray bracket


232


while holes


234


are formed in the rear end of the movable portion


230


with respect to the direction of discharge. After the holes


234


have been engaged with the stub shafts


233


, the bracket


232


is stopped by a stop ring


235


. In this condition, the movable portion


230


is rotatable up and down relative to the discharge cover


223


while being prevented from slipping out. A leg


236


extends downward from the bottom of one side of the movable portion


230


. The leg


236


slides on a channel or rail


237


formed on the top of the apparatus. When the movable portion


230


moves substantially horizontally, the leg


236


serves to maintain the position of the portion


230


.




As shown in

FIG. 25

, when the discharge cover


223


is not open, the stationary portion


229


and movable portion


230


of the tray


225


are contiguous with each other. In this condition, the sheet S has its rear end portion positioned by the stationary portion


229


and has its other portion laid on the movable portion


230


.




Assume that a sheet J jams the transfer section


178


between the relay unit


220


and the sheet discharge section


110


. Then, as shown in

FIG. 26

, the operator raises the discharge cover


223


in the direction indicated by an arrow, uncovering the transfer section


178


. At this instant, the movable portion


230


of the tray


225


moves substantially horizontally while slightly moving up and down, in interlocked relation to the cover


223


. Because the position of the movable portion


230


is maintained by the leg


236


, the sheets S stacked on the movable portion


230


are prevented from being dislocated. In addition, when the cover


223


is closed, it is prevented from contacting and damaging the rear end of the sheet stack.




The stationary portion


229


of the tray


225


has a length d, as measured in the direction of sheet discharge, selected such that the portion


229


does not protrude horizontally into the space above the transfer portion


178


when the discharge cover


223


is opened. This prevents the portion


229


from obstructing jam processing.




If the tray


225


is implemented as a single member, then the portion corresponding to the stationary portion


229


will remain above the transfer section


178


when the discharge cover


223


is opened, obstructing jam processing. This embodiment with the above configuration eliminates this problem and allows the jamming sheet J to be removed with ease.




The ratio between the stationary portion


229


and the movable portion


230


with respect to the length in the direction of sheet discharge is selected such than when the discharge cover


223


is opened, the sheet remains on the portion


230


due to friction derived from its own weight. Therefore, the sheet remains on the movable portion


230


without fail during movement of the portion


230


.




As shown in

FIG. 25

, the apparatus


600


has three different sheet outlets, i.e., an output A for discharging the sheet to the tray


125


, an outlet B for discharging it the top of the relay unit


220


, and an outlet C for discharging it to the tray


114




a


of the finisher


114


. Therefore, when the apparatus


600


is implemented as a multifunction machine having the functions of a copier, facsimile apparatus and printer, the three outlets A-C can be selectively used. This surely prevents sheets output by one function from being mixed with sheets output by another function.




The tray or lowermost tray


225


of the one-bin device


221


located above the sheet discharge section


110


is movable together with the discharge cover


223


, as stated earlier. This obviates the above mixture of sheets output by different functions while insuring easy jam processing.




The third to eighth embodiments shown and described have the following various advantages.




(1) A mail box or similar sheet receiving device positioned above and in close proximity to a relay unit has a rotatable tray. Therefore, when a cover is opened in order to remove a sheet jamming the relay unit, the tray retracts in accordance with the opening of the cover and provides a sufficient space for the removal of the sheet. It is possible to make the most of the merits of the coexistence of finishers implemented by the relay unit.




(2) The tray rotates in interlocked relation to the opening of the cover. This further broadens the space available for jam processing and thereby facilitates the operator's manipulation, while making it needless for the operator to raise the tray.




(3) The relay unit can be pulled out toward the operator. This prevents the relay unit from interfering with a scanner or a mail box mounted on the apparatus, and guarantees a sufficient space for jam processing. Further, the distance between the scanner, mail box or the like and the relay unit can be reduced as far as possible, preventing the height of the apparatus from increasing.




(4) A transport cover included in the relay unit consists of a plurality of cover parts separate in the direction of sheet transport. At least one of the cover parts is supported by a shaft at one end thereof so as to be rotatable up and down. The transport cover can therefore be widely opened and facilitates the removal of a jamming sheet. Because the individual cover part is compact, it rotates with only a small radius and prevents the operation surface of a scanner from increasing in level.




(5) The cover consists of three parts separated from each other, and only the intermediate cover part is fixed in place. This makes the configuration of the cover parts further compact and obviates the increase in the level of the operation surface of the scanner more positively. As a result, the entire apparatus is provided with a compact configuration.




(6) The intermediate or stationary cover part has a length smaller than the minimize sheet size as measured in the direction of sheet transport. Therefore, even when a sheet stops a path below the cover, its leading edge or trailing edge protrudes from the cover part and can be pulled out with ease.




(7) The relay unit includes a usual sheet discharge section having a discharge cover. The discharge cover is movable up and down about a fulcrum located at the opposite side to a transfer section intervening between the relay unit and the apparatus body. Therefore, the transfer section where a sheet jam is most likely to occur can be uncovered, further promoting easy removal of a jamming sheet.




(8) A path selector is supported by the discharge cover and therefore moves when the cover is opened. This further facilitates the removal of a jamming sheet.




(9) Drive means for driving the path selector is also supported by the discharge cover. This makes it needless to provide a frame or the like for a mechanism which actuates the path selector, thereby reducing the number of parts and the cost.




(10) A sheet receiving device having one or more bins is located above a sheet discharge section and has its lowermost tray constructed integrally with the discharge cover of the usual sheet discharge section. In this configuration, the lowermost tray is movable in interlocked relation to the opening of the discharge cover. This prevents the lowermost tray from obstructing the removal of a jamming sheet. As a result, the number of sheet outlets, i.e., the number of functions available with the apparatus can be increased without effecting the easy removal of a jamming sheet.




(11) The lowermost tray is movable substantially horizontally in unison with the rotation of the discharge cover. This prevents sheets stacked on the tray from being dislocated during the movement of the tray.




(12) The lowermost tray consists of a stationary portion and a movable portion. The stationary portion has a length selected such that it does not protrude horizontally to above a space available when the discharge cover is opened. Therefore, a jamming sheet can be removed as easily as when the lowermost tray is absent.




(13) The stationary portion and movable portion of the lowermost tray are provided with such a ratio that the sheet remains on the movable portion due to its own weight when the discharge cover is opened. The sheet is therefore prevented from being dislocated due to friction acting between it and the stationary portion during the movement of the movable portion.




9th Embodiment




Referring to

FIGS. 28-33

, a ninth embodiment of the present invention will be described. As shown in

FIG. 28

, an image forming apparatus


700


includes a body


700


A accommodating an image forming section


302


. A sheet feed section


304


and a sheet discharge section


306


are located below and above the image forming section


302


, respectively. A scanner


312


is mounted on the apparatus body


700


A above the sheet discharge section


306


via spacers


308


and


310


. A sorter, sorter/stapler or similar finisher


314


is mounted on one side of the apparatus body


700


A and includes a stack portion


314




a


. A relay unit


316


is mounted on the top of the apparatus body


700


A and has its own sheet transport path and conveying function arranged along the top of the apparatus body


700


A. The sheet feed section


308


includes a plurality of cassettes


318


and


320


respectively loaded with sheets S


1


and S


2


of, e.g., different sizes. The transport path SP extends substantially vertically from the sheet feed section


304


to the sheet discharge section


306


via the image forming section


302


.




The image forming section


302


includes an image carrier implemented as a drum


322


rotatable counterclockwise, as viewed in FIG.


28


. An optical writing unit


324


electrostatically forms a latent image on the drum


322


. Arranged around the drum


322


are a main charger


326


for uniformly charging the drum


322


, an eraser, not shown, for erasing charge deposited on a non-image area, a developing unit


328


for transforming the latent image to a toner image, an image transfer device


330


for transferring the toner image from the drum


322


to a sheet while conveying the sheet, a cleaning unit


322


for removing toner remaining on the drum


322


after the image transfer, and a discharger, not shown, for dissipating the charge also remaining on the drum


322


after the image transfer. A fixing unit


334


is positioned between the image transfer device


330


and the sheet discharge section


306


. The fixing unit


334


fixes the toner image transferred to the sheet by heat and pressure.




The optical writing unit


324


transforms image data output from the scanner


312


to an optical signal, and writes a latent image representative of a document image on the drum


322


. The writing unit


324


may write a latent image in accordance with image data output from a personal computer. The writing unit


324


scans the surface of the drum


322


with a laser beam issuing from a laser. Specifically, the laser is steered by a conventional polygonal mirror and then routed through a mirror and fθ lens to the drum


322


.




A sheet S


1


or S


2


is fed by a pick-up roller


336


while being separated by the underlying sheets by a separator roller pair


338


. Then, the sheet S


1


or S


2


is conveyed by a conveyor roller pair


340


along the substantially vertical path SP. A registration roller pair


342


precedes the image transfer device


330


in the direction of sheet transport. The roller pair


342


drives the sheet S


1


or S


2


at a predetermined timing to a nip between the image transfer device


330


and the drum


322


. A sheet sensor


344


precedes the registration roller pair


342


in the above direction.




The sheet discharge section


306


includes a discharge roller


346


. A sheet discharge sensor


348


precedes the discharge roller pair


346


and is the most downstream sensor with respect to the vertical path SP.




The scanner


312


includes a glass platen


350


for laying a document thereon. A cover plate


352


presses the document against the glass platen


350


and has a white pressing surface. A lamp


354


illuminates the document laid on the glass platen


350


. The resulting reflection from the document is reflected by a mirror


356


. A pair of mirrors


358




a


and


358




b


are movable at one half of the speed of the mirror


356


. A lens


360


and a CCD (Charge Coupled Device) image sensor


362


are also arranged in the scanner


312


.




The major process units of the image forming section


302


, the sheet feed section


304


and the sheet discharge section


306


are accommodated in the apparatus body


700


A. The substantially vertical sheet path SP is almost fully exposed to the outside only if a side wall


700




a


forming part of the apparatus body


700


A is opened. This promotes easy removal of a sheet jamming the path SP.




The relay unit


316


includes a stack section


364


for stacking sheets carrying images thereon and sequentially driven out via the sheet discharge section


306


. A conveying device


366


conveys the sheet from the discharge section


306


to the stack section


364


while a conveying device


368


conveys the sheet toward the finisher


314


. A path selector


370


steers the sheet coming out of the discharge section


306


toward the stack section


364


or the finisher


314


. A controller


372


(see

FIG. 29

) controls the path selector


370


. A full-stack sensor or full-stack sensing means


374


is associated with the stack section


364


in order to sense the full condition of the section


364


.




The finisher


368


includes a sheet path SPb connecting the discharge section


306


and finisher


314


, roller pairs


378


and


380


, an outlet roller pair


382


located downstream of the roller pair


380


for discharging the sheet to the finisher


314


, and a sheet sensor


384


intervening between the roller pairs


378


and


380


. Another full-stack sensor


384


is associated with the stack portion


304




a


of the finisher


314


. The path selector


370


consists of a switching member


370




a


and a solenoid


370




b


(see

FIG. 29

) for driving it.




The controller


372


is implemented as a microcomputer. As shown in

FIG. 29

, the outputs of various sensors including the sheet discharge sensor


348


and full-stack sensors


374


and


384


are input to the controller


372


. In response, the controller


372


selectively turns on or turns off the solenoid


370




b


. An operation panel


386


is also connected to the controller


372


and allows processing using the finisher


314


to be input thereon.




In operation, the main charger


326


charges the surface of the drum


322


uniformly. The writing unit


324


scans the charged surface of the drum


322


with a laser beam in accordance with the image data output from the scanner


312


or from a personal computer, thereby forming a latent image on the drum


322


. After the eraser has erased the charge of the non-image area of the drum


322


, the developing unit


328


develops the latent image with charged toner so as to produce a corresponding toner image. The sheet S


1


, for example, is fed from the cassette


318


by the pick-up roller


336


, separated from the others by the separator roller pair


338


, and fed into the sheet path SP. The registration roller pair


342


drives the sheet S


1


toward the image transfer device


330


such that the leading edge of the sheet meets that of the toner image of the drum


322


at the nip between the drum


322


and a belt included in the device


330


. The sheet S


1


carrying the toner image thereon is brought to the fixing unit


334


to have the toner image fixed thereby, as mentioned earlier.




Assume that a mode not needing the finisher


314


is selected. Then, as shown in

FIG. 30

, the controller


372


turns on the solenoid


370




b


in order to move the switching member


370


to its lowered position. As a result, only the sheet path SPa of the conveying device


366


is unblocked. In this condition, the sheet S


1


driven out via the discharge section


306


is conveyed by the conveying device


366


to the stack section


364


. Let this sheet discharge be referred to as usual discharge.




On the other hand, assume that a mode needing the finisher


314


, e.g., a staple mode is selected. Then, as shown in

FIG. 31

, the controller


372


does not turn on the solenoid


370


and thereby maintains only the sheet path SPb terminating at the finisher


368


open. As a result, the sheet S


1


come out of the discharge section


306


is conveyed by the conveying device


368


to the finisher


314


. The sheet S


1


is subjected to stapling or similar job in the finisher


314


, and then driven out to the stack section


304




a


, although not shown specifically.




Of course, the sheet S


1


may be discharged to tie stack section


304




a


of the finisher


314


by the usual discharge. However, in the illustrative embodiment, the sheet S


1


is delivered to the stack section


364


in order to reduce the so-called first copy time, so long as finishing is not necessary.




Why the solenoid


370




b


is held in its OFF state for maintaining the conveying device


368


assigned to the finisher


314


unblocked is as follows. Generally, a greater number of sheets are stacked on the finisher than on the stack section


364


, so that continuous sheet feed occurs over a long period of time. In light of this, the embodiment reduces the duty of the solenoid


370




b


so as to reduce the size and cost of the solenoid


370




b.






The finisher


314


has a stapling function thereinside, although not shown.




The relation between the stacking function and the full-stack sensor


374


will be described hereinafter. Assume that the mode not needing the finisher


314


is selected, and that a job exceeding the number of sheets which can be stacked on the stack section


364


of the relay unit


316


is executed. Then, as shown in

FIG. 32

, the controller


372


turns off the solenoid


370




b


in response to the output of the full-stack sensor


374


. As a result, the conveying device


368


assigned to the finisher


314


is selected. Therefore, images can be continuously formed on the number of sheets available with the relay unit


316


and the number of sheets available with the finisher


314


. When the stack section


304




a


of the finisher


314


is full, as determined by the full-stack sensor


384


, the above switching operation may not be effected.





FIG. 33

is a flowchart demonstrating the above operation of the controller


372


. As shown, the controller


372


turns on the solenoid


370




b


in response to the output of the sheet discharge sensor


348


located at the downstream end of the sheet path SP.




The full-stack sensor


374


may include an arm to be rotated by the sheet being discharged, and sense the full condition on the basis of the position to which the arm returns. This kind of sensor is taught in, e.g., Japanese Patent Laid-Open Publication No. 4-280774.




As stated above, the finisher


314


is mounted on the apparatus body


700


A in such a manner as not to increase the height or the weight of the body


700


A. The relay unit


316


extending along the top of the apparatus body


700


A communicates the sheet discharge section


306


to the finisher


314


. This allows the finisher


314


to be used without lessening the advantages of the substantially vertical path SP.




As described above, the ninth embodiment has the following advantages.




(1) A relay unit extends along the top of an image forming apparatus and communicates a sheet discharge section of the apparatus to a finisher. In the relay unit, the usual sheet discharge and the transport to the finisher are selectively effected, depending on an operation mode selected. Therefore, the finisher can be used without lessening the advantages of a substantially vertical sheet transport path. When finishing is not necessary, sheets are delivered to a stack section included in the relay unit so as to reduce the first copy time.




(2) A sheet path terminating at the finisher is unblocked when path selecting means is turned off. This reduces the size and cost of a drive source for driving the path selecting means.




(3) When the output of full-stack sensing means shows that the number of sheets stacked in the relay unit has exceeded the capacity of the relay unit, the finisher is selected automatically. Therefore, images can be formed continuously on a number of sheets exceeding the capacity of the relay unit.




10th Embodiment





FIGS. 34-37

show a tenth embodiment of the present invention. As shown in

FIG. 34

, an image forming apparatus


800


has a sorter, sorter/stapler or similar finisher


402


mounted on one side thereof. The apparatus


800


includes a body


800


A accommodating a plurality of trays


404


loaded with a stack of sheets each, an image forming section


406


for forming a toner image and transferring it to the sheet S fed from any one of the trays


404


, and a fixing unit


408


for fixing the toner image on the sheet S, and so forth. A sheet discharge section


410


for discharging the sheet S and a stack section


412


for stacking the sheet S are located in the upper portion of the apparatus body


800


A. When the finisher


402


is not used, the sheet S driven out via the discharge section


410


is delivered to the stack section


412


.




A relay unit is interposed between the apparatus


800


and the finisher


402


in order to transfer the sheet S driven out via the discharge section


410


to the finisher


402


. The relay unit includes a conveying mechanism


418


and a casing


420


accommodating the mechanism


418


. The conveying mechanism


418


has a plurality of feed roller pairs


414


, a guide


416


, and so forth. The top of the stack section


412


is implemented as a convex inclined surface


422


inclined obliquely downward toward the discharge section


410


. The inclined surface


422


is provided with a plurality of ribs


424


,

FIG. 35

, extending in the direction of sheet discharge.




The bottom of the casing


420


is implemented as a guide surface


426


. When the casing


420


is put on the stack section


412


and then move toward a preselected mounting position, the guide surface


426


slides on the inclined surface


422


. As shown in

FIG. 36

, a plurality of ribs


428


extend on the guide surface


426


in the direction of sheet discharge and are capable of engaging with the ribs


424


. The ribs


424


and


428


are configured such that a pair of ribs


428


at both sides of the paper center contact the side faces of a pair of ribs


424


at both sides of the paper center at their inner side faces.




A pair of positioning pins


430


(only one is visible) are studded on each of the right and left portions of the casing


420


in order to position the casing


420


at the preselected mounting position. Four positioning pins


432


for receiving such positioning pins


430


are formed in the apparatus body


800


A. After the casing


420


has been located at the above position with the pins


430


received in the corresponding holes


432


, a screw


434


is driven into the casing


420


and apparatus body


800


A so as to fasten the former to the latter.




The top of the casing


420


plays the role of a stack section


436


for stacking sheets when the finisher


402


is not used.




Assume that the finisher


402


is mounted to the side of the apparatus


800


. Then, after the casing


420


has been affixed to the apparatus body


800


A, the conveying mechanism


418


arranged in the casing


420


conveys the sheet S driven out via the discharge section


410


to the finisher


402


.




To mount the casing


420


to the apparatus body


800


A, the casing


420


is put on the stack section


412


with its rear face A,

FIG. 35

, contacting the rear face B,

FIG. 35

, of the apparatus body


800


A At this instant, the ribs


428


of the casing


420


and the ribs


424


of the stack section


412


mate with each other with their side faces contacting each other. Subsequently, the casing


420


is moved toward the discharge section


410


along the inclined surface


422


. After the positioning pins


430


have been received in the holes


432


, the casing


420


is fastened to the apparatus body


800


A by the screw


434


, as shown in FIG.


37


.




When the casing


420


is moved toward the position where the pins


430


mate with the holes


432


, the casing


420


move downward along the inclined surface


422


with its guide surface


426


sliding on the surface


422


. Therefore, the casing


420


can be moved to the preselected position without being dislocated. In addition, because the casing


420


moves along the inclined surface


422


, it can be brought to the above position by a minimum of force. The ribs


424


and


420


mating each other prevent the casing from being dislocated in the front-and-rear direction perpendicular to the direction of sheet discharge.




As described above, the tenth embodiment achieves the following unprecedented advantages.




(1) A casing accommodating a sheet conveying mechanism can be mounted to an apparatus body with a guide surface formed on the bottom thereof sliding on a top inclined surface included in a stack section. Therefore, the casing is prevented from being dislocated in the up-and-down direction during its movement. This eliminates the need for exclusive positioning parts.




(2) While the casing is moved toward a preselected position on the apparatus body, an engaging portion formed on the guide surface of the casing and extending in a direction of sheet feed engage with ribs formed on the inclined surface of the stack section. This prevents the casing from being dislocated in the direction perpendicular to the direction of sheet discharge, and also eliminates the need for exclusive positioning parts.




Various modifications will become possible for those skilled in the art after receiving the teachings of the present disclosure without departing from the scope thereof.



Claims
  • 1. An image forming apparatus comprising:a sheet discharge section positioned on one end portion of a top of said apparatus, for allowing a sheet carrying an image thereon and discharged by usual sheet discharge to be stacked on the top of said apparatus via said sheet discharge section; and a relay unit extending horizontally on the top of said apparatus from said sheet discharge section to another end portion which faces the one end portion, comprising a sheet transport path communicable to said sheet discharge section in order to transport said sheet from said sheet discharge section, and conveying means for conveying said sheet substantially horizontally in said sheet transport path.
  • 2. An apparatus as claimed in claim 1, further comprising sheet finishing means located downstream of said relay unit with respect to a direction of sheet transport in said sheet transport path.
  • 3. An apparatus as claimed in claim 1, wherein said relay unit comprises at least one bin.
  • 4. An apparatus as claimed in claim 1, further comprising an image forming section, and a sheet feed section located below said image forming section, wherein the sheet is conveyed from said sheet feed section to said sheet discharge section substantially vertically.
  • 5. An apparatus as claimed in claim 4, further comprising sheet finishing means located downstream of said relay unit with respect to a direction of sheet transport in said sheet transport path.
  • 6. An apparatus as claimed in claim 4, wherein said relay unit comprises at least one bin.
  • 7. An image forming apparatus comprising:a scanner section configured to read image information out of a document; an image forming section configured to form an image on a sheet and arranged below said scanner section thereby forming a space between said scanner section and said image forming section; a sheet discharging section configured to discharge the sheet with the image formed thereon from a first end of said image forming section to said space; a sheet stacking section arranged in said space and configured to stack sheets sequentially discharged from said sheet discharging section; a sheet finishing section adjacent to a second end of said image forming section and configured to finish said sheet with the image formed thereon; and a relaying section arranged in said space and configured to convey said sheets with images formed thereon to said sheet finishing section.
  • 8. An apparatus as claimed in claim 7, wherein said space includes, between said scanner section and said relaying section, a region adapted to allow a sheet jamming said relaying section to be removed.
  • 9. An apparatus as claimed in claim 7, wherein said relaying section conveys the sheets sequentially discharged by said sheet discharging section to said sheet finishing section.
  • 10. An apparatus as claimed in claim 7, further comprising a second sheet discharging section configured to discharge the sheets with the images formed thereon to an area between said scanner section and said relaying section.
  • 11. An apparatus as claimed in claim 10, wherein said second sheet discharging section is arranged in said relaying section.
  • 12. An apparatus as claimed in claim 10, further comprising a second sheet stacking section positioned on a top side of said relaying section and configured to stack the sheets sequentially discharged by said second sheet discharging section.
  • 13. An apparatus as claimed in claim 7, wherein said sheet finishing section and said relaying section are removable from said apparatus.
  • 14. An image forming apparatus comprising:discharge means, positioned on one end portion of a top of said apparatus, for allowing a sheet carrying an image thereon and discharged by usual sheet discharge to be stacked on the top of said apparatus via said discharge means; and relaying means extending horizontally on the top of said apparatus from said discharge means to another end portion which faces the one end portion, comprising transport means for transporting the sheet from said discharge means, and conveying means for conveying the sheet substantially horizontally in said transport means.
  • 15. An image forming apparatus comprising:scanning means for reading image information out of a document; image forming means for forming an image on a sheet and arranged below said scanning means thereby forming a space between said scanning means and said image forming means; sheet discharging means for discharging the sheet with the image formed thereon from a first end of said image forming means to said space; sheet stacking means, arranged in said space, for stacking sheets sequentially discharged from said sheet discharging means; sheet finishing means, adjacent to a second end of said image forming means, for finishing said sheet with the image formed thereon; and relaying means, arranged in said space, for conveying said sheets with images formed thereon to said sheet finishing means.
Priority Claims (6)
Number Date Country Kind
8-53333 Mar 1996 JP
8-61116 Mar 1996 JP
8-228381 Aug 1996 JP
8-313589 Nov 1996 JP
9-6761 Jan 1997 JP
9-13910 Jan 1997 JP
Parent Case Info

This application is a continuation of application Ser. No. 08/814,464, filed on Mar. 10, 1997, U.S. Pat. No. 6,112,047.

US Referenced Citations (8)
Number Name Date Kind
4385827 Naramore May 1983
4444491 Rinehart et al. Apr 1984
4582421 Hamlin et al. Apr 1986
4603971 Kukucka et al. Aug 1986
5017972 Daughton et al. May 1991
5331389 Fukuchi et al. Jul 1994
5422705 Omelchenko et al. Jun 1995
5918101 Kuroyanagi Jun 1999
Foreign Referenced Citations (1)
Number Date Country
61-145069 Jul 1986 JP
Continuations (1)
Number Date Country
Parent 08/814464 Mar 1997 US
Child 09/414447 US