Sheet discharge tray and a multiple bin sorter equipped with the same

Abstract

A sheet discharge tray for stacking discharged sheets has a detachable member detachably mounted to a main unit from which the sheets are discharged, and a fastening member, attached to the main unit, for fastening the detachable member to the main unit. By mounting the detachable member to the main unit, the tray is configured to link the detachable member and the fastening member, thereby increasing the structural rigidity of a multi-bin sorter. The sheet discharge tray ensures the rigidity of the apparatus, makes packaging work easier when shipping the product, has a compact structure, and is capable of protecting accessory parts such as a static electricity discharging member and sheet detecting members.

Description

BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT

The present invention relates to a sheet discharge tray and to a multi-bin sorter equipped with the same, and more particularly to a sheet discharge tray for stacking discharged sheets and a multi-bin sorter arranged with a plurality of sheet discharge trays in up and down directions.

Conventionally, sorters that sequentially sort sheets, having discharge trays or a plurality of bins for sequentially stacking by placing sheets formed with characters and/or images by an image forming apparatus such as a copier or printer thereupon, or a sheet discharge apparatus or sheet stacking apparatus, such as a mailbox that separates and stores user print jobs to each bin are well known in the art. Discharge trays in these apparatuses are detachably equipped at sheet discharge outlets (on the apparatus body). An example of such technology is disclosed in Japanese Patent Publication No. 2002-249273.

Various reasons for providing a detachable discharge tray can be raised. For example, when an apparatus is equipped with a plurality of discharge trays, and a high-capacity stacking function has priority over a discharge sheet sorting function that uses the plurality of trays, a lower discharge tray for stacking a high volume of sheets (see the aforementioned Japanese Patent Publication No. 2002-249273) can be employed by detaching one of the mid-positioned discharge trays. Another object of detachable discharge trays is to make it easier to package the product when shipping, even if there is only one discharge tray. Still further, detachably forming a discharge tray also makes it more convenient to remove discharged sheets if a problem occurs in discharge sheet conveyance. Detachable trays also make it easier to replace a damaged one or to perform other apparatus maintenance.

Also, Japanese Patent Publication No. 11-157722 discloses detachably equipping a stacking tray for stacking originals on an automatic document feeder apparatus installed on a copier. This is different from when sheets are output from the image forming apparatus described above.

Output sheets and/or originals become charged with static electricity when conveyed through and discharged from the apparatus. Thus, a static electricity discharging member is generally disposed near the discharge outlet of the apparatus to remove static electricity to improve discharging precision and alignment of sheets on a discharge tray. A mechanism is employed in the sheet discharge apparatus and/or the sheet stacking apparatus mentioned above to detect a full state which is the upper limit for stacking output and stacked sheets. Either an arm or a lever that touches a top surface of a sheet is used for such a detecting mechanism. Examples are disclosed in the Japanese Laid-open Patent Publications No. 2002-249273 and No. 8-259093.

However, when incorporating an accessory part, such as the static electricity discharging member, to the detachable discharge trays described above, special consideration must be taken to provide extra shock absorbing material when shipping the product. This translates into the disadvantages of a more complex packaging process and increased costs. Specifically, it is natural for special care to be taken when packaging the apparatus as a product to prevent it from being damaged when shipped, transported and installed. Generally, a minimum acceptable limit of shock absorbing material is prepared for the discharge trays. Because extra consideration must be paid to the accessory parts, such as the static electricity discharging member, packaging work becomes more complex, and again, that translates into cost increases.

It is also necessary to consider grounding, in other words continuity of the static electricity discharging member. If a static electricity discharging member is arranged on a detachable discharge tray, it is necessary for the discharge tray to have a structure for continuity, in addition to the problems outlined above. This also adds to the increase in cost.

Furthermore, when a detecting mechanism uses an arm or a lever member as for detection described above, the arm and/or lever projects outward from the apparatus. Therefore, if a discharge tray is removed, there is the potential for a user to carelessly touch these parts which could cause a decrease in detecting accuracy. There is also the problem of such projection inviting damage to itself.

Furthermore, a configuration that incorporates a portion of a discharge tray inside the apparatus, for example providing a detachable discharge tray structure that disengages hooks formed on both edges of the discharge tray from engaging orifices formed in both inner side walls of the apparatus body, has the problem of not being able to increase the rigidity of the apparatus itself.

An object of the present invention, therefore, is to provide a sheet discharge tray that ensures the rigidity of the apparatus, makes packaging work easier when shipping the product, has a compact structure, and is capable of protecting the accessory parts, such as a static electricity discharging member and sheet detecting members.

Another object of the present invention is to provide a multi-bin sorter that ensures the rigidity of the apparatus side, that makes packaging work easier when shipping the product, and reduces distribution (packaging) costs, that has a compact structure and is capable of protecting accessory parts, such as a static electricity discharging member and sheet detecting members.

Further objects and advantages of the invention will be apparent from the following description of the invention.

SUMMARY OF THE INVENTION

To attain the aforementioned objects, a first aspect of the present invention is a discharge tray composed of a detachable member detachably mounted to a main unit and a fastening member fastened to the main unit, for a sheet discharge tray for stacking discharged sheets.

According to the first aspect of the present invention, a tray is separated into a detachable member detachably mounted to the main unit, and a fastening member fastened to the main unit. By mounting or installing the detachable member to the main unit, the tray is configured to link the fastening member and the detachable member. For that reason, because the fastening member that composes the tray is fastened to the main unit, the rigidity of the main unit side is increased, even if the tray is a detachable structure. Also, the fastening member can be packaged as one body with the main unit, and the detachable member, which is comparatively smaller in size than the overall tray itself, can be packaged separately. This makes packaging work easier when shipping the product, and decreases the costs associated with product distribution (packaging). Still further, in the event that a problem should occur in sheet discharge conveyance while operating the main unit, the detachable member can be removed from the main unit to enable a user to access the inside of the main unit. This makes the work to remedy problems more efficient.

Also according to the first aspect of the present invention, static electricity discharging members are disposed on the bottom surface of the fastening member to remove static electricity that tends to be charged to discharging sheets. This allows the fastening member fastened to the main unit to protect the static electricity discharging members when transporting or shipping the product, and eliminates the need for grounding work after product delivery.

By equipping the fastening member above a movable lever member of a lever sensor composed of a movable lever member that touches a top surface of discharged sheets, and a sensor member for detecting a stacking amount of discharged sheets through the rotation of the movable lever member, it is possible for this fastening member to protect the movable lever member. Therefore, this configuration prevents reduced detecting accuracy caused by damage during shipment or by carelessly touching the part while a user is operating the main unit.

Also, if the fastening member is disposed above a weight member that pushes discharging sheets downward paired with the movable lever member in a width direction of discharging sheets, the fastening member can also protect the weight member in the same way as the movable lever member. Therefore, this also prevents product damage that can occur at shipping and prevents negative effects on product functions which can be caused by careless user contact when handling the machine. Furthermore, if the fastening member has a plurality of ribs on its bottom surface to guide discharging sheets, sheet alignment will be improved and the rigidity of the fastening member will also be ensured. If the detachable member has a plurality of ribs that connect to the plurality of ribs of the fastening member, the rigidity of the detachable member will be also increased, as well as the strength of the entire tray.

In order to attain the aforementioned objects, a second aspect of the present invention is the aforementioned tray composed by connecting the detachable member detachably mounted to the main unit, and the fastening member fastened to the main unit, in a multi-bin sorter arranging a plurality of sheet discharge trays in up and down directions for stacking sheets discharged from sheet discharge outlets.

The second aspect attains the same effects as the first aspect of the present invention. Sheet discharge trays of the first aspect are arranged in plurality in up and down directions to have the notable effects of facilitating packaging work when shipping the product and reducing the costs associated with product distribution (packaging).

According to the second aspect of the present invention, it is preferred that the fastening member be configured as one body with an upright surface of the main unit formed with sheet discharge outlets, in order to ensure rigidity and to make the system more compact. Also, the fastening member has static electricity discharging members on its bottom surface for eliminating static electricity charged to discharging sheets, and is integrally composed with the upright surface of the main unit formed with sheet discharge outlets. It is preferred that the fastening member has a projecting shape to protect members positioned below, from above.

Furthermore, if the system is configured to include a movable lever, equipped near a sheet discharge outlet, that rotates to touch a top surface of sheets stacked on a tray, a sensor for detecting the stacking state of sheets stacked on the tray along with the rotation of the movable lever, and first preventing means in a direction opposite to the direction of sheet conveyance for preventing sheets from being inserted to above the movable lever, the first preventing means prevents sheets from being inserted to above the movable lever even if a user carelessly inserts sheets into the tray from a direction opposite to the direction of sheet conveyance. Thus, sheets are unable to be above the movable lever, so the benefit is that mis-operations caused when sheets are discharged to the tray from the sheet discharge outlet will not occur, the sheet stacking state is accurately detected, and any discharge problems of sheets discharged from the sheet discharge outlet will not occur.

The first preventing means have rotatable plate-shaped members. The plate-shaped members rotate freely within a predetermined angle in a first rotating direction by being touched by sheets being discharged from the sheet discharge outlet. In a second direction opposite to the first direction, where sheets touch plate-shaped members in a direction opposite to the direction of sheet discharge, it is acceptable to configure the members so that their tolerable rotating angle of the second direction is controlled to be smaller than the tolerable rotating angle of the first angle. In this case, first preventing means have plate-shaped members whose rotating ranges are controlled at predetermined angles, and supporting members that pivotally support the plate-shaped members. Projections formed on ends of a rotating shaft of the plate-shaped members contact with a portion of the inner wall of the support member bearing to control the range of rotation of the plate-shaped members. Trays are obliquely arranged. The bottom ends of the plate-shaped members are preferred to be positioned above the sheet maximum stacking amount detection position where the movable lever is positioned when the maximum number of sheets is detected by the sensor, using the planar surface of the tray as a reference.

Furthermore, it is preferred that the plate-shaped members hang downward substantially vertically under their own weight. In this state, in the event that a user manually inserts sheets in a direction opposite to the direction of sheet discharge, the ends of the inserted sheets contact the plate-shaped members causing them to rotate from their substantially vertical hanging posture to the predetermined angle in the second direction where the rotation is controlled. This makes it possible to guide the ends of the inserted sheets toward the tray. It is also acceptable for the projections equipped at one end of the support members to be positioned at predetermined positions inserted in concave portions formed in the main unit wall surface for the first preventing means.

It is also acceptable to equip rotatable weight members near a sheet discharge outlet for pushing sheets discharged from the sheet discharge outlet downward, and second preventing means in a space above a tray downstream in the direction of sheet transport of the weight members, for preventing the insertion of sheets to above the weight members, in a direction opposite to the direction of sheet discharge. The movable lever members and weight members have substantially the same shape, and it is acceptable to equip them in pairs in a direction that intersects the direction of sheet discharge. It is also acceptable for first preventing means and second preventing means to have substantially the same shape.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an external, perspective view of a multi-bin sorter that can apply the present invention, installed in an image forming apparatus.

FIG. 2 is a perspective view of a portion of the multi-bin sorter according to the present invention with a detachable member linked to a fastening member installed in a main unit.

FIG. 3 is a perspective view of an area near a sheet discharge outlet of the multi-bin sorter.

FIG. 4 is a fragmentary perspective view from below the multi-bin sorter.

FIG. 5 is a perspective view of the multi-bin sorter as seen from above with trays removed, and first and second preventing means installed.

FIG. 6 is a perspective view of the multi-bin sorter as seen from above with trays mounted, and the first and the second preventing means installed.

FIGS. 7A, 7B, and 7C are perspective views of the first preventing and the second preventing means of the multi-bin sorter, wherein FIG. 7A shows a plate-shaped member hanging downward under its own weight in a substantially vertical posture; FIG. 7B shows the plate-shaped member rotated in a sheet discharge direction; and FIG. 7C shows the plate-shaped member rotated in a direction opposite to the sheet discharge direction and stopped.

FIGS. 8A, 8B, and 8C are side views of the first preventing means and the second preventing means, wherein FIG. 8A shows the state of FIG. 7A; FIG. 8B shows the state of FIG. 7B; and FIG. 8C shows the state of FIG. 7C.

FIG. 9 is a fragmentary sectional view of the positional relationships between a movable lever and the plate-shaped member.

FIG. 10 is a fragmentary perspective view of the first preventing means being installed to the multi-bin sorter.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the multi-bin sorter according to the present invention are described below with reference to the accompanying drawings.

As shown in FIG. 1, the multi-bin sorter 10 of the present invention is mounted to a side of an image forming apparatus having faxing, copying, scanning and/or printer functions as the main unit.

The image forming apparatus 1 has an automatic document feeder unit (commonly known as an ADF) 2 for automatically conveying originals, on the top portion of the apparatus. An image reading unit, not shown, for reading originals is arranged below the automatic document feeder 2. For that reason, the image reading unit can read originals using either of two methods. Specifically, this unit can read characters and images formed on an original while the original is conveyed by the automatic document feeder 2, or it can read characters and images formed on the original placed in a stationary position on a platen, not shown. The cover, such as a pressure plate 3, over the platen can be opened in an upward direction to allow the original to be placed stationary on the platen.

A display unit 4 for displaying processes of the image forming apparatus 1, and a UI panel 7 for issuing operating instructions to the image forming apparatus 1 are arranged on the front side (the near side of FIG. 1) of the image forming apparatus 1. A lock lever 5 that opens the inside of the image forming apparatus 1 is arranged on the top portion of a multi-bin sorter 10 of a top cover 6. The lock lever 5 is configured to be released when there has been a conveyance problem of a sheet formed with an image, to solve the problem (by removing a so-called paper jam) by rotating the upper cover along with the automatic document feeder 2, the pressure plate 3, the display unit 4, the UI unit 7, and the image reading unit mentioned above upward and away from the multi-bin sorter 10, thereby exposing the inside of the apparatus, not shown.

The image forming apparatus 1 has an interface that connects to a PC via a printer cable or network cable, not shown. This image forming apparatus 1 is used as a multi-functional device having a printing function for printing characters and images generated on the PC, a faxing function for sending and receiving character and image data read by an image reading unit connected to a telephone/communication line, and copying and scanning functions that can be used independent of a PC.

Discharge trays 11a, 11b, and 11c are equipped along up and down directions for stacking discharged sheets, on one side of the multi-bin sorter 10. Each of the discharge trays 11a, 11b, and 11c is installed at a slant having a predetermined angle.

It is possible to operate the UI 7 to select either the discharge tray 11a, 11b, or 11c as the destination tray (for stacking) of sheets discharged from the image forming apparatus 1, depending on the way the image forming apparatus 1 is used. For example, if sheets are printed, they can be stacked on the discharge tray 11a. The discharge tray 11b can be used for facsimiles, and the discharge tray 11c can be used for copies. In addition, these discharge trays can be used as mail bin sorters (in a mailbox system) by sorting sheets differentiating each discharge tray to use for each user by selecting the discharge tray that corresponds to the user's needs. Of course, if the desired discharge tray is full of stacked sheets, the user can switch subsequent sheets to be discharged and stacked in a different discharge tray.

As shown in FIG. 2, each of the discharge trays 11a, 11b and 11c is composed of a detachable member 42 detachably mounted to the main unit 41 of the multi-bin sorter 10 and a fastening member 43 fastened to the main unit 41. The fastening member 43 is formed as one body with the upright surface 48 of the main unit 41 formed with sheet discharge outlets 12 (12a, 12b, and 12c), extending to both sides of the multi-bin sorter 10, and projecting outward from the image forming apparatus 1. The discharge trays 11a, 11b, and 11c share the same structure. Therefore, an explanation will focus on the connecting structure of the uppermost discharge tray 11a. Explanations on the discharge tray 11b and 11c shall be omitted. Note that the upper and side portion coverings of the multi-bin sorter 10 have been omitted from the image of FIG. 2 to facilitate understanding of the internal configuration of the multi-bin sorter 10.

Cylindrical hooks 46 projecting outward to the outer sides (the main unit 41 side) are formed at the upper corners of both side edges. Engaging holes 45 are formed in both side inner walls 44 on the main unit 41 to engage these hooks 46. By inserting the hooks 46 of the detachable member 42 to engage the engaging holes formed in the main unit 41, the separated detachable member 42 and fastening member 43 become connected, thereby configuring the discharge tray 11a. At this time, the tray trailing edge support portion 47, at substantially the center of the detachable member 42, having a predetermined width positioned at the leading edge in the direction of insertion shown in FIG. 2, is positioned to touch the bottom surface of the opposing fastening member 43.

To detach the detachable member 42 from the main unit 41 and separate it from the fastening member 43, one lifts the end opposite to the tray trailing edge support member 47 of the detachable member 42 to free the tray trailing edge support member 47 from its contact with the bottom surface of the fastening member 43. Then, by pulling the detachable member 42 out and upward at an angle, the hooks 46 of the detachable member 42 can easily be detached from the engaging holes 45 formed in the main unit 41.

Sheet discharge outlets 12 (12a, 12b, and 12c) are formed in the upright surface 48 of the main unit 41 for discharging sheets from the image forming apparatus 1 to the discharge trays 11 (11a, 11b, and 11c). Sheets discharged from the sheet discharge outlets 12a, 12b, and 12c are stacked on each of the discharge trays 11a, 11b, and 11c. Note that according to this embodiment of the present invention, the maximum stacking amount for the uppermost discharge tray 11a, when using A4 size sheets having a basic weight of 80 g/m² is approximately 100 sheets. For the second and third level discharge trays 11b, and 11c, the maximum stacking amounts are approximately 50 sheets, when using A4 size sheets having basic weights of 80 g/m².

As a rule, the sheet discharge outlets 12a, 12b, and 12c, and other members arranged in close proximity thereto share the same configuration. However, a movable lever member 14a and a weight member 15a, described in detail below, arranged in close proximity to the sheet discharge outlet 12a are wider extending in the center direction (the direction intersecting the sheet discharge direction) of the sheet discharge outlet 12a than the movable lever members 14b and 14c and the weight members 15b and 15c arranged in close proximity to the sheet discharge outlets 12b and 12c. Their shapes are different. The reason for this is to support special sheets that have a narrow width, such as envelopes or post cards discharged based on the center of the discharge outlet. For this reason, the following will explain members near the sheet discharge outlets 12b. An explanation of the sheet discharge outlets 12a, and 12c will be omitted.

As shown in FIG. 3, a freely moving, movable lever member 14b that functions in combination with a photo-interrupter 27, described below, is disposed near the sheet discharge outlet 12b as a detecting lever that touches the uppermost surface of a sheet discharged to the discharge tray 11b. The leading end of the movable lever member 14b has a bent shape. The movable lever member 14b is arranged in a position that intersects the sheet discharge direction. Specifically, it is positioned to be able to touch the portion near a corner of a sheet stacked on the discharge tray 11b, in the width direction of a discharged sheet. As the number of sheets stacked on the discharge tray 11b increases, and reaches a predetermined number, the movable lever member 14b touches the top surface of the uppermost stacked sheet. When the predetermined sheet volume increases further, the movable lever member 14b rotates to a position to detect the maximum sheet stacking capacity (volume of sheets).

The weight member 15b that pushes sheets discharged from the sheet discharge outlets 12b downward by touching their top surfaces, is disposed as a pair to the movable lever member 14b on the opposite side (on the opposite side of the position of the movable lever member 14b in a direction intersecting the sheet discharge direction) thereof (the movable lever member and the weight member are a pair for the same sheet discharge outlet), sandwiching the sheet discharge outlet 12b. The weight member 15b is also rotatably disposed, like the movable lever member 14b. Note that in this embodiment, the movable lever members 14b and 14c, and the weight members 15b and 15c share the same configuration.

In the same way as the movable lever member 14b, the weight member 15b touches the top surface of the uppermost stacked sheet when the number of sheets stacked on the discharge tray 11b increases to reach a predetermined volume. The weight member 15b also employs a freely rotating configuration so it continues rotating motion simultaneously to the rotating motion of the movable lever member 14b. The sheet pressing function of the weight member 15b improves the alignment of sheets stacked in the discharge tray. Note that in the same way as the weight member 15b, the movable lever member 14b also has a function for pushing sheets being discharged in a downward direction.

Discharge rollers 51 rotatingly driven by a power source and a drive transmission mechanism, not shown, are disposed at both sides of the sheet width direction on a shaft 22 at the sheet discharge outlets 12b. Discharge rollers 52 are opposingly arranged under each of the discharge rollers 51 to sandwich and discharge sheets. Note that by arranging the discharge rollers 52 in a sheet discharge direction side in the horizontal direction with regard to the discharge rollers 51, discharged sheets are discharged moving upward.

The movable lever member 14b is fixed to the shaft 24. The shaft 24 rotates freely as a rotating shaft. An arm 26 integrally formed with a douser plate 25 is fixed to the other end of the shaft 24. The movable lever member 14b, the arm 26 and the douser plate 25 integrally rotate. Also, along with the rotating motion of the movable lever member 14b (as well as for the douser plate 25 and the arm 26), the douser plate 25 advances into and interrupts the light path of a photo-interrupter 27 equipped with light emitting and receiving elements that detects the stacked state of sheets stacked on the discharge tray 11b.

To describe this element in more detail, according to this embodiment of the present invention, a slit 25a is formed in the douser plate 25. Each time a sheet is discharged, the sheet raises the movable lever member 14b (as well as the weight member 15b). This causes the douser plate 25 to rotate and rise in synchronization as it advances into the light path of the photo-interrupter 27. The part travels from its initial, transmissive state (a), to an interrupting state (b) (the douser plate higher than the slit 25a interrupts the photo-interrupter 27), a transmissive state (c) (the photo-interrupter 27 is passing through the slit 25a), and an interrupting state (d) (the douser plate 25 is lower than the slit 25a interrupting the photo-interrupter). During sheet discharge, the interrupted state of (d) is continued, but when sheet discharge is completed, the movable lever member 14b (as well as the weight member 15b) is freed from pressing sheets and falls, thereby rotating the douser plate 25 downward. The slit 25a of the douser plate 25 moves from the interrupting state (d) to the transmissive state (c) to the interrupting state (b), and to the transmissive state (a) again, to return to its original status. Note that when the volume of sheets stacked on the discharge tray 11b has reached a full state, in other words, the maximum amount that the tray can stack, the return motion (the motion of rotating downward) of the douser plate 25 stops at the interrupting state (b). A control mechanism, not shown, determines that the tray has reached its full, or maximum stacking amount.

As shown in FIG. 3, the weight member 15b is fixed to the shaft 28. The shaft 28 rotates freely as a rotating shaft. Note that a gear 29 is disposed on one end of the drive shaft 22 as the rotating shaft of the discharge rollers 51. Drive from another gear, not shown, meshes with the gear 29 from above to transmit drive and rotatingly drive the shaft 22. Therefore, the shaft 22 and shaft 28 are connected.

As shown in FIG. 2, the fastening member 43 is disposed at a position to protect the movable lever member 14b and weight member 15b. In other words, the fastening member 43 that configures a part of the discharge tray 11a protects the movable lever member 14b and weight member 15b. The fastening member 43 that configures a part of the discharge tray 11b protects the movable lever member 14c and weight member 15c. (See FIG. 4.) According to this embodiment of the present invention, the gap between the discharge trays 11 is narrow at less than 40 mm. Because the discharge trays 11 are disposed at an angle, it is difficult to look inside. This has been considered from a technical standpoint. Note that because there is no other discharge tray above the discharge tray 11a, it is easier to view inside there. Therefore, a simple plate-shaped member projecting from the upright surface of the main unit 41 protects the movable lever member 14a and weight member 15a.

Note that according to this embodiment of the present invention, each of the detachable members 42 and fastening members 43 that configure the discharge trays 11 (11a, 11b, and 11c) has convex and concave portions. The convex portion of the fastening members 43 is equipped projecting from the sheet discharge outlets 12 to protect the movable lever member 14b and weight member 15b equipped therebelow, from above. When the detachable member 42 is installed to the main unit 41, each part (namely the detachable member 42 and the fastening member 43) has a configuration for connecting. Specifically, the concave portion of the detachable member 42 engages the convex portion of the fastening member 43, and the convex portion of the detachable member 42 engages the concave portion of the fastening member 43. However, it is also perfectly acceptable to configure the discharge trays 11 to connect the detachable member 42 and the fastening member 43 by forming them to be flat, and not have these concave and convex portions.

As can be seen in FIGS. 2 and 3, static electricity discharge brushes 13 (13C is shown in FIG. 3) are equipped at the bottom (the under surface) of the fastening member 43 as static electricity discharging members for removing static electricity charged to sheets, by touching the sheet being discharged from the sheet discharge outlets 12. In other words, the bottom (the under surface) of the fastening member 43 composes a static electricity discharge brush (static electricity discharging member) mounting portion. As is clear from the drawings, the static electricity discharge brushes 13b are mounted to the bottom of the fastening member 43 that configures the discharge tray 11a. The static electricity discharge brushes 13c are mounted to the bottom of the discharge tray 11b. (Also see FIG. 3.) Note that FIG. 3 schematically shows the static electricity discharge brushes 13c.

As shown in FIG. 2, a plurality of ribs 49 are formed on the top surfaces of the detachable member 42 and the fastening member 43 that compose the discharge trays 11 (11a, 11b, and 11c) to improve the alignment of sheets discharged to and stacked on the trays. Some of these are disposed so that they are connected (continuous) having a slight gap when the detachable member 42 is mounted to the main unit 41. (Also see the discharge tray 11b of FIG. 4.) FIG. 4 shows the bottom surface of the discharge tray 11b that is positioned in the middle, and the configuration near the sheet discharge outlet 12c that discharges sheets to the bottommost positioned discharge tray 11c. According to this embodiment of the present invention, three discharge trays (three bins) 11a, 11b, and 11c are provided. The top surfaces of sheets discharged from the sheet discharge outlet 12c that discharges sheets to the lowest-positioned discharge tray 11c via the discharge roller 52 opposingly positioned to the discharge roller 51 rotatingly driven by drive force from a drive mechanism, not shown, touch the plurality of ribs 54 on the bottom surface of the detachable member 42 of the discharge tray 11b positioned thereabove. While being discharged from the sheet discharge outlets 12c the sheets are removed of static electricity by the static electricity discharge brushes 13.

However, if a sheet has a pronounced upward curl, the sheet pushes the static electricity discharge brushes 13c upward while being conveyed forward in contact with the static electricity discharge brushes 13c to the plurality of ribs 53 equipped on the bottom surface of the fastening member 43 of the discharge tray 11b. In this way, the plurality of ribs 53 equipped on the bottom surface of the fastening member 43 function to guide a discharging sheet while indirectly (interposed by the static electricity discharge brushes 13) supporting the sheet, when discharging a sheet having a pronounced upward curl. Then, while the top surface of the sheet touches the plurality of ribs 54 and 55 equipped on the bottom surface of the detachable member 42 of the discharge tray 11b, the sheet falls and is collected on the lower discharge tray 11c, being guided by the ribs 54 and 55.

In this way, the ribs 53 (disposed on the bottom surface of the fastening member 43), and the ribs 54 and 55 (both disposed on the bottom surface of the detachable member 42) hold the posture of the discharging sheet properly and have a utility in guiding discharging sheets to the discharge tray 11c. Also, as is clear in the drawings, portions of the ribs 53 on the fastening member 43 side and the ribs 54 on the detachable member 42 side are disposed to connect with a slight gap when the detachable member 42 is installed to the main unit 41 and connected to the fastening member 43.

Note that a fastening member 56 shown in FIG. 4 as a portion of the discharge tray 11c positioned at the lowermost position is configured as a bottom portion of the multi-bin sorter 10 and is shaped for stability when the tray is installed on the apparatus.

Furthermore, on the multi-bin sorter 10, as shown in FIGS. 5 and 6, first preventing means 16a and 16b are equipped for preventing sheets (bundles) from advancing (being inserted) to above the movable lever members 14b and 14c and allowing careless human contact with the movable lever members 14b and 14c. Even if a user inadvertently, manually inserts sheets (or a sheet bundle) into the discharge trays 11b and 11c in a direction opposite to the sheet discharging direction, the first preventing means 16a and 16b are established at a downstream side in the direction of sheet discharge of the movable lever members 14b and 14c, so they protect these movable lever members. According to this embodiment of the present invention, the gap between the discharge trays is narrow at less than 40 mm and the trays are long, so it is difficult to look inside. This has been considered from a technical standpoint. Note that the uppermost positioned discharge tray 11a can stack twice the amount of sheets of the other trays 11b and 11c. Also, there is no other tray above the discharge tray 11a, so it is easy to view inside, so there are no first preventing means established for the movable lever member 14a.

Second preventing means 17a and 17b are equipped in a space above the discharge trays 11b and 11c, for preventing sheets (bundles) from advancing (being inserted) to above the weight members 15b and 15c and allowing careless human contact with the weight members 15b and 15c. Again, even if a user inadvertently, manually inserts sheets to the discharge trays 11b and 11c from a direction opposite to the sheet discharging direction, in the same way as the first preventing means 16a and 16b, the second preventing means 17a and 17b are established at a downstream side in the direction of sheet discharge of the weight members 15b and 15c and protect the weight members 15b and 15c. The second preventing means 17a and 17b share the same configuration and the same shape as the first preventing means 16a and 16b. The relationships of the movable lever member 14b and weight member 15b are the same. The first preventing means 16 and the second preventing means 17 are disposed at the same discharge outlets in pairs (first preventing means 16a is paired with the second preventing means 17a, and the first preventing means 16b is paired with the second preventing means 17b) in the width direction of discharging sheets. Furthermore, according to this embodiment of the present invention, the first preventing means 16a and 16b, and the second preventing means 17a and 17b all share the same configuration. Note that the uppermost positioned tray la is not equipped with second preventing means for the weight member 15a. Additionally, FIG. 3 that shows the configuration of the multi-bin sorter 10 near the sheet discharge outlet 12b does not show the first preventing means 16a and 16b, and the second preventing means 17a and 17b. (Neither does FIG. 4.) As shown in FIGS. 7A to 7C, and in FIGS. 8A to 8C, the first preventing means 16a and 16b (as well as the second preventing means 17a and 17b) have plate-shaped members 32 comprising a rotating shaft 31 and a hollow support member 33 that pivotally supports the rotating shaft 31. A projection 34, substantially fan-shaped in cross-section, is formed on one end of the rotating shaft 31. A convex control portion 35 is equipped on a portion of a bearing inner wall of the support member 33 to control the range of the rotation of the projection 34. Also, a projection 36 is disposed on one end of the support member 33. This projection 36 is inserted into the main unit, as described below (see FIG. 10), to position the first preventing means 16 (particularly the plate-shaped member 32) at a predetermined position in the space above the tray 11, downstream of the sheet discharge direction of the movable lever member 14b.

With the configuration described above, the plate-shaped member 32 can freely rotate within a predetermined angle around the rotating shaft 31 pivotally supported by the support member 33. However, when the plate-shaped member 32 exceeds the predetermined angle, the projection 34 of the plate-shaped member 32 side touches the control portion 35 of the support member 33 side to control and stop the rotating action.

FIGS. 7A to 7C and FIG. 8A to 8C each show the same status. FIGS. 7A and 8A show the first preventing means 16 (projection 36) at the initial state inserted into the machine side of the apparatus and the plate-shaped member 32 hanging downward substantially vertically by its own weight.

FIGS. 7B and 8B show the plate-shaped member 32 being lifted by a discharging sheet in the direction of an arrow F (a first direction). These show the plate-shaped member 32 rotating from the state shown in FIGS. 7A and 8A. This rotated state continues while sheets are being discharged. Note that when the trailing edge of a discharging sheet is completely discharged from the sheet discharge outlet, the plate-shaped member 32 is freed from its contact with the sheet and allowed to return to the state shown in FIGS. 7A and 8A, by rotating in the opposite direction of the first direction under its own weight.

FIGS. 7C and 8C show the projection 34 of the plate-shaped member 32 touching the control portion 35 of the support member 33. This action effectively controls and stops the rotation of the plate-shaped member 32. Specifically, this action occurs if the leading ends of sheets or a sheet bundle touches the plate-shaped member 32 when a user removes sheets or a sheet bundle from the top of the tray, and returns the sheets or sheet bundle back to the tray. If sheets or a sheet bundle is manually reinserted in a direction of arrow R, a reverse direction of the sheet discharge direction (a second direction) from the sheet discharge outlet (the direction of arrow F in FIGS. 7B and 8B), the plate-shaped member 32 rotates from a substantially vertical hanging posture, shown in FIGS. 7A and 8A, and rotates in an opposite direction of the rotating direction of the plate-shaped member 32 shown in FIGS. 7B and 8B. In this state, the plate-shaped member 32 is positioned obliquely. This guides the leading ends of sheets or a sheet bundle being returned to the tray, toward the tray positioned below. Also, when the contact of the leading ends of the sheets or sheet bundle being returned to the tray is released from the plate-shaped member 32, the plate-shaped member 32 rotates in the opposite direction under its own weight to return to the states shown in FIGS. 7A and 8A.

According to this embodiment of the present invention, the plate-shaped member 32 is configured to be able to freely rotate within an angle of 130°. As shown in FIGS. 7A and 8A, the plate-shaped member 32 uses the hanging state as a reference (0°). As shown in FIGS. 7C and 8C, the rotating angle for the plate-shaped member 32 to rotate in the direction of the arrow R (a second direction), is set by the relationship of the projection 34 and control portion 35 so that it is smaller than the rotating angle allowed for the plate-shaped member 32 to rotate in the direction of the arrow F (the first direction) in the direction of sheet discharge, shown in FIGS. 7B and 8B.

As described above, sheets discharged from the sheet discharge outlet 12 by the discharge rollers 21 (also the discharge roller 51) and discharge roller 23 (also the discharge roller 52) are stacked sequentially on the discharge tray 11. (Stacked sheets are omitted from the drawings.) FIG. 9 shows the movable lever member 14 using a sensor, not shown, (the photo-interrupter 27 in FIG. 3) that touches the top surface of the uppermost sheets of sheets stacked on the tray 11 to detect a full state which is the maximum stacking capacity of the tray. In this state, the bottom end of the plate-shaped member 32 of the first preventing means 16 is disposed to be positioned higher than the sheet maximum stacking amount detection position (the position depicted in FIG. 9) where the movable lever member 14 is positioned, using the plane of the obliquely disposed tray 11 as a reference.

Specifically, the bottom end position of the plate-shaped member 32 of the first preventing means 16 is positioned slightly above the lowest point position of the movable lever member 14 that touches the top surface of the uppermost sheet. To make this easier to understand, FIG. 9 includes dotted lines that delineate the lowest point position of the movable lever member 14 that touches the top surface of the uppermost sheet and the bottom end position of the plate-shaped member 32 of the first preventing means 16 in parallel with the plane of the tray 11. Note that the mounting height positions of the second preventing means 17 are the same as the first preventing means 16.

As shown in FIG. 10, the projection 36 established on an end of the support member 33 of the first preventing means 16 mates with the system by being inserted into a concave portion 39 formed in a portion of the apparatus wall surface 38, above the sheet discharge outlet 12 thereby positioning the first preventing means 16. This configuration positions the first preventing means 16 (particularly, the plate-shaped member 32) at a predetermined position in a space above the tray 11, downstream in the direction of sheet discharge of the movable lever member 14. Note that the mounting configuration of the second preventing means 17 to the main unit is exactly the same.

The following will explain the action of the multi-bin sorter 10 according to this embodiment of the present invention.

The discharge trays 11 (11a, 11b, and 11c) of the multi-bin sorter 10 of this embodiment of the present invention are separated into the detachable member 42 that is detachably mounted to a main unit 41, and the fastening member 43 fastened to an upright surface 48 of the main unit 41. By installing the detachable member 42 to the main unit 41, the fastening member 43 and the detachable member 42 are connected, thereby configuring a tray. For that reason, because the fastening member 43 that configures the discharge tray 11 is fastened to the apparatus body, the rigidity of the multi-bin sorter 10 is increased even if the discharge tray 11 is detachably configured. A portion of the discharge trays 11 is positioned inside the main unit, in other words, this increases the rigidity of the device that has the projecting portion. Also, the fastening member 43 can be packaged with the multi-bin sorter 10 and the detachable member 42 which is comparatively smaller than the discharge trays 11 can be packaged separately, so packaging work when shipping the multi-bin sorter 10 product is simpler, and the costs associated with distribution (packaging) are reduced. Furthermore, when performing maintenance, for a problem, such as when a sheet discharge jam occurs during operation of the multi-bin sorter 10, the multi-bin sorter 10 can be accessed by removing the detachable member 42 from the main unit 41, so the work to solve such problems is more efficient.

With the multi-bin sorter 10 of this embodiment of the present invention, static electricity discharge brushes 13 are disposed on the bottom (under side) of the fastening member 43, so the static electricity discharge brushes 13 are protected by the fastening member 43 fastened to the main unit 41 when shipping the multi-bin sorter 10, and there is no need to ground the device after product delivery.

Still further, with the multi-bin sorter 10 according to this embodiment of the present invention, because a fastening member 43 is equipped above the movable lever member 14 of the lever sensor composed of the movable lever member 14 that touches the top surface of discharging sheets, and the sensor members of the shaft 24, the douser plate 25, the arm 26 and the photo-interrupter 27 that detect the stacking amount of sheets with the rotation of this movable lever member 14, the movable lever member 14 is protected by the fastening member 43. Therefore, this prevents damage when the product is shipped, and it prevents degraded detection accuracy cause by carelessly coming into contact with something when the machine is used. Also, because a fastening member 43 is disposed above the weight members 15 that push discharging sheets downward, equipped to be a pair with the movable lever member 14b in the width direction of discharging sheets, the fastening member 43 also protects the weight member 15 in the same way as the movable lever member 14. Therefore, this also prevents damage when shipping the product and prevents reduced function cause by careless contact when using the machine.

With the multi-bin sorter 10 of this embodiment of the present invention, the fastening member 43 has on its bottom surface a plurality of ribs 53 that guide discharging sheets, as described above. This feature increases sheet alignment and ensures the rigidity of the fastening member 43. The detachable member 42 has a plurality of ribs 54 and 55 that link with the plurality of ribs 53 of the fastening member 43 when mounted to the main unit 41. Therefore, discharging sheets maintain a good posture, and this configuration enhances the rigidity of the detachable member 42, and strengthens the overall discharge trays 11.

Also, with the multi-bin sorter 10 of this embodiment of the present invention, the top surface of discharged sheets from a sheet discharge outlet 12 touches the movable lever member 14. This rotates the movable lever member 14, and along with that rotation, the detecting mechanism composed of the shaft 24, the arm 26, the douser plate 25, and the photo-interrupter 27 detect the state of stacked sheets. In other words, the detecting mechanism detects the stacking status of single sheets discharged from a sheet discharge outlet 12. Also, a control mechanism, not shown, determines the full status, which is the maximum stacking amount of sheets, when the return operation of the douser plate 25 is stopped at the light interrupting state of (b), as described above. Therefore, the multi-bin sorter 10 has a detecting mechanism for detecting one sheet at a time stacked on the discharge tray 11 from a sheet discharge outlet. This accurately detects the stacking state of sheets on the discharge tray 11, and a full state of the discharge tray.

The multi-bin sorter 10 of this embodiment of the present invention has first preventing means 16a and 16b equipped at a downstream side in the direction of sheet discharge of the movable lever members 14b and 14c, and in the space above the trays 11b and 11c. The first preventing means 16a and 16b prevent sheets (a bundle) from becoming inserted to above the movable lever members 14b and 14c, even when a user removes sheets (a bundle) once and returns them back to top of the trays 11b and 11c in the reverse direction of sheet discharge. With conventional multi-bin sorters, if sheets (or a bundle) whose edges are curled are re-inserted into the tray, the curled end of the sheets will be caught in the upper side of the detection lever for detecting the stacking amount of sheets stacked on the tray and cause mis-detections when detecting the sheet stacking amount. Thereafter, sheet discharge problems can occur, and if the sheets are forcefully returned, there is the possibility of damaging the detection lever. To solve those issues, the multi-bin sorter 10 uses the first preventing means 16a and 16b prevent sheets from entering above the movable lever members 14a and 14b, even if sheets are carelessly re-inserted into a tray from a direction that is opposite to the direction of sheet discharge, so there are no mis-operations when discharging sheets from the sheet discharge outlets 12b, and 12c to the trays 11b and 11c. Also, the status of the stacking of sheets can be precisely detected, so there are no discharge problems in sheets discharged from the sheet discharge outlets 12b, and 12c. The plate-shaped member 32 blocks (or protects) sheets (or a bundle) so the movable lever member 14b is not damaged. Similarly, the second preventing means 17 (17a and 17b) prevent damage of the weight member 15 (15a and 15b).

Furthermore, with the multi-bin sorter 10 of the present invention, first preventing means 16 and second preventing means 17 are equipped in pairs. Even if sheets (or a bundle) are inserted in the direction opposite to the sheet discharge direction, the projection 34 on the plate-shaped member 32 touches the control portion 35 on the support member 33 thereby controlling the rotating movement. Because of the oblique position (see FIGS. 7C and 8C), the leading ends of sheets (or sheet bundle) re-inserted to the trays 11b or 11c are guided properly toward the trays 11b and 11c.

With the multi-bin sorter 10, the bottom end of the plate-shaped member 32 of the first preventing means 16 is disposed to be positioned above the sheet maximum stacking amount detection position (see FIG. 9) where the movable lever member 14b is positioned, using the plane of the obliquely disposed tray 11 as a reference. For that reason, even if the tray 11 is completely filled with sheets, the first preventing means 16, and the plate-shaped member 32 do not interfere with the sheets on the tray. They neither disrupt the alignment of the sheets on the tray, nor damage the sheets on the tray, nor invite sheet discharging problems. Therefore, it is possible to always accurately detect the full load which is the maximum stacking amount of sheets on the tray.

Still further, the weight members 15 and movable lever member 14 are equipped in pairs in the width direction of discharging sheets at the same discharge outlet for the multi-bin sorter 10 of the present invention. Because the weight member 15 and the movable lever members 14 act to push discharging sheets downward, they improve the alignment of sheets discharged to the tray 11. Because the movable lever members 14 and the weight members 15 are each fixed to the different shaft 24 and the shaft 28 independently and freely rotate, it is possible to apply an appropriate amount of pushing force downward toward the tray 11 even for curls that occur with different sizes at both ends in the sheet width direction of the leading end and trailing end of sheets when discharged.

Additionally, the multi-bin sorter 10 according to this embodiment of the present invention uses the same members for the first preventing means 16, the second preventing means 17, the movable lever members 14b and 14c, and the weight members 15b and 15c, so this translates into reduced costs because parts control is simplified.

Note that an embodiment of the present invention has been described in terms of an example as applied to a multi-function device on the image forming apparatus 1. However, the invention is not limited to this, and can be properly applied to a device that outputs sheets formed thereupon with images and characters. Also, the example describes the maximum amount of sheets stacked on each tray, but the invention is by no means limited to that disclosure.

This embodiment of the present invention provides one example of a configuration of three bins of tray 11a, 11b, and 11c as the trays for stacking discharged sheets. However, the invention is not limited to the number of trays (or bins) described herein. It is also perfectly acceptable for the tray configuration to be applied to one or two trays. Also, the embodiment provides an example using the same parts for the movable lever members 14b and 14c, and the weight members 15b and 15c. Again the invention is not limited thereto and can use different shapes for each. The plate-shaped member 32 described in this embodiment has a freely rotating configuration within a 130° angle, but again this is not a limitation. This can be set to any desired angle (or rotating region). Also, this embodiment provided an example of a protective structure of a simple plate shape for the movable lever member 14a and weight member 15a, but in the same way as for the function of the fastening member 43, it is also perfectly acceptable to apply a protective structure of continuous or separate plate shapes to cover the movable lever member 14a and weight member 15a.

The present application claims the right of priority based on Japanese Patent Application Nos. 2005-129050 and 2005-129105 each filed Apr. 27, 2005, and incorporated by reference herein.

Claims

1. A sheet discharge tray for stacking discharged sheets, comprising:

a detachable member detachably mounted to a main unit from which the sheets are discharged; and

a fastening member, attached to the main unit, for fastening the detachable member to the main unit.

2. The sheet discharge tray according to claim 1, further comprising a static electricity discharging member for removing static electricity from discharged sheets, said static electricity discharging member being disposed at a bottom surface of the fastening member.

3. The sheet discharge tray according to claim 1, further comprising a lever sensor composed of a rotatable, movable lever member for touching a top surface of a discharged sheet, and a sensor member for detecting a discharge sheet stacking amount upon rotation of the movable lever member,

wherein the fastening member is disposed above the lever sensor.

4. The sheet discharge tray according to claim 3, further comprising a weight member for pushing discharging sheets downward,

wherein the fastening member is provided in a pair with the movable lever member in a width direction of the discharged sheets, and disposed above the weight member.

5. The sheet discharge tray according to claim 1, wherein the fastening member comprises, on a bottom surface thereof, a plurality of ribs for guiding discharged sheets.

6. The sheet discharge tray according to claim 5, wherein the detachable member comprises a plurality of ribs for connecting with the plurality of ribs on the fastening member when mounted to the main unit.

7. A multi-bin sorter comprising:

a plurality of sheet discharge trays for stacking, in a vertical direction, sheets discharged from a sheet discharge outlet of a main unit, with each of the trays comprising a detachable member detachably mounted to the main unit; and

a fastening member, attached to the main unit, for fastening the detachable member to the main unit.

8. The multi-bin sorter according to claim 7, wherein the fastening member is integrally provided with an upright surface of the sheet discharge outlet.

9. The multi-bin sorter according to claim 7, wherein the fastening member comprises, on a bottom surface thereof, a static electricity discharging mounting member for removing static electricity charged to discharging sheets, is integral to an upright surface of the sheet discharge outlet, and has a projecting shape for protecting members positioned below, from above.

10. The multi-bin sorter according to claim 7, further comprising a rotatable, movable lever member provided near the sheet discharge outlet for touching a top surface of a sheet stacked on the sheet discharge tray and rotating thereat;

a sensor for detecting a stacking state of the sheet stacked on the sheet discharge tray upon rotation of the movable lever member; and

first preventing means provided at a space above the sheet discharge tray at a downstream side in a direction of sheet discharge of the movable lever member, for preventing insertion of a sheet above the movable lever member in a direction opposite to the direction of sheet discharge.

11. The multi-bin sorter according to claim 10, wherein the first preventing means has a rotatable plate-shaped member capable of rotating freely within a predetermined first rotatable angle in a first direction rotating by contact with a sheet discharged from the sheet discharge outlet, and a second rotatable angle of the plate-shaped member, in a second direction opposite to the first direction, is controlled to be smaller than the first rotatable angle, when a sheet contacts the plate-shaped member in a direction opposite to the direction of the sheet discharge.

12. The multi-bin sorter according to claim 10, wherein the first preventing means comprises a plate-shaped member with a rotating shaft having a projection formed on an end thereof, a rotating range of the plate-shaped member being controlled at a predetermined angle, and a supporting member that pivotally supports the rotating shaft, the projection capable of contacting a portion of an inner wall of a bearing of the support member to control a range of rotation of the plate-shaped member.

13. The multi-bin sorter according to claim 12, wherein the sheet discharge tray is obliquely arranged with respect to the main unit, and a bottom end position of the plate-shaped member is higher, with reference to a plane of the tray, than a sheet stacking amount detection position at which the movable lever member is positioned when a sheet maximum stacking amount is detected by the sensor.

14. The multi-bin sorter according to claim 12, wherein the plate-shaped member hangs in a substantially vertical posture under its own weight.

15. The multi-bin sorter according to claim 14, wherein the plate-shaped member is arranged to be able, if a sheet is manually inserted in a direction opposite to the direction of sheet discharge and an end of the inserted sheet touches the plate-shaped member, to rotate from the substantially vertical posture to the predetermined angle in the second direction such that the rotation is controlled and so as to guide the sheet toward the tray.

16. The multi-bin sorter according to claim 10, wherein the first preventing means comprises a support member with a projection provided at an end thereof, and

the main unit comprises a concave portion provided in a wall thereof so that the projection of the support member is detachably inserted into the concave portion to position the first preventing means at a predetermined position.

17. The multi-bin sorter according to claim 10, further comprising a weight member provided rotatably near the sheet discharge outlet and at an opposite side of the movable lever member interposed by the sheet discharge outlet, said weight member pushing the sheet ejected from the sheet discharge outlet downwardly, and

second preventing means provided at a space above the tray at a downstream side in the direction of sheet discharge of the weight member, for preventing insertion of a sheet above the weight member in a direction opposite to the sheet discharge direction.

18. The multi-bin sorter according to claim 17, wherein the movable lever member and weight member are substantially the same shape, and are provided as a pair in a direction that intersects the sheet discharge direction.

19. The multi-bin sorter according to claim 18, wherein the first and second preventing means are substantially the same shape.