Patent Grant
6957810
1. Field of the Invention
The present invention relates to a sheet finisher mounted on or operatively connected to a copier, printer or similar image forming apparatus for sorting, stacking, stapling, punching, positioning, folding or otherwise finishing a sheet or sheets carrying images thereon, and an image forming system consisting of the sheet finisher and an image forming apparatus.
2. Description of the Background Art
Today, a sheet finisher for the above application is extensively used and located downstream of an image forming apparatus for finishing sheets, or recording media, in various ways. An advanced finisher recently proposed has multiple functions including a center stapling function and a folding function in addition to an edge stapling function. Japanese Patent Laid-Open Publication No. 2001-19269, for example, discloses a sheet finisher including a rollet pair configured to fold a sheet stack at the center while conveying the sheet stack via its nip.
Japanese Patent Laid-Open Publication Nos. 7-48062 and 2000-153947, for example, each disclose a sheet finisher in which edge stapling and center stapling are effected independently of each other with a sheet path being switched at the inlet of the finisher. Although this type of sheet finisher can be easily constructed into a unit and can adapt to a less-option configuration, it is not desirable in the cost aspect because its functions overlap each other. Further, in a center staple mode, the sheet finisher performs folding of a sheet stack at the same position as positioning and stapling, so that a sheet stack of the next job cannot be brought to the center stapling position until the folding of the previous job completes. This prevents productivity from being enhanced.
In light of the above, Japanese Patent Laid-Open Publication Nos. 2000-11886 and 7-187479, for example, each teach a sheet finisher including a staple tray or processing tray inclined such that its downstream side in the direction of sheet feed is higher in level than the upstream side. A sheet stack is positioned and stapled on such a staple tray in either one of an edge staple mode and a center staple mode and then switched back to be conveyed to another station, which is assigned to folding. More specifically, the stapled sheet stack is conveyed in a direction opposite to a direction in which a sheet stack stapled at its edge is to be discharged. The folding station arranged independently of the stapling station enhances productivity and minimizes an increase in cost ascribable to overlapping mechanisms. However, a fold tray located at the folding station must be configured long enough to enhance productivity. As a result, the staple tray positioned above the fold tray and the fold tray are contiguous with each other in a “<” configuration, making the sheet finisher bulky. This cannot meet the increasing demand for space saving.
For size reduction, Japanese Patent Laid-open Publication No. 2000-63031, for example, proposes a sheet finisher constructed to fold a sheet stack extending over two processing trays. This construction, however, cannot enhance productivity.
Japanese Patent Laid-Open Publication Nos. 11-286368 and 2000-86067 each propose a sheet finisher in which a fold roller is positioned slightly above the intermediate portion of a fold tray so as to directly fold a sheet stack and then drive it out of the finisher, thereby implementing the shared use of a processing tray and a short conveyance path. Such a sheet finisher, however, not only fails to enhance productivity, as stated earlier, but also is large size because the fold roller is positioned above the inclined tray.
Of course, a sheet finisher with a single function, i.e., a center stapling function, as disclosed in Japanese Patent Laid-Open Publication No. 9-183558, cannot meet the needs on today's market.
Generally, in a staple mode available with a sheet finisher, it is a common practice to position consecutive sheets on a position tray, staple the resulting sheet stack with stapling means, and then convey the stapled sheet stack to a tray located at the most downstream portion of the sheet finisher. In a center staple mode, a sheet stack stapled at the center is conveyed to a folding section and then conveyed to the above tray. This type of sheet finisher includes a plurality of paths each being assigned to a particular mode and path switching means for selecting one of the paths matching with a mode selected.
When the sheet finisher with the folding function stated above conveys a sheet stack to a folding station, the sheet stack is apt to become loose if conveyed at high speed although the speed may allow a stapled sheet stack to be surely conveyed. The loose sheet stack cannot be stapled in a neat configuration. However, if the conveying speed is lowered, then the next sheet stack (job) cannot be received. This lowers CPM and therefore requires the productivity of the image forming apparatus to be lowered. That is, how high the operation speed of the image forming apparatus may be, the productivity of the image forming apparatus is limited by the ability of the sheet finisher.
Assume that the path switching means is operated when a job for outputting a desired number of sets (copies) of copies of documents or outputting a plurality of booklets is to be executed. For example, assume that in a center staple mode the path switching means selects a path for conveying a sheet stack downward from a staple tray instead of a path for conveying it upward from the staple tray. Then, the path switching means catches a sheet entering the staple tray and causes it to jam the path or to crease or otherwise deform. Further, if the path switching means is so positioned as to select the downward path when a sheet stack jams the path at a branch portion, it is difficult for the operator to remove the jamming sheet stack.
Moreover, in the case where a sheet stack includes a cover or a slip sheet different in kind and size from the other sheets, a roller or a projection included in the path switching means is likely to catch the sheet stack and damage it. More specifically, the size of a sheet varies when it is passed through a fixing section in accordance with the degree of moisture absorption.
Technologies relating to the present invention are also disclosed in, e.g., Japanese Patent Laid-Open Publication Nos. 10-59610, 10-181990, 10-218475, 2000-72320, 2000-118860, 2000-143081 and 2000-68577.
It is an object of the present invention to provide a sheet finisher that is low cost and highly productive and space-saving, and an image forming system using the same.
It is another object of the present invention to provide a sheet finisher capable of obviating sheet jams, creases and scratches during operation and facilitating jam processing in the case of a sheet jam, and an image forming system using the same.
A sheet finisher for executing preselected processing with a sheet conveyed thereto of the present invention includes a first processing tray configured to temporarily store the sheet and deliver it. A first and a second path are positioned downstream of the first processing tray in a direction of sheet conveyance and configured to convey a first and a second sheet stack, respectively. The first path conveys the first sheet stack upward over the downstream portion of the first processing tray while the second path conveys it downward over the same. A switching device selects either one of the first and second paths.
An image forming system including the above sheet finisher and an image forming apparatus is also disclosed.
The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description taken with the accompanying drawings in which:
Referring to
Sheets sequentially brought to the staple tray F via the paths A and D are positioned one by one, stapled or otherwise processed, and then steered by a guide plate 54 and a movable guide 55 to either one of the path C and another processing tray G. The processing tray G folds or otherwise processes the sheets and, in this sense, will sometimes be referred to as a fold tray hereinafter. The sheets folded by the fold tray G are guided to a lower tray 203 via a path H. The path D includes a path selector 17 constantly biased to a position shown in
On the path A merging into the paths B, C and D, there are sequentially arranged an inlet sensor 301 responsive to a sheet coming into the finisher PD, an inlet roller pair 1, the punch unit 100, a waste hopper 101, roller pair 2, and the path selectors 15 and 16. Springs, not shown, constantly bias the path selectors 15 and 16 to the positions shown in FIG. 1. When solenoids, not shown, are energized, the path selectors 15 and 16 rotate upward and downward, respectively, to thereby steer the sheet to desired one of the paths B, C and D.
More specifically, to guide a sheet to the path B, the path selector 15 is held in the position shown in
In the illustrative embodiment, the finisher PD is capable of selectively effecting punching (punch unit 100), jogging and edge stapling (jogger fence 53 and edge stapler S1), sorting (shift tray 202) or folding (fold plate 74 and fold rollers 81 and 82), as desired.
The image forming apparatus PR uses a conventional electrophotographic process that forms a latent image on the charged surface of a photoconductive drum or similar image carrier with a light beam in accordance with image data, develops the latent image with toner, transfers the resulting toner image to a sheet or recording medium, and fixes the toner image on the sheet. Such a process is well known in the art and will not be described in detail. Of course, the illustrative embodiment is similarly applicable to any other image forming apparatus, e.g., an ink jet printer.
A shift tray outlet section I is located at the most downstream position of the sheet finisher PD and includes a shift outlet roller pair 6, a return roller 13, a sheet surface sensor 330, and the shift tray 202. The shift tray outlet section I additionally includes a shifting mechanism J shown in
As shown in
As shown in
More specifically, in the illustrative embodiment, the sensors 330a and 330b each turn on when interrupted by the interrupter 30b of the lever 30. Therefore, when the shift tray 202 is lifted with the contact end 30a of the lever 30 moving upward, the sensor 330a turns off. As the shift tray 202 is further lifted, the sensor 330b turns off. When the outputs of the sensors 330a and 330b indicate that sheets are stacked on the shift tray 202 to a preselected height, the tray elevation motor 168 is driven to lower the shift tray 202 by a preselected amount. The top of the sheet stack on the shift tray 202 is therefore maintained at a substantially constant height.
The shift tray elevating mechanism K will be described in detail with reference to FIG. 3. As shown, the mechanism K includes a drive unit L for moving the shift tray 202 upward or downward via a drive shaft 21. Timing belts 23 are passed over the drive shaft 22 and a driven shaft 22 under tension via timing pulleys. A side plate 24 supports the shift tray 202 and is affixed to the timing belts 23. In this configuration, the entire unit including the shift tray 202 is supported by the timing belts 23 in such a manner as to be movable up and down.
The drive unit L includes a worm gear 25 in addition to the tray elevation motor 168, which is a reversible drive source. Torque output from the tray elevation motor 168 is transmitted to the last gear of a gear train mounted on the drive shaft 21 to thereby move the shift tray 202 upward or downward. The worm gear 25 included in the driveline allows the shift tray 202 to be held at a preselected position and therefore prevents it from dropping by accident.
An interrupter 24a is formed integrally with the side plate 24 of the shift tray 202. A full sensor 334 responsive to the full condition of the shift tray 202 and a lower limit sensor 335 responsive to the lower limit position of the shift tray 202 are positioned below the interrupter 24a. The full sensor 334 and lower limit sensor 335, which are implemented by photosensors, each turn off when interrupted by the interrupter 24a. In
As shown in
Guide channels 32c are formed in the front surface of the end fence 32. The rear edge portions of the shift tray 202 are movably received in the guide channels 32c. The shift tray 202 is therefore movable up and down and movable back and forth in the direction perpendicular to the direction of sheet discharged, as needed. The end fence 32 guides the trailing edges of sheets stacked on the shift tray 202 for thereby aligning them.
As shown in
As shown in
More specifically, torque output from the discharge motor 157 is transferred to the discharge belt 52 via a timing belt and the timing pulley 62. The timing pulley (drive pulley) 62 and discharge rollers 56 are mounted on the same shaft, i.e., the discharge shaft 65. An arrangement may be made such that when the relation in speed between the discharge rollers 56 and the discharge belt 52 should be varied, the discharge rollers 56 are freely rotatable on the discharge shaft 65 and driven by part of the output torque of the discharge motor 157. This kind of scheme allows a desired reduction ratio to be set up.
The surface of the discharge roller 56 is formed of rubber or similar high-friction material. The discharge roller 56 nips a sheet stack between it and a press roller or driven roller 57 due to the weight of the driven roller 57 or a bias, thereby conveying the sheet stack.
A processing mechanism will be described hereinafter. As shown in
As shown in
As shown in
As shown in
There are also shown in
Reference will be made to
As shown in
The movable guide 55 is angularly movably mounted on the shaft of the discharge roller 56. A link arm 60 is connected to one end of the movable guide 55 remote from the guide plate 54 at a joint 60a. A pin studded on the front side wall 64a,
When the leading edge of a sheet stack steered by the guide plate 54 contacts the guide surface 55a of the movable guide 55, the guide surface 55a causes the leading edge to make a hairpin turn with a small diameter R. When the can 61 is in the home position, the movable guide 55 abuts against a plate, not shown, and biased by the spring 59 in the counterclockwise direction.
In the condition shown in
In the condition shown in
Although the path selectors 15 and 16 shown in
While in the illustrative embodiment the guide plate 54 and movable guide 55 share a single drive motor, each of them may be driven by a respective drive motor, so that the timing of movement and stop position can be controlled in accordance with the sheet size and the number of sheets stapled together.
The fold tray G will be described specifically with reference to
A fold plate motor 166 causes the fold plate cam 75 to rotate in a direction indicated by an arrow in FIG. 13. The stop position of the fold plate cam 75 is determined on the basis of the output of a fold plate HP sensor 325 responsive to the opposite ends of a semicircular interrupter portion 75a included in the cam 75.
While the illustrative embodiment is assumed to fold a sheet stack at the center, it is capable of folding even a single sheet at the center. In such a case, because a is single sheet does not have to be stapled at the center, it is fed to the fold tray G as soon as it is driven out, folded by the fold plate 74 and fold roller pair 81, and then delivered to the lower tray 203, FIG. 1.
The angle of the staple tray F should preferably be as small as possible in order to reduce the projection area in the vertical direction and therefore the area to be occupied by the sheet finisher PD. However, in the illustrative embodiment, the fold plate 74, link arm 76, fold plate cam 75 and fold plate motor 166 constituting the folding mechanism of
To fold a sheet stack at the centers the center of the sheet stack should be coincident with a folding position assigned to the fold plate 74, as will be described specifically later. For this purpose, in the illustrative embodiment, a movable rear fence 73 is included in the lower guide plate 91 such that the trailing edge of a folded sheet stack (leading edge when the sheet stack is to be conveyed) rests on the fence 73. The movable rear fence 73 is movable upward or downward to bring the center of the sheet stack resting thereon to the folding position.
As shown in
As shown in
The unit U having the above configuration can be pulled out in the event of a jam and allows a jamming sheet to be easily removed. More specifically, when a jam occurs at the fold tray G side, the operator should only pull out the unit U halfway and can rapidly deal with the jam while watching the guide plates 91 and 92 opened away from each other. After the jam processing, when the operator pushes the unit U into the finisher PD, the guide plates 91 and 92 are automatically closed by the edges of the opening 67 and locked by the magnet. This obviates an occurrence that the operator fails to close the guide plates 91 and 92 and makes the next step impracticable.
While the guide rails 66 are positioned at the fold tray G side of the opening 67, they may, of course, be located at any other position, e.g., a position above the guide plates 91 and 92.
In the illustrative embodiment, the staple tray F is inclined by a large angle in relation to the fold tray G and folding mechanism, i.e., positioned obliquely at as small an angle as possible relative to the fold tray G, as stated earlier. In this arrangement, the fold tray G is positioned below the staple tray F, so that the space above the staple tray F is questionable in the aspect of efficient use of space. In light of this, in the illustrative embodiment, the path D and prestacking portion E are positioned in parallel to the staple tray F while a waste receiver 101a included in the waste unit 101 is held in an inclined position in the space available in the upper right portion, as seen in FIG. 1. This promotes the efficient use of the limited space available in the finisher PD.
In the above configuration, if the sheet size is large, then a sheet stored in the prestacking portion E waits for the next sheet with its trailing edge in the direction of sheet conveyance protruding from the portion E. At this instant, because the sheet prestacking portion E is positioned in the upper right portion of the finisher PD, a sufficient space is available below the portion E and prevents the sheet from jamming the path.
Further, the folding mechanism of the fold tray G is located between the edge stapler S1 and the center staplers S2, so that a sufficient space is available below the fold plate 74 even when the sheet size is large. Therefore, a sufficient space is guaranteed below the leading edge of a sheet despite that the sheet is conveyed vertically along the guide plates 91 and 92.
Reference will be made to
The CPU 360 controls, based on the above various inputs, the tray motor 168 assigned to the shift tray 202, the guide plate motor 167 assigned to the guide plate, the shift motor 169 assigned to the shift tray 202, a knock roller motor, not shown, assigned to the knock roller 12, various solenoids including the knock solenoid (SOL) 170, motors for driving the conveyor rollers, outlet motors for driving the outlet rollers, the discharge motor 157 assigned to the belt 52, the stapler motor 159 assigned to the edge stapler S1, the jogger motor 158 assigned to the jogger fences 53, the steer motor 161 assigned to the guide plate 54 and movable guide 55, a motor, not shown, assigned to rollers for conveying a sheet stack, a rear fence motor assigned to the movable rear fence 73, and a fold roller motor, not shown, assigned to the fold roller 81. The pulse signals of a staple conveyance motor, not shown, assigned to the staple discharge rollers are input to the CPU 360 and counted thereby. The CPU 360 controls the knock SOL 170 and jogger motor 158 in accordance with the number of pulse signals counted.
Further, the CPU 360 causes the punch unit 100 to operate by controlling a clutch or a motor. The CPU 360 controls the finisher PD in accordance with a program stored in a ROM (Read Only Memory), not shown, by using a RAM (Random Access Memory) as a work area.
Specific operations to be executed by the CPU 360 in various modes available with the illustrative embodiment will be described hereinafter.
First, in a non-staple mode A, a sheet is conveyed via the paths A and H to the upper tray 201 without being stapled. To implement this mode, the path selector 15 is moved clockwise, as viewed in
As shown, before a sheet driven out of the image forming apparatus PR enters the finisher PD, CPU 360 causes the inlet roller pair 1 and conveyor roller pair 2 on the path A to start rotating (step S101). The CPU 360 then checks the ON/OFF state of the inlet sensor 301 (steps S102 and S103) and the ON/OFF state of the upper outlet sensor 302 (steps S014 and S105) for thereby confirming the passage of sheets. When a preselected period of time elapses since the passage of the last sheet (YES, step S106), the CPU 360 causes the above rollers to stop rotating (step S107). In this manner, all the sheets handed over from the image forming apparatus PR to the finisher PD are sequentially stacked on the upper tray 201 without being stapled. If desired, the punch unit 100, which intervenes between the inlet roller pair 1 and conveyor roller pair 2, may punch the consecutive sheets.
In a non-staple mode B, the sheets are routed through the paths A and C to the shift tray 202. In this mode, the path selectors 15 and 16 are respectively moved counterclockwise and clockwise, unblocking the path C. The non-staple mode B will be described with reference to
As shown, before a sheet driven out of the image forming apparatus PR enters the finisher PD, CPU 360 causes the inlet roller pair 1 and conveyor roller pair 2 on the path A and the conveyor roller pair 5 and shift outlet roller pair 6 on the path C to start rotating (step S201). The CPU 360 then energizes the solenoids assigned to the path selectors 15 and 16 (step S202) to thereby move the path selectors 15 and 16 counterclockwise and clockwise, respectively. Subsequently, the CPU 360 checks the ON/OFF state of the inlet sensor 301 (steps S203 and S204) and the ON/OFF state of the shift outlet sensor 303 (steps S205 and S206) to thereby confirm the passage of the sheets.
On the elapse of a preselected period of time since the passage of the last sheet (YES, step S207), the CPU 360 causes the various rollers mentioned above to stop rotating (S208) and deenergizes the solenoids (steps S209). In this manner, all the sheets entered the finisher PD are sequentially stacked on the shift tray 202 without being stapled. Again, the punch unit 100 intervening between the inlet roller pair 1 and conveyor roller pair 2 may punch the consecutive sheets, if desired.
In a sort/stack mode, the sheets are also sequentially delivered from the path A to the shift tray 202 via the path C. A difference is that the shift tray 202 is shifted perpendicularly to the direction of sheet discharge copy by copy in order to sort the sheets. The path selectors 15 and 16 are respectively rotated counterclockwise and clockwise as in the non-staple mode B, thereby unblocking the path C. The sort/stack mode will be described with reference to
As shown, before a sheet driven out of the image forming apparatus PR enters the finisher PD, CPU 360 causes the inlet roller pair 1 and conveyor roller pair 2 on the path A and the conveyor roller pair 5 and shift outlet roller pair 6 on the path C to start rotating (step S301). The CPU 360 then energizes the solenoids assigned to the path selectors 15 and 16 (step S302) to thereby move the path selectors 15 and 16 counterclockwise and clockwise, respectively. Subsequently, the CPU 360 checks the ON/OFF state of the inlet sensor 301 (steps S303 and S304) and the ON/OFF state of the shift outlet sensor 303 (step S305).
If the sheet passed the shift outlet sensor 303 is the first sheet of a copy (YES, step S306), then the CPU 360 turns on the shift motor 169 (step S307) to thereby move the shift tray 202 perpendicularly to the direction of sheet conveyance until the shift sensor 336 senses the tray 202 (steps S308 and S309). When the sheet moves away from the shift outlet sensor 303 (YES, step S310), the CPU 360 determines whether or not the sheet is the last sheet (step S311). If the answer of the step S311 is NO, meaning that the sheet is not the last sheet of a copy, and if the copy is not a single sheet, then the procedure returns to the step S303. If the copy is a single sheet, then the CPU 360 executes a step S312.
If the answer of the step S306 is NO, meaning that the sheet passed the shift outlet sensor 303 is not the first sheet of a copy, then the CPU 360 discharges the sheet (step S310) because the shift tray 202 has already been shifted. The CPU 360 then determines whether or not the discharged sheet is the last sheet (step S311). If the answer of the step S311 is NO, then the CPU 360 repeats the step S303 and successive steps with the next sheet. If the answer of the step S311 is YES, then the CPU 360 causes, on the elapse of a preselected period of time, the inlet roller pair 1, conveyor roller pairs 2 and 5 and shift outlet roller pair 6 to stop rotating (step S312) and deenergizes the solenoids assigned to the path selectors 15 and 16 (step S313). In this manner, all the sheets sequentially entered the finisher PD are sorted and stacked on the shift tray 202 without being stapled. In this mode, too, the punch unit 100 may punch the consecutive sheets, if desired.
In a staple mode, the sheets are conveyed from the path A to the staple tray F via the path D, positioned and stapled on the staple tray F, and then discharged t the shift tray 202 via the path C. In this mode, the path selectors 15 and 16 both are rotated counterclockwise to unblock the route extending from the path A to the path D. The staple mode will be described with reference to
As shown, before a sheet driven out of the image forming apparatus PR enters the finisher PD, CPU 360 causes the inlet roller pair 1 and conveyor roller pair 2 on the path A and the conveyor roller pairs 7, 9 and 10 and staple outlet roller 11 on the path D and knock roller 12 to start rotating (step S401). The CPU 360 then energizes the solenoid assigned to the path selector 15 (step S402) to thereby cause the path selector 15 to rotate counterclockwise.
After the stapler HP sensor 312 has sensed the edge stapler S1 at the home position, the CPU 360 drives the stapler motor 159 to move the edge stapler S1 to a preselected stapling position (step S403). Also, after the belt HP sensor 311 has sensed the belt 52 at the home position, the CPU 360 drives the discharge motor 157 to bring the belt 52 to a stand-by position (step S404). Further, after the jogger fence motor HP sensor has sensed the jogger fences 53 at the home position, the CPU 360 moves the jogger fences 53 to a stand-by position (step S405). In addition, the CPU 360 causes the guide plate 54 and movable guide 55 to move to their home positions (step S406).
If the inlet sensor 301 has turned on (YES, step S407) and then turned off (YES, step S408), if the staple discharge sensor 305 has turned on (YES, step S409) and if the shift outlet sensor 303 has tuned on (YES, step S410) then the CPU 360 determines that a sheet is present on the staple tray F. In this case, the CPU 360 energizes the knock solenoid 170 for a preselected period of time to cause the knock roller 12 to contact the sheet and force it against the rear fences 51, thereby positioning the rear edge of the sheet (step S411). Subsequently, the CPU 360 drives the jogger motor 158 to move each jogger fence 53 inward by a preselected distance for thereby positioning the sheet in the direction of width perpendicular to the direction of sheet conveyance and then returns the jogger fence 53 to the stand-by position (step S412). The CPU 360 repeats the step S407 and successive steps with every sheet. When the last sheet of a copy arrives at the staple tray F (YES, step S413), the CPU 360 moves the jogger fences 53 inward to a position where they prevent the edges of the sheets from being dislocated (step S414). In this condition, the CPU 360 turns on the stapler S1 and causes it to staple the edge of the sheet stack (step S415).
On the other hand, the CPU 360 lowers the shift tray 202 by a preselected amount (step S416) in order to produce a space for receiving the stapled sheet stack. The CPU 360 then drives the shift discharge roller pair 6 via the shift discharge motor (step S417) and drives the belt 52 by a preselected amount via the discharge motor 157 (step S418), so that the stapled sheet stack is raised toward the path C. As a result, the stapled sheet stack is driven out to the shift tray 202 via the shift outlet roller pair 6. After the shift outlet sensor 303 has turned on (step S419) and then turned off (step S420), meaning that the sheet stack has moved away from the sensor 303, the CPU 360 moves the belt 52 and jogger fences 53 to their stand-by positions (steps S421 and S422), causes the shift outlet roller pair 6 to stop rotating on the elapse of a preselected period of time (step S423), and raises the shift tray 202 to a sheet receiving position (step S424). The rise of the shift tray 202 is controlled in accordance with the output of the sheet surface sensor 330 responsive to the top of the sheet stack positioned on the shift tray 202.
After the last copy or set of sheets has been driven out to the shift tray 202, the CPU 360 returns the edge stapler S1, belt 52 and jogger fences 53 to their home positions (steps S426, S427 and S428) and causes the inlet roller pair 1, conveyor roller pairs 2, 7, 9 and 10, staple discharge roller pair 11 and knock roller 12 to stop rotating (step S429). Further, the CPU 360 deenergizes the solenoid assigned to the path selector 15 (step S430. Consequently, all the structural parts are returned to their initial positions. In this case, too, the punch unit 100 may punch the consecutive sheets before stapling.
The operation of the staple tray F in the staple mode will be described more specifically hereinafter. As shown in
The staple discharge sensor 305 senses the trailing edge of the sheet and sends its output to the CPU 360. In response, the CPU 360 starts counting drive pulses input to the staple motor, not shown, driving the staple discharge roller pair 11. On counting a preselected number of pulses, the CPU 360 energizes the knock solenoid 170 (step S412). The knock solenoid 170 causes the knock roller 12 to contact the sheet and force it downward when energized, so that the sheet is positioned by the rear fences 51. Every time a sheet to be stacked on the staple tray F1 passes the inlet sensor 301 or the staple discharge sensor 305, the output of the sensor 301 or 305 is sent to the CPU 360, causing the CPU 360 to count the sheet.
On the elapse of a preselected period of time since the knock solenoid 170 has been turned off, the CPU 360 causes the jogger motor 159 to move each jogger fence 53 further inward by 2.6 mm and then stop it, thereby positioning the sheet in the direction of width. Subsequently, the CPU 360 moves the jogger fence 53 outward by 7.6 mm to the stand-by position and then waits for the next sheet (step S412). The CPU 360 repeats such a procedure up to the last page (step S413). The CPU 360 again causes the jogger fences 53 to move inward by 7 mm and then stop, thereby causing the jogger fences 53 to retain the opposite edges of the sheet stack to be stapled. Subsequently, on the elapse of a preselected period of time, the CPU 360 drives the edge stapler S1 via the staple motor for thereby stapling the sheet stack (step S415). If two or more stapling positions are designated, then the CPU 360 moves, after stapling at one position, the edge stapler S1 to another designated position along the rear edge of the sheet stack via the stapler motor 159. At this position, the edge stapler S1 again staples the sheet stack. This is repeated when three or more stapling positions are designated.
After the stapling operation, the CPU 360 drives the belt 52 via the discharge motor 157 (step S418). At the same time, the CPU 360 drives the outlet motor to cause the shift outlet roller pair 6 to start rotating in order to receive the stapled sheet stack lifted by the hook 52a (step S417). At this instants the CPU 360 controls the jogger fences 53 in a different manner in accordance with the sheet size and the number of sheets stapled together. For example, when the number of sheets stapled together or the sheet size is smaller than a preselected value, then the CPU 360 causes the jogger fences 53 to constantly retain the opposite edges of the sheet stack until the hook 52a fully lifts the rear edge of the sheet stack. When a preselected number of pulses are output since the turn-on of the sheet sensor 310 or the belt HP sensor 311, the CPU 360 causes the jogger fences 53 to retract by 2 mm and release the sheet stack. The preselected number of pulses corresponds to an interval between the time when the hook 52a contacts the trailing edge of the sheet stack and the time when it moves away from the upper ends of the jogger fences 53.
On the other hand, when the number of sheets stapled together or the sheet size is larger than the preselected value, the CPU 360 causes the jogger fences 53 to retract by 2 mm beforehand. In any case, as soon as the stapled sheet stack moves away from the jogger fences 53, the CPU 360 moves the jogger fences 53 further outward by 5 mm to the stand-by positions (step S422) for thereby preparing it for the next sheet. If desired, the restraint to act on the sheet stack may be controlled on the basis of the distance of each jogger fence from the sheet stack.
In a center staple and bind mode, the sheets are sequentially conveyed from the path A to the staple tray F via the path D, positioned and stapled at the center on the tray F, folded on the fold tray G, and then driven out to the lower tray 203 via the path H. In this mode, the path selectors 15 and 16 both are rotated counterclockwise to unblock the route extending from the path A to the path D. Also, the guide plate 54 and movable guide plate 55 are closed, as shown in
As shown, before a sheet driven out of the image forming apparatus PR enters the finisher PD, CPU 360 causes the inlet roller pair 1 and conveyor roller pair 2 on the path A and the conveyor roller pairs 7, 9 and 10 and staple outlet roller 11 on the path D and knock roller 12 to start rotating (step S401). The CPU 360 then energizes the solenoid assigned to the path selector 15 (step S402) to thereby cause the path selector 15 to rotate counterclockwise.
Subsequently, after the belt HP sensor 311 has sensed the belt 52 at the home position, the CPU 360 drives to the discharge motor 157 to move the belt 52 to the stand-by position (step S503). Also, after the jogger fence HP sensor has sensed each jogger fence 53 at the home position, the CPU 360 moves the jogger fence 53 to the stand-by position (step S504). Further, the CPU 360 moves the guide plate 54 and movable guide 55 to their home positions (steps S505).
If the inlet sensor 301 has turned on (YES, step S506) and then turned off (YES, step S507), if the staple discharge sensor 305 has turned on (YES, step S508) and if the shift outlet sensor 303 has tuned on (YES, step S509), then the CPU 360 determines that a sheet is present on the staple tray F. In this case, the CPU 360 energizes the knock solenoid 170 for the preselected period of time to cause the knock roller 12 to contact the sheet and force it against the rear fences 51, thereby positioning the trailing edge of the sheet (step S510). Subsequently, the CPU 360 drives the jogger motor 158 to move each jogger fence 53 inward by the preselected distance for thereby positioning the sheet in the direction of width perpendicular to the direction of sheet conveyance and then returns the jogger fence 53 to the stand-by position (step S511). The CPU 360 repeats the step S407 and successive steps with every sheet. When the last sheet of a copy arrives at the staple tray F (YES, step S512), the CPU 360 moves the jogger fences 53 inward to the position where they prevent the edges of the sheets from being dislocated (step S513).
After the, step S513, the CPU 360 turns on the discharge motor 157 to thereby move the belt 52 by a preselected amount (step S514), so that the belt 52 lifts the sheet stack to a stapling position assigned to the center staplers S2. Subsequently, the CPU 360 turns on the center staplers S2 at the intermediate portion of the sheet stack for thereby stapling the sheet stack at the center (step S515). The CPU 360 then moves the guides 54 and 55 by a preselected amount each in order to form a path directed toward the fold tray G (step S516) and causes the upper and lower roller pairs 71 and 72 of the fold tray G to start rotating (step S517). As soon as the movable rear fence 73 of the fold tray G is sensed at the home position, the CPU 360 moves the fence 73 to a stand-by position (step S518). The fold tray G is now ready to receive the stapled sheet stack.
After the step S518, the CPU 360 further moves the belt 52 by a preselected amount (step S519) and cause a the discharge roller 56 and press roller 57 to nip the sheet stack and convey it to the fold tray G. When the leading edge of the stapled sheet stack is conveyed by a preselected distance past the stack arrival sensor 321 (step S520), the CPU 360 causes the upper and lower roller pairs 71 and 72 to stop rotating (step S521) and then releases the lower rollers 72 from each other. Subsequently, the CPU 360 causes the fold plate 74 start folding the sheet stack (step S523) and causes the fold roller pairs 81 and 82 and lower outlet roller pair 83 to start rotating (step S524). The CPU 360 then determines whether or not the folded sheet stack has moved away from the pass sensor 323 (steps S525 and S526). If the answer of the step S526 is YES, then the CPU 360 brings the lower rollers 72 into contact (step S527) and moves the guides 54 and 55 to their home positions (steps S528 and S529).
In the above condition, the CPU 360 determines whether or not the trailing edge of the folded sheet stack has moved away from the lower outlet sensor 324 (steps S530 and S531). If the answer of the step S531 is YES, then the CPU 360 causes the fold roller pairs 81 and 82 and lower outlet roller pair 83 to further rotate for a preselected period of time and then stop (step S532) and then causes the belt 52 and jogger fences 53 to return to the stand-by positions (steps S533 and S534). Subsequently, the CPU 360 determines whether or not the above sheet stack is the last copy of a single job (step S535). If the answer of the step S535 is NO, then the procedure returns to the step S506. If the answer of the step S535 is YES, the CPU 360 returns the belt 52 and jogger fences 53 to the home positions (steps S536 and S537). At the same time, the CPU 360 causes the staple discharge roller pair 11 and knock roller 12 to atop rotating (step S538) and turns off the solenoid assigned to the path selector 15 (step S539). As a result, all the structural parts are returned to their initial positions.
Hereinafter will be described the sheet stack steering mechanism and control over the movement of the belt 52.
As shown, the CPU 360 determines whether or not the guide. HP sensor 315 responsive to the interrupter 61c of the cam 61 has turned on (step S601). If the answer of the step S601 is YES, then the CPU 360 rotates the steer motor 161 counterclockwise, as indicated by an arrow in
On the other hand, if the guide HP sensor 315 has turned off (YES, step S605), the CPU 360 drives the steer motor 161 clockwise (step S605). When the guide HP sensor 315 turns on (YES, step S606), the CPU 360 stops driving the steer motor 161 (step S607) and again drives it counterclockwise (step S602) until the guide HP sensor 315 turns off (steps S603 and S604). Consequently, the initial position of the cam 61, i.e., the initial positions of the guide plate 54 and movable guide 55 are set.
As soon as the movement of the guides 54 and 55 completes (YES, step S709), the CPU 360 moves the belt 52 via the discharge motor 157 so as to discharge the sheet stack upward away from the center binding position (step S710). At this instant, the belt 52 once stops on moving a preselected distance matching with the sheet size (step S711). In this condition, the discharge roller 56 and press roller 57 and the upper and lower roller pairs 71 and 72 convey the sheet stack to the preselected folding position (step S712). Subsequently, the CPU 360 determines whether or not the next job to execute exists (step S712). If the answer of the step S712 is YES, then the CPU 360 moves the belt 52 to the stand-by position (see
The stapling operation and folding operation to be performed in the fold mode will be described in more detail hereinafter. A sheet is steered by the path selectors 15 and 16 to the path D and then conveyed by the roller pairs 7, 9 and 10 and staple discharge roller 11 to the staple tray F. The staple tray F operates in exactly the same manner as in the staple mode stated earlier before positioning and stapling (see FIG. 23). Subsequently, as shown in
Subsequently, as shown in
As shown in
As shown in
As shown in
Further, the second fold roller pair 82 and lower outlet roller pair 83 are located at a position protruded sideways from the housing side wall SBA, so that a stapled sheet stack can be sufficiently folded in a plurality of steps. In this case, because the sheet size is halved due to folding, the size of the lower tray 203 should only be one-half of the maximum size of a folded sheet stack. This makes it needless for the lower tray 203 to protrude over the outermost end of the shift tray 202 and therefore readily guarantees a space for accommodating the fold roller pair 82 and lower outlet roller pair 83. This is why the lower housing wall part SBB below the lowermost position assigned to the shift tray 202 protrudes sideways from the housing side wall SBA. Consequently, the folding mechanism with the sufficient folding function can be arranged in the lower portion of the finisher PD without increasing the vertical projection area.
Moreover, the shift tray 202 can move over a broad range extending from a position just above the outlet for a folded sheet stack to a position just below the outlet adjoining the outlet roller pair 6. Therefore, the shift tray 202 and lower tray 203 can be loaded with a large number of sheets each.
As stated above, in the illustrative embodiment, the staple tray F is sharply inclined to minimize the angle between it and the fold tray G while the folding mechanism is arranged between the trays F and G. A sheet stack is positioned and stapled on the staple tray F at the edge or the center and then folded, when stapled at the center, by the folding section. The stapling operation and folding operation can be effected in parallel. The illustrative embodiment therefore solves all the problems with the conventional sheet finisher, i.e., limitations on function, low productivity and bulky construction and thereby realizes a space-saving, highly productive sheet finisher.
The edge stapler S1 and center staplers S2 are configured independently of each other, so that either one of them suitable for desired processing is always positioned in the vicinity of the location where the jogger fences 53 positions a sheet. This successfully reduces the overall processing time necessary for positioning and stapling and therefore enhances productivity. In addition, the belt 52 and hook 52a thereof can freely move a sheet stack to either one of the upstream side and downstream side, implementing delicate adjustment of the stapling position.
The center stapling on the staple tray F and folding are executed at independent stations, so that sheets to be dealt with by the next job can be positioned when folding, which consumes a relatively long period of time, is under way. This is expected to remarkably enhance productivity.
A conventional staple. tray can be sufficiently guaranteed for the maximum sheet length, insuring high-quality stapling.
The turning portion with a small radius R implemented by the guides 54 and 55 and discharge roller 56 promotes smooth steering and conveyance of a sheet stack and therefore further saves space.
While a sheet stack is usually conveyed only by the hook 52a, a strong conveying force is necessary for conveying a sheet stack when the turning portion has a small radius R as in the illustrative embodiment. In light of this, in the illustrative embodiment, the discharge roller 56 in rotation plays the role of a guide and exerts a conveying force on a sheet stack. At this instant, resistance to conveyance is reduced because the guide is rotating in the direction of conveyance.
The guides 54 and 55 capable of selectively steering sheets toward the shift tray 202 or the fold tray G are positioned downstream of the staple tray F. Therefore, the illustrative embodiment can meet user's various needs, e.g., it can simply staple or fold sheets at the center and then discharge it. When it is desired to simply staple sheet at the centers the guides 54 and 55 are closed, as shown in
An alternative embodiment of the illustrative embodiment will be described with reference to
As shown
A guide plate HP sensor 315 senses the interrupter portion 61c of the cam 61 to thereby determine the home position of the cam 61. The stop position of the cam 61 is controlled by using the home position as a reference by counting the drive pulses of the steer motor 161. The amount of opening of the guide plate 54 is determined on the basis of the stop position of the cam 61, i.e., drive pulses input to the steer motor 161. The distance between the discharge roller 56 and the press roller 57 can be freely set in accordance with the amount of opening set. This control will be described more specifically later.
In the condition shown in
The press roller 57 spaced from the discharge roller 56, as shown in
While the illustrative embodiment drives each of the guide plate 54 and movable plate 55 with a particular motor, a cam, link or similar drive transmission mechanism may also be assigned to the movable guide 55 to allow the guides 54 and 55 to share a single motor, if desired.
The center staple mode of the illustrative embodiment differs from the center staple mode of the previous embodiment described with reference to
Control over the steering mechanism and the movement of the belt 52 unique to the illustrative embodiment will be described hereinafter.
If the answer of the step S801 is NO, meaning that the movable guide HP sensor 337 is in an OFF state, then the CPU 360 rotates the movable guide motor 171 clockwise (opposite to the direction of arrow in
The stapling operation and folding operation effected in the center staple mode available with the illustrative embodiment will be described hereinafter. In this mode, the movable guide 55 is angularly moved to steer a sheet stack to the downstream path while the guide plate 54 is closed by a preselected amount to cause the press roller 57 to adjoin the discharge roller 56 at a small distance, as stated earlier with reference to FIG. 25. In the illustrative embodiment, the small distance is variable stepwise in accordance with the number of sheets and smaller than the thickness of a sheet stack. For example, as shown in
Subsequently, a stapled sheet stack starts being moved to the downstream side. As soon as the leading edge of the sheet stack moves away from the nip between the press roller 57 and the discharge roller 55, the CPU 360 further closes the guide plate 54 until the press roller 57 contacts the discharge roller 56. This closing timing is controlled on the basis of the drive pulses of the discharge motor 157 preselected on a sheet size basis, so that the pass distance is identical throughout all the sheet sizes.
For example, assume that the distance by which the belt 52 with the hook 52a moves from the HP sensor 311 to the roller pair 56 and 57 is L1, that the preselected pass distance is 5 mm, and that the distance by which the hook 52a moves from the HP sensor 311 to the trailing edge of a sheet being stacked is Lh. Then, the operation timing is determined by the distance Ln by which the hook 52a has moved from the HP sensor 311 and controlled in terms of the number of pulses. Assuming that the sheet length is Lp, then the distance Ln is produced by:
Ln=L1−Lh−Lp+5 mm
A particular number of pulses are assigned to each sheet size. As shown in
While the illustrative embodiment executes control based on the output of the HP sensor 311, sensing means responsive to the leading edge of a sheet stack may be located in the vicinity of the roller pair 56 and 57. In such a case, the control can be executed without resorting to size information output from the image forming apparatus.
Another alternative embodiment of the present invention will be described hereinafter. This embodiment is also similar to the embodiment described first except for the following.
Reference will be made to
On determining the position of the belt 52 in response to the output of the belt HP sensor 311, the CPU 360 moves the belt 52 to the stand-by position via the discharge motor 157 (step S1103). Also, on determining the positions of the jogger fences 53 in response to the output of the jogger fence HP sensor, the CPU 360 moves the jogger fences 53 to the stand-by positions. Further, the CPU 360 moves the guide plate 54 and movable guide 55 to their home positions where they steer a sheet stack toward the path C (step S1104).
The inlet sensor 301 turns on and then turns off (YES, steps S1105 and S1106), and the staple discharge sensor 305 turns on and then turns off (YES, step S1107 and S1008), meaning that a sheet is present on the staple tray F. Then, the CPU 360 energizes the knock solenoid 170 to cause the knock roller 12 to contact the sheet and force it toward the rear fence 51 for thereby positioning the trailing edge of the sheet (step S1109). Subsequently, the CPU 360 moves the jogger fences 53 inward by a preselected amount via the jogger motor 158 so as to position the sheet in the direction of width and then returns the jogger fences 53 to the stand-by positions (step S1110). The steps S1105 through S1110 are repeated for every sheet.
When the last sheet of a copy arrives at the staple tray F (YES, step S1111), the CPU 360 moves the jogger fences 53 inward by a preselected amount to thereby prevent the edges of the sheets from being shifted (step S1112). This condition is shown in FIG. 23. The CPU 360 then further moves the belt 52 by a preselected amount (step S1113) until the stapling position of the sheet stack coincides with the stapling position of the center staplers S2. Subsequently, the CPU 360 turns on the motor assigned to the center staplers S2 to thereby staple the sheet stack at the center (step S1114). This condition is shown in
As shown in
When the leading edge of the sheet stack arrives at the stack arrival sensor 321 (YES, step 1120) and is then conveyed by a preselected distance, the CPU 360 causes the upper and lower roller pairs 71 and 72 to stop rotating (step S1121). When the belt HP sensor 311 turns on (YES, step S1122), the CPU 360 causes the guide plate 54 and movable guide 55 to move to their home positions for conveying the sheet stack toward the path C (step S1123). The CPU 360 then causes the belt 52 to move until the hook 52a reaches the stand-by position (step S1124). This condition is shown in FIG. 26. Subsequently, the CPU 360 releases the rollers of the lower roller pair 71 from each other (step S1125), as shown in FIG. 27. Thereafter, the CPU 360 causes the fold plate 74 to start folding the sheet stack (step S1126), as shown in
When the pass sensor 323 turns on (YES, step S1128) and then turns off (YES, step S1129), meaning that the trailing edge of the sheet stack has moved away from the sensor 323, the CPU 360 causes the rollers of the lower roller pair 72 to contact each other (step S1130) and causes the fold plate 72 to move to its home position (step S1131).
Subsequently, when the lower outlet sensor 324 turns on (YES, step S1132) and then turns off (YES, step S1133), meaning that the trailing edge of the sheet stack has moved away from the sensor 324, the CPU 360 causes the fold roller pairs 81 and 82 and lower outlet roller pair 83 to stop rotating (step S1134) and causes the jogger fences 53 to move to the stand-by positions (step S1135). The CPU 360 then determines whether or not the sheet stack is the last copy of a job (step S1136). If the answer of the step S1136 is NO, then the procedure returns to the step S1105. If the answer of the step S1136 is YES, then the CPU 130 causes the hook 52a and jogger fences 53 to move to the respective home positions (steps S1137 and S1138), causes the inlet roller pair 1, roller pairs 2, 7, 9 and 11, staple discharge roller pair 11 and knock roller 12 to stop rotating (step S1139), and switches the path selectors 15 and 16 (step S1140). As a result, all the structural parts are returned to their initial positions.
The stapling operation and folding operation to be effected in the fold mode will be described in more detail hereinafter. A sheet conveyed from the path A to the path D via the path selectors 15 and 16 is conveyed to the staple tray F by the staple discharge roller pair 11. After the consecutive sheets have been positioned on the staple tray F in the same manner as in the staple mode (see FIG. 23), the sheet stack is conveyed to the downstream side by the preselected size-by-size distance by the hook 52a and then stapled at the center by the center staplers S2. The stapled sheet stack is conveyed by the hook 52a at the velocity V1 to the position past of the nip between the discharge roller 56 and the press roller 57, but short of the guide surface of the guide plate 54, by the size-by-size distance, as shown in FIG. 41 and then brought to a stop. This distance is controlled on the basis of the drive pulses input to the discharge motor 157.
Subsequently, as shown in
The discharge roller 56 is mounted on the drive shaft 65 associated with the belt 52 and therefore driven in synchronism with the belt 52. Subsequently, as shown in
As shown in
As shown in
A jam is likely to occur during the center staple mode stated above.
Further, the leading edge of a cover PBS on the top of a sheet stack PB is apt to be caught by the press roller, as shown in
More specifically, as shown in
If the answer of the step S1203 is NO, then the CPU 360 turns on the steer motor 161 (step S1204) to return the guide plate 54 and movable guide plate 55 to the home positions (step S1205), displays a jam message (step S1206), and then ends the processing.
When a jam occurs during the fold mode operation, the CPU 360 executes the processing shown in
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.
| Number | Date | Country | Kind |
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| 2001-290600 | Sep 2001 | JP | national |
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| 2002-192536 | Jul 2002 | JP | national |
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