Patent Application
20110215523
1. Field of the Invention
The present invention relates to a sheet processing apparatus which applies a process such as a binding process to sheets, and an image forming apparatus having the sheet processing apparatus.
2. Description of the Related Art
Conventionally, in a sheet processing apparatus which applies a process such as staple binding to a sheet bundle on which images are formed by an image forming apparatus, there is a problem that throughput decreases when the process is applied. More specifically, a process operation, an operation of discharging from a processing portion a processed sheet bundle, and an operation of enabling the apparatus to receive the first sheet of a subsequent sheet bundle cannot be performed only in a period between sheet bundles upon continuous printing. Hence, between sheet bundles, it is necessary to provide a large interval between sheets by temporarily stopping to form images.
A configuration (U.S. Pat. No. 7,306,214) which makes some of first sheets forming a subsequent sheet bundle temporarily wait to buy some processing time and a configuration (U.S. Pat. No. 7,237,774) which enables a processing portion to receive a subsequent sheet bundle when a processed sheet bundle is discharged, are disclosed to solve this problem.
However, with a configuration disclosed in U.S. Pat. No. 7,306,214, a dedicated conveying path, conveying portion and driving portion which make the first page of a subsequent sheet bundle temporarily wait are required, and this makes apparatuses larger and more costly.
Further, with the configuration disclosed in U.S. Pat. No. 7,237,774, when the first page of a subsequent sheet bundle is conveyed, the discharging lever must be retracted, and, accompanying speeding up of image forming apparatuses, a bundle discharging process is not performed on the right time between sheet bundles, causing the decrease in throughput.
Therefore, the present invention provides a sheet processing apparatus and an image forming apparatus having this sheet processing apparatus which enables a processing portion to receive some of the first sheets of a subsequent sheet bundle during a process operation and a discharging operation, and which can prevent the decrease in throughput while preventing the apparatus from becoming larger size and more costly.
To solve the above problem, typical configurations of the sheet processing apparatus and the image forming apparatus according to the present invention include a conveying portion which conveys a sheet, a first stacking portion on which the sheet conveyed by the conveying portion is stacked, a processing portion which processes sheets stacked on the first stacking portion, a sheet discharging portion which includes a sheet discharging member which presses an upstream end of the sheets, processed by the processing portion, in a sheet conveying direction to discharge the sheets to a second stacking portion, and the sheet discharging portion has a sheet supporting member, movable in the sheet conveying direction, which can support a lower surface of the sheet conveyed by the conveying portion while a sheet stacked on the first stacking portion is processed by the processing portion.
The present invention enables a processing portion to receive some of the first sheets of a subsequent sheet bundle during a process operation and a discharging operation, and can prevent the decrease in throughput while preventing an apparatus from becoming larger and more costly.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
A first embodiment of a sheet processing apparatus and an image forming apparatus according to the present invention will be described with reference to drawings.
As illustrated in
The image forming apparatus body 1 separates and feeds a plurality of sheets S stacked in a sheet cassette 2 one by one by a feed roller 4 and separation conveying roller 5, and conveys the sheets to the image forming process unit 7 along a conveying guide 6.
The image forming process unit 7 is an image forming portion which forms an image (toner image) according to an electrophotographic system. That is, with the image forming process unit 7, a laser scanner 9 irradiates a photosensitive drum 8 of an electrical-charged image bearing member to form an electrostatic latent image, develops an electrostatic latent image as a toner image using toner and transfers a toner image to the sheet S.
The sheet S on which the toner image is transferred from the photosensitive drum 8 is conveyed to a fixing device 10, and is fixed an image thereon by being applied heat and pressure. The sheet S on which an image is fixed is switched between a face-up conveying path 12 and switch-back conveying path 15 by a conveying path changeover member 11.
The sheet conveyed to the switch-back conveying path 15 is conveyed by a switch-back conveying roller 16 until the rear end of the sheet S passes a reverse changeover member 17. Then, the switch-back conveying roller 16 reverses, and therefore, the sheet S is transferred in a state where its rear end is reversed upside down as the front end side. At this time, when the reverse changeover member 17 is switched, the reversed sheet S is conveyed to a face-down conveying path 18.
The face-up conveying path 12 and face-down conveying path 18 join before a discharge roller 19. The sheet S guided to the face-up conveying path 12 and the sheet S having passed from the switch-back conveying path 15 to the face-down conveying path 18 are both discharged from the image forming apparatus body 1 by the discharge roller 19.
The image reading portion 20 includes a scanner portion 21 and an automatic document feeding portion (hereinafter “ADF”) 22. The ADF 22 separates and feeds a plurality of sheets of document stacked on a document stack tray 23 one by one by a feeding roller 24, and makes the sheets pass a document reading position 25 where an optical carriage 27 of the scanner portion 21 stops. Further, the ADF 22 is openable rearward about the hinge (not illustrated) in the rear side of the apparatus, and is opened and closed when a document is placed on a platen glass 26.
With the scanner portion 21, the optical carriage 27 scans the document placed on the platen glass 26 in the horizontal direction to read information disclosed in the document, and photoelectrically converts this information by a CCD. Further, when the ADF 22 reads a document, the optical carriage 27 stops at the document reading position 25 and reads information disclosed in the document which is being conveyed.
(Sheet processing apparatus 200)
Next, a sheet processing apparatus 200 will be described.
As illustrated in
The conveying path 201 receives a sheet conveyed by the discharge roller 19 of the image forming apparatus body 1, and guides the sheet S to a pair of conveying rollers 202 of a conveying portion. The intermediate stacking portion 203 of the first stacking portion is provided in a downstream of a sheet conveying direction (arrow X direction) of a pair of conveying rollers 202, and temporarily places the sheets S conveyed from a pair of conveying rollers 202. The stack tray 204 and stacking reference wall 205 are provided in the downstream of the sheet conveying direction of the intermediate stacking portion 203. The stack tray 204 of the second stacking portion allows sheets S to be stacked, and the stacking reference wall 205 of the reference wall hits and aligns the upstream end of the sheets S stacked in the stack tray 204 in the sheet conveying direction. The returning portion 206 served as a shifting portion is provided above the intermediate stacking portion 203, and returns the sheet S placed on the intermediate stacking portion 203 toward the stacking reference wall 205 and performs an aligning process in a sheet conveying direction. The aligning portion 207 is provided in the downstream of the sheet conveying direction of the intermediate stacking portion 203 and above the stack tray 204. The aligning portion 207 supports a part of the lower surface of the sheets S stacked in the intermediate stacking portion 203, presses the end portion of the sheets S in the sheet width direction, and aligns the sheets S in the sheet width direction (arrow Y direction) crossing the sheet conveying direction (arrow X direction). The sheet conveying detection flag 208 is provided in the middle of the conveying path 201, and swings and switches between light blocking and light transmission of a transmission sensor that is not illustrated when the sheet S passes the conveying path 201.
The controlling portion 270 has a CPU, ROM and interface receiving print signals, and controls operations of the returning portion 206, the aligning portion 207 and the lever units 220. The controlling portion 270 controls the lever units 220 such that a subsequent sheet conveyed while a preceding sheet to be processed by the stapler 209 is stacked in the intermediate stacking portion 203 is supported by a sheet supporting member 211. In addition, the controlling portion 270 may be provided within the image forming apparatus body 1.
(Lever unit 220)
The lever unit 220 has a sheet discharging member 210, a sheet supporting member 211, a belt 212, a first pulley 213, a second pulley 214 and a spring 217. The sheet discharging member 210 and the sheet supporting member 211 are provided below the conveying path 201. The belt 212 with no end is stretched in a tensioned state between the first pulley 213 and the second pulley 214 below the sheet discharging member 210. The first pulley 213 is connected to a coaxial gear 215, and the gear 215 is also connected to a motor (driving portion) 216. Consequently, when the motor 216 rotates normally and reversely, the belt 212 rotates normally and reversely. Further, the belt 212 and the sheet supporting member 211 are formed integrally, and, when the belt 212 rotates normally and reversely, the sheet supporting member 211 horizontally moves in the rotating direction of the belt 212. In addition, the moving direction of the sheet supporting member 211 is arranged to be virtually parallel to the surface of the intermediate stacking portion 203 on which sheets are placed. Further, the spring 217 is attached to the sheet discharging member 210 such that a force is applied to the sheet discharging member 210 in the upstream direction of the sheet conveying direction.
The operations of the sheet discharging member 210 and the sheet supporting member 211 will be described with reference to
The sheet discharging member 210 and the sheet supporting member 211 are not restricted in the rotating direction of the belt 212, and respectively move independently. Therefore, as illustrated in
In the second position, the lower surface of the sheet supporting member 211 and the surface of the intermediate stacking portion 203 on which sheets are placed are formed to have an adequate gap. Although the details will be described below, the “adequate gap” refers to a gap which is slightly wider than a maximum value of the thickness of a sheet bundle (maximum sheet bundle thickness) which can be processed by the sheet processing apparatus 200. That is, this gap has an adequate size such that the sheet bundle stacked in the intermediate stacking portion 203 and the sheet supporting member 211 do not interfere, and the apparatus does not become larger because the gap is too large.
When the sheet discharging member 210 and the sheet supporting member 211 are returned to the first position, the motor 216 reversely rotates, the belt 212 rotates in a direction in which the sheet supporting member 211 is moved toward the upstream of the sheet conveying direction, and the sheet supporting member 211 moves to the first position. The sheet discharging member 210 moves to the first position together with the sheet supporting member 211 by means of the force applied by the spring 217.
Further, two lever units 220 are provided in the sheet width direction (arrow Y direction). The first pulley 213 of each of the two lever units 220 is provided coaxially. Similarly, the second pulley 214 of each of the two lever units 220 is provided coaxially. By this means, the two lever units 220 are driven by one motor 216.
Next, operations of the returning portion 206, the aligning portion 207 and the lever units 220 when continuous binding process is performed will be described.
In
Accompanying rotation of the timing belt 256, the aligning portions 207a and 207b move from the retracted position to the sheet receiving position in synchronization. The retracted position refers to the position where sheets are not received outside the sheet width of the sheets conveyed in the sheet width direction. The sheet receiving position refers to the position where sheets can be received inside the sheet width of the sheets conveyed in the sheet width direction.
As illustrated in
As illustrated in
As illustrated in
As illustrated in
By contrast with this, the returning portion 206 served as a shifting portion includes a rotation support axis 206a, arm portion 206b and roller portion 206c. The returning portion 206 is rotated about the rotation support axis 206a by the driving portion that is not illustrated, from a separated position (position illustrated in
As illustrated in
The sheet S is conveyed until the rear end in the sheet conveying direction passes a pair of conveying rollers 202, and is moreover aligned as described above by the aligning portion 207 and the returning portion 206. After the sheet S is aligned, whether an aligning process of a predetermined number of sheets (one bundle) is finished (S7) is determined, and the above aligning process is repeated per sheet if the aligning process is not finished (S4 to S6).
When the aligning process of a predetermined number of sheets is finished, whether there is the next sheet bundle to be processed is decided (S8). If the sheet bundle which must be continuously processed is printed, the sheet S2 of the first page of the subsequent sheet bundle is conveyed into the sheet processing apparatus 200. Before the front end of the subsequent sheet S2 passes the pair of conveying rollers 202, the sheet supporting member 211 moves to the second position as illustrated in
In parallel to the front end of the subsequent sheet S2 passing the pair of conveying rollers 202, the stapler 209 binds the sheet bundle (S11). As illustrated in
After the binding process is finished, the sheet supporting member 211 further moves to the third position as illustrated in
As described above, when the sheet bundle discharging process is finished while a sheet of the subsequent sheet bundle is conveyed, the aligning portion 207 moves again to the sheet receiving position (S15). As described above, the most downstream portion of the sheet supporting member 211 is configured to enter vertically into the aligning portion 207, and therefore, the sheet S2 held by the sheet supporting member 211 is guided into the aligning portion 207.
When the rear end of the subsequent sheet S2 passes the pair of conveying rollers 202 (S16), the sheet discharging member 210 and the sheet supporting member 211 retract to the first position (S17), and the subsequent sheet S2 is aligned in the sheet width direction and the sheet conveying direction. The operation of retracting the sheet discharging member 210 and the sheet supporting member 211 and the aligning process in the width direction may be performed at the same time. The operations of the aligning process, the binding process and the sheet bundle discharging process of the second and subsequent pages of the subsequent sheet bundle are the same as the process of the preceding sheet bundle.
In S18, when there is no next sheet bundle to be processed, the stapler 209 binds the sheet bundle (S18). After the binding process is finished, the sheet supporting member 211 moves to the third position (S19). Accompanying movement of the sheet supporting member 211 to the third position, the sheet discharging member 210 also moves to the downstream of the sheet conveying direction. At this time, the aligning portion 207 moves to the retracted position, and an interval becomes wider than the sheet width (S20). With the bound sheet bundle, the rear end is pressed in the sheet conveying direction by the sheet discharging member 210, and is discharged from the intermediate stacking portion 203 to the stack tray 204 (S21). When all processes are finished, the lever units 220 are retracted to the first position (S22), and the sheet processing apparatus 200 enters the standby state (S1).
According to the present embodiment, as described above, even during the process operation and the discharging operation, it is possible to support the sheet of the subsequent sheet bundle by the sheet support member 211 and prevent the decrease in throughput. Further, a dedicated conveying path, a conveying portion and a driving portion which make sheets of a subsequent bundle temporarily wait are not required, so that it is possible to prevent the apparatus from becoming larger and more costly.
A second embodiment of a sheet processing apparatus and an image forming apparatus according to the present invention will be described with reference to drawings. The overlapping portions from the above description of the first embodiment will be assigned the same reference numerals, and description thereof will not be repeated.
As illustrated in
A sheet is aligned on the sheet supporting surface 321 in the sheet conveying direction by the returning portion 206.
By this means, to align the sheet S2 of the first page of the subsequent sheet bundle in the conveying direction, it is not necessary to retract the sheet supporting member 211 to the first position and stack the sheet S2 on the intermediate stacking portion 203. Further, even if the sheet supporting member 211 is retracted to the first position after the sheet S2 is aligned in the conveying direction, the retracting direction and the returning direction of the sheet supporting surface 321 are the same, and therefore, the retracting operation of the sheet supporting surface 321 does not disturb alignment of sheets.
Further, with the above configuration of the first embodiment, before the operation of aligning the first page of the subsequent sheet bundle is started and after the operation of aligning the last page of the preceding bundle is finished, it is necessary to retract the lever units 220 to the first position as illustrated in S14 of
Next, a third embodiment of a sheet processing apparatus and an image forming apparatus according to the present invention will be described with reference to drawings. The overlapping portions from the above description of the first embodiment will be assigned the same reference numerals, and description thereof will not be repeated.
In
By contrast with this, if the sheet S2 having a smaller size than the sheet size of
With the above configuration, it is possible to provide the effect acquired in the first embodiment for an arbitrary sheet size. Further, by allowing the sheet discharging member 210 to move in the sheet width direction, it is possible to press a well-balanced position of a sheet bundle such that the sheet bundle does not rotate when the sheet bundle is discharged, and discharge the sheet bundle.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2010-048772, filed Mar. 5, 2010, which is hereby incorporated by reference herein in its entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2010-048772 | Mar 2010 | JP | national |
