Patent Publication Number: US-7222843-B2

Title: Sheet post-process apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   This application claims priority of Japanese Patent Application No. 2004-285307, filed on Sep. 29, 2004 and Japanese Patent Application No. 2004-366450, filed on Dec. 17, 2004. Contents of these Japanese Paten Applications are cited here, and incorporated with this application. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a sheet post-process apparatus or the like which conducts a post process of a sheet, such as a sheet of paper, etc., to be discharged from an image forming apparatus, such as a composite apparatus of a copying machine, a printer, a multi function peripheral (MFP), and so on. 
   2. Description of the Related Art 
   A post-process apparatus (finisher) which conducts a process (staple process) for bundling and fixing a plurality of sheets printed by the MFP, is known. The finisher sequentially conveys the sheets fed from the MFP to a process tray, binds the sheets by a stapler, and delivers the stapled sheets to a delivery tray. 
   Since a binding process by the stapler exists in this post process of the finisher, it needs a delaying mechanism for absorbing a process speed in the MFP. Therefore, a technology for lengthening a conveying path is known (refer to Japanese Patent Publication No. 6-99070). For this reason, it has been difficult to sufficiently reduce the size of the apparatus. 
   Furthermore, an apparatus for delivering a sheet to an accumulation tray is known as disclosed in Japanese Patent Application Laid-Open Publication No. 10-279160, but the apparatus is not sufficient. 
   BRIEF SUMMARY OF THE INVENTION 
   An object of the present invention is to provide a sheet post-process apparatus in which a distance from a sheet delivery unit to a process mechanism for post-processing of an image forming apparatus is shortened and a size is reduced. Another object of the present invention is to provide a sheet post-process apparatus having a structure for preventing a sheet from being sandwiched between a standby tray and a lateral matching plate and further raising matching properties in a lateral direction. 
   According to an aspect of the present invention, there is provided a sheet post-process apparatus comprising: a standby tray for putting a sheet delivered from an image forming apparatus on standby; a process tray arranged under the standby tray for stacking the sheet dropped from the standby tray or the sheet delivered from the image forming apparatus not through the standby tray; a matching mechanism for matching a lateral direction of the sheet stacked on the process tray by a lateral matching plate to form a sheet bundle; a post-process mechanism for post-processing the sheet bundle matched by the matching mechanism; and a delivery tray for delivering the sheet bundle post-processed by the post-process mechanism, in which the process tray and the standby tray are arranged so as to make a height of an upper end of the lateral matching plate of the process tray higher than a height of a lower end of the standby tray. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a sheet post-process apparatus according to an embodiment of the present invention; 
       FIG. 2  is a top view of the sheet post-process apparatus according to the embodiment of the present invention; 
       FIG. 3  is a view for explaining an operation of a standby tray in the sheet post-process apparatus according to the embodiment of the present invention; 
       FIG. 4  is a view for explaining longitudinal matching and a sheet bundle conveying mechanism in the sheet post-process apparatus according to the embodiment of the present invention; 
       FIG. 5  is a view for explaining a lateral matching mechanism in the sheet post-process apparatus according to the embodiment of the present invention; 
       FIG. 6  is a view for explaining an operation of a stapler in the sheet post-process apparatus according to the embodiment of the present invention; 
       FIGS. 7A to 7D  are views for explaining the relationship between a standby tray and a lateral matching plate in the sheet post-process apparatus according to the embodiment of the present invention; 
       FIG. 8  is a view for explaining a flow of a first sheet between an inlet roller and a sheet feed roller in the sheet post-process apparatus according to the embodiment of the present invention; 
       FIG. 9  is a view for explaining the flow of the first sheet between the sheet feed roller and the standby tray in the sheet post-process apparatus according to the embodiment of the present invention; 
       FIG. 10  is a view for explaining a flow of a second sheet between the sheet feed roller and the standby tray in the sheet post-process apparatus according to the embodiment of the present invention; 
       FIG. 11  is a view for explaining an operation of the standby tray roller in the sheet post-process apparatus according to the embodiment of the present invention; 
       FIG. 12  is a view for explaining an operation of the standby tray roller in the sheet post-process apparatus according to the embodiment of the present invention; 
       FIG. 13  is a view for explaining an operation of an active drop in the sheet post-process apparatus according to the embodiment of the present invention; 
       FIG. 14  is a view for explaining a flow of a third sheet between the sheet feed roller and the standby tray in the sheet post-process apparatus according to the embodiment of the present invention; 
       FIG. 15  is a view for explaining an operation of a stapler in the sheet post-process apparatus according to the embodiment of the present invention; 
       FIG. 16  is a view for explaining a flow of a sheet bundle between a process tray and a sheet delivery tray in the sheet post-process apparatus according to the embodiment of the present invention; 
       FIG. 17  is a view for explaining a flow of a direct sheet delivery of a sheet from a standby tray to the sheet delivery tray in the sheet post-process apparatus according to the embodiment of the present invention; and 
       FIG. 18  is a view for explaining an operation of a position change of a sheet delivery tray in the sheet post-process apparatus according to the embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Now, preferred embodiments of the present invention applied to an MFP will be described in greater detail by referring to the accompanying drawings. 
     FIG. 1  is a perspective view of a post-process apparatus according to an embodiment of the present invention, and  FIG. 2  is a top view of this post-process apparatus. The post-process apparatus  7  fundamentally comprises a standby tray  10 , a process tray  12 , a stapler  14 , a first sheet delivery tray  16 , and a second sheet delivery tray  18 . 
   A sheet  20  fed from the MFP is received by a pair of inlet rollers  22 , supplied to a pair of sheet feed rollers  24 , and sent from the sheet feed rollers  24  to the standby tray  10  (in a conveying direction X). The inlet rollers  22  are driven by an inlet roller motor  26 . The inlet rollers  22  include upper inlet rollers  22   a  and lower inlet rollers  22   b . The sheet feed rollers  24  include an upper sheet feed roller  24   a  and a lower sheet feed roller  24   b.    
   The standby tray  10  includes, as shown in  FIG. 2 , a pair of standby tray components  10   a ,  10   b  which can move laterally, and receives the sheet in the state that the standby tray components  10   a  and  10   b  are closed. In order to match the sheet in this state, standby tray rollers  28  are provided. 
   The standby tray rollers  28  are vertically movable, and are controlled by a standby tray roller drive source  30 . The standby tray rollers  28  are rotated by a standby tray roller motor  32 . 
   When a predetermined number of sheets, for example, two sheets are accumulated in the standby tray  10 , as shown in  FIG. 3 , the standby tray components  10   a  and  10   b  are opened laterally in a direction perpendicular to the sheet conveying direction X by the standby tray motor  34 , and the sheet  20  is dropped by its own weight in the process tray  12 . This operation is called an active drop. 
   A paper path is provided to guide the sheet fed from the MFP to the standby tray  10  and the process tray  12 . This paper path is composed of a paper path ceiling  36  as shown in  FIG. 2 . 
   Matching processes in a longitudinal direction (sheet conveying direction) and a lateral direction are performed to the sheet sent to the process tray  12 . In the longitudinal matching, as shown in  FIG. 4 , sheets are aligned with a stopper  45  as a reference by a longitudinal matching upper roller  38   a  driven by a longitudinal matching upper roller motor  40  and a longitudinal matching lower roller  38   b  driven by a longitudinal matching lower roller motor  42 . 
   Incidentally, when the sheet is fed to the process tray  12 , the longitudinal matching upper roller  38   a  becomes a state that the upper roller  38   a  is opened so as not to come into contact with the longitudinal matching lower roller  38   b  by the longitudinal matching upper roller motor  40 . A paddle  44  is provided to supplement this matching, and is driven by a paddle motor  46 . 
   On the other hand, the lateral matching is performed by moving of the first and second lateral matching plates  47   a ,  47   b  to an arrow v by a lateral matching mechanism  47  and a lateral matching motor  48 , as shown in  FIG. 5 . 
   When a predetermined number of sheets are matched and stored in the process tray  12 , as shown in  FIG. 6 , the staple process is conducted by a stapler  14 . The stapler  14  is moved to an arrow u and positioned by a staple driver  49  to control the staple process. 
   The staple processed sheet bundles are sent to first and second sheet delivery trays  16  and  18  shown in  FIG. 8  by the conveying mechanism  50  shown in  FIG. 4 . The first and second sheet delivery trays  16  and  18  are selected by vertically moving these sheet delivery trays by a sheet delivery tray driver  52 . 
   As shown in  FIG. 3 , a step A is provided between a lower surface  64  of the standby tray  10  and a contact surface  66  of the sheet feed roller  24   a  and the sheet feed roller  24   b . If there is no step A, a lower curled sheet supplied to the standby tray  10  blocks the sheet feed roller  24   b , a jam or irregular stacking order of sheets occurs so that the sheet might drop in the process tray  12 . This step A is provided to prevent such an inconvenience. 
   Incidentally, in this embodiment of the present invention, the relationship between a height of upper ends of the first and second lateral matching plates  47   a ,  47   b  for constituting the lateral matching mechanism  47  shown in  FIG. 5  and a height of a lower end of the standby tray  10  is set to a predetermined relation. 
   More particularly, the embodiment shown in  FIGS. 7A and 7B  has a structure that height Yh of the upper ends of the first and second lateral matching plates  47   a  and  47   b  is the same as a height Tb of the lower end of the standby tray. That is, in this embodiment, the upper ends of the lateral matching plates  47   a  and  47   b  come into contact with the lower end of the standby tray  10 . 
   On the other hand, in the embodiment shown in  FIGS. 7C and 7D , the height Yh of the upper ends of first and second lateral matching plates  47   a ′ and  47   b ′ is higher than the height Tb of the lower end of the standby tray  10 . The standby tray  10 ′ of this case becomes a comb-like teeth state in a structure that the comb-like teeth are engaged with comb-like teeth of the upper ends of the lateral matching plates  47   a ′ and  47   b ′. Thus, an effect of suppressing a sheet jam is further provided. 
   It is difficult to constitute the standby tray and the lateral matching plate of one member, and a conventional apparatus has a gap between the lower end of the standby tray and the upper end of the lateral matching plate. Therefore, the sheet becomes a jam state due to rise or contact of the sheet on or with this gap, and the matching properties are not proper. 
   In the embodiment shown in  FIGS. 7A and 7B , or the embodiment shown in  FIGS. 7C and 7D , the height Yh of the upper end of the lateral matching plate is the same as or higher than the height Tb of the lower end of the standby tray. Therefore, the sheet may not be sandwiched between the standby tray and the lateral matching plate as in the conventional, but finally matching properties of the sheets are raised, and a jam state of sheet can be suppressed. 
   Then, an operation of the post-process apparatus according to the present invention will be described with reference to  FIG. 8  to  FIG. 18 . As shown in  FIG. 8 , the sheet  20  fed from the MFP is sent to the sheet feed rollers  24  as shown by an arrow via the inlet roller  22 . 
   Then, as shown in  FIG. 9 , a first sheet is stored in the standby tray  10  through the sheet feed rollers  24 . At this time, the standby tray roller  28  is lowered as shown by an arrow to match the position of the sheet  20  supplied to the standby tray  10  to a rear end (upstream side)  60  of the standby tray  10 . Then, as shown in FIG.  10 , the standby tray roller  28  is raised to prepare receiving of a second sheet  20   a.    
   When the preparation is completed, as shown in  FIG. 11 , the second sheet  20   a  is sent to the standby tray  10 , the standby tray roller  28  is lowered, and the position of the sheet is aligned to the rear end  60  of the standby tray  10 . Thus, a sheet bundle  20   b  having two sheets  20 ,  20   a  is formed on the standby tray  10 . 
   Then, as shown in  FIG. 12 , the standby tray roller  28  is raised, as further shown in  FIG. 3 , the standby tray components  10   a ,  10   b  are opened, the active drop is performed as shown in  FIG. 13 , and the sheet bundle  20   b  is sent to the process tray  12 . 
   Thereafter, the third and subsequent sheets  20   c  are sent directly from the sheet feed roller  24  to the process tray  12  not through the standby tray  10  as shown in  FIG. 14 , and accumulated on the second sheet bundle  20   b  to form the sheet bundle  21  of a predetermined number of sheets. Then, the longitudinal matching mechanism  38  and the lateral matching mechanism  47  operate to perform the sheet matching of longitudinal and lateral directions. 
   In this case, as shown in  FIG. 14 , the rear end  60  of the standby tray  10  and the rear end  62  of the process tray  62  are spaced at a distance L in the lateral direction so that the rear end of the standby tray  10  is located at a downstream side from the rear end (upstream side)  62  of the process tray  12 . When thus constituted, dropping of the sheet bundle  20   b  from the standby tray  10  to the process tray  12  is facilitated, and the matching operation of the longitudinal matching mechanism  38  and the lateral matching mechanism  47  can be facilitated. As a result, occurrence of a jam or the like can be prevented. 
   Desirably, arrangement of he standby tray  10  and the process tray  12  are obliquely inclined. That is, the rear ends  60  and  62  are disposed at the lowest position, and the sheets  20  and the sheet bundle  21  can be matched to the rear ends  60  and  62  by the own weights of the sheet  20  and the sheet bundle  21 . 
   Then, as shown in  FIG. 15 , the sheet bundle  21  is staple processed by the stapler  14 . As shown in  FIG. 16 , the sheet bundle  21  is sent to the sheet delivery tray  16  by the conveying mechanism  50 , and thereby the post-process is completed. 
   Note that, when the post-process is not required, as shown in  FIG. 17  and  FIG. 18 , the sheet is delivered directly from the standby tray  10  to the sheet delivery tray  16  without intermediary of the process tray  12 . As shown in  FIG. 17 , the sheet fed from the MFP is sent to the sheet delivery tray  16  through the inlet roller  22 , the sheet supply roller  24  and the standby tray  10 . The standby tray roller  28  is lowered to convey the sheet  20 . The sheet delivery tray  16  is slightly raised, as shown in  FIG. 18 , by the sheet delivery tray driver  52 , and receives the sheet fed from the standby tray  10 . 
   In this embodiment, the post-process of the sheet made of paper has been described. However, the matter post-processed according to the present invention is not limited only to the paper, but may be an OHP or the other, a sheet-like recording medium, which is here called a sheet. 
   The post-process in the present invention is, for example, a staple process for bundling a plurality of printed sheets and binding the sheets. However, the present invention is not limited to this. 
   In the description of the above embodiment, the case that the present invention is applied to the MFP has been described. However, the present invention is not limited to this, but can be applied to a general post-process of the sheet printed by the image forming apparatus. 
   In the foregoing description, an embodiment of the present invention has been described. However, the present invention is not limited to the above-mentioned embodiment, but the constituting elements can be altered in a range that the same technical thought as the present invention, and these elements may be included in the present invention.