Abstract:
An image forming device having a printing unit, an intermediate tray, and a stapler fixed at a predetermined position, which stacks printed paper printed by the printing unit in the intermediate tray after either a face-down process or a face-up process when performing a normal operation and staples the printed paper when a number of sheets thereof reaches a predetermined number, the image forming device includes: an input unit allowing input of a choice of the face-down process or the face-up process and a choice of one-side printing or two-side printing; and a control unit controlling the image forming device so as to stack the printed paper in the intermediate tray after the printing unit performs two-side printing if a process selected using the input unit is different from one which is performed in the normal operation.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to an image forming device which can staple printed documents, a method for printing and a program recording medium.  
         [0003]     2. Description of Related Art  
         [0004]      FIG. 6  is a schematic diagram showing a conventional image forming device having a stapler, a paper feeding passage thereof, and printed documents being stapled.  
         [0005]     In  FIG. 6 , when printing on one side, paper  1  in a paper feeding tray  2  is fed one sheet at a time as symbol ( 1 ) shows. Then an image is printed on the paper  1  by an image forming portion  3  constituted by a photosensitive drum or the like as shown by symbol ( 2 ). The printed paper  1  is stacked in an intermediate tray  4 , pushed to the front in  FIG. 6  for aligning its end when a page number reaches a desired number, and stapled by a stapler  5 . Finally, a stapled sheaf of paper  6  is discharged in a catch tray  7  as shown by symbol ( 3 ).  
         [0006]     In this device, printing is performed from the first page of the document in order and the pages stacked in the intermediate tray  4  face-down (hereinbelow, simply referred to as the “face-down process”). Thus the sheaves of paper  6  stapled into a desired number of sheets are stacked in the catch tray  7 . The sheaf of paper  6  is stapled at a staple point  8  located at the upper left of the sheaf with respect to the image printed thereon.  
         [0007]     When printing on both sides, an image of an odd-numbered page is printed on one side of the paper  1 . Then the paper  1  is reversed and an image of an even-numbered page is printed on the other side of the paper  1 . The paper both sides of which are printed onto is fed to the intermediate tray  4  and stacked therein face-down.  
         [0008]     An image forming device which staples using post-processing equipment has been proposed (see, for example, Japanese Unexamined Patent Application, Publication No. 2000-44109). An image forming device which can move its staple point when printing on one side, by stapling after reversing the paper when it is placed in landscape orientation has been proposed (see, for example, Japanese Unexamined Patent Application, Publication No. 2003-337508). In addition, an image forming device in which it is made possible for assembly and fixing of jams to be performed easily by having a first unit including an intermediate tray and a second unit with a carrying and branching function has also been proposed (see, for example, Japanese Unexamined Patent Application, Publication No. 2001-235916).  
         [0009]     In low-cost image forming devices which can perform stapling like the one shown in  FIG. 6 , only one stapler  5  is provided and it is fixed at a predetermined position. In a case where the stapler  5  is fixed, the staple point  8  on the sheaf of paper  6  is fixed at the upper left thereof with respect to the printed image as shown in  FIG. 6 . Therefore, the sheaf is stapled at a position which the user does not desire for certain image orientations (portrait or landscape) and feeding directions (short-edge feed or long-edge feed, which will be described later).  
         [0010]     For example, in  FIG. 7 , the staple point  8  is set at the upper left of the paper with respect to the printed image when the image is fed lengthwise (portrait-long edge feed). When the image is fed upside down, the staple point  8  is set at the bottom right of the paper with respect to the printed image as shown in pattern A. In cases where the image is fed at a 90° rotation with respect to the original direction such as in pattern B (portrait-short edge feed) or pattern C (landscape-long edge feed), the staple point  8  is set at the upper right or bottom left of the paper with respect to the printed image. The staple point  8  is set at the upper left or bottom right of the paper with respect to the printed image in pattern D (landscape-short edge feed).  
         [0011]     That is, in the cases shown in  FIG. 7 , the staple point  8  is always fixed on one diagonal line on the paper. In addition, the staple point  8  is set at the upper right or bottom left when the image is fed in a direction perpendicular to the lines of text. Most users generally desire the staple point  8  to be at the upper left of the sheaf of the paper  6  with respect to the image printed thereon. Accordingly, there is a problem in that a document cannot be stapled at a desired position in image feeding conditions like pattern B or pattern C shown in  FIG. 7 . Rotating the paper so that it is at a 90° rotation is a possible solution to this problem. However, this problem cannot be avoided in a case where paper of a large size such as A3 paper is used because such large sized paper cannot be turned.  
       SUMMARY OF THE INVENTION  
       [0012]     An object of the present invention is to control an image forming device so as to set a staple point at the upper left of printed paper with respect to a printed image even when paper is fed as in pattern B or in pattern C in  FIG. 7 .  
         [0013]     A first aspect of the present invention is an image forming device having a printing unit, an intermediate tray, and a stapler fixed at a predetermined position, which stacks printed paper printed by the printing unit in the intermediate tray after either a face-down process or a face-up process (a process in which the printed paper is stacked in the intermediate tray face-up) when performing a normal operation and staples the printed paper when a number of sheets thereof reaches a predetermined number, the image forming device comprising: an input unit adapted to allow input of a choice of the face-down process or the face-up process and a choice of one-side printing or two-side printing; and a control unit which controls the image forming device so as to stack the printed paper in the intermediate tray after the printing unit performs two-side printing if a process selected using the input unit is different from one which is performed in the normal operation.  
         [0014]     The control unit may control the printing unit so as to perform two-side printing, printing blank data on one side of the paper when one-side printing is selected using the input unit.  
         [0015]     A second aspect of the present invention is a recording medium on which is recorded a program applicable to an image forming device having a printing unit, an intermediate tray, and a stapler fixed at a predetermined position, which stacks printed paper printed by the printing unit in the intermediate tray after either a face-down process or face-up process when performing a normal operation and staples the printed paper when a number of sheets thereof reaches a predetermined number, wherein the program comprises: a first step of receiving input of a choice of the face-down process or the face-up process and a choice of one-side printing or two-side printing; a second step of controlling the printing unit so as to perform two-side printing if a process chosen in the first step is different from one which is performed in the normal operation; and a third step of controlling the image forming device so as to stack the printed paper in the intermediate tray.  
         [0016]     In the second step, the printing unit may be controlled so as to perform two-side printing, printing blank data on one side of the paper when one-side printing is selected in the first step.  
         [0017]     A third aspect of the present invention is a method for image printing applicable to an image forming device having a printing unit, an intermediate tray, and a stapler fixed at a predetermined position, which stacks printed paper printed by the printing unit in the intermediate tray after either a face-down process or a face-up process when performing a normal operation and staples the printed paper when a number of sheets thereof reaches a predetermined number, the method for image printing comprising: a first step of receiving input of a choice of the face-down process or the face-up process and a choice of one-side printing or two-side printing; a second step of controlling the printing unit so as to perform two-side printing if a process chosen in the first step is different from one which is performed in the normal operation; and a third step of controlling the image forming device so as to stack the printed paper in the intermediate tray.  
         [0018]     In the second step, the printing unit may be controlled so as to perform two-side printing, printing blank data on one side of the paper when one-side printing is selected in the first step. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]      FIG. 1  is a schematic diagram showing a paper feeding passage of an image forming device according to an embodiment of the present invention and a sheaf of printed paper.  
         [0020]      FIG. 2  is a diagram showing a change of printing order of image data when performing one-side printing.  
         [0021]      FIG. 3  is a flowchart showing operation in one-side printing.  
         [0022]      FIG. 4  is a diagram showing a change of printing order of image data when performing two-side printing.  
         [0023]      FIG. 5  is a block diagram showing an image forming device according to an embodiment of the present invention.  
         [0024]      FIG. 6  is a schematic diagram showing a paper feeding passage of a conventional image forming device and a sheaf of printed paper.  
         [0025]      FIG. 7  is a diagram showing staple points in several patterns of different feeding directions and shapes of images. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0026]     An embodiment of the present invention is described below with reference to the drawings.  FIG. 1  is a schematic diagram showing a paper feeding passage of an image forming device with a stapler according to an embodiment of the present invention and a sheaf  6  of printed paper. In  FIG. 1 , components identical to those in  FIG. 6  are referred to using the same reference numerals and redundant descriptions are omitted.  FIG. 1  shows a case of landscape-long edge feed, which is referred to as pattern C in  FIG. 7 .  
         [0027]     This embodiment performs printing from the last page of images and performs a face-up process in which printed paper is stacked in the intermediate tray  4  face-up in order to set the staple point  8  at the upper left of the sheaf  6  with respect to the printed image. When performing the face-up process, the paper  1  on which the image is printed by the image forming portion  3  is fed to the intermediate tray  4  after being reversed at a switchback unit  9  which is used in conventional image forming devices in order to perform two-side printing. When the paper  1  stacked in the intermediate tray  4  reaches a predetermined number of sheets, the sheaf  6  is stapled by the stapler  5  and discharged to the catch tray  7 . Thus the sheaves  6  of the predetermined number of sheets are stapled and stacked on the catch tray  7  face up. In this case, the staple point  8  is always located at the upper left of the sheaf  6  with respect to the printed image, as shown in  FIG. 1 .  FIG. 2  shows operation of printing five-page image data with one-side printing and landscape-long edge feed.  FIG. 3  is a flowchart showing operation in the situation shown in  FIG. 2 .  
         [0028]     In  FIG. 3 , a user sets “face-up staple mode” to set the staple point  8  at the upper left of the sheaf  6  with respect to the printed image when performing one-side printing and landscape-long edge feed (pattern C in  FIG. 7 ) is performed (step S 1 ). If the size, type, and feeding tray of the paper render copying impossible (YES in step S 2 ), the face-up staple mode is determined to be unavailable. The image forming device displays a message indicating the face-up staple mode cannot be used (step S 3 ) and terminates the process.  
         [0029]     If copying is possible under the conditions set, the printing order of the image data to be printed is changed as shown in  FIG. 2  (step S 4 ). Specifically, the printing of the image data is performed from page  5 , then page  4 , page  3 , page  2 , and page  1  in order. Dummy blank datum D is inserted after each page of the image data. Then, two-side printing is set as the type of printing to perform (step S 5 ) although the user has selected one-side printing in this case.  
         [0030]     Next, the paper  1  is fed from the feeding tray  2  as shown by symbol ( 1   a ) in  FIG. 1  and printing is started from the last page (here, page  5 ) (step S 6 ). Five sheets of paper printed by the image forming portion  3  are reversed at the switchback unit  9  as shown by symbol ( 2   a ) in  FIG. 1 , and are fed back through another feeding passage as shown by symbol ( 3   a ). Then the paper passes through the image forming portion  3  again and blank datum is printed on the other side thereof (step S 8 ). That is, the paper just passes through the image forming portion  3  without being printed on.  
         [0031]     The printed paper is fed to the intermediate tray  4  face-up (step S 9 ). Then it is determined whether a number of sheets of the printed paper has reached a predetermined number (e.g., five sheets) (step S 10 ). If it is determined that the number of sheets of the printed paper has not reached the predetermined number, the next page of the image data is printed (step S 11 ).  
         [0032]     Steps S 7  to S 11  are repeated until the number of sheets of the printed paper reaches the predetermined number. When the last printed page (in this case, page  1 ) of the predetermined number has been stacked in the intermediate tray  4 , the sheaf  6  of the printed paper is stapled by the stapler  5  (step S 12 ), and is stacked on the catch tray  7  face-up (step S 13 ). Through these processes, the five-sheet sheaf  6  of paper, being stacked in order of page  1 , page  2 , page  3 , page  4 , and page  5  and with the staple point  8  set at the upper left of the paper with respect to the printed image, can be obtained.  
         [0033]      FIG. 4  shows each page in an operation of printing five-page image data with two-side printing and landscape-long edge feed.  
         [0034]     In the operation shown in  FIG. 4 , the paper is reversed and stacked in the intermediate tray  4  face-up after the last page (in this case, page  5 ) has been printed. Then page  3  is printed on the next sheet of paper. The next sheet of paper is reversed and page  4  is printed on the other side. The next sheet of paper is stacked in the intermediate tray  4 , with page  3  up. Then page  1  is printed on the third sheet of paper. The third sheet of paper is reversed and page  2  is printed on the other side. The third sheet of paper is stacked in the intermediate tray  4 , with page  1  up. Through these processes, the three-sheet sheaf  6  of paper, being stacked in order of page  1  (with page  2  printed on the other side), page  3  (with page  4  printed on the other side), and page  5  with the staple point  8  set at the upper left of the paper with respect to the printed image, can be obtained.  
         [0035]     In the operations shown in  FIGS. 2 and 4 , when image data of more than five pages (e.g., 20 pages) are printed and the printed paper is stapled into five-sheet sheaves, printing is performed from page  20 . Thus the printed paper is stapled into five-sheet sheaves  6  and stacked successively.  
         [0036]     As described above, the face-up staple mode of the present embodiment is one in which face-up staple processing is performed by always performing two-side printing even if the user chooses one-side printing, and by starting printing from the last page of the image data to be printed. On the other hand, the conventional image forming device shown in  FIG. 6  starts printing from the first page of image data to be printed and performs stapling after a face-down process. Therefore, the present embodiment can be realized by the aforementioned conventional image forming device without additional components, if it is controlled to always perform two-side printing even if the user chooses one-side printing, and to start printing from the last page of image data to be printed while performing a face-down process. The present embodiment can be applied to conventional image forming devices with few changes because the operations required of the conventional image forming device are substantially identical to the operations performed when two-side printing is carried out. Although an example is given above for when the present embodiment is applied to a conventional image forming device which performs a face-down process in normal operation, the present embodiment can be also applied to image forming devices which perform a face-up process in normal operation. In this case, the image forming device should be controlled to always perform two-side printing even if the user chooses one-side printing, and to start printing from the first page of the image data to be printed.  
         [0037]      FIG. 5  is a block diagram showing an image forming system including an image forming device for the aforementioned printing method.  
         [0038]     A personal computer (PC)  10 , a host computer, has a central processing unit (CPU)  11 , an operation and display unit  12  for operations including selecting the face-up staple mode and display thereof, a printer driver  13 , and an information processing unit  14 . An image forming device  20  has a device CPU  21  which controls the whole image forming device, an image processing unit  22 , a printing unit  23 , and post-processing equipment  24  having a stapler  5 . The printing unit  23  has a printer controller  25 , an engine controller  26 , and a print engine  27 . The post-processing equipment  24  may be removable from the image forming device  20  itself.  
         [0039]     In the system of the aforementioned constitution, the change of printing order of image data to be printed shown in  FIGS. 2 and 4  may be performed by the printer driver  13  in the PC  10 , and the image data may be sent to the printing unit  23  from the last page. In this case, when the face-up staple mode is selected using the PC  10  and a command to use face-up staple mode is received by the device CPU  21  of the image forming device  20 , the device CPU  21  controls the image forming device  20  so as to perform the face-down process, the same as in a conventional case, and to change the printing order of the image data, always performing two-side printing, when conditions allow for the face-up staple mode. The face-up staple mode thus can be performed.  
         [0040]     The change of printing order of image data may be performed by the printer controller  25 . In this case, the printing order is changed after all pages of the image data are saved in a memory device in the image forming device  20 . Operation in the face-up staple mode may be performed by the engine controller  26 . In this case, the engine controller  26  can handle the face-down stapling process. Insertion and changing the printing order of the blank data may be performed by a combination of the printer driver  13  and the printer controller  25 , the printer controller  25  only, or the engine controller  26 .  
         [0041]     A program for carrying out a printing method of the present embodiment and a program recording medium on which the program is recorded are described below.  
         [0042]     A program for the device CPU  21  in the computer system of the image forming device  20  according to an embodiment of the present invention to control the image forming device  20  so as to perform the aforementioned operations and the processing shown in the flowchart of  FIG. 3  corresponds to a program according to the present invention.  
         [0043]     A magnetooptical disc, an optical disc, semiconductor memory, or a magnetic recording medium may be used to record the program and these recording media may be in the form of read only memory (ROM), random access memory (RAM), a CD-ROM, a flexible disc, a memory card, or the like. A recording medium which maintains the program for a certain period of time like volatile memory such as a RAM in a computer system used as a server or a client when the program is sent via a network or telecommunication lines such as phone lines is also included among the aforementioned recording media.  
         [0044]     The program may be one sent from a computer system which saves the program in a memory device or the like to another computer system via a transmission medium or by a transmitted wave in the transmission medium. The phrase “transmission medium” means a medium which has a function of transmitting information such as the Internet (a communication network) or telecommunication lines such as phone lines (communication lines). The program may be one for performing a part of the aforementioned functions. The program may be a differential file (differential program) which enables the computer system to perform the aforementioned function in combination with a program recorded on the computer system.  
         [0045]     Accordingly, the program or the recording medium on which the program is recorded may be located in a system or a device different from the system or the device shown in  FIGS. 1 and 5 . In this case as well, identical functions and effects to those of the system or device of the aforementioned embodiment can be obtained when the system or device of the present invention executes the program located in the different system or the different device. Thus the objects of the present invention can be accomplished.  
         [0046]     While preferred embodiments of the invention have been described and illustrated above, it should be understood that these are exemplary of the invention and are not to be considered as limiting. Additions, omissions, substitutions, and other modifications can be made without departing from the spirit or scope of the present invention. Accordingly, the invention is not to be considered as being limited by the foregoing description, and is only limited by the scope of the appended claims.