Abstract:
An image forming apparatus is capable of connecting to a finisher which requires a warm-up process before use. The image forming apparatus comprises an input port which inputs warm-up information from the finisher, and a controller which controls the image forming apparatus to transport a set of sheets to the finisher regardless of the warm-up information. The set of sheets are subjected to a finishing operation carried out only after completing the warm-up process.

Description:
RELATED APPLICATION  
       [0001]     This application is based on Japanese Patent Application No. 2004-154417 filed in Japan on May 25, 2004, the entire content of which is hereby incorporated by reference.  
       BACKGROUND  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to an image forming apparatus to which a post-processing apparatus (finisher) that needs a warm-up process is connected, and to an image forming system in which such an image forming apparatus and a post-processing apparatuses are coupled.  
         [0004]     2. Description of Related Art  
         [0005]     There has been widely used a system which couples an image forming apparatus and a post-processing apparatus, and which processes in the post-processing apparatus a plurality of sheets on which images are formed by the image forming apparatus. Recently, there have been proposed various types of post-processing apparatuses provided with a bookbinding function. The bookbinding function makes a stack of sheets by stacking a plurality of sheets conveyed from the image forming apparatus on a sheet stacking tray and then produces a book by binding the stack of sheets.  
         [0006]     Among post-processing apparatuses, there are some apparatus that need warm-up until a post-processing function becomes usable. For example, a post-processing apparatus that carries out bookbinding by the use of a hot-melt type adhesive is one example of them. Such a post-processing apparatus is provided with a heating member for melting the adhesive. However, it is not possible to carry out bookbinding operations during a warm-up process of heating the heating member up to the melting temperature of the adhesive.  
         [0007]     Conventionally, when using such a post-processing apparatus needing such a worm-up process and an image forming apparatus by connecting them, operations of the image forming apparatus was controlled to start after waiting until the worm-up process has been completed. As a consequence, when using a post-processing apparatus requiring a long warm-up period, the efficiency of the bookbinding operation for the first copy of a book has particularly lowered.  
       SUMMARY  
       [0008]     An object of the present invention is to provide an image forming apparatus that improves the work efficiency when it is used by being connected to a post-processing apparatus needing warm-up, and to provide an image forming system structured by an image forming apparatus and a post-processing apparatus.  
         [0009]     The above purpose is achieved by providing an image forming apparatus configured as follows.  
         [0010]     An image forming apparatus being capable of connecting to a finisher which requires a warm-up process before use, said image forming apparatus comprises an input port which inputs warm-up information from the finisher, and a controller which controls the image forming apparatus to transport a set of sheets to the finisher regardless of the warm-up information, said set of sheets being subjected to a finishing operation carried out only after completing the warm-up process.  
         [0011]     The invention itself, together with further objects and attendant advantages, will best be understood by reference to the following detailed description taken in conjunction with the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]      FIG. 1  is an outline concept drawing of the image forming system.  
         [0013]      FIG. 2  is a schematic diagram showing the peripheral parts near the binding unit.  
         [0014]      FIG. 3  is a block diagram showing the controls of the image forming system.  
         [0015]      FIG. 4  is a flow chart showing the flow of controls of the image forming system. 
     
    
       [0016]     In the following description, like parts are designated by like reference numbers throughout the several drawings.  
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0017]     Before explaining a concrete embodiment, firstly a general post-processing apparatuses is explained briefly.  
         [0018]     In a post-processing apparatus provided with a bookbinding function, an edge portion of a stack of sheets stacked and aligned on a sheet stacking tray is held such that the sheets do not shift easily. An then the stack of sheets are bound by a binding unit so as to produce a book.  
         [0019]     As the binding unit, there may be used so much a unit which binds an edge portion of a stack of sheets with the use of a stapler or another unit which binds a stack of sheets by coating their leading edge surfaces with a hot-melt adhesive being melting. In addition to these units, there has been proposed a unit in which an adhesive is coated on edge portions of sheets discharged from an image forming apparatus, these sheets are stacked up while being aligned, and finally the edge portions of the sheets having been coated with the adhesive are pressed so that the sheets are bound. Each of these binding units described above has their own unique feature so that an appropriate unit is selected in view of the purpose of bookbinding.  
         [0020]     When binding a book with a large number of pages, the binding unit employing a stapler is not appropriate from the points of a limitation on the length of a staple pin and uneasiness in opening the book. Further, the binding unit employing coating an adhesive has also problems in the points of security of a proper binding strength and easiness in opening the book. Therefore, since the post-processing apparatus to bind sheets with a hot-melt adhesive has not such problems, it has been used so much.  
         [0021]     A procedure of binding a stack of sheets with the use of a hot-melt adhesive may be conducted as follows. Firstly, a binding tape coated with an adhesive as being a bookbinding material is pressed at a predetermined position on edge portions of sheets having been aligned. Next, a member heated to a predetermined temperature is pressed on the back surface of the binding tape so as to transfer an adhesive to the edge portions of sheets by melting the adhesive. The stack of sheets to which the adhesive has been coated is discharged to a stacking tray of the binding apparatus after the adhesive has hardened.  
         [0022]     In the heating unit that melts the adhesive on the binding tape by pressing a heated member against it, since it is necessary to heat the binding tape uniformly within a short time, an aluminum material that has good thermal conductivity or a stainless steel that has good heat accumulating ability is used for the heating member. A heater to heat the heating member is provided on a surface of this heating member that is opposite to a surface of the heating member that comes in contact with the binding tape.  
         [0023]     Since the heating member is required to have strength to withstand a pressure during its application to the binding tape and to have a uniform temperature distribution, its heat capacity naturally becomes larger. As a consequence, a warm-up period, that is, a period from a time of starting passing an electric current through the heater to a time at that the heating member reaches a predetermined temperature suitable for binding becomes longer. Therefore, even when the preparations of the image forming apparatus have been completed, a waiting time until starting an image forming operation becomes longer.  
         [0024]     In order to eliminate this difficulty, it may be considered to shorten the warm-up period by increasing the capacity of the heater and by supplying a large electric power to it. However, usually, there is a limitation on the power that can be supplied by a power distribution board or a power socket to which the apparatus is connected, Therefore, naturally, there is a limitation on the power that can be supplied to the heater. In particular, when a bookbinding apparatus is connected to an image forming apparatus having a fixing unit working with an aid of a heating roller, since it becomes necessary to supply simultaneously electric power to plural heaters for warm-up, an electric power supplied to each of the heaters is inevitably restricted. Accordingly, there may be a tendency that the warm-up period becomes longer more.  
         [0025]     Hereinafter, a preferred embodiment related to an image forming apparatus according to the present invention and to an image forming system structured by an image forming apparatus and a post-processing apparatus is described.  
         [0026]      FIG. 1  is a schematic view showing an image forming system in which a post-processing apparatus being a bookbinding apparatus an image forming apparatus are coupled to.  
         [0027]     The image forming apparatus A is a digital type copying equipment that forms images by using a conventionally known electro-photographic technology. An automatic document feeding apparatus  1  is provided on a upper portion of the image forming apparatus A. Further a bookbinding apparatus B is connected to the image forming apparatus A.  
         [0028]     The image forming apparatus A is configured to comprise an automatic document feeding apparatus  1 , a reading unit  2 , a writing unit  3 , an image forming unit  4 , a fixing unit  5 , a reversing sheet discharge unit  6 , a re-feeding unit  7 , a sheet transporting unit  8 , a sheet feeding unit  9 , a control unit C 1 , and an operation and display unit E, etc.  
         [0029]     The automatic document feeding apparatus  1  sends out document D placed on a document placing tray  10  one by one to a document transporting path  11  and discharges the document onto a document discharging tray  12 . In the course of transportation, a reading unit  2  reads out an image surface of the document D at a document reading position  13 . When reading out images on both sides of the document D, the document D whose 1 st  side has been read out is reversed by a reversing unit  14  and is sent again to the document transporting path  11 . And then, the 2 nd  side of the document D is read out. Thereafter, the document is discharged onto the document discharging tray  12 .  
         [0030]     The reading unit  2  is configured to comprise a light source  21 , a first mirror unit  22 , a second mirror unit  23 , an image forming lens  24 , and a CCD device  25 , etc. And the reading unit  2  scans the image surface of the document D being passing over the image reading position  13 . Whereby the scanned image is formed on the CCD device  25  and document image information which is optical information of the scanned image is converted into electrical information. The converted document image information is subjected to processes of A/D conversion, shading correction, compression, and so on and is stored in a memory M 1  of a control unit C 1 .  
         [0031]     The writing unit  3  is a scanning optical system comprising a laser light source, a cylindrical lens, and a Fθ lens, a mirror, a polygon mirror, etc. And, the writing unit  3  scans over a surface of a photoreceptor  41  of the image forming unit  4  with a laser beam that varies in accordance with the image information read from the memory M. Whereby the writing unit  3  forms a latent image on the surface of the photoreceptor  41 .  
         [0032]     The image forming unit  4  carries out a developing operation for the latent image formed on the surface of the photoreceptor  41  in a developing unit  42  and visualizes it as a toner image. An image transferring unit  43  transfers the toner image onto a sheet P sent out by a registration roller  81 . After the toner image has been transferred from the surface of the photoreceptor  41 , the surface of the photoreceptor  41  is cleaned by a cleaning unit  44  so as to remove residual toner and charged by an electrostatic charging unit  45 . And thereafter the surface of the photoreceptor  41  is provided to a next latent image formation.  
         [0033]     A fixing unit  5  fixes the toner image on the sheet P by heating and applying pressure on the sheet P carrying the toner image by the use of a heating roller  51  and a pressure roller  52  which are placed opposite to each other.  
         [0034]     The sheet P on which the image fixing has been completed is sent to a bookbinding apparatus B by a sheet discharging roller  55 .  
         [0035]     When discharging the sheet after reversing it, the sheet P is guided downwards by a sheet discharging guide  57 . And then, a trailing edge of the sheet P is pinched and held by a reversing roller  61  of a reversing unit. Whereby the sheet is reversed and sent out to the sheet discharging roller  55 .  
         [0036]     When carrying out an image formation on both sides of a sheet P, the sheet P is sent to a re-feeding unit  7  via the sheet discharging guide  57  and a plurality of rollers. Then, the sheet P is reversed by the reversing roller  71  of the re-feeding unit  7 , and is sent out again to the sheet transporting unit  8 .  
         [0037]     The sheet transporting unit  8  transports a sheet P fed out from a sheet feeding unit by a sheet transporting path constructed by a plurality of rollers and a guide member. And, the sheet transporting unit  8  further transports it toward a photoreceptor to make it to receive a toner image after bring a leading edge of the sheet P in contact with a registration roller.  
         [0038]     The sheet feeding unit  9  is configured to comprise the first sheet feeding unit  91  that has a small capacity tray, the second sheet feeding unit  92  that has a large capacity tray, and the third sheet feeding unit  93 . Each of the sheet feeding units has respective feeding rollers  916 ,  926 , and  936  each of which feeds out a sheet P stacked in each tray one by one toward the sheet transporting unit  8 . In addition, in each of the second sheet feeding unit  92  and the third sheet feeding unit  93 , there is provided a top surface detection unit that detects the position of the top surface of stacked papers. Then, the control unit C 1  moves up or down the bottom surface of the tray in which sheets P are stacked, based on the top surface detection signal from the detection unit.  
         [0039]     The operation and display unit E is a touch panel installed on the top surface of the main body of the image forming apparatus A and has both functions of inputting and displaying. Therefore, the operation and display unit E is used to conduct an instructing operation for a control unit C 1  with regard to setting a bookbinding mode, such setting the number of copies and setting whether or not to carry out a bookbinding operation. In addition, this unit also has a function of displaying warm-up information described later.  
         [0040]     If the bookbinding mode has been selected by using the operation and display unit E, a sheets P on which an image formation has been done by the image forming apparatus A and which have been sent out to the bookbinding apparatus is guided by a separation guide  101  to proceed upward and discharged onto a sheet discharging tray  102 .  
         [0041]     When the bookbinding mode has been selected, plural sheets to be bound are serially conveyed to a sheet aligning unit  200  and thereby being stacked. In addition, it is possible that a cover sheet or a insert sheet to be inserted between specific pages is stacked in sheet stacking units  910  and  920  and the sheet transporting unit  100  conveys these sheets to the sheet aligning unit  200 . Whereby these sheets are inserted at a position of a specific page number of the plural sheets stacked by the sheet aligning unit  200 .  
         [0042]     The sheet aligning unit  200  is configured to comprise a sheet stacking tray  201 , a leading edge aligning plate  202 , a sheet pressing members  203  and  204 , a roller  205 , and a sheet width aligning plate (not shown in the figure), etc. Sheets P stacked in the stacking tray  201  have their leading edges aligned by the leading edge aligning plate  202  and their both side edges aligned by the width aligning plate, thereby becoming an aligned stack of sheets. A binding unit  300  described later conducts a binding operation for this aligned stack of sheets, whereby the bookbinding operation is completed.  
         [0043]     When the stacking of the last page is completed, sheet pressing members  203  and  204  press a leading edge portion of a stack of sheets P from both of top and bottom surfaces of the stack of sheets P. Whereby the stack of sheets is tightly pinched such that the alignment of the stacked sheets does not collapse. When this pinching by the sheet pressing members  203  and  204  has been completed, the leading edge aligning plate  202  moves in the direction of an arrow “b” shown in the drawing. As a result, the leading edge of the stack of sheets faces against the binding unit  300  with a binding tape TT placed in between them.  
         [0044]      FIG. 2  is a schematic diagram showing the peripheral parts near the binding unit  300 .  
         [0045]     The binding unit  300  is configured to comprise a binding tape TT that is coated with a hot-melt type adhesive; a binding tape transporting unit (not shown in  FIG. 2  but shown in  FIG. 3 ) that cuts the binding tape TT to a specific length and sends it from a tape supply roll section (not shown in the figure) to a main heater unit  310 ; the main heater unit  310  that presses the binding tape TT from a back surface of it against a leading edge surface of the aligned stack of sheets while heating it; and side surface heating units  320  and  330  that press both side surfaces of the binding tape TT onto the top surface and the bottom surface of the stack of sheets while heating it.  
         [0046]     The main heating unit  310  is configured to comprise a heating member  311 , a heater  312 , and a temperature detection unit TS 1  (not shown in  FIG. 2  but shown in  FIG. 3 ), etc. The heating member  311  is controlled to maintain a specific temperature by the temperature detection unit TS 1  and the control unit C 2 . Further, although the side surface heating units  320  and  330  are different in shape from the main heating unit  310 , they are constructed by heating members, heaters, and temperature detection units as similar as the main heating unit  310 .  
         [0047]     After the heating has been started for the heating member  311 , when the temperature detection unit TS 1  detects that the temperature of the heating member  311  has reached the melting temperature of the hot-melt adhesive, the control unit C 2  transmits warm-up completion information to a control unit C 1  of the image forming apparatus.  
         [0048]     The main heating unit  310  of the binding unit  300  is moved by a heating unit moving unit (not shown in the drawings) in the direction of an arrow “a” shown in the drawings, and presses the binding tape TT against the leading edge surface of the stack of sheets. With this operation, the adhesive of the binding tape TT melts and transfers to the leading edge surface of the stack of sheets.  
         [0049]     Next, binding tape side surface guides  321  and  331  are moved in the directions of arrows d 1  and d 2  respectively, and bend the side surfaces of the binding tape towards the topmost surface and the bottommost surface of the stack of sheets. When the movements of the binding tape side surface guides  321  and  331  are completed, side surface heating units  320  and  330  are moved in the directions of arrows f 1  and f 2  respectively, and press the both bent side surfaces of the binding tape TT onto the topmost surface and the bottommost surface of the stack of sheets while heating the both bent side surfaces of the binding tape TT.  
         [0050]     When a previously set pressing time has elapsed, the main heating unit  310  and the side surface heating units  320  and  330  return to their original positions and then separate from the stack of sheets. With this operation, the temperature of the melted adhesive of the binding tape TT drops suddenly thereby the adhesive harden. Accordingly, the stack of sheets is bound at its leading edge surface by the hardened adhesive.  
         [0051]     The sheet aligning unit  200  is moved to the position shown by dotted lines in  FIG. 1  while still holding the bound stack of sheets by the pressing members  203  and  204 . Thereafter, the pressing by the pressing members  203  and  204  is released, and a roller  205  provided on the stacking tray  201  is raised above the stacking surface and rotated so that the bound stack of sheets is transported to a bound sheet stack loading tray  400 .  
         [0052]      FIG. 3  is a block diagram showing a control relationship of the image forming system comprising the image forming apparatus A and the bookbinding apparatus B according to the present embodiment.  
         [0053]     A control unit C 1  of the image forming apparatus is a computer system that is configured to comprise a CPU, an operation unit, a memory unit M 1 , an input/output I/F (interface), a communication unit, and drive circuits, etc. Programs having been stored beforehand in the memory unit M 1  are executed so that the control for each of these units is carried out. In addition, the input/output interface is connected with an input port for receiving the warm-up completion information transmitted by the control unit C 2  of the binding apparatus. Further, a control unit C 2  of the binding apparatus comprises a structure which is smaller than the structure of the control unit C 1 , but is almost the same with it. The input/output I/F is connected with an output port for transmitting the warm-up completion information. Incidentally, the description of blocks that are not necessary for explaining the present preferred embodiment has been omitted.  
         [0054]      FIG. 4  is a flow chart showing the flow of detecting the warm-up state of the binding apparatus and controlling the image forming system based on the results of the detection.  
         [0055]     Firstly, when an instruction for an image forming operation is input from the operation and display unit E of the image forming apparatus A (Step S 1 ), the control unit C 1  detects whether or not a bookbinding mode has been set in the operation and display unit E (Step S 2 ).  
         [0056]     When the bookbinding mode has not been selected (Step S 2 : N), the control unit C 1  sends the non-selection information to switch off the bookbinding apparatus to the control unit C 2 . Upon receipt of this non-selection information, the control unit C 2  moves a separating guide  101  to a predetermined position so as to discharge sheets, on which images are formed, onto the sheet discharging tray  102  of the bookbinding apparatus B. Further, the control unit C 2  also switches OFF heaters of the main heating unit  310  and the side surface heating units  320  and  330  of the binding unit  300  (Step S 3 ). The image forming apparatus A carries out image formations of the number of sheets set in the operation and display unit E and discharges the sheets onto the sheet discharging tray  101  of the bookbinding apparatus B (Step S 4 ).  
         [0057]     When the bookbinding mode has been selected (Step S 2 : Y), the control unit C 1  sends to the control unit C 2  information that the bookbinding apparatus B has been selected. Then, the control unit C 2  having received the information switches ON the heaters provided in the heating units of the binding unit  300  (Step S 5 ).  
         [0058]     After waiting until a sheet P becoming the last page of the first copy of a book to be bound is fed to an image formation (Step S 6 ), the control unit C 1  keeps a sheet P becoming the first page of the next second copy of the book on a sheet feed standby state (Step S 7 ). When the sheet P becoming the last page of the first copy of the book is stacked in the sheet aligning unit  200  (Step S 8 : Y), the warm-up situation of the binding unit  300  is judged by the control unit C 2  (Step S 9 ). If the warming up has not been completed (Step S 9 : N), a waiting time until the warming up has been completed is indicated on the operation and display unit E (Step S 10 ), and completion of the warming up is awaited (Step S 9 ). If the warming up has been completed (Step S 9 : Y), the binding unit  300  starts a binding operation for the first copy of the book (Step S 11 ) and also stars a timer to count a predetermined time period necessary for the binding operation (Step S 12 ).  
         [0059]     When the counting of the predetermined time period by the timer has been completed (Step S 12 : Y), confirmation is made for whether or not the binding for the set number of copies of the book has been completed (Step S 13 ). Then, if it has been completed (Step S 13 : Y), all the heaters of the binding unit  300  are switched OFF (Step S 14 ) and the control escapes from this routine. If it has not been completed (Step-S 13 : N), feeding a sheet is conducted for forming an image of the first page of a next successive copy of the book (the second copy of the book in the current example, but referred as the N i   th  copy of the book for generalization) (Step S 15 ). When a sheet P becoming the last page of the N i   th  copy of the book has been fed out (Step S 16 : Y), a sheet becoming the first page of the N i+1   th  copy of the book following the N i   th  copy of the book is kept on the sheet feed standby state (Step S 17 ). And then, the control waits until a sheet becoming the last page of the N i   th  copy of the book is stacked in the sheet aligning unit  200  (Step S 18 ). Thereafter, the control returns to Step  11  and the similar operations are continued until the bookbinding for the set number of copies of the book has been completed.  
         [0060]     In the above embodiment, although feeding a sheet becoming the first sheet of the second copy of the book is kept in a standby condition (Step S 7 ) after a sheet becoming the last page of the first copy of the book has been fed out, it is not necessary to carry out the control in this manner. For example, in order to improve the work efficiency of the bookbinding apparatus after the warming up process has been completed, it may be considered to provide at an upstream side of the sheet aligning unit a stacking tray capable of holding the number of sheets on which images are formed during the predetermined time period for conducting the bookbinding operation. In the case of such a configuration, it may be possible to control as follows. Feeding a sheet for the second copy of the book is continued even after a sheet becoming the last page of the first copy of the book is fed out. And then, sheets on which image formations have been completed are stacked in the stacking tray. Incidentally, when the stacking tray becomes full even before the warming up process has been completed, it is necessary at that time to control to make feeding a sheet for the second copy to be on a standby condition.  
         [0061]     Namely, it is possible to speed up starting the bookbinding operation for the first copy of the book by the following controlling manners: With regard to sheets for the first copy, regardless of the warm-up information of the bookbinding apparatus, sheets are stacked in the sheet aligning unit  200 . And then, with regard to sheets for the second copy of the book, operations of the image forming apparatus are controlled based on the warm-up information of the bookbinding apparatus.  
         [0062]     Although the present invention has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications are apparent to those skilled in the art. Such changes and modifications are to be understood as included within the scope of the present invention as defined by the appended claims unless they depart therefrom.