Patent Publication Number: US-7588382-B2

Title: Sheet processing apparatus and image forming apparatus

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a sheet processing apparatus for executing a predetermined processing on a sheet on which an image is formed and an image forming apparatus provided with this sheet processing apparatus. 
   2. Description of the Related Art 
   In recent years, an electrophotographic type image forming apparatus for forming a high quality image such as silver halide photography has been developed. In such an image forming apparatus, a L-size (photographic size) smaller than postcard-size cannot be used. Thus, a conventional image forming apparatus has adopted a method in which a photographic image is imposed on the A4 size sheet and this sheet is cut into a predetermined dimension if the photographic size like the L size is desired as an output object. As a cutting device for cutting this sheet into a specified dimension, technology disclosed in Japanese Patent Application Laid-Open No. 10-76495 has been generally known. According to Japanese Patent Application Laid-Open No. 10-76495, an output object on which an image is recorded with an image forming apparatus or the like is placed on a supporting base plate of the cutting device off line and then cut into a predetermined dimension. 
   When an output object same as a certain output object of those created in the above-described manner is produced again, the color and density of the output object needs to substantially coincide with those of the output object created in advance. However, it is often difficult for an operator not skilled in image processing to output an image having the same quality as the preceding output object, thereby taking a long time for that processing, so that waste of material increases due to generation of unacceptable printed products. 
   To meet such a problem, a print system capable of outputting a print image having the same color and density as a previous output product has been proposed. For example, the print system disclosed in Japanese Patent Application Laid-Open No. 2000-10207 records image processing information indicating an image processing method applied to each image on the back surface of an output product when printing an input image such as an image taken with a digital camera or the like. Then, when creating a print having the same color and density as that output product, the image processing information of the output product to be reproduced again is read from the back surface of the output product and the same image processing is executed based on that information. 
   However, if the cutting device disclosed in Japanese Patent Application Laid-Open No. 10-76495 and the print system disclosed in Japanese Patent Application Laid-Open No. 2000-10207 are connected as an electrophotographic type image forming apparatus capable of cutting an output product and recording image processing information on the back surface of the output product, the size of the entire apparatus increases, which is a problem to be solved. Further, productivity the cutting device connected to the aforementioned print system becomes a considerably low because it cuts output products off line. Even if the cutting device is so constructed as to cut the output products on line, its productivity of printing is still low because the size of the apparatus is large. Further, the above-mentioned combination of the cutting device and apparatus induces a further drop in productivity because the output product needs to be stopped for each of both the cutting operation and the recording operation to the back surface of the product. 
   SUMMARY OF THE INVENTION 
   Accordingly, an object of the present invention is to provide a sheet processing apparatus and image forming apparatus capable of cutting a sheet and recording information on the back surface of a sheet without enlarging the size of the apparatus and drop of productivity. 
   To achieve the above-described object, the present invention provides a sheet processing apparatus for executing a predetermined processing on a sheet in which an image is recorded, comprising: a cutting unit which cuts a sheet; and a recording unit which records an information about recording to the front surface of the sheet on the back surface of the sheet, wherein an action of cutting the sheet with the cutting unit and an action of recording on the back surface of the sheet with the recording unit are executed in parallel. 
   The present invention enables cutting of the sheet and recording of information on the back surface of the sheet without a necessity of enlarging the size of the apparatus and dropping productivity. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic sectional view of an image forming apparatus; 
       FIG. 2  is a schematic sectional view of a sheet processing apparatus; 
       FIG. 3  is a schematic top view of a cutting device; 
       FIG. 4  is a construction diagram of a print device; and 
       FIG. 5  is a flow chart for explaining the operation of an image forming apparatus. 
   

   DESCRIPTION OF THE EMBODIMENTS 
   Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. 
   First Embodiment 
   An image forming apparatus having a sheet processing apparatus according to the first embodiment of the present invention will be described with reference to  FIGS. 1 to 5 . 
   (Entire Structure of Image Forming Apparatus) 
   First, the entire structure of the image forming apparatus according to this embodiment will be described.  FIG. 1  is a schematic sectional view showing the image forming apparatus according to the first embodiment of the invention. 
   According to this image forming apparatus, an image creating system (image formation part)  2  using intermediate transfer system, a sheet feeding unit  3  for supplying recording sheets and a first fixing device  4  and the like are disposed within its casing  1  constituting a main body of the apparatus. An original reading device  8  and an operation portion (not shown) are disposed above the casing  1  with a space there between. The space between the top of the casing  1  and the original reading device  8  serves as an in-apparatus sheet discharge portion in which sheets discharged from the casing  1  are supported. Further, a sheet processing apparatus for executing a predetermined processing on a sheet in which an image is recorded is attached to this space detachably. This sheet processing apparatus includes a belt fixing device  5  as a gloss applying unit for applying gloss to the sheet and a cutting device  6  for cutting the sheet. The cutting device  6  is disposed in the downstream side of the belt fixing device  5  in the conveyance direction of the sheet. 
   In this image forming apparatus, a predetermined selective instruction is made from an operation panel (not shown). As a result, first output mode (normal print mode) for executing normal image output or second output mode (photographic print mode) for outputting an image with gloss can be selected. 
   In this image forming apparatus, an image forming process pattern peculiar to each output mode is selectively setup. That is, if the normal print mode is selected upon formation of an image, a pattern for discharging without sending to the belt fixing device  5  is selected after the image is fixed with the first fixing device  4 . On the other hand, when the photographic print mode is selected, a process pattern for executing gloss processing with the belt fixing device  5  is selected after the image is fixed with the first fixing device  4 . 
   (Configuration of Image Forming System) 
   The image creating system  2  as a image formation part includes image creating units  10 Y,  10 M,  10 C,  10 PC,  10 K and  10 PM for forming toner images of six colors, yellow (Y), magenta (M), cyan (C), photo cyan (PC), black (K) and photo magenta (PM). The image creating system  2  has an intermediate transfer belt  20  for transferring toner images formed by these six image creating units  10  to transfer positions to a recording sheet. 
   The respective image creating units  10  have the same structure. The structure of the image creating unit  10 Y will be described. The image creating unit  10 Y includes a photosensitive drum  11  having organic photosensitive layer or the like on its surface and a non-fixed toner image is formed on the photosensitive drum  11  through a following electrophotographic process. That is, the surface of the rotating photosensitive drum  11  is charged equally by a charging device  12  such as a roller type. After that, the charged surface is scanned with laser beam based on an image creating data signal described later from exposing device (not shown) so as to form an electrostatic latent image. Next, the latent image is developed with toner component of developing agent supplied from the developing unit  14  so that a toner image of a predetermined color is represented. 
   The toner image formed by each image creating unit  10  is transferred primarily to an intermediate transfer belt  20  passing between each photosensitive drum  11  and the primary transfer roller  15  electrostatically. The surface of each photosensitive drum  11  after transfer is neutralized with a neutralizing unit (not shown) such as lamp type after it is cleaned with a drum cleaning unit (not shown). Reference numeral  18  (Y, M, C, PC, K, PM) denotes a toner cartridge containing toner to be supplied to the developing unit  14  of each image creating unit  10 . 
   (Structure of Intermediate Transfer Belt) 
   The intermediate transfer belt  20  is an endless belt composed of polyimide film whose volume resistivity is adjusted by adding conductive material or the like. Then, this intermediate transfer belt  20  is stretched between a drive roller  21 , a backup roller  22  of a secondary transfer portion and a plurality of driven rollers  23 ,  24 . The intermediate transfer belt  20  is disposed such that it makes contact with the photosensitive drums  11  of the respective image creating units between the driven rollers  23  and  24  and rotated in the direction of an arrow A. 
   (Structure of Sheet Feeding Unit) 
   The sheet feeding unit  3  includes a plurality of sheet cassettes  31 A,  31 B,  31 C,  31 D which accommodate a plurality of recording sheets separately depending on the size. This sheet feeding unit  3  feeds each recording sheet from the sheet cassette  31  by unit of the sheet sending device  32 . This recording sheet is conveyed to a resist roller  33  through a sheet conveyance path  71  constituted of a plurality of conveyance rollers, guide members and the like. After that, the recording sheet is sent to a secondary transfer position meeting a secondary transfer timing by unit of the resist roller  33 . 
   The recording sheet is not restricted to any particular one as long as it can be conveyed within this image forming apparatus and the toner image can be transferred and fixed. As this recording sheet, usually, a plain sheet or coated sheet of specified size such as A4, B5 is used. Such a sheet is used when an image is formed under the above-mentioned normal print mode. 
   The toner image transferred to the intermediate transfer belt  20  is conveyed to the secondary transfer position between a secondary transfer roller  25  disposed to oppose the backup roller  22  and the belt  20  in a condition in which it is carried by the belt  20 . The toner image is transferred secondarily to a recording sheet of a predetermined size supplied to the secondary transfer position from the sheet cassette  31  electrostatically. The surface of the intermediate transfer belt  20  after the secondary transfer is cleaned by unit of a belt cleaning unit  26 . 
   (Structure of First Fixing Device) 
   A heating roller  41  and a pressure belt  42  are disposed in a pressure contact condition within the first fixing device  4 . In the heating roller  41 , elastic layer and toner parting layer are formed on a metallic cylindrical roller composed of aluminum or the like while a heating source such as a halogen lamp is disposed within the roller. In the pressure belt  42 , the separation layer is formed on a belt base material composed of polyimide film or the like. A pressure pad for forming a nip by pressing the belt to the heating roller  41  is disposed within the pressure belt  42 . 
   There are provided a conveyance path  36  for conveying the recording sheet after the first fixing is finished to the belt fixing device  5  and a conveyance path  37  which branches the recording sheet halfway of the conveyance path  36  and discharges the recording sheet to a discharge tray outside the casing  1  in the downstream side of the first fixing device  4 . 
   After the toner image is transferred secondarily, the recording sheet is heated and pressurized when it passes the nip between the heating roller  41  and the pressure belt  42  after it is sent into the first fixing device  4 . Consequently, the toner image is fixed to the recording sheet. After the first fixing is finished by the first fixing device  4 , the recording sheet is conveyed through any of following process patterns. According to one pattern, when the aforementioned normal print mode is selected, the recording sheet is sent to the conveyance path  37  for discharge by a guide of a conveyance direction switching gate  35  and discharged out of the casing by a discharge roller. According to another pattern, when the aforementioned photographic print mode is selected, the recording sheet is sent to the conveyance path by a guide of the conveyance direction switching gate  35  and discharged to the in-apparatus sheet discharge portion or sent to a sheet processing apparatus. 
   (Structure of Original Reading Device) 
   The original reading device  8  reads out reflected light of an image from the original with a CCD sensor by irradiating an original to be copied with light source, executes a predetermined image signal processing on the signal and inputs that signal as image data. The image data read by this original reading device is sent to an image processing unit (not shown) through a transmission cable. This image forming apparatus includes a memory medium reading unit for inputting image data recorded in a memory medium, a communication input unit for inputting image data created by an external connection device through communication cable, radio or the like, and the like so as to fetch these image data. Particularly, image pickup data of a digital camera can be fetched in. 
   A variety of image data input from this original reading device  8 , the memory medium reading device and communication input unit are converted to image creation data through a predetermined image processing (color conversion processing, resolution processing, magnification changing processing, processing/editing processing and the like) in image processing unit. Further, the converted image creation data is sent to an exposing unit (not shown) in the image creating system  2  and used for the above-described image creation process. 
   This image forming apparatus overlays toner images of six colors formed by the six image creating units  10  (Y, M, C, PC, K, PM) on the intermediate transfer belt  20  successively to achieve the primary transfer. After that, the multiple toner images are transferred secondarily to the recording sheet in batch so as to form a full-color image. Further, a single color image such as a monochrome image may be formed by transferring a black toner image created by actuating only part of the image creating units, for example, the image creating unit  10 K for black of the six image creation units  10  (Y, M, C, PC, K, PM) to the recording sheet through the intermediate transfer belt  20 . 
   (Structure of Belt Fixing Device) 
   The belt fixing device  5  is used in conditions in which it is disposed at in-apparatus portion of a space between on the top of the casing  1  of the image forming apparatus and the original reading device  8 . 
   Although the belt fixing device  5  functions as a unit for providing with gloss, according to this embodiment, it is disposed in the downstream side in the sheet conveyance direction of the first fixing device  4  disposed within the casing  1  and used as a second fixing device. 
   As shown in  FIG. 2 , the belt fixing device  5  includes a fixing belt  54  which rotates in the direction of an arrow B. The fixing belt  54  is applied around a heating roller  51 , a separation roller  52  and a steering roller  53 . Further, the belt fixing device  5  includes a pressure roller  55  for forming a nip by pressing the fixing belt  54  to the heating roller  51  and a cooling device  56  for cooling a portion in the downstream side of the nip of the fixing belt  54 . 
   The heating roller  51  and the pressure roller  55  constitute a heating and pressurizing units. In the heating roller  51 , a metallic cylindrical roller having a high heat conductivity is coated with elastic layer and a heating source such a halogen lamp is disposed within that roller. On the other hand, in the pressure roller  55 , a metallic cylindrical roller having a high heat conductivity is coated with elastic layer and separation layer in this order and a heating source such as a halogen lamp is disposed within the roller. 
   The separation roller  52  separates the recording sheet from the fixing belt  54  by the stiffness of the sheet it self. The external dimensions of this separation roller  52  are determined depending on adhesion force between the fixing belt  54  and the recording sheet and a winding angle between the fixing belt  54  and the separation roller  52 . 
   The steering roller  53  aims at moving and adjusting the fixing belt  54  by a predetermined amount in a direction perpendicular to a rotation direction (direction of an arrow B) so as to make the fixing belt  54  pass a predetermined position in the direction perpendicular to the rotation direction. 
   The fixing belt  54  is produced by coating an endless film composed of thermosetting type polyimide with surface layer composed of silicone rubber smooth in its surface. The cooling device  56  is used for cooling the recording sheet adhering to the fixing belt  54  practically. This cooling device  56  is disposed in an inside area of the fixing belt  54  between the heating roller  51  and the separation roller  52  so as to absorb heat from the fixing belt  54  in a condition in which it makes a contact with its inner peripheral face. 
   A guide  58  is disposed in the upstream side of the belt fixing device  5  in the sheet conveyance direction via the fixing belt  54  and the conveyance roller  59  is disposed in the downstream side. 
   (Structure of Cutting Device) 
     FIG. 2  is a side sectional view of the cutting device  6  of this embodiment.  FIG. 3  is a top view of the cutting device  6 . A conveyance roller  65  is disposed in the upstream side of the cutting device  6  in the sheet conveyance direction. The conveyance roller  65  is driven by a drive motor  101 . A pair of rotary wheel type cutters  71   a ,  71   b  as a second cutting unit for cutting the recording sheet and a pair of rotary wheel type cutters  72   a ,  72   b  are disposed in the downstream side of the conveyance roller in the sheet conveyance direction. The conveyance rollers  66  is disposed between the rotary wheel type cutters  71  and  72 . The conveyance rollers  67  is disposed in the downstream side of the cutters  72 . The conveyance rollers  66 ,  67  are driven independently by drive motors  103 ,  104 . The cutters  71 ,  72  are driven by a motor  102 . The cutters  71   a ,  71   b  and type cutters  72   a ,  72   b  are independent and movable in a direction perpendicular to the sheet conveyance direction. Although the cutters  71   a ,  71   b  and the cutters  72   a ,  72   b  are disposed separately in the upstream and downstream side, they may be provided coaxially. Although the cutters  71   a ,  71   b  are provided to cut both side ends of the sheet and the cutters  72   a ,  72   b  are provided to cut the sheet central portion, both of them do not need to be provided but only any one of them may be provided depending on the size of the recording sheet for use. In the embodiment, the structure in which the rotary wheel type cutter for cutting the sheet with a disk-like cutter is adopted is described, but the invention is not limited to this structure. For example, a guillotine type cutter which is described later may be used. 
   A guillotine type cutter unit  80  is disposed in the downstream side of the conveyance roller  67 . This guillotine type cutter unit  80  includes printing devices  81   a ,  81   b  as a recording unit, the cutter  73  as a first cutting unit and a sheet detecting sensor  74  provided integrally. The cutter  73  is driven by a motor  105 . The cutter  73  cuts the recording sheet in a direction perpendicular to the sheet conveyance direction. Although according to this embodiment, the printing device  81  and the cutter  73  are integrated into a unit with the cutter unit  80 , the present invention is not restricted to this example. For example, it is permissible to integrate the printing device  81  with the cutters  71 ,  72  for cutting the recording sheet in the sheet conveyance direction. Further, it is not necessary to equip both the cutter  73  and the cutters  71 ,  72  as cutting units and any one of them may be integrated with the printing device  81  depending on the size of the recording sheet for use. Although all of them may be integrated into a single unit, it is preferable to construct a minimum unit structure necessary from viewpoints of miniaturization. 
   The printing device  81  records information about image recorded to the front surface of a sheet and information about print condition and the like on the back surface of the recording sheet. According to this embodiment, as shown in  FIG. 4  dot printing method in which a print head  81   m  forms dots successively by rotating an ink ribbon  81   n  installed on a dot printing device main body  81   p  is employed. In the meantime, the recording method is not restricted to the above-described method, but may be other recording method. 
   The printing devices  81   a ,  81   b  are movable in the direction perpendicular to the sheet conveyance direction independently. Time required for a recording operation can be reduced by providing plural printing devices such that they are movable independently. This print unit can meet various sizes from a small one to a large one by disposing the printing devices in line in the direction perpendicular to the sheet conveyance direction. The guillotine type cutter  73  cuts the recording sheet in the direction perpendicular to the sheet conveyance direction. The sheet detecting sensor  74  is a detecting portion for detecting the front end in the conveyance direction of the sheet. 
   The rotary wheel type cutters  71 ,  72  are disc-like cutting blades and each comprised of a pair of upper wheel blade and lower wheel blade, located up and down. The cutters  71 ,  72  are installed freely rotatably on a predetermined position of supporting shafts disposed up and down in parallel in the direction perpendicular to the sheet conveyance direction such that the upper wheel blade and lower wheel blade cross each other while partially in contact within the recording sheet conveyance path. Cutting by the cutters  71 ,  72  is automatically carried out when the recording sheet is passes the portion in which the upper wheel and lower wheel cross each other in a contact condition. 
   The guillotine type cutter  73  is a sheet-like cutting blade which includes a pair of a movable blade  73   a  and a fixed blade  73   b . In this cutter  73 , the movable blade  73   a  and the fixed blade  73   b  are disposed in parallel at a predetermined gap along the sheet conveyance direction and they are disposed up and down in the direction perpendicular to the conveyance direction. The fixed blade  73   b  is disposed to be located in the conveyance path of the recording sheet. On the other hand, the movable blade  73   a  is fixed to the cutter unit  80  and the cutter unit  80  can be displaced in a direction (vertical direction) of approaching to/parting from the fixed blade  73   b . Then, the movable blade  73   a  and the fixed blade  73   b  are so constructed to approach and cross each other so as to cut the recording sheet. In this cutting operation with the cutter  73 , the front end in the conveyance direction of the recording sheet is detected with the sheet detecting sensor  74  and the recording sheet is stopped and cut after a predetermined timing. 
   The movable blade  73   a  and the printing device  81  are so constructed to move to an actuation position which allow them to be actuated and a non-actuation position which block them from being actuated. That is, the printing device  81  is displaced vertically at the same time as a cutting timing of the cutter  73 . When the cutter unit  80  descends (moves to the actuation position) so that the recording sheet is cut out by the cutter  73 , the printing device  81  prints on the back surface of the recording sheet. That is, an action of cutting the recording sheet with the cutter  73  as a cutting unit and an action of recording on the back surface of the recording sheet with the printing device  81  as a recording unit are carried out in parallel. 
   (Description of Operation) 
   Next, the operation of the above-described image forming apparatus will be described.  FIG. 5  is a flow chart for explaining the operation. 
   First, a predetermined selection instruction is carried out from an operation panel (not shown) (S 101 , S 102 ). Normal print mode for executing normal image output or photographic print mode is selected. If the normal image output is executed, the recording sheet feeding operation is carried out (S 104 ) after input image data is read in (S 103 ) so as to execute image formation action (S 105 ). After that, first fixing is executed with the first fixing device  4  (S 106 ) and the recording sheet is discharged by a discharge roller  91  via the conveyance path  37  (S 107 , S 108 ). 
   Next, a case where photographic print mode is selected will be described. This photographic print mode is the same as the normal print mode for executing the normal image output (S 102 -S 106 ) up to the first fixing action (S 109 -S 112 ). After the first fixing action is finished, the recording sheet discharged from the first fixing device  4  is conveyed to the belt fixing device  5  by the conveyance direction switching gate  35  (S 113 , S 114 ). At this time, the recording sheet is conveyed to the belt fixing device  5  with a front surface of the sheet (sheet surface) on which photographic type print is made, facing down in contact with the fixing belt  54 . 
   Following gloss applying processing is carried out by the belt fixing device  5  (S 115 ). First, the recording sheet is heated and pressurized when it passes a nip between the fixing belt  54  and the pressure roller  55  and after it passes the nip, conveyed in a condition in which it adheres to the fixing belt  54 . Subsequently, the sheet adhering to the fixing belt  54  is cooled up to a predetermined temperature by the cooling device  56  and after that, separated from the fixing belt  54  at the separation roller  52 . Consequently, a toner image fixed to the first fixing device  4  is fixed to the recording sheet with feeling of gloss given to the toner image as a result of transfer a smooth surface of the fixing belt  54 . 
   Next, the recording sheet discharged from the belt fixing device  5  by the conveyance roller  59  is conveyed to the cutting device  6 . The cutting device  6  adopts a different sequence depending on a large size like size A4 or a small size like size L (S 116 ). 
   When a small size sheet like size L is created by cutting, the rotary wheel type cutters  71 ,  72  move in the direction perpendicular to the sheet conveyance direction depending on the size of an output sheet input by the operation panel and stands by at a desired position (S 117 ). Then, the recording sheet conveyed to the cutting device  6  is conveyed within the unit by the conveyance rollers  65 ,  66 . In this while, both side ends of the sheet are cut down when the recording sheet passes the cutter  71  (S 118 ). Further, the sheet central portion is cut when the recording sheet passes the cutter  72  (S 118 ). The central portion of the recording sheet is cut in order to create four sheets of size L from a recording sheet of size A4. 
   On the other hand, if a large size sheet like size A4 is created, the cutter  72  is retreated to a cutting impossible position because the central portion of the recording sheet does not need to be cut (S 122 ). On the other hand, the cutter  71  is adjusted to a desired position and stands by depending the size of an output sheet input through the operation panel (S 123 ). The printing device  81   b  which cancels its print action of the plural printing devices  81   a ,  81   b  is moved from a sheet passage area to the retreat position corresponding to the retreat action of the cutter  72  (S 124 ). The recording sheet conveyed to the cutting device  6  is conveyed within the apparatus by means of the conveyance rollers  65 ,  66  and both side ends of the sheet are cut out when the recording sheet passes the rotary wheel type cutter  71 . 
   When a predetermined time elapses since the front end portion of the recording sheet is detected by the sheet detecting sensor  74 , the sheet conveyance action of the conveyance rollers  65  to  68  is stopped temporarily. The movable blade  73   a  of the guillotine type cutter  73  descends after the sheet conveyance action is stopped and approaches and crosses the fixed blade  73   b . Consequently, the front end side of the recording sheet is cut in the direction perpendicular to the sheet conveyance direction (S 119  or S 126 ). Information about recording to the front surface of the sheet (image No. of surface image file, color correction data at the print time and the like) is recorded on the back surface of the recording sheet by the printing devices  81   a ,  81   b  while moving the print units  81   a ,  81   b  in the direction perpendicular to the sheet conveyance direction with the movable blade  73   a  descended (S 119  or S 126 ). Necessity of stopping the recording sheet for cutting action and recording action is eliminated by executing the recording action on the back surface of the recording sheet synchronously with the up/down motion of the movable blade  73   a . That is, cutting of the sheet and recording of information on the back surface of the sheet are enabled without dropping productivity. 
   The sheet conveyance action of the conveyance rollers  65  to  68  is restarted when cutting of the rear end of the recording sheet with the guillotine type cutter  73  is terminated (S 120  or S 127 ). After that, a cut recording sheet is discharged to the discharge tray  69  by the conveyance roller  68 . 
   According to this embodiment, as described above, the cutter  73  and the printing device  81  are provided integrally as the unit  80  and the action of cutting the recording sheet with the cutter  73  and the action of recording on the back surface of the recording sheet with the printing device  81  are executed in parallel. Consequently, cutting of the sheet and recording of information on the back surface of the sheet are enabled without enlarging the size of the apparatus and dropping productivity. 
   Other Embodiment 
   Although according to the above-described embodiment, the recording action is carried out by the printing device  81  during the cutting action of the guillotine type cutter  73 , the guillotine type cutter  73  may cut out during the recording action of the printing device  81 . Any structure may be adopted if the cutting action by the guillotine type cutter  73  and the recording action by the printing device  81  are executed in parallel. 
   Although the above-described embodiment exemplifies a structure in which the sheet processing apparatus including the cutter as a cutting unit and the printing device as a recording unit is disposed detachably in the apparatus of the image forming apparatus, the present invention is not restricted to this example. The structure in which sheet processing apparatus is disposed detachably outside of the image forming apparatus. At this time, the belt fixing device  5  as a gloss applying unit is disposed outside of the image forming apparatus and further disposed in the upstream of the cutting device  6 . 
   Although according to the above embodiment, two printing devices are provided as the recording unit, the present invention is not restricted to this example, but a printing device may be permitted. In this case, the printing device is provided to be movable in the direction perpendicular to the sheet conveyance direction or the width of a print area in the direction perpendicular to the sheet conveyance direction of the printing device is set substantially same as the width of a sheet which can be conveyed. 
   Although the above embodiment exemplifies the sheet processing apparatus which is attached detachably to the image forming apparatus, the present invention is not restricted to this example. For example, the sheet processing apparatus may be included in the image forming apparatus and when the present invention is applied to the sheet processing apparatus, the same advantage can be expected. 
   Although the above embodiment exemplifies a structure in which the image creating system as an image formation part includes six image creating units, the quantity of the image creating units is not restricted to this example, but may be set up appropriately depending on a necessity. 
   Although the above embodiment exemplifies a copying machine as the image forming apparatus, the present invention is not restricted to this example, but it is permissible to adopt for example, a printer, facsimile machine or the like as other image forming apparatus. Alternatively, other image processing apparatus such as a complex machine which combines these functions may be adopted. The image forming apparatus may be so constructed to adopt a transfer material bearing member which bears and transfer a sheet and transfer toner images of respective colors to the transfer material borne by the transfer material bearing member successively such that they are overlaid. By applying the present invention to the sheet processing apparatus for use in such an image forming apparatus, the same effect can be obtained. 
   This application claims the benefit of priority from the prior Japanese Patent Application No. 2005-229176 filed on Aug. 8, 2005 the entire contents of which are incorporated by reference herein.