JP2005070494A - Image forming apparatus - Google Patents

Abstract

An object of the present invention is to provide an image forming apparatus including a sheet processing apparatus capable of effectively cooling a held sheet without increasing the size of the apparatus and reducing the cost.
A representative configuration of an image forming apparatus according to the present invention is configured to perform exhaust toward an outside in an image forming unit that forms an image on a sheet and a sheet discharge unit that discharges a sheet on which an image is formed. An image forming apparatus comprising: an image forming apparatus main body having a blowing unit; and a sheet processing apparatus that receives and conveys a sheet discharged from the image forming apparatus main body, and exhausts exhaust air from the blowing unit into the sheet processing apparatus. It is provided with a ventilation duct.
[Selection] Figure 5

Description

  The present invention relates to processing of a temporarily held sheet during sheet processing such as stacking processing, binding processing, punching processing, and the like of sheets formed and ejected on a sheet surface by an image forming apparatus main body such as a copier or LBP. The present invention also relates to an image forming apparatus including a sheet processing apparatus improved so that the held sheet can be effectively cooled.

  2. Description of the Related Art In recent years, sheet processing apparatuses such as a sorter and a finisher that sort image-formed sheets have been developed as options for image forming apparatus bodies such as electrophotographic copying machines and laser beam printers. This type of sheet processing apparatus performs at least one process such as a sort process, a binding process, an alignment process, a punching process, a bookbinding process, and a folding process on a sheet.

  In a sheet processing apparatus provided with a stapler that staples staples, a sheet transported into the main body of the sheet processing apparatus passes through a transport path formed inside the main body and is stacked on a post-processing tray to perform a binding operation. It has become.

  A sheet processing apparatus that binds a bundle of sheets stacks sheets in a bundle on a post-processing tray and moves a stapler as a binding unit to perform one-point binding or multi-point binding (usually two-point binding). It is like that. While the binding operation is being performed, sheets for the next job cannot be stacked on the post-processing tray. For this reason, it is necessary to leave an interval between sheets between job units in which the binding operation is performed.

  However, productivity (productivity) falls when the space | interval of sheets is opened. That is, the number of sheets processed per unit time is reduced. As a sheet processing apparatus for preventing such a decrease in productivity, there is a sheet processing apparatus shown in FIG. 20 (see, for example, Patent Document 1).

  A conventional sheet processing apparatus 10 shown in FIG. 20 wraps a sheet around a rotating buffer roller 13 in the conveyance path 12 in the middle of conveying the sheet to the post-processing tray 11, and conveys the sheet to the post-processing tray 11. A buffer roller path 14 for waiting is provided. Further, when the sheet processing apparatus 10 processes a sheet stacked on the post-processing tray 11, the sheet processing apparatus 10 processes the stapler and the like after aligning the end of the sheet with a stopper. For this reason, the sheet processing apparatus 10 uses the upper roller 18a provided on the bracket 22 rotating around the shaft 21 and the lower roller 18a on the post-processing tray 11 after passing through the buffer roller path 14 or the straight path 20 and the lower roller 18a. The roller 18b was sandwiched between the rollers 18b and brought into contact with the stopper by the rotation of the swing roller pair 18. The processed sheet is discharged and stacked on the stack tray 23 by the reverse rotation of the upper roller 18a and the lower roller 18b.

  As described above, when a sheet is processed by a stapler or the like, the conventional sheet discharge apparatus performs reciprocal conveyance in which the sheet is once conveyed to the right and then conveyed to the left and discharged in FIG. .

  With such a configuration, the conventional sheet processing apparatus 10 stores the sheet conveyed from the sheet discharge roller pair 17 in the image forming apparatus main body 16 of the image forming apparatus 15 in the buffer roller path 14 and stores the preceding sheet. The bundle, for example, finishes the binding operation on the post-processing tray 11 and is rotated and discharged from the post-processing tray 11 with the upper roller 18a and the lower roller 18b sandwiching the swing roller pair 18, and then stored in the buffer roller 13. By transporting the sheet bundle that has been transported to the post-processing tray 11, a decrease in productivity is prevented without increasing the transport interval between sheets during the binding operation.

JP 9-48545 A

  However, along with the recent increase in the speed of image forming apparatuses, the sheet sent from the image forming apparatus main body to the sheet processing apparatus becomes hot, the sheets held in the buffer roller path 14 stick to each other, causing a paper jam, There was a problem of causing defects.

  Further, since the buffer roller path 14 is a curved path, there has been a problem that the apparatus becomes large and expensive in order to effectively cool the entire held sheet.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus including a sheet processing apparatus that can effectively cool a held sheet without increasing the size of the apparatus and can reduce the cost.

  In order to solve the above-described problems, a typical configuration of an image forming apparatus according to the present invention is directed to an image forming unit that forms an image on a sheet and a sheet discharge unit that discharges the sheet on which the image is formed. An image forming apparatus comprising: an image forming apparatus main body having an air blowing unit for exhausting; and a sheet processing apparatus for receiving and transporting a sheet discharged from the image forming apparatus main body. It is characterized by having an air duct to be introduced into the.

  The image forming apparatus of the present invention employs a configuration in which a blowing unit is provided in the image forming apparatus body, a part of the conveyance guide in the sheet processing apparatus is used as a blowing duct, and air sent from the image forming apparatus body is taken in by the blowing duct. Accordingly, the sheet cooling mechanism can be provided in a small size and at a low cost without having a blower in the sheet processing device, and the sheet processing device can be reduced in size and cost.

  Further, by having a function of temporarily holding a plurality of sheets or a single sheet in the sheet processing apparatus, the sheets can be rapidly cooled during the temporary holding, and sticking between the sheets can be prevented. .

  Further, by having a function of temporarily holding a sheet, it is possible to prevent a paper jam in the sheet processing apparatus and stably provide a high-quality image without sacrificing the productivity of the image forming apparatus. it can.

[First embodiment]
A first embodiment of an image forming apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of the image forming apparatus. The image forming apparatus 100 includes an image forming apparatus main body 101 such as a copying machine, a facsimile machine, a printer, and a complex machine thereof, and a sheet processing apparatus 119 such as a finisher provided in the image forming apparatus main body 101.

  It should be noted that the dimensions, numerical values, materials, shapes, relative arrangements, and the like of the component parts described in this embodiment are intended to limit the scope of the present invention only to those unless otherwise specified. It is not a thing.

  In the description of the present embodiment, an example will be described in which the sheet processing apparatus is an optional apparatus configured to be detachable from the image forming apparatus main body as an independent apparatus. However, the present invention is also applied to an image forming apparatus in which the sheet processing apparatus is provided integrally with the main body of the image forming apparatus.

(Image forming device main unit)
A document feeder 102 is mounted on the upper part of the image forming apparatus main body 101. The document D is placed on the document placing unit 103 by the user, and sequentially separated one by one by the feeding unit 104 and supplied to the registration roller pair 105. Subsequently, the document D is temporarily stopped by the registration roller pair 105, a loop is formed, and skew is corrected. Thereafter, the document D passes through the introduction path 106 and passes through the reading position 108, whereby the image formed on the surface of the document is read. The document D that has passed the reading position 108 passes through a discharge path 107 and is discharged onto a discharge tray 109.

  When reading both the front and back sides of a document, first, the document D passes through the reading position 108 as described above, whereby an image on one side of the document is read. Thereafter, the document D passes through the discharge path 107, is conveyed in a switchback manner by the reverse roller pair 110, and is sent again to the registration roller pair 105 in a state of being reversed.

  Then, in the same manner as when the image on one side is read, the skew of the original D is corrected by the registration roller pair 105, and the image on the other side is read at the reading position 108 through the introduction path 106. It is done. Then, the document D passes through the discharge path 107 and is discharged to the discharge tray 109.

  On the other hand, the image of the original passing through the reading position 108 is irradiated with light from the illumination system 111. The reflected light reflected from the document is guided by the mirror 112 to the optical element 113 (CCD or other element) and obtained as image data. Then, a laser beam based on the image data is applied to, for example, the photosensitive drum 114a as an image forming unit to form a latent image. Although not shown, the mirror 112 may be configured to directly irradiate the photosensitive drums 114a, 114b, 114c, and 114d with reflected light to form a latent image.

  The latent images formed on the photosensitive drums 114a, 114b, 114c, and 114d are further formed into toner images by toner supplied from a toner supply device (not shown). Sheets that are recording media such as paper or plastic film are stacked on the cassette 115. The sheet is sent out from the cassette 115 according to the recording signal, and enters between the photosensitive drums 114a, 114b, 114c, and 114d and the transfer units 116a, 116b, 116c, and 116d. The toner images on the photosensitive drums 114a, 114b, 114c, and 114d are sequentially transferred onto the sheet by the transfer units 116a, 116b, 116c, and 116d. While the toner image is transferred to the sheet, the toner image is fixed by heating and pressing the fixing device 117 while passing through the fixing device 117.

  When images are formed on both sides of the sheet, the sheet on which the image is fixed on one side by the fixing device 117 passes through the double-sided path 118 provided on the downstream side of the fixing device 117 and is again transferred to the photosensitive drums 114a to 114d. The toner images are transferred to the back surfaces of the toner containers 116a to 116d. Then, the toner image is fixed by the fixing device 117 and discharged to the outside (sheet processing device 119 side).

  FIG. 2 is a control block diagram of the image forming apparatus 100. The image forming apparatus 100 is controlled by a CPU circuit 200. In the CPU circuit 200, there are provided a ROM 202 that stores the sequence of each part, that is, a control procedure, and a RAM 203 that temporarily stores various information as necessary. The document feeder controller 204 controls the document feeding operation of the document feeder 102. The image reader control unit 205 controls the illumination system 111 and the like to control reading of a document. The image signal control 206 receives the reading information of the image reader control unit 205 or the image information sent from the external computer 207 via the external I / F 208, processes the information, and processes the information to the printer control unit 209. The processing signal is sent to. The printer control unit 209 controls the photosensitive drums 104a to 104d and the like based on the image processing signal from the image signal control unit 206 so that an image can be formed on the sheet.

  The operation unit 210 can input sheet size information when the user uses the image forming apparatus 100, what kind of processing is performed on the sheet, for example, information for performing stapling processing, and the like. Information such as operation states of the image forming apparatus main body 101 and the sheet processing apparatus 119 can be displayed. The finisher control unit 211 controls the operation in the finisher (sheet processing apparatus 119). The FAX control unit 212 controls the copier so that the copier (image forming apparatus) 100 can be used as a fax machine, and can exchange signals with other fax machines.

(Sheet processing equipment)
FIG. 3 is a longitudinal sectional view of the sheet processing apparatus. FIG. 4 is a longitudinal sectional view showing each drive system.

  The sheet processing apparatus 119 has a function of binding a sheet bundle, a stapler 132 that binds near the edge of the sheet bundle, a stapler 138 that binds the center of the sheet bundle, and a sheet bundle bound by the stapler 138. A folding unit 139 or the like that folds the binding position portion to form a sheet bundle into a booklet is provided.

  The sheet processing apparatus 119 receives a sheet image formed by the image forming apparatus main body 101 and discharged from the discharge guide 165 by the receiving roller pair 137 and conveys the sheet to the buffer unit 140 which is a sheet holding unit through the reception guide 122.

  The buffer unit 140 is provided in the sheet processing apparatus 119 and accumulates (buffers) a plurality of sheets in a straight state when the stapler 132 is operated. Since the buffer unit 140 is configured to store a plurality of sheets in a straight state, the buffer unit 140 can be flattened unlike a conventional mechanism having a buffer roller, for example, to process sheets. The device 119 can be reduced in size and weight. Furthermore, since the sheets can be stored in a straight state, unlike the buffer roller, the sheets are not rounded, so that the sheets can be handled more easily, and the sheet processing time of the sheet processing apparatus can be reduced accordingly. can do.

  The sheet processing apparatus 119 is controlled by a finisher control unit 211 shown in FIG. In the CPU 221 of the finisher control unit 211, a ROM 222 storing a control sequence (sequence) of the sheet processing apparatus 119 that operates based on an instruction from the CPU circuit 200 of the image forming apparatus main body 101, and the sheet processing apparatus 119. A RAM 223 and the like for storing information necessary for controlling each time are provided. Further, a paper surface detection sensor 224 that operates based on an operation of a paper surface detection lever 133 described later is connected to the finisher control unit 211.

  The CPU 221 controls to raise and lower the stack tray 128 based on the sheet detection signal of the paper surface detection sensor 224. The finisher control unit 211 includes an inlet conveyance motor M2 that rotates the inlet roller pair 121, the buffer roller 124, and the first discharge roller pair 126, a bundle motor M3 that rotates the swing roller pair 127 and the return roller 130, and a bundle Based on the above sequence, the operation of the lower bundle clutch CL and the like for transmitting or cutting off the rotation of the take-out motor M3 to the lower roller 127b is controlled. Note that the CPU circuit 200 and the finisher control unit 211 in FIG. 2 may be integrated.

  In the lower bundle clutch CL shown in FIG. 4, a lower roller 127b and a return roller 130, which will be described later, are rotated by a common bundle motor M3, so that the lower roller 127b and the return roller 130 convey a sheet or a sheet bundle. In order to absorb the difference in speed, there is a risk of slipping or a difference in sheet conveyance speed between both rollers, which may cause wrinkles or damage to the sheet or sheet bundle. Is provided.

(Description of buffer operation)
Narrowing the conveyance interval between sheets is a very effective means for improving productivity. When a sheet bundle is being processed by the sheet processing apparatus, if the sheet is continuously fed and the sheets are continuously fed, the subsequent sheets are stored (buffered) only during the binding process. The buffer operation that is the operation will be described.

  The sheet processing apparatus 119 uses the buffer operation command of the finisher control unit 211 when the CPU circuit 200 of the image forming apparatus body 101 determines that the interval between sheets sent from the image forming apparatus body 101 is shorter than the sheet binding processing time. Based on this, a buffer operation is performed. In this case, the buffer roller 124 is lowered by the buffer roller separation plunger SL1 (see FIG. 4) and is in contact with the lower conveyance guide plate 123b.

  8A and 8B, it is assumed that the sheet bundle P is stacked on the processing tray 129. It is assumed that the sheet bundle P is subjected to the binding process by the stapler 132 (see FIGS. 3 and 4).

  As shown in FIG. 8A, when the first sheet P1 of the next sheet bundle is fed while the stapling process is being performed on the sheet bundle P stacked on the processing tray 129, The sheet P1 is fed to the buffer roller 124 by the inlet roller pair 121. The buffer roller 124 is rotated by an inlet conveyance motor M2 (see FIG. 4) to convey the sheet P1 downstream. At this time, the upper first discharge roller pair 126a of the first discharge roller pair 126 is separated from the lower first discharge roller pair 126b by the first discharge roller separation plunger SL2 (see FIG. 4).

  The first discharge roller separation plunger SL2 is not shown in FIG. 4 because it appears to overlap the buffer roller separation plunger SL1 in FIG. The upper roller 127a of the swing roller pair 127 is also separated from the lower roller 127b by a plunger (not shown).

  As shown in FIG. 8B, when the rear end of the sheet P1 reaches the switchback point SP, the sheet bundle P is returned to the upstream side by the reverse rotation of the buffer roller 124 as shown in FIG. 9A. It is. At substantially the same time, the rear end pressing member 135 is separated from the lower conveyance guide plate 123b, and the rear end receiving portion 136 is opened. The switchback point SP is reached after a predetermined time after the inlet sensor S1 disposed in the vicinity of the downstream side of the inlet roller pair 121 shown in FIG. It can be detected by the rotational speed of the roller 124 or the like.

  The upstream end side of the sheet P1 after the downstream end of the sheet is detected is received by the trailing end receiving portion 136 as shown in FIG. 9A. Thereafter, as shown in FIG. 9B, the rear end presser 135 returns to the original position and presses the sheet P1 against the lower conveyance guide plate 123b by the friction member 141 provided on the rear end presser 135.

  Thereafter, as shown in FIG. 10A, the second sheet P2 is fed. The second sheet P2 is conveyed by the entrance roller pair 121. At this time, the sheet P2 passes over the rear end press 135. Thereafter, the sheet P2 is also conveyed by the buffer roller 124 as shown in FIG.

  At this time, the first sheet P1 is pressed against the lower conveyance guide plate 123b together with the second sheet P2 by the buffer roller 124, and follows the second sheet P2 conveyed to the downstream side. Try to move. However, since the first sheet P1 is pressed against the lower transport guide plate 123b by the friction member 141 provided on the rear end press 135, it does not move.

  Similarly to the first sheet P1, the second sheet P2 is returned to the upstream side as shown in FIGS. 11 and 12 when the rear end reaches the switchback point SP. Then, the second sheet P2 is pressed against the lower conveyance guide plate 123b by the friction member 141 of the trailing edge press 135 so as to overlap the first sheet P1.

  Thereafter, as shown in FIG. 13A, when the third sheet P3 is fed and the rear end of the sheet P3 passes through the inlet roller pair 121, as shown in FIG. The first discharge roller pair 126a sandwiches the first to third sheets P1 to P3 with the lower first discharge roller pair 126b. At this time, the third sheet P3 slightly protrudes further downstream than the first and second sheets P1 and P2.

  At this time, since the binding process for the sheet bundle on the processing tray 129 has been completed, the trailing edge assist 134 moves along the processing tray 129 as shown in FIG. Push up the rear edge. As a result, the downstream end Pa of the sheet bundle P protrudes by a length L further downstream than the downstream ends P1a and P2b of the first and second sheets P1 and P2.

  Then, as shown in FIG. 14B, the upper roller 127a is also lowered, and the three sheets P1, P2, P3 and the sheet bundle P are sandwiched by the lower roller 127b. Along with this, the rear end press 135 is separated from the second sheet P2, and the first sheet P1 and the second sheet P2 are released.

  Thereafter, the three sheets P1, P2, P3 and the sheet bundle P are conveyed while being sandwiched between the swing roller pair 127. 15A and 15B, when the sheet bundle P is discharged to the stack tray 128, the rear ends of the first sheet P1 and the second sheet P2 are The upstream side portion of the three sheets is received by the processing tray 129 after coming out of the first discharge roller pair 126.

  In FIG. 15B, the first discharge roller pair 126, the swing roller pair 127, and the rear end assist 134 have the same start time (T1) and start speed (132 mm / sec), and the same acceleration end speed (500 mm / sec). ) At the same time (T2), the first discharge roller pair 126, the swing roller pair 127, and the rear end assist 134 apply a tensile force and a compressive force to the sheet bundle P and the three sheets P1 to P3. The sheet bundle P can be discharged without any addition.

  However, if there is a difference in the starting speed, as shown in S107 of FIG. 7, if a time difference of ΔT is provided and each is started, the pulling force is applied to the sheet bundle P or the three sheets P1 to P3. The sheet bundle P can be discharged without applying a compression force. Further, the rubbing marks of the rollers by the first discharge roller pair 126 and the swing roller pair 127 are not attached to the sheet, and the quality of the sheet bundle P and the image quality of the sheet bundle P are not deteriorated.

  As shown in FIGS. 16A and 16B, the three sheets P1 to P3 are transported down on the processing tray 129 by the swing roller pair 127 and the return roller 130 and received by the stopper 131. It is done. During this time, the stack tray 128 is once lowered to lower the upper surface of the sheet bundle P below the paper surface detection lever 133, and then rises again, when the paper surface detection lever 133 is operated by the upper surface of the sheet bundle P. , Stop climbing. As a result, the upper surface of the sheet bundle P on the stack tray 128 can be held at a predetermined height. Thereafter, the sheets P1 to P3 are sequentially stacked on the processing tray 129 without being accumulated on the lower conveyance guide plate 123b, and are bound when a predetermined number of sheets are reached. During this binding operation, the first three sheets of the subsequent sheet bundle are collected on the lower conveyance guide plate 123b.

  In the above description, three sheets are stored on the lower transport guide plate 123b. However, the number of sheets (buffer sheets) stored is the length of the sheet, the binding time, and the sheet transport. Since it varies depending on the speed and the like, it is not limited to three sheets, but may be one sheet, two sheets, or three or more sheets.

  As described above, in FIG. 14A, the sheet processing apparatus 119 moves the downstream end Pa of the sheet bundle P to the downstream side of the downstream ends P1a and P2b of the first and second sheets P1 and P2. A length L is projected. This is due to the following reason.

  If the protruding length of the downstream end Pa is L1 shorter than the length L as shown in FIG. 17, the protruding length of the downstream end Pa is also L1. For this reason, after the pair of swing rollers 127 discharges the sheet bundle P to the stack tray 128, the length of gripping the three buffer sheets P1 to P3 is shortened, and the three buffer sheets P1 to P3 are not gripped. In some cases, the sheet cannot be reliably fed into the processing tray 129. Therefore, the sheet bundle P protrudes from the buffer sheet by a length L so that the swing roller pair 127 can securely grasp the buffer sheets P1 to P3 and send them to the processing tray 129.

  In addition, when the protruding length is short, the contact area between the buffer sheets P1 to P3 and the sheet bundle P is widened, and the sheet bundle P comes into close contact with the buffer sheets P1 to P3 and slows down to the stack tray 128. It tends to be. In such a case, when the swing roller pair 127 is reversed and the buffer sheets P1 to P3 are fed into the processing tray 129, the sheet bundle P enters the swing roller pair 127 while being in close contact with the buffer sheets P1 to P3. As a result, the sheet bundle P may be damaged or cause jamming. Therefore, in order to improve the separation between the sheet bundle P and the buffer sheets P1 to P3, the sheet bundle P is projected by the length L with respect to the buffer sheets P1 to P3.

  In addition, the sheet processing apparatus 119 is configured such that the trailing edge assist 134 pushes the trailing edge of the sheet bundle P. In this way, when the sheet bundle P is conveyed by pushing the rear end of the sheet bundle P with the rear end assist 134, the surface of the sheet bundle P is different from the case where the sheet bundle is discharged by rotating the roller against the surface of the sheet bundle. It can be reliably transported without scratching.

  That is, as shown in FIG. 18, when the sheet bundle P is discharged only by the swing roller pair 127, the conveyance amount of the sheet depends on a difference in friction between the upper roller 127a and the lower roller 127b with respect to the sheet, a difference in rotational speed, and the like. However, the upper sheet and the lower sheet may be misaligned. In such a case, the swing roller pair 127 may slide and rotate with respect to the sheet and damage the sheet. Further, the entire sheet bundle is discharged while being twisted, so that the sheet bundle P cannot be discharged smoothly, and processing takes time. Further, when the entire sheet bundle is twisted, the sheet may be torn at the bound portion and the sheet bundle P may not be used.

  Further, such a phenomenon is likely to occur when the sheet bundle P is reliably discharged and used, and the pinching force of the swing roller pair 127 against the sheet bundle P is increased. Conversely, the sheet bundle P that weakens the clamping pressure cannot be reliably conveyed. Therefore, it is difficult to set the clamping pressure of the swing roller pair 127.

  Therefore, the sheet processing apparatus 119 is configured to discharge the sheet bundle not only by the swing roller pair 127 but also by the rear end assist 134. The sheet bundle P can be discharged smoothly and promptly without damaging the sheet or the sheet bundle P. Further, the sheet bundle P can be discharged without strictly managing the clamping pressure of the swing roller pair 127.

(Description of sheet cooling)
Next, a method for cooling a sheet discharged from the image forming apparatus main body 101 will be described. FIG. 5 is a longitudinal sectional view of the sheet processing apparatus buffer section and the sheet discharge section for explaining the flow of cooling air in the image forming apparatus.

  The sheet cooling fan 150 is a blowing unit provided in the image forming apparatus main body 101, takes in outside air into the image forming apparatus main body 101, and sends air into the discharge guide 165 through the duct 160 (arrow in FIG. 5). ). The discharge guide 165 plays a role of guiding the sheet discharged from the image forming apparatus main body 101 to the sheet processing apparatus 119 and simultaneously sending the wind from the duct 160 to the inlet guide portion 170 of the sheet processing apparatus 119.

  Further, the inlet guide portion 170 is a substantially sealed space, and functions as a blower duct that introduces the air exhausted from the image forming apparatus main body 101 and guides it to the buffer unit 140.

  As described above, the buffer unit 140 has a function of holding a plurality of sheets. Therefore, while buffering, as described above, the cooling air is sent to the buffer unit 140 to prevent the buffer sheets from sticking to each other, and at the same time, by cooling the sheets during processing, the stack tray It is possible to prevent the sheets from sticking to each other.

  As described above, it is possible to prevent a paper jam in the sheet processing apparatus and stably provide a high-quality image without sacrificing the productivity of the image forming apparatus. In addition, by cooling the sheet at the time of buffering, it is possible to effectively cool the sheet, and further, a part of the guide serves as a duct without having a blowing means in the sheet processing apparatus, A small and inexpensive sheet cooling system can be realized.

  The sheet processing apparatus according to the present embodiment has been described with respect to the case where the stapler 132 is provided with the buffer unit 140 that accumulates (buffers) a plurality of sheets in a straight state when the stapler 132 is operated. It is not a thing.

[Second Embodiment]
Next, a second embodiment of the image forming apparatus according to the present invention will be described with reference to the drawings. About the part which overlaps with said 1st embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  FIG. 19 is a cross-sectional view of the image forming apparatus according to the present embodiment. As shown in FIG. 19, in addition to the first embodiment, the image forming apparatus 100 in this embodiment includes a sheet punching device 180 between the image forming apparatus main body 101 and the sheet processing apparatus 119.

(Sheet punching device)
As shown in FIG. 20, the sheet punching device 180 includes an inlet guide portion 181, transmission sensor upper and lower 186a and 186b, punching portion 182, stop roller upper and lower 183a and 183b, stop conveyance guide upper and lower 184a and 184b, and a punch waste box 185. Is a unit.

  Next, operation during sheet punching will be described. As shown in FIG. 20, the sheet S 1 is discharged from the image forming apparatus main body 101 and sent to the punching device 180 through the discharge guide 165. The leading edge of the sheet S1 is detected by the upper transmission sensor 186a and the lower transmission sensor 186b.

  When the leading edge of the sheet S1 is detected, the perforation 182 is moved by a motor (not shown), the paper edge on the back side of the sheet S1 is detected by the upper and lower transmission sensors 186a and 186b, and the lateral registration position of the sheet S1 is confirmed. Lateral misregistration correction is performed by moving the perforation unit 182 to the perforation position.

  Thereafter, the rear end of the sheet S1 is detected by the upper and lower transmission sensors 186a and 186b (FIG. 21), and after a predetermined amount is fed so that the punching position from the rear end of the sheet becomes constant, the sheet is stopped by the pair of stop rollers 183a and 183b. S1 is stopped (FIG. 22). Thereafter, the sheet S1 is punched by the punching unit 182. The perforated waste is collected in a perforated waste box 185.

  By performing the punching process one by one by the above operation, it is possible to perform a highly accurate drilling process.

(Description of sheet cooling)
Next, a method for cooling a sheet discharged from the image forming apparatus main body 101 will be described. FIG. 23 is a longitudinal sectional view of the sheet processing apparatus, the sheet punching apparatus, and the sheet discharge unit.

  The sheet cooling fan 150 is provided in the image forming apparatus main body 101, takes outside air into the image forming apparatus main body 101, and sends air to the discharge guide 165 through the duct 160 (arrow in FIG. 23). The discharge guide 165 plays a role of guiding the sheet discharged from the copying machine 100 to the sheet punching device 180 and simultaneously sending the wind from the duct 160 to the inlet guide portion 181 of the sheet punching device.

  The inlet guide portion 181 is a substantially sealed space, and is a duct that guides the wind sent from the image forming apparatus main body 101 into the sheet punching apparatus.

  As described above, the sheet punching device 180 has a function of stopping and holding one sheet. Thus, while the sheet is stopped, the sheet can be rapidly cooled during sheet processing by sending the cooling air to the sheet punching device 180 as described above. As a result, it is possible to prevent the sheets from being stuck on the stack tray 128 during subsequent buffer processing.

  As described above, it is possible to prevent a paper jam in the sheet processing apparatus and stably provide a high-quality image without sacrificing the productivity of the image forming apparatus. In addition, the sheet can be effectively cooled by cooling the sheet at the time of stoppage. Further, since the part of the guide functions as a duct, the sheet processing apparatus does not have a blowing unit, and the sheet processing apparatus has no air blowing means. The cooling mechanism can be realized small and inexpensively.

  Although the sheet punching device 180 of the present embodiment has been described with respect to a case where one sheet is stopped in a straight state during punching, the present invention is not limited to this.

1 is a cross-sectional view of an image forming apparatus according to a first embodiment. 2 is a control block diagram of the image forming apparatus. FIG. It is a longitudinal cross-sectional view of a sheet processing apparatus. It is the longitudinal cross-sectional view which showed the drive system of the sheet processing apparatus. FIG. 6 is an explanatory diagram of a flow of cooling air in the image forming apparatus. It is a control block diagram of a sheet processing apparatus. FIG. 10 is a flowchart for explaining an operation when a sheet bundle is discharged in the sheet processing apparatus. It is a diagram for explaining the operation of the sheet processing apparatus when collecting sheets during sheet processing. FIG. 6A is a diagram illustrating a state where a first sheet has been fed into the sheet processing apparatus. (B) It is a figure of the state which received the 1st sheet | seat to the switchback point. FIG. 9 is a diagram for explaining the operation of the sheet processing apparatus when collecting sheets during sheet processing, and is a diagram for explaining the operation following FIG. 8. (A) It is a figure of the state which received the 1st sheet | seat with the rear-end receiving part. (B) It is a figure of the state which pressed down the 1st sheet | seat to the lower conveyance guide plate by the rear end pressing. FIG. 10 is a diagram for explaining the operation of the sheet processing apparatus when collecting sheets during sheet processing, and is a diagram for explaining the operation following FIG. 9. FIG. 6A is a diagram illustrating a state where a second sheet has been fed into the sheet processing apparatus. (B) It is a figure of the state in which the 2nd sheet | seat was further sent. FIG. 11 is a diagram for explaining the operation of the sheet processing apparatus when collecting sheets during sheet processing, and is a diagram for explaining the operation following FIG. (A) It is a figure of the state which received the 2nd sheet | seat to the switchback point. (B) It is a figure of the state which received the 2nd sheet | seat with the rear-end receiving part. FIG. 6 is a diagram for explaining the operation of the sheet processing apparatus when collecting sheets during sheet processing, and is a diagram showing a state in which the first sheet and the second sheet are stacked and pressed onto the lower conveyance guide plate by a rear end pressing. . FIG. 13 is a diagram for explaining the operation of the sheet processing apparatus when sheets are accumulated during sheet processing, and is a diagram for explaining the operation following FIG. (A) It is a figure of the state from which the 3rd sheet has been sent. (B) It is a figure of the state in which the 3rd sheet | seat was sent. FIG. 14 is a diagram for explaining the operation of the sheet processing apparatus when collecting sheets during sheet processing, and is a diagram for explaining the operation following FIG. (A) It is a figure of the state which begins to discharge | emit a sheet bundle from a processing tray to a stack tray. (B) It is a figure of the state which is conveying the sheet | seat bundle | flux in a discharge direction with a buffer sheet. FIG. 15 is a diagram for explaining the operation of the sheet processing apparatus when collecting sheets during sheet processing, and is a diagram for explaining the operation following FIG. (A) It is a figure of the state which discharged | emitted the sheet bundle from the processing tray to the stack tray. (B) It is a figure of the state which has sent the buffer sheet | seat into the process tray. FIG. 16 is a diagram for explaining the operation of the sheet processing apparatus when collecting sheets during sheet processing, and is a diagram for explaining the operation following FIG. (A) It is a figure of the state which has sent the buffer sheet | seat into the process tray. (B) It is a figure of the state which has further sent the buffer sheet | seat into the processing tray. It is a figure for operation | movement explanation when the protrusion length of the downstream end of the sheet bundle from the downstream end part of a buffer sheet is short. FIG. 4 is a perspective view of a sheet processing apparatus that discharges a sheet bundle only with a swing roller pair. It is a front schematic sectional drawing of the image forming apparatus of 2nd embodiment of this invention. It is a figure for demonstrating the sheet punching operation | movement of the sheet punching apparatus concerning 2nd embodiment of this invention. It is a figure for demonstrating the sheet punching operation | movement of the sheet punching apparatus concerning 2nd embodiment of this invention. It is a figure for demonstrating the sheet punching operation | movement of the sheet punching apparatus concerning 2nd embodiment of this invention. It is explanatory drawing of the flow of the cooling air of the image forming apparatus of 2nd embodiment. It is a front schematic sectional drawing of the conventional sheet processing treatment.

Explanation of symbols

100 ... Image forming apparatus
101 ... Image forming apparatus main body
121… Inlet roller pair
122… Receiving Guide
124… Buffer roller
137… Receiving roller pair
138… Stapler
139… Folding unit
140… Buffer unit
150… Seat cooling fan
160… Duct 160
165… discharge guide
170… Entrance guide
180 ... sheet punching device
181… Entrance guide
182… perforated part
183… Stopping roller up and down
184… Stop conveyance guide up and down
185 ... Perforated waste bin
186… Upper and lower transmission sensor

Claims (5)

An image forming apparatus main body having an image forming means for forming an image on the sheet, and an air blowing means for exhausting air toward the outside in the sheet discharge portion for discharging the sheet on which the image is formed;
In an image forming apparatus comprising: a sheet processing apparatus that receives and conveys a sheet discharged from the image forming apparatus main body,
An image forming apparatus comprising a blower duct for introducing exhaust air from the blower into the sheet processing apparatus. The image forming apparatus according to claim 1, wherein the sheet processing apparatus includes a sheet post-processing unit that post-processes the sheet. The image forming apparatus according to claim 1, wherein the sheet processing apparatus includes a sheet holding unit capable of temporarily holding a plurality of sheets. The image forming apparatus according to claim 1, wherein the sheet processing apparatus includes a sheet holding unit capable of temporarily holding one sheet. The image forming apparatus according to claim 1, wherein a sheet conveyance guide of the sheet processing apparatus forms the air duct.

Images