JP2007241111A - Sheet ejecting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet ejecting device combining cooling performance with stacking ability without making a cooling device large and complicated. <P>SOLUTION: The sheet ejecting device 200 which ejects and stacks a sheet S on which an image has been formed to a stacking part 3 has: a cooling fan 6 sending cooling air A for cooling the sheet S stacked on the stacking part 3 from the upper surface side of the sheet S; and an ejection auxiliary means 51 guiding the cooling air A jetted by the cooling fan 6 to the upper surface of the sheet S stacked on the stacking part 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sheet discharging apparatus that discharges a sheet on which an image is formed on a sheet material.

  Also in the prior art, cooling air is guided near the discharge portion to cool the discharge sheet. This is because, for example, when continuous double-sided recording and discharging are performed, the stacked sheets are adhered to each other due to remelting of toner and the like due to their own heat.

  However, in the case of a high-speed machine that requires a high cooling effect, cooling from only one side causes rounding or the like at the stacking section, and the stackability of the discharged sheets becomes unstable. Therefore, as disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 09-034321), air is blown from the upper and lower surfaces of the discharge sheet to ensure the cooling performance and stabilize the sheet discharge posture, so that both cooling performance and stackability are compatible. I am trying.

JP 09-034321 A

  However, in the technique described in Patent Document 1, since cooling is performed from the upper surface and the lower surface of the discharge sheet, the cooling device including the fan and the duct becomes large and complicated. In the case of an image forming apparatus having a stacking unit between a printer device and a reader unit in recent years, it may be impossible to mount such a large cooling device due to the height of the device.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet discharging apparatus that can achieve both cooling performance and stackability without increasing the size and complexity of the cooling apparatus.

  In order to solve the above-described problems, a typical configuration of the sheet discharge apparatus according to the present invention is to cool a sheet stacked on the stacking unit in an image forming apparatus that discharges and stacks a sheet on which an image is formed on the stacking unit. Cooling means for sending the cooling air from the upper surface side of the sheet; and discharge assisting means for guiding the cooling air ejected by the cooling means to the upper surface of the sheet stacked on the stacking section.

  According to the present invention, the cooling air is guided so as to maximize the cooling effect. As a result, the cooling effect can be obtained with a small amount of air, and both the cooling performance and the loadability can be achieved without increasing the size and complexity of the cooling device. Can be achieved.

[First embodiment]
A first embodiment of an image forming apparatus provided with a sheet discharging apparatus according to the present invention will be described with reference to the drawings.

(Configuration of image forming apparatus)
FIG. 7 is a configuration diagram of a digital image forming apparatus. As shown in FIG. 7, the image forming apparatus 100 includes a reader 1 and a printer 2. The image forming apparatus 100 has a so-called in-body discharge configuration in which an image-formed sheet is discharged between the reader 1 and the printer 2.

  The reader 1 reads image information of a document and processes it with a digital signal. The reader 1 includes a control panel (not shown), a platen cover 105, an image scanning mechanism 106, and a controller 107.

  The reader 1 operates the image forming apparatus 100 with a control panel. The reader 1 presses and holds the original set on the upper surface of the reader 1 with the platen cover 105, and scans the image of the original with the image scanning mechanism 106. The image information of the original obtained by scanning the image scanning mechanism 106 is processed by the controller 107 with a digital signal and transmitted to the printer 2.

  The printer 2 forms an image on the sheet S based on the image information transmitted from the reader 1. The printer 2 includes a writing device (laser scanner) 112, an image forming unit 113, a fixing device 114, a feeding unit 104, a manual feeding unit 117, and a sheet discharging device 200.

  The laser scanner 112 receives the digital signal input from the reader 1 and irradiates the photosensitive drum 113a with a laser beam to write an image. The image forming unit 113 develops the electrostatic latent image formed on the photoconductive drum 113a by writing the image with toner to form a toner image, and transfers the toner image to a sheet. The fixing device 114 fixes the transferred toner image.

  The feeding unit 104 is located below the printer 2. The feeding unit 104 includes a plurality of feeding cassettes 118a and feeding rollers 119a. The feeding roller 119a feeds the sheet S stored in the feeding cassette 18a.

  The manual feed unit 117 is located on the side surface of the printer 2. The manual feed unit 117 includes a manual feed tray 118 and a feed roller 119b that is a sheet feeding unit.

(Image Forming Operation of Image Forming Apparatus 100)
An image forming operation of the image forming apparatus 100 will be described. First, issue a printout signal from the computer or press the copy start button. Then, the sheet S is conveyed from the feeding unit 104 or the manual feeding unit 117 to the image forming unit 113. The sheet S conveyed to the image forming unit 113 is transferred with the toner image formed on the photosensitive drum 113a. The sheet S to which the toner image is transferred is heated and pressed by the fixing device 114 to fix the toner image. The sheet S on which the toner image is fixed is discharged out of the image forming apparatus 100 by the sheet discharge apparatus 200.

(Sheet discharge device 200)
Next, the sheet discharging apparatus 200 will be described with reference to FIGS.

  As shown in FIGS. 1 and 2, the sheet discharge device 200 includes a discharge roller 41, a discharge port 42, a cooling fan 6, and discharge auxiliary means (discharge auxiliary member) 51. The discharge roller 41 discharges the sheet S on which the toner image is fixed from the discharge port 42 and stacks it on the stacking unit 3. The cooling fan 6 sends cooling air A to the discharged sheet S, and cools the sheet S that has become hot due to image formation.

  The discharge assisting means 51 is a sheet-like member having a flat surface for guiding the cooling air A sent out from the cooling fan 6. One end of the discharge assisting means 51 is pivotally supported by a rotation shaft 52 provided at the upper part of the discharge port 42.

  Further, the discharge assisting means 51 functions as a full load detecting means, a scraping means, and a wind direction plate. The full load detecting means detects the full load of discharged sheets. The scraping means scrapes the discharge sheet. The wind direction plate changes the wind direction of the cooling air A discharged from the cooling fan 6.

  The discharge assisting unit 51 assists the discharge of the sheet by pressing the sheet discharged by the discharge roller on the lower surface toward the stacking unit 3. Further, when the number of sheet bundles stacked on the stacking unit 3 increases, the discharge assisting unit 51 acts to press the rear end side of the sheet bundle against the stacking unit 3 side. Further, the discharge assisting unit 51 detects the full load when the sheets S are stacked on the stacking unit 3 to a predetermined height. When the full load is detected, the sheet discharge is stopped. As a result, it is possible to prevent the sheet stacked on the stacking unit 3 from blocking the discharge port 42 and causing a jam.

  The discharge assisting means 51 is at the first position 51a (home position) when the sheet S is not discharged as shown in FIG. In this state, as shown in FIGS. 3 and 4, the cooling air A strikes the discharge assisting means 51 and is guided to the central portion Sa of the sheet S.

  Here, as shown in FIG. 4, the center in the transport direction of the sheet S is X, and the center in the sheet width direction orthogonal to the transport direction is Y. Then, since the central portion Sa of the sheet S is likely to accumulate heat, the central portion Sa where the X and Y of the sheet S intersect is a high temperature portion showing a high temperature in terms of temperature distribution.

  In this way, by sending the cooling air A intensively to the central portion Sa having a high temperature, the temperature of the entire sheet bundle discharged and stacked can be made uniform, and sticking between sheets can be suppressed.

  Note that the position of the center X varies depending on the length of the sheet S in the conveyance direction. For this reason, the angle of the cooling fan 6 is changed by driving means (not shown) according to the length of the sheet to be discharged. Note that the angle of the cooling fan 6 may be fixed so that the cooling air A hits the center X of the sheet most frequently used in double-sided recording (the sheet with the highest temperature).

  As described above, by efficiently cooling the high temperature portion Sa with a small air volume via the cooling auxiliary means 51a, sticking can be sufficiently suppressed even in a 50 CPM (copy per minute) class color copying machine.

  On the other hand, when the sheet S is discharged as shown in FIG. 2, the discharge assisting means 51 is pushed up by the discharged sheet S and rotates to the second position 51 b around the rotation shaft 52. . At this time, the sheet S is scraped off to the stacking unit 3 by the leading end of the discharge assisting means 51 to realize a stable stacking property.

  In the state where the sheet S is being discharged, the cooling air A hits the discharge assisting means 51, the air direction is changed to a direction substantially parallel to the upper surface of the stacking unit 3, and is discharged to the outside as it is. At this time, the high-temperature atmosphere confined in the loading unit 3 is discharged outside the apparatus. In this way, depending on whether or not the sheet is discharged, it is possible to repeat the cooling of the sheet and the discharge of the high temperature atmosphere confined in the stacking unit 3, and the cooling effect can be stabilized.

  Further, if the sheet S being discharged is strongly supplied with the cooling air A before landing on the stacking unit 3, the sheet S is curled up and stackability is impaired.

  On the other hand, in the present embodiment, the cooling air A is discharged outside the apparatus without hitting the sheet S during sheet discharge. For this reason, curling of sheets can be suppressed and stackability can be improved.

  Further, when the sheet S falls to the stacking unit 3, the discharge assisting unit 51 starts rotating, and the cooling air A comes into contact with the falling sheet S. However, as described above, the air A is actively guided to the central portion Sa of the sheet S, and the high temperature portion Sa is actively cooled. Therefore, the air volume of the cooling air A is suppressed from the conventional level while maintaining the cooling effect. Can do. Thereby, curling of sheets can be suppressed and stackability can be improved.

(Comparative example)
As shown in FIG. 6, a configuration in which the cooling fan 6 is raised and disposed at the position 6b and air is directly blown from the cooling fan 6b to the high temperature portion Sa is conceivable. However, in this case, it is necessary to move the reader 1 upward by the amount that the cooling fan 6 is raised (height h1), which increases the height of the apparatus.

  Further, a configuration in which the cooling fan 6 is arranged at a position 6c above the high temperature part Sa and air is blown directly from the cooling fan 6c directly below the high temperature part Sa is conceivable. However, in this case, the take-out height of the stacked sheets 7a is narrowed by the thickness (h2-h3) of the cooling fan 6c. For this reason, the take-out property of the sheet is deteriorated.

(effect)
On the other hand, in the configuration of the present embodiment, the cooling fan 6 is provided at a position slightly protruding from the front surface of the apparatus (discharge port 42) toward the sheet take-out position P. Then, discharge assisting means 51 for guiding the cooling air A ejected by the cooling fan 6 to the upper surface of the sheets S stacked on the stacking unit 3 is provided. Thereby, the height of the apparatus can be suppressed, and the sheet take-out property can be improved.

  The cooling fan 6 sends cooling air A in the sheet take-out direction. For this reason, the discharged sheet S is sent out by the cooling air A in the sheet take-out direction. Accordingly, the sheets are stacked at a position close to the sheet take-out position P, and the take-out property of the sheets can be improved.

  In addition, the cooling air A is guided so as to maximize the cooling effect, and as a result, the cooling effect can be obtained with a small amount of air, and both cooling performance and loadability can be achieved without increasing the size and complexity of the cooling device. .

[Second Embodiment]
Next, a second embodiment of the image forming apparatus according to the present invention will be described with reference to the drawings. FIG. 8 is a top view of the stacking unit according to the present embodiment. About the part which overlaps with said 1st embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  Also, as shown in FIG. 8, two discharge assisting means 51 are provided on both sides in the sheet width direction. Accordingly, a space W in which the discharge assisting means 51 does not exist is formed at the center in the sheet width direction.

  As a result, the cooling air A is cooled from the leading edge to the trailing edge of the sheet S even during sheet discharge, the cooling time becomes longer, and the cooling effect can be further enhanced. The width of the space W is such that the sheet S is not rounded.

It is a longitudinal cross-sectional view of the sheet discharging apparatus in a state where the sheet according to the first embodiment is not discharged. It is a longitudinal cross-sectional view of the sheet discharging apparatus in a state where the sheet is discharged. It is a longitudinal cross-sectional view of a sheet discharging apparatus showing a relationship between cooling air and a sheet in a state where the sheet is not discharged. It is a top view of a loading unit. It is a longitudinal cross-sectional view of a sheet discharging apparatus showing a relationship between cooling air and a sheet in a state where the sheet is discharged. It is a longitudinal cross-sectional view of the sheet discharge apparatus of a comparative example. 1 is a configuration diagram of an image forming apparatus. It is a top view of the stacking unit according to the second embodiment.

Explanation of symbols

A ... Cooling air, P ... Sheet take-out position, S ... Sheet, Sa ... Center part, W ... Space, X, Y ... Center, h1-h3 ... Height, 1 ... Reader, 2 ... Printer, 3 ... Stacking part, DESCRIPTION OF SYMBOLS 6 ... Cooling fan (cooling means), 41 ... discharge roller, 42 ... discharge port, 51 ... discharge auxiliary means, 51a ... first position, 51b ... second position, 52 ... rotating shaft, 100 ... image forming apparatus DESCRIPTION OF SYMBOLS 104 ... Feeding part 105 ... Platen cover 106 ... Image scanning mechanism 107 ... Controller 112 ... Laser scanner 113 ... Image forming part 113a ... Photosensitive drum 114 ... Fixing device 117 ... Manual feeding part 118 ... Bypass tray, 118a ... Feed cassette, 119a, 119b ... Feed roller, 200 ... Sheet discharge device

Claims (7)

In a sheet discharge device that discharges and stacks a sheet on which an image is formed to a stacking unit,
Cooling means for sending cooling air for cooling the sheets stacked on the stacking unit from the upper surface side of the sheets;
Discharge assisting means for guiding the cooling air ejected by the cooling means to the upper surface of the sheets stacked on the stacking unit.
The discharge assisting means includes a first position for guiding the cooling air to the central portion of the sheet when the sheet is not discharged, and a second position for guiding the cooling air to the outside as it is when the sheet is discharged. The sheet discharging apparatus according to claim 1, wherein the sheet discharging apparatus can be rotated to the position of the sheet.
The sheet discharge apparatus according to claim 1, wherein the discharge assisting unit is formed of a sheet-like member having a flat surface for guiding cooling air.
The sheet discharge according to any one of claims 1 to 3, wherein the discharge auxiliary means is provided only on both sides in the sheet width direction so that the cooling air is not guided at the center in the sheet width direction. apparatus.
The sheet discharging apparatus according to claim 1, wherein the cooling unit sends cooling air in a sheet take-out direction.
A discharge roller for discharging the sheet to the stacking section through a discharge port;
The discharge assisting member is provided so as to be rotatable around a rotation shaft provided at an upper part of the discharge port,
The cooling air ejected by the cooling means is ejected from above the discharge assisting member,
The discharge assisting unit presses the sheet discharged by the discharge roller toward the stacking unit,
6. The discharge assisting unit guides cooling air ejected by the cooling unit on a surface opposite to the stacking unit to an upper surface of a sheet stacked on the stacking unit. The sheet discharging apparatus according to the item.
The discharge assisting means is pushed and rotated by the sheet being discharged by the discharge roller,
In a state where the sheet is not discharged by the discharge roller, the discharge assisting unit guides the cooling air ejected by the cooling unit on the surface opposite to the stacking unit to the upper surface of the sheet stacked on the stacking unit. In the state where the sheet is being discharged by the discharge roller, the discharge assisting means is rotated by being pushed by the sheet, and the cooling air ejected by the cooling means on the opposite surface is provided. The sheet discharging apparatus according to claim 1, wherein the sheet discharging apparatus is located at a position leading to the outside.

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