JP2017198915A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve cooling efficiency for recording paper subjected to fixing processing.SOLUTION: An image forming apparatus comprises: a fixing part 13 that fixes a toner image to recording paper; a recording paper ejection port 157 that is on the downstream side of the fixing part 13 for ejecting the recording paper; an ejection tray 151 that receives the recording paper ejected from the recording paper ejection port 157 by an ejection roller pair 181; and a cooling part including a cooling fan and a cooling air exhaust port 53 that exhausts a cooling air from the cooling fan. The cooling air exhaust port 53 is arranged downward above the recording paper ejection port 157 on the downstream side in a conveyance direction; a plurality of first ribs 154 are provided on a loading surface 152 of the ejection tray 151, extend in the recording paper conveyance direction, and arranged side by side with an interval in a width direction orthogonal to the conveyance direction; the height of the first ribs 154 is set to a height to the extent that the cooling air exhausted from the cooling air exhaust port 53 flows into a space formed by the recording paper loaded on the first ribs 154 and the loading surface 152.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an image forming apparatus, and more particularly to a technique for cooling a recording sheet on which a toner image is formed.

  Some image forming apparatuses fix a toner image on a recording sheet by thermocompression bonding, and the recording sheet subjected to the fixing process is discharged to a discharge tray. When the recording paper is continuously discharged, the recording paper is stacked on the discharge tray, and the toner image formed on the recording paper may adhere to other recording paper. In order to prevent this, various proposals have been made to put cooling air from a cooling fan onto a recording sheet that has been subjected to a fixing process, and it has been put to practical use (for example, see Patent Document 1 below).

JP 2008-268643 A

  In cooling the recording paper subjected to the fixing process, it is effective to blow cooling air directly onto the recording paper discharged to the discharge tray. Further, as a configuration for realizing this, a configuration in which a cooling air discharge port for discharging cooling air is disposed above the recording paper discharge port from which the recording paper is discharged can be considered. However, there is a case in which the recording paper is not efficiently cooled only by applying cooling air from above to the discharged recording paper, and further improvement is required.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to increase the cooling efficiency with respect to the recording paper discharged after fixing as compared with the conventional one.

  An image forming apparatus according to an aspect of the present invention includes a fixing unit that fixes a toner image on a recording sheet, and a recording sheet discharge port that discharges the recording sheet on the downstream side in the conveyance direction of the recording sheet with respect to the fixing unit. A pair of discharge rollers provided at the recording paper discharge port; a discharge tray on which the recording paper discharged from the recording paper discharge port by the discharge roller pair is placed on a placement surface; a cooling fan; And a cooling unit having a cooling air discharge port for discharging cooling air from the cooling fan, the cooling air discharge port being downstream in the transport direction of the recording paper discharge port and above the recording paper discharge port At a position where the cooling air is discharged in a downward direction, and the placement surface of the discharge tray has a plurality of first protrusions or first recesses extending in the transport direction of the recording paper. The plurality of first protrusions or Between the recording sheet placed on the first convex portion and the placement surface or between the recording paper placed on the placement surface and the first recess by the first recess. A gap through which the cooling air passes is formed.

  In the present invention, since the cooling air discharge port is disposed upward and downward on the downstream side in the conveyance direction of the recording paper discharge port, the cooling air is directly blown onto the recording paper on which the fixing process has been performed. Between the recording sheet placed on the first convex portion formed on the loading surface and the loading surface of the discharge tray (or formed on the loading surface and the recording sheet placed on the loading surface of the discharge tray). Since a gap through which the cooling air passes is formed between the first recess and the first recess, the cooling air discharged from the cooling air discharge port can flow into the gap. For this reason, in the present invention, the recording paper stocked in the discharge tray in a state of being placed on the first convex portion (or the placement surface on which the first concave portion is formed) is not only from above but also from below. Can also be cooled. Therefore, according to the present invention, the cooling efficiency with respect to the recording paper discharged after fixing can be improved as compared with the conventional case.

1 is a perspective view illustrating an appearance of an image forming apparatus according to a first embodiment of the present invention. It is an expansion perspective view which shows a cooling part and its peripheral part. 1 is a cross-sectional side view of an image forming apparatus. FIG. 3 is a cross-sectional side view showing a recording paper discharge port and its peripheral part. It is the expanded sectional side view which showed the discharge roller pair and its peripheral part. FIG. 9 is a cross-sectional side view showing a recording paper discharge port and its peripheral part in an image forming apparatus according to a second embodiment. FIG. 10 is a perspective view illustrating a state in which a recording sheet P is placed on a placement surface in an image forming apparatus according to a second embodiment. FIG. 10 is an explanatory diagram for explaining a direction in which cooling air flows in an image forming apparatus according to a second embodiment.

  Hereinafter, an image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing an appearance of the image forming apparatus according to the first embodiment of the present invention. The image forming apparatus 1 is a printer, and includes an apparatus main body 11 that accommodates an image forming unit 12 and the like to be described later. A discharge tray 151, a recording paper pressing member 158, and an upper cover 171.

  The operation unit 47 receives instructions such as an image forming operation execution instruction from the operator for various operations and processes that can be executed by the image forming apparatus 1, and the display unit 473 displays information indicating the state of the image forming apparatus 1. To do.

  The recording paper discharge port 157 is on the downstream side of the fixing unit 13 to be described later and discharges the recording paper. Above the recording paper discharge port 157, a plurality of recording paper pressing members 158 arranged at intervals in the width direction orthogonal to the horizontal direction with respect to the discharging direction are formed, and the curl correction of the discharged recording paper and the like are performed. Done.

  The recording paper discharged from the recording paper discharge port 157 is placed on the discharge tray 151. The discharge tray 151 extends downward from the front surface to the rear portion of the mounting surface 152 and the rear end of the mounting surface 152 in the vertical direction, and extends to the vicinity of the lower edge of the recording paper discharge port 157. A vertical wall 153. The mounting surface 152 is provided with a plurality of first ribs 154 that extend in the discharge direction and are arranged at intervals in the width direction orthogonal to the discharge direction.

  FIG. 2 is an enlarged perspective view showing the peripheral portion with the upper cover 171 removed. The apparatus main body 11 houses a cooling unit 51 that blows cooling air onto the recording paper discharged from the recording paper discharge port 157. The cooling unit 51 is blocked by the upper cover 171 (FIG. 1).

  The cooling unit 51 includes a cooling fan 52, a plurality of cooling air discharge ports 53 that discharge the cooling air from the cooling fan 52, and a duct 54 that guides the cooling air from the cooling fan 52 to the cooling air discharge port 53. . The cooling air discharge port 53 is a part of the duct 54.

  The duct 54 includes a branch path 55 branched into a plurality, and a connecting portion 56 that connects the cooling fan 52 and the branch path 55. The duct 54 has a cooling air discharge port 53 formed at each branch destination, and guides the cooling air generated by the cooling fan 52 to the cooling air discharge port 53. The cooling air discharge port 53 is disposed downward above the recording paper discharge port 157 so as to be aligned with the recording paper discharge port 157 in the vertical direction.

  FIG. 3 is a cross-sectional side view of the image forming apparatus 1. The image forming apparatus 1 includes an operation unit 47, a display unit 473, an image forming unit 12, a fixing unit 13, a paper feeding unit 14, and a cooling unit 51 in the apparatus main body 11.

  A case where an image forming operation is performed in the image forming apparatus 1 will be described. Based on image data received from a network-connected computer, the image forming unit 12 forms a toner image on the recording paper P fed from the paper feeding unit 14.

  The image forming unit 12 includes an image forming unit 12Bk for black (Bk), an image forming unit 12Y for yellow (Y), an image forming unit 12C for cyan (C), and an image forming unit 12M for magenta (M). The image forming units 12Bk, 12Y, 12C, and 12M each include a drum-type photosensitive member 121, and the photosensitive member 121 is driven to rotate counterclockwise in the drawing.

  The transfer unit 120 includes an intermediate transfer belt 125, a driving roller 125a, a driven roller 125b, and a primary transfer roller 126 on which a toner image is transferred to the outer peripheral surface thereof.

  The intermediate transfer belt 125 is stretched between the driving roller 125 a and the driven roller 125 b, is driven by the driving roller 125 a in contact with the peripheral surface of the photosensitive member 121, and runs endlessly in synchronization with the photosensitive member 121. To do.

  A case where color printing is performed will be described. The periphery of the photoconductor is uniformly charged (charging process), and a latent image is formed on the surface of the charged photoconductor 121 based on image data by irradiation with a laser beam (exposure process). Is visualized with toner (development process), and the toner image formed by the visualization is transferred onto the intermediate transfer belt 125 by the primary transfer roller 126.

  The toner images of the respective colors (black, yellow, cyan, and magenta) transferred onto the intermediate transfer belt 125 are superimposed on the intermediate transfer belt 125 with the transfer timing adjusted to form a color toner image.

  The secondary transfer roller 210 passes a color toner image formed on the surface of the intermediate transfer belt 125 from the paper supply unit 14 through the conveyance path 190 at a nip N1 between the intermediate transfer belt 125 and the drive roller 125a. It is transferred to the recording paper P that has been conveyed. The above description is for color printing. In the case of monochrome printing, the yellow, cyan, and magenta photoconductors 121 are not used, and only the black photoconductor 121 is used. Will be.

  The fixing unit 13 fixes the toner image on the recording paper by thermocompression bonding, and includes a heating roller that melts the toner on the recording paper P and a pressure roller that causes the recording paper P to adhere to the heating roller.

  The recording paper P on which the color image has been subjected to the fixing process is sent to the downstream side in the transport direction by the upper transport roller pair 191 and is discharged from the recording paper discharge port 157 to the discharge tray 151. The recording paper P discharged from the recording paper discharge port 157 is blown with cooling air discharged from the cooling air discharge port 53.

  The paper feeding unit 14 includes a paper feeding cassette and includes a pickup roller for picking up the recording paper P accommodated in the paper feeding cassette. The recording paper P picked up by the pick-up roller is fed to the lower conveyance roller pair. By 192, it is conveyed to the nip portion N1.

  FIG. 4 is a cross-sectional side view showing the recording paper discharge port 157 and its peripheral portion.

  The recording paper discharge port 157 is provided with a discharge roller pair 181 for discharging the recording paper P, and the discharge roller pair 181 includes a driving roller 182 and a driven roller 183. The driving roller 182 is driven to rotate, for example, counterclockwise in the drawing around the roller shaft 182a. The driven roller 183 rotates, for example, clockwise in the drawing according to the driving roller 182.

  The recording paper P subjected to the fixing process by the fixing unit 13 is sent to the downstream side in the transport direction by the upper transport roller pair 191 and is formed between the driving roller 182 and the driven roller 183 constituting the discharge roller pair 181. The sheet passes through the section N2, and is discharged from the recording paper discharge port 157 to the discharge tray 151.

  The cooling air discharge port 53 is disposed at a position on the downstream side in the conveyance direction of the recording paper discharge port 157 so that the cooling air is discharged downward. Further, the cooling air discharge port 53 is disposed downstream of the discharge roller pair 181 in the discharge direction. Alternatively, the cooling air discharge port 53 is disposed on the downstream side in the discharge direction with respect to the nip portion N <b> 2 formed by the discharge roller pair 181. FIG. 5 is an enlarged cross-sectional side view showing the discharge roller pair 181 and its peripheral portion. In FIG. 5, a broken line B1 indicates the position of the driving roller 182 and a broken line B2 indicates the position of the driven roller 183.

  The recording paper P discharged from the recording paper discharge port 157 is subjected to curl correction or the like by the recording paper pressing member 158. Further, the recording paper pressing member 158 is rotatable in the direction of the arrow shown in FIG. 4 by the support member 159 disposed on the upper frame constituting the discharge portion provided with the recording paper discharge port 157. It is supported by.

  The plurality of first ribs 154 extend on the loading surface 152 of the discharge tray 151 in the discharge direction of the recording paper P, and are spaced from each other in the width direction of the recording paper P perpendicular to the conveyance direction and the horizontal direction. It is installed side by side. The plurality of first ribs 154 form a gap between the recording paper P placed on the first rib 154 and the placement surface 152. The height of the first rib 154 from the mounting surface 152 is set to such a height (for example, 10 mm) that the cooling air discharged from the cooling air discharge port 53 can flow into the gap.

  In the first embodiment, since the cooling air discharge port 53 is disposed downward above the recording paper discharge port 157, the cooling air can be directly blown onto the recording paper P subjected to the fixing process. Thereby, the recording paper P stocked on the loading surface 152 of the discharge tray 151 can be cooled.

  Further, a gap through which the cooling air passes is formed between the recording paper P placed on the plurality of first ribs 154 and the placement surface 152, and the air is discharged from the cooling air discharge port 53 into the gap. Since the cooling air can flow in, the recording paper P stocked on the discharge tray 151 can be cooled not only from above but also from below the recording paper P. For this reason, according to the first embodiment, the cooling efficiency for the recording paper P discharged after fixing can be improved as compared with the conventional case. Here, the configuration in which the first rib 154 is provided on the placement surface 152 as a convex portion (the first convex portion in the claims) is described, but in another embodiment, Instead of the one rib 154, recesses that extend in the conveyance direction of the recording paper P and are arranged in parallel with a gap in the width direction of the recording paper P perpendicular to the conveyance direction and the horizontal direction (first in the claims) (Recessed portion) may be formed, and the cooling air discharged from the cooling air discharge port 53 may flow into the recessed portion.

  Next, an image forming apparatus 1 according to the second embodiment of the present invention will be described. FIG. 6 is a cross-sectional side view showing the recording paper discharge port 157 and its peripheral portion in the image forming apparatus 1 according to the second embodiment.

  In the image forming apparatus 1 according to the second embodiment, the recording paper P extends from one end of the loading surface 152 on the upstream side in the conveyance direction to the lower edge of the recording paper discharge port 157 upward in the vertical direction. A vertical wall 153 is provided. The vertical wall 153 is provided with a plurality of second ribs 185 that extend in the vertical direction from a height position that is the mounting surface 152 of the discharge tray 151 or the vicinity thereof. The plurality of second ribs 185 are provided on the vertical wall 153 at intervals in the width direction of the recording paper P. When the recording paper P is placed on the placement surface 152 by the plurality of second ribs 185, the upstream end of the recording paper P in contact with the second rib 185 in the transport direction and the vertical wall 153. A gap through which cooling air passes is formed. That is, the second rib 185 is such that the cooling air discharged from the cooling air discharge port 53 flows into the space formed by the recording paper P that contacts the second rib 185 and the vertical wall 153 (for example, 10 mm). Projects in the discharge direction. As a result, the recording paper P stocked on the discharge tray 151 abuts on the vertical wall 153, and the cooling air rotates around the gap between the recording paper P placed on the first rib 154 and the placement surface 152. Prevents you from getting stuck.

  In the second embodiment, although not an indispensable condition, the placement surface 152 on which the plurality of first ribs 154 are arranged side by side has an inclination that becomes lower on the upstream side in the conveyance direction of the recording paper P. It is preferable.

  FIG. 7 is a perspective view showing a state in which the recording paper P is placed on the placement surface 152 in the image forming apparatus 1 according to the second embodiment. FIG. 8 is a diagram illustrating a direction in which cooling air flows around the recording paper P placed on the placement surface 152 in the image forming apparatus 1 according to the second embodiment.

  As shown in FIG. 8, the cooling air discharged from the cooling air discharge port 53 first flows in the direction of the arrow A <b> 1 around the recording paper P placed on the placement surface 152. Then, the cooling air passes through the gap between the vertical wall 153 formed by the second rib 185 and the upstream end of the recording paper P in the transport direction, as indicated by the arrow A2, and below the recording paper P. Head to the side. The cooling air that has moved to the lower side of the recording paper P enters the gap between the recording paper P and the placement surface 152 that is formed by the first ribs 154. In addition, although the case where a convex part (the second convex part in the claims) is formed on the vertical wall 153 by providing the second rib 185 on the vertical wall 153 is described here, in another embodiment, Instead of the second rib 185 as the convex portion, a concave portion (second concave portion in the claims) that is arranged in parallel with a gap in the width direction of the recording paper P is formed in the vertical wall 153. It may be.

  The present invention is not limited to the configuration of the above embodiment, and various modifications can be made. For example, as another embodiment, the image forming apparatus 1 includes a first rib arranged at the center in the width direction of the recording paper P among the plurality of first ribs 154 provided on the placement surface 152 of the discharge tray 151. The height of the first rib 154 disposed at the end in the width direction may be higher than that of the 154.

  The present invention is not limited to the configuration of the above embodiment, and various modifications can be made. In the above embodiment, a printer is used as an embodiment of the image forming apparatus according to the present invention. However, this is only an example, and other electronic devices such as a copy function, a printer function, and a scanner are used. Other image forming apparatuses having a function and a facsimile function may be used.

  Moreover, in the said embodiment, the structure and process which were shown by the said embodiment using FIG. 1 thru | or FIG. 8 are only one Embodiment of this invention, and are not the meaning which limits this invention to the said structure and process.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 13 Fixing part 51 Cooling part 52 Cooling fan 53 Cooling air discharge port 151 Discharge tray 152 Loading surface 153 Vertical wall 154 First rib 157 Recording paper discharge port 181 Discharge roller pair 185 Second rib P Recording paper

Claims (5)

A fixing unit for fixing the toner image on the recording paper;
A recording paper discharge port for discharging the recording paper on the downstream side in the conveyance direction of the recording paper with respect to the fixing unit;
A pair of discharge rollers provided at the recording paper discharge port;
A discharge tray on which the recording paper discharged from the recording paper discharge port by the discharge roller pair is placed on a placement surface;
A cooling unit having a cooling fan and a cooling air discharge port for discharging cooling air from the cooling fan;
The cooling air discharge port is disposed downstream of the recording paper discharge port in the transport direction and above the recording paper discharge port, with the cooling air discharge direction facing downward,
A plurality of first convex portions or first concave portions extending in the transport direction of the recording paper are formed on the placement surface of the discharge tray,
The recording paper placed between the recording paper placed on the first convex portion and the placement surface or the placement surface by the plurality of first convex portions or first concave portions. An image forming apparatus in which a gap through which the cooling air passes is formed between the first recess and the first recess. The placement surface of the discharge tray is provided with a plurality of first ribs that extend in the transport direction of the recording paper and are arranged in parallel with a space in the width direction of the recording paper perpendicular to the transport direction. The first convex portion is formed,
2. The image formation according to claim 1, wherein a gap through which the cooling air passes is formed between the recording sheet placed on the first rib and the placement surface by the plurality of first ribs. apparatus.   The plurality of first ribs are higher in height of the first ribs disposed at the end portions in the width direction than in the first ribs disposed in the center portion in the width direction. The image forming apparatus according to claim 2, wherein the image forming apparatus is formed as described above. Further comprising a vertical wall extending from one end portion of the mounting surface on the upstream side in the transport direction to the lower edge portion of the recording paper discharge port upward in the vertical direction;
The vertical wall is formed with a second convex portion or a second concave portion extending in the vertical direction from the placement surface,
The mounting surface, wherein the first convex portion or the first concave portion is arranged side by side, has an inclination that the upstream side in the transport direction becomes lower,
Due to the second convex portion or the second concave portion, the end portion of the recording paper that contacts the second convex portion and the vertical wall, or the end portion of the recording paper that contacts the vertical wall and the second convex portion. The image forming apparatus according to claim 1, wherein a gap through which the cooling air passes is formed between the two recesses. A plurality of second ribs are provided on the vertical wall so as to protrude toward the downstream side in the transport direction, extend in the vertical direction from the placement surface, and are arranged at intervals in the width direction. Part is formed,
The image forming apparatus according to claim 4, wherein the plurality of second ribs form a gap through which the cooling air passes between an end portion of the recording paper contacting the second rib and the vertical wall.