JP2006171058A - Heat exhausting structure and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat exhausting structure provided with constitution capable of satisfactorily exhausting hot air accumulated in an apparatus while preventing the upsizing of the apparatus. <P>SOLUTION: In the heat exhausting structure provided with the constitution for exhausting the heat generated from a heat generating part by generating an air current near the heat generating part, an air current generation means is provided in one flowing direction of the air current so that the proximity of the heat generating part is at a negative pressure, and that the amount of the fresh air entering the air current passage at the negative pressure at the upstream side of the air current is set to be larger than that at the downstream side. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a heat exhaust structure and an image forming apparatus, and more particularly to a heat exhaust mechanism in a fixing device.

  As is well known, one of image forming methods is an electrophotographic method. In this system, when an electrostatic latent image formed on a photoconductor corresponding to a latent image carrier is subjected to visible image processing by receiving toner from a developing device, the toner image is recorded on a recording medium such as recording paper. The transferred toner image is fixed by a melting / penetrating action using heat and pressure in a fixing device.

  Conventionally, heat generated from a fixing device in order to prevent heat generated in the fixing device from causing an increase in temperature in the image forming device and thereby adversely affecting an image forming processing device disposed around the fixing device. A configuration for discharging the gas to the outside is adopted. As this configuration, it is a general configuration to arrange a heat fan near the fixing device (for example, Patent Document 1).

  Moreover, although it is not for exhaust heat, there is also a configuration in which ozone generated from the charging device is discharged using a fan (for example, Patent Document 2).

JP-A-11-231760 (paragraph "0009" column) Utility Model Registration No. 2554613 (page 2, left column, lines 22-32)

  When performing forced exhaust heat using a fan, airflow in the apparatus becomes a problem as disclosed in the patent literature. That is, there are cases where an air flow for efficient exhaust heat is not generated simply by installing a suction fan on the apparatus wall. For this reason, there is a problem that heat is trapped in the apparatus or ozone cannot be discharged well.

  In the patent document, in order to eliminate the above-described problems, a configuration is disclosed in which the number of fans is increased, a duct having a special structure is provided to configure an exhaust passage, or a plurality of ozone absorption filters are provided. ing.

  However, in the case of such a configuration, an installation space for components in the apparatus is required, which may increase the size of the apparatus due to an increase in the installation space in the apparatus.

  An object of the present invention is to provide an exhaust heat structure and an image forming apparatus having a configuration capable of satisfactorily exhausting hot air accumulated in the apparatus while preventing an increase in the size of the apparatus in view of the problems in the conventional exhaust heat structure. It is in.

  The invention according to claim 1 is an exhaust heat structure having a configuration in which an air flow is generated in the vicinity of the heat generating portion and heat generated from the heat generating portion is discharged, and an air flow generating means is provided in one of the flow directions of the air flow to provide the heat generation. It is characterized in that a relationship is set in which the vicinity of the part is made negative pressure and the amount of outside air entering the air flow passage made negative is larger on the upstream side than on the downstream side of the air flow.

  According to a second aspect of the present invention, in the exhaust heat structure according to the first aspect, the air flow passage is configured by a closed space portion extended along a longitudinal direction of the heat generating portion, and is formed on a wall portion of the closed space portion. Is provided with an outside air entry part, and the outside air entry part is characterized in that the entry area on the upstream side is larger than the downstream side of the air flow.

  According to a third aspect of the present invention, in the exhaust heat structure according to the first or second aspect, the outside air entry portion is configured by an opening, and the opening has a larger opening area on the upstream side than the downstream side of the airflow. It is characterized by that.

  According to a fourth aspect of the present invention, in the exhaust heat structure according to the third aspect, a plurality of the openings are provided along the flow direction of the air flow, and the upstream side in the flow direction is formed more than the downstream side. It is characterized by being.

  According to a fifth aspect of the present invention, in the exhaust heat structure according to the third aspect, a plurality of the openings are provided along the flow direction of the air flow, and the opening width on the upstream side in the flow direction is larger than that on the downstream side. It is characterized by being.

  According to a sixth aspect of the present invention, in the exhaust heat structure according to any one of the first to fifth aspects, a filter is disposed in the outside air entry portion, and the filter has a density on the upstream side in the flow direction of the airflow. Is characterized in that the relationship is rough and the density becomes finer on the downstream side.

  A seventh aspect of the invention is characterized in that the exhaust heat structure according to one of the first to sixth aspects is used in an image forming apparatus.

  According to an eighth aspect of the present invention, in the image forming apparatus according to the seventh aspect, a fixing device is used as the heat generating portion, and a roller capable of being heated and fixed while nipping and conveying the recording sheet is used for the fixing device. An air flow is generated along the longitudinal direction of the roller.

  According to the first and second aspects of the present invention, since the amount of air flowing into the air flow passage that is under negative pressure is greater on the upstream side than on the downstream side of the air flow, suction from the exhaust stage A large amount of outside air can be taken in a position where the force is weak. Thereby, the hot air in the vicinity of the heat generating portion can be efficiently recovered without requiring a special duct or a multistage structure. Moreover, since the outside air that has entered from the upstream side is less likely to be blocked by the outside air that has entered from the downstream side due to the small amount of outside air that has entered the downstream side, rectification in the airflow passage is promoted and exhaust efficiency is improved. It is possible to prevent the decrease in the exhaust heat efficiency from being reduced.

  According to the third aspect of the present invention, the opening area of the outside air entry portion is larger on the upstream side than the downstream side in the flow direction of the air flow, so that the amount of the incoming outside air on the upstream side rather than the downstream side is increased. Therefore, rectification can be performed without obstructing the flow caused by the outside air on the downstream side.

  According to the fourth and fifth aspects of the present invention, it is possible to increase the exhaust heat efficiency by improving the exhaust efficiency by promoting the rectification in the air flow passage with a simple configuration that only changes the number of openings or the opening width. .

  According to the invention described in claim 6, by simply changing the density of the filter provided in the opening, the entrance efficiency on the upstream side is increased rather than the downstream side, thereby facilitating rectification in the air flow passage and improving the exhaust efficiency. It becomes possible to improve.

  According to the seventh and eighth aspects of the present invention, exhaust heat can be promoted by increasing exhaust efficiency in the vicinity of a fixing device used as a heat generating portion, so that adverse effects on peripheral devices due to heat can be prevented in advance. Is possible.

  Hereinafter, the best mode for carrying out the invention will be described with reference to embodiments shown in the drawings.

  FIG. 1 is a view showing a main part of an image forming apparatus to which the exhaust heat structure according to the present embodiment is applied. In FIG. 1, the image forming apparatus is a copying machine, a printer, a facsimile machine using these electrophotographic methods, or these. Multi-function printers that combine the above, and printing presses are targets.

  In FIG. 1, an image forming apparatus 1 is not shown, but a photosensitive member as a latent image carrier for performing an image forming process therein, a charging process, a writing process, a developing process, a transfer process, and a photosensitive member. Each apparatus is equipped with a cleaning process. When an image is transferred to a recording sheet fed from a sheet feeding apparatus having a plurality of sheet feeding trays 2, the image is transferred to the recording sheet by a fixing device 3. The unfixed image is fixed, and the recording paper is discharged to the in-body paper discharge unit 1A.

  The fixing device 3 uses a heat roller fixing method in which the heating roller 3A and the pressure roller 3B are brought into contact with each other so that the toner melts and permeates using heat and pressure when the recording paper is nipped and conveyed. It has been.

On the wall surface of the exterior cover 1 </ b> B provided in the housing of the image forming apparatus 1, an outside air intake port 1 </ b> C configured with a plurality of openings is provided on the wall surface located in the vicinity of the fixing device 3.
The outside air intake port 1C provided in the exterior cover 1B has a plurality of the same along the longitudinal direction of the fixing device 3 corresponding to the axial direction of the rollers 3A and 3B provided in the fixing device 3 and a direction perpendicular thereto. It is configured by a rectangular hole of a size, and the outside air can be taken in as indicated by an arrow in the order that the inside of the housing is negatively pressured by the exhaust fan 5 corresponding to a means for generating an air flow in the vicinity of the fixing device 3. It has become.

FIG. 2 is a diagram showing a configuration of a heat exhaust unit for exhausting hot air in the vicinity of the fixing device 3 to the outside. In FIG. 2, an airflow path 6 composed of a stay is disposed above the fixing device 3. Yes.
The airflow passage 6 is open at the bottom facing the fixing device 3 and is extended along the longitudinal direction of the fixing device 3, and one side in the extending direction communicates with the exhaust duct 4.

An outside air entry portion 6A is provided on one side surface of the airflow passage 6, that is, the side surface facing the outside air intake port 1C provided in the exterior cover 1B.
The outside air entry portion 6A can increase the amount of ingress of outside air on the upstream side in the flow direction of the air flow corresponding to the front side of the apparatus, compared to the downstream side in the flow direction of the air flow corresponding to the back side opposite to the front side of the apparatus. It is configured. The flow direction in this case is a direction in which the air flows from the outside air intake port 1C (see FIG. 1) and flows toward the exhaust duct 4 in accordance with the discharge direction of the air flow by the exhaust fan 5 (the direction indicated by the symbol F in FIG. Say.

  The outside air entry portion 6A shown in FIG. 2 is configured by a single hole whose opening area is larger on the upstream side in the airflow direction than on the downstream side. In other words, the opening area is narrowed from the upstream side toward the downstream side so as to become narrower.

  Since the present embodiment has the above-described configuration, the amount of outside air entering the outside air entry portion 6A is larger on the upstream side in the flow direction than on the downstream side. In other words, since the amount of entry on the downstream side is reduced, the outside air that has entered from the upstream side is less likely to be blocked by the outside air that enters from the downstream side, and as a result, the inside of the airflow passage is rectified. Will be.

  In particular, the amount of outside air taken into the airflow passage 6 can be increased by increasing the amount of inflow on the upstream side in the flow direction, which is far from the exhaust fan 5 in the airflow passage 6 by reducing the amount of outside air in the vicinity of the exhaust fan 5. This prevents the amount from becoming insufficient, thereby making it easier to take in the hot air from the periphery of the fixing device 3 corresponding to the position where the suction force by the exhaust fan 5 is weak within the airflow passage 6 that has been made negative. it can.

  FIG. 3 shows a modification of the outside air entry portion 6A provided in the stay constituting the airflow passage 6. In FIG. 3A, the flow direction of the outside air flows from the upstream side to the downstream side along the longitudinal direction of the airflow passage 6. The outside air entry portion is configured by a plurality of openings 6A1 that gradually decrease in width toward the side (indicated by reference symbol L in FIG. 3A). In FIGS. 3B and 3C, the opening width ( L) is the same, and in the longitudinal direction of the air flow passage 6, the rectangular air flow 6A2 (see FIG. 3B) has a larger number of upstream sides in the flow direction of the outside air than the downstream side. )) Or a round hole or a long hole 6A2 ′ (see FIG. 3C) constitutes the outside air entry portion.

  In the configuration shown in FIG. 3 as well, the amount of outside air entering on the upstream side in the flow direction of the airflow is greater than that on the downstream side, and the amount of outside air taken in at a position where the pressure from the exhaust fan 5 is weak is increased. It is possible to easily collect the hot air in the vicinity.

On the other hand, as the outside air entry section, the form of the outside air intake port provided in the exterior cover 1B of the housing inside the apparatus housing is used, or the form of the outside air entry section 6A on the airflow passage 6 side located inside the apparatus. It is also possible to correspond to.
4 and 5 show an example in which an outside air intake portion is configured on the exterior cover 1B. In FIG. 4, the outside air entry portion (indicated by reference numeral 1C1 for convenience) has the same size as the outside air intake port 1C shown in FIG. Is formed by a rectangular hole formed by sequentially reducing the numerical aperture from the upstream side (corresponding to the front side of the apparatus) to the downstream side (corresponding to the back side of the apparatus). Unlike the configuration shown in FIG. 4, the entrance portion (indicated by reference numeral 1C2 for the sake of convenience) has a small-sized rectangular hole or elongated hole that is sequentially reduced in numerical aperture from the upstream side to the downstream side in the air flow direction. Has been.

  On the other hand, as a configuration for reducing the amount of outside air entering as it goes from the upstream side to the downstream side in the flow direction of the airflow, it is possible to restrict not only the opening form described above but also the state of the outside air entering. That is, although not shown, a dustproof filter for preventing dust from entering from the outside may be provided in an opening such as an intake port formed in the exterior cover. For this reason, the roughness of the dustproof filter is made finer from the upstream side to the downstream side in the airflow direction. In other words, the density of the filter is increased on the upstream side in the flow direction of the airflow, and the density is reduced as it goes downstream. Thereby, the approach amount of the outside air on the downstream side in the flow direction upstream of the airflow can be reduced, and the same effect as the above-described opening form can be obtained.

It is a figure which shows the principal part of the image forming apparatus to which the waste heat structure by the Example of this invention is applied. It is a figure which shows the principal part structure of the exhaust heat structure by this invention Example. It is a figure which shows the modification regarding the principal part structure of the exhaust heat structure shown in FIG. It is a figure which shows another example regarding the exhaust heat structure shown in FIG. It is a figure which shows the other example regarding the waste heat structure shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 3 Fixing apparatus 3A Heating roller 3B Pressure roller 4 Exhaust duct 5 Exhaust fan 6 Airflow path 1C1, 6A Outside air entrance part 6A1 Opening

Claims (8)

In the exhaust heat structure having a configuration in which an air flow is generated in the vicinity of the heat generating part and heat generated from the heat generating part is discharged,
An air flow generating means is provided in one of the flow directions of the air flow to make negative pressure in the vicinity of the heat generating portion, and the amount of outside air entering the negative pressure air flow passage is larger on the upstream side than on the downstream side of the air flow. An exhaust heat structure characterized in that a relationship is established. The exhaust heat structure according to claim 1,
The air flow passage is configured by a closed space portion that extends along the longitudinal direction of the heat generating portion, and an outside air entry portion is provided in a wall portion of the closed space portion, and the outside air entry portion is disposed downstream of the air flow. An exhaust heat structure characterized in that the entrance area on the upstream side is larger than the side. The exhaust heat structure according to claim 1 or 2,
The exhaust heat structure according to claim 1, wherein the outside air entry portion is configured by an opening, and the opening has an opening area on the upstream side larger than the downstream side of the air flow. The exhaust heat structure according to claim 3,
A plurality of the openings are provided along the flow direction of the air flow, and the upstream side in the flow direction is formed more than the downstream side. The exhaust heat structure according to claim 3,
A plurality of the openings are provided along the flow direction of the airflow, and the opening width on the upstream side in the flow direction is made larger than that on the downstream side. The exhaust heat structure according to any one of claims 1 to 5,
A filter is disposed in the outside air entry portion, and the filter has a relationship in which the density is coarse on the upstream side in the flow direction of the air flow and the density is fine on the downstream side.   An image forming apparatus using the exhaust heat structure according to claim 1. The image forming apparatus according to claim 7.
A fixing device is used as the heat generating portion, and a roller capable of being heated and fixed while sandwiching and conveying a recording sheet is used for the fixing device, and an air flow is generated along the longitudinal direction of the roller. Image forming apparatus.

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