JP2006072200A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus, wherein space saving, user's visibility, and operability are compatible with each other. <P>SOLUTION: A duct 61 which takes in outdoor air and blows the air to a recording material is formed and a fan 60 is arranged in the duct 61. When the duct 61 has an inhalation side and an ejection side partitioned by the fan 6, at least a portion of a control substrate 55a is arranged on the inhalation side. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus such as a copying machine or a printer provided with a fan or the like for cooling a sheet after fixing.

  FIG. 4 is a cross-sectional view showing the configuration of the image forming unit of the image forming apparatus, which will be described in the image formation of a color image.

  For example, photosensitive drums a (yellow), b (magenta), c (cyan), and d (four image forming media arranged in parallel to form toner images of colors of yellow, magenta, cyan, and black, respectively. Black) and an intermediate transfer belt 2 which is a transfer conveying means arranged in a manner of cutting the photosensitive drums a to d vertically.

  A primary charger, a developing device, and a transfer charger (not shown) are arranged around the photosensitive drums a, b, c, and d driven by a motor (not shown), and these units are united as process cartridges 1a to 1d. It has become.

  An exposure device 6 composed of a polygon mirror or the like is disposed below the photosensitive drums a to d.

  First, laser light based on a yellow component color image signal of an original is projected onto the photosensitive drum a through a polygon mirror of the exposure device 6 to form an electrostatic latent image on the photosensitive drum a. Then, the yellow toner is supplied and developed, and the electrostatic latent image is visualized as a yellow toner image.

  When the toner image arrives at the primary transfer portion where the photosensitive drum a and the intermediate transfer belt 2 come into contact with the rotation of the photosensitive drum a, the primary transfer bias applied to the transfer charging member 2a causes the toner image on the photosensitive drum a. The yellow toner image is transferred to the intermediate transfer belt 2 (primary transfer).

  When the portion of the intermediate transfer belt 2 carrying the yellow toner image moves to the image forming unit, a magenta toner image is formed on the photosensitive drum b by the same method as described above in the image forming unit, and this magenta toner image Is transferred onto the intermediate transfer belt 2 from the yellow toner image.

  Similarly, as the intermediate transfer belt 2 moves, the cyan toner image and the black toner image are transferred onto the yellow toner image and the magenta toner image at the respective primary transfer portions of the image forming unit.

  The recording material P is fed one by one from the cassette 4 containing the recording material P by the pickup roller 8, timed by the registration roller 9, and then reaches the secondary transfer portion and reaches the secondary transfer roller pair 3. The four-color toner images on the intermediate transfer belt 2 are collectively transferred onto the recording material P by the applied secondary transfer bias (secondary transfer).

The recording material P onto which the four color toner images have been transferred is guided by the conveyance guide 20 in the secondary transfer roller pair to the fixing roller pair and conveyed to the fixing roller pair 5 where it is fixed by receiving heat and pressure. As a result, each color toner is melted and mixed to form a full-color print image fixed on the recording material P, and then discharged onto the discharge tray 7 by the discharge-conveying roller pair 11 provided downstream of the fixing roller pair 5. The (For example, refer to Patent Document 1.)
FIG. 5 is a view of the image forming apparatus as viewed from above, and shows the field of view of the user when operating the image forming apparatus. The operation panel 50 is disposed on the upper surface of the image forming apparatus so that the user can visually recognize the operation panel and can easily perform the operation. However, the operation panel 50 is disposed outside the area occupied by the fixing roller pair 5 (for example, patents). Reference 2).
JP 2003-287938 JP 2001-063175 A

  The operation panel 50 is disposed in a portion outside the area occupied by the fixing roller pair 5 because the control board that operates the operation panel 50 is heated by the heat from the fixing roller pair 5 and the recording material P after fixing and malfunctions. This is to avoid doing.

  However, the image forming apparatus is still required to save space in order to effectively use the user's work space. When the operation panel 50 must be disposed while avoiding the fixing roller pair 5, While there are restrictions on the layout and size of the operation panel, it is necessary to reduce the size of the operation panel. On the other hand, the image forming device has a universal design to make it easier for many users to use, and the number of replacement parts in the color device has increased. In order to convey information to the user in an easy-to-read and easy-to-understand manner from the viewpoint of diversification of settings, there is a background that requires an increase in the size of the LCD screen and operation buttons, so there is a problem that operability and visibility cannot be sacrificed. It was.

  Further, since the space saving of the image forming apparatus involves a high-density arrangement inside the image forming apparatus, not only the control board of the operation panel 50 but also various control boards are arranged so as not to be affected by the heat of the fixing roller pair 5. There was a problem that is becoming difficult. In addition, when the speed of the image forming apparatus is improved, the recording material P is discharged out of the apparatus at a high temperature, and the recording materials P are stacked on the recording material P on the tray 7 before the toner is fixed. There has been a problem that the recording material P needs to be cooled together with the problem of being adhered.

  A typical configuration of the image forming apparatus according to the present invention for solving the above-described object includes a fixing unit that fixes a toner image on a recording material by heat and pressure, and a recording material on which the toner image is fixed by the fixing unit. A conveyance roller that is disposed between the fixing unit and the conveyance roller, guides the recording material, an outside air intake port, and an opening formed in the conveyance guide for the outside air taken in from the intake port A duct for spraying from the recording material to the recording material, and disposing at least a part of the control board and the air blowing means in the duct, and when the duct is on the suction side and the discharge side with the air blowing means as a boundary, At least a part of the control board is arranged on the suction side.

  As described above, according to the present invention, a duct that takes in outside air and blows air onto the recording material after fixing is formed, and a blowing means is disposed in the duct, and the duct is separated from the suction side and the discharge side with the blowing means as a boundary. In this case, by arranging at least a part of the control board on the suction side, the control board is cooled by the outside air sucked by the blowing means, and an efficient air flow is formed in which the recording material P is cooled by the exhaust of the blowing means. In addition, it is possible to provide an image forming apparatus that can dispose the control board around the fixing unit and achieves both space saving and user visibility and operability.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings.

  Since the image forming operation of the image forming apparatus is the same as that described in the background art, the description thereof is omitted.

  FIG. 1 is an explanatory view of a main part of a discharge airflow of the image forming apparatus according to the first embodiment of the present invention.

  An operation panel 55, a fan 60, a partition wall 61a, and an exterior 61b are disposed above the pair of fixing rollers 5 as fixing means for fixing the toner image to the recording material with heat and pressure.

  The operation panel 55 includes a control board 55a, a liquid crystal panel 55b, buttons 55c (shown in the boss diagram of FIG. 2), and the like, and displays and sets the state of the image forming apparatus. The control board 55a is connected to the liquid crystal panel 55b and the button 55c, and controls the operation contents to the liquid crystal panel 55b and the button 55c by the operator to be input as information and to perform a predetermined display on the liquid crystal panel 55b. .

  The fan 60 is installed in the partition wall 61a, and the duct 61 is formed by the partition wall 61a and the exterior 61b. When the fan 60 is activated, outside air is taken in through the slit 61c (outside air intake port) formed in the duct 61 (air flow 65a), and the taken-in outside air is sucked into the fan 60 while passing through the control board 55a and the liquid crystal panel 55b. (Airflow 65b).

  That is, the duct 61 forms an air flow on the suction side. Exhaust air from the fan 60 is blown to the recording material P through the slit 22a formed in the paper discharge guide 22 (air flow 65c), and the blown air is discharged from a paper discharge port provided with the paper discharge roller pair 11 as a transfer roller. The air is exhausted outside (air flow 65d). That is, the paper discharge port having the paper discharge guide 22 and the paper discharge conveyance roller pair 11 has a function of a duct, and forms an air flow on the discharge side.

  When the fixing roller pair 5 generates heat by the image forming operation, the heat of the fixing roller pair 5 and the recording material P is transmitted to the paper discharge guide 22 and is transmitted to the duct 61, and the temperature in the duct 61 rises. If the fan 60 is operating at this time, the outside air enters the duct 61 by the air flow 65a, and the air flow 65b exchanges the air in the duct 61. Therefore, the heat of the fixing roller pair 5 and the recording material P enters the duct 61. The temperature rise in the duct 61 can be suppressed to the minimum without being trapped. In the experiment, the temperature in the duct 61 was 50 to 60 ° C., and no problem occurred in the operation of the operation panel 55.

  The airflow 65b also has a function of suppressing the heat generation of the elements because it directly cools the control board 55a and the liquid crystal panel 55b, and can deal with elements that generate a large amount of heat, such as a color liquid crystal panel. The air flow 65c has a function of cooling the recording material P and discharging water vapor generated from the recording material P to the outside of the apparatus to prevent condensation of the paper discharge guide 22. The fan 60 is disposed so as to be inclined toward the discharge conveyance roller side with respect to the surface formed of the recording material P, and the air flow 65c is generated in a direction that makes an acute angle with respect to the recording material P to be discharged outside the apparatus. ing. A fan 60 is disposed in the vicinity of the paper discharge guide 22 in order to increase the wind speed when hitting the recording material P. Since the air flow 65d discharged outside the apparatus has an effect of continuously cooling the recording material P being discharged, the recording material P can be efficiently cooled. If the airflows 65c and 65d flow backward to the suction side of the fan 60, the ambient temperature of the control board 55 rises. Therefore, the suction side and the discharge side of the fan 60 are separated by a partition wall of the duct 61 to prevent backflow. Yes.

  Even after the image formation is completed, the paper discharge guide 22 is warmed by the residual heat of the fixing roller pair 5, and therefore the fan 60 is operated for a predetermined time after the image formation is completed. In order to shorten the image formation time, when preheating is applied to the fixing roller pair 5 during non-image formation, the rotation speed may be lowered and the operation may be always performed. In recent years, there has been proposed a fixing method that does not give preheating for energy saving, and it may not be necessary to operate depending on the heat resistant temperature of the control board 55, but in many cases, a predetermined method is used to avoid the influence of residual heat after image formation. The time fan 60 is operating.

  FIG. 2, which is a top view of the image forming apparatus, shows a user field of view when operating the image forming apparatus, and improves the visibility and operability of the operation panel 55 compared to FIG. 5, which is the prior art. It can be seen that As shown in FIG. 2, the operation panel 55 is provided within the width of the fixing roller pair 5 in the longitudinal direction. Two fans 60 are arranged to form an air flow in the entire sheet passing width and to form an air flow in the longitudinal direction of the operation panel. If a large fan is used, it is possible to form an air flow over the entire width of the sheet passing only by placing one at the center, but the efficiency is poor in terms of installation space and cost. Although the wind speed of the airflow is adjusted using a diversion rib (not shown), wind speed unevenness often occurs. However, in order to prevent adhesion of the recording material P, there is no problem if the temperature is lower than a predetermined temperature.

  In the present embodiment, the operation panel 55 is illustrated as being provided within the width of the fixing roller pair 5 in the longitudinal direction (axial direction). However, the operation panel 55 has a width in the longitudinal direction of the fixing roller pair a. If the portions overlap, it contributes to downsizing of the apparatus main body in the longitudinal direction.

  In the first embodiment, an example is shown in which an axial fan is adopted as the fan 60 in consideration of cost and installation space. However, the present invention is not limited to the axial fan and can be applied to a cross flow fan or the like. is there. In the case of an axial fan, as shown in FIG. 2, a plurality of airflows are formed to form an airflow over the entire sheet passing width. However, a single crossflow fan can be used, and the wind speed variation is small. However, since the structure of the cross flow fan is complicated, it is generally more expensive than several axial flow fans.

(Second embodiment)
Hereinafter, a second embodiment according to the present invention will be described in detail with reference to the drawings.

  FIG. 3 is an explanatory view of the main part of the sheet discharge airflow of the image forming apparatus according to the second embodiment of the present invention.

  The second embodiment of the present invention is greatly different from the image forming apparatus of the first embodiment in that it has an automatic duplex function. Hereinafter, differences from the first embodiment will be described in detail, and description of other configurations similar to those of the first embodiment will be omitted.

  The automatic double-side function includes a double-sided roller pair 12, a flapper 26, a double-sided guide 27, and a motor control board 56 that is a control board of the present invention. The motor control board 56 controls a motor (not shown) to control the rotation of the paper discharge conveyance roller pair 11 and the double-sided roller pair 12. On the first image forming side, the pair of paper discharge transport rollers 11 is driven in the direction to discharge the recording material P to the tray 7, and the flapper 26 is located at the position of the flapper 26 ′ by the trailing end of the recording material P being removed. Is detected by a sensor (not shown) and the pair of paper discharge rollers 11 is rotated in the reverse direction. By doing so, the recording material P is guided to the double-sided guide 27 and is conveyed to the registration roller 9 through a merging path (not shown) by the double-sided roller pair 12. By doing so, it is possible to form an image on the second surface of the recording material P, and automatic double-sided is realized.

  The motor control board 56 is disposed in the vicinity of the fixing roller pair 5 via the double-sided guide 27 and operates in an environment having a higher atmospheric temperature than the outside air. Nevertheless, components with little self-heating can operate without problems if the ambient temperature is 70 ° C. or lower. However, since the driver chip 56a for driving the motor has a large amount of self-heating, the driver chip 56a includes a heat sink 56b. A part of the heat sink 56b is arranged in the duct 61 so as to fill the gap with the sealant 62 in order to enhance the cooling effect. When the fan 60 is actuated, outside air is taken in and the heat is dissipated when the air flow 65a passes through the heat sink 56b, so that the driver chip 56a can be efficiently cooled.

  The reason why only a part of the motor control board 56 is placed in the duct 61 is to minimize the portion of the duct 61 that is freed, thereby enabling cooling of the necessary portion while minimizing the decrease in efficiency of the duct 61. It is to do. If the gap is not filled with the sealing material 62, the atmospheric temperature of the control board flows into the duct 61 in addition to the outside air, so that the cooling efficiency is lowered.

  When the ambient temperature of the motor control board 56 is further increased, it is possible to arrange the control board in the duct 61 and perform wiring using a relay connector or the like. Is concerned.

  Compared with the first embodiment of the present invention, the temperature of the air flow 65b of the heat generated by the driver chip 56a is affected, but the influence is sufficiently compared with the effects of the fixing roller pair 5 and the recording material P. Since it is small, there is no problem with the operation of the operation panel 55.

  According to the first and second embodiments, a duct for blowing air to the recording material P after fixing and forming air is formed, and a blowing means is arranged in the duct, and the duct is discharged from the suction side with the blowing means as a boundary. By arranging at least a part of the control board on the suction side, the control board is cooled by the outside air sucked by the blowing unit, and the recording material P is cooled by the exhaust air of the blowing unit. It is possible to provide an image forming apparatus which can be formed and the control board can be disposed around the fixing device, and both space saving and user visibility and operability can be achieved.

FIG. 3 is an explanatory view of a main part of the image forming apparatus according to the first embodiment. FIG. 3 is an explanatory diagram of a user viewpoint of the image forming apparatus according to the first embodiment. FIG. 5 is a main part explanatory view of an image forming apparatus according to a second embodiment. Explanatory drawing of the image forming apparatus which concerns on a prior art. FIG. 6 is a user viewpoint explanatory diagram of an image forming apparatus according to a conventional technique.

Explanation of symbols

5 Fixing roller pair 22 Paper discharge guide 55a Control board 60 Fan 61 Duct

Claims (11)

Fixing means for fixing the toner image to the recording material by heat and pressure;
A conveyance roller for conveying the recording material on which the toner image is fixed by the fixing unit;
A conveyance guide that is disposed between the fixing unit and the conveyance roller and guides a recording material;
The outside air intake,
A duct for blowing the outside air taken in from the take-in port to the recording material from an opening formed in the transport guide,
Arranging at least a part of the control board and the air blowing means in the duct,
An image forming apparatus according to claim 1, wherein at least a part of the control board is disposed on the suction side when the duct is provided on the suction side and the discharge side with the air blowing means as a boundary.   The image forming apparatus according to claim 1, wherein the air blowing unit is disposed above the fixing unit.   3. The image forming apparatus according to claim 1, wherein an angle formed between a direction of air blown by the blowing unit and the recording material plane is an acute angle with respect to a discharge direction of the recording material.   The image forming apparatus according to claim 1, wherein a part of the duct also serves as an exterior surface.   The image forming apparatus according to claim 1, wherein the control substrate is disposed above the fixing unit.   The image forming apparatus according to claim 1, wherein the control board constitutes an operation panel that allows a user to display and operate information.   The image forming apparatus according to claim 1, wherein the control board is a control board that performs motor control.   The image forming apparatus according to any one of claims 1 to 7, wherein the control board includes a heat sink, and the heat sink is provided so as to protrude from the outside of the duct into the duct.   The image forming apparatus according to any one of claims 1 to 8, wherein an air flow on the suction side of the duct is formed along a short direction of the control board.   The image forming apparatus according to any one of claims 1 to 9, wherein an air flow on the suction side of the duct is formed along a conveyance direction of the recording material.   11. The image forming apparatus according to claim 1, wherein a plurality of the blowing units are arranged in the conveyance guide width or in the longitudinal direction of the control substrate.

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