JP2003186326A - Image-forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image-forming apparatus which does not impair fixing properties and can reduce temperature rise of a member located in the vicinity of a fixing device not present the risk of being accessed by a hand of a user. <P>SOLUTION: In the image-forming apparatus, a recording medium having a formed image is fixed by a heating and fixing device, the heated and fixed recording medium is ejected to a recording medium ejecting part, provided in an upper part of an image-forming apparatus main, and ventilation holes are provided in a bottom part located, in the vicinity of an end on the heating and fixing device side of the recording medium ejecting part. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a printer, a copying machine or a facsimile which adopts an electrophotographic system, and more particularly to an image forming apparatus which adopts a mechanism for reducing a temperature rise near a fixing device. Is.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a printer, a copying machine, a facsimile, etc., which employs this type of electrophotographic system, the surface of a photosensitive drum is uniformly charged to a predetermined potential and then the photosensitive drum The surface of the body drum is imagewise exposed to form an electrostatic latent image, and the electrostatic latent image formed on the surface of the photosensitive drum is visualized by a developing device to form a toner image. After the transfer, the recording paper on which the toner image has been transferred is fixed by heat and pressure by a fixing device to form an image.

By the way, in such an image forming apparatus, particularly in a small printer, in order to reduce the installation space, the recording paper on which an image is formed is discharged onto a paper discharge tray provided on the upper part of the printer body. The one configured as described above is used in various ways.

As described above, by providing the paper discharge tray on the upper part of the printer body, in a small printer or the like having a small installation space, the recording paper on which the toner image is transferred is subjected to fixing processing by heat and pressure. The fixing device to apply is
Due to its configuration, it is inevitably arranged near the paper discharge tray. Therefore, the cover member of the printer body located in the vicinity of the fixing device may be heated to a high temperature by the heat from the fixing device and may be deformed, or the cover member that is accidentally heated to a high temperature may be touched by the hand. Had a point.

As a technique capable of solving such a problem, for example, there is one disclosed in Japanese Patent Laid-Open No. 2000-3083. As shown in FIGS. 9 and 10, the electrophotographic image forming apparatus according to Japanese Patent Laid-Open No. 2000-3083 includes a thermal fixing unit 101 that applies heat to a recorded sheet 100 to fix the image on the sheet. , The heat-fixing section 101 is housed, and the recorded sheet 1 after image fixing by the heat-fixing section 101
00, a sheet discharge stacking unit 104 on the image forming apparatus main body 103 that sequentially stacks the recorded sheets 100 discharged by the discharge unit 102, the sheet discharge stacking unit 104, and the heat fixing unit 101. Ventilation hole 10 provided between
And a standing wall having 5.

Among the above-mentioned image forming apparatuses, particularly in a small-sized printer, as shown in FIG. 11, in a double-sided unit 201 having a sheet reversing mechanism 200, as disclosed in Japanese Patent Laid-Open No. 11-296053. To fan 202
Is provided to cool the duplex unit 201 and the paper 203 that is being reversed, and to operate the fan 202 to assist in cooling the printer body 204.

[0007]

However, the above-mentioned prior art has the following problems. That is, in the case of the electrophotographic image forming apparatus according to Japanese Unexamined Patent Application Publication No. 2000-3083, as shown in FIGS. 9 and 10, since the ventilation hole 105 is provided in the standing wall portion 106, the sheet is discharged. Since the wind flows along the horizontal direction with respect to the topmost sheet 100 stacked on the tray 104, when the stacking amount of the sheets 100 increases, the air does not flow to the lower part of the standing wall portion 106, so that the sheet stands up. There is a problem that the cooling efficiency of the lower portion of the wall portion 106 is poor. In this regard, in the above-mentioned Japanese Patent Laid-Open No. 2000-3083, the standing wall portion 1
Although a configuration in which a rib is provided on the outer surface of 06 is disclosed, when the ventilation hole 105 is provided in the standing wall portion 106,
Inevitably, the wind flows along the horizontal direction with respect to the topmost sheet 100 stacked on the sheet ejection tray 104, so that even the lower portion of the standing wall portion 106 cannot be efficiently cooled. Had a point.

Further, in the case of the technique disclosed in Japanese Patent Laid-Open No. 10-104878, there is a possibility that the user may touch near the fixing device because the heat from the fixing device and the temperature immediately after fixing are high. If the fan 202 in the double-sided unit 201 is operated when the temperature becomes high due to the influence of the paper, as shown in FIG. Since the inside is also cooled at the same time, there is a problem that the cooling efficiency in the vicinity of the fixing device 205 is worse than that in the case where it is specialized.

In order to avoid the above problems,
It is conceivable to lower the set temperature of the fixing device, but in this case, the fixing property is lowered, and other problems such as a decrease in the number of prints per unit time are newly caused.

Therefore, the present invention was made in order to solve the above-mentioned problems of the prior art, and the purpose of the present invention is to allow a user to manually touch the fixing device in the vicinity thereof without sacrificing the fixing property. An object of the present invention is to provide an image forming apparatus capable of reducing a temperature rise of a member that may be touched.

[0011]

In order to solve the above-mentioned problems, the invention described in claim 1 fixes a recording medium on which an image is formed by a heat fixing device, and the heat-fixed recording medium. In the image forming apparatus for discharging the recording medium to the recording medium discharging section provided at the upper part of the image forming apparatus main body, a ventilation hole is provided in the bottom portion located near the end of the recording medium discharging section on the heating and fixing device side It was done.

As described above, according to the first aspect of the invention, since the ventilation hole is provided in the bottom portion of the recording medium discharging portion located near the end of the recording medium discharging portion on the side of the heat fixing device, the recording medium discharging portion is formed. Since the wind always flows downward from the uppermost recording medium stacked on the recording medium, it is possible to efficiently cool the lower portion of the member on the heating fixing device side of the recording medium discharging portion. Also,
In the invention described in claim 1, since a downward force is applied to the heat fixing device side (rear end side) of the recording medium by the flowing air, the wind is blown from the uppermost recording medium stacked in the recording medium discharge portion. Always flows downward, and the storability in the recording medium ejecting section is improved.

According to the second aspect of the present invention, a rib for preventing the recording medium from covering the ventilation hole is provided on the surface of the standing wall located at the end of the recording medium discharge section on the heating and fixing device side. The image forming apparatus according to claim 1, wherein the image forming apparatus is provided.

As described above, in the invention described in claim 2, by providing the rib for preventing the recording medium from covering the ventilation hole, the recording medium does not block the ventilation hole. The effect of the invention can be obtained more reliably.

Further, in the invention described in claim 3, the recording medium on which the image is formed is fixed by the heat fixing device, and the recording medium on which the heat is fixed is provided on the upper portion of the main body of the image forming apparatus. A double-sided sheet for discharging the medium to the medium discharge section and conveying the recording medium having the image formed on one side to the image forming section again when the image is formed on both sides of the recording medium on the side of the image forming apparatus main body. In an image forming apparatus provided with a unit, an auxiliary cooling fan is installed inside the double-sided unit in the vicinity of an opening for conveying a recording medium from the image forming apparatus main body to the double-sided unit. is there.

As described above, according to the third aspect of the invention, the auxiliary cooling fan opens the opening in the image forming apparatus main body from the vicinity of the opening for conveying the recording medium from the image forming apparatus main body to the duplex unit. The heat from the heat fixing device arranged near the fixing unit can be discharged, the auxiliary cooling fan can be specialized for cooling the vicinity of the heat fixing device, and the cooling efficiency near the fixing device can be improved. it can. In particular, it is particularly effective when the recording medium heated by the heat fixing device is conveyed from the opening of the image forming apparatus main body into the duplex unit, and the temperature in the vicinity of the heat fixing device tends to rise.

In the invention described in claim 3, the effect can be further enhanced by providing an inflow prevention member for preventing air from flowing into the auxiliary cooling fan from the inside of the double-sided unit.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1 FIG. 2 shows a printer as an image forming apparatus according to Embodiment 1 of the present invention.

In FIG. 2, reference numeral 1 denotes a main body of a printer as an image forming apparatus. The inside of the printer main body 1 is an image forming unit 2 which can be easily replaced by a user when toner runs out. Is provided. This image forming unit 2 is, as shown in FIG.
Broadly speaking, the photosensitive drum 3 as an image carrier, the charging roll 4 for charging the surface of the photosensitive drum 3, and the electrostatic latent image formed on the surface of the photosensitive drum 3 are developed as described later. The developing device 5 and a cleaning device 6 for removing toner and the like remaining on the surface of the photosensitive drum 3 are included.

As the photosensitive drum 3, for example, O
A photoconductor including a PC is used, and the photoconductor drum 3 is used.
Are driven to rotate at a predetermined rotation speed in the direction of the arrow. The surface of the photosensitive drum 3 is uniformly charged to a predetermined potential by the charging roll 4, and then ROS (Raster Output Scanner) as an image exposure device.
Image exposure is performed by 7, and an electrostatic latent image corresponding to image information is formed. The electrostatic latent image formed on the surface of the photosensitive drum 3 is developed by the developing device 5 to become a toner image, and this toner image is recorded on a recording paper 8 as a recording medium.
It is electrostatically transferred onto the surface by the transfer roll 8a. The recording paper 8 is supplied from a paper feed cassette 9 arranged at the bottom of the printer body 1 or an optional paper feed cassette (not shown) which is added to the lower portion of the printer body 1 as required. Paper of a size is fed by the paper feed roll 10 and is conveyed by the registration roll 10 to the transfer position of the photosensitive drum 3 at a predetermined timing. The recording paper 8 on which the toner image is transferred is conveyed to a fixing device 11, and the fixing device 11 fixes the toner image on the recording paper 8 by heat and pressure. 1 is ejected onto a paper ejection tray 13 serving as a recording medium ejection unit provided on the upper part of
The normal single-sided printing operation ends.

On one side surface (right side surface in the illustrated example) of the printer body 1, a main cooling fan for discharging the heated air in the printer body 1 to the outside to cool the inside of the printer body 1. 14 is provided.

Further, in the above printer, when images are printed on both sides of the recording sheet 8, the recording sheet 8 having the image formed on one side is not directly discharged onto the discharge tray 13 but the recording sheet 8 is not discharged. With the trailing end nipped by the discharge roll 12, the discharge roll 12 is rotated in the reverse direction, and the paper conveyance path 1 is moved by the straightness due to the rigidity of the recording paper 8 itself or the gate member for switching the conveyance path.
5 is switched and the sheet is conveyed into the duplex unit 16.

This double-sided unit 16 is, as shown in FIG. 2, one side surface of the printer body 1 (right side surface in the illustrated example).
Is attached to. The duplex unit 16 is optional, and one side surface (right side surface in the illustrated example) of the printer body 1 is directly covered by a cover (not shown) when the duplex unit 16 is not mounted. The duplexer 16 includes the printer body 1
Opening 17 for introducing a sheet near the fixing device 11
And a curved double-sided sheet transport path 18 for transporting the recording sheet 8 communicating with the opening 17, and a lower end portion of the double-sided sheet transport path 18 opened toward the printer body 1 side. An opening 19 for discharging the paper is provided. In addition, the double-sided unit 16 includes a main cooling fan 1
An exhaust port 20 for exhausting the air flow from the outside is provided.

The recording paper 8 ejected from the paper ejection opening 19 and reintroduced into the printer body 1 passes through the double-sided paper conveyance path 18 and is shown in the state of being turned upside down. An image is transferred to the back surface of the photoconductor drum 3 by the registration roll 10 again by the transport roll, and then fixed by the fixing device 11 and provided as a recording medium discharge unit provided on the upper portion of the printer body 1 as a discharge tray. The sheet is discharged onto the sheet 13, and the double-sided printing operation ends.

By the way, in this embodiment, the recording medium on which the image is formed is fixed by the heat fixing device, and the recording medium on which the heat fixing is carried out is carried out to the recording medium discharge portion provided on the upper part of the main body of the image forming apparatus. In the ejecting image forming apparatus, a ventilation hole is provided in the bottom portion of the recording medium ejecting portion, which is located in the vicinity of the end portion on the heating and fixing device side.

Further, in this embodiment, a rib for preventing the recording medium from covering the ventilation hole is provided on the surface of the standing wall located at the end of the recording medium discharge portion on the side of the heat fixing device. Has been done.

That is, in this embodiment, as shown in FIG. 2, the discharged paper stack member 21 is disposed at the end of the paper discharge tray 13 as the recording medium discharge unit on the fixing device 11 side. The discharged paper stack member 21 is formed in a shape as shown in FIG. 1, for example, by integrally molding a synthetic resin, and the discharged paper stack member 21 is directly below the exit of the discharge roll 12 of the printer body 1. It is installed in.

As shown in FIG. 1, the discharged paper stack member 21 is provided with a standing plate portion 2 provided in a substantially vertical standing state.
2, a horizontal plate portion 23 integrally provided so as to be substantially orthogonal to the upright plate portion 22, and both end portions in the longitudinal direction so as to connect the upright plate portion 22 and the horizontal plate portion 23. And side plates 24 that are respectively provided upright.
The upright plate portion 22 is formed at a height that does not hinder the recording sheet 8 discharged by the discharge roll 12 from passing through, and its upper end does not interfere with a plurality of divided discharge rolls or the like. As described above, the cutout portion 25 is provided at a position corresponding to each discharge roll 12. Further, as shown in FIG. 5, on the outer surface of the upright plate portion 22, first ribs 26 protruding in the vertical direction are provided at a constant interval over substantially the entire length, and the upright plate portion 22 is provided. Two second ribs 27, each having an L-shaped cross section, are provided close to the central portion of the outer surface of the portion 22 and one at each of both ends, and are higher than the first ribs 26 across the horizontal plate portion 23. It is projected.

Further, in the horizontal plate portion 23 of the discharged paper stack member 21, as shown in FIGS. 1 and 5, ventilation holes 28 opened in a rectangular shape on the surface of the horizontal plate portion 23 are substantially constant. A plurality of holes are provided at intervals. These plural ventilation holes 28
Does not directly open to the back surface side of the horizontal plate portion 23, but on the back surface side of the horizontal plate portion 23, as shown in FIG. 6, there is a receiving portion 29 that covers each vent hole 28 in a dome shape. It is provided. The receiving portion 29 includes a pair of leg portions 30 and 31 projecting downward and a shield portion 32 connecting the pair of leg portions 30 and 31 at both ends of the vent hole 28 in the sheet discharging direction. Both side surfaces of the receiving portion 29 orthogonal to the paper discharge direction are opened as they are. By doing so, light enters the inside of the printer body 1 through the ventilation hole 28 opened at the upper end portion of the printer body 1, and the photoconductor drum 3 is unintentionally exposed to light, and foreign matter such as dust and dust is generated in the printer. Outside air can be introduced into the inside of the printer body 1 through the ventilation hole 28 and the opening 33 while preventing the invasion into the inside of the body 1 by the shielding portion 32 of the receiving portion 29.

The inner surface 28a of the vent hole 28 provided in the horizontal plate portion 23 on the fixing device 11 side is formed in a slightly inclined state as shown in FIG. The airflow A that is formed downward through the ventilation holes 28a is formed downward along the surface of the upright plate portion 22, but is slightly raised in the state where it has moved to the lower end portion of the upright plate portion 22. It is set to face away from the plate portion 22.

Further, as shown in FIG. 5, the horizontal plate portion 23 of the discharge paper stack member 21 is provided on the side of the ventilation hole.
The third rib 34 is formed in a tapered shape so as to be higher toward the upright plate portion 22.

Further, in this embodiment, the recording medium on which the image is formed is fixed by the heat fixing device, and
The recording medium on which the heat is fixed is discharged to the recording medium discharge section provided on the upper part of the image forming apparatus main body, and at the side of the image forming apparatus main body, one side is formed when images are formed on both sides of the recording medium. An image forming apparatus having a duplex unit for transporting a recording medium on which an image is formed to an image forming unit again, for transporting the recording medium from the image forming apparatus main body to the duplex unit inside the duplex unit. The auxiliary cooling fan is installed in the vicinity of the opening.

Further, in this embodiment, an inflow prevention member for preventing the inflow of air from the inside of the double-sided unit to the auxiliary cooling fan is provided.

That is, in this embodiment, as shown in FIGS. 2 and 3, inside the duplex unit 16,
The auxiliary cooling fan 3 is provided near the opening 17 for conveying the recording paper 8 from the printer body 1 to the duplex unit 16.
5 are installed. The auxiliary cooling fan 35 is smaller than the main cooling fan 14, and has an opening 17 for conveying the recording paper 8 from the printer body 1 to the duplex unit 16 and the vicinity of the fixing device 11 in the printer body 1. The heat of is discharged to the outside for cooling.

Inside the double-sided unit 16,
Backflow prevention ribs 36 and 37 as inflow prevention members that prevent air from flowing into the auxiliary cooling fan 35 from the inside of the double-sided unit 16 are provided in the upper portion of the double-sided unit 16.
They are arranged in two stages vertically so as to face each other in the horizontal direction with the sheet conveyance path 18 for both sides interposed. Further, a backflow prevention rib 38 as an inflow prevention member for preventing air from flowing into the auxiliary cooling fan 35 from the inside of the double-sided unit 16 is provided below the auxiliary cooling fan 35.

These backflow preventing ribs 36 to 38 are provided for the airflow A caused by the auxiliary cooling fan 35.
By narrowing the passage of No. 2, the Bernoulli's theorem is used to increase the flow velocity of the air flow A and form a pressure difference, so that the air is prevented from flowing into the auxiliary cooling fan 35 from the inside of the double-sided unit 16. It serves to prevent it.

With the above-described structure, in the printer according to this embodiment, the temperature rise of the member which may be touched by the user in the vicinity of the fixing device can be performed without sacrificing the fixing property in the following manner. It is possible to reduce.

That is, in the printer according to this embodiment, as shown in FIGS. 2 and 3, the recording paper 8 on which the toner image is formed by the image forming unit 2 and which is fixed by the fixing device 11 is When the sheet is discharged onto the sheet discharge tray 13 provided on the upper part of the printer body 1, the main cooling fan 14 is synchronized with the printing operation by the printer.
And the auxiliary cooling fan 35 is operated.

Inside the printer body 1, the heat discharged from the fixing device 11 is attached to the side surface of the printer body 1 by the airflow A formed by the main cooling fan 14, as shown in FIG. It is discharged to the outside through the double-sided unit 16 thus formed.

At this time, the airflow A formed by the main cooling fan 14 passes near the fixing device 11, but an opening for discharging the recording paper 8 from the discharging roll 12 is provided near the fixing device 11. And a ventilation hole 28 opened at the bottom near the end of the discharge tray 13 on the fixing device 11 side. As shown in FIG. 8, the upright plate portion of the discharged paper stack member 21 provided with the ventilation hole 28 extends from the ventilation hole 28 opened at the bottom of the discharge tray 13 near the end on the fixing device 11 side. Airflow A flowing along 22 flows in. Therefore, the paper is discharged onto the paper discharge tray 13 and its rear end portion is the horizontal plate portion 2 of the paper discharge stack member 21.
Even if a large number of recording papers 8 are stacked on the sheet 3, the air holes 28 are not blocked by the recording papers 8. Therefore, the air flow A flowing in from the air holes 28 efficiently closes the vicinity of the fixing device 11. Can be cooled well,
The standing plate portion 22 of the discharged paper stack member 21 is fixed to the fixing device 11.
It can prevent being heated to a high temperature.
Further, the trailing edge of the recording paper 8 is sent downward by the airflow A flowing along the upright plate portion 22 of the discharge paper stack member 21 and flowing into the ventilation hole 28, and the stack of the recording paper 8 is stacked. Be promoted.

Further, inside the double-sided unit 16, as shown in FIGS. 2 and 3, an auxiliary cooling fan is provided in the vicinity of the opening 17 for conveying the recording paper 8 from the printer body 1 to the double-sided unit 16. Since 35 is installed, the heat in the vicinity of the fixing device 11 can be discharged to the outside by the auxiliary cooling fan 35 through the opening 17, and from this point as well, the vicinity of the fixing device 11 can be efficiently provided. The standing plate portion 22 of the discharged paper stack member 21 that can be cooled
It is possible to prevent the fixing device 11 from being heated to a high temperature.

[0043]

As described above, according to the present invention,
It is possible to provide an image forming apparatus capable of reducing the temperature rise of a member which may be touched by the user near the fixing device without sacrificing the fixing property.

[Brief description of drawings]

FIG. 1 is a perspective view showing a discharged paper stack member which is a main part of an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram showing a printer as an image forming apparatus according to the first embodiment of the present invention.

FIG. 3 is a configuration diagram showing a printer as an image forming apparatus according to the first embodiment of the present invention.

FIG. 4 is a schematic configuration diagram showing an image forming unit.

FIG. 5 is an enlarged perspective view showing a main part of a discharged paper stack member.

FIG. 6 is an enlarged perspective view of a main part of the discharged paper stack member as seen from below.

FIG. 7 is an explanatory diagram showing an operation of the image forming apparatus according to the first embodiment of the present invention.

FIG. 8 is an explanatory diagram showing an operation of the image forming apparatus according to the first embodiment of the present invention.

FIG. 9 is an external perspective view showing a conventional image forming apparatus.

FIG. 10 is a configuration diagram showing a main part of a conventional image forming apparatus.

FIG. 11 is a schematic configuration diagram showing a conventional image forming apparatus.

[Explanation of symbols]

1: printer body, 8: recording paper, 11: fixing device, 1
3: discharge tray, 21: discharge stack member, 22: standing plate part, 23: horizontal plate part, 28: vent hole.

Claims (4)

[Claims] 1. An image forming apparatus for fixing a recording medium on which an image is formed by a heat fixing device and discharging the heat fixed recording medium to a recording medium discharging section provided on an upper portion of an image forming apparatus main body. An image forming apparatus, characterized in that a ventilation hole is provided in a bottom portion of the recording medium discharge portion, which is located in the vicinity of an end portion of the recording medium discharge portion on the heat fixing device side. 2. The rib for preventing the recording medium from covering the ventilation hole is provided on the surface of the standing wall located at the end of the recording medium discharge portion on the side of the heat fixing device. The image forming apparatus described. 3. A recording medium on which an image has been formed is fixed by a heat fixing device, and the recording medium on which the heat has been fixed is discharged to a recording medium discharge section provided at the top of the image forming apparatus main body, and image formation is performed. In an image forming apparatus having a double-sided unit for transporting a recording medium having an image formed on one side thereof to the image forming unit again, when forming an image on both sides of the recording medium, on the side of the apparatus main body, Inside the main body of the image forming apparatus, a main cooling fan that discharges heat from the heat fixing device from the side surface of the double-sided unit side is installed, and inside the double-sided unit, the main body is recorded from the main body of the image forming apparatus to the double-sided unit. An image forming apparatus, wherein an auxiliary cooling fan is installed in the vicinity of an opening for conveying a medium. 4. The image forming apparatus according to claim 3, further comprising an inflow prevention member provided above the duplex unit to prevent air in the duplex unit from flowing into the auxiliary cooling fan.