JP2001144890A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the costs of a rack for installing a scanner unit and to exhaust sufficiently heated air from an image forming device despite of arranging a fan for forcedly exhausting heated air by efficiently discharging heat from a heat fixing part. SOLUTION: This image forming device obtained by arranging an ejecting paper placing part over an image forming part and the image forming part over the ejecting paper placing part is provided with the image forming part, a connection pat for integrally fixing the image forming part, a blowoff opening which attains ventilation between the outside and the inside of the device body and is provided as the connection part, and a tilting plate for leading air heated by the heat fixing part to the blowoff opening.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus, and more particularly, to heat discharge of an image forming apparatus for thermally fixing a toner image.

[0002]

2. Description of the Related Art In recent years, digital copiers having a paper discharge tray disposed above a print engine and a scanner unit disposed above the paper discharge tray have appeared. In this digital copying machine, a scanner unit (image reading unit) obtains image data from a document, and a print engine unit forms a toner image based on the image data on a photoreceptor surface by an electrophotographic process, and the toner image is used as a recording material. Transcribe. The toner image transferred to the recording material is fixed on the recording material by a heat fixing device or the like, and is discharged to a discharge tray. When this digital copying machine is installed, the paper ejection tray does not protrude from the area of the bottom surface of the apparatus main body, so that the space saving of the image forming apparatus is realized.

Although the digital copying machine has a device capable of separating a scanner unit and a printer engine,
A frame for installing the scanner unit on the print engine is required, which increases costs.

The above-described digital copying machine sometimes employs an internal layout in which a heat fixing device is arranged above a printer engine. 2. Description of the Related Art An example of a copier or the like that forms an image by an electrophotographic process, which includes a heat fixing device that heat-fixes a toner image onto a transfer material surface such as recording paper, is very well known. The heat fixing device is provided with a heating unit such as a heat roller, which reaches several hundred degrees, and heats not only recording paper and toner but also surrounding air and members by radiation and convection of heated air. Therefore, a fan for forcibly exhausting heated air to the outside of the apparatus main body of the image forming apparatus is employed. If no fan is provided, that is, if the heated air is not forcibly exhausted, various adverse effects occur due to permanent deformation and deterioration of the resin member, expansion of the metal member, and the like.

[0005]

SUMMARY OF THE INVENTION Accordingly, the present invention reduces the cost of a gantry on which an image reading unit is installed, and
It is an object of the present invention to efficiently exhaust air heated in a heat fixing unit and eliminate the need for disposing a fan for forced exhaust.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is as set forth in claim 1.
The problem can be solved by the image forming apparatus described in (1). That is, claim 1
The image forming apparatus described in (1) performs a photoelectric conversion by scanning a document, an image reading unit that outputs image data corresponding to image information read from the document, and an image reading unit formed on an image carrier based on the image data. An image forming unit for transferring the toner image to the recording material; a heat fixing unit for fixing the toner image transferred to the recording material to the recording material; and a discharging unit for placing the recording material discharged from the heat fixing unit. An image forming apparatus, comprising: a paper placement unit; and the paper ejection placement unit above the image formation unit; and the image reading unit arranged above the paper ejection placement unit. A connecting portion for integrally fixing the reading portion, an air outlet provided in the connecting portion for allowing the outside and the inside of the apparatus main body to be ventilated, and an inclined plate for guiding the air heated by the heat fixing portion to the air outlet. It is characterized by having.

In this image forming apparatus, the discharge tray is disposed above the image forming part, and the image reading part is disposed above the discharge tray. The image reading unit is integrally fixed. Therefore, since there is no need to provide a separate stand for mounting the image reading unit,
Cost can be reduced. In addition, since the inclined plate is efficiently heated by the heat fixing unit and rises by being guided to the air outlet provided in the connection unit, the air is exhausted. Can be reduced.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a digital image forming apparatus (hereinafter, referred to as a digital image forming apparatus).
FIG. 1 is a schematic diagram illustrating a configuration of an image forming apparatus 1).

In FIG. 1, an image forming apparatus 1 includes an automatic document feeder (ADF) A, an image reading unit B for reading an image of a document fed by the automatic document feeder A, and a read document image. Processing substrate C for processing
And a writing unit 12 for writing on an image carrier 10 composed of a photosensitive drum according to data after image processing.
And a developing unit 1 composed of a magnetic brush type developing device, and a writing unit D including
6, transfer electrode 18, separation electrode 20, cleaning means 2
And a plurality of paper storage means (hereinafter referred to as a sheet feed tray or simply a tray) for storing a recording material (hereinafter referred to as a sheet) P for image formation such as recording paper. , Trays) 22 and 24.

The automatic document feeder A includes a document table 26
And a document transport processing unit 28 including a roller group including a roller R1 and switching means for appropriately switching a document movement path (no reference symbol).

An image reading section B is located under a top glass G for placing a document thereon, and can reciprocate while maintaining an optical path length.
The writing unit D includes three mirror units 30, 31, a fixed imaging lens (hereinafter, simply referred to as a lens) 33, a line-shaped image sensor (hereinafter, referred to as a CCD) 35, and the like.
It comprises a laser light source 40, a polygon mirror (polarizer) 42 and the like.

The automatic document feeder A has a difference in configuration from the conventional automatic document feeder, but the principle itself is well known, and an image reading section B, a writing section D, an image processing board C, and a toner image forming apparatus. An image forming apparatus and an image forming process provided with a portion E (a toner image is formed on the image carrier 10 and the toner image is transferred onto a sheet) are well known. It will be done simply.

When viewed from the moving direction of the sheet P, R10 shown on the front side of the transfer electrode 18 is a registration roller, and H shown on the downstream side of the separation electrode 20 is a thermal fixing device.

The heat fixing unit H is an example of the heat fixing unit of the present invention. In the embodiment, a heat roller H1 as a heat source and a pressure roller H2 that is driven to rotate while being pressed against the heat roller H1 are main components. It is configured to be driven and rotated by a drive motor (not shown). Heat roller H1
Is formed on the outer peripheral surface of the core metal by forming a resistance heating layer made of a low melting point glass containing a conductive filler in a cylindrical core metal made of an aluminum alloy, an insulating layer made of a heat-resistant insulating material such as polyimide, and PFA ( Tetrafluoroethylene /
A heat-resistant release layer such as a perfluoroalkylvinylether copolymer) or a tetrafluoroethylene resin, and the heat generated by the resistance heating layer reaches a high temperature of several hundred degrees and heats the toner image on the sheet P by the conduction heat. Then, the sheet is thermally fixed on a sheet P which is an example of a recording material.

Further, Z is a cleaning means for removing toner and paper dust adhering to the surface of the heat roller H1, and has a cleaning web provided so as to be wound up as a main element.

In the above configuration, the process of forming a toner image on the image carrier 10, transferring and fixing the toner image on a sheet, and then discharging the toner image to a paper discharge tray is as follows.

One of the originals (not shown) placed on the original placing table 26 is transported in the original transport processing unit 28, and the lamp L provided in the image reading unit B while passing under the roller R1.
Scanning exposure is performed.

The reflected light from the original passes through the mirror units 30 and 31 and the lens 33 at a fixed position, and
An image is formed on D and photoelectrically converted. The process from scanning exposure to photoelectric conversion is called reading.

The image information read by the image reading unit B is
The image is processed by the image processing board C, encoded, compressed, and stored as image data in a memory provided on the image processing board C.

The image data is called from a memory and expanded in accordance with the execution of image formation, and the laser light source 40 in the writing section D is driven in accordance with the image data to expose the image carrier 10. .

Prior to the exposure, the image carrier 10 rotating in the direction of the arrow (counterclockwise) is given a predetermined surface potential by the corona discharge action of the charging electrode 14. Is reduced according to the exposure amount, and as a result, an electrostatic latent image corresponding to the image information is formed on the image carrier 10.

The electrostatic latent image is reversely developed by the developing means 16 to be a visible image (toner image).

On the other hand, before the leading end of the toner image on the image carrier 10 reaches the transfer area, for example, one sheet P in the sheet feed tray 22 is fed and conveyed to the registration roller R1.
It reaches 0 and the tip is regulated.

The sheet P whose front end is regulated is placed on the image carrier 10.
The toner image formed on the surface of the image carrier 10, that is, the image area on the image carrier 10, is conveyed toward the transfer area by the registration roller R10 that starts rotating in synchronization.

In the transfer area, the toner image on the image carrier 10 is transferred onto the sheet P by the action of the transfer electric field of the transfer electrode 18, and the sheet P is separated from the image carrier 10 by the action of the separation electrode 20. Is done.

Thereafter, the pressure and heat of the heat fixing device H are
The toner powder forming the toner image is melted and fixed on the sheet P, and the sheet P is transferred via a paper discharge path 78 and a paper discharge roller 79 onto a paper discharge tray T which is an example of a paper discharge mounting portion of the present invention. Is discharged to

When toner images are formed (fixed) on both sides of one sheet P, the sheet P having the toner image fixed on one side is guided to the branch guide 90 and sent to the reverse conveyance path 80. The sheet P that has passed through the reverse conveyance path 80 passes through the switchback conveyance path 81 and is again registered with the registration roller R1.
The toner image is transferred to the discharge tray T after the toner image is transferred to the remaining surface by the toner image forming unit E and the toner image is fixed by the heat fixing unit H.

The paper discharge guide plates 781 and 782 are connected to the paper discharge passage 7.
8 and guide plates 801 and 802 forming the reversing conveyance path 80, which are fixed at predetermined intervals.

The image forming section 100 including the image processing board C, the writing section D, the toner image forming section E and the like is an example of the image forming section of the present invention, and forms a so-called printer engine together with the heat fixing device H. And outputs a sheet P on which a toner image is formed by digital electrophotography based on the input (read) image data.

The paper output tray T is an example of the paper output tray of the present invention, and is laid out on the image forming unit 100. The sheet P is conveyed from the lower side of the toner image forming section E to the upper side in the figure, and is consequently placed on a sheet discharge tray T disposed immediately above the image forming section 100. When a plurality of sheets P are output, the output tray T
It is placed on top of it.

The scanner section 200 comprising the automatic document feeder A and the image reading section B constitutes a so-called scanner unit, and outputs image data to the image forming section 100 as a printer engine. The connecting unit 300 includes a housing frame having four vertical surfaces formed of sheet metal, supports the scanner unit 200 together with the support columns 310 and the like, and further includes a resin member partially shared with the image forming unit 100 and the scanner unit 200. (Not shown). With these, the scanner unit 200
Are integrated with the image forming unit 100 by the connecting unit 300.

Inside the housing frame, a part of the reverse conveyance path 80, the branch guide 90, the paper discharge path 78, and the paper discharge roller 7
9 are arranged.

In the apparatus main body of the image forming apparatus 1, the surrounding air is heated by the heat generated by the heat roller H1, and an air current is generated by a convection phenomenon.

The connecting portion 300 is disposed so as to cover the upper part of the image forming part 100, more specifically, the upper part of the heat fixing device H. Therefore, the airflow that has passed through the inside of the apparatus main body due to convection finally flows into the internal space of the connecting portion 300.

The inclined plate 320 is a sheet metal that covers directly above the heat roller H1 and whose upper edge Pb is inclined rightward in the figure, and is located at a position where the airflow generated by the convection flows to the right side in the figure. It is arranged. In the present embodiment, the heated air rises due to the generated airflow and rises around the sheet discharge path 78 and the reverse conveyance path 80 above the thermal fixing device H,
Further, the air passes through the periphery of the paper discharge path 78 and the reverse conveyance path 80, flows along the inclined plate 320, and is exhausted from the outlet 305 to the outside of the apparatus main body. The inclined plate 320 is not limited to metal as long as it is a heat-resistant material, and any material such as a resin may be used. In addition, any shape may be used as long as the generated airflow is exhausted to the outside of the apparatus main body. For example, a reinforcing rib or the like may be provided.

The outlet 305 is an opening provided on the right side of the housing frame in the figure. The exterior resin member (not shown) is provided with a louver (described later) at a portion corresponding to the outlet 305. I have. The outlet 305 is provided at the uppermost part of the connection part 300. As described above, the heated air that has passed through the inside of the apparatus main body and flowed into the inside of the connecting portion 300 is
It continues to rise inside. Since the outlet 305 is provided at the top of the connecting part 300, the connecting part 300
The heated air that has flowed into the space is efficiently exhausted without remaining in the internal space of the connecting portion 300.

FIG. 2 is a schematic diagram showing a part of the configuration of the image forming apparatus 1 as viewed from the direction of the arrow W in FIG. In FIG. 2, the inclined plate 320, the heat roller H1, the discharge guide plate 78
1, a branch guide 90 is shown, and other members constituting the image forming apparatus 1 are omitted.

The axis S1 shown by a dashed line is a heat roller H
1 is a rotary shaft, and a drive motor, a shaft, and the like are schematically illustrated by omitting them. Heat generation width WH is heat roller H1
2 shows the length of the range in which heat is actually generated, which corresponds to the width of the resistance heating layer, and is an example of the axial length of the heat roller in the present invention. For example, in the case of an image forming apparatus employing a heat fixing unit of a type in which a metal roll is heated by radiant heat of a built-in heat lamp or the like, the width of the metal roll is the axial length of the heat roller.

The branch guide 90 has a large number of branch claws that rotate in a lump, and the airflow freely rises between the branch claws.

The paper discharge guide plate 781 is a member made of resin, and regulates a passage path of the sheet P sent out from the thermal fixing device H by conveyance so that the paper P reaches the paper discharge roller 79.

The discharge guide plate 781 is provided with a vent hole 781a through which an air flow passes (a part is omitted).
A plurality of ventilation holes 781a are provided in the paper discharge guide plate 781 over a range that substantially matches the heat generation width WH. In the present embodiment, an example is shown in which the ventilation holes 781a are rectangular openings, but the shape, number, and arrangement of the ventilation holes are arbitrary as long as the sheet P can be smoothly conveyed. For example, the shape may be any of a long groove, a round hole, an ellipse, and the like in the sheet P conveying direction. If you do, you can make it even more free.

A part of the paper discharge guide plate 781, which is indicated by a chain line in the drawing, is a part hidden by the inclined plate 320.

Although not shown, the discharge guide plate 782 and the reverse guide plates 801 and 802 are provided with the same ventilation holes as the discharge guide plate 781 in addition to the discharge guide plate 781, so that It does not block the airflow passing through.

In the inclined plate 320, the lower edge Pa is inclined backward in the figure, and the upper edge Pb is inclined forward in the figure (see FIG. 1). The inside of the connecting portion 300 is raised, and the inclined plate 3
The airflow hindered by the upward movement by the inclined plate 20
Is led to the outlet 305 along the inclination of
Is exhausted to the outside of the apparatus body.

The width WP of the inclined plate 320 substantially coincides with the heat generation width WH of the heat roller H1 so as to sufficiently obstruct the flow path of the airflow that rises in the internal space of the connecting portion 300, and is strictly made slightly longer. The airflow is made difficult to escape. However, the escape of the airflow means that the airflow flows in a direction other than the outlet 305. It is more preferable that both ends of the inclined plate 320 are bent to have a U-shaped cross-sectional shape, since it becomes more difficult for airflow to escape. Further, it is more preferable to fix both end edges of the inclined plate 320 to the inner surface of the housing frame, since the airflow does not escape. The fixing of the inclined plate 320 may be performed by screwing, bonding, welding, or any other method.

The outlet 305 is provided on the right side of the connecting portion 300 in FIG. If the air outlet 305 is provided on the bottom surface of the apparatus main body, there is a problem that the air flow is not naturally exhausted and stays inside the apparatus main body. Part B
And there is a problem in that the reading operation of the image reading unit B may be hindered by heat or water vapor evaporated from the sheet P. If it is the side surface of the apparatus main body, the air flow is naturally exhausted on any of the four surfaces, which is good.

Next, a description will be given with reference to a perspective view of the vicinity of the air outlet 305 shown in FIG. In the outlet 305, vertically long louvers 311 are arranged at equal intervals over the entire width.
An outlet 305 is constituted by the whole of the plurality of outlets 312 separated by the louver 311. In FIG. 3, only two louvers 311 and two outlets 312 are denoted by reference numerals because of complexity, but in the example of FIG.
Louvers and 11 outlets 312.
The opening width WL of the outlet 305 is the heat generation width WH (see FIG. 2).
Since the flow path is not substantially constricted, exhaust of heated air is not hindered. Further, the airflow may be generated over the entire width of the heat generation width WH. The connecting portion 300 (see FIG. 1) has a large volume separated by a housing frame,
The air flow is exhausted from the opening of the outlet 305 while the flow path is not restricted, and the position of both ends of the opening of the outlet 305 passes through one end of the heat roller H1. Because it is on two planes perpendicular to the axis of rotation, it is very efficiently evacuated. The outlet 305
Even if the positions of both ends of the opening are not on the above-mentioned two planes, they can be exhausted sufficiently efficiently if they are located at substantially the same position.

In the image forming apparatus 1 described above, since the connecting portion 300 is provided above the image forming portion 100, the heated air can easily flow in, and the outlet 305 can be surely provided.
Can be led to.

Further, since the connecting portion 300 is provided at a position covering the upper portion of the heat fixing device H which is an example of the heat fixing portion,
Heated air can flow more easily into the internal space of the connecting portion 300 than when the connecting portion 300 is simply provided above the image forming portion, and can be guided to the outlet 305 reliably.

Since the outlet 305 is provided at the uppermost part of the connecting part 300, the heated air flowing into the internal space of the connecting part 300 can be reliably exhausted from the outlet 305.

Further, since the inclined plate 320 is provided at a position covering the upper part of the heat fixing unit H which is an example of the heat fixing unit, it is possible to reliably guide the heated air to the outlet 305 provided on the side surface. it can.

The length of the inclined plate 320 in the longitudinal direction is substantially equal to the length of the heat roller H1 in the axial direction.
Since the first axial direction and the longitudinal direction are arranged in substantially the same direction, the heated air can be more reliably guided to the outlet 305 provided on the side surface without escaping.

Since the outlet 305 is arranged so as to have a width substantially equal to the length of the inclined plate 320 in the longitudinal direction,
The heated air can be efficiently exhausted from the outlet 305 without causing airflow resistance.

Further, since the outlet 305 is provided with the louver 311, it is possible to prevent an accident such as an accidental insertion of the user's hand.

Further, since the air outlet 305 is provided on the side surface of the connecting portion 300, the problem associated with the exhaust can be avoided.

[0057]

According to the image forming apparatus of the present invention,
Since there is no need to provide a frame on which the image reading unit is placed, and a fan for forcibly exhausting heated air is not required,
Cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a configuration of a digital image forming apparatus according to the present invention.

FIG. 2 is a schematic diagram illustrating a part of the configuration of the image forming apparatus viewed from a direction of an arrow W in FIG. 1;

FIG. 3 is a perspective view of the vicinity of an air outlet.

[Description of Signs] 1 Image forming apparatus 10 Image carrier 305 Air outlet 311 Louver 320 Inclined plate B Image reading unit E Toner image forming unit H Thermal fixing unit 100 Image forming unit T Paper ejection tray

Continued on the front page F term (reference) 2H027 JA11 JB12 JB13 JB15 JC08 2H033 AA41 BA29 2H071 DA12 EA00 EA04 5C062 AB22 AB29 AD00 AD06 BA07 9A001 HH34 JJ35 KK42

Claims (9)

[Claims] An image reading unit that scans a document to perform photoelectric conversion and outputs image data corresponding to image information read from the document; and a toner image formed on an image carrier based on the image data. An image forming unit for transferring the recording material to a recording material; a heat fixing unit for fixing the toner image transferred to the recording material to the recording material; and a discharge tray for placing the recording material discharged from the heat fixing unit And an image forming apparatus, wherein the discharge tray is disposed above the image forming unit, and the image reading unit is disposed above the discharge tray. A connection portion for fixing integrally, an air outlet provided in the connection portion for allowing the outside and the inside of the apparatus main body to be ventilated, and an inclined plate for guiding the air heated by the heat fixing portion to the air outlet. An image forming apparatus characterized in that: 2. The image forming apparatus according to claim 1, wherein the connecting unit is provided above the image forming unit. 3. The image forming apparatus according to claim 2, wherein the connecting portion is provided at a position covering the heat fixing portion. 4. The image forming apparatus according to claim 1, wherein the air outlet is provided at an uppermost portion of the connecting portion. 5. The image forming apparatus according to claim 1, wherein the inclined plate is provided at a position covering an upper part of the heat fixing unit. 6. The heat fixing unit includes a heat roller, and the inclined plate has a longitudinal length substantially equal to an axial length of the heat roller, and an axial direction of the heat roller substantially coincides with the longitudinal direction. The image forming apparatus according to claim 1, wherein the image forming apparatus is arranged in a direction. 7. The image forming apparatus according to claim 1, wherein the outlet is disposed so as to correspond to a width substantially equal to a length of the inclined plate in a longitudinal direction. apparatus. 8. The image forming apparatus according to claim 1, wherein the outlet comprises a louver. 9. The air outlet according to claim 1, wherein the air outlet is provided on a side surface of the connecting portion.
Or the image forming apparatus according to 8.