JP2001022237A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device where water vapor is not discharged in the case of fixing without causing cost rising. SOLUTION: This image forming device is equipped with a transfer material carrying path on a downstream side from a fixing means. Then, it is provided with a movable carrying guide member 12 located at a position where the member 12 closes the carrying path when the transfer material is not carried in the carrying path L, and moving from the position where it closes the carrying path by the contact pressure of the transfer material when the transfer material is carried in the carrying path and allowing the carrying of the transfer material.

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 for a computer or a copying machine, and more particularly to a structure of a discharge unit.

[0002]

2. Description of the Related Art Conventionally, an image forming apparatus using an electrophotographic system forms an electrostatic latent image on a surface of a photosensitive drum as an image carrier, and forms the electrostatic latent image on the photosensitive drum with a developer. Developed with a toner or the like to make it a visible image, the developed image is transferred to a transfer material by a transfer device, the image is carried on the transfer material, and the toner image on the transfer material is pressed by a fixing device using pressure, heat, etc. To fix. The fixed transfer material is
It is discharged outside the device through the discharge path. The discharge path is provided with a plurality of ribs in order to reduce the contact resistance with the transfer material, and the discharge path is often integrated with the back side of the external cover because it is close to the external cover. Ribs,
And a rib provided on the main body side.

[0003] Further, since the outer cover may be opened and closed by a user for jam processing or the like, a detecting means for detecting opening and closing is provided, and a detecting means for detecting a jam in a discharge path is provided. It is often provided separately.

[0004]

However, with the downsizing of the main body of the apparatus, a discharge path is provided in the vertical direction immediately after the downstream side of the fixing device, and when a full-color, high-print image is fixed, it is included in the toner. The residual water that evaporates into -gases and becomes water vapor, which is discharged through the discharge path to the outside of the device and may cause a user to think that a fire has occurred, and to make this water vapor inconspicuous. Had to provide fans on both sides of the discharge path to disperse steam.

The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide an image forming apparatus in which water vapor is not discharged at the time of fixing without increasing the cost. is there.

In addition to the above object, the detection means for detecting the opening and closing of the outer cover and the detection means for detecting the jam of the transfer material on the conveyance path are shared, thereby reducing the number of parts and reducing the cost. It is to plan.

[0007]

According to a first aspect of the present invention, there is provided a fixing device for fixing an image by heating a transfer material on which an unfixed image is formed, and fixing the image. And a transfer path for a transfer material downstream of the means, wherein the transfer path is located at a position closing the transfer path when the transfer material is not transferred along the transfer path, and the transfer path is transferred to the transfer path. A movable conveyance guide is provided, which is moved by a contact pressure of the transfer material from a position where the transfer path is closed when the material is conveyed, and which allows conveyance of the transfer material.

In the present invention, the transport guide is located in the direction to close the transport path, and the transport guide and the transfer material are in contact with each other even during the transport of the transfer material, so that the rising steam hits the transport guide and becomes water droplets. It is not discharged out of the device.

The invention according to a second aspect is characterized in that the transport guide is swingable with the upstream side of the transport path as a fulcrum. With this configuration, the transfer guide is smoothly moved by the transfer material.

The invention according to a third aspect is characterized in that the transport guide is configured to return to a position where the transport path is closed by the weight of the transport guide after the transfer material passes through the transport path. This simplifies the configuration.

The invention according to claim 4 is characterized in that at least a part of the transport guide is formed by a low friction sliding member. In this way, even if the conveyance guide is in contact, the contact friction is reduced and the transfer material is smoothly conveyed.

The invention according to claim 5 is characterized in that the sliding member has a friction coefficient of 0.16 or less. If the friction coefficient is set to such a degree, it is possible to reliably convey.

The invention according to claim 6 is characterized in that a roller rotatable by the contact of the transfer material is provided at the most downstream side of the transfer guide where the transfer material contacts. If you use rollers,
The rollers roll on the transfer material, and the transfer material is transported more smoothly.

The invention according to claim 7 is characterized in that the rollers are formed of a low friction resin material such as fluorine or tetrafluoroethylene resin. If you do this,
Even if the rollers slide on the surface of the transfer material, the frictional resistance is small and the transfer material can be smoothly conveyed.

The invention according to claim 8 is a detecting means for enabling the transport guide to be moved by opening and closing a cover forming the exterior of the apparatus main body, and detecting that the cover is closed by the movement of the transport guide. Wherein the detecting means also functions as means for detecting the movement of the transfer guide when the transfer material passes through the transfer path and detecting the passage of the transfer material. As described above, by detecting the opening / closing of the outer cover and detecting that the transfer material has passed through the transport path by the common detection unit, it is possible to reduce the number of components and the cost.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on illustrated embodiments. 1 to 4 show an image forming apparatus according to an embodiment of the present invention. First,
The overall configuration of the image forming apparatus will be described with reference to FIG. FIG. 4 is a schematic configuration diagram of an image forming apparatus using an electrophotographic method according to the present embodiment. This image forming apparatus A
Is a laser printer capable of forming a full-color image of four colors, and a fixing device as a fixing unit for fixing an image by heating a transfer material S on which an unfixed image visualized by a toner as a developer is formed. 8 and a transfer material transport path L downstream of the fixing device 8.

The image forming apparatus A includes a photosensitive drum 1 which is a drum type electrophotographic photosensitive member as a first image carrier. The photosensitive drum 1 is driven by driving means (not shown).
For example, it is driven to rotate counterclockwise.

A charging device 2 for uniformly charging the surface of the photosensitive drum 1 in order in accordance with the rotation direction of the photosensitive drum 1 around the photosensitive drum 1 is irradiated with a laser beam based on image information. An exposure device 3 for forming an electrostatic latent image, a developing device 4 for applying toner as a developer to the electrostatic latent image and developing it as a toner image, a second image carrier on which a toner image on the photosensitive drum 1 is primarily transferred A transfer unit 5 as a body, a cleaning device 6 for removing transfer residual toner remaining on the surface of the photosensitive drum 1 after the primary transfer, and the like are provided.

The developing device 4 for developing the electrostatic latent image on the photosensitive drum 1 has four developer accommodating portions 4BK, 4Y, 4M, and 4C for accommodating four color toners. , 4Y, 4M, and 4C are arranged concentrically around the rotation center 4a. Each developer container 4BK, 4
Y, 4M, and 4C are provided with a developer carrying roller 4b that carries the toner as a developer on the surface and faces the photosensitive drum 1 when the developer accommodating portion faces the photosensitive drum 1. The electrostatic latent image on the photosensitive drum 1 can be developed by the developer carrying roller 4b.

The transfer unit 5 as a second image carrier is
After the primary transfer of the toner image on the photosensitive drum 1, the toner image can be secondarily transferred to the surface of the transfer material S fed toward the transfer unit 5. At a predetermined timing, the sheet is conveyed to the transfer unit 5 by the feeding / conveying device.

In the image forming apparatus A, there is provided a fixing device 8 for heating the toner on the transfer material S after the secondary transfer to fix the toner image on the transfer material S. The transfer material S that has passed through the fixing device 8 is discharged to a discharge tray 10 by the transport unit 9. The fixing device 8 heats and pressurizes the transfer material S by passing the transfer material S carrying a toner image between a pair of rotating members, ie, a fixing roller 8a and a pressure roller 8b. A toner image is fixed thereon.

Next, the fixing roller pair 8a, b of the fixing device 8
The configuration of the transfer path L of the transfer material after passing through the nip and the movement of the transfer material S will be described with reference to FIGS.

The transfer path L is located at a position where the transfer path L is closed when the transfer material S is not transferred.
When the transfer material S is conveyed along the transport path L from the position where the transfer material L is closed, the transfer material S is moved by the contact pressure of the transfer material S.
A movable conveyance guide 12 is provided to allow the conveyance. More specifically, the transfer material transport path L is a discharge cover 1 that extends substantially vertically in the up-down direction that constitutes the exterior of the apparatus main body.
1, a lower first guide rib 11a, an upper second guide rib 11b, a movable transport guide 12 facing the first guide rib 11a, and a transport unit 9 facing the upper second guide rib 11b. And a third guide rib 9a.

The transport guide 12 can swing about the fulcrum 12a on the upstream side of the transport path L. In this way, the transfer material S is transferred to the conveyance guide 12 and the fixed guide rib 11.
Guided smoothly during a. The transport guide 12
Is configured to return to a position where the transfer guide L is closed by the weight of the transfer guide 12 after the transfer material S passes through the transfer path L without tilting by 90 degrees or more, and the structure is simplified.

At the most downstream position of the transport guide 12 where the transfer material S comes into contact, a roller 13 that is rotatable by the contact of the transfer material S is provided. If the roller 13 is used, the roller 1
3 rolls on the transfer material S, and the transfer material is transported more smoothly. The roller 13 is formed of a low friction resin material such as fluorine or tetrafluoroethylene resin. In this embodiment, the rollers 13 are formed of PFA, which is a fluororesin, and are rotatably mounted over the width direction of the transfer material S. In this way, even if the roller slides on the surface of the transfer material, the transfer can be carried out smoothly with a small frictional resistance.

The guide rib 11a is provided on an openable and closable discharge cover 11 forming the exterior of the apparatus main body. A photo sensor 14 is provided as detecting means for detecting that the shutter 11 has been closed. Photo sensor 14
Is a conveyance guide 1 when the transfer material S passes through the conveyance path L.
2 also serves as means for detecting the movement of the transfer material S and detecting the passage of the transfer material S.

The discharge cover 11 is openable and closable about a fulcrum 11c at the lower end thereof. A protrusion 12b is provided on the transport guide 12, and the photosensor 14 is opened or shut off by the protrusion 12b. When the discharge cover 11 is open, as shown in FIG. 2, the transport guide 12 swings around the fulcrum 12 a by its own weight, and the protrusion 12 b abuts the transport unit 9. At this time, the protrusion 12
b does not block the optical path of the photo sensor 14, and it is detected that the discharge cover 11 is in the open state.

As shown in FIG. 1, when the ejection cover 11 is closed, the projection 11c of the ejection cover 11 pushes the transport guide 12, and the projection 12b comes to a position where the optical path of the photo sensor 14 is blocked. The closed state is detected. In this state, the main unit can print.
After passing through the nip between the pair of fixing rollers 8a and 8b of the fixing device 8, the transfer material S passes through the space between the guide rib 11a and the conveyance guide 12 along the guide rib 11a, comes into contact with the roller 13, and removes the roller. While rotating, transport guide 1
2 is swung to the position shown in FIG. The sheet is further conveyed by the conveying rollers 15, passes between the guide ribs 9 a and the guide ribs 11 b, and is discharged face down to the discharge tray 10 by the conveying rollers 16.

At this time, the projecting portion 12b of the transport guide 12, which is pressed and oscillated by the transfer material S, is out of the position where the optical path of the photo sensor 14 is blocked as shown in FIG. After that, the transport guide 12 swings by its own weight and returns to the position shown in FIG. 1, and the protrusion 12b returns to the position where the optical path of the photo sensor 14 is blocked. Therefore, if the projection 12b returns to the position where the projection 12b blocks the optical path of the photosensor 14 within a certain period of time, it can be confirmed that the transfer material has passed the transport path L safely. If it does not return to the position where the optical path is blocked, it can be determined that the transfer material S is jammed in the transport path L (jam).

In the above embodiment, the example in which the roller 13 is provided at the tip of the transport guide 12 has been described. However, in another embodiment, the roller 13 is eliminated and the transport guide 12 is removed.
May be formed at least in part by a low-friction sliding member. In this way, even when the transport guide 12 is in contact, the contact friction is reduced and the transfer material S is transported smoothly. The sliding member preferably has a coefficient of friction of 0.16 or less. If the friction coefficient is set to such a degree, it is possible to surely convey. As a sliding member,
It is preferable to mold with a material having good slidability and releasability such as a resin containing fluorine.

[0031]

As described above, according to the present invention, the following effects can be obtained. According to the invention of claim 1,
In an image forming apparatus including a fixing unit that fixes an image by heating a transfer material on which an unfixed image is formed by a heating unit, and a transfer path of a transfer material downstream of the fixing unit, the transfer path may include: When the transfer material is not transported along the transport path, the transfer path is located at a position where the transfer path is closed, and when the transfer material is transported along the transport path, the transfer path is moved by the contact pressure of the transfer material from the position where the transfer path is closed. By providing a movable transport guide that allows the transport of the material, the transport guide is located at a position that closes the transport path, and the transport guide is in contact with the transfer material even during the transfer of the transfer material. Collides with the transport guide and becomes water droplets, and is not discharged out of the apparatus.

According to the second aspect of the present invention, the transport guide can swing about the upstream side of the transport path as a fulcrum, so that the transport guide can smoothly move when the transfer material comes into contact with the transport guide. Moving.

According to the third aspect of the present invention, the transport guide is configured to return to a position where the transport path is closed by the weight of the transport guide after the transfer material passes through the transport path, thereby simplifying the configuration. Be transformed into

According to the fourth aspect of the present invention, at least a part of the conveyance guide is formed of a low-friction sliding member, so that even if the conveyance guide is in contact, the contact friction is reduced. Thus, the transfer material is smoothly transported.

According to the fifth aspect of the invention, since the sliding member has a friction coefficient of 0.16 or less, the transfer material can be transported reliably.

According to the sixth aspect of the present invention, a roller rotatable by the contact of the transfer material is provided at the most downstream side of the transfer guide where the transfer material contacts, so that the roller rolls on the transfer material. The transfer material is transported smoothly.

According to the seventh aspect of the present invention, since the rollers are formed of a low friction resin material such as fluorine or tetrafluoroethylene resin, even if the rollers slide on the surface of the transfer material, the frictional resistance is reduced. Is small and can be transported smoothly.

According to the eighth aspect of the present invention, the transport guide can be moved by opening and closing the cover forming the exterior of the apparatus main body, and the movement of the transport guide detects that the cover has been closed. Providing detection means,
The detection means also detects the movement of the transfer guide when the transfer material passes through the transfer path, and also functions as a means for detecting the passage of the transfer material, thereby detecting opening / closing of the outer cover and transferring the transfer material to the transfer material. By performing the detection of passing through the transport path by the common detection unit, the number of components and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing details of a conveyance path after fixing of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of the exterior cover of FIG. 1 in an open state.

FIG. 3 is an explanatory diagram showing a transfer material conveyance state of FIG. 1;

FIG. 4 is a schematic configuration diagram illustrating an overall configuration of an image forming apparatus having the discharge unit structure of FIG. 1;

[Explanation of symbols]

 8: Fixing device 11: Ejection cover 12: Conveyance guide 12b: Projection 13: Roller 14: Photo sensor (detection means) 11a, 11b, 9a: Guide rib

Claims (8)

[Claims] An image forming apparatus comprising: a fixing unit that heats a transfer material on which an unfixed image is formed to fix an image; and a transfer path of a transfer material downstream of the fixing unit. In the path, when the transfer material is not transported along the transport path, the transfer path is located at a position that closes the transport path, and when the transfer material is transported along the transport path, the transfer path moves from the position that closes the transport path due to the contact pressure of the transfer material. An image forming apparatus provided with a movable conveyance guide that allows conveyance of a transfer material. 2. The transfer guide according to claim 1, wherein the transfer guide is swingable about an upstream side of the transfer path as a fulcrum.
An image forming apparatus according to claim 1. 3. The image according to claim 1, wherein the transport guide is configured to return to a position where the transport path is closed by the weight of the transport guide after the transfer material passes through the transport path. Forming equipment. 4. The image forming apparatus according to claim 1, wherein at least a part of said transport guide is formed by a low friction sliding member. 5. An image forming apparatus according to claim 4, wherein said sliding member has a coefficient of friction of 0.16 or less. 6. The image forming apparatus according to claim 1, wherein a roller rotatable by contact of the transfer material is provided at a most downstream position of the transfer guide where the transfer material contacts. apparatus. 7. An image forming apparatus according to claim 6, wherein said roller is made of a low friction resin material such as fluorine or tetrafluoroethylene resin. And a detecting means for detecting that the cover is closed by a movement of the conveying guide, wherein the detecting means is provided for opening and closing a cover forming an exterior of the apparatus main body. The image according to any one of claims 1 to 7, further comprising a unit that detects movement of the transport guide when the transfer material passes through the transport path and that detects passage of the transfer material. Forming equipment.