JPH05232827A - Toner fixing device for electrophotographic printer - Google Patents

Abstract

PURPOSE:To provide an electrophotographic printer where the miniaturization of the device is achieved and a jam which has conventionally occurred owing to the defective sparation of a transfer body between the paper guide and the toner transfer belt is eliminated. CONSTITUTION:The transfer belt 7 is held by being directly wrapped around a pressure roller 13 which is on the downstream side in the rotating direction of the transfer belt 7 for carrying a body 5 to be transfered and opposite a toner fixing roller 12. On the downstream side in the rotating direction of the transfer belt 7, the body 5 to be transfered on which a toner image 10 is transferred is directly sent between the fixing roller 12 and the pressure roller 13. By eliminating the need for a belt holdling roller, which has been conventionally provided in this part, and, in addition, a paper guide, etc., the miniaturization of the electrophotographic printer can be achieved. At the same time, by making the paper guide unnecessary, a jam which has conventionally occurred owing to the defective separation of the body to be transferred between the paper guide and the transfer belt can be eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic printer,
More particularly, it relates to a toner fixing device for an electrophotographic printing device.

[0002]

2. Description of the Related Art FIG. 2 is a diagram showing the overall construction of an electrophotographic printing apparatus equipped with a conventional toner fixing device.

In FIG. 2, the photoconductor 1 is irradiated with light 2 such as a laser beam to form an electrostatic latent image on the photoconductor 1. The electrostatic latent image is developed by the developing device 3. Transferee 5
Is fed from the feeding device 4 to the endless toner transfer belt 7 via the pick roller 6, and is conveyed while being pressed by the photoconductor 1.

At this time, corona discharge is applied to the pressing portion by the charger 8 and the toner image 10 formed on the photosensitive member 1 is transferred to the transfer target member 5.

The transfer belt 7 includes a belt holding roller 9-1.
9 to 9-3, the transfer target body 5 is kept at an appropriate tension, and after passing over the paper guide 11, the toner fixing roller 12 and the pressing roller 13 having the heater lamp 19 built therein.
The toner image 10 is fed into the space and is heated and pressed in the area.
Is fixed on the transfer target 5.

When the transferred body 5 is sent from the transfer belt 7 to the paper guide 11, corona discharge is generated by the peeling corotron 18 so that the transferred body 5 is not wound around the transfer belt 7, and the transferred body 5 is peeled off. To do. Further, in order to prevent the transferred body 5 from being wound around the fixing roller 12, a separation claw 17 is provided in the vicinity of the fixing roller 12.

The transferred body 5 separated by the separating claw 17
Is sent into the stacker 15 via the paper guide 14, and the series of printing operations is completed in this manner.

The surface of the transfer belt 7 is cleaned by a cleaner 16 such as a brush.

[0009]

The overall construction of the electrophotographic printing apparatus provided with the conventional toner fixing device is as described above, but in the conventional case, the transfer belt 7 and the fixing device (fixing roller 12, Since the pressing roller 13, the paper guide 11, the separating claw 17, etc.) are separately configured, there is a drawback that the printing apparatus becomes large.

Further, although the peeling corotron 18 is used, there is a situation in which a jam occurs between the paper guide 11 and the transfer belt 7 due to defective peeling.

An object of the present invention is to reduce the size of the apparatus as compared with the conventional one, and moreover, there is a jam of the transferred body, which has occurred conventionally.
That is, the occurrence of a jam caused by a defective separation of the transferred material between the paper guide 11 and the transfer belt 7 shown in FIG. 2 is eliminated.
An object is to provide an improved electrophotographic printing device.

[0012]

Means for Solving the Problems The above-mentioned object is to press a transfer target, which is electrostatically attracted to a transfer belt and is conveyed, to a photosensitive member,
After the electrostatic attraction toner image carried on the surface of the photoconductor is transferred to the transfer target, the transfer target is fixed to the fixing roller and the pressing roller.
In the electrophotographic printing apparatus for feeding and fixing the toner image on the transfer medium by fixing the toner image on the transfer body, the pressing roller is located on the downstream side in the rotation direction of the transfer belt and faces the fixing roller. -Achieved by holding the transfer belt around the roll.

[0013]

According to the present invention having the above-described structure, the transfer belt is directly mounted on the pressing roller which is located on the downstream side in the rotational direction of the transfer belt which feeds the transferred material, and which is opposed to the fixing roller. Since the roll is held, the transfer target placed on the transfer belt, that is, the transfer target to which the toner image has been transferred is directly pressed against the fixing roller on the downstream side in the rotation direction of the transfer belt. It is sent to the roller.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is an overall structural explanatory view showing a specific example of an electrophotographic printing apparatus provided with a toner fixing device according to the present invention.

In FIG. 1, a heat-resistant transfer belt 7 made of, for example, polyimide (manufactured by Hokushin Kogyo Co., Ltd.) has two belt holding rollers (9) arranged in parallel to each other in the axial direction.
-1, 9-3) and the pressing roller 13 made of silicon rubber are rotated with appropriate tension applied. The fixing roller 12 is arranged at a position adjacent to the pressing roller 13. In this embodiment, the fixing roller 12 is
The core metal made of aluminum is coated with fluororesin.

In the above construction, when the photosensitive body 1 made of amorphous silicon is irradiated with the light 2 such as a laser beam, an electrostatic latent image is formed, and the electrostatic latent image is developed by the developing machine 3. The developed toner image 10 is transferred onto the transfer-receiving member 5 fed from the feeding device 4 to the transfer belt 7 to the charger 8
Electrically transferred by.

The transferred body 5 on which the toner image 10 is transferred is
By the transfer belt 7, the fixing roller 12 and the pressing roller 13
In between.

The fixing roller 12 is pressed against the pressing roller 13 with an appropriate pressure by a pressing mechanism (not shown), and is controlled to a predetermined temperature by a control mechanism (not shown).

The transferred material 5 fed between the fixing roller 12 and the pressing roller 13 has a toner image 1 due to heat and pressure.
After fixing 0, the separating roller 17 fixes the fixing roller 12
The sheet is peeled from the sheet and conveyed into the stacker 15.

On the other hand, the offset toner adhered to the transfer belt 7 at the time of fixing is removed by the cleaner 16.

The transfer belt 7 is preferably coated with a fluororesin on at least its surface, preferably both the front and back surfaces, in order to prevent toner contamination as much as possible.

In this embodiment, the polyimide film is used as the heat resistant transfer belt material. However, the same as the above embodiment even if another heat resistant material such as silicone rubber is used as the transfer belt material. The effect of can be obtained.

[0023]

The present invention is as described above, and according to the present invention, it is located at the downstream side in the rotational direction of the transfer belt 7 that feeds the transferred material 5, and is pressed against the fixing roller 12. Low
Since the transfer belt 7 is directly wound around the roller 13, in other words, the transfer belt 7 and the pressing roller 1 of the fixing device are pressed.
By integrating 3 and 3, the transfer target 5 placed on the transfer belt 7, that is, the transfer target 5 to which the toner image 10 has been transferred is provided on the downstream side in the rotation direction of the transfer belt 7. The belt is directly fed between the fixing roller 12 and the pressing roller 13, and the belt holding roller 9-2 of FIG. 2 conventionally provided in this portion, and further the paper guide 14 and the like. , The size of the electrophotographic printing apparatus is reduced, and at the same time, by omitting the paper guide 14, a jam of the transferred body 5, which has occurred conventionally, that is, the paper shown in FIG.
It is possible to prevent the occurrence of a jam between the guide 11 and the transfer belt 7 due to a defective separation of the transferred material.

[Brief description of drawings]

FIG. 1 is an overall configuration explanatory view showing a specific example of an electrophotographic printing apparatus including a toner fixing device according to the present invention.

FIG. 2 is a diagram illustrating the overall configuration of an electrophotographic printing apparatus including a conventional toner fixing device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Photosensitive member, 3 ... Developing device, 5 ... Transferred object, 7 ... Toner transfer belt, 8 ... Charging device, 9 ... Belt holding roller, 10 ...
Toner image, 12 ... Toner fixing roller, 13 ... Pressing roller.

Claims (2)

[Claims] 1. An endless toner transfer belt supported by a belt holding roller, a photoconductor disposed adjacent to the transfer belt, and a transfer belt sandwiched with respect to the photoconductor. A charging device for charging the transfer belt, which is disposed at a position facing each other, and a toner located downstream of the transfer belt in the rotation direction.
A fixing roller, and a pressing roller disposed adjacent to the fixing roller, and presses the transferred body that is electrostatically adsorbed on the transfer belt and conveyed to the photoconductor, After the electrostatic attraction toner image carried on the surface of the photoconductor is transferred to the transfer target, the transfer target is fed between the fixing roller and the pressing roller, and the toner on the transfer target is transferred. In an electrophotographic printing apparatus that heats and pressurizes an image to fix the image, the fixing roller is located on the downstream side in the rotation direction of the transfer belt.
A transfer belt is wound around and held by a pressing roller facing the roller, and the toner image on the transfer medium is fixed by the pressing roller and the fixing roller having the above-mentioned structure. Toner fixing device for printing device. 2. The toner fixing device for an electrophotographic printing device according to claim 1, wherein at least the front surface of both surfaces of the toner transfer belt is coated with a fluororesin.