JPH09222761A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate parts such as a driving belt, a belt driving gear pulley and so on, by making sheet transporting means possible to serve as the driving means for driving a fixing part and a paper discharging roller. SOLUTION: In this image forming device capable of forming an image by an electrophotgraphic system, the transporting means for transporting a paper sheet is constituted, by adopting a toothed belt provided with teeth on an inside periphery as the transporting belt 9a, making the transporting roller 72a having the teeth on its outer periphery engaged with the toothed belt or the like, and letting the transporting means serve as driving force transmitting means for transmitting the driving force of the driving means 6.

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 adopting an electrophotographic system, and mainly to an image forming apparatus having an improved structure of a sheet material conveying section.

[0002]

2. Description of the Related Art In a conventional image forming apparatus, a photosensitive drum 2 shown in FIG. 2 is exposed by a scanner (not shown) to form a latent image, and the latent image is visualized by developing means. A toner image is formed. As shown in FIG. 2, a conveyor belt 9b is wound around a pair of conveyor rollers 73 and 74 in the conveying device for conveying the sheet material from the transfer portion to the fixing portion, and the driving force of the main motor 6 is The transfer unit 4 that transfers the toner image on the drum 2 onto the recording material P is driven, and is transmitted to the gear pulley 12 via the drive belt 10, and is conveyed by the gear train 8 to the conveying device 1 and the fixing roller 51.
Also, the fixing unit 5 including the pressure roller 52 and a paper discharge roller (not shown) are driven.

[0003]

However, when there is a drive belt as in the above-mentioned conventional example, the apparatus becomes large in size because it requires a space for the belt and a drive gear pulley for driving the belt, and the like. Further, since the structure becomes complicated, there is a drawback that the cost also rises.

The present invention has been made in view of the above circumstances. An image forming which has a simple structure and saves space can be realized by using a conveyor belt as a driving belt for driving a fixing device and the like. The purpose is to provide a device.

[0005]

In order to achieve the above-mentioned object, a first invention according to the present application is an image forming apparatus adopting an electrophotographic system, wherein a conveying means for conveying a sheet is
It is characterized in that it also serves as a driving force transmitting means for transmitting the driving force of the driving means.

In a second aspect of the present invention, the conveying means forms an image on a sheet, an image forming means, a feeding means for feeding the sheet, or a driving means for driving both the image forming means and the feeding means. The driving force transmitting means for transmitting the driving force is also used, and the image forming means or the feeding means or both the image forming means and the feeding means are driven by the driving force.

In a third invention according to the present application, the conveying means also serves as a drive transmitting means for transmitting a driving force of a fixing means or a paper discharging means or a driving means for driving both the fixing means and the paper discharging means, The driving unit drives the fixing unit or the sheet discharging unit or both the fixing unit and the sheet discharging unit.

In a fourth aspect of the present invention, the conveying means is composed of a toothed belt having teeth on its inner circumference and a toothed roller having teeth engaging with the teeth of the belt. It is characterized by

A fifth aspect of the present invention is characterized in that the conveying means is composed of a roller having at least an outer peripheral portion formed of a high friction member and a belt engaging with the roller.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) FIG. 1 is a block diagram showing an embodiment of a carrying device of the present invention.

In FIG. 1, the paper P fed from a paper feed cassette (not shown) is fed in the direction of the arrow by a registration roller (not shown), and the toner image on the photosensitive drum 2 is transferred when the paper P passes. The image is transferred onto the sheet P by the unit 3. Next, the paper P is conveyed toward the fixing unit 5 by the conveyance unit 1 in order to fix the image transferred on the paper P.

The transport unit 1 includes a pair of transport rollers 71.
a, 72a, a conveyor belt 9a, and the like. The rotation of the output gear 6a of the drive motor 6 is transmitted to the conveyance roller gear 71b, whereby the conveyance roller shaft 7a rotates and the conveyance roller 71a rotates. Transport roller 71
Teeth are provided on the roller peripheral surfaces of a and 72a and the inner circumference of the conveyor belt 9a, the drive of the conveyor roller 71a is transmitted to the conveyor roller 72a via the conveyor belt 9a, and the conveyor roller shaft 7b rotates. Thereby, the transport roller gear 72b
Rotates, the driving force is transmitted to the fixing driving gear 5a via the gear train 8 having the gears 81 and 82, and the fixing roller 51 is driven. Further, the driving force of the transport roller gear 72b is transmitted to a sheet discharge roller (not shown) for discharging the sheet P that has completed the fixing process.

According to the above-described embodiment, the conveyor belt also serves as a transmission means for transmitting the driving force of the motor to the fixing roller and the paper discharge roller, so that the space can be saved.
Since the number of parts is small, it is possible to provide a transportation device with a reduced cost.

In another embodiment, a high friction member is used for the conveying roller, so that a flat surface without teeth is used on the surface of the conveying roller and the inner circumference of the conveying belt. You may make it double.

Further, the driving force of the motor for driving the fixing section and the sheet discharge roller is transmitted to the transfer section, the photosensitive drum, the resist roller, the sheet feed roller and the like via the conveyor belt so as to drive them. Good.

[0016]

As described above, according to the present invention,
Since the sheet material conveying means also serves as the driving means for driving the fixing portion and the paper discharge roller, parts such as the drive belt and the belt driving gear pulley can be omitted, and the number of parts can be reduced. Since the cost is reduced and the proportion of the drive system inside the main body is small, the main body can be downsized.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of an image forming apparatus according to the present invention.

FIG. 2 is a configuration diagram of a conventional image forming apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Conveying device 2 ... Photosensitive drum 3 ... Transfer roller 4 ... Image transfer part 5 ... Fixing part 6 ... Main motors 7a, 7b ... Conveyor roller shafts 71a, 72a, 73a, 74a ... Conveyor roller shafts 71b, 72b, 73b, 74b ... conveyance roller gear 8 ... driving gear train 9a, 9b ... conveying belt 10 ... driving belt 11,12 ... pulley gear

Claims (5)

[Claims] 1. An image forming apparatus adopting an electrophotographic system, wherein a conveying means for conveying a sheet also serves as a driving force transmitting means for transmitting a driving force of a driving means. 2. The conveying means also functions as an image forming means for forming an image on a sheet and / or a driving force transmitting means for transmitting a driving force of a driving means for driving a feeding means for feeding a sheet, The image forming apparatus according to claim 1, wherein the image forming unit and / or the feeding unit is driven by a driving force. 3. The conveying means also serves as a drive transmitting means for transmitting a driving force of a driving means for driving the fixing means and / or the sheet discharging means, and the driving means causes the fixing means and / or the fixing means.
Alternatively, the image of the discharging means is driven.
The image forming apparatus as described in the above. 4. The conveying means comprises a toothed belt having teeth on its inner circumference and a toothed roller having teeth engaging with the teeth of the belt. 4. The image forming apparatus according to any one of 3 to 3. 5. The conveying means is constituted by a roller having at least an outer peripheral portion formed of a high friction member, and a belt engaging with the roller.
The image forming apparatus according to any one of 1.