JPH06295133A - Image forming device - Google Patents

Abstract

PURPOSE:To make the structure of the carrying path of a recording paper simple, light in weight and inexpensive by carrying the recording paper at least in a section to a fixing device from a photosensitive body by an image carrying belt. CONSTITUTION:A supporting roller 15 whose diameter is almost identical to a photosensitive drum 1 is freely rotatably provided at a position, separated to some extent from the drum 1 in the direction of a paper ejecting side. Then, the image carrying belt 2 is wound between the roller 15 and the drum 1. The belt 2 is passed through space between the drum 1 and a developing unit 5 at the same speed as the circumferential speed of the drum 1 so as to be moved while carrying an image formed on the drum 1 by developer. Then, the belt 2 travels by facing the developer attaching surface thereof upward in the section that it is advanced to the roller 15 side from the drum 1 side (going section). On the other hand, it travels by facing the developer attaching surface downward in the section that it is advanced to the drum 1 side from the roller 15 side (returning section).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a copying machine, a printer,
Also, the present invention relates to an image forming apparatus using an electrophotographic method used for a facsimile machine or the like.

[0002]

2. Description of the Related Art In a machine of an image forming apparatus, a recording paper pulled out from a paper cassette or the like is conveyed to a position near a photosensitive drum, and is transferred to the photosensitive drum in synchronization with the rotation of the photosensitive drum. A recording paper conveyance path is provided between the charger and the recording paper for guiding the recording paper having been transferred to the fixing unit and discharging the recording paper passing through the fixing unit to the outside of the machine.

[0003]

However, the above-mentioned recording paper conveying path has many parts such as a paper guide, a driving roller for conveying the recording paper, bearings such as the driving roller, and driving gears of the driving roller. Since it is required, it hinders downsizing and weight reduction of the image forming apparatus, and also causes an increase in cost. In particular, in the paper feeding method by front loading, which has been widely used in recent years, the configuration becomes complicated, the shape of parts becomes complicated, the number of parts increases, the driving structure becomes complicated, etc. It has become noticeable. Further, the cost of manufacturing the mold is high due to the complicated shape of the parts, and it is difficult to assemble at the production stage.

In view of the above circumstances, it is an object of the present invention to provide an image forming apparatus in which the structure of the recording paper conveyance path is simplified.

[0005]

In order to solve the above-mentioned problems, an image forming apparatus of the present invention is wound around a support roller and a photoconductor and has the same speed as the peripheral speed of the photoconductor. And a developing device, and an image carrier belt for carrying and moving an image of the developer to be formed on the photoconductor by passing between the photoconductor and the developing device, and at least from the photoconductor to the fixing device by the image carrier belt. It is characterized in that the recording paper conveyance path of the section is formed.

[0006]

According to the above construction, by mounting the recording paper on the image bearing belt at the position where the image formed by the developer is formed, it becomes possible to transfer the image formed by the developer onto the recording paper, and In this state, the recording sheet moves on the belt or pulled by the belt, and in this state, the image is fixed on the recording sheet by passing through the fixing section. That is, since the recording paper is conveyed by the image bearing belt at least in the section from the photoconductor to the fixing device, the driving mechanism for conveying the recording paper is not necessary in this section, and the structure of the recording paper conveyance path is reduced. Simplification, weight reduction, and cost reduction, and easy assembly at the time of manufacturing.

[0007]

【Example】

(Embodiment 1) The present invention will be described below with reference to the drawings showing the embodiment.

FIG. 1 is a system configuration diagram showing a schematic configuration of an image forming apparatus of the present invention configured as a printer. In the figure, reference numeral 1 denotes a photosensitive drum, around which a charging unit 3 for applying an electric charge to the surface of the drum 1 and an exposure for irradiating a laser beam to form an electrostatic latent image on the surface of the drum 1 according to an image signal. A unit 4, a developing unit 5 for adhering a developer to the above electrostatic latent image, a discharge lamp 8 for removing residual charges on the surface of the photosensitive drum 1, and the like are provided.

A support roller 15 having a diameter substantially the same as that of the photosensitive drum 1 is rotatably provided at a position separated from the photosensitive drum 1 in the sheet discharge side direction. An image bearing belt 2 is wound around the support roller 15 and the photoconductor drum 1, and the image bearing belt 2 is mounted on the photoconductor drum 1.
And the developing unit 5 are passed at the same speed as the peripheral speed of the photosensitive drum 1, and carry and carry an image of the developer to be formed on the photosensitive drum 1. There is. The image carrying belt 2 carries an image of the developer to be formed on the photosensitive drum 1 as described above, and, as will be described later, when it passes through the fixing device 6, Since it is given heat, it is formed of a thin (preferably 150 μm or less) seamless film having insulation, semiconductivity, and heat resistance.

The photosensitive drum 1 rotates clockwise in the figure,
The image bearing belt 2 rotates clockwise in the drawing using the drum 1 as a driving roller. Therefore, the image carrier belt 2
Travels with the developer adhering surface facing upward in a section from the side of the photoconductor drum 1 to the side of the support roller 15 (hereinafter referred to as a forward section), while traveling from the side of the support roller 15 to the side of the photoconductor drum 1. In the section to be advanced (hereinafter referred to as the return section), the developer-adhesion surface is directed downward. If the traveling speed of the image bearing belt 2 is too fast, unstable static electricity will be accumulated between the surface of the image bearing belt 2 and the recording paper, so that means for removing the static electricity is required.
In order to eliminate such means, the image carrier belt 2
It is desirable that the traveling speed of 40 mm / sec or less.

A fixing device 6 for fixing the image formed by the developer formed on the belt 2 to the recording paper is provided in the outward path of the image carrying belt 2. The fixing device 6 is provided on a guide plate 6b provided on the developer adhering surface side (upper surface side) of the image carrying belt 2 and on a lower surface side of the image carrying belt 2 with a slight distance from the guide plate 6b. The heater 6a is provided. On the other hand, a belt cleaner 9 is provided in the return path section of the image bearing belt 2, and the developer adhering surface is cleaned by the movement of the image bearing belt 2 itself.

Further, above the developing unit 5, a paper feeding / conveying path and a resist roller (neither is shown).
The recording paper conveyed through the paper feed conveying path is mounted at the image forming position on the image carrying belt 2 by the registration roller at a good timing. The upper part of the outer frame of the developing unit 5 itself may form the paper guide of the paper feed / conveyance path.

Next, the operation of the image forming apparatus constructed as above will be described.

An electrostatic latent image is formed on the surface of the photosensitive drum 1 by its rotation and laser irradiation by the exposure unit 4. When this electrostatic latent image comes to a position facing the developing unit 5, The developer is attracted according to the electrostatic latent image. At this time, between the developing unit 5 and the photosensitive drum 1, an image bearing belt 2 that rotates in synchronization with the drum 1 is provided.
, The developer is attached to the image bearing belt 2 to form an image, and the image formed by the developer moves with the movement of the belt 2.

On the other hand, the recording sheet conveyed from the sheet feeding conveying path (not shown) is mounted on the image forming position on the image carrying belt 2 by the registration roller (not shown) at a proper timing, so that an image is recorded by the developer. The recording sheet can be transferred and fixed on the sheet, and in this state, the recording sheet rides on the image bearing belt 2 and passes through the fixing device 6. When passing through the fixing device 6, heat is applied from the heater 6a, the developer is melted by the heat, and the melted developer soaks into the recording paper on the belt 2 and hardens. By the (so-called anchor effect), the image is transferred and fixed on the recording paper.

When the forward section of the image carrier belt 2 is completed, the recording paper is discharged to the outside of the machine through a paper discharge path (not shown). On the other hand, the image carrying belt 2 changes its traveling direction by 180 ° and advances in the return path section, and the belt cleaner 9 removes the residual potential, residual developer, paper dust and the like adhering to the belt 2. Be seen.

As described above, since the recording paper is carried on the image carrying belt 2 in the forward path, it is conveyed.
It is possible to eliminate the need for the recording paper conveyance path in this forward path section. Therefore, the recording paper transporting roller and its bearings for constituting this are not required, and the structure of the recording paper transporting path can be simplified, the weight and cost can be reduced, and the assembly at the time of manufacturing can be facilitated. .

Further, since the recording paper is carried on the image bearing belt 2, the back surface (the surface not in contact with the developer) of the recording paper is almost completely prevented from being soiled. Further, by providing the belt cleaning device 9, it is possible to eliminate the need for regular maintenance such as paper dust removal and cleaning of falling toner, which has been required in the conventional recording conveyance path.

(Embodiment 2) Another embodiment of the present invention will be described below with reference to FIG.

In the image forming apparatus of this embodiment, instead of the supporting roller 15 of the first embodiment, two supporting rollers 1 of small diameter are used.
1a and 11b are provided. Of these, the support roller 11a forming the forward path section of the image carrying belt 2
Is made of a heat-resistant material and functions as a fixing press roller, and the fixing device 6 is constituted by the heat roller 10 which is opposed to the image bearing belt 2 in between.
Incidentally, reference numeral 12 is a separation claw for separating the recording paper from the image carrying belt 2.

(Embodiment 3) The image forming apparatus of this embodiment is
In the image forming apparatus of the first embodiment, the developing unit 5 is arranged laterally of the photoconductor drum 1, but is arranged below the photoconductor drum 1 as shown in FIG. As a result, the lateral direction of the image forming apparatus can be made compact.

(Embodiment 4) The image forming apparatus of this embodiment is
As shown in FIG. 4, the image forming apparatus according to the third exemplary embodiment is arranged vertically. In this case, the recording paper is supported by electrostatic force or a roller (not shown), etc.
It will be moved by being pulled by. Further, in this case, since the recording paper is conveyed in the range shown by the arrow in the figure, the range that can be used as the recording paper conveyance path in the image carrying belt 2 is wide.

In the above embodiments, the photoconductor drum is shown as the photoconductor, but the present invention is not limited to this and can be applied to the case where a photoconductor belt is used. Further, although the configuration in which the transfer charger is omitted is shown, it goes without saying that the present invention can be applied to an image forming apparatus having a configuration using this transfer charger.

[0024]

As described above, according to the present invention, the recording paper is conveyed by the image carrying belt at least in the section from the photoconductor to the fixing device. A mechanism is not required, the structure of the recording paper conveyance path can be simplified, the weight can be reduced, and the cost can be reduced, and the assembly at the time of manufacturing can be facilitated.

[Brief description of drawings]

FIG. 1 is a system configuration diagram showing an outline of an image forming apparatus of the present invention.

FIG. 2 is a system configuration diagram showing an outline of an image forming apparatus according to another embodiment of the present invention.

FIG. 3 is a system configuration diagram illustrating an outline of an image forming apparatus according to another embodiment of the present invention.

FIG. 4 is a system configuration diagram showing an outline of an image forming apparatus according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor drum 2 Image carrying belt 5 Developing unit 9 Belt cleaning device 11a Support roller 11b Support roller 15 Support roller

Claims (1)

[Claims] 1. A development to be formed on the photoconductor by being wound around a support roller and the photoconductor and passing between the photoconductor and a developing device at the same speed as the peripheral speed of the photoconductor. An image forming apparatus, comprising: an image carrier belt that carries and moves an image of an agent, and the image carrier belt forms a recording paper conveyance path at least in a section from a photoconductor to a fixing device.