JPH0553269B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic recording apparatus, and particularly to an apparatus that is suitable for reducing the size and weight of the apparatus.

In an electrophotographic apparatus, when recording an image on plain paper, a photoconductive drum or belt or a dielectric recording drum or belt is used as the recording medium, and after a toner image is once formed on this, the plain paper (recording body)
Transfer to. Such devices have the disadvantage that the entire device is large and heavy, particularly due to the structure of the recording paper conveying means and the size of the recording drum or belt, which has hindered the widespread use of the recording device and its economy.

FIG. 1 is a block diagram of a typical conventional laser beam printer. As the photoconductive drum 1 rotates, it is charged by a charger 2. Next, the drum is scanned with a laser beam modulated with a recording signal to create a charge latent image. Scanning of the laser beam can be performed, for example, by using a beam from a semiconductor laser 4 using an optical system comprising a rotating mirror 5 and a scanning convergence lens 6.

The charge latent image formed by the laser beam irradiation is developed by a developing device 7 to form a toner image on the drum.
The toner image is transferred from the drum to the recording paper in the presence of a corona charge from the transfer charger 9 when the recording paper stored in the cassette is fed out and brought into contact with the drum. The recording device onto which the toner image has been transferred is transported by a transport roller 10 to a fixing roller 11, where it is finally fixed.

After the toner on the photoconductive drum 1 is transferred to the recording paper, the toner remaining on the drum is removed by a cleaner 12, and the drum is used for the next image formation.

In such conventional methods and configurations, storage of recording paper,
Due to the size and positioning of the parts to be transported and arranged around the drum, there is a drawback of increasing the size, and the diameter of the drum used had to be around 100 mmφ.

The first object of the present invention is to eliminate such conventional drawbacks and provide a recording apparatus that can be made smaller and lighter in weight.The second object of the present invention is to provide a recording apparatus that can be easily separated from the photoconductive drum. It's about doing.

In order to achieve the above object, the electrophotographic recording device of the present invention first uses a small diameter drum of 80 mm or less in diameter as the photoelectronic drum, with the aim of making the device smaller and lighter. In order to shorten the paper transport path from paper to paper output and reduce the number of required parts, the paper transport path was placed above the photoconductive drum so that the fixing means after paper processing was completed could also be used as the transport means. They were arranged in a substantially straight line. That is, the toner image formed on the surface of the photoconductive drum is transferred onto the upper side of the photoconductive drum so as to be in contact with the lower surface of the fed recording paper and the lower surface of the fed recording paper. A conveying/fixing means that transports and fixes the toner image while carrying it on the lower surface, and a paper ejecting means that sequentially stacks the fixed recording paper on a substantially straight line that transports the recording paper from the paper feeding means to the paper ejecting means. placed above. Furthermore, the recording paper is transferred above the photoconductive drum, and the diameter of the photoconductive drum is made small to 80 mm or less, thereby making it easy to separate the recording paper from the drum.

Further, the electrostatic latent image forming means and the residual toner removing means are arranged below the periphery of the photoconductive drum.

FIG. 2 shows one embodiment of the invention.

The photoconductive drum 1 is uniformly charged with a charger 2, and then optically scanned with a laser beam 3 to form a charge latent image. The formed charge latent image is developed by a developing device 7 to form a colored toner image on the photoconductive drum 1. Next, one sheet of the recording paper 8 stacked in the paper feed paper storage means 26 is carried out by the paper feed rollers 18, 19 and 21, 22, and a corona charger 9 for transfer is carried out.
The toner image is transferred by. The transferred recording paper 8 is separated from the photoconductive drum and moved to fixing rollers 23 and 24 which also serve as conveyance rollers. The shorter the distance between the fixing rollers 23, 24 and the separation point of the recording paper on the photoconductive drum, the better. For this reason as well, it is preferable that the diameter of the photoconductive drum be 40 mm to 80 mm. The paper feed rollers 18 and 19 carry the stacked recording paper 8.
The roller 18 is rotated in the opposite direction to the roller 19, and the paper feed rollers 21 and 22 are rotated in the same direction so that the sheets can be sequentially pulled out from below. Also, instead of the corona charger 9 for transfer,
A bias may be applied to a transfer roller. In this case, the transfer roller also functions as a recording paper transport roller. At this time, the transport rollers 21 and 2 are separated from the transfer roller and the photoconductive drum 1.
2, and the conveyance rollers 21 and 22 can be omitted. The fixing rollers 23 and 24 fix the image using heat or pressure. In the case of thermal fixing, one of the fixing rollers 23 and 24 becomes a heat roll.

In this way, the recording paper 8 is conveyed to the exit while being fixed. The recorded sheets are sequentially stacked in the recording order. In other words, pages can be aligned.

After the transfer process is completed, the toner remaining on the surface of the photoconductive drum 1 is scraped off by a cleaning blade 13.

In the above description, a laser beam is used as a means for forming an electrostatic latent image on the photoconductive drum 1, but instead of the laser beam, a recording element in which light emitting elements (LEDs) are arranged or a light shutter array may be used. Furthermore, a dielectric material may be used as the recording body instead of the photoconductive drum, and a pin electrode array may be used as the recording element.

With the configuration of the present invention as described above, in an apparatus where the circumferential speed of the photoconductive drum is approximately 150 mm/s or less, the diameter of the photoconductive drum can be reduced to approximately 40 to 80 mm, and the overall size of the apparatus can be reduced to less than half of the conventional size. It is also possible to do so.

Further, in this embodiment, a separation belt 25 shown by a broken line may be provided, and after the toner image is transferred onto the recording paper 8 by a corona charger 9, it may be transported by the separation belt 25 and the fixing rolls 23 and 24. . It should be noted that the separation belt does not need to be one that wraps around a drum and a fixing roll as shown in FIG. 2, but may be something like a guide piece.

In FIG. 2, the portion for storing the paper before recording is only the support 26 on the plate, and there is no need to make it box-shaped as in the conventional case, and it is sufficient to place an appropriate amount of paper thereon. Further, in order to reduce the influence of moisture absorbed by the recording paper, a plate-like small-capacity heating element may be provided on the support 26.

FIG. 3 shows another embodiment according to the invention.

In this embodiment, a corona charger 9 for transfer, fixing rolls 23 and 24, and a conveyance roll 2 shown in FIG.
In place of rollers 1 and 22, a roller 14 is provided which also serves for transfer, fixing, and conveyance. Therefore, by adopting this structure, the number of parts can be reduced compared to the case shown in FIG. 2, and if the diameter of the photoconductive drum is made the same as that shown in FIG. 2, it is possible to further reduce the size. In this embodiment, since the roll 14 is used for both transfer, fixing, and conveyance, if thermal fixing is to be performed, the roll 14 must have a built-in heating element such as a heater, and the photoconductive drum used at this time must be installed. 1
In this method, a heat-resistant inorganic or organic photoconductor such as amorphous silicon, CDS, polyvinyl carbazole sensitized photoreceptor, etc. is used. When performing pressure fixing, a photoreceptor made of amorphous silicon or CDE, which has strong mechanical strength, is sintered into a ceramic shape.

It is an effective means to apply a bias voltage to the roll 14 in order to facilitate the transfer of toner.

In this way, the recording paper 8 is conveyed to the exit while toner is transferred and fixed. Toner, paper powder, etc. adhering to the roll 14 are wiped off by a cleaning pad 15. Further, toner remaining on the photoconductive drum 1 is scraped off by a toner cleaning blade 13.

As described above, this embodiment has the advantage that the number of component parts can be reduced compared to the embodiment shown in FIG. 2, and the device can be further miniaturized.

FIG. 4 shows another embodiment according to the present invention.

In this embodiment, the toner image formed on the photoconductive drum 1 is transferred to the transfer roll 16, and then further transferred to the recording paper 8 and fixed thereon. A bias power supply 20 is connected to the transfer roll,
It is preferable to apply a transfer voltage, but it can be omitted if the transfer roll 15 utilizes adhesiveness and transfers the toner through adhesiveness. The fixing roll 17 is a heat or pressure roll, which also serves to transport the recording paper and also serves as a driving roll for another transport roll 18.

In FIG. 4, transfer roll 16 may also be a fuser roll and may be a heat or pressure roll. It is also effective to apply a bias voltage between the rollers 16 and 17 to facilitate the transfer of toner to the recording paper.

When the fixing roll in FIGS. 3 and 4 is a heated roll, it is preferable to use means for cooling the drum, such as by passing air through the inner cavity of the drum.

FIG. 5 shows another embodiment of the invention. Recording paper 8
are fed out one by one from the bottom by transport rolls 18 and 19, and are connected to the drum 1 by applying a bias (not shown).
The toner image is transferred onto the recording paper 8 between the transfer rollers 33 . The drum 1 and the transfer roller 33 also serve as paper feeding rollers. Subsequently, the recording paper 8 is peeled off from the drum by a separation belt provided between the fixing roller 23 and the drum 1 or a separating piece in place of the separation belt, and is fixed by heat or pressure by the fixing rollers 23 and 24. The fixing roller also functions as a paper feeding roller, and ejects the recording paper on which recording and fixation have been completed onto the tray 28. In this case, the recording surface is on the lower side and the recording state cannot be seen immediately. Therefore, if you want to check the recording status immediately, you can make the guide plates 29 face each other and push the rollers 30 and 31 through 32 onto the tray 27, so that the printed surface will be on the top and you can quickly check the recording status. Become. This kind of structure is convenient when recording is not continuous or when in test mode.

As described above, by configuring a recording apparatus by reducing the diameter of the recording drum as in the present invention, it is possible to realize a small and lightweight electrophotographic recording apparatus.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional recording apparatus, and FIGS. 2 to 5 are block diagrams of a recording apparatus according to the present invention. 1... Recording drum, 7... Developing device, 14... Transfer/fixing/conveyance roller, 18, 19... Conveyance roller, 26... Recording paper support plate.

Claims (1)

[Scope of Claims] 1. An endless photoconductor, charging means for charging the surface of the photoconductor, and latent image formation for forming a charge latent image on the surface of the photoconductor charged by the charging means. a developing means for developing the formed charge latent image with a colored toner to form a toner image on the surface of the photoconductor; and a developing means for transferring the developed toner image to a recording paper and transferring the developed toner image to the photoconductor after the transfer. an electrophotographic recording device for fixing the toner image transferred to recording paper, the electrophotographic recording device comprising a residual toner removing means for removing toner remaining on the surface of the recording paper, using a photoconductive drum having a diameter of 80 mm or less as the photoconductor; The latent image forming means is provided below the periphery of the photoconductive drum, and the charging means and the residual toner removing means are arranged in the rotational upstream direction of the photoconductive drum and in the rotational downstream direction with respect to the latent image forming means. The developing means are respectively disposed, and above the periphery of the photoconductive drum, there is provided a paper feeding means for sequentially feeding out the recording paper, and a sheet is formed on the surface of the photoconductive drum so as to be in contact with the lower surface of the fed out recording paper. A conveying/fixing means for transporting and fixing the transferred toner image while carrying it on the lower surface, and a paper ejecting means for sequentially stacking the fixed recording paper are provided diagonally above the recording paper. The paper feeding means is arranged substantially in a straight line so as to feed the paper to the discharging means provided diagonally downward, and the paper feeding means is arranged in the rotational upstream direction with respect to the transfer means, and the paper feeding means is arranged in the rotational downstream direction with respect to the transfer means. An electrophotographic recording device characterized in that paper ejection means are respectively arranged. 2. In the electrophotographic recording apparatus according to claim 1, the paper discharge means is a recording paper surface selection means for selecting and feeding out the toner bearing surface of the recording paper after fixing so as to face either upward or downward. An electrophotographic recording device comprising: