JPH0584906B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic printer, and particularly to an improvement in a transfer paper transport system for transporting paper from a transfer device to a fixing device.

[Conventional technology]

For conventional electrophotographic printers, generally
In order to handle the paper jam during printing, a so-called clam shell structure is adopted, and specifically, it has a registration roller support bearing, a photoreceptor support bearing,
The fixing device support bearing and the like are arranged separately on the upper and lower side plates.

Further, a toner image is transferred to the lower side of a transfer sheet, and the transfer sheet is conveyed to a fixing device in this position.

[Problem that the invention seeks to solve]

However, according to the former method, when replacing consumables such as photoreceptors, it is necessary to open the clamshell and replace the consumables from the side of the printer body. The printer requires a large space to install the printer, as consumables can be pulled out and removed from the side of the printer body.

On the other hand, in the latter case, when the lower side of the transfer paper is guided by a guide member, there is a problem that the unfixed toner image is rubbed.

The present invention transfers a toner image to the lower side of transfer paper,
When conveying the transfer paper to the fixing device in this position, it is possible to eliminate the unfixed toner image from being rubbed and to keep the area required for installing the printer to a small space. Even if a paper jam occurs, it can be easily disposed of, and the fan used to prevent image scratching can also be used instead of using a dedicated fan for cooling the power supply unit and control board, which are heat sources. The power supply unit and control board are forcedly cooled, which not only makes the equipment lighter and more compact, but also has excellent economic efficiency.
Furthermore, it is an improved system that can easily diffuse ozone, which has a pungent odor, generated on the charger side, and does not cause discomfort to the printer operator due to the presence of a localized strong pungent odor. The purpose is to provide an electrophotographic printer.

[Means for solving problems]

The purpose is to charge the photoreceptor with a charger and expose it with an exposure source to form a latent image on the photoreceptor into a toner image using a developing device, and to transfer the toner image on the upper part of the photoreceptor onto transfer paper using a transfer device. Then, in an electrophotographic printer that transports the transfer paper with the unfixed toner image attached to it to a fixing device, the toner image on the upper part of the photoconductor is transferred to the lower side of the transfer paper, and the transfer paper with the unfixed toner image attached is transferred to the lower side of the transfer paper. of,
The wind pressure of the air discharged from the upper transfer fan is such that the upper side of the transfer paper, which is the non-toner image side, comes into contact with the upper transfer guide placed between the transfer device and the fixing device and is conveyed to the fixing device side. In addition to pressing the toner image side of the transfer paper by pressing the toner image side of the transfer paper and fixing the unfixed toner image on the transfer paper, which has been conveyed to the fixing device side as described above, onto the transfer paper by the fixing device, Located on the air inflow side of the transfer fan,
An air circulation duct is provided that has an opening that communicates with the power supply unit, the control board, and an opening that communicates with the charger that generates ozone when charged, and the paper feed section of the paper feed tray relative to the printer body is connected to the top surface of the printer body. This is achieved by arranging the toner cartridge so that it can be replaced from the top surface of the printer body, and by attaching the upper transfer guide to the back surface of a front cover that is located on the top surface of the printer body and can be opened and closed. .

[Effect]

In the above configuration, the transfer paper to which the unfixed toner image is attached by the transfer device is pressed against the toner image side of the transfer paper by the wind pressure of the air discharged from the upper transfer fan, and the non-toner image on the transfer paper is pressed. It is conveyed to the fixing device side with its side in contact with the upper transfer guide, which can prevent unfixed toner images from being rubbed, and in electrophotographic printers,
The unfixed toner image attached to the transfer paper is attracted to the transfer paper with a Coulomb force approximately 1000 times the weight of the toner, so the individual toner particles constituting the toner image are attracted to the transfer paper with a Coulomb force approximately 1000 times the weight of the toner. Even if wind pressure is applied from the upper transfer fan against its own weight, the unfixed toner image will not be disturbed.

In addition, according to the present invention, even if a paper jam occurs, the paper jam can be disposed of by simply opening the front cover located on the top of the printer main body, making it extremely easy to maintain the paper feed path. It can be done. Furthermore, according to the present invention, maintenance can be easily performed from the top surface of the printer main body, such as removing and replacing the photoreceptor and replenishing toner. For example, to remove a photoconductor from the printer body, open the front cover, rotate the photoconductor around its center of rotation, and then pull the photoconductor upward. The above operations can be performed in reverse. Toner can also be replenished by replacing the toner cartridge from the top of the printer body. As a result, it is no longer necessary to replace consumables, such as a photoreceptor, from the side of the printer body, unlike conventional printers that employ a clam shell structure. In other words, unlike the conventional printers, the printer does not require a large space to install the printer, as it requires pulling out and removing consumables from the side of the printer body. The area required for this can be reduced to a smaller space than before.

Note that if you feed the transfer paper from the top of the printer instead of from the side, the paper feed tray will not protrude from the side of the printer, and the printer will be able to The area required for installation can be kept to a small space.

By the way, the power supply unit has a heat output of approximately 70W, and the control board that controls the sequence operation of the electrophotographic process and the interface function with the host,
Although it has a heat generation amount of approximately 60W, if the power supply unit and control board are configured to be forcibly cooled by the upper transfer fan, not only the photoreceptor but also the toner contained in the developer unit can be heated to high temperatures. It is possible to prevent thermal deterioration of weak materials as much as possible, and instead of using a dedicated fan to cool the power supply unit and control board, which are heat sources, the fan used to prevent unfixed toner images from rubbing can also be used to cool the power supply unit and control board. Performs forced cooling of the board,
Not only is the device lightweight and compact, but it is also economical.

Furthermore, if the charger is also configured to be forcibly cooled by an upper fan, it will be easier to diffuse ozone, which has a pungent odor, generated on the charger side. This eliminates the possibility of causing discomfort to the printer operator.

〔Example〕

Hereinafter, the present invention will be explained based on one embodiment of the drawings. FIG. 1 is a vertical sectional view showing the overall internal structure of an electrophotographic printer according to the present invention, and FIG. 2 is a longitudinal sectional view of the printer shown in FIG. 1. It is an external perspective view.

In FIG. 2 showing the appearance of the printer of the present invention,
Reference numeral 1 denotes a printer main body, and transfer paper 2 is fed from a paper feed tray (or paper feed cassette, hereinafter referred to as paper feed tray) 3 located on the top surface of the printer main body 1, and transfers and fixes a toner image. After that, the paper is ejected from the paper ejection tray 4 on the front side.

Here, the electrophotographic process of the printer shown in FIG. 2 will be explained based on FIG. It is carried out. That is, 9 is a charger that charges the photoreceptor 8, 10 is an exposure source consisting of a laser beam, an LED, etc. that exposes the photoreceptor 8 charged by the charger 9;
11 is a developing device that develops the electrostatic latent image formed on the photoreceptor 8 by exposure with the exposure source 10 as a toner image; 12 is a transfer device that transfers the toner image on the photoreceptor 8 onto the transfer paper 2; and 13 14 is an eraser for erasing the electrostatic latent image on the photoconductor 8, and 14 is a cleaner for removing the developing toner remaining on the photoconductor 8 after transferring the toner image on the photoconductor 8 to the transfer paper 2. It shows.

In the above configuration, the transfer paper 2 is stored in the paper feed tray 3 which is removably arranged on the top surface of the printer main body 1, and is separated and fed one by one by the separation paper feed mechanism 5. After, registration roller 6
The toner image on the photoreceptor 8 is transferred by the transfer device 12, and then thermally fixed by the fixing device 7, and then transferred to the front surface of the printer body 1. The paper is discharged onto a paper discharge tray 4 which is removably disposed in the paper tray 4.

Reference numeral 21 indicates an upper transfer guide disposed between the transfer device 13 and the fixing device 7, 22 indicates an upper transfer fan,
The upper transfer guide 21 is attached to the back surface of a front cover 19 that is located on the top surface of the printer body and can be opened and closed. In addition, the upper transfer fan 2
2, the non-toner image side of the transfer paper 2 contacts the above-mentioned upper transfer guide 21, that is, the upper transfer guide 21 disposed between the transfer device 13 and the fixing device 7, and is conveyed to the fixing device 7 side. Air is discharged from the upper transfer fan 22, and the toner image side of the transfer paper 2 is pressed by the wind pressure of this air. In addition,
In FIG. 1, the flow of air by the upper transfer fan 22 is indicated by arrow A.

The air circulation duct 26 of the printer body 1 is provided with an opening 24 that is located on the air inflow side of the upper transfer fan 22 and communicates with a charger 9 that generates ozone by charging. In addition, the printer body 1
The air circulation duct 26 also has an opening 25 located on the air inflow side of the upper transfer fan 22 and communicating with the power source 17 and the control board 18, which are heat sources.
is provided, and the ozone generated in the charger 9 and the heat generated in the power supply section 17 and the control board 18 are forcedly ventilated by the air flow shown by arrows C to I in FIG.

The air discharge port 23 of the upper transfer fan 22 is partially constituted by the radiation guard 16 of the fixing device 7, and the air discharged from the upper transfer fan 22 forces the radiation guard 16 of the fixing device 7. After cooling, the toner image side of the transfer paper 2 is pressed by the wind pressure, and then flows as shown by arrow B in FIG. is discharged to the outside.

When using a laser beam as the exposure source 10, it is effective to make optical lenses and reflective mirrors made of plastic in order to make them lightweight, compact, and low-cost. Compared to optical glass lenses and reflectors, its thermal expansion coefficient is an order of magnitude larger, and it suffers from a lack of dimensional stability. Therefore, the exposure source 10
When using a laser beam as a laser beam, the plastic lens or reflecting mirror is placed below the photoreceptor 8, which is located at approximately the center height of the printer body 1, so that the inside of the printer body 1 is not affected when the printer is in use. It is better to make it less susceptible to temperature rise.

In the above configuration, the transfer paper 2 to which the unfixed toner image is attached by the transfer device 13 is pressed by the wind pressure of the air discharged from the upper transfer fan 22, and the toner image side of the transfer paper 2 is pressed. The non-toner image side of No. 2 is conveyed to the fixing device side in contact with the upper transfer guide 21, and it is possible to prevent the unfixed toner image from being rubbed, and as mentioned above, in an electrophotographic printer, The unfixed toner image attached to the transfer paper is attracted to the transfer paper with a Coulomb force approximately 1000 times the weight of the toner, so the individual toner particles constituting the toner image are attracted to the transfer paper with a Coulomb force approximately 1000 times the weight of the toner. Even if wind pressure is applied from the upper transfer fan 22 against its own weight, the unfixed toner image will not be disturbed.

According to the embodiment, the transfer paper 2 passes through the upper part of the printer main body 1, instead of the configuration in which the transfer paper passes through the lower part of the printer main body, as in conventionally generally proposed electrophotographic printers. With this configuration, the paper path within the printer body 1 is shortened, and the frequency of paper jams and skews that may occur during paper transport can be reduced compared to the conventional art.

Furthermore, according to the embodiment, even if a paper jam should occur, the paper jam can be disposed of by simply opening the front cover 19 as shown by the dashed line (19'), and maintenance of the paper feeding path can be carried out. can be done extremely easily. Further, according to the embodiment described above, maintenance can be easily performed from the top surface of the printer main body 1, such as removing and replacing the photoreceptor 8 and replenishing toner. For example, to remove the photoconductor 8 from the printer main body 1, open the front cover 19, rotate the photoconductor 8 around its rotation center 20, and then pull out the photoconductor 8 upwards. The photoreceptor 8 can be attached to the main body 1 by performing the above-described operations in reverse. Toner reinforcement can also be achieved by replacing the toner cartridge 15 from the top of the printer main body 1. As a result, it is no longer necessary to replace consumables, such as a photoreceptor, from the side of the printer body, unlike conventional printers that employ a clam shell structure. In other words, as in the conventional case,
When using the printer, it does not require a large space to install the printer, as consumables can be pulled out from the side of the printer and removed, and the area required for printer installation is kept smaller than before. be able to.

Note that, as shown in the illustrated embodiment, if the transfer paper 2 is fed from the top of the printer main body 1 instead of from the side surface of the printer main body 1, the paper feed tray 3 can be fed from the top of the printer main body 1. Since it does not protrude to the sides, the area required for installing the printer can be further reduced to a small space.

By the way, the power supply section 17 has a heat output of approximately 70W, and the control board 18, which controls the sequence operation of the electrophotographic process and the interface function with the host, has a heat output of approximately 60W. If the upper transfer fan 22 is configured to forcibly cool the power supply section 17 and the control board 18 as in the illustrated embodiment, not only the photoreceptor 8 but also the developing unit 1
The power supply section 1, which is a heat source, can be prevented as much as possible from heating deterioration of materials that are sensitive to high temperatures, such as toner built into the power supply section 1.
7 and the control board 18, instead of using a dedicated fan to cool the power supply unit 17 and the control board 18, the fan used to prevent the unfixed toner image from being rubbed can also be used.
It performs forced cooling, which not only makes the equipment lighter and more compact, but also has excellent economic efficiency.

Furthermore, as shown in the illustrated embodiment, if the charger 9 is also configured to be forcibly cooled by the upper transfer fan 22, it is possible to easily diffuse ozone with an irritating odor generated on the charger 9 side, and to This eliminates the possibility of causing discomfort to the printer operator due to the presence of a strong irritating odor.

〔Effect of the invention〕

The present invention is as described above, and as is clear from the description of the illustrated embodiments, according to the present invention, a toner image is transferred to the lower side of the transfer paper, and the transfer paper is conveyed to the fixing device in this posture. This eliminates rubbing of unfixed toner images and reduces the space required to install the printer.In addition, even if a paper jam occurs, it is easy to dispose of the paper jam. Moreover, without using a dedicated fan to cool the power supply unit and control board, which are heat sources, the fan used to prevent image scratching can also be used to forcibly cool the power supply unit and control board. Not only does it make the equipment lighter and more compact, it is also economical, and it also makes it easier to diffuse ozone, which has a pungent odor, that is generated on the charger side. Thus, an improved electrophotographic printer that does not cause discomfort to the printer operator can be obtained.

[Brief explanation of the drawing]

The drawings show an embodiment of an electrophotographic printer according to the present invention, and FIG. 1 is a longitudinal sectional side view showing the overall internal structure thereof, and FIG. 2 is an external perspective view of the printer shown in FIG. 1. 1...Printer main body, 2...Transfer paper, 3...Paper feed tray, 4...Paper output tray, 7...Fuser, 8
...Photoreceptor, 9...Charger, 10...Exposure source, 1
DESCRIPTION OF SYMBOLS 1...Developer, 12...Transfer device, 15...Toner cartridge, 17...Power unit, 18...Control board, 19...Front cover, 21...Upper transfer guide, 22...Upper transfer fan , 24 and 2
5...Opening, 26...Air distribution duct.

Claims (1)

[Scope of Claims] 1. A latent image formed on a photoreceptor by being charged with a charger and exposed with an exposure source is converted into a toner image by a developing device, and the toner image on the upper part of the photoreceptor is transferred by a transfer device. In an electrophotographic printer that transfers onto paper and conveys the transfer paper with an unfixed toner image to a fixing device, the toner image on the upper part of the photoreceptor is transferred to the lower side of the transfer paper, and the unfixed toner image is transferred to the lower side of the transfer paper. The attached transfer paper is conveyed from the upper transfer fan so that the upper side of the transfer paper, which is the non-toner image side, contacts the upper transfer guide placed between the transfer device and the fixing device and is conveyed to the fixing device side. The toner image side of the transfer paper is pressed by the wind pressure of the ejected air, and the unfixed toner image on the transfer paper, which has been conveyed to the fixing device side as described above, is
In addition to fixing onto the transfer paper with the fixing device, a
An air circulation duct is provided that has an opening that communicates with the power supply unit, the control board, and an opening that communicates with the charger that generates ozone when charged, and the paper feed section of the paper feed tray relative to the printer body is connected to the top surface of the printer body. , the toner cartridge is arranged to be replaceable from the top surface of the printer body, and the upper transfer guide is attached to the back surface of a front cover that is located on the top surface of the printer body and can be opened and closed. photo printer.