JPS6010286A - Recording device - Google Patents

Abstract

PURPOSE:To enable use of photosensitive material constituting a photosensitive body low in heat resistance, suppress thermal deterioration and miniaturize a copying machine by containing heat radiating liquid in a photosensitive drum and radiating heat. CONSTITUTION:A heat pipe 51 is provided in the lower part of the photosensitive drum 9. When the temperature of liquid contained in the drum 9 is raised, working liquid in the heat pipe 51 is evaporated, and the vapor goes in the direction of the arrow 60 and arrives at a condensation section 54. The condensation section 54 is provided with heat radiating fins 53 and cools and condenses the vapor and liquifies. Liquified working liquid returns to the evaporation section 56. The above-mentioned process is repeated while the evaporation section 56 is heated. In regard to drive rotation of the drum 9, a belt 61 is stretched on a boss 10a provided on the outer end face of the drum 9 as shown by broken lines, and driven by a motor M. By this way, a heating fixing section can be provided close to the drum 9, and the copying machine can be miniaturized.

Description

DETAILED DESCRIPTION OF THE INVENTION 1. Field of Industrial Application The present invention relates to an improvement in a recording apparatus that has a heat source such as a heat fixing device around a photoreceptor drum, and the photoreceptor tends to be heated by the heat.

2. Prior Art First, an outline of a conventional recording apparatus using a photosensitive drum will be described using a scanning exposure type electronic four-photo copying machine as an example. When a copy document is placed on the document table and a copy button is pressed, an exposure lamp illuminates the document and travels in a predetermined direction together with an optical system including a reflecting mirror.

Reflected light corresponding to the density of the original is irradiated onto the uniformly charged photoreceptor drum via the optical system, and an electrostatic latent image is formed on the photoreceptor drum. Furthermore, a toner image corresponding to the density of the original is formed on the photoreceptor drum by the developer.

On the other hand, a recording medium (for example, copy paper) is fed from a paper feeder so as to match the position of the toner image on the photoreceptor drum, and comes into contact with the photoreceptor drum. Then, the toner image formed on the surface of the photoreceptor drum is gradually transferred to a transfer type. Thereafter, the copy paper onto which the toner image has been transferred is separated from the photoreceptor drum, and the copy paper is sent to the 4-2 fixing device. The P-Ra fixing device is composed of two 4-Ras, at least one of which is a heated roller, and heats and fixes an image formed by a developer onto copy paper. Thereafter, the copy paper is discharged out of the main body of the copying machine.

On the other hand, the photosensitive drum is cleaned to remove excess toner powder after the visible toner image is transferred to the copy paper, and this process is repeated every time recording is performed.

However, when a toner image formed on a photoreceptor drum is electrostatically transferred onto a copy paper using a transfer electrode such as a corona discharger as in the past, disturbances in the electric field that occur during transfer and separation cause the transfer The resulting toner image is disturbed and the resolution of the toner image is reduced. Furthermore, stable transfer to plain paper is not possible under high humidity conditions due to a decrease in the resistivity of the paper.

Furthermore, when a conductive magnetic toner or the like from which a high-quality toner image is obtained is used as a toner, a situation arises in which transfer is virtually impossible.

As a method to improve the above-mentioned drawbacks of electrostatic transfer, a method of suppressing transfer onto a transfer sheet using a suppression μm teller has been attempted, but Matsumoto's efficiency is poor and only about half the amount of toner image is transferred. There are other obstacles such as:

Japanese Patent Publication No. 48-22763, Japanese Patent Publication No. 49-7855
No. 9 and U.S. Patent No. 3.993.825, etc., the above-mentioned toner image is pressure-transferred to an intermediate transfer member having a rubber transfer layer, and the transferred toner image is transferred using a heat roller. A method of press-transferring and e-fixing (transfer fixing) onto copy paper while heating and melting the toner has been proposed. In such a method, a toner image is pressed and transferred onto the surface of a rubber-based transfer layer, such as silicone rubber or fluorine rubber, which has releasability on the one hand and has the property of adhering fine particles when pressed. The toner image on the transfer layer is heated and melted by contact with a heating body such as a heat roller, and is simultaneously pressed and transferred onto a fed copy paper and fixed. That is,
Upon heating, the molten toner image is easily transferred and fixed onto the copy paper based on the above-mentioned releasability of the transfer layer.
The company claims that there is no reduction in the resolution of the toner image during the transfer process, and the transfer is achieved at a high transfer rate.

In a recording device using an intermediate transfer member, in order to suppress and transfer the toner image formed on the photoreceptor drum to the intermediate transfer member, the photoreceptor drum and the intermediate transfer member must be in sufficient contact with each other, and In order to transfer and fix the toner image on the transfer member again onto copy paper, it is generally necessary to heat the suppressing intermediate transfer member to a temperature near or above the toner melting temperature. Direct contact with the photoreceptor drum tends to increase the temperature of the photoreceptor drum.

If the suppression intermediate transfer member is, for example, in the form of a roll and has a heat source inside, the photoreceptor drum may become extremely hot.

On the other hand, the characteristics of photoreceptors generally tend to change easily due to the influence of heat, and heat can cause phenomena such as deterioration of the physical properties of the photoreceptor.

For example, phenomena such as changes in photosensitivity characteristics due to changes in temperature, permanent deterioration of crystallization due to temperature rise in the case of Se-based photoreceptors, or a decrease in dark decay characteristics due to temperature rise, that is, a decrease in acceptance potential, may occur. Resulting in. Due to these reasons, it becomes impossible to obtain an image with a desired density. Additionally, when the temperature of the photoreceptor increases, the toner on the photoreceptor drum comes into contact with the suppression intermediate transfer member which is maintained at a high temperature during suppression transfer, so the temperature of the toner increases, and the toner is transferred from the photoreceptor drum to the intermediate transfer member. A phenomenon occurs where the image is not transferred to the photoreceptor drum and remains on the photoreceptor drum. This is determined by the temperature of the toner in the suppression transfer section, which is expressed by a binary linear equation that is proportional to the maintenance temperature of the intermediate transfer member and the temperature of the photoreceptor drum. Therefore, in order to maintain stable transfer performance, it is important to have a technique for lowering the temperature of the intermediate transfer member immediately before the suppression transfer and a technique for preventing the temperature of the photoreceptor from rising. From the above, it is important to suppress the rise in temperature of the photoreceptor in order to maintain stable characteristics and transfer performance of the photoreceptor.

Therefore, heat dissipation fins were installed on the inner surface of the photoreceptor drum, and a blower installed outside the photoreceptor drum was used to apply forced cooling air to the heat dissipation fins to cool them and prevent the temperature of the photoreceptor from rising. In this method, increasing the number of heat dissipating fins provided on the photoreceptor drum in order to improve cooling efficiency poses problems in terms of production technology and production cost, and increasing the amount of cooling air increases noise. Next, due to the design, it is difficult to arrange ducts, intake/exhaust devices, etc. to provide a blower outside the photoreceptor drum to blow air inside the photoreceptor drum. However, this method was limited to air cooling, and there were certain limits to achieving high cooling efficiency. For this reason, the life of the photoreceptor drum is short, and it is necessary to replace it with a new one within a short period of time.

3. Object of the Invention An object of the present invention is to provide a heat source around the photoreceptor drum, for example, a portion of the photoreceptor drum is in direct contact with a member maintained at a high temperature such as a suppressed intermediate transfer member, thereby transferring high heat. It is an object of the present invention to provide a device that can extend the life of a photoreceptor even when exposed to high temperatures due to radiant heat from a heat source or the like. Another object of the present invention is to provide a device that uses an intermediate transfer member and has stable transfer performance.

4. Structure of the Invention In other words, the present invention provides a recording apparatus in which a heating section is provided near the outer periphery of a photoreceptor drum, in which a liquid is accommodated in at least a part of the inner space of the photoreceptor drum, and the heat of the liquid is A recording apparatus characterized in that an evaporating part of the heat pipe is arranged inside the photoreceptor drum and a condensing part thereof is arranged outside the photoreceptor drum in order to absorb and release the heat pipe. It is.

5. Examples Hereinafter, examples of the present invention shown in the drawings will be described in detail.

FIG. 1 schematically shows an example of a suppression transfer type electrophotographic copying machine incorporating an example of a photosensitive drum cooling means according to the present invention.

In this copying machine, an original 4 covered with a platen cover 3 is placed on a glass original placing table 2 provided on the upper wall of the main body, and a light source 5 in the main body illuminates the original 4. is irradiated through a slit 50 provided in the earthen wall of the main body, and the reflected light is transmitted to 5LA (Selfoc Lens Array) 7.
After being reflected by a mirror 8, the light is incident on a photosensitive drum 9. Therefore, the photosensitive layer 10 made of selenium, organic photoconductive material, etc. on the drum 9 is exposed to image light in a pattern corresponding to the original image by moving the original table 2 in the direction of the arrow, and the photosensitive layer 10 made of selenium, an organic photoconductive substance, etc. A latent image is formed. Reference numeral 11 in the figure is a corona charger, which charges the entire surface of the photosensitive layer to a predetermined polarity in a beam exposure state. Reference numeral 12 denotes a device consisting of a light emitting diode array or an electroluminescent plate for preventing black frames, which eliminates the charge on the non-image area on the photoreceptor and prevents toner from adhering to the non-image area. There is work. A known conductive magnetic toner 14 is supplied from a developing sleeve 13 to the photosensitive drum 9 on which the electrostatic m-image is formed. This toner 14 is conveyed on the sleeve 13 while its thickness is regulated by a magnetic roll 15 for toner thickness regulation, and the conveying force is applied by the rotation of the sleeve 130 and the rotation of the magnet roll 16 inside the sleeve 13. . Since a reverse charge is induced in the toner 14 by the electrostatic latent image on the photoreceptor drum 9, the toner particles sequentially move onto the photoreceptor drum 9 in proportion to the amount of charge of the electrostatic latent image and are attracted to the photoreceptor drum 9. A toner image of a predetermined pattern is formed thereon, and development is performed.

The toner image thus formed is then transferred to the intermediate transfer roller, which is in contact with the photoreceptor drum 9 at a linear pressure of 1.0 to 9 folds/cn1 or less (for example, 0.4 to 9 folds/crn). It is pressed and transferred to 1. Since this roll 1 has a surface layer mainly composed of a mixture of silicone rubber and fluorosilicone rubber, it sufficiently peels off the toner particles on the photoreceptor drum 9. The peeled toner particles are transferred to roll 1
The material is preheated to a predetermined temperature (that is, a temperature that exhibits sufficient mold releasability) by a heater lamp 17 inside the roller 1, and is transported to the next pressure roll 18 on the roll 1. The pressure bonding wheel 18 is heated to a predetermined temperature by an internal heater lamp 19, and heats the copy paper U that is fed from the paper feed box 20 to the paper feed roll 21 via the guide plate 37, 22 and the conveyance roller 23. while feeding it between rolls 1 and 18.

Therefore, the copy paper 24 has a temperature sufficient to transfer the toner image, and when it is fed between the rolls 1 and 8, the preheated toner image is separated from or transferred from the roll 1. At the same time, the toner image can also be fixed on the copy paper U. In addition, 25 in the figure is the pressure roll 1
8, a cleaning roller; 26, a cleaning roller for the intermediate transfer roll 1; 27, a guide plate for feeding the fixed copy paper to a paper discharge roller 29 on the tray 28 side;
30 is a roller for feeding out the copy paper from the bottom of the tray 28 during double-sided copying, and 31 is a guide plate for double-sided copying.

At the subsequent stage of the intermediate transfer roller 1, the photosensitive drum 9 is irradiated with light from a discharge lamp 32 to erase the residual charge on the drum. Further, a cleaning member 34 made of, for example, a rubber roller is brought into contact with the photoreceptor drum 9, and the remaining toner particles separated by the cleaning member 34 are removed by a scraping blade (not shown) into a cleaning device 35. It will be stored.

What should be noted in a copying machine configured as above is that
A liquid (for example, silicone oil) 55 is inside the photoreceptor drum 9.
An evaporating section 56 of the heat pipe 51 is provided inside the photoreceptor drum 9, and a condensing section 54 thereof is provided outside the photoreceptor drum 9 in order to absorb and release the heat of this liquid 55. That's true. Hereinafter, this effect will be explained in detail.

In the copying machine shown in FIG. 1, the intermediate transfer body 1 is constructed in the form of a roll, and has a heater 7 inside thereof.

As the photoreceptor drum 9 moves, the photoreceptor drum 9 is heated by the heat of the intermediate transfer roll 1, and the temperature of the liquid 55 contained in the photoreceptor drum 9 also rises. As shown in FIG. 2, a heat pipe 51 is arranged on the lower side of the photoreceptor drum 9.
When the temperature of the liquid stored in the heat vibrator 5 increases,
The working fluid in 1 evaporates, and the vapor heads in the direction of arrow 60 and reaches condensation section 54 . The condensing section 54 is provided with radiation fins 53, where the steam is cooled and condensed to become liquid. The working fluid that has become a liquid returns to the evaporator 56, and this process is repeated while the evaporator 56 is being heated.

? The rotation of the drum binding is achieved by hanging a belt 61 on the boss portion 10a extending on the outer end surface of the drum as shown by the broken line.
This can be done by driving the motor M.

A schematic diagram of the heat pipe 51 is shown in FIG.

The heat pipe 51 is composed of a container 57, a quick 58, and a working fluid, and has a vapor space 59 in the center thereof.

Here, when the evaporation section 56 of the heat pipe 51 is heated, the working fluid impregnated in the wick 58 evaporates, becomes vapor, moves through the vapor space 59, and is cooled in the condensation section 54.
It is condensed, becomes a liquid, and returns to the evaporation section 56 by the capillary force of a wick (a structure with a large capillary force) 58 on the inner wall of the container 57. The heat pipe 51 plays the role of heat transfer by dissipating the heat absorbed in the evaporating part 56 in the condensing part 54, and its thermal conductivity is hundreds of times higher than that of copper of the same shape. Since the condensed working fluid returns to the evaporator 56 by the capillary force of the quick 58, heat can be easily transferred even when the condenser 54 is located lower than the evaporator 56.

Therefore, even if the liquid 55 contained in the photoreceptor drum 9 is heated by the intermediate transfer member 1, this heat is transferred to the heat pipe 5.
1, heat is not immediately radiated to the outside of the photoreceptor dome 9, and the temperature rise of the photoreceptor layer formed on the circumferential surface of the photoreceptor drum 9 can be suppressed. The heat pipe can be freely bent between the evaporating section of the heat pipe 51 and the condensing section 54, and the heat dissipation section can be freely installed at the most suitable position.

Conventionally, heat dissipation fins were attached inside the photoreceptor drum 9,
The photoreceptor drum was cooled by sending cooling air through the proa, but this method required air cooling, and as mentioned above, there were various problems in increasing the cooling efficiency. there were.

However, in the embodiment of the present invention, the liquid 5 is placed on the photoreceptor drum 9.
This liquid transfers the heat of the photoreceptor dome 9 to the evaporation section 56 of the heat pipe 51. A liquid has a much higher thermal conductivity than a gas such as air, and the heat of the liquid 55 is transferred to the outside of the photoreceptor drum 9 by the heat pipe 51. As the length of the heat pipe 51 increases, the position of the condensing section 54 can be changed so that a location where heat can be easily dissipated inside and outside the copying device can be selected, and the heat dissipation fins 53 can be arranged in a high density, unlike the conventional example. Cooling air can be flowed through the radiation fins 53 without using complicated ducts, and highly efficient cooling has become possible.

The drawing shown in FIG. 2 shows an embodiment in which liquid is contained in a part of the inner space of the photoreceptor drum 9, but as shown in FIG. 55, and the heat pipe 51 may be arranged so as to penetrate through the center of the photoreceptor drum 9.

In this case, the cooling efficiency will be increased if the fins 52 are made larger as shown in FIG. 4 so that the heat of the liquid can be easily transferred to the evaporation section 5G of the heat pipe 51. In addition, in consideration of properties, silicone oil or fluorine-based inert liquid (Floner FC-43, FC-70 manufactured by 3M Company) is preferable.

Of course, the structure is such that the liquid inside the drum does not leak out of the drum.

In the embodiments, the present invention has been described with respect to a copying apparatus using the intermediate transfer member 1, but the present invention can be further modified based on the technical idea. Even in copying machines that directly transfer images onto copy paper, in order to make the machine more compact, the heat fixing unit may have to be placed close to the photoreceptor drum, and in such cases, the heat of the heat fixing unit naturally It becomes easier to be transmitted to the photoreceptor drum. Therefore, as explained in the above embodiment, if the photoreceptor drum 9 is cooled and the friction force Ω is reduced, providing the heat-reducing fixing section in the vicinity of the photoreceptor drum 9 does not pose any problem. It is easy to make the machine compact.

6. Effects of the Invention Conventionally, the photoreceptor drum was cooled by blowing cooling air directly to the radiation fins of the photoreceptor drum, but there was a natural limit to increasing the cooling efficiency due to air cooling.

For this reason, the photosensitive material constituting the photoreceptor is limited to heat-resistant materials, and the photoreceptor drum reaches a high temperature, resulting in a short lifespan of the photoreceptor.

However, if the photoreceptor drum is cooled as shown in the present invention, it is possible to use the photoreceptor even if the photoreceptor has poor heat resistance, and the photoreceptor is also less likely to deteriorate due to heat. The lifespan has also become longer.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention, in which FIG. 1 is a schematic cross-sectional view of a suppression transfer type electrophotographic copying machine, FIG. 2 is a schematic cross-sectional view of a photosensitive drum and a heat nozzle, and FIG. () and (b) are respective sectional views in the length direction and radial direction of the heat tube, and FIG. In addition, in the symbols used in the drawings,
- One photosensitive drum 51 ------- Heat pipe 52, 53 ------- Fin 54 - One condensing section 55 - Part Body 56 ---- ---One evaporation part. Agent Attorney Hiroshi JIX (1 other person) No. 30 (8) (b) et al. 1 58 58

Claims (1)

[Claims] 1. In a recording device in which a heating section is provided near the outer periphery of a photoreceptor drum, a liquid is accommodated in at least a part of the inner space of the photoreceptor drum, and a heat source is used to absorb and release the heat of the liquid. A recording apparatus characterized in that an evaporating section of the pipe is arranged inside the photosensitive drum, and a condensing section of the pipe is arranged outside the photosensitive drum.