JPS6373283A - Image forming device - Google Patents

Abstract

PURPOSE:To suppress the occurrence of image running without excessively raising the surface temperature of an image carrier even in a high-humidity environment by providing a member which rubs the surface of the image carrier and a forcibly ventilating means of an electrifier. CONSTITUTION:An elastic body roll where a sponge layer 12 and a silicone rubber layer 13 are laminated in order on the peripheral surface of a magnet roll 11 fixed to a shaft 10 is used as a rubbing member 8b, and the peripheral surface of this member 8b is always pressed to a photosensitive body 1. Forcibly ventilating means 51 and 71 are provided for a post electrostatic charger 5 and a separating electrostatic charger 7. An amorphous silicon is used as materials of the photosensitive body 1, and the copying process is performed by plus electrification in a primary charger 2. Since much corona products such as ozone are produced by, especially, minus electrification and AC electrification, forcibly ventilating means 51 and 71 are used to suppress the occurrence of image running.

Description

DETAILED DESCRIPTION OF THE INVENTION 42 OBJECTS OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming apparatus. More specifically, the present invention relates to an apparatus for forming an image on an image carrier such as a photoreceptor or dielectric by a known image forming process such as electrophotography or electrostatic recording.

[Conventional technology]

This type of image forming apparatus forms a transferable toner image on the surface of an image carrier and then transfers it to a transfer material, and it is necessary to sufficiently remove the toner remaining on the surface of the image carrier after transfer. be.

In addition, in the image forming apparatus described above, corona products such as ozone generated by high-voltage equipment in the apparatus such as a corona discharger, and foreign substances such as talc and rosin released from transfer materials such as paper are removed. Unlike toner, such foreign matter is difficult to remove with a cleaning blade or the like, and in a high-humidity environment, it absorbs moisture and lowers the resistance on the surface of the image carrier, resulting in so-called image deletion. .

Therefore, in addition to a toner removal means such as a cleaning blade or a fur brush in the cleaning device, there is a method in which the surface of the image carrier is rubbed with a rubbing member made of an elastic material such as silicone rubber to mainly clean foreign substances other than toner. has already been proposed.

(Problems to be Solved by the Invention) However, for example, when amorphous silicon is used as a photoreceptor, image deletion is likely to occur particularly in a high humidity environment (e.g. room temperature of 33° C. and humidity of about 85%). Even if the above-mentioned rubbing member is used, image deletion may not be suppressed unless the surface temperature of the image carrier is heated to approximately 45°C using a heating means such as a drum heater. When kept at the above temperature, there is a problem in that phenomena such as toner fusion and caking cloudy blade marks often occur.

The present invention has been proposed in view of the above problems, and an object of the present invention is to provide an image forming apparatus that can prevent image deletion without significantly increasing the surface temperature of an image carrier.

SUMMARY OF THE INVENTION [Means for Solving Problems] The present invention provides an image forming apparatus having a heating means for an image bearing member, a member that contacts the surface of the image bearing member and rubs the surface, and a charging member. and forced ventilation means for the device.

[For production]

By providing a member that rubs the surface of the image carrier and a forced ventilation means for the charger, corona products, moisture, and foreign substances such as talc that accumulate or adhere to the peripheral surface of the image carrier are removed. Therefore, the occurrence of image deletion is suppressed without excessively increasing the surface temperature of the image carrier.

〔Example〕

FIG. 1 is a schematic diagram illustrating the main parts of an electrophotographic copying machine as an image forming apparatus. In FIG. Exposure section 3, developer 4, post charger 5. Transfer charger 6,
Separation charger7. Known image forming process equipment such as a cleaning device 8 is arranged in sequence. Further, inside the photoreceptor 1, a photoreceptor heating means (not shown) such as a sheathed heater or a surface heating element is provided.

The photoreceptor l rotates in the direction indicated by the arrow in the figure, and the charger 2
After being uniformly charged, an optical image is exposed in the exposure section 3 to form an electrostatic latent image. The electrostatic latent image is developed with toner by a developing device 4 to become a transferable developed image, which is transferred onto a transfer material 9 by a transfer charger 6.

After the transfer, the transfer material 9 is separated from the photoreceptor 1 by the separation charger 7, and is discharged to the outside of the apparatus via a fixing device (not shown).

On the other hand, the toner remaining on the photoconductor 1 without contributing to the transfer is
As the photoreceptor l rotates, it reaches the cleaning device 8.

The cleaning device includes a cleaning blade 8a,
Residual toner and other foreign matter are scraped off by these members, stored in the cleaning device, and discharged to the outside by a screw conveyor as necessary.

Embodiment 1 (FIGS. 2 and 3) As the above-mentioned rubbing member 8b, in this example, as shown in FIG. 13 is used, and the circumferential surface of the elastic roller is in constant pressure contact with the photoreceptor 1.

In addition, amorphous silicon is used as the photoreceptor 1,
- The charger 2 performs the copying process with a positive charge. Since a large amount of corona products such as ozone are produced especially in negative charging and AC charging, if forced ventilation means is used in these chargers, it is possible to suppress the occurrence of image deletion. Therefore, in this embodiment, as shown in FIG. 2, forced ventilation means 51 and 71 are installed in the post charger 5 and the separation charger 7. Each of the ventilation means 51-71 is provided with an air suction fan on the side opposite to the photoconductor 1 of the shield member 5a and fist 7a surrounding the charged wire, and removes corona products and the like accumulated in the shield members 5a and 7a out of the device together with air. An example is shown in which the data is discharged.

With the above configuration, it is possible to suppress the concentration of corona products such as ozone, which are generated particularly in large quantities in the negative chargers 5 and 7, to a low level, so that the elastic body as the rubbing member 8b can be kept low. Even if the contact pressure of the roller against the photoreceptor 1 and the surface temperature of the photoreceptor 1 are lowered, it is possible to reduce the occurrence of image deletion. Therefore, it is now possible to suppress the occurrence of toner fusion to the photoreceptor, caking, blade marks, etc. caused by the above-mentioned high temperatures.

As mentioned above, the elastic roller shown in FIG. 3 is used as the sliding member 8b, and the post charger 5 and the separation charger 7 are used in a high temperature and high humidity environment with and without forced ventilation means 51-71. Table 1 shows the surface temperature of the photoreceptor required to suppress the occurrence of image deletion at a room temperature of 33° C. and a humidity of 85%.

Table 1 As is clear from the above results, if the elastic roller shown in FIG. It has been found that image deletion does not occur if the temperature is slightly higher than room temperature.

Note that if the contact pressure of the elastic roller against the photoreceptor is set to be strong, the strong sliding force will cause the photosensitive layer on the surface of the photoreceptor to wear out and accelerate deterioration, so it is recommended to set the contact pressure to be weaker. Table 2 shows the amount of wear of the photosensitive layer when the contact pressure is preferably set to 15 g/cm and when it is set to 45 g/cm.

Table 2 It was found that even if the contact pressure was set low (15 g/c) as described above, image blurring did not occur because the chargers 5 and 7 were provided with forced ventilation means 51 and 71.

Embodiment 2 (FIGS. 2 and 4) In this example, a shaft 10 is used as the sliding member 8b as shown in FIG.
A magnetic roller 14 fixed to the magnetic roller 14 and magnetic particles 15 attracted by the magnetic force were used. The other configurations are the same as in the previous example. Reference numeral 16 in FIG. 4 indicates a cutting plate for the magnetic particles 15.

In this embodiment as well, since forced ventilation means 51 and 71 are provided in the negative charger 5 and 7, it is possible to suppress image blurring at a relatively low temperature.

As described above, the magnetic roller 14 and magnetic particles 15 shown in FIG. Table 3 shows the surface temperature of the photoreceptor required to suppress the occurrence of image deletion at a room temperature of 33° C. and a humidity of 85%.

Table 3 As is clear from the above results, the fourth sliding member 8b
If the magnet roller 14 and magnetic particles 15 shown in the figure are used and the chargers 5 and 7 are provided with forced ventilation means 51 and pot 71, the surface temperature of the photoreceptor can be kept at about 40°C even in a high temperature and high humidity environment. It was found that no image blurring occurred. Note that at the above temperature, toner fusion blocking, blade marks, etc. do not occur.

Furthermore, the sliding member 8b of this example has the advantage that since the magnet roller 14 is not in direct contact with the photoconductor 1, but is in contact with the photoconductor 1 through the magnetic particle layer 15, there is almost no wear on the surface layer of the photoconductor. There is.

Embodiment 3 (FIG. 5) In this example, a measuring means 17 that measures the humidity or temperature and humidity of the environment in which the image forming apparatus is used, and a control device that controls the forced ventilation means 51 and 71 according to the measured values are used. 18
For example, in a low-humidity environment where image blurring is less likely to occur, the air suction force of the forced ventilation means can be weakened or stopped to minimize contamination of the charging wires of the chargers 5 and 7.

C. Effects of the Invention The present invention provides a member that rubs the surface of the image carrier and a forced ventilation means for charged l as described above, thereby generating corona that remains or adheres to the circumferential surface of the image carrier. objects and moisture,
In addition, since foreign substances such as talc are removed, image deletion can be suppressed without excessively increasing the surface temperature of the image bearing member even in a high humidity environment. Therefore, it is possible to prevent the above-mentioned toner fusion, blocking, blade marks, etc. caused by raising the surface temperature of the image bearing member to a high temperature.

[Brief explanation of the drawing]

FIG. 1 is a diagram schematically illustrating the configuration of an image forming apparatus, FIG. 2 is a diagram showing the image forming apparatus a to which the present invention is applied, FIG. 3 is a side view showing an example of a sliding member, and FIG. A side view of the sliding member,
FIG. 5 is a schematic structural explanatory diagram of an image forming apparatus according to another embodiment. 1 is an image carrier, 5 is a post charger, 7 is a separation charger, 5
1 and 71 are forced ventilation means, 8 is a cleaning device, and 8b
is a rubbing member.

Claims (3)

[Claims] (1) In an image forming apparatus having a heating means for an image carrier, a member that comes into contact with the surface of the image carrier and rubs the surface;
An image forming apparatus comprising: forced ventilation means for a charging device. (2) The image forming apparatus according to claim (1), wherein the sliding member is an elastic roller pressed against the image carrier. (3) The image forming apparatus according to claim (1), wherein the sliding member comprises a magnetic roller disposed close to the image carrier and magnetic particles attracted by the magnetic force of the magnetic roller. .