JPS60262183A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent an image carrier from damaging by incorporating poly- vinylidene fluoride powder in the surface of a roll which is provided to wipe out toner particles remaining on the surface of the image carrier even after transfer and has the surface formed of a porous elastic body. CONSTITUTION:The image carrier 1 passed through a transfer process at an unshown part is rotated as shown by an arrow Z and a roll 91 which rotates in the opposite direction A of the direction Z is rubbed against the carrier 1. The roll 91 has the porous elastic body 93 made of sponge, etc., around a cylindrical shaft 92 and also rubbed against a magnet roll 94. The elastic body 93 on the surface of the roll 91 contains powder 11 of poly(vinylidend fluoride). Residual toner 5' on the carrier 1 is wiped out with the elastic body 93 of the roll 91, transferred to the magnet roll 94, and scraped off with a blade 97. Consequently, the carrier 1 and roll 91 contact each other more smoothly and damage to the surface of the carrier 1 is prevented, thereby prolonging its life.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention includes a step of developing an electrostatic latent image with a developer containing a -component magnetic toner, and a step of transferring the developed toner image onto a transfer sheet. Related to image forming methods. .

In the conventional electrophotographic copying system, for example, Se-sensation multiplier Z
An electrostatic latent image is formed on the surface of an image carrier such as an nO photoconductor or an organic photoconductor, and then the electrostatic latent image is developed using a magnetic toner, and the resulting developed toner image is transferred to a transfer sheet such as plain paper. A method has been proposed and put into practical use by transferring the image onto the image and then fixing it to obtain the final image.

In this so-called PPC method using magnetic toner, corona chargers and conductive rubber rollers are often used as transfer means, but no matter what transfer means is used,
It is not possible to obtain a transfer efficiency of 0.00%, and the normal transfer efficiency is around 90%.
(0% RH), the transfer efficiency is 60% or less.

Therefore, various cleaning methods have been proposed to remove the magnetic toner remaining on the surface of the image carrier after transfer.

Conventional cleaning methods include, for example, the fur brush cleaning method in which the surface of the image carrier is wiped by rotating a fur brush made of rabbit hair or synthetic fiber hair, and the fur brush cleaning method in which the surface of the image carrier is rubbed with a magnetic brush formed on a magnet roll. A scrubbing magnetic brush cleaning method is known.

In the fur brush cleaning method, the fur brush is heated at 1000 rpm to improve the cleaning effect.
Since the image carrier is rotated at high speeds such as p and m, there are problems such as premature fatigue of the image carrier surface and toner scattering. In addition, in the magnetic brush cleaning method, if the residual potential on the surface of the image carrier is high, an effect similar to that of a reproduced image may occur, resulting in poor cleaning. It is necessary to fine-tune the collected magnetic toner.
'Gune'''1'.-L is 6 removal 16') is difficult 1 etc. 0
There's a problem.

Other cleaning methods include, for example, No. 55-64274, No. 55115076, No. 57-
It has been proposed and put into practical use to use a cleaning roll whose at least the surface is made of a porous elastic layer, as described in each publication of No. 60364. This cleaning method has the advantage of high cleaning efficiency and extremely little toner scattering.

However, in this cleaning method, the cleaning means is in contact with the surface of the image carrier as in other methods, so although it is more advantageous than other methods, damage to the surface of the image carrier occurs and the life of the image carrier is reduced. (Printing durability of photoconductor)
There was a problem of shrinking the .

Problems to be Solved by the Invention It is an object of the present invention to provide an image forming method capable of solving the above-mentioned conventional problems and improving the printing durability of an image carrier.

Means for Solving the Problems In order to solve the above problems, the present invention forms an electrostatic latent image on the surface of an image carrier moving in a predetermined direction, and uses a developer containing magnetic toner particles to remove the electrostatic latent image. A process in which the image is developed, the obtained toner image is transferred onto a transfer sheet, and toner particles remaining on the surface of the image carrier after transfer are removed by a cleaning roll having at least a surface of a porous elastic layer. In the image forming method, at least the surface of the cleaning roll contains polyvinylidene fluoride powder.

Example Embodiments of the present invention will be described below based on the drawings.

Here, FIG. 1 is a schematic diagram showing an example of an electrophotographic apparatus including a transfer process.

In FIG. 1, 1 is a photoreceptor drum, 1a is a photoconductive layer formed on the surface of the photoreceptor drum 1, and the photoreceptor drum 1 is rotating in the direction of arrow Z.

2 is a corona charger, 3 is an optical system, 4 is a developing device,
After being uniformly charged by the corona charger 2, an electrostatic latent image (not shown) formed by exposure by the optical system 3 is transferred to the developing device 4.
A magnetic toner image 5 is obtained. 6 is a transfer sheet, 7 is a corona transfer device, and 8 is a fixing device. The transfer sheet 6 is superimposed on the obtained magnetic toner image 5, and a transfer electric field is applied from the back side by the corona transfer device 7 to form the magnetic toner image 5.
is transferred onto a transfer sheet 6, and then fixed by a fixing device M8 to obtain a hard copy.

The magnetic toner particles 5' remaining on the surface of the photosensitive drum 1 after the above transfer process are removed by a magnetic cleaning device 9. Note that 10 is a weight removing means such as a lamp for enhancing the cleaning effect, and is provided as necessary.

Here, FIG. 2 is a sectional view showing an example of a cleaning device in which the present invention is implemented in the electrophotographic apparatus of FIG. 1. In FIG. 2, 91 is a porous elastic roll;
It is formed by fixing a porous elastic layer 93 such as a sponge to the circumferential surface of a cylindrical shaft 92, and 11 is polyvinylidene fluoride powder contained at least on the surface of the porous elastic layer 93. . The surface of the porous elastic roll 91 is in contact with the photoconductive layer 1a on the surface of the photoreceptor drum 1, and the contact portion is in the direction of arrow A in the figure, that is,
It rotates in the opposite direction to the photosensitive drum 1.

A magnet roll 94 is arranged below the porous elastic roll 91 and in contact with it. The magnet roll 94 includes a sleeve 95 made of a non-magnetic material such as stainless steel or an aluminum alloy, and a permanent magnet member 96 having a plurality of magnetic poles on the surface inside the sleeve 95. 96 are configured to be able to rotate relative to each other. Further, an AC voltage source may be connected between the sleeve 95 and the conductive layer 1a of the photoreceptor drum 1. 97 is a scraper installed with one end close to or in contact with the sleeve 95;
On the other end side, a [-ner recovery container 98 is installed.

In addition, when the voltage source is connected to the sleeve 95, if the scraper 97 is in contact with the sleeve 1:, 95,
The scraper 97 needs to have at least an electrically insulating surface.

Since the magnetic cleaning device has the above-mentioned configuration, when the photosensitive drum 1 rotates and the magnetic toner particles 5' remaining on the drum 1 reach the contact portion with the porous elastic roll 91, the magnetic toner particles 5' are removed. , is removed from the surface of the photoreceptor drum 1 by the rotation of the porous elastic roll 91, transferred to the porous elastic roll 91, and then adsorbed onto the sleeve 95.

At this time, the rotation speed of the porous elastic roll 91 is set to 50 to 300 r, p, because if the rotation speed is too high, the magnetic toner and powder will easily scatter, and if it is too low, the effect of scraping off the magnetic toner will be weakened. It suffices to set it within a range of about m.

The magnetic toner particles 5' attracted onto the sleeve 95 as described above are conveyed in the direction of the arrow C in the figure by rotating the permanent magnet member 96 in the direction of the arrow B in the figure or in the opposite direction. , scraped off from the sleeve 95 by a scraper 97 and collected into a container 98. In this case, since polyvinylidene fluoride powder 11 exhibiting lubricating and non-adhesive properties is present on the surface of the elastic layer 93 that is in contact with the surface of the photoconductive layer 1a of the photosensitive drum 1, the elastic layer 93
The contact between the photoconductive layer 1a and the photoconductive layer 1a becomes smooth. Therefore, damage to the photoconductive layer 1a is significantly reduced, and the photosensitive drum 1
can significantly improve printing durability.

As polyvinylidene fluoride (CF2=CH2> powder, for example, Pennwald's 1N461°460.45
0,310 etc. A, Sono addition (A) C, Elastic roll 9
1 may be appropriately determined depending on the material dimensions, the number of rotations, and the amount of contact with the photoreceptor drum 1. Furthermore, various methods can be used to add the polyvinylidene fluoride powder 11 to the surface of the porous elastic roll 91, such as sprinkling the powder on the roll surface or pushing the powder onto the roll surface.

If the magnetic flux density on the sleeve 95 is 800 G or more, the magnetic toner particles 5' can be effectively removed. Further, the surface of the scraper 97 is roughened by a method such as blasting, knurling, or L, which is effective in preventing the magnetic toner from accumulating on the scraper 97.

Furthermore, the AC voltage applied between the sleeve 95 and the photosensitive drum 1 has a maximum voltage value of 0.3 to 2 kvr.

Good results can be obtained when p, s and the frequency is in the range of 100 to 2000H7.

FIG. 3 is a sectional view showing an example of a developing device in which the present invention is implemented in the electrophotographic apparatus shown in FIG.

In FIG. 3, reference numeral 41 denotes a toner container, in which magnetic toner particles 5', polyvinylidene fluoride powder 11, etc. are mixed and housed. 42 is a developing roll made of a non-magnetic (A material) such as stainless steel or aluminum alloy, and includes a sleeve 43 made of a non-magnetic material that rotates in the direction of arrow X in the figure, and a plurality of magnetic poles fixed inside the sleeve 43 on the surface. 45.
is a doctor blade whose one end is installed close to the sleeve 43.

The magnetic particles 5' are attracted onto the sleeve 43 by the magnetic attraction force of the permanent magnet member 44, and when they pass through the doctor gap d of the doctor blade 45 by rotation of the sleeve 43 in the arrow After the developing gill 1 is regulated, it comes into contact with the photoconductive layer 1a on the surface of the photosensitive drum 1 near the tube D of the developing gill 1 to develop an electrostatic latent image, and is then stored in the toner container 41.

In this case, polyvinylidene fluoride powder 11 is added to the developer.
, the damage to the photoconductive layer 1a on the surface of the photoreceptor drum 1 is reduced, which is extremely effective in improving the printing durability of the photoreceptor drum 1.

Specific example 1 In FIGS. 1 and 2, the photoreceptor drum 1 has an outer diameter of 2
A selenium drum with a diameter of 10 mm was used at a circumferential speed of 150
Rotated at mm/sea. The surface of this selenium drum was uniformly charged to +750V and then exposed to form an electrostatic latent image.
Then, the volume resistivity at C4,0OOV/cm is 1
Magnetic brush development was performed using 0 μΩ・cm magnetic toner [average particle size 15 μm, magnetic powder (Toda Kogyo Seisaku T500) content 60 wt%], and plain paper (volume resistance 101′Ω・cm) was used as a transfer sheet. 5 kV corona transfer was performed. The transfer efficiency in this case was 92%. however,
The temperature was 20° C. and the humidity was 60% R,H.

In the cleaning device 9, polyfluorinated
The outer diameter of the porous elastic roll 91 coated with 301 F (manufactured by Pennwald Co., Ltd.) was 35 mm, and the number of revolutions was 80 r, l). Further, as the magnet roll 94, a stainless steel sleeve 95 with an outer diameter of 32 mm is used, and the permanent magnet member 96 has an outer diameter of 29 mm.
mφ 3a-Ferai 1-! ! An 8-pole symmetrical magnet was applied to the stone, and the magnetic flux density on the sleeve 95 was set to 850G. Then, the permanent magnet member 96 is fixed, and the sleeve 95 is
, l11. Rotated at m and performed C continuous machining. As a result, the life of the photoreceptor drum 1 is significantly improved (printing durability 120,000 sheets) compared to cleaning using a porous elastic roll that does not contain polyvinylidene fluoride (printing durability 2,000 sheets). I was able to do that.

Specific Example 2 In FIG. 3, magnetic toner 5' was used as a developer at 150
(Results obtained by creating an image under the same conditions as in Example 1 above, except that a mixture of Pennwald's 460 with a particle size of 2 μm or less and Shimono 159 was used as polyvinylidene fluoride 11. In this case, the outer diameter of the sleeve 43 of the developing roll 42 was 32 mmφ, and the outer diameter of the permanent magnet member 44 was 29 mm.
mφ, the magnetic force on the sleeve 43 is 600G, the doctor gap d is 0.4 mm, the developing gap D is Q, 3n.
u+.

The rotation speed of the sleeve 43 was set to 20Qr, p9m.

Effects of the Invention As described above, according to the present invention, the printing durability of an image carrier can be improved.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an example of an electrophotographic apparatus including a transfer process, FIG. 2 is a sectional view showing an example of a cleaning device in which the present invention is applied to the electrophotographic apparatus of FIG. 1, and FIG. ,
FIG. 2 is a sectional view showing an example of a developing device in which the present invention is implemented in the same electrophotographic apparatus. DESCRIPTION OF SYMBOLS 1... Photosensitive drum, 4... Developing device, 5... Magnetic toner image, 5'... Magnetic toner particles, 6... Transfer sheet, 9... Magnetic cleaning device, 11...・Polyfluorinated vinyl powder, 42...Developing roll, 91
...Elastic roll. Patent applicant Hitachi Metals Co., Ltd. Figure 3 41 725-

Claims (1)

[Claims] (1) forming an electrostatic latent image on the surface of an image carrier moving in a predetermined direction, developing the electrostatic latent image with a developer containing magnetic toner particles, and transferring the obtained toner image onto a transfer sheet;
An image forming method including a process of removing toner particles remaining on the surface of the image carrier after transfer using a cleaning roll having at least a surface of a porous elastic layer,
An image forming method characterized in that at least the surface of the cleaning roll contains polynylidene fluoride powder. <2) The image forming method according to claim 1, wherein the developer comprises polyvinylidene fluoride powder and a magnetic toner.