JPH01239568A - Image forming method - Google Patents

Abstract

PURPOSE:To improve recording quality by making a magnet roller fixed and rotating a sleeve on the outside of said roller so that developer is carried. CONSTITUTION:A magnetic brush developing machine 9 is constituted by incorporating the magnet roller 9a in the sleeve 9b. The magnet roller 9a is made fixed and the developer 4 is carried by rotating the sleeve 9b. Since the sleeve 9b is rotated and the magnet roller 9a is fixed, magnetic flux in a developing part becomes constant and the change of the density of the bristles of the developer does not occur. Therefore, the variation of a rectangular wave voltage which is hitherto generated by the rotation of the magnet roller 9a becomes small and a distinct toner image 8 without a developed stripe can be obtained. Thus, the recording quality can be improved.

Description

[Detailed Description of the Invention] [Summary] A toner image is formed on a portion of a photoreceptor that is irradiated with image light,
The purpose of this invention is to improve the effect of applying a rectangular wave voltage and improve the recording quality in an image forming method that applies a rectangular wave voltage to the sleeve of a developing machine. a photoconductor comprising at least a transparent substrate, a transparent or translucent conductive layer, and a photoconductive layer; a conductive nonmagnetic sleeve disposed on the photoconductive layer side of the photoconductor; and a magnet roller therein. a magnetic brush developing device in which the outside of the sleeve is filled with conductive developer; voltage applying means for generating and applying a rectangular wave voltage to the sleeve of the magnetic brush developing device; and an image exposure means provided on the conductive layer side at a position facing the sleeve of the magnetic brush developing device to perform image exposure, wherein the magnet roller is fixed and the outer sleeve is rotated. A method of transporting the developer is adopted.

[Industrial Field of Application] The present invention relates to an image forming method in which a toner image is formed on a portion of a photoreceptor irradiated with image light, and the toner image is transferred to display or recording paper.

Current copying machines and high-speed, high-printing quality printers generally use an electrophotographic recording method. This method is a so-called Carlson process in which a photoreceptor is used as a recording medium and recording is performed through the steps of -like charging, image exposure, development, transfer, fixing, neutralization, and cleaning.

In the Carlson process, a corona discharger is used for -like charging, transfer, and static elimination. Since the corona discharger is configured to apply a high voltage of several kV to the corona wire, it requires a high-voltage power source and is easily affected by humidity, dust, etc., so it has the disadvantage of low reliability. Furthermore, ozone generated by corona dischargers produces odor, and in recent years, the toxicity of ozone to the human body has become a problem.

Furthermore, since the above-mentioned seven steps are required, there is a drawback that the apparatus becomes complicated and large.

Recently, in view of the above problems, we have eliminated the need for a corona discharger,
Image forming methods have been proposed that focus on miniaturizing devices. The present invention relates to one such method.

[Conventional technology]

FIG. 6 shows a schematic side view of a conventional image forming apparatus. In the figure, a photoreceptor 1 is composed of a transparent substrate 1a, a transparent conductive layer 1b, and a photoconductive layer 1c, and the transparent conductive layer 1b is connected to ground. The magnetic brush developing device 2 provided on the photoconductive layer 1c side of the photoreceptor 1 is composed of a magnet roller 2a and a conductive non-magnetic sleeve 2b, and the magnet roller 2a is freely rotatable. This developing device 2 is filled with a developer 4 made of a mixture of charged toner (the polarity is negative in the figure) and a conductive carrier, or a developer 4 made of conductive toner. The developer 4 is transported to. Image exposure means 5 is arranged on the opposite side of the magnetic brush developing device 2 with the photoreceptor 1 in between.

A rectangular wave voltage is applied to the magnetic brush developing device 2 by a power source 3. This rectangular wave voltage is synchronized with the light emission timing of the image exposure means 5 by the control system 6. This situation is shown in FIG. Voltage V.

When is being applied, the image exposure means 5 performs image exposure. This voltage {circle around (2)} has a polarity opposite to the photocarrier polarity of the photoreceptor 1 used (in the figure, it is negative because the carrier is positive). In addition, ``■'' is the ground potential or the opposite polarity of ``8''.

Next, the image forming process in this device will be described. When the photoconductive layer IC of the photoreceptor 1 is imagewise exposed, photocarriers are generated in the photoconductive layer 1c. At this time, the control system 6
Since the rectangular wave voltage Vl (minus) is applied to the sleeve 2b in synchronization with the light emission timing of the image exposure means 5, carriers (holes) of the opposite polarity to V8 among the photocarriers are transferred to the surface of the photoconductive layer IC. The latent image charge 7 becomes the latent image charge 7.

At this time, since the capacitance of the photoconductive layer 1c apparently increases, the amount of adhered toner increases, resulting in a toner image with a certain degree of contrast between exposed and non-exposed areas.

At the next instant, V is applied to the sleeve 2b.

This V serves to collect excess toner in the non-exposed area that adheres to the photoreceptor 1 during application to the developing device 2 using electrostatic force. At this time, a small amount of toner in the exposed area is also collected, but due to the electrostatic binding force of the latent image charge 7 and the toner charge, most of the toner remains on the photoreceptor 1, forming a clear toner image 8. .

[Problem to be solved by the invention]

By the way, in the conventional device, the developer 4 is conveyed by rotating the magnet roller 2a. The conveyance of the developer by the rotation of the magnet roller causes changes in the density of the spikes of the developer in the developing section where the developer 4 is in contact with the photoreceptor 1 . That is, as the magnet roller 2a rotates, the magnetic flux changes periodically in the developing section, so that the density of the spikes of developer changes. This change in density changes the effective electrical resistance of the developer in the developing section, and as a result, the rectangular wave voltage applied to the sleeve fluctuates on the photoreceptor 1, and the function of the rectangular wave voltage described above changes. I can't perform to my full potential. As a result, development stripes, fog, etc. occur, and good prints are often not obtained.

Furthermore, between the magnetic roller and the magnetic pole, the ears of the developer 4 are lying down as shown in the figure, so the developing machine 2 and the photoreceptor 1
The substantial electrical resistance between them increases.

The rectangular wave voltage applied to the sleeve is affected by a time constant determined by the electrical resistance of the developer and the capacitance of the developer and the photoreceptor l, so that only a distorted voltage waveform is applied to the photoreceptor l.
Due to this reason as well, the function of the rectangular wave voltage is insufficient and fogging is likely to occur.

Furthermore, in the development area, since the direction of conveyance of the developer 4 and the direction of movement of the photoreceptor 1 are the same, the ability to supply the developer 4 to the electrostatic latent image 7 is low, and there is a risk that the print density will be low. be.

The technical problem of the present invention is to improve the effect of applying the rectangular wave voltage in an image forming method in which a rectangular wave voltage is applied to the sleeve of a developing machine, and to enable sufficient supply of developer to the developing area. The goal is to improve quality.

[Means to solve the problem]

FIG. 1 is a diagram illustrating the basic principle of the image forming method according to the present invention. Note that the control system is omitted in the figure.

The magnetic brush developing device 9 has a structure in which a magnet roller 9a is built into a sleeve 9b. In the present invention,
The developer 4 is conveyed by keeping the magnetic roller 9a fixed and rotating the sleeve 9b.

[Effect]

Since the sleeve 9b is rotated in this way and the magnet roller 9a is fixed, the magnetic flux in the developing section is constant.
There is no change in the density of the ears of the developer. Therefore, fluctuations in the rectangular wave voltage that conventionally occur due to rotation of the magnet roller 9a are reduced, and a clear toner image 8 without development stripes is obtained.

Also, one of the magnetic poles 9 of the fixed magnet roller 9a
By arranging the developer 4 facing the photoreceptor 1, the developer 4 always has spikes. Therefore, the effective electrical resistance of the developer between the developing device 9 and the photoreceptor 1 is smaller than in the conventional method. As a result, the time constant in the developing area is also reduced, and the rectangular wave voltage applied to the sleeve 9b is applied to the photoreceptor 1 with less distortion, resulting in a clear toner image 8 with less fog.

In the development area, the moving direction of the photoreceptor 1 and the moving direction of the developer 4 are opposite to each other. As a result, the developer 4 is sufficiently supplied to the electrostatic latent image 7 in the development area, so that the printing density of the toner image 8 becomes high.

〔Example〕

Next, examples will be used to explain how the image forming method according to the present invention is actually implemented. FIG. 2 shows the entire outline of a first embodiment in which the method of the present invention is applied to an image recording apparatus.

10 is an endless photoreceptor film. As shown in FIG. 3, this photoreceptor film 10 is placed on a transparent substrate lod of polyethylene terephthalate with a thickness of 100 μm.
A transparent conductive layer 10b made of an O (indium oxide) vapor deposited film is provided, and a CGL (charge generation layer) 10c is further provided as a photoconductive layer.
and CTL (charge transport layer) lod, with a thickness of approximately 1
A functionally separated organic photoconductive layer with a thickness of 0 μm is provided. Transparent conductive layer 10b of photoreceptor film 10 as described above
is connected to ground, and the photoreceptor film 10 itself is conveyed in the direction of the arrow in the figure by a power system (not shown) connected to the film drive roller 11.

Reference numeral 12 denotes a magnetic brush developing machine, in which a sleeve 12b is freely rotatable, and a magnet roller 12a is provided inside the sleeve 12b. One of the magnetic poles 121 of the magnet roller 12a is
It is arranged opposite to the photoreceptor film 10, and this portion is imagewise exposed. A magnetic brush developing device 12 is filled with a developer 14, which is a mixture of a conductive carrier and a negatively charged insulating toner, and is conveyed in the direction of the arrow in the figure by rotation of the sleeve 12b. In this case, in the developing section, the direction in which the developer 14 is conveyed and the direction in which the photoreceptor film 10 is moved are opposite to each other. 15 is a doctor blade for regulating the height of the developer 14;

13 is a power source that generates a rectangular wave voltage. Kome power supply 13
A rectangular wave voltage emitted from the sleeve 12b is applied to the sleeve 12b. The rectangular wave voltage and the timing of image exposure, which will be described later, are synchronized by a control system (not shown). This situation is shown in FIG. Since the photoconductive Jt'N10c and 10d of this example used a hole transfer type, the voltage at the time of forming an electrostatic latent image with a rectangular wave voltage was a negative voltage, and ranged from -200V to -70V.
It was set to 0V. Further, the voltage during fog recovery of the rectangular wave voltage was a positive voltage, and was set to 0 to +100V. As shown in the figure, the timing of the rectangular wave voltage and the image exposure is such that, taking into consideration the mobility of the photoreceptor film 10, image exposure is performed after applying a negative voltage, and after the completion of exposure, a positive voltage is applied after a period of time. ing.

A magnetic brush developing device 12 is installed with the photosensitive film 10 sandwiched therebetween.
An image exposure means is arranged at a position facing the.

This image exposure means is an LED array optical system 16, which uses an LED array 16a as an exposure light source and a SELFOC lens array 16b as a condensing lens. A holding plate 16c made of glass is used. In this embodiment, in addition to the LED array optical system mentioned as the image exposure means, an optical system using a liquid crystal shutter, an optical system using electroluminescence, an optical system using a laser, etc. can also be applied. .

17 is a toner image formed on the photoreceptor film 10. 18 is recording paper. 19 is a conductive rubber roller for transfer, and the voltage (-200V~=600V) is applied by the power supply 20.
V) is applied. A toner image 21 is electrostatically transferred onto the recording paper 18, and is fixed on the recording paper 18 by a heat roller fixing device 22 to become a semi-permanent recorded image 23.

24 is a residual toner image remaining on the photoreceptor film 10 after transfer. Reference numeral 25 denotes a static eliminating light source that removes charges on the residual toner image 24 and latent image charges in the photoconductive layers 10c and 10d. 26 is a toner image that has been neutralized and has lost its electrostatic binding force.

Next, the image recording process in this embodiment will be explained.

The photoreceptor film 10 is conveyed in the direction of the arrow, and the developing machine 12
The sleeve 12a is rotated to convey the developer 14 in the direction of the arrow, and the power source 13 applies a rectangular wave voltage to the sleeve 12a. In this state, the LED array optical system 16 exposes the photoreceptor film 10 to an image.

Then, photocarriers are generated at CGLloc. At this time, since a negative square wave voltage is applied in synchronization with the light emission timing of the LED array 16a, the holes in the photocarrier move within the CTL 10d near the surface of the photoreceptor and become latent image charges.

Therefore, in the image-exposed areas, the capacitance of the photoconductive layers 10C and 10d appears to increase, and the amount of toner adhering to the surface of the photoreceptor film 10 increases, causing a difference between exposed areas and non-exposed areas. This results in a toner image with some degree of contrast.

At the next moment, the positive voltage of the square wave voltage is applied to the sleeve 1.
2b. This positive voltage acts, and excess toner in the non-exposed areas that adheres to the photoreceptor film 10 when the negative voltage is applied is collected by the developing device 12 by electrostatic force. At this time, a small amount of toner in the exposed area is also collected, but most of the toner remains on the photoreceptor film 10 due to the electrostatic binding force of the latent image charge and the toner charge, and a toner image 17 is formed.

Next, toner image 17 is electrostatically transferred onto recording paper 18 using transfer roller 19 . The transferred toner image 21 is fixed on the recording paper 18 by a fixing device 22, and a semi-permanent recorded image 23 is obtained.

On the other hand, the residual toner image 24 remaining on the photoreceptor film 10 after the transfer is neutralized using a neutralizing light source 25 .

The toner image 26 from which the charge has been removed is collected by scraping off the developer 14 and electrostatic force caused by the voltage applied to the sleeve 12b, and is reused. The next image formation is residual toner image 2.
6 will be collected at the same time. In this way, residual toner image 2
6 and the next image formation at the same time, the image exposure means 16 and the developing machine 12 are used with the photoreceptor film 10 in between.
Since they are located opposite each other, there is no problem.

According to this embodiment, ozone that is harmful to the human body is generated, and several kilograms of ozone are generated.
A corona discharger, which requires a high voltage of V, is not used. In addition, since it is a simple recording process with a smaller number of errors than the Carlson process, it is possible to downsize the apparatus.

Moreover, the magnetic roller 12 of the magnetic brush developing machine 12
a is fixed, and the developer 1 is released by rotating the sleeve 12b.
4, there is no change in the density of the spikes of the developer 14, and fluctuations in the rectangular wave voltage on the photoreceptor film 10 are reduced. As a result, a recorded image 23 without a developing section was obtained.

Further, by arranging the magnetic pole 121 of the fixed magnet roller 12a and the photoreceptor film 10 to face each other, the developer 1
4 is in a state where the spikes are always standing up, and the effective electrical resistance of the developer between the developing device 12 and the photoreceptor film 10 becomes small. Therefore, the time constant in the development area is also reduced, and the rectangular wave voltage applied to the sleeve 12b is in a state with less distortion, so that a clear recorded image 23 with less fogging is obtained.

By setting the moving direction of the photoreceptor film 10 and the moving direction of the developer 14 in opposite directions in the developing area, the developer 14 is sufficiently supplied to the electrostatic latent image in the developing area, so that the recorded image The print density of No. 23 was high.

FIG. 5 shows the entire structure of a second embodiment in which the present invention is applied to an image recording apparatus.

This embodiment differs from the first embodiment in that a photoconductor drum 27 is used instead of the photoconductor film 10, and after forming a toner image 32 on the photoconductor drum 27 using a rectangular wave voltage, Furthermore, a magnetic brush developing device 33 is provided as fog recovery means.

Next, the configuration and operation of this embodiment device will be explained.

Reference numeral 27 denotes a photoreceptor drum, which has almost the same layer structure as the photoreceptor film IO described above. However, the thickness of the transparent substrate is 5
mm glass is used, and a transparent conductive layer (ITO) is placed on top of it.
・It is equipped with a functionally separated organic photoconductive layer.

The transparent conductive layer of the photoreceptor drum 27 as described above is connected to ground, and the photoreceptor drum 27 itself rotates in the direction of the arrow (counterclockwise) in the figure.

A first magnetic brush developing device 28 and an LED array optical system 31 as image exposure means are sandwiched between the photosensitive drum 27.
are placed facing each other. As in the first embodiment, the first magnetic brush developing device 28 transports a developer 30, which is a mixture of a conductive carrier and an insulating toner, by rotating the sleeve. A magnetic roller is provided.

One of the magnetic poles 281 of the magnet roller is arranged to face the developing section of the photosensitive drum 27, and the partial LED array optical system 31 exposes an image.

The power source 29 applies a rectangular wave voltage to the sleeve in synchronization with the image exposure timing, almost similarly to the first embodiment. In this toner image forming section, a toner image 3 is formed on the photoreceptor drum 27 based on the principle shown in the first embodiment.
2 is formed.

In the toner image 32, there are cases where the fog recovery effect of the rectangular wave voltage is insufficient, and fog may occur.

In the second embodiment, a second magnetic brush developing device 33 is arranged to recover the fog on the toner image 32 again.

This developing device 33 is filled with the same developer 34 as the developer 30 of the first developing device 28, and the developer 34 is conveyed by rotation of a sleeve or a magnet roller. moreover,
A toner recovery voltage is applied to the sleeve by a power source 35 that generates a voltage of the same polarity as the photocarriers in the photoconductive layer.

The fog on the toner image 32 on the photosensitive drum 27 is electrostatically collected by the developing device 33 by the scraping effect of the developer 34 and the toner collection voltage applied to the sleeve. At this time, a small amount of toner in the image area is also collected. However, due to the electrostatic latent image formed by the first developing device 28 and the electrostatic binding force of the toner charge, most of the toner is transferred to the photoreceptor drum 28.
It remains on top, forming a clear toner image 36.

Next, the toner image 36 is electrostatically transferred onto a recording paper 37 using a transfer roller 38 to which a transfer voltage 39 is applied. The transferred toner image 40 is transferred to a recording paper 37 by a fixing device 41.
A semi-permanent recorded image 42 is obtained.

On the other hand, the residual toner image 43 remaining on the light emitting drum 27 after the transfer is neutralized using the static eliminating light B44. The neutralized toner image 45 is collected by scraping by the first magnetic brush developing device 28 and electrostatic force caused by the voltage applied to the sleeve, and is reused.

According to this embodiment, in addition to the effects of the first embodiment, since a second magnetic brush developing machine is provided as a fog recovery process,
A clearer and better recorded image than in the first example was obtained.

Furthermore, when using a photoreceptor film as in the first embodiment, the connecting portions at the beginning and end of the photoreceptor film become printing prohibited areas, so it was necessary to control the device to avoid printing there. However, when a photosensitive drum is used as in this embodiment, there is no print-prohibited area, and therefore no special device control is required.

In the above two embodiments, the photoreceptor materials include organic materials such as phthalocyanine materials, PVK-TNF, azo dyes, and thiapyrylium dyes, and inorganic materials such as selenium-based photoreceptors, a-5i-CdS, zinc oxide, etc. It is possible to use

Further, as an image recording process, in the above embodiment, the residual toner remaining on the photoreceptor after transfer was collected by a magnetic brush developing machine, but a recording process in which the residual toner is removed by a fur brush cleaner, a blade cleaner, etc. may also be used. .

In the transfer process, a roller transfer method was used in the example, but the same effects as in the above example can be obtained even if a corona transfer method is used.

Further, the present invention can be applied not only to an image recording apparatus as in the above-mentioned embodiments, but also to a display apparatus in which a toner image on a photoreceptor is directly viewed without providing a transfer step, to obtain sufficient effects.

〔Effect of the invention〕

As described above, according to the present invention, there is no need for a corona discharger that generates ozone that is harmful to the human body and requires a high voltage of several kV. In addition, since it is a simple recording process with fewer numbers than the Carlson process, the apparatus can be made smaller.

Furthermore, the magnetic roller of the magnetic brush developing machine is fixed, its magnetic pole and the image exposure position of the photoconductor are arranged opposite each other, and the developer is conveyed by rotation of the sleeve, and the direction of conveyance is also opposite to the direction of movement of the photoconductor. By doing so, the effective electrical resistance of the developer in the development area can be reduced. Therefore, the rectangular wave voltage applied to the sleeve can sufficiently exhibit an image forming effect, so that a clear and good toner image can be formed on the photoreceptor.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view explaining the basic principle of the image forming method according to the present invention, FIGS. 2 to 4 are diagrams showing a first embodiment of the present invention, and FIG. 5 is a second embodiment of the present invention. FIG. 6 is a schematic sectional view of a conventional image forming apparatus, and FIG. 7 is a waveform diagram showing recording voltage application timing. In the figure, 1 is a photoreceptor, 1a is a transparent substrate, 1b is a transparent conductive layer, 1c is a photoconductive layer, 4, 14, 30, 34 is a developer, 5 is an image exposure means, 9 is a developing machine, and 9a is a magnet roller. , 9b is a sleeve, and 91.121.281 is a magnetic pole located opposite the image exposure means. Patent Applicant Fujitsu Limited Sub-Agent Yasushi Fukushima Patent Attorney Yasushi Fukushima Drawing 1 Controversy 3: (No refutation of self-answer) Water-receiving surface of the moon Figure 1 First major embodiment of the present invention 2 Diagram n, 1987, July 27, 1983. Director General of the Japan Patent Office Yoshi 1) Takeshi Moon 1, Indication of the case: Japanese Patent Application No. 63-669822, Title of the invention: Image forming method 3, Representative of the person making the amendment: Takashi Yamamoto 4, Agent

Claims (1)

[Claims] 1. A photoreceptor (1) comprising at least a transparent substrate (1a), a transparent or translucent conductive layer (1b), and a photoconductive layer (1c); and the photoreceptor (1). ) consists of a conductive non-magnetic sleeve (9b) disposed on the photoconductive layer (1c) side and a magnet roller (9a) therein, and a conductive developer (4).
A magnetic brush developer (
9), a voltage applying means (3) for generating and applying a rectangular wave voltage to the sleeve (9b) of the magnetic brush developing machine (9), and on the conductive layer (1b) side of the photoreceptor (1), In the image forming apparatus, the image forming apparatus includes an image exposure means (5) that is provided at a position facing the sleeve (9b) of the magnetic brush developing machine (9) and performs image exposure, wherein the magnet roller (9a) is fixed. , an image forming method characterized in that the developer (4) is transported by rotating the outer sleeve (9b). 2. The image forming method according to claim 1, wherein in the developing section, the direction of conveyance of the developer (4) and the direction of movement of the photoreceptor (1) are opposite to each other. 3. The image forming method according to claim 1, wherein one magnetic pole (91) of the magnet roller (9a) is arranged at a position facing the photoreceptor (1).