JPS62220968A - Image forming method - Google Patents

Abstract

PURPOSE:To form a fog-free image by one stage of a developing machine by providing a pulse voltage applying means which applies a pulse voltage to a sleeve which constituted a developing means. CONSTITUTION:The pulse voltage applying means 7 applies the sleeve 2a with the pulse voltage which is set to the 1st voltage value 7a as a minus voltage value for moving negatively charged toner 6 from the developing machine 2 onto a photosensitive body 1 and sticking the toner and the 2nd voltage value 7b that is 0V or a plus voltage value of recovering the toner 6 sticking on the photosensitive body 1 to the developing machine 2. Consequently, the toner is stuck and recovered simultaneously with image exposure and toner sticking on an unexposed part which is a background part can be recovered, so the fog-free toner image 3 is obtained when the photosensitive body 1 leaves a development area.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an image forming method in which an exposing means and a developing means are installed facing each other with a photoreceptor interposed therebetween, and a toner image is formed simultaneously with image exposure. A pulsed voltage applying means is provided to apply a pulsed voltage to the sleeve to be processed, and a pulsed voltage is applied to the sleeve during image exposure to form an image and perform contrast development in another period, thereby eliminating fog using a single developing machine. It is designed to form an image that does not require an image.

[Industrial application field]

The present invention relates to an image forming method in which a toner image is formed on a photoreceptor at the same time as image exposure and is displayed or transferred.

Currently, optical printers and copying machines generally perform recording using electrophotography, and perform recording through processes such as charging, exposure, development, and transfer.

The charging process uses a corotron that performs charging by corona discharge, which requires high voltage and also generates harmful ozone.

Therefore, there is a need for an image forming method that does not generate harmful ozone and can form images at low voltage.

FIG. 4 is a diagram for explaining an image forming method that does not use a corona charger, which does not generate ozone and can form images at low voltage.

In this image forming method, as shown in FIG. 4, a transparent conductive layer 112 made of ITO or the like is provided on a transparent substrate 111, and a photoreceptor 113 made of CdS or the like having a thickness of 65 μm is provided thereon. Furthermore, a conductive magnetic toner developing device 116 is disposed opposite to a recording film 115 provided with a white insulating layer 114 having a resistance value of a certain degree.
While applying a voltage between the transparent conductive layer 112 and the transparent conductive layer 112,
8. Image exposure is performed from the transparent substrate 111 side using an fθ resin 119 or the like.

Through this image exposure, a voltage is applied between the developing device 116 and the transparent conductive layer 112 of the recording film 115, and then the photoreceptor layer 1130 is irradiated with light and has a reduced resistance value.
Toner is electrostatically deposited in the area. On the other hand, since the thickness of the insulating layer 114 is sufficiently large in the area that is not irradiated with light, the electrostatic adhesion force between it and the toner is weak9. This will prevent toner from adhering. Therefore, a toner image 120 corresponding to image exposure is formed.

After image formation, the charges induced by light irradiation and the charges induced in the toner are discharged through the surface layer within one cycle of image display, and are magnetically attracted and collected in the developing device 116 during the next image formation. be done. In this case, since the image exposure is performed from the transparent substrate 111 side of the recording film 115, toner recovery, image exposure, and development can be performed simultaneously.

Such an image forming method is described in Japanese Patent Application Laid-Open No. 1ifl 57-11.
This method is known from Japanese Patent No. 9375.

However, the conventional image forming method shown in FIG. 4 has the advantage of not using a corona discharger, but it forms an image by utilizing the difference in Coulomb force acting on the toner between exposed and non-exposed areas. Since the photoreceptor layer 113
must be made thicker. However, the thick photoreceptor layer 11
3k It is difficult to form a uniform thickness. Also,
Increasing the thickness of the photoreceptor layer has the drawback of increasing the amount of material used and increasing costs. Furthermore, photoreceptor 1i
As Ii 113 becomes thicker, it is necessary to increase the voltage applied between the transparent conductive film 112 of the recording film 115 and the developing device 116, and there is a drawback that the photosensitivity decreases.

[Conventional technology]

Therefore, a new image forming method has been proposed which improves all of the above-mentioned conventional drawbacks and is capable of forming images even on thin photoreceptors at low voltage and with high sensitivity without using a corona discharger. .

There are two possible image forming methods as shown in FIGS. 5 and 6 depending on the mobility of the photoreceptor used. Figure 5 shows a method that can be applied to photoreceptors with slow mobility, such as non-polluting and inexpensive organic photoreceptors, and Figure 6 shows a method that can be applied to photoreceptors with relatively fast mobility, such as high-speed type organic photoreceptors. This method can be applied to photoreceptors, Se photoreceptors, CdS photoreceptors, and the like.

First, an outline of the proposed principle shown in FIG. 5 will be explained.

The photoreceptor 124 is made up of a transparent substrate 121, a transparent conductive layer 122, and a photoconductive layer 123, which are laminated in this order, and has a structure in which a non-magnetic sleeve is provided on the surface of a transparent magnet roller, and conductive magnetic toner or This is a so-called magnetic brush developing machine, in which a two-component developer containing a carrier made of conductive iron powder and an insulating toner is mixed. A developing bias voltage is applied by a power source 126. Reference numeral 127 is a uniform single layer formed in the shape of a photoreceptor. 128 is an image exposure means, specifically an LED array optical system consisting of a cell-hoc lens and an LED array. 129 is a photocarrier near the surface of the photoreceptor layer, which becomes a latent image charge. 130 is toner in the exposed area. 131 is a second unit for collecting toner in the non-exposure ft area;
The developing (contrast developing) means is, specifically, an abrasive brush developing machine similar to that used for forming a single layer of uniform flatness. A voltage having a polarity opposite to the developing bias voltage of the first developing device is applied to the second developing device by a power source 132. 133 is a toner image from which toner in non-exposed areas has been removed.

Next, the image type 77W procedure will be described.

In FIG. 5, by applying a developing bias to the developing device 125 and conveying the toner, uniform flat toner is completely formed on the optical surface of the photoreceptor.

Image exposure device fi! is applied from the transparent substrate side of the photoreceptor 124! 12
Image exposure is performed at step 8. In the exposure section, light guide 1! Among the photocarriers generated in the layer, carriers having a polarity opposite to that of the solid toner layer 127 move toward the surface and become a latent image charge.

Next, the developing machine 131 connected to the reverse bias voltage
The toner 131 in the non-exposed area is transported to the developing device 131 by electrostatic force. At this time, the toner 130 in the image area is also slightly collected, but the latent image charge 129
Due to the electrostatic binding force between the toner charge and the toner charge, most of the toner remains on the photoreceptor, and a toner image is formed.

This toner image is transferred to a conventional transfer means 135, if necessary.
After being transferred onto a recording paper 136 by a photoreceptor, the electric charge generated on the photoreceptor is removed by a seven-light static eliminator 137 or the like, and collected into a first developing device.

At the same time as this residual toner is collected, the next image formation is performed. Continuous recording is performed by repeating the above process.

Next, an outline of the second proposed principle shown in FIG. 6 will be explained.

The difference between FIG. 6 and FIG. 5 is that an image exposure and development process is employed in which petatoner development and image exposure are performed simultaneously. For this reason, during image exposure and development, the capacity of the photoreceptor increases apparently in the exposed area, so the amount of toner adhering to the exposed area increases, and there is a certain degree of contrast between the exposed area and the non-exposed area. However, in the image forming methods shown in Figures 5 and 6 above, it is necessary to perform two types of development, solid toner development and contrast development, and the configuration of the developing machine is complicated. Therefore, even if the image forming method of the present invention adopts the above-mentioned process and does not use a corona discharger, the present invention has the drawback that two types of solid toner development and contrast development are required during image formation.
To provide an image forming method capable of performing fog-free development with one developing machine without performing two developing processes, thereby simplifying the configuration of the developing machine.

[Means to solve all problems]

The first diagram in the south is a diagram for explaining the entire principle of the image forming method according to the present invention.

In the figure, 1 is a photoreceptor and a transparent substrate la.

A transparent or translucent conductive layer 1b connected to ground.

The photoconductive layer 1c is sequentially laminated, and 2 is a developing machine, which includes a conductive non-magnetic sleeve 2a and a magnet row 22.
b, and positive or negative (negative in Figure 1) toward the photoreceptor 1 direction.
5 is an image exposure means which performs image exposure by irradiating light corresponding to recorded information from the transparent substrate 1a side onto the photoreceptor 1; 7 is a means for applying a pulse voltage; The negatively charged toner 6 is transferred to the developing machine 2.
A first voltage value 7a, which is a negative voltage value, is used to move the toner onto the photoreceptor 1 from the side and deposit it on the photoreceptor 1, and a first voltage value 7a, which is a negative voltage value, is used to transfer the toner 6' adhering to the photoreceptor 1 to the developing machine 2 side. A second voltage value 7 that is near zero V or a positive voltage value
A pulse-like voltage (referred to as a recording pulse) set at .b and .b is applied to the sleeve 2a.

Further, the pulse voltage applying means 7 is configured to apply a first voltage value 7a onto the sleeve 2a during image exposure by the image exposure means 5, and to normally apply a second voltage value 7bQ onto the sleeve 2a. There is.

[Effect]

In the configuration described above, image formation is performed as follows.

First, when forming a non-toner image, a second
A voltage value 7b is applied to prevent the toner 6 from adhering to the non-toner image forming area.0 When forming a toner image, a voltage value 7b is applied on the sleeve 2a simultaneously with the image exposure by the image exposure means 5. 1 voltage value 7a
By applying , Sittoner-6 is deposited on the photoreceptor 1.

That is, by applying this first voltage value 7a, the photoreceptor l
Toner adheres to both the upper exposed and non-exposed areas. but,
In the exposure section, photocarriers are generated in the photoconductive layer 1c by image exposure, and among the photocarriers, a first voltage value 7 is generated.
Since the carrier (+) with the opposite polarity to a moves to the vicinity of the surface of the photoconductive layer 1c and becomes a latent image charge 8, the photoreceptor container apparently increases due to the latent image charge 8, so the amount of adhered toner increases. There will be more.

Next, the recording pulse is turned OFF, that is, it becomes the second voltage value 7b, and the sleeve 2a is kept at zero or at a potential opposite to that of the recording pulse. By applying the first voltage value 7& to the sleeve 2a, the toner adhering to the exposed and non-exposed areas of the photoreceptor 1 is collected by the developing device 2. However, at this time, most of the toner remains on the photoreceptor 1 in the exposed area due to the electrostatic binding force between the latent image charge 8 formed in the photoconductive layer 1c and the toner charge.

Further, as the photoreceptor 1 moves, a recording pulse is applied simultaneously with image exposure for the next new recording, and the toner is deposited on the photoreceptor 1 and collected twice as described above. .

In this way, by applying the recording pulse, one collection of toner adhesion is performed at the same time as image exposure, and the toner adhering to the non-exposed area, which is the background part, can be collected, so that the photoreceptor l leaves the developing area. Sometimes a toner image 3 without fogging is obtained.

〔Example〕

FIG. 2 is a schematic configuration diagram when the image forming method according to the present invention is applied to an image recording apparatus.

In the figure, reference numeral 21 denotes a photoreceptor drum, and a transparent conductive film (21b) is vacuum-deposited on a transparent glass drum 21a, and a Ss-based photoreceptor is deposited by vacuum evaporation.

Around the photoreceptor drum 21, a magnetic brush developing device 22,
A transfer roller 30 made of a conductive rubber roller is arranged,
A recording pulse 27 is applied to the magnetic brush developing device 22, and a transfer voltage (+5 oov) 31 is applied to the transfer roller 30, respectively. The magnetic brush developing machine 22 consists of a non-magnetic sleeve 22a and a magnet roller 22b, and the relative rotation of the two transports the conductive magnetic toner in a direction opposite to the running direction of the 26"ft photoreceptor drum 210. On the other hand, Inside the photosensitive drum 21, an LED exposure system 25 consisting of a 240 dpi LED array 25a and a selfoc lens 25b is provided at a position facing the magnetic brush developing device 22.

Further, an LED array bar 24 is provided as a static elimination light source.

Next, the recording procedure of the image recording apparatus shown in FIG. 2 will be explained. First, the photoreceptor drum 21 is moved at a circumferential speed of, for example, 501a/! l
Rotate in the direction of the arrow in the figure.

While conveying the toner through the magnetic brush developing machine 22, the LED
An optical system 25 performs image exposure. At this time, a recording pulse is applied to the sleeve 25a in synchronization with the image exposure.

FIG. 3 shows the recording pulses applied at this time.

The recording voltage value is -250V, and the OFF state is 30V. The recording period is determined to be 2.1 as from 240 dpi (9.4 dots/11 l) and a circumferential speed of 50 m/s. The recording pulse width was 0.1 ms. As a result, the duty ratio of the recording pulse remains at 4.8 inches. By applying the image gIn light and the recording pulse, photocarriers are generated in the image area, move to the surface of the photoreceptor, and form latent image charges 28. Next, the potential of the sleeve is fixed at 30V upon completion of the application of the recording pulse. As a result, toner in the background area is electrostatically collected and an image is formed. As mentioned above, the duty ratio of the recording pulse is 4.8%, and when converted to the movement wJtt of the photosensitive drum, it becomes 5 μm for one period of recording width of 106 μm. This value is sufficiently small that toner hardly adheres to it.

The toner image 23 formed as described above is transferred onto the recording paper 29 by the transfer row 230, and becomes a toner image 32 on the recording paper.

Thereafter, the image is fixed to the recording paper 29 by a fixing device (not shown), and becomes a permanent image record.

Residual toner 3 remaining on the photosensitive drum 21 without being transferred
: The static electricity is removed by the 1lt LED arrayper 24, and the electrostatic bonding force is weakened. The toner 34 whose charge has been removed in this way is collected by the magnetic brush developing device 22 and used again for recording.

The above procedure is repeated to perform continuous recording. According to this embodiment, there is an effect that recording can be performed at a low voltage using a simple developing machine consisting of one stage of rollers.

As another embodiment of the present invention, a case will be described in which a two-component developer consisting of a carrier and a toner is used. The configuration of the applied image recording apparatus is the same as the embodiment shown in FIG.

In this embodiment, the carrier is a resin carrier in which about 80% of magnetic powder is mixed into the resin. Also, the particle size is 15μ
m, resistivity is 10'Ω. In addition to these carriers, iron powder, ferrite carriers, etc. can be used. As the toner, an insulating toner having a particle size of 10 to 15 μm was used. The toner density of the developer can be recorded in 20 to 40 quadrants.

In this example, the value of the recording pulse is -500 to -600V.
is appropriate, and 30 to 60V in the OFF state is appropriate. According to this embodiment, in contrast to the above-mentioned embodiments in which the transfer characteristics at high humidity may deteriorate, there is an advantage that stable transfer characteristics can be obtained by using an insulating toner.

In yet another embodiment, a cleaner such as a brush or blade may be provided to remove residual toner on the photoreceptor.

Further, it can also be applied to a display in which a toner image on a photoreceptor is directly viewed without being transferred to a recording paper.

Regarding these embodiments, the shape of the photoreceptor is not limited to a drum, and the photoreceptor layer may be formed on an endless film. Furthermore, a photoreceptor having an insulating layer provided on the photoconductive layer can also be used. In this case, since the photoconductive layer is protected by the insulating layer, there is an advantage that the life of the photoreceptor can be extended. A further advantage is that the insulating layer allows the latent image charge and the toner to form a complete electric double layer, resulting in a more uniform toner image than in the case of a photoconductive layer alone. Furthermore, the material for the photoconductive layer is not limited to selenium-based photoreceptors (a-
A photoreceptor with high mobility such as 8iCdS can be used.

In addition, a laser, a liquid crystal shutter, an E
It is also possible to use an optical system using L or the like.

〔Effect of the invention〕

According to the present invention, a pulse-like recording voltage is applied to the sleeve of the developing machine during image exposure, and at other times, it is maintained at a potential of opposite polarity to the recording voltage (contrast developing potential). This makes it possible to perform image formation and contrast development, and provides a simple low-voltage image forming method.

[Brief explanation of drawings]

Fig. 1 is a diagram for explaining the present invention in detail, Fig. 2 is a diagram for explaining a conventional example, and Fig. 2 is a diagram for explaining a second conventional example.
It is. In the figure, 1 is a photoreceptor, 1a is a transparent substrate, 1b is a transparent or semi-transparent conductive layer, 1c is a photoconductive layer, 2 is a developing device, 2
a is a sleeve, 2b is a magnet roller, 3 is a toner image, 5 is an image exposure means, 6 is a toner, 7 is a pulse voltage application means, and 8 is a latent image charge. Completion 1 Kuni Ujikata and I line /) Theory Sunzuki To] Funeral 2 Utsuyuki's employment Vsu 1 Dero zuhata 3 Diagram moxibustion East Chiguri's blind love Day g3 I 4 Ikuto 1's inkling Ikuri / l san ann outside
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Claims (2)

[Claims] (1) Transparent substrate (1a), transparent or semitransparent conductive layer (1)
b), a photoreceptor (1) formed by sequentially laminating photoconductive layers (1c);
), a conductive non-magnetic sleeve (2a) and a magnet roller (2b) provided on the photoconductive layer (1c) side of the photoreceptor (1).
a developing device (2) that supplies positively or negatively charged toner onto the photoconductor 1; and a developing device (2) on the transparent substrate (1a) side of the photoconductor (1).
The image exposure means (5) provided opposite to the photoconductor (1) is provided to imagewise expose the photoconductor (1), and to form a toner image (
3), a first voltage value (7a) for moving the positively or negatively charged toner (6) from the developer (2) side onto the photoreceptor (1) and depositing )
and a second voltage value (7b) for collecting the toner (6) adhered onto the photoconductor (1) toward the developing device (2). A pulse voltage applying means is provided to apply a pulse voltage to the sleeve (
2b) An image forming method characterized in that a toner image (3) is formed by applying voltage onto the toner image (3). (2) The image forming method according to claim (1), wherein the pulsed voltage is applied for a time shorter than the image exposure time for applying the first voltage value. .