JP2002103668A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To further reduce in size an image forming apparatus, to form a more simple constitution at a low cost by further reducing a number of components and to more stably write an electrostatic latent image. SOLUTION: The writing electrode 3b of a writing unit 3 charges or discharges the latent image carrier 2 mainly between the electrode 3b and the carrier 2. The electrostatic latent image is written on the carrier 2 by charging or discharging by the electrode 3b on the carrier 2 set to a uniform charging state by a latent image carrier uniform charging controller 7. The latent image is developed by a developing unit 4 and its developer image is transferred to a transfer material 5 such as paper or the like by a transfer unit 6. Since the electrode 3a is used in the unit 3, the apparatus is reduced in size and simplified.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of an image forming apparatus for forming an image by forming an electrostatic latent image on a latent image carrier by a writing electrode of a writing device.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as an electrostatic copying machine or a printer, generally, the surface of a photoconductor is uniformly charged by a charging device, and a laser beam is applied to the surface of the uniformly charged photoconductor. Alternatively, an electrostatic latent image is written on the surface of the photoconductor by exposing light of an exposure device such as LED lamp light. Then, the electrostatic latent image on the surface of the photoconductor is developed by a developing device to form a developer image on the surface of the photoconductor, and the developer image is transferred to a transfer material such as paper by a transfer device, and the image is formed. Has formed. In such a conventional general image forming apparatus, the exposing device, which is a writing device for an electrostatic latent image, is constituted by a laser light generating device, an LED lamp light generating device, or the like. And it has a complicated configuration.

Therefore, as an apparatus for writing an electrostatic latent image, an image forming apparatus for writing an electrostatic latent image on the surface of a latent image carrier using electrodes without using laser light or LED lamp light is disclosed in Japanese Patent Publication No. Sho 63 (1988).
-45014. The image forming apparatus disclosed in this publication includes a multi-stylus having a large number of needle electrodes, and the needle electrode of the multi-stylus is simply brought into contact with the inorganic glass layer on the surface of the latent image carrier. Then, when a voltage is applied to the corresponding stylus electrode of the multi-stylus according to the input signal of the image information, the stylus electrode forms an electrostatic latent image on the latent image carrier. According to the image forming apparatus disclosed in this official gazette, since the conventional exposure apparatus is not used as the writing apparatus, the image forming apparatus has a small and relatively simple configuration.

Further, by controlling the ions generated by the corona discharger at the tip of the insulating substrate by an ion control electrode which is not in contact with the latent image carrier, an electrostatic latent image is formed on the latent image carrier. An image forming apparatus to be written is disclosed in
No. 6206 proposes this. Even in the image forming apparatus disclosed in this publication, the exposure apparatus is not used as the writing device, so that the image forming apparatus has a small and relatively simple configuration.

[0005]

However, in the image forming apparatus disclosed in the above-mentioned official gazette, a large number of needle electrodes of the multi-stylus are simply brought into contact with the inorganic glass layer on the surface of the latent image carrier. In addition, it is difficult to bring a large number of needle electrodes into stable contact with the inorganic glass layer on the surface of the latent image carrier. For this reason, it is difficult to stably charge the surface of the latent image carrier, and it is difficult to obtain a good image.

Further, in order to prevent the surface of the latent image carrier from being damaged by the contact of a large number of needle electrodes, it is necessary to provide an inorganic glass layer on the surface of the latent image carrier. It gets complicated. In addition, since the inorganic glass layer has extremely good physical adsorption water characteristics, water is well adsorbed on the surface of the inorganic glass, and the electric conductivity of the glass surface is increased by the adsorbed water, so that the charge of the latent image carrier is reduced. Because of the leakage, it is necessary to provide a means for drying the surface of the latent image carrier on which moisture is adsorbed to prevent the influence of the physically adsorbed water. Therefore, there is a problem that not only the device becomes larger, but also the number of parts increases, the configuration becomes more complicated, and the cost becomes higher.

[0007] Further, since a large number of needle electrodes are discharged,
There is also a problem that ozone (O ₃ ) is likely to be generated. This ozone, not only to generate a rust in the component in the apparatus, nitric acid generated reacts with NO _x (HN
O ₃ ) may cause the resin component to melt. In addition, there is a possibility that an odor is generated by ozone. For this reason, ozone must be discharged from the inside of the device. For that purpose, it is necessary to provide a duct and an ozone filter to provide a sufficient exhaust system, which not only increases the size of the device, but also increases the number of parts and increases the configuration. It becomes more complicated and expensive.

In the image forming apparatus disclosed in the above-mentioned publication, the ion control electrode controls the ions generated by the corona discharger, and does not directly inject the electric charge into the latent image carrier. Not only does the image forming apparatus have to be large, but also the configuration is extremely complicated. Moreover, because of the charging by ions,
It is difficult to stably write an electrostatic latent image on a latent image carrier. Further, since ozone is basically generated due to generation of ions, a problem similar to that of the image forming apparatus disclosed in the above-mentioned official gazette occurs.

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and an object of the present invention is to further reduce the number of parts and to further reduce the number of parts to achieve a simpler and cheaper configuration. Another object of the present invention is to provide an image forming apparatus capable of writing an electrostatic latent image more stably. Another object of the present invention is to provide an image forming apparatus capable of further suppressing generation of ozone.

[0010]

In order to solve this problem, the present invention is directed to a latent image carrier on which an electrostatic latent image is formed, and the electrostatic latent image is formed on the latent image carrier. A writing device for writing, and a developing device for developing the electrostatic latent image on the latent image carrier; and a developing device for writing the electrostatic latent image written on the latent image carrier by the writing device. An image forming apparatus that forms an image by developing the latent image carrier with a writing electrode for writing the electrostatic latent image on the latent image carrier; and a flexible base material that supports the writing electrode. Writing the electrostatic latent image by the writing electrode,
The writing by discharge between the writing electrode and the latent image carrier is dominant.

Further, the invention of claim 2 is characterized in that the writing electrode is in contact with the latent image carrier. Further, the invention according to claim 3 is characterized in that the writing electrode is not in contact with the latent image carrier. Further, the invention according to claim 4 is characterized in that the voltage applied to the write electrode is a voltage in which an AC component is superimposed on a DC component. Further, the invention of claim 5 is characterized in that the resistance of the write electrode is set to 10 ⁸ Ωcm or less. Further, the invention of claim 6 is characterized in that the resistance of the write electrode is set to 10 ⁶ Ωcm or more.

[0012]

In the image forming apparatus of the present invention having the above-described structure, the writing electrode charges or removes electricity from the latent image carrier mainly by discharging between the writing electrode and the latent image carrier. Thus, the electrostatic latent image can be easily written on the latent image carrier. Further, since the write electrode is supported by the flexible base material, the position of the write electrode with respect to the latent image carrier is stable, and the discharge between the write electrode and the latent image carrier is stable and reliable. Will be performed. As a result, the latent image carrier is more stably charged or neutralized by the writing electrode, so that the electrostatic latent image can be stably written by the latent image carrier, and a good image can be surely and reliably obtained. It can be obtained with high precision.

Further, the flexible substrate allows the writing electrode to come into contact with the latent image carrier with a small pressing force or to come closer to the latent image carrier without fail. The spatial gap with the image carrier becomes extremely small. This reduces the chance of unnecessary ionization of the air in the spatial gap, so that the generation of ozone is further suppressed and an electrostatic latent image can be formed at a low potential.

Further, since only a writing electrode is used as a writing device, a conventional large-sized laser light generating device, LED lamp light generating device and the like are not required. Therefore, the size of the apparatus is further reduced, and the number of parts is further reduced, so that a simpler and less expensive image forming apparatus can be obtained.

In particular, in the third aspect of the present invention, the writing electrode is arranged in non-contact with the latent image carrier, but at this time, the gap between the writing electrode and the latent image carrier is set to be small. As a result, more stable charging or discharging can be performed. In the invention according to claim 4, a superimposed voltage of a DC component and an AC component is applied to the write electrode. The superimposed voltage further stabilizes the charging or static elimination of the latent image carrier, and the AC component causes the writing electrode to vibrate, thereby removing foreign substances adhering to the writing electrode. Dirt is prevented.

Further, according to the fifth aspect of the present invention, the resistance of the write electrode is set to 10 ⁸ Ωcm or less,
A predetermined time constant is secured, and uniform charging can be obtained. Furthermore, in the invention of claim 6, by setting the resistance of the writing electrode to 10 ⁶ Ωcm or more, electrostatic damage due to pinholes in the charged layer of the latent image carrier 2 can be prevented. .

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram schematically showing a basic configuration of an embodiment of an image forming apparatus according to the present invention. As shown in FIG. 1, an image forming apparatus 1 according to the present invention
Is a latent image carrier 2 on which an electrostatic latent image is formed, a writing device 3 that contacts the latent image carrier 2 and writes an electrostatic latent image on the latent image carrier 2, A developing device 4 for developing the above electrostatic latent image with the developer carried and conveyed by the developer carrier 4a, and a developer image on the latent image carrier 2 developed by the developing device 4 on paper or the like A transfer device 6 that transfers the latent image carrier 2 to the transfer material 5, and removing the charge remaining on the latent image carrier 2 after the transfer or charging the latent image carrier 2 after the transfer.
Latent image carrier uniform charge control device 7 for making the upper part a uniform charge state
And at least. In the following description, all the latent image carriers 2 are described as being grounded, but this is for convenience of description, and the present invention is limited to the case where the latent image carrier 2 is grounded. is not.

The writing device 3 is an FPC (Flexible Print C).
An insulating material such as ircuit (hereinafter abbreviated as FPC) or PET (polyethylene terephthalate, abbreviated as PET) or the like, which has a high insulating property, is relatively soft and elastic, and is supported by the base material 3a. And a writing electrode 3b for writing an electrostatic latent image by being lightly pressed onto the latent image carrier 2 with a weak elastic restoring force due to the bending of the substrate 3a.

In the image forming apparatus 1 configured as described above, the latent image carrier 2 is controlled by the latent image carrier uniform charge control device 7.
After the upper portion is brought into the uniformly charged state, the electrostatic latent image is written on the latent image carrier 2 in the uniformly charged state by the writing device 3 in contact with the latent image carrier 2. Then, the electrostatic latent image on the latent image carrier 2 is developed with the developer of the developing device 4, and the developer image is transferred to the transfer material 5 by the transfer device 6. In the present invention, a state in which the charge on the latent image carrier 2 is eliminated and neither (+) nor (-) is uniformly on the latent image carrier 2 is also a uniform charge state. And

FIG. 2 is a view showing a basic process of image formation in the image forming apparatus 1 of the present invention. As a basic process of image formation in the image forming apparatus 1 of the present invention,
(1) Uniform charge removal-Contact charge writing-Regular development, (2) Uniform charge removal-Contact charge writing-Reversal development, (3) Uniform charge-Contact charge removal writing-Regular development, and (4) One There are four image forming processes, namely, charge removal, contact charge removal writing, and reversal development. Hereinafter, these image forming processes will be described.

(1) Uniform charge removal / contact charging writing / regular development As an example of this image forming process, there is a process shown in FIG. As shown in FIG. 2A, in this image forming process, a photoreceptor 2a is used as a latent image carrier 2, and a neutralization lamp 7a is used as a latent image carrier uniform charge control device 7. . The writing electrode 3b of the writing device 3 comes into contact with the photoconductor 2a and (+) charges the image portion of the photoconductor 2a to write an electrostatic latent image on the photoconductor 2a. Further, a bias voltage in which an alternating current is superimposed on a direct current (-), for example, is applied to the developing roller 4a of the developing device 4 as in the related art, and the developing roller 4a is charged with the developer 8 charged to the negative (-). Is conveyed toward the photoreceptor 2a. It should be noted that a DC-only bias voltage (-) can be applied to the developing roller 4a.

In the image forming process of this example, the charge on the surface of the photosensitive member 2a is removed by the charge removing lamp 7a, and the surface of the photosensitive member 2a is brought into a uniform charge state close to 0 V from which the charge has been removed. The image portion on the photoconductor 2 a is (+) charged by the writing electrode 3 b of the writing device 3, and this photoconductor 2
The electrostatic latent image is written on a. Then, the (-) charged developer 8 conveyed by the developing roller 4a of the developing device 4 adheres to the (+) charged image portion of the photoconductor 2a, and the electrostatic latent image is regularly developed.

As another example of the image forming process, there is a process shown in FIG. As shown in FIG. 2B, in this image forming process, a dielectric 2b is used as the latent image carrier 2, and a charge eliminating roller 7b is used as the latent image carrier uniform charge control device 7. . A DC bias voltage of, for example, (-) is applied to the developing roller 4a of the developing device 4 as in the related art. Incidentally, a bias voltage in which alternating current is superimposed on direct current (-) can be applied to the developing roller 4a. Further, the charge removing roller 7b
, An AC bias voltage is applied. The other configuration of the image forming process of this example is the same as the example shown in FIG.

In the image forming process of this embodiment, the charge removing roller 7b is in contact with the dielectric 2b, and the charge on the dielectric 2b is removed by the charge removing roller 7b, and the charge on the dielectric 2b is removed. A uniform charge state close to 0 V is set. The subsequent image forming operation is the same as the example shown in FIG. 2A except that the photoconductor 2a is changed to the dielectric 2b.

(2) Uniform charge removal-contact charging writing-reversal development As an example of this image forming process, there is a process shown in FIG. As shown in FIG. 2C, in this image forming process, as in the example shown in FIG. 2A, the photosensitive member 2a is used as the latent image carrier 2 and the latent image carrier 2 A charge eliminating lamp 7a is used as the charge control device 7. The writing electrode 3b of the writing device 3 comes into contact with the photoconductor 2a and charges the non-image portion of the photoconductor 2a (-). The other configuration of the image forming process of this example is the same as the example shown in FIG.

In the image forming process of this embodiment, the charge on the photosensitive member 2a is removed by the charge removing lamp 7a, and the photosensitive member 2a is brought into a uniform charge state close to 0 V from which the charge has been removed. The non-image portion on the photoreceptor 2a is (-) charged by the writing electrode 3b of the loading device 3, and this photoreceptor 2a
An electrostatic latent image is written thereon. Then, the (−) charged developer 8 conveyed by the developing roller 4 a of the developing device 4 adheres to the (−) uncharged image portion near 0 V on the photoreceptor 2 a, and the electrostatic latent image is reversely developed. You.

As another example of the image forming process, there is a process shown in FIG. As shown in FIG. 2D, in this image forming process, the dielectric 2b is used as the latent image carrier 2 as in the example shown in FIG. As the control device 7, a charge eliminating roller 7b is used. Further, the writing electrode 3b of the writing device 3 comes into contact with the dielectric 2b to charge the non-image portion of the dielectric 2b (-). The other configuration of the image forming process of this example is the same as the example shown in FIG.

In the image forming process of this embodiment, the charge removing roller 7b is in contact with the dielectric 2b, and the charge on the dielectric 2b is removed by the charge removing roller 7b, and the charge on the dielectric 2b is removed. A uniform charge state close to 0 V is set. The subsequent image forming operation is the same as that of the example shown in FIG.

(3) Uniform charging-contact charge erasing writing-normal development As an example of this image forming process, there is a process shown in FIG. As shown in FIG. 2E, in this image forming process, a photosensitive member 2a is used as the latent image carrier 2, and a charging roller 7c is used as the latent image carrier uniform charge control device 7. . This charging roller 7c
Is applied with a bias voltage in which an alternating current is superimposed on a direct current of (+), and the charging roller 7c moves (+) on the photosensitive member 2a.
To be uniformly charged. The charging roller 7
A bias voltage of (+) DC only can be applied to c. The writing electrode 3b of the writing device 3 is
a, the (+) charge of the non-image portion of the photosensitive member 2a is removed. The other configuration of the image forming process of this example is the same as the example shown in FIG.

In the image forming process of this embodiment, after the charging roller 7c is brought into contact with the photosensitive member 2a, the photosensitive member 2a is (+) charged by the charging roller 7c to be in a uniform charge state of a predetermined voltage. Then, the (+) charge of the non-image portion on the photoconductor 2a is removed by the writing electrode 3b of the writing device 3, and an electrostatic latent image is written on the photoconductor 2a. And
Conveyed by the developing roller 4a of the developing device 4 (-)
The charged developer 8 adheres to the (+) charged image portion of the photoconductor 2a, and the electrostatic latent image is developed normally.

As another example of the image forming process, there is a process shown in FIG. As shown in FIG. 2F, in this image forming process, a dielectric 2b is used as the latent image carrier 2, and a charging corona discharger 7d is used as the latent image carrier uniform charge control device 7. Have been. Although not shown, the charging corona discharger 7d includes:
DC bias voltage of (-) or (-)
A bias voltage in which an alternating current is superimposed on a direct current is applied.
Further, the writing electrode 3b of the writing device 3 comes into contact with the dielectric 2b to eliminate the (-) charge in the non-image portion of the dielectric 2b. Further, a DC bias voltage of (+) is applied to the developing roller 4a, and the developing roller 4a conveys the developer 8 charged to (+) toward the dielectric 2b. The developing roller 4a has (+)
Alternatively, a bias voltage in which the direct current and the alternating current are superimposed can be applied. The other configuration of the image forming process of this example is the same as the example shown in FIG.

In the image forming process of this example, after the dielectric 2b is charged (-) by the charging corona discharger 7d to have a uniform charge state of a predetermined voltage, the writing device 3
Of the non-image portion on the photoreceptor 2a by the writing electrode 3b
The charge is removed, and an electrostatic latent image is written on the dielectric 2b. Then, the (+) charged developer 8 conveyed by the developing roller 4a of the developing device 4 adheres to the (−) charged image portion of the dielectric 2b, and the electrostatic latent image is regularly developed.

(4) Uniform charging-contact charge removing writing-reversal development As an example of this image forming process, there is a process shown in FIG. 2 (g). As shown in FIG. 2G, in this image forming process, a photosensitive member 2a is used as the latent image carrier 2, and a charging roller 7c is used as the latent image carrier uniform charge control device 7. . This charging roller 7c
Is applied with a bias voltage in which an alternating current is superimposed on a direct current (−), and the charging roller 7c moves on the photoconductor 2a (−).
To be uniformly charged. The charging roller 7
It is also possible to apply a (−) DC only bias voltage to c. The writing electrode 3b of the writing device 3 is
a, the (-) charge of the image portion of the photosensitive member 2a is eliminated. The other configuration of the image forming process of this example is the same as the example shown in FIG.

In the image forming process of this embodiment, after the charging roller 7c is brought into contact with the photosensitive member 2a, the photosensitive member 2a is (-) charged by the charging roller 7c to a uniform charge state of a predetermined voltage. The (-) charge of the image portion on the photoconductor 2a is eliminated by the writing electrode 3b of the writing device 3, and an electrostatic latent image is written on the photoconductor 2a. Then, the (-) charged developer 8 transported by the developing roller 4a of the developing device 4 adheres to the (-) non-charged image portion of the photoconductor 2a, and the electrostatic latent image is reversely developed.

As another example of the image forming process, there is a process shown in FIG. As shown in FIG. 2H, in this image forming process, a dielectric 2b is used as the latent image carrier 2, and a charging corona discharger 7d is used as the latent image carrier uniform charge control device 7. Have been. Although not shown, the charging corona discharger 7d includes:
DC bias voltage of (+) or (+) as before
A bias voltage in which an alternating current is superimposed on a direct current is applied.
Another configuration of the image forming process of this example is the same as that of FIG.
This is the same as the example shown in FIG.

In the image forming process of this example, after the dielectric 2b is charged (+) by the charging corona discharger 7d to have a uniform charge state of a predetermined voltage, the writing device 3
The (+) charge of the image portion on the photoconductor 2a is eliminated by the writing electrode 3b, and an electrostatic latent image is written on the dielectric 2b. Then, the (+) charged developer 8 transported by the developing roller 4a of the developing device 4 adheres to the (+) uncharged image portion of the dielectric 2b, and the electrostatic latent image is reversely developed.

FIG. 3 illustrates the principle of writing an electrostatic latent image by charging or discharging the writing electrode 3b of the writing device 3.
(A) is an enlarged view of a contact portion between the writing electrode 3b and the latent image carrier 2, (b) is an electrical equivalent circuit diagram of this contact portion, and (c) to (f) each parameter and the latent image carrier. FIG. 4 is a diagram showing a relationship with a surface potential of a body 2. As shown in FIG. 3 (a), the latent image carrier 2 is made of a conductive material such as aluminum, and has a grounded base 2c and an insulative charged body formed on the outer periphery of the base 2c. And a layer 2d. The writing electrode 3b supported by the base material 3a made of FPC or the like of the writing device 3 is in contact with the charging layer 2d with a predetermined light pressing force as described above, and the latent image carrier 2 is Is moving (rotating) at the speed v. This small pressing force has a width of 300 mm and a pressing force of 10 N or less, that is, a linear pressure of 0.03.
N / mm or less is the contact between the writing electrode 3b and the latent image carrier 2 or the proximity of the writing electrode 3b to the latent image carrier 2 (writing electrode 3b).
It is preferable to stabilize the air gap between the b and the latent image carrier 2 and stabilize the charge injection or discharge. desirable.

[0038] The writing electrodes 3b, a predetermined high voltage V ₀ or a predetermined low voltage V ₁ is adapted to be applied selectively switched through the substrate 3a (±, as described above
High voltage means a voltage with a high absolute value,
The low voltage has the same polarity as the high voltage and has a low absolute value or 0V. In the description of the present invention in this specification, all of the low voltage is a ground voltage, so in the following description, the high voltage V _{0 is referred} to as a predetermined voltage V ₀ ,
The low voltage V ₁ that the ground voltage V _1. It goes without saying ground voltage V ₁ is 0V. ).

That is, an electrical equivalent circuit shown in FIG. 3B is formed at a contact portion (nip portion) between the writing electrode 3b and the latent image carrier 2. In FIG. 3B,
R indicates the resistance of the writing electrode 3b, and C indicates the capacitance of the latent image carrier 2. Resistance R of the writing electrode 3b is the A side - is adapted to be selectively switched for connection to a predetermined voltage V ₀ or the ground voltage V ₁ of the B-side ().

In the equivalent circuit, the write electrode 3b is connected to the A side, and the resistance R of the write electrode 3b and the latent image carrier 2 when a predetermined voltage V ₀ (−) is applied to the write electrode 3b. the relationship between the surface potential of FIG. 3 (c) to the next predetermined voltage V ₀ the surface potential of the latent image carrier 2 is constant in the region resistance R of the writing electrode 3b is small as shown by the solid line, the writing electrodes When the resistance 3b is larger than a predetermined value, the absolute value of the surface potential of the latent image carrier 2 decreases. On the other hand, the relationship between the resistance R of the writing electrode 3b and the surface potential of the latent image carrier 2 when the writing electrode 3b is connected to the B side and the writing electrode 3b is grounded is shown in FIG. approximately ground voltages V ₁ becomes the resistance R is the surface potential of the latent image carrier 2 is small region of a certain writing electrode 3b as indicated by the dotted line, the resistance R of the writing electrode 3b is a larger area than a predetermined value Then, the absolute value of the surface potential of the latent image carrier 2 increases.

[0041] In the region which is a predetermined voltage V ₀ or constant at the ground voltage V ₁ of the resistor R is small surface potential of the latent image carrier 2 is constant writing electrode 3b, as shown in FIG. 4 (a) Writing electrode 3b contacting latent image carrier 2 and latent image carrier 2
Is injected directly from the lower voltage to the higher voltage with the charged layer 2d. That is, the latent image carrier 2 is charged or eliminated by charge injection. In a region where the resistance R of the writing electrode 3b is large and the surface potential of the latent image carrier 2 starts to change, the charge or static elimination of the latent image carrier 2 due to charge injection gradually decreases, and the writing electrode 3b The resistance R of FIG.
As shown in (b), discharge occurs between the substrate 3a and the latent image carrier 2.

The discharge generated between the substrate 3a and the substrate 2c of the latent image carrier 2 starts at the absolute value of the voltage (predetermined voltage V ₀ ) between the substrate 3a and the latent image carrier 2. Although occurs when it becomes greater than the voltage V _th, the relationship between the gap between the substrate 3a and the image bearing member 2 and the discharge starting voltage V _th is as shown in FIG. 4 (c) by the Paschen's law. That is, when the gap is about 30 μm, the discharge start voltage V _th is the smallest, and when the gap is smaller or larger than about 30 μm, the discharge start voltage V _th becomes larger, and the discharge hardly occurs. This discharge also causes the surface of the latent image carrier 2 to be charged or neutralized. However, when the resistance R of the writing electrode 3 is in this range, the charging or discharging of the latent image carrier 2 due to charge injection is large, and the charging or discharging of the latent image carrier 2 due to discharge is small. Charge or charge elimination is dominated by charge or charge elimination by charge injection. In or removal of charge by the charge injection, the surface potential of the latent image carrier 2 becomes to the predetermined voltage V ₀ or the ground voltage V ₁ applied to the writing electrode 3b. In the case of charging by charge injection, the predetermined voltage V ₀ supplied to the writing electrode 3 b is set to be equal to or lower than a discharge starting voltage V _{th at which} a discharge occurs between the writing electrode 3 b and the base 2 c of the latent image carrier 2. It is desirable to do.

In a region where the resistance R of the writing electrode 3b is larger, the charging or discharging of the latent image carrier 2 due to the charge injection is small, and the charging or discharging of the latent image carrier 2 due to the discharge is the charging or discharging due to the charge injection. The charge or charge of the latent image carrier 2 gradually becomes dominant in the charge or charge by discharge. That is, when the resistance R of the writing electrode 3b increases, the surface of the latent image carrier 2 is charged or eliminated mainly by discharging, and the latent image carrier 2 is hardly charged or eliminated by charge injection. In or removal of charge by the discharge, the surface potential of the latent image carrier 2 becomes a voltage obtained by subtracting the discharge starting voltage V _th from the predetermined voltage V ₀ or ground voltages V ₁ is applied to the writing electrode 3b. The same applies to the case where the predetermined voltage V ₀ is a voltage of (+).

Therefore, the resistance R of the electrode 3b is changed by the latent image
A predetermined voltage | V where the surface potential of the carrier 2 is constant₀｜ (±
Pressure, so it is expressed in absolute value) or constant ground voltage
V₁And the writing electrode 3
a predetermined voltage V ₀And ground voltage V₁Between
Latent image by charge injection by switching control
The support 2 can be charged or neutralized.
You.

The write electrode 3b is connected to the A side to
A predetermined voltage V of (-) is applied to the write electrode 3b. ₀When applying
The relationship between the capacitance C of the latent image carrier 2 and the surface potential of the latent image carrier 2
The relation is as shown by the solid line in FIG.
In a region where C is small, the surface potential of the latent image carrier 2 is constant.
Constant voltage V₀And the capacitance C of the dielectric 2b is larger than a predetermined value.
In the threshold region, the absolute value of the surface potential of the latent image carrier 2 decreases.
I do. On the other hand, the write electrode 3b is connected to the B side to
The capacity C of the latent image carrier 2 when the pole 3b is grounded and the latent image carrier
The relationship with the surface potential of the holding body 2 is shown by a dotted line in FIG.
In the region where the capacity C of the latent image carrier 2 is small,
Substantially the ground voltage V where the surface potential of the body 2 is constant ₁And the latent image
In a region where the capacity C of the carrier 2 is larger than a predetermined value,
The absolute value of the surface potential of the holder 2 increases.

Then, in a region where the capacity C of the latent image carrier 2 is small and the surface potential of the latent image carrier 2 is a constant predetermined voltage V ₀ or a constant ground voltage V ₁ , the latent image carrier 2 contacts the latent image carrier 2. Direct (−) charge injection is performed between the writing electrode 3 b and the charged layer 2 d of the latent image carrier 2. That is, the latent image carrier 2 is charged or eliminated by charge injection. Further, in a region where the capacitance C of the latent image carrier 2 is large and the surface potential of the latent image carrier 2 starts to change, the charge or static elimination of the latent image carrier 2 due to charge injection gradually decreases, and the latent image carrier 2 As the capacitance C of the body 2 is increased, FIG.
As shown in (b), discharge occurs between the substrate 3a and the latent image carrier 2. This discharge also causes the surface of the latent image carrier 2 to be charged or neutralized. However, when the capacity C of the latent image carrier is in this region, the charge or static elimination of the latent image carrier 2 due to charge injection is large, and the charge or static elimination of the latent image carrier 2 due to discharge is small. Charging or discharging is dominated by charging or discharging by charge injection. In the charging or discharging by the charge injection, the surface potential of the latent image carrier 2 is changed to the predetermined voltage V ₀ or the ground voltage V ₁ applied to the writing electrode 3b.
Becomes

In a region where the capacitance C of the latent image carrier 2 is even larger, this charge is hardly injected between the writing electrode 3b and the charged layer 2d of the latent image carrier 2. That is, the latent image carrier 2 is not charged or neutralized by charge injection. The same applies to the case where the predetermined voltage V ₀ is a voltage of (+).

Accordingly, the capacitance C of the latent image carrier 2 is changed to a predetermined voltage | V ₀ | (the surface voltage of the latent image carrier 2 is represented by an absolute value because of the ± voltage) or a constant ground voltage. and sets a small region to be a V _1, by switching control between the voltage applied to the writing electrode 3b and the predetermined voltage V ₀ and the ground voltage V _1, the latent image carrier 2 by charge injection or It is possible to perform static elimination.

Further, the write electrode 3b is connected to the A side to
A predetermined voltage V of (-) is applied to the write electrode 3b. ₀When applying
Speed (peripheral speed) v of latent image carrier 2 and surface of latent image carrier 2
The relationship between the latent image and the potential is shown by the solid line in FIG.
In a region where the speed v of the carrier 2 is relatively low, the latent image carrier 2
Surface potential increases as the velocity v increases,
When the speed v of the latent image carrier 2 becomes larger than a predetermined value, the latent image
The absolute value of the surface potential of the carrier 2 is a constant voltage. Latent image
The surface potential of the carrier 2 increases as the speed v of the latent image carrier 2 increases.
The difference between the writing electrode 3b and the latent image carrier 2
Frictional charging of the latent image carrier 2 due to friction between
It is thought to be due to. This triboelectric charging is
When the speed v of the holding body 2 increases to some extent, it does not change,
It becomes constant. On the other hand, the write electrode 3b is connected to the B side.
And the speed v of the dielectric 2b when the write electrode 3b is grounded.
The relationship with the surface potential of the dielectric 2b is indicated by a dotted line in FIG.
As shown in FIG.
Pressure V₁Becomes The predetermined voltage V₀Is the voltage of (+)
But the same is true.

Further, the write electrode 3b is connected to the A side to
A predetermined voltage V of (-) is applied to the write electrode 3b. ₀When applying
The pressing force of the writing electrode 3b against the latent image carrier 2 (hereinafter simply referred to as writing
And the surface potential of the latent image carrier 2
The relationship between the write electrode 3b and the write electrode 3b as shown by the solid line in FIG.
In the region where the pressure is extremely small, the surface of the latent image carrier 2
The potential increases as the pressure of the writing electrode 3b increases.
And the pressure of the writing electrode 3b becomes larger than a predetermined value.
Then, the absolute value of the surface potential of the latent image carrier 2 is a constant voltage.
Becomes The surface potential of the latent image carrier 2 is the pressure of the writing electrode 3b.
As the write electrode 3b and the latent image bear,
The contact with the holder 2 increases with the increase in the pressure of the writing electrode 3b.
It is thought that it is because it becomes more certain.
The certainty of the contact between the writing electrode 3b and the latent image carrier 2 is as follows.
It does not change when the pressure of the writing electrode 3b increases to some extent.
And almost constant. On the other hand, write electrode 3b is connected to B side
Of the write electrode 3b when the write electrode 3b is grounded.
The relationship between the pressure and the surface potential of the latent image carrier 2 is shown in FIG.
Is constant irrespective of the pressure of the writing electrode 3b as shown by the dotted line in FIG.
Ground voltage V₁Becomes The predetermined voltage V₀Is (+)
The same is true for pressure.

In this way, the resistance R of the writing electrode 3b and the capacitance C of the latent image carrier 2 are set so that the surface potential of the latent image carrier 2 becomes a constant predetermined voltage. 2 and the pressure of the writing electrode 3b are controlled so that the surface potential of the latent image carrier 2 becomes a predetermined voltage, and the voltage applied to the writing electrode 3b is controlled to the predetermined voltage V ₀ and the ground voltage V _1.
By performing switching control between these steps, charging or discharging of the latent image carrier 2 by charge injection can be performed reliably and easily.

Although the predetermined voltage V ₀ applied to the write electrode 3b is a DC voltage in the above-described example, an AC voltage can be superimposed on the DC voltage. When the AC voltage is superimposed, the DC component is set to a voltage applied to the latent image carrier 2, the amplitude of the AC component is set to be twice or more the discharge start voltage Vth, and the frequency of the AC component is set to the latent image carrier. Preferably, the frequency of the rotation of the body 2 is about 500 to 1000 times (for example, if the diameter of the latent image carrier 2 is 30φ and the peripheral speed of the latent image carrier 2 is 180 mm / sec, the latent image carrier 2 Since the frequency at the rotation of is 2 Hz,
The frequency of the AC component is 1000 to 2000 Hz).
By superimposing the AC voltage on the DC voltage in this way, the charging or static elimination by the discharge of the writing electrode 3b becomes more stable, and the writing voltage is vibrated by the AC voltage, so that the writing electrode 3b adheres to the writing electrode 3b. Foreign matter can be removed, and contamination of the writing electrode 3b can be prevented.

Next, the flexible substrate 3a that supports the writing electrode 3b of the writing device 3 will be described. FIG. 5 is a schematic view of the latent image carrier 2 as an example of the writing device 3 as viewed from the axial direction. As described above, the base material 3a is made of a flexible material having relatively soft elasticity such as FPC.
Writing electrodes 3 to the distal end portion 3a ₁ of the substrate 3a, as shown in
b is fixed. Since the writing electrodes 3b are arranged in a plurality of rows in the axial direction (main scanning direction) of the latent image carrier 2 as described later, the base material 3a holds the latent image carrier in the axial direction of the latent image carrier 2. It is formed in a rectangular plate shape having a length substantially equal to the axial length of the charging layer 2d of the body 2. The end 3a ₂ of the writing electrode 3b of the substrate 3a and the opposite side is fixed by a suitable fixing member. The substrate 3a is provided so as to extend from the right side in FIG. 5 so as to oppose the rotation direction of the latent image carrier 2 (clockwise direction indicated by an arrow). The substrate 3a may be provided so as to extend in the same direction as the rotation direction of the latent image carrier 2 from the left in FIG.

In this state, the substrate 3a is slightly elastically bent to generate a weak elastic restoring force, and the writing electrode 3b is lightly pressed on the latent image carrier 2 with a small pressing force by the elastic restoring force. Pressed and in contact. Thus, the write electrode 3b
Is small, the wear of the charged layer 2d of the latent image carrier 2 by the writing electrode 3b is suppressed, and the durability is improved. Since the writing electrode 3b is in contact with the charged layer 2d by the elastic force, the writing electrode 3b comes into stable contact with the charged layer 2d. Incidentally, the end portion 3a ₂ of the substrate 3a, the driver 11 which controls the operation of the writing electrode 3b to be described later is fixed.

As shown in FIG. 5, when the substrate 3a is provided so as to oppose the rotation direction of the latent image carrier 2, foreign matters adhering to the latent image carrier 2 can be removed, and When the substrate 3a is provided in the same direction as the rotation direction of the latent image carrier 2, the foreign matter adhering to the latent image carrier 2 is removed from the substrate 3a. Latent image carrier 2
You will be able to get through.

FIG. 6 is a schematic diagram of another example of the writing device 3 as seen from the axial direction of the latent image carrier 2. Although the above example is set simply to resiliently slightly flexed state by a rectangular plate-shaped base member 3a is fixed to its end 3a _2, the writing device 3 of this embodiment, As shown in FIG. 6, a rectangular plate-shaped substrate 3a made of the same material as the substrate 3a of the above-described example.
Is bent in a hairpin curve shape along a line in the axial direction of the latent image carrier 2 at a central portion in a direction orthogonal to the axial direction of the latent image carrier 2, and both ends 3 a ₁ and 3 a ₂ thereof are appropriately formed. Is fixed by the fixing member. In this case, a conductive mounting plate (shield) for preventing crosstalk between the two portions of the base material 3a bent up and down in the figure is provided between both end portions 3a ₁ and 3a ₂ of the base material 3a. ) 10 is interposed.

In this example, the length of the substrate 3a in the axial direction of the latent image carrier 2 is set to be substantially the same as the length of the charged layer 2d of the latent image carrier 2 in the axial direction. a predetermined position of the hairpin-shaped portion (bent portion) 3a _3, the writing electrodes 3b are a plurality of rows fixed in the axial direction of the latent image carrier 2. Then, as shown in FIG.
a _1, 3a in a state _{where 2} is fixed, hairpin-shaped portions 3a ₃ of the substrate 3a are deflected slightly elastically, writing a weak elastic restoring force of hairpin-shaped portions 3a ₃ of the substrate 3a The electrode 3b is lightly pressed onto the latent image carrier 2 and is in contact therewith. In the writing device 3 of this example, since the base material 3a is supported by both ends 3a ₁ and 3a ₂ ,
The writing electrode 3b comes into contact more reliably and more stably. In FIG. 6, both ends 3a ₁ , 3a of the base material 3a are shown.
It is shown at a ₂ that the driver 11 of the electrode 3 b is fixed, which shows the electrode arrangement pattern shown in FIG. 9 described later.

FIG. 7 shows an arrangement pattern when a plurality of write electrodes 3b are arranged in the axial direction of the latent image carrier 2.
(A) is a diagram showing the case of the simplest write electrode array pattern, and (b) and (c) are diagrams showing the case of the write electrode array pattern solving the problem of (a), respectively. . The simplest arrangement pattern of the plurality of write electrodes 3b is such that a plurality of rectangular write electrodes 3b are arranged in a line in the axial direction of the latent image carrier 2 as shown in FIG. In this case, among the plurality of writing electrodes 3b, driving control by switching the writing electrodes 3b writing electrode 3b is their respective predetermined number (eight in the illustrated example) to a predetermined voltage V ₀ or ground voltages V ₁ The plurality of sets are connected to a single driver 11 and are arranged in a line in the axial direction of the latent image carrier 2.

However, when the simple rectangular write electrodes 3b are simply arranged in a line in the axial direction of the latent image carrier 2, a gap is generated between the adjacent write electrodes 3b. For this reason, the surface of the latent image carrier 2 facing this gap becomes a non-charged portion that is not charged or a non-static portion that is not removed. Therefore, in the arrangement pattern of the write electrodes 3b in the example shown in FIG. 7B, the write electrodes 3b are formed in a triangular shape, and the directions of the write electrodes 3b of the adjacent triangles are opposite to each other (erect triangles). State and inverted state). In that case, the plurality of write electrodes 3b
Opposite ends of the triangular bases of the adjacent write electrodes 3b overlap (overlap) in a direction orthogonal to the axial direction of the latent image carrier 2 (rotation direction of the latent image carrier 2; sub-scanning direction). It is arranged as follows. In this way, by making a part of the adjacent writing electrode 3b overlap each other in a direction orthogonal to the axial direction of the latent image carrier 2, the above-described non-charged portion or No non-static elimination part is formed, and the entire surface of the latent image carrier 2 can be charged. Also in this example, a plurality of sets in which a predetermined number of write electrodes 3b are connected to one driver 11 are arranged. The shape of the write electrode 3b is not limited to a triangle, and may be, for example, a trapezoid, a parallelogram, a shape having an inclined side at least at a part of the opposite side of the adjacent write electrode 3b, or a side opposite to the adjacent write electrode 3b. Any shape can be used as long as a part of the adjacent write electrodes 3b, such as a shape having irregularities, overlaps with each other in a direction orthogonal to the axial direction of the latent image carrier 2. Also in this example, as in the example shown in FIG. 7A, a plurality of sets in which a predetermined number of adjacent electrodes 3b are connected to one driver 11 are arranged, and each driver 11 has the same side with respect to the electrode 3b. Are located in

The write electrode 3b of the example shown in FIG.
In the arrangement pattern described above, the write electrodes 3b are formed in a circular shape, and the plurality of circular write electrodes 3b are arranged in two rows and in a staggered manner in a direction orthogonal to the axial direction of the latent image carrier 2. . In this case, the write electrodes 3b adjacent to each other in the first and second rows are arranged so that a part of the write electrodes 3b overlap each other in a direction orthogonal to the axial direction of the latent image carrier 2 of the latent image carrier 2. ing. Even in the arrangement pattern of the write electrodes 3 in this example, the above-described non-charging portion or non-static elimination portion is not formed on the surface of the latent image carrier 2, and the entire surface of the latent image carrier 2 can be charged. . In this example, a set in which a predetermined number of electrodes 3b of an adjacent first column electrode 3b and a second column electrode 3b are connected to one driver 11 is arranged in the axial direction of the latent image carrier 2 in plural sets. At the same time, each driver 11 is arranged on the same side with respect to the electrode 3b. And
As shown in FIG. 8, each driver 11 is formed on a base material 3a and has a conductive pattern (Cu) formed of, for example, a copper (Cu) foil having a rectangular cross section and having a thin flat plate shape (the cross sectional shape is shown in FIG. 11 described later). Similarly, each driver 11 and each electrode 3b are electrically connected by the conductive pattern 9 formed on the base material 3a. These conductive patterns 9 can be formed by a conventional thin film pattern forming method such as etching. In FIG. 8, line data, a write timing signal, and high-voltage power are supplied to each driver 11 from above.

FIG. 9 is a diagram showing still another example of the arrangement pattern of the plurality of write electrodes 3b. As shown in FIG. 9, in the arrangement pattern of the write electrodes 3b in this example, the write electrodes 3b
Are formed in a rectangular shape, and a plurality of rectangular write electrodes 3b are arranged in two rows and in a staggered manner in a direction orthogonal to the axial direction of the latent image carrier 2 as in the example shown in FIG. In addition, the write electrodes 3 b adjacent to each other in the first and second rows are arranged so that a part of each write electrode 3 b overlaps in a direction orthogonal to the axial direction of the latent image carrier 2. Even in the arrangement pattern of the write electrodes 3 in this example, the above-described non-charging portion or non-static elimination portion is not formed on the surface of the latent image carrier 2, and the entire surface of the latent image carrier 2 can be charged. . In this example, a plurality of sets in which a predetermined number of electrodes 3b in the first column are connected to one driver 11 are arranged, and a predetermined number of electrodes 3b in the second column are connected to one driver 11.
Are connected in a plurality. In this case, the driver 11 for the first-row electrode 3b and the driver 11 for the second-row electrode 3b are disposed on opposite sides of the electrode 3b, respectively, and as shown in FIG. It is fixed to both ends 3a ₁ and 3a ₂ of the base material 3a bent in a hairpin curve shape.

FIG. 10 is a diagram showing still another example of the arrangement pattern of the plurality of write electrodes 3b. In the arrangement patterns of the write electrodes 3b in each of the examples shown in FIGS. 7C and 9 described above, the write electrodes 3b are arranged in two rows and in a staggered manner in the axial direction of the latent image carrier 2. However, as shown in FIGS. 10A and 10B, the arrangement pattern of the write electrodes 3b in this example is the same arrangement pattern in the axial direction of the latent image carrier 2 in the second row and the first row. For example, a trapezoidal write electrode 3
b and the second row of write electrodes 3 ′ b corresponding to the write electrodes 3 b and identical to the write electrodes 3 b.
Are arranged in a line with a predetermined gap in a direction perpendicular to the axial direction of the first direction. In other words, two identical write electrodes 3b, 3'b are provided so as to overlap in a direction orthogonal to the axial direction of the latent image carrier 2, so that the charged layer 2d of the latent image carrier 2 is more reliably formed. And more stably charged. Note that, as in the example shown in FIG. 7B described above, a part of the trapezoidal opposing oblique sides of the adjacent write electrode 3b or write electrode 3'b in the same row is in the axial direction of the latent image carrier 2. They overlap in orthogonal directions.

The example shown in FIG. 10C is different from the example shown in FIG. 10B in that the write electrodes 3b in the first row and the write electrodes 3'b in the second row are arranged with the trapezoidal directions reversed. In the example shown in FIG. 10D, two rows of rectangular write electrodes 3b arranged in a zigzag pattern shown in FIG. It is provided in a direction orthogonal to the axial direction of the body 2, and two identical write electrodes 3 b and 3 ′ b in each row are overlapped in a direction orthogonal to the axial direction of the latent image carrier 2. The operation and effect of these examples are the same as those of the example shown in FIG.

FIGS. 11A to 11D are cross-sectional views showing examples of the write electrode 3b of the writing device 3, respectively. In each of the writing electrodes 3b of the writing devices 3 in the above-described examples, the contact portions with the latent image carrier 2 are shown facing downward, but these FIGS. 11 (a) to 11 (d) are used. In each of the write electrodes 3b in each example, the contact portion with the latent image carrier 2 is illustrated upward.

In the writing device 3 of the example shown in FIG.
Conductive pattern (Cu pattern) formed on substrate 3a
9 is coated with a resistance layer 13 having a rectangular cross section to form a two-layer write electrode 3b. This resistance layer 13 can be coated by, for example, an inkjet printer,
Coating can also be performed by other conventionally known coating means other than the ink jet printer. When an ink jet printer is used, the thickness of the resistance layer 13 can be controlled with high accuracy, and the charging of the latent image carrier 2 can be controlled more accurately. When the resistance of the writing electrode 3b is set to 10 ⁸ Ωcm or less, a predetermined time constant is secured and uniform charging can be obtained. When the resistance of the writing electrode 3b is set to 10 ⁶ Ωcm or more, electrostatic damage due to a pinhole in the charged layer 2d of the latent image carrier 2 is prevented. Therefore, the resistance value of the resistance layer 13 of the write electrode 3b is 10 ⁶ Ωcm to 10 ⁸ Ωcm.
Ωcm is desirable.

In the writing electrode 3b of this embodiment, the surface of the resistance layer 13 is brought into surface contact with the charging layer 2d of the latent image carrier 2. Thus, by providing the resistance layer 13 on the conductive pattern 9 of the write electrode 3b,
This prevents the charge injection from spreading in the lateral direction.
Thereby, charge injection between the writing electrode 3b and the latent image carrier 2 is performed more effectively. Note that the cross-sectional shape of the resistance layer 13 is not limited to the rectangular shape shown in FIG.
In (a), it may be formed in an arc-shaped cross section in which the direction protruding upward and orthogonal to the axial direction of the latent image carrier 2 is the axial direction. If this section is formed in the shape of an arc column,
The resistance layer 13 comes into line contact with the charging layer 2d of the latent image carrier 2 in a direction perpendicular to the axial direction of the latent image carrier 2. Note that the line contact may be inclined in a direction orthogonal to the axial direction of the latent image carrier 2.

In the writing device 3 of the example shown in FIG.
The resistance layer 13 having a rectangular cross section in the example shown in FIG.
Instead, the upper part of the resistance layer 13 of the electrode 3b is formed as a hemispherical projection projecting upward. Thereby, the resistance layer 1
3 has a spherical surface, and comes into point contact with the charging layer 2d of the latent image carrier 2. The resistance layer 13 and the charging layer 2d
Charge injection is performed at the point contact portion with and the charge leaks therearound, and the charge injection is performed. Therefore, the charged layer 2d is charged or discharged by the charge injection. Moreover, the resistance layer 1
Since the surface of No. 3 is spherical, discharge is performed in the vicinity of the point contact portion between the resistance layer 13 and the charging layer 2d. Therefore, this discharge also causes the charging layer 2
d is charged or neutralized. In addition, the above-described non-charged portion and non-charged portion are not formed on the charged layer 2d by the charging or discharging of the charged layer 2d by the discharge. In addition, the point contact makes it possible for foreign substances adhering to the surface of the latent image carrier 2 to easily pass through, thereby preventing the surface of the latent image carrier 2 from filming. Furthermore, the resistance layer 13 is made of a material that is easy to be shaved. The surface of the resistance layer 13 is shaved and refreshed, so that the initial surface is always maintained and filming is prevented.

In the writing device 3 of the example shown in FIG.
The upper part of the example shown in FIG.
And the surface of the substrate 3a are overcoated with a protective layer 14. The protective layer 14 makes it difficult for the surface of the resistive layer 13 to be shaved and for foreign substances to be hardly attached. In the writing device 3 of the example shown in FIG. 11D, the surface of the base material 3a supporting the writing electrode 3b having the spherical resistance layer 13 on the upper part of the example shown in FIG. Are provided so as to be able to roll. These fine particles 12 allow foreign matter to easily pass between the writing electrode 3b and the latent image carrier 2, so that good lubrication can be obtained between the writing electrode 3b and the foreign matter, and writing can be performed. Foreign matter is prevented from adhering to the electrode 3b. These fine particles 12 are set to a very small diameter of 1 μm or less and are formed of a transparent resin such as acrylic. As described above, by forming the fine particles 12 with the transparent resin, even if these fine particles 12 move to the image area, the image area is not affected by these fine particles 12.

FIGS. 12A and 12B show examples of the resistance layer 13 provided on the write electrode 3b of the conductive pattern 9, respectively. As shown in FIG. 12A, in the writing electrode 3b of this example, a medium resistance layer 13a is provided over the entire surface of the conductive pattern 9 where the electrode is formed. The middle resistance layer 13a has the largest thickness at the center of the write electrode 3b, and gradually decreases toward the periphery. Further, a high resistance layer 13b having a higher resistance than the medium resistance layer 13a is provided on the medium resistance layer 13a. In that case, the thickness of the resistance layer 13 is made constant throughout, and the middle resistance layer 13a is exposed in a predetermined region at the center. Therefore, the high-resistance layer 13b has the largest thickness at the periphery of the write electrode 3b, and gradually decreases toward the center, and further has a predetermined area at the center where the middle-resistance layer 13a is exposed. Not provided. Thereby, the write electrode 3b
Is set smaller than the resistance of the peripheral portion of the write electrode 3b, the charge injection between the write electrode 3a and the latent image carrier 2 is large at the central portion of the write electrode 3b, and It becomes smaller at the periphery of the input electrode 3b. The write electrode 3b is mainly configured in a three-layer structure.

Then, the electric charge leaks between the conductive pattern 9 and the latent image carrier through the exposed portion of the medium resistance layer 13a so that the electric charge is injected, and the electric conduction between the conductive pattern 9 and the latent image through the high resistance layer 13b. Electric discharge is carried out with the carrier. Therefore, by making the resistance of the high resistance layer 13 larger than the resistance of the medium resistance layer 13a by a predetermined value or more, the charging or discharging of the latent image carrier 2 by discharging is more dominant than the charging or discharging by charge injection. Because
The latent image carrier 2 is charged or discharged mainly by discharging. By setting the resistance at the center of the write electrode 3b to be smaller than the resistance at the peripheral edge of the write electrode 3b, the electric field at the edge of the write electrode 3b is reduced. Thereby, the transfer residue at the portion corresponding to the edge of the write electrode 3b is reduced.

In the example shown in FIG. 12B, the write electrode 3b
A middle resistance layer 13a is provided at the center of
A high resistance layer 13b is provided around the middle resistance layer 13a on the periphery of the write electrode 3b. The thicknesses of the medium resistance layer 13a and the high resistance layer 13b are both set to the same constant thickness. Also in the writing electrode 3b of this example, the discharge of the latent image carrier 2 is performed by making the resistance of the high resistance layer 13 larger than the resistance of the middle resistance layer 13a by a predetermined value or more, as in the above-described example. It can be set so that the charge or charge removal due to charge becomes more dominant than the charge or charge removal due to charge injection. Other functions and effects of the write electrode 3b of this example are the same as those of the above-described example.

FIG. 13 is a view similar to FIG. 5, showing another example of the image forming apparatus of the present invention. In each of the above-described examples, the writing electrode 3b is assumed to be in contact with the latent image carrier 2, but in the image forming apparatus 1 of this example, the writing electrode 3b generates a discharge with respect to the latent image carrier 2. In such a manner that they are separated by a predetermined gap (proximity distance). That is, FIG.
As shown in FIG. 3, an insulating layer 28 is provided on the surface of the substrate 3a facing the latent image carrier 2. In this case, the insulating layer 2
8 is from above the conductive pattern 9 formed on the base material 3a.
The writing electrode 3b at the electrode portion of the conductive pattern 9 is formed so as to be exposed. The thickness of the insulating layer 28 is set to be larger than the thickness of the write electrode 3b by a predetermined thickness.

The insulating layer 28 is lightly pressed onto the latent image carrier 2 with a weak elastic restoring force due to the bending of the substrate 3a and is in contact therewith. Since there is a difference in thickness between the insulating layer 28 and the writing electrode 3b, when the insulating layer 28 comes into contact with the latent image carrier 2, the writing electrode 3b (Proximity distance). The close distance is set to, for example, about 30 to 100 μm, and can be adjusted by the thickness of the insulating layer 28. The adjustment of the close distance can be performed in the process of forming the insulating layer 28, for example, in the process of applying the insulating photoresist to the base material 3a when the insulating layer 28 is formed of an insulating photoresist. FIGS. 14A to 14C show write electrodes 3b provided so as to be close to the latent image carrier 2, respectively.
12 is a sectional view similar to FIG. 11, showing each example of FIG. As in FIG. 11, in FIGS. 14A to 14C, each of the write electrodes 3 b in each example is illustrated with the contact portion with the latent image carrier 2 facing upward.

In the example of the writing device 3 shown in FIG.
A predetermined number of foil-shaped conductive materials (copper foil) formed on the base material 3a
A conductive pattern (Cu pattern) 9 composed of a line 9a is formed, and a write electrode 3b is formed in an electrode forming portion of each conductive material line 9a. The insulating layer 28 is interposed between the adjacent conductive material lines 9a, and the insulating layer 28 is provided inside the conductive material line 9a adjacent to the endmost conductive material line 9a. Each of the write electrodes 3b of this example is connected to the latent image carrier 2
Is opposed to the surface of the charged layer 2d.

In the example of the writing device 3 shown in FIG.
The protective layer 29 is provided on the conductive material line 9a including the write electrode 3b and the insulating layer 28 in the example shown in FIG. The protective layer 29 provided on the conductive material line 9a connects the conductive material line 9a including the write electrode 3b to the conductive material line 9a temporarily.
_{When the 3} occurs, it is prevented from being rusted by this ozone. In addition, the protective layer 29 provided on the insulating layer 28 has lubricity to prevent abrasion of the insulating layer 28 due to contact with the latent image carrier 2, so that a predetermined contact between the latent image carrier 2 and the writing electrode 3 b can be obtained. The gap (close distance) is maintained.

In the writing device 3 of the example shown in FIG.
On the surface of the writing electrode 3b of the conductive pattern 9 in the example shown in FIG. These fine particles 12 allow foreign matter to easily pass between the writing electrode 3b and the latent image carrier 2, so that good lubrication can be obtained between the writing electrode 3b and the foreign matter, and writing can be performed. Foreign matter is prevented from adhering to the electrode 3b. Further, the gap between the writing electrode 3b and the latent image carrier 2 is kept constant by these fine particles 12. These fine particles 12 are set to a very small diameter of 1 μm or less and are formed of a transparent resin such as acrylic. As described above, by forming the fine particles 12 with the transparent resin, even if these fine particles 12 move to the image area, the image area is not affected by these fine particles 12. It should be noted that fine particles can also be provided on the insulating layer 28 to improve the lubrication between the insulating layer 28 and the latent image carrier 2.

FIG. 15 shows that a predetermined voltage V is applied to the write electrode 3b.₀You
And ground voltage V₁Switching times for switching connection
It is a figure showing a road. As shown in FIG. 15, for example, four rows
The arranged write electrodes 3b are connected to the corresponding high voltage
Switch (High Voltage Switch; H.V.S.W.) 15
These high-voltage switches 15 are
And the corresponding electrode 3b is set to a predetermined voltage V ₀And the ground voltage V1
The connection is switched. Each high voltage switch 1
5 are provided from the shift register (SR) 16 respectively.
An image writing control signal is input, and the shift register
Reference numeral 16 denotes an image signal stored in the buffer 17 and
And the clock signal from the clock 18 are input respectively.
You. Then, the image write control signal from the shift register 16 is sent.
Signal is written by the AND circuit 19 from the encoder 20.
Input to each high-voltage switch 15 based on the
Will be able to Each high voltage switch 15 and AND times
The supply voltage to each write electrode 3b is switched and controlled by the path 19.
The above-described driver 11 is configured.

FIG. 16 shows a state in which each high voltage switch 15 of each electrode 3b is selectively switched to a predetermined voltage V0 or a ground voltage V1, respectively, and FIG. 16 (a) shows a voltage state of each electrode. FIGS. 7B and 7B are diagrams showing a developer image when normal development is performed in the voltage state of FIG. 7A, and FIG. 7C is a diagram showing a developer image when reverse development is performed in the voltage state of FIG. As shown in FIG. 16, for example, the (n-2) th, the (n-1) th, and the nth
The (n + 1) -th and (n + 2) -th electrodes 3b are controlled to switch their respective high-voltage switches 15 as shown in FIG.
It is assumed that the voltage state shown in FIG. Therefore, when the electrostatic latent image is written on the latent image carrier 2 by each electrode in such a voltage state and the electrostatic latent image is developed by regular development, the developer 8 attached to a predetermined voltage V ₀ parts on the developer image is obtained as shown by hatching (shaded) in Figure 16 (b). Further, performs writing of an electrostatic latent image in the same manner, when developing the electrostatic latent image by reversal development, the developer 8 is deposited on the ground voltages V ₁ part of the latent image carrier 2, FIG. 1
A developer image as shown by hatching in FIG. 6C is obtained.

According to the image forming apparatus 1 using the writing device 3 configured as described above, the writing electrode 3 b is mainly charged by the discharge between the writing electrode 3 b and the latent image carrier 2. Since the carrier 2 is charged or neutralized, an electrostatic latent image can be easily written on the latent image carrier 2. Also, the writing electrode 3b is made of a flexible base material 3
a, the position of the writing electrode 3b with respect to the latent image carrier 2 is stabilized, and the discharge between the writing electrode 3b and the latent image carrier 2 can be performed stably and reliably. As a result, the latent image carrier 2 can be more stably charged or neutralized by the writing electrode 3b with higher accuracy, and thus the electrostatic latent image can be more stably written. An image can be obtained reliably and with high accuracy.

Further, the resistance of the write electrode is set to 10⁸Ωcm or less
By setting to, a predetermined time constant can be secured and uniform
A charge can be obtained. Further, the resistance of the write electrode 3b is reduced.
10 ⁶Ωcm or more, the latent image carrier 2
To prevent electrostatic damage due to pinholes in the charged layer 2d
Become so. Further, the write electrode 3b is placed on the conductive pattern.
Is provided with a resistance layer 13, so that the charge
Spread can be prevented.

Further, since the writing electrode 3b is merely brought into contact with the latent image carrier 2 with a small pressing force, the writing electrode 3b
Can prevent the latent image carrier 2 from being damaged, and the durability of the latent image carrier 2 can be improved. Furthermore, since only the writing electrode 3b is used as the writing device 3 and a large laser light generating device or an LED lamp light generating device as in the related art is not provided, the size of the device can be further reduced. As a result, the number of parts can be further reduced, and a simpler and less expensive image forming apparatus can be obtained.

Further, since the writing electrode 3b comes into contact with the latent image carrier 2 or comes close to the latent image carrier 2 with a small pressing force by the flexible base material 3a, the writing electrode 3b and the latent image The spatial gap with the carrier 2 is very small. This reduces the chance of unnecessary ionization of the air in the spatial gap, so that the generation of ozone is further suppressed and an electrostatic latent image can be formed at a low potential.

Next, a specific example of an image forming apparatus using the writing device of the present invention for writing an electrostatic latent image by bringing the electrode 3b into contact with the latent image carrier 2 will be described. FIG. 17 schematically shows an example of an image forming apparatus using the writing device of the present invention, and FIG.
FIG. 2 is a diagram illustrating an image forming apparatus having a cleaner, and FIG. 2B is a diagram illustrating a cleanerless image forming apparatus having no cleaner. The image forming apparatus 1 shown in FIG. 17A is a monochrome image forming apparatus, and a base material 3a of the writing device 3 extends from the upstream side in the rotation direction of the latent image carrier 2 to the downstream side. Write electrode 3b fixed to the tip of base material 3a
Is provided. Further, the latent image carrier 2 is transferred from the transfer device 6.
The cleaning device 21 is provided on the downstream side in the rotation direction of the cleaning device 21. Although not shown, between the writing device 3 and the cleaning device 21, the above-described latent image carrier uniform charge control device 7 is provided.
May be provided. If the latent image carrier uniform charge control device 7 is not provided, a latent image is formed by overwriting the previous latent image. It is possible to reduce the number of points and downsize the device.

In the monochrome image forming apparatus 1 configured as described above, after the surface of the latent image carrier 2 is uniformly charged by the latent image carrier uniform charge controller 7 in the same manner as described above, Each writing electrode 3b of the writing device 3 is mainly driven by a discharge between the writing electrode 3b and the latent image carrier 2.
Is charged or eliminated, a latent image is written on the surface of the latent image carrier 2. The latent image on the latent image carrier 2 is developed after the developer is adhered to the latent image carrier 2 by a developing roller 4a of a developing device 4 that is not in contact with the latent image carrier 2 and then developed. Is transferred to the transfer material 5 by the transfer device 6. The developer remaining on the latent image carrier 2 after the transfer is removed by the cleaning blade 21a of the cleaning device 21, and the surface of the cleaned latent image carrier 2 is made uniform again by the latent image carrier uniform charge control device 7. Charged state. The image forming apparatus 1 of this example is a writing apparatus 3 of the present invention.
, A smaller and simpler configuration can be achieved.

The image forming apparatus 1 shown in FIG. 17B is a cleanerless image forming apparatus which does not include the cleaning device 21 in the image forming apparatus 1 shown in FIG. In the image forming apparatus 1 of this example, the developing roller 4a of the developing device 4 is in contact with the latent image carrier 2, and performs contact development.

In the image forming apparatus 1 of this embodiment thus configured, the latent image carrier 2 and the latent image carrier 2 after the previous transfer are placed on the latent image carrier 2 by the unillustrated latent image carrier uniform charge controller 7. After both the remaining residual developer is brought into a uniform charge state, the surface of the latent image carrier 2 and the surface of the residual developer are charged or eliminated by the writing electrode 3b of the writing device 3, and the latent image carrier 2 is charged. An electrostatic latent image is written on the top and on the residual developer. Then, these electrostatic latent images are developed by the developing device 4. At this time, by selecting the charging line of the writing electrode 3b to be charged to the polarity that the developer 8 originally has, the residual developer in the non-image portion on the latent image carrier 2 is removed by the writing electrode 3b. Since it is charged to that polarity, it moves toward the developing device 4, and the residual developer in the image area on the latent image carrier 2 remains on the latent image carrier 2 and is used as a developer image. Become. By moving the residual developer in the non-image area toward the developing device 4 in this manner, the surface of the latent image carrier 2 can be cleaned without providing the cleaning device 21. In particular, although not shown, a brush is provided downstream of the transfer device 6 in the rotation direction of the latent image carrier 2, and the residual developer on the latent image carrier 2 is scattered and leveled by the brush, so that a non-image portion is formed. Some residual developer can be more effectively moved to the developing device 4 and removed.

Other image forming operations of the image forming apparatus 1 of this example are the same as those of the image forming apparatus 1 shown in FIG. The image forming apparatus 1 of this example can also have a smaller and simpler configuration by using the writing device 3 of the present invention. Configuration.

FIG. 18 is a diagram schematically showing another example of an image forming apparatus using the writing device of the present invention. As shown in FIG. 18, the image forming apparatus 1 of this example performs full-color development by superimposing four colors of black K, yellow Y, magenta M, and cyan C on the latent image carrier 2. And an endless belt-shaped latent image carrier 2 is provided. The endless belt-shaped latent image carrier 2 is stretched between two rollers 22 and 23, and is rotated clockwise in the drawing by a driving roller among the rollers 22 and 23.

Along the linear portion of the endless belt of the latent image carrier 2
And a writing device 3 for each color._K, 3_Y, 3_M, 3_Cand
Developing device 4_K, 4_Y, 4_M, 4_CIs in the rotational direction of the latent image carrier 2.
The colors K, Y, M, and C are arranged in this order from the upstream side. Mochi
Of course, these developing devices 4_K, 4 _Y, 4_M, 4_CIs other than shown
They can be arranged in any order. Writing equipment for each color
Place 3_K, 3_Y, 3_M, 3_CEach writing electrode 3b_K, 3b_Y, 3b_M, 3
b_CAre discharged between the latent image carrier 2 and the
Electricity is generated. Although not shown,
In the image forming apparatus 1 of this example also, the latent image carrier 2
End belt writing device 3_K, 3_Y, 3_M, 3_CStraight section opposite to
Is provided with the latent image carrier uniform charge control device 7 described above.
You.

[0090] In the image forming apparatus 1 of this embodiment configured in this way, an electrostatic latent image of black K is written on the surface of the latent image carrier first with electrodes 3b _K of the writing device 3 _K for black K together, black K electrostatic latent image is developed with the surface of the latent image bearing member 2 by the developing device 4 _K of the black K
Is formed. Next, the electrostatic latent image of cyan C is applied to the latent image carrier 2 _{C by} the electrode 3b _C of the writing device 3 _C for cyan _C.
With written superimposed on and on the developer image of black K surfaces of cyan C developer image on an electrostatic latent image of the cyan C is developed in the surface of the latent image bearing member 2 by the developing device 4 _C Is formed. Similarly, after the electrostatic latent image of magenta M is written on top of each developer image of the latent image bearing member 2 and the black K and cyan C by electrodes 3b _M of the writing device 3 _M of magenta M , an electrostatic latent image of magenta M is the magenta developer image M is formed on each developer image on the surface of being developed by the developing device 4 _M latent image carrier 2 and black K and cyan C, further, Electrode 3b _C of writing device 3 _C for cyan _C
After the electrostatic latent image of cyan C is written on the latent image carrier 2 and the developer images of black K, cyan C, and magenta M, the electrostatic latent image of cyan C is developed by the developing device 4 _C
To form a cyan C developer image on the surface of the latent image carrier 2 and on each of the black K, cyan C and magenta M developer images, and color-matching. Then, these developer images are transferred. A full-color developer image in which the developer images of the respective colors are color-matched on the transfer material 5 by the device 6 is formed. The order of forming the developers of each color can be set to any order other than the order described above. As described above, even in a full-color image forming apparatus in which the developer images of the respective colors are superimposed on the latent image carrier 2 and color-matched, the use of the writing device 3 of the present invention makes the image forming apparatus smaller and simpler. Configuration.

FIG. 19 is a diagram schematically showing still another example of an image forming apparatus using the writing device of the present invention. FIG.
As shown in FIG. 1, in the image forming apparatus 1 of this example, the image forming apparatuses 1 _K , 1 _C , 1 _M , and 1 _Y for each color are tandemly arranged in this order from the upstream side in the moving direction of the transfer material 5. ing. The arrangement order of the image forming apparatuses 1 _K , 1 _C , 1 _M , and 1 _Y for each color can be set in any order. Each image forming apparatus 1 _K ,
1 _C , 1 _M , and 1 _Y are latent image carriers 2 _K , 2 _C , 2 _M ,
2 _Y , writing devices 3 _K , 3 _C , 3 _M , 3 _Y , developing devices 4 _K , 4 _C , 4 _M ,
4 _Y , and transfer devices 6 _K , 6 _C , 6 _M , 6 _Y. Although not shown, each of the image forming apparatuses _1K , _1C , _1M , and _1Y
Each of the same latent image carrier uniform charge control devices 7 as described above.
There writer 3 _K for each color, 3 _C, 3 _M, 3 each from _Y latent image carrier _{2 K, 2 C, 2 M} , 2 Y may be disposed in the upstream side in the rotation direction of the.

The image forming apparatus of this embodiment thus configured
In the apparatus 1, first, a black K image forming apparatus 1_KTo
The black K latent image carrier uniform charge control device 7
Therefore, the latent image carrier 2_KAfter the surface of the
Loading device 3_KElectrode 3b_KThe latent image of black K
Holding body 2_KThe surface of this black is written
K electrostatic latent image is developed by developing device 4_KImage carrier 2 developed with_K
A black K developer image is formed on the surface. This latent image
Carrier 2_KThe upper black K developer image is transferred to the transfer device 6_Kso,
The image is transferred to the supplied transfer material 5 and
A developer image of K is formed. Next, an image of cyan C
Forming device 1_C, The uniform charge of the cyan C latent image carrier
The latent image carrier 2 is controlled by the controller 7._CSurface is uniformly charged
After that, the writing device 3_CElectrode 3b_CAnd the electrostatic latent of cyan C
The image is a latent image carrier 2_COn the surface of the
Developing device 4_CLatent image developed in
Carrier 2_CA cyan C developer image is formed on the surface of the substrate.
This latent image carrier 2_CTransfer device for cyan C developer image
6_CAs a result, the supplied black K developer image is formed.
Is transferred onto the transferred transfer material 5, and the cyan C
A developer image is formed. Similarly, the image of magenta M
Forming device 1_MWriting device 3_MElectrode 3b _MSubmersible by
Image carrier 2_MWriting and developing device for magenta M electrostatic latent image
Place 4_MFor developing and transferring an electrostatic latent image of_MTransfer material 5
After the superimposition transfer of the magenta M developer image to
Yellow Y image forming apparatus 1_YWriting device 3_YNo electricity
Pole 3b _YLatent image carrier 2_YYellow Y electrostatic latent image
Writing and developing device 4_YFor developing and transferring electrostatic latent images
Place 6_YTransfer of the yellow Y developer image to the transfer material 5
Then, the transfer material 5 is color-matched with the developer image of each color.
A full-color developer image is formed. Thus, each color image
Image forming apparatus 1_K, 1_C, 1_M, 1_YIs located in tandem
The writing apparatus of the present invention is also applicable to a multicolor image forming apparatus.
3 makes it more compact and simpler
Can be

FIG. 20 shows an image using the writing apparatus of the present invention.
It is a figure which shows the further another example of a forming apparatus typically. FIG.
Image forming apparatus 1 of each color shown in FIG._K, 1_C, 1_M, 1_YBut tongue
In the image forming apparatus 1 arranged in dem, each image forming apparatus
1_K, 1_C, 1_M, 1_YLatent image carrier 2_K, 2_C, 2_M, 2_YFormed into
The developer images of the respective colors are transferred to the respective image forming apparatuses 1._K, 1_C, 1_M, 1_Y
Is transferred to the transfer material 5 every time.
In the image forming apparatus 1 shown in FIG.
Carrier 2_K, 2_C, 2_M, 2_YThe developer image of each color formed on
Once the intermediate transfer is performed, the image is transferred to the transfer material 5.
ing. That is, in the image forming apparatus 1 of this example,
The image forming apparatus 1 shown in FIG.
Have been killed. The intermediate transfer device 24 has an endless belt shape.
An intermediate transfer member 25 is provided.
Is stretched between two rollers 26 and 27.
Drive to rotate counterclockwise in the figure.
ing. Then, along the linear portion of the intermediate transfer body 25,
Each image forming apparatus 1_K, 1_C, 1 _M, 1_YIs arranged
At the same time, one transfer device 6 is provided at the position of the roller 27.
Have been. Another configuration of the image forming apparatus 1 of this example is shown in FIG.
9 is the same as the image forming apparatus 1 of the example shown in FIG.

In the image forming apparatus 1 of this embodiment configured as described above, the latent image carriers 2 _K , 2 _C , 2 _M , and 2 _Y of the respective colors are provided similarly to the image forming apparatus 1 of the example shown in FIG. The developer images of the respective colors are formed, and the developer images of the respective colors are color-matched in the same manner as when the developer images of the respective colors are transferred to the intermediate transfer body 25 on the transfer material 5 in the example shown in FIG. Is over-transferred. The developer image of each color intermediately transferred to the intermediate transfer body 25 is transferred to the transfer material 5 by the transfer device 6, and a full-color developer image is formed on the transfer material 5. Other image forming operations of the image forming apparatus 1 of this example are the same as those of the image forming apparatus 1 of the example shown in FIG. Thus, the intermediate transfer device 24
And a full-color image forming apparatus in which the image forming apparatuses 1 _K , 1 _C , 1 _M , and 1 _{Y of} each color are arranged in tandem.
By using the writing device 3 of the present invention, it is possible to make the configuration smaller and simpler.

FIG. 21 is a view similar to FIG. 5, schematically and partially showing still another example of the embodiment of the image forming apparatus according to the present invention. In each of the above-mentioned examples, the latent image carrier uniform charge control device 7 for uniformly charging the latent image carrier 2 is provided independently of the writing device 3. In the image forming apparatus 1 of the first embodiment, as shown in FIG.
Are provided integrally with the writing electrode 3b. That is,
The distal end portion 3a ₁ of the substrate 3a of the writing device 3, together with the uniform charge control electrode 7e of the image bearing member uniformly charge control device 7 is provided, the uniform charge control electrode 7e with a predetermined gap And the write electrode 3b is provided. In this case, the uniform charge control electrode 7e is formed in a thin plate shape having a rectangular cross section, and is continuous in the axial direction of the latent image carrier 2 by the same length as the axial length of the charged layer 2d of the latent image carrier 2. It has been extended. Each of the writing electrode 3b and the uniform charge control electrode 7 is in contact with the surface of the latent image carrier 2 with a small pressing force with a weak elastic restoring force due to the bending of the substrate 3a.

[0096] After the image forming apparatus 1 of this embodiment configured in this manner, the latent image bearing member 2 of the surface in a uniform charge control electrode 7e of the distal end portion 3a ₁ of the substrate 3a is uniformly charged,
The electrostatic latent image is written on the surface of the latent image carrier 2 when the writing electrode 3b charges or removes the latent image carrier by discharging. In the image forming apparatus 1 of this example,
Since the uniform charge control electrode 7e and the writing electrode 3b are provided integrally, the image forming apparatus 1 can be formed more compact and simpler. Other configurations and other operational effects of the image forming apparatus 1 of this example are the same as those of the example shown in FIG.

The uniform charge control electrode 7e and the write electrode 3
The integral provision of b is not limited to the example shown in FIG. 21 and can be applied to the image forming apparatus of the other example described above, and it is needless to say that the same operation and effect can be obtained. Further, an appropriate insulator can be provided in a gap between the writing electrode 3b and the uniform charge control electrode 7e.

[0098]

As is apparent from the above description, according to the image forming apparatus of the present invention, the writing electrode is formed on the latent image carrier mainly by the discharge between the writing electrode and the latent image carrier. On the other hand, since charging or static elimination is performed, the electrostatic latent image can be easily written on the latent image carrier. Further, since the write electrode is supported by the flexible base material, the position of the write electrode with respect to the latent image carrier is stabilized, and the discharge between the write electrode and the latent image carrier is stably and reliably performed. Can be done. This makes it possible to more stably charge or eliminate the latent image carrier by the writing electrode, so that the writing of the electrostatic latent image can be performed more stably.
A good image can be obtained reliably and with high accuracy.

Furthermore, since only a writing electrode is used as a writing device, a conventional large-sized laser light generation device, LED lamp light generation device, and the like can be eliminated. Therefore, the size of the apparatus can be further reduced, the number of components can be further reduced, and a simpler and less expensive image forming apparatus can be obtained.

Further, since the writing electrode is brought into contact with the latent image carrier with a small pressing force or is brought closer to the latent image carrier by the flexible base material, the writing electrode and the latent image holding The spatial gap with the body can be made very small. This can reduce the chance of unnecessary ionization of the air in the spatial gap, so that the generation of ozone can be further suppressed and an electrostatic latent image can be formed at a low potential.

In particular, according to the third aspect of the present invention, since the writing electrode is disposed in non-contact with the latent image carrier, the gap between the writing electrode and the latent image carrier is set to be small. Thereby, more stable charging or static elimination can be performed. According to the fourth aspect of the present invention, since the superimposed voltage of the DC component and the AC component is applied to the write electrode, the charging or discharging of the latent image carrier can be further stabilized, and the AC component can be further stabilized. As a result, the writing electrode vibrates,
Since foreign matter adhering to the write electrode can be removed, it is possible to prevent the write electrode from being stained.

Further, according to the fifth aspect of the present invention, by setting the resistance of the writing electrode to 10 ⁸ Ωcm or less, a predetermined time constant can be secured and uniform charging can be obtained. Further, according to the invention of claim 6, the resistance of the write electrode is set to 10 ⁶
By setting the value to Ωcm or more, electrostatic breakdown due to pinholes in the charged layer of the latent image carrier can be prevented.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a basic configuration of an embodiment of an image forming apparatus according to the present invention.

FIG. 2 is a diagram showing a basic process of image formation in the image forming apparatus of the present invention.

3A and 3B illustrate a principle of writing an electrostatic latent image by charging or discharging a writing electrode of a writing device, and FIG. 3A is an enlarged view of a contact portion between the writing electrode and a latent image carrier; FIG. 3B is an electrical equivalent circuit diagram of the contact portion, and FIGS. 3C through 3F are diagrams showing the relationship between each parameter and the surface potential of the latent image carrier.

4A and 4B are diagrams illustrating charging or discharging of a latent image carrier; FIG. 4A is a diagram illustrating charging or discharging of a latent image carrier by charge injection; FIG. 4B is a diagram illustrating charging or discharging of a latent image carrier by discharging; FIG. 3C is a diagram for explaining Paschen's law.

FIG. 5 is a schematic view of a latent image carrier of an example of a writing device as viewed from an axial direction.

FIG. 6 is a schematic view of a latent image carrier of another example of the writing device as viewed from an axial direction.

7A and 7B show an arrangement pattern when a plurality of write electrodes are arranged in the axial direction of the latent image carrier. FIG. 7A is a diagram showing the case of the simplest write electrode arrangement pattern. (C) is a diagram showing a case of an arrangement pattern of the write electrodes in which the problem of (a) is solved.

FIG. 8 is a diagram showing an arrangement pattern and a wiring pattern of a write electrode and a driver.

FIG. 9 is a diagram showing still another example of an arrangement pattern of a plurality of write electrodes.

FIG. 10 is a diagram showing still another example of an arrangement pattern of a plurality of write electrodes.

FIGS. 11A to 11D are cross-sectional views showing respective examples of write electrodes of the write device.

FIGS. 12A and 12B are diagrams showing examples of a resistive layer 13 provided on a writing electrode of a conductive pattern, respectively.

FIG. 13 is a view similar to FIG. 5, illustrating another example of the image forming apparatus of the present invention.

FIGS. 14A to 14C are cross-sectional views similar to FIG. 11, illustrating respective examples of the write electrode 3b provided so as to be close to the latent image carrier 2. FIGS.

FIG. 15 is a diagram showing a switching circuit for selectively connecting a predetermined voltage V ₀ and a ground voltage V ₁ to a write electrode.

FIG. 16 shows a state when each high-voltage switch of each electrode is selectively switched to a predetermined voltage V0 or a ground voltage V1, and FIG. 16A is a diagram showing a voltage state of each electrode;
FIG. 6B is a diagram illustrating a developer image when normal development is performed in the voltage state of FIG. 7A, and FIG. 7C is a diagram illustrating a developer image when reverse development is performed in the voltage state of FIG.

17A and 17B schematically show an example of an image forming apparatus using the writing device of the present invention, in which FIG. 17A shows an image forming apparatus provided with a cleaner, and FIG. 1 is a diagram illustrating an image forming apparatus.

FIG. 18 is a diagram schematically showing another example of the image forming apparatus using the writing device of the present invention.

FIG. 19 is a view schematically showing still another example of the image forming apparatus using the writing device of the present invention.

FIG. 20 is a diagram schematically showing still another example of the image forming apparatus using the writing device of the present invention.

FIG. 21 is a view similar to FIG. 5, schematically and partially showing still another example of the embodiment of the image forming apparatus according to the present invention.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 image forming apparatus 2 latent image carrier 3 writing apparatus 3
a: base material, 3b: writing electrode, 4: developing device, 5: transfer material, 6: transfer device, 7: latent image carrier uniform charge control device,
8 developer, 9 conductive pattern, 12 fine particles, 13
... resistive layer, 28 ... insulating layer

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Kaneo Yoda 3-3-5 Yamato, Suwa City, Nagano Prefecture Seiko-Epson Corporation (72) Inventor Nobumasa Abe 3-5-5 Yamato, Suwa City, Nagano Prefecture Seiko -Epson Corporation (72) Inventor Yujiro Nomura 3-3-5 Yamato, Suwa City, Nagano Prefecture Seiko-Epson Corporation F Term (Reference) 2C162 AE21 AE31 AE44 AE47 AF70 EA17 2H029 AA06 AB03 AB04 AB14 AC05 AD03 AD06 AE01

Claims (6)

[Claims] 1. A latent image carrier on which an electrostatic latent image is formed, a writing device for writing the electrostatic latent image on the latent image carrier, and a device for writing the electrostatic latent image on the latent image carrier An image forming apparatus comprising at least a developing device for developing, wherein the developing device develops the electrostatic latent image written on the latent image carrier by the writing device to form an image; A writing electrode for writing the electrostatic latent image on the latent image carrier, and a flexible base material supporting the writing electrode, wherein the writing of the electrostatic latent image by the writing electrode includes: An image forming apparatus characterized in that writing by discharge between the writing electrode and the latent image carrier is dominant. 2. The image forming apparatus according to claim 1, wherein said writing electrode is in contact with said latent image carrier. 3. The image forming apparatus according to claim 1, wherein the writing electrode is not in contact with the latent image carrier. 4. The image forming apparatus according to claim 1, wherein the voltage applied to the write electrode is a voltage in which an AC component is superimposed on a DC component. 5. The image forming apparatus according to claim 1, wherein the resistance of the writing electrode is set to be 10 ⁸ Ωcm or less. 6. The image forming apparatus according to claim 1, wherein the resistance of the writing electrode is set to 10 ⁶ Ωcm or more.