JP2002103667A - Image forming device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To further reduce the size of an image forming apparatus, further reduce the number of parts to make a simpler and less expensive configuration, and more stably write an electrostatic latent image. Do. An insulating layer (28) is provided on a base (3a) of a writing device (3), and the insulating layer (28) is in contact with the latent image carrier (2) with a small pressing force due to a weak elastic restoring force of the base (3a). . Thus, the writing electrode 3b of the writing device 3 is brought close to the latent image carrier 2 with a predetermined gap. An electrostatic latent image is written on the latent image carrier 2 on the latent image carrier 2 that has been brought into a uniform charge state by the latent image carrier uniform charge control device 7 by discharging or charging by the writing electrode 3b. .
The electrostatic latent image is developed by the developing device 4, and the developer image is transferred to the transfer material 5 such as paper by the transfer device 6. Since the writing electrode 3a is used for the writing device 3, the device is small and simple.

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 apparatus, and more particularly to a writing apparatus. The present invention belongs to the technical field of an image forming apparatus which forms an electrostatic latent image on a latent image carrier by bringing an embedded electrode close to the latent image carrier.

[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, wherein the developing device writes 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. Wherein the writing electrode is close to the latent image carrier so that discharge occurs between the writing electrode and the latent image carrier.

Further, according to a second aspect of the present invention, an insulating layer is provided on the flexible substrate, and the insulating layer contacts the latent image carrier, so that the writing electrode is connected to the latent image carrier. Is characterized by being close to Furthermore, the invention of claim 3 is characterized in that the writing electrode charges the latent image carrier to write the electrostatic latent image on the latent image carrier. Further, the invention according to claim 4 is characterized in that the writing electrode writes the electrostatic latent image on the latent image carrier by removing charges from the latent image carrier. The invention according to claim 5, wherein the writing electrode is configured to write the electrostatic latent image on the latent image carrier by switching connection between a high voltage and a low voltage according to an image to be formed. It is characterized by.

Further, according to a sixth aspect of the present invention, the writing device and the developing device are provided for each of black, yellow, magenta, and cyan, and the writing of each color on the latent image carrier is performed. The image forming apparatus is characterized in that the developer images of the respective colors are superimposed and formed by the apparatus and the developing device. Further, according to the invention of claim 7, the latent image carrier, the writing device and the developing device are provided for each color of black, yellow, magenta and cyan, so that the image forming device for each of these colors can be tandemly provided. It is characterized by being arranged. Further, the invention according to claim 8 is characterized in that an intermediate transfer device is provided for intermediately transferring the developer image for each color by the image forming apparatus for each color.

[0013]

In the image forming apparatus of the present invention having the above-described structure, the writing electrode is provided close to the latent image carrier, so that there is a gap between the writing electrode and the latent image carrier. Discharge occurs. This discharge causes the charge to move between the writing electrode and the latent image carrier, so that the electrostatic latent image is written on the latent image carrier by charging or discharging by the writing electrode. In this case, since the write electrode is supported by the flexible base material, the gap between the write electrode and the latent image carrier can be set flexibly. Therefore, the charging or discharging of the latent image carrier by the writing electrode is performed more stably and with high accuracy. As a result, the writing of the electrostatic latent image is performed more stably, so that a good image can be obtained reliably and with high accuracy. In particular, by bringing the insulating layer provided on the base material into contact with the latent image carrier, the gap between the writing electrode and the latent image carrier can be set more stably and more accurately. . Therefore, the charging or static elimination by the writing electrode is performed more stably and with high accuracy.

Further, since the writing electrode is brought close to the latent image carrier by the flexible base material, the spatial gap between the writing electrode and the latent 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 the write electrode is only in the vicinity of the latent image carrier, the damage of the latent image carrier by the write electrode is prevented, and the durability of the latent image carrier is improved. Further, even when the insulating layer is in contact with the latent image carrier, since the insulating layer is provided on the flexible base material, the pressing force with which the insulating layer presses the latent image carrier can be set extremely small. Further, damage to the latent image carrier by the flexible insulating layer is suppressed. Furthermore, only a writing electrode is used as a writing device, and a conventional large-sized laser light generator, LED lamp light generator, 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.

[0016]

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
A latent image carrier 2 on which an electrostatic latent image is formed, a writing device 3 for writing an electrostatic latent image on the latent image carrier 2, and an electrostatic latent image on the latent image carrier 2 A developing device 4 for developing with the developer carried and conveyed by the carrier 4a; and a transfer device 6 for transferring the developer image on the latent image carrier 2 developed by the developing device 4 to a transfer material 5 such as paper. And a latent image that uniformly charges the latent image carrier 2 by removing charges remaining on the latent image carrier 2 after transfer or charging the latent image carrier 2 after transfer. And at least a carrier uniform charge control device 7.
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 has a high insulation property such as FPC (abbreviation of Flexible Print Circuit, hereinafter referred to as FPC) or PET (abbreviation of polyethylene terephthalate, hereinafter referred to as PET) as shown in an enlarged manner in FIG. A flexible base material 3a which is relatively soft and elastic; and is provided near the latent image carrier 2 supported by the substrate 3a and formed on the base material 2c of the latent image carrier 2. A writing electrode 3b for writing an electrostatic latent image on the charging layer 2d. In addition, substrate 3
The insulating layer 28 is provided on the surface facing the latent image carrier 2 in FIG. In this case, the insulating layer 28 is formed such that the write electrode 3b connected to the conductive pattern 9 is exposed from above the conductive pattern 9 formed on the base material 3a as described later. The thickness of the insulating layer 28 is
The thickness is set to be larger than the thickness b 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 and the thickness of the charging layer 2d. The adjustment of the close distance is performed by the insulating layer 28.
For example, when the insulating layer 28 is formed of an insulating photoresist, the process can be performed in a process of applying the insulating photoresist to the base material 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 uniform charge state, the electrostatic latent image is written on the latent image carrier 2 in the uniform charge state by the writing electrode 3b of the writing device 3 which is close to 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. 3 is a diagram 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-Proximity charge writing-Regular development, (2) Uniform charge removal-Proximity charge writing-Reverse development, (3) Uniform charge-Proximity charge writing-Regular development, and (4) One There are four image forming processes, i.e., charge removal, proximity charge removal writing, and reversal development. Hereinafter, these image forming processes will be described.

(1) Uniform charge removal / proximity charging writing / regular development As an example of this image forming process, there is a process shown in FIG. As shown in FIG. 3A, in this image forming process, a photosensitive member 2a is used as the latent image carrier 2, and a static elimination lamp 7a is used as the latent image carrier uniform charge control device 7. . The writing electrode 3b of the writing device 3 is configured to write an electrostatic latent image on the photosensitive member 2a by (+) charging the image portion of the photosensitive member 2a in proximity to the photosensitive member 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. 3B, in this image forming process, a dielectric 2b is used as the latent image carrier 2, and a neutralizing 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. 3A except that the photoconductor 2a is changed to the dielectric 2b.

(2) Uniform charge removal-proximity charging writing-reversal development As an example of this image forming process, there is a process shown in FIG. As shown in FIG. 3 (c), this image forming process uses a photosensitive member 2a as the latent image carrier 2 and a uniform latent image carrier as in the example shown in FIG. 3 (a). As the charge control device 7, a charge removing lamp 7a is used. Further, the writing electrode 3b of the writing device 3 is configured to (-) charge a non-image portion of the photoconductor 2a in proximity to 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 of 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 photoconductor 2a is (-) charged by the writing electrode 3b of the device 3, and an electrostatic latent image is written on the photoconductor 2a. 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. 3D, 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 close to the dielectric 2b and charges 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 the above-described example shown in FIG. 3C except that the photoconductor 2a is changed to the dielectric 2b.

(3) Uniform charging-proximity static charge writing-normal development As an example of this image forming process, there is a process shown in FIG. As shown in FIG. 3E, 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
The (+) charge of the non-image portion of the photoconductor 2a is removed in the vicinity of a. 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. 3F, in this image forming process, a dielectric 2b is used as the latent image carrier 2, and a corona discharger 7d for charging 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 is arranged so as to be close to the dielectric 2b and to remove the (-) charge of 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-proximity charge removal writing-reversal development As an example of this image forming process, there is a process shown in FIG. As shown in FIG. 3G, in this image forming process, the photosensitive member 2a is used as the latent image carrier 2 and the 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 (-) charge of the image portion of the photosensitive member 2a is removed in the vicinity of a. 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. 3 (h), 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. 4 shows the charging of the writing electrode 3b of the writing device 3.
Or explain the principle of writing an electrostatic latent image by static elimination,
(A) Enlargement of the proximity of the writing electrode 3b and the latent image carrier 2
FIG. 3B is an electrical equivalent circuit diagram of the proximity portion, and FIG.
The chair (f) shows each parameter, the surface potential of the latent image carrier 2 and
FIG. As shown in FIG.
The holding body 2 is made of a conductive material such as aluminum and is grounded.
And a substrate 2c formed on the outer periphery of the substrate 2c.
And a charged body layer 2d having insulating properties. write
A book supported on a substrate 3a made of an FPC or the like of the device 3
As described above, the embedded electrode 3b is at a predetermined
The latent image carrier 2
Are moving (rotating) at a predetermined speed v. Write electrode 3b
Has a predetermined high voltage V₀Or a predetermined low voltage V₁Is the base material 3
a to be selectively switched and applied.
(Because there is ± charge as described above,
Voltage with high absolute value, low voltage is the same as high voltage
The polarity has a low absolute value or 0V. This specification
In the description of the invention in this document, all of this low voltage is grounded.
Therefore, in the following description, the high voltage V
₀Is a predetermined voltage V₀It is called low voltage V₁To the ground voltage V₁To
U. Ground voltage V ₁Is 0V
No. ).

That is, an electrical equivalent circuit shown in FIG. 4B is formed in the vicinity of the writing electrode 3b and the latent image carrier 2. 4B, 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 ().

[0039] In the equivalent circuit, the writing electrodes 3b are connected to the A side to the writing electrode 3b (-) of the writing electrode 3b upon application of the predetermined voltage V ₀ which resistor R and the latent image carrier 2 4C, the surface potential of the latent image carrier 2 becomes a constant voltage in a region where the resistance R of the writing electrode 3b is small as shown by a solid line in FIG. The constant voltage of this surface potential is
(Absolute value | V of predetermined voltage applied to write electrode 3b
₀ |)-(discharge start voltage V which is the voltage of write electrode 3b when discharge starts from write electrode 3b to latent image carrier 2
_th ) has a polarity of (-). When the resistance R of the writing electrode 3b is in a region larger than a predetermined value, the absolute value of the surface potential of the latent image carrier 2 decreases. On the other hand, when the write electrode 3b is connected to the B side and the write electrode 3b is grounded, the relationship between the resistance R of the write electrode 3b and the surface potential of the latent image carrier 2 is shown in FIG.
In the area where the resistance R of the writing electrode 3b is small as shown by the dotted line in FIG.
_When the resistance R of the writing electrode 3b is larger than a predetermined value, the absolute value of the surface potential of the latent image carrier 2 increases.

Then, the resistance R of the write electrode 3b is small,
In a region where the surface potential of the latent image carrier 2 is a constant voltage− (| V ₀ | −discharge starting voltage V _th ), the writing electrode 3b close to the latent image carrier 2 as shown in FIG. And latent image carrier 2
Is discharged from the lower electrode, that is, the writing electrode 3b, to the higher electrode, that is, the latent image carrier 2 with the charged layer 2d. That is, the latent image carrier 2 is uniformly charged or uniformly discharged by the discharge. In this example, the latent image carrier 2 is uniformly charged.

The discharge generated between the write electrode 3b and the latent image carrier 2 causes the discharge between the write electrode 3b and the substrate 2c of the latent image carrier 2.
_Occurs when the absolute value of the voltage (predetermined voltage V ₀ ) becomes larger than the discharge start voltage V _th, and the gap between the write electrode 3 b and the latent image carrier 2 and the discharge start voltage V _th
FIG. 5C shows the relationship with Paschen's law. That is, when the gap is about 30 μm, the discharge starting voltage V _th is the smallest, and the gap is about 30 μm.
Regardless of whether it is smaller or larger than m, the discharge starting voltage _Vth becomes large, and it becomes difficult for discharge to occur. This discharge causes the surface of the latent image carrier 2 to be charged or neutralized. Thus, in the case of charging or discharging by discharge, the writing electrode 3
The predetermined voltage V ₀ supplied to b is a discharge starting voltage V at which a discharge occurs between the writing electrode 3b and the substrate 2c of the latent image carrier 2.
_It must be set to be larger than _th .

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 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 the region where C is small, the surface potential of the latent image carrier 2 is the same as described above.
Constant voltage-(| V₀| -Discharge starting voltage V_th),
In a region where the capacitance C of the dielectric 2b is larger than a predetermined value, the latent image
The absolute value of the surface potential of the carrier 2 decreases. On the other hand,
It is assumed that the pole 3b is connected to the B side and the write electrode 3b is grounded.
Of the latent image carrier 2 and the surface potential of the latent image carrier 2
4 (d), the latent image carrier 2
In a region where the capacitance C of the latent image carrier 2 is small, the surface potential of the latent image
Constant ground voltage V₁And the capacity C of the latent image carrier 2 becomes
In a region larger than the predetermined value, the surface potential of the latent image
Absolute value rises.

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 voltage− (| V ₀ | −discharge start voltage V _th ), the latent image carrier 2 Discharge is performed between the adjacent writing electrode 3b and the charging layer 2d of the latent image carrier 2. That is, the latent image carrier 2 is
Is charged or neutralized. Note that the predetermined voltage V ₀ is (+)
The same applies to the case of the above voltage.

Therefore, the capacity C of the latent image carrier 2 is set to a small area where the surface potential of the latent image carrier 2 becomes a constant voltage− (| V ₀ | −discharge start voltage V _th ), and writing is performed. The voltage applied to the electrode 3b is a predetermined voltage V ₀ and a 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.

In this manner, the resistance R of the writing electrode 3b and the capacitance C of the latent image carrier 2 are set such that the surface potential of the latent image carrier 2 becomes a constant voltage, and applied to the writing electrode 3b. By performing switching control of the voltage between the predetermined voltage V ₀ and the ground voltage V ₁ , 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).

Next, the flexible substrate 3a that supports the writing electrode 3b of the writing device 3 will be described. As shown in FIG. 2 described above, the substrate 3a is composed of a flexible material having a relatively soft elastic, such as FPC or PET film, writing electrode 3b to the distal end portion 3a ₁ of the substrate 3a
Has been fixed. Then, as described later, the write electrode 3
Since the b is arranged in a plurality of rows in the axial direction (main scanning direction) of the latent image carrier 2, the substrate 3 a is arranged in the axial direction of the latent image carrier 2 in the It is formed in a rectangular plate shape having substantially the same length as the direction length. 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 base material 3a is provided so as to extend from the right side in FIG. 2 so as to face 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 deformed to generate a weak elastic restoring force, and the insulating layer 28 is lightly pressed on the latent image carrier 2 with a small pressing force by the elastic restoring force. Have been in contact. This small pressing force has a width of 3
Pressing force 10 N or less at 00 mm, ie, linear pressure 0.03 N
/ Mm or less stabilizes the proximity of the writing electrode 3b to the latent image carrier 2 (the gap between the writing electrode 3b and the latent image carrier 2),
It is preferable in terms of stabilizing discharge, and it is desirable to reduce the linear pressure as much as possible while maintaining a state in which the contact is kept stable from the viewpoint of wear. As described above, by making the insulating layer 28 the latent image carrier 2, the writing electrode 3 b and the charged layer 2 of the latent image carrier 2 are formed.
A predetermined gap (proximity distance) between them is fixed.

Further, since the pressing force of the insulating layer 28 against the latent image carrier 2 is small, abrasion of the charged layer 2d of the latent image carrier 2 by the insulating layer 28 is suppressed, and the durability is improved. In addition, since the insulating layer 28 is in contact with the charged layer 2d by the elastic force of the base material 3a, the writing electrode 3b comes to be stably close to 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 as will be described later is fixed.

As shown in FIG. 2, when the substrate 3a is provided so as to oppose the rotation direction of the latent image carrier 2, foreign matter adhering to the latent image carrier 2 is removed from the substrate 3a and the insulating material. Layer 2
8, the writing device 3 has a cleaning characteristic. When the substrate 3a is provided in the same direction as the rotation direction of the latent image carrier 2, the writing device 3 adheres to the latent image carrier 2. This makes it possible for foreign matter that has passed through between the insulating layer 28 and the latent image carrier 2.

FIG. 6 is a schematic view 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.

The axial direction of the latent image carrier 2 of the substrate 3a in this example
The length is also substantially equal to the axial length of the charging layer 2d of the latent image carrier 2.
The hair length of the base material 3a is set to the same length.
Curved part (bent part) 3a_ThreeIn place
The write electrodes 3b are fixed in a plurality of rows in the axial direction of the latent image carrier 2.
Have been. In the same manner as in the above-described example, the write
An insulating layer 28 is provided on the surface on the pole 3b fixed side. Soshi
As shown, both ends 3a of the base material 3a₁, 3a_TwoIs fixed
In this state, the hairpin curved portion 3a of the substrate 3a
_ThreeIs slightly bent elastically, and the hairpin
Curved part 3a_ThreeInsulation layer 28 is hidden by weak elastic restoring force
The image carrier 2 is lightly pressed and in contact with the image carrier 2. This example
In the writing device 3, the base material 3a is₁, 3a_TwoSupport
The insulating layer 28 is more secure than the previous example.
Real and more stable contact. FIG.
Then, both ends 3a of the base material 3a ₁, 3a_TwoEach electrode 3
b shows that the driver 11 is fixed.
However, this shows the arrangement pattern of the electrodes shown in FIG.
are doing.

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 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 perpendicular 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 manner, 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-mentioned non-charged portion or No non-static portion 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 writing electrode 3b is not limited to a triangle, but may be a trapezoid, for example.
One of the adjacent write electrodes 3b such as a parallelogram, a shape having an inclined side on at least a part of the opposite side of the adjacent write electrode 3b, or a shape having irregularities on the opposite side of the adjacent write electrode 3b. Any shape can be used as long as the portions overlap each other in a direction orthogonal to the axial direction of the latent image carrier 2. In this example as well, as in the example shown in FIG.
Are connected, and each driver 11 is arranged on the same side with respect to the electrode 3b.

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 that 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 the 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. As shown in FIG. 8, each driver 11 is formed on a base material 3a and has a conductive pattern formed of, for example, a copper (Cu) foil having a rectangular cross section and a thin flat plate shape (the cross section is shown in FIG. 11 described later). (Cu pattern) 9, and each driver 11 and each electrode 3 b are similarly electrically connected by the conductive pattern 9 formed on the base material 3 a. 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. The writing electrodes 3b adjacent to each other in the first and second columns are arranged so that some of them overlap each other 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 latent image carrier 2
No non-charging portion or non-static erasing portion as described above is not formed on the surface, 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 row are connected to one driver 11 are arranged, and a set in which a predetermined number of electrodes 3b in the second row are connected to one driver 11 is provided. There are multiple sets. 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.

Incidentally, also in the writing device 3'b, the base material 3'a supporting the writing electrode 3'b is the same as the base material 3a of the writing device 3.
The insulating layer 28 'is provided on the support surface of the writing electrode 3'b of the base material 3'a. Also, 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 directions of the trapezoids of the first row write electrodes 3b and the second row write electrodes 3'b are 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 functions and effects of these examples are the same as those of the example shown in FIG.

FIGS. 11A to 11C 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 portion with the latent image carrier 2 is shown facing downward, but these FIGS. 11 (a) to 11 (c) 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.
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 conductive material line 9a including the write electrode 3b in the example shown in FIG. 11A and the insulating layer 28 are provided with a protective layer 29 having lubricity. The protection layer 29 provided on the conductive material line 9a is a conductive material line 9a including the write electrode 3b.
Is prevented from being rusted by ozone when ozone O ₃ is generated. Further, the protective layer 29 provided on the insulating layer 28 prevents the abrasion of the insulating layer 28 due to the contact with the latent image carrier 2, so that the latent image carrier 2
A predetermined gap (close distance) with b is maintained.

In the writing device 3 of the example shown in FIG.
On the surface of the write electrode 3b of the conductive pattern 9 in the example shown in FIG. 11A described above, a large number of spherical fine particles 12 that allow foreign substances to pass through are provided in a rollable manner. 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. By providing the fine particles 12 also in the insulating layer 28, lubrication between the insulating layer 28 and the latent image carrier 2 can be improved.

FIG. 12 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. 12, for example, in 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. 13 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. 13 (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. For example, as shown in FIG.
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 13 (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. 3 (c) is obtained.

According to the image forming apparatus 1 using the writing device 3 configured as described above, the writing electrode 3b and the latent image carrier 2
The writing electrode 3b is provided close to the latent image carrier 2 so that a discharge is generated between the writing electrode 3b and the writing electrode 3b. Writing can be easily performed on the latent image carrier 2. In this case, since the write electrode 3b is supported by the flexible base material 3a, the gap between the write electrode 3b and the latent image carrier 2 can be set flexibly. Therefore, charging or discharging of the latent image carrier 2 by the writing electrode 3b can be performed more stably and with high accuracy. Thereby, the writing of the electrostatic latent image can be performed more stably, so that a good image can be obtained reliably and with high accuracy.

In particular, by bringing the insulating layer 28 provided on the base material 3a into contact with the latent image carrier 2, the gap between the writing electrode 3b and the latent image carrier 2 can be made more stable and more accurate. Can be set to Therefore, the write electrode 3b
Charging or static elimination can be performed more stably and with high accuracy.

Further, since the writing electrode 3b is close to the latent image carrier 2 by the flexible base material 3a, the writing electrode 3b
The spatial gap between the image and the latent image carrier 2 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 the writing electrode is only brought close to the latent image carrier, the latent image carrier 2
Can be prevented, 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.

Next, a specific example of an image forming apparatus using the writing apparatus 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. 14 schematically shows an example of an image forming apparatus using the writing device of the present invention, wherein 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. 14A is a monochrome image forming apparatus, and the 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. The insulating layer 28 provided on the substrate 3a
Is brought into contact with the surface of the latent image carrier 2 with a small pressing force due to the weak elastic restoring force of the substrate 3a, so that the writing electrode 3b fixed to the tip of the substrate 3a is exposed to the surface of the latent image carrier 2. Are close to 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, The latent image carrier 2 is charged or neutralized by each writing electrode 3b of the writing device 3, whereby 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 by a developer adhered to the latent image carrier 2 by a developing roller 4a of a developing device 4 which is not in contact with the latent image carrier 2 and then developed.
The upper developer image 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. 14B 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 constructed, 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 control device 7. After 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.

The 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. 15 is a diagram schematically showing another example of an image forming apparatus using the writing device of the present invention. As shown in FIG. 15, an 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 a latent image carrier 2. And a latent image carrier 2 in the form of an endless belt. 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 insulating layer 28_K, 28_Y, 28_M, 26_C
, As described above, lightly carry latent image with small pressing force
Contacting body 2. Therefore, each write electrode 3b_K, 3
b_Y, 3b_M, 3b_CIs a latent image carrier as described above.
It is close to 2. Although not shown, the image form of this example
Also in the forming apparatus 1, writing of the endless belt of the latent image carrier 2
Device 3_K, 3_Y, 3_M, 3_CIn the straight section opposite to
A carrier uniform charge control device 7 may be provided. Latent image carrier
When the charge control device 7 is not provided, the previous latent image is overwritten.
To form a latent image.
Since the load control device 7 is omitted, the number of parts can be reduced and the device can be reduced in size.
Type can be achieved.

[0077] 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. In this way,
Even in a full-color image forming apparatus in which developer images of each color are superimposed and color-matched on the latent image carrier 2, the writing device 3 of the present invention is used to make the configuration smaller and simpler. be able to.

FIG. 16 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. The insulating layers 28 _K , 28 _C , 28 _M , and 28 _Y provided on the respective base materials of the writing devices 3 _K , 3 _C , 3 _M , and 3 _{Y in} the same manner as described above,
By contacting the corresponding latent image carriers 2 _K , 2 _C , 2 _M , 2 _Y with a small pressing force, the write electrodes 3 b _K , 3 b _C , 3 are respectively provided.
b _M , 3b _Y are latent image carriers 2 _K , 2 _C , 2 _M ,
2 Close to _Y. Although not shown, each of the image forming apparatuses 1 _K , 1 _C , 1 _M , and 1 _Y has the same latent image carrier uniform charge control device 7 as described above for each of the writing devices 3 _K , 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. 17 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 of the first embodiment, as 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.
6 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. 18 is a view similar to FIG. 2, 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 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. An insulating layer 28 is interposed between the uniform charge control electrode 7e and the writing electrode 3b. Each of the writing electrode 3b and the uniform charge control electrode 7 has a weak elastic restoring force due to the bending of the base material 3a.
Is brought into contact with the surface of the latent image carrier 2 with a small pressing force, whereby the writing electrode 3b is brought close to the latent image carrier 2 and the uniform charge control electrode 7 is also placed at a predetermined close distance. It is close to the latent image carrier 2.

[0083] Postscript In 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 by charging or discharging the input electrode 3b. In the image forming apparatus 1 of this example, the uniform charge control electrode 7e
Since the image forming apparatus 1 and the writing electrode 3b are provided integrally, the image forming apparatus 1 can be formed more compact and simpler. Other configurations and other 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. 18 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. Further, the uniform charge control electrode 7e can be brought into light contact with the latent image carrier 2 by a restoring force due to the bending deformation of the base material 3a.

Further, in the example shown in FIG. 2, the insulating layer 28a on the tip side of the writing electrode 3b of the base material 3a may be omitted. Furthermore, by appropriately selecting the elastic modulus of the base material 3a, the shape of the base material 3a, or fixing the base material 3a, and bringing the writing electrode 3b close to the latent image carrier 2 by the base material 3a itself, the insulating layer 28 Can be omitted. Thereby, there is no possibility that unnecessary charge or discharge of unnecessary charges is caused by the contact of the insulating layer 28 with the latent image carrier 2, and it is possible to prevent a possibility that vertical streaks are generated in an image.

[0086]

As is apparent from the above description, according to the image forming apparatus of the present invention, the writing electrode is caused to generate a discharge between the writing electrode and the latent image carrier so as to carry the latent image. Since it is provided close to the body, the discharge allows the electrostatic latent image to be easily written on the latent image carrier by charging or discharging by the writing electrode. In this case, since the write electrode is supported by the flexible base material, the gap between the write electrode and the latent image carrier can be set flexibly. Therefore, the charging or discharging of the latent image carrier by the writing electrode can be performed more stably and with high accuracy. Thereby, the writing of the electrostatic latent image can be performed more stably, so that a good image can be obtained reliably and with high accuracy.

In particular, by bringing the insulating layer provided on the base into contact with the latent image carrier, the gap between the writing electrode and the latent image carrier can be set more stably and more accurately. Become. Therefore, charging or static elimination by the writing electrode can be performed even more stably and with high accuracy.

Further, since the writing electrode is brought close to the latent image carrier by the flexible base material, the spatial gap between the writing electrode and the latent image carrier can be extremely reduced. 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.

Further, since the writing electrode is merely brought close to the latent image carrier, it is possible to prevent the latent image carrier from being damaged by the writing electrode and to improve the durability of the latent image carrier. Also,
Even if the insulating layer is brought into contact with the latent image carrier, since the insulating layer is provided on the flexible base material, the pressing force of the insulating layer against the latent image carrier can be set very small, and the flexible Damage to the latent image carrier by the insulating layer can be suppressed. Further, since only a writing electrode is used as a writing device, a large-sized laser light generator, LED lamp light generator, and the like as in the related art can be eliminated. Therefore, the size of the apparatus can be further reduced, and the number of parts can be further reduced, so that a simpler and less expensive image forming apparatus can be obtained.

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

FIG. 3 is a diagram illustrating a basic process of image formation in the image forming apparatus of the present invention.

4A and 4B illustrate a principle of writing an electrostatic latent image by charging or discharging a writing electrode of a writing device, and FIG. 4A 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.

5A and 5B are diagrams for explaining charging or discharging of a latent image carrier, FIG. 5A is a diagram for explaining charging or discharging of the latent image carrier by charge injection, and FIG. FIG. 3C is a diagram for explaining Paschen's law.

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 11C are cross-sectional views illustrating examples of write electrodes of a writing device.

FIG. 12 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. 13 shows a state in which each high voltage switch of each electrode is selectively controlled to be switched to a predetermined voltage V0 or a ground voltage V1, respectively. FIG. 13 (a) 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.

14A and 14B schematically show an example of an image forming apparatus using the writing device of the present invention, wherein FIG. 14A is a diagram showing an image forming apparatus having a cleaner, and FIG. 1 is a diagram illustrating an image forming apparatus of FIG.

FIG. 15 is a diagram schematically showing another example of the image forming apparatus using the writing device of the present invention.

FIG. 16 is a view schematically showing still another example of the image forming apparatus using the writing device of the present invention.

FIG. 17 is a diagram schematically showing still another example of the image forming apparatus using the writing device of the present invention.

FIG. 18 is a view similar to FIG. 2, 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, 28: insulating layer, 29: protective 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 AE12 AE21 AE31 AE44 AE47 EA17 EA19 2H029 AA06 AB04 AC05 AD07

Claims (8)

[Claims] 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; 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 for supporting the writing electrode. An image forming apparatus, wherein the writing electrode and the latent image carrier are close to each other so as to generate a discharge. 2. An insulating layer is provided on the flexible base material, and the writing electrode is brought close to the latent image carrier by contacting the insulating layer with the latent image carrier. The image forming apparatus according to claim 1, wherein: 3. The image forming apparatus according to claim 1, wherein the writing electrode writes the electrostatic latent image on the latent image carrier by charging the latent image carrier. 4. The image forming apparatus according to claim 1, wherein the writing electrode writes the electrostatic latent image on the latent image carrier by removing charges from the latent image carrier. . 5. The writing electrode writes the electrostatic latent image on the latent image carrier by switching between a high voltage and a low voltage in accordance with an image to be formed. Item 5. The image forming apparatus according to item 3 or 4. 6. The writing device and the developing device,
Black, yellow, magenta, and cyan are provided for each color, and the developer images of the respective colors are formed by being superimposed on the latent image carrier by the writing device and the developing device of the respective colors. The image forming apparatus according to claim 1, wherein: 7. The image forming apparatus for each color of black, yellow, magenta and cyan is provided in tandem by providing the latent image carrier, the writing device and the developing device for each of black, yellow, magenta and cyan. The image forming apparatus according to claim 1, wherein: 8. The image forming apparatus according to claim 7, further comprising an intermediate transfer device for intermediately transferring a developer image for each color by the image forming device for each color.