JPH05241423A - Recorder - Google Patents

Abstract

PURPOSE:To excellently and surely perform electrification, to surely stir residual developer so as to prevent from being patterned and to obtain a clear image without generating harmful ozone by solving the uneven electrification of an electrifying and stirring means, environmental change, or problem that secular change in a mechanical friction coefficient is large in a cleanerless recorder. CONSTITUTION:A conductive contact 30 having a surface consisting of a low friction material whose surface is not uneven like a brush and which has smooth surface whose mechanical friction is not large like rubber is allowed to consecutively rub a photosensitive drum 3 functioning as an image carrier with relative friction, so that the photosensitive drum 3 is triboelectrified to the same polarity as the electrifying polarity for the drum 3, and the residual developer is stirred so as to prevent from being patterned.

Description

Detailed Description of the Invention

 [Object of the Invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording device such as an electrophotographic device or an electrostatic printer, and more particularly to a cleanerless recording device having no cleaning means.

[0002]

2. Description of the Related Art In a recording apparatus of this type, a photosensitive drum, which is generally an image carrier, is corona charged to form an electrostatic latent image, and then a developer is electrostatically attached to the electrostatic latent image. Thus, a developer image is formed, and subsequently, the developer image is transferred onto a sheet, which is a material to be transferred, for recording. Also,
After the transfer, the electrostatic latent image and the developer that cannot be completely transferred remain on the photoconductor after transfer, so the remaining developer is removed by a cleaning device, and then the electrostatic latent image is removed by a static eliminator. ing.

By the way, in recent years, it has been pointed out that ozone discharged from a recording apparatus of this kind is harmful. These are all generated from a corona discharge device used in a charging device or a transfer device, and in order to remove them, a means such as collecting with an activated carbon filter has been sought. However, this filter has to be replaced on a regular basis, which has both a cost problem and a troublesome problem.

Therefore, as a feature that ozone is generated very little and a collecting means is not necessary, so-called contact charging means for charging a conductive member by contacting it with an object to be charged has been developed and extensively studied for improvement. Has been done in.

As this contact charging means, Japanese Patent Laid-Open No. 57-
As described in Japanese Patent No. 185455, there are one that charges by applying a voltage while slidingly contacting a conductive brush, and one that charges a dielectric such as a photoconductor by applying a voltage while rollingly contacting a conductive roller. Mainly known.

Although these charging means have been known in the past, the reason why they have not been put into practical use is that the method using a brush has little change over time, but the drawback that the streaks of the brush appear as uneven charging in the image has not been solved. There is something that can be done.

Further, while roller-shaped ones are less likely to cause streak-like unevenness, they have a large change over time, and since a conductive rubber is used as a material, the friction coefficient is, for example, urethane rubber to hard steel. Dynamic friction coefficient is 0.8 ~
It has a drawback that it is difficult to provide a cleaning means as large as 1.3.

Further, since the mechanical friction coefficient is large, the friction with an object to be charged such as a photoconductor also becomes large. Therefore, it is devised to make the uneven charging by sliding contact (having a relative speed difference). There was no room. For this reason, in the case of brush charging, although charging is generally performed while making sliding contact, roller charging must be used without giving a relative speed difference. As a result, the conventional contact charging means cannot be used in a device requiring high image quality such as corona charging because of poor uniform charging property. In addition, there is a problem in that the electric resistance is unstable with respect to environmental changes such as humidity and the use conditions are largely restricted.

On the other hand, in recent years, miniaturization of devices has been strongly demanded. On the other hand, for example, a recording device has been proposed in which one device serves as both the developing device and the cleaning device, and further, the disturbance of the transfer residual toner image and the charging process can be simultaneously performed by the same means. There is. As a result, it is possible to realize a recording apparatus that is small in size, has no waste toner, and generates little ozone.

This method is generally referred to as a cleanerless system, in which the electrostatic latent image is developed by the one developing device during the first passage of the electrostatic latent image and the development remaining after the transfer. The cleaning with the agent is done at the same time.
It solves the drawbacks of the single-rotation type cleanerless device in terms of speed and size.

However, in this conventional method, while the residual toner image after transfer is left on the photosensitive drum, the disturbance (non-patterning) and charging of the residual toner are simultaneously caused by the brush-shaped conductive contact. To do.

Therefore, it is possible to achieve both sufficient disturbance (non-patterning) of the toner image remaining after transfer and charging by uniform contact charging by only passing the brush-shaped conductive contact portion once. It was quite difficult, and there was a drawback in that toner scattering and memory images (afterimages) often appeared on the next screen and the fidelity and quality of the images were impaired.

[0013]

As described above, the charging disturbing means in the conventional cleanerless recording apparatus has a great feature that the harmful ozone is very little generated and the collecting means is unnecessary, but the charging unevenness is large. Was large, the environmental change was large, or the mechanical friction coefficient was large and the change over time was large.

The present invention has been made in view of the above circumstances, and is a drawback of the charging disturbing means in the conventional cleanerless recording apparatus. The charging unevenness is large, the environmental change is large, or the mechanical friction coefficient is large. By solving the problem of large changes over time, good and reliable charging can be performed, and residual developer can be reliably disturbed and unpatterned, and clear images can be obtained without generating harmful ozone. It is an object of the present invention to provide a cleanerless recording device capable of performing. [Constitution of Invention]

[0015]

The present invention provides, as a first means for solving the above problems, an image bearing member carrying an image, and a latent image forming for forming an electrostatic latent image on the image bearing member. Means, developing cleaning means for supplying a developer to the electrostatic latent image formed by the latent image forming means to develop the electrostatic latent image, and at the same time removing the developer remaining on the image bearing member, and the developing cleaning means. A transfer unit configured to transfer the developer image formed on the image carrier to a transfer target material; and a conductive contact having a surface that continuously rubs the image carrier with relative friction, After the transfer of the developer image by the transfer means,
By applying a voltage to the conductive contact and rubbing the image carrier so as to cause relative friction, the transfer residual toner remaining on the image carrier after the transfer is disturbed and the image carrier is predetermined. And a charging disturbing unit that is charged with the polarity.

As the second means, the surface layer which continuously rubs with the image carrier of the conductive contact of the charging disturbing means in the first means by relative friction is made of a fluorine-containing resin. It is a thing.

[0017]

According to the cleanerless recording apparatus of the first means, the conductive contact of the charging disturbing means has a surface which continuously rubs against the image carrier with relative friction, Rubbing the image carrier to frictionally charge the image carrier to the same polarity as the charging polarity of the image carrier. As a result, it is possible to eliminate microscopic unevenness by preventing frictional charging in the opposite charging direction,
In addition to macro charging by voltage application, it is possible to improve triboelectrification of a predetermined polarity. In addition, a conductive elastic member made of a low friction material having a smooth surface, which is not uneven like a brush and has a small mechanical friction like rubber, can be used as a charging contactor, and a large sliding surface can be used. Since it can make sliding contact with the image carrier without using contact force,
More uniform charging is possible. As a result, good and reliable charging can be performed without generating harmful ozone, and a clear image can be obtained.

Further, since the low-friction contactor has a relative speed difference and is easily slidably contacted, it exerts an effect of uniformly spreading the residual toner, so that it is disturbed at the same time as charging without scattering like a brush. Will be easier to do.

Further, according to the cleanerless recording apparatus by the second means, in addition to the function of the first means, since the fluorine-containing resin is used for the surface layer of the contact, the hydrophobicity is good and the humidity is high. Compared with the conventional conductive material, it has extremely good stability against changes and enables better charging.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows the structure of a recording apparatus 1 of the present invention, and FIG. 2 shows the structure of the main part thereof.

As shown in FIG. 1, a photosensitive drum 3 as an image carrier having a diameter such that the circumferential surface length is smaller than the length of an image to be recorded is provided in the substantially central portion of the recording apparatus main body 2. It is rotatably provided at 65 mm / sec in the direction of arrow A. The photoconductor drum 3 is made of an organic photoconductor (OPC) photoconductive material.

Further, as shown in FIG. 2, around the photosensitive drum 3, the charging disturbing device 4 as the charging disturbing means and the L as the electrostatic latent image forming means are sequentially arranged along the rotation direction thereof.
An ED exposure device 5, a developing / cleaning device 6 as a developing / cleaning unit, and a transfer roller 7 as a transferring unit are provided. A recording unit 10 that records a toner image TI as a developer image on the peripheral surface of the photosensitive drum 3 is configured.

Further, in the apparatus main body 2, a sheet P as a transfer target material taken out from a paper feed cassette 11 mounted on one side of the apparatus main body 2 and the photosensitive drum 3 of the recording means 10 are provided. A sheet conveyance path 14 is formed as a transfer material conveyance path that leads to a sheet discharge tray 13 disposed on the other side of the apparatus main body 2 via an image transfer section 12 between the transfer roller 7 and the transfer roller 7.

The image transfer section 12 of the sheet conveying path 14
The upstream side of the sheet feed cassette 1 via the sheet feed roller 15.
An aligning roller pair 16 is arranged to feed the paper P taken out from No. 1 to the image transfer unit 12 at a timing after the paper P is aligned.

On the downstream side of the image transfer section 12,
A fixing device 1 for fixing the toner image TI transferred onto the paper P
A paper discharge roller pair 18 for discharging the paper 7 and the fixed paper P to the paper discharge tray 13 is provided.

Further, the fixing device 17 and the pair of discharge rollers 18
A gate 20 for guiding the paper P fixed by the fixing device 17 to the reversal conveyance path 19 is provided between the and. The paper P guided to the reverse conveyance path 19 has a pair of paper ejection rollers 2
The sheet is ejected to the sheet ejection section 22 formed of a recess formed on the upper surface side of the apparatus main body 2 with the image forming surface facing downward. Next, the configuration of the charge disturbing device 4 as the charge disturbing means, which is the main part of the present invention, will be described in detail with reference to FIGS. 2 and 3. The charging disturbance device 4 is
As shown in FIG. 2, a roller-shaped contactor 30 as a conductive contactor and a protective cover 31 surrounding the outer periphery of the contactor 30.

As shown in FIG. 2, the contactor 30 has an elastic rubber layer 30B formed on the outer periphery of a metal shaft 30A,
Furthermore, 10 ⁴ is formed on the surface of the elastic rubber layer 30B. -10 ¹⁰ Ω
It has a roller shape of the surface layer 2C having an electric resistance of cm.

A conductive fluorine-containing resin is used for the surface layer 30C. This conductive fluorine-containing resin, for example, polyvinylidene fluoride, vinylidene fluoride copolymer and at least one or more thermoplastic resin containing fluorine selected from ethylene tetrafluoroethylene, etc. A conductive material such as ether ester amide or polyether amide is added in an amount of 2 to 20% by weight based on the fluororesin and melt-kneaded to produce 10 ⁴ A fluororesin having an electric resistance of -10 ¹⁰ Ω · cm is obtained. Then, this resin is formed into a tubular film having a thickness of 10 to 60 microns by a molding means such as an extrusion molding method.

Other methods for producing such a fluorine-containing resin are known. In addition to the technique of making these resins conductive, a method of kneading a conductive filler such as carbon is also known.

The elastic rubber layer 30B is preferably 10 ⁸ As an elastic member having an electric resistance (conductivity) of Ω · cm or less, conductive urethane in which conductive carbon is dispersed, or elastic rubber made of foamed urethane, silicon or the like is attached to the outer periphery of the metal shaft 30A in a mold. It is supposed to be molded.

By thus fitting the surface layer 30C made of the tubular film to the outer periphery of the elastic rubber roller 30D made of the metal shaft 30A and the elastic rubber layer 30B, the roller-shaped contact 30 is formed. To get

The contactor 30 having such a structure is in sliding contact with the photosensitive drum 3 at a speed of 1 to 5 times (preferably 2 times or more) the peripheral speed of the photosensitive drum 3 and has a weight of about 20 to 200 g / cm. It is pressed against the photosensitive drum 3 by line weighting.

Further, the contact 30 includes a bias power source 32.
The peak-to-peak voltage biased by a DC voltage component of about 0 to 700 volts is 800
~ 2000 volts, frequency 0.1-5 kilohertz (KH
z) elastic rubber layer 30B which is a conductive support for the AC voltage
It is designed to be applied to. In this case, since the charging has a converging action, the DC voltage is set to a value substantially the same as the desired charging voltage of the photosensitive drum 3. However, this applied voltage can be charged with only the DC component. In this case, the voltage requires a high voltage of 1000 to 2000 volts. This value is empirically selected according to the actual situation.

The contact 30 is rubbed against the photosensitive drum 3 to erase the electrostatic latent image remaining in the previous step, if any, and to make the surface of the photosensitive drum 3 about +0. A negative charge of approximately 700 V is applied substantially uniformly.

At this time, the contact 30 has its surface layer 30C separated from the charging action by the discharge due to the applied voltage.
The surface of the photoconductor drum 3 is positively triboelectrically charged by exhibiting a strong triboelectric charging property peculiar to the fluororesin, which is the material.

Therefore, the streak-like unevenness due to the contact, which is easily caused by the conventional contact charging, which is caused by the cancellation of the charging due to the discharge and the charging due to the friction, is prevented, and the uniform charging is achieved. Combined with low friction, which is one of the features, uniform contact and rubbing with smaller torque are possible.

By the way, according to comparison of various surface materials by HEIDON (trademark) -14 type surface property tester (Shinto Kagaku Co., Ltd.), in a general conductive silicone roller and urethane rubber roller, a dynamic friction coefficient ( It was confirmed that the friction coefficient of the polyvinylidene fluoride roller used in the present invention was significantly reduced to 0.6 to 0.8, while the friction coefficient against the steel sheet was 1.2 to 1.5. Was done.

When the rotating contactor is used, the effect of this rubbing tends to improve the uniformity as the number of revolutions increases. It can be set to about 2 to 5 times the peripheral speed. The rotation direction is preferably the same rotation direction on the contact surface portion in consideration of the scattering of the toner T which is the developer, but there is no particular reason for limitation. In the dynamic friction coefficient measurement using a surface property tester (trade name) of Haydon (trademark), the friction coefficient of the used fluororesin (polyvinylidene fluoride) with respect to the aluminum plate is about 30 to 70% smaller than that of the urethane resin. The result was obtained. A predetermined voltage is applied to the roller contact 30 from a bias power supply 32.

In the cleanerless process, when the residual toner T is present on the photosensitive drum 3, the residual toner T is also mechanically actuated by the roller-shaped contact 30 and is discharged (charged). The contact condition and the voltage condition are set so as to exert the action of disturbing and scattering on the photosensitive drum 3. This is because the pressing force of the roller contact 30 is slightly larger than 30 to 120 g / cm ^2. The DC bias is set to about 400 to 1000 V (this value is almost the same as the charging voltage of the photoconductor drum 3 which is finally necessary. The charging voltage is mainly determined by the magnitude of this voltage. Adjust the DC voltage), and the peak-to-peak voltage is 800 to 20
By applying an AC voltage of 00 V and a frequency of 0.1 to 5 kilohertz (KHz) to the surface layer 30C through the elastic rubber layer 30B as a conductive support, the photosensitive drum 3 is charged or the residual toner T is discharged. It is possible to simultaneously perform both the disturbance and the charging of.

The roller contact 30 thus charges the surface of the photosensitive drum 3 to 0 to +700 V and disturbs the residual toner T on the photosensitive drum 3. Further, the contact 30 has little change in electric resistance with respect to changes in humidity, and with respect to changes in relative humidity from 30% to 85%,
The change was within two digits.

On the other hand, the electric resistance of the urethane type conductive roller made by the conventional carbon dispersion method changes by about three digits. This is in agreement with the result that the one adopted in the present application is excellent in terms of stability of the charging voltage with respect to a constant applied voltage. The height of this charging potential is adjusted according to the voltage condition described above, but more specifically, the applied voltage is actually determined in consideration of the history image erasing (memory erasing) condition caused by the disturbance effect of the residual image described later. To be done.

As described above, the contact 30 is brought into sliding contact with the rotation of the photosensitive drum 3, is connected to the bias power source 32, and is applied with the voltage of the above-mentioned condition, so that the transfer residual toner T on the photosensitive drum 3 is applied. Is disturbed by mechanical and electrostatic adsorption and repulsion to make it unreadable, i.e., it has a non-patterned but smooth surface, so that scratch-like streaks do not occur. Further, the remaining electrostatic latent image is neutralized or charged by the action of the conductive surface layer 30C to eliminate the potential unevenness, and the surface material is selected so that the triboelectrification property is also the same as the charging polarity. Therefore, it is possible to more uniformly and uniformly charge.

This is because a voltage sufficient to generate discharge is applied to the photosensitive drum 3 by the applied voltage, and the discharge causes the photosensitive drum 3 to have a plus voltage of 500-500.
It is charged to 700 volts. The voltage application to the contact 30 is independent of the charging of the photosensitive drum 3 and the residual toner T
Is electrostatically adsorbed temporarily, and at the next moment, Toner-T
Is applied to the photosensitive drum 3 again. This is because the adsorbed toner T is charged to the same polarity as the charging polarity by the next momentary discharge, so that it changes into a repulsive force. As a result, the residual toner T on the photosensitive drum 3 is
The residual toner T can be electrostatically disturbed to be non-patterned without being accumulated in the contactor 30, and the photosensitive drum 3 can be charged.

FIG. 4 shows an example of measurement of the charging characteristic of the photosensitive drum 3 with respect to the voltage condition applied to the contact 30. In FIG. 4, the vertical axis represents the charging potential of the photosensitive drum 3, and the horizontal axis represents the DC component (biased component) of the applied voltage.

In FIG. 4, (a) is alternating current (AC) 2 kilohertz (KHz), voltage (P-P) 1.5 kilovolt (KV)
And what. (B) is for a voltage of 1 KV.
(C) is the charging characteristic when there is no AC component.

Even if no AC component is applied, the uneven charging is small and no trace of being rubbed by a brush is generated in the halftone of the image, which is an effect of improving the triboelectricity of the surface material used in the present application. .. When an AC voltage of about 1 KV or more is applied, charging unevenness is further reduced. From FIG. 4, for example, it can be seen that the biased component may be 500 to 550 volts under the condition (a) in order to charge +500 volts as in this embodiment.

In FIG. 5, the degree of occurrence of image history (memory image) appearing on the image when various voltages applied to the surface layer 30C are changed under the charging condition of the contact 30 is shown by the sensory evaluation. It is expressed in arbitrary units, and it means that the memory goes down as going down and the memory goes up as going up. The bias voltage applied to the developing roller 35 is plus 200 volts. Here, the voltage condition applied to the contact 30 is that when an AC voltage of 1 kHz is applied (effective value) with a positive DC voltage as a horizontal axis parameter. From this result, it can be seen that the charge range becomes good in the charge range above 500 V which is a practical charge potential. Next, the configuration of other main means will be described with reference to FIGS. 1 and 2 again.

The LED exposure device 5 as the electrostatic latent image forming means irradiates the surface of the photosensitive drum 3 with the LED light R in accordance with the image information to be recorded to form an electrostatic latent image on the charged area. To do.

Further, the developing / cleaning device 6 as the developing / cleaning means has a developing roller 35 arranged so as to face the photosensitive drum 3. The developing roller 35 rotates to accommodate a toner T (volume average particle diameter, 6 to 15 microns) as a triboelectric so-called one-component developer housed in a hopper 36 on the photosensitive drum 3. It is configured to be continuously conveyed toward the development-development cleaning position facing the. Then, the electrostatic latent image formed on the photoconductor drum 3 is developed, and the transfer residual toner T remaining on the photoconductor drum 3 is collected and returned into the hopper 36.

The developing roller 35 is 10 ² ~ 10 ⁸ Ω
・ Has a conductive surface layer with cm electrical resistance, urethane or silicon rubber, diene rubber (EPDM, etc.)
Conductive filler (conductive carbon, metal powder, etc.)
It is made up of dispersed objects. The surface of the developing roller 35 needs to carry materials and additives in consideration of the toner T and triboelectric charging, and in consideration of appropriate elasticity and friction. As the material of the surface layer of the developing roller 35,
For example, 10 to 30 conductive carbon is added to urethane resin.
It may be formed by applying a mixture of weight percentages. Further, a predetermined developing bias is applied to the developing roller 35 from a bias power source 40 at the time of developing and cleaning.

An elastic blade 37 for forming a thin layer while frictionally charging the toner T is pressed against the developing roller 35, and the toner T passing therethrough has the same polarity as the photosensitive drum 3. 1 to 3 layers (6 to 4) with negative triboelectrification
Toner layer (5 microns thick) is formed. Elastic blade 3
7 is made of phosphor bronze, urethane, silicon resin, or a composite of these.

On the other hand, in the hopper 36, a sponge-shaped toner conveying roller 41 is provided, which prevents the toner T in the hopper 36 from agglomerating, conveys and supplies it, and further, the toner T on the developing roller 35. It plays the role of scraping.

The transfer roller 7 serving as the transfer means is provided below the photosensitive drum 3 substantially with the paper conveying path 14
It is provided so as to face the peripheral surface of the photoconductor drum 3 via. The transfer roller 7 has a structure similar to that of the developing roller 35, but the electric resistance of the surface layer is 10 ⁵ It is on the high resistance side at -10 ¹⁰ Ω · cm.

The transfer roller 7 applies a voltage of plus 800 to 2200 V to the back surface of the sheet P conveyed here to electrostatically attract the toner image TI, and the toner image TI is removed from the photosensitive drum 3. Transfer the image TI to the paper P. Since such a contact type transfer means exerts stable transfer characteristics even under high humidity, it has an effect of reducing the amount of residual transfer toner and reducing the cleaning load, and at the same time, the paper P
It also has an action of removing the paper dust inside, and prevents the development cleaning device 6 from being mixed. Next, the operation of the recording apparatus according to this embodiment will be described.

Rotate the photosensitive drum 3 in the direction of arrow A,
The peripheral surface of the photosensitive drum 3 is covered with a roller-shaped contactor 30.
It is charged to about +500 to 800 volts. Subsequently, the charged area is irradiated with LED light R from the LED exposure device 5 to be exposed to form an electrostatic latent image on the surface of the photosensitive drum 3. The electrostatic latent image is then conveyed to a developing / cleaning position facing the developing / cleaning device 6. Here, elastically to the electrostatic latent image, and
Due to the deformation, the developing roller 35 comes into contact with the nip width,
The toner image TI is formed by being developed by the toner T conveyed by the developing roller 35.

In this case, the toner T is what is called reversal development that adheres to the irradiation area of the LED light R. The toner T is charged to about +5 to 30 μc / g (microcoulomb / gram) by friction with the elastic blade 37 and the surface layer of the developing roller 35, and the developing roller 35 has about +100.
A voltage of ~ 400 volts is applied. The most preferred voltage is + 150-300 volts.

The developed toner image TI is then conveyed to a transfer area facing the transfer roller 7. On the other hand, the paper P taken out from the paper feed cassette 11 by the rotation of the paper feed roller 15 is sent to the transfer area in synchronization with the rotation of the photosensitive drum 3. The rear surface of the paper P is charged to a positive polarity by the transfer roller 7. Therefore, the toner image TI on the surface of the photoconductor drum 3 is electrostatically attracted to the paper P and transferred.

Here, the transfer roller 7 is a DC power source 4
2, a voltage of -1000 to 2000 V is applied to the rotary shaft, and the roller surface is transferred through a conductive portion formed by mixing conductive carbon with silicon resin provided at both ends of the transfer roller 7 in an amount of 30 to 40 wt%. Of 10 ⁵ -10 ⁹ Ω
A voltage is applied to the conductive surface portion of cm. The surface of the transfer roller 7 is cleaned by a cleaning blade 43 to clean foreign matter such as toner and paper dust.
To be cleaned. The rubber hardness of the roller as a whole is 25 ° to 50 ° which is flexible in the comparative measurement of JIS method, and the tolerance of the pressing force of the transfer roller 7 to the photosensitive drum 3 is good.

The sheet P on which the toner image TI has been transferred is sent to the fixing device 17, where the toner image TI is fused and fixed on the sheet P, and thereafter, the sheet discharge tray 13 or the sheet discharge section 22.
It is discharged according to the selected mode.

Here, on the surface of the photosensitive drum 3 after the transfer, the toner T slightly left untransferred or the positive and negative electrostatic latent images left after the toner transfer remains. ..

The remaining toner T or electrostatic latent image is then conveyed to the contact 30 and disturbed or unpatterned as described in detail above, and the electrostatic latent image formed by image exposure in the next step is carried out. Charging for latent image formation is performed. The contactor 30 is brought into contact with the photosensitive drum 3 so as to cause relative friction on the electrostatic latent image, and exerts mechanical electrostatic force to finely remain the toner T which remains unreadable. The toner T is disturbed by the electrostatic latent image and is discharged from the contactor 30 due to the applied voltage, so that the toner T is scattered on the surface of the photosensitive drum 3 and adheres thereto. Does not accumulate.

This is because the surface layer 30C of the contact 30 is made of a material having a small mechanical friction and has releasability, and the surface is smooth due to the fluorine-containing resin having a strong action of positively charging the toner T. Since it is formed in a state, it does not scrape off the residual toner T on the photoconductor drum 3 and has an action of frictionally charging the toner T and the photoconductor drum 3 to a predetermined polarity when rubbing. The uniform charging is realized in cooperation with the charging by the voltage applied to 30. That is, the contact 30 does not have a function as a cleaning device, but has a function of disturbing the residual image and charging the photoconductor drum 3 to the last.

As described above, the toner T scattered on the surface of the photoconductor drum 3 is distributed in a sufficiently small fog or droplet form and no longer has information as characters or images. Photoconductor drum 3 charged at the same time as the disturbance
After being charged, is exposed by the LED exposure device 5 to form an electrostatic latent image, and again reaches the developing and cleaning position facing the developing and cleaning device 6 (second recording operation). In this case, the second
In the electrostatic latent image formed for the second time, the residual toner is greatly reduced by the image transfer process even in the exposed portion (the image portion to which the toner should adhere) or the non-exposed portion (the non-image portion). Since the residual toner T is dispersed substantially uniformly and sufficiently thinly, the LED light R is sufficiently diffused.
And exposure unevenness does not occur. Therefore, even in the case of the second development, the residual potential after exposure becomes uniform, so that a uniform development result can be obtained.

The developing roller 35 has elasticity of 20 to 60 ° according to the JIS rubber hardness measuring method and has a elasticity of 10 ² ~ 1
0 ⁸ 10 to 150 g / cm ² as a linear load on the developing roller 35 due to its conductivity. By applying a load of 1 to 4 and pressingly slidingly contacting each other with a speed difference of 1 to 4 times, a contact width (nip) of 1 to 4 mm is generated. At this nip, the residual toner T and the toner T on the developing roller 35 are However, since it is disturbed and rubbed, a strong frictional force is generated between the residual image and the cleaning ability. In addition, since the developer is formed only by the toner T, there is no occurrence of streak-like or square-shaped image quality deterioration. Further, in the non-exposed portion, the toner T that has adhered because the attraction force due to the developing bias exceeds that of the photosensitive drum 3 is successively attracted to the developing and cleaning device 6 and collected.

That is, by applying a developing bias having an appropriate value between the residual potential of the exposed portion and the potential of the non-exposed portion to the developing roller 35, new toner is supplied to the exposed portion from the developing roller 35. The residual toner T, which is attached to the non-image area (non-image portion) at the same time as T is attached, is attracted (that is, cleaned) from the developing roller 35 and collected therefrom.

In this manner, the photosensitive drum 3 is rotated in an overlapping manner to be used repeatedly, and one recorded image is obtained. Then, after development and cleaning, the toner image TI is transferred to the paper P at a position facing the transfer roller 7. Hereinafter, similar steps are repeated.

As can be seen from the above, according to this embodiment, even if the photosensitive drum 3 having a small diameter is used, not only the occurrence of a memory image which has been conventionally generated is eliminated but also cleaning failure is prevented. be able to. In this embodiment, when 20,000 sheets were printed using A4 size paper with an image area ratio of about 6%, good images could be obtained to the end without cleaning failure or memory abnormality. ..

Further, by adjusting the bias voltage applied to the contactor 30, it is possible to adjust not only the charging potential but also the disturbance effect of the toner T and the recovery and release state of the toner T so as to be actively controlled. it can. That is,
It is possible to prevent one-sided accumulation of the toner T on the contact 30. In this case, the bias voltage applied to the contactor 30 during the non-printing operation of the recording apparatus, that is, when the non-image area passes through the contactor 30, has a polarity of about −10, which is opposite to the polarity during developing cleaning.
The toner T adhered to or accumulated on the contact 30 is forcibly discharged to the photosensitive drum 3 with a voltage of 0 to 300 V, and then the toner T is conveyed to the developing / cleaning device 6 to collect the toner T. The dirt of 30 can be further reduced.

Further, when the ozone concentration in the exhaust part of the tester was measured, it was not detected below the measurement sensitivity. On the other hand, in a recording device having a general corona charging device,
It is known that the ozone emission concentration is 0.1 to 0.5 PPM when no reducing means such as an activated carbon filter is taken.

Further, in this embodiment, the photosensitive drum 3
Since the charging disturbing device 4 using the fluorine-containing conductive resin is used as the charging disturbing means, uniform charging without streaks due to uneven frictional charging can be achieved with a smaller friction torque. Further, as compared with the conventional charging method in which the rotating contact is made at a constant speed, the use of the low friction material in the present invention facilitates the charging while causing the relative friction with the photoconductor drum 3. The photosensitive drum 3, which is the object to be charged, has a characteristic that uniform charging can be obtained even if there is some unevenness. As described above, the charging disturbing device 4 of the present invention has much superior charging performance as compared with the conventional contact charger.

From the above, the charging disturbance device 4 of the present invention
It has been confirmed that, while having an ozone reduction effect far superior to that of the corona charger, it also exhibits an excellent function as a charging disturbance device comparable to that of the corona charger.

In the above-described embodiment, the roller disturbing device 30 is used as the charging disturbing device 4, but the charging disturbing device 4 is not limited to this and may be a fixed contactor. For example, it may be a blade-shaped contactor 300 as shown in FIGS.

This contact 300 has a shape similar to a cleaning blade used in an electrophotographic apparatus,
A surface layer 300B made of the same fluororesin as that used for the surface layer 30C of the roller-shaped contact 30 is formed on the surface of a core material 300A made of a urethane blade.

Then, the blade-shaped contact 300
As shown in FIG. 5, is mounted in a tilted state in the protective cover 301 via a holder 300C, and one sided abdomen thereof contacts the photosensitive drum 3. The contact pressure is about 10 to 50 g / cm 2. Even in this case, the same effect can be exhibited under exactly the same conditions for the magnitude and type of the applied voltage. As the contactor used in the charge disturbing device 4, in addition to the roller shape and the blade shape as described above, a foamed material or a simple plate-shaped material can be used.

The point is that the conductive contact has a surface that continuously rubs against the image carrier such as the photosensitive drum 3 with relative friction, and the image carrier is rubbed with the image carrier. Any material may be used as long as it is frictionally charged to the same polarity as the charging polarity of the image carrier.

Further, although the non-magnetic one-component developing system is used as the developing / cleaning device 6, the developing / cleaning device 6 is not limited to this. Needless to say, it can be realized by using other known magnetic one-component brush method, fur brush method, cascade method and the like. In addition, it goes without saying that the present invention can be variously modified and implemented within the scope of the invention.

[0077]

As described above, according to the present invention,
It has the following effects.

According to the recording apparatus of the first aspect, the conductive contact of the charging disturbing means has a surface that continuously rubs against the image carrier with relative friction, and by the rubbing with the image carrier. By making the image carrier frictionally charged to the same polarity as the charging polarity of the image carrier, it is possible to eliminate microscopic unevenness by preventing frictional charging in the opposite charging direction, and to make macro charging by voltage application. In addition, the triboelectrification property of a predetermined polarity can be improved. In addition, a conductive elastic member made of a low friction material having a smooth surface, which is not uneven like a brush and has a small mechanical friction like rubber, can be used as a charging contactor, and a large sliding surface can be used. It is possible to make sliding contact with the image carrier without using contact force. For this reason, more uniform charging is possible, the developer remaining on the image carrier can be disturbed to be non-patterned, and the cleaning efficiency of the residual developer can be improved. Therefore, it is possible to obtain a clear image without generating harmful ozone in a cleanerless recording device that can be made significantly smaller without separately requiring a charging device and a cleaning device. Become.

According to the recording apparatus of the second aspect,
In addition to the above effects, since a fluorine-containing resin is used for the surface layer of the contactor, it has good hydrophobicity and extremely good stability against humidity change compared to conventional conductive materials In addition to being able to be charged, it is possible to perform functional disturbance by taking advantage of the characteristics of the conductive fluorine resin, so that uneven exposure can be prevented and a clear image can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a recording apparatus of the present invention.

FIG. 2 is a partially enlarged view of FIG.

3 is a perspective view showing a cross section of a part of a roller contact of the charging disturbing device shown in FIG.

FIG. 4 is an explanatory diagram showing a measurement example of a charging characteristic of a photosensitive drum with respect to a voltage condition applied to a contact.

FIG. 5 is an explanatory diagram showing memory image erasing conditions.

FIG. 6 is a view showing another embodiment of the charge disturbing device.

7 is a partially enlarged view of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Recording device, 3 ... Photosensitive drum (image bearing member), 4 ... Charging disturbing device (charging disturbing means), 5 ... LED exposure device (electrostatic latent image forming means), 6 ... Development cleaning device (developing cleaning means) ), 7 ... Transfer roller (transfer means), 30 ... Roller-shaped contactor (conductive contactor), 30A ... Metal shaft, 30B
... elastic rubber layer, 30C ... surface layer, 30D ... elastic rubber roller, 31 ... protective cover, 32 ... bias power source, 300 ...
Blade-shaped contactor, 300A ... Core material, 300B ... Surface layer, 300C ... Holder, 301 ... Protective cover, P ... Paper (transferred material), T ... Toner (developer), TI ... Toner image (Developer image).

Claims (2)

[Claims] 1. An image carrier for carrying an image, a latent image forming means for forming an electrostatic latent image on the image carrier, and a developer for the electrostatic latent image formed by the latent image forming means. And a developing cleaning means for simultaneously removing the developer remaining on the image carrier, and a developer image on the image carrier formed by the developing and cleaning means is transferred to a transfer material. And a conductive contact having a surface that continuously rubs against the image carrier with relative friction, and a voltage is applied to the conductive contact after the transfer of the developer image by the transfer unit. At the same time, by rubbing the image carrier so as to cause relative friction, a charging disturbing unit that disturbs the transfer residual toner remaining on the image carrier after the transfer and charges the image carrier to a predetermined polarity, A record characterized by comprising Location. 2. An image carrier for carrying an image, a latent image forming means for forming an electrostatic latent image on the image carrier, and a developer for the electrostatic latent image formed by the latent image forming means. And a developing cleaning means for simultaneously removing the developer remaining on the image carrier, and a developer image on the image carrier formed by the developing and cleaning means is transferred to a transfer material. And a conductive contact having at least a surface layer having a surface made of a fluorine-containing resin that continuously rubs against the image carrier with relative friction, and after the transfer of the developer image by the transfer unit, By applying a voltage to the conductive contact and rubbing the image carrier so as to cause relative friction, the transfer residual toner remaining on the image carrier after the transfer is disturbed and the image carrier is moved to a predetermined position. Charge disturbing means charged to polarity ,
A recording apparatus comprising: