JPH0916021A - Image forming device - Google Patents

Abstract

PURPOSE: To prevent an adhering matter from being accumulated on the surface of a photoreceptor and to stably obtain an image over a long term by providing a control means controlling the operation of a supplying means and a removing means for supplying and removing a coating agent every specified time. CONSTITUTION: A coating agent supplying means 10 is arranged on the downstream side of a cleaning blade 23 in the rotating direction of the photoreceptor 11. A control means transmits an on/off signal to a solenoid 25 every specified time based on the detection signal of a timer counting the actuating time of the device so as to reciprocate an actuation part 26 to bring the coating agent 4 into contact with a roller member 3. Simultaneously with such operation, the control means energizes a coating agent supply driving motor so as to rotate a brush 22 and the roller 3, whereby the coating agent 4 is supplied to the surface of the photoreceptor through the roller 3 and the brush 22. Meanwhile, the coating agent is removed by the brush 22, a developing brush and the cleaning blade 23 which come in contact with the photoreceptor 11 in the midst of operation for forming the image.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a printer and a facsimile machine which uses an electrophotographic system.

[0002]

2. Description of the Related Art An image forming apparatus such as a copying machine, a printer and a facsimile apparatus using an electrophotographic system rotates a photoconductor during image formation to uniformly charge the image with a charging device and then exposes the image with an exposing means. To form an electrostatic latent image, the electrostatic latent image is developed by a developing device to form a toner image, the toner image is transferred to a sheet such as transfer paper by a transfer unit, and then fixed by a fixing device. The residual toner on the photoconductor was cleaned by a cleaning device.

A discharge by a corona charger is used as the transfer means and the charging device. When a so-called corona charger method is used, ozone and nitrogen oxides are generated during discharge, and those generated react with each other to purify ammonium nitrate and adhere to the surface of the photoconductor. This ammonium nitrate is a water-soluble substance, and when attached to the surface of the photoconductor, it absorbs moisture in the atmosphere and reduces the resistance of the surface of the photoconductor. When the resistance of the surface of the photoconductor decreases, the photoconductor cannot maintain a predetermined potential, which causes so-called image deletion.

In the case of a photoconductor having a relatively soft surface such as an organic photoconductor, since the photoconductor surface is gradually abraded, the above-mentioned problems due to the accumulation of ammonium nitrate on the surface of the photoconductor are unlikely to occur. In the case of an inorganic photoconductor, an amorphous photoconductor, or a photoconductor whose surface is coated with a hard substance, the surface of the photoconductor is less likely to be scraped, so ammonium nitrate tends to accumulate on the photoconductor surface, which causes the above-mentioned problems. Occurs.

Therefore, a technique has been considered in which the surface of the photoconductor is covered with a thin film and the thin film and ammonium nitrate are scraped together to constantly refresh the surface of the photoconductor to prevent image deletion.

[0006]

However, since the substance forming the thin film in the above technique has high lubricity, the friction coefficient of the surface of the photoconductor is lowered, and the separability of the transfer paper from the photoconductor is lowered. There was a problem. That is, when a lubricant is applied to form a thin film on the surface of the photoconductor, the adsorption force acting between the photoconductor and the toner is reduced, and the amount of toner adhering to the non-image area is extremely reduced. The adhesion between the body and the transfer paper is increased, and the separability is reduced.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an image forming apparatus capable of preventing a deposit from accumulating on the surface of a photoconductor without deteriorating the separability of a transfer paper and obtaining a stable image for a long period of time. To do.

[0008]

According to the first aspect of the present invention,
An image forming apparatus comprising: a coating agent supplying means for supplying a coating material to the surface of a photoconductor; and a removing means for removing the coating material supplied by the coating material supplying means, wherein the coating agent is provided every predetermined time. The control means controls the operations of the coating material supply means and the removal means so as to supply and remove the coating material.

According to a second aspect of the present invention, an image forming apparatus is provided with a coating material supplying means for supplying a coating material to the surface of the photoreceptor and a removing means for removing the coating material supplied by the coating material supplying means. At the time of starting the image forming apparatus,
It is characterized by further comprising control means for controlling the operation of the removing means so as to remove the coating material on the photoreceptor.

According to a third aspect of the present invention, an image forming apparatus is provided with a coating material supplying means for supplying a coating material to the surface of the photoconductor and a removing means for removing the coating material supplied by the coating material supplying means. The coating agent is supplied to the photoreceptor at the end of image formation, and the coating agent on the photoreceptor is removed when the image forming apparatus is started up so as to remove the coating agent on the photoreceptor. It is characterized by having control means for controlling the operation.

The invention described in claim 4 is the first or second invention.
Alternatively, the image forming apparatus according to the third aspect includes a developing unit including a developing brush that develops an image on the photoconductor, and a cleaning unit that cleans the photoconductor, and the removing unit is the developing unit and / or the developing unit. It is characterized in that it is the cleaning means.

[0012]

According to the first aspect of the invention, the control means controls the operations of the coating material supplying means and the removing means at predetermined time intervals to supply and remove the coating material to and from the photosensitive member. No deposits will accumulate.

According to the second aspect of the present invention, since the control means controls the operation of the removing means to remove the coating material from the photoconductor when the image forming apparatus is started up, deposits are accumulated on the surface of the photoconductor. Will not do.

According to the third aspect of the invention, the control means supplies the coating material to the photoconductor at the end of image formation, and removes the coating material on the photoconductor at the start-up of the image forming apparatus. The surface of the photoconductor can be protected from substances generated while being left unattended, and the deposits will not be accumulated on the surface of the photoconductor.

According to a fourth aspect of the invention, the developing means and / or
Alternatively, the cleaning means removes the coating material on the photoconductor.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 11 represents a photoconductor of the image forming apparatus, and reference numeral 10 represents a coating material supplying means for supplying a coating material to the photoconductor 11.

Around the photoconductor 11, a charger 12 for uniformly charging the surface of the photoconductor 11, an exposure optical system 13 for forming an electrostatic latent image on the photoconductor 11, and an electric charge in a non-image area are erased. Eraser 14, a developing device 15 for converting an electrostatic latent image into a visible image, a transfer charger 16 for transferring the visible image formed by the developing device 15 onto a transfer sheet, and a transfer sheet for transferring the visible image. And a cleaning blade 23 that abuts on the photoconductor 11 for removing toner remaining on the photoconductor 11 after transfer.
A cleaning unit 19 having the above and a charge eliminating lamp 18 for erasing the electric charge remaining on the photoconductor 11 are arranged.

As shown in FIG. 2, the coating material supplying means 10 is disposed on the downstream side of the cleaning blade 23 in the rotation direction of the photoconductor 11, and the brush 22 disposed in contact with the photoconductor 11. , Roller 3 driven to rotate in the direction of the arrow while being in contact with brush 22, and roller 3
It mainly consists of a solenoid 25 for selectively bringing the coating material 4 into and out of contact with a position abutting on and away from the position.

The brush 22 is rotationally driven in the direction of the arrow by driving means (not shown). As the brush 22, a plurality of loop-shaped polyester fibers having a bristle length of 6 mm are planted in a brush shape to have a diameter of 13 m.
The aluminum cylinder 21 of m is wound around the outer circumference of the cylinder 21.

The roller 3 is a stainless steel roller having a diameter of 16 mm, and the surface thereof is roughened to a surface roughness of about 5 μm by, for example, a sandblast method or the like, and innumerable fine recesses are formed. .

The coating 4 having one end in contact with the roller 3 is
The other end is fixed to the tip of the support member 24. The base end of the support member 24 is pivotally attached to an immovable member such as a machine frame by a shaft 24a, and the solenoid 2 is provided at the center of the support member 24.
The tip of the operating portion 26 of No. 5 is connected. Solenoid 2
5 is fixed to a stationary member, and is electrically connected to a control means 31 (see FIG. 3) for controlling the operation thereof.

As shown in FIG. 3, the control means 31 is connected to a timer 30 for measuring the operating time of the image forming apparatus. Based on this detection signal, the control means 31 sends an ON / OFF signal to the solenoid 25 at predetermined time intervals to reciprocate the operating portion 26 to bring the coating material 4 into contact with the roller member 3. At the same time as this operation, the control means 31 energizes the coating material supply driving motor 33 to rotate the brush 22 and the roller 3, and supplies the coating material 4 to the surface of the photoconductor 11 via the roller 3 and the brush 22. .

A scraper 29 is arranged on the downstream side of the coating material 4 with respect to the rotation direction of the roller 3 and on the upstream side of the contact portion with the brush 22. The scraper 29 is made of polyurethane rubber having a thickness of 1.5 mm and a length of 20 mm. The bite amount between the brush 22 and the photoconductor 1 is set to 2.5 mm, and the bite amount between the brush 22 and the roller 3 is set to 1.5 mm.

The material and shape of the roller 3 are not limited to those described above. The roller 3 is, for example,
Various metals, rubbers, expandable resins, or those whose surface is coated with another material may be used. Further, regarding the brush 22, the material, form, fiber thickness, bristle length,
The number of twists and the amount of bite are not particularly limited. The coating agent 4 is supplied to the photoconductor 11 via the roller 3 and the brush 22, but if a proper amount of the coating agent 4 can be supplied to the photoconductor 11,
The coating material 4 may be supplied to the photoconductor 11 by only one of the roller 3 and the brush 22. The materials and characteristics of the roller 3 and the brush 22 are selected in relation to the hardness and surface roughness of the photoconductor 11 and the system characteristics of the image forming apparatus.

The operation based on the above configuration will be described. By turning on an operation switch (not shown) of the image forming apparatus, the photoconductor drive motor 34, the developing device drive motor 35,
The developing bias power source 36 and the charger power source 37 are energized.

The charging charger 12 uniformly charges the surface of the image carrier 11 which rotates in the direction of the arrow, and then the exposure optical system 13 forms an electrostatic latent image on the photoconductor 11 according to the original to be copied. It is formed.

The eraser 14 removes unnecessary electric charges in the non-image area on the photoconductor 11 corresponding to blank areas such as areas between recording sheets and both ends of the recording sheet.
By supplying the toner to the photoconductor 11 side by the developing brush 27 of No. 5, the electrostatic latent image on the photoconductor 11 is visualized to form a toner image.

The toner image on the photoconductor 11 is transferred by the transfer charger 16 onto the transfer sheet fed to the transfer section.
After that, the transfer paper electrostatically adsorbed to the photoconductor 11 is discharged by the separation charger 17, separated from the photoconductor 11 and sent to the fixing device (not shown) to fix the toner image on the transfer paper. After that, the paper is ejected onto a paper ejection tray through a predetermined conveyance path.

The toner remaining on the photoconductor 11 without being transferred to the transfer paper in the above-mentioned transfer process is removed by the cleaning blade 23 of the cleaning device 9, and then the photoconductor 11 is irradiated with light by the charge eliminating lamp 18. When it is received, it is electrostatically initialized and used for the subsequent use.

When the timer 30 measures that the operation time of the image forming apparatus has reached the predetermined time, this detection signal is sent to the control means 31. Based on this detection signal, the control means 31 sends an ON / OFF signal to the solenoid 25 to bring the coating material 4 into contact with the roller member 3 and, at the same time, energize the coating material supply drive motor 33 to connect the brush 22 and the brush 22. The roller 3 is rotated. The coating material 4 is transferred to the fine recesses formed on the surface of the roller 3, is uniformized by the scraper 29, and is uniformly supplied to the surface of the photoconductor 11 by the brush 22. In this example, the coating material 4 is supplied every predetermined time, but it may be supplied every fixed number of copies. For example, when zinc stearate is used as the coating agent 4, the coating agent 4 is used for every 100 sheets of the photosensitive member 11 for one rotation.
May be brought into contact with the brush 22. This way,
The coating material 4 can be supplied to the extent that the separability of the transfer paper is not affected, and the surface of the photoconductor 11 can be refreshed.

In this case, the coating agent 4 is removed by the brush 22, the developing brush 27, and the cleaning blade 23 which are in contact with the photoconductor 11 during the image forming operation.
The operation timing of the solenoid 25 varies greatly depending on the type of the coating material 4, the contact conditions of the brush 22 and the scraper 29, the concentrations of ozone and NOx that cause image flow, and the state of the air flow inside the apparatus. Optimization is needed.

Since the substance causing the image deletion is gradually generated while the photoconductor 11 is left unattended, the coating material 4 is supplied to the photoconductor 11 at the end of the image formation, and when the image forming apparatus is started up. It is desirable to remove the coating material 4 on the photoconductor 11. Although it is possible to remove the coating material 4 only with the developing brush 27, it is preferable to simultaneously operate the brush 22 in order to perform the removal in a short time. In this case, the control means 31 sends an OFF signal to the solenoid 25 to separate the coating material 4 from the roller 3.

The control means 31 controls the charging charger 1 which is a source of ozone and NOx when the coating material 4 is supplied and removed.
2. The charger power source 37 of the transfer charger 16 and the separation charger 17 is turned off, and the developing bias power source 36 is applied in order to minimize toner consumption. If the coating material 4 is supplied and removed by the timer 30, the occurrence of time loss can be prevented.

[0034]

According to the first aspect of the invention, the control means controls the operations of the coating material supplying means and the removing means at predetermined time intervals to supply and remove the coating material to the photoconductor, and the surface of the photoconductor It is possible to provide an image forming apparatus capable of obtaining a stable image for a long period of time because image adherence does not accumulate on the surface of the image forming apparatus.

According to the second aspect of the present invention, the control means controls the operation of the removing means to remove the coating material from the photoconductor when the image forming apparatus is started up, and deposits are accumulated on the surface of the photoconductor. Since there is no image deletion, it is possible to provide an image forming apparatus capable of obtaining stable images for a long period of time.

According to the third aspect of the invention, the control means supplies the coating material to the photoconductor at the end of the image formation, removes the coating material on the photoconductor at the start-up of the image forming apparatus, and the image forming apparatus is left unattended. Since the surface of the photoconductor can be protected from the substances generated during the period of time, and the adhered substances do not accumulate on the surface of the photoconductor, image deletion is eliminated, and an image forming apparatus capable of obtaining a stable image for a long period of time can be provided.

In the invention described in claim 4, the developing means and / or
Alternatively, since the cleaning means removes the coating material on the photoconductor, it is not necessary to provide another removing means, and the cost is reduced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view of essential parts of a coating material supply unit in the image forming apparatus shown in FIG.

FIG. 3 is a block diagram illustrating a control operation of the image forming apparatus.

[Explanation of symbols]

 10 Coating Material Supplying Means 11 Photosensitive Body 12 Charging Charger 13 Exposure Optical System 14 Eraser 15 Developing Device 16 Transfer Charger 17 Separation Charger 18 Electrification Lamp 22 Brush 27 Developing Brush 31 Control Means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshiaki Miyashita 1-3-6 Nakamagome, Ota-ku, Tokyo, Ricoh Co., Ltd. (72) Inventor Ryo Tagami 1-3-6 Nakamagome, Ota-ku, Tokyo・ In Ricoh Co., Ltd. (72) Inventor Asami Koda 1-3-6 Nakamagome, Ota-ku, Tokyo ・ In Ricoh Co., Ltd.

Claims (4)

[Claims] 1. An image forming apparatus, comprising: a coating agent supplying means for supplying a coating material to the surface of a photoconductor; and a removing means for removing the coating material supplied by the coating material supplying means, for a predetermined time. An image forming apparatus comprising: a control unit that controls the operations of the coating agent supply unit and the removal unit so that the coating agent is supplied and removed every time. 2. An image forming apparatus comprising: a coating material supplying means for supplying a coating material onto the surface of a photoconductor; and a removing means for removing the coating material supplied by the coating material supplying means. An image forming apparatus comprising a control means for controlling the operation of the removing means so as to remove the coating material on the photoconductor when the apparatus is started up. 3. An image forming apparatus comprising: a coating material supplying means for supplying a coating material onto the surface of a photoconductor; and a removing means for removing the coating material supplied by the coating material supplying means. A control means for controlling the operations of the coating material supplying means and the removing means so that the coating material is supplied to the photoconductor at the end and the coating material on the photoconductor is removed when the image forming apparatus is started up. An image forming apparatus comprising: 4. The image forming apparatus according to claim 1, further comprising: a developing unit including a developing brush for developing an image on the photoconductor, and a cleaning unit for cleaning the photoconductor. An image forming apparatus, wherein the removing unit is the developing unit and / or the cleaning unit.