JP3515832B2 - Image forming device - Google Patents

Description

Description: 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 apparatus using an electrophotographic system. 2. Description of the Related Art Image forming apparatuses such as copiers, printers and facsimile apparatuses using an electrophotographic system rotate a photosensitive member at the time of forming an image and uniformly charge the image by a charging device. To form an electrostatic latent image, developing the electrostatic latent image by a developing device to form a toner image, transferring the toner image to a sheet such as transfer paper by a transfer unit, and fixing the toner image by a fixing device. Thereafter, the residual toner on the photoreceptor is cleaned by a cleaning device. [0003] As the transfer means and the charging device, a discharge by a corona charger is used. When a so-called corona charger method is used, ozone and nitrogen oxides are generated at the time of discharge, and those generated react to purify ammonium nitrate and adhere to the surface of the photoreceptor. This ammonium nitrate is a water-soluble substance, and when it adheres to the surface of the photoreceptor, it absorbs moisture in the atmosphere and lowers the resistance of the surface of the photoreceptor. When the resistance of the surface of the photoreceptor decreases, the photoreceptor cannot maintain a predetermined potential, causing a problem of so-called image deletion. In the case of a photoreceptor having a relatively soft surface such as an organic photoreceptor, since the surface of the photoreceptor is gradually scraped off, the above-mentioned problems caused by accumulation of ammonium nitrate on the surface of the photoreceptor are unlikely to occur. In the case of an inorganic photoreceptor, an amorphous photoreceptor, or a photoreceptor whose surface is coated with a hard substance, the surface of the photoreceptor is hard to be scraped, so that ammonium nitrate easily accumulates on the surface of the photoreceptor, and as described above, Occurs. Therefore, a technique has been conceived in which the surface of the photoreceptor is coated with a thin film, the thin film and ammonium nitrate are scraped off together, and the surface of the photoreceptor is constantly refreshed to prevent image deletion. However, since the substance forming the thin film in the above-mentioned technology has high lubricity, the coefficient of friction of the surface of the photoreceptor is reduced, and the separation of transfer paper from the photoreceptor is reduced. There was a problem of lowering. That is, when a lubricant is applied to form a thin film on the surface of the photoreceptor, the attraction force acting between the photoreceptor 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 increases, and the separability decreases. SUMMARY OF THE INVENTION Accordingly, 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 photoreceptor without deteriorating the separability of a transfer paper and obtaining a stable image for a long period. Is to do. Means for Solving the Problems The invention according to claim 1 is:
A coating agent supply means for supplying a coating agent to the surface of the photosensitive member, an image forming apparatus having a removal means for removing the supplied coating by the coating supply means, the photosensitive member
Developing means including a developing brush for developing the upper image;
Cleaning means for cleaning an optical body, and image formation
At the end, the coating agent is supplied to the photoconductor, and the
Remove the coating on the photoreceptor when starting
As described above, the operation of the coating material supply means and the removal means
And a control means for controlling said coating supply means, and a brush disposed in contact with the photosensitive member, the fine recesses in the surface is formed, the coating is in contact with the fine concave surface A roller that is driven to rotate while being in contact with the brush, disposed downstream of the roller in the rotational direction from the contact position between the roller and the coating material, and upstream of the contact position between the brush and the roller. , the roller contact, consists of a scraper to smooth the coating agent, by the control means the coating on the position apart from the contact position with the rollers, a solenoid for selectively contacting released, upper
The removing means is the developing means . According to the first aspect of the present invention, the control means controls the operations of the coating material supply means and the removing means at predetermined time intervals to apply the coating material to the photoreceptor. Since the supply and the removal are performed, the deposits do not accumulate on the surface of the photoconductor. 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 photoreceptor when the image forming apparatus is started up, so that the deposits accumulate on the surface of the photoreceptor. No longer. According to the third aspect of the present invention, the control means supplies the coating material to the photoreceptor at the end of the image formation, and removes the coating material on the photoreceptor at the time of starting the image forming apparatus. The surface of the photoreceptor can be protected from substances generated during standing, so that deposits do not accumulate on the surface of the photoreceptor. According to the fourth aspect of the invention, the developing means and / or
Alternatively, a cleaning unit removes the coating material on the photoconductor. Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 11 denotes a photoconductor of the image forming apparatus, and reference numeral 10 denotes a coating material supply unit that supplies a coating material to the photoconductor 11. Around the photoreceptor 11, a charging charger 12 for uniformly charging the surface of the photoreceptor 11, an exposure optical system 13 for forming an electrostatic latent image on the photoreceptor 11, and an electric charge in a non-image area are erased. Eraser 14, developing device 15 for visualizing the electrostatic latent image, transfer charger 16 for transferring the visible image formed by developing device 15 to transfer paper, and transfer paper for transferring the visible image Charger 17 for separating toner from photoconductor 11, and cleaning blade 23 in contact with photoconductor 11 for removing toner remaining on photoconductor 11 after transfer.
And a charge removing lamp 18 for erasing charges remaining on the photoconductor 11. As shown in FIG. 2, the coating material supply means 10 is disposed on the downstream side of the cleaning blade 23 in the rotation direction of the photoconductor 11, and is provided with a brush 22 arranged in contact with the photoconductor 11. A roller 3 that is driven to rotate in the direction of the arrow while contacting the brush 22;
And a solenoid 25 for selectively bringing the coating material 4 into and out of contact with and away from the position. The brush 22 is driven to rotate in the direction of the arrow by a driving means (not shown). As the brush 22, a plurality of polyester fibers formed in a loop shape with a bristle length of 6 mm are planted and formed into a brush shape, and the diameter is 13 m.
m is wound around the outer periphery of an aluminum cylindrical body 21. The roller 3 is a stainless steel roller having a diameter of 16 mm. The surface of the roller 3 is roughened to a surface roughness of about 5 μm by, for example, a sandblast method or the like, and countless fine concave portions are formed. . The coating agent 4, one end of which is in contact with the roller 3,
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 a stationary member such as a machine frame by a shaft 24a.
The distal ends of the five operating portions 26 are connected. Solenoid 2
Numeral 5 is fixed to a stationary member, and is electrically connected to control means 31 (see FIG. 3) for controlling its operation. As shown in FIG. 3, a timer 30 for measuring the operation time of the image forming apparatus is connected to the control means 31. Based on this detection signal, the control means 31 sends an on / off signal to the solenoid 25 at predetermined time intervals to cause the operating part 26 to reciprocate and 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 drive 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 disposed 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 between the brush 22 and the photoconductor 1 is set to 2.5 mm, and the bite 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, foamable resins, or their surfaces coated with another material may be used. Also, regarding the brush 22, the material, form, fiber thickness, hair length,
The number of twists, the amount of bite, and the like are not particularly limited. The coating material 4 is supplied to the photoconductor 11 via the roller 3 and the brush 22. If an appropriate amount of the coating material 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. When an operation switch (not shown) of the image forming apparatus is turned on, the photosensitive member driving motor 34, the developing device driving motor 35,
The developing bias power supply 36 and the charger power supply 37 are energized. After the surface of the image carrier 11 rotating in the direction of the arrow is uniformly charged by the charging charger 12, an electrostatic latent image corresponding to the document to be copied on the photoconductor 11 by the exposure optical system 13 is formed. It is formed. After the eraser 14 removes unnecessary charges in the non-image area on the photoconductor 11 corresponding to blank areas such as areas between recording papers and both ends of the recording paper, the developing device 1
When the toner is supplied 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 photosensitive member 11 is transferred by the transfer charger 16 to the transfer paper fed to the transfer section.
Thereafter, the transfer paper electrostatically attracted to the photoconductor 11 is discharged by the separation charger 17 to be separated from the photoconductor 11 and sent to a fixing device (not shown) to fix the toner image on the transfer paper. Thereafter, the sheet is discharged onto a sheet discharge tray via a predetermined transport path. After the toner remaining on the photoconductor 11 without being transferred to the transfer paper in the above-described transfer process is removed by the cleaning blade 23 of the cleaning device 9, the photoconductor 11 is irradiated with light by the neutralization lamp 18. Upon receipt, they are electrostatically initialized and provided for subsequent use. When the timer 30 measures that the operation time of the image forming apparatus has reached a predetermined time, this detection signal is sent to the control means 31. The control means 31 sends an on / off signal to the solenoid 25 based on the detection signal to bring the coating material 4 into contact with the roller member 3 and, at the same time, to energize the coating material supply drive motor 33 to make the brush 22 The roller 3 is rotated. The coating material 4 is transferred to the fine concave portions formed on the surface of the roller 3, is made uniform by the scraper 29, and is uniformly supplied to the surface of the photoconductor 11 by the brush 22. In this example, the supply of the coating material 4 is performed every predetermined time, but may be performed every fixed number of copies. For example, when zinc stearate is used as the coating material 4, the coating material
May be brought into contact with the brush 22. This way,
The coating agent 4 can be supplied to such an 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 removal of the coating material 4 is performed by the brush 22, the developing brush 27, and the cleaning blade 23, which come into contact with the photoreceptor 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, the scraper 29, the concentration of ozone and NOx causing image flow, and the state of the air flow inside the device. Optimization is required. Since the substance causing the image flow is gradually generated while the photoconductor 11 is left, the coating material 4 is supplied to the photoconductor 11 when the image formation is completed, and when the image forming apparatus is started up. It is desirable to remove the coating material 4 on the photoconductor 11. The removal of the coating material 4 can be performed only by the developing brush 27, but the brush 22 is preferably operated at the same time in order to perform the process 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 supplying and removing the coating material 4.
2. The charger power supply 37 of the transfer charger 16 and the separation charger 17 is turned off, and the developing bias power supply 36 is applied in order to minimize toner consumption. If the supply and removal of the coating agent 4 are performed by the timer 30, the occurrence of a time loss can be prevented. According to the first aspect of the present invention, the control means controls the operation of the coating material supply means and the removing means at predetermined time intervals to supply and remove the coating material to and from the photoreceptor. Since no deposits accumulate on the surface of the body, the image is eliminated, and an image forming apparatus capable of obtaining a stable image for a long time can be provided. According to the first aspect of the present invention, when the image forming apparatus is started up, the control means controls the operation of the removing means to remove the coating material from the photoreceptor, and the adhered substance is deposited on the surface of the photoreceptor. Since the accumulation is stopped, the image flow is eliminated, and an image forming apparatus capable of obtaining a stable image for a long time can be provided. According to the first aspect of the present invention, the control means supplies the coating material to the photoconductor at the end of the image formation, and removes the coating material on the photoconductor at the time of starting the image forming apparatus. Provided is an image forming apparatus that can protect the surface of the photoreceptor from substances generated while being left unattended and prevent the accumulation of deposits on the surface of the photoreceptor, thereby eliminating image flow and obtaining a stable image over a long period of time. it can. Further, in the first aspect of the present invention, a developing hands stage
There therefore removes coating on the photosensitive member, the cost reduction is not necessary to provide a separate removing means.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a sectional view of a main part 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. DESCRIPTION OF SYMBOLS 10 Coating agent supply means 11 Photoreceptor 12 Charger 13 Exposure optical system 14 Eraser 15 Developing device 16 Transfer charger 17 Separate charger 18 Static elimination lamp 22 Brush 27 Developing brush 31 Control means

──────────────────────────────────────────────────続 き 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 Ricoh Co., Ltd. (72) Inventor Asami Koda 1-3-6 Nakamagome, Ota-ku, Tokyo, Ricoh Co., Ltd. (56) References JP-A-6-324603 (JP, A) JP-A-5-119601 (JP, A) JP-A-6-149129 (JP, A) JP-A-52-15332 (JP, A) JP-A-63-261380 (JP, A) (JP, U) Real opening 63-43168 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 21/00 G03G 21/10 G03G 21/14 G03G 15/08 G03G 21 / 00 370-540

Claims (1)

(57) [Claim 1] A coating material supply means for supplying a coating material to the surface of a photoreceptor, and a removing means for removing the coating material supplied by the coating material supply means. An image forming apparatus, comprising: developing means including a developing brush for developing an image on the photoconductor
Cleaning means for cleaning the photosensitive member
And supplying the coating agent to the photoreceptor at the end of image formation.
The coating agent on the photoconductor at the time of starting the image forming apparatus
So that the coating agent supply means and the removing means are removed.
Control means for controlling the operation of the step, wherein the coating material supply means comprises: a brush arranged in contact with the photoreceptor; a fine recess formed on the surface; A roller that is driven to rotate while being in contact with the brush, downstream of a contact position between the roller and the coating material in a rotational direction of the roller, and upstream of a contact position between the brush and the roller. Arranged in contact with the roller, a scraper for leveling the coating material, and a solenoid for selectively contacting and separating the coating material at a position separated from the roller and at a position separated from the roller, The image forming apparatus , wherein the removing unit is the developing unit .