JP3313219B2 - Photoconductor cleaning method and electrophotographic copying machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cleaning a photosensitive member of an electrophotographic copying machine and an electrophotographic copying machine.

[0002]

2. Description of the Related Art Conventionally, in this type of electrophotographic copying machine and a method of cleaning a photoreceptor, a method of cleaning a photoreceptor 1 is such that toner which electrostatically adheres to the photoreceptor 1 after a transfer process is first used. At the same time, the cleaning member 13 is loosened by mechanical rubbing by the first cleaning member 13 and also serves as a charge elimination function. The charge on the photosensitive member 1 is eliminated to reduce the cleaning load on the second cleaning member 14, and then the photosensitive member 1 is cleaned. One is disclosed in JP-A-56-24382 and is known. As shown in FIG. 8, the cleaning means 2 provided in the direction of rotation of the photoconductor 1 and downstream of the transfer means 3 is a first cleaning member 13 which comes into pressure contact with the photoconductor 1.
And a second cleaning member 14 disposed behind the first cleaning member.
Reference numeral 13 denotes a conductive elastic roller, to which a voltage having a polarity opposite to the polarity of the ground or the electrostatic latent image is applied, and an elastic cleaning blade is used as the second cleaning member 14.

When the photosensitive member 1 is subjected to light elimination by the light irradiating means 6, the wavelength of the erasing light is irradiated with light of substantially the same color as the color of the toner to be developed in the last order to eliminate the charge. A method of cleaning the photoconductor 1 for cleaning is disclosed in JP-A-1-307773 and is well known. As shown in FIG. 9, the transfer means 3 transfers the color toner image obtained on the photoreceptor 1 to paper, and the fixing means transfers the color toner image to paper by the transfer means 3 and then heat-fixes the color toner image. A cleaning unit 2 for removing the color toner remaining on the photoconductor 1 after the transfer; and a light irradiation unit 6 for removing the charge of the photoconductor 1 between the transfer unit 3 and the cleaning unit 2. is there. Note that FIG.
In 9, 4 denotes a transfer charger, 5 denotes a charging unit, 8 denotes a transfer belt, and 9 denotes a developing unit.

[0004]

In the conventional method for cleaning a photosensitive member, which is electrically charged before the photosensitive member is mechanically cleaned as described above, the photosensitive member charged by a transfer means is charged. There is a problem that the charge cannot be sufficiently removed from the potential and cleaning failure of the photoconductor is likely to occur.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the conventional photoreceptor cleaning method, and to sufficiently remove the charged potential of the photoreceptor charged by the transfer means, thereby causing poor cleaning. An object of the present invention is to provide a method of cleaning a photoconductor, and an electrophotographic copying machine in which light emitted from a light irradiating unit for removing a charged potential of a photoconductor does not deteriorate detection accuracy of a photodetector provided in the vicinity thereof.

[0006]

According to the present invention, in order to achieve the above object, according to the first aspect of the present invention, a transfer potential is applied by a photoreceptor and a transfer charging means having a voltage control means. Transfer means having a belt or roller-shaped transfer member, cleaning means for removing toner remaining on the photoreceptor after the transfer step, charging means for charging the photoreceptor to form an electrostatic latent image, In an electrophotographic copying machine provided with developing means for developing a latent image formed on a body with toner, a surface of the photosensitive body is located between the developing point and an exposure point where a latent image is formed on the photosensitive body. A surface potential detecting means for detecting a potential is provided, and the photosensitive member is charged by a transfer member by rotating the photosensitive member while the operation of the charging means is stopped, and the charged potential is detected and output by the surface potential detecting means. Voltage control Fill in stage, the voltage control means is characterized in that to clean the transfer member a voltage applied to correct within a preset range, after the transfer step, the photosensitive member by a cleaning means. Claim 2
The present invention provides a transfer means including a photoreceptor, a belt or a roller-shaped transfer member to which a transfer potential is applied by a transfer charging means having a voltage control means, and removing toner remaining on the photoreceptor after the transfer step An electrophotographic copying machine provided with a cleaning means for cleaning and a charging means for charging a photoreceptor to form an electrostatic latent image, the cleaning means having a rotating conductive fur brush, and applying a potential to the conductive fur brush. Is provided, and when the conductive fur brush abuts on the photoreceptor, the potential applying means corresponds to the transfer potential so that no discharge occurs between the conductive fur brush and the photoreceptor. The voltage is applied to the conductive fur brush by changing the voltage, and the photosensitive member is rubbed by the conductive fur brush, and the photosensitive member is cleaned by the cleaning means. It is an. According to a third aspect of the present invention, there is provided a transfer unit including a photoreceptor, a belt or roller-shaped transfer member to which a transfer potential is applied by a transfer charging unit having a voltage control unit, and the transfer unit remains on the photoreceptor after the transfer process. In an electrophotographic copying machine including a cleaning unit for removing toner, a charging unit for charging a photoconductor to form an electrostatic latent image, and a toner supply control unit, a cleaning unit is provided between the transfer unit and the cleaning unit. A light irradiating means is provided, and the reflected light of the toner visual image formed on the photoreceptor is detected and output, and the output is input to the toner supply control means to reduce the toner concentration and the replenishment amount of the developer to a predetermined amount. Providing a light detection means to be maintained in the vicinity of the light irradiation means, after attenuating the charging potential generated on the photoreceptor by the light irradiation means,
When cleaning the photoreceptor by the cleaning means, the peak wavelength of the emission energy emitted by the light irradiation means is different from the wavelength at which the detection sensitivity energy of the light detection means is maximum. is there.

[0007]

According to the present invention as described above, a first aspect of the present invention is to detect a surface potential of a photoconductor between a portion at an exposure point where a latent image is formed on the photoconductor and developing means. Means for charging the photosensitive member by a transfer member by rotating the photosensitive member while the operation of the charging means is stopped, detecting the charged potential by a surface potential detecting means and outputting the charged potential to the voltage controlling means. The voltage control means corrects and applies a voltage to the transfer member within a preset range, and after the transfer step, cleans the photosensitive member with the cleaning means. According to a second aspect of the present invention, the cleaning means has a rotating conductive fur brush, and a potential applying means for applying a potential to the conductive fur brush is provided, and the conductive fur brush contacts the photosensitive member. When contacting,
The potential applying means changes the voltage in accordance with the transfer potential and applies the voltage to the conductive fur brush so that no discharge occurs between the conductive fur brush and the photosensitive member. The toner is rubbed by the conductive fur brush without causing toner to adhere to the conductive fur brush, and the photosensitive member is cleaned by the cleaning means. According to a third aspect of the present invention, a light irradiating means is provided between the transfer means and the cleaning means, and the reflected light of the toner visible image formed on the photoreceptor is detected and output, and the output is provided by the toner supply control means. Is provided near the light irradiating means for maintaining the toner concentration and the replenishment amount of the developer at a predetermined level by inputting the toner to the developer. When cleaning the photoreceptor by means, the peak wavelength of the emission energy emitted by the light irradiating means is different from the wavelength at which the detection sensitivity energy of the light detection means is maximum,
Even if the light from the light irradiation means enters the light detection means, it does not affect the detection accuracy of the light detection means.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In an electrophotographic copying machine embodying the present invention, the same parts as those of the conventional one are denoted by the same reference numerals, and description thereof will be omitted, and different parts will be mainly described.

The first embodiment shown in FIG.
A light irradiating unit 6 (hereinafter, referred to as PCL) having a neutralizing lamp for removing the charged potential of the photoconductor 1 is provided between the cleaning unit 2 and the transfer unit 3. And a transfer charging unit 4 having a voltage control unit 18 having a calculation unit (not shown) for applying a transfer potential to the transfer unit. Reference numeral 9 denotes a developing unit, 30 denotes a charge removing lamp after cleaning, 31 denotes a cleaning blade, and 32 denotes a toner conveying coil.

In such a device, after the transfer step, the photosensitive member 1 is irradiated with light at a level that attenuates the charging potential of the photosensitive member 1 by the PCL 6, and then the photosensitive member 1 is cleaned by the cleaning means 2. . That is, after the transfer step, the photoconductor 1 has an increased charging potential as shown in FIG. 2, and when there is no PCL6, when the paper is fed vertically in B5, the transfer current applied to the transfer member 8 is -80 μA. If
A defective cleaning image is generated on the copied image. However, when light irradiation is performed by the PCL 6, even if the transfer current is −100 μA, the charging potential of the photoconductor 1 can be attenuated, and no cleaning failure occurs. However, even when the light irradiation is performed, the charging potential of the photoreceptor 1 that has been irradiated with the light of the PCL 6 is set to a state in which the absolute value is lower than 600 V as shown in FIG. Since no bad image occurs,
The light irradiation energy level having an energy level equivalent to the exposure intensity for image formation is sufficient, and does not affect light fatigue of the photoreceptor 1.

In the above embodiment, if no PCL is provided, the transfer voltage is applied to the transfer member by the voltage control means, and the transfer current flowing according to the transfer potential value at that time, that is, the transfer potential is proportional to the transfer potential. The transfer member is charged by limiting the transfer current, and the photosensitive member 1 is cleaned so as not to cause a cleaning failure in cleaning performed after the transfer step. That is, when the transfer member is brought into contact with the photosensitive member, the transfer current flowing through the transfer member is limited so as to be equal to or lower than the charge potential of the photosensitive member provided by the charging means during normal image formation. The maximum upper limit is set to -150 μA, which can be switched according to the size of the transfer paper. Since the current easily flows to the photoconductor side as the transfer paper becomes narrower, the transfer current upper limit is set in accordance with the size of the transfer paper. That is, the transfer paper is set to be smaller for narrow paper than for wide paper, and set to be -60 μA for B5 vertical paper size and -80 μA for A4 horizontal paper size. After the transfer step, the photosensitive member 1 is cleaned.

In the second embodiment shown in FIG. 3, a surface potential detecting means 16 having a potential sensor is combined with an exposure portion 15 for forming a latent image on the photosensitive member 1 and a developing means 9 for developing the latent image with toner. It is provided between them. Before starting the image forming operation, the operation of the charging means 5 for charging the photoconductor 1 to form a latent image is stopped and the photoconductor 1 is rotated, and two levels of the transfer current, namely, -20 μA, Then -100 μA
Is applied to the transfer member 8 to charge the photoreceptor 1, and the charged potential of the photoreceptor 1 is detected and output by the surface potential detecting means 16, and the output and the paper size signal are converted into voltage control means 18. Of the photosensitive member 1 due to transfer member difference, mechanical difference, photosensitive member difference, etc., and paper size.
As shown in FIG. 2, the transfer current was set to
After correcting so that 600 V in the vertical direction and 400 V in the A4 horizontal direction are applied, the image forming operation is executed, and after the transfer process, the photoconductor 1 is cleaned. As a result, the cleaning of the photoconductor 1 can be made more reliable.

In the second embodiment, when the cleaning means uses a conductive fur brush, a bias voltage is applied to the conductive fur brush so that a discharge phenomenon does not occur due to a potential difference between the conductive fur brush and the photosensitive member. It is applied by voltage applying means. The condition under which the discharge phenomenon does not occur due to the potential difference between the conductive fur brush and the photosensitive member is such that the absolute value is 400 V or less from FIGS. The cleaning is performed by applying the voltage.

The cleaning means 2 in the second embodiment is as shown in FIGS.
Before the conductive fur brush 10 comes into contact with the photoreceptor 1, the neutralizing brush 11 shown in FIG. 4 or the neutralizing wire shown in FIG.
12 are provided. These discharge means are electrically installed, thereby discharging the conductive fur brush 10, and the static elimination brush 11 or the static elimination wire 12 is always a conductive fur brush 10 from which the toner has been removed by flicker. The cleaning performance is maintained by being cleaned, and the photosensitive member 1 is rubbed and cleaned by the conductive fur brush 10.

In the third embodiment shown in FIG. 7, the transfer means 3 has a transfer member 8 in the form of a belt or a roller, and a voltage control means 18 having a calculation means (not shown) for applying a transfer potential to the transfer member 8. A transfer charging means 4;
And a cleaning means 2, a PCL 6 having a discharge lamp for removing the charged potential of the photoconductor 1 is provided.
Light detecting means 7 (hereinafter referred to as P sensor) having a light detecting sensor is provided near L6. This P sensor 7
Has an optical sensor (not shown) for detecting the developing ability of the visible toner image formed on the photoconductor 1 by detecting reflected light.
When cleaning the photoconductor 1 by attenuating the charged potential of the photoconductor 1 by irradiating the CL6, even if the light of the PCL 6 enters the P sensor 7, the detection accuracy of the P sensor 7 is not affected. It is assumed that the peak wavelength of light emission of the PCL 6 is different from the peak wavelength of light receiving sensitivity of the P sensor 7, and these wavelengths are such that the emission peak wavelength of the PCL 6 is 600 to 700 nm (red light), P The peak wavelength of the light receiving sensitivity of the sensor 7 is 900 to 950 nm (infrared light). Reference numeral 9 denotes a developing unit, 30 denotes a charge removing lamp after cleaning, 31 denotes a cleaning blade, and 32 denotes a toner conveying coil.

[0016]

The present invention is as described above. According to the first aspect of the present invention, there is provided a photoreceptor and a belt or roller-shaped transfer member to which a transfer potential is applied by a transfer charging means having a voltage control means. Transfer means provided, cleaning means for removing toner remaining on the photoreceptor after the transfer step, charging means for charging the photoreceptor to form an electrostatic latent image,
In an electrophotographic copying machine having developing means for developing a latent image formed on a photoreceptor with toner, a photosensitive member is disposed between an exposure point for forming a latent image on the photoreceptor and the developing means. A surface potential detecting means for detecting the surface potential is provided, the photosensitive member is rotated by the transfer member while the operation of the charging means is stopped, and the charged potential is detected and output by the surface potential detecting means. The voltage is then input to the voltage control means. The voltage control means corrects and applies a voltage to the transfer member within a preset range. After the transfer step, the photosensitive member is cleaned by the cleaning means. Further, since the photosensitive member can be prevented from being excessively charged, there is an effect that cleaning failure can be reliably prevented. Claim 2
The present invention provides a transfer means including a photoreceptor, a belt or a roller-shaped transfer member to which a transfer potential is applied by a transfer charging means having a voltage control means, and removing toner remaining on the photoreceptor after the transfer step In an electrophotographic copying machine having a cleaning means for cleaning and a charging means for charging a photoreceptor to form an electrostatic latent image, the cleaning means has a rotating conductive brush and applies a potential to the conductive brush. A potential applying means that changes the voltage in accordance with the transfer potential so that no discharge occurs between the conductive brush and the photosensitive body when the conductive brush contacts the photosensitive body. Then, the photosensitive brush is rubbed by the conductive brush, and the photosensitive member is cleaned by the cleaning means. Can be prevented discharge between the photosensitive member and the conductive brush, the toner is not reduced toner removal effect of the conductive brush without charge, there is an effect that generates no cleaning failure. According to a third aspect of the present invention, there is provided a transfer unit including a photoreceptor, a belt or roller-shaped transfer member to which a transfer potential is applied by a transfer charging unit having a voltage control unit, and the transfer unit remains on the photoreceptor after the transfer process. In an electrophotographic copying machine including a cleaning unit for removing toner, a charging unit for charging a photoconductor to form an electrostatic latent image, and a toner supply control unit, a cleaning unit is provided between the transfer unit and the cleaning unit. A light irradiating means is provided, and the reflected light of the toner visual image formed on the photoreceptor is detected and output, and the output is input to the toner supply control means to reduce the toner concentration and the replenishment amount of the developer to a predetermined amount. A light detecting means to be maintained is provided in the vicinity of the light irradiating means, and after the light irradiating means attenuates the charging potential generated on the photoconductor, the cleaning means cleans the photoreceptor. Since the peak wavelength of the light emission energy emitted by the light irradiating means is made different from the wavelength at which the detection sensitivity energy of the light detecting means is maximized, the light detecting means does not perform erroneous detection by the light emission of the light irradiating means. This has the effect that the detection accuracy is high.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view of a first embodiment of the present invention.

FIG. 2 is a characteristic diagram illustrating a relationship between a transfer current, a cleaning blank, and a photosensitive member charging potential according to the first embodiment.

FIG. 3 is a schematic longitudinal sectional view of the second embodiment of the above.

FIG. 4 is a schematic vertical sectional view showing a part of a cleaning means of the second embodiment.

FIG. 5 is a schematic longitudinal sectional view showing a part of another cleaning means of the second embodiment.

FIG. 6 is a characteristic diagram illustrating a relationship between a conductive fur brush current and a transfer current according to the first embodiment.

FIG. 7 is a schematic longitudinal sectional view of the third embodiment of the above.

FIG. 8 is a schematic longitudinal sectional view of a conventional electrophotographic copying machine.

FIG. 9 is a schematic longitudinal sectional view of another electrophotographic copying machine of the above.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photoconductor 2 cleaning means 3 transfer means 4 transfer charging means 5 charging means 6 light irradiation means 7 light receiving means 8 transfer member 10 conductive fur brush 11 static elimination brush 12 wire 16 surface potential detection means

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Sadao Takahashi 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (56) References JP-A-63-95487 (JP, A) JP-A Sho 64-7086 (JP, A) Fully open 60-605967 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 21/10-21/12 G03G 21/00 370-540 G03G 21/14 G03G 15/00 303 G03G 15/16-15/16 103

Claims (3)

(57) [Claims] A transfer unit including a belt or a roller-shaped transfer member to which a transfer potential is applied by a transfer charging unit having a voltage control unit; and a toner remaining on the photoconductor after the transfer step. Cleaning means for removing, charging means for charging the photoreceptor to form an electrostatic latent image,
In an electrophotographic copying machine having developing means for developing a latent image formed on a photoreceptor with toner, a photosensitive member is disposed between an exposure point for forming a latent image on the photoreceptor and the developing means. A surface potential detecting means for detecting the surface potential is provided, the photosensitive member is rotated by the transfer member while the operation of the charging means is stopped, and the charged potential is detected and output by the surface potential detecting means. The voltage is input to the voltage control means, and the voltage control means corrects and applies a voltage to the transfer member within a preset range, and after the transfer step, cleans the photosensitive member with a cleaning means. Cleaning method of the photoconductor. 2. A photoconductor, a transfer unit including a belt or roller-shaped transfer member to which a transfer potential is applied by a transfer charging unit having a voltage control unit, and a toner remaining on the photoconductor after the transfer process. In an electrophotographic copying machine provided with a cleaning means for removing and a charging means for charging a photoreceptor to form an electrostatic latent image, the cleaning means has a rotating conductive fur brush. A potential applying means for applying a potential is provided. When the conductive fur brush contacts the photosensitive member, the potential applying means corresponds to the transfer potential so that no discharge occurs between the conductive fur brush and the photosensitive member. And applying a voltage to the conductive fur brush to rub the photoreceptor with the conductive fur brush and cleaning the photoreceptor with cleaning means. A method for cleaning a photosensitive member. 3. A photoconductor, a transfer unit including a belt or roller-shaped transfer member to which a transfer potential is applied by a transfer charging unit having a voltage control unit, and a toner remaining on the photoconductor after the transfer process. Cleaning means for removing, charging means for charging the photoreceptor to form an electrostatic latent image,
In an electrophotographic copying machine provided with a toner supply means, a light irradiation means is provided between the transfer means and the cleaning means, and the reflected light of a toner image formed on a photoreceptor is detected and output. A light detection means for inputting the output to the toner supply control means and maintaining the toner concentration and the replenishment amount of the developer at a predetermined amount is provided near the light irradiation means, and the charging potential generated on the photoreceptor by the light irradiation means is provided. After attenuating, when cleaning the photosensitive member by the cleaning unit, the peak wavelength of the emission energy emitted by the light irradiation unit is different from the wavelength at which the detection sensitivity energy of the light detection unit is maximum. An electrophotographic copier characterized by the following.