JP3188291B2 - Electrophotographic image forming apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

[0003]

2. Description of the Related Art In an electrophotographic image forming apparatus such as a laser printer, an ozone is generated by discharging a corona charger.
Although emission is generated, thereby deteriorated photoreceptor, for lowering the surface resistance is deposited on the photosensitive member, there is a problem such as blurring occurs in the transferred image, close to the corona charger 2. Description of the Related Art A fan is provided to discharge ozone generated by discharge of a corona charger to the outside.

However, since the exhaust fan as described above is rotated at a constant speed that does not affect the image process, when the photosensitive member is stationary, the air flow is insufficient and the exhaust fan faces the corona charger of the photosensitive member. When an ozone product adheres to a portion, particularly when the inside of the apparatus is left at a high temperature, moisture adheres to the adhered matter as a nucleus, causing a partial decrease in surface resistance, and as a result, image blurring may occur. Therefore, as disclosed in, for example, JP-A-61-50165, a fan for exhausting air around the corona charger is controlled so as to increase the exhaust amount when the corona discharger does not contribute to image formation. What has been proposed.

[0005]

However, in such an electrophotographic image forming apparatus, the amount of ozone generated varies depending on the surrounding environmental conditions, the state of the charger, and the like. It is difficult to reliably prevent the ozone product from adhering to the photoreceptor simply by increasing the displacement.

[0006] The present invention has been made in view of the above problems, and an object thereof is to allow the attachment of the ozone product to sensitive light body can be reliably prevented.

[0007]

[0008]

[0009]

In order to achieve the above object, the present invention provides a charger for uniformly applying a charge on a photoreceptor, and a charger arranged downstream of the charger for the photoreceptor. ,
In an electrophotographic image forming apparatus including a charge removing lamp for removing charges on the photoreceptor and a fan for transporting ozone generated due to discharge of the charger, light emission of the charge removing lamp Means for detecting a current flowing to the ground through the lower conductive layer of the photoreceptor charged by the charger, and air flow setting means for setting the air flow of the fan according to the current value detected by the means. It is provided. Further, the air volume setting means may be automatically activated when the power is turned on.

[0010]

[0011]

SUMMARY OF] According to the present invention, means for detecting a current flowing to the ground through the lower conductive layer of the charge removing lamp photoreceptor granted charge by a charger by the emission of the current value detected by said means Since the air flow of the fan is set according to the above, it is possible to reliably prevent the ozone product from adhering to the photoconductor. Further , if the respective setting operations are performed so as to be automatically performed when the power is turned on, the above-described respective effects can be reliably obtained.

[0012]

EXAMPLES The following specifically described based on examples and the like of the invention with reference to the accompanying drawings. FIG. 1 shows a reference of an embodiment of the present invention.
1 is a configuration diagram of a main part of an image forming apparatus. In this image forming apparatus, when setting a current to flow through the charger 1, a voltage is applied to the discharge electrode 1a by the DC power supply 2 to cause a discharge, and the photosensitive layer of the photoconductor 3 moving in the direction of arrow A is moved. 3a
After the charge is uniformly applied to the photosensitive layer 3a, the charge on the photosensitive layer 3a is removed by the light emission of the charge removing lamp 4.

As a result, the charged charges stored on the photosensitive layer 3a are discharged to the ground via the conductive layer 3b and the charging current detector 5. At this time, the charging current detector 5 detects a current generated by the movement of the electric charge, and sends information indicating the current value to the charging current setting circuit 6.

The charging current setting circuit 6 compares the current value with a preset value and sets a current flowing from the DC power supply 2 to the charger 1 so that the respective values match. That is, when the respective values match, the operating condition of the DC power supply 2 is determined, and the application of the voltage to the discharge electrode 1a ends. After the end of this series of operations, the image forming process operation is performed without changing the operating conditions of the DC power supply 2 until the operation is performed again.

The above-described series of operations are performed, for example, in FIG.
As shown in (1), when the power to the image forming apparatus main body is turned on, it may be automatically performed according to an instruction from a control unit (not shown). That is, when the power of the image forming apparatus is turned on, the charging device 1, the drive motor of the photosensitive member 3, and the discharging lamp 4 are turned on in step 1, and then the charging current detecting unit 5 is turned on in steps 2 to 5. And the charging current setting circuit 6 performs the above-described series of charging current setting operations. When the operation is completed, the process proceeds to step 6, in which the charging device 1, the drive motor of the photoconductor 3, and the discharging lamp 4 are turned off. I do. In addition, it is of course possible to start the above-described series of operations by other means, for example, an image formation start signal.

FIG. 3 is a configuration diagram of a main part of another image forming apparatus which is a reference of the embodiment of the present invention, and the same parts as those in FIG. 1 are denoted by the same reference numerals. In this image forming apparatus, 1
Reference numeral 1 denotes a photosensitive layer 3 of the photoreceptor 3 by image forming process equipment such as a charger, an exposure device, a developing device, and a transfer device (not shown).
a charging organize corona charger for adjusting the residual toner and residual charge polarity on the photosensitive layer 3a after transferring onto the transfer material a toner image formed on a uniformly.

When setting the current to flow through the charging arrangement corona charger 11, the AC power supply 12 and the DC power supply 13 apply a voltage in which an AC component and a DC component are superimposed on the discharge electrode 11a to discharge. After the charge is uniformly applied to the photosensitive layer 3a of the photoconductor 3 moving in the direction of arrow A, the charge on the photosensitive layer 3a is discharged by the light emission of the discharge lamp 14. Thereby, the charged charges on the photosensitive layer 3a are discharged to the ground via the conductive layer 3b and the current detection unit 15. At this time, the current detector 15 detects a current generated by the movement of the electric charge, and sends information indicating the current value to the current setting circuit 16.

The current setting circuit 16 compares the current value with a preset value, and determines a current flowing from the AC power supply 12 and the DC power supply 13 to the charging arrangement corona charger 11 so that the respective values match. Set. That is, the control of either the AC power supply 12 or the DC power supply 13 or both is performed, and when the current value from the current detection unit 15 matches the set current value, the operating conditions of the AC power supply 12 and the DC power supply 13 are determined. Then, the application of the voltage to the discharge electrode 11a ends.
After the series of operations, the image forming process operation is performed without changing the operating conditions of the AC power supply 12 and the DC power supply 13 until the control operation is performed again.

It is preferable that the above-described series of operations be performed automatically by an instruction from a control unit (not shown) when the power supply to the image forming apparatus is turned on, as shown in FIG. That is, when the power of the image forming apparatus main body is turned on, first, in step 11, the corona charger 11 for charging arrangement is used.
After the drive motor for the photosensitive member 3 and the lamp 14 for static elimination are respectively turned on, the current detection unit 15 and the current setting circuit 16 are caused to perform the above-described series of current setting operations in steps 12 to 15, and when the operations are completed. And proceed to step 16,
Corona charger 11 for charging arrangement, drive motor for photoconductor 3,
The charge removing lamps 14 are turned off. In addition, it is of course possible to start the above-described series of operations by other means, for example, an image formation start signal.

FIG. 5 is a structural view of a main part of an image forming apparatus showing one embodiment of the present invention, and the same parts as those in FIG. 1 are denoted by the same reference numerals. The image forming apparatus includes a fan 21 for transporting ozone generated by the discharge of the discharge electrode 1a in the charger 1. When the air flow of the fan 21 is set, the discharge lamp 4 is used. Charger 1
The charging current detection unit 5 detects a current flowing to the ground via the conductive layer 3b of the photoconductor 3 to which the electric charge has been applied, and the air volume setting circuit 22 controls the fan power supply 23 according to the current value. The air flow of the fan 21 is set by changing the condition of the fan power supply (DC power supply) 23 for driving the fan 21. After the series of operations is completed, the image forming process operation is performed without changing the operating condition of the fan power supply 23 until the operation is performed again.

The above-described series of operations may be automatically performed when an electric power is supplied to the main body of the image forming apparatus in accordance with an instruction from a control unit (not shown), as shown in FIG. That is, when the power of the image forming apparatus is turned on, the charging device 1, the drive motor of the photoconductor 3, and the discharging lamp 4 are turned on in step 21, and then the charging current detecting unit 5 is turned on in steps 22 and 23. And the air volume setting circuit 22 performs the above-described series of air volume setting operations. When the operation is completed, the process proceeds to step 24, where the charger 1, the photoconductor 3
Are turned off, respectively.
Further, it is of course possible to start the above-described series of operations in accordance with other means, for example, an image formation start signal.

[0022]

[0023]

[0024]

As described above , according to the first and second aspects of the present invention, the current flowing to the ground via the lower conductive layer of the photoconductor charged by the charger by the light emission of the charge removing lamp is provided. By detecting and setting the air flow of the fan according to the current value, the air flow of the fan becomes an air flow suitable for the ozone generation amount that changes depending on the surrounding environmental conditions, the state of the charger, etc. Ozone products can be reliably prevented from adhering to the surface.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a main part of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a charging current setting operation by the image forming apparatus of FIG. 1;

FIG. 3 is a main part configuration diagram of another image forming apparatus which is a reference of the embodiment of the present invention.

FIG. 4 is a flowchart illustrating a current setting operation performed by the image forming apparatus of FIG. 3;

FIG. 5 is a main part configuration diagram of an image forming apparatus showing one embodiment of the present invention.

FIG. 6 is a flowchart showing an operation according to the present invention by the image forming apparatus of FIG. 5;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Charger 1a Discharge electrode 2,13 DC power supply 3 Photoconductor 3a Photosensitive layer 3b Conductive layer 4,14 Static elimination lamp 5 Charging current detector 6 Charging current setting circuit 11 Corona charger for charging arrangement 12 AC power supply 15 Current detector 16 Current setting circuit 21 Fan 22 Air volume setting circuit 23 Fan power supply

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tatsuo Hirono 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Inventor Kazunari Yamada 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (72) Inventor Mami Osaki 1-3-6 Nakamagome, Ota-ku, Tokyo Stock Company Ricoh (72) Tetsuro Miura 1-3-6 Nakamagome, Ota-ku, Tokyo Stock Company Inside Ricoh (72) Inventor Kazunori Sakauchi 1-3-6 Nakamagome, Ota-ku, Tokyo Stock Company Ricoh (72) Inventor Masato Yanagida 1-3-6 Nakamagome, Ota-ku, Tokyo Stock Company Ricoh (56) References JP-A-2-250068 (JP, A) JP-A-3-122677 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 21/14 G03G 15/02

Claims (2)

(57) [Claims] 1. A charger for uniformly applying a charge on a photoconductor, and a charge eliminator disposed downstream of the charger of the photoconductor for removing the charge on the photoconductor. An electrophotographic image forming apparatus including a lamp and a fan for transporting ozone generated by the discharge of the charger, wherein a photosensitive member provided with a charge by the charger by emitting light from the discharge lamp. An electrophotograph comprising: means for detecting a current flowing to the ground via the lower conductive layer of the body; and air volume setting means for setting an air volume of the fan according to a current value detected by the means. Type image forming apparatus. 2. An electrophotographic image forming apparatus according to claim 1, further comprising means for automatically operating said air volume setting means when power is turned on.