JPS59147376A - Electrophotographic process cartridge - Google Patents

Abstract

PURPOSE:To obtain the same excellent images even when any cartridge is used by providing an adjusting means for adjusting the electrostatically charged potential of an electrophotographic sensitive body. CONSTITUTION:When copying operation starts, a high-voltage power source 23 operates to start corona discharge from an electrode 17; some of the corona current flows to the shield member 18 of a charger 4, another part flows to a grid 19, and the remainder flows to the photosensitive body 3. The corona current flowing to the grid 19 is applied to a constant-voltage element 21 to hold the grid 19 at some potential. The grid 19 of the charger 4 has plural tungsten or stainless-steel wires extended at specific intervals and is not provided at some part on an upstream side in the rotational direction of the drum. Consequently, the charging efficiency of a primary charger is improved without degrading the effect for holding the potential by the grid constant.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a Giko-Atsushi gloss cartridge which has a built-in electrophotographic photoreceptor and is detachable and replaceable from the main body of an electrophotographic apparatus.

An example of an electrophotographic apparatus using the above cartridge will be explained with reference to FIG.

Figure 1 shows a cross-sectional view of the main body C of the IL photographic device.
+= A mounting table that reciprocates on the rail R in the direction of arrow a. 2 is a small-diameter imaging element array such as a Tobundle element transmitter (product name: SELFOC) JP Parlens, and a document mounting table 1.
The original image 0 placed above is illuminated by the illumination lamp L,
The reflected light 1 is directed to an opening 15 provided in the cartridge 14 on the electrophotographic photosensitive drum 6 which is rotated by the array 2 in the direction of the arrow. Slit exposure follows the filter 16. Further, numeral 4 marks the corona radiation area on the drum 6, and uniformly charges the photosensitive drum 6 coated with an organic semiconductor photosensitive layer or the like when the image is exposed. The drum 6, which is uniformly charged by the photosensitive band unit 4, is exposed to one image by the element array 2, and the electrostatic charge +i! j +β is formed.

This electrostatic a image is then visualized by a developing device 5. −
The sheet P on the force stacking table S is fed onto the drum 6 by a feed roller 6 and a registration roller 7 that rotates at five timings in synchronization with the image on the photosensitive drum 6. Then, the toner image on the photosensitive drum 6 is transferred onto the sheet P by the transfer charger 8. After that, the separating means 9
The sheet P separated from the drum 6 by the guide 9 is guided to the fixing device 10 and the toner image on the sheet P is fixed.
is discharged to the top. - 10,000, the toner remaining on the drum surface after transfer is cleaned by the cleaning device 16, and the above image forming process is repeated.

In the above, the electrophotographic process cartridge has a frame body 1
Drum 3 in 4a. Charger 4. A developing device 5° cleaning device 16 is built-in. And 'this cartridge 14
As shown in FIG. 2, the process cartridge 140 frame 14a is attached to and removed from the main body C of the electrophotographic apparatus, that is, it is detachable. The sliding portion 14b is engaged and guided. Further, 1) is a front door of the main body C, which can be opened and closed with respect to the main body C, and in FIG. 2, it is connected to the main body C with a hinge at the lower side.

The cartridge 14 installed in the main body C is replaced with a new cartridge 14 based on the lifespan of the photoreceptor.

In the above, in addition to the cartridge 14A and the light body, the photosensitive charger 4. Developing device5. Although the cleaning device 16 is built in, a transfer charger 8 may also be built in (or conversely, the photosensitive charger 4 and/or the developing device 5 and/or the transfer charger 8 and/or The cleaning device 16 may be attached to the main body side instead of being built into the cartridge 14. In any case, only the photoreceptor is built into the whale cartridge to facilitate its replacement.

Now, it is common for photoreceptors to have different charging abilities depending on their production lot, depending on the production environment.

The charging ability of the photoreceptor varies, and a predetermined latent image potential cannot be obtained under certain charging conditions, and the dark area potential may become too high or too low. However, in the case of the above-mentioned gross cartridges, it is burdensome for the user to adjust the adjustment means on the main body depending on the cartridge. Forgetting to adjust it is also inconvenient because it is awkward.

The present invention aims to solve the various disadvantages mentioned above.

The present invention will be described in detail below with reference to the drawings.

In the embodiment shown in Fig. 3.4.5, a photoreceptor 6 and a photosensitive charger 4 are built into the cartridge 14, and a high voltage is applied to the charger 4. , a shield member 18 surrounding a part of the electrode 170, and a grid 19 in FIG. 6.4.

The cartridge 14 has a built-in adjusting means 20 for adjusting the charging potential of the photoreceptor. In the illustrated example, the means 20 connects a constant voltage element (varistor, Zener diode, etc.) 21 and a variable resistor 22 in series, and the variable resistor 22 side is grounded. Further, the cartridge 14 is provided with a contact 24 connected to the electrode 17.
4 is inserted into a predetermined position in the main body C and loaded, the contact 24 is connected to the contact 2 provided on the main body C side. Since this contact 25 is connected to the high voltage power supply 23 provided on the main body C side, when the contacts 24 and 25 are connected, the electrode 1
7, it becomes possible to apply high voltage.

In FIG. 6, the shield member 18 is electrically grounded and the adjustment means 20 are connected to the grid 19, and in FIG. 4 the shield member 18. Adjustment means 20 on the grid 19
In FIG. 5, the adjusting means 20 is connected to the shield member 18.

The operation shown in FIG. 6 will be explained first.

(Car) 1) First, the screw 14 is set in the copying apparatus main body C, and when the copy switch is turned on to start copying, the high-voltage power supply 23 is activated and the electrode 17 of the charger 4 starts corona discharge. A portion of the corona current generated by the corona discharge is applied to the shield member 18 of the charger, and a portion is applied to the grid 19.
A part of it flows to the photoreceptor 3. The corona current flowing through the grid 19 is applied to the constant voltage element 21 to maintain the grid 19 at a certain potential.

It is known that the potential of the photosensitive member is partially dependent on the grid potential of the charger. For example, as shown in FIG. 9, if the horizontal axis is the grid voltage and the vertical axis is the surface potential of the photoreceptor, the grid rotation pressure and the surface potential are approximately proportional and do not depend much on the current value l flowing to the electrode 17. It is also known that the grid has a great effect of making the surface potential of the photosensitive member uniform, and that the change in the corona current value due to environmental changes can be made relatively small.

Note that the grid 19 of the charger 4 is arranged at regular intervals (for example, 2 m).
A plurality of (for example, five) tungsten or stainless steel wires are stretched at intervals of m), and no grid is stretched on a part of the upstream side in the rotational direction of the drum. By doing this, the effect of keeping the potential constant by the grid will not be reduced (and the charging efficiency of the -order charger will also be the same).
By adjusting the voltage generated by means 2o by adjusting the resistance value of
Even if the power supply 7 also supplies a constant circulating current, the surface potential of the photoreceptor after being charged by the charger 4 can be kept constant even if the photoreceptor charging ability varies depending on the cartridge. Therefore, the above adjustment can be carried out at a factory or the like when assembling the cartridge, without bothering the user.

In the above case, the high voltage power supply 26 uses a constant current transformer to stabilize the current flowing through the grid to keep the voltage generated in the grid almost constant, and therefore the surface potential of the photoreceptor remains almost constant. It will be preserved. When a constant current transformer is used in this way, the photoconductor surface electrical disconnection (rl) becomes more stable against changes in the environment such as humidity and temperature.However,
Even in the case of a constant voltage transformer, the grid is maintained at a substantially constant potential due to the constant voltage characteristics of the voltage generating member connected to the grid, so this does not contradict the gist of the present invention.

(The same applies to the following examples.

) The grid 19 of the charger 4 and the shield member 18 may be connected to each other as shown in FIG. 4 and kept at the same potential. In this way, the voltage applied to the shield part 18 increases the current flowing in the direction of the photoreceptor, increasing the charging efficiency of the charger 4, and making it possible to achieve a high surface potential with a small primary current. .

As shown in FIG. 5, a method may be used in which the bias voltage applied to the shield member 18 of the charger 4 is changed by the adjusting means 20 depending on the photoreceptor in the cartridge.

This method is effective as a simple method if the potential on the photoreceptor can be maintained relatively uniformly.

In particular, in the case of charging by corona discharge A and C, the effect of controlling the photoreceptor potential by changing the voltage applied to the shield member is large and effective.

In FIG. 6, the cartridge 14 incorporates a photosensitive drum, a grid 19, and grid voltage generating means (adjusting means) 20 in which a varistor 21 and a variable resistor 22 are connected in series.

Electrode 17 of charger 4. The shield member 18 is attached to the side of the main body C of the apparatus to be photographed, and when the cartridge 14 is pushed into the main body C of the apparatus, the grid 19 is placed at a position facing the electrode 17 through the opening of the shield member 18. Thus, the discharger 4 is completed. In this figure, the shield member 18 is electrically grounded, but it may be connected to the voltage generating means 20. In this case, a contact connected to the means 2o is provided on the cartridge 14 side, and a contact connected to the shield member is provided on the main body C side, and when the cartridge 14 is inserted into the main body C and set, both contacts are connected. , so that the hand Pi 20 and the shield member 18 are connected.

FIG. 7 shows that the cartridge 14 is connected to the photoreceptor 6 and the varistor 2.
1 and a voltage generating means (adjusting means) 20 having a variable resistor 22 connected in series.

Charger 4 (electrode 17. shield member 18. grid 19
) is attached to main body C. 26 is a contact connected to the means 20; 27 is a shield member 18 and a grid 19;
The contact 26 is a contact connected to the cartridge 14.
The contacts 27 are respectively provided on the main body C side, and when the cartridge 14 is inserted into the fixed position in the main body C and set, both the contacts 26 and 27 are connected, and the means 2o, the shield member 1B, and the grid 19 are connected. .

In FIG. 7, the grid 19 may be omitted (or the shield member 18 may be electrically grounded).

As described above, it is preferable that the adjusting means (voltage generating means) is a combination of a constant pressure element (varistor, Zener diode, etc.) and a variable resistor. In other words, it is desirable that the 1iIA1 node means have both the function of generating a constant voltage as described above and the function of adjusting this voltage. Further, it is known that the voltage generated by constant voltage elements such as Zener diodes and varistors varies by a maximum of ±5% depending on the manufacturing loft, and it is also necessary to correct this variation.

Therefore, by using a constant voltage element to generate a voltage that is approximately 90% of the voltage applied to the shield system or the grid, and by making the remaining 10% or so generated by a variable resistor and making it adjustable, the two voltage generating members can be adjusted. It can satisfy both the functions, constant voltage property, and ability to adjust the voltage. That is,
As shown in Figure 10, A is the variation of the photoconductor added to the grid voltage, B is the variation of the constant voltage element, and the range of B is the range of the variation of the photoconductor. Make sure it doesn't get too bulky.

Therefore, the adjustment range of S5T variable resistance is A,! : The sum of B becomes part C, and the resistance value of the variable resistor is selected so that a voltage in this range is not generated. For example, in a cartridge configured as shown in FIG. 4, when a current value of -500 μA is applied to the electrode 17, the voltage generating means 2o has a current value of about -49 μA.
0 μA flows. So I used a constant voltage element and the rating was -600v.
By using a variable resistor with a maximum resistance of 400Ω, variations in the IN light body and variations in the varistor can be corrected.

Furthermore, as shown in FIG. 8, the constant voltage element 2o is placed on the side of the main body C, and a variable resistor 22 whose resistance value is set in accordance with the characteristics of the photoreceptor O is installed in the IJ jig 14. It may also be provided. In the figure, 28 is connected to the variable resistor /lJ+'
, the contact point 30 is connected to the grid 19 and is connected to the cartridge 14, - 10,000, 29
．． 31 is a contact connected to the constant voltage element 21 and is provided on the main body C side. When the cartridge 14 is inserted into the main body C and set, the contacts 28 and 30 are connected to the contacts 29 and 31, respectively, and the grid 19 is connected to the constant voltage element 21.
゜i=J variable resistance resistance 22 is connected.

The method shown in FIG. 8 can also be applied to the methods shown in FIGS. 4 to 7.

By connecting the illustrated constant voltage element to the high voltage side and the variable resistor to the low voltage side, a small variable resistor with low insulation resistance can be used as the variable resistor. Of course, the variable resistor may be placed on the high voltage side and the constant voltage element may be placed on the low voltage side (ground side).

Furthermore, although a variable resistor was used in the above example, it is also possible to select a fixed resistor with a resistance value corresponding to the characteristics such as the lightning charging capacity of the photoreceptor for each cartridge and use it within one cartridge to apply force. good.

Alternatively, the resistor may be omitted and a constant voltage element having voltage characteristics corresponding to the characteristics of the photoreceptor may be selected for each cartridge and used in the cartridge.

In addition to the above configuration, a developing device, a cleaner, a pre-exposure means, etc. may be added to the IJ head shown in FIGS. 6 and 7.

As described above, according to the present invention, since the charging potential is made constant for each electrophotographic process cartridge in accordance with the characteristics of the photoreceptor, it is possible to obtain equally good images no matter which cartridge is used. It is something.

Incidentally, the present invention relates to a computer and a word processor.

It can also be applied to electrophotography in which images are recorded using laser beams or LEI) light modulated according to recorded signals from facsimile transmitters or the like.

[Brief explanation of the drawing]

1 and 2 are explanatory diagrams of an example of an electrophotographic apparatus to which the present invention can be applied, FIGS. 6 to 8 are detailed explanatory diagrams of the present invention, FIG. 9 is an explanatory diagram of the grid effect, and FIG. 10 is the adjusting yoke 17i
J17) It is an explanatory diagram. 6 is an electrophotographic photosensitive drum, 4 is a charger, 17 is an electrode,
1B is a shield member, 19 is a grid, 21 is a constant voltage element, and 22 is a variable resistor. 87 no? 88 faces, -1--Takuba 11-''

Claims (1)

[Claims] An electrophotographic process cartridge that includes at least an electrophotographic photoreceptor and is removable and replaceable in an electrophotographic apparatus main body, the electrophotographic process cartridge having an adjusting means for adjusting the charging potential of the electrophotographic photoreceptor.