CN100478799C - Charging device and electrophotographic apparatus including the same - Google Patents

Abstract

In an image forming apparatus of the present invention, a scorotron charging device has a meshed grid electrode which is meshed more coarsely in a high-speed apparatus than a meshed grid electrode in a low-speed apparatus according to a circumferential velocity of a photoreceptor. With this arrangement, it is possible to charge the photoreceptor at a predetermined potential in the high-speed apparatus, without increase of the amount of ozone generation and upsizing of the image forming apparatus.

Description

Charging system and have the electro-photography apparatus of this Charging system

Technical field

The present invention relates to a kind of lift-launch on electro-photography apparatus, make as the Charging system of the surface charging of the photoreceptor of electrostatic latent image image-carrier and have the electro-photography apparatus of this Charging system.

Background technology

In the last few years, in image processing system, print speed had further realized high speed.In image processing system, the electro-photography apparatus that utilizes the electrofax mode also needs to improve peripheral speed as the photoreceptor of electrostatic latent image image-carrier corresponding to flying print.

Corresponding method comprises the method that does not improve rotation number and enlarge the diameter of photoreceptor, and does not enlarge the photoreceptor diameter and improve the method for rotation number.But,, all select to improve rotation number basically for fear of the maximization of device.

In addition, especially in the fast high-speed equipment of the peripheral speed of photoreceptor, make that the surface-potential stabilization ground of photoreceptor is charged to be reached predetermined potential (setting charged current potential) technology is absolutely necessary.This is because when the surface potential of photoreceptor is unstable, because of the variation of surface potential can produce the phenomenon that is called " substrate photographic fog ", and can cause the decline of gradation of drop-out colour.And, when surface potential is too high,, can impel " photoreceptor deterioration " because of withstand voltage relation with respect to the photoreceptor belt electric potential.

The charged Charging system of photosensitive surface is categorized as: the contact electrification mode of using charged roller, charged brush etc.; So that be the charged mode of noncontact of representative with the corona charging device of corona discharge.

The contact electrification mode makes live parts such as roller, brush directly contact with photoreceptor and makes electron attachment.Therefore, can carry out chargedly efficiently, the voltage that is applied to live part is low to get final product.And the generation of ozone that can cause environmental pollution is also few, and is comparatively favourable in environmental protection.

But in the contact electrification mode, the roll-gap region about 3～5mm that only can contact with contact component at photoreceptor, common is wide applies voltage.Therefore, existence applies the less shortcoming in zone.Because this shortcoming can make the photoreceptor belt predetermined potential in low-speed device, but in high-speed equipment, be difficult to make photoreceptor to arrive predetermined potential.And, because live part directly contacts with photoreceptor, so be easy to adhere to the rubbish etc. of contact component, in high-speed equipment, the problem of the photosensitive body surface surface damage that attachment causes is very big.

On the other hand, the charged mode of noncontact is used corona discharge, and therefore comparing with the contact electrification mode to need high voltage, can produce ozone.But it has the advantage that can extensively guarantee to apply the zone, also can make photosensitive body surface wear predetermined potential in high-speed equipment.And,, therefore can not damage photosensitive surface owing to directly do not contact with photoreceptor.

At this, with reference to the structure of Figure 45 simple declaration corona charging device.As shown in figure 45, in the corona charging device, have and applied high-tension charging wire 141.This charging wire 141 is maintained in the charging case 142 and conductively-closed.Charging case 142 is opened the face relative with photoreceptor.And via this open face, charging wire 141 is relative with photoreceptor to be disposed.Charging wire 141 is the direction of principal axis configuration with the direction vertical with the sense of rotation of photoreceptor.

Under this structure, apply wide (photoreceptor sense of rotation wide) that charging case 142 is depended in the zone.The wide of charging case 142 can enlarge by the radical that increases the charging wire 141 that inside has.

And in the corona charging device, comprise the charged mode of no grid electrode (corotron) and the charged mode of grid electrode (scorotron) arranged, for example on the books in day disclosure special permission communique " spy open flat 10-142904 communique (open day: on May 29th, 1998) ".

The charged mode of no grid electrode with the charged mode of grid electrode arranged differently be to have or not grid electrode.Corona charging device shown in Figure 45 is that the charged mode of grid electrode is arranged, and between charging wire 141 and photoreceptor, configuration has applied the cancellous grid electrode 143 of bias voltage.

Charging wire 141 is being applied in the high-voltage power supply after vibration.Therefore, in not disposing the charged mode of no grid electrode of grid electrode 143, the distance of photoreceptor and charging wire 141 changes in applying step, on the direction vertical with the sense of rotation of photoreceptor, has the problem of charged potential fluctuation.

Relative with it, disposing the having in the charged mode of grid electrode of grid electrode 143, even charging wire 141 vibrations, under the bias voltage that is applied to photoreceptor and grid electrode 143, electric current from the charging wire 141 by grid electrode 143 is absorbed, charged current potential is limited, and the surface potential of photoreceptor is saturated, becomes even.

The above-mentioned saturation value that becomes the photoreceptor belt electric potential can be by being applied to the Control of Voltage of grid electrode 143.Be made as A by apply the discharge potential that high-voltage power supply produces to charging wire 141, when the bias voltage that is applied to grid electrode 143 was B, when A＞B, saturation value was B, and when A≤B, saturation value is less than B.

So, there is the charged mode of grid electrode to compare with the charged mode of no grid electrode, by grid electrode 143 is set, complicated and charged decrease in efficiency though structure becomes, but advantage with the charged current potential of may command, therefore and can make the photosensitive surface uniform charged, in using corona discharge charged, become main flow.

Above-mentioned grid electrode 143 for example uses the device that forms polygonal openings such as a plurality of slits, sexangle on SUS conductive sheets such as (stainless steel, thick 0.1mm) by methods such as etchings.

And in the order hole of grid electrode 143,, then use mostly about the wide 1.0mm～1.4mm of slit, slit separation 1.16mm～1.56mm in the prior art, if having slit as opening.And if having the type of hexagonal opening as opening, the circumscribed circle diameter that then uses opening mostly is as the spacing of 2.5mm～3.4mm, circle about as 2.75mm～3.65mm.

But in existing corona charging device, there is following problem to be solved.

Because of the peripheral speed that requires photoreceptor of flying print also high speed, only widely apply this countermeasure of zone with expansion and be difficult to make photoreceptor to reach predetermined potential by what enlarge charging case.

That is, in the corona charging device, apply the zone by enlarging wide (the photoreceptor sense of rotation wide) of charging case 142, can enlarging.But, around photoreceptor, not only dispose Charging system, and dispose the known various parts that use in card Ademilson (Carlson) technologies such as developing apparatus, cleaning device, transfer device.Therefore, what enlarge charging case 142 widely applies the zone with expansion and has the limit, when charging case 142 wide excessive, in order to ensure the configuration space of miscellaneous part, can cause the drum footpath of photoreceptor to enlarge, and image processing system is maximized.

And, disclose in day disclosure special permission communique " spy open 2000-137368 communique (open day: on May 16th, 2000) ": the periphery in photosensitive drums is set up in parallel a plurality of grid electrode electro-mechanical parts that have, make the aperture opening ratio of grid electrode of the electro-mechanical part that is positioned at the upstream of photosensitive drums sense of rotation one side the highest, make the aperture opening ratio of grid electrode of the electro-mechanical part that is positioned at downstream one side minimum.

But, open above-mentioned spy that disclosed periphery in photosensitive drums is set up in parallel in the structure of a plurality of corona charging devices in the 2000-137368 communique, also can't solve the problem of maximization.

In addition, apply method beyond the zone, can consider by making the voltage that is applied to charging wire 141 very high, thereby in high-speed equipment, make photoreceptor reach the method for predetermined potential as expansion.But in this countermeasure, the ozone generating amount must increase, and is unfavorable for environmental protection.

And, when the further high speed of peripheral speed of photoreceptor, make area that photoreceptor is stipulated, uniform and stable predetermined potential difficulty itself in grid electrode.

Figure 46 represents to have the grid electrode Charging system to carry on the image processing system as electro-photography apparatus, the peripheral speed of photoreceptor is improved than existing value interimly, flow into the result of the relation of the electric current (hereinafter referred to as the electric wire electric current) of charging wire and the surface potential of photoreceptor (hereinafter referred to as the drum surface potential) with investigation.At this, make the electric wire electric current on be limited to 900 μ A.This is because when surpassing 900 μ A, the ozone generating capacity obviously increases.

In Figure 46, transverse axis is the electric wire electric current, and the longitudinal axis is the voltage (hereinafter referred to as electric wire voltage) that applies on drum surface potential and the charging wire 141.Wherein, the voltage (grid current potential) that is applied to grid electrode 143 for as the target current potential of drum surface potential 650 (V).And, the device of grid electrode 143 uses that the thin plate to the thick 0.1mm that is made of SUS forms a plurality of electrode wires between slit wide a plurality of slits as 0.15mm～0.17mm (error of 0.16mm ± 0.01mm), the wide 1.2mm of slit (slit separation 1.35mm～1.37mm (error of 1.36mm ± 0.01mm)).And charging wire 141 uses the tungsten line of Φ 60 μ, arranges two configurations on the sense of rotation of photoreceptor.The electrode of two charging wires is shared.

As shown in figure 46, if peripheral speed is 240mm/sec, then rouse surface potential arrive as the grid current potential-650V and saturated.But when peripheral speed was 420mm/sec, the drum surface potential no longer rose before arriving the grid current potential.And when further being 600mm/sec at a high speed, the drum surface potential can further not reach the grid current potential.

That is, therefrom as can be known, the relation of electric wire electric current and drum surface potential is subjected to the very big influence of photoreceptor peripheral speed, and peripheral speed is fast more, the difficult more grid current potential that reaches of drum surface potential.And the drum surface potential is irrespectively similar to peripheral speed with respect to the curve of electric wire electric current, along with peripheral speed accelerates, moves to OV one lateral deviation.

Summary of the invention

The object of the present invention is to provide a kind ofly can not increase the ozone generating amount and can not cause image processing system to maximize, can make the photoreceptor belt predetermined potential or can make Charging system, the electro-photography apparatus of the uniform and stable band predetermined potential of photoreceptor in high-speed equipment in high-speed equipment.

The applicant to achieve these goals, the method that has in the charged Charging system of grid electrode the electrostatic latent image image-carrier that can make high speed rotating except the wide countermeasure that applies the zone with increase that enlarges charging case stablize the electricity of area predetermined potential to use has been carried out various researchs within the bounds of possibility.

Consequently, found that thereby following content has produced the present application: the order hole of grid electrode is thick when setting slowlyer than peripheral speed by the order hole of the grid electrode that the photoreceptor peripheral speed is fast, need not apply the high pressure of the degree that produces the ozone problem, just can make the surface potential of photoreceptor arrive the grid current potential.

First Charging system of the present invention is: a kind of Charging system, lift-launch is on electro-photography apparatus, make the predetermined current potential of surface band of the electrostatic latent image image-carrier that is driven and rotates, comprise: electric wire, on the position relative with above-mentioned electrostatic latent image image-carrier, with the direction vertical with the sense of rotation of this electrostatic latent image image-carrier is the direction of principal axis configuration, and is applied in high voltage; Guarded electrode shields this electric wire, opens and the relative face of above-mentioned electrostatic latent image image-carrier; Cancellous grid electrode is configured on the face of opening of this guarded electrode, and wherein, the order hole of above-mentioned grid electrode is set at: the slow more order of the peripheral speed of above-mentioned electrostatic latent image image-carrier hole is close more, and the fast more order of peripheral speed hole is thick more.

And first electro-photography apparatus of the present invention is: a kind of electro-photography apparatus has: the electrostatic latent image image-carrier forms electrostatic latent image and is driven and rotates on the surface; Charging system, make the predetermined current potential of this electrostatic latent image image carrier surface band, wherein, above-mentioned Charging system has the charged device of grid electrode to constitute by one, this has the charged device of grid electrode to comprise: electric wire, on the position relative, be the direction of principal axis configuration with the direction vertical, and be applied in high voltage with the sense of rotation of this electrostatic latent image image-carrier with above-mentioned electrostatic latent image image-carrier; Guarded electrode shields this electric wire, opens and the relative face of above-mentioned electrostatic latent image image-carrier; Cancellous grid electrode is configured on the face of opening of this guarded electrode, and the order hole of above-mentioned grid electrode is set at: the slow more order of the peripheral speed of above-mentioned electrostatic latent image image-carrier hole is close more, and the fast more order of peripheral speed hole is thick more.

So, in high-speed equipment, the order hole of grid electrode is set at thicker than the order hole of low-speed device.By the order hole chap of grid electrode, the electric current (electric current from charging wire to the electrostatic latent image image-carrier) that grid electrode is drawn tails off, and more electric current arrives the electrostatic latent image image-carrier.Therefore, owing to be high-speed equipment,, also can improve chargeding performance even the electrostatic latent image image-carrier is shorter by the time (applying the time of electric charge) that applies zone (guarded electrode wide).

Consequently, can not increase the ozone growing amount, image processing system is maximized, in high-speed equipment, can make electrostatic latent image image-carrier band predetermined potential.

The applicant has carried out various researchs for achieving the above object.Found that following content and produced the present application: make near the thick charged value of electrostatic latent image image carrier surface to required charged current potential (predetermined potential), uniform charged is to required charged current potential afterwards, this multistage charged by carrying out, doing one's utmost to suppress to make the uniform and stable area of high-speed equipment predetermined potential under the state that the ozone generating amount increases and image processing system maximizes.

Second Charging system of the present invention is: a kind of Charging system, lift-launch is on electro-photography apparatus, make the predetermined current potential of surface band of the electrostatic latent image image-carrier that is driven and rotates, comprise: thick electro-mechanical part, make the surface charging of above-mentioned electrostatic latent image image-carrier reach near the value of above-mentioned predetermined potential, adjust electro-mechanical part, the surperficial uniform charged that makes above-mentioned electrostatic latent image image-carrier charged in this thick electro-mechanical part is to above-mentioned predetermined potential, above-mentioned thick electro-mechanical part and above-mentioned adjustment electro-mechanical part have in the charged device of grid electrode at one and constitute, this has the charged utensil of grid electrode to have: electric wire, on the position relative with the electrostatic latent image image-carrier, with the direction vertical with the sense of rotation of this electrostatic latent image image-carrier is the direction of principal axis configuration, and is applied in high voltage; Guarded electrode shields this electric wire, opens and the relative face of above-mentioned electrostatic latent image image-carrier; By the grid electrode that grid mesh part constitutes, be configured on the face of opening of this guarded electrode, this grid electrode has the close close zone in thick thick zone, order hole and order hole, and thick area configurations is in the sense of rotation upstream of above-mentioned electrostatic latent image image-carrier one side.

To achieve these goals, second electro-photography apparatus of the present invention is: a kind of electro-photography apparatus has: the electrostatic latent image image-carrier forms electrostatic latent image and is driven and rotates on the surface; Charging system makes the predetermined current potential of this electrostatic latent image image carrier surface band, and wherein, above-mentioned Charging system has: thick electro-mechanical part makes the surface charging of above-mentioned electrostatic latent image image-carrier reach near the value of above-mentioned predetermined potential; Adjust electro-mechanical part, the surperficial uniform charged that makes above-mentioned electrostatic latent image image-carrier charged in this thick electro-mechanical part is to above-mentioned predetermined potential, above-mentioned thick electro-mechanical part and above-mentioned adjustment electro-mechanical part have in the charged device of grid electrode at one and constitute, this has the charged utensil of grid electrode to have: electric wire, on the position relative with the electrostatic latent image image-carrier, with the direction vertical with the sense of rotation of this electrostatic latent image image-carrier is the direction of principal axis configuration, and is applied in high voltage; Guarded electrode shields this electric wire, opens and the relative face of above-mentioned electrostatic latent image image-carrier; By the grid electrode that grid mesh part constitutes, be configured on the face of opening of this guarded electrode, this grid electrode has the close close zone in thick thick zone, order hole and order hole, and thick area configurations is in the sense of rotation upstream of above-mentioned electrostatic latent image image-carrier one side.

Wherein, predetermined potential is meant by the electro-photography apparatus that has carried Charging system charged current potential decision, the electrostatic latent image image-carrier, is also referred to as and sets charged current potential.

So, thick electro-mechanical part makes near the thick charged value to predetermined potential in the surface of electrostatic latent image image-carrier, adjusts electro-mechanical part afterwards and makes electrostatic latent image image carrier surface uniform charged to predetermined potential.The charged purpose of thick electro-mechanical part is to make near the value of surface near predetermined potential, therefore need not to pay attention to the homogenising and the stabilization of current potential, can realize purpose in short electrification time.

And, the charged surface potential homogenising that is used to make near predetermined potential of adjusting electro-mechanical part, and be stabilized in predetermined potential, and therefore compare with making surface potential device charged and even and stabilization from the beginning, can in short electrification time, realize purpose.

So, the surface potential that makes the electrostatic latent image image-carrier by separation near the slightly charged of predetermined potential and make near should near value the surface potential homogenising and be stabilized in the charged function of adjustment of predetermined potential, even the further high speed of the peripheral speed of electrostatic latent image image-carrier also can do one's utmost to suppress to make the charged uniformly and stably predetermined potential that reaches of photoreceptor under the state that the ozone growing amount increases and electro-photography apparatus maximizes.

Further, according to said structure, thick zone is the bigger zone, order hole of comparing grid mesh part with close zone, and close zone is the less zone, order hole of comparing mesh with thick zone.

Promptly, thick zone is compared with close zone, when making electrode wires between opening wide identical, aperture area is bigger, and the opening number that exists in the unit area is less, and close zone is compared with thick zone, when making electrode wires between opening wide identical, aperture area is less, and the opening number that exists in the unit area is more.

But, needn't make the wide identical of electrode wires between opening in thick zone and close zone, thick zone is the big and thicker state of order of size with respect to close regional opening, close zone is a state less with respect to the size of thick regional opening and that order is closeer.

By making grid electrode is the structure with this thick zone and close zone, can make towards being adjusted in each zone of the discharge current of electrostatic latent image image-carrier differently, and the charged control of electrostatic latent image image-carrier can be carried out according to each zone.

Particularly, in the thick zone that is configured in sense of rotation upstream one side, because the order hole of mesh is bigger, therefore adjust throughput towards the discharge current of electrostatic latent image image-carrier, make current potential effect even, that be stabilized in predetermined potential lower, but because the throughput of discharge current is more, therefore can apply sufficient electric current, can make the surface of electrostatic latent image image-carrier thick at short notice charged near predetermined potential to the surface of electrostatic latent image image-carrier.

On the other hand, in the close zone of downstream one side that is configured in thick zone, because the order hole of mesh is less, therefore the throughput of discharge current is less, though be unsuitable for making at short notice the electrostatic latent image image-carrier charged, but can suitably control the throughput of discharge current, make the surface potential homogenising of the electrostatic latent image image-carrier that is in thick electriferous state and be stabilized in predetermined potential.

That is, by make in the charged device of grid electrode grid electrode by thick thick zone, order hole, and close close zone, order hole constitute, can make thick area part bear the function of thick electro-mechanical part, close area part is born adjust the function of electro-mechanical part.And realize thick electro-mechanical part in the charged device of grid electrode and adjust electro-mechanical part owing to can have, therefore under the structure of having separated charged function, also can avoid the maximization of Charging system at one.

The 3rd Charging system of the present invention is: a kind of Charging system, lift-launch is on electro-photography apparatus, make the predetermined current potential of surface band of the electrostatic latent image image-carrier that is driven and rotates, comprise: a wire, on the position relative with above-mentioned electrostatic latent image image-carrier, with the direction vertical with the sense of rotation of this electrostatic latent image image-carrier is the direction of principal axis configuration, and is applied in high voltage; Guarded electrode shields this electric wire, opens and the relative face of above-mentioned electrostatic latent image image-carrier; Cancellous grid electrode, be configured on the face of opening of above-mentioned guarded electrode, above-mentioned grid electrode has thick zone and the close zone that the order hole of mesh differs from one another, above-mentioned thick zone and close zone dispose successively from one side direction downstream, sense of rotation upstream, one side of electrostatic latent image image-carrier, and the border in above-mentioned thick zone and close zone is positioned at: the pairing position of peak value of the distribution of the above-mentioned electrostatic latent image image carrier surface current potential intensity of ratio expression is near the position of sense of rotation upstream one side of electrostatic latent image image-carrier.

The 3rd electro-photography apparatus of the present invention is: a kind of electro-photography apparatus has: the electrostatic latent image image-carrier forms electrostatic latent image and is driven and rotates on the surface; Charging system, make the predetermined current potential of this electrostatic latent image image carrier surface band, wherein, above-mentioned Charging system has the charged device of grid electrode to constitute by one, this has the charged device of grid electrode to comprise: a wire, on the position relative, be the direction of principal axis configuration with the direction vertical, and be applied in high voltage with the sense of rotation of this electrostatic latent image image-carrier with above-mentioned electrostatic latent image image-carrier; Guarded electrode shields this electric wire, opens and the relative face of above-mentioned electrostatic latent image image-carrier; Cancellous grid electrode, be configured on the face of opening of this guarded electrode, above-mentioned grid electrode has thick zone and the close zone that the order hole of mesh differs from one another, above-mentioned thick zone and close zone dispose successively from one side direction downstream, sense of rotation upstream, one side of electrostatic latent image image-carrier, and the border in above-mentioned thick zone and close zone is positioned at: the pairing position of peak value of the distribution of the above-mentioned electrostatic latent image image carrier surface current potential intensity of ratio expression is near the position of sense of rotation upstream one side of electrostatic latent image image-carrier.

According to said structure, the same with second Charging system, electro-photography apparatus, can utilizing one, to have the charged device of grid electrode to carry out thick charged and adjust charged.

And under said structure,, therefore represent that the distribution of electrostatic latent image image carrier surface current potential intensity has a peak value owing to use a wire.And in said structure, the border in above-mentioned thick zone and close zone is configured in than on the position near sense of rotation upstream one side of electrostatic latent image image-carrier, the position of an above-mentioned peak value correspondence.

By making the electrostatic latent image image-carrier charged, there is electric current (drum electric current) to flow on the surface of electrostatic latent image image-carrier.The intensity distributions of the surface potential of this drum current's intensity distribution and electrostatic latent image image-carrier is corresponding.That is, in the big part of the surface potential of electrostatic latent image image-carrier, the value of drum electric current becomes big, and in the little part of the surface potential of electrostatic latent image image-carrier, the value of drum electric current diminishes.Particularly, the peak value of the intensity distributions of the surface potential of electrostatic latent image image-carrier becomes the maximal value (peak value of drum electric current) of the value of bulging electric current.

Therefore, Charging system of the present invention also can show as: the border in thick zone and close zone must be near sense of rotation upstream one side of electrostatic latent image image-carrier than the position configuration of the peak value correspondence that bulging current's intensity distributes.

And, the border in above-mentioned thick zone and close zone is positioned at the position than sense of rotation upstream one side of the close electrostatic latent image image-carrier in the pairing position of peak value of the intensity distributions of the surface potential of electrostatic latent image image-carrier (the drum current's intensity distributes), therefore can make the size of the size in close zone greater than thick zone.In this case, can make that to adjust charged zone bigger, therefore can realize stable charged.

So, the varying in size of size by making thick zone and close zone, and make each zone with above-mentioned arranged in order, can be in each zone carry out with suitable order suitable charged.Therefore, do not increase the generation of ozone, electro-photography apparatus is maximized, can in high-speed equipment, make the charged predetermined potential that reaches of electrostatic latent image image-carrier.

Four-tape electric installation of the present invention is: a kind of Charging system, lift-launch is on electro-photography apparatus, make the predetermined current potential of surface band of the electrostatic latent image image-carrier that is driven and rotates, comprise: a plurality of electric wires, on the position relative with above-mentioned electrostatic latent image image-carrier, with the direction vertical with the sense of rotation of this electrostatic latent image image-carrier is the direction of principal axis configuration, and is applied in high voltage; Guarded electrode shields this electric wire, opens and the relative face of above-mentioned electrostatic latent image image-carrier; Cancellous grid electrode, be configured on the face of opening of above-mentioned guarded electrode, above-mentioned grid electrode has thick zone and the close zone that the order hole of mesh differs from one another, above-mentioned thick zone and close zone dispose successively from one side direction downstream, sense of rotation upstream, one side of electrostatic latent image image-carrier, and the border in above-mentioned thick zone and close zone is positioned at the pairing position of valley of the distribution of the surface potential intensity of representing above-mentioned electrostatic latent image image-carrier.

Quadrielectron photographic means of the present invention is: a kind of electro-photography apparatus has: the electrostatic latent image image-carrier forms electrostatic latent image and is driven and rotates on the surface; Charging system, make the predetermined current potential of this electrostatic latent image image carrier surface band, wherein, above-mentioned Charging system has the charged device of grid electrode to constitute by one, this has the charged device of grid electrode to comprise: a plurality of electric wires, on the position relative, be the direction of principal axis configuration with the direction vertical, and be applied in high voltage with the sense of rotation of this electrostatic latent image image-carrier with above-mentioned electrostatic latent image image-carrier; Guarded electrode shields this electric wire, opens and the relative face of above-mentioned electrostatic latent image image-carrier; Cancellous grid electrode, be configured on the face of opening of this guarded electrode, above-mentioned grid electrode has thick zone and the close zone that the order hole of mesh differs from one another, above-mentioned thick zone and close zone dispose successively from one side direction downstream, sense of rotation upstream, one side of electrostatic latent image image-carrier, and the border in above-mentioned thick zone and close zone is positioned at the pairing position of valley of the distribution of the surface potential intensity of representing above-mentioned electrostatic latent image image-carrier.

According to said structure, the same with second Charging system, electro-photography apparatus, can utilizing one, to have the charged device of grid electrode to carry out thick charged and adjust charged.

And in said structure,, therefore represent that the distribution of the surface potential intensity of electrostatic latent image image-carrier has a plurality of peak values owing to use many wires.In other words, there is valley in the intensity distributions of the surface potential of electrostatic latent image image-carrier.

As mentioned above, by making the electrostatic latent image image-carrier charged, on the electrostatic latent image image carrier surface, there is electric current (drum electric current) to flow.The intensity distributions of the surface potential of this drum current's intensity distribution and electrostatic latent image image-carrier is corresponding.That is, in the big part of the surface potential of electrostatic latent image image-carrier, the value of drum electric current becomes big, and in the little part of the surface potential of electrostatic latent image image-carrier, the value of drum electric current diminishes.Particularly, the peak value of the intensity distributions of the surface potential of electrostatic latent image image-carrier becomes the maximal value (peak value of drum electric current) of the value of bulging electric current, and the valley of the intensity distributions of the surface potential of electrostatic latent image image-carrier becomes the minimum value (valley of drum electric current) of the value of bulging electric current.

And according to said structure, grid electrode has following structure: the border in thick zone and close zone is positioned at the pairing position of valley (with the position of the valley correspondence of rousing electric current) of the distribution of the surface potential intensity of representing above-mentioned electrostatic latent image image-carrier.Promptly have following structure: the border in thick zone and close zone be configured in the electrostatic latent image image-carrier surface potential intensity distributions peak value, and adjacent with it peak value between on the corresponding position of valley of the intensity distributions that exists.

As mentioned above, the peak value of drum electric current is the bigger part of electric current that flows at the electrostatic latent image image carrier surface, therefore electrostatic latent image image-carrier charged is had bigger effect.Therefore if the border in thick zone and close zone is set near the peak value of bulging electric current, boundary position deviation slightly then, bigger variation will take place in the electric current that the electrostatic latent image image carrier surface flows, and is difficult to carry out stable charged.

On the other hand, the valley of drum electric current is the less part of electric current that flows at the electrostatic latent image image carrier surface, and is therefore less to the charged effect of electrostatic latent image image-carrier.Therefore if the border in thick zone and close zone is set near the valley of bulging electric current, even boundary position deviation slightly then, the variable quantity of the electric current that the electrostatic latent image image carrier surface flows is less.Consequently, can carry out stable chargedly, and charged control is more or less freely.

Therefore, do not increase the generation of ozone, electro-photography apparatus is maximized, can in high-speed equipment, make the charged predetermined potential that reaches of electrostatic latent image image-carrier.

In the Charging system that the present invention relates to, the area in above-mentioned close zone is preferably greater than the area in thick zone.According to said structure, can enlarge and adjust charged zone, can carry out stable charged efficiently.

Other purposes of the present invention, feature, advantage can be able to clearly by following content.And benefit of the present invention with reference to also can be able in the following explanation of accompanying drawing clear and definite.

Description of drawings

Fig. 1 (a) Fig. 1 (b) all be used for illustrating as first embodiment of the invention, used the figure in the order hole that the charged grid electrode that Charging system had of grid electrode is arranged.

Fig. 2 (a) Fig. 2 (b) all be used for illustrating as first embodiment of the invention, used the figure in the order hole that charged other grid electrodes that Charging system had of grid electrode are arranged.

Fig. 3 is the figure of structure of the image processing system of expression each Charging system of having carried the present invention's first to fourth embodiment.

Fig. 4 is the figure that is used for the structure from fixation unit to the transfer path of arranging paper disc of key diagram 3.

Fig. 5 (a) Fig. 5 (b) all is that expression is as figure first embodiment of the invention, that used the structure that the charged Charging system of grid electrode is arranged.

Fig. 6 is illustrated in to have used to have in the charged Charging system of grid electrode, the figure of relation when making the peripheral speed of photoreceptor variable, electric wire electric current and drum surface potential and electric wire voltage.

Fig. 7 is illustrated in to have used to have in the charged Charging system of grid electrode, makes the figure of the relation of wide when variable, the electric wire electric current of the slit of grid electrode and drum surface potential and electric wire voltage.

Fig. 8 is illustrated in to have used to have in the charged Charging system of grid electrode, makes the slit of the peripheral speed of photoreceptor and grid electrode wide variable, and the figure of the result when making photoreceptor charged.

Fig. 9 (a) Fig. 9 (b) all be used for illustrating as second embodiment of the invention, used the figure in the order hole that the charged grid electrode that Charging system had of grid electrode is arranged.

Figure 10 (a) Figure 10 (b) all be used for illustrating as second embodiment of the invention, used the figure in the order hole that charged other grid electrodes that Charging system had of grid electrode are arranged.

Figure 11 (a) Figure 11 (b) all are expressions as second embodiment of the invention, used the above-mentioned figure that the structure of the charged Charging system of grid electrode is arranged.

Figure 12 is illustrated in to have used to have in the charged Charging system of grid electrode, makes the figure of the relation of length on wide when variable, the photoreceptor of the slit of grid electrode and drum electric current.

Figure 13 is the synoptic diagram that the distribution of bulging electric current shown in Figure 12 is projected to the part of the length correspondence on the photoreceptor.

Figure 14 is that expression is as figure second embodiment, that used the configuration relation that charged above-mentioned Charging system of grid electrode and photoreceptor are arranged.

Figure 15 has had in the charged Charging system of grid electrode having used, and makes the wide variable and result's when making photoreceptor charged of the slit of grid electrode figure.

Figure 16 represents other embodiments of the present invention, is that the thick electro-mechanical part of expression is by there being the charged device of grid electrode to constitute, adjust the structural drawing that electro-mechanical part is made of the charged device of contact electrification mode.

Figure 17 is further other embodiments of the present invention, be the charged thick electro-mechanical part of the no grid electrode of expression and have the charged adjustment electro-mechanical part of grid electrode one have grid electrode charged in the structural drawing of realization.

Figure 18 (a) Figure 18 (b) all is the 3rd embodiments of the present invention, is to be used for illustrating the figure that has used the order hole that the grid electrode that the charged Charging system of grid electrode has is arranged.

Figure 19 (a) Figure 19 (b) all be used for illustrating as the 3rd embodiment of the present invention, used the figure in the order hole that other grid electrodes that the charged Charging system of grid electrode has are arranged.

Figure 20 (a) Figure 20 (b) all are expressions as the 3rd embodiment of the present invention, used the above-mentioned figure that the structure of the charged Charging system of grid electrode is arranged.

Figure 21 is illustrated in to have used to have in the charged Charging system of grid electrode, makes the figure of the relation of length on wide when variable, the photoreceptor of the slit of grid electrode and drum electric current.

Figure 22 is the synoptic diagram that the distribution of bulging electric current shown in Figure 21 is projected to the part of the length correspondence on the photoreceptor.

Figure 23 is illustrated in to have used to have in the charged Charging system of grid electrode, makes the wide variable and result's when making photoreceptor charged of the slit of grid electrode figure.

Figure 24 (a) Figure 24 (b) all is the 4th embodiments of the present invention, is to be used for illustrating the figure that has used the order hole that the grid electrode that the charged Charging system of grid electrode has is arranged.

Figure 25 (a) Figure 25 (b) all be used for illustrating as the 4th embodiment of the present invention, used the figure in the order hole that other grid electrodes that the charged Charging system of grid electrode has are arranged.

Figure 26 (a) Figure 26 (b) all are expressions as the 4th embodiment of the present invention, used the above-mentioned figure that the structure of the charged Charging system of grid electrode is arranged.

Figure 27 is illustrated in to have used to have in the charged Charging system of grid electrode, makes the figure of the relation of length on wide when variable, the photoreceptor of the slit of grid electrode and drum electric current.

Figure 28 is the synoptic diagram that the distribution of bulging electric current shown in Figure 27 is projected to the part of the length correspondence on the photoreceptor.

Figure 29 is illustrated in to have used to have in the charged Charging system of grid electrode, makes the wide variable and result's when making photoreceptor charged of the slit of grid electrode figure.

Figure 30 represents the 5th embodiment of the present invention, be to be illustrated in to have used to have in the charged Charging system of grid electrode the figure of the investigation result of the relation of the charged current potential of the photoreceptor when photoreceptor peripheral speed that respectively applies voltage under certain slit is wide and grid voltage do not apply.

Figure 31 is the photoreceptor peripheral speed that respectively apply voltage of certain slit of expression under wide and the figure of the investigation result of the relation of the charged current potential of the photoreceptor of grid voltage when not applying.

Figure 32 is the photoreceptor peripheral speed that respectively apply voltage of certain slit of expression under wide and the figure of the investigation result of the relation of the charged current potential of the photoreceptor of grid voltage when not applying.

Figure 33 is the photoreceptor peripheral speed that respectively apply voltage of certain slit of expression under wide and the figure of the investigation result of the relation of the charged current potential of the photoreceptor of grid voltage when not applying.

Figure 34 be expression certain apply the curve map of relation of the charged current potential (grid voltage does not apply) of wide photoreceptor peripheral speed of each slit under the voltage and photoreceptor.

Figure 35 be expression certain apply the curve map of relation of the charged current potential (grid voltage does not apply) of wide photoreceptor peripheral speed of each slit under the voltage and photoreceptor.

Figure 36 be expression certain apply the curve map of relation of the charged current potential (grid voltage does not apply) of wide photoreceptor peripheral speed of each slit under the voltage and photoreceptor.

Figure 37 be expression certain apply the curve map of relation of the charged current potential (grid voltage does not apply) of wide photoreceptor peripheral speed of each slit under the voltage and photoreceptor.

Figure 38 be expression certain apply the curve map of relation of the charged current potential (grid voltage does not apply) of wide photoreceptor peripheral speed of each slit under the voltage and photoreceptor.

Figure 39 is that each slit of expression is wide and respectively apply the curve map of the relation of charged current potential (grid voltage does not apply) under the voltage, photoreceptor peripheral speed and photoreceptor.

Figure 40 is the curve map of relation of the charged current potential (grid voltage does not apply) of the wide and photoreceptor of the slit that respectively applies voltage under the peripheral speed of certain photoreceptor of expression.

Figure 41 is the curve map of relation of the charged current potential (grid voltage does not apply) of the wide and photoreceptor of the slit that respectively applies voltage under the peripheral speed of certain photoreceptor of expression.

Figure 42 is the curve map of relation of the charged current potential (grid voltage does not apply) of the wide and photoreceptor of the slit that respectively applies voltage under the peripheral speed of certain photoreceptor of expression.

Figure 43 is the curve map of relation of the charged current potential (grid voltage does not apply) of the wide and photoreceptor of the slit that respectively applies voltage under the peripheral speed of certain photoreceptor of expression.

Figure 44 be represent respectively to apply under the peripheral speed of voltage and each photoreceptor, slit is wide and the curve map of the relation of the charged current potential of photoreceptor (grid voltage does not apply).

Figure 45 (a) Figure 45 (b) all is that the existing figure that the structure of the charged Charging system of grid electrode is arranged has been used in expression.

Figure 46 is illustrated in to have used to have in the charged Charging system of grid electrode, the figure of relation when making the peripheral speed of photoreceptor variable, electric wire electric current and drum surface potential and electric wire voltage.

Embodiment

With reference to accompanying drawing the embodiment that the present invention relates to is carried out following explanation.And the invention is not restricted to this.

(first embodiment)

According to Fig. 1 to Fig. 8 an embodiment of the invention are carried out following explanation.

At first, one-piece construction as the image processing system (electro-photography apparatus) of the Charging system 4A of present embodiment has been carried in simple declaration according to Fig. 3.

This image processing system is used for the monochrome image to predetermined paper (recording paper) formation and view data correspondence.This image processing system has as shown in Figure 3: image forming part 7, its photoreceptor 3, Charging system 4A, cleaning unit 5 by exposing unit 1, developing apparatus 2, drum type, and fixation unit 6 etc. constitute; Paper feed part 8; And row's paper portion 9.

Charging system 4A is used to make the surperficial homogeneous band predetermined potential as the photoreceptor 3 of electrostatic latent image image-carrier.In this image processing system, photoreceptor 3 for example carries out high speed rotating with peripheral speed 600mm/sec.

Specifically discuss after a while, 4A improves to this Charging system, make its can not cause photoreceptor 3 surfaces that image processing system do not make high speed rotating with maximizing evenly, the charged predetermined potential that reaches stably.

Exposing unit 1 is used to make surface by the photoreceptor 3 of Charging system 4A uniform charged according to the view data exposure of input, and forms the electrostatic latent image corresponding with view data on this surface.

As exposing unit 1, used the structure of laser scan unit (LSU) 13 in this illustration with laser irradiating part 11 and catoptron portion 12.For example also can use structure that light-emitting device array shapes such as EL, LED are arranged, EL or LED write head in addition.

And, in this image processing system,, adopted the method (being specially reference beam method) of using a plurality of laser in order to reduce the high speed of the irradiation sequential of following the flying print processing.

Developing apparatus 2 is used for making the electrostatic latent image development that forms on the surface of photoreceptor 3 with black toner.Cleaning unit 5 is used to remove, reclaim the toner that remains in photoreceptor 3 surfaces after the image transfer printing.

Transfer means 10 is used for and will be transferred to the paper that self transmits at the electrostatic image (not photographic fixing toner) of photoreceptor 3 surface developments as described.Transfer means 10 applies the electric field of the opposite charge polarity that has with electrostatic image to paper.For example, when electrostatic image had the electric charge of (-) polarity, the polarity that applies of transfer means 10 was (+) polarity.

The transfer belt 103 of driven roller 101 and driven voller 102 and other rollers is twined in configuration in the transfer means 10.This transfer belt 103 has predetermined resistance value (1 * 10 ⁹～1 * 10 ¹³The scope of Ω cm).

And, dispose conductive rollers 105 at the contact site of photoreceptor 3 and transfer belt 103.This conductive rollers 105 applies transfer electric field with the electric conductivity different with driven roller 101 and driven voller 102.This conductive rollers 105 has elasticity.So, photoreceptor 3 contacts by the plane with pre-Fixed width that is called transfer nip with transfer belt 103, has improved the transfer efficiency to the paper that sends.

Further, the back side one side of the transfer belt 103 of downstream one side of the transfer area of transfer belt 103 disposes and removes electric roller 106.Remove electric field that the paper of 106 pairs of transmission of electric roller is applied in transfer area and remove electricly, and the transmission of next step is carried out smoothly.

In addition, transfer means 10 disposes the cleaning unit of the toner dirt of removing transfer belt 103 and carries out the electrical mechanisms of removing of removing electricity of transfer belt 103.And should remove electrical mechanisms, and above-mentionedly remove electric roller 106 via this image processing system ground connection.

Be transferred to electrostatic image (not photographic fixing toner) on the paper by being sent to fixation unit 6 by transfer means 10, not photographic fixing toner fusion, photographic fixing is to paper.

Fixation unit 6 has warm-up mill 61, backer roll 62.Peripheral part at warm-up mill 61 disposes paper separation claw, roll surface temperature detection part (thermistor), roller cleaning surfaces parts.Have in the interior perimembranous of warm-up mill 61 and to make the warm-up mill surface be the thermal source of predetermined temperature (photographic fixing design temperature: roughly 160～200 ℃).

On the other hand, dispose the pressure-producing part that connects backer roll 62 to above-mentioned warm-up mill 61 with pre-level pressure piezometric at the two ends of backer roll 62.Further, the same in the periphery of backer roll 62 with the periphery of warm-up mill 61, dispose the cleaning member on paper separation claw, roller surface.

The pressure contact portion of warm-up mill 61 and backer roll 62 is called fusing nip, and paper is sent to this fusing nip.The fusion of fixation unit 6 by warm-up mill 61 surface temperatures, and the effect of jettisoninging that causes of the crimp force paper that will transmit to paper on the toner photographic fixing of not photographic fixing on paper.

Paper feed part 8 accumulative images form employed paper, provide paper to above-mentioned image forming part 7.In this image processing system, its purpose is to carry out flying print and handles.Therefore below image forming part 7, dispose multistage paper feeder 81, it has the paper that can accommodate 500～1500 shaping sizes in each paper feed tray, and, dispose the high capacity paper feeding box 83 that can accommodate multiple paper in a large number in the side of multistage paper feeder 81.And, at the main employed manual feed dish 82 in the printing of indefinite form size etc. of the sidewall of image forming part 7 configuration.

Row's paper portion 9 is configured in this image processing system and manually coils on the side of 82 opposite sides.In Fig. 3, example the example that constitutes by one section row's paper disc 91 of row paper portion 9.Also can replace and arrange paper disc 91, optionally the after-treatment device of configuration row paper disc (bookbinding, perforation processing etc.), multistage row paper disc.

Then the paper transfer step is described.Select in a plurality of paper feed tray from paper feed part 8 and accommodated the paper feed tray of printing the consistent paper of requirement.Transmit paper from selected paper feed tray.The paper that transmits by a plurality of transfer roller 16......, is sent to and is configured in transfer means 10 registration roller 35 before in transfer path shown in Figure 3 15, temporarily stops at this.The paper that temporarily stops to rotate once more with the top of form sequential registration roller 35 consistent with the electrostatic image on the photoreceptor 3, thereby is sent to transfer means 10, and not photographic fixing toner image is transferred.Paper is sent to fixation unit 6 afterwards, and the photographic fixing toner is not fixed, and is discharged to row's paper disc 91 of paper portion 9 afterwards.

And, in this image processing system, the transfer path from fixation unit 6 to row's paper disc 91 because of patterns such as copy mode, printing model, FAX pattern, and single face print different with the printing model of duplex printing.

Usually under copy mode, because the user operates near device, so that paper is discharged up is more.Discharge up and be meant that printing surface (image forming surface) exports up.Therefore and in printing model and FAX pattern, because the user scarcely near device, discharges more down.Discharge down be meant the paper that can make discharge according to the number of pages discharging, printing surface (image forming surface) exports down.

In this image processing system, the transfer path as from fixation unit 6 to row's paper disc 91 as shown in Figure 4, disposes a plurality of transfer path I～VI, a plurality of pawl A～E of branch.Except the pawl E of branch of stationkeeping, the corresponding respectively not shown pawl position switching mechanism that constitutes by solenoid etc. that is provided with in the pawl A～D of branch.This mechanism is ON/OFF in the control device that is made of not shown CPU etc., thereby the transfer path of guiding paper is selected from a plurality of transfer path I～VI.

(1) single face is printed, discharge faces up

The paper that has passed through fixation unit 6 is before passing through transfer roller 30, and the open transfer path I that is connected with exit roller 32 of the pawl A of branch closes transfer path II.So, the fore-end of the paper of transmission is directed into the pawl A of branch and by transfer path I, is discharged on the paper disc 91 through exit roller 32.

(2) single face is printed, discharge faces down

The paper that has passed through fixation unit 6 is before passing through transfer roller 30, and the open transfer path II of the pawl A of branch closes transfer path I.Further, the open transfer path III of the pawl C of branch closes transfer path V.The leading section of the paper that transmits is branched pawl A guiding, thereby by transfer path II.And, move transmission pawl B by the waist and the conveying capacity of top of form, behind open transfer path III, be directed into transfer path III by the pawl C of branch.

When the paper rear end arrived the position of the pawl E of branch, paper transmitted and temporarily stops, and the open transfer path IV of the pawl C of branch closes transfer path V.At this moment,, carry out change in location naturally, close transfer path II by the elastomeric element (spring etc.) that is configured on branch's pawl retainer shaft though the pawl B of branch is not shown.Behind this state, the transmission again of paper is carried out in counter-rotating transfer roller 33 reverse rotations, begins by behind the transfer path IV from the rear end of the position that is trapped in the above-mentioned pawl E of branch, is discharged to paper disc 91 through exit roller 32.

(3) discharge under the double face printing method

First (front) printed and finished, and the paper that has passed through fixation unit 6 is before passing through transfer roller 31, and the pawl A of branch opens transfer path II, closes transfer path I.Further, the open transfer path V of the pawl C of branch closes transfer path III.And, the open transfer path IV of the pawl D of branch.The leading section of the paper that transmits is branched pawl A guiding, thereby by transfer path II.And, after waist by top of form and conveying capacity move and transmit pawl B, be branched pawl C guiding to transfer path V, and transfer path IV.When the paper rear end arrived transfer path IV, the transmission of paper temporarily stopped (first face goes back to end).

Afterwards, the pawl D of branch closes transfer path V, when the transfer path that arrives the pawl E of branch is open, goes back to roller 34 reverse rotations, thereby carries out the transmission again of paper.The paper that is trapped in the position of above-mentioned transfer path IV passes through transfer path III from the rear end by the pawl E of branch, is sent to and is configured in above-mentioned print processing step (transfer means) registration roller 35 before.Afterwards, finish second (reverse side) and print, the paper that has passed through fixation unit 6 carries out and the identical processing of discharge that faces up under the single face of above-mentioned (1) is printed, and is discharged on the paper disc 91.

Then the Charging system 4A as present embodiment is elaborated.The applicant has carried out various researchs to following content: have in the charged Charging system of grid electrode in use, apply the regional countermeasure with increase except enlarging the wide of charging case, can make the photoreceptor of high speed rotating stablize the charged predetermined potential that reaches.

Consequently found following content and finished the present invention: the order hole of the grid electrode when setting slowlyer than peripheral speed by the order hole of the grid electrode when fast with the photoreceptor peripheral speed is thick, need not apply the high pressure of the degree that produces the ozone problem, just can make the surface potential of photoreceptor arrive the grid current potential.

Fig. 5 (a) (b) represents the structure of above-mentioned Charging system 4A.And Fig. 5 (b) is that the A-A alignment among Fig. 5 (a) is looked sectional view.

Charging system 4A has: charging wire 41, charging case 42, grid electrode 43A.Charging wire 41 is to be applied in high-tension cable component by electrode 44.Charging wire 41 is kept by holding member 46/46 in charging box 42 inside.At this, 2 of charging wire 41 configurations.Apply identical voltage by electrode 44 to two charging wires 41/41.In addition, charging wire 41 also can be more than 1 or 3.And, when configuration is a plurality of, also apply the structure of different voltages to each charging wire 41/41.

Charging case 42 is that the direction of principal axis with charging wire 41 is the electric conductivity box parts of the face of length direction, the relative configuration with photoreceptor of opening.Apply the voltage different by electrode 45 to charging case 42 with charging wire 41.

Grid electrode 43A is configured on the face open in the above-mentioned charging case 42.Apply the bias voltage different to grid electrode 43A with charging wire 41.At this, also apply the voltage identical with charging case 42 by 45 couples of grid electrode 43A of electrode.In addition, also following structure: grid electrode 43A and charging case 42 insulation, and be applied in different voltage separately.

And grid electrode 43A is the grid mesh part with electric conductivity of a plurality of openings.Opening shape comprises the slit-shaped of the opening shown in the reference marker 50 among Fig. 1 (a), the polygon of the opening shown in the reference marker 51 among Fig. 2 (a).With the opening of calling slit-shaped in the following text is slit 50, claims that polygonal opening is polygonal opening 51 (opening 51).In addition, in Fig. 2 (a), as polygonal opening 51, example hexagonal opening.

And the order hole of grid electrode 43A is set according to the peripheral speed of photoreceptor, and the order hole when the order hole during peripheral speed fast (height) is set slowlyer than peripheral speed is thick.

Wherein, when the order hole of grid electrode 43A is when having the slit-type of slit, then can be by slit wide and slit separation stipulate, then stipulate if having the type of polygonal opening by external diameter of a circle and spacing.

Wide SW of slit and the slit separation SP among the grid electrode 43A shown in Fig. 1 (b) presentation graphs 1 (a) for example.

The wide SW of slit represents wide (size of the direction vertical with the length direction of slit) of a slit 50.Slit separation SP is illustrated in the interval of each center line (the upwardly extending center line in slit length side) of two adjacent on the direction vertical with the length direction of slit slits 50/50.

And, the external external diameter of a circle HW of polygonal opening among Fig. 2 (b) expression and the grid electrode 43A shown in Fig. 2 (a) 51, and the spacing HP of circumscribed circle.The spacing HP of circumscribed circle represents the interval of central point of each circumscribed circle of two adjacent polygonal openings 51/51.

The order hole slightly is meant to be compared when close with the order hole, between the slit 50/50 or during the electrode wires between the polygonal opening 51/51 wide identical, the area of slit 50 or polygonal opening 51 is bigger, and the number less state of slit 50 that exists on the unit area or polygonal opening 51.

And, close being meant when also the order hole is thick in order hole compared, between the slit 50/50 or during the electrode wires between the polygonal opening 51/51 wide identical, the area of slit 50 or polygonal opening 51 is less, and the more state of number of slit 50 that exists on the unit area or polygonal opening 51.

Particularly, this image processing system is corresponding to the peripheral speed 600mm/sec of photoreceptor 3, wide when being 0.15mm～0.17mm (error of 0.16mm ± 0.01mm) what form electrode wires between slit, the wide SW of slit of the grid electrode 43A among the above-mentioned Charging system 4A is set at 1.8mm～2.4mm, and (slit separation SP is 1.95mm～2.57mm).

And if use has the type of polygonal opening 51 as grid electrode, then corresponding to peripheral speed 600mm/sec, making external diameter of a circle HW is 3.5mm～4.5mm, makes the spacing HP of circumscribed circle be set at 3.75mm～4.75mm.

In addition, the object lesson in the order hole of the grid electrode 43A of example only is an example here, and material and variation in thickness by grid electrode 43A also can change under peripheral speed 600mm/sec equally.

That is, under the identical state of material and thickness, the order hole of grid electrode 43A changes to thick direction along with the peripheral speed of photoreceptor 3 accelerates, and suitably setting can be carried out normal charged order hole and gets final product.

As shown in Figure 5, this Charging system 4A is configured to: with respect to photoreceptor 3, be length direction with the direction vertical with the sense of rotation of photoreceptor 3, a side that is provided with electrode 44,45 be configured in the inboard of image processing system.

When making photoreceptor 3 charged, apply voltage about 4KV～6KV to each charging wire 41, and apply bias voltage with the charged current potential correspondence of photoreceptor 3 to grid electrode 43A.In addition, apply the differences such as polarity of the polarity of voltage because of the toner of visualization way, use.

And, the peripheral speed of the photoreceptor 3 of the corresponding high speed rotating in the order hole of grid electrode 43A, set than and the order hole of low-speed device correspondence thick, therefore can not produce the increase of ozone growing amount, image processing system is maximized, in high-speed equipment, can make the stably charged predetermined potential that reaches of photoreceptor 3.

Various results of study that then the applicant is implemented, discovery the present application describe.

1) under study for action, use the image processing system that carries the electro-photography apparatus of Charging system 4A as predetermined, change condition, investigation flow through the relation of the electric current (hereinafter referred to as the electric wire electric current) of charging wire 41 and the surface potential of photoreceptor (hereinafter referred to as the drum surface potential).And the upper limit of electric wire electric current is made as 900 (μ A).This is because when surpassing 900 (μ A), the ozone growing amount obviously increases.

Fig. 6 represents when the peripheral speed of change photoreceptor, the result of study how relation of electric wire electric current and drum surface potential changes.Transverse axis is represented the electric wire electric current, and the longitudinal axis represents to rouse the voltage (hereinafter referred to as electric wire voltage) that applies on surface potential and the charging wire.In the present embodiment, adopt the discharged-area development mode, and utilize the toner of negative charging, therefore need make the photosensitive surface negative charging to predetermined voltage, the polarity of electric current, voltage is for negative.Therefore unit markings is (V), (μ A).

Wherein, the voltage (grid current potential) that is applied to grid electrode 43A for as the target current potential of drum surface potential 650 (V).And, as grid electrode 43A, use is on the thin plate of the thick 0.1mm that is made of SUS, and forming with the electrode wires between slit wide is 0.15mm～0.17mm (error of 0.16mm ± 0.01mm), the wide 1.2mm of the slit (device of a plurality of slits of slit separation 1.35mm～1.37mm).And charging wire 41 uses the tungsten line of Φ 60 μ, arranges two configurations on the sense of rotation of photoreceptor.The electrode 44 of two charging wires 41/41 is shared.

As shown in Figure 6, if peripheral speed is 240mm/sec, then rouse surface potential arrive as the grid current potential-650V (650 (V)) and saturated.But when peripheral speed was 420mm/sec, the drum surface potential no longer rose before arriving the grid current potential.And when further being 600mm/sec at a high speed, the drum surface potential can further not reach the grid current potential.

That is, therefrom as can be known, the relation of electric wire electric current and drum surface potential is subjected to the very big influence of photoreceptor peripheral speed, and peripheral speed is fast more, the difficult more grid current potential that reaches of drum surface potential.And the drum surface potential is irrespectively similar to peripheral speed with respect to the curve of electric wire electric current, and along with peripheral speed accelerates, (V) lateral deviation is moved to O.

2) in addition, it is wide etc. that the applicant changes the slit of the thickness of distance, charging wire 41 of distance, grid electrode 43A and the photoreceptor of charging wire 41 and photoreceptor or grid electrode 43A, how the relation between electric wire electric current and the drum surface potential changed carried out above-mentioned the same investigation.

Result when Fig. 7 slit that represent one of them, that change grid electrode is wide.As grid electrode, use is on the thin plate of the thick 0.1mm that is made of SUS, and forming with the electrode wires between slit wide is 0.15mm～0.17mm (error of 0.16mm ± 0.01mm), the wide 1.2mm of slit (slit separation 1.35mm～1.37mm), the wide 0.6mm of slit (slit separation 0.75mm～0.77mm), the wide 2.4mm of the slit (device of slit separation 2.55mm～2.57mm).

The grid current potential here be too as the target current potential of drum surface potential 650 (V).Charging wire 41 uses the tungsten line of Φ 60 μ, arranges two configurations on the sense of rotation of photoreceptor.The electrode 44 of two charging wires 41/41 is shared.The peripheral speed 600mm/sec of photoreceptor.

As shown in Figure 7, during the wide 0.6mm of slit (w=0.6 among Fig. 7), even the electric wire electric current is that (electric wire voltage is-6500V (6500 (V))) to 900 (μ A), and the drum surface potential is that 500 (V), grid current potential no show 650 (V).When the wide 1.2mm of slit (w=1.2 in Fig. 7), to compare during with the wide 0.6mm of slit, the drum surface potential is near the grid current potential, but still can not arrive.On the other hand, when the wide 2.4mm of slit (w=2.4 among Fig. 7), the electric wire electric current is through 650 (μ A), and surface potential surpasses the grid current potential.

That is, therefrom as can be known, the relation of electric wire electric current and drum surface potential is subjected to the wide influence of slit of grid electrode 43A, during the electrode wires between slit wide identical, to a certain degree till, slit is wide big more, the drum surface potential can be the closer to the grid current potential.

This be because, have grid electrode charged in, drawn by grid electrode 43A to the electric current that photoreceptor flows from charging wire 41, but the order hole of grid electrode 43A becomes slightly, the electric current of grid 43A absorption tails off, and arrives photoreceptor morely.Because more electric current arrives photoreceptor, so the peripheral speed of photoreceptor accelerates, and the time (applying the time of electric charge) by applying zone (guarded electrode wide) also can be improved chargeding performance even shorter.

Wide when excessive when slit, opening by grid electrode 43A and the electric current that flow into photoreceptor increase too much but on the other hand.Consequently, the restriction to charged current potential that produces because of configuration grid electrode 43A does not play use fully, as a reference, though be unlikely to charged as no grid electrode, but the drum surface potential surpasses the grid current potential, is difficult to stably charged to predetermined potential (setting charged current potential).

At this, the grid electrode 43A that utilizes slit type is experimentized, and represented the relation that slit is wide, but if having the device of the type of polygonal openings 51 such as sexangle, when making electrode wires between opening wide identical with the external diameter of a circle of polygon too, the relation of electric wire electric current and drum surface potential is subjected to the influence in the order hole of grid electrode.

3) and, the applicant is conceived to above, attempt when suppressing the ozone growing amount, to make the surface potential of photoreceptor to arrive the grid current potential and can stably make charged for setting charged current potential, stipulate the order hole of grid electrode 43A thus, make the peripheral speed of photoreceptor variable in the scope of 350mm/sec～600mm/sec, carried out charging test.

Fig. 8 emphasis has been represented the result under 350mm/sec, 400mm/sec, 450mm/sec, 500mm/sec, the 600mm/sec.

Wherein, as grid electrode 43A, used the wide of electrode wires that on the thin plate of the thick 0.1mm that constitutes by SUS, makes between slit to keep certain, made wide 10 types of beginning from 1.0mm to increase of slit with 0.2mm unit at 0.15mm～0.17mm (error of 0.16 ± 0.01mm).And charging wire 41 uses the tungsten line of Φ 60 μ, arranges two configurations on the sense of rotation of photoreceptor.The electrode 44 of two charging wires 41/41 is shared.The upper limit of electric wire electric current is made as 900 μ A, the grid current potential be as the target current potential of drum surface potential 650 (V).The allowable upper limit value of ozone growing amount is that the ozone concentration that is discharged to outside the device via the ozone suction strainer that is configured on the device is below the 2.0mg/h.

The result is, under the no problem state of ozone growing amount, make bulging surface potential arrive the grid current potential, usefulness " zero " expression that can be normally charged, can't make bulging surface potential arrive usefulness " * * " expression of grid current potential though the ozone growing amount is no problem, though the drum surface potential can the arrive the grid current potential more usefulness " * 1 " of ozone growing amount expression is though the drum surface potential can arrive the charged control difficulty of grid current potential (surpassing the grid current potential) with " * 2 " expression.

As shown in Figure 8, there is the fast more wide big more tendency of slit of carrying out normal charged grid electrode 43A of the peripheral speed of photoreceptor, wide with the permission about 0.6～0.8mm between the upper and lower bound, along with peripheral speed accelerates and moves to the direction that enlarges.

For example, if the peripheral speed that adopts in the image processing system of present embodiment is 600mm/sec, then in the grid electrode 43A that thin plate constituted of the thick 0.1mm that constitutes by SUS, (slit separation 1.95～0.77mm/sec) can carry out charged normally by making the wide 1.8～2.6mm of being of slit.

And,, then in the grid electrode 43A that thin plate constituted of the thick 0.1mm that constitutes by SUS, can carry out charged normally by making the wide 1.4～2.0mm of being of slit if peripheral speed is 400mm/sec.If peripheral speed is 450mm/sec, then in the grid electrode 43A that thin plate constituted of the thick 0.1mm that constitutes by SUS, can carry out charged normally by making the wide 1.6～2.2mm of being of slit.If peripheral speed is 500mm/sec, then in the grid electrode 43A that thin plate constituted of the thick 0.1mm that constitutes by SUS, can carry out charged normally by making the wide 1.6～2.5mm of being of slit.

And, wide for 2.0mm by making slit in the grid electrode 43A that thin plate constituted of the thick 0.1mm that constitutes by SUS, be under 350～600mm/sec in the peripheral speed of photoreceptor 3, can carry out charged normally.Equally, though not concrete record, but in the grid electrode 43A that thin plate constituted of the thick 0.1mm that constitutes by SUS, by making polygonal external diameter of a circle is 4.0mm (spacing of circle)～4.25mm, peripheral speed at photoreceptor 3 is under 350～600mm/sec, can carry out charged normally.

As mentioned above, in this image processing system, by the order hole of the grid electrode 43A among the Charging system 4A that has the charged device of grid electrode to constitute, according to the peripheral speed of the photoreceptor 3 that carries on the image processing system, it is close more more slowly to be set at peripheral speed, and peripheral speed is fast more thick more.

So,, can not increase the growing amount of ozone and image processing system is maximized, in high-speed equipment, can make the electrostatic latent image image-carrier charged to predetermined potential even in the high-speed equipment of the peripheral speed 600mm/sec of photoreceptor 3.

And, particularly, if grid electrode is the structure with a plurality of slits, then can make the wide 1.8mm～2.4mm of being of slit in this grid electrode, slit separation is 1.95～2.57mm, if and grid electrode is the structure with a plurality of polygonal openings, then by make with this grid electrode in the external diameter of a circle of polygon be that the spacing of 3.5mm～4.5mm, circle is 3.75mm～4.75mm, even more than with 500mm/sec～600mm/sec, be driven the structure of rotating, also can make the electrostatic latent image image-carrier normally charged at the electrostatic latent image image-carrier.

(second embodiment)

With reference to Fig. 3, Fig. 9 to Figure 17 embodiments of the present invention are carried out following explanation.In addition for convenience of explanation, be marked with identical mark and omit its explanation having with the parts of the parts identical function that uses in the first embodiment.

Fig. 3 represents to carry the one-piece construction as the image processing system of the Charging system 4B of present embodiment.This image processing system substitutes Charging system 4A with Charging system 4B, is the main difference point with the image display device of first embodiment.4B also improves to Charging system, makes it can not cause image processing system to maximize and can make the photoreceptor 3 surperficial uniform chargeds of high speed rotating.

The applicant has carried out various researchs in order to realize following purpose: doing one's utmost to suppress can to make the uniform and stable area of photoreceptor predetermined potential under the state that the ozone generating amount increases and image processing system maximizes in high-speed equipment.

Found that make near the thick charged value to the required charged current potential of setting (predetermined potential) in surface of photoreceptor, uniform charged by having separated the charged of function, can be realized this purpose, thereby produce the present invention to setting charged current potential afterwards.

Figure 11 (a) (b) represents structure as the Charging system 4B of present embodiment.Charging system 4B has: charging wire 41, charging case 42, grid electrode 43B.

Grid electrode 43B is the same with grid electrode 43A, is configured on the face of the opening in the above-mentioned charging case 42, and is applied in the bias voltage different with charging wire 41.Also apply the voltage identical at this with charging case 42 by 45 couples of grid electrode 43B of electrode.Also grid electrode 43B and charging case 42 insulation in addition, and be applied in different voltage separately.

Grid electrode 43B is the grid mesh part with electric conductivity of a plurality of openings, and 43A is the same with grid electrode, has the slit 50 shown in Fig. 9 (a) figure (b), the polygonal opening 51 shown in Figure 10 (a) Figure 10 (b) etc.The difference of grid electrode 43B and grid electrode 43A is that gate electrode 43B has thick regional 52 and close regional 53 these two zones that the order hole differs from one another.

In grid electrode 43B, its order hole is the same with gate electrode 43A, and when being slit-type, wide and slit separation is stipulated by slit, if having the type of polygonal opening, then stipulates by external diameter of a circle and spacing.

And in grid electrode 43B, in the thick zone 52 and close regional 53, electrode between 50,50 of slits or polygonal opening 51,51 wide not necessarily identical, thick zone 52 is meant that close regional 53 are meant the state less with respect to thick regional 52 opening sizes, that order is closeer with respect to the state that close regional 53 opening sizes are big, order is thicker.

And, in this thick regional 52 and close regional 53,, also can make to being adjusted in each zone of the discharge current of photoreceptor 3 discharges differently even identical by the magnitude of current of charging wire 41 discharge, can carry out the charged control of photoreceptor 3 according to each zone.

At this, with reference to Figure 12, Figure 13 for the order hole in the grid electrode not simultaneously the electriferous state of photoreceptor how difference describes.

Figure 12 represents to make repeatedly in all cases, do not flow into photosensitive surface when charging wire applies voltage the simultaneously bulging current's intensity in order hole of grid electrode to distribute.In experiment, use the wide 0.6mm of slit, three kinds of grid electrodes of 1.2mm, 2.4mm (single pattern).

In Figure 12, when the length that forms the photoreceptor of transverse axis represents that the point on the pairing photoreceptor 3 of central part (central portion between the charging wire 41,41) with Charging system is 0.0mm, to sense of rotation downstream one side of photoreceptor 3, the distance of upstream one side, one side is-30.0mm～30.0mm to the upstream from sense of rotation downstream one side of photoreceptor 3.

And the longitudinal axis of Figure 12 is the drum electric current.The drum electric current is meant that the corona discharge of charging wire 41 causes that photosensitive surface is charged, and flow into the electric current of photosensitive surface.The value of drum electric current is the value with the distribution correspondence of photosensitive surface current potential, the distribution of drum electric current and the distribution correspondence of photosensitive surface current potential.That is, in the big part of photosensitive surface current potential, the value of drum electric current becomes big, and in the little part of photosensitive surface current potential, the value of drum electric current diminishes.

And Figure 13 represents to make this drum current's intensity distribution to project to the synoptic diagram of the part corresponding with the length of photoreceptor 3.In Figure 13, illustrated bulging current's intensity to distribute 54.Reference marker 43Z is the grid electrode of the employed single pattern of experiment in the drawings.

As shown in figure 13, drum electric current, (part on the straight line of the central shaft that is connected charging wire 41 and photoreceptor 3 of the correctly saying so) maximum that is the photosensitive surface current potential at the position relative with charging wire 41 with the distribution of Gauss's shape, diminish between each straight line.

And as shown in figure 12, when the order hole of grid electrode 43Z changed, the state of distribution did not change, but the level change of drum electric current, order hole thick more (slit is wide big more), the level of drum electric current is big more.That is, so, by changing the order hole of grid electrode, even identical by the magnitude of current of charging wire 41 discharges, also can make photosensitive surface charged is different states.

When the order hole is thick, adjust towards the throughput of the discharge current of photoreceptor 3, make current potential evenly and the effect that is stabilized to predetermined potential reduce.But, because the throughput of discharge current is bigger, therefore can apply sufficient electric current to photoreceptor 3 surfaces, can make photoreceptor 3 surfaces charged at short notice.

On the contrary, when the order hole was closeer, the throughput of discharge current was less, can't make photoreceptor 3 charged at short notice.But, can suitably control the throughput of discharge current, make the surface potential of photoreceptor 3 even, and be stabilized in and set on the charged current potential.

When above-mentioned Charging system 4B carries at image display device, as shown in figure 14, with respect to photoreceptor 3, making the direction vertical with the sense of rotation (arrow X) of photoreceptor 3 is length direction, among the grid electrode 43B thick regional 52 is positioned at sense of rotation upstream one side of photoreceptor 3, and close regional 53 are positioned at sense of rotation downstream one side.

And, when making photoreceptor 3 charged, the voltage that applies about 4KV～6KV to charging wire 41,41, and apply the bias voltage corresponding with the charged current potential of required photoreceptor 3 to grid electrode 43B.In addition, apply the differences such as toner polarity of the polarity of voltage because of visualization way, use.

On the other hand, photoreceptor 3 is driven in rotation and makes its surface relative with Charging system 4B.Photoreceptor 3 is by the apply zone relative with Charging system 4B, thereby makes surface charging arrive the charged current potential of determining in advance of setting (predetermined potential).

As mentioned above, be provided with thick regional 52 and close regional 53, thick regional 52 and be positioned at sense of rotation upstream one side of photoreceptor 3 in grid electrode 43B, close regional 53 are positioned at sense of rotation downstream one side.

Therefore, the surface of photoreceptor 3 with pass through at first thick regional 52 relative during, set near the value charged current potential near (slightly charged).Afterwards, the surface of photoreceptor 3 with the next one pass through close regional 53 relative during, finish thick charged surface potential and for the grid current potential the charged original charged ability of grid electrode arranged by stable and uniform is charged, charged equably is the charged current potential of above-mentioned setting, and stabilization (adjusting charged).

So, charged function is separated into: the surface potential that makes photoreceptor 3 is slightly charged near near the value of setting charged current potential, and make near the surface potential homogenising of close this value and stabilize to the adjustment of setting charged current potential charged, by charged in a plurality of stages, the further high speed of the peripheral speed of photoreceptor 3, when as present embodiment, being 600mm/sec, also can do one's utmost to suppress to make photoreceptor charged uniformly and stably under the state that ozone growing amount and image processing system maximize to predetermined potential.

And thick regional 52 among grid electrode 43B and close regional 53 order hole are suitably set according to the peripheral speed of the photoreceptor of the image processing system that carries and are got final product, and do not have a fixed pattern.Even corresponding, can change according to material, the thickness of grid electrode 43B with same peripheral speed.

And thick regional 52 among grid electrode B and close regional 53 boundary position dispose many charging wires 41 as shown in figure 12, when having valley in the drum electric current, and preferably corresponding configuration with this valley.In drum electric current little valley part, make the charged ability of photoreceptor 3 a little less than, even therefore thick zone 52 and close regional 53 border deviation slightly also can reduce the influence to the electriferous state of photoreceptor 3, it is easy that charged control becomes.

And, when charging wire 41 is one, making close regional 53 greater than thick zone 52, the peak value of drum electric current partly enters into close regional 53, thereby can carry out more stable charged.This be because, the charged ability in thick zone 52 can slightly be improved by making the order hole, even but the charged ability of close regional 53 adjustment slightly also can not improve the order hole, need the time.

Further, in this illustration respectively have grid electrode 43B one close regional 53 and thick zone 52, that constitute by two zones, but also can make sense of rotation upstream one side from photoreceptor 3 to the downstream one side, the order hole with a plurality of stages from slightly to close variation.

And grid electrode 43B is provided with thick zone and close zone and has at one and realizes thick electro-mechanical part in the charged device of grid electrode and adjust electro-mechanical part under this structure, even separated the structure of charged function, also to have the effect that can avoid Charging system to maximize.

In addition, thick electro-mechanical part can utilize different charged devices to constitute with the adjustment electro-mechanical part, but the also appropriate combination setting of charged mode.For example as shown in figure 16, also following Charging system 63: constitute thick electro-mechanical part by the charged device 60 of no grid electrode, adjust electro-mechanical part and utilize the charged device 61 of contact electrification mode (utilizing charged roller among the figure) to carry out.

The control of charged current potential is more or less freely in the charged mode of contact-type, and can make charged current potential stabilization, is applicable to that therefore purpose is to make surface charge evenly and be stabilized in the adjustment electro-mechanical part of predetermined potential.Certainly, slightly electro-mechanical part also can utilize the contact electrification mode to constitute.

And, the charged control that is unsuitable for charged current potential of no grid electrode, though therefore be unsuitable for adjusting electro-mechanical part, charged ability is higher, can improve the surface potential of photoreceptor 3 at short notice, is suitable for thick electro-mechanical part.Therefore, when thick electro-mechanical part is no grid electrode when charged, adjust electro-mechanical part and use and have grid electrode charged, Charging system 62 as shown in figure 17, but its only constitute also with the part configuration grid electrode 43X of the sense of rotation downstream one side butt of a photoreceptor 3 that gate strip electrical equipment arranged.

(embodiment 1)

In present embodiment 1, grid electrode 43B uses that wide (slit separation 2.55mm～2.57mm), close regional 53 slit are wide, and (slit separation is 1.55～1.57mm) electrode as 1.4mm as 2.4mm with the wide slit as 0.15mm～0.17mm (error of 0.16mm ± 0.01mm), thick zone 52 of the electrode wires between slit.

And the peripheral speed of photoreceptor 3 is 600mm/sec, the voltage (grid current potential) that is applied to grid electrode 43B for as the charged current potential of setting (target current potential) of drum surface potential 650 (V).And charging wire 41,41 uses the tungsten line of Φ 60 μ, and electrode is shared.Under this condition, the electric wire electric current is changed in 300 (μ A)～900 (μ A), measure the drum surface potential.

And, as a comparative example, use the grid electrode of the wide and slit separation single pattern of homogeneous in Zone Full of slit, except the order hole difference of grid electrode, all under the condition identical, carry out same bulging surface potential detection with embodiment.The slit of comparative example 1 is wide to be that (slit separation 1.55mm～1.57mm), the slit of comparative example 2 is wide to be 1.8mm to 1.4mm.

Figure 15 represents measurement result.And in Figure 15, transverse axis is represented the electric wire electric current, and the longitudinal axis is represented the drum surface potential.As shown in figure 15, in embodiment and comparative example, all along with the increase of electric wire electric current, the drum surface potential rises.And in an embodiment, along with close 900 (the μ A) of electric wire electric current, the drum surface potential (V), reaches 650 (V) near 650 when 900 (μ A).

That is, in embodiment 1, can obtain to set charged current potential or approaching with it current potential, and when the electric wire electric current is high electric current, also can surpass and set charged current potential.That is, realized in high-speed equipment that as can be known stablizing of photoreceptor 3 is charged.

Relative with it, in comparative example 1, when flowing into the high electric current of 900 (μ A) as the electric wire electric current, the drum surface potential also only rises to 615, and (V), charged current potential is set in no show.That is it is charged, photoreceptor 3 to be stablized.And in comparative example 2, when the electric wire electric current became 700 (μ A), the drum surface potential became 653 and (V), surpasses the grid current potential, can't carry out stable charged control.

As mentioned above, the Charging system that the present invention relates to carries on electro-photography apparatus, be to make the Charging system of the surface charging of the electrostatic latent image image-carrier that is driven and rotates to predetermined potential, it has: thick electro-mechanical part makes the surface charging of above-mentioned electrostatic latent image image-carrier reach near the value of above-mentioned predetermined potential; Adjust electro-mechanical part, the surperficial uniform charged that makes above-mentioned electrostatic latent image image-carrier charged in this thick electro-mechanical part is to above-mentioned predetermined potential.

And, above-mentioned adjustment electro-mechanical part can be by there being the charged device of grid electrode to constitute, and this has the charged utensil of grid electrode to have: electric wire, on the position relative with the electrostatic latent image image-carrier, with the direction vertical with the sense of rotation of this electrostatic latent image image-carrier is the direction of principal axis configuration, and is applied in high voltage; Guarded electrode shields this electric wire, opens and the relative face of above-mentioned electrostatic latent image image-carrier; By the grid electrode that grid mesh part constitutes, be configured on the face of opening of this guarded electrode.

As mentioned above, the charged current potential excellent in uniform of the charged device of grid electrode is arranged, can make charged current potential stabilization, therefore be applicable to so that surface charge evenly and be stabilized in the adjustment electro-mechanical part that predetermined potential is a purpose.

Further, above-mentioned adjustment electro-mechanical part can be made of the charged device of the contact-type with contact components such as charged roller or charged brushes.

The control of the charged current potential of the charged device of contact-type is easier to, and can make charged current potential stabilization, therefore be applicable to so that surface charge evenly and be stabilized in the adjustment electro-mechanical part that predetermined potential is a purpose.

(the 3rd embodiment)

With reference to Fig. 3, Figure 18 to Figure 23 an embodiment of the invention are carried out following explanation.In addition for convenience of explanation, the parts to the parts identical function that has and use in first, second embodiment are marked with identical mark and omit its explanation.

Fig. 3 represents to carry the one-piece construction as the image processing system of the Charging system 4C of present embodiment.This image processing system substitutes Charging system 4A with Charging system 4C, is the main difference point with the image display device of first embodiment.4C also improves to Charging system, makes it can not cause image processing system to maximize and can make the photoreceptor 3 surperficial uniform chargeds of high speed rotating.

Charging system 4C to present embodiment is elaborated.The structure of the above-mentioned Charging system 4C of Figure 20 (a) Figure 20 (b) expression.In addition, Figure 20 (b) is that A-A alignment among Figure 20 (a) is looked sectional view.

Charging system 4C has: charging wire 41, charging case 42, grid electrode 43C.And the characteristic structure of Charging system 4C of the present invention is to have a charging wire.

Grid electrode 43C is the electric conductivity grid mesh part with a plurality of openings, and is the same with grid electrode 43A, 43B, is configured on the face of the opening in the above-mentioned charging case 42, and is applied in the bias voltage different with charging wire 41.Also apply the voltage identical at this by 45 couples of grid electrode 43C of electrode with charging case 42.In addition, also can make grid electrode 43B and charging case 42 insulation, apply different voltage respectively to it.

Grid electrode 43C is the same with grid electrode 43A, 43B, has the polygonal opening 51 shown in the slit 50 shown in Figure 18 (a) Figure 18 (b), Figure 19 (a) Figure 19 (b) etc.

And grid electrode 43C is the same with grid electrode 43B, have the order hole thick thick regional 52, and the order hole close close regional 53.

Particularly, grid electrode 43C shown in Figure 18 (a) is set at, the wide of electrode wires between slit is 0.15mm～0.17mm (error of 0.16mm ± 0.01mm), the wide SW of slit in the thick zone 52 is that (slit separation SP is 2.55mm～2.57mm) to 2.4mm, and the slit in close regional 53 is wide, and (slit separation SP is 1.55mm～1.57mm) for 1.4mm.

Here the object lesson in the order hole of the grid electrode 43C of example only is an example, and the present invention is not limited by this.For example, when the electrode wires between slit wide is 0.15mm～0.17mm (error of 0.16mm ± 0.01mm), (slit separation SP is 2.15mm～2.77mm), and the slit in close regional 53 is wide, and (slit separation SP is 1.35mm～1.77mm) for 1.2mm～1.6mm also the wide SW of slit in thick zone 52 can be set at 2.0mm～2.6mm.

And, in the grid electrode 43C shown in Figure 19 (a), the wide of electrode wires between slit is 0.25mm～0.27mm (error of 0.26mm ± 0.01mm), external diameter of a circle HW in the thick zone 52 is that (the spacing HP of circumscribed circle is 4.5mm～4.52mm) to 4.25mm, and the external diameter of a circle HW in close regional 53 is that (the spacing HP of circumscribed circle is 4.0mm～4.02mm) to 3.75mm.

Even and in the grid electrode 43C shown in Figure 19 (a), the object lesson in the order hole of illustrative gate electrode 43 also only is an example, the present invention is not limited by this.For example, when the electrode wires between slit wide is 0.25mm～0.27mm (error of 0.26mm ± 0.01mm), (the spacing HP of circumscribed circle is 4.25mm～4.77mm), and close regional 53 external diameter of a circle HW is that (the spacing HP of circumscribed circle is 3.75mm～4.27mm) to 3.5mm～4.0mm can to establish thick regional 52 external diameter of a circle HW and be 4.0mm～4.5mm.

Promptly, under any one situation of Figure 18 (a) and Figure 19 (a), form the wide basic identical of the wide electrode wires of slit, thick zone 52 is compared with close regional 53, the area of slit 50 (polygonal opening 51) is bigger, and the number of the slit 50 that exists under the unit area (polygonal opening 51) is less.On the other hand, close regional 53 compare with thick zone 52, and the area of slit 50 (polygonal opening 51) is less, and the number of the slit 50 that exists under the unit area (polygonal opening 51) is more.

And when making photoreceptor 3 charged, when the charging wire 41 to Charging system 4C applied voltage, each charging wire 41 made photoreceptor 3 surface chargings because of corona discharge, and electric current flows to photoreceptor 3 surfaces.This electric current is called " drum electric current ".

The surface potential of photoreceptor 3 is also different according to the different powers in position.Represent this power different be distributed as the photosensitive surface Potential distribution.The value of drum electric current becomes the current value corresponding with the strength distribution of photosensitive surface current potential.That is the distribution of the power of expression drum electric current, (distribution of drum electric current) is corresponding with the distribution (distribution of photosensitive surface current potential) of the power of expression photosensitive surface current potential.Therefore, in the big part of photosensitive surface current potential, the value of drum electric current becomes big, and in the little part of photosensitive surface current potential, the value of drum electric current diminishes.

In the photosensitive surface current potential, connect the photosensitive surface current potential maximum on the straight line of central shaft of charging wire and photoreceptor, along with away from this straight line, the photosensitive surface current potential diminishes.That is, the distribution of photosensitive surface current potential is the distribution that has peak value on the photosensitive surface on the straight line of the central shaft that connects charging wire and photoreceptor.

The grid electrode 43C of above-mentioned Charging system 4C is configured to: thick zone 52 and close regional 53 border dispose than the peak value of above-mentioned photosensitive surface current potential sense of rotation upstream one side near photoreceptor.That is, connecting the straight line configuration of the above-mentioned border and the central shaft of photoreceptor 3 must be than the straight line of the central shaft that is connected charging wire and photoreceptor sense of rotation upstream one side near photoreceptor.

At this, the distribution of the bulging electric current (photosensitive surface current potential) of photoreceptor 3 surface flow is described.Figure 21 is the chart that the bulging current's intensity of photoreceptor 3 surface flow of expression when charging wire 41 applies voltage distributes.And in Figure 21, enumerated and used the order hole that does not have thick zone, close zone to have the situation of grid electrode 43Z (with reference to Figure 21) of the slit of single pattern.And,, use wide three kinds of different (0.6mm, 1.2mm, the 2.4mm) grid electrodes of slit as grid electrode.

When the length of photoreceptor shown in Figure 21 represents that the point on the pairing photoreceptor of the central part part of charging wire (configuration) with Charging system is 0.0mm, to sense of rotation downstream one side of photoreceptor 3, the distance of upstream one side, one side is-30.0mm～30.0mm to the upstream from sense of rotation downstream one side of photoreceptor 3.

As shown in figure 21, under the situation of using any one grid electrode, the distribution of drum electric current is the distribution with peak value (maximal value).Figure 22 represents to rouse the synoptic diagram that the current's intensity distribution projects to the part of photoreceptor length correspondence.Illustrated bulging current's intensity to distribute 54 among Figure 22.As Figure 21 and shown in Figure 22, the peak of drum electric current is the pairing position of part that is provided with charging wire 41 (being positioned at the position of the photosensitive surface on the straight line of the central shaft that connects charging wire 41 and photoreceptor 3).

And distribute as can be known from this, slit is wide big more, and the drum electric current is big more.Even and when changing slit separation, the peak of distribution is also basic identical.Hence one can see that, even when changing slit separation, though there is difference in the peak value size, distribution shape is basic identical.

Therefore, when use had the grid electrode in two different zones of slit separation (thick zone and close zone), peak and distribution shown in Figure 21 were basic identical, and the size of drum electric current is separation and difference with the border in zone.

And above-mentioned thick zone and close zone dispose successively from one side direction downstream, sense of rotation upstream, one side of photoreceptor.That is, grid electrode is with respect to the sense of rotation of photoreceptor, and thick area configurations is one side in the upstream, and close area configurations is one side in the downstream.By this configuration, can carry out thick charged charged successively with adjustment.In this case, can two the different adjustment of the magnitude of current that applies of stage.That is, in thick zone, can apply bulging electric current to a certain degree, can control charged by the fine setting of carrying out the magnitude of current in close zone.

Further, the grid electrode 43C of present embodiment is configured to, and the boundary position in its thick zone and close zone is than the position of sense of rotation upstream one side of the close photoreceptor 3 in the pairing position of the peak value of bulging electric current.In this case, can make the area of the area in thick zone greater than close zone.That is, and carry out thick charged zone and compare, adjust charged zone and become big.

So, make close zone, enlarge the zone carry out magnitude of current fine setting, thereby can carry out the charged adjustment that reaches predetermined potential more fully, can carry out stable charged greater than thick zone.

The boundary position in above-mentioned thick zone and close zone is so long as can make thick charged and adjust and chargedly get final product evenly, the above-mentioned thick charged surface potential that is used to make photoreceptor takes current potential to a certain degree to, and above-mentioned adjustment is charged to be used to make charged current potential to be in predetermined current potential.Under this position, can avoid charged deficiency in the high-speed equipment, charged surplus.

And the position on above-mentioned border can be considered that the peripheral speed of photoreceptor, the voltage that is applied to charging wire, photoreceptor should charged current potential wait suitably and set.For example, the border can be set, make 1/3 scope of sense of rotation upstream one side of photoreceptor be thick zone, the scope of downstream one side 2/3 is close zone.In this case, the part of one side 1/3 is carried out slightly chargedly in the upstream, and the part of one side 2/3 is adjusted chargedly in the downstream, can carry out thick charged and close charged evenly.

So, dispose thick zone and close zone, and the size that makes close zone makes the zone of adjusting charged usefulness greater than thick charging zone greater than the size in thick zone, thereby can realize even and stable charged by said sequence.

And above-mentioned Charging system 4C is length direction with respect to photoreceptor 3 with the direction vertical with the sense of rotation of photoreceptor 3, and a side that is provided with electrode 44,45 is disposed in the inboard of image processing system.

And, when making photoreceptor 3 charged, apply voltage about 4KV～6KV, and apply bias voltage with the charged current potential correspondence of photoreceptor 3 to grid electrode 43C to each charging wire 41.Wherein, the structure of grid electrode 43 be from the upstream one side direction downstream, one side have the order hole different thick regional 52 and close regional 53, therefore can not increase the ozone growing amount and image processing system is maximized, it is charged to predetermined potential that photoreceptor 3 is stablized.And, apply the differences such as toner polarity of the polarity of voltage because of visualization way, use.

The applicant has carried out various researchs to following content: have in the charged Charging system of grid electrode in use, apply the regional countermeasure with increase except enlarging the wide of charging case, can make the photoreceptor of high speed rotating stablize the charged predetermined potential that reaches.

Under study for action, use the image processing system that carries the electro-photography apparatus of Charging system 4B as predetermined, change condition, investigation flow through the relation of the electric current (hereinafter referred to as the electric wire electric current) of charging wire 41 and the surface potential of photoreceptor 3 (hereinafter referred to as the drum surface potential).And the upper limit of electric wire electric current is made as 900 (μ A).This is because when surpassing 900 (μ A), the ozone growing amount obviously increases.

In addition, the present invention has the grid electrode in thick zone and close zone by use, has realized stable chargedly, and has suppressed the increase of ozone growing amount.But, be that when use had the grid electrode in thick zone and close zone, the upcurve of drum surface potential became in desirable scope sharply under one the situation when charging wire, it is difficult that charged control becomes.Reference example when therefore simple method is used in charged control describes following.

(reference example)

In this reference example, used that slit is wide to be 2.4mm (slit separation 2.55mm～grid electrode 2.57mm), the wide 1.8mm of slit (slit separation 1.95mm～grid electrode 1.97mm), the wide 1.2mm of slit (slit separation 1.35mm～grid electrode 1.37mm), the wide 0.6mm of the slit (grid electrode of slit separation 0.75mm～0.77mm).

And in this reference example, the peripheral speed of photoreceptor is 600mm/s.And the voltage (grid current potential) that is applied to grid electrode is the 650V as the target current potential that rouses surface potential.And charging wire uses the tungsten line of Φ 60 μ, disposes one.Under this condition, the electric wire electric current is changed at 50 μ A～900 μ A, measure the drum surface potential.Its measurement result as shown in figure 23.

Figure 23 is the chart of the relation of expression electric wire electric current and drum surface potential.As shown in figure 23, along with the change of electric wire electric current in each grid electrode is big, the drum surface potential rises.

Wherein, in the grid electrode of the wide 1.8mm of slit, along with close 900 (the μ A) of electric wire electric current, the drum surface potential (V), arrives 650 (V) near target current potential 650 when 800 (μ A).That is, can obtain target current potential or approaching with it current potential, and when making the electric wire electric current be high electric current, also become 650 substantially (V).

On the other hand, slit is wide to be in the grid electrode of 2.4mm, and when the electric wire electric current became 750 μ A, the drum surface potential arrived 650V, when the electric wire electric current is 800 μ A, has surpassed target current potential 650V.

And, in the grid electrode of the grid electrode of the wide 0.6mm of slit and the wide 1.2mm of slit, even flow into the high electric current of electric wire electric current 900 (μ A), the drum surface potential also the miss the mark current potential 650V (V).

As mentioned above, the Charging system that the present invention relates to carries on electro-photography apparatus, make the predetermined current potential of surface band of the electrostatic latent image image-carrier that is driven in rotation, comprise: a wire, on the position relative with above-mentioned electrostatic latent image image-carrier, with the direction vertical with the sense of rotation of this electrostatic latent image image-carrier is the direction of principal axis configuration, and is applied in high voltage; Guarded electrode shields this electric wire, opens and the relative face of above-mentioned electrostatic latent image image-carrier; Cancellous grid electrode, be configured on the face of opening of above-mentioned guarded electrode, above-mentioned grid electrode has thick zone and the close zone that the order hole of mesh differs from one another, above-mentioned thick zone and close zone dispose successively from one side direction downstream, sense of rotation upstream, one side of electrostatic latent image image-carrier, and the border in above-mentioned thick zone and close zone is positioned at: the pairing position of distribution peak value of the surface potential intensity of the above-mentioned electrostatic latent image image-carrier of ratio expression is near the position of sense of rotation upstream one side of electrostatic latent image image-carrier.

Charging system of the present invention carries on electro-photography apparatus, makes the surface band predetermined potential of the electrostatic latent image image-carrier that is driven in rotation.This Charging system with the relative position of above-mentioned electrostatic latent image image-carrier on, be the direction of principal axis configuration with the direction vertical with the sense of rotation of electrostatic latent image image-carrier, have a wire, guarded electrode, and grid electrode.

Guarded electrode is used for shielding wire, open relative with electrostatic latent image image-carrier face.And electric wire carries out corona discharge by applying high pressure.Grid electrode is a mesh-shape, adjusts the current's intensity that flows into by this corona discharge.

And above-mentioned grid electrode has thick zone and the close zone that the order hole of mesh differs from one another.That is, this grid electrode has a plurality of peristomes (mesh), has peristome size, number, thick zone and close zone that density is different.

Wherein, thick zone is the big zone, the close zone of order boring ratio of grid mesh part, and close zone is little zone, the thick zone of the order boring ratio of mesh.Promptly, thick zone is compared with close zone, during the electrode wires between opening wide identical, the area of its opening is bigger, and the opening number that exists under the unit area is less, and close zone is compared with thick zone, during the electrode wires between opening wide identical, the area of its opening is less, and the opening number that exists under the unit area is more.But in thick zone and close zone, the wide of the electrode wires between opening may not be identical, and thick zone is meant the big and thicker state of order with respect to close regional opening size, and close zone is meant state less with respect to thick regional opening size and that order is closeer.

So, because grid electrode has thick zone and close zone, therefore carry out different electric current adjustment in each zone, charged control can be carried out according to each zone.

For example, in thick zone,, therefore the wire electrodischarge electric current is fully passed through because the order hole of mesh is bigger.Therefore can apply sufficient electric current to the electrostatic latent image image carrier surface, make the electrostatic latent image image-carrier fully charged.Below will in thick zone, carry out charged be called slightly charged.

On the other hand, in close zone, because the order hole of mesh is less, therefore can make the Current Control of wire electrodischarge is preferred value.Therefore can control the strength of current that is applied to the electrostatic latent image image carrier surface, make the charged preferred value that is controlled to be of electrostatic latent image image-carrier.Below will carry out in this close zone charged be called adjust charged.

And in Charging system of the present invention, above-mentioned thick zone and close zone dispose successively from one side direction downstream, sense of rotation upstream, one side of electrostatic latent image image-carrier.Therefore thick charged and adjust and chargedly carry out successively.

So, by having a plurality of zones that can make the adjustment that the strength of current that is applied to the electrostatic latent image image carrier surface changes, can carry out thick charged and adjust charged two kinds charged.And,, therefore for example under the situation of high-speed equipment, also can carry out more stable charged owing to carry out thick chargedly and adjust chargedly successively.

And, in Charging system of the present invention, use a wire, therefore represent that the distribution of the surface potential intensity of electrostatic latent image image-carrier becomes the distribution with a peak value.And in the Charging system of the present invention, the border in above-mentioned thick zone and close zone is positioned at sense of rotation upstream one side than the close electrostatic latent image image-carrier in the pairing position of peak value of the distribution of the intensity of the surface potential of expression electrostatic latent image image-carrier.

And,, flow through electric current (drum electric current) at the electrostatic latent image image carrier surface by making the electrostatic latent image image-carrier charged.The intensity distributions correspondence of the surface potential of this drum current's intensity distribution and electrostatic latent image image-carrier.That is, in the big part of the surface potential of electrostatic latent image image-carrier, the value of drum electric current becomes big, and in the little part of the surface potential of electrostatic latent image image-carrier, the value of drum electric current diminishes.Particularly, the peak value of the intensity distributions of the surface potential of electrostatic latent image image-carrier becomes the maximal value (peak value of drum electric current) of the value of bulging electric current.

Therefore, Charging system of the present invention also can show as: the border in thick zone and close zone is configured in sense of rotation upstream one side of the close electrostatic latent image image-carrier of peak value institute correspondence position that distributes than bulging current's intensity.

And, because the border in above-mentioned thick zone and close zone is positioned at the position of the pairing position of peak value of the intensity distributions (the drum current's intensity distributes) than the surface potential of electrostatic latent image image-carrier near sense of rotation upstream one side of electrostatic latent image image-carrier, therefore can make the size of the size in close zone greater than thick zone.In this case, to adjust charged zone bigger owing to can make, and therefore can realize stable charged.

So, the varying in size of size by making thick zone and close zone, and with each zone of above-mentioned arranged in order, thereby can be in each zone carry out with suitable order suitable charged.Therefore can not increase the growing amount of ozone, electro-photography apparatus is maximized, can in high-speed equipment, make the electrostatic latent image image-carrier charged to predetermined potential.

In the Charging system that the present invention relates to, above-mentioned grid electrode has a plurality of slits, the wide 2.0～2.6mm that is preferably of the slit in above-mentioned thick zone, and slit separation is 2.15～2.17mm, the slit in above-mentioned close zone is wide to be 1.2～1.6mm, and slit separation is 1.35～1.77mm.According to said structure, in high-speed equipment, can make the electrostatic latent image image-carrier charged to predetermined potential.

The Charging system that the present invention relates to, above-mentioned grid electrode has a plurality of polygonal openings, the external diameter of a circle external with the opening in above-mentioned thick zone is preferably 4.0～4.5mm, the spacing of circumscribed circle is 4.25～4.77mm, the external diameter of a circle external with the opening in above-mentioned close zone is 3.5～4.0mm, and the spacing of circumscribed circle is 3.75～4.27mm.According to said structure, in high-speed equipment, can make the electrostatic latent image image-carrier charged to predetermined potential.

In order to solve above-mentioned problem, the electro-photography apparatus that the present invention relates to has: the electrostatic latent image image-carrier forms electrostatic latent image and is driven in rotation on the surface; And Charging system, make the predetermined current potential of this electrostatic latent image image carrier surface band, wherein, above-mentioned Charging system has the charged device of grid electrode to constitute by one, this has the charged device of grid electrode to comprise: a wire, on the position relative, be the direction of principal axis configuration with the direction vertical, and be applied in high voltage with the sense of rotation of this electrostatic latent image image-carrier with above-mentioned electrostatic latent image image-carrier; Guarded electrode shields this electric wire, opens and the relative face of above-mentioned electrostatic latent image image-carrier; Cancellous grid electrode, be configured on the face of opening of this guarded electrode, above-mentioned grid electrode has thick zone and the close zone that the order hole of mesh differs from one another, above-mentioned thick zone and close zone dispose successively from one side direction downstream, sense of rotation upstream, one side of electrostatic latent image image-carrier, and the border in above-mentioned thick zone and close zone is positioned at: the pairing position of distribution peak value of the surface potential intensity of the above-mentioned electrostatic latent image image-carrier of ratio expression is near the position of sense of rotation upstream one side of electrostatic latent image image-carrier.

According to said structure,, can carry out stable charged as illustrated in Charging system.And, can not increase the growing amount of ozone, electro-photography apparatus is maximized, can in high-speed equipment, make the electrostatic latent image image-carrier charged to predetermined potential.

In the electro-photography apparatus that the present invention relates to, above-mentioned grid electrode has a plurality of slits, the wide 2.0～2.6mm that is preferably of the slit in above-mentioned thick zone, and slit separation is 2.15～2.17mm, the slit in above-mentioned close zone is wide to be 1.2～1.6mm, and slit separation is 1.35～1.77mm.And, in the electro-photography apparatus that the present invention relates to, above-mentioned grid electrode has a plurality of polygonal openings, the external diameter of a circle external with the opening in above-mentioned thick zone is preferably 4.0～4.5mm, the spacing of circumscribed circle is 4.25～4.77mm, the external diameter of a circle external with the opening in above-mentioned close zone is 3.5～4.0mm, and the spacing of circumscribed circle is 3.75～4.27mm.According to said structure, in high-speed equipment, can make the electrostatic latent image image-carrier charged to predetermined potential.

In the electro-photography apparatus that the present invention relates to, the peripheral speed of above-mentioned electrostatic latent image image-carrier is preferably more than the 400mm/sec.According to said structure, stable charged even above-mentioned electro-photography apparatus also can carry out when high-speed equipment.

In the electro-photography apparatus that the present invention relates to, the current potential that applies to above-mentioned grid electrode is preferably roughly the same with the current potential as the charged potential setting of electrostatic latent image image carrier surface.According to said structure, can make the electrostatic latent image image carrier surface band current potential identical with the current potential that is applied to grid electrode.

(the 4th embodiment)

With reference to Fig. 3, Figure 24 to Figure 29 an embodiment of the invention are carried out following explanation.In addition, for convenience of explanation, the parts of the parts identical function that has and use in first, second, third embodiment are marked with identical mark and omit its explanation.

Fig. 3 represents to carry the one-piece construction as the image processing system of the Charging system 4D of present embodiment.This image processing system substitutes Charging system 4A with Charging system 4D, is the main difference point with the image processing system of first embodiment.4D also improves to Charging system, makes it can not cause image processing system to maximize and can make the photoreceptor 3 surperficial uniform chargeds of high speed rotating.

Charging system 4D as present embodiment is elaborated.Figure 26 (a) Figure 26 (b) expression is as the structure of the Charging system 4D of present embodiment.Charging system 4D comprises charging wire 41, charging case 42, grid electrode 43D.

In Charging system 4D, be provided with two charging wires 41, apply identical voltage by electrode 44 to two charging wires 41,41.In addition, charging wire 41 is many and gets final product, and also can be more than three, and, also can apply different voltage to each charging wire 41,41.

Grid electrode 43D is the same with grid electrode 43A～43C, is configured on the face of opening of above-mentioned charging case 42, is applied in the bias voltage different with charging wire 41.At this, also apply the voltage the same to grid electrode 43D with charging case 42 by electrode 45.In addition, also can grid electrode 43 and charging case 42 insulation, apply different voltage respectively to it.

Grid electrode 43D is the electric conductivity grid mesh part with a plurality of openings, and 43B is the same with grid electrode, has the slit 50 shown in Figure 24 (a) Figure 24 (b), the polygonal opening 51 of Figure 25 (a) Figure 25 (b) etc.

And grid electrode 43C is the same with grid electrode 43B, 43C, have the order hole thick thick regional 25, and the order hole close close regional 53.

Particularly, grid electrode 43D shown in Figure 24 is set at, and the wide wide SW of slit for 0.15mm～0.17mm (error of 0.16mm ± 0.01mm), thick zone 52 of the electrode wires between slit is that (slit separation 2.55mm～2.57mm), close regional 53 slit are wide, and (slit separation is 1.55～1.57mm) to 2.4mm for 1.4mm.

Here the object lesson in the order hole of the grid electrode 43 of example only is an example, and the present invention is not limited by this.For example, when the electrode wires between slit wide is 0.15mm～0.17mm (error of 0.16mm ± 0.01mm), (slit separation SP is 2.15mm～2.77mm), and the wide SW of slit in close regional 53 is that (slit separation SP is 1.35mm～1.77mm) to 1.2mm～1.6mm also the wide SW of slit in thick zone 52 can be set at 2.0mm～2.6mm.

And, in the grid electrode 43 shown in Figure 25 (a), the wide of electrode wires between slit is 0.25mm～0.27mm (error of 0.26mm ± 0.01mm), external diameter of a circle HW in the thick zone 52 is that (the spacing HP of circumscribed circle is 4.5mm～4.52mm) to 4.25mm, and the external diameter of a circle HW in close regional 53 is that (the spacing HP of circumscribed circle is 4.0mm～4.02mm) to 3.75mm.

Even and in the grid electrode 43 shown in Figure 25 (a), the object lesson in the order hole of illustrative gate electrode 43 also only is an example, the present invention is not limited by this.For example, when the electrode wires between slit wide is 0.25mm～0.27mm, (the spacing HP of circumscribed circle is 4.25mm～4.77mm), and close regional 53 external diameter of a circle HW is that (the spacing HP of circumscribed circle is 3.75mm～4.27mm) to 3.5mm～4.0mm can to establish thick regional 52 external diameter of a circle HW and be 4.0mm～4.5mm.

Promptly, under any one situation of Figure 24 (a) and Figure 25 (a), form the wide basic identical of the wide electrode wires of slit, thick zone 52 is compared with close regional 53, the area of slit 50 (opening 51) is bigger, and the number of the slit 50 that exists under the unit area (opening 51) is less.On the other hand, close regional 53 compare with thick zone 52, and the area of slit 50 (opening 51) is less, and the number of the slit 50 that exists under the unit area (opening 51) is more.

And when making photoreceptor 3 charged, when the charging wire 41 to Charging system applied voltage, each charging wire 41 made photoreceptor 3 surface chargings because of corona discharge, and electric current flows to photoreceptor 3 surfaces.This electric current is called " drum electric current ".

The surface potential of photoreceptor 3 is also different according to the different powers in position.Represent this power different be distributed as the photosensitive surface Potential distribution.The value of drum electric current becomes the current value corresponding with the strength distribution of photosensitive surface current potential.That is the distribution of the power of expression drum electric current, (distribution of drum electric current) is corresponding with the distribution (distribution of photosensitive surface current potential) of the power of expression photosensitive surface current potential.Therefore, in the big part of photosensitive surface current potential, the value of drum electric current becomes big, and in the little part of photosensitive surface current potential, the value of drum electric current diminishes.

In the photosensitive surface current potential, connect the photosensitive surface current potential maximum on the straight line of central shaft of each charging wire and photoreceptor, along with away from this straight line, the photosensitive surface current potential diminishes.That is, the distribution of photosensitive surface current potential is the distribution that has peak value on the photosensitive surface on the straight line of the central shaft that connects each charging wire and photoreceptor, have valley between it.

The grid electrode of above-mentioned Charging system 4D is configured to: thick zone 52 and close regional 53 border are positioned at the less part of above-mentioned photosensitive surface current potential.That is, the straight line configuration that connects the central shaft of above-mentioned border and photoreceptor 3 must be between the straight line of the central shaft that connects two charging wires and photoreceptor, preferred disposition with the position of the valley correspondence of photosensitive surface current potential on.

At this, the distribution of photoreceptor 3 surfaces being gone up the bulging electric current (photosensitive surface current potential) that flows describes.Figure 27 is that the chart of the bulging current's intensity distribution of flowing is gone up on photoreceptor 3 surfaces of expression when charging wire 41 applies voltage.And in Figure 27, enumerated the situation when using the order hole that does not have thick zone, close zone to have the grid electrode of slit of single pattern.And, use wide three kinds of different (0.6mm, 1.2mm, the 2.4mm) grid electrodes of slit as grid electrode.

When the length of photoreceptor shown in Figure 27 represents that the point on the pairing photoreceptor of central part (middle body between each charging wire) with Charging system is 0.0mm, to sense of rotation downstream one side of photoreceptor 3, the distance of upstream one side, one side is-30.0mm～30.0mm to the upstream from sense of rotation downstream one side of photoreceptor 3.

As shown in figure 27, using under the situation of any one grid electrode, the distribution of drum electric current be have two peak values (maximal value), the distribution of a valley (minimum value).Figure 28 represents to rouse the synoptic diagram that the current's intensity distribution projects to the part of photoreceptor length correspondence.Illustrated bulging current's intensity to distribute 54 among Figure 28.As Figure 27 and shown in Figure 28, the peak of drum electric current is the pairing position of part that is provided with charging wire (being positioned at the position of the photosensitive surface on the straight line of the central shaft that connects charging wire and photoreceptor), the valley position of drum electric current than and two charging wires between the position (connecting the middle body between the straight line of central shaft of each charging wire and photoreceptor) of middle body correspondence slightly near the position of upstream one side.

And distribute as can be known from this, slit is wide big more, and the drum electric current is big more.Even and when changing slit separation, the peak of distribution, valley position are also basic identical.Hence one can see that, even when changing slit separation, though there is difference in the peak value size, distribution shape is basic identical.

Therefore, when use had the grid electrode in two different zones of slit separation (thick zone and close zone), peak and valley position and distribution shown in Figure 27 were basic identical, and the size of drum electric current is different distributions because of the peak value difference.

Further, the grid electrode of the present embodiment boundary position that is configured to its thick zone and close zone is positioned at and rouses the position of the valley correspondence of electric current.In this case, in the distribution of drum electric current, seize on both sides by the arms in two zones of valley, can flow into the bulging electric current of different sizes.That is, basic identical with the valley position of the distribution of drum electric current by the border that makes thick zone and close zone, each peak value of the bulging electric current that the corona discharge of each electric wire produces is corresponding with each thick zone and close zone.Therefore can change thick charged and adjust charged in the less part of drum electric current.

The less part (valley part) of drum electric current, because it is it is less to flow into the current value of photosensitive surface, therefore less to the charged effect of photoreceptor.On the other hand, the big part (peak value part) of drum electric current is because it is bigger to flow into the current value of photosensitive surface, therefore bigger to the charged effect of photoreceptor.That is, when the border that makes thick zone and close zone near the peak value of drum electric current near the time, the border varied slightly, the photosensitive surface value of current flowing will significantly change, and is difficult to carry out stable charged.Relative with it, when the border that makes thick zone and close zone near the valley of drum electric current near the time, even how many borders changes, the variable quantity of photosensitive surface value of current flowing is less, can carry out stable charged.Therefore charged control becomes easy.

And grid electrode is configured to, and with respect to the sense of rotation of photoreceptor, thick zone is one side in the upstream, and close area configurations is one side in the downstream.By this configuration, can carry out thick charged charged successively with adjustment.In this case, can be in the different adjustment of the magnitude of current that two stages apply.That is, under thick zone, apply bulging electric current to a certain degree, the fine setting of the magnitude of current that under close zone, applies, thus may command is charged.Consequently, in high-speed equipment, can avoid charged deficiency, superfluous charged.

And above-mentioned Charging system 4D is configured to, and with respect to photoreceptor 3, is length direction with the direction vertical with the sense of rotation of photoreceptor 3, a side that is provided with electrode 44,45 is configured in the inboard of image processing system.And, when making photoreceptor 3 charged, apply voltage about 4KV～6KV, and apply bias voltage with the charged current potential correspondence of photoreceptor 3 to grid electrode 43 to each charging wire 41.Wherein, since the structure of grid electrode 43 be from the upstream one side direction downstream, one side have the order hole different thick regional 52 and close regional 53, therefore can not increase the ozone growing amount, image processing system is maximized, it is charged to predetermined potential that sensitization 3 is stablized.And, apply the differences such as polarity of the polarity of voltage because of the toner of visualization way, use.

And when charging wire is 3 when above, the distribution of drum electric current becomes and has with the peak value of charging wire radical same number, and lacks the distribution of one valley than this peak value number.In this case, the boundary position in the thick zone of grid electrode and close zone so long as and the position of any one valley correspondence get final product.Wherein, the size in close zone is preferred and slightly zone big or small identical, or bigger.

That is, when the peak value number was even number, the border in thick zone and close zone was preferably placed at and the valley of central authorities or the position near the valley correspondence of upstream one side of comparing.And when the peak value number was odd number, the border in thick zone and close zone was preferably placed at and compares the position of the valley correspondence of the close upstream of central valley one side.

So, the size in close zone is big or small identical, perhaps bigger with thick zone, thereby can enlarge the zone of adjusting charged usefulness, so can carry out comparatively stable charged.

And, in the present embodiment, apply identical voltage to a plurality of electric wires, but the invention is not restricted to this, also can apply different voltage to a plurality of electric wires.

The applicant has carried out various researchs to following content: have in the charged Charging system of grid electrode in use, apply the regional countermeasure with increase except enlarging the wide of charging case, can make the photoreceptor of high speed rotating stablize the charged predetermined potential that reaches.

Under study for action, use the image processing system that carries the electro-photography apparatus of Charging system 4 as predetermined, change condition, investigation flow into the relation of the electric current (hereinafter referred to as the electric wire electric current) of charging wire and the surface potential of photoreceptor (hereinafter referred to as the drum surface potential).And the upper limit of electric wire electric current is made as 900 (μ A).This is because when surpassing 900 (μ A), the ozone growing amount obviously increases.Reaching comparative example by the following examples is specifically described.

(embodiment 1)

In the present embodiment, using the slit in thick zone as grid electrode, wide (slit in slit separation 2.55mm～2.57mm), close zone is wide, and (slit separation is 1.55～1.57mm) electrode as 1.4mm as 2.4mm.

And in the present embodiment, the peripheral speed of photoreceptor is 600mm/sec.The voltage (grid current potential) that is applied to grid electrode for as the target current potential of drum surface potential 650 (V).And charging wire uses the tungsten line of Φ 60 μ, disposes two.The electrode of each charging wire is shared.Under this condition, the electric wire electric current is changed in 300 (μ A)～900 (μ A), measure the drum surface potential.Its measurement result as shown in figure 29.

Figure 29 is the chart of the relation of expression electric wire electric current and drum surface potential.As shown in figure 29, along with electric wire electrorheological big drum surface potential rises.And along with close 900 (the μ A) of electric wire electric current, the drum surface potential (V), reaches 650 (V) near 650 of target current potential when 900 (μ A).That is, in the present embodiment, can obtain target current potential or approaching with it current potential, and when making the electric wire electric current be high electric current, also can not surpass as the target current potential 650 (V).That is, in high-speed equipment, can realize the charged of predetermined potential.

(comparative example 1)

In this comparative example, use the wide and slit separation grid electrode identical, so-called single pattern on whole of slit as grid electrode.And the slit of the grid electrode that uses in this comparative example is wide, and (slit separation is 1.55～1.57mm) as 1.4mm.

And in this comparative example, each condition such as the peripheral speed of photoreceptor, grid current potential, electric wire electric current and the foregoing description 1 are same condition, to measure bulging surface potential.Figure 29 represents this measurement result.

As shown in figure 29, in this comparative example, along with electric wire electrorheological big drum surface potential rises.But when the electric wire electric current had flowed into the high electric current of 900 (μ A), the drum surface potential only rose to 615 (V), miss the mark current potentials.That is, can't be charged to predetermined potential.

(comparative example 2)

In this comparative example, grid electrode also uses the electrode of single pattern.And the slit of the grid electrode that uses in this comparative example is wide to be 1.8mm (slit separation 1.95mm～1.97mm).And in this comparative example, each condition such as the peripheral speed of photoreceptor, grid current potential, electric wire electric current is the same with the foregoing description 1, thereby measures the drum surface potential.Figure 29 represents its measurement result.

As shown in figure 29, in this comparative example, along with electric wire electrorheological big drum surface potential rises.But when the electric wire electric current was 700 (μ A), the drum surface potential became 653 and (V), surpasses the target current potential.That is, can't be charged to predetermined potential.

Further, compare with the above-mentioned day disclosed Charging system of disclosure special permission communique " spy opens the 2000-137368 communique ", Charging system 4C, the 4D of present embodiment also have the charged effect that has good stability under the photoreceptor length direction except the effect of Miniaturizable.

That is, open in the structure of 2000-137368 communique above-mentioned spy, dispose a plurality of have a charging wire the grid electrode electro-mechanical part arranged, change the aperture opening ratio of each grid electrode.Under this structure, when toner is attached to the charging wire of the electro-mechanical part that charged ability is strong, aperture opening ratio is big, when chargeding performance is partly descended, no matter after the little electro-mechanical part of aperture opening ratio uniform charged how, on the length direction of photoreceptor also charged inequality can take place.

Relative with it, Charging system 4C, the 3D of present embodiment only has a charging case 42, in grid electrode 43C, the 43D that it has, makes its order hole (aperture opening ratio) different on the photoreceptor sense of rotation.

Therefore, even toner is attached to charging wire 41, chargeding performance partly descends, this bad grid electrode 43C, 43D homogenising with thick zone and close zone, the charged inequality on photoreceptor 3 surfaces is relaxed, and the charged stability on the photoreceptor length direction is higher.

In order to solve above-mentioned problem, the Charging system that the present invention relates to carries on electro-photography apparatus, make the predetermined current potential of surface band of the electrostatic latent image image-carrier that is driven and rotates, comprise: a plurality of electric wires, on the position relative with above-mentioned electrostatic latent image image-carrier, with the direction vertical with the sense of rotation of this electrostatic latent image image-carrier is the direction of principal axis configuration, and is applied in high voltage; Guarded electrode shields this electric wire, opens and the relative face of above-mentioned electrostatic latent image image-carrier; Cancellous grid electrode, be configured on the face of opening of above-mentioned guarded electrode, above-mentioned grid electrode has thick zone and the close zone that the order hole of mesh differs from one another, above-mentioned thick zone and close zone dispose successively from one side direction downstream, sense of rotation upstream, one side of electrostatic latent image image-carrier, and the border in above-mentioned thick zone and close zone is positioned at the pairing position of valley of the distribution of the surface potential intensity of representing above-mentioned electrostatic latent image image-carrier.

Charging system of the present invention carries on electro-photography apparatus, and the surface charging that is used to make the electrostatic latent image image-carrier that is driven and rotates is to predetermined potential.This Charging system with above-mentioned electrostatic latent image image-carrier relative position on, be direction of principal axis configuration with the direction vertical with the sense of rotation of electrostatic latent image image-carrier, have a plurality of electric wires, guarded electrode, grid electrode.

Guarded electrode is used to shield a plurality of electric wires, open relative with electrostatic latent image image-carrier face.And a plurality of electric wires carry out corona discharge by applying high voltage.Grid electrode is a mesh-shape, adjusts the current's intensity that flows by corona.

And above-mentioned grid electrode has thick zone and the close zone that mesh order hole differs from one another.That is, this grid electrode has a plurality of peristomes (mesh), has the different thick zone and the close zones of size, number, density of peristome.

Wherein, thick zone is the big zone, the close zone of order boring ratio of grid mesh part, and close zone is little zone, the thick zone of the order boring ratio of mesh.Promptly, thick zone is compared with close zone, during the electrode wires between opening wide identical, the area of its opening is bigger, and the opening number that exists under the unit area is less, and close zone is compared with thick zone, during the electrode wires between opening wide identical, the area of its opening is less, and the opening number that exists under the unit area is more.But in thick zone and close zone, the wide of the electrode wires between opening may not be identical, and thick zone is meant the big and thicker state of order with respect to close regional opening size, and close zone is meant state less with respect to thick regional opening size and that order is closeer.

So, because grid electrode has thick zone and close zone, therefore carry out different electric current adjustment in each zone, charged control can be carried out according to each zone.

For example, in thick zone,, therefore the wire electrodischarge electric current is fully passed through because the order hole of mesh is bigger.Therefore can apply sufficient electric current to the electrostatic latent image image carrier surface, make the electrostatic latent image image-carrier fully charged.Below will in thick zone, carry out charged be called slightly charged.

On the other hand, in close zone, because the order hole of mesh is less, therefore can make the Current Control of wire electrodischarge is preferred value.Therefore can control the strength of current that is applied to the electrostatic latent image image carrier surface, make the charged preferred value that is controlled to be of electrostatic latent image image-carrier.Below will carry out in this close zone charged be called adjust charged.

And in Charging system of the present invention, above-mentioned thick zone and close zone dispose successively from one side direction downstream, sense of rotation upstream, one side of electrostatic latent image image-carrier.Therefore thick charged and adjust and chargedly carry out successively.

So, by having a plurality of zones that can make the adjustment that the strength of current that is applied to the electrostatic latent image image carrier surface changes, can carry out thick charged and adjust charged two kinds charged.And,, therefore for example under the situation of high-speed equipment, also can carry out more stable charged owing to carry out thick chargedly and adjust chargedly successively.

And Charging system of the present invention uses many wires, so the intensity distributions of the surface potential of electrostatic latent image image-carrier has a plurality of peak values.In other words, there is valley in the intensity distributions of the surface potential of electrostatic latent image image-carrier.

And, by making the electrostatic latent image image-carrier charged, at electrostatic latent image image carrier surface inflow current (drum electric current).The intensity distributions correspondence of the surface potential of this drum current's intensity distribution and electrostatic latent image image-carrier.That is, in the big part of the surface potential of electrostatic latent image image-carrier, the value of drum electric current becomes big, and in the little part of the surface potential of electrostatic latent image image-carrier, the value of drum electric current diminishes.Particularly, the peak value of the intensity distributions of the surface potential of electrostatic latent image image-carrier becomes the maximal value (peak value of drum electric current) of the value of bulging electric current, and the valley of the intensity distributions of the surface potential of electrostatic latent image image-carrier becomes the minimum value (valley of drum electric current) of the value of bulging electric current.

Grid electrode of the present invention has following structure: the border in thick zone and close zone is positioned at the pairing position of valley (with the position of the valley correspondence of rousing electric current) of the distribution of the surface potential intensity of representing above-mentioned electrostatic latent image image-carrier.That is, its structure be the intensity distributions of the border in thick zone and the close zone surface potential that is configured in the electrostatic latent image image-carrier peak value, and adjacent with it peak value between the pairing position of valley part of the intensity distributions that exists.

As mentioned above, the peak value of drum electric current is the bigger part of electric current that flows on the electrostatic latent image image carrier surface, therefore helps the charged of electrostatic latent image image-carrier.Therefore, when near the peak value that the border in thick zone and close zone is set in bulging electric current, even the boundary position offset slightly, the electric current that flows on the electrostatic latent image image carrier surface also can take place changing, and is difficult to carry out stable charged.

On the other hand, the valley of drum electric current is the less part of electric current that flows at the electrostatic latent image image carrier surface, and is therefore less to the charged effect of electrostatic latent image image-carrier.Therefore, when near the valley that the border in thick zone and close zone is set in bulging electric current, even the boundary position offset slightly, the current change quantity that flows on the electrostatic latent image image carrier surface is less.Consequently can carry out stable chargedly, and charged control is easier to.

Therefore, can not increase the growing amount of ozone, image processing system is maximized, in high-speed equipment, can make the electrostatic latent image image-carrier charged to predetermined potential.

In the Charging system that the present invention relates to, the area in above-mentioned close zone is preferably greater than the area in thick zone.According to said structure, can enlarge and adjust charged zone, therefore can carry out stable charged efficiently.

In the Charging system that the present invention relates to, above-mentioned grid electrode has a plurality of slits, the wide 2.0～2.6mm that is preferably of the slit in above-mentioned thick zone, and slit separation is 2.15～2.17mm, the slit in above-mentioned close zone is wide to be 1.2～1.6mm, and slit separation is 1.35～1.77mm.According to said structure, in high-speed equipment, can make the electrostatic latent image image-carrier charged to predetermined potential.

The Charging system that the present invention relates to, above-mentioned grid electrode has a plurality of polygonal openings, the external diameter of a circle external with the opening in above-mentioned thick zone is preferably 4.0～4.5mm, the spacing of circumscribed circle is 4.25～4.77mm, the external diameter of a circle external with the opening in above-mentioned close zone is 3.5～4.0mm, and the spacing of circumscribed circle is 3.75～4.27mm.According to said structure, in high-speed equipment, can make the electrostatic latent image image-carrier charged to predetermined potential.

In order to solve above-mentioned problem, the electro-photography apparatus that the present invention relates to has: the electrostatic latent image image-carrier forms electrostatic latent image and is driven and rotates on the surface; Charging system, make the predetermined current potential of this electrostatic latent image image carrier surface band, wherein, above-mentioned Charging system has the charged device of grid electrode to constitute by one, this has the charged device of grid electrode to comprise: a plurality of electric wires, on the position relative, be the direction of principal axis configuration with the direction vertical, and be applied in high voltage with the sense of rotation of this electrostatic latent image image-carrier with above-mentioned electrostatic latent image image-carrier; Guarded electrode shields this electric wire, opens and the relative face of above-mentioned electrostatic latent image image-carrier; Cancellous grid electrode, be configured on the face of opening of this guarded electrode, above-mentioned grid electrode has thick zone and the close zone that the order hole of mesh differs from one another, above-mentioned thick zone and close zone dispose successively from one side direction downstream, sense of rotation upstream, one side of electrostatic latent image image-carrier, and the border in above-mentioned thick zone and close zone is positioned at the pairing position of valley of the distribution of the surface potential intensity of representing above-mentioned electrostatic latent image image-carrier.

According to said structure,, can carry out stable charged as illustrated in Charging system.And, can not increase the growing amount of ozone, electro-photography apparatus is maximized, can in high-speed equipment, make the electrostatic latent image image-carrier charged to predetermined potential.

In the electro-photography apparatus that the present invention relates to, the area in above-mentioned close zone is preferably greater than the area in thick zone.According to said structure, can enlarge and adjust charged zone, therefore can carry out stable charged efficiently.

In the electro-photography apparatus that the present invention relates to, above-mentioned grid electrode has a plurality of slits, the wide 2.0～2.6mm that is preferably of the slit in above-mentioned thick zone, and slit separation is 2.15～2.17mm, the slit in above-mentioned close zone is wide to be 1.2～1.6mm, and slit separation is 1.35～1.77mm.And, in the electro-photography apparatus that the present invention relates to, above-mentioned grid electrode has a plurality of polygonal openings, the external diameter of a circle external with the opening in above-mentioned thick zone is preferably 4.0～4.5mm, the spacing of circumscribed circle is 4.25～4.77mm, the external diameter of a circle external with the opening in above-mentioned close zone is 3.5～4.0mm, and the spacing of circumscribed circle is 3.75～4.27mm.According to said structure, in high-speed equipment, can make the electrostatic latent image image-carrier charged to predetermined potential.

In the electro-photography apparatus that the present invention relates to, the peripheral speed of above-mentioned electrostatic latent image image-carrier is preferably more than the 400mm/sec.According to said structure, stable charged even above-mentioned electro-photography apparatus also can carry out when high-speed equipment.

In the electro-photography apparatus that the present invention relates to, the current potential that applies to above-mentioned grid electrode is preferably roughly the same with the current potential as the charged potential setting of electrostatic latent image image carrier surface.According to said structure, can make the electrostatic latent image image carrier surface band current potential identical with the current potential that is applied to grid electrode.

(the 5th embodiment)

With reference to Figure 30 to Figure 44 an embodiment of the invention are carried out following explanation.In addition, for convenience of explanation, be marked with identical mark and omit its explanation having with the parts of the parts identical function that uses in the first embodiment.

Used the image processing system that carries the electro-photography apparatus of Charging system 4A as predetermined at this.Photoreceptor is the Organophotoreceptor of diameter 120mm.

Grid electrode uses that the thin plate to the thick 0.1mm that is made of SUS forms electrode wires between a plurality of slits widely is 0.15mm～0.17mm (error of 0.16mm ± 0.01mm), the wide 1.2mm of slit, 1.8mm, 2.4mm, four kinds of electrodes of 2.6mm.

Charging wire uses the tungsten line of Φ 60 μ, arranges two configurations on the sense of rotation of photoreceptor, and the electrode of two charging wires is shared.

Figure 30 represents: use the grid electrode of the wide 1.2mm of slit, change the voltage that applies to charging wire, the relation of the charged current potential (arrival current potential) of the photoreceptor when investigating the peripheral speed of photoreceptor and not applying grid voltage.

(V), (V) change, the peripheral speed of photoreceptor is 250mm/sec, 400mm/sec, 500mm/sec, 600mm/sec, 650mm/sec to the voltage that is applied to charging wire with 0.5K at 4.5K～6.5K.

Equally, Figure 31,32,33 represents respectively: use the grid electrode of the wide 1.8mm of slit, the grid electrode of the wide 2.4mm of slit, the grid electrode of the wide 2.6mm of slit respectively, the voltage that variation applies to charging wire, the relation of the charged current potential (arrival current potential) of the photoreceptor when investigating the peripheral speed of photoreceptor and not applying grid voltage.

According to the result who obtains, be applied to charging wire respectively apply voltage, be that (V), (V), (V), (V), 6.5K is (V) for 6.0K for 5.5K for 5.0K for 4.5K, the relation of the charged current potential (arrival current potential) of photoreceptor when drawing the peripheral speed of the wide photoreceptor of each slit and not applying grid voltage then becomes as Figure 34 to chart shown in Figure 38.

From Figure 34 to Figure 38 as can be known, the electrode of the wide 1.2mm of slit is that (V) time, be 400 o'clock in peripheral speed, also no show 650K is (V) for the charged current potential of photoreceptor for 6.0K applying voltage.Therefore, each data that when the wide 1.2mm of slit, obtains have been got rid of.And, (V) time,, judge that it is impracticable, therefore get rid of according to the ozone amount that produces when applying voltage 6.5K.

Figure 39 represents, making slit wide is 1.8mm, 2.4mm, 2.6mm, to charging wire apply voltage be mixed into 4.5K (V)～6.0K (V), the photoreceptor peripheral speed of each slit under wide and the relation of the charged current potential (arrival current potential) of the photoreceptor when not applying grid voltage.

And, therein, for the peripheral speed of photoreceptor be more than the 500mm/sec of high-speed equipment correspondence, the charged current potential of the photoreceptor of this moment is 650K (chart of scope V) (grid part among the figure), separately the lower limit and the upper limit are asked approximate expression, can obtain following formula 1:

(-A/7+760)＜E＜(A/5+810) ... formula 1

Wherein, A (mm/sec) is the peripheral speed of photoreceptor, and E is the charged current potential of photoreceptor that does not apply the state of grid voltage to grid electrode.

Promptly, the voltage that is applied to above-mentioned charging wire is that the peripheral speed of 5.0K (V)～6.0K (V), above-mentioned electrostatic latent image image-carrier is that 500mm/sec～600mm/sec, the thick 0.1mm of above-mentioned grid electrode, material are SUS, the wide 1.8mm～2.6mm of slit, the electrode wires between slit wide when being 0.16 (± 0.01) mm, and the arrival current potential that does not apply the photoreceptor under the state of grid voltage is in the scope shown in the formula 1.

Therefore, in the scope of 500mm/sec～600mm/sec, when the peripheral speed A of photoreceptor determines, according to formula 1, can try to achieve arrival current potential with the photoreceptor of peripheral speed A correspondence, therefore by grid voltage is set at below the minimum value that arrives current potential E, the charged current potential of photoreceptor can be controlled in grid electrode.

Equally, according to Figure 30 to result shown in Figure 33, when the photoreceptor peripheral speed is respectively 400mm/sec, 500mm/sec, 600mm/sec, 650mm/sec, drafting is applied to the relation of the charged current potential (arrival current potential) of the wide and photoreceptor when not applying grid voltage of the slit that respectively applies voltage of charging wire, becomes Figure 40 to chart shown in Figure 43.

And Figure 44 represents to be applied to the relation of the charged current potential (arrival current potential) that respectively applies the wide and photoreceptor when not applying grid voltage of slit in the voltage of charging wire.

Wherein, for more than the charged wide 1.8mm of slit with validity of high-speed equipment, the charged current potential of the photoreceptor of this moment be 650K (chart of scope V) (grid part among the figure), separately the lower limit and the upper limit are asked approximate expression, can obtain following formula 2:

(72B+520)＜E＜(75B+515) ... formula 2

Wherein, B (mm) is that the slit of grid electrode is wide, and E is the charged current potential that does not apply the photoreceptor under the grid voltage status to grid electrode.

Promptly, the voltage that is applied to above-mentioned charging wire is that the peripheral speed of 5.0K (V)～6.0K (V), above-mentioned electrostatic latent image image-carrier is that 500mm/sec～600mm/sec, the thick 0.1mm of above-mentioned grid electrode, material are SUS, the wide 1.8mm～2.6mm of slit, the electrode wires between slit wide when being 0.16 (± 0.01) mm, and the arrival current potential that does not apply the photoreceptor under the state of grid voltage is in the scope shown in the formula 2.

Therefore, 1.8mm in the scope of～2.6mm, when the wide B of the slit of grid electrode determines, according to formula 2, can try to achieve arrival current potential with the photoreceptor of the wide B correspondence of slit, therefore by grid voltage is set at below the minimum value that arrives current potential E, the charged current potential of photoreceptor can be controlled in grid electrode.

The embodiment of above-mentioned explanation and embodiment only are used for clear and definite technology contents of the present invention, must not be defined in its this concrete example and do narrow explanation, and purport of the present invention can be carried out various changes and enforcement as claimed in claim.

Claims (5)

1. a Charging system carries on electro-photography apparatus, makes the predetermined current potential of surface band of the electrostatic latent image image-carrier that is driven and rotates,

Comprise: electric wire on the position relative with above-mentioned electrostatic latent image image-carrier, is that direction of principal axis disposes with the direction vertical with the sense of rotation of this electrostatic latent image image-carrier, and is applied in high voltage;

Guarded electrode shields this electric wire, opens and the relative face of above-mentioned electrostatic latent image image-carrier; And

Cancellous grid electrode is configured on the face of opening of this guarded electrode,

Wherein, the order hole of above-mentioned grid electrode is set to: the slow more order of the peripheral speed of above-mentioned electrostatic latent image image-carrier hole is close more, and the fast more order of peripheral speed hole is thick more.

2. electro-photography apparatus has: the electrostatic latent image image-carrier forms electrostatic latent image and is driven and rotates on the surface; Charging system makes the predetermined current potential of this electrostatic latent image image carrier surface band, wherein,

Above-mentioned Charging system has the charged device of grid electrode to constitute by one, this has the charged device of grid electrode to comprise: electric wire, on the position relative, be the direction of principal axis configuration with the direction vertical, and be applied in high voltage with the sense of rotation of this electrostatic latent image image-carrier with above-mentioned electrostatic latent image image-carrier; Guarded electrode shields this electric wire, opens and the relative face of above-mentioned electrostatic latent image image-carrier; And cancellous grid electrode, be configured on the face of opening of this guarded electrode,

The order hole of above-mentioned grid electrode is set to: the slow more order of the peripheral speed of above-mentioned electrostatic latent image image-carrier hole is close more, and the fast more order of peripheral speed hole is thick more.

3. electro-photography apparatus according to claim 2, wherein,

The peripheral speed of above-mentioned electrostatic latent image image-carrier is 500mm/sec～600mm/sec,

Above-mentioned grid electrode has a plurality of slits, and the slit in this grid electrode is wide to be 1.8mm～2.4mm, and slit separation is 1.95mm～2.57mm.

4. electro-photography apparatus according to claim 2, wherein,

The peripheral speed of above-mentioned electrostatic latent image image-carrier is 500mm/sec～600mm/sec,

Above-mentioned grid electrode has a plurality of polygonal openings, and the diameter of a circle external with the polygon in this grid electrode is 3.5mm～4.5mm, and the spacing of circle is 3.75mm～4.75mm.

5. electro-photography apparatus according to claim 2, wherein,

The voltage that is applied to said wires is 5.0KV～6.0KV,

The peripheral speed 500mm/sec of above-mentioned electrostatic latent image image-carrier～600mm/sec,

Above-mentioned grid electrode is thick to be 0.1mm, and material is SUS, and slit is wide to be 1.8mm～2.6mm/sec, and the wide of the electrode wires between slit is 0.16 (± 0.01) mm.

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