JP2685658B2 - Transfer separation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer / separation device of an image forming apparatus for transferring a toner image formed on a photoconductor to a recording paper and electrically separating the recording paper from the photoconductor.

[0002]

2. Description of the Related Art In an image forming apparatus such as an electrophotographic copying machine or a laser printer, an electrostatic latent image formed on a photosensitive drum is usually developed with toner and the toner image is transferred onto a recording paper. By doing so, an image is formed. A transfer charger is usually used to transfer the toner image from the photosensitive drum to the recording paper.

As shown in FIG. 15, the conventional transfer charger is arranged below a photosensitive drum 30 which rotates in the direction of arrow A. The photosensitive drum 30 is rotated in the direction indicated by the arrow A in FIG. 15, and a toner image is formed on the photosensitive drum 30 by the time it reaches the area facing the transfer charger 81. The recording paper 50 is conveyed in the direction of arrow B,
It passes between the photosensitive drum 30 and the transfer charger 81. In the transfer charger 81, a charge wire 81b is stretched in a shield case 81a. By supplying electric power to the charge wire 81b to discharge the charge wire 81b, a charge image opposite to the toner image formed on the photosensitive drum 30 is obtained. A polar charge is applied to the recording paper 50. As a result, the toner image on the photosensitive drum 30 is transferred onto the recording paper 50.

The recording paper 50 to which the toner image has been transferred adheres to the photosensitive drum 30 and is conveyed. Therefore, the recording paper 50 serves as a recording paper discharging member in order to electrically separate the recording paper from the photosensitive drum 30. The static elimination brush 82 is disposed downstream of the transfer charger 81 in the recording paper conveyance direction.

As shown in FIG. 16, the recording paper discharging member is
For example, it is composed of a large number of electrically conductive static eliminating brushes 82, and is supported by an insulating holder 83 at appropriate intervals in the axial direction of the photosensitive drum 30. Static elimination brush 82
The leading end of each is in a non-contact state in which it is close to the recording paper 50, and each static elimination brush 82 is, for example, grounded so as to have a bias potential with respect to the charge wire 81b in the transfer charger 81.

The discharging brush 82 is designed to discharge the recording paper 50 by discharging the charging wire of the transfer charger 81 through the recording paper 50. A transport roller 84 and a transport belt 85 for transporting the recording paper 50 to the fixing device are provided on the downstream side of the static elimination brush 82 in the transport direction.

As the recording paper charge eliminating member, a conductor having a large number of saw-toothed portions having sharpened tips is arranged so that each sawtooth portion is arranged close to the recording paper 50. . In such a recording sheet transfer static eliminator, when power is supplied to the charge wire 81b of the transfer charger 81,
Electric currents flow through the photoconductor drum 30, the shield case 81a of the transfer charger 81, and the recording paper discharging member 82 such as a discharging brush.

[0008]

The charge wire 81b of the transfer charger 81 is usually supplied with electric power by a constant voltage transformer or a constant current transformer and is controlled by a constant voltage or a constant current.

Charge wire 81b of transfer charger 81
When a constant voltage is applied by a constant voltage transformer to the impedance change due to environmental changes,
The voltage applied to the charge wire 81a becomes constant.
As a result, the amount of charge used to transfer the toner image from the photosensitive drum 30 to the recording paper 50 varies, and the toner image may not be properly transferred to the recording paper 50.

When the electric power supplied to the charge wire 81b is controlled by a constant current, the electric charges used for transferring the toner image as well as the electric charges moving to the electric discharge brush 82, which is a recording paper electric discharge member, are included. It is controlled so as to have a constant current value. Therefore, the influence of the impedance change in the recording paper discharging member may affect the transfer effect of the toner image by the transfer charger 81 and the discharging effect of the recording paper by the recording paper discharging member.

Further, as described above, the static elimination brush 82 or the sawtooth static elimination member having a sharp tip is deformed by coming into contact with the recording paper, the cleaning tool, etc. at the time of paper jam processing or cleaning. There is a risk. When the static elimination brush 82 or the sawtooth static elimination member is deformed, the static elimination performance is deteriorated. The large number of static elimination brushes 82 are easily separated from the holder 83, and the separated static elimination brushes 82 may contact the charge wire 81b of the transfer charger 81 and leak.

The present invention solves such a problem, and its object is to prevent the transfer efficiency from the photosensitive member to the recording paper by the transfer charger to decrease due to environmental changes and the like. Another object of the present invention is to provide a transfer / separation device for an image forming apparatus, which is excellent in static elimination effect.

Another object of the present invention is to provide a transfer / separation device of an image forming apparatus which is less likely to be deformed even during cleaning or paper jam processing and which can prevent deterioration of charge removal performance.

[0014]

SUMMARY OF THE INVENTION A recording paper static eliminator of the present invention is an image forming apparatus for transferring a toner image formed on a photoconductor to a recording paper and then electrically separating the recording paper from the photoconductor. A transfer / separation device of the apparatus, the transfer charger transferring a toner image on a photoconductor onto a recording sheet by discharging a charge wire disposed in a shield case, and a transfer charger disposed downstream of the transfer charger in a recording sheet conveying direction. Set up and carry recording paper
Consists of a conductive thin plate extending in the direction orthogonal to the feeding direction
Recording on the side edge near the recording paper being conveyed
Provide an appropriate gap in the longitudinal direction on the side surface on the upstream side in the paper transport direction.
Multiple recesses arranged side by side so that the protruding parts are formed.
The recording sheet discharging member is provided, and the above object is achieved thereby.

Further , the recording paper static eliminator of the present invention is a photosensitive member.
After transferring the toner image formed on the recording paper,
The image forming apparatus that electrically separates the recording paper from the photoconductor
An image separation device that is installed in a shield case.
Record toner image on photoconductor by discharging wire
A transfer charger for transferring onto paper and the transfer charger
It is arranged on the downstream side of the recording paper conveyance direction, and is composed of a conductive thin plate extending in the direction orthogonal to the recording paper conveyance direction. The side edges close to the conveyed recording paper are spaced at appropriate intervals in the longitudinal direction. Covered with a high resistance material so that it is exposed .
Discharge of the charge wire in the transfer charger
Bias voltage so that current flows through the recording paper.
Is applied to the recording paper charge-eliminating member and the transfer charger
Transfer power supply means for supplying power to the charger wire,
It is supplied to the charge wire by the transfer power supply means.
Constant current, excluding the current flowing to the recording paper static elimination member
And means for controlling the
The goal is achieved.

Further , the recording paper static eliminator of the present invention is a photosensitive member.
After transferring the toner image formed on the recording paper,
The image forming apparatus that electrically separates the recording paper from the photoconductor
An image separation device that is installed in a shield case.
Record toner image on photoconductor by discharging wire
A transfer charger for transferring onto paper and the transfer charger
It is arranged on the downstream side of the recording paper conveyance direction and is composed of a conductive thin plate extending in the direction orthogonal to the recording paper conveyance direction. , A plurality of recesses are juxtaposed so that the protruding portions are formed at appropriate intervals in the longitudinal direction .
Discharge of the charge wire in the transfer charger
Bias voltage so that current flows through the recording paper.
Is applied to the recording paper charge-eliminating member and the transfer charger
Transfer power supply means for supplying power to the charger wire,
It is supplied to the charge wire by the transfer power supply means.
Constant current, excluding the current flowing to the recording paper static elimination member
And means for controlling the
The goal is achieved.

[0017]

In the transfer separation device of the image forming apparatus of the present invention, the current supplied to the charge wire of the transfer charger by the transfer power supply means is constant-current controlled except for the current flowing to the recording paper discharging member. , The current required to transfer the toner image on the photoconductor to the recording paper becomes constant,
There is no risk of defective transfer due to environmental changes.

[0018]

Embodiments of the present invention will be described below.

The transfer / separation device of the present invention is arranged below the photosensitive drum 30 in the image forming apparatus, as shown in FIG. The photoconductor drum 30 is adapted to rotate in the direction indicated by arrow A, and a toner image is formed on the peripheral surface during the rotation.

The toner image formed on the photoconductor drum 30 is transferred by the transfer charger 20 in the transfer separation device of the present invention onto the recording paper 50 which is conveyed on the guide plate 42 by the pair of registration rollers 41. . A recording paper discharging member 10 is arranged in parallel on the downstream side of the transfer charger 20 in the recording paper conveying direction, and the recording paper discharging member 10 discharges the recording paper 50 to which the toner image is transferred. Then, the recording paper 50 is
The conveyor belt 43 conveys the toner to a fixing device (not shown).

The transfer separation apparatus of the present invention is shown in FIGS.
As shown in FIG. 3, it has a shield case 21 arranged below the photosensitive drum 30, and a charge wire 22 stretched in the shield case 21. The shield case 21
Is a horizontal bottom surface portion 21b, a side wall portion 21c that is vertically continuous from one side portion of the bottom surface portion 21b, and a horizontal state from the upper end portion of the side wall portion 21c to the downstream side in the recording paper conveyance direction. It has a continuous flange portion 21d and has a substantially L-shaped cross section. On the bottom surface portion 21b of the shield case 21, a partition wall portion 23 is erected vertically above the side wall portion 21c with an appropriate interval, and the charge wire 22 is provided between the side wall portion 21c and the partition wall portion 21d.
Is stretched.

The charge wire 22 is a shield case 21.
Each wire holding member 27 disposed on each end of the bottom surface portion 22b in the above is erected in a state of having an appropriate tension. Each wire holding member 27 is configured separately from the side wall portion 21c and the bottom surface portion 22b of the shield case 21. Each wire holding member 27 includes a side plate 24 for closing each end face of the shield case 21 and a side plate.
The static eliminating member holder 25 is arranged vertically along the front end of the flange portion 21d of the shield case 21 so as to connect the 24 to each other, and is integrally formed of an insulating material. The lower end portion of the static eliminator holding member 25 is a holding portion 25a that horizontally extends to the downstream side in the recording paper conveyance direction,
A plate-shaped recording paper discharging member 10 is vertically supported on the holding portion 25a. The recording paper charge removing member 10 is a charge removing portion holder 25.
By the pressing member 26 held by the holding portion 25a, the pressing member 26 is pressed against the vertical portion of the static elimination member holder 25 and is held in the vertical state.

The plate-shaped charge removing member 10 is made of a conductive material, and its upper end is in a state of being appropriately spaced from the charge removing member holder 25 and the pressing member 26. The upper end portion of the recording paper discharging member 10 is in an exposed state.

A plurality of recording paper guide members 25b are arranged at the upper end of the static eliminator holder 25 at appropriate intervals in the axial direction of the photosensitive drum 30. Each recording paper guide member 25b is long in the recording paper conveyance direction, and prevents the conveyed recording paper 50 from advancing toward the upper end of the exposed recording paper static elimination member 10. Each recording paper guide member 25
b is also made of the same insulating material as the static elimination member holder 25 and is integrally formed with the static elimination member holder 25. Therefore, each recording paper guide member 25b is a wire holding member 24 of the transfer charger 20. It is integrated with both.

Shield case in the transfer charger 20
21 and the static eliminator holding tool 25 are supported by the support member 13. The support member 13 is a bottom portion of the shield case 21.
A horizontal portion 13a that holds 21b and a first vertical portion that is connected to one side portion of the horizontal portion 13a so as to extend upward and that holds the vertical portion of the static elimination member holder 25. Part 13
b, and a second vertical portion 13c continuously provided so as to extend downward from the horizontal portion 13a at a portion opposite to the first vertical portion. A lower end portion of a guide member 47 that conveys the recording paper 50 that is conveyed toward the photosensitive drum 30 is attached to the second vertical portion 13c.

Electric power is supplied to the charge wire 22 of the transfer charger 20 by a transfer transformer 28 which is a transfer power supply means, and the conductive charge removing member 10 is supplied with a charge removing transformer 11. The power is supplied and a constant bias voltage is applied. The current of the transfer transformer 28 is made constant by the constant current circuit 29.

An equivalent circuit of the transfer transformer 28 and the static elimination transformer 11 is shown in FIG. Electric current is generated by the discharge of the wire charger 22 and the photosensitive drum 30 and the shield case.
While flowing to the recording paper 21, it flows from the recording paper 50 to the recording paper discharging member 10. The impedance relating to the current flowing through the photosensitive drum 30 and the shield case 21 is indicated by Rt, and the impedance of the current flowing through the recording paper 50 to the charge eliminating member 10 is indicated by Rbc.

The current flowing through the discharging resistor RB of the static eliminator transformer is indicated by IB. Constant current circuit 29 for transfer
Controls the current (It-IB) flowing through the monitor resistor Ra to be constant. Also, IBC is resistance RBC
However, it does not flow to the monitor resistor Ra. Therefore, from the charge wire 22 to the photosensitive drum 3
0 and the current flowing to the shield case 21 are
Constant current control is performed by the constant current circuit 29 irrespective of the current IBC flowing through the recording paper discharging member 10 through 50.

In the image forming apparatus having such a configuration, the recording paper 50 is guided and conveyed by the guide plate 42 so as to come into contact with the pair of registration rollers 41. Then, the registration roller 41 is rotated in synchronization with the rotation of the photoconductor drum 30 on which the toner image is formed, and the recording paper 50 is conveyed to the photoconductor drum 30. When the recording paper 50 is conveyed to the upper area of the transfer charger 20, the charge wire of the transfer charger 20 is transferred.
A predetermined power is supplied to the transfer transformer 28 from the transfer transformer 28, and a predetermined bias voltage is applied to the recording paper charge removing member 10 by the charge removing transformer 11.

Charge wire 22 by transfer transformer 28
When a voltage is applied to the charge wire 22, the charge wire 22 is corona-discharged, and a current flows from the charge wire 22 to the photoconductor drum 30 and the shield case 21.
An electric current flows through the recording paper discharging member 10 through 50. And
The toner image on the photoconductor drum 30 is transferred onto the recording paper 50 by the current from the charge wire 22 to the photoconductor drum 30 and the shield case 21. At the same time, the static electricity on the recording paper 50 flows from the charge wire 22 to the static elimination member 10 to eliminate static electricity.

At this time, the current flowing from the charge wire 22 to the photosensitive drum 30 and the shield case 22 is set to a predetermined constant current by the constant current circuit 29. Therefore, even if a change in impedance due to a change in environment or a change in current flowing from the charge wire 22 through the recording paper 50 to the recording paper charge removing member 10 occurs, the current necessary for transferring the toner image is obtained, and The toner image is reliably transferred to.

The recording paper 50 to which the toner image has been transferred is separated from the photoconductor drum 30 by removing the static electricity by the recording paper discharging member 10, and is conveyed to the fixing device by the conveying belt 43.

In the above embodiment, the recording paper discharging member 1
A bias voltage is applied to 0 by the static elimination transformer 11, but for example, as shown in FIG. 4, a charging transformer 72 that supplies power to a charger wire 71a of a charger 71 that charges the photosensitive drum 30. Therefore, a bias voltage may be applied. In this case,
As long as the current flowing in the shield case 71b of the charging charger 71 is controlled by feeding back to the charging transformer 72, the bias voltage applied to the recording paper charge eliminating member 10 is the bias voltage of the charging charger 71. The same control as that for the output voltage is performed, and the recording paper 50 can be reliably neutralized. As described above, when the bias voltage to the recording paper discharging member 10 is applied by the charging transformer 72, it is more economical than the case where a constant current transformer is used alone. There is an advantage that a control circuit and a protection circuit for is unnecessary.

5 to 8 show another embodiment of the transfer charger and the recording paper discharging member. In this embodiment, as shown in FIG. 5, the transfer charger 61 includes a shield case 61a.
Is formed by bending a conductive thin plate into a box shape, and an opening is formed in a portion facing the upper photosensitive drum. A charge wire 61b is inserted through almost the center of the shield case 61a.
1b faces the photoconductor drum through the opening. The recording paper 50 is conveyed in a direction indicated by an arrow C orthogonal to the charge wire 61b.

As shown in FIG. 6, the recording paper discharging member 62 is made of a conductive thin plate, for example, a stainless thin plate having a thickness of about 0.05 to 0.2 mm. The recording paper static elimination member
62 is held by a holder 63 and is in a substantially vertical state so as to be orthogonal to the conveyance direction of the recording paper 50. The holder 63 is made of a high resistance material, and has a main body portion 63a for embedding a portion excluding the upper portion of the recording paper discharging member 62, and a pair extending in the longitudinal direction extending upward from the main body portion 63a. Each side edge portion 63b and a covering portion 63c that protrudes upward from the central portion of the side edge portions 63b from the main body portion 63a so as to cover the upper portion of the static elimination member 62. The covering portion 63c is provided with a large number of cutout portions 63d at appropriate intervals in the longitudinal direction so that the upper end portion of the recording paper discharging member 62 is exposed.

As shown in FIG. 7, each notch 63d is
The upper end portion of the recording paper discharging member 62 is exposed in a trapezoidal shape in which the length X of the upper side is shorter than the length Y of the lower side. With such a shape, the effect of discharging the recording paper 50 by the recording paper discharging member 62 is improved.

As described above, the charge eliminating member 62 is in the form of a thin plate extending in the direction orthogonal to the conveying direction of the recording paper 50, and the upper end of the notch 63d is provided at an appropriate interval in the longitudinal direction. Since it is covered with a high-resistance element except for, the recording sheet neutralizing member 62 when the sheet is jammed or cleaned.
Even if it receives an external force, it will not be deformed or damaged.
Further, when using the charge eliminating brush, there is a problem that a leak occurs due to the brush bristles coming off and coming into contact with the charge wire, but there is no such fear, and further, the recording paper charge eliminating member 62 is sharp. Since there is no special part, there is no danger of cutting hands.

The recording paper discharging member 62 is not limited to the method of partially exposing the recording paper discharging member 62 with a holder 63 made of a high resistance material. For example, as shown in FIG.
The recording paper discharging member 62 is covered with a high resistance film 64 having a window 64a so that the upper end of the recording paper discharging member 62 is exposed at a predetermined interval in the longitudinal direction, and is held by a predetermined holder. Good.

Still another embodiment of the recording paper discharging member is shown in FIG.
And FIG. The recording paper discharging member 65 of this embodiment is made of a conductive thin plate, for example, a stainless thin plate having a thickness of about 0.05 to 0.2 mm, and is held by a holder 66 except for the upper end portion thereof. The upper end portion of the recording paper discharging member 65 is located in the concave groove in the upper portion of the holder 66 and is exposed from the holder 66. On the side surface of the recording paper discharging member 65 near the recording paper 50 on the upstream side in the conveying direction of the recording paper 50, a large number of recesses are formed along the longitudinal direction.
65a are installed side by side. Each recess 65a is open to the upper end surface of the static elimination member 65, and has a triangular shape in which the width dimension is gradually reduced toward the lower side. Therefore, the space between the concave portions 65a is in a state of protruding toward the upstream side in the recording paper conveyance direction.

Each recess 65a is formed by half etching. The depth D of each recess 65a is equal to
The thickness E of 5 is set so as to satisfy the relationship of O.1 · E ≦ D ≦ 0.9 · E. Instead of such etching, half punching (half blanking) may be performed by precision pressing to form the recess 65a.

As described above, the thickness E of the recording paper discharging member 65 is set to about 0.05 to 0.2 mm, and the smaller the thickness E, the greater the effect of discharging.

In the recording paper discharging member 65 having such a structure,
The current from the charge wire 61b of the transfer charger 61 flows through the recording paper 50 to the protruding portion between the recesses 65a. Even with such a recording paper static elimination member 65, there is almost no possibility of deformation or damage, and a stable static elimination effect is exhibited.

The preferred specifications of the recording paper discharging member 65 of the embodiment shown in FIGS. 9 and 10 are shown below. However, it is assumed that it is applied to the photosensitive drum 30 having a drum diameter of 30 mm.

Material: SuS304-CSP Plate thickness t: 0.1 mm Step difference between the recessed portion 65a and other parts: Approx. 0.05 mm Processing method: Etching processing Applied voltage: Approx. 3.5 kV Static electricity removal current: Approx. 65 μA 11 and the experimental results of the present inventors shown in FIG. However, as for the processing method, etching processing was adopted due to its productivity.

FIG. 11 is a graph showing changes in the static elimination current (BCI _t ) when the material of the recording paper static elimination member 65 is changed.
However, in the graph, ○ indicates aluminum, × indicates stainless steel, and Δ indicates phosphor bronze.

As is clear from the graph, B is initially set.
Although there is no difference in CI _t , as the number of copies increases, phosphor bronze has a better BCI _t than aluminum or stainless steel.
It can be seen that there is little change in. Therefore, phosphor bronze is preferable only from this point of view, but stainless steel is most preferable from the viewpoint of cost and workability.

FIG. 12 is a graph showing the relationship between the applied voltage (BCV _k ) and BCI _t when the plate thickness t of the recording paper discharging member 65 made of the material SuS304-CSP is changed. However, Δ in the graph indicates that the recording paper static elimination member 65 having a plate thickness t of 0.15.
, × indicates 0.1, □ indicates 0.08, and □ indicates the recording sheet neutralizing member 65 of 0.05, respectively. The step is fixed at 1/2 of the plate thickness t.

As is clear from the graph, the thinner the plate thickness _t , the larger the BCI _t for the same BCV _k , and the better the static elimination effect. Therefore, if it is limited only to this point, it is preferable that the plate thickness t is 0.05. However, considering the manufacturing cost, workability, and serviceability (ease of handling) as well, the plate thickness is not practical. t
Is most preferably 0.1 mm.

Next, the difference in technical effect between the recording paper charge eliminating member 65 and the conventional saw blade charge eliminating member will be described with reference to FIGS. 13 and 14. Of these, Figure 13 shows BCI under high temperature and high humidity environment.
₅ is a graph showing the relationship between _t and transfer current (TCI _d ) and humidity. However, in the graph, the solid line indicates BCI _t , the alternate long and short dash line indicates TCI _d , ◯ indicates BCI _t and TCI _d of the sawtooth charge eliminating member, and × indicates BCI of the recording paper charge eliminating member 65.
_t and TCI _d are shown respectively.

As is clear from the graph, in the saw-toothed static eliminator, the drop of TCI _d with the increase of BCI _t is larger than that of the recording paper static eliminator 65 under the environment of high temperature and high humidity, and the transferability is remarkably deteriorated. You can see that

FIG. 14 is a graph showing the results of the life test of the recording paper static eliminator 65 and the saw blade static eliminator. In the graph, ◯ indicates the saw blade static eliminator and × indicates the recording paper static eliminator 65. However,
As an experimental condition, the initial BCI _t was set to about 60 μA.

As shown in the graph, in order to obtain the same BCI _t , it is necessary to apply a voltage of about 2.2 kV to the sawtooth charge eliminating member, while 3.2 kV is applied to the recording paper charge eliminating member 65.
It is necessary to apply a voltage of V. This means that the electric field is more likely to be concentrated in the saw-toothed static eliminator and the static elimination effect is higher in the initial state. It means that the deterioration is quick and the life is shortened. Therefore, the recording paper discharging member 65 can improve the life.

[0053]

The transfer / separation device of the present invention has the following features.
Since the current flowing from the charge wire of the transfer charger is controlled to be constant in order to transfer the toner on the photoconductor onto the recording paper, there is no risk that the transfer state of the toner image will change due to environmental changes, etc. The toner image can be transferred stably. Further, since the recording paper charge eliminating member is not brush-shaped or has a sharp tip, the recording paper charge eliminating member does not have a possibility of being deformed even when an external force is applied to the recording paper charge eliminating member at the time of cleaning or paper jam processing, and a stable charge eliminating effect is obtained. Demonstrate. Furthermore,
Life can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a transfer separation device of the present invention.

FIG. 2 is a partially cutaway perspective view of the transfer separation device of the present invention.

FIG. 3 is an equivalent circuit diagram of the transfer separation device of the present invention.

FIG. 4 is a schematic view showing another embodiment of the transfer separation device.

FIG. 5 is a perspective view showing still another embodiment of the transfer separation device.

FIG. 6 is a perspective view of a main part of the transfer separation device shown in FIG.

FIG. 7 is an enlarged view of a main part of the transfer separation device shown in FIG.

FIG. 8 is an exploded perspective view showing another embodiment of the recording paper separating member.

FIG. 9 is a perspective view showing still another embodiment of the transfer separation device of the present invention.

FIG. 10 is a perspective view of a main part of the transfer separation device shown in FIG.

FIG. 11 is a graph showing a change in charge eliminating current when the material of the recording paper charge eliminating member is changed.

FIG. 12 is a graph showing the relationship between the applied voltage and the static elimination current when the plate thickness of the recording sheet static elimination member made of the material SuS304-CSP is changed.

FIG. 13 is a graph showing the relationship between static elimination current and transfer current and humidity in a high temperature and high humidity environment.

FIG. 14 is a graph showing the results of a life test of a recording paper static eliminator and a sawtooth static eliminator.

FIG. 15 is a sectional view of a conventional transfer separation device.

FIG. 16 is a perspective view of a main part of a conventional transfer separation device.

[Explanation of symbols]

 10, 62, 65 Recording paper static elimination member 20, 61 Transfer charger 21, 61a Shield case 22, 61b Charge wire 28 Transfer transformer 29 Static elimination transformer 30 Photoconductor drum

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takahiro Fukunaga 22-22 Nagaike-cho, Abeno-ku, Osaka City Sharp Corporation (56) References

Claims (3)

(57) [Claims] 1. A transfer / separation device of an image forming apparatus for electrically separating a recording paper from a photosensitive member after transferring a toner image formed on the photosensitive member to a recording paper, the transfer separating device being in a shield case. A transfer charger that transfers the toner image on the photoconductor onto the recording paper by the discharge of the arranged charge wire, and a transfer charger that is arranged on the downstream side in the recording paper conveyance direction.
Conductive thin plate extending in the direction orthogonal to the recording paper conveyance direction
The side edge of the
On the upstream side of the recording paper in the conveying direction,
Multiple recesses to form protruding parts at intervals
And a recording sheet charge-removing member in which parts are arranged in parallel . 2. A toner image formed on a photoconductor is recorded on a recording paper.
After transfer, electrically separate the recording paper from the photoreceptor
A transfer separation device of an image forming apparatus, which discharges a charge wire arranged in a shield case.
To transfer the toner image on the photoconductor onto the recording paper.
And a charger, which is disposed on the downstream side of the transfer charger in the recording sheet conveyance direction,
The side edge portion, which is formed of a conductive thin plate extending in a direction orthogonal to the recording paper conveyance direction, and is close to the recording paper to be conveyed,
The transfer charger is covered with a high resistance material so as to be exposed at appropriate intervals in the longitudinal direction .
An electric current will flow through the recording paper due to the discharge of the di-wire.
Power is supplied to the recording paper discharging member to which a bias voltage is applied and the charge wire of the transfer charger.
Transfer power supply means, and the transfer wire is supplied to the charge wire by the transfer power supply means.
Constant current, excluding the current flowing to the recording paper static elimination member
A transfer / separation device including a control unit. 3. A toner image formed on a photoconductor is recorded on a recording paper.
After transfer, electrically separate the recording paper from the photoreceptor
A transfer separation device of an image forming apparatus, which discharges a charge wire arranged in a shield case.
To transfer the toner image on the photoconductor onto the recording paper.
And a charger, which is disposed on the downstream side of the transfer charger in the recording sheet conveyance direction,
It is composed of a conductive thin plate extending in the direction orthogonal to the recording paper conveyance direction, and protrudes at an appropriate interval in the longitudinal direction on the side surface of the side edge portion near the recording paper to be conveyed, which is upstream in the recording paper conveyance direction. A plurality of concave portions are arranged side by side so that a portion to be formed is formed .
An electric current will flow through the recording paper due to the discharge of the di-wire.
Power is supplied to the recording paper discharging member to which a bias voltage is applied and the charge wire of the transfer charger.
Transfer power supply means and char by the transfer power supply means
The current supplied to the di-wire flows to the recording paper static elimination member.
The transfer component having means for constant current control excluding the current
Separation device.