JPH0844222A - Image forming device - Google Patents

Abstract

PURPOSE:To provide excellent transfer performance and a stable separability regardless of the state of an original by providing a transfer means having a pin-shaped electric field applying member divided in a main scanning direction and selecting/switching the electric field applying member of the transfer means in response to a pixel picture signal. CONSTITUTION:A laser diode 10 is driven with each pixel picture signal from the original 1, to form an electrostatic latent image on a photoreceptor drum. A clock pulse signal generated from a laser signal is transmitted to a multistylus type transfer pin electrode 34 corresponding to each toner image, etc., by the work of a controller 30 and a storage element 31. Each switch of a transfer switching circuit 33 is changed over in accordance with the rotation of the photoreceptor drum 14, with the above operations, so that a transfer bias is applied to the multistylus transfer pin electrode 34 corresponding to a part having toner, to perform a transfer. Then, a transfer paper 18 after receiving a transfer electric field by the switching of on and off of transfer output can be separated from the drum 14 in such a manner that only a surplus charge applied by the transfer is discharged against a destaticization stylus 38.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine or a printer which utilizes a process such as an electrostatic recording system or an electrophotographic system.

[0002]

2. Description of the Related Art As a conventional general image forming apparatus, for example, there is an electrophotographic digital copying machine shown in FIG.

That is, the image of the original 1 to be copied is read by the photoelectric conversion element 2, the obtained analog image signal is amplified to a predetermined level by the amplifier 3, and the analog-digital converter (A / D in the figure). The D converter 4 converts the digital image signal into, for example, an 8-bit digital image signal.

Next, this digital signal is supplied to a .gamma. Converter (a converter which is composed of a 256-byte RAM in this example, and which performs density conversion by a look-up table method) 5, is .gamma.-corrected, and is then subjected to digital-analog conversion. Bowl (D / A in the figure)
Converter 6).

Here, the digital image signal is converted into an analog image signal again and supplied to one input of the comparator 8. The other input of the comparator 8 is supplied with a triangular wave signal of a predetermined cycle generated from the triangular wave generating circuit 7, and the analog image signal supplied to one input of the comparator 8 is compared with this triangular wave signal. Pulse width modulated.

The pulse-width-modulated image signal is directly input to the laser drive circuit 9, and the laser diode 10
The laser light emitted from the laser beam is scanned in the main scanning direction by a well-known polygon mirror 11, passes through the f / Θ lens 12 and the reflection mirror 13, and is irradiated onto the photosensitive drum 14 which is an image carrier rotating in the arrow direction. , Will form an electrostatic latent image.

On the other hand, the photosensitive drum 14 is uniformly neutralized by the pre-exposure device 15 and is uniformly negatively charged by the primary charging device 16. After that, upon receiving the above-mentioned laser light irradiation, an electrostatic latent image corresponding to the image signal is formed. This electrostatic latent image is developed into a visible image by negatively charged toner (not shown) contained in the developing device 17.

On the other hand, a transfer paper 18 serving as a transfer medium that has been fed and conveyed in synchronization with the image forming process of the photosensitive drum 14.
Is superposed on the toner image which is a visible image on the photosensitive drum 14 at the transfer portion T, and at the same time, a positive transfer bias having a polarity opposite to the charging polarity of the toner is applied by the transfer charger 19. As a result, the toner image is attracted onto the transfer paper 18.

Next, the transfer paper 18 is decharged by the separation charger 20 and the transfer paper 18 on which the toner image is transferred is separated from the photosensitive drum 14. After that, the transfer paper 18 is transported in the direction of the arrow by the transport unit 21, and the toner is fixed on the transfer paper 18 by the fixing device 22. The photosensitive drum 14 that has been subjected to the transfer / separation action removes residual toner and the like by the cleaner 21.
Then, it is cleaned and used for the next image formation.

As a transfer means for transferring the toner image of the original document carried on the photosensitive drum 14 onto the transfer paper 18, corona discharge is used from the back surface of the transfer paper 18 opposite to the transfer surface in contact with the photosensitive drum 14. The transfer charger 19 and a bias roller (not shown) uniformly apply a transfer bias having a polarity opposite to that of the toner to be transferred to the entire surface of the transfer paper 18 to attract the toner to the transfer paper 18 at the same time. ,
An electrostatic attraction force acts between the transfer paper 18 and the photosensitive drum 14 due to the transfer bias, and the transfer paper 18 and the photosensitive drum 14 come into close contact with each other.

At the next moment, in order to reduce the electrostatic attraction force and separate the transfer paper 18 from the photosensitive drum 14, an alternating current or a bias electric field in which a direct current is superposed thereon is applied to a separation charger 20 using corona discharge. I used a static elimination needle (not shown).

[0012]

However, in the case of the above-mentioned general prior art, in order to satisfactorily transfer the toner image onto the transfer paper and surely separate the transfer paper from the photoconductor, It is necessary to adjust the strength of action of the transfer charger and the separation charger separately so as to be stable.

That is, in a general image forming apparatus, it is necessary for the transfer paper to have an electric charge in order to transfer the toner image on the photoconductor onto the transfer paper. In order to separate the transfer paper, it is necessary that the transfer paper be sufficiently neutralized, and it is necessary to perform these contradictory actions at extremely close positions.

In order to obtain a good toner transfer onto the transfer paper, the voltage applied to the transfer charger may be increased to increase the application of electric charges to the transfer paper. In other words, the larger the amount of toner on the photosensitive drum to be transferred onto the transfer paper, the larger the optimum transfer charge amount for transferring all of the toner most efficiently.

However, if the charge application to the transfer paper is increased, the charge removal of the transfer paper by the separation charging device becomes insufficient, and there is a risk that the transfer paper is not separated from the photoconductor and is caught while being adsorbed. There is. In other words, in other words, when the transfer charge is applied, the optimum static elimination current that can be separated most stably is also determined.

In order to prevent such separation failure,
If the action of the separation charger is strengthened, the charge removal action of this separation charger will extend to the charging range of the transfer charger.
There is a problem that the transfer operation of the toner image on the transfer paper by the transfer charger becomes insufficient, and the toner image is likely to be missing.

It is necessary to adjust the strengths of the operations of the transfer charger and the separation charger so that they are individually stable, but their stable regions are extremely narrow, and there is a problem that the adjustment work is extremely difficult. is there.

Even if the transfer / separation conditions are optimally set for a certain document state, the optimum transfer / separation conditions will naturally change if the document state changes. In other words, the stable region where the strengths of the operations of the transfer charger and the separation charger are individually stable is changed each time depending on the state of the original.

In general, in the case of characters and line originals that are most frequently used in copying machines and the like, the image portion, that is, the portion with toner and the non-image portion, that is, the portion without toner, are microscopically electrostatic. If the impedance is different and a sufficient toner transfer is attempted, a strong transfer bias is required, and the electrostatic attraction force between the photosensitive drum and the transfer material becomes strong in the non-image area, making it difficult to separate the image area and the non-image area. There is a problem that the sharpness of the image is reduced due to the potential difference between the parts.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and its object is to form an image which always has good transfer performance and stable separation performance regardless of the state of the original. To provide a device.

[0021]

To achieve the above object, in the present invention, a latent image forming means for forming an electrostatic latent image on an image support according to a pixel image signal having image information to be formed. And an image forming apparatus having a developing unit that develops the electrostatic latent image into a visible image, and a transferring unit that transfers the visualized image on the developed image support by applying an electric field to a transfer material. Storage means for storing a pixel image signal having image information to be formed, transfer means having a pin-shaped electric field applying member divided into a plurality in the main scanning direction, depending on a pixel image signal having image information to be formed It is characterized in that it has selection / switching means for selecting and switching the electric field applying member of the transfer means.

In addition, in the image forming apparatus having the above characteristics, a separating means having a plurality of pin-shaped electric field applying members divided in the main scanning direction and a pixel image signal having image information to be formed are provided. It is characterized by having a means for selecting and switching the electric field applying member of the separating means.

[0023]

In the image forming apparatus having the above structure, the original to be copied is read by the photoelectric conversion element, converted into a photoelectric conversion signal corresponding to the density of each pixel decomposed into a large number of pixels, and converted into an analog image signal. Sent to the image signal processing circuit,
Here, each pixel is converted into a pixel image signal having an output level corresponding to the density of the pixel and sent to the pulse width modulation circuit.

The output signal from the pulse width modulation circuit is input to the semiconductor laser for forming a latent image and is supplied to one input of the AND circuit for determining the output of transfer. A clock pulse signal from a clock pulse oscillator is supplied from the other input of the AND circuit, and a clock having a number corresponding to the density of each pixel, that is, the presence / absence of toner and the amount of toner for each pixel is supplied. Outputs a pulse signal,
The data is supplied to the selection / switching means and stored in the storage means.

The selection / switching means extracts a clock pulse signal from the storage means at the timing of transfer or separation, and based on this signal, the electric field applying member divided into a plurality of parts in the main scanning direction. By switching each switch so as to selectively apply the transfer bias from the transfer power source and the separation bias from the separation power source, the transfer bias and the separation bias are selectively applied only to the image portion during transfer of image formation by opening and closing. As a result, by performing transfer with the minimum required output, good transfer performance and stable separation performance are always obtained regardless of the state of the original.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to illustrated embodiments. FIG. 1 illustrates an image forming apparatus according to an exemplary embodiment of the present invention.
3 to FIG. 3, FIG. 1 shows the entire configuration of the present embodiment, FIG. 2 shows an example of signal conversion in each section, and FIG.
The XY cross section in is shown. An image of the original 1 to be copied in FIG. 1 is projected onto a photoelectric conversion element 2 such as a charge imaging element by an image projection lens 24. The photoelectric conversion element 2 decomposes the image of the document 1 into a large number of pixels, converts the image into a pixel image signal having an output level corresponding to each pixel density, and sends the pixel image signal to the pulse width modulation circuit 25. The pulse width modulation circuit 25 forms and outputs a laser drive pulse having a width corresponding to the level of each input pixel image signal. That is, as shown in FIG. 2A, a wider drive pulse W is provided for a high density pixel image signal, and a narrower drive pulse S is provided for a low density pixel image signal. , A drive pulse I having an intermediate width is formed for the medium-density pixel image signal.

The laser drive pulse output from the pulse width modulation circuit 25 is supplied to the laser diode 10 to cause the laser diode 10 to emit light for a time corresponding to the pulse width. Therefore, the laser diode 10 is driven for a longer time for a high density pixel and is driven for a shorter time for a low density pixel. Therefore, the photosensitive drum 14 is exposed by the optical system to a long range in the main scanning direction for high density pixels and a short range in the main scanning direction for low density pixels. That is, the dot size of the electrostatic latent image differs with the density of the pixel. Therefore, the toner development amount for high density pixels is larger than the toner development amount for low density pixels. Figure 2 (d)
The low, medium, and high density electrostatic latent images are indicated by L, M, and H, respectively.

The laser light 10a emitted from the laser diode 10 is swept by the rotating polyhedron 14, and f / Θ
A spot latent image is formed on the photosensitive drum 14 by a lens 15 such as a lens and a reflection mirror 16 that directs the laser light 10a toward the photosensitive drum 14 which is an image carrier. Thus, the laser beam 10a scans the photosensitive drum 14 in a direction substantially parallel to the rotation axis of the photosensitive drum 14, that is, in the main scanning direction to form an electrostatic latent image.

The photosensitive drum 14 is amorphous silicon,
It is an electrophotographic photosensitive drum that has selenium, an organic semiconductor, etc. on its surface and rotates in the direction of the arrow. It is uniformly charged by the primary charger 16 after being uniformly discharged by the pre-exposure device 15. After that, the laser light modulated corresponding to the above-mentioned image information signal is exposed and scanned, whereby an electrostatic latent image corresponding to the image information signal is formed. This electrostatic latent image is reversely developed by the developing device 17 containing toner to form a visible image, that is, a toner image.

On the other hand, the transfer paper 18 serving as a transfer medium that has been fed and conveyed in synchronization with the image forming process of the photosensitive drum 14.
Is superposed on the visible toner image on the photosensitive drum 14 at the transfer portion T, and at the same time, a positive transfer bias having a polarity opposite to the charging polarity of the toner is applied to the multi-needle transfer pin electrode 34. And the toner image is attracted to the transfer paper 18.

Next, the transfer paper 18 is discharged from the photosensitive drum 14 by removing the charge from the transfer paper 18 by the charge removing needle 38 connected to ground or a self-impedance element such as a varistor or a resistor. It After that, the transfer paper 18 is conveyed in the direction of the arrow by the conveying device 27, and the toner is fixed on the transfer paper 18 by the fixing device 23. Further, the photosensitive drum 14 that has been subjected to the transfer / separation action removes residual toner and the like from the cleaner 2
It is cleaned in 1 and is used for the next image formation.

On the other hand, the output signal from the pulse width modulation circuit 25 is input to the laser diode 10 to be used for forming an electrostatic latent image, and at the same time one of the AND circuits 64 is used to determine the output of transfer. Is supplied to the input of. A clock pulse as shown in FIG. 2B is supplied from the clock pulse oscillator 29 to the other input of the AND circuit 28.

Therefore, from the AND circuit 28, as shown in FIG. 2C, the number of clock pulses corresponding to the pulse width of each of the laser driving pulses S, I, and W, that is, the density of each pixel is corresponded. Several clock pulses are output. Therefore, this clock pulse signal has information on the presence / absence of toner and the amount of toner for each pixel.

Therefore, this clock pulse signal is sent to the CPU.
And the like, and stores it in a storage element 31 such as a RAM. The control device 30 takes out a clock pulse signal from the memory element 31 at the timing of transfer, and based on this signal, with respect to the multi-needle type transfer pin electrode 34 which is a transfer bias applying member corresponding to the pixel in which the laser diode is turned on. Then, the switches of the transfer switching circuit 33 are switched to open and close so that the transfer bias is selectively applied from the transfer power source 32.

For example, referring to FIG. 3 which is a sectional view taken along the line XY of FIG. 1, the laser diode 10 is driven by each pixel image signal from the original 1 to form an electrostatic latent image on the photosensitive drum and a toner image. , 40a, 40b, 40c, the clock pulse signal generated from the laser drive signal is generated by the controller 30 and the memory element 31 as described above.
Each pin electrode 34 of the multi-needle transfer pin electrode 34 corresponding to
Each switch 33a, 3 of the transfer switching circuit 33 so that the transfer bias is supplied to each of a, 34b, 34c.
Close 3b and 33c. Such an operation is performed by switching the switches of the transfer switching circuit 33 in accordance with the rotation of the photosensitive drum 14 which rotates in the direction of the arrow in the drawing, and the multi-needle type transfer pin electrode 34 corresponding to the part where the toner is present. Transfer is performed by applying a transfer bias.

Next, the transfer paper 18 receives the transfer electric field by switching the transfer output on and off in accordance with the pixel image information.
Is discharged from the photosensitive drum 14 by discharging only the excess charge given by the transfer to the static elimination needle 38 connected to the ground or the self-impedance element.

In this embodiment, as a transfer pin electrode, a phosphor bronze slope having a thickness of 200 μm is pointed toward the photosensitive drum 14 as shown in FIG. 3, and the distance between the tip portions of the pin electrodes is set to 3 mm. Is fixed to a multi-needle electrode fixing member 39 made of an insulating material such as ABS resin.

The tip of each pin electrode of the multi-needle type transfer pin electrode 34 and the photosensitive drum 14 are opposed to each other while maintaining an interval of 1 to 10 mm, more preferably 1.5 to 3 mm, and the transfer bias is a constant current. Controlled and applied. As the electrodes which are the divided voltage applying members, the pin electrodes are preferable because the electric field applying region can be finely divided and the discharge voltage is low.

Here, since the size of one pixel is 400 dpi, it is 63.5 μm, while the distance between the pin electrodes of the multi-needle type transfer pin electrode 34 is 3 mm, and about 50 pixels have one pin electrode. Therefore, the control device 30 treats 50 clock pulses from the storage element 31 as one unit, and if the laser is turned on even in one pixel among the 50 pixels, the transfer bias application corresponding thereto is applied. Transfer switching circuit 3 so that transfer bias is applied to the member
Switch each switch of 3.

In the image forming apparatus having the above-mentioned structure, the transfer can be performed with the minimum required transfer output by selectively applying the transfer bias only to the image portion at the time of transfer. It is possible to obtain excellent transfer performance. Further, the discharge current due to the transfer is small, and the generation of ozone can be reduced. Further, since the transfer bias is not applied to the non-image portion, the transfer paper 18 and the photosensitive drum 14 are
Since it does not adsorb more than necessary, separation is also very easy. Furthermore, since no bias is applied to the space between sheets in the non-image forming area, that is, the area where the transfer material does not exist when using small size paper, damage to the photosensitive drum 14 is reduced and the life of the photosensitive drum 14 is also reduced. Extend. Further, as in the present embodiment, the cost can be reduced by sharing the charge eliminating needle with the multi-needle electrode used for transfer.

Another embodiment of the present invention is shown in FIGS. In the above-described embodiment, the curvature separation method using the charge elimination needle in the separation process is used, but in this embodiment, the pin electrode, which is the transfer bias applying member divided into a plurality in the main scanning direction, is also used in the separation charger. This is an example of the applied electrostatic separation method. Therefore, in the processes other than the separation process, the same parts are given the same reference numerals and omitted.

The clock pulse signal having the information for each pixel, which is issued from the AND circuit 28, is supplied to the control device 30 and stored in the storage element 31. Control device 3
0 is the storage element 3 in accordance with the timing of transfer or separation.
The clock pulse signal is taken out from No. 1 and the transfer bias is separated from the transfer power source 32 to each electrode of the multi-needle type transfer pin electrode 34 and each electrode of the multi-needle type separation pin electrode 37 based on this signal. The switches of the transfer switching circuit 33 and the switches of the separation switching circuit 36 are switched so as to selectively apply the separation bias from the power supply 35 to open and close.

For example, referring to FIG. 5 which is a sectional view taken along the line M--N of FIG. 4, the control device 30 is operated at the timing of the next separation process for the transfer paper 18 which has been subjected to the transfer action as the photosensitive drum 14 rotates. Captures the same data as that at the time of transfer from the memory element 31 and separates it into each pin electrode 37a, 37b, 37c of the multi-needle type separation pin electrode 37 corresponding to 40a, 40b, 40c to which a transfer bias is applied as at the time of transfer. The switches 36a, 36b, 36c of the separation switching circuit 36 are closed so that the bias is applied. Then, with the rotation of the photosensitive drum 14, the control device 30 sequentially switches the switches of the separation switching circuit 36 to separate them. Thus, the separation bias is applied only to the portion to which the transfer bias is applied.

In this embodiment, a phosphor bronze slop having a thickness of 200 μm is formed as the separation pin electrode so that the photosensitive drum 14 is sharpened as shown in FIG. 3 and the distance between the tip portions of the pin electrodes is 3 mm. The electrodes are fixed to a multi-needle electrode fixing member 39 made of an insulating material such as ABS resin. The multi-needle separation electrode 37 used was the same as the multi-needle transfer electrode 36. The tip of each pin electrode of the multi-needle separation electrode 37 and the photosensitive drum 14
Are opposed to each other while maintaining an interval of 1 to 10 mm, more preferably 1.5 to 3 mm, and the separation bias is applied by being controlled by a constant current.

Further, in the above, the bias application of the transfer and separation means is performed by the multi-needle transfer electrode 3 which is a voltage applying member.
6. Multi-needle separation electrode 37 and photosensitive drum 14 or transfer paper 1
Although the direct discharge between 8 was used, the multi-needle type transfer electrode 3
6. Multi-needle separation electrode 37 and photosensitive drum 14 or transfer paper 1
8, an electric field control means such as a mesh grid is arranged to cause an electric discharge between the mesh grid and the multi-needle type transfer electrode 36 and the multi-needle type separation electrode 37, and the discharge current is applied to the photosensitive drum 14 or It is preferable to apply a bias to the mesh grid so as to transfer or separate it so as to supply it to the transfer paper 18 because the discharge current can be further narrowed down and the current amount can be made uniform.

Since the size of one pixel is 400 dpi, it is 63.5 μm. On the other hand, the multi-needle type transfer electrode 3
6. The distance between the multi-needle separation electrodes 37 is 3 mm,
Since the pixel corresponds to one pin electrode, the control device 30
Fifty clock pulses from the memory element 31 are treated as one unit, and the multi-needle type transfer pin electrode 34 is switched.

In the image forming apparatus having the above-described structure, the transfer is performed with the minimum necessary transfer / separation output by selectively transferring only the image portion and transferring the separation bias during the transfer of the image formation. Regardless of the state of the original, good transfer performance and stable separation performance can always be obtained.
Further, since the bias is not applied to the space between the non-image forming areas, the damage to the photosensitive drum 14 is reduced, and the life of the photosensitive drum 14 is extended. Further, the cost can be reduced by sharing the multi-needle electrode used for transfer and separation as in this embodiment.

In the above-mentioned two types of embodiments, the multi-needle type was used as the discharge electrode in the transfer / separation, but the present invention is not limited to this structure and any discharge area can be divided in the longitudinal direction of the photosensitive drum. Good. Further, the bias applying method based on the image pixel information is not limited to the above-mentioned two types of embodiments.

[0049]

The present invention has the above-described structure and operation. By selectively applying the transfer bias and the separation bias only to the image portion during the transfer of the image formation, the minimum necessary transfer / separation output is obtained. Since the transfer can be performed with, the so-called image skipping is reduced and the sharpness of lines and characters is improved, so that good transfer can always be performed regardless of the state of the original.

Further, the discharge current due to transfer / separation can be small, and the generation of ozone can be reduced.

Further, since the bias is not applied to the non-image portion, the transfer paper and the photosensitive drum are not attracted more than necessary, so that stable separation is always performed.

Further, since the bias is not applied to the space between sheets in the non-image forming area, the photosensitive drum is less damaged and the life of the photosensitive drum is extended.

Further, there is an advantage that the cost can be reduced by sharing the multi-needle electrodes used for transfer and separation as in this embodiment.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall schematic configuration according to an embodiment of the present invention.

FIG. 2 is a waveform diagram showing a method of counting density information of an image information signal in the apparatus of the embodiment.

3 is a block diagram showing a schematic configuration of a transfer unit in a cross-sectional view taken along line XY in FIG.

FIG. 4 is a block diagram showing an overall schematic configuration according to another embodiment of the present invention.

5 is a block diagram showing a schematic configuration of a separation unit in a cross-sectional view taken along line MN in FIG.

FIG. 6 is an overall block configuration diagram according to a general prior art.

[Explanation of symbols]

 1 Manuscript 2 Photoelectric conversion element 3 Amplifier 4 Analog-digital converter 5 γ converter 6 Digital-analog converter 7 Triangular wave generator 8 Comparator 9 Laser drive circuit 10 Laser diode 10a Laser light 11 Polygon mirror 12 f / Θ lens 13 Reflection Mirror 14 Photosensitive drum 15 Pre-exposure device 16 Primary charger 17 Developer 18 Transfer paper 19 Transfer charger 20 Separation charger 21 Cleaner 22 Conveyor 23 Fixer 24 Image projection lens 25 Image signal processing circuit 26 Pulse width modulation circuit 27 See Image signal generating circuit 28 AND circuit 29 Clock pulse oscillator 30 Control device 31 Storage element 32 Transfer power source 33 Transfer switching circuit 33a to 33c Each switch of transfer switching circuit 34 Multi-needle transfer pin electrode 34a to 34c Multi-needle transfer pin electrode Each pin electrodes 39 insulating member 40 the toner images portions of the switches 37 the multi-needle type transfer pin electrode 37a~37c multi-needle separation pin electrodes of each pin electrode 35 separated power 36 separate switching circuit 36a~36c separation switching circuit

Claims (4)

[Claims] 1. A latent image forming means for forming an electrostatic latent image on an image support according to a pixel image signal having image information to be formed, and a developing means for developing the electrostatic latent image to form a visible image. An image forming apparatus having a transfer means for transferring the developed visualized image on the image support to a transfer material by applying an electric field, and a storage means for storing a pixel image signal having image information to be formed, A transfer unit having an electric field applying member divided into a plurality in the main scanning direction, and a selection / switching unit for selecting and switching the electric field applying member of the transfer unit according to a pixel image signal having image information to be formed. A characteristic image forming apparatus. 2. The image forming apparatus according to claim 1, wherein the divided electric field applying member of the transfer unit has a pin shape. 3. Separation means having a plurality of electric field applying members divided in the main scanning direction and selection / switching of the electric field applying members of the separating means according to a pixel image signal having image information to be formed. The image forming apparatus according to claim 1, further comprising means. 4. The electric field applying member obtained by dividing the transfer means and the separating means has a pin shape.
The image forming apparatus according to item 1.