JP2000267538A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device equipped with a cleaning device capable of preventing the turnover and the damage of a cleaning blade. SOLUTION: This device is provided with the cleaning blade 81 press- contacting with a photoreceptor drum 1 and a magnetic roller 83 arranged on this side of the blade 81 and arranged proximately to the drum 1. In such a case, the toner accumulated near the roller 83 is partially transferred to the drum 1 and moved toward a press-contact part N between the blade 81 and the drum 1 in a period when the roller 83 is not rotated in the midst of the rotation of the drum 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for cost reduction in such an image forming apparatus.
Regarding the driving of each element constituting the image forming apparatus, or the rotation member constituting each element, as shown in FIG. Each of the developing roller 41, the heating roller 71 and the pressure roller 72 constituting the fixing unit 7, the rotating member of the cleaning device 8 for cleaning the surface of the photosensitive drum 1, and the transporting device 9 for transporting the transfer material are each provided with a dedicated motor. M1
As shown in FIG. 10, the driving system driven by the motor M1 and the driving system driven by the motor M2 are distinguished from each other, and the photosensitive drum 1 is driven by the motor M1. And other rotating members (developing roller 4) by motor M2.
1. Rollers 71 and 72 of fixing means 7, transfer material conveying device 9
, Etc.) have been proposed.

[0003] Of course, as shown in FIG. 11, a rotating member constituting all the elements of the image forming apparatus is a single motor M.
Although it is ideal to drive at 1, the driving torque becomes large, which may cause a rise in the temperature of the motor or damage to the transmission gear. Hard to say.

On the other hand, in a known image forming apparatus in which a process of transferring a toner image formed on the surface of a photosensitive drum as a latent image carrier to a transfer material such as paper is repeated, toner remaining on the surface of the photosensitive drum after transfer is transferred. , Paper powder, rosin, deposits such as talc and the like (residual toner and the like t2; the same applies hereinafter).
Is removed by the cleaning means.

FIG. 6 shows a cleaning means of this type in which a blade 81 made of an elastic material such as rubber is pressed against the surface of the photosensitive drum 1.

However, the use of the blade 81 alone is not always effective for removing residual toner and the like on the surface of the photosensitive drum 1. Particularly, in a high-speed image forming apparatus, such removal performance tends to be insufficient.

In order to make up for the disadvantage of the blade, there has been proposed a cleaning means in which a roller made of an elastic material such as silicon rubber is rubbed against the surface of the photosensitive drum by pressing to remove residual toner and the like.

However, in the cleaning means using such an elastic roller, residual toner or the like adhering to the elastic roller is scattered, and the collected toner is again rubbed against the photosensitive drum by rubbing against the photosensitive drum. There was a risk of inviting.

Therefore, in order to eliminate such a drawback, as shown in FIG. 8, a magnetic roller 83 mainly composed of a permanent magnet is used.
The cleaning means has been proposed in which the magnetic roller 83 is disposed close to the surface of the photosensitive drum 1 to remove the residual toner t2 as described above.

In the above-described conventional example, the cleaning is performed by pressing the elastic roller itself against the photosensitive drum and rubbing it. On the other hand, the cleaning device 8 using the magnetic roller 83 shown in FIG. A gap G1 exists between the photosensitive drum 1 and the photosensitive drum 1.

In the gap G1, as shown in FIG. 8, the collected toner t3 existing between the magnetic roller 83 and the photosensitive drum 1 is in a state where the spikes are raised so as to be along the lines of magnetic force of the magnetic roller 83. The recovered toner t3 in the standing state
As a result, the surface of the photosensitive drum 1 is cleaned, whereby the cleaning property is further improved, and uneven sliding is less likely to occur.

The magnetic roller 83 is disposed in the cleaning means 8, and a scraping means 84 is disposed in contact with the magnetic roller 83.

[0013] The surface of the magnetic roller 83 is used for collecting collected toner and the like t3.
A portion S where the collected toner t3 accumulates is formed between the photosensitive drum 1 and the photosensitive drum 1, and thereby the surface of the photosensitive drum 1 is rubbed, and the residual toner and the like t2 on the surface of the photosensitive drum 1 are sucked and removed.

In the cleaning means having such a magnetic roller 83, when the magnetic roller 83 is rotated so as to be in the same direction as the rotation direction A of the photosensitive drum 1, the circumference of each of the photosensitive drum 1 and the magnetic roller 83 is changed. Since the respective peripheral surfaces move in opposite directions on the adjacent surfaces facing each other, the relative speed between the photosensitive drum 1 and the peripheral surface of the magnetic roller 83 increases,
The cleaning effect can be increased without rotating the magnetic roller 83 at high speed. This is a consideration for the motor M2 that rotationally drives the magnetic roller 83. The rotation in the reverse direction may be performed at an appropriate relative speed.

Further, the cleaning ability is improved as the gap is smaller.

[0016]

In an image forming apparatus provided with such a cleaning device, there is a state where the photosensitive drum as a latent image holding means is rotating, but the magnetic roller of the cleaning device is not rotating. .

This is not only when the driving means for rotating the photosensitive drum as the latent image holding means and the driving means for rotating the magnetic roller of the cleaning device are different, but also as shown in FIG. The driving means for rotating the photosensitive drum 1 and the driving means for rotating the magnetic roller of the cleaning device 8 are the same driving means M1, and the driving means M1 is driven by the driving force contact / separation means C such as a clutch. The same applies to the case where force is transmitted to a magnetic roller.

In any case, in such a state,
For some reason, for example, when the amount of toner contained in the developing unit 4 is insufficient, or when a large amount of images having extremely low image density are output, the blade 81 of the cleaning device 8 is pressed against the photosensitive drum 1 as shown in FIG. In some cases, the toner serving as the lubricant does not exist in the portion N, and eventually, the blade 81 may be turned or damaged.

Further, even when the blade is not turned up or broken, the surface of the photosensitive drum 1 serving as a latent image holding means may be damaged and appear as an image defect.

Further, in a state where the photosensitive drum 1 is rotating but the magnetic roller 83 is not rotating, as shown in FIG. 8, the blade 81 is constantly pressed against the photosensitive drum 1 by a lever 87 which is biased by a spring. It is conceivable to temporarily separate the blade 81 from the photosensitive drum 1 by rotating the lever 87 clockwise in FIG. 8 against the urging force of the spring by the actuator shown, but the mechanism becomes complicated. Also, every time the blade 81 is separated, the pressure contact force and pressure contact angle θ of the blade 81 may change, which is not preferable.

In this state, it is conceivable to transfer the new toner from the developing means to the photosensitive drum 1 and supply the new toner to the pressure contact portion N between the blade 81 and the photosensitive drum 1 (a so-called "black band"). This leads to waste of new toner to be used for visualization, which is also undesirable.

An object of the invention according to the present application is to prevent a plate-shaped member mainly composed of an elastic material, which serves as a cleaning means for a latent image carrying means, from being turned up and damaged, and to maintain the cleaning performance of the latent image carrying means for a long time. It is an object of the present invention to provide a simple and inexpensive image forming apparatus having a possible configuration.

[0023]

According to a first aspect of the invention, a latent image carrier on which a latent image is formed and a latent image formed on the latent image carrier are developed. Developing means, and cleaning means for removing toner on the latent image carrier remaining after the transfer, the cleaning means comprising: a first plate-shaped member which is in pressure contact with the latent image carrier; A rotatable magnetic field generating means disposed in the latent image carrier with a gap G1 upstream of the plate member with respect to the rotation direction of the carrier;
In the image forming apparatus having the magnetic field generating means and a second plate-shaped member provided with a gap G2, the cleaning means may be configured such that the latent image carrier is rotating, and the magnetic field generating means is During a period in which the toner is not rotating, a part of the toner in the vicinity of the magnetic field generating means is transferred to the latent image carrier and moved toward a pressure contact portion with the plate member.

According to a second configuration for realizing the object of the invention according to the present application, in the first configuration, the cleaning unit controls the transfer of the toner from the vicinity of the magnetic field generation unit to the latent image carrier. This is performed by changing the potential of the latent image carrier.

According to a third configuration for realizing the object of the invention according to the present application, in the above-mentioned first configuration, the cleaning unit controls the transfer of the toner from the vicinity of the magnetic field generation unit to the latent image carrier. This is performed by changing the potential of the magnetic field generating means.

A fourth structure for realizing the object of the present invention according to the present invention is any one of the above structures, wherein the driving means for the magnetic field generating means in the cleaning means and the driving means for the latent image holding means are different. Things.

According to a fifth configuration for realizing the object of the invention according to the present application, in any one of the above configurations, the gaps G1 and G2 satisfy the following expression.

250 (μm) ≦ G1-G2 ≦ 500 (μm)

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIGS. 1 and 3 show a first embodiment of the present invention.

FIG. 3 shows a schematic configuration of a multifunction printer (hereinafter abbreviated as MFP), which is an electrophotographic image forming apparatus according to the first embodiment.

The photosensitive drum 1 as a latent image carrier has an arrow A
, A cleaning device 8, a pre-exposure lamp 9 as a pre-exposure device, a primary charger 2 as a primary charging device, an exposure device 3, a developing device 4 as a developing device, and a transfer device. Transfer / separation device 5 as separation means,
A fixing device 7 as a fixing unit for fixing the toner image transferred onto the transfer material m such as paper to the transfer material m, and the transfer material m is sent from the paper feeding unit to the transfer position of the photosensitive drum 1. , A conveying device 11 for conveying the image to the fixing device 7, and other image forming members.

As shown in FIG. 1, the cleaning device 8 includes a photosensitive drum 1 in a rotation direction A of the photosensitive drum 1 inside the container.
The blade 81 is disposed in contact with the
A magnetic roller 83 is arranged close to the surface of the photosensitive drum 1 with a gap G1 therebetween, and rotates at an appropriate relative speed to the peripheral surface of the photosensitive drum 1 in a non-contact manner.

Around the magnetic roller 83, a scraping plate 84 as a regulating means is provided in the container of the cleaning device 8 as a gap G.
2, scraping off a part of the toner or other foreign matter removed by the blade 81 or the magnetic roller 83 and dropping it downward in the container of the cleaning device 8,
Next, a screw-shaped screw shaft 85 as a conveying means is used.
Discharges in the direction of the toner storage means (not shown). The scraping plate 84 as a regulating means includes:
It has been found that a magnetic material such as SPCC is desirable, and the relationship between the gap G1 and the gap G2 is desirably satisfied by the following equation between the gap G1 and the gap G2.

250 μm ≦ G 1 −G 2 ≦ 500 μm The magnetic roller 83 is preferably made of a material having elasticity such as silicon rubber or urethane rubber. In order to impart magnetism, magnetic powder is mixed into the roller 83. Alternatively, another rubber magnet may be used.

As shown in FIG. 4, the magnetic roller 83 has a continuous groove 8 on the outer periphery, the position of which is different in the axial direction in the circumferential direction.
3a may be applied. Various arrangements of the groove 83a can be adopted, for example, single or multiple spirals, spirals in forward and reverse directions, and various mesh patterns can be adopted.

The photosensitive drum 1 according to the present embodiment has an a-Si (amorph) containing at least amorphous silicon and hydrogen atoms.
(house-Silicon) type photoreceptor.

The image forming step will be described.

After the surface of the photosensitive drum 1 is uniformly charged (having a potential of about 500 V at this time) by a primary charger 2 arranged around the photosensitive drum 1, the photosensitive drum 1 is exposed to light by exposure means 3 such as a semiconductor laser. An electrostatic latent image is formed on the drum 1 and the toner image visualized by the developing device 4 is transferred to the transfer material m by the transfer separation device 5 at the transfer site TZ.

The transfer material m is transferred to the fixing device 7 and the transfer device 11
The residual toner and the like remaining on the surface of the photosensitive drum 1 without contributing to the transfer at the transfer portion reach the cleaning device 8 and are removed from the surface, and the residual charge is removed by the pre-exposure lamp 9. The surface of the photosensitive drum 1 is ready for the next image forming step, and reaches the primary charging portion PCZ again.

In the present embodiment, the blade 81 has a hardness of 80 degrees (JIS A), a length of 330 mm, and a width of 2 mm.
A material mainly composed of urethane rubber having a thickness of 0 mm and a thickness of 3 mm is used.
It is.

The blade 81 is driven by a pressure driving mechanism 87 composed of a pressure spring and a rotating lever 87 as shown in FIG.
As shown in the figure, the photosensitive drum 1 is pressed against the photosensitive drum 1 at a linear pressure of 0.13 N / cm while reciprocating at a frequency of 1 Hz in a direction X parallel to the rotation axis of the photosensitive drum 1.

As the magnetic roller 83, a magnetic roller in which a magnetic material was dispersed in silicon rubber was used.

The rotation of the magnetic roller 83 is made to rotate in the same direction as the rotation direction A of the photosensitive drum 1 or in the opposite direction. The relative speed with respect to the speed was set from 0% to 500%, and the gap (G1) between the magnetic roller 83 and the photosensitive drum 1 was set to 1 mm.

Further, a bias power supply 89 is connected to the magnetic roller 83. When the magnetic roller 83 is stopped and the photosensitive drum 1 is rotated for a predetermined time or more, the potential of the photosensitive drum 1 is lower than the surface potential of the photosensitive drum. The bias voltage Vrm is applied so that the potential increases by about 50 to 200 V, that is, so that the toner in the stagnant portion S (shown in FIG. 8) transfers to the photosensitive drum 1. In this transfer, the toner is transferred at a speed of 20 to 100 mg / sec in a standard setting. The bias voltage Vrm may be DC, but may be AC.

Further, the bias voltage Vrm and the application time thereof may be controlled based on the driving torque of the magnetic roller 83, the ambient temperature and humidity, the number of accumulated output pages of the photosensitive member, and the like.

The toner to be used is an insulating toner having at least a binder resin, and the binder resin is, for example, styrene such as polystyrene, poly-P-chlorostyrene, polyvinyltoluene or the like, or a substitute thereof. Polymer, styrene-P-chlorostyrene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-acrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene -Acrylonitrile copolymer, styrene-
Vinyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-
Styrene copolymer such as indene copolymer, polyvinyl chloride, phenolic resin, natural resin modified maleic acid resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester resin, polyurethane, polyamide resin, furan resin, polyvinyl Butyral, epoxy resin, xylene resin, polyvinyl butyral, terpene resin, coumarone indane resin, petroleum resin and the like can be used.

The toner used in the present invention is formed by mixing a colorant into the above-mentioned binder resin. As a coloring agent,
Magnetic powder, pigments, dyes and the like can be used. As magnetic powder,
For example, metals such as iron, nickel, copper, manganese, chromium, rare earth and the like, and their alloys, or oxides and ferrites which are not oxidized or surface oxidized can be used. As the pigment, carbon black or the like can be used.

Further, in addition to these components, a toner formed by adding a lubricant such as silicon oxide, strontium titanate, and cerium oxide to improve the fluidity of the toner is used.

Further, as a charge control agent, for example, there are generally quaternary ammonium compounds and organic dyes, particularly, basic dyes and salts thereof. By adding a nigrosine base and nigrosine, stirring and thinning in the developing device 4 can be performed. A positive charge of 5 to 10 μC / g is given by an operation such as layering, and adheres to a portion of the photosensitive drum 1 where the potential is low.

The collected toner t3 and the like (see FIG. 8) adhere to the magnetic roller 83, and the photosensitive drum 1 is rubbed and polished with silicon oxide, oxidized / unoxidized iron and the like in the collected toner. This component varies depending on the degree of contribution of rubbing and polishing of the recovered toner and the like. In addition, there is a difference in the fluidity and shape between the recovered toner and the like that have deteriorated due to the rubbing and the undegraded recovered toner and the like.

The collected toner and the like are in a state of ears along the lines of magnetic force H formed by the grooves 83 a formed in the magnetic roller 83, and have the same shape as the cross section of the groove 83 a of the magnetic roller 83, and are in contact with the photosensitive drum 1. There is a space between them.

Therefore, with the rotation of the magnetic roller 83, the collected toner and the like accumulated in the stagnant portion S (see FIG. 8) move in the axial direction by the rotation of the magnetic roller 83, and clean the surface of the photosensitive drum 1. The ability does not change locally.

Example 1 Next, in the MFP according to the present embodiment, in a severe environment of a temperature of 30 ° C. and a relative humidity of 80%, a continuous output of 1,000,000 pages of JIS 4-size transfer material was performed, and then the image density was increased. The uniformity, the presence or absence of poor cleaning, and the presence or absence of image deletion were evaluated. Table 1 shows the evaluation results of Example 1.

[0054]

[Table 1]

If a cleaning failure occurs, the toner remaining on the surface of the photosensitive drum is developed into a non-colored portion and appears as black streaks.

The evaluation methods for each evaluation in Table 1 and the meanings of the symbols in Table 1 are shown below.

Evaluation Items: Image Density Uniformity The image density difference between the front side and the back side of the output image was visually observed and measured using an image reflection densitometer RD914 (manufactured by Macbeth).

A: The image density difference is less than 0.02, and the image density difference cannot be visually recognized.

…: The image density difference is 0.02 or more and less than 0.05, and almost no image density difference can be visually recognized.

Δ: The image density difference is 0.05 or more and less than 0.15, and the image density difference can be visually recognized.

Δ: The image density difference is 0.15 or more, and the image density difference can be clearly recognized by visual observation.

Evaluation item: Cleaning performance The presence or absence of cleaning failure was evaluated based on whether or not streaks in the rotation direction of the photosensitive drum 1 appeared on a solid white image. If streaks were visually observed, it was judged that cleaning was defective.

A: No cleaning failure.

…: The stripe in the rotation direction of the photosensitive drum 1 is 3 m wide
m and within two.

△: Streaks in the rotation direction of photosensitive drum 1 are 3 m wide
2 or more within 3 m and 1 or less within 3 mm.

…: Streaks in the rotation direction of photosensitive drum 1 are 3 m wide
m or more, and 2 or more, 3 mm or more.

Evaluation item: presence / absence of image deletion It was determined whether or not fine line images arranged at an interval of f1 (lines / mm) could be determined without collapsing.

A: It is possible to determine a thin line of f1 = 9 without collapsing, and there is no blur.

.Largecircle .: A thin line of f1 = 8 can be determined without being collapsed, and there is no blur.

△... Up to the thin line of f1 = 7 can be determined without being collapsed, and there is a slight blur.

... Fine lines of f1 = 7 cannot be discriminated, and there are many blurs.

Evaluation item: blade state The surface of the contact portion on the surface of the photosensitive drum 1 was observed with a microscope, and the presence or absence of a burr-like portion and an image were judged.

A: No burrs like before continuous copying.

△: Although there is a burr-like portion, it is minute and does not lead to poor cleaning.

▲: There is a burr-like portion, and poor cleaning appears on the image.

Evaluation Items: Fusing After continuous copying, the side of the blade 81 in contact with the surface of the photosensitive drum 1 and the surface of the photosensitive drum 1 were observed, and the evaluation was made based on the blade state and the image.

◎: No fusion.

△: There is some fusion, but it is minute and does not lead to poor cleaning.

▲: Poor cleaning appears on the image due to fusion.

According to Table 1, it is understood that a simple and inexpensive image forming apparatus having a configuration capable of preventing the blade from being turned up and damaged and maintaining the cleaning performance for a long period of time is provided.

Second Embodiment In the second embodiment, when the photosensitive drum 1 is rotated for a predetermined time or more while the magnetic roller 83 is stopped, the magnetic roller 83 At the same time that the bias voltage Vrm is applied so that the potential at 83 is higher than the surface potential of the photosensitive drum 1 by about 50 to 500 V, that is, so that the toner in the stagnant portion S transfers to the pressure contact portion N, The exposure amount Ipe of the pre-exposure lamp 9 is increased to make the surface potential of the photosensitive drum 1 substantially zero.
It is the same as the first embodiment except that no current flows through the primary charger 2.

That is, the exposure amount Ipe during the normal period
Is 4 lux · sec, but 10 lux · sec.

When the pre-exposure means 9 is an LED or the like, this is performed by increasing the voltage applied to the LED or the like.

Example 2 An image was output to the second embodiment under the same conditions as in the first embodiment, and the results of Example 2 in which each evaluation was performed are shown in Table 1 above.

According to the present embodiment, it is also possible to provide a simple and inexpensive image forming apparatus having a structure capable of preventing the blade from being turned up or damaged and maintaining the cleaning performance for a long time.

Third Embodiment FIG. 2 shows a third embodiment.

In the present embodiment, as shown in FIG. 2, the magnetic roller 83 has a sleeve-shaped circular tube 83c made of A6063 whose surface is roughened with fine particles made of glass or the like, and is fixedly installed therein. The configuration is the same as that of the first embodiment except that it is configured by an electromagnet 83b.

Then, the sleeve-shaped circular tube 83c rotates clockwise at a peripheral speed of the photosensitive drum of 80%.

In this embodiment, in order to transfer the toner in the staying portion S to the pressure contact portion N, the power supply to the electromagnet 91b is stopped.

Since the electromagnet 83b loses magnetism, the staying portion S
This is because the suction force to the toner does not work.

By covering the electromagnet 83b with the sleeve-shaped circular tube 83c, the accuracy of the gap G1 is improved, and the power supply 8
However, the cost of the image forming apparatus is slightly increased.

Example 3 An image was output to the second embodiment under the same conditions as in the first embodiment, and the results of Example 3 in which each evaluation was performed are shown in Table 1 above.

According to this embodiment, it is also possible to provide a simple and inexpensive image forming apparatus having a structure capable of preventing the blade from being turned up or damaged and maintaining the cleaning performance for a long period of time.

Although three embodiments have been described as embodiments of the present invention, those having ordinary knowledge in this field can imagine many alternatives, modifications, and equivalents from these embodiments. Obviously, the present invention is intended to embrace all such alternatives, modifications and equivalents as fall within the spirit and scope of the invention as set forth in the appended claims.

For example, the cleaning means may have a plurality of blades or may be mainly made of silicone rubber.

The image bearing means may be in the form of an endless belt, and the photosensitive layer may contain fluorine or carbon, may be negatively charged, or may be mainly composed of OPC, selenium, or cadmium sulfide. .

The toner may be mixed with a carrier, non-magnetic, or negatively charged.

Lastly, in order to highlight the usefulness of the present invention, a comparative example according to the prior art will be described. However, a difference from the first embodiment will be omitted.

Comparative Example 1 That is, in this comparative example, the potential of the magnetic roller 83 was set to be higher than the surface potential of the photoreceptor, that is, the toner in the staying portion S was not transferred to the photosensitive drum 1. I have.

Specifically, there is no means for applying the bias voltage Vrm to the magnetic roller 83, and the pre-exposure amount Ipe is not increased.

An image was output under the same conditions as in the first embodiment, and the results of Comparative Example 1 in which each evaluation was performed are shown in Table 1 above.

In Comparative Example 1, the cleaning is significantly reduced due to the turning-up or breakage of the blade 81.

[0103]

According to the present invention, it is possible to prevent the plate-shaped member mainly composed of an elastic material from being turned up and damaged, which constitutes the cleaning means, and to maintain the cleaning performance of the latent image carrying means for a long period of time. Is provided simply and inexpensively.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a cleaning device according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of a cleaning device according to a second embodiment of the present invention.

FIG. 3 is a sectional view of the image forming apparatus according to the first embodiment of the present invention.

FIG. 4 is a perspective view of the magnetic roller of FIG. 1;

FIG. 5 is a perspective view of the blade of FIG. 1;

FIG. 6 is a diagram illustrating turning of a blade.

FIG. 7 is a schematic diagram showing a drive system of a photosensitive drum and a cleaning device.

FIG. 8 is a sectional view of a conventional cleaning device.

FIG. 9 is a diagram illustrating the sharing of driving means of the image forming apparatus.

FIG. 10 is a diagram illustrating the sharing of driving means of the image forming apparatus.

FIG. 11 is a diagram illustrating the sharing of the driving unit of the image forming apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Latent image holding means 8 ... Cleaning device 81 ... Plate member 83 ... Magnetic field generating means m ... Transfer material M ... Drive means N ... Press contact part t ... Powder toner

Claims (5)

[Claims] A latent image carrier on which a latent image is formed; developing means for developing the latent image formed on the latent image carrier; and toner remaining on the latent image carrier remaining after transfer is removed. A cleaning means, wherein the cleaning means comprises: a first plate-shaped member pressed against the latent image carrier; and the latent image carrier upstream of the plate member with respect to a rotation direction of the latent image carrier. An image forming apparatus comprising: a rotatable magnetic field generating means disposed with a gap G1 provided therein; and a second plate-shaped member disposed with a gap G2 provided in the magnetic field generating means. Means for transferring a part of the toner near the magnetic field generating means to the latent image carrier during the period when the latent image carrier is rotating and the magnetic field generating means is not rotating, and Characterized in that the image forming apparatus is moved toward a pressure contact portion with the shape member. Location. 2. The apparatus according to claim 1, wherein the cleaning unit transfers the toner from the vicinity of the magnetic field generating unit to the latent image carrier by changing a potential of the latent image carrier. The image forming apparatus as described in the above. 3. The apparatus according to claim 1, wherein the cleaning unit transfers the toner from the vicinity of the magnetic field generating unit to the latent image carrier by changing a potential of the magnetic field generating unit. Image forming apparatus. 4. The image forming apparatus according to claim 1, wherein a driving unit of the magnetic field generating unit in the cleaning unit is different from a driving unit of the latent image holding unit. . 5. The image forming apparatus according to claim 1, wherein the gaps G1 and G2 satisfy the following equation. 250 (μm) ≦ G1-G2 ≦ 500 (μm)