CN1230720C - Image forming device and image carrier assembly - Google Patents

Abstract

The present invention relates to an image forming device and an image carrier assembly in the same. An electrifying roller 14 is brought into contact with the coating part 61 of the drum 5 through a tape members 18, and a gap G is formed between the electrification effective width Wac of the roller and the surface of the drum. Thus, the wear or the damage of the member is made smaller than in the case the member is brought into contact with a non-coating part 62 formed of harder material than the coating part 61. Even though the thickness of the member is set to <=100 mum, the member is not worn drastically. The gap G is greater than the sum of an axial flatness D of the surface of the drum and an axial flatness E of the surface of the electrifying roller. So that the electrification effective width Wac of the roller is prevented from coming into contact with the drum. The electrification performance is prevented from lowering and the good image is gained.

Description

Image forming device and image carrier unit

technical field

The present invention relates to an image forming apparatus provided with an image carrier and a charging device, and an image carrier assembly incorporated in the image forming apparatus. The image carrier includes a coated portion for forming a photosensitive layer and A non-coated portion formed of a material harder than the coated portion, the above-mentioned charging device includes a charging member that charges the coated portion of the image carrier, and the image area portion of the charging member is opposed to the charged surface of the image carrier They are placed close to each other to form a predetermined gap, and a voltage is applied between the charging member and the image carrier to charge the above-mentioned charged surface.

Background technique

Conventionally, there is a non-contact charging device in which the portion of the charging member forming an image area, that is, the effective charging width portion, is placed close to the surface of a photoreceptor as an image carrier, and a voltage is applied between the charging member and the photoreceptor. , so that the surface of the photoreceptor drum is charged.

Examples of such charging devices include JP-A-3-240076, JP-A-4-360167, and JP-A-5-107871. It describes a non-contact charging device. In this non-contact charging device, for example, a belt is formed by attaching a bush or a winding belt to both ends of a roller portion formed of rubber or the like of a charging roller as a charging member. The member becomes a convex portion so that the other portions at both ends of the decharging roller are in a non-contact state with respect to the surface of the photoreceptor as an image carrier, and the photoreceptor is charged in this state.

In this charging device, the part corresponding to the image formation area of the charging member does not contact the surface of the photoreceptor, so the attached matter such as toner adhering to the surface of the photoreceptor does not transfer to the charging member, and the charging member is less likely to be dirty. .

Fig. 18 shows an example of the charging roller. In this charging roller 114, a conductive elastic portion 117 is provided on the outer periphery of, for example, a metal core 116 made of stainless steel, and resin belt members 118, 118 are wound around both ends of the elastic portion 117 in the circumferential direction and fixed integrally.

Both ends of the metal core 116 are pressurized toward the photoreceptor drum 105 with a predetermined pressurizing force by pressurizing springs 119 , 119 via slide bearings 130 , 130 . Thus, the belt members 118 and 118 on both sides of the charging roller 114 are in contact with the surface of the photoreceptor drum 105, and the effective charging width Wac of the elastic portion 117 forms a gap G corresponding to the thickness of the belt member 118 with respect to the surface of the photoreceptor drum 105. , become a non-contact state.

However, as described above, a belt member having a predetermined thickness is integrally fixed to both ends of the charging roller, and by bringing the belt member part into contact with the photoreceptor, a predetermined gap is formed between the charging roller and the surface of the photoreceptor at an effective charging width portion, and the In such a non-contact charging device, there is a problem of belt member wear.

That is, if the gap G shown in FIG. 18 is too wide, predetermined charging performance cannot be obtained. Therefore, the gap G needs to be set to, for example, about 100 μm or less. In this way, the thickness of the belt member becomes very thin below 100 μm.

However, since the outer peripheral surface of the belt member continues to rotate while contacting the surface of the photoreceptor, abrasion of the outer peripheral surface cannot be avoided.

If the belt member wears out early and the gap becomes zero, the charging roller contacts the surface of the photoreceptor over the effective charging width. In this way, residual toner, etc. on the photoreceptor will be transferred to the effective charging width of the charging roller, causing poor charging due to contamination.

In addition, even if the charging member and the photoreceptor are not in contact with the image forming area, the surface of the charging member and the photoreceptor has fine unevenness, that is, there is an unavoidable flatness in the axial machining accuracy (the distance from the bottom of the concave portion to the convex portion The numerical value represented by the height of the top, when the object is flat, becomes a problem of flatness), therefore, sometimes the charging member and the photoreceptor surface are in contact with each other due to the straightness or flatness of the surface of the photoreceptor.

In that case, even if it is a non-contact charging device, when the surface of the charged part is mostly in contact with the surface of the carrier, the dirt attached to the surface of the carrier will be transferred to the surface of the charged part, which will reduce the charging performance. low.

Contents of the invention

The present invention was made in view of the above-mentioned problems in the prior art. The first object of the present invention is to obtain high-quality images by maintaining good charging performance for a long period of time by making gap management members such as belt members less likely to wear.

The second object of the present invention is to prevent the dirt adhering to the surface of the image carrier from being transferred to the surface of the charging member by preventing the charging member such as the charging roller from contacting the surface of the image carrier such as the photoreceptor in the image forming area, so that it can be used for a long time. Maintain good charging performance and get high-quality images.

In order to achieve the above object, the present invention proposes an image forming device, which is provided with an image carrier and a charging device. The non-coated parts on both sides, the above-mentioned charging device includes a charging member that makes the coated part of the image carrier charged; it is characterized in that the gap management member is in contact with the non-charged area of the coated part of the above-mentioned image carrier, The charging member is brought into contact with the surface of the image carrier through a gap management member, and a predetermined gap is formed between the charging member and the image carrier at an effective charging width portion of the charging device.

The image forming apparatus according to the present invention is further characterized in that a cleaning device is provided for cleaning with a predetermined cleaning width by slidingly contacting the coated part of the image bearing body so that the gap management member is positioned within the cleaning width of the cleaning device. Inside.

The image forming apparatus according to the present invention is further characterized in that the cleaning width is up to the outer side of the outer edge of the gap management member.

The image forming apparatus according to the present invention is further characterized in that a cleaning device is provided for cleaning with a predetermined cleaning width by slidingly contacting with the coating part of the image bearing body so that the cleaning width of the cleaning device is within the range of the gap management. inside of the part.

According to the image forming apparatus of the present invention, it is also characterized in that a cleaning member swing mechanism is provided, so that the cleaning member of the above-mentioned cleaning device swings in a direction perpendicular to the sliding direction of the cleaning member relative to the carrier, and will be cleaned by the cleaning member. The cleaning swing area width of the cleaning member swinging by the member swing mechanism is set as the cleaning width.

The image forming apparatus according to the present invention is further characterized in that the cleaning means is a means for slidably contacting the cleaning blade with the coated portion of the image carrier to clean the coated portion.

According to the image forming apparatus of the present invention, it is also characterized in that a transfer member is provided to transfer the visible image formed on the surface of the above-mentioned image carrier onto a transfer material such that the effective transfer width of the transfer member is less than The effective charging width of the charging device described above is short.

According to the image forming apparatus of the present invention, it is also characterized in that a developing device is provided to develop the latent image on the above-mentioned image bearing body into a visible image by a developer, so that the developing width of the developing device is larger than the effective charging of the above-mentioned charging device. The width is short.

The image forming apparatus according to the present invention is further characterized in that a developing device is provided for developing the latent image on the image bearing member into a visible image with a developer such that the developing device has a developing width shorter than an effective transfer width.

The image forming apparatus according to the present invention is further characterized in that the developer is a two-component developer using a toner and a carrier.

The image forming apparatus according to the present invention is further characterized in that the cleaning width is longer than the effective charging width.

According to the image forming apparatus of the present invention, it is also characterized in that a cleaning member swing mechanism is provided, so that the cleaning member of the above-mentioned cleaning device swings in a direction perpendicular to the sliding direction of the cleaning member relative to the carrier, through which the cleaning member The movement limit positions of the two sides of the cleaning member oscillating by the oscillating mechanism are respectively located outside the effective charging width.

The image forming apparatus according to the present invention is further characterized in that the charging member is a charging roller having elastic portions formed at portions other than both ends of the outer peripheral surface of the metal shaft, and the gap management member is respectively fixed to both ends of the elastic portion. In the pair of belt members of the above-mentioned portion, the width between the inner sides of the pair of belt members becomes the effective charging width.

The image forming apparatus according to the present invention is further characterized in that the belt member has a thickness of 100 μm or less.

The image forming apparatus according to the present invention is further characterized in that the pair of belt members are respectively wound and fixed on both ends of the elastic portion in the circumferential direction, and the two ends in the circumferential direction do not overlap with each other, and there is no belt member at all positions of a circle. A little part with parts.

The image forming apparatus according to the present invention is further characterized in that the circumferential ends of the pair of belt members are respectively cut obliquely so that the edges of the cuts face each other, and a gap is formed between the ends of the cuts.

The image forming apparatus according to the present invention is further characterized in that oblique portions are cut at both circumferential ends of the pair of belt members, and the angle of inclination of the oblique cut lines relative to the side edges of the belt members is approximately 45 degrees.

The image forming apparatus according to the present invention is further characterized in that the above-mentioned charging roller is arranged such that both ends of the metal shaft are away from the non-coating portion, and is arranged so that when a voltage is applied between the metal shaft and the image bearing body, the charging roller is arranged so that both ends of the metal shaft are separated from the non-coating portion. The position where leakage does not occur from the end to the non-coated portion of the image carrier.

The image forming apparatus according to the present invention is further characterized in that the charging member is a charging roller having elastic portions formed at portions other than both ends of the outer peripheral surface of the metal shaft, and the gap management member is a metal shaft respectively attached to the charging roller. rollers at both ends.

In order to achieve the above object, the present invention proposes another image forming device, which is provided with an image carrier comprising a photosensitive layer and a charging device comprising a charging member, and the charging member charges the above-mentioned image carrier; it is characterized in that:

The gap management member is in contact with the non-charged area of the above-mentioned image carrier, and the above-mentioned charging member is contacted with the surface of the above-mentioned image carrier through the gap management member, and a predetermined gap is formed between the above-mentioned charging member and the image carrier;

A cleaning device is provided to clean with a predetermined cleaning width by slidingly connecting with the above-mentioned image carrier;

The aforementioned gap management member is located within the cleaning width of the cleaning device.

In order to achieve the above object, the present invention proposes another image forming device, which is provided with an image carrier and a charging device, and the charging member is arranged so that at least the image forming area part forms a predetermined gap with respect to the surface of the image carrier, and the voltage is applied to the surface of the image carrier. Between the charging member and the image carrier, the image carrier is charged; it is characterized in that the flatness of the surface of the image carrier is A, and the surface of the charging member facing the image carrier is When the flatness of the above is set to B, and the above-mentioned gap is set to G, the following relationship is satisfied: A+B<G.

The image forming apparatus according to the present invention is further characterized in that the predetermined gap is formed by bringing a positioning member provided outside the image formation area of the charging member into contact with the surface of the image carrier.

The image forming apparatus according to the present invention is further characterized in that the predetermined gap is formed by a positioning member interposed between the charging member and the surface of the image carrier, and the thickness of the positioning member becomes the predetermined gap.

In order to achieve the above object, the present invention proposes yet another image forming device, which is provided with an image carrier and a charging device, so that the roller-shaped charging member passes through the positioning member and the surface of the cylindrical image carrier arranged outside the image forming area. Contact, forming a predetermined gap in the image forming area between the charging member and the image carrier, by applying a voltage between the charging member and the image carrier, the image carrier is charged; it is characterized in that the above-mentioned When the axial straightness of the surface of the carrier is D, the axial straightness of the roller surface of the charging member is E, and the predetermined gap is G, the following relationship is satisfied: D+E<G.

In order to achieve the above object, the present invention proposes an image carrier assembly, which is characterized in that it is an image carrier assembly installed in the above-mentioned image forming apparatus of the present invention, and the image carrier and the charging member are set as One.

Effects of the present invention will be described below.

According to an image forming apparatus of an aspect of the present invention and an image carrier unit incorporated in the above image forming apparatus, the gap management member is in contact with the coated portion of the image carrier, and is located between the charging member and the surface of the image carrier. Since the predetermined gap is formed, the wear and damage of the gap management member can be reduced compared to the case where the gap management member is in contact with the non-coated portion formed of a material harder than the coated portion. Therefore, the gap between the charging member and the image carrier can be kept substantially constant over a long period of time.

According to the image forming apparatus of one aspect of the present invention, the gap management member is located within the cleaning width of the cleaning device and contacts, so even if the cleaning width region such as the surface of the carrier is worn due to the long-term sliding of the cleaning device, the gap management member contacts The wearing part can usually keep a constant gap between the charging member and the surface of the image carrier. In this way, good images can be obtained even after a long period of operation.

According to the image forming apparatus of one aspect of the present invention, the coating portion forming the photosensitive layer of the image carrier is slid by the cleaning device, and after a long period of operation, the cleaning width area is subject to wear. If the predetermined use time is reached, the image carrier reaches In this image forming apparatus, the cleaning width of the cleaning device is located inside the gap management member, and the coated portion of the contact portion of the gap management member will not be worn by the cleaning device.

Therefore, when the cleaning width area of the coated part is gradually worn away by the cleaning device, the gap between the charging member and the surface of the image carrier gradually becomes larger, and a charging failure occurs. Then, it can be judged that the life of the image carrier has been reached by using the timing of occurrence of the charging failure.

Generally, when the cleaning width reaches the position of the gap management member, transfer residual toner recovered from the image carrier is spilled from both ends of the cleaning device, and after it adheres to the image carrier again, if it adheres to the gap management member However, as mentioned above, if the cleaning width is located inside the gap management member, the recovered toner, etc. spilled from the cleaning device is less likely to adhere to the gap management member. On, the gap can be prevented from increasing.

According to an image forming apparatus of an aspect of the present invention, the cleaning member is swung by the cleaning member swing mechanism, so paper dust and the like can be prevented from being continuously sandwiched between the cleaning member and the surface of the image carrier, and the cleaning member will not swing to Outside the coated area, it is possible to prevent curling and early wear and tear of the cleaning component caused by the joint portion between the cleaning component and the coated or non-coated portion of the image carrier or the non-coated portion slipping.

According to the image forming apparatus of one aspect of the present invention, the cleaning blade of the cleaning device will not slip with the coated portion of the image carrier, the joint portion between the non-coated portion or the non-coated portion, therefore, can prevent The cleaning blade is curled while preventing premature wear of the cleaning blade.

In the image forming apparatus according to one aspect of the present invention, in general, the charging potential is unstable near both ends of the effective charging width of the surface of the carrier, and the developer is likely to adhere there. The short effective charging width prevents the developer adhering to the vicinity of both ends of the effective charging width from transferring to the transfer member.

According to an image forming apparatus according to one aspect of the present invention, since the developing width of the developing device is shorter than the effective charging width of the charging device, it is possible to prevent the developer from adhering to the vicinity of both ends of the effective charging width of the image carrier. Therefore, it is possible to prevent the developer from entering between the gap management member and the surface of the image carrier to prevent the above-mentioned gap from becoming large, and at the same time, problems caused by the developer adhering to the vicinity of both ends of the effective charging width do not occur.

According to an image forming apparatus of an aspect of the present invention, since the developing width is shorter than the effective transfer width, and the effective transfer width is shorter than the effective charging width, the developer is less likely to adhere to both ends of the effective charging width on the image carrier. near the Ministry.

According to an image forming apparatus according to an aspect of the present invention, even if an attaching matter such as a developer adheres to both end portions of the effective charging width on the image carrier, this portion can be cleaned by the cleaning device, and damage caused by the aforementioned attaching matter can be prevented. Influence.

According to an image forming apparatus of an aspect of the present invention, it is possible to prevent paper dust or the like from being constantly caught between the cleaning member and the surface of the image carrier, and at the same time, even if the attachments such as developer are attached to the image carrier, the effective charging width is doubled. The end portion, which can also be cleaned by the cleaning member, can prevent the above-mentioned bad influence caused by the attached matter.

According to an image forming apparatus according to an aspect of the present invention, the gap management member is a pair of belt members, which are easily fixed by being wound around both ends of the elastic portion of the charging member. Therefore, workability at the time of mounting the gap management member is improved.

In the image forming apparatus according to one aspect of the present invention, the belt member is very thin with a thickness of 100 μm or less, and when it comes into contact with the surface of the image carrier, the ratio of the reduced thickness to the original thickness is very large. Therefore, by bringing the belt member into contact with the coated portion, which is softer than the non-coated portion, the friction is reduced, which is very effective.

According to an image forming apparatus according to an aspect of the present invention, a pair of belt members are respectively wound and fixed on both ends of the elastic portion in the circumferential direction, and the two ends in the circumferential direction do not overlap with each other, and there is no belt member missing at all positions in a circle. Therefore, even if the two ends in the circumferential direction are in contact with the image carrier, the image carrier will not periodically fall between the edges of the two ends of the belt member in the circumferential direction. Therefore, it is possible to prevent microvibration that occurs when the image carrier falls between the edge edges of the two circumferential ends.

According to an image forming apparatus of an aspect of the present invention, the circumferential ends of a pair of belt members are respectively cut obliquely so that the edge edges of the cutouts face each other, and a gap is formed between the edge edges of the two ends of the cutout. The dimensional control of the length in the winding direction is not strict, and it is also possible to prevent the two ends of the belt member from overlapping each other in the circumferential direction.

According to an image forming apparatus according to an aspect of the present invention, oblique portions are cut at both ends of the pair of belt members in the circumferential direction. The tip is not easy to peel off, and the contact width between the seam portion of the belt member and the image carrier is increased.

According to an image forming apparatus according to an aspect of the present invention, the charging roller is arranged such that both ends of the metal shaft are away from the non-coating portion, and is arranged so that when a voltage is applied between the metal shaft and the image carrier, the charging roller is arranged so that Since there is no position where leakage occurs in the non-coated part of the carrier, leakage from the metal axis of the charging roller to the non-coated part of the carrier can be prevented, and good charging performance can be obtained.

According to an image forming apparatus according to an aspect of the present invention, the gap management member is rollers respectively attached to both ends of the metal shaft of the charging roller, so that when the charging member is a charging roller provided with an elastic portion, the above-mentioned rollers are brought into contact with the charging roller as shown in FIG. On the surface of the carrier, a predetermined gap can be formed between the effective charging width portion of the charging member and the surface of the image carrier, and the belt member does not wind around both ends of the elastic portion in the case of a belt-shaped gap management member.

When the belt-shaped gap management member is wound around the elastic part of the charging roller, the elastic part of the winding gap management part deforms due to the pressing force of the charging roller toward the image carrier side, so that the above-mentioned gap is narrowed, and the above-mentioned roller gap management member This problem can be prevented.

According to the image forming apparatus of one aspect of the present invention, the gap management member is located within the cleaning width of the cleaning device and contacts, so even if the cleaning width region such as the surface of the carrier is worn due to the long-term sliding of the cleaning device, the gap management member contacts The wearing part can usually keep a constant gap between the charging member and the surface of the image carrier. In this way, good images can be obtained even after a long period of operation.

According to an image forming apparatus of an aspect of the present invention, the flatness of the surface of the image carrier is defined as A, the flatness of the surface of the charging member facing the image carrier is B, and the surface of the charging member and the image carrier is The gap G defined between them is greater than the sum of A and B above, and the image formation area of the image carrier does not contact the charging member.

Therefore, even when transfer toner or the like remains on the surface of the image carrier, the dirt does not transfer to the charging member, and good charging performance can be obtained, resulting in high-quality images.

According to an image forming apparatus according to an aspect of the present invention, a predetermined gap is formed by contacting a positioning member provided outside an image formation area of a charging member, which is a charging roller provided with a conductive rubber roller portion, to the surface of an image carrier. When a band-shaped positioning member is wound around both ends of the conductive rubber roller to form a gap, the elastic portion of the winding gap management member deforms due to the pressure of the charging roller toward the image carrier, thereby narrowing the gap. There is a possibility that the charging roller may come into contact with the surface of the image carrier, but the image forming apparatus described above can prevent such a problem.

According to the image forming apparatus of one aspect of the present invention, the predetermined gap is formed by the positioning member sandwiched between the charging member and the surface of the image carrier, and the thickness of the positioning member becomes the above-mentioned predetermined gap. Control can be easily performed only by controlling the thickness of the positioning part.

According to an image forming apparatus of an aspect of the present invention, when the charging member is a roller and the image bearing member is cylindrical, the image forming region of the image bearing member is not in contact with the charging member. Even if transfer toner, etc. remain on the surface, the dirt will not transfer to the charging parts, and good charging performance can be obtained, resulting in high-quality images.

According to one aspect of the present invention, the image carrier unit is formed such that the image carrier and the charging member are integrally formed, and the workability at the time of replacement or maintenance is improved.

Description of drawings:

1 is a schematic diagram of a charging roller and a photoreceptor provided in an image forming apparatus according to a first embodiment of the present invention;

Fig. 2 is an enlarged view of one end side of the charging roller;

FIG. 3 is an overall configuration diagram of a color compact printer as the image forming apparatus;

Fig. 4 is a structural diagram of a photoreceptor assembly provided in the miniature printer;

Fig. 5 is a structural diagram of a writing component provided in the small printer of Fig. 3;

Fig. 6 is a schematic diagram of the relative comparison of the width relationship of each part of the imaging system of the small printer of Fig. 3;

FIG. 7 is a schematic diagram similar to FIG. 6 for comparing the width relationship of each part of the imaging system of the image forming apparatus according to the second embodiment of the present invention;

FIG. 8 is a schematic diagram for explaining a cleaning member swing mechanism provided in the image forming apparatus;

9 is a schematic diagram similar to FIG. 6 of an image forming apparatus in which the cleaning width of the cleaning member is positioned inside a pair of belt members, relating to a third embodiment of the present invention;

Fig. 10 relates to the fourth embodiment of the present invention, and is a schematic diagram similar to Fig. 7 for comparing the width relationship of each part of the imaging system of the image forming apparatus according to the fourth embodiment of the present invention;

11 relates to a fifth embodiment of the present invention, and is a schematic diagram similar to FIG. 6 of an image forming apparatus in which the cleaning width of the cleaning member is located outside the outer edges of a pair of belt members;

12 is a schematic diagram similar to FIG. 7 of the image forming apparatus in which the cleaning width of the swing cleaning blade is located outside the outer edge edges of a pair of belt members, relating to the sixth embodiment of the present invention;

Fig. 13 relates to the seventh embodiment of the present invention, and is a front view of the seventh embodiment using the gap management component as a roller;

Fig. 14 is an explanatory view of the axial flatness of the surface of the photoreceptor;

Fig. 15 is an explanatory view of the axial flatness of the surface of the conductive rubber roller portion of the charging roller;

Fig. 16 is a schematic view showing a state where the tip of the photoreceptor and the tip of the conductive rubber roller face each other;

17 relates to the eighth embodiment of the present invention, and is a schematic diagram of the vicinity of the imaging section of an image forming apparatus in which the image carrier is a belt-shaped photoreceptor belt;

Fig. 18 is a schematic diagram showing an example of a conventional charging roller.

Detailed ways

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

1 is a schematic diagram of a charging roller and a photoreceptor drum provided in an image forming apparatus according to a first embodiment of the present invention, FIG. 2 is an enlarged view of one end side of the charging roller, and FIG. The overall configuration diagram of the printer.

The color compact printer shown in FIG. 3 as an image forming device is a four-drum full-color electrophotographic image forming device, and four photoreceptor assemblies 2A, 2B, 2C, and 2D as image carrier assemblies are housed in the device body 1. , they can be installed and disassembled relative to the device body 1 respectively.

In the approximate center of the device body 1 of the small printer, three transfer belts are mounted on several rollers, which can rotate in the direction A indicated by the arrow.

The photoreceptor assemblies 2A, 2B, 2C, and 2D are arranged such that the photoreceptor drums 5 respectively provided in the photoreceptor assemblies 2A, 2B, 2C, and 2D contact the upper surface of the transfer belt 3 .

In addition, corresponding to the photoreceptor assemblies 2A, 2B, 2C, and 2D described above, developing devices 10A, 10B, 10C, and 10D using toners of different colors are disposed.

A writing unit 6 is disposed above the photoreceptor units 2A, 2B, 2C, and 2D, and a double-sided unit 7 is disposed below the photoreceptor units 2A, 2B, 2C, and 2D.

On the left side of the device body 1 of the small printer (see FIG. 3 ), there is a reversing unit 8 that reverses and discharges the transfer paper P after image formation, or conveys the transfer paper P to the duplex unit 7 .

A fixing device 9 is provided between the transfer belt 3 and the reverse assembly 8 for fixing the image transferred on the transfer paper.

On the downstream side of the fixing device 9 along the conveying direction of the transfer paper, the reverse conveying path 20 is branched, and the transfer paper P conveyed here can be discharged onto the paper discharge tray 26 through a pair of discharge rollers 25 . .

In addition, paper feeding cassettes 11 and 12 are arranged in the upper and lower stages of the lower part of the device main body 1, respectively, and transfer paper P of different sizes can be accommodated.

On the right side of the device body 1, a manual paper feed tray 13 is provided, which can be opened and closed in the direction of arrow B, and by opening the manual paper feed tray 13, paper can be manually fed from there.

The photoreceptor assemblies 2A, 2B, 2C, and 2D have the same structure. The photoreceptor assembly 2A is used to form an image corresponding to yellow, the photoreceptor assembly 2B is used to form an image corresponding to magenta, and the photoreceptor assembly 2C is used to form an image corresponding to cyan. The photoreceptor assembly 2D is used to form an image corresponding to black. In addition, they are arranged at regular intervals along the conveyance direction of the transfer paper.

As shown in Figure 4, the photoreceptor assemblies 2A, 2B, 2C, and 2D are respectively integrally formed components of the charging roller 14, the photoreceptor drum 5, the cleaning blade 47, and the brush roller 15, which can be compared to the device body shown in Figure 3 1 loading and unloading. The above-mentioned charging roller 14 is a part of the charging device 4 as a charging means, and the above-mentioned photosensitive drum 5 as an image carrier is an organic photoconductor, and the surface of the photosensitive drum 5 is charged by the above-mentioned charging roller 14, and then exposed to form static electricity. The latent image, the cleaning blade 47 and the brush roller 15 constitute cleaning means for cleaning the surface of the photoreceptor drum 5 .

As shown in FIG. 1 , the charging device 4 is arranged so that the effective charging width Wac portion of the charging roller 14 as a charging member is close to the charged surface (surface) of the photoreceptor drum 5 by a structure described later, and a voltage is applied to the charging roller 14. Between the photoreceptor drum 5 and the photoreceptor drum 5 , the charged surface of the photoreceptor drum 5 is charged.

The charging roller 14 of the charging device 4 can be formed by, for example, the following method: a metal core 16 is formed by nickel-plating the surface of steel, and a conductive rubber roller portion 17 is formed on the outer peripheral surface of the metal core 16 except for both ends. The elastic part can be made of, for example, epichlorohydrin rubber, and the volume specific resistance value is set to 1×10 3 to 1×10 8 Ω·cm.

At both ends of the conductive rubber roller portion 17, there are belt members 18, 18 as gap management members, which are adhesive tapes with an adhesive surface formed on one side, and can be made of, for example, polyester or polyethylene terephthalate. The belt members 18, 18 are made of glycol ester, and are wound around both ends of the above-mentioned conductive rubber roller portion 17 in the circumferential direction with the bonding surface facing downward.

Fig. 2 shows a belt member 18 on one side. As shown in Fig. 2, it is fixed by bonding so that the end edges 18a, 18b at both ends of the circumferential direction of the belt member 18 do not overlap with each other, and along the axial direction indicated by arrow E, , there is no part without a little belt member 18 in all positions of a week.

Therefore, as shown in the figure, both ends of each belt member 18 are cut obliquely so that cut edges 18a, 18b face each other, and a gap S is formed between the edges 18a, 18b at both ends of the cut.

In addition, the inclination angles θ1 and θ2 of the edge edges 18 a and 18 b at both ends of the cutout with respect to the side edges of the belt member 18 are approximately 45 degrees.

In this way, if the inclination angles θ1 and θ2 of the edges 18a and 18b at both ends of the slit with respect to the side edges of the belt member 18 are approximately 45 degrees, the ends of the belt member 18 in the winding direction are less likely to be peeled off from the elastic portion 17. The contact width between the joint portion of the belt member 18 (where there is a gap S) and the photoreceptor drum can also be increased. Therefore, compared with the case where the above-mentioned inclination angles θ1 and θ2 are less than 45 degrees, the adhesion of the tip portions at both ends to the elastic portion 17 is lower. The relay gets bigger. Therefore, the sharp ends of both ends of the belt member 18 are not easily peeled off.

As shown in FIG. 4 , the belt members 18 and 18 at both ends of the charging roller 14 are in contact with the photosensitive drum 5 . The surface of the photoreceptor drum 5 is charged to form a charging device 4 .

As shown in FIG. 1 , both ends of the metal core 16 of the charging roller 14 are pressed against the photosensitive drum 5 with a predetermined pressing force by pressing springs 19 , 19 through sliding bearings 30 , 30 .

Instead of using the pressure roller 19 described above, both ends of the metal core 16 of the charging roller 14 may be brought into contact with the photoreceptor drum 5 by their own weight.

A driving gear 40 is fixed to the right end of the metal core 16 and transmits a driving force from a motor (not shown), so that the charging roller 14 and the photoreceptor drum 5 rotate at the same linear velocity.

The application of voltage to the charging roller 14 is to apply, for example, DC700V to the metal core 16 in a constant voltage control method, and at the same time, apply an AC voltage in a constant current control method.

In the charging roller 14, for example, the outer diameter of the metal core 16 is Φ9 mm, and the conductive rubber roller portion 17 is made of epichlorohydrin rubber, and the thickness of the rubber layer is 1.5 mm. As the belt member 18 wound around both ends of the conductive rubber roller portion 17, a belt having a width of 8 mm and a thickness of 25 to 125 μm is used in the present embodiment, for example. When the thickness of the belt member 18 is 100 μm or less, more stable charging performance can be obtained.

The hardness of the rubber used for the conductive rubber roller part 17 is about 77 degrees in the old JIS-A, and the sample hardness of the rubber itself is 50 degrees or more.

The photoreceptor drum 5 is driven to rotate in the direction of arrow C in FIG. 4 by the motor through the drum drive timing belt and the drum drive pulley (both not shown).

Each photoreceptor assembly 2A, 2B, 2C, 2D is provided with a cleaning blade 47 so that the front end of the cleaning blade 47 is in sliding contact with the coating part 61 (described in detail later) on the surface of the photoreceptor drum 5 for scraping and adhering. Toner and the like remain in the transfer on the coated portion 61 and are cleaned. The toner scraped off by the cleaning blade 47 moves to the side of the toner conveying screw 48 at the brush roller 15, and the recovered waste toner is conveyed to a predetermined waste toner storage portion by the rotation of the toner conveying screw 48.

Each photoreceptor unit 2A, 2B, 2C, 2D also makes a charging roller cleaner 49 made of, for example, a sponge contact the surface of the conductive rubber roller portion 17 of the charging roller 14, and the toner, dust, etc. floating in the machine adhere to the surface of the conductive rubber roller portion 17 of the charging roller 14. When the surface of the conductive rubber roller portion 17 is removed, the charging roller cleaner 49 can clean it.

Each photoreceptor assembly 2A, 2B, 2C, 2D is provided with a positioning main reference part 51, which is used as a reference when attaching and detaching relative to the device body 1. At the same time, the positioning sub-reference part 52, The positioning sub-reference part 53 on the back side of the paper is integrated with the bracket 50. When the photoreceptor assemblies 2A, 2B, 2C, and 2D are installed in the device body 1, the photoreceptor assemblies 2A, 2B can be reliably positioned according to the above-mentioned reference parts. , 2C, 2D are positioned at the designated installation position.

Each photoreceptor drum 5 of the photoreceptor assembly 2A, 2B, 2C, and 2D rotates in the direction of arrow C as described above, and its linear speed can be adjusted according to the black and white speed priority mode, the black and white image quality priority mode, the color speed priority mode, and the color image quality priority mode. Mode, Thick Paper·Transparency Film Mode and other medium modes are adjusted to three levels of 185mm/sec, 125mm/sec, and 62.5mm/sec.

In this photoreceptor unit, the brush roller 15 may be excluded, and the charging roller 14 and the photoreceptor drum 5 may be constituted as an integral unit.

The developing devices 10A, 10B, 10C, and 10D shown in FIG. 3 have the same structure, and only the toner used is different. The developing device 10A uses yellow toner, the developing device 10B uses magenta toner, the developing device 10C uses cyan toner, and the developing device 10D uses black toner.

The writing unit 6 shown in FIG. 5 adopts the laser diode mode, one for color, two for black and white, and two rotating hexagonal mirrors 22a, 22b are arranged on a polygonal mirror motor.

The light emitted from a laser diode (not shown) as a light source passes through the revolving hexagonal mirrors 22a and 22b driven by the polygon mirror motor 21 so that the scanning light for yellow, the scanning light for magenta, the scanning light for cyan, and the scanning light for black The scanning light is reflected separately left and right.

The scanning light for yellow and the scanning light for magenta respectively pass through the double-layer fθ lens 23, the scanning light for yellow is reflected by the reflector 27, passes through the long WTL24, and then passes through the reflectors 28 and 29 to irradiate the photoconductor drum of the photoconductor assembly 2A. 5 on.

The magenta scanning light is reflected by the mirror 31 , passes through the long WTL 32 , passes through the mirrors 33 and 34 , and is irradiated on the photosensitive drum 5 of the photosensitive unit 2B.

The scanning light for cyan and the scanning light for black pass through the double-layer fθ lens 35 respectively. The scanning light for cyan is reflected by the reflector 36, passes through the long WTL 37, and then passes through the reflectors 38 and 39 to irradiate the photoconductor drum 5 of the photoconductor assembly 2C. superior.

The black scanning light is reflected by the reflector 41 , passes through the long WTL 42 , passes through the reflectors 43 and 44 , and is irradiated on the photoconductor drum 5 of the photoconductor unit 2D.

The duplex unit 7 shown in Fig. 3 is made up of pairs of conveying guide plates 45a, 45b and several pairs of conveying rollers 46 (four pairs in this embodiment). When the pattern is formed, an image is first formed on one side, and then transported to the reverse transport path 54 of the reverse assembly 8, and the transfer paper P transported through the zigzag transport route is received, and then the transfer paper P is transported to the device. There are image forming portions of photoreceptor units 2A, 2B, 2C, and 2D.

The reversing assembly 8 is composed of several pairs of conveying rollers and several pairs of conveying guides. It reverses the transfer paper P when the above-mentioned double-sided image is formed, and transports it to the double-sided assembly 7, or transfers the transfer paper P after image formation. P is discharged out of the machine as it is, or the transfer paper P is reversed and discharged out of the machine.

Separate paper feeding units 55 and 56 for separating and feeding the transfer paper P one by one are respectively provided in the paper feeding units provided with the paper feeding cassettes 11 and 12 .

This compact printer adopts a roll curvature separation method using a transfer belt 3 , and four transfer prints are provided inside the transfer belt 3 , corresponding to the four photoreceptor drums 5 .

When the compact printer starts the image forming operation, each photoreceptor drum 5 rotates clockwise as shown in FIG. 3 . By applying a voltage between each photoreceptor drum 5 and the charging roller 14 of each charging device, the surface of each photoreceptor drum 5 is uniformly charged.

By the writing unit 6, laser light corresponding to a yellow image is irradiated on the charging surface of the photosensitive drum 5 of the photoreceptor assembly 2A, and laser light corresponding to a magenta image is irradiated on the charging surface of the photosensitive drum 5 of the photoreceptor assembly 2B. On the photoreceptor unit 2C, laser light corresponding to a cyan image is irradiated on the charging surface of the photoreceptor drum 5, and laser light corresponding to a black image is irradiated on the charging surface of the photoreceptor drum 5 of the photoreceptor unit 2D. Latent images corresponding to the respective colors are formed respectively.

The photoreceptor drum 5 rotates, and when the latent images reach the positions of the developing devices 10A, 10B, 10C, and 10D, they are developed there with yellow, magenta, cyan, and black toners to form four-color toner images.

On the other hand, the paper feeding cassette is selected from the paper feeding cassette 11 or 12, and the transfer paper in the selected paper feeding cassette is fed through the separation paper feeding section 55 or 56, and the registration roller 59 is arranged so as to be next to the photoreceptor assembly. Before 2A, the transfer paper is transported between the photoreceptor drum 5 and the transfer belt 3 of the photoreceptor assembly 2A at the correct time by the registration roller 59, so that the transfer paper is formed on each photoreceptor drum 5. The ink images are consistent.

At that time, the transfer paper P is positively charged by the suction roller 58 disposed near the entrance of the transfer belt 3 , and thus electrostatically attracted to the surface of the transfer belt 3 .

In the state where the transfer paper P is adsorbed on the transfer belt 3, the transfer belt 3 rotates in the direction of the arrow A, and the transfer paper P is transported in this direction while sequentially transferring yellow on the upper side of the transfer paper P. , magenta, cyan, and black ink images pass through the photoreceptor assembly 2D to form a four-color superimposed full-color ink image.

The transfer paper P is heated and pressurized in the fixing device 9 to melt and fix the ink image. After that, the transfer paper P is discharged to the paper discharge tray 26 on the upper part of the device body through the paper discharge path of the specified mode, or directly from the fixing device 9. The paper is directly discharged through the reversing assembly 8.

Or, when the double-sided image forming mode is selected, after being sent into the reverse conveying channel 54 in the above-mentioned reverse assembly 8, it is transported to the double-sided assembly 7 through the zigzag conveying route, and the paper is fed from there, and the photoreceptor is provided. The imaging parts of the modules 2A, 2B, 2C, and 2D are discharged after forming an image.

Thereafter, the above-described imaging process is repeated when formation of two or more images is instructed.

As shown in FIG. 1 , this compact printer is provided with a photosensitive drum 5 including a coated portion 61 forming a photosensitive layer and a non-coated portion formed of a material harder than the coated portion 61 on both sides thereof. 62 , 62 , the charging device 4 charges the part of the effective charging width Wac of the coating part 61 .

And, the charging roller 14 of the charging device 4 is in contact with the non-charging area of the coated portion 61 of the photoreceptor drum 5 through the belt members 18, 18, and the charging roller 14 and the photoreceptor drum are connected to each other in the effective charging width Wac portion of the charging device 4. A predetermined gap G is formed between the surfaces of the drum 5 .

Therefore, abrasion and damage to the belt members 18 can be reduced compared to a case where each belt member 18 is in contact with the non-coated portion 62 formed of a material harder than the coated portion 61 .

In order for the belt member 18 to have good charging performance, the thickness is set to 100 μm or less. Even if it is so thin, due to the above-mentioned structure, it is not easy to wear, and the gap G formed between the charging roller 14 and the surface of the photoreceptor drum 5 can be maintained for a long time, and good charging performance can be obtained. In this way, good image quality can be maintained over a long period of time.

FIG. 6 is a schematic diagram for comparatively comparing the width relationship of each part constituting the image forming system of the small printer shown in FIG. 3 .

Each part that constitutes the imaging system of the miniature printer shown in Fig. 3 and Fig. 4 has the width relation shown in Fig. 6, wherein, Wdo is the overall width of the longitudinal direction of the photoreceptor drum 5, and Wt is the coating of the photoreceptor drum 5 coating part 61. Width, Wnt is the non-coating width of the non-coating portion 62 of the photoreceptor drum 5, Wac is the effective charging width of the charging device 4, Wta is each belt width of the left and right belt members 18, 18, and Wde is the developing device 10A, 10B. , the developing width of 10C, 10D, Wte is the transfer effective width of the transfer device provided with the transfer belt 3, and Wc is the cleaning width of the cleaning blade 47.

That is, the cleaning blade 47 slides on the coated portion 61 of the photoreceptor drum 5 to clean the coated portion 61 so that the pair of belt members 18 and 18 are located within the cleaning width Wc of the cleaning blade 47 .

In this way, the coated portion 61 of the photoreceptor drum 5 is worn away after a long-term operation due to the sliding contact of the cleaning blade 47, and even in that case, the abraded portion is contacted by a pair of belt members 18, 18. , the gap G between the effective charging width Wac portion of the charging roller 14 shown in FIG. 1 and the surface of the photoreceptor drum 5 can be kept constant. In this way, good images can still be obtained even after long-term operation.

In this embodiment, the width between the inner sides of the pair of belt members 18 and 18 becomes the effective charging width Wac.

In addition, the transfer member is in contact with the coated portion 61 of the photoreceptor drum 5, and transfers the visible image formed on the surface of the photoreceptor drum 5 onto the transfer paper (transfer material), so that the transfer belt as the transfer member The transfer effective width Wte of 3 is shorter than the effective charging width Wac of the charging device 4 .

Thus, although the vicinity of both ends of the effective charging width Wac on the surface of the photoreceptor drum 5 tends to adhere to the developer due to the unstable charging potential, the effective transfer width Wte is shorter than the effective charging width Wac, preventing the developer from adhering to both ends of the effective charging width Wac. The developer (toner and carrier in the case of a two-component developer) near the outside of the end is transferred to the transfer belt 3 .

Furthermore, the developing devices 10A, 10B, 10C, and 10D develop the latent image on the photoreceptor drum 5 into a visible image with the developer, so that the developing width of the developing devices 10A, 10B, 10C, and 10D is shorter than the effective charging width Wac.

This prevents the developer from adhering to the vicinity of both ends of the effective charging width Wac on the photoreceptor drum 5 . Therefore, it is possible to prevent the developer from entering between the belt member 18 and the surface of the photoreceptor drum 5 as described in FIG.

The development width Wde is made shorter than the transfer effective width Wte, so that the developer is less likely to adhere to the vicinity of both ends of the effective charging width Wac on the photoreceptor drum 5 .

When the developer is a two-component developer using a toner and a carrier, it is possible to prevent both the toner and the carrier from adhering to the vicinity of both ends of the effective charging width Wac of the photoreceptor drum 5 .

By making the cleaning width Wc wider than the effective charging width Wac, even if the developer etc. adhere to the both ends of the effective charging width Wac on the photoreceptor drum 5, the parts are cleaned by the cleaning blade 47, and the adhesion caused by the adhesion can be prevented. bad influence.

FIG. 7 relates to the second embodiment of the present invention, and is a schematic diagram similar to FIG. 6 for comparing the width relationship of each part of the imaging system of the image forming apparatus according to the second embodiment of the present invention. FIG. 8 is for explaining the configuration of the image forming apparatus There is a schematic diagram of the swing mechanism of the cleaning part. "Wcb" refers to the width of the cleaning blade.

The embodiment shown in Fig. 8 is only different from the embodiment in Fig. 6 in that the cleaning scraper 47 swings in the direction of arrow F, and the other structures are the same as those of the miniature printer illustrated in Fig. 1-Fig. 6. Therefore, the overall diagram of the miniature printer and description omitted.

As shown in Figure 8, the small-sized printer as an image forming device of this embodiment is provided with a cleaning member swing mechanism 70, which can make the cleaning blade 47 of the cleaning member as a cleaning means swing in the direction of arrow F, and the above-mentioned F direction is related to the cleaning. The scraper 47 is perpendicular to the sliding direction of the photoreceptor drum 5 .

The cleaning member swing mechanism 70 is composed of a blade holding member 71 , a cam 72 , a compression spring 73 and a motor 74 . The scraper holding member 71 holds the cleaning scraper 47 and can swing in the direction of arrow F; a protruding portion 71a is formed at the left end of the scraper holding member 71, and the cam surface of the above-mentioned cam 72 is in sliding contact with the hemispherical portion at the front end of the protruding portion 71a The compression spring 73 pushes the scraper holding member 71 so that the hemispherical portion at the front end of the protruding portion 71a presses against the cam surface of the cam 72 ; the motor 74 rotates the cam 72 .

When the cam 72 is rotated once, the cleaning blade 47 swings and reciprocates once together with the blade holding member 71 . The cleaning swing region width Wsc of the cleaning blade 47 swinged by the cleaning member swing mechanism 70 is defined as the cleaning width, which is located in the coating portion 61 of the photoreceptor drum 5. As shown in FIG. 7, a pair of belts The members 18, 18 (arranged at the position of the tape width Wta) are arranged within the cleaning swing area width Wsc.

According to this embodiment, the cleaning blade 47 is not in sliding contact with the coating portion 61 of the photoreceptor drum 5, the joint portion of the non-coating portion 62, and the non-coating portion, so the cleaning blade 47 can be prevented from curling, and at the same time, Can prevent its early wear and tear.

In this embodiment, the movement limit positions (left end and right end positions of the cleaning swing area width Wsc) of both sides of the cleaning blade 47 oscillated by the cleaning member oscillating mechanism 70 are set outside the effective charging width Wac.

Therefore, even if attachments such as developer adhere to both end portions of the effective charging width Wac on the photoreceptor drum 5 , they can be cleaned by the cleaning blade 47 , and adverse effects of the attachments can be prevented.

9 is a schematic diagram similar to FIG. 6 of an image forming apparatus in which a cleaning width of a cleaning member is located inside a pair of belt members, relating to a third embodiment of the present invention. The small printer as an image forming apparatus is only different from the small printer described in FIGS. , use the symbols used in Fig. 1-Fig. 6 as needed for description.

In the compact printer of this embodiment, the cleaning width Wc of the cleaning blade 47 is located inside the pair of side belt members 18, 18 (disposed at the left and right belt width Wta positions in FIG. 9).

Therefore, in this embodiment, the coating portion 61 (located in the coating width Wt portion) forming the photosensitive layer on the surface of the photoreceptor drum 5 is in sliding contact with the cleaning blade 47, and the cleaning blade 47 will wear out over a long period of operation in the cleaning width Wc area. On the other hand, since the belt members 18 and 18 on both sides are respectively located outside the cleaning width Wc of the cleaning blade 47, the coated portion 61 of the portion where the belt members 18 and 18 meet is not abraded by the cleaning blade 47. .

Therefore, as the cleaning blade 47 gradually wears away the cleaning width Wc area of the coating portion 61, the gap G between the charging roller 14 and the surface of the photoreceptor drum 5 illustrated in FIG. Poor charging occurred. Therefore, in this compact printer, it can be determined that the photoreceptor drum 5 has reached the end of its life by using the time when the charging failure occurs.

Generally, transfer residual toner recovered from the photoreceptor drum 5 tends to spill from both ends of the cleaning blade 47, and if it adheres to the photoreceptor drum 5 again and then adheres to the belt member 18, the charging roller 14 and The gap G between the photoreceptor drums 5 becomes larger.

However, as described above, if the cleaning width Wc is located inside the belt members 18 on both sides, the recovered toner and the like scattered from the cleaning blade 47 are less likely to adhere to the belt members 18, and the gap G can be prevented from becoming large.

Fig. 10 relates to the fourth embodiment of the present invention, and is a schematic diagram similar to Fig. 7 for comparing the width relationship of each part of the imaging system of the image forming apparatus according to the fourth embodiment of the present invention;

In the small printer as the image forming apparatus of this embodiment, as in the embodiment of FIG. 8 , the cleaning blade 47 is swung in a direction perpendicular to the sliding direction of the photoreceptor drum 5 by the cleaning member swing mechanism 70 , and the The cleaning swing area width Wsc of the cleaning blade 47 swinging by the cleaning member swing mechanism 70 is set as the cleaning width, which is located in the coating portion 61 of the photoreceptor drum 5 (at the portion of the coating width Wt) as shown in FIG. 10 , The left and right ends of the cleaning swing area width Wsc of the cleaning blade 47 are positioned inside the paired side belt members 18, 18 (disposed at the left and right belt width Wta positions in FIG. 10 ).

In this embodiment, the cleaning blade 47 is not in sliding contact with the coated portion 61, the non-coated portion 62, and the non-coated portion of the photoreceptor drum 5, so early wear of the cleaning blade 47 can be prevented.

The movement limit positions (the left end and the right end positions of the cleaning swing region width Wsc) of the cleaning blade 47 swinging by the cleaning member swing mechanism 70 are respectively located inside the belt members 18, 18 on both sides, therefore, the same as in the embodiment of FIG. 9 , the cleaning width Wc area of the coating portion 61 is gradually worn away by the cleaning blade 47, and the gap G between the charging roller 14 and the surface of the photoreceptor drum 5 illustrated in FIG. 1 gradually becomes larger.

Therefore, it is possible to determine that the life of the photoreceptor drum 5 has reached the end of its life by utilizing the time when the charging failure occurs as the gap G increases.

11 is a schematic diagram similar to FIG. 6 of an image forming apparatus in which the cleaning width of the cleaning member is located outside the outer edge edges of a pair of belt members, relating to a fifth embodiment of the present invention.

Compared with the small-sized printer of FIG. 6, the small-sized printer as an image forming apparatus of this embodiment is only different in that the cleaning width Wc is located outside the outer edges of the pair of belt members 18, 18, and the other configurations are the same. Therefore, each part The illustration of the configuration is omitted, and the symbols used in Fig. 1 to Fig. 6 are used for description as necessary.

In this way, if the outer edge of the pair of belt members 18, 18 is set as the cleaning width Wc, the same as the miniature printer in FIG. 4) Sliding connection, after a long period of operation, the area of the cleaning width Wc is worn away, and a pair of belt members 18 and 18 respectively arranged at the position of the belt width Wta shown in FIG. Make contact with the wearing part with a margin.

Therefore, the gap G between the effective charging width Wac of the charging roller 14 shown in FIG. 1 and the surface of the photoreceptor drum 5 is usually kept constant, so that a good image can be obtained even after a long period of operation.

12 is a schematic diagram similar to FIG. 7 of an image forming apparatus in which the cleaning width of the swing cleaning blade is located outside the outer edge edges of a pair of belt members, relating to a sixth embodiment of the present invention.

In the small printer as an image forming apparatus of this embodiment, as in the embodiment of FIG. 7, the cleaning blade 47 is swung in a direction perpendicular to the sliding direction of the photoreceptor drum 5 by the cleaning member swing mechanism 70, and the The cleaning swing area width Wsc of the cleaning blade 47 swinging by the cleaning member swing mechanism 70 is set as the cleaning width, and only when the cleaning width is located outside the pair of belt members 18, 18 (in FIG. The outer side of the end edge is different from the embodiment of FIG. 7 .

In this way, if the cleaning swing area width Wsc is set as the cleaning width, then, like the small printer in FIG. Afterwards, the cleaning width Wc area is worn away, and the pair of belt members 18, 18 can also contact the worn portion with a margin in the left-right direction shown in FIG. 11 .

Therefore, in this embodiment, the gap G between the effective charging width Wac portion of the charging roller 14 shown in FIG. good image.

Fig. 13 relates to the seventh embodiment of the present invention, and is a front view of the seventh embodiment in which the gap management member is a roller.

The gap management members of this embodiment are rollers 81, 81 mounted on both ends of the metal core 16 of the charging roller 14', respectively. The roller 81 can be formed of rubber, for example, so that the outer diameter D2 is larger than the outer diameter D1 of the conductive rubber roller portion 17' of the charging roller 14', and the gap G is formed by the difference between the outer diameter D2 and D1, for example, 100 μm or less. Clearance.

In the present embodiment, the pair of rollers 81 , 81 are in contact together with the non-charging area of the coated portion 61 which is softer than the non-coated portion 62 of the photoreceptor drum 5 . Therefore, even if the above-mentioned gap is set to be 100 μm or less, since the roller 81 is not easily worn, a certain gap amount can be maintained for a long period of time, and charging can be performed well over a long period of time.

In the various embodiments of the image forming apparatus of the present invention described above, it is preferable that both ends of the metal core 16 are disposed away from the non-coating portion 62, and that when a voltage is applied between the metal core 16 and the photoreceptor drum 5 It is a position where leakage does not occur from both ends of the metal core 16 to the non-coated portion 62 of the photoreceptor drum 5 .

As illustrated in FIG. 1 , this compact printer is provided with a pair of belt members 18 and 18 between the charging roller 14 and the photosensitive drum 5 . For the predetermined gap G, the size of the gap G is controlled, and when the axial flatness of the surface of the photoreceptor drum 5 is set to D, and the axial flatness of the surface of the conductive rubber roller portion 17 of the charging roller 14 is set to E, it satisfies The following relationship: D+E<G.

That is to say, there will be unavoidable micro-concavities and convexities on the surface of all parts during production. FIG. 14 is an enlarged view of an axial cross-sectional shape of the photosensitive drum 5. As shown in FIG. Take the axial flatness D (equal to H1) of the photosensitive drum 5; FIG. 15 is an explanatory diagram of the axial flatness of the surface of the conductive rubber roller portion of the charging roller. The height from the bottom 17a to the highest peak 17b on the surface of the conductive rubber roller portion 17 is H2, and the axial flatness E (equal to H2) of the charging roller 14 is obtained from the height H2. The above formula indicates that the gap G shown in FIG. 1 is greater than the sum of H1 and H2 above.

The gap G satisfying the relationship described above is determined by the thickness of the belt members 18 , 18 wound around the outer peripheral surfaces of both ends of the conductive rubber roller portion 17 of the charging roller 14 .

In this way, as shown in FIG. 15, assuming that the tip 5b of the photosensitive drum 5 faces the tip 17b of the conductive rubber roller portion 17 of the charging roller 14, even in that state, since the relational expression: D+E <G relationship, the peak portion 5b of the photoreceptor drum 5 and the peak portion 17b of the conductive rubber roller portion 17 of the charging roller 14 do not contact.

Therefore, according to this image forming apparatus, even if an attached matter such as transfer residual toner adheres to the surface of the photosensitive drum 5, since the surface of the photosensitive drum 5 is not in contact with the charging roller 14, the attached matter does not transfer to the charging roller. 14 surfaces. Therefore, it has good charging performance, and high-quality images can be obtained.

If the gap G is too large, charging performance will be lowered, and it is preferably 100 μm or less, for example.

In addition, if the maximum straightness of the axial straightness in several different positions in the circumferential direction of the photoreceptor drum 5 is set as D, the conductive rubber roller portion 17 of the charging roller 14 has the axial straightness in several different positions in the circumferential direction of the surface. Among the flatnesses, the maximum flatness is E, and the contact probability between the tip 5b of the photoreceptor drum 5 and the tip 17b of the conductive rubber roller portion 17 of the charging roller 14 is almost zero over the entire circumference.

However, even if the flatness D is determined only by the flatness of one axial direction of the surface of the photosensitive drum 5, and the flatness E is determined only by the flatness of one axial direction of the surface of the conductive rubber roller portion 17 of the charging roller 14, since their The flatness is generally not much different from the flatness of other positions in the circumferential direction, and it will not be a problem.

Assuming that in this state, the tip 5b of the photoreceptor drum 5 contacts the tip 17b of the conductive rubber roller portion 17 of the charging roller 14 for an instant at a certain moment, even then, because it is not always in contact, it will not become what is the problem.

17 relates to an eighth embodiment of the present invention, and is a schematic configuration diagram of the vicinity of an imaging section of an image forming apparatus in which the image carrier is a belt-shaped photoreceptor belt.

The image forming unit of the image forming apparatus of this embodiment is provided with a belt-shaped photoreceptor belt 75 as an image carrier, which is stretched over several rollers and rotates in the direction of arrow K in the figure.

The belt surface of the photoreceptor belt 75 is charged by the charging roller 14 as a charging device, and the above-mentioned charging surface is exposed through an optical system 81 composed of a light source, an illumination mirror, a projection lens, and a projection mirror, and a latent surface is formed there. picture.

When the photoreceptor belt 75 turns in the direction of the arrow K, when the latent image moves to the position of the developing device 72, the developing device 72 develops it into a visible image (ink image).

The visible image is transferred onto the transfer paper P by the transfer unit 73, heated and fixed by the fixing device 74, and discharged to a paper discharge tray or the like not shown.

The transfer residual toner remaining on the surface of the photoreceptor belt 75 is cleaned by the cleaning device 76, and the subsequent image forming operations are repeated.

Also in this image forming apparatus, the belt members 18, 18 wound and fixed at both ends of the conductive rubber roller portion 17 are brought into contact with the image forming area portion on the surface of the photoreceptor belt 75 as an image carrier (see FIG. 1 ). In the image forming area Wac) to be described, a predetermined gap G corresponding to the thickness of the belt member is formed in the image forming area.

Also, when the flatness of the surface of the photoreceptor belt 75 is A, the flatness of the surface of the charging roller 14 facing the photoreceptor belt 75 (when the charging member has a flat surface such as a plate shape is called flatness) When it is set to B, the following relationship is satisfied: A+B<G.

That is, the surface flatness B of the photoreceptor belt 75 is obtained from the height from the bottom of the microconcaves and convexes formed on the surface of the photoreceptor belt 75 to the top of the highest point, so that the surface flatness B of the conductive rubber roller portion 17 formed on the charging roller 14 Find the straightness (or flatness) A of the charging roller 14 from the bottom of the top to the highest point, so that the gap G shown in FIG. 17 is greater than the sum of A and B above.

In this way, the tip of the above-mentioned photoreceptor belt 75 does not come into contact with the tip of the conductive rubber roller portion 17 of the charging roller 14. Therefore, as in the case of the above-mentioned image forming apparatus using a photoreceptor drum, residues on the photoreceptor belt can be prevented. Attachments such as transfer residual toner on the surface of 75 are transferred to the charging roller 14 .

In the embodiment shown in FIG. 13, the gap G is made larger than the sum of the axial flatness D of the surface of the photosensitive drum 5 and the axial flatness E of the surface of the conductive rubber roller portion 17' of the charging roller 14'.

In this way, the conductive rubber roller portion 17' of the charging roller 14' does not come into contact with the image forming area Wac portion on the surface of the photoreceptor drum. Transferred to the surface of the charging roller 14', good charging performance can be obtained, and high-quality images can be obtained.

Next, production examples of the photoreceptor of the image forming apparatus of the present invention will be described, but are not limited to these production examples.

Photoreceptor production example 1:

On a Φ30mm aluminum cylinder, the coating solution for the undercoat layer, the coating solution for the charge generation layer, the coating solution for the charge transport, and the coating solution for the protective layer of the following composition are sequentially coated and dried to obtain a 3.5 μm undercoat layer , a charge generation layer of 0.2 μm, a charge transport layer of 20 μm, and a protective layer of 5 μm were formed in a laminated state to obtain each photoreceptor in the image forming apparatus of the present invention. The primer layer, charge generation layer and charge transport layer are formed by dip coating, and the protective layer is formed by spray coating.

[Coating solution for undercoating]

Alkyd resin

(Alkyd resin 1307-60-EL, manufactured by Dainippon Ink Science Co., Ltd.) 6 parts by weight

Melamine resin

(Super synthetic urea resin G-821-60, manufactured by Dainippon Ink Science Co., Ltd.) 4 parts by weight

Titanium oxide (CR-EL, manufactured by Ishihara Sangyo Co., Ltd.) 40 parts by weight

Methyl-ethyl ketone 200 parts by weight

[Coating solution for charge generation layer]

3 parts by weight of the charge generating substance of the following chemical formula 1 structure

chemical formula 1

polyvinyl acetal

(ェスレックBX-1, manufactured by Sekisui Chemical Co., Ltd.) 1 part by weight

Methyl-ethyl ketone 100 parts by weight

[Coating solution for charge transport]

Z type polycarbonate

(Polycarbonate resin TS-2050, manufactured by Teijin Chemical Industry Co., Ltd.) 1 part by weight

8 parts by weight of the low-molecular charge transport substance of the following chemical formula 2 structure

chemical formula 2

Tetrahydrofuran 100 parts by weight

Silicone oil (KF50-100CS, manufactured by Shin-Etsu Chemical Co., Ltd.) 1 part by weight

[Coating solution for protective layer]

Z type polycarbonate

(Polycarbonate resin TS-2050, manufactured by Teijin Chemical Industry Co., Ltd.) 10 parts by weight

7 parts by weight of the low-molecular charge transport substance of the following chemical formula 3 structure

chemical formula 3

Tetrahydrofuran 100 parts by weight

Cyclohexanone 400 parts by weight

α-alumina

(Sumikolandam AA-03, manufactured by Sumitomo Chemical Industry Co., Ltd.) 5 parts by weight

Low intrinsic resistance material (BYK-P104, manufactured by Bicchem Corporation) 0.05 parts by weight

Photoreceptor production example 2:

Photoreceptor Production Example 2 is the same as Photoreceptor Production Example 1 except that the protective layer coating solution in Photoreceptor Production Example 1 above was changed. Titania is used in this example instead of alpha-alumina.

[Coating solution for protective layer]

Z type polycarbonate

(Polycarbonate resin TS-2050, manufactured by Teijin Chemical Industry Co., Ltd.) 10 parts by weight

7 parts by weight of the low-molecular charge transport substance of the following chemical formula 4 structure

chemical formula 4

Tetrahydrofuran 100 parts by weight

Cyclohexanone 400 parts by weight

Titanium oxide (manufactured by Ishihara Sangyo Co., Ltd.) 5 parts by weight

Low intrinsic resistance material (BYK-P104, manufactured by Bitsukuchemi Co., Ltd.) 0.05 parts by weight

Photoreceptor production example 3:

Photoreceptor Production Example 3 is the same as Photoreceptor Production Example 1 except that the protective layer coating solution in Photoreceptor Production Example 1 above was changed. In this example the alpha-alumina is replaced by silica.

[Coating solution for protective layer]

Z type polycarbonate

(Polycarbonate resin TS-2050, manufactured by Teijin Chemical Industry Co., Ltd.) 10 parts by weight

7 parts by weight of the low-molecular charge transport substance of the following chemical formula 5 structure

chemical formula 5

Tetrahydrofuran 100 parts by weight

Cyclohexanone 400 parts by weight

Silica (manufactured by Shin-Etsu Silicon Co., Ltd.) 5 parts by weight

Low intrinsic resistance material (BYK-P104, manufactured by Bitsukuchemi Co., Ltd.) 0.05 parts by weight

Photoreceptor production example 4:

Photoreceptor Production Example 4 is the same as Photoreceptor Production Example 1 except that the protective layer coating solution in Photoreceptor Production Example 1 above was changed. In this example, instead of using Z-type polycarbonate, a high-molecular charge-transporting substance was used instead of a low-molecular charge-transporting substance, and silica was used instead of α-alumina.

[Coating solution for protective layer]

18 parts by weight of the polymer charge transport material of the following chemical formula 6 structure

chemical formula 6

Tetrahydrofuran 100 parts by weight

Cyclohexanone 400 parts by weight

Silicon dioxide (manufactured by Shin-Etsu Silicon Co., Ltd.) 5 parts by weight

Low intrinsic resistance material (BYK-P104, manufactured by Bicchem Corporation) 0.05 parts by weight

Photoreceptor production example 5:

In photoreceptor preparation example 5, the film thickness of the charge transport layer in photoreceptor preparation example 1 was set to 25 μm, and no protective layer was provided. Others were the same as photoreceptor preparation example 1.

The material of the belt parts will be described below.

Polyethylene terephthalate, polypropylene, and polyimide can be used, and polypropylene is used in the above embodiment. The thickness of the polypropylene layer of the tape member is 40 μm, the adhesive layer is 20 μm, and the total thickness is 60 μm.

For the case where the belt part is in contact with the coated part and the case where the non-coated part is in contact, the continuous paper passing test is carried out to observe the wear condition of the belt, such as damage and curl of the belt. Each was carried out three times, and the test results are shown in the table below. Painting Department Non-painting department First time Round two third time First time Round two third time early stage ◎ ◎ ◎ ◎ ◎ ◎ 10K ○ ○ ○ ○ ○ ○ 20K ○ ○ ○ ○ ▲ ○ 50K ○ ○ ○ △ x △ 100K ○ ○ ○ △ - △

Meanings of symbols in the table:

◎ No damage.

○ Slight scratches on the surface, but no problem.

△ The belt is damaged, and the incision is raised due to the entry of foreign matter.

▲ With end stripping.

× Tape completely peeled off.

K 1000(pieces)

It can be seen from the above table that in the initial stage and 10K period, whether the belt part is in contact with the painted part or the non-painted part is in contact, it is in good condition, but after 20K, the belt part is in contact with the painted part The occasion is obviously better than the occasion where it is in contact with the non-painted part.

Certainly, the present invention is not limited to the above-mentioned embodiments, and various changes can be made within the scope of the technical thought of the present invention, and they all belong to the protection scope of the present invention.

Claims (22)

1. image processing system, be provided with picture mounting body and Charging system, above-mentionedly comprise the finish department that forms photographic layer and be formed on the non-finish department of its both sides that as the mounting body above-mentioned Charging system comprises makes this as the charged live part of the finish department of mounting body with the material harder than this finish department; It is characterized in that, gap management component contacts with the non-charging zone of the finish department of above-mentioned picture mounting body, above-mentioned live part is contacted with above-mentioned picture mounting surface by gap management component, in the effective charged width segments of above-mentioned Charging system, between above-mentioned live part and picture mounting body, form institute's fixed gap.

2. according to the image processing system described in the claim 1, it is characterized in that, be provided with cleaning device, by slipping with above-mentioned finish department as the mounting body, clean with clean surely width, make above-mentioned gap management component be positioned at the cleaning width of this cleaning device.

3. according to the image processing system described in the claim 2, it is characterized in that above-mentioned cleaning width is up to the outside of above-mentioned gap management component outside ora terminalis.

4. according to the image processing system described in the claim 1, it is characterized in that, be provided with cleaning device, by slipping with above-mentioned finish department as the mounting body, clean with clean surely width, make the cleaning width of above-mentioned cleaning device be positioned at the inboard of above-mentioned gap management component.

5. according to any described image processing system among the claim 2-4, it is characterized in that, be provided with the cleaning member tilting mechanism, make the cleaning member of above-mentioned cleaning device towards the relative direction swing of slipping the direction orthogonal as the mounting body with this cleaning member, the cleaning wobble area width of above-mentioned cleaning member that will be by this cleaning member tilting mechanism swing is made as above-mentioned cleaning width.

6. according to any described image processing system among the claim 2-4, it is characterized in that above-mentioned cleaning device is the means that make cleaning balde and above-mentioned finish department as the mounting body slip this finish department of cleaning.

7. according to any described image processing system among the claim 1-4, it is characterized in that, be provided with transfer member, but with the video transfer printing that is formed on above-mentioned picture mounting surface on the transfer printing material, make that effective transfer printing width of this transfer member is shorter than the effective charged width of above-mentioned Charging system.

8. according to any described image processing system among the claim 1-4, it is characterized in that, be provided with developing apparatus, but become video with above-mentioned as image development on the mounting body, make that the development width of this developing apparatus is shorter than the effective charged width of above-mentioned Charging system by developer.

9. according to the image processing system described in the claim 7, it is characterized in that, be provided with developing apparatus, but become video with above-mentioned as image development on the mounting body, make that the development width of this developing apparatus is shorter than effective transfer printing width by developer.

10. the image processing system described in according to Claim 8 is characterized in that above-mentioned developer is to use the double component developing of ink powder and carrier.

11. the image processing system according to described in the claim 2 is characterized in that, above-mentioned cleaning width is longer than effective charged width.

12. according to the image processing system described in the claim 2, it is characterized in that, be provided with the cleaning member tilting mechanism, make the cleaning member of above-mentioned cleaning device towards the relative direction swing of slipping the direction orthogonal as the mounting body with this cleaning member, the moving limit position of the above-mentioned cleaning member both sides by this cleaning member tilting mechanism swing lays respectively at the outside of above-mentioned effective charged width.

13. according to any described image processing system among the claim 1-4, it is characterized in that, above-mentioned live part is the charged roller that forms elastic in the part at the both ends of removing the metal shaft outer peripheral face, above-mentioned gap management component is a pair of tape member that is separately fixed at the both ends of above-mentioned elastic, and the width between the inboard of above-mentioned a pair of tape member becomes above-mentioned effective charged width.

14. the image processing system according to described in the claim 13 is characterized in that, above-mentioned tape member thickness is below the 100 μ m.

15. according to the image processing system described in the claim 13, it is characterized in that, above-mentioned a pair of tape member is fixed on the both ends of above-mentioned elastic along circumferentially reeling respectively, and circumferentially two ends are not overlapping mutually, do not have the part that has not a particle of tape member in whole positions in a week.

16. the image processing system according to described in the claim 15 is characterized in that, the circumferential two ends of above-mentioned a pair of tape member are cut into oblique respectively, make the mutual subtend of otch ora terminalis, form the gap between the ora terminalis at these otch two ends.

17. the image processing system according to described in the claim 16 is characterized in that, is cut into oblique part at the circumferential two ends of above-mentioned a pair of tape member, the angle of inclination of the lateral margin of the relative tape member of line of cutting sth. askew is roughly 45 degree.

18. according to the image processing system described in the claim 13, it is characterized in that, above-mentioned charged roller is configured to make the metal shaft both ends to leave non-finish department, be configured in when metal shaft and when applying voltage between as the mounting body from these metal shaft both ends to the position that the non-finish department as the mounting body does not leak.

19. according to the image processing system described in the claim 1, it is characterized in that, above-mentioned live part is the charged roller that forms elastic in the part at the both ends of removing the metal shaft outer peripheral face, and above-mentioned gap management component is the roller at both ends that is installed in the metal shaft of above-mentioned charged roller respectively.

20. an image processing system, be provided with comprise photographic layer as the mounting body and comprise the Charging system of live part, above-mentioned live part makes above-mentioned picture mounting body charged; It is characterized in that:

Gap management component contacts with the non-charging zone of above-mentioned picture mounting body, and above-mentioned live part is contacted with above-mentioned picture mounting surface by gap management component, forms institute's fixed gap between above-mentioned live part and picture mounting body;

Cleaning device is set,, cleans with clean surely width by slipping as the mounting body with above-mentioned;

Above-mentioned gap management component is positioned at the cleaning width of this cleaning device.

21. picture carrier assembly, be provided with picture mounting body and Charging system, above-mentionedly comprise the finish department that forms photographic layer and be formed on the non-finish department of its both sides that as the mounting body above-mentioned Charging system comprises makes this as the charged live part of the finish department of mounting body with the material harder than this finish department; It is characterized in that, gap management component contacts with the non-charging zone of the finish department of above-mentioned picture mounting body, above-mentioned live part is contacted with above-mentioned picture mounting surface by gap management component, in the effective charged width segments of above-mentioned Charging system, between above-mentioned live part and picture mounting body, form institute's fixed gap; Above-mentionedly be made as one as mounting body and live part.

22. a picture carrier assembly, be provided with comprise photographic layer as the mounting body and comprise the Charging system of live part, above-mentioned live part makes above-mentioned picture mounting body charged; It is characterized in that: gap management component contacts with the non-charging zone of above-mentioned picture mounting body, and above-mentioned live part is contacted with above-mentioned picture mounting surface by gap management component, forms institute's fixed gap between above-mentioned live part and picture mounting body; Cleaning device is set,, cleans with clean surely width by slipping as the mounting body with above-mentioned; Above-mentioned gap management component is positioned at the cleaning width of this cleaning device; Above-mentionedly be made as one as mounting body and live part.

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