JP3576894B2 - Sheet member conveying device in image forming apparatus - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a sheet member transport device in an image forming apparatus such as a copying machine, a facsimile, a printer, or the like, which transports a sheet member to an image forming unit in order to form image information such as a document on a sheet member. is there.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in a sheet member conveying device that conveys a sheet member to an image forming unit in order to form image information such as a document on a sheet member, one is a driving roller and the other is pressed against and driven by the driving roller. It is widely and generally adopted that the sheet member is conveyed while being sandwiched between the pair of upper and lower rollers.
[0003]
1 and 2 show a conventional conveying roller pair, which will be described below with reference to FIGS.
[0004]
Conventionally, the conveying roller pair 300 is composed of rollers 302 and 306 fixed to shafts 304 and 308, and the paper dust removing roller formed by the shaft 312 and the roller 310 is brought into contact with one of the rollers of the roller pair. Are placed. In general, the width of the rollers 302 and 306 is set to be longer than the maximum width of the sheet member P in the width direction. The width of the roller 310 of the paper dust removing roller is the same as the width of one of the rollers 302 and 306 of the roller pair.
[0005]
However, since the entire area of the sheet member P is sandwiched between the roller pairs, the sheet member P may be different depending on the type of the sheet member P (a sheet member containing a large amount of water) and the atmosphere environment (when the humidity is high such as during the rainy season). There have been problems such as wrinkles in the member P, image formation cannot be performed, or appropriate image formation cannot be performed.
[0006]
As shown in FIG. 2, the conveying roller pair 400 is composed of rollers 402 and 406 fixed to shafts 404 and 408, and a paper dust removing roller formed by a shaft 412 and a roller 410 is used as one of the rollers of the roller pair. Are placed in contact with The width of the roller 406 is longer than the width of the largest sheet member P in the width direction, and the width of the paper dust removing roller 410 is also equal to or greater than the width of the roller 406. Then, in order to solve the problem of wrinkles generated in the conveying roller pair 300 illustrated in FIG. 1, the width direction length of the upper roller 402 of the conveying roller pair 400 is set to be short, and the entire width of the sheet member P is pinched. There has been proposed a configuration in which the sheet is conveyed without being used. According to such a configuration, the problem of wrinkles can be substantially solved. However, since the sheet member P is conveyed without pinching the entire area in the width direction, the edge portion of the sheet member P is mainly Since the generated paper dust cannot be sufficiently removed, the sheet member P is conveyed to an image forming area which is a downstream process. In the image forming area, various devices around the photoreceptor for image formation, for example, a charging device, an exposure device, a developing device, a transfer device, a cleaning device, and the like, and when paper dust enters the device, Affects the image. More specifically, if paper dust is mixed into the developing device, the developer agglomerates or uneven development occurs. When paper dust enters the cleaning blade or brush of the cleaning device, cleaning failure occurs. When paper dust adheres to the charging wires of the charging device and the transfer device, the adhering portion becomes poorly charged, and leakage or poor charging makes it impossible to form a good image and causes poor transfer.
[0007]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION It is an object of the present invention to convey a sheet member without generating wrinkles, and to completely remove paper dust, and as a result, perform stable and good image formation on a sheet member over a long period of time. It is an object of the present invention to provide a sheet member conveying device of an image forming apparatus capable of performing the above.
[0008]
[Means for Solving the Problems]
According to the present invention, there is provided a sheet member conveying device in an image forming apparatus, wherein a first roller having a conveying width equal to or larger than a width of a sheet member to be used, and a width of the first roller above the first roller relative to the first roller . A second roller that comes into contact in part of the direction and conveys the sheet member in cooperation with the first roller, a shaft that fixedly supports the second roller, and is loosely fitted to the shaft at a side of the second roller; and a tubular third roller, the third roller is provided a sheet conveying device in the image forming apparatus characterized by contacting the first roller at a portion excluding the front Symbol part (claim 1 ). According to this configuration, the first roller and the second roller cooperate to pinch and convey a part of the sheet member, and do not pinch and convey the entire area of the sheet member. Is conveyed without generating any. Since the third roller is loosely inserted into the shaft and held to the side of the second roller and extends to a region equal to or larger than the width of the sheet member, the edges at both ends in the width direction of the sheet member to be used are the first roller and the third roller. Since the paper is conveyed in contact with the third roller or the second roller, the paper dust is removed through the contacted roller.
[0009]
Further, the distance between the shaft supporting the first roller and the shaft supporting the second roller is fixed, and the outer diameter of the second roller is equal to the outer diameter of the third roller. is set, the outer diameter of the shaft L1, the inner diameter of the third roller L2, when the thickness of the sheet member and [Delta] P, the sheet conveying device is provided in the L2> the image forming apparatus is L1 + 2 [Delta] P (claim 2). According to this configuration, outside the width direction of the second roller, the sheet member, particularly the edge portion, is in contact with the first roller and the third roller but is not pinched, so that the sheet member does not wrinkle. Then, the paper dust is removed, and the paper is nipped and transported by the first roller and the second roller.
[0010]
Further, there is provided a sheet member conveying device in the image forming apparatus in which the third roller is held on the shaft on both sides of the second roller (claim 3). According to this configuration, the first roller and the second roller cooperate to pinch and convey the central portion of the sheet member. On both sides in the width direction of the second roller, the sheet members, particularly the side edges, contact the first roller and the third roller but are not pinched, so that the sheet member does not wrinkle and Is removed and transported.
[0011]
Further, the sheet member conveying apparatus is provided in an image forming apparatus having a first roller surface and in contact with the paper dust removing member (claim 4). According to this configuration, the sheet member is conveyed by being pinched or contacted by the first roller and the second roller or the third roller, or conveyed by being pinched or contacted by the first roller and the second roller or the fourth roller. Thus, the paper dust of the sheet member is removed by a paper dust removing member that contacts the surface of the first roller.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 3 is a diagram illustrating an image forming apparatus according to the present invention. Hereinafter, the image forming process will be described with reference to FIG.
[0013]
In the image forming apparatus 2, a photosensitive drum 4 having a surface coated with a photoconductive layer is rotatably arranged in a direction indicated by an arrow X at a required position of the main body. A scorotron charging device 6 for uniformly charging the surface of the photosensitive drum 4 is disposed on the peripheral surface of the photosensitive drum 4, and the charged photosensitive drum 4 transmits information (signal) such as an image at an exposure position. Exposure is performed by a light emitting element 8 such as a laser to form an electrostatic latent image. Thereafter, the electrostatic latent image is developed (developed) into a toner image by the developing device 10. Next, the toner image on the photosensitive drum 4 is transferred by the transfer charging device 12 onto the sheet member P which is fed out from the sheet feeding cassette 14 by the sheet feeding roller 16 and conveyed through the registration roller pair 18.
[0014]
One end of the sheet member P is stopped just before the nip point of the registration roller pair 18, and the timing is adjusted so that the front end of the toner image on the surface of the photosensitive drum 4 and the front end of the sheet member P coincide. To re-drive. The sheet member P having the toner image transferred onto the surface thereof is separated from the photosensitive drum 4 by the peeling device 20, further conveyed downstream, and the transferred image is fixed on the surface of the sheet member P by the fixing device 22 and discharged out of the machine. You.
[0015]
After the sheet member P is peeled from the photoconductor 4 by the peeling device 20, the photoconductor 4 further continues to rotate, and the cleaning device 24 collects the toner remaining on the surface of the photoconductor drum 4 and is constituted by a discharging lamp. The residual charge remaining on the surface of the photoconductor 4 is removed by the charge removing device 26 to prepare for the next image forming step.
[0016]
FIG. 4 is a side view showing details of a pair of registration rollers as a transfer device, and FIG. 5 is a sectional view taken along line AA showing details of the pair of registration rollers as a transfer device. The following description will be made with reference to FIGS. I do.
[0017]
The lower roller of the registration roller pair 18 includes a shaft 184 serving as a rotation shaft and a first roller 185 formed of a resin material such as POM (polyacetal) fixed to the shaft 184 and disposed in the entire width direction. It is configured. Further, a paper dust removing roller composed of a shaft 186 and a paper dust removing member 187 is provided in pressure contact with the first roller 185.
[0018]
In the present embodiment, the upper roller of the registration roller pair 18 has a shaft 181 serving as a rotation shaft, and a second roller formed of synthetic rubber such as chloroprene rubber fixed to the shaft 181 and arranged at the center in the width direction. The roller 182 includes a third roller 183 that is loosely inserted into the shaft 181 on both sides of the second roller 182.
[0019]
The third roller 183 is configured not to move in the width direction with respect to the shaft 181 using, for example, an E-shaped retaining ring (not shown).
[0020]
The outer diameter L1 of the shaft 181 is set to L1 = 6 mm, and the inner diameter L2 of the third roller 183 is set to L2 = about 6.1 mm to 6.4 mm.
[0021]
The width of the first roller 185 is, for example, about 20 mm longer than the width of the JIS A4 size, specifically, 320 mm. The width of the paper dust removing member 187 is longer than the width of the first roller by 10 mm, specifically, 330 mm. Further, the total width of the two third rollers 183 on both sides of the second roller and the second roller 182 is the same as the width of the first roller 185 and is 320 mm.
[0022]
Therefore, as shown in FIGS. 4 and 5, when the sheet member P is not being conveyed, the third roller 183 is in contact with the first roller 185, and the third roller 183 is floating with respect to the shaft 181. It has become.
[0023]
Next, FIG. 6 is a cross-sectional view showing the details of a registration roller as a transport device similarly to FIG. 5, and shows a state in which the sheet member P is being transported. Hereinafter, description will be made also with reference to FIG.
[0024]
When the state changes from the state of FIG. 5 to a state in which the sheet member P is nipped and conveyed by the second roller 182 and the first roller 185 (see FIG. 6), the third roller 183 comes into contact with the first roller 185 and is driven. The state (see FIG. 5) changes from a state of being in contact with the sheet member P (see FIG. 6) to a state in which the sheet member P is driven. More specifically, even when the third roller 183 is in contact with the sheet member P, the third roller 183 does not actively pinch and convey the sheet member P together with the first roller 185, and the sheet member P is This is a state in which the sheet is conveyed while being pinched and transported by the first roller 185.
[0025]
For this reason, when the sheet member P is conveyed by the registration roller pair 18, the entire area in the width direction is in contact with the first roller 185, the second roller 182, and the third roller 183, even for the maximum sheet P. In particular, paper dust generated at edges at both ends in the width direction of the sheet member P mainly adheres to the surface of the first roller 185 and the surface of the third roller 183 and a part thereof to the surface of the second roller 182. After passing through the pair of registration rollers 18, paper dust adhering to the surface of the third roller 183 or the second roller 182 moves to the first roller 185, and is thereafter removed and collected by the paper dust removal roller 187. In addition, since the paper dust removing roller 187 removes and collects the paper dust as the sheet member P passes, it is necessary to periodically perform maintenance such as cleaning or replacing with a new one in order to maintain long-term high image quality of the image forming apparatus. It is valid.
[0026]
Next, another embodiment of the present invention will be described.
[0027]
FIG. 7 is a side view showing details of a registration roller as a transfer device for explaining another embodiment of the present invention, and FIG. 8 is a view showing details of a registration roller as a transfer device for explaining another embodiment of the present invention. FIG. 9 is a cross-sectional view taken along the line B-B, which will be described below with reference to FIGS. 7 and 8. The same members have the same names and the same numbers as those in the above-described embodiment for clarity in the description.
[0028]
In the present embodiment, the upper roller of the registration roller pair 18 has a shaft 181 serving as a rotation shaft and a second roller formed of a synthetic rubber such as chloroprene rubber fixed to the shaft 181 and arranged at the center in the width direction. The roller 182 includes a fourth roller 283 fixed to the shaft 181 on both sides of the second roller 182. The lower roller of the registration roller pair 18 includes a shaft 184 serving as a rotation shaft and a lower roller 185 fixed to the shaft 184 and disposed over the entire area in the width direction and formed of a resin material such as POM (polyacetal). Have been. Further, a paper dust removing roller composed of a shaft 186 and a paper dust removing member 187 is provided in pressure contact with the first roller 185.
[0029]
The outer diameter L3 of the second roller 182 is set to L3 = 13.0 mm to 13.8 mm, and the outer diameter L4 of the fourth roller 283 is set to L4 = 12.7 mm to 12.9 mm. Therefore, as shown in FIG. 8, the gap ΔL2 is configured to be about 0.05 mm to 0.55 mm. By the way, if the gap ΔL2 is about 0.75 mm, depending on the paper quality, even if both edges in the width direction are warped upward, the paper cannot be sufficiently contacted with the outer diameter of the fourth roller 283 and paper dust can be collected. Was not enough. If the gap ΔL2 is about 1.0 mm, the paper dust is not sufficiently collected, and the paper dust adheres to the charging device, the charging wire of the transfer device, and the housing of the wire, causing a leak to occur. It was possible. Therefore, in the present embodiment, the gap ΔL2 is set to be about 0.05 mm to 0.55 mm so that the paper dust is sufficiently collected and the adverse effect on the image is eliminated.
[0030]
The width of the first roller 185 is about 20 mm longer than the width of the JIS A4 size, specifically, 320 mm. The width of the paper dust removing member 187 is longer than the width of the first roller by 10 mm, specifically, 330 mm. Further, the total width of the two fourth rollers 283 on both sides of the second roller and the second roller 182 is equal to the width of the first roller 185 and is 320 mm.
[0031]
Therefore, as shown in FIGS. 7 and 8, when the sheet member P is not being conveyed, the fourth roller 283 is in a state of not contacting the first roller 185.
[0032]
Next, FIG. 9 is a cross-sectional view showing the details of a pair of registration rollers as a conveying device, similarly to FIG. 8, and shows a state in which the sheet member P is being conveyed. Hereinafter, description will be made with reference to FIG.
[0033]
When the state changes from the state in FIG. 8 to a state in which the sheet member P is nipped and conveyed by the second roller 182 and the first roller 185 (see FIG. 9), the fourth roller 283 is not in contact with the first roller 185. The state changes from (see FIG. 8) to at least the edges of both ends of the sheet member P (see FIG. 6). Even when the fourth roller 283 is in contact with both edges of the sheet member P, the fourth roller 283 does not actively pinch and convey the sheet member P together with the first roller 185, and the fourth roller 283 is located at the center in the width direction of the sheet member P. When the sheet member P is nipped and conveyed by the second roller 182 and the first roller 185, both edge portions in the width direction of the sheet member P warp up and come into contact with the surface of the fourth roller 283.
[0034]
For this reason, when the sheet member P is conveyed by the registration roller pair 18, the entire region in the width direction comes into contact with the first roller 185, the second roller 182, and the fourth roller 283. When the generated paper dust adheres to the surface of the first roller 185, the second roller 182, or the fourth roller 283, and then the sheet member P passes through the registration roller pair 18, the surface of the fourth roller 283 or the second roller 182 is formed. The paper dust adhered to the first roller 185 falls by the rotation of the fourth roller 283 and the second roller 182 or by gravity and moves to the first roller 185, and thereafter is removed and collected by the paper dust removing roller 187. In addition, since the paper dust removing roller 187 removes and collects the paper dust as the sheet member P passes, it is necessary to periodically perform maintenance such as cleaning or replacing with a new one in order to maintain long-term high image quality of the image forming apparatus. It is valid.
[0035]
Although the two embodiments are applied to a pair of conveying rollers upstream of an image forming area where an image is formed on a sheet member, the occurrence of paper dust is particularly prevented from being adversely affected on the image forming area. Further, it is possible to prevent the generation of paper dust without generating wrinkles in the sheet member, and it is possible to obtain a sufficient effect even when the method is performed on the downstream side of the image forming area.
[0036]
In the above-described embodiment, the registration roller pair has been described as an example of the sheet member conveyance device. However, a conveyance roller pair including a pair of roller pairs may be used, and the invention is not limited to the registration roller pair.
[0037]
In the above-described embodiment, the paper dust removing roller is illustrated in order to remove and collect the paper dust generated by the passage of the sheet member P. However, the paper dust removing brush such as the paper dust removing brush is provided on at least one entire width direction of the conveying roller pair. It is also possible to arrange a removing member.
[0038]
In the above-described embodiment, a method in which the so-called center reference method is adopted as the conveyance method and the conveyance is performed with the center of the sheet member aligned with the center of the conveyance roller pair. That is, the third roller or the fourth roller is disposed on both sides of the second roller disposed at the center in the width direction. However, as one side (one end) reference system, one end side of the conveying roller pair regardless of the size of the sheet member. It is also possible to adopt a method in which the sheet is conveyed in accordance with the standard. In this case, the second roller can be arranged at one end, and the third roller or the fourth roller can be arranged only at the other end of the second roller.
[0039]
In the above-described embodiment, the third roller or the fourth roller is disposed on each side of the second roller disposed at the center in the width direction. It is also possible to dispose a third roller or a fourth roller.
[0040]
【The invention's effect】
As described above in detail, according to the present invention, a part of the width of the sheet member is nipped and conveyed by the pair of rollers, and the third roller or the fourth roller comes into contact with both edges in the width direction of the sheet member. The sheet member is conveyed without causing wrinkles in the sheet member, and the paper dust can be completely removed. As a result, a good image can be formed stably over a long period of time. Can be performed on members.
[Brief description of the drawings]
FIG. 1 is a diagram of a transport device in a conventional image forming apparatus.
FIG. 2 is a diagram of a transport device in a conventional image forming apparatus.
FIG. 3 is a diagram illustrating an image forming apparatus according to the present invention.
FIG. 4 is a side view showing details of a pair of registration rollers as a transport device.
FIG. 5 is a sectional view taken along line AA of FIG. 4, showing details of a pair of registration rollers as a transport device.
FIG. 6 is a diagram illustrating a state where a sheet member P is being conveyed by a pair of registration rollers.
FIG. 7 is a side view showing details of a pair of registration rollers as a transport device according to another embodiment of the present invention.
FIG. 8 is a cross-sectional view taken along the line BB of FIG. 7, showing details of a pair of registration rollers as a transport device according to another embodiment of the present invention.
FIG. 9 is a diagram illustrating a state in which a sheet member P is being conveyed as a conveying device according to another embodiment of the present invention.
[Explanation of symbols]
2 ... image forming apparatus 18 ... registration roller pair (sheet member conveying device)
181, a shaft 182, a second roller 183, a third roller 185, a first roller
187 … Paper dust removing roller (Paper dust removing member)
283: fourth roller P: sheet member L1: outer diameter L2 of shaft: inner diameter L3 of third roller L: outer diameter L4 of second roller: outer diameter ΔP of third roller: thickness of sheet member

Claims (4)

A sheet conveying device in the image forming apparatus,
A first roller having a width or more transfer width of the sheet member to be used, the first roller cooperates with the sheet member contact the upper side of the first roller with respect to the first roller part in the width direction a second roller for conveying, comprising: a shaft fixedly supporting the second roller and a third roller at a side cylindrical loosely fitting the shaft of the second roller, the third roller before Symbol A sheet member conveying device in an image forming apparatus, wherein the sheet member is in contact with a first roller at a part except a part. The distance between the shaft supporting the first roller and the shaft supporting the second roller is fixed, and the outer diameter of the second roller and the outer diameter of the third roller are set equal. , the outer diameter of the shaft L1, the inner diameter of the third roller L2, the thickness of the sheet member and the [Delta] P, L2> sheet member conveying the image forming apparatus according to claim 1, characterized in that the L1 + 2 [Delta] P apparatus. 3. The sheet conveying device according to claim 1, wherein the third roller is held on the shaft on both sides of the second roller. 4. The sheet conveying device of the image forming apparatus according to any one of 3 claims 1 and having a first roller surface and in contact with the paper dust removing member.

Images