JP7017068B2 - Transport guide structure and image forming device - Google Patents

Description

The present invention relates to a transport guide structure and an image forming apparatus.

Conventionally, an image forming apparatus having a transport guide structure for guiding a recording material (paper) moving from a transfer device to a fuser has been known.

The recording material to which the image is transferred by the transfer device is in a state where the image is attached due to the charged charge, and the transfer guide structure is charged by repeatedly rubbing the recording material from the transfer device to the fuser with the transfer guide structure. There was a case that I did. Such charge charges in the transport guide structure may disturb the image on the recording material.

For example, Patent Document 1 discloses a sheet material guiding device in which a sheet material slides on the surface and moves. In the sheet material guiding device of Patent Document 1, a film of an ultraviolet curable resin containing conductive particles is formed on the surface so that the sheet material is not adversely affected by charging.

Japanese Unexamined Patent Publication No. 62-015996

However, even if a film containing conductive particles is formed, if the recording material moves from the transfer device to the fuser by rubbing against the transport guide structure, the charge of the transport guide structure cannot be sufficiently avoided. Therefore, as the guidance of the recording material is repeated, the electric charge may increase and the image on the recording material may be distorted.

Therefore, an object of the present invention is to suppress the charging of the member as compared with the case where the recording material moves from the transfer device to the fuser by rubbing against the transport guide structure.

The transport guide structure according to claim 1 is
By sandwiching the recording material in which the unfixed image is held on the front surface in the fixing region, toward the fixing region of the fuser that fixes the image on the recording material, from the back surface side of the recording material with respect to the front surface. The first guide that extends diagonally with respect to the recording material,
By transferring the image onto the recording material by electrostatic action, the image is projected from the back surface side onto the movement path of the recording material from the transfer device that holds the unfixed image to the first guide portion. The second guide portion whose angle with which the recording material intersects is larger than the angle at which the first guide portion intersects with the recording material.
Equipped with
The second guide portion has a plate-shaped portion protruding from the back surface side and a thickness in the traveling direction of the recording material fixed to the plate-shaped portion so as to protrude from the tip of the plate-shaped portion toward the recording material side. Is composed of flakes thinner than the plate-shaped portion .

The transport guide structure according to claim 2 is the transport guide structure according to claim 1 .
The base of the second guide portion is located on the back surface side with respect to the traveling direction of the recording material traveling straight from the transfer device.

The transport guide structure according to claim 3 is the transport guide structure according to claim 1 or 2.
The second guide portion is made of a material in which the flakes have a lower electrical resistance than the plate-shaped portion .

The transport guide structure according to claim 4 is the transport guide structure according to claims 1 to 3 .
A third guide unit for guiding the recording material to the first guide unit is provided between the first guide unit and the second guide unit.

The transport guide structure according to claim 5 is
An inrush guide unit that guides the entry of the recording material into the fixing region of the fuser that fixes the image on the recording material by sandwiching the recording material in which the unfixed image is held on the surface in the fixing region.
The image is transferred onto the recording material by electrostatic action to hold the unfixed image. The recording material is projected from the back surface side with respect to the front surface on the movement path of the recording material from the transfer device to the entry guide portion. A non-contact guide unit that guides the recording material to the entry guide unit in a non-contact manner by hitting the tip of the recording material that has moved from the transfer device.
Equipped with
The non-contact guide portion has a plate-shaped portion protruding from the back surface side and a thickness in the traveling direction of the recording material fixed to the plate-shaped portion so as to protrude from the tip of the plate-shaped portion toward the recording material side. It consists of flakes thinner than the plate-shaped part .

The image forming apparatus according to claim 6 is
A fixing device that fixes an image on the recording material by sandwiching a recording material in which an unfixed image is held on the surface in a fixing region, and a fixing device.
A transfer device that holds the unfixed image by transferring the image onto the recording material by electrostatic action.
A first guide portion extending diagonally with respect to the recording material from the back surface side of the recording material with respect to the front surface toward the fixing region of the fixing device.
The angle at which the recording material protrudes from the back surface side on the movement path of the recording material from the transfer device to the first guide unit and intersects with the recording material is larger than the angle at which the first guide unit intersects with the recording material. With a large second guide,
Equipped with
The second guide portion has a plate-shaped portion protruding from the back surface side and a thickness in the traveling direction of the recording material fixed to the plate-shaped portion so as to protrude from the tip of the plate-shaped portion toward the recording material side. It consists of flakes thinner than the plate-shaped part .

According to the transport guide structure according to claims 1 and 5 , and the image forming apparatus according to claim 6 , the member is a member as compared with the case where the recording material moves from the transfer device to the fuser by rubbing against the transport guide structure. Charging can be suppressed .

According to the transport guide structure according to claim 2 , charging in front of the second guide portion is suppressed as compared with the case where the root is located on the surface side.

According to the transport guide structure according to claim 3 , charging is suppressed as compared with the case where the electric resistances are equal.

According to the transport guide structure according to claim 4 , even a recording material with down curl can be guided to the fuser.

It is a schematic block diagram of the image forming apparatus corresponding to one Embodiment of this invention. It is a figure which shows the detailed structure around a guide part. It is a figure which shows the state which the paper reached the introduction part. It is a figure which shows the state which the paper reached the root of the protrusion. It is a figure which shows the state which the paper reached the tip of the protrusion. It is a figure which shows the state which the paper P has reached the downstream side guide 42. It is a figure which shows the state which the paper which caused the down roll reached the successor part. It is a figure which shows the state which the paper which caused the down roll reached the downstream side guide. It is a figure which shows the detailed structure around the guide part in 2nd Embodiment. It is a figure which shows the 1st modification of the protrusion. It is a figure which shows the 2nd modification of the protrusion. It is a figure which shows the 3rd modification of the protrusion.

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

FIG. 1 is a schematic configuration diagram of an image forming apparatus corresponding to an embodiment of the present invention.

The image forming apparatus 1 is a so-called direct transfer type monochrome printer.

The image forming apparatus 1 includes a photoconductor drum 10. The photoconductor drum 10 is rotatably supported by the drum support frame 10A and is driven by the photoconductor motor 16 to rotate in the direction of arrow A. A charger 11, an exposure device 12, and a developer 13 are provided around the photoconductor drum 10. Then, a toner image is formed on the surface of the photoconductor drum 10 through each process of charging by the charger 11, exposure by the exposure device 12, and development by the developer 13, and the toner image is displayed on the photoconductor drum 10. Be retained.

On the other hand, paper P (so-called cut paper), which is a kind of recording material, is conveyed in the direction of arrow X by a paper carrier (not shown), and a transfer region T sandwiched between the photoconductor drum 10 and a transfer device 20 described later is formed. pass. Then, the toner image on the photoconductor drum 10 is transferred onto the paper P while passing through the transfer region T. The remaining toner on the photoconductor drum 10 after the toner image is transferred in the transfer region T is removed from the photoconductor drum 10 by the cleaner 14.

The paper P to which the toner image has been transferred in the transfer region T is further conveyed in the direction of the arrow Y and sent to the fixing device 30. The fixing device 30 includes a heating roller 31 that rotates in the direction of arrow D, and a pressurizing roller 32 that rotates in the direction of arrow E. The heating roller 31 and the pressure roller 32 are in contact with each other to form a fixing region S. The paper P traveling in the direction of the arrow Y enters the fixing region S, and is heated and pressurized while passing through the fixing region S, and the toner image on the paper P is fixed on the paper P. As a result of this fixing, a fixed image composed of a fixed toner image is formed on the paper P. The fixing device 30 corresponds to an example of the fixing device according to the present invention.

The paper P on which the fixed image is formed by the fixing device 30 is sent out to the outside of the image forming device 1 by a paper feeder (not shown).

The transfer device 20 corresponds to an example of the transfer device according to the present invention, and includes a transfer roller 21, a pressure welding roller 22, a peeling roller 23, and an endless transfer belt 24 laid around these rollers. .. The transfer roller 21, the pressure contact roller 22, and the release roller 23 are rotatably supported by the transfer device support frame 20A.

The transfer roller 21 is driven by a transfer motor (not shown) and rotates in the direction of arrow B to drive the transfer belt 24. The transfer belt 24 is a resin belt having low elasticity, and is circulated and moved in the direction of the arrow C under the driving force of the transfer roller 21.

The transfer roller 21 is located on the upstream side in the paper traveling direction with respect to the rotation center axis of the photoconductor drum 10, and presses the transfer belt 24 against the photoconductor drum 10 from the inside of the transfer belt 24. The transfer roller 21 defines the upstream edge of the transfer region T in which the photoconductor drum 10 and the transfer belt 24 are in contact with each other.

Further, the pressure contact roller 22 is located on the downstream side in the paper traveling direction with respect to the rotation center axis of the photoconductor drum 10, and pushes the transfer belt 24 toward the photoconductor drum 10 from the inside of the transfer belt 24. Then, the edge on the downstream side of the transfer region T is defined by the pressure welding roller 22.

Further, the peeling roller 23 is a roller having a smaller diameter than the transfer roller 21, and the paper is placed on the transfer belt 24 by sharply bending the traveling direction of the transfer belt 24 by the peeling roller 23. The tip of P is peeled off from the transfer belt 24. Therefore, the peeling position where the paper P is peeled from the transfer belt 24 is near the apex of the peeling roller 23.

The image forming apparatus 1 is provided with a guide portion 40 that guides the paper P peeled off from the transfer belt 24 to the fixing apparatus 30 in the direction of the arrow Y. The guide portion 40 corresponds to the first embodiment of the transport guide structure of the present invention. The guide portion 40 includes an upstream guide 41 located on the upstream side of the paper P transport (that is, the transfer device 20 side) and a downstream guide 42 located on the downstream side of the paper P transport (that is, the fixing device 30 side). It is provided.

Hereinafter, the details of the guide unit 40 will be described.

FIG. 2 is a diagram showing a detailed structure around the guide portion 40.

The paper P guided to the guide unit 40 is guided to the fixing device 30 with the back surface side with respect to the front surface holding the unfixed toner image facing the guide unit 40. In the following description, for convenience, the lower side of FIG. 2 is referred to as "lower" regardless of the direction of gravity, and the upper side of FIG. 2 is referred to as "upper".

The downstream side guide 42 provided in the guide portion 40 has the downstream side (right side in FIG. 2) of the paper P conveyed higher than the upstream side, and is fixed in a state of being tilted with respect to the conveyed paper P. It extends toward the fixing region S of the device 30. Then, the downstream side guide 42 contacts the paper P from the back surface side of the paper P and guides the paper P. The downstream guide 42 corresponds to an example of the first guide unit according to the present invention, and also corresponds to an example of the inrush guide unit according to the present invention.

The upstream guide 41 provided in the guide portion 40 includes an introduction portion 43, a protruding portion 44, and a successor portion 45 in this order from the upstream side of the paper P transport.

The introduction portion 43 has a structure recessed on the back surface side of the paper P with respect to the first path R1 when the paper P travels straight from the peeling position 25 of the transfer device 20, and corresponds to an example of the recess as referred to in the present invention. do.

The protrusion 44 has a rib-like structure that extends linearly in the direction perpendicular to the paper surface of FIG. 2. The protrusion 44 protrudes from the back surface side of the paper P on the straight course R1, and the root of the protrusion 44 is located on the back surface side of the paper P with respect to the first course R1. Further, the protruding portion 44 protrudes in a state of being tilted with respect to the conveyed paper P, and the tilt with respect to the paper P is larger than the tilt of the upstream guide 41. The extension line of the second course R2 from the peeling position 25 toward the tip of the protrusion 44 reaches the downstream guide 42. On the other hand, the tip of the protrusion 44 is located below the third course R3 from the peeling position 25 toward the fixing region S. The protruding portion 44 corresponds to an example of the second guide portion referred to in the present invention, and also corresponds to an example of the non-contact guide portion referred to in the present invention.

The successor portion 45 is located between the protrusion 44 and the downstream guide 42, the height of the successor portion 45 is lower than that of the second course R2, and the successor portion 45 is a part described later. The paper P is guided to the downstream guide 42. This successor portion 45 corresponds to an example of the third guide portion referred to in the present invention.

Hereinafter, the transfer of the paper P by the guide unit 40 will be described in more detail.

FIG. 3 is a diagram showing a state in which the paper P reaches the introduction portion 43.

The paper P is in a charged state in order to hold an unfixed toner image on the surface. Therefore, even after the paper P is peeled off at the peeling position 25, the paper P is electrostatically pulled toward the transfer device 20, and the actual course of the paper P is directed to the lower side than the first course R1 shown in FIG. Become. As a result, the paper P reaches the introduction portion 43 and is guided to the protrusion portion 44. Since the paper P has elasticity, only the tip of the paper P comes into contact with the introduction portion 43.

FIG. 4 is a diagram showing a state in which the paper P reaches the root of the protrusion 44, and FIG. 5 is a diagram showing a state in which the paper P reaches the tip of the protrusion 44.

The paper P guided to the protrusion 44 by the introduction portion 43 heads upward so as to ride on the protrusion 44. After the tip has passed, the introduction portion 43 becomes non-contact with the paper P due to the stiffness of the paper P. Due to the presence of the recessed introduction portion 43 on the back surface side of the paper P, the tip of the paper P moves once to the back surface side and then rides on the protruding portion 44. As a result, the momentum that the tip of the paper P rides on the protrusion 44 increases as compared with the case where the introduction portion 43 does not exist. Further, since the root of the protrusion 44 is located below the first course R1 shown in FIG. 2, the distance that the tip of the paper P moves upward while riding on the protrusion 44 increases, and the tip of the protrusion 44 reaches the tip of the protrusion 44. The momentum of the paper P when it reaches is also increased.

FIG. 6 is a diagram showing a state in which the paper P reaches the downstream guide 42.

The inclination of the protrusion 44 with respect to the paper P is larger than the inclination of the downstream guide 42, for example, the inclination is 20 ° or more and 40 ° or less with respect to the horizontal. Therefore, the paper P that has reached the tip of the protrusion 44 reaches the downstream guide 42 substantially along the second course R2 shown in FIG. 2 with the force of riding on the protrusion 44. At this time, the transport speed of the paper P is, for example, 460 mm / sec.

At this time, since the successor portion 45 is lower than the second course R2, it does not come into contact with the paper P. That is, the paper P away from the peeling position 25 is guided to the downstream guide 42 in non-contact with other than the tip of the protrusion 44. Since the tip of the protrusion 44 is lower than the third course R3 shown in FIG. 2, it is possible to prevent the paper P riding on the protrusion 44 from directly reaching the fixing device 30 beyond the downstream guide 42.

Since the paper P comes into contact with only the tip of the protruding portion 44 and is guided to the downstream side guide 42, the charge of the paper P is hardly transmitted to the guide portion 40 side, and the charge of the guide portion 40 (particularly the upstream side guide 41) is charged. Is suppressed.

The paper P that has reached the downstream side guide 42 is guided to the fixing region S while sliding on the downstream side guide 42 having a small inclination with respect to the paper P.

By the way, some paper P may have a winding habit (so-called down roll) on the back surface side. In this embodiment, a successor portion 45 is provided between the protrusion 44 and the downstream guide 42 so that even such a paper can be reliably guided to the fixing region S.

7 and 8 are views showing how the down-rolled paper is guided, FIG. 7 shows a state in which the paper reaches the successor portion 45, and FIG. 8 shows a state in which the paper reaches the downstream side. The state of reaching the guide 42 is shown.

When the down-rolled paper P exceeds the protrusion 44, it faces downward and comes into contact with the successor portion 45. Then, the paper P is guided so as to slide on the surface of the successor portion 45 and heads toward the downstream guide 42.

When the paper P reaches the downstream guide 42, the paper P is guided so as to slide on the surface of the downstream guide 42 and heads toward the fixing region S of the fixing device 30. Further, after the tip of the paper P reaches the downstream side guide 42, the paper P moves from the protruding portion 44 to the downstream side guide 42 in a state where the paper P is almost in contact with the successor portion 45 due to the stiffness of the paper P and the momentum of transportation. You will be guided. Although the down roll does not occur very frequently, even when the down roll occurs, the paper P is guided in a non-contact state, so that the charging of the guide portion 40 is suppressed.

Next, a second embodiment of the present invention will be described. Since this second embodiment is the same as the first embodiment except that the structure of the protruding portion 44 is different, the same elements as those of the first embodiment are designated by the same reference numerals and the description will be duplicated. Is omitted.

FIG. 9 is a diagram showing a detailed structure around the guide portion 40 in the second embodiment.

The upstream guide 41 in the second embodiment is provided with a protruding portion 47 having a tip made of, for example, a polyimide or polyamide-imide sheet 46. The thickness of the sheet 46 is, for example, 0.1 mm, and the protruding portion 47 comes into contact with the paper P on the sheet 46 and guides the sheet 46 to the downstream guide 42. This sheet 46 corresponds to an example of flakes referred to in the present invention.

In the second embodiment, the contact area with the paper P is further smaller than that in the first embodiment, and the transfer of electric charge from the paper P to the protruding portion 47 (and by extension, to the upstream guide 41) is suppressed. .. Further, since the electric resistance value of the sheet 46 is lower than that of the other portions in the guide portion 40, for example, 1010 Ω or more and 1015 Ω or less, the accumulation of electric charges in the sheet 46 in contact with the paper P is suppressed.

In the embodiment described above, as the shape of the protrusions 44 and 47, a shape extending linearly in the width direction of the paper P is adopted, but a modified example which is not a linear shape will be described below.

FIG. 10 is a diagram showing a first modification example of the protruding portion.

FIG. 10 shows the shape of the protruding portion 71 as viewed from the traveling direction of the paper. The horizontal direction of FIG. 10 is the width direction of the paper, and the upper direction of FIG. 10 is the direction toward the paper.

In the protruding portion 71 of the first modification, the central portion 72a of the edge 72 corresponding to the tip toward the paper protrudes toward the paper side, and the end portion 72b of the edge 72 is lowered to the opposite side of the paper. Therefore, when guiding the paper, the protruding portion 71 comes into contact with the paper at the central portion 72a, and the end portion 72b is separated from the paper. Therefore, the protruding portion 71 of the first modification has a smaller contact area with the paper than the protruding portion extending linearly, and the electric field transfer from the paper to the protruding portion 71 is suppressed.

FIG. 11 is a diagram showing a second modification of the protruding portion.

FIG. 11 also shows the shape of the protruding portion 73 as seen from the traveling direction of the paper. The horizontal direction of FIG. 11 is the width direction of the paper, and the upper direction of FIG. 11 is the direction toward the paper.

In the protruding portion 73 of the second modification, the end portion 74b of the edge 74 corresponding to the tip toward the paper protrudes toward the paper side, and the central portion 74a of the edge 74 is lowered to the opposite side to the paper. Therefore, when guiding the paper, the protruding portion 73 comes into contact with the paper at the end portion 74b, and the central portion 74a is separated from the paper. Therefore, the protrusion 73 of the second modification also has a smaller contact area with the paper than the protrusion 73 extending linearly, and the electric field transfer from the paper to the protrusion 73 is suppressed.

FIG. 12 is a diagram showing a third modification example of the protruding portion.

FIG. 12 also shows the shape of the protruding portion 75 as seen from the traveling direction of the paper. The horizontal direction of FIG. 12 is the width direction of the paper, and the upper direction of FIG. 12 is the direction toward the paper.

In the protruding portion 75 of the third modification, a plurality of points 76a of the edge 76 corresponding to the tip toward the paper protrudes toward the paper side, and the points 76b between the plurality of points 76a are lowered to the opposite side of the paper. .. Therefore, when guiding the paper, the protruding portion 75 comes into contact with the paper at each portion 76a protruding toward the paper side, and the portion 76b lowered from the paper is separated from the paper. Therefore, the protruding portion 75 of the third modification also has a smaller contact area with the paper than the protruding portion extending linearly, and the electric field transfer from the paper to the protruding portion 75 is suppressed.

In the above description, an example in which a transfer belt type transfer device is used as the transfer device according to the present invention is shown, but the transfer device according to the present invention may be a transfer roll type transfer device.

Further, in the above description, an example in which the upstream side guide 41 and the downstream side guide 42 are separated as separate members is shown, but the first guide portion and the second guide portion referred to in the present invention are a series connected to each other. The entry guide portion and the non-contact guide portion referred to in the present invention may be each part in a series of members connected to each other.

Further, in the above description, an example in which a protruding portion 44 and a successor portion 45 are provided as each portion of the upstream guide 41 is shown, but the third guide portion referred to in the present invention is the first guide portion. It may be an independent member.

Further, in the above description, as an embodiment of the image forming apparatus of the present invention, a printer of a direct transfer method for directly transferring from a photoconductor roll to a recording material is exemplified, but the image forming apparatus referred to in the present invention is a photoconductor. An indirect transfer type device may be used, for example, via an intermediate transfer body between the roll and the recording material.

Further, in the above description, a monochrome printer is exemplified as an embodiment of the image forming apparatus of the present invention, but the image forming apparatus of the present invention may be a color printer, or may be a copying machine, a facsimile, or a multifunction device. There may be.

Further, the present invention has been invented for the purpose of solving the problem described in the "problem to be solved by the invention" column, but the configuration of the present invention is another form that does not solve this problem. Diversion to the intended purpose is not hindered, and a form in which the configuration of the present invention is diverted in this way is also an embodiment of the present invention.

1 ... image forming device, 10 ... photoconductor drum, 11 ... charger, 12 ... exposure device,
13 ... developer, 20 ... transfer device, 30 ... fixing device, 40 ... guide section,
41 ... upstream guide, 42 ... downstream guide, 43 ... introduction,
44, 47, 71, 73, 75 ... Protruding part, 45 ... Successor part, 46 ... Sheet

Claims (6)

By sandwiching the recording material in which the unfixed image is held on the front surface in the fixing region, toward the fixing region of the fuser that fixes the image on the recording material, from the back surface side of the recording material with respect to the front surface. A first guide portion extending diagonally with respect to the recording material, and
The image is electrostatically transferred onto the recording material to hold the unfixed image, and the image is projected from the back surface side onto the movement path of the recording material from the transfer device toward the first guide portion. The second guide portion whose angle with which the recording material intersects is larger than the angle at which the first guide portion intersects with the recording material.
Equipped with
The second guide portion has a plate-shaped portion protruding from the back surface side and a thickness in the traveling direction of the recording material fixed to the plate-shaped portion so as to protrude from the tip of the plate-shaped portion toward the recording material side. Is a transport guide structure characterized by being composed of flakes thinner than the plate-shaped portion . The transport guide structure according to claim 1, wherein the root of the second guide portion is located on the back surface side with respect to the traveling direction of the recording material traveling straight from the transfer device. The transport guide structure according to claim 1 or 2, wherein the second guide portion is made of a material having a lower electric resistance than the plate-shaped portion . Any one of claims 1 to 3 , wherein a third guide portion for guiding the recording material to the first guide portion is provided between the first guide portion and the second guide portion. The transport guide structure described in the section. An inrush guide unit that guides the entry of the recording material into the fixing region of the fuser that fixes the image on the recording material by sandwiching the recording material in which the unfixed image is held on the surface in the fixing region.
The image is electrostatically transferred onto the recording material to hold the unfixed image, and the image is projected from the back surface side with respect to the front surface on the movement path of the recording material from the transfer device toward the entry guide portion. A non-contact guide portion that guides the recording material to the entry guide portion in a non-contact manner by hitting the tip of the recording material that has moved from the transfer device.
Equipped with
The non-contact guide portion has a plate-shaped portion protruding from the back surface side and a thickness in the traveling direction of the recording material fixed to the plate-shaped portion so as to protrude from the tip of the plate-shaped portion toward the recording material side. Is a transport guide structure characterized by being composed of flakes thinner than the plate-shaped portion . A fixing device that fixes an image on the recording material by sandwiching a recording material in which an unfixed image is held on the surface in a fixing region, and a fixing device.
A transfer device that holds the unfixed image by transferring the image onto the recording material by electrostatic action.
A first guide portion extending diagonally with respect to the recording material from the back surface side of the recording material with respect to the front surface toward the fixing region of the fixing device.
The angle at which the recording material protrudes from the back surface side on the movement path of the recording material from the transfer device to the first guide unit and intersects with the recording material is larger than the angle at which the first guide unit intersects with the recording material. With a large second guide,
Equipped with
The second guide portion has a plate-shaped portion protruding from the back surface side and a thickness in the traveling direction of the recording material fixed to the plate-shaped portion so as to protrude from the tip of the plate-shaped portion toward the recording material side. Is an image forming apparatus characterized in that is composed of flakes thinner than the plate-shaped portion .

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