JP4454401B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus.

  2. Description of the Related Art Conventionally, in an image forming apparatus such as a serial impact printer, a static elimination mechanism such as a static elimination brush is provided in order to remove static electricity generated on a medium such as printing paper (see, for example, Patent Document 1).

  FIG. 2 is a schematic diagram showing the configuration of a conventional image forming apparatus.

  As shown in the figure, the image forming apparatus is, for example, a serial impact printer, and includes a carriage shaft 112, a print head 113, and a ribbon protector 122 that are attached in parallel to a platen 111 that is pivotally supported by a side frame (not shown). A carriage frame 114 slidably mounted on the carriage shaft 112, a tractor 115 for setting a sheet 121 such as continuous form paper as a medium, a stage 116 for setting a single sheet as a medium, and a front for conveying the medium It includes a roller 117 and a rear roller 118, a sheet guide 119 that secures a paper route as a medium conveyance path, and a static elimination bar 120 including a static elimination mechanism such as a static elimination brush that removes static electricity.

  Next, the operation of the image forming apparatus having the above configuration will be described.

  First, when the driving device operates according to a command from a control device (not shown), the paper 121 fed from the tractor 115 is sandwiched between the rear rollers 118 and conveyed under the print head 113. At this time, the carriage frame 114 on which the print head 113 and the ribbon protector 122 are mounted moves in the left-right direction (perpendicular to the drawing) along the carriage shaft 112, and printing is performed on the paper 121 by the print head 113. Is called.

The paper 121 is conveyed while printing is being performed, and the paper 121 is further sandwiched between the front rollers 117 and further conveyed. At this time, a static elimination mechanism such as a static elimination brush of the static elimination bar 120 disposed on the sheet guide 119 comes into contact with the paper 121 being conveyed. As a result, static electricity generated on the paper 121 is released from the static elimination bar 120 to the ground.
Japanese Patent Laid-Open No. 5-254683

  However, in the conventional image forming apparatus, since the neutralization bar 120 having a neutralization mechanism such as a neutralization brush is arranged, the structure is complicated, and the neutralization bar 120 is an expensive part. Cost becomes high.

  Further, as the member such as the sheet guide 119, a member generally called a plated steel plate is used, and further, an organic coating is coated thereon, so that static electricity generated on the paper 121 cannot be released.

  Accordingly, the static electricity generated on the paper 121 is accumulated without being neutralized, and the paper 121 sticks to the sheet guide 119, the stage 116, etc. due to the accumulated static electricity. Or the amount of movement of the paper 121 may be disturbed.

  The present invention solves the problems of the conventional image forming apparatus, removes a part of the low conductive coating applied to the member forming the medium conveyance path, and protrudes the part. To provide an image forming apparatus capable of effectively removing static electricity from a medium without using a complicated and expensive neutralization mechanism and preventing disturbance of the medium jam and the movement amount of the medium. With the goal.

Therefore, in the image forming apparatus according to the present invention, in the image forming apparatus having a low conductive coating on the surface of the conductive member and having a guide that forms a transport path for transporting the medium, the guide extends from the upper surface of the guide. A plurality of protrusions protruding toward the conveyance path, the protrusions being cut surfaces in which the conductive member original plate is exposed by removing the low-conductive coating by cutting a part of the guide; A cutting surface located above the upper surface of the guide is provided.

According to the present invention, in the image forming apparatus, the surface of the conductive member is coated with low conductivity and has a guide that forms a transport path for transporting the medium. The guide is transported from an upper surface of the guide. A plurality of protrusions protruding toward the road, the protrusions being cut surfaces in which the low conductive coating is removed by cutting a part of the guide and the conductive member original plate is exposed; A cutting surface located above the upper surface of the guide is provided.

  In this case, static electricity can be effectively discharged from the medium without using a complicated and expensive charge removal mechanism, and jamming of the medium and disturbance of the amount of movement of the medium can be prevented.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic diagram showing the configuration of the image forming apparatus according to the first embodiment of the present invention.

  In the figure, reference numeral 10 denotes an image forming apparatus such as a printer, which may be of any type such as an ink jet type, an electrophotographic type or a thermal transfer type, but will be described here as a serial impact printer. The image forming apparatus 10 includes a carriage shaft 12, a print head 13, and a ribbon protector 22 that are attached in parallel to a platen 11 that is pivotally supported by a side frame 23, which will be described later, and is slidable on the carriage shaft 12. An attached carriage frame 14, a tractor 15 for setting a sheet 21 such as a continuous form sheet as a medium, a stage 16 for setting a single sheet as a medium, a front roller 17 and a rear roller 18 for conveying the medium, and a medium It has a front lower sheet guide 19-1a, a rear lower sheet guide 19-1b, a front upper sheet guide 19-2a, and a rear upper sheet guide 19-2b as members forming a paper route as a conveyance path. When the front lower side sheet guide 19-1a, the rear lower side sheet guide 19-1b, the front upper side sheet guide 19-2a and the rear upper side sheet guide 19-2b are described in an integrated manner, the sheet guide 19 is used. explain. When the front lower sheet guide 19-1a and the rear lower sheet guide 19-1b are described in an integrated manner, they are described as the sheet guide lower 19-1, and the front upper sheet guide 19-2a and the upper rear sheet guide 19-1b. When the sheet guide 19-2b is described in an integrated manner, it will be described as the sheet guide upper 19-2.

  The front lower sheet guide 19-1a is formed with a protruding portion 29 as a discharging means that protrudes toward the paper 21. The protrusion 29 may be formed in any part of the front lower sheet guide 19-1a, and the front lower sheet guide 19-1a, the rear lower sheet guide 19-1b, and the front upper sheet. It may be formed on either the guide 19-2a or the back upper sheet guide 19-2b. Here, the protruding portion 29 is located on the front lower sheet guide 19-1a at a portion on the downstream side of the front roller 17 and in the vicinity of the front roller 17 with respect to the conveyance direction of the paper 21 indicated by an arrow in FIG. The case where it is formed will be described.

  Next, the configuration of the protruding portion 29 will be described.

  FIG. 3 is a cross-sectional view showing the configuration of the sheet guide in the first embodiment of the present invention, FIG. 4 is a perspective view showing the relationship between the protruding portion and the paper in the first embodiment of the present invention, and FIG. FIG. 6 is an enlarged perspective view showing the configuration of the protruding portion in the first embodiment of the present invention, FIG. 6 is a diagram showing a method of manufacturing the protruding portion in the first embodiment of the present invention, and FIG. It is a figure which shows the height of the protrusion part in 1 embodiment.

  The sheet guide 19 in the present embodiment is formed of a plated steel plate coated with an organic coating as a low conductive coating. In this case, as shown in FIG. 3, the sheet guide 19 has an original plate 19a made of a steel plate, a plated layer 19b is formed on both surfaces of the original plate 19a, and an organic film is formed on the plated layer 19b. A coating layer 19c made of is formed. Thus, since both sides of the original plate 19a made of a steel plate, which is a conductor, are in a state of being provided with a low conductive coating, even if the sheet 21 charged with static electricity contacts the surface of the sheet guide 19, Static electricity is difficult to flow through the sheet guide 19. The organic coating is a fingerprint-resistant coating that prevents fingerprints and the like from attaching.

  Further, since the sheet 21 is conveyed by the front roller 17 and the rear roller 18, the sheet 21 is raised above the surface of the sheet guide 19. For this reason, the sheet 21 and the sheet guide 19 do not come into contact with each other, so that the static electricity eliminating effect by the sheet guide 19 becomes extremely low.

  Therefore, as shown in FIGS. 4 and 5, the protruding portion 29 has a shape such that a part of the sheet guide 19 is cut and the cutting portion protrudes upward. In addition, an opening 29a as a remaining cutting portion is formed around the protruding portion 29. As a result, the cut surface 29b from which the original plate 19a is exposed contacts the paper 21, so that static electricity accumulated on the paper 21 flows through the sheet guide 19 and is eliminated. By chamfering the cut surface 29b, the original plate 19a is further exposed.

  The protruding portion 29 is manufactured as shown in FIG. First, a part of the sheet guide 19 as shown in FIG. 6 (a) is cut to form a tongue piece as shown in FIG. 6 (b). Subsequently, as shown in FIG. 6 (c), the tongue piece is bent downward from the root portion, and then bent from the middle of the tongue piece so that the tip portion faces upward, as shown in FIG. 6 (d). As shown in FIG. 5, a protrusion 29 is formed. In this case, the amount by which the cut surface 29b, which is the tip portion of the tongue piece, protrudes from the upper surface of the sheet guide 19, that is, the protrusion amount of the protruding portion 29 can be adjusted by the degree of bending of the tongue piece.

  The protrusion amount is adjusted so that the cut surface 29b is always in contact with the paper 21. Specifically, as shown in FIG. 7, the front roller 17 is adjusted to be the same as the dimension t protruding from the upper surface of the sheet guide 19. Further, in the protruding portion 29, it is desirable that the upstream end B in the conveyance direction of the sheet 21 is chamfered so as to prevent the leading end of the sheet 21 from being caught. Further, when printing on a cut sheet or the like, since it may be conveyed in the direction opposite to the arrow shown in FIG. 7, it is desirable that the downstream end A is also chamfered.

  Next, a configuration for flowing static electricity from the sheet guide 19 to the main body ground will be described.

  FIG. 8 is a first perspective view showing the frame of the image forming apparatus according to the first embodiment of the present invention, and FIG. 9 is a first enlarged view showing the frame of the image forming apparatus according to the first embodiment of the present invention. FIG. 10 is a perspective view showing an enlarged main part of FIG. 8, FIG. 10 is a second perspective view showing the frame of the image forming apparatus in the first embodiment of the present invention, and FIG. 11 is the first embodiment of the present invention. 10 is a second enlarged perspective view showing the frame of the image forming apparatus in FIG. 10, is an enlarged view of the main part of FIG. 10, FIG. 12 is a perspective view showing the lower cover of the image forming apparatus in the first embodiment of the present invention, and FIG. It is an expansion perspective view which shows the lower cover of the image forming apparatus in the 1st Embodiment of this invention, and is a principal part enlarged view of FIG.

  As shown in FIGS. 8 to 11, a left side frame 23L and a right side frame 23R are attached to the left and right of the seat guide lower 19-1, and a lower cover is attached to the lower ends of the left side frame 23L and the right side frame 23R. 24 is attached. When the left side frame 23L and the right side frame 23R are described in an integrated manner, the left side frame 23L and the right side frame 23R will be described as the side frame 23. Similarly to the sheet guide 19, the side frame 23 and the lower cover 24 are also formed by a plated steel plate coated with an organic coating, and have an original plate made of a steel plate, and a plating layer is formed on both surfaces of the original plate. A film treatment layer made of an organic film is formed on the plating layer.

  The seat guide lower 19-1, the left side frame 23L, the right side frame 23R, and the lower cover 24 are screwed together by a plurality of fixing screws 25. In this case, the seat guide lower 19-1, the left side frame 23L, the right side frame 23R and the lower cover 24 are formed with screw holes, and the fixing screws 25 are inserted into the holes. It is like that. Here, the screw hole is formed by subjecting a plated steel sheet coated with an organic coating to perforation, punching, etc., so that an original plate is formed on the inner peripheral surface of the screw hole. Exposed. Further, the fixing screw 25 is made of a conductor such as steel, and a low conductive film such as an organic film is not formed on the side surface. Therefore, the static electricity flowing into the sheet guide lower 19-1 flows from the side frame 23 to the lower cover 24 through the screwing portion.

  Here, as shown in FIGS. 12 and 13, a power line connection terminal device 26 is attached to the lower cover 24. The power line connecting terminal device 26 includes a ground terminal connected to a ground line included in the power line as the main body ground. One end of a ground wire 27 connected to a ground terminal serving as a main body ground is screwed to the lower cover 24 with a fixing screw 25. Therefore, the static electricity that has flowed into the lower cover 24 flows through the screwing portion and the ground wire 27 to the ground terminal as the main body ground. In FIGS. 12 and 13, 24a is a right screwing portion for screwing the right side frame 23R, and 24b is a left screwing portion for screwing the left side frame 23L.

  Next, the operation of the image forming apparatus 10 having the above configuration will be described.

  FIG. 14 is a first diagram showing the relationship between the protruding portion and the paper in the first embodiment of the present invention, and FIG. 15 is a first diagram showing the relationship between the protruding portion and the paper in the first embodiment of the present invention. FIG. 2 and FIG. 16 are third views showing the relationship between the protruding portion and the paper in the first embodiment of the present invention.

  First, when the driving device operates according to a command from a control device (not shown), the paper 21 fed from the tractor 15 is sandwiched between the rear rollers 18 and conveyed under the print head 13. At this time, the carriage frame 14 on which the print head 13 and the ribbon protector 22 are mounted moves in the left-right direction (perpendicular to the drawing) along the carriage shaft 12, and printing is performed on the paper 21 by the print head 13. Is called.

  The paper 21 is transported while printing is being performed, and the paper 21 is sandwiched between the front rollers 17 and further transported. Here, the relationship between the front roller 17 and the protrusion 29 is as shown in FIG. That is, the height of the lower front roller 17 and the height of the protruding portion 29 are the same. FIG. 14 shows a state where the paper 21 is not sandwiched between the front rollers 17. FIG. 14A is a front view, and FIG. 14B is a side view.

  Subsequently, when the sheet 21 is sandwiched between the front rollers 17, the sheet 21 is as shown in FIG. Here, FIG. 15A is a front view, and FIG. 15B is a side view. As shown in FIG. 15B, the upstream side of the protruding portion 29 in the transport direction of the paper 21 is chamfered and inclined, so that the leading edge of the paper 21 is not caught.

  Then, when the paper 21 is further conveyed, it is as shown in FIG. Here, FIG. 16A is a front view, and FIG. 16B is a side view. In this case, the sheet 21 comes into contact with the upper end of the protruding portion 29. Then, since the cut surface 29b from which the original plate 19a is exposed contacts the paper 21, the static electricity accumulated on the paper 21 flows through the sheet guide 19 and is discharged. The static electricity passes from the seat guide 19 through the side frame 23, the lower cover 24, and the ground wire 27, and is finally released to the ground terminal as the main body ground. As described above, the static electricity of the paper 21 is removed by contacting the protruding portion 29. As shown in FIG. 16B, since the height of the lower front roller 17 and the height of the protruding portion 29 are the same, the sheet 21 receives the resistance of the protruding portion 29 without receiving resistance. It is conveyed while in contact with the upper end.

  As described above, in the present embodiment, in the conveyance path of the sheet 21, the protruding portion is formed on the sheet guide 19 made of the plated steel plate in which the low conductive film is formed on both side surfaces of the original plate 19a made of the steel plate as the conductor. 29, and a cut surface 29b where the original plate 19a of the projecting portion 29 is exposed comes into contact with the paper 21. Thereby, static electricity generated in the paper 21 due to friction during conveyance can be removed. Therefore, it is possible to prevent sheet jamming due to sticking of the sheet 21 to the sheet guide 19 and the stage 16 caused by the accumulation of static electricity, disturbance of the movement amount of the sheet 21, and the like. Further, it is not necessary to add a static elimination mechanism such as a static elimination brush, and it is only necessary to form the protruding portion 29 on the sheet guide 19 that forms the conveyance path of the paper 21. Therefore, the configuration of the image forming apparatus 10 can be simplified. And cost can be reduced.

  Next, a second embodiment of the present invention will be described. In addition, about the thing which has the same structure as 1st Embodiment, the description is abbreviate | omitted by providing the same code | symbol. Also, the description of the same operations and effects as those of the first embodiment is omitted.

  FIG. 17 is a perspective view showing the relationship between the protruding portion and the paper in the second embodiment of the present invention, FIG. 18 is an enlarged perspective view showing the configuration of the protruding portion in the second embodiment of the present invention, and FIG. These are figures which show the method of manufacturing the protrusion part in the 2nd Embodiment of this invention.

  By the way, in the first embodiment, an opening 29a is formed in the sheet guide 19 as a remaining cutting portion when the protruding portion 29 is formed. Since the opening 29a has a relatively large area, there is a possibility that dust and paper dust may enter the image forming apparatus 10 through the opening 29a. Therefore, in the present embodiment, an opening having a large area is not formed in the sheet guide 19.

  In the present embodiment, by reducing the area of the opening 39a as the remaining cutting portion when the protruding portion 39 as the charge eliminating unit is formed, it is possible to prevent foreign matter from entering the image forming apparatus 10. It has become. In this case, as shown in FIGS. 17 and 18, the protrusion 39 cuts a part of the sheet guide 19 into a hook shape, and the tip of the hook portion of the sheet guide 19 faces upward. It is formed by bending and has a triangular shape. In addition, an opening 39a having a slit-like shape with a small area is formed around the protruding portion 39 as a remaining cutting portion. As a result, the cut surface 39b from which the original plate 19a is exposed contacts the paper 21 at the tip of the protruding portion 39, so that the static electricity accumulated on the paper 21 flows through the sheet guide 19 and is neutralized.

  The protrusion 39 is manufactured as shown in FIG. First, a part of the sheet guide 19 as shown in FIG. 19A is cut to form a bowl-shaped portion as shown in FIG. 19B. Subsequently, as shown in FIG. 19 (c), the protruding portion 39 is formed by bending the saddle-shaped portion from the middle so that the tip portion faces upward. In this case, the amount by which the cutting surface 39b, which is the tip of the saddle-shaped portion, protrudes from the upper surface of the sheet guide 19, that is, the protruding amount of the protruding portion 39 can be adjusted by the degree of bending of the saddle-shaped portion.

  Other configurations and operations are the same as those in the first embodiment, and a description thereof will be omitted.

  FIG. 20 is a main part enlarged view showing the relationship between the protruding portion and the sheet in the second embodiment of the present invention.

  In this case, since the protruding portion 39 is a triangle, a portion that is rubbed (rubbed) with the paper 21 becomes a point. Therefore, as compared with the first embodiment in which the sheet 21 is brought into contact with the surface, the friction between the sheet 21 and the protruding portion 39 is reduced, so that the probability of conveyance failure can be reduced.

  As described above, in the present embodiment, the same effect as in the first embodiment can be obtained.

  Furthermore, the area of the opening 39a as a remaining cutting portion when the protruding portion 39 is formed can be reduced, and foreign matter can be prevented from entering the image forming apparatus 10.

  Next, a third embodiment of the present invention will be described. In addition, about the thing which has the same structure as 1st and 2nd embodiment, the description is abbreviate | omitted by providing the same code | symbol. The description of the same operations and effects as those of the first and second embodiments is also omitted.

  FIG. 21 is a perspective view showing the relationship between the protruding portion and the paper in the third embodiment of the present invention, FIG. 22 is an enlarged perspective view showing the configuration of the protruding portion in the third embodiment of the present invention, and FIG. These are figures which show the method of manufacturing the protrusion part in the 3rd Embodiment of this invention.

  By the way, in the second embodiment, since the opening 39a as the remaining cutting portion when the protruding portion 39 is formed is opened in the sheet guide 19 with the hole facing upward, the end of the paper 21 is caught. there is a possibility. Therefore, in the present embodiment, an opening facing upward is not formed in the sheet guide 19. In this case, as shown in FIGS. 21 and 22, the protruding portion 49 of the sheet guide 19 has a throttle shape having gentle inclined surfaces toward the upstream side and the downstream side in the conveyance direction of the sheet 21. Formed in part. That is, the protrusion 49 has an inclined portion in the transport direction of the paper 21.

  Note that the opening 49 a generated by forming the protruding portion 49 is not opened upward, but is opened on both sides in the conveyance direction of the paper 21. Further, on both side surfaces of the protruding portion 49 in the transport direction of the paper 21, cut surfaces 49b where the original plate 19a is exposed are formed. In addition, the cut surface 49b from which the original plate 19a is exposed is not formed on the upper surface of the protruding portion 49, and the upper surface of the protruding portion 49 is formed of an organic film, that is, a coating surface, formed on both side surfaces of the original plate 19a. Therefore, since the upper surface of the protrusion 49 is smooth, the friction between the paper 21 and the protrusion 49 is low, and the possibility of poor conveyance is reduced. Note that the cut surface 49b from which the original plate 19a is exposed does not come into direct contact with the paper 21, but static electricity accumulated on the paper 21 flows into the sheet guide 19 by discharge and is eliminated.

  The protrusion 49 is manufactured as shown in FIG. First, a part of the sheet guide 19 as shown in FIG. 23A is cut, deformed as shown in FIG. 23B, and toward the upstream side and the downstream side in the transport direction of the paper 21. A diaphragm-shaped protrusion 49 having a gentle inclined surface is formed.

  Since the configuration and operation of other points are the same as those in the first and second embodiments, description thereof is omitted.

  As described above, in the present embodiment, since the cut surfaces 49b formed on both side surfaces of the protruding portion 49 are close to the paper 21, static electricity accumulated on the paper 21 is exposed to the cut surface 49b by discharge. It flows into the original plate 19a and is neutralized.

  Furthermore, since the opening 49a as the remaining cutting portion when the protruding portion 49 is formed is not opened upward, it is possible to prevent foreign matter from entering the inside of the image forming apparatus 10, and the paper 21 It is possible to reduce the possibility that the end of the hook will be caught.

  Next, a fourth embodiment of the present invention will be described. In addition, about the thing which has the same structure as the 1st-3rd embodiment, the description is abbreviate | omitted by providing the same code | symbol. Explanation of the same operations and effects as those of the first to third embodiments is also omitted.

  FIG. 24 is a perspective view showing the relationship between the protruding portion and the paper in the fourth embodiment of the present invention. FIG. 25 is an enlarged perspective view showing the configuration of the protruding portion in the fourth embodiment of the present invention. These are figures which show the method of manufacturing the protrusion part in the 4th Embodiment of this invention.

  In the present embodiment, as shown in FIGS. 25 and 26, the protruding portion 59 includes a circular flat surface portion 59c on the upper surface, and the diameter expands downward around the flat surface portion 59c. It is a conical stop to which inclined cone surfaces are connected. A circular opening 59a is formed at the center of the flat portion 59c, and the inner peripheral wall surface of the opening 59a is a cut surface 59b where the original plate 19a is exposed. In addition, the cut surface 59b where the original plate 19a is exposed is not formed on the upper surface of the flat portion 59c and the projecting portion 59 composed of a conical surface, and the upper surface of the projecting portion 59 is an organic coating formed on both side surfaces of the original plate 19a. That is, it consists of a coating surface. Therefore, since the upper surface of the protrusion 59 is smooth, the friction between the paper 21 and the protrusion 59 is low, and the possibility of poor conveyance is reduced. The cut surface 59b from which the original plate 19a is exposed does not come into direct contact with the paper 21, but static electricity accumulated on the paper 21 flows to the sheet guide 19 by discharge and is discharged.

  The protrusion 59 is manufactured as shown in FIG. First, as shown in FIG. 26B, a circular opening 59a is formed in a part of the sheet guide 19 as shown in FIG. Subsequently, when the drawing is performed with the opening 59a as a center to deform it, as shown in FIG. 26 (c), a conical protrusion 59 having a gently inclined surface is formed. .

  Since the configuration and operation of other points are the same as those in the first to third embodiments, description thereof will be omitted.

  FIG. 27 is a main part enlarged view showing the relationship between the protruding portion and the sheet in the fourth embodiment of the present invention.

  A cut surface 59b of an opening 59a formed at the center of the flat portion 59c is close to the paper 21. As a result, the static electricity accumulated in the paper 21 flows into the original plate 19a exposed on the cut surface 59b due to discharge, and finally is discharged to the ground terminal as the main body ground and is discharged.

  Next, a fifth embodiment of the present invention will be described. In addition, about the thing which has the same structure as 1st-4th embodiment, the description is abbreviate | omitted by providing the same code | symbol. Explanation of the same operations and effects as those in the first to fourth embodiments is also omitted.

  28 is a perspective view showing the relationship between the protruding portion and the paper in the fifth embodiment of the present invention, FIG. 29 is an enlarged perspective view showing the configuration of the protruding portion in the fifth embodiment of the present invention, and FIG. These are figures which show the method of manufacturing the protrusion part in the 5th Embodiment of this invention.

  In the present embodiment, as shown in FIGS. 28 and 29, the protrusion 69 is formed with a circular opening 69a at the upper end, and the diameter expands downward around the opening 69a. It is a conical stop to which an inclined conical surface is connected. The wall surface of the opening 69a is a cut surface 69b with the original plate 19a exposed. Further, a circular recess 69 c is formed around the protrusion 69, and the height of the protrusion 69 is adjusted so that the cut surface 69 b is always in contact with the paper 21. The cut surface 69b from which the original plate 19a is exposed does not come into direct contact with the paper 21, but static electricity accumulated on the paper 21 flows to the sheet guide 19 due to discharge and is eliminated. The paper contact surface is narrow, making it difficult to carry resistance.

  The protrusion 59 is manufactured as shown in FIG. First, as shown in FIG. 30B, a circular opening 69a is formed in a part of the sheet guide 19 as shown in FIG. Subsequently, when a drawing process is performed around the opening 69a to deform it, as shown in FIG. 30 (c), a conical projection 69 surrounded by a circular recess 69c is formed. .

  Since the configuration and operation of other points are the same as those in the first to fourth embodiments, description thereof is omitted.

  FIG. 31 is an essential part enlarged view showing the relationship between the protruding portion and the sheet in the fifth embodiment of the present invention.

  The static electricity accumulated on the sheet 21 flows into the original plate 19a exposed on the cut surface 69b by discharge, and finally is discharged to the ground terminal as the main body ground to be neutralized.

  In the present embodiment, the example in which the static elimination unit is applied to the sheet guide of the serial impact printer has been described. However, various types of printing apparatuses such as an electrophotographic printer, an ink jet printer, a copy machine, a facsimile machine, or any apparatus that moves paper are used. It can also be applied to static elimination.

  Alternatively, a part of the coating with low conductivity may be peeled off without cutting a part of the conveyance path, and the part may be protruded by knocking out or the like. In this case, since there is no gap in the conveyance path, paper dust does not fall to the bottom of the printer.

  Further, a coating process with high conductivity may be applied to the portion where the low conductive coating is peeled off.

  In addition, this invention is not limited to the said embodiment, It can change variously based on the meaning of this invention, and does not exclude them from the scope of the present invention.

1 is a schematic diagram illustrating a configuration of an image forming apparatus according to a first embodiment of the present invention. It is the schematic which shows the structure of the conventional image forming apparatus. It is sectional drawing which shows the structure of the sheet guide in the 1st Embodiment of this invention. It is a perspective view which shows the relationship between the protrusion part in 1st Embodiment of this invention, and a paper. It is an expansion perspective view which shows the structure of the protrusion part in the 1st Embodiment of this invention. It is a figure which shows the method of manufacturing the protrusion part in the 1st Embodiment of this invention. It is a figure which shows the height of the protrusion part in the 1st Embodiment of this invention. 1 is a first perspective view showing a frame of an image forming apparatus according to a first embodiment of the present invention. FIG. 9 is a first enlarged perspective view showing a frame of the image forming apparatus according to the first embodiment of the present invention, and is an enlarged view of a main part of FIG. 8. FIG. 3 is a second perspective view showing a frame of the image forming apparatus according to the first embodiment of the present invention. FIG. 11 is a second enlarged perspective view showing a frame of the image forming apparatus in the first embodiment of the present invention, and is an enlarged view of a main part of FIG. 10. FIG. 3 is a perspective view showing a lower cover of the image forming apparatus according to the first embodiment of the present invention. It is an expansion perspective view which shows the lower cover of the image forming apparatus in the 1st Embodiment of this invention, and is a principal part enlarged view of FIG. It is a 1st figure which shows the relationship between the protrusion part in 1st Embodiment of this invention, and a paper. It is a 2nd figure which shows the relationship between the protrusion part in 1st Embodiment of this invention, and a paper. It is a 3rd figure which shows the relationship between the protrusion part and paper in the 1st Embodiment of this invention. It is a perspective view which shows the relationship between the protrusion part in the 2nd Embodiment of this invention, and a paper. It is an expansion perspective view which shows the structure of the protrusion part in the 2nd Embodiment of this invention. It is a figure which shows the method of manufacturing the protrusion part in the 2nd Embodiment of this invention. It is a principal part enlarged view which shows the relationship between the protrusion part and paper in the 2nd Embodiment of this invention. It is a perspective view which shows the relationship between the protrusion part and the paper in the 3rd Embodiment of this invention. It is an expansion perspective view which shows the structure of the protrusion part in the 3rd Embodiment of this invention. It is a figure which shows the method of manufacturing the protrusion part in the 3rd Embodiment of this invention. It is a perspective view which shows the relationship between the protrusion part and the paper in the 4th Embodiment of this invention. It is an expansion perspective view which shows the structure of the protrusion part in the 4th Embodiment of this invention. It is a figure which shows the method of manufacturing the protrusion part in the 4th Embodiment of this invention. It is a principal part enlarged view which shows the relationship between the protrusion part in 4th Embodiment of this invention, and a paper. It is a perspective view which shows the relationship between the protrusion part and the paper in the 5th Embodiment of this invention. It is an expansion perspective view which shows the structure of the protrusion part in the 5th Embodiment of this invention. It is a figure which shows the method of manufacturing the protrusion part in the 5th Embodiment of this invention. It is a principal part enlarged view which shows the relationship between the protrusion part and the paper in the 5th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 19 Sheet guide 19-1 Sheet guide lower 19-1a Front lower sheet guide 19-1b Back lower sheet guide 19-2 Sheet guide upper 19-2a Front upper sheet guide 19-2b Back upper sheet guide 21 Paper 29, 39, 49, 59, 69 Projection

Claims (13)

In an image forming apparatus having a low conductive coating on the surface of a conductive member and having a guide for forming a conveyance path for conveying a medium,
The guide has a plurality of protrusions that protrude from the upper surface of the guide toward the conveyance path,
The protrusion has a cut surface that is located above the upper surface of the guide and is a cut surface from which the low conductive coating is removed by cutting a part of the guide to expose the conductive member original plate. An image forming apparatus. The image forming apparatus according to claim 1, wherein the low conductive coating is an organic coating. The image forming apparatus according to claim 2 , wherein the organic film is a fingerprint-resistant coating. The image forming apparatus according to claim 1, wherein a height at which the protruding portion protrudes is substantially the same as a height at which the lower transfer roller protrudes from the transfer path. The image forming apparatus according to claim 1, wherein the protrusion is in contact with the medium on a plane parallel to the conveyance path. The image forming apparatus according to claim 1, wherein the protruding portion protrudes in a triangular shape. The image forming apparatus according to claim 1, wherein the protruding portion includes an inclined portion in a conveyance direction of the medium. The image forming apparatus according to claim 1 , wherein the cut surface is a circular hole. The image forming apparatus according to claim 8 , wherein the cut surface is formed to open upward. The image forming apparatus according to claim 1, wherein the conveyance path is connected to a main body ground. The image forming apparatus according to claim 1 , wherein the cut surface is provided with a conductive coating. The image forming apparatus according to claim 1, wherein the cut surface is chamfered. The image forming apparatus according to claim 1, wherein a plurality of the protrusions are arranged in a direction perpendicular to a conveyance direction of the medium.

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