JP3748384B2 - Sheet material conveyor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sheet material conveying machine provided in an image forming apparatus (for example, a laser printer). In particular, the present invention relates to an improvement of a rotating member for conveying a sheet material.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an image forming apparatus using an electrophotographic system such as a printer, a copying machine, and a facsimile machine is provided with a plurality of conveyance rollers along a conveyance path as a mechanism for conveying a sheet material (paper). In addition, a fixing device for heating and fixing a toner image formed on the sheet material by an electrophotographic process is disposed in the middle of the conveyance path. As this fixing device, a heating roller system that applies heat and pressure simultaneously to a sheet material is generally used. That is, the sheet material is conveyed while being sandwiched between the heating roller and the pressure roller, and the sheet material is heated and pressed simultaneously to fix the toner image on the sheet material.
[0003]
In this toner image fixing operation, since the heating roller is heated to about 190 ° C., the periphery of the fixing device has an atmosphere of a considerably high temperature (for example, 90 ° C. to 100 ° C.).
[0004]
[Problems to be solved by the invention]
By the way, when a so-called paper jam in which the sheet material stagnates in the middle of the conveyance path occurs, the user needs to open the conveyance path and remove the stagnation sheet material. For example, Japanese Patent Laid-Open No. 5-188818 discloses a configuration in which a heating roller is covered with a protective cover. This is to prevent the user's hand from coming into direct contact with the high-temperature heating roller even if a paper jam occurs around the fixing device.
[0005]
However, the heat generated from the heating roller is dissipated to the other transport rollers, and the transport rollers are often quite hot. In particular, as disclosed in the above publication, a so-called vertical conveyance type image forming apparatus in which a conveyance path extends in the vertical direction (this type of image forming apparatus discharges a sheet material after image formation to the upper part of the apparatus. Therefore, the installation space of the apparatus can be reduced, and in recent years, the heat generated from the heating roller is radiated upward, and the downstream of the fixing unit. In some cases, the discharge roller disposed on the side (upper side) for discharging the sheet to the discharge tray is at a considerably high temperature (for example, about 100 ° C.).
[0006]
In such a situation where the paper discharge roller is at a high temperature, when the paper jam release operation is performed, the user's hand may come into contact with the high temperature paper discharge roller. For this reason, the user is forced to perform an operation of removing the sheet material while paying attention not to contact the paper discharge roller, and there is a problem that it is difficult to perform a paper jam release operation.
[0007]
As one means for solving this problem, the entire paper discharge roller disposed above the fixing device is covered with a protective cover, and the user's hand directly contacts the paper discharge roller when the paper jam is released. It can be considered not to.
[0008]
However, this configuration requires a new protective cover, which increases the number of parts of the device, leading to an increase in cost, and requires a mounting operation of the protective cover when the device is manufactured. It will be complicated.
[0009]
The present invention has been made in view of the above points, and the object of the present invention is to a sheet material conveying machine including a rotating body (conveying roller) for conveying a sheet material along a conveying path. An object of the present invention is to eliminate the problem of a user coming into contact with a high-temperature rotating body without adopting a configuration in which the rotating body is covered with a protective cover.
[0010]
[Means for Solving the Problems]
-Summary of invention-
In order to achieve the above object, the present invention provides a situation in which the rotating body is heated by covering the surface of the rotating body that conveys the sheet material with a coating material having a relatively low thermal conductivity. Even if the user touches, the degree of heat felt by the user can be reduced.
[0011]
    -Solution-
  Specifically, the present invention provides:After the developer has been transferred from the photoreceptor, the sheet material on which the developer has been fixed by the fixing device is sandwiched from both sides.The sheet material is conveyed along the conveyance path by rotating while rotating.A pair ofA sheet material conveyance machine provided with a rotating body is assumed. For this sheet material conveyorOne rotating body of the pair of rotating bodies is disposed on a space side where a user inserts a hand during a jam release operation when a jam occurs in the sheet material, while the other rotating body is disposed on the sheet material. Of the both surfaces, the developer is transferred from the photosensitive member and disposed at a position in contact with one surface on which the developer is fixed by the fixing device. Also, the one rotating body is made of metalHeartwood and the surface of this heartwoodThe bearing part which is both ends is excludedA covering material covering substantially the whole and having a lower thermal conductivity than the core material is provided.Then, the other rotating body is provided with a metal core, and a holding body that holds the sheet material between the one rotating body is provided, and the holding body is provided on a part of the surface of the core. By forming the core material, the core material is exposed to the conveyance path at portions other than the formation position of the sandwiching body.
[0012]
  With this particular matter, for exampleOne of the aboveEven if the rotating body is placed in a relatively high temperature atmosphere and the rotating body itself is also at a relatively high temperature,This oneThe degree of heat felt when touching the rotating body can be made lower than when the core material is exposed. Specifically, when this rotating body is applied as a sheet material conveying roller or the like of the image forming apparatus, when the inside of the image forming apparatus has a relatively high temperature atmosphere, It is not necessary to remove the sheet material while paying attention not to contact the roller (rotating body), and the workability of the paper jam release operation is improved. In addition, since it is not necessary to employ a configuration in which the rotating body is covered with a protective cover, the number of parts of the device can be reduced.
  As a specific arrangement state of the rotator, each rotator is disposed above the vicinity of the fixing device, and the other rotator is disposed above the heating fixing roller of the pair of rollers constituting the fixing device.
[0013]
  Specific examples of the rotating body include the following. That meansOne of the aboveThe rotating body is formed with a larger diameter than the core material andThe otherRotating bodyThe sandwich ofA sandwiching body for sandwiching the sheet material between the two is provided. And this clamping body and coating | covering material are integrally formed with the same material. According to this configuration, the clamping body and the covering material can be simultaneously formed at the time of manufacturing the rotating body, and the manufacturing cost can be reduced.
[0015]
  In addition, the transport path can be freely opened so that a sheet material stagnated in the middle of the path can be taken out,With the opening of the transport path, the one rotating body is placed on the space side where the user inserts his / her hand.ExposedConfiguration andIn this case, the user is likely to come into contact with the rotating body when taking out the stagnant sheet material, but the degree of heat can be kept low even if contact is made.
[0016]
Specific examples of the covering material include the following. First, the covering material is made of a material having heat resistance. Moreover, the outer surface is formed in a shape that increases the surface area of the covering material. In the case of the former configuration, the rotating body is not easily affected by heat, and the conveyance performance and protection performance of the sheet material can be stably maintained over a long period of time. In the latter configuration, grooves are formed on the outer surface of the covering material, or irregularities are provided. In this case, even if the user contacts the rotating body, since the contact area is small, the degree of heat felt by the user can be further reduced.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present embodiment, a case where the sheet material conveying machine according to the present invention is applied to a laser printer as an image forming apparatus will be described.
[0018]
-Description of the overall configuration of the laser printer-
FIG. 1 schematically shows the internal configuration of a laser printer 1 according to this embodiment. As shown in FIG. 1, the laser printer 1 includes a laser scanning unit 2, an electrophotographic process unit 3 that forms an image on a recording sheet P as a sheet material, and the supply of the recording sheet P to the electrophotographic process unit 3. A paper feeding / conveying unit 4 for carrying the paper and the recording paper P is provided. Hereinafter, each part will be described.
[0019]
<Description of Laser Scanning Unit 2>
The laser scanning unit 2 scans and exposes the photosensitive drum 31 of the electrophotographic process unit 3 with laser light on the basis of image data received from an external device such as a personal computer. It forms a latent image.
[0020]
<Description of electrophotographic process section 3>
The electrophotographic process unit 3 includes the photosensitive drum 31. The photosensitive drum 31 rotates in a direction indicated by an arrow in FIG. 1, and an electrostatic latent image is formed on the outer peripheral surface by the laser scanning unit 2.
[0021]
Further, around the photosensitive drum 31, a charging roller 32, a developing unit 33, a transfer unit 34, a cleaning unit 35, and a static eliminator (not shown) are arranged.
[0022]
The charging roller 32 charges the surface of the photosensitive drum 31 before the electrostatic latent image is formed to a predetermined potential. The developing unit 33 develops the electrostatic latent image formed on the surface of the photosensitive drum 31 into a visible image with a developer (toner or the like). The transfer unit 34 transfers the developer image formed on the surface of the photosensitive drum 31 onto the recording paper P. The cleaning unit 35 removes the developer remaining on the surface of the photosensitive drum 31 after the developer transfer. The static eliminator removes residual charges on the surface of the photosensitive drum 31.
[0023]
Thus, when an image is formed on the recording paper P, the surface of the photosensitive drum 31 is charged to a predetermined potential by the charging roller 32, and an electrostatic latent image is formed on the surface of the photosensitive drum 31 by the laser scanning unit 2. It is formed. Thereafter, the developing unit 33 develops a visible image by the developer on the surface of the photosensitive drum 31, and the image by the developer is transferred by the transfer unit 34 to the recording paper P fed from the paper feeding / conveying unit 4. Is done. Thereafter, the recording paper P is heated by a fixing device 5 provided on a conveyance path 42, which will be described later, and an image by the developer is fixed. On the other hand, the developer remaining on the surface of the photosensitive drum 31 is removed by the cleaning unit 35, and the residual charge on the surface of the photosensitive drum 31 is removed by the static eliminator. Thereby, one cycle of the image forming operation (printing operation) on the recording paper P is completed. By repeating this cycle, it is possible to continuously form images on a plurality of recording sheets P, P,. A collecting means such as a transport pipe (not shown) is provided between the cleaning unit 35 and the developing tank of the developing unit 33, and the toner collected by the cleaning unit 35 is supplied to the developing unit 33 and reused. It can be used.
[0024]
<Description of Paper Feeding Unit 4>
The paper feeding / conveying unit 4 includes a paper cassette 41 and a conveyance path 42 (path indicated by a one-dot chain line in the drawing) extending upward from the discharge side of the paper cassette 41 and extending to the discharge unit 11 formed at the upper part of the laser printer. I have. The sheet feeding / conveying unit 4 takes out the recording sheets P, P,... Stored in the sheet cassette 41 one by one, and removes the recording sheet P between the photosensitive drum 31 of the electrophotographic process unit 3 and the transfer unit 34. Is supplied at a predetermined timing. When the recording paper P is set in the paper cassette 41, the paper cassette 41 is pulled out to the front side of the laser printer 1 so that the recording paper P is supplied or the recording paper P is exchanged.
[0025]
In addition, the fixing device 5 is disposed in the conveyance path 42 on the discharge side of the transfer unit 34. The fixing device 5 includes a pair of fixing rollers 51 and 52. By these fixing rollers 51 and 52, the developer image on the recording paper P that has passed through the transfer unit 34 is heated and fixed and discharged to the discharge unit 11.
[0026]
Hereinafter, the configuration of the fixing device 5 serving as a heat generation source in the printer 1 will be described in detail. The fixing device 5 is disposed at a plurality of positions in the longitudinal direction of each of the rollers 51 and 52 (direction perpendicular to the paper surface of FIG. 1) corresponding to the fixing rollers 51 and 52, respectively. Separation claws 53 and 54 are provided.
[0027]
As the fixing rollers 51 and 52, the one on the right side in the figure is a heating and fixing roller 51 incorporating a heater 55 made of a halogen lamp or the like. The heat fixing roller 51 includes a rubber layer made of silicon rubber or a coating layer such as Teflon on the surface of a shaft member such as aluminum. On the other hand, the left side in the figure is a pressure roller 52 pressed against the heat fixing roller 51 with a predetermined pressure. The pressure roller 52 also includes a rubber layer made of silicon rubber on the surface of a shaft member such as aluminum. The heater may be incorporated in the pressure roller 52.
[0028]
In the vicinity of the heat fixing roller 51 and the pressure roller 52, the peeling claws 53 and 54 are disposed, respectively. The peeling claws 53 and 54 are supported so as to be rotatable about a horizontal axis, and the tip portions are pressed against the outer peripheral surfaces of the rollers 51 and 52 with a predetermined pressing force. As a result, even if the recording paper P sticks to any of the rollers 51 and 52 and the winding occurs, the front end of the recording paper is separated from the outer peripheral surface of the rollers 51 and 52 by the front ends of the separation claws 53 and 54. Can do. Thus, the recording paper P is favorably conveyed toward the discharge unit 11.
[0029]
A temperature sensor 56 made of a thermistor is attached to the heat fixing roller 51. The temperature of the heat fixing roller 51 is detected by the temperature sensor 56, and the detected temperature is transmitted to a fixing control unit (not shown). The fixing control unit maintains the temperature of the heat fixing roller 51 at a predetermined heating temperature. The operation of the power supply unit that is not controlled is controlled to turn ON / OFF the energization to the heater 55. As a result, the heat fixing roller 51 is maintained at a predetermined heating temperature (for example, around 190 ° C.).
[0030]
The heat fixing roller 51 and the pressure roller 52 are covered with protective covers 51a and 52a, respectively. The protective covers 51a and 52a are for suppressing heat from the heat fixing roller 51 from being radiated to the outside. Since the protective covers 51a and 52a cover substantially the entire sides of the heat fixing roller 51 and the pressure roller 52, heat radiation to the sides is effectively prevented.
[0031]
Further, a pair of transport rollers is provided at a plurality of locations on the transport path 42. With these conveyance roller pairs, the recording paper P taken out from the paper cassette 41 is smoothly conveyed to the discharge unit 11 through the transfer unit 34 and the fixing device 5. Specifically, as these conveyance rollers, a pickup roller 44 and a feed roller pair 45 arranged on the paper discharge side of the paper cassette 41, and arranged between the feed roller pair 45 and the electrophotographic process unit 3. A first paper feed roller pair 46 and a second paper feed roller pair (PS roller) 47, and a first paper discharge roller pair 48 and a second paper discharge roller pair 49 provided on the downstream side of the fixing device 5 are provided. ing. In particular, the first paper discharge roller pair 48 is disposed immediately above the fixing device 5.
[0032]
<Other configurations>
Further, a control box 12 is disposed below the laser scanning unit 2. The control box 12 includes a process control unit (PCU) board that controls the electrophotographic process unit 3, an interface board that receives image data from the outside of the printer, and predetermined image processing for the image data received from the interface board. And an image control unit (ICU) board for scanning and recording as an image by the laser scanning unit 2, and a power supply unit for supplying power to these various boards and units.
[0033]
In this manner, the laser printer 1 is connected to an image processing apparatus (external connection device) such as a personal computer, and records and outputs image data from the external connection device.
[0034]
Further, the laser printer 1 can be opened on the left side surface in the drawing. That is, the side surface of the laser printer 1 is constituted by a door 13 that can be freely opened and closed, and the door 13 can be opened as necessary. The door 13 and the printer main body 14 are separated from each other with the conveyance path 42 as a boundary. Therefore, in particular, when a so-called paper jam occurs in which the recording paper P stagnates in the transport path 42, the recording paper P in the transport path 42 can be easily removed by opening the door 13. It is like that. FIG. 2 shows a state in which the door 13 is opened. As shown in this figure, the door 13 and the printer main body 14 are connected by a connecting frame 15 extending in the horizontal direction, and the door 13 slides in the horizontal direction relative to the printer main body 14 to open and close the side surface of the laser printer 1. It is like that. For example, when the paper jam of the recording paper P occurs in the fixing device 5, the door 13 is opened as shown in FIG. 2, and the recording paper P is pulled out and removed in the direction of arrow A, and the paper jam state is released. Will be. In order to facilitate the removal of the recording paper P when a paper jam occurs in the fixing device 5, the pair of transport guides 16A and 16B that form the transport path 42 on the downstream side of the fixing device 5 are 16A is attached to the printer main body 14 side, and the other 16B is attached to the door 13 side. That is, as shown in FIG. 2, when the door 13 is opened, the conveyance guides 16A and 16B are separated from each other, the conveyance path 42 is opened, and the recording paper P can be easily removed.
[0035]
The door 13 is provided with a paper reversing unit 17. The sheet reversing unit 17 is used when image formation is performed on both the front and back sides of the recording sheet P. That is, after the recording paper P on which image formation has been performed on one side is guided to the conveyance path 17a in the paper reversing unit 17 by kickback conveyance, the recording paper P is conveyed again to the electrophotographic process unit 3 to thereby reverse the back surface. It is configured to be able to form an image.
[0036]
<Description of Configuration of First Discharge Roller Pair 48>
Next, a description will be given of the first paper discharge roller pair 48 that constitutes the sheet material conveying machine that is a feature of this embodiment. The first paper discharge roller pair 48 is composed of a driving roller 61 as a rotating body located on the left side in FIGS. 1 and 2 and a driven roller 62 located on the right side. The recording paper P is conveyed toward the discharge unit 11 while the recording paper P is sandwiched.
[0037]
As shown in FIG. 3, the driven roller 62 includes large-diameter clamping rollers 62b, 62b,... At four locations in the longitudinal direction of a metal (for example, aluminum) shaft member 62a. The sandwiching roller 62b is formed of an elastic rubber material having heat resistance. Specifically, CR (chloroprene rubber), EPDM (ethylene propylene rubber), etc. are adopted.
[0038]
The feature of this embodiment is the configuration of the drive roller 61. The drive roller 61 includes large-diameter clamping rollers 61b, 61b,... As clamping bodies at four locations in the longitudinal direction of a shaft member 61a as a metal (for example, aluminum) core material. The arrangement position of the nipping roller 61b is a position facing the nipping roller 62b of the driven roller 62, whereby the recording paper P is nipped between the nipping rollers 61b and 62b of the driving roller 61 and the driven roller 62. It is designed to be transported. Also in the driving roller 61, the clamping roller 61b is formed of an elastic rubber material having heat resistance. Specifically, CR (chloroprene rubber), EPDM (ethylene propylene rubber), etc. are adopted. The shaft member 61 a of the drive roller 61 is covered with a covering material 63. The covering material 63 is a cylindrical member formed of the same rubber material as the sandwiching roller 61b and integrally formed with the sandwiching roller 61b. The outer diameter of the covering material 63 is set smaller than that of the sandwiching roller 61b. Has been. And this coating | covering material 63 is arrange | positioned so that the whole shaft member 61a may be covered except the both ends of the shaft member 61a. Specifically, the outer diameter of the sandwiching roller 61b is 16 mm, and the outer diameter of the covering material 63 is 12 mm. The number and outer diameter of the sandwiching rollers 61b and the outer diameter of the covering material 63 are not limited to those described above.
[0039]
The material of the covering material 63 is not limited to that described above, and any material having heat resistance and lower thermal conductivity than the shaft member 61a can be used. That is, the covering material 63 is not necessarily formed of the same rubber material as that of the sandwiching roller 61b, and may be formed of a material different from that of the sandwiching roller 61b.
[0040]
Further, when the drive roller 61 is manufactured, FIG. 4 (FIG. 4a is a sectional view of the molding die in the molding portion of the sandwiching roller 61b, and FIG. 4b is a sectional view of the molding die in the molding portion of the covering material 63). As shown, the machined shaft member 61a is placed on the lower mold 71 of the mold 7 and the upper mold 72 is closed, and then the cavity 73 of the mold 7 is filled with a rubber material. The cavity 73 of the mold 7 is formed so as to mold the sandwiching roller 61b and the covering material 63 into a predetermined shape. After filling with the rubber material, the mold is opened to obtain a driving roller 61 as shown in FIG. The drive roller 61 is substantially entirely covered with a rubber material except for both end portions thereof. Both end portions of the driving roller 61 become bearing portions by a bearing member (not shown) disposed inside the printer, or power transmission portions that receive a driving force from a driving motor. For this reason, when the door 13 of the printer 1 is opened with the driving roller 61 disposed in the printer 1, the shaft member 61a is not exposed, and the portion of the driving roller 61 that faces the open space is substantially the whole. Is covered with a rubber material.
[0041]
As described above, when a material different from the sandwiching roller 61b is adopted as the material of the covering material 63, the covering material 63 and the sandwiching roller 61b are individually formed. At this time, for example, a through-hole for inserting the shaft member 61a is formed in the center of the covering material 63 and the sandwiching roller 61b, and the plurality of covering materials 63 and the sandwiching rollers 61b are alternately arranged with respect to the shaft member 61a. It is possible to obtain the drive roller 61 by inserting it through the.
[0042]
-Explanation of jam recovery work-
Next, a jam recovery operation for removing the recording paper P when a paper jam of the recording paper P occurs in the peripheral portion of the fixing device 5 will be described.
[0043]
When this paper jam occurs, first, as shown in FIG. 2, the door 13 is slid in the horizontal direction with respect to the printer main body 14, and the side surface of the laser printer 1 is opened. Accordingly, a jam processing space C for removing the recording paper P is formed between the door 13 and the printer main body 14. Then, the user inserts his / her hand into the space between the door 13 and the printer main body 14 to grip the recording paper P, and pulls it out in the direction indicated by the arrow A in FIG. At this time, the heat fixing roller 51 of the fixing device 5 is at a considerably high temperature, and the heat radiation is also transmitted to the pressure roller 52, and the pressure roller 52 is also at a high temperature. However, as described above, since the heat fixing roller 51 and the pressure roller 52 are respectively covered with the protective covers 51a and 52a, the user's hand does not directly contact the heat fixing roller 51 and the pressure roller 52. .
[0044]
In the case of the printer 1, since the transport path 42 extends in the vertical direction, both the upper and lower sides are open to the protective covers 51a and 52a. For this reason, the heat of the heat fixing roller 51 is radiated upward, and there is a possibility that the rollers 61 and 62 of the first paper discharge roller pair 48 become high temperature due to this heat radiation. However, as described above, in the driving roller 61 facing the jam processing space C, since almost the entire portion facing the space C is covered with the rubber material, the heat felt even if the user's hand touches. The degree of is lower than when the metal shaft member 61a is exposed. This eliminates the need for the user to be careful not to touch the drive roller 61 when removing the recording paper P (because it does not feel much heat even if contacted), and the workability of the jam recovery work is improved. It is good.
[0045]
After the recording paper P is removed in this manner, the door 13 is slid in the horizontal direction toward the printer body 14, and the side surface of the laser printer 1 is closed as shown in FIG. As a result, the jam recovery operation ends.
[0046]
-Effect of the embodiment-
As described above, according to the present embodiment, substantially the entire driving roller 61 positioned above the fixing device 5 and facing the jam processing space C during the jam recovery operation is covered with the rubber covering material 63. Thus, the degree of heat felt even when the user's hand touches the drive roller 61 during the jam recovery operation can be kept low. For this reason, the workability of the jam recovery work can be obtained satisfactorily, and the jam recovery work can be performed smoothly in a short time.
[0047]
-Modification-
Next, a modified example of the present invention will be described. In this modification, the outer surface shape of the covering material 63 is changed, and other configurations are the same as those of the above-described embodiment. For this reason, only the outer surface shape of the covering material 63 will be described here.
[0048]
As shown in FIG. 5, the covering material 63 of the driving roller 61 according to this example has irregularities formed at a plurality of locations. Specifically, a relatively large-diameter ring-shaped portion 63 a that extends over the circumferential direction of the drive roller 61 and a relatively small-diameter ring-shaped portion 63 b that also extends over the circumferential direction of the drive roller 61 are the drive roller 61. It is formed in a shape that continues alternately in the longitudinal direction.
[0049]
According to this configuration, even if the user contacts the drive roller 61 during the jam recovery operation, the contact area can be reduced, and the degree of heat felt by the user can be further reduced.
[0050]
-Other embodiments-
In the above-described embodiment, the case where the sheet material conveyance device according to the present invention is applied to the vertical conveyance type laser printer 1 has been described. The present invention is not limited to this, and can be applied to other types of laser printers.
[0051]
Further, the covering material 63 is provided on the roller 61 disposed in the vicinity of the fixing device 5, but the present invention can also be applied to a roller disposed at another position. Furthermore, the present invention can be applied to an image forming apparatus other than a laser printer. Further, the heat generation source is not limited to the fixing device 5, and the present invention can be applied to a roller disposed in the vicinity of a device that generates heat.
[0052]
【The invention's effect】
As described above, in the present invention, the surface of the rotating body that conveys the sheet material is covered with the coating material having a relatively lower thermal conductivity than the core material. Thereby, even if a user contacts in the condition where a rotary body is high temperature, the degree of the heat which a user feels can be suppressed low. For this reason, when this rotating body is applied as a roller for conveying a sheet material of the image forming apparatus, when the inside of the image forming apparatus is in a relatively high temperature atmosphere, the user must manually move the rotating body during the paper jam release operation. It is not necessary to remove the sheet material while paying attention not to touch the sheet, and the workability of the paper jam release operation is improved. In particular, when the rotating body is disposed above a heat generation source such as a fixing device, it is highly likely that the rotating body is heated due to heat radiation from the fixing device. Workability of the paper jam release work is improved.
[0053]
In addition, since it is not necessary to employ a configuration in which the rotating body is covered with a protective cover, the number of parts of the apparatus can be reduced, and the manufacturing cost can be reduced and the assembling work can be simplified.
[0054]
Furthermore, when the sandwich body that sandwiches the sheet material with the counterpart rotating body and the covering material are integrally formed of the same material, the sandwich body and the covering material can be simultaneously formed at the time of manufacture of the rotating body. The cost can be reduced, and the manufacturing cost and the time required for manufacturing the rotating body can be reduced.
[0055]
In addition, when the outer surface is formed in a shape that increases the surface area of the covering material, even if the user contacts the rotating body, the contact area becomes smaller, so the degree of heat felt by the user is further increased. It becomes possible to keep it low. Moreover, since the heat dissipation of the rotating body is improved, the temperature rise of the rotating body can be suppressed.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an outline of an internal configuration of a laser printer according to an embodiment.
FIG. 2 is a view corresponding to FIG. 1 showing a state in which a door of the laser printer is opened.
FIG. 3 is a perspective view showing a driving roller and a driven roller constituting the first paper discharge roller pair.
FIG. 4 is a diagram for explaining a manufacturing process of a drive roller.
FIG. 5 is a perspective view showing a driving roller in a modified example.
[Explanation of symbols]
1 Laser printer
42 Transport route
5 Fixing device (heat source)
61 Drive roller (rotating body)
61a Shaft member (core material)
61b Clamping roller (clamping body)
63 Coating material
P Recording paper (sheet material)

Claims (6)

After the developer is transferred from the photoconductor, the sheet material on which the developer has been fixed by the fixing device is rotated while being sandwiched from both the front and back sides , whereby a pair of rotating bodies that convey the sheet material along the conveyance path In the provided sheet material transport machine,
One of the pair of rotating bodies is disposed on the space side where the user inserts a hand during a jam release operation when a jam of the sheet material occurs,
The other rotating body is disposed at a position in contact with one surface of the sheet material on which the developer is transferred from the photosensitive member and the developer is fixed by the fixing device.
The one rotating body includes a metal core material and a covering material that covers substantially the entire surface of the core material except for the bearing portions that are both end portions and has a lower thermal conductivity than the core material ,
The other rotating body includes a metal core material and a clamping body that sandwiches the sheet material with the one rotating body, and the clamping body is formed on a part of the surface of the core material. Thus , the sheet material transporting apparatus is configured such that the core material is exposed to the transport path in a portion other than the position where the sandwiched body is formed . In the sheet material conveying machine according to claim 1,
Each rotating body is disposed above the vicinity of the fixing device, and the other rotating body is disposed above the fixing roller for heating among the pair of rollers constituting the fixing device. Carrier machine. In the sheet material conveying machine according to claim 2 ,
The one rotating body includes a sandwiching body that is formed with a larger diameter than the core material and sandwiches the sheet material with the sandwiching body of the other rotating body , and the sandwiching body and the covering material are made of the same material. A sheet material conveying machine characterized by being integrally formed. In the sheet material conveying machine according to any one of claims 1 to 3 ,
The conveyance path is freely open so that a sheet material stagnating in the middle of the path can be taken out, and the one rotating body is exposed to the space side where the user inserts a hand by opening the conveyance path. A sheet material conveying machine characterized by the above-mentioned structure . In the sheet material conveyance machine according to any one of claims 1 to 4 ,
A sheet material transporting machine, wherein the covering material is made of a material having heat resistance. In the sheet material conveying machine according to any one of claims 1 to 5 ,
An outer surface of the covering material is formed in such a shape that its surface area is enlarged.

Images