JP3842265B2 - Release agent coating mechanism, fixing device and printing device - Google Patents

Description

  The present invention relates to a release agent application mechanism that applies a release agent such as oil to a fixing roller of a printing apparatus.

Usually, a printing apparatus such as a copying machine or a printer includes a fixing device for fixing a toner image transferred to a printing paper.
Such a fixing device normally performs image fixing by thermocompression bonding of a printing sheet onto which an image has been transferred with a fixing roller (roller pair).

By the way, in such a fixing device, a release agent such as silicone oil is supplied (applied) to the surface of the fixing roller. This is to prevent image transfer (image offset) to the fixing roller and wrapping of printing paper around the fixing roller in order to stably perform image fixing.
Such application of oil is described in Patent Documents 1-6.

6 and 7 are explanatory diagrams showing conventional oil application techniques for the fixing roller described in Patent Documents 2 to 5. FIG.
As shown in these drawings, conventionally, a tubular member 105 is supplied from an oil tank 104 that can inject oil from the outside and always stores oil by a piezo-type pump (or electromagnetic pump) 103 on the upper part thereof. Oil is sucked up and supplied to the pipe member 101.

  A plurality of holes (oil discharge holes) are provided in the upper part of the pipe member 101 along the longitudinal direction thereof. Further, a felt 106 and a felt (felt for supplying a release agent) 106 for receiving oil raining down from the pipe member 101 are applied to a fixing roller (applied member) 102 below the pipe member 101. An application roller 107 is provided for this purpose.

  In addition, processing (for example, caulking processing (processing for crushing the tip with a press or the like)) for preventing oil from leaking is performed on the most downstream side (tip portion) of the pipe member 101. Oil spill from the

  Further, the excess oil remaining on the felt 106 without being applied to the fixing roller 102 is collected by a dish-shaped oil pan (release agent receiving tray) 108 formed in the lower part thereof. Then, it is returned to the oil tank 104 by a tubular member 109 connected to the oil pan 108.

A sensor 110 that detects the remaining amount of oil is installed in the oil tank 104. The sensor 110 detects the remaining amount of oil in the tank and transmits the detection result to the control unit of the printing apparatus.
As a result, when the remaining amount of oil is low, a display for prompting oil replenishment is displayed on a display panel or the like provided in the printing apparatus main body, or the printing apparatus is temporarily disabled.

  Note that when the oil supply is partially insufficient in the longitudinal direction of the fixing roller 102, the above-described image offset and printing paper wrapping occur. Accordingly, it is very important to supply the oil uniformly (balance the supply amount) in the longitudinal direction of the fixing roller 102.

  For this reason, in the above-described prior art, a plurality of holes are formed in the pipe member 101 upward (upward). Accordingly, it is possible to simultaneously discharge oil from all the holes in a state where the printing apparatus is installed horizontally (normal state).

Further, in the conventional technology as described above, only the felt and the application roller are provided as an intermediate member provided between the pipe and the fixing roller for diffusing oil in the longitudinal direction.
Therefore, when the viscosity of the oil is relatively high, the oil cannot be sufficiently diffused and may not be uniformly applied in the longitudinal direction.
For this reason, in the techniques of Patent Documents 2 and 3, a guide member is provided on the pipe member 101 so as to achieve uniformity.
JP-A-8-137317 (issue date; May 31, 1996) JP 2002-278345 A (issue date: September 27, 2002) JP 2003-122167 A (issue date; April 25, 2003)

  However, in the conventional technique using a guide member for diffusing oil, the guide member is provided in a portion near the application roller that is in contact with the fixing roller. For this reason, there is a possibility that the oil passing through the guide member is deteriorated by heat generated from the application roller.

  The present invention has been made in view of the conventional problems as described above. And the objective is to provide the release agent application | coating mechanism which can prevent deterioration of the release agent by a heat | fever.

  A release agent application mechanism (main application mechanism) of the present invention is a release agent application mechanism for applying a release agent to a fixing roller of a printing apparatus, and a plurality of holes formed in a pipe extending along the fixing roller. In the release agent application mechanism for supplying the release agent discharged from the pipe via the release agent guide to the release agent application roller that rotates while discharging the release agent from the release roller and in contact with the fixing roller, The release agent application roller is provided with an application member for applying the release agent from the lower side, the pipe is arranged above the release agent application roller, and the release agent guide is connected to the pipe. It is designed to supply the release agent discharged from the application member to the application member. Further, a part of the release agent guide is away from the release agent application roller with respect to the vertical line passing through the center of the pipe. It is characterized by swelling.

  Further, in the mold release agent guide having the above-described shape, after the lower end portion of the mold release agent guide is fixed to the application member, the mold release agent guide is separated from the mold release agent application roller from the fixed position more than the vertical line. It can be constructed by extending in the direction once, further folding back toward the release agent application roller side with respect to the perpendicular, and contacting the lower part of the pipe.

In this configuration, it is preferable that the release agent guide is provided with a slit extending from the fixed lower end portion toward the contact point with the pipe.
Further, it is preferable that the slit extends beyond the contact point with the pipe on the release agent guide.
Further, the release agent guide is preferably in contact with the pipe in an inclined state with the side closer to the application member lowered.
Moreover, it is preferable to form more slits of the release agent guide than the holes of the pipe.

The release agent guide is preferably in contact with the pipe by its own elastic force.
In this application mechanism, it is preferable that the release agent guide is made of a material having a release agent resistance.

The fixing device of the present invention includes the above-described coating mechanism.
Further, the printing apparatus of the present invention has a fixing device provided with the present application mechanism.

  A release agent application mechanism (main application mechanism) of the present invention is a release agent application mechanism for applying a release agent to a fixing roller of a printing apparatus, and a plurality of holes formed in a pipe extending along the fixing roller. In the release agent application mechanism for supplying the release agent discharged from the pipe via the release agent guide to the release agent application roller that rotates while discharging the release agent from the release roller and in contact with the fixing roller, The release agent application roller is provided with an application member for applying the release agent from the lower side, the pipe is arranged above the release agent application roller, and the release agent guide is connected to the pipe. It is designed to supply the release agent discharged from the application member to the application member. Further, a part of the release agent guide is away from the release agent application roller with respect to the vertical line passing through the center of the pipe. It is characterized by swelling.

This application mechanism applies a release agent to a fixing roller in a printing apparatus such as a copying machine or a printer.
Here, the fixing roller is a roller for fixing the image on the paper by pressing the printing paper on which the image is transferred.
The release agent is applied to the fixing roller in order to prevent image transfer (image offset) to the fixing roller and wrapping of printing paper around the fixing roller. As such a release agent, for example, silicone oil can be used.

  Further, as described above, the present application mechanism has a hollow pipe extending along the fixing roller. This pipe discharges the release agent from a plurality of holes formed in itself.

Further, the present application mechanism includes a release agent application roller.
The release agent application roller is disposed below the pipe, is disposed along the fixing roller, and rotates while being in contact with the fixing roller. The release agent application roller has a function of applying the release agent discharged from the pipe and supplied to the fixing roller to the fixing roller.

Further, the present application mechanism includes a release agent guide (guide member) and an application member in order to supply the release agent discharged from the pipe to the release agent application roller.
This application member applies the release agent from below to the release agent application roller.
The release agent guide is for supplying the release agent discharged from the pipe to the application member.

  That is, in the present application mechanism, the pipe disposed on the upper side of the release agent application roller and the application member disposed on the lower side of the release agent application roller are connected by the release agent guide. And this guide carries a mold release agent from a pipe to an application member.

The upper side and the lower side described above are positions in the vertical direction, and do not indicate positions in the horizontal direction. Therefore, the positions of the pipe, the release agent application roller, and the application member in the horizontal direction may be different from each other.
Further, “lower side (upper side) than the release agent application roller” refers to a region lower (upper side) than the center of the release agent application roller.

In particular, in the present application mechanism, a part of the release agent guide swells away from the release agent application roller with respect to the vertical line passing through the center of the pipe (so as to be separated from the release agent application roller). Curved shape).
Here, the perpendicular passing through the center of the pipe is an imaginary straight line extending downward from the center of the pipe in the vertical direction.
That is, in this application mechanism, a part of the release agent guide is shaped to avoid the high temperature release agent application roller (to bypass the release agent application roller).

Thereby, in this application | coating mechanism, it becomes possible to keep the release agent which propagates a release agent guide away from a high temperature release agent application roller.
Therefore, in this application mechanism, it is possible to suppress the deterioration of the release agent on the release agent guide due to the heat of the application roller.
Further, by providing the fixing mechanism of the printing apparatus with the present application mechanism, it is possible to realize a fixing apparatus that can suppress deterioration of the release agent due to heat.

Further, in the mold release agent guide having the above-described shape, after the lower end portion of the mold release agent guide is fixed to the application member, the mold release agent guide is separated from the mold release agent application roller from the fixed position more than the vertical line. It can be constructed by extending in the direction once, further folding back toward the release agent application roller side with respect to the perpendicular, and contacting the lower part of the pipe.
In this configuration, the release agent guide is brought into contact with the pipe. For this reason, the release agent discharged from the pipe is diffused in the longitudinal direction of the pipe (the direction in which the pipe extends) by surface tension at the contact (tangent) between the pipe and the release agent guide, and then conveyed to the coating member. It becomes possible.

  Therefore, the release agent discharged from the pipe can be uniformly supplied to the application member (and the release agent application roller) over its entire length (entire). As a result, it is possible to apply the release agent to the entire area of the fixing roller extremely uniformly (balance the coating amount).

In this configuration, it is preferable that the release agent guide is provided with a slit extending from the fixed lower end portion toward the contact point with the pipe.
Thereby, the mold release agent discharged | emitted from the pipe can be transmitted also to the back surface side of a mold release agent guide through a slit. Therefore, the release agent can be supplied to the application member using both surfaces of the release agent guide, and the supply rate of the release agent can be improved.
In this configuration, the release agent flows through a portion of the release agent guide where there is no slit (between the slits; a guide portion).

Further, it is preferable that the slit extends beyond the contact point with the pipe on the release agent guide.
That is, the release agent discharged from the pipe falls through the pipe outer wall on both sides of the above-described normal passing through the center of the pipe, and is received by the release agent guide on both sides of the contact point between the pipe and the release agent guide. .

Here, both sides of the contact point between the pipe and the release agent guide are the side close to the application member in the release agent guide and the side beyond the contact point as viewed from the application member (the side far from the application member). is there. Note that “close (far) to the coating member” is the closeness (distance) on the path along the release agent guide from the pipe to the coating member, and is not related to the actual distance. is there.
And the mold release agent which fell to the side near the application member in the mold release agent guide reaches the application member through the mold release agent guide as it is.
On the other hand, the release agent that has fallen to the side far from the application member does not flow to the application member as it is because there is a contact point between the pipe and the release agent guide in the path to the application member.
Therefore, by providing a slit in the release agent guide so as to exceed the contact point with the pipe, the release agent that has fallen to the side far from the application member is allowed to escape to the back surface of the release agent guide through the slit. It becomes possible to supply to the application member via the back surface. Thereby, it can avoid that oil accumulates between a mold release agent guide and a pipe.

Further, the release agent guide is preferably in contact with the pipe in an inclined state with the side closer to the application member lowered.
Here, the inclined state is, of course, a state that is not a horizontal state or a state of standing in the vertical (vertical) direction.

In this configuration, the release agent guide is raised from the side closer to the application member toward the far side with the contact with the pipe interposed therebetween.
As a result, the oil received by the release agent guide on the side close to the application member can flow directly to the application member. On the other hand, it can be avoided that the oil received on the side far from the application member flows in a direction far from the application member (a direction away from the application member on the release agent guide).

Moreover, it is preferable to form more slits of the release agent guide than the holes of the pipe.
The release agent flowing through the release agent guide is difficult to move so as to cross the slit. For this reason, if a large number of slits are formed, the release agent diffused in the longitudinal direction due to the surface tension between the pipe and the release agent guide can reach the application member while maintaining its diffusion state. Become.

  The release agent guide is preferably in contact with the pipe by its own elastic force. In this configuration, it is not necessary to attach the release agent guide to the pipe using an adhesive or the like. For this reason, it becomes easy to assemble this application mechanism.

Moreover, it is also possible to avoid that the diffusibility (uniform supply property) of the release agent is partially impaired due to the variation in the bonding part (mixed parts that are bonded and not). If there is no part, the diffusivity will fall).
Further, it is possible to prevent the release agent guide from being peeled off from the pipe due to a decrease in adhesive force during use of the present application mechanism. Furthermore, it is easy to replace the release agent guide.

In this application mechanism, it is preferable that the release agent guide is made of a material having a release agent resistance.
Here, the material having mold release resistance is a material that can avoid the penetration of the release agent (a material that does not penetrate the release agent).

  In this configuration, it is possible to prevent the release agent from being soaked into the release agent guide. For this reason, the speed at which the release agent is fed into the application member can be increased by the release agent guide. Therefore, since the time for which the release agent is on the release agent guide can be shortened, deterioration of the release agent due to heat can be further suppressed.

  Further, when using a release agent guide of a type in which the release agent is soaked, the release agent cannot be transmitted to the application member unless the release agent guide is soaked with a sufficient amount of the release agent. For this reason, a large amount of release agent is required at the start of use of the present application mechanism (at the time of preparation for use), and it takes time to prepare for use.

  On the other hand, if a release agent guide having a release agent resistance is used, it is not necessary to soak the release agent into the release agent guide. For this reason, while being able to reduce the amount of mold release agents required for use preparation, the time for use preparation can be shortened significantly.

An embodiment of the present invention will be described.
FIG. 2 is an explanatory diagram showing the configuration of the copying machine 1, which is a digital color copying machine according to the present embodiment. The copying machine 1 has a function as a facsimile machine and a printer in addition to a function as a normal copying machine.

  First, the configuration of the copying machine 1 will be described. As shown in FIG. 2, the copying machine 1 has a configuration in which a RADF 112, a scanner unit 110, an image forming unit 210, and a paper feeding mechanism 211 are provided, and further includes an operation panel (not shown).

  The RADF 112 is a document feeding device in the copying machine 1 and has a function as a double-sided automatic document feeding device (RADF).

That is, the RADF 112 conveys a document set at a predetermined position onto a document table 111 in the scanner unit 110. Then, after the document image is read by the scanner unit 110, it has a function of carrying it out to a predetermined take-out position.
The RADF 112 also has a function of turning over the original after reading the original image by the scanner unit 110 and transporting the original to the original table 111 again. As a result, the copying machine 1 can cause the scanner unit 110 to read images on both sides of the document.

  Further, the RADF 112 can be opened and closed with respect to the document table 111. Therefore, when using the RADF 112, the user can place the document directly on the document table 111 by closing the RADF 112 and opening the RADF 112.

  The scanner unit 110 is for reading an image of a document conveyed by the RADF 112 and is an image input device in the copying machine 1. As shown in FIG. 2, the scanner unit 110 includes a first scanning unit 113, a second scanning unit 114, an optical lens 115, and a CCD 116 in addition to the document table 111 described above.

The scanning units 113 and 114 are for reading an image of a document placed on the document table 111 by reciprocating in parallel with the document table 111.
The first scanning unit 113 includes an exposure lamp that exposes a document image and a first mirror that deflects a reflected light image from the document in a predetermined direction. Then, it is set so as to reciprocate in parallel with the document table 111 at a predetermined scanning speed while maintaining a certain distance from the lower surface of the document table 111.

  The second scanning unit 114 includes second and third mirrors for deflecting the reflected light image deflected by the first mirror in the direction in which the optical lens 115 is positioned. The first scanning unit 113 reciprocates in parallel with the document table 111 while maintaining a constant speed relationship.

  The optical lens 115 reduces the reflected light image from the original deflected by the first to third mirrors and forms an image at a predetermined position on the CCD 116.

  A CCD (Charge Coupled Device) 116 is a photoelectric conversion element (line sensor) for photoelectrically converting the formed reflected light image to generate image information of an electrical signal and outputting it to the image forming unit 210.

  Further, the CCD 116 can read a color image. That is, the CCD 116 can generate image information of line data color-separated for each color component of R (red), G (green), and B (blue) from the color reflected light image.

  The image information generated by the CCD 116 is further transferred to an image processing unit (not shown), subjected to predetermined image processing, and then output to the image forming unit 210.

  The image forming unit 210 is for printing an image on printing paper based on the image information output from the CCD 116. The image forming unit 210 includes a black image transfer unit 301, a yellow image transfer unit 302, a magenta image transfer unit 303, and a cyan image transfer unit 304, as shown in FIG.

  These transfer units 301 to 304 have substantially the same configuration, and are set to transfer a black image, a yellow image, a magenta image, and a cyan image, respectively, to the printing paper based on the image information. ing.

  As shown in FIG. 2, these transfer units 301 to 304 have LSUs 227a to 227d and image forming stations Pa to Pd, respectively.

  Pixel signals corresponding to a black component, a yellow component, a magenta component, and a cyan component in image information are input to LSUs (laser beam scanner units) 227a to 227d, respectively. Each of the LSUs 227a to 227d is set so as to expose photosensitive drums 222a to 222d (to be described later) in the image forming stations Pa to Pd based on these image signals to generate an electrostatic latent image.

  The LSUs 227a to 227d include a semiconductor laser diode (not shown) and a laser control unit that controls the power of the semiconductor laser diode and the light generation timing in order to generate a dot-shaped laser beam modulated according to image information. And have.

  Further, as shown in FIG. 2, the LSUs 227a to 227d include polygon mirrors 240a to 240d, f-θ lenses 241a to 241d, and mirrors 242a to 242d and 243a to 243d.

  The polygon mirrors 240a to 240d have a function of deflecting a laser beam emitted from the semiconductor laser element in the main scanning direction. The f-θ lenses and mirrors described above are for imaging the laser beams deflected by the polygon mirrors 240a to 240d on the surfaces of the photosensitive drums 222a to 222d.

The image forming stations Pa to Pd generate toner images corresponding to the respective colors based on the laser beams emitted from the LSUs 227a to 227d, and sequentially transfer the toner images to the printing paper.
As shown in FIG. 2, these image forming stations Pa to Pd include photosensitive drums 222a to 222d, and further, chargers 223a to 223d, developing devices 224a to 224d, transfer dischargers 225a to 225d, and cleaning. Devices 226a to 226d are arranged around the photosensitive drums 222a to 222d along the direction of arrow F.

  Each of the photosensitive drums (transfer drums) 222a to 222d is a drum-shaped transfer roller having a photosensitive material on its surface, and is set to be rotationally driven in the direction of arrow F. The chargers 223a to 223d are for uniformly charging the photosensitive drums 222a to 222d, respectively.

  The developing devices 224a to 224d contain black, yellow, magenta, and cyan toners, respectively. These toners have a function of developing the electrostatic latent images generated on the photosensitive drums 222a to 222d to generate toner images.

The transfer dischargers 225a to 225d are dischargers for transferring the toner images on the photosensitive drums 222a to 222d to a printing sheet. The power (potential) of these transfer dischargers 225a to 225d is controlled by a power control unit (not shown).
Further, the cleaning devices 226a to 226d shown in FIG. 2 have a function of removing toner remaining on the photosensitive drums 222a to 222d after transfer onto the printing paper.

  The paper feed mechanism 211 conveys the printing paper to a predetermined position of the image forming unit 210 in order to transfer the color toner images generated by the image forming unit 210 onto the printing paper. Further, the paper feed mechanism 211 has a function of discharging the printing paper to the outside after the toner image is transferred.

  As shown in FIG. 2, the paper feed mechanism 211 includes a printing paper cassette 251, a take-out roller 253, a plurality of transport rollers 252, 261, a registration roller 212, a transfer transport belt mechanism 213, a fixing device 217, a transport direction switching gate 218, A paper discharge roller 219 and a paper discharge tray 220 are provided.

The printing paper cassette 251 is for storing printing paper P in the form of cut printing paper used in the copying machine 1.
The take-out roller 252 is a pickup roller for taking out the printing paper P from the printing paper cassette 251 one by one.
Further, the transport rollers 252... Feed the print paper P output from the print paper cassette 251 to the main transport path L and transport it on the transport path L.

  The pre-registration detection switch is for detecting that the printing paper P transported by the transport rollers 252... Has passed a predetermined position on the main transport path L and outputting a predetermined detection signal.

  The registration roller 212 temporarily holds the printing paper P that has been transported along the main transport path L. The toner image on the photoconductive drums 222a to 222d has a function of feeding it to the transfer / conveying belt mechanism 213 at the timing of each image forming station Pa to Pd so that the toner image can be satisfactorily transferred to the printing paper P. .

  That is, the registration roller 212 prints the printing paper P so that the leading edge of the toner image on the photosensitive drums 222a to 222d is pressed against the leading edge of the printing range on the printing paper P based on the detection signal output from the pre-registration detection switch. Is set to be fed into the transfer conveyance belt mechanism 213.

  As shown in FIG. 2, the transfer / conveying belt mechanism 213 includes a driving roller 214, a driven roller 215, a conveying belt 216, and an auxiliary roller 231.

  The conveyor belt 216 is a belt that is placed between the driving roller 214 and the driven roller 215, and is frictionally driven in the direction of arrow Z by the rollers 214 and 215. The printing paper P fed by the registration rollers 212 is electrostatically attracted and transported to the image forming stations Pa to Pd and the fixing device 217.

  That is, each color toner image is transferred and superimposed on the printing paper P conveyed to the image forming stations Pa to Pd. When the transfer by the image forming station Pd is completed, the printing paper P is set to be sequentially peeled off from the conveying belt 216 from the leading end portion thereof by the static eliminator 229 and guided to the fixing device 217.

The fixing device 217 heat-fixes the unfixed toner image transferred to the printing paper P. Then, the heat-fixed printing paper P is conveyed to the conveyance direction switching gate 218.
The fixing device 217 will be described later in detail.

The switching gate 218 selectively switches the transport path of the printing paper P after fixing between a discharge path toward the discharge tray 220 and the sub-transport path S.
The sub-transport path S is a transport path for turning over the printing paper P and re-supplying it to the image forming unit 210.
That is, the printing paper P sent to the sub-transport path S is turned over through the switchback transport path 221 and then transported on the sub-transport path S by the transport rollers 261. It is set to be supplied again.

Next, the fixing device 217 which is a characteristic configuration of the copying machine 1 will be described in detail.
FIG. 3 is a perspective view showing the configuration of the fixing device 217. FIG. 4 is a front view showing the configuration of the fixing device 217.
As shown in these drawings, the fixing device 217 includes a fixing roller pair including a fixing roller (upper fixing roller) 11 and a pressure roller (lower fixing roller) 12.

These rollers 11 and 12 are arranged so as to be in pressure contact with each other, both of which have rubber layers 11b and 12b made of silicone rubber on the aluminum cores 11a and 12a, and inside the cores The heaters 11c and 12c including halogen lamps are provided.
The fixing roller 11 and the pressure roller 12 both heat and press the sheet, but are given different names for convenience.

  Further, a peeling claw 13, a cleaning roller 14, and a roller temperature detector 15 are disposed around the rollers 11 and 12, respectively. Further, the fixing roller 11 is provided with an oil application roller 16.

The peeling claw 13 peels off the printing paper (recording material) wound around the rollers 11 and 12 from the surface of the rollers 11 and 12.
The cleaning roller 14 is a roller having a felt surface. The cleaning roller 14 is in sliding contact with the rollers 11 and 12 and collects offset toner attached to the surfaces of the rollers 11 and 12.
Here, the offset toner is toner that has moved to the rollers 11 and 12 from the toner image transferred to the printing paper for fixing.

  The roller temperature detector 15 is formed of a thermistor and is in contact with the surfaces of the rollers 11 and 12 to detect the temperature. The temperature detected by the roller temperature detector 15 is sent to a fixing control unit (not shown) provided in the fixing device 217.

This fixing controller controls the output of the power supply unit (not shown) of the heaters 11c and 12c based on the detection results of the two roller temperature detectors 15 provided in the rollers 11 and 12.
As a result, the fixing controller switches the heaters 11c and 12c of the rollers 11 and 12 on and off to adjust the surface temperatures of the rollers 11 and 12.

Next, the oil application mechanism (main application mechanism) provided in the fixing device 217 will be described.
The present application mechanism is provided on the side and lower portions of the rollers 11 and 12, and is for uniformly applying silicone oil (release agent; hereinafter referred to as oil) to the surface of the fixing roller 11. .
The oil used in this coating mechanism has a dimethylpolysiloxane structure and a kinematic viscosity at 25 ° C. of 100 cs.

  As shown in FIG. 4, in addition to the oil application roller 16, the present application mechanism includes an oil tank 21, a pump 22, a tube member 23, a pipe portion 24, a felt 25, an oil pan 26, a tube member 27, an oil sensor. 28 and a blade 29 are provided.

The oil tank 21 is a tank that stores silicone oil, and includes an oil supply port 21a for receiving oil supply from the outside.
The pump 22 sucks up the oil in the oil tank 21 and can be constituted by a piezo pump or an electromagnetic pump.

The tube member 23 is a line that supplies oil sucked from the pump 22 to the pipe portion 24.
The pipe portion 24 is a hollow having substantially the same length as the fixing roller 11 extending along the fixing roller 11 (and the oil application roller 16) along the longitudinal direction of the fixing roller 11 (direction perpendicular to the paper surface of FIG. 4). Pipe (described later).
And the pipe part 24 has a function which supplies the felt 25 with the oil supplied to this pipe from the whole area of the full length.

  The felt (applying member) 25 extends along the longitudinal direction of the fixing roller 11 below the oil applying roller 16 and extends alongside the fixing roller 11 (and the oil applying roller 16). It is a plate-like felt. Further, the surface of the felt 25 is slightly inclined on the lower side of the oil application roller 16 and is designed to contact the oil application roller 16.

  And the felt 25 has the function (function as an oil supply felt) which makes the oil supplied from the pipe part 24 soak into the whole surface, and supplies it to the whole surface of the oil application roller 16 mentioned later.

The felt 25 is arranged on an elastic felt base (applying member) 25a made of a metal (a stainless steel plate having a thickness of 0.2 mm) slightly larger than itself. The felt 25 is in elastic contact with the oil application roller 16 (biased by the oil application roller 16) by the elastic force of the felt base 25a.
Further, the felt base 25 a is fixed to a sheet metal 300 provided in the casing of the fixing device 217 (or the casing of the copying machine 1) below the center of the oil application roller 16.

The oil application roller 16 (release agent application roller) has a rubber surface, is in contact with the fixing roller 11, and extends in parallel with the fixing roller 11 and has substantially the same length as the fixing roller 11. It is Sano Roller.
The oil application roller 16 has a function of applying oil supplied from the felt 25 to the surface of the fixing roller 11 by rotating following the fixing roller 11.

  A blade 29 shown in FIG. 4 is a rubber-like member for uniformly extending the oil supplied to the oil application roller 16 to the surface of the roller 16 (in the form of a thin film). 29 is omitted).

A part of the oil supplied to the felt 25 falls from the felt 25 without being supplied to the oil application roller 16.
The oil pan 26 is a dish-shaped member for receiving such oil (surplus oil) that has fallen from the felt 25.
The oil received in the oil pan 26 is returned to the oil tank 21 by the tube member 27.

  The oil sensor 28 is a sensor that is provided in the oil tank 21 and detects the remaining amount of oil in the tank 21. That is, the sensor 28 detects the remaining amount of oil in the tank 21 and transmits the detection result to the fixing control unit of the fixing device 217.

As a result, when the remaining amount of oil is low, a display prompting oil supply is displayed on a display panel or the like provided in the copying machine 1, or the copying machine 1 is temporarily disabled.
When the oil sensor 28 detects that a sufficient amount of oil has been injected into the oil tank 21, the oil sensor 28 transmits the detection result to the fixing control unit. As a result, the display or print disabled state is eliminated.

Next, the structure of the pipe part 24 is demonstrated.
FIG. 1 is a cross-sectional view showing a configuration of the pipe portion 24, and FIG. 5 is a development view (a diagram expressing the guide sheet 33 in a plan view).
As shown in these drawings, the pipe portion 24 is composed of a pipe 31 and a guide sheet 33.

The pipe 31 is a hollow member having a plurality of holes 41 provided at predetermined intervals and disposed above the oil application roller 16.
The holes 41 are arranged side by side in the upper part (top) of the pipe 31 and are for discharging oil supplied to the pipe 31.

Further, one end of the pipe 31 is connected to the tube member 23 described above, and is supplied with oil.
Further, the other end (downstream) of the pipe 31 is subjected to a caulking process (a process of crushing the tip with a press or the like) so as not to leak oil.
Accordingly, all the oil supplied to the pipe 31 is discharged from the hole 41.

  The guide sheet (release agent guide, guide member) 33 is a rectangular resin sheet (PET (polyethylene terephthalate) having a thickness of 0.1 mm), which is continuously provided at the upper end 51, the intermediate portion 52, and the lower end 53. is there. That is, the guide sheet 33 has a configuration in which an upper end portion 51 and a lower end portion 53 are provided at both ends of the intermediate portion 52.

Here, the sheet is a thin plate made of a resin capable of allowing the release agent to flow down on the surface or inside.
The guide sheet 33 is provided below the oil application roller 16 by allowing the oil discharged from the hole 41 of the pipe 31 located above the oil application roller 16 to pass through the side of the oil application roller 16. For guiding (carrying) toward the felt 25.

As shown in FIG. 1, the guide sheet 33 is in a state where the upper end portion 51 is disposed on the pipe 31 side and the lower end portion 53 is disposed on the felt 25 side.
Further, in the guide sheet 33, most of the intermediate portion 52 is swollen (curved) in a direction away from the oil application roller 16 with respect to the vertical line S extending in the vertical direction from the center of the pipe 31 (center of the hole 41). It has become.

That is, in the guide sheet 33, the sheet metal 300 is arranged such that the lower end 53 sandwiches the felt base 25 a together with the sheet metal 300 on the lower side than the center of the oil application roller 16 (and on the oil application roller 16 side from the perpendicular S). (In the screwed portion, the sheet metal 300, the felt base 25a, and the lower end portion 53 are laminated in this order. The lower end portion 53 includes the oil application roller 16 (felt). 25).
Further, the end portion of the felt base 25 a is set so as to overlap the intermediate portion 52 beyond the lower end portion 53.

Further, the intermediate portion 52 has a shape that extends in a direction away from the oil application roller 16 beyond the perpendicular S and then folded back toward the oil application roller 16. The intermediate portion 52 is configured to elastically contact the pipe 31 formed on the upper side of the oil application roller 16 from the oblique lower side in the region closer to the oil application roller 16 than the perpendicular S.
That is, the guide sheet 33 is in contact with the pipe 31 in an inclined state with the side closer to the felt 25 lowered.
Note that “close to (distant from) the felt 25” is the closeness (distant) on the path along the guide sheet 33 from the pipe 31 to the felt 25, and is not related to the actual distance. is there.

Further, the contact point C between the intermediate portion 52 and the pipe 31 is closer to the oil application roller 16 than the normal S. The intermediate portion 52 is in contact with the pipe 31 at the contact point C in an inclined state as described above.
In the present application mechanism, the upper end portion 51 of the guide sheet 33 is disposed so as to avoid contact with the pipe 31.

Further, as shown in FIG. 5, a plurality of slits 61 are formed in the intermediate portion 52 of the guide sheet 33 at predetermined intervals.
The plurality of slits 61 are gaps (openings) having a width of 4 mm provided in parallel to each other along the direction in which the intermediate portion 52 extends (the direction from the lower end portion 53 toward the contact point with the pipe 31). A space between the two slits 61 and 61 serves as a guide portion 62 for guiding oil.
The guide portion 62 also has a width of 4 mm like the slit 61.
Further, the upper end 51 and the lower end 53 are not provided with such a slit 61, and are in a flush state (the portion having the slit 61 in the guide sheet 33 is the intermediate portion 52, and the both ends thereof The portion without the slit 61 is the end portions 51 and 53).

As shown in FIGS. 1 and 5, an oil discharge port 71 is provided between a portion where the felt 25 is placed on the felt base 25 a and a portion sandwiched between the lower end portion 53 of the guide sheet 33 and the sheet metal 300. Is provided.
The oil discharge port 71 is for discharging excess oil to the oil pan 26.

Next, an oil application operation to the fixing roller 11 by the present application mechanism will be described.
In the oil application to the fixing roller 11, first, the pump 22 sucks up the oil in the oil tank 21 and supplies it to the pipe portion 24 via the tube member 23.
The oil supplied to the pipe portion 24 is stored in the pipe 31 and discharged from the hole 41 when the capacity in the pipe 31 is exceeded.

The oil discharged from the hole 41 falls through the outer wall of the pipe 31 and is received by the surface of the intermediate portion 52 (the surface facing the pipe 31) of the guide sheet 33. The oil received on the surface of the intermediate part 52 is diffused in the longitudinal direction of the pipe 31 by the surface tension between the surface of the intermediate part 52 and the outer wall of the pipe 31.
Thereafter, the oil also enters the back surface (surface on the oil application roller 16 side) of the intermediate portion 52 through the slit 61. Then, it flows on the back surface and the front surface (on the guide portion 62) of the intermediate portion 52 swelled in the direction away from the oil application roller 16 with respect to the perpendicular S, and reaches the lower end portion 53.

Here, the oil flowing on the back surface of the intermediate portion 52 flows on the lower end portion 53 as it is to reach the felt 25.
On the other hand, the oil that has flowed on the surface of the intermediate portion 52 reaches the felt base 25a protruding from the lower end portion 53 toward the intermediate portion 52 side below the guide sheet 33. After that, it enters the back surface of the intermediate portion 52 through the slit 61 (floats), and reaches the felt 25 through the lower end portion 53.

Thereafter, the oil is impregnated with the felt 25 and applied to the surface of the fixing roller 11 via the oil application roller 16.
Here, the oil transmitted from the felt 25 to the oil application roller 16 and supplied to the fixing roller 11 is about 10% of the oil reaching the felt 25. The remaining 90% of the oil overflows from the felt 25 and is discharged to the oil pan 26 from the end of the felt 25 (the end on the oil application roller 16 side) and the oil discharge port 71.

As described above, in the present application mechanism, a part of the guide sheet 33 swells away from the oil application roller 16 with respect to the perpendicular S passing through the center of the pipe 31 (so as to be separated from the oil application roller 16). Curved shape).
That is, in the present application mechanism, a part of the guide sheet 33 is shaped to avoid the high temperature oil application roller 16 (to bypass the oil application roller 16).

Thereby, in this application | coating mechanism, it becomes possible to keep the oil which conveys the guide sheet 33 away from the hot oil application roller 16. FIG.
Therefore, in this application mechanism, it is possible to suppress the oil flowing through the guide sheet 33 from being deteriorated by the heat of the application roller.

Note that the surface temperature of the fixing roller 11 for heating the printing paper is controlled to be 180 ° C. in a normal state where the temperature control is normally performed (when trouble occurs, it may reach about 200 ° C.).
The oil application roller 16 in contact with the fixing roller 11 has a surface temperature of about 150 ° C.

On the other hand, the ambient temperature in the vicinity of the pipe 31 is normally about 100 ° C., which is significantly lower than the temperature of the oil application roller 16.
Therefore, in the present application mechanism, the guide sheet 33 is shaped so as to bypass the oil application roller 16, so that the temperature at which the oil is exposed to the felt 25 from the guide sheet 33 can be maintained at about 100 ° C. It has become.

  In this application mechanism, after the lower end 53 of the guide sheet 33 is fixed to the felt base 25a (sheet metal 300), the guide sheet 33 is once extended from the fixed position in a direction away from the oil application roller 16 from the perpendicular S. Furthermore, it is configured such that it is folded back to the oil application roller 16 side from the vertical line S and brought into contact with the lower part of the pipe 31.

  That is, in this coating mechanism, the guide sheet 33 is brought into contact with the pipe 31. For this reason, the oil discharged from the pipe 31 is diffused in the longitudinal direction of the pipe 31 (the direction in which the pipe 31 extends) by the surface tension at the contact (tangent) between the pipe 31 and the guide sheet 33, and then the felt 25 It can be carried.

  Therefore, the oil discharged from the pipe 31 can be uniformly supplied to the felt 25 (and the oil application roller 16) over its entire length (entire). As a result, it is possible to apply the oil to the entire area of the fixing roller 11 in an extremely uniform manner (to balance the amount of application).

In this configuration, the guide sheet 33 is provided with a slit 61 extending from the fixed lower end 53 toward the contact point with the pipe 31.
Thereby, the oil discharged from the pipe 31 can be transmitted to the back side of the guide sheet 33 through the slit 61. Therefore, oil can be supplied to the felt 25 using both surfaces of the guide sheet 33. For this reason, the supply speed of oil can be improved.

Moreover, in this application | coating mechanism, while arrange | positioning the intermediate part 52 of the guide sheet 33 with the pipe 31, it arrange | positions so that the upper end part 51 may avoid contacting the pipe 31. FIG.
This is because when the pipe 31 and the upper end 51 without the slit 61 are in contact, the oil overflowing from the hole 41 to the oil application roller 16 side (the side far from the felt 25) This is because they accumulate in the middle and spill out from both ends in the longitudinal direction.

  That is, when the intermediate portion 52 and the pipe 31 are in contact with each other, the oil overflowing from the hole 41 to the oil application roller 16 side is drained to the back surface side through the slit 61 of the intermediate portion 52, and the guide portion 62. Can be conveyed to felt 25.

Further, in the present application mechanism, the guide sheet 33 is in contact with the pipe 31 in an inclined state with the side closer to the felt 25 lowered.
In this configuration, the guide sheet 33 is in a state of rising from the side closer to the felt 25 toward the far side with the contact C with the pipe 31 interposed therebetween.
Thereby, the oil received by the guide sheet 33 on the side close to the felt 25 can be allowed to flow through the felt 25 as it is. On the other hand, it is possible to prevent the oil received on the side far from the felt 25 from flowing in a direction far from the felt 25 (a direction away from the felt 25 on the guide sheet 33).

  Further, in the present application mechanism, the guide sheet 33 is brought into contact with the pipe 31 by the elastic force of the sheet itself. Therefore, it is not necessary to stick the guide sheet 33 to the pipe 31 using an adhesive or the like. For this reason, it becomes easy to assemble this application mechanism.

Moreover, it is also possible to avoid that the diffusibility (uniform supply property) of the oil is partially impaired due to the variation in the bonded part (mixed with the part that is bonded and the part that is not bonded) (the part that is not bonded) If there is, the diffusibility will fall).
Further, it is possible to prevent the guide sheet 33 from being peeled off from the pipe 31 due to a decrease in the adhesive force during use of the present application mechanism. Furthermore, it is easy to replace the guide sheet 33.

  In the present application mechanism, a guide sheet 33 having low rigidity (that is, having elasticity) is used. For this reason, the lower end portion 53 of the pipe 31 can be screwed to the sheet metal 300 so as to urge the pipe 31 with the elasticity of the guide sheet 33. Thereby, the assembly of the present application mechanism is further facilitated.

Further, in the present application mechanism, the felt base 25 a is provided with a plurality of discharge ports 71 so that excess oil can flow into the oil pan 26.
If a large amount of oil is included in the felt 25, the uniformity of oil application to the oil application roller 16 is likely to be impaired. Therefore, it is preferable to provide the oil discharge port 71 and allow the oil pan 26 to collect excess oil.

In the present embodiment, the pipe 31 is disposed above the oil application roller 16.
Here, the pipe 31 may be completely above the oil application roller 16 (that is, the lower end of the pipe 31 may be above the upper end of the oil application roller 16), or the oil application roller 16. Alternatively, it may be only partially above the center (even if the center of the pipe 31 is above the center of the oil application roller 16).

  In the present embodiment, the felt 25 is located below the oil application roller 16. Here, the felt 25 being positioned below the oil application roller 16 means that the contact point between the felt 25 and the oil application roller 16 is below the center of the oil application roller 16.

In the present embodiment, PET having a thickness of 0.1 mm is used as the material for the guide sheet 33.
Here, if the guide sheet 33 is too thin, the guide sheet 33 is likely to be damaged when the copying machine 1 is assembled, and the elastic force of the guide sheet 33 is lowered, which is not preferable.
Therefore, the thickness of the guide sheet 33 is preferably set in the range of 0.025 mm to 0.25 mm.
In addition, as long as the resin has heat resistance, other materials than PET may be used.

That is, as the material of the guide sheet 33, it is preferable to use a material that can be formed into a thin plate having a thickness range as described above and has a heat resistance of about 200 ° C. and an oil resistance.
For example, a thin plate (film) of plastic (polyimide, polyethylene terephthalate, polyamide, etc.) or a thin plate of metal (stainless steel plate, etc.) can be used as the material of the guide sheet 33.

  In particular, as the material of the guide sheet 33, it is preferable to use a material that prevents the oil overflowing from the pipe 31 from permeating (a material that can prevent permeation of oil), that is, a material having oil resistance.

That is, the present application mechanism is configured to diffuse oil in the longitudinal direction by utilizing the surface tension generated by bringing the guide sheet 33 into contact with the pipe 31.
On the other hand, when a permeable material (for example, felt or the like) is used for the guide sheet 33, the oil is diffused only by a capillary phenomenon in the guide sheet 33. For this reason, the diffusibility of the oil in the longitudinal direction is reduced. Further, the oil stays inside the guide sheet 33 and tends to deteriorate.

Furthermore, since a certain amount of oil is accumulated in the guide sheet 33, the oil flow rate must be increased, which is uneconomical.
That is, when the guide sheet 33 of a type that soaks oil is used, the oil cannot be transmitted to the felt 25 unless the guide sheet 33 is soaked with a sufficient amount of oil. For this reason, a large amount of oil is required at the start of use of the present application mechanism (at the time of preparation for use) (the flow rate needs to be about 4 to 5 cc / min), and preparation for use takes time.
Further, since it cannot be determined from the outside whether or not the guide sheet 33 is dry (whether or not the guide sheet 33 is sufficiently soaked with oil), the oil flow rate is always 4 to 5 cc / min even when the use is not started. It is necessary to keep the degree.

  On the other hand, if the oil-resistant guide sheet 33 is used, it is not necessary to soak oil into the guide sheet 33. For this reason, the amount of oil can be reduced to 2 to 3 cc / min, and the preparation time for use can be greatly shortened.

Further, when a thin guide sheet 33 is used, it is preferable to handle the present application mechanism so as to avoid deformation of the guide sheet 33.
In particular, in the present application mechanism, the guide sheet 33 and the pipe 31 are brought into contact with each other using the elastic force (repulsive force) of the guide sheet 33. Therefore, when assembling the present application mechanism, the guide sheet 33 is easily deformed because of the action against the repulsive force of the guide sheet 33.

  Therefore, at the time of assembling the application mechanism, it is preferable to put a double-sided tape on the contact surface of the lower end 53 with the felt table 25a. The guide sheet 33 is preferably bent so as to contact the pipe 31 in a state where the guide sheet 33 is temporarily fixed to the felt base 25a by the double-sided tape. Thereby, the workability regarding the attachment of the guide sheet 33 can be improved, and the deformation of the guide sheet 33 can be prevented.

  The width (length in the longitudinal direction) of the oil application roller 16 and the felt 25 is preferably designed to be slightly longer than the width of the maximum size sheet used for printing. The width of the blade 29 is preferably wider than the width of the oil application roller 16, and the width of the fixing roller 11 is preferably designed to be substantially the same as the width of the oil application roller 16. The pressure roller 12 is preferably designed wider than the width of the fixing roller 11.

Moreover, in this application | coating mechanism, it is preferable that oil is fully diffused in a longitudinal direction between the outer wall surface of the pipe 31 and the intermediate part 52 (slit 61 and guide part 62) of the guide sheet 33 by surface tension.
For this reason, the width of the slit 61 in the guide sheet 33 is preferably about 0.5 mm to 5 mm.

As a result, the oil can be diffused in the longitudinal direction of the pipe 31 by surface tension without clogging the paper dust or dust in the slit 61.
In addition, when the width of the slit 61 is 0.5 mm or less, there is a possibility that dust or paper dust is clogged in the slit 61.
If the width of the slit 61 exceeds 5 mm, the surface tension becomes difficult to work. Therefore, the oil diffusion state deteriorates, and it becomes difficult to spread the oil to all the guide portions 62 and the slits 61.
Further, the guide portion 62 of the guide sheet 33 may be formed so as to become wider toward the felt 25.

In the present application mechanism, it is preferable to provide as many slits 61 (guide portions 62) as possible over the entire width of the intermediate portion 52 (width in the longitudinal direction) with respect to the intermediate portion 52 of the guide sheet 33 ( For example, it is preferable to form more slits 61 than the number of holes 41 of the pipe 31).
The oil flowing through the intermediate portion 52 is difficult to move so as to cross (over) the slit 61. For this reason, if a large number of slits 61 are formed, the oil diffused in the longitudinal direction by the surface tension between the pipe 31 and the guide sheet 33 (intermediate portion 52) reaches the felt 25 while maintaining its diffusion state. It becomes possible.

  The length L (see FIG. 1) from the contact point C to the pipe 31 in the guide sheet 33 (see FIG. 1) is preferably 1 mm or more. Thereby, it is possible to avoid clogging with dust and paper dust in the slit 61 in the vicinity of the contact C. Therefore, it is possible to avoid the trouble that oil accumulates up to the upper end 51 between the guide sheet 33 and the pipe 31 and the oil flows from both ends of the pipe 31 in the longitudinal direction.

Further, in the present embodiment, the guide sheet 33 is composed of the intermediate portion 52 provided with the slit 61, and the upper end portion 51 and the lower end portion 53 that are located at both ends thereof and are not provided with the slit 61.
Here, the slit 61 may be provided also in the lower end portion 53.

Further, as described above, a piezo-type pump or an electromagnetic pump can be used as the pump 22 of the coating mechanism.
Piezo-type pumps operate at the frequency of an AC power source, and are more expensive (about twice the price of an electromagnetic pump) than an electromagnetic pump driven by a DC power source. For this reason, it is also preferable to use an inexpensive electromagnetic pump.

As an electromagnetic pump constituting the pump 22 of the coating mechanism, one that can be driven by a DC pulsed current (a pulse current having a period of 30 ms to 300 ms and a pulse width of 3 ms to 50 ms) can be used.
Further, the flow rate of such an electromagnetic pump can be adjusted to 1 to 10 cc / min. By adjusting the pulse width and period of the supplied pulse current. Can be set within the range.

As described above, when the oil-resistant guide sheet 33 is used, the flow rate for suitably using this coating mechanism is usually 2 to 3 cc / min. Range.
On the other hand, when a material having permeability (such as felt) is used as the material of the guide sheet 33, 4 to 5 cc / min. It is necessary to supply oil at a flow rate of.

In the present embodiment, the kinematic viscosity of the oil used in the coating mechanism is 100 cs at 25 ° C. However, this coating mechanism can use 100-300 cs at 25 ° C.
Here, oil less than 100 cs has a low flash point and is dangerous when used in the fixing device 217. In addition, oil having a kinematic viscosity exceeding 300 cs is difficult to supply with a piezo-type or solenoid-type pump.

In the present embodiment, silicone oil having a dimethylpolysiloxane structure is used. This oil has a relatively small viscosity change with temperature, the kinematic viscosity at 0 ° C. is about twice as high as that at 25 ° C., and the kinematic viscosity at 50 ° C. is about ½ at 25 ° C. It has the characteristic of becoming low.
In addition, the change of the viscosity with respect to the temperature in the oil that can be used in the application mechanism is not limited to the above characteristics. Of course, it is also preferable to use an oil having a smaller kinematic viscosity than the above characteristics. Moreover, what is necessary is just to adapt the structure of each part according to the characteristic, when using oil with large dynamic viscosity.

  In the present embodiment, silicone oil is used as the release agent. However, this application mechanism is not limited to silicone oil, and any other release agent can be used.

  In the present embodiment, oil is applied to the fixing roller 11 of the fixing device 217 by the application mechanism. However, the present invention is not limited to this, and the oil application roller 16 may be brought into contact with the pressure roller 12 which is the other fixing roller to apply the oil to the pressure roller 12. Further, oil may be applied to both the rollers 11 and 12.

  In the present embodiment, the oil application roller 16 is rotated by following the fixing roller 11. However, the present invention is not limited to this, and the oil application roller 16 may be rotated by a driving mechanism different from the fixing roller 11. The rotation direction of the oil application roller 16 may be the same direction as the fixing roller 11 or the opposite direction.

  In this embodiment, a heat-resistant nomex felt having a thickness of 3 mm is used as the felt 25. Here, as the felt 25, it is possible to use a heat-resistant nomex felt having a thickness of about 1 mm to 5 mm.

In the present embodiment, the guide sheet 33 and the felt 25 are shown as separate members. However, the present invention is not limited to this, and the guide sheet 33 and the felt 25 may be integrally formed.
That is, the lower end portion 53 of the guide sheet 33 may be extended to the vicinity of the oil application roller 16 and the felt 25 may be disposed thereon. In this case, the oil discharge port 71 is provided in the lower end portion 53. Further, the lower end 53 is screwed to the sheet metal 300.

In the present embodiment, the laser writing units 227a to 227d scan and expose a laser beam to perform optical writing on the photosensitive member. However, the present invention is not limited to this, and instead of the laser writing units 227a to 227d, a solid scanning writing optical system (LED head) including a light emitting diode array and an imaging lens array may be used.
The LED head is smaller than the laser writing units 227a to 227d and has no moving parts and is silent. Therefore, it can be suitably used for an image forming apparatus such as a tandem digital color copying machine that requires a plurality of optical writing units such as the copying machine 1.

In the present embodiment, the copying machine 1 is a printing apparatus (color image forming apparatus) capable of color printing.
In a color image forming apparatus, the use of a release agent is very important, and the print quality (image formation quality) depends greatly on the state of the release agent. Therefore, it is very effective to use this coating mechanism.
However, as a matter of course, the same effect can be obtained even when the application mechanism is applied to a printing apparatus for monochrome printing (monochrome image forming apparatus).

  Further, the release material application mechanism of the present invention is a release agent application mechanism for applying a release agent to a fixing roller of a printing apparatus, wherein the release agent is formed from a plurality of holes formed in a pipe extending along the fixing roller. In the release agent application mechanism that supplies the release agent discharged from the pipe through the release agent guide to the release agent application roller that rotates while contacting the fixing roller. The roller is provided with an application member for applying a release agent from the lower side, the pipe is arranged above the release agent application roller, and the release agent guide is discharged from the pipe. Designed to supply the release agent to the application member, and part of the release agent guide swells away from the normal passing through the center of the pipe on the side away from the release agent application roller. Release agent application mechanism, the release agent guide is The lower end is fixed so as to be positioned on the coating member, and extends from the fixed position in a direction away from the release agent coating roller from the vertical line, and further from the vertical line to the release agent coating roller side. It can also be expressed as a structure that is designed to be folded back into contact with the lower part of the pipe.

  Further, conventionally, a release agent (silicone oil or the like) that overflows and drops from a plurality of holes of a release agent supply pipe member is dropped near a member to be coated (a fixing roller or a pressure roller). Therefore, the viscosity of the release agent is relatively high although it is through an intermediate member (release agent application roller or release agent supply felt) that supplies the release agent in contact with the member to be applied. It can be said that there is a problem that the toner cannot be sufficiently diffused and the release agent supply in the longitudinal direction is not uniform, and a good toner image cannot be fixed on the paper. Further, when the supply path is provided close to a portion having a high temperature when the release agent is supplied to the supply body via the guide member, there is a problem that the release agent is easily deteriorated due to the influence of the high temperature. It can be said that there is. In addition, an object of the present invention is to provide a guide member between the supply target and the pipe member, and after the mold release agent is diffused by the guide member and the pipe member, the guide member is provided in a portion where the ambient temperature is low. By providing a supply path that guides the release agent, the release agent can be supplied to the supply object without being exposed to a very high temperature, so that the deterioration of the release agent can be prevented and uniform release by the guide member. It can be said that the present invention is to provide a release agent supply device that can supply the agent, a fixing device including the device, and an image forming apparatus including the fixing device.

  The guide sheet 33 is heat resistant and can be a thin one having a thickness of about 0.025 mm to 0.25 mm. However, though it depends on the material, if it is too thin, the guide sheet 33 is likely to be damaged at the time of assembly in the factory, and the elastic force is lowered. The guide sheet 33 is preferably made of a thin material such as plastic or metal. Any material having heat resistance (about 200 ° C.) and oil resistance can be used, and a metal plate such as polyimide, polyethylene terephthalate, polyamide or stainless steel plate is used. For example, when a film or metal thin plate is used as the guide sheet 33, the guide sheet 33 is attached toward the pipe 31 using the elasticity of the film member or metal thin plate. It is fixed to the base by a fastening member such as a screw so as to be biased. At this time, since the guide sheet 33 and the pipe 31 are not bonded to each other, the oil overflowing on the opposite side of the pipe 31 is also transmitted to the back surface of the guide sheet 33 from the opening that is a partition portion between the pipe 31 and the guide sheet 33. be able to. Then, the guide sheet 33 is guided by using the both sides of the guide portion of the guide sheet 33 toward the fixing roller which is the supply body due to the inclination of the guide sheet 33.

  The size of the opening (slit 61) in the guide sheet 33 is such that the release agent (silicone oil) is removed by capillary action between the outer wall surface and the guide portion of the pipe 31, and the outer wall surface and the opening portion (slit 61) of the pipe 31. Since it is necessary to diffuse in the longitudinal direction, the width of the opening is preferably about 0.5 mm to 5 mm. This is because the oil can be diffused in the longitudinal direction of the pipe 31 by capillary action without clogging with paper dust or dust. If it is less than 0.5 mm, dust and paper dust may be clogged. If it exceeds 5 mm, the capillary phenomenon becomes difficult to work and the state of diffusion of the release agent deteriorates, and the release agent is spread and supplied to the guide part. It falls without being able to. For the above reason, L is set to 1 mm or more so that the trouble that the release agent overflowing above the inclined part of the guide sheet 33 due to clogging with dusts or the like flows down from both ends in the longitudinal direction does not occur.

  The guide portion of the guide sheet 33 may be formed so as to become wider toward the supply target side. However, in the embodiment, the width may be kept as it is, and the ratio may be 1: 1, which is not limited thereto. The ratio may be varied without any change. When a guide sheet 33 formed of a thin steel plate or plastic (film or thin molded product) is used in contact with the pipe 31, the guide sheet 33 is reliably brought into contact with the pipe 31 using the elastic force of the guide sheet 33. Thus, the guide sheet 33 may be urged toward the pipe 31 by using a fastening member such as a screw so as to be urged. Since the guide sheet 33 is not affixed to the pipe 31 using an adhesive or the like, it is easy to assemble, and the oil diffusibility (uniform supply property) may be partially impaired due to variations in the use of the adhesive. Absent. Moreover, it does not peel off during use, and only the guide sheet 33 can be easily replaced at the time of replacement.

  In this embodiment, a color image forming apparatus is described as the image forming apparatus. This is because the use of a release agent is very important in a color image forming apparatus, and the quality of image formation is greatly affected by the state of the release agent. However, it goes without saying that the present invention is also effective for a monochrome image forming apparatus.

  The present invention can also be expressed as the following first to seventh release agent supply devices, first fixing devices, and first image forming devices. In other words, the first release agent supply device is a release agent supply device that supplies a release agent to a fixing device having a fixing unit including a rotating fixing roller and a pressure roller in pressure contact with the fixing roller. An intermediate guide means is provided by allowing a release agent supplied from a release agent supply pump to overflow from the plurality of holes from a cylindrical body disposed on the top of the roller and provided with a plurality of holes in the axial direction of the upper surface. In the release agent supply device that supplies the release agent to at least one of the fixing roller and the pressure roller via the guide member, the guide member that forms the intermediate guide means is disposed so as to bypass the high temperature portion. . According to this configuration, since the release agent is guided around the high temperature portion, it is possible to reduce deterioration of the release agent due to heat radiated from the fixing roller and the oil application roller.

  Further, in the second release agent supply device, in the first release agent supply device, the guide member has a curved portion, and is once guided in a direction away from the supply target, and then returned to the supply target. The mold release agent is guided to and supplied to the supply target. According to this configuration, the guide member is bent and the release agent is once supplied in a direction away from the supply target (a direction away from the fixing roller and the oil application roller), and then returns toward the supply target. By guiding, it is possible to avoid radiant heat from the fixing roller and oil application roller to the release agent, reduce exposure of the release agent to high temperature, and reduce deterioration of the release agent due to heat. it can.

  Further, the third release agent supply device is the first or second release agent supply device, wherein the guide member is disposed on the lower side of the cylindrical body and is close to the supply target formed on the guide member. The guide member has a partition portion formed of an opening and a partition portion, and the guide member is in contact with the cylindrical body at a location where both the partition portion and the guide portion are formed. According to this configuration, the guide member has a guide portion that extends to a position close to the supply target, and a partition portion that includes an opening that extends substantially in the same manner. The release agent diffused in the longitudinal direction of the body is transmitted to the guide member and can be guided to the vicinity of the supply target body while maintaining the diffusion state, so that the uniform release agent can be supplied.

  Further, in the fourth release agent supply device, in any one of the first to third release agent supply devices, the guide member is formed of a non-permeable material, and both surfaces of the guide portion of the guide member are provided with the release agent. It is the structure which supplies a mold release agent by transmitting. According to this configuration, the release agent does not penetrate into the inside of the guide member by being formed of a non-penetrable material, and the guide can be quickly guided using both sides of the guide portion of the guide member. Since the release agent does not stay on the surface of the part for a long time, deterioration due to heat can be reduced. Moreover, since the release agent does not easily stay on the guide member, the flow rate of the release agent overflowing from the cylindrical body can be reduced. This also has the effect of reducing the deterioration of the release agent.

  Further, the fifth release agent supply device is configured such that, in the third release agent supply device, the guide member is brought into contact with the cylindrical body by the elastic force of the guide member. According to this configuration, by utilizing the elastic force of the guide member itself, the predetermined gap can be provided between the guide portion of the guide member and the cylindrical body and can be reliably positioned. In addition, the sixth release agent supply device is configured such that, in the third release agent supply device, the guide member is in contact with the cylindrical state in a state where the guide member is inclined on the lower side of the cylindrical body. According to this configuration, since the guide member is in contact with the lower side of the tubular body while being inclined, the release agent overflowing from the upper hole of the tubular body is received by the guide member, and the capillary phenomenon occurs. Can be diffused and the release agent can be guided toward the supply target.

  Further, the seventh release agent supply device is the third release agent supply device, wherein the guide portion and the partition portion of the guide member are alternately provided, and the number thereof is the release portion provided in the cylindrical body. The configuration is set to be sufficiently larger than the number of discharge holes for the agent. According to this configuration, the guide part and the partition part provided in the guide member are alternately provided in a sufficiently larger number than the outflow hole of the release agent, so that the release agent is elongated by the cylindrical body and the guide member. The mold release agent can be guided while maintaining the state diffused in the direction.

  The first fixing device is a fixing device having a rotating fixing roller and a fixing unit composed of a pressure roller that is in pressure contact with the fixing roller. The first fixing device is disposed above the fixing roller and has a plurality of holes in the axial direction on the upper surface. The release agent supplied from the release agent supply pump is caused to overflow from the plurality of holes from the cylindrical body provided with the intermediate member, and is supplied to at least one of the fixing roller and the pressure roller. In the fixing device including the release agent supply device to be supplied, any one of the first to seventh release agent supply devices is provided. According to this configuration, the above-described effect can be obtained in the fixing device. Further, the first image forming apparatus has a first fixing device. According to this configuration, the above-described effect can be obtained by providing the fixing device in the image forming apparatus, and favorable image formation can be performed.

  The present invention can be suitably implemented in a release agent coating mechanism, a fixing device, and a printing device that apply a release agent to a fixing roller of a printing device.

It is sectional drawing which shows the structure of the pipe part in the oil application mechanism concerning one Embodiment of this invention. It is explanatory drawing which shows the structure of a digital color copying machine which has a fixing device provided with the oil application | coating mechanism shown in FIG. FIG. 3 is a perspective view showing a configuration of a fixing device provided in the digital color copying machine shown in FIG. 2 and having the oil application mechanism shown in FIG. 1. FIG. 3 is a cross-sectional view showing a configuration of a fixing device provided in the digital color copying machine shown in FIG. 2 and having the oil application mechanism shown in FIG. 1. It is an expanded view which shows the structure of the pipe part shown in FIG. It is explanatory drawing which shows the conventional oil application technique. It is explanatory drawing which shows the conventional oil application technique.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Fixing roller 12 Pressure roller 13 Peeling claw 14 Cleaning roller 15 Roller temperature detector 16 Oil application roller (release agent application roller)
21 Oil tank 22 Pump 23 Tube member 24 Pipe part 25 Felt (coating member)
25a Felt stand (coating material)
26 Oil pan 27 Tube member 28 Oil sensor 29 Blade 31 Pipe 33 Guide sheet (release agent guide)
51 Upper end portion 52 Intermediate portion 53 Lower end portion 61 Slit 62 Guide portion 71 Oil discharge port 217 Fixing device 300 Sheet metal B Screw C Contact S Normal

Claims (10)

A release agent application mechanism for applying a release agent to a fixing roller of a printing apparatus,
The release agent is discharged from a plurality of holes formed in a pipe extending along the fixing roller,
In the release agent application mechanism that supplies the release agent discharged from the pipe via the release agent guide to the release agent application roller that rotates while contacting the fixing roller.
The release agent application roller has an application member for applying a release agent from below,
The pipe is arranged above the release agent application roller,
The release agent guide is designed to supply the release agent discharged from the pipe to the application member,
Furthermore, a part of the release agent guide swells to a side farther from the release agent application roller than a perpendicular passing through the center of the pipe. The release agent guide is
The lower end is fixed to the application member,
From this fixed position, it is designed to extend once in the direction away from the release agent application roller from the vertical line, and to be folded back toward the release agent application roller side from the vertical line and to be in contact with the lower part of the pipe. The release agent coating mechanism according to claim 1, wherein   The release agent application mechanism according to claim 2, wherein the release agent guide has a slit extending from a lower end portion toward a contact point with the pipe.   4. The release agent application mechanism according to claim 3, wherein the slit extends on the release agent guide beyond the contact point with the pipe.   The release agent application mechanism according to claim 2, wherein the release agent guide is in contact with the pipe in an inclined state.   The release agent coating mechanism according to claim 3, wherein the slits are formed more than the holes of the pipe.   The release agent application mechanism according to claim 2, wherein the release agent guide is in contact with the pipe in an inclined state with the side closer to the application member lowered.   The release agent application mechanism according to claim 1, wherein the release agent guide is made of a material having a release agent resistance.   A fixing device comprising the release agent coating mechanism according to claim 1.   A printing apparatus comprising the fixing device according to claim 9.

Images