JP4075382B2 - Recording medium peeling apparatus, fixing apparatus using the same, and electrophotographic apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrophotographic apparatus such as a printer, a copying machine, and a facsimile machine, and more particularly to a recording medium peeling apparatus in a fixing apparatus that can maintain high image quality and high reliability with a simple configuration.
[0002]
[Prior art]
In general, an electrophotographic apparatus forms an electrostatic latent image on a photosensitive member, develops it with toner, transfers the developed toner image to a recording medium such as paper, and fixes it to the recording medium with heat. Yes. In the fixing process, a heating member provided with a heating element is placed at a position in contact with the unfixed image surface of the recording medium on which the unfixed toner image is formed, and from the other surface of the recording medium. In this case, the recording medium is pressed against the heating member by the pressure member, and the toner image is pressure-bonded while being heated and melted to be fixed to the recording medium. In order to obtain high image quality during the fixing process, the heating temperature and pressure of the toner image and the fixing time during which the toner image receives heat and pressure are important factors.
[0003]
In addition, as the speed, image quality, and power saving of electrophotographic devices increase, a low heating amount is stably supplied to the toner image, and the heat transfer efficiency from the heating element to the toner image is improved, and then the fixing is performed. The need to secure time increases. Therefore, as described in JP-A-10-161464 and JP-A-2001-117397, a heating member or a pressure member is used as a belt-like member to reduce the heat capacity of the entire fixing device, and further, from the heating element to the toner. It is known that the heat transfer efficiency to the image is improved and the contact distance between the recording medium, the heating member, and the pressure member is increased.
[0004]
[Problems to be solved by the invention]
However, in the fixing device having the above configuration, the melted and compressed toner image becomes a hot-melt adhesive between the heating member and the recording medium, and therefore, the toner image arrives at the heating member side and causes the jamming of the recording medium. It becomes. In particular, as described in JP-A-10-161464, when the heating member is used as a roller and a part of the belt that is a pressure member is wound around, the recording medium is curled toward the heating member. It is easy to adhere, and the jam occurrence rate in the fixing device is high.
[0005]
Therefore, a method is used in which a peeling nail is provided on the heating member and the recording medium is forcibly peeled off from the heating member. However, when the recording medium is peeled off, the peeling nail contacts and rubs the toner image, thus degrading the image quality. To do. Further, there is a defect that the molten toner adheres to the peeling claw and accumulates, and the adhered molten toner comes into contact with the recording medium to cause clogging of the recording medium.
[0006]
SUMMARY OF THE INVENTION An object of the present invention is to provide a recording medium peeling apparatus capable of eliminating such drawbacks of the prior art and maintaining high image quality and high reliability with a simple configuration, and a fixing apparatus and an electrophotographic apparatus using the same. There is.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a first means of the present invention is a recording medium peeling apparatus for forcibly peeling a recording medium on which a toner image is fixed by thermocompression bonding from a rotating heating member.
Corresponding to the size in the width direction of the plurality of types of the recording media to be used, a plurality of peeling claws are supported on the shaft in pairs on the left and right sides at predetermined intervals along the width direction of the heating member,
The interval W1 inside the separation claw in each pair is wider than the lateral width W2 of the image forming area in the recording medium to be separated and smaller than the lateral width W3 of the recording medium (W2 <W1 <W3). It is set individually for each pair of peeling nails,
In addition, the position of the claw tip of each peeling claw is set so as to be gradually away from the fixing outlet of the recording medium along the peeling claw on the inner side in the width direction from the peeling claw on the outer side in the width direction of the shaft. By
The recording medium of each size is peeled off only by the pair of peeling claws corresponding to the size .
[0008]
According to a second means of the present invention, in the first means, the peeling inclination angle of each peeling claw decreases in order from the peeling claw on the outer side in the width direction of the shaft along the peeling claw on the inner side in the width direction. it is characterized in that there.
[0009]
The third means of the present invention is characterized in that, in the first or second means, each of the peeling claws is integrally formed .
[0010]
A fourth means of the present invention is characterized in that the recording medium peeling device of the first to third means is arranged at a position where the recording medium coming out from the fixing outlet is peeled off from the heating member .
[0011]
According to a fifth means of the present invention, in the fourth means, a part of the pressure belt is wound around a part of the heating member, and the recording medium is pressed against the heating member by the pressure belt. The recording medium peeling device is disposed in the vicinity of the fixing outlet portion of the fixing device .
[0012]
The sixth means of the present invention is characterized in that the fixing device of the fourth or fifth means is an electrophotographic apparatus .
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 is a perspective view of the periphery of a recording medium peeling device of a fixing device according to a first embodiment, FIG. 2 is a schematic configuration diagram of an electrophotographic apparatus using the fixing device, and FIG. 3 is a schematic configuration diagram of the fixing device. .
[0015]
First, an overall schematic configuration and operation of the electrophotographic apparatus will be described with reference to FIG. A drum-like or belt-like (in the present embodiment, drum-like) intermediate transfer device 11 is disposed at substantially the center of the electrophotographic apparatus, and a photosensitive device 12, a transfer device 13, a separation device 14, and an intermediate transfer device cleaning means are disposed around the intermediate transfer device 11. 15 etc. are arranged.
[0016]
Around the belt-shaped or drum-shaped (belt-shaped in this embodiment) photosensitive device 12, a charger 16, a photosensitive member cleaning unit 17, a residual image removing unit 18, and the like are arranged. Developers 19K (black), 19Y (yellow), 19M (magenta), and 19C (cyan) enclosing toners that are finely colored powders of four different colors are arranged in an overlapping manner, and below the exposure means 20, Furthermore, a recording medium holding means 21 and a recording medium supply device 22 on which a sheet-like recording medium 9 such as paper or OHP is stacked are arranged below the recording medium. A fixing device 10 and a recording medium discharge device 23 according to the present invention are arranged on the upper part of the electrophotographic apparatus.
[0017]
In this configuration, the charger 16 uniformly charges the surface of the photosensitive device 12. Next, exposure is performed in dot units by the exposure unit 20 based on printing information such as images and characters from a personal computer or an image scanner, and an electrostatic latent image is formed on the surface of the photosensitive device 12.
[0018]
Thereafter, the electrostatic latent image is visualized as a toner image by being supplied with toner by any of the developing devices 19K, 19Y, 19M, and 19C, and developed, and the photosensitive device 12 and the intermediate transfer device 11 are in contact with each other. It is conveyed to the transfer position T1. At the first transfer position T1, the toner image is transferred to the surface of the intermediate transfer device 11 due to a potential difference between the photosensitive device 12 and the intermediate transfer device 11 supplied from a power source (not shown).
[0019]
After passing through the first transfer position T1, the surface of the photosensitive device 12 is irradiated with light by the afterimage removing means 18 to drop the potential below a certain level, and the electrostatic latent image is erased. The toner remaining on the surface without being transferred at T1 is cleaned and prepared for the formation of the next toner image.
[0020]
By repeating this process as many times as necessary for each color, toner images of respective colors suitable for image and character information are formed on the surface of the intermediate transfer device 11 in an overlapping manner. Thereafter, the toner image is collectively transferred to the recording medium 9 supplied from the recording medium holding unit 21 by the recording medium supply device 22 by the transfer device 13 at the second transfer position T2. The recording medium 9 to which the toner image has been transferred is peeled off from the intermediate transfer device 11 by the separation device 14, transported to the fixing device 10, fixes the toner image on the recording medium 9, and is discharged by the recording medium discharge device 23.
[0021]
As shown in FIG. 3, the fixing device 10 includes a heating roller 1, a pressure roller 2, a tension roller 3, a pressure belt 4, a heating source 5, a peeling claw 6, a thermistor 7 for temperature control means, and the like. .
[0022]
The heating roller 1 is provided with a release layer such as tetrafluoroethylene perfluoroalkyl vinyl ether copolymer (PFA) or fluorine resin on a hollow core metal such as aluminum, or between the core metal and the release layer. A heat-resistant elastic layer such as silicone rubber is provided on the metal core, or only a heat-resistant elastic layer is provided on the core metal, and a heating source 5 such as a heater lamp is installed therein, and the heat from the heating source 5 passes through the heating roller 1 to form a toner image. 8 and the recording medium 9.
[0023]
The pressure roller 2 is a metal roller such as aluminum, or a heat-resistant elastic layer such as silicone rubber provided on the surface of the metal roller. The pressure roller 2 is pressed against the heat roller 1 with a pressure belt 4 sandwiched by a spring or the like (not shown). Yes. The tension roller 3 is a hollow or solid metal roller such as aluminum. The tension roller 3 is elastically biased in the lower left direction in the drawing by a spring or the like (not shown) in order to apply tension to the pressure belt 4.
[0024]
As the pressure belt 4, for example, an endless nickel belt by electroforming with a thickness of 30 to 50 μm or a polyimide resin endless belt with a thickness of 40 to 100 μm is used. In addition, a silicone rubber layer having a thickness of 50 to 300 μm is provided on the outer peripheral surface of these endless belts, or the outer peripheral surface is subjected to mold release treatment with PFA or fluorine resin.
[0025]
The pressure belt 4 is stretched between the pressure roller 2 and the tension roller 3, and the pressure belt 4 is pressed against the heating roller 1 by the pressure roller 2. The heating roller 1 is rotationally driven in the P direction by a driving source (not shown), and the rotation of the heating roller 1 causes the pressure roller 2, the tension roller 3, and the pressure belt 4 to be driven and rotated in the Q direction. The recording medium 9 on which the toner image 8 unfixed by these rotations is mounted has a nip portion in which a part of the pressure belt 4 is wound around the heating roller 1 so that the surface of the toner image 8 is in contact with the heating roller 1. It passes through and is carried out from the fixing outlet O in the direction of the arrow.
[0026]
The thermistor 7 is in sliding contact with the outer peripheral surface of the heating roller 1, and the fixing temperature is controlled by detecting the surface temperature of the heating roller 1 with the thermistor 7 and adjusting the amount of current supplied to the heating source 5.
[0027]
As shown in FIG. 3, the recording medium peeling device 24 is disposed at a position where the recording medium 9 coming out from the fixing outlet O is forcibly peeled from the heating roller 1, and has a peeling claw 6 and a shaft 60 that supports the peeling claw 6. Yes. The peeling claw 6 is formed of, for example, a heat-resistant synthetic resin and has a substantially triangular side surface. The claw tip 25 is in the vicinity of the fixing outlet O and is in sliding contact with the outer peripheral surface of the heating roller 1. It is close.
[0028]
As shown in FIGS. 1 and 5, the peeling claw 6 includes a plurality of pairs of peeling claws 6a to 6d. The peeling claw 6a is on the outermost side, the peeling claw 6b is on the inner side, and the peeling claw 6d is on the innermost side. The peeling claws 6d are supported on the shaft 60 in pairs on the left and right sides at predetermined intervals. The claw tip portions 25a to 25d of the peeling claws 6a to 6d are set at positions away from the fixing outlet O (see FIG. 3) in order. Accordingly, the claw tip 25a of the outermost peeling claw 6a in the axial direction of the heating roller 1 is closest to the fixing outlet O, and the claw tip 25d of the innermost peeling claw 6d is the most fixing outlet O. It is in the position away from.
[0029]
As shown in FIG. 4, the recording medium 9 generally used has a paper width determined by its type. As shown in FIG. 5, the peeling claws 6a, 6a having the widest gap in the axial direction and the claw tip 25a closest to the fixing outlet O are used to peel off the letter size and legal size recording media 9a. 6b and 6b peel off the A4 size recording medium 9b, but the peeling claws 6c and 6c peel off the B5 size recording medium 9c. The peeling claws 6d and 6d far from the portion O are used to peel off the A5 size recording medium 9d.
[0030]
By setting the interval between the peeling claws 6 and the position of the claw tip 25 as described above, a large size recording medium 9a, for example, is peeled only by the peeling claws 6a, 6a, and a small size recording medium 9d, for example, It is possible to automatically and reliably peel off according to the size of the recording medium 9 without moving the position of the peeling claw corresponding to the size of the recording medium so that the peeling is performed only by 6d and 6d.
[0031]
As shown in FIG. 6, the interval W1 inside the peeling claw 6 (6a to 6d) is wider than the lateral width W2 of the image forming region 26 in the recording medium 9 to be peeled, and narrower than the lateral width W3 of the recording medium 9. (W2 <W1 <W3). This dimensional relationship is individually set for each of the peeling claws 6a to 6d.
[0032]
By making the dimensional relationship of W2 <W1, the peeling claw 6 (6a to 6d) can always contact only the position outside the image forming area 26 of the recording medium 9 when the recording medium 9 is peeled off. 6a-6d) does not damage the toner image immediately after fixing, and does not deposit foreign matters such as molten toner on the surface of the peeling claw 6 (6a-6d).
[0033]
Next, the operation of the fixing device 10 will be described with reference to FIGS. The recording medium 9 onto which the unfixed toner image 8 formed by each process of electrophotography is transferred has the toner image 8 surface in contact with the heating roller 1 and is directed from the R direction toward the axial center of the heating roller 1. It enters and is nipped between the nip portion of the heating roller 1 and the pressure belt 4 and conveyed. Thereafter, the recording medium 9 is moved while being heated and pressurized with the rotation of the heating roller 1 while being in close contact with the heating roller 1, and while passing through the heating roller 1, the toner image 8 is melted and pressed on the recording medium 9 to be fixed. Ends.
[0034]
When the recording medium 9 is ejected from the recording medium outlet O, the melted and pressed toner image becomes an adhesive between the heating roller 1 and the recording medium 9, and therefore the recording medium 9 is not peeled off from the heating roller 1. Will occur. The recording medium 9 that is in close contact with the heating roller 1 is forcibly separated by the separation claws 6a to 6d.
[0035]
As described above, the peeling claws 6a to 6d are installed at positions corresponding to the end portions thereof according to the width dimensions of various recording media 9, and the claw tip portions 25 to 25d are sequentially moved away from the recording medium outlet O. Therefore, the toner image immediately after fixing can be peeled off without being damaged, depending on the size of the recording medium 9.
[0036]
FIG. 7 is a diagram showing a second embodiment of the present invention. The difference from the recording medium peeling device 24 shown in FIG. 1 is that the peeling claws 6a to 6d are integrated, and the inside of the peeling claws 6d and 6d is connected to the connecting portion 27. It is the point connected by. When the recording medium 9 passes through the recording medium outlet O, the connecting portion 27 is recessed from the claw tip portions 25 of the separation claws 6a to 6c so as not to contact the image forming region 26 of the recording medium 9.
[0037]
Thus, by making peeling claw 6 (6a-6d) into an integrated type, the assembly precision of peeling claw 6 (6a-6d) increases, and also the number of parts decreases, and set of peeling claw 6 (6a-6d) Installation work can be simplified and inexpensive.
[0038]
FIG. 8 is a diagram showing a third embodiment of the present invention. The difference from the recording medium peeling device 24 shown in FIG. 7 is that the tip inclination angle (peeling inclination angle) θ of the peeling claws 6 (6a to 6d) is It is the point which made it small sequentially toward the axial direction center part of the heating roller 1. FIG. That is, the tip inclination angle θa of the peeling claw 6a> the tip inclination angle θb of the peeling claw 6b> the tip inclination angle θc of the peeling claw 6c> the tip inclination angle θd of the peeling claw 6d. Although the present embodiment shows an example in which the peeling claws 6a to 6d are of an integrated type, the present embodiment can also be applied to a recording medium peeling device 24 in which the peeling claws 6a to 6d are separated as shown in FIG.
[0039]
According to this embodiment, the recording medium 9 having a large width dimension is peeled off at a large peeling angle by a portion outside the peeling claw 6 (for example, the part of the peeling claw 6a), and the recording medium 9 having a small width dimension is peeled off by the peeling claw 6. Therefore, only the end of the recording medium 9 can be brought into contact with the peeling claw 6 at the time of peeling, as in the above-described embodiment.
[0040]
FIG. 9 is a diagram showing a fourth embodiment of the present invention. In this embodiment, individual peeling claws 6a to 6d are provided separately or integrally on one side of the shaft 60, and the other side of the shaft 60 is provided on the other side. A common peeling claw 6e is provided. The position of the claw tip 25e of the common claw 6e is substantially coincident with the claw tip 25a of the peel claw 6a, and the tip inclination angle θe of the common peel claw 6e is, for example, the tip inclination angle θc of the separation claw 6c at the intermediate position. It is about the same. The present embodiment is applied to an electrophotographic apparatus of a type in which the recording medium 9 is transported on one side reference.
[0041]
In the above-described embodiment, the side surface shape of the tip portion has been described with respect to the peeling claw.
[0042]
Although the case where the peeling claw is fixed to the shaft has been described in the above embodiment, the peeling claw can be supported on the shaft and the tip of the peeling claw can be lightly elastically biased to the peripheral surface of the heating roller by a spring member or the like.
[0043]
In the above embodiment, an electrophotographic apparatus to which recording media of various sizes can be applied has been described. However, when the size of the recording medium to be used is fixed, such as an A4 size electrophotographic apparatus, a pair of peeling nails is used. It is only necessary to provide it.
[0044]
In the above embodiment, the heating roller is used in the fixing device, but a heating member having another configuration such as a heating belt may be used. When a heating belt is used, a pressure belt may be used as the pressure member as in the above embodiment, or a pressure roller may be used.
[0045]
In the structure in which a part of the pressure belt is wound around a part of the heating member as in the above embodiment, the present invention is particularly effective because it tends to curl toward the heating roller when the recording medium is peeled off.
[0046]
【The invention's effect】
The present invention of claim 1 wherein (first means), there is provided a recording medium peeling device to force peeled from the heating member for rotating a recording medium which fixes the toner image by heat and pressure, the width of the plurality of types of the recording medium to be used Corresponding to the size in the direction, a plurality of peeling claws are supported on the shaft in a pair of left and right at predetermined intervals along the width direction of the heating member, and the interval W1 inside the peeling claws in each pair is: Set individually for each pair of peeling claws such that the width W2 of the image forming area in the recording medium to be peeled is wider and narrower than the width W3 of the recording medium (W2 <W1 <W3), and The position of the claw tip portion of each peeling claw is set so as to be gradually away from the fixing outlet portion of the recording medium along the peeling claw on the inner side in the width direction from the peeling claw on the outer side in the width direction of the shaft. ,each Is the recording medium is characterized in being peeled off by only separating claw pairs corresponding to the size.
With this configuration, the toner image immediately after fixing can be peeled off automatically and reliably according to the size of the recording medium without moving the position of the peeling claw corresponding to the size of the recording medium. In addition, since foreign matters such as molten toner do not accumulate on the peeling claw without being damaged, the recording medium can be peeled without clogging, and high image quality and high reliability can be maintained.
[0047]
In the present invention according to claim 2 (second means), the peeling inclination angle of each peeling claw decreases in order from the peeling claw on the outer side in the width direction of the shaft along the peeling claw on the inner side in the width direction. It is characterized by this. With this configuration, each recording medium is always peeled outside the printing area at the end, the peeling claw does not rub against the toner image, and image quality deterioration can be prevented.
[0048]
The present invention according to claim 3 (third means) is characterized in that the peeling claws are integrally formed . With such a configuration, the assembling accuracy of each peeling claw is increased, the number of parts is reduced, the assembling work of the peeling claw can be simplified, and the cost is low.
[Brief description of the drawings]
FIG. 1 is a perspective view of a periphery of a recording medium peeling device of a fixing device according to a first embodiment of the present invention.
FIG. 2 is a schematic configuration diagram of an electrophotographic apparatus using the fixing device.
FIG. 3 is a schematic configuration diagram of the fixing device.
FIG. 4 is a chart showing sizes of various recording media.
FIG. 5 is a diagram showing a correspondence relationship between each peeling claw and the recording medium of the recording medium peeling apparatus according to the first embodiment.
FIG. 6 is a diagram illustrating a correspondence relationship between the peeling claw and an image forming area of a recording medium.
FIG. 7 is a perspective view of the periphery of a recording medium peeling device of a fixing device according to a second embodiment of the present invention.
FIG. 8 is a perspective view of the periphery of a recording medium peeling device of a fixing device according to a third embodiment of the present invention.
FIG. 9 is a plan view of a recording medium peeling apparatus according to a fourth embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Heating roller 2 Pressure roller 3 Pulling roller 4 Pressure belt 5 Heat source 6, 6a-6d Peeling claw 6e Common peeling claw 7 Thermistor 8 Toner image 9, 9a-9d Recording medium 10 Fixing device 11 Intermediate transfer device 12 Photosensitive device 13 Transfer device 14 Separation device 15 Intermediate transfer device cleaning means 16 Charger 17 Photoconductor cleaning means 18 Residual image removal means 19K, 19Y, 19M, 19C Developer 20 Exposure means 21 Recording medium holding means 22 Recording medium supply apparatus 23 Recording medium discharge Device 24 Recording medium peeling device 25, 25a to 25d Claw tip portion 26 Image forming region 27 Connecting portion 60 Shaft O Fixing outlet portion P Heating roller rotational direction Q Pressure belt traveling direction R Recording medium traveling direction T1 First transfer position T2 First Second transfer position W1 Separation claw inner distance W2 Image formation area width W3 Recording medium width

Claims (6)

In a recording medium peeling apparatus for forcibly peeling a recording medium on which a toner image is fixed by thermocompression from a rotating heating member,
Corresponding to the size in the width direction of the plurality of types of the recording media to be used, a plurality of peeling claws are supported on the shaft in pairs on the left and right sides at predetermined intervals along the width direction of the heating member,
The interval W1 inside the peeling claw in each pair is wider than the lateral width W2 of the image forming area on the recording medium to be peeled, and narrower than the lateral width W3 of the recording medium (W2 <W1 <W3). It is set individually for each pair of peeling nails,
In addition, the position of the claw tip of each peeling claw is set so as to be gradually away from the fixing outlet of the recording medium along the peeling claw on the inner side in the width direction from the peeling claw on the outer side in the width direction of the shaft. By
A recording medium peeling apparatus, wherein a recording medium of each size is peeled only by a pair of peeling claws corresponding to the size . 2. The recording medium peeling apparatus according to claim 1, wherein the peeling inclination angle of each peeling claw decreases in order from the peeling claw on the outer side in the width direction of the shaft along the peeling claw on the inner side in the width direction. A recording medium peeling apparatus. In the recording medium peeling apparatus according to claim 1 or claim 2, wherein the separation claws recording medium peeling apparatus characterized by being formed integrally. 4. A fixing device , wherein the recording medium peeling device according to claim 1 is disposed at a position where the recording medium coming out of the fixing outlet portion is peeled off from the heating member . The fixing device according to claim 4, wherein a part of the pressure belt is wound around a part of the heating member, and a fixing outlet portion of the fixing device presses the recording medium to the heating member side by the pressure belt. A fixing device , wherein the recording medium peeling device is disposed in the vicinity . An electrophotographic apparatus using the fixing device according to claim 4 .

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