JP2002189375A - Image recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device with a cleaning means to clean up an offset toner and paper dust on a fixing roller by a relatively small and simple constitution. SOLUTION: In the fixing device with a fixing roller, a pressing roller which comes into pressure contact with the fixing roller and a cleaning means to clean up foreign matter sticking to the surface of the fixing roller, a cleaning roller obtained by coating a metallic shaft with a heat resistant artificial leather having <=10 mm surface roughness Ra is used as the cleaning means. An artificial leather comprising polyethylene terephthalate and polyurethane is particularly used as the above artificial leather. A heat- and pressure-treated artificial leather is also used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image recording apparatus.

[0002]

2. Description of the Related Art Conventionally, an electrophotographic image recording apparatus has
A fixing roller and a pressure roller that is in pressure contact with the fixing roller are provided. At least the fixing roller is heated by a heater or the like, and the final recording medium such as paper is conveyed while being nipped between the fixing roller and the pressure roller. It has a configuration in which the toner image on the recording medium is melted and fixed on the final recording medium.

In such a fixing device, a part of the toner image on the final recording medium is usually transferred to the fixing roller. This is called offset, and the toner transferred to the fixing roller is called offset toner. Further, when the final recording medium is paper, a small amount of paper dust usually adheres to the fixing roller. In order to suppress the adhesion of the offset toner and paper powder to the fixing roller, a material having good releasability is selected as a material of the fixing roller, or silicone oil or the like is applied to the surface of the fixing roller to improve the releasability. It is generally done.

However, it is difficult to completely prevent the offset toner and the paper dust from adhering to the fixing roller by such means, and a small amount of the offset toner and the paper dust remain on the fixing roller. As a result, there arises a problem that the fixing roller or the pressure roller is stained or re-transferred onto the final recording medium to deteriorate image quality.

In order to solve such a problem, there has been proposed a mechanism provided with a cleaning means for cleaning offset toner and paper dust offset on the fixing roller.
For example, a mechanism that presses a cloth-like cleaning unit against the fixing roller to clean offset toner and paper dust on the fixing roller,
A mechanism that abuts the brush roller against the fixing roller to scrape off the offset toner and paper dust. Further, there is a mechanism for cleaning the offset toner and paper dust on the fixing roller by bringing the metal roller into contact with the fixing roller.

[0006]

In the above-mentioned prior art, in the case of a mechanism for cleaning the offset toner and paper dust on the fixing roller by pressing the cloth-like cleaning means against the fixing roller, the portion contaminated by the cleaning is removed. For example, in order to keep the clean surface in contact with the fixing roller by frequent replacement, it is necessary to use a so-called web type, for example, a winding type. There is a problem of growing.

In the case of a mechanism in which a brush roller is brought into contact with a fixing roller to scrape off offset toner and paper dust,
Since the offset toner and paper dust accumulate, there is a problem in life. In the case of a mechanism for cleaning the offset toner and paper dust on the fixing roller by bringing the metal roller into contact with the fixing roller, it is necessary to contact the metal roller with a blade or roller for further removing dirt.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide an image recording apparatus having a fixing device provided with a cleaning means for cleaning offset toner and paper dust on a fixing roller with a relatively small and simple configuration. Is to provide.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a fixing apparatus having a fixing roller, a pressing roller which presses against the fixing roller, and a cleaning means for cleaning foreign substances adhering to the surface of the fixing roller. Indicates that the metal shaft has a surface roughness Ra
This is achieved by a cleaning roller coated with a heat-resistant artificial leather of 10 mm or less.

Further, the heat-resistant artificial leather coated on the cleaning roller is achieved by being an artificial leather made of polyethylene terephthalate and polyurethane.

Further, the heat-resistant artificial leather coated on the cleaning roller is achieved by heating and pressurizing.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of a fixing device according to the present invention will be described with reference to FIG. In FIG. 1, reference numeral 14 denotes a fixing device, and a fixing roller 101 and a pressure roller 102 are arranged in pressure contact with each other. The fixing roller 101 and the pressure roller 102 have a configuration in which a rubber layer 113 made of, for example, silicon rubber is provided on the outer surface of a hollow metal core 112, and a heater 111 is built in the hollow portion.

A releasing agent supplying device 103 which comes into contact with the fixing roller 101, a scraping blade 104 for scraping off excess releasing agent and forming a releasing agent layer having a desired thickness on the surface of the fixing roller 101, And a cleaning roller 106 as cleaning means. The cleaning roller 106 is a metallic shaft 114
Is covered with a heat-resistant artificial leather 115. Further, a guide 105 is provided for correctly guiding the final recording medium 16 between the fixing roller 101 and the pressure roller 102.

The surface of the rubber layer 113 of the fixing roller 101 and the pressure roller 102 is heated to a desired temperature range by a heater 111 and driven by a driving device (not shown) while being pressed against each other, so that final recording is performed in the transport direction. It is rotating in a direction to transport the medium 16. With the rotation, the release agent is supplied to the surface of the fixing roller 101 from the release agent supply device 103, and the excess release agent is scraped off by the scraping blade 104, thereby forming a release agent layer having a desired thickness. You. The final recording medium 16 is guided by a guide 105 and passes through a portion where the fixing roller 101 and the pressure roller 102 are pressed against each other (hereinafter, this portion is referred to as a nip). The unfixed toner 17 on the final recording medium 16 receives heat from the rubber layer 113 while passing through the nip, and
6 Fixation on the top is performed.

When the unfixed toner 17 on the final recording medium 16 melts at the nip, the unfixed toner 17 and the final recording medium 16
When the adhesive force between the unfixed toner 17 and the fixing roller 101 is larger than the adhesive force between the unfixed toner 17 and the fixing roller 101, transfer and adhesion of the toner onto the fixing roller 101 occur. This is called an offset, and the toner transferred and attached to the fixing roller 101 is called an offset toner (not shown). When the final recording medium 16 is paper in particular, a slight amount of paper dust (not shown) exists on the surface thereof,
When the paper passes through the nip, part of the paper is transferred and adheres to the fixing roller 101.

When the offset toner (or paper dust) is left unattended, the offset toner (or paper dust) is re-transferred and adheres to the final recording medium 16 from the fixing roller 101, deteriorating the image quality of the final recording medium 16. The fixing roller 101 and the scraping blade 104 to damage the surface of the fixing roller 101, and in some cases, the role of an adhesive in which the offset toner adheres the fixing roller 101 to the final recording medium 16. In such a case, the final recording medium 16 may be wound around the fixing roller 101 in order to perform the above-described operations.

As means for avoiding this, as described above, the release agent is supplied from the release agent supply device 103 onto the fixing roller 101 to improve the releasability of the fixing roller with respect to the toner. It is difficult to completely prevent such a phenomenon and to completely prevent a minute amount of offset toner and paper dust from adhering to the fixing roller. Therefore, in order to remove the offset toner and paper dust adhered on the fixing roller 101, the fixing roller
A cleaning roller 106, which is a cleaning unit, is provided in contact with the fixing roller 101, and rotates in the forward direction with the fixing roller 101. The surface of the fixing roller 101 is cleaned by transferring and attaching the offset toner and paper powder on the fixing roller 101 to the cleaning roller 106 having a lower releasability than the fixing roller 101.

Next, the cleaning roller 106 in the fixing device 14 of the present invention will be described. As described above, the cleaning roller 106 covers the heat-resistant artificial leather 115 around the metallic shaft 114. In detail, in this embodiment, as in the cleaning roller 106 shown in FIG. The metallic shaft 114 and the heat-resistant artificial leather 115 are bonded by a heat-resistant adhesive layer 116.

In FIG. 2, since the role of the adhesive layer 116 is to bond the metallic shaft 114 to the heat-resistant artificial leather 115, another heat-resistant artificial leather 115 is attached to the metallic shaft 114. The adhesive layer 116 is not always necessary if it can be covered by means.

The surface of the heat-resistant artificial leather 115 has a surface roughness Ra.
Is preferably 10 mm or less from the viewpoint of cleaning properties. This will be described with reference to FIGS.

FIG. 3 shows a case where a plurality of materials having different surface roughnesses Ra are used as the artificial leather 115.
It shows the result of performing a sensory evaluation by visual observation of the state of dirt on the surface. Here, the evaluation results are expressed in order of artificial leather having a more dirty surface, that is, artificial leather having higher cleaning properties, in order of younger numbers.
The third row shows the magnitude of each surface roughness Ra. As can be seen from the figure, the smaller the surface roughness Ra, the higher the cleaning property.

FIG. 4 shows a case where a plurality of materials having different surface roughnesses Ra are used as the artificial leather 115, and the magnitude of the surface roughness Ra is plotted on an A4 size sheet with the horizontal axis representing the magnitude of the surface roughness Ra. When printing is performed, the toner that is offset from the paper to the fixing roller 101 is offset to the pressure roller, and the toner is further offset to the back of the paper, causing toner contamination on the back of the paper (this is called back contamination). The vertical axis represents the number of sheets passed until the printing is completed. Since the value on the vertical axis changes depending on the type of image, its absolute value does not matter here, but as a tendency, the lower the surface roughness Ra, the harder it is to stain the back.

That is, it is understood that the cleaning property is high. In particular, when the surface roughness Ra is 10 mm or less, the cleaning property is improved.
mm, the surface area Ra of the artificial leather surface is set to 10 mm or less, so that the contact area between the offset toner and the artificial leather surface can be microscopically increased, and the offset can be reduced. This is because the average adhesive force between the toner and the artificial leather surface increases.

On the other hand, when the surface roughness Ra of the artificial leather surface is larger than 10 mm, it is considered that the contact area between the offset toner and the artificial leather is small and the amount of the toner that passes through the artificial leather increases. As described above, when evaluated in conjunction with the visual sensory evaluation shown in FIG. 3, it is preferable to use a material having a surface roughness Ra of 10 mm or less from the viewpoint of cleaning properties.

In this embodiment, artificial leather made of polyethylene terephthalate and polyurethane is used as the artificial leather 115. Furthermore, for example, by heating and pressurizing artificial leather made of polyethylene terephthalate and polyurethane having a surface roughness Ra of about 10 mm,
Although Ra can be processed to about 2 mm, as can be seen from FIGS. 3 and 4, this processing can improve the cleaning property. Therefore, it is preferable to heat and pressurize the heat-resistant artificial leather 115 in order to improve the cleaning property and realize uniform cleaning.

Next, the configuration of an image recording apparatus using the fixing device of the present invention will be described with reference to FIG. In FIG. 5, the photosensitive belt 2 is stretched in a vertical direction by a driving roller 22 and a driven roller 21. The driven roller 21 is a photosensitive belt
It also has the function of giving tension to 2. Further, the photoreceptor belt 2 is rotated at a predetermined speed counterclockwise in the figure by a driving device (not shown). Around the photoreceptor belt 2, an intermediate transfer member 3 is arranged in contact with the photoreceptor belt 2,
A charger 4 for charging the surface of the photoreceptor belt 2 substantially uniformly, and a charger 4 for exposing the surface of the photoreceptor belt 2 charged substantially uniformly to form an electrostatic latent image on the surface. An exposure device 5 is provided. Further, developing devices 61, 62, 63, and 64, each of which stores toner of four different colors, are provided with a photosensitive belt.
It is arranged to abut on the horizontal surface of 2.

A cassette 10 for storing a final recording medium 16 such as paper, and a final recording medium
The paper feed roller 11 for feeding the recording medium 16 and the registration roller 12 for correcting the attitude of the final recording medium 16 supplied from the cassette 10 by the paper feed roller 11 are provided. Further, a transfer roller 13 for transferring the toner image on the intermediate transfer member 3 to the final recording medium 16 is disposed in contact with the intermediate transfer member 3, and remains on the surface of the fixing device 14 and the photosensitive belt 2 of the present invention. An erase lamp 9 for removing charges, a blade 8 for removing remaining toner, a cleaner 15 for removing toner remaining on the surface of the intermediate transfer body 3 after transfer, and the like are provided.

Next, a method of forming a color image using the present apparatus will be described. After the power is turned on, when an image output signal is sent from an information processing device (not shown) to the image recording apparatus main body in the image output standby state, first, the charger 4 charges the surface of the photoreceptor belt 2 substantially uniformly. Subsequently, a laser beam is emitted from the exposure device 5 in accordance with the image output signal, and an electrostatic latent image is formed on the photosensitive belt 2. At this time, first, an electrostatic latent image corresponding to the cyan toner image is formed on the photoreceptor belt 2 by the exposure device 5, and is developed by the cyan developing device 61 to obtain a toner image on the photoreceptor belt. The toner image formed on the photoreceptor belt 2 is transferred to the surface of the intermediate transfer member 3 at a contact portion with the intermediate transfer member 3, and is held on the surface.

On the other hand, the charge remaining on the surface of the photoreceptor belt 2 after the transfer of the toner image is removed by an erase lamp 9, and the remaining toner not transferred is removed by a blade 8. After the surface of the photoreceptor belt 2 returns to the initial state in this way, magenta, yellow, and black toner images of the next color and subsequent colors are similarly formed on the surface of the photoreceptor belt 2 by the same process, respectively. The image is superimposed and transferred on the toner image up to the previous color held on the surface of the transfer body 3, and the four color toner images are superimposed and held on the intermediate transfer body 3. Here, 61 is a developing device using cyan toner, 62 is a developing device using magenta toner, 63 is a developing device using yellow toner, and 64 is a developing device using black toner. Each developing unit can impart or eliminate a developing function by controlling a bias voltage.

Next, the transport mechanism of the final recording medium for transferring the four-color toner image formed on the surface of the intermediate transfer member 3 onto the final recording medium 16 will be described. First, the paper feed roller 11 is rotated, and the final recording media 16 stored in the cassette 10 are separated one by one and conveyed to the registration rollers 12. Correct the skew of the final recording medium 16 with the registration roller 12, and then rotate the registration roller 12 at a suitable timing to correctly transfer the four-color toner image on the intermediate transfer body 3 onto the final recording medium 16. Then, the final recording medium 16 is transported between the intermediate transfer body 3 and the transfer roller 13. The transfer roller 13 is moved from the back of the final recording medium 16 to the intermediate transfer
, And the four-color toner image formed on the surface of the intermediate transfer member 3 is electrostatically transferred onto the final recording medium 16 at one time.

The 4 transferred on the final recording medium 16 in this way
As described above, the color toner image is transferred to the fixing roller 10 of the fixing unit 14.
Fixing is performed when the sheet passes between 1 and the pressure roller 102, and a series of printing processes is completed.

As described above, according to the present invention, in a fixing device having a fixing roller, a pressure roller which presses against the fixing roller, and a cleaning means for cleaning foreign matter adhering to the surface of the fixing roller, By using a cleaning roller coated with a heat-resistant artificial leather having a metal shaft body having a surface roughness Ra of 10 mm or less, and in the invention according to claim 2, the cleaning roller coated with heat-resistant By making the artificial leather artificial leather made of polyethylene terephthalate and polyurethane,
Furthermore, in the invention according to claim 3, by heating and pressurizing the heat-resistant artificial leather coated on the cleaning roller, each of the above-mentioned problems of the prior art is solved, and the comparatively small size is achieved. With a simple configuration, it is possible to realize a fixing device including a cleaning unit that cleans offset toner and paper dust on the fixing roller.

[0033]

According to the present invention, it is possible to provide an image recording apparatus having a fixing device having a cleaning means for cleaning offset toner and paper dust on a fixing roller with a relatively small and simple structure.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a fixing device provided with the present invention.

FIG. 2 is a schematic sectional view of a cleaning roller in the fixing device of the present invention.

FIG. 3 is a table for explaining the relationship between the surface roughness Ra of the cleaning roller and the cleaning property.

FIG. 4 is a diagram for explaining the relationship between the surface roughness Ra of the cleaning roller and the cleaning property.

FIG. 5 is a schematic sectional view of an image recording apparatus provided with the fixing device of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Image recording device, 2 ... Photoreceptor belt, 3 ... Intermediate transfer member, 4 ... Charger, 5 ... Exposure device, 8 ... Blade, 9 ... Erase lamp, 10 ... Cassette, 11 ... Feed roller, 1
Reference numeral 2: registration roller, 13: transfer roller, 14: fixing device, 15: cleaner, 16: final recording medium, 17: unfixed toner, 21: driven roller, 22: drive roller, 61
... Developer using cyan toner, 62 ... Developer using magenta toner, 63 ... Developer using yellow toner, 64 ... Developer using black toner, 101 ... Fixing Roller, 102: pressure roller, 103: release agent supply device, 104: scraping blade, 105: guide, 106: cleaning roller, 1
11: heater, 112: metallic core, 113: rubber layer, 114: metallic shaft, 115: heat-resistant artificial leather, 116: heat-resistant adhesive layer.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshio Ogiso 502 Kandate-cho, Tsuchiura-city, Ibaraki Pref.Mechanical Research Laboratory, Inc. (72) Inventor Hiromitsu Fukuda 502-Kindachi-cho, Tsuchiura-City, Ibaraki Pref. Inside the Machinery Research Laboratory (72) Inventor Riki Hiraoka 1-1-1, Higashitaga-cho, Hitachi City, Ibaraki Prefecture Inside Hitachi Taga Electronics Co., Ltd. (72) Inventor Toru Hanajima 1-1-1 Higashitaga-cho, Hitachi City, Ibaraki Prefecture Incorporated Hitachi Tag Electronics Co., Ltd. (72) Inventor Katsuyoshi Onose 1-1-1, Higashitaga-machi, Hitachi City, Ibaraki Prefecture F-term in Hitachi Taga Electronics Co., Ltd. (reference) 2H033 AA08 BA25 BA49 BA54 BB01 B B28 3J103 AA02 AA13 FA07 GA54 HA04 HA41 HA48

Claims (3)

[Claims] 1. A fixing device comprising: a fixing roller; a pressure roller pressed against the fixing roller; and a cleaning unit for cleaning foreign matters adhering to the surface of the fixing roller. An image recording apparatus comprising a cleaning roller coated with a heat-resistant artificial leather having a Ra of 10 mm or less. 2. The heat-resistant artificial leather coated on the cleaning roller is an artificial leather made of polyethylene terephthalate and polyurethane.
The image recording device according to 1. 3. The image recording apparatus according to claim 1, wherein the heat-resistant artificial leather coated on the cleaning roller has been subjected to a heat and pressure treatment.