JP3065798B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

[0003]

2. Description of the Related Art Conventionally, a so-called heat roller fixing system is often used in a fixing device of an electrophotographic copying machine. In this method, a heating element such as an infrared light bulb is provided on one or both shaft portions of a roller having a surface coated with a non-adhesive substance, for example, a tetrafluoroethylene resin, a silicone rubber, a fluorocarbon resin, or the like. A shaft part between both rollers is rotatably supported by applying an appropriate pressure therebetween,
The recording material having unfixed thermoplastic powder (hereinafter referred to as toner) is allowed to pass between the two rollers.

That is, a conventional contact heating fixing device is shown in FIG.
And a pressure roller f formed by winding a heat-resistant elastic body e around a metal axis d, and a heating roller c having a non-adhesive coating b on the surface of a metal core a as shown in FIG.
A heating element g is provided inside the heating roller c. The rollers c and f cooperate with each other by a mechanism (not shown) to contact the recording material h supporting the toner image i while applying pressure to the recording material h, and to separate them during a waiting time or the like.

When the recording material h passes between the rollers c and f, the unfixed toner image i becomes a fixed image j.
In FIG. 7, k is an element for detecting the temperature of the heating roller c. The heating element is controlled by a control circuit (not shown) so that the temperature of the heating roller c becomes constant based on the temperature detected by the element k. It controls the input to g.

The heater roller fixing system has excellent advantages such as operation at relatively low power and no danger of fire, but it has the advantages that both rollers c and c can achieve good fixing.
The relationship of temperature, pressure, paper feed speed, etc. of f is limited,
If it is deviated, problems such as so-called offset adhesion of the toner to the heat roller and unfixing are likely to occur. To prevent this, a highly accurate temperature control is required. In addition, this method requires an offset toner cleaning device. As this cleaning device, a web cleaning device in which a heat-resistant nonwoven fabric is impregnated with silicone oil is generally used.

In order to prevent offset to the surface of the fixing roller, a web is arranged on a surface of a sponge or the like,
There is a device in which an application roller in which oil is applied to a sponge is rotated on the surface of a fixing roller. Further, there is an apparatus having an oil storage section inside the application roller and extending the life by gradually leaching oil from a hole provided in the storage section.

[0008]

However, according to each of the above conventional examples, there are the following problems. First, according to the conventional example shown in FIG. 7, not only the occurrence of offset, but also a number of failures such as a flaw of a roller, a malfunction of a cleaning device, or a contact failure of a separation claw or a thermistor may occur. Since a failure could not be detected, there was a problem that a fixing failure or an accident occurred.

[0009]

[0010]

An object of the present invention is to solve the above-mentioned problems and to provide a simple
An object of the present invention is to provide an image forming apparatus having a simple configuration and capable of detecting a failure of each unit and device provided in a fixing device.

[0012]

[0013]

[0014]

According to the present invention, the above object is achieved by detecting means for reading a document image,
Unfixed to form an unfixed image on the recording material based on the output of
An image forming unit and an unfixed image forming unit.
A fixing roller pair for fixing the unfixed image on the recording material ,
In the image forming apparatus having a contact member for the release agent application to the cleaning or roller surface in contact with at least one roller of the constant wear rollers Russia <br/> over la surface,
The detecting means further detects a surface state of the contact member ,
Is accomplished by determining the malfunction of the peripheral members abutting the surface state or roller groups Dzu-out the roller to the output from said detecting means.

[0015]

[0016]

[0017]

In the present invention, a contact member such as a cleaning means is disposed on at least one of the fixing roller pairs so as to rub against the surface of the roller. A predetermined pattern or a locus reflecting the state of the roller surface is drawn. Also scans the original image
Detection means further detects the surface condition of the contact member
It is, therefore, the state of the surface of the contact member
By optically detected by said detecting means, to determine the failure of the abutting peripheral members from the state of the surface to scratches or generation or the roller surface of the offset of the roller surface, prevent fixing failure or accident I do.

[0018]

[0019]

[0020]

An embodiment of the present invention will be described with reference to the drawings.

First, an embodiment of the present invention will be described with reference to FIGS. In the present embodiment, the movement of the offset and separation claws, the roller flaw, and the like are detected by detecting the contamination state of the cleaning web.

FIG. 1 is a schematic sectional view of the apparatus of this embodiment. In FIG. 1, reference numeral 1 denotes a platen glass on which a document or the like is placed, 2 denotes an illumination lamp (exposure lamp) for irradiating the document,
Reference numerals 3, 4, and 5 denote scanning reflection mirrors (scanning mirrors) for changing the optical path of the reflected light of the original, 6 denotes a lens for focusing, 7
Denotes a light receiving element, and the light receiving element 7 converts a document image into an electric signal. Reference numeral 8 denotes a photosensitive drum, 9 denotes a developing device, 10 denotes a transfer charger, 11 denotes a separation charger, and 12 denotes a cleaning device. Reference numeral 13 denotes a primary charger, 14 denotes a laser exposure system, and 15 denotes a return mirror. 16
Denotes an upper paper cassette, and 17 denotes a lower paper cassette. 1
8, 18 'are paper pickup rollers, 19, 19' are paper feed rollers, and 20, 20 'are retard rollers. 2
Reference numerals 1 and 22 denote transport belts each having a suction fan therein. Reference numeral 23 denotes a fixing entrance guide. 24 is a heating roller, 25 is a pressure roller, 26 is a cleaning web, 2
Reference numerals 7 and 28 denote separation claws. Reference numeral 29 denotes a document feeder and paper discharge tray.

In the apparatus of the embodiment described above, the original image on the original platen glass 1 is read by the light receiving element 7 while being scanned by the moving optical system, and is converted into an electric signal. After performing various signal processings on the electric signal, a drive signal is sent to the laser of the scanning laser exposure system 14 based on the signal to form a latent image on the photosensitive drum 8. This latent image is developed by the developing device 9 to form an image on the photosensitive drum 8. On the other hand, paper is transferred from the upper paper cassette 16 onto the transfer charger 10,
The toner image on the photosensitive drum 8 is transferred onto the paper. Next, the paper is separated from the photosensitive drum 8 by passing through the charge removing corona of the separation charger 11, and is fed by the conveyor belt 21.
Then, the paper is carried upward while being sucked by the vertical transport belt 22, and is fixed along the entrance guide 23 by passing through the nip portion between the heating roller 24 and the pressure roller 25.

FIG. 2 is an enlarged view of the fixing section of the image forming apparatus. As shown in FIG. 2, the heating roller 24 has a silicone rubber layer 24-2 on an aluminum core 24-1.
A release layer 24-3 is provided thereon as a thin layer having a thickness of about 0 μm. The pressure roller 25 is provided with a silicone rubber layer 25-2 of about 5 mm on the core metal 25-1, and further covered with a release layer 25-3. Further, halogen heaters 29 and 30 are arranged in the heating roller 24. Further, the pressure roller 25 is rotated in a direction indicated by an arrow by a driving means (not shown), and is driven to rotate. Separating claw 27,2
Reference numeral 8 denotes a heat-resistant resin coated with a material having good releasability, for example, a fluororesin. FIG.
Reference numerals 31 and 32 denote paper discharge rollers. 33 is a temperature sensing element for detecting the surface temperature of the heating roller. The web 26 is pressed against the heating roller 24 by a web pressing roller 34 to perform oil application and cleaning. After passing through the relay rollers 35 and 36, the web take-up shaft 3
7 is wound up. The toner indicated by T is the toner adhered to the web after cleaning, and when the amount of the offset toner is large, the amount of the adhered toner increases. The cleaning web is a heat-resistant non-woven cloth, has sufficient strength even if it is sufficiently thin, and the presence or absence of toner can be sufficiently observed even when the non-woven cloth is observed from the back.

FIG. 3 is a view of the separation claw 28 viewed from the direction of arrow A in FIG. (A) is a diagram in which the separation claw is shifted to the left end, and (b) is a diagram in which the separation claw is shifted to the right end. In FIG. 3, reference numeral 38 denotes a sheet metal to which the separation claw 28 and the claw holder 28a are attached.
Slowly reciprocate left and right with 9. As a result, wear of the roller 24 due to the claw is reduced, and the life is extended.

FIG. 4 shows a state when the stain state of the web 24 is observed. The zigzag patterns shown in (a) and (b) indicate that the separation claw is reciprocating. That is, the offset toner of the heating roller 24 is scraped by the separation claw 28 and the cleaning web is not stained at a portion where the separation claw 28 exists. And separation claw 2
When the reciprocating operation is normally performed, the pattern 8 has a zigzag pattern. Parts (c) and (d) in FIG. 4A show a state where the reciprocating operation has been stopped.
The portion indicated by (e) indicates that the paper size has become smaller and the width of dirt has become narrower.

Next, the portion indicated by (f) in FIG.
This indicates that the release layer on the surface layer of the heating roller was peeled off by the separation claw. In other words, this indicates that the release layer has peeled off, the amount of offset toner to the roller has increased, and the web has been rapidly soiled. Further, FIG. 4C shows that the web is very dirty at the portion (G). In such a case, the web is not normally fed and the web is stopped. Alternatively, even if there is any cause, such as a poor pressurization or a decrease in temperature, such rapid contamination occurs.
Further, the end mark (h) is a mark for detecting the web feeding state. If the web drive is performed while detecting this mark, a failure such as a stop of the web is prevented, and the web drive is prevented. Can be distinguished from an increase in offset due to some cause.

As described above, by observing the soiling state of the web, it is possible to determine a substantial part of the failure in the fixing unit. In the present invention, a normal fixing unit is arranged upside down so that the fixing web can be observed from the document table portion, and the web is detected by a light receiving element for reading the document.

The detection of the stain state of the web is performed by, for example,
The scanning optical system groups 2, 3, 4, and 5 move below the web every 2000 copies, and read the web portion. The read image information is recorded in the memory. Abnormality detection is performed while comparing this image information with a predetermined reference pattern. This can be easily achieved by using, for example, an image processing apparatus disclosed in JP-A-59-64855 or the like, so that the details of the configuration and method are omitted.

By detecting the zigzag pattern, normal or abnormal nail reciprocating operation is detected. Then, when a black streak having a width of about the nail is detected in the nail reciprocating range, this is detected as a roller nail scratch. Further, when a difference between the reference pattern and the reference pattern is obtained in the central paper passage area, if the black image is dark over a certain width, it is detected as fixing and offset abnormality. When observing the soiling of the web,
Originally, it is desirable to observe web dirt immediately after leaving the web pressing roller. Then, at the time of observation, the take-up roller 37 once takes up the web at the nip portion between the web pressing roller 34 and the heating roller 24 so as to come to the document table. After the operation of the exposure scanning system for observing the web surface, the web delivery roller 26 is again rotated in reverse to rewind the web. In this way, it is possible to find a failure of the fixing device without time delay.

< Reference Example 1 > Next, Reference Example 1 according to the present invention will be described with reference to FIG. Note that the same parts as those in the embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0032] In the embodiment, by mounting the fixing unit on the platen on has been detected web dirt present embodiment, as shown in FIG. 5, it is prepared by attaching the web contamination detection device independently. The parts indicated by 24 to 37 in FIG. 5 are the same as those in the embodiment of FIG. Further, the position at which the fixing device is disposed is not limited to the position on the document table shown in the embodiment, and is not limited.

The present embodiment, the temperature in the upper cleaning web 26 around the heating roller 24 has adopted a method of observing the web surface with a glass fiber for a high temperature. In FIG. 5, reference numerals 38 and 39 denote glass optical fiber bundles. The light of the lamp 40 is collected by the condensing reflector 41, the direction of the light is changed by the reflector 42, and the light is diffused by the diffuser 43. Uniform light is applied to each fiber.
The optical fibers 38 are aligned in one or two rows in the longitudinal direction of the roller at a portion 45 so as to uniformly illuminate the web in the longitudinal direction. The reflected light from the web illuminated by the 45 optical fiber rows is guided from the 46 optical fiber rows to a light receiving element row (CCD line sensor) 47. This makes it possible to detect contamination of the toner on the web surface. Reference numeral 44 denotes a rotating shaft for changing the direction of the fiber array, which is rotatable by a rotation driving means (not shown), so that the heating roller surface can be observed in addition to the web surface. Reference numeral 47 denotes a standard white plate for correcting variations in the transmittance of the optical fiber, the sensitivity of the line sensor, and the like, and for uniforming the detection sensitivity in the longitudinal direction.

In order to detect the stain on the web surface,
First, an encoder (not shown) for detecting a rotation angle is attached to the web pressing roller, and the lamp 40 emits light based on a signal of the rotation angle.
Then, detection of web contamination is performed by the standard white plate 47.
By recording this as one line in the memory, it is possible to record an image of a web stained state as in the first embodiment. Based on this image, reciprocating failure and fixing failure are detected in the same manner as in the first embodiment. Further, the roller surface is directly observed to detect density unevenness on the roller surface in the longitudinal direction, and to detect roller flaws and roller contamination.

[0035] <Reference Example 2> Next, a reference example 2 related to the present invention will be described with reference to FIG. Note that the same parts as those in the embodiment and Reference Example 1 are denoted by the same reference numerals, and description thereof will be omitted.

In the above embodiment and Reference Example 1 ,
An example of a fixing device using web cleaning was shown,
Even in a fixing device using a felt roller, a cleaning rubber roller, or the like, the abnormality can be detected and the cause thereof can be estimated. FIG. 6 shows an example in which a felt roller is used for cleaning. In FIG. 6, reference numeral 50 denotes a felt roller, which has a configuration in which a core bar is covered with a silicone sponge layer impregnated with silicone oil, and a heat-resistant felt layer is coated thereon. Performs oil application and cleaning. When the fixing condition is poor, the felt easily becomes dirty immediately, and the oil discharge is deteriorated. Further, when this felt roller cleaning system is used, the cleaning ability is inferior to that of the web, so that the heating roller 24 is easily stained, and if the roller staining becomes worse, paper wrapping may occur at the fixing unit. Therefore, a graph of the dirt on the felt roller and the number of durable sheets is made, and if the dirt on the felt roller is equal to or more than the reference value after a certain number of sheets, it is determined that there is abnormality. Also, by detecting the color change due to the adhesion of the toner on the heating roller surface,
Before the paper is wound, replacement and cleaning of the roller can be prompted.

In a low-cost machine using a felt roller, an optical fiber is scanned slowly mechanically in the longitudinal direction of the roller with one optical fiber and a light receiving element without using an optical fiber array. You may take the method.

[0038]

[0039]

[0040]

[0041]

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048]

[0049]

[0050]

[0051]

[0052]

[0053]

[0054]

[0055]

[0056]

[0057]

[0058]

[0059]

[0060]

[0061]

As described above, according to the present invention,
By detecting means for reading an original image, it can also detect surface conditions of the contact member such as a cleaning device and an oil applying device
Runode, without complicating the device configuration, the cause of the failure of easily fixing device can be quickly estimated detection.

[0062]

[0063]

[Brief description of the drawings]

FIG. 1 is a sectional view showing a schematic configuration of an apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a schematic configuration of a fixing device in the apparatus of FIG. 1;

FIG. 3 is a view showing the vicinity of a separation claw mounting portion in the apparatus of FIG. 2;

FIG. 4 is a diagram showing a relationship between a soiled state of a web and a failure state of each means in the apparatus in FIG. 2;

5 is a diagram showing a schematic configuration of Example 1 according to the present invention.

6 is a diagram showing a schematic configuration of Example 2 according to the present invention.

FIG. 7 is a cross-sectional view illustrating a schematic configuration of a conventional fixing device.

[Explanation of symbols]

 24 Heating roller (fixing roller) 25 Pressure roller (fixing roller) 26 Cleaning web (contact member)

Continued on the front page (72) Inventor Takayuki Ishihara Canon 30-2, Shimomaruko 3-chome, Ota-ku, Tokyo (72) Inventor Chief Tanaka 3-2-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Shinji Hanada 3-2-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (56) References JP-A-4-140780 (JP, A) JP-A-53-144342 (JP, A) ) Japanese Utility Model Showa 61-104469 (JP, U) Japanese Utility Model Showa 59-33619 (JP, Y2) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 13/20 G03G 15/20

Claims (2)

(57) [Claims] A detecting means for reading a document image;
Forming an unfixed image on the recording material based on the output from the
Unfixed image forming means, and the unfixed image forming means
Abutting performing an unfixed image formed with the fixing roller pair for fixing on the recording material, a release agent application to the cleaning or roller surface of the contact to the roller surface on at least one of the rollers of the constant wear rollers in the image forming apparatus having the member, the detecting means further detects the surface state of the contact member, malfunction of the peripheral members abutting the surface state or roller groups Dzu the output-out the roller from said detecting means An image forming apparatus characterized in that: Wherein said contact member is an image forming apparatus according to claim 1, characterized in that the cleaning web.