JP2006178309A - Fixing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a belt fixing device having a belt meandering control mechanism and capable of preventing the damage of a belt itself or a belt detection means even if the reciprocation of the belt in a fixed range is impossible because a belt meandering reciprocating condition is spoiled. <P>SOLUTION: In the fixing device, an image is thermally fixed by making recording material pass through a nip part. When the meandering of the belt is detected by a meandering detection sensor in the midst of image forming processing, the image forming processing is temporarily interrupted and the belt meandering moving motion is controlled in a state where the belt is separated by an attaching/detaching mechanism. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to control of a fixing device such as an electrophotographic apparatus, a copying machine, or a printer using a Carlson process.

  Conventionally, in an electrophotographic system, a toner image as a developer image is formed on a recording material such as paper by a method called a Carlson process, and then the toner image is fixed as a permanent image. Various fixing methods have been proposed for this purpose, but a method of fixing a toner image by heating and pressurizing (hot pressure fixing method) is generally used from the viewpoint of fixing properties, and a heating source is included. In many cases, a toner image is directly brought into contact with and fixed to a pair of rotating bodies.

  FIG. 2 shows a general roller type fixing device (hereinafter referred to as roller fixing).

  In FIG. 2, 1 is a fixing roller and 2 is a pressure roller. The fixing roller 1 and the pressure roller 2 are coated with an elastic layer 4 such as silicon rubber on a hollow metal core 3 made of a metal having a high thermal conductivity such as aluminum, and further, a fluorine coating layer 5 is coated on the surface layer as a release layer. It is a thing. The fixing roller 1 and the pressure roller 2 are pressed against each other at a constant pressure by a pressure mechanism (not shown), and an area (generally a fixing nip and a fixing nip) formed by the distortion of the elastic layers of both rollers. Called) is formed. The fixing roller 1 is rotationally driven by a driving device (not shown), and at the same time, the pressure roller 2 is driven by a frictional force with the fixing roller 1. When the unfixed toner image passes through the fixing nip, the toner is melted by heat and pressure, and is fixed by natural cooling after passing through the nip. A halogen lamp 6 is disposed inside the fixing roller 1 as a heating source, and is adjusted to a certain temperature by a temperature control circuit (not shown) based on the output result of the thermistor 7 that detects the surface temperature of the fixing roller.

  Here, the amount of heat applied to the recording material on which the unfixed toner image is placed depends on the temperature of the fixing roller and the pressure roller, the time for the recording material to pass through the fixing nip, that is, the fixing nip width and the recording material traveling speed. It turns out that it depends. Here, the fixing nip width refers to the length of the fixing nip in the recording material traveling direction.

  That is, an electrophotographic apparatus having a higher process speed requires a fixing apparatus having a wider fixing nip corresponding to the electrophotographic apparatus, and in order to realize this, in Patent Document 1, a belt-type hot-pressure fixing apparatus is used. So-called belt fixing has been proposed.

  In the belt fixing described above, the belt moves in the width direction (direction perpendicular to the belt rotation conveyance direction) along the length of the belt conveyance path member in the belt rotation conveyance process. Actions are taken to regulate movement.

  As the shift movement restricting means, the belt is made of a thin film and the material is elastic, for example, by restricting with a rib or a flange member, or by making the belt suspension conveying roller as a belt conveying path member into a clan shape, for example. In the case of a small amount of polyimide or the like, it is difficult to restrict the movement of the belt, and it is difficult to ensure stable rotation and conveyance of the belt.

  Therefore, a means for detecting the belt shift position is provided, and when it is detected that the shift of the belt toward one side in the width direction has reached a predetermined limit position, the belt shift that is the return direction of the belt shift is detected. The belt conveying path member, for example, a means for displacing the belt suspension conveying roller is operated so as to change the direction to the other side, and conversely, the movement of the belt toward the other side in the width direction has reached a predetermined limit position. If detected, by providing a belt shift movement forming mechanism configured to actuate a means for displacing the belt suspension conveying roller so as to change the belt shift movement to one side in the belt width direction which is the return direction. A belt shift movement control mechanism is used in which the shift movement movement in the belt width direction during the rotational conveyance process is changed to an infinite reciprocation movement within a predetermined range (Patent Document 2).

JP 61-132972 A Japanese Patent Laid-Open No. 02-010186

  However, the above prior art has the following problems.

  The belt shift movement control mechanism switches the belt shift direction between the forward and reverse directions under a certain condition. In the initial state, the belt shift movement control is performed by some degree of component accuracy or initial adjustment. However, when some external factor is applied, the belt does not move in the specified direction even if the belt conveyance path member is displaced. The belt may move closer.

  As the external factor, first, the influence of the fixing roller can be cited. In belt fixing, since the nip width is wide, that is, the pressure contact area between the fixing roller and the belt is large, the deviation control reciprocation condition may be lost due to distortion of the fixing roller itself or displacement of the fixing roller and the belt in the rotational conveyance direction. is there.

  In general belt (film) conveyance, it is not necessary to consider an extreme temperature difference. However, since the target device in the present invention is a fixing device, the temperature of each component rises to about 150 to 200 ° C. in a temperature rising state. To do. As the temperature rises, the friction coefficient of the belt conveyance path member and the fixing roller naturally changes (generally becomes smaller), so the initial belt shift control reciprocating condition may be lost.

  Furthermore, due to durability, the friction coefficient changes due to wear of the belt inner surface, the belt conveying means, and the fixing roller surface is also a factor that fluctuates the belt shifting condition.

  If the belt offset control reciprocating condition is broken due to the above external factors and the belt cannot reciprocate within a certain range, it naturally leads to troubles such as damage to the belt itself or the belt detecting means, for example, the photo sensor.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a belt fixing device having a belt shift control mechanism, the belt shift reciprocation condition is broken, and the belt reciprocation within a certain range. Even if it cannot move, it is possible to prevent the belt itself and the belt detecting means from being damaged.

  In order to achieve the above object, the invention described in claim 1 includes a rotating body having a heating source, a rotatable belt that presses against the rotating body and forms a nip for nipping and conveying a recording material, and the rotating body. And a demounting mechanism for contacting and separating the belt from the belt, and a belt width direction as a direction perpendicular to the belt rotation direction, and a shift for controlling the movement movement toward the belt width during rotation of the belt. In a fixing device having a control roller and a shift detection sensor capable of detecting the shift movement, and fixing the image by heat by passing a recording material through the nip portion, the shift detection sensor during image forming processing When the deviation of the belt is detected, the image forming process is temporarily interrupted, the belt is separated by the detaching mechanism, and the movement movement of the belt is controlled. To.

  A second aspect of the invention relates to the fixing device according to the first aspect, wherein the image forming process is resumed when the deviation of the belt returns during the interruption of the image forming process.

  According to the present invention, during the image forming process, the belt reciprocating motion condition collapses, so that the belt cannot reciprocate within a certain range, and the image forming process is temporarily performed even when the belt is deviated. By interrupting, separating the fixing roller and the belt, and performing belt deviation control without external factors such as the fixing roller and its heat, it is possible to reliably suppress belt deviation control within a certain range. As a result, it is possible to prevent the belt from being damaged, and to reduce the stop time of the apparatus due to the damage.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 3 is a cross-sectional view showing the configuration of the copying apparatus. The configuration and operation will be described with reference to FIG.

  An image forming apparatus 100 according to an embodiment of the present invention includes a document feeder 1000, an image reader 200, a printer 300, and a finisher 500.

  The above configuration and the operation will be described in detail. The document feeder 1000 conveys the set documents one by one from the top page in order from the left to the right on the platen glass 102 through the curved path, and then The paper is discharged to the paper discharge tray 112. At this time, the reader scanner unit 104 is held at a predetermined position, and the document is read by passing the document on the reader scanner unit 104 from left to right. When the original passes, the light from the lamp 103 of the reader scanner unit 104 is irradiated onto the original, and the reflected light from the original is guided to the image sensor 109 via the mirrors 105, 106, 107 and the lens 108. The original can be read by moving the reader scanner unit 104 from the left to the right by stopping it after the original is conveyed onto the platen glass 102 by the original feeder 1000. The document image read by the image sensor 109 is subjected to image processing and sent to the exposure control unit 110. The laser beam output by the exposure control unit 110 is applied to the photosensitive drum 111, and an electrostatic latent image is formed on the photosensitive drum 111. The electrostatic latent image on the photosensitive drum 111 is developed by the developing device 113, and the toner on the photosensitive drum 111 is transferred to a sheet fed from any of the cassettes 114 and 115, the manual paper feeding unit 125, and the double-sided conveyance path 124. Transferred by the part 116. The sheet onto which the toner has been transferred is subjected to toner fixing processing by the fixing unit 117.

  Details of the configuration of the fixing device 117 that is a feature of the present invention will be described later.

  The sheet that has passed through the fixing unit 117 is once guided to the path 122 by the flapper 121, the sheet is switched back after the trailing end of the sheet has passed through the flapper 121, and is guided to the discharge roller 118 by the flapper 121. As a result, the surface onto which the toner has been transferred is discharged from the printer 300 by the discharge roller 118 in a downward state (face down).

  When an image is formed on the hard sheet such as an OHP sheet from the manual sheet feeding unit 125, the surface onto which the toner is transferred is discharged from the discharge roller 118 in an upward state (face up) without being guided to the path 122. When forming an image on both sides of the sheet, the sheet is guided straight from the fixing unit 117 to the discharge roller 118, and the sheet is switched back immediately after the trailing edge of the sheet passes through the flapper 121. Guide to path 124. The sheet discharged from the discharge roller 118 is sent to the finisher main body 500. The finisher body 500 performs processing such as shift processing, binding processing, and hole punching. An inserter 1900 is provided on the finisher 500 and feeds a cover sheet, a slip sheet, and the like to the finisher main body 500. Further, the alignment plate 1702 moves to an angle perpendicular to the transport direction when discharging the recording material such as shift sorting, and discharges the recording material to the back or front of the tray 1701.

  Next, the operation panel (operation unit) will be described.

  FIG. 4 is a diagram illustrating a configuration of the operation panel 60 provided in the image forming apparatus. In FIG. 4, reference numeral 400 denotes a copy start key for instructing start of copying. Reference numeral 401 denotes a reset key for returning to the standard mode. Reference numeral 402 denotes a guidance key that is pressed when the guidance function is used. Reference numeral 403 denotes a numeric keypad for inputting a numerical value such as a set number of sheets. Reference numeral 404 denotes a clear key for clearing a numerical value. Reference numeral 405 denotes a stop key for stopping copying during continuous copying. Reference numeral 406 denotes a liquid crystal display unit and a touch panel for displaying various mode settings such as a staple mode, a bookbinding mode, and a double-sided print setting, and a printer status. Reference numeral 407 denotes an interrupt key for interrupting during continuous copying or during use as a fax or printer to take an emergency copy. Reference numeral 408 denotes a personal identification key for managing the number of copies by individual or department. Reference numeral 409 denotes a soft switch for turning on / off the power of the image forming apparatus main body. Reference numeral 410 denotes a function key used when changing the function of the image forming apparatus. Reference numeral 411 denotes a user mode key for entering a user mode in which a user sets items in advance, such as ON / OFF of an auto cassette change or a change of a set time until entering an energy saving mode.

  Next, the fixing device will be described.

  FIG. 1 is a schematic configuration diagram of a fixing device according to an embodiment of the present invention.

  In FIG. 1, reference numeral 1 denotes a fixing roller, in which a hollow cored bar 3 is covered with an elastic layer 4 such as silicon rubber, and a fluorine coating layer 5 is covered as a release layer on the surface layer. Inside the fixing roller 1, a halogen lamp 6 as a heating source is disposed.

  The thermistor 7 is in contact with the surface of the fixing roller 1 at the center of the sheet passing area at the center of the fixing device. The thermistor 7 sends the detected temperature to the temperature adjustment circuit 17 as an electrical signal. The temperature adjustment circuit 20 turns on / off the light emission of the halogen lamp 6 so that the surface of the fixing roller 1 becomes a predetermined constant temperature.

  A pressure belt 10 is formed by molding a heat-resistant resin material such as polyimide into an endless belt shape. The pressure belt 10 is stretched by 13, 14 stretching members and 15 shift control rollers. A pressure member 11 is formed by molding aluminum into a block shape, and forms a fixing nip portion by pressure contact. The fixing roller 1 is driven and rotated by a driving device (not shown), and the pressure belt 10 is rotated in accordance with the rotation. Further, a detaching means (not shown) for bringing the pressure belt 10 into and out of contact with the fixing roller 1 is provided, and is configured to freely swing in the direction of the arrow 16. Reference numerals 18 and 19 denote photosensors for detecting the belt position. The photosensor 18 is disposed closer to the belt than the photosensor 19. Similarly, photosensors 20 and 21 (FIG. 5) are arranged at positions facing the photosensors 18 and 19 across the belt, and the photosensor 20 is arranged at a position closer to the belt than the photosensor 21. Yes.

  FIG. 5 is a top plan view of the pressure belt 10 according to the embodiment of the present invention.

  The tension member 14 can be rotated by a belt drive motor 22, and the pressure belt 10 can be rotated even when it is separated from the fixing roller 1.

  Here, when the fixing belt 1 is driven in a state where the pressure belt 10 is pressed against the fixing roller 1 and the pressure belt 10 is driven to rotate, the stretching members 13 and 14, the shift control roller 15, and the fixing roller are driven. When the pressure belt 10 is rotated by the belt drive motor 22 with a parallelism of 1 (X axis, Y axis, Z axis) or spaced from the fixing roller 1, Unless the parallelism of the deviation control roller 15 is set to ± 0, the pressure belt 10 is displaced to the left (back side) or right (front side) along the longitudinal direction of the stretching members 13 and 14. As a result, the end of the belt rubs against the side plate 25 or 26 and is damaged.

  In this embodiment, the shift control roller 14 is configured to be freely swingable in the direction of the arrow 28 or 29 by the stepping motor 27 about the center 23 as an axis. When the stepping motor 27 rotates in the clockwise direction, the shift control roller 15 is displaced in the direction of the arrow 28 and counterclockwise, so that the displacement control roller 15 is displaced in the direction of the arrow 29. At this time, depending on the displacement direction of the shift control roller 15, the pressure belt 10 moves to the front side of the arrow P when displaced in the direction of the arrow 28, and moves to the arrow Q when displaced in the direction of the arrow 29. The leaning direction changes to the back side.

  The photosensors 18, 19, 20, and 21 are shielded from light by the pressure belt 10 itself when the pressure belt 10 approaches the arrow P or Q. Photosensors 18 and 20 indicate a shift of the pressure belt 10, and photosensors 19 and 21 indicate that a shift of the pressure belt 10 has occurred (Table 1).

以降、図６、７用いて、本発明を特徴づける定着制御に関して説明する。

Hereinafter, the fixing control characterizing the present invention will be described with reference to FIGS.

  FIG. 6 is a flowchart for controlling the shift of the pressure belt 10 in the present embodiment.

  When a job (copy or print) is started in S100, it waits for the photosensor 18 or 20 to be shielded from light in S101. If the light is not shielded, both photosensors are monitored repeatedly until the light is shielded. If the light is shielded, the position of the pressure belt 10 is determined from Table 1 in S102. When it is close to the front side (photo sensor 18: light shielding photo sensor 20: light transmission), the process proceeds to S103. When it is close to the rear side (photo sensor 18: light transmission photo sensor 20: light shielding), S110 is performed. Proceed to In S103, the stepping motor 27 is rotated counterclockwise, and the shift control roller 15 is displaced in the direction of the arrow 28. Subsequently, in S104, the output of the photosensor 18 is confirmed again. If light is transmitted (when the pressure belt 10 is returned), the process returns to S101. If the light is continuously shielded, the process proceeds to S105. In S105, it is confirmed whether or not the photosensor 19 is shielded from light. If it is shielded from light, it is determined that the pressure belt 10 has approached, and the process proceeds to S106.

  If the photo sensor 19 is transparent, the process returns to S104. In S106, it is determined whether or not the recording material is passing through the fixing device. If not, the process proceeds to S107. If the paper is being passed, the process waits in S106 until the paper passing is completed. Similarly, in step S108, the stepping motor 27 is rotated clockwise, and the shift control roller 15 is displaced in the direction of the arrow 29. Subsequently, in S109, it is confirmed again whether the photosensor 19 is shielded from light. If the light is transmitted, the process returns to S101. When the light is shielded, the process proceeds to S110. If the photosensor 21 is shielded from light in S110, that is, if it is determined that the pressure belt 10 is approaching, the process proceeds to S106 and S107. If the photosensor 20 is transparent, the process returns to S101.

  FIG. 7 is a flowchart from when the image generation process is suspended to when the process is suspended and then restarted.

  In S300, the job is temporarily suspended. In step S301, the pressure belt 10 is separated from the fixing roller 1 by using a detaching mechanism. In step S302, the driving of the belt driving motor 22 is started, and the shift control of the pressure belt 10 in the state of being separated from the fixing roller 1 is started. . In step S303, measurement of the timer Tcnt is started. In S304, the state of the pressure belt 10 is determined from the outputs of the photosensors 19 and 21, and it is determined in S305 whether or not the deviation has returned. If not, it is determined in S306 whether the predetermined time Tref has elapsed, and if it has elapsed, the job is completely interrupted in S307. If the predetermined time Tref has not elapsed, the process returns to S304. Although the predetermined time Tref in this embodiment is set in advance, it may be possible to change the predetermined time Tref using setting change means such as a user mode. If it is determined that the shift has returned in S305, the driving of the belt drive motor 22 is stopped in S308, the pressure belt 10 is again brought into pressure contact with the fixing roller in S309, and the job is restarted in S310. After restarting, the process returns to S101 or S201.

  As described above, when the deviation of the pressure belt 10 does not return within a predetermined time or when a deviation is detected, the job is once stopped and separated from the fixing roller 1, that is, the belt deviation does not return. By performing the shift control with the target factor reduced, the shift of the pressure belt 10 can be reliably returned, and the pressure belt 10 can be prevented from being damaged.

FIG. 2 is a schematic explanatory diagram of a fixing device in the present invention. It is a schematic explanatory drawing of the conventional roller fixing device. 1 is a cross-sectional view of a copying apparatus. It is an operation panel general-view figure. It is a top view top view of a pressure belt. It is a pressure belt shift control flowchart. It is a job resumption flowchart.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fixing roller 2 Pressure roller 6 Halogen lamp 7 Thermistor 10 Pressure belt 11 Pressure member 15 Shift control roller 17 Temperature adjustment circuit 18, 19, 20, 21 Photo sensor

Claims (2)

A rotating body having a heating source;
A rotatable belt that presses against the rotating body and forms a nip for nipping and conveying the recording material;
A desorption mechanism for contacting and separating the belt from the rotating body;
When the direction perpendicular to the rotation direction of the belt is the belt width direction,
A deviation control roller for controlling a deviation movement movement in the belt width direction while rotating the belt;
A deviation detection sensor capable of detecting the movement movement;
Have
In a fixing device that fixes an image by heat by passing a recording material through a nip portion,
When the deviation of the belt is detected by the deviation detection sensor during the image forming process,
A fixing device, wherein image forming processing is temporarily interrupted, and movement movement toward a belt is controlled in a state where the belt is separated by the detaching mechanism.   The fixing device according to claim 1, wherein the image forming process is resumed when the deviation of the belt returns during the interruption of the image forming process.

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