JP2007310076A - Fixing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problems in detecting jam of a paper sheet wound on a fixing roller in a fixing device, wherein when the paper sheet detection timing by a detecting means provided on a conveying path is later than a scheduled paper sheet feeding timing, it is determined that the winding jam of the paper sheet occurs, then, the image forming operation is interrupted, while the conveyance delay caused by the roller slippage on the conveying path may erroneously determine the winding jam of the paper sheet, consequently, the productivity is reduced. <P>SOLUTION: An image forming device is provided with: the fixing device which includes a pair of rotating bodies rotating in pressure contact with each other and has a heat supply means for supplying the heat to the rotating bodies so as to fix a toner image transferred onto a recording medium; a member in contact with the rotating bodies of the fixing device; and a vibration detecting means which is provided in the contact member and detects the vibration when the recording medium is conveyed. The vibration detected by the vibration detecting means during a normal fixing operation is regarded as a first vibration, and when a second vibration different from the first vibration is detected by the vibration detecting means, the abnormality in the fixing device is detected. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fixing device for a copying machine.

  Conventionally, the detection of paper jamming with respect to the fixing roller in the fixing device is performed when the paper detection timing by the detection means for detecting the presence or absence of paper provided in the conveyance path is delayed from the timing at which the paper should be sent. The image forming operation was interrupted because it was judged that the paper was jammed or jammed.

For example, Patent Document 1 and Patent Document 2 can be cited as conventional examples.
JP-A-6-230624 JP 2002-156868 A

  However, it may be judged that a jam has occurred due to a conveyance delay due to slippage of a roller in the conveyance path, and the productivity may be reduced.

  In the present invention, vibration detection means is provided on the member that contacts the fixing roller of the fixing device, the vibration of the member that contacts the fixing roller is detected, and the winding jam is determined from the change in vibration when the paper is wound around the fixing roller. . When the vibration of the member in contact with the fixing roller is detected as a vibration different from the normal vibration, or when the vibration exceeding the threshold is detected for a predetermined time or more, the control determines that the jam is a sticking jam. Or eliminate false detection of jam judgment and reduce downtime. Here, when vibration exceeding a certain other threshold value cannot be detected, it is possible to detect a problem that the contact member that should be in contact with the fixing roller is not in contact.

  Further, by providing vibration detection means in the thermistor or the like that originally contacts the fixing roller, and detecting the vibration, there is an effect of preventing scratches on the fixing roller caused by providing a new member on the fixing roller.

In order to solve the above problems, the present invention
In claim 1,
A fixing device that includes a pair of rotating members that rotate in pressure contact with each other, and that has heat supply means for supplying heat to the rotating members, and fixes the toner image transferred onto the recording medium; and the rotating member of the fixing device And a vibration detecting means provided on the contact member for detecting vibration when the recording medium is conveyed, and the vibration detected by the vibration detecting means in a normal fixing operation is a first vibration. An image forming apparatus that detects that an abnormality has occurred in the fixing device when a second vibration different from the first vibration is detected.

In claim 2,
2. The image forming apparatus according to claim 1, wherein when the vibration detection unit does not detect vibration during image formation, it detects a problem that a member to be in contact with the rotating body is not in contact.

In claim 3,
2. The apparatus according to claim 1, wherein the vibration detecting unit detects vibration exceeding a threshold value, and detects that an abnormality has occurred in the fixing device when the vibration detection unit continues to detect vibration exceeding the threshold value for a predetermined time or more. The image forming apparatus described.

In claim 4,
The image forming apparatus according to claim 1, wherein the abnormality to be detected is paper winding around the fixing device.

In claim 5,
The image forming apparatus according to claim 1, wherein the vibration detection unit is an acceleration sensor.

In claim 6,
The image forming apparatus according to claim 1, wherein the member that contacts the fixing roller is a thermistor.

  The vibration of the member in contact with the fixing roller is detected by using a vibration detection unit, and a paper jam of the fixing roller is determined.

Example 1
FIG. 1 is an embodiment of a fixing device according to the present invention, FIG. 2 is a graph showing the vibration amount of a member that contacts the fixing roller, FIG. 3 is a functional block diagram of the fixing device, and FIG. It is a flowchart explaining operation | movement of. In the embodiment, a fixing device that performs fixing with a roller will be described. However, even a fixing device such as a belt fixing device can be implemented by providing a vibration detecting unit on the contact member.

  In FIG. 1, reference numeral 100 denotes a fixing device main body, which includes a fixing roller 102. The fixing roller 102 is rotated by being driven by a driving source 108 in FIG. 3, and a pressure roller 103 is pressed against the fixing roller 102. The pressure roller 103 cooperates with the fixing roller 102 to form a recording medium on which a toner image is formed. A nip portion for nipping and conveying is formed. A halogen heater 101 as a heating source is disposed in the core of the fixing roller 102, and the surface temperature of the fixing roller 102 is detected by the thermistor 104 in contact therewith, and the heater 101 is controlled by the control of the CPU 201 in FIG. On / off control is performed to keep the surface temperatures of the fixing roller 102 and the pressure roller 103 constant. A fibrous cleaning mechanism 106 is provided above the fixing roller 102. The cleaning mechanism 106 is fed by the feed roller and is taken up by the take-up roller. At this time, a part of the cleaning member 106 comes into contact with the outer peripheral surface of the fixing roller 102 and is pressed against the fixing roller 102 with a predetermined pressure, thereby cleaning the deposits on the surface of the fixing roller 102. When fixing the toner image on the recording medium, the recording medium on which the unfixed toner image is formed is conveyed along the fixing entrance guide 107 toward the nip portion. When the recording medium passes through the nip portion, heat and pressure are applied to the unfixed toner image on the recording medium, and the toner image is fixed on the recording medium. When passing through the nip portion of the recording medium, an offset phenomenon occurs in which a part of the toner forming the unfixed toner image is transferred to the fixing roller 102, and the offset toner adheres to the outer peripheral surface of the fixing roller 102. Further, paper dust generated from the recording medium adheres to the outer peripheral surface of the fixing roller 102. As the fixing roller 102 rotates, the offset toner and paper dust adhering to the outer peripheral surface of the fixing roller 102 are conveyed toward the cleaning mechanism 106. The offset toner and paper dust are collected by the cleaning mechanism 106.

  When the recording medium passes through the nip portion, a vibration sensor 105 is installed on a member that contacts the fixing roller (in this embodiment, the thermistor 104) to detect vibration during operation of the fixing roller 102 (FIG. 2-1). When a value that exceeds a certain threshold TH is detected (FIG. 2-2), it is determined that the sheet has been wound around the fixing roller (FIG. 2). If a vibration amount exceeding a certain threshold value TH2 cannot be detected, it is determined that a member that should be in contact with the fixing roller is not in contact, and a device malfunction can be detected (FIG. 2-3).

  Next, the above flow will be described based on the flowchart shown in FIG. According to the flow of FIG. 4, the sheet is first conveyed at the start of the copying operation (step 1), and vibration is detected by the vibration detecting means provided on the member that contacts the fixing roller (step 2). If the detected vibration amount is smaller than a certain threshold value TH2, it is determined that the member that should be in contact with the fixing roller is not in contact (step 3), and the copying operation is stopped (step 4). If the detected vibration amount is smaller than the preset threshold value TH and larger than the threshold value TH2, the copying operation is continued (step 5). If the detected vibration amount is larger than the threshold value TH, it is determined that the paper has caught on the fixing roller and jammed (step 6), and then the copying operation is stopped (step 7).

  In this system, instead of the conventional roller and halogen heater, the fixing unit is pressed against the sheet with a flat ceramic heater through the thin film, and fixing can be performed immediately without the warm-up time. For a device such as a fixing method (not shown), if there is a member in contact with the sheet, the contact member can be provided with a vibration detecting means and the vibration of the contact member can be detected. is there.

(Example 2)
In the second embodiment, when the vibration detection unit provided in the member in contact with the fixing roller in the first embodiment continuously detects the vibration amount exceeding the threshold for a predetermined time or more after detecting the vibration amount exceeding the threshold ( In FIG. 5), it is determined that the jammed paper is jammed.

  The above flow will be described with reference to the flowchart shown in FIG. First, a sheet is conveyed at the start of a copy operation (step 1). Vibration is detected by vibration detection means provided on a member that contacts the fixing roller (step 2). If the detected vibration amount is smaller than the preset threshold value TH2, it is determined that the member that should be in contact with the fixing roller is not in contact (step 3), and the copying operation is stopped (step 4). If the detected vibration amount is smaller than the preset threshold value TH and larger than TH2, the copying operation is continued (step 5). If the detected vibration amount exceeds a certain threshold value TH, the time T1 at that time is set as the vibration detection start time StartTime. (Step 6). Then, vibration detection after a predetermined time a set in advance is performed (steps 7 and 8), and if the detected vibration amount is smaller than the threshold value TH, the copying operation is continued (step 9). When the detected vibration amount exceeds the threshold value TH, the time T2 at that time is set as EndTime (step 10). If EndTime-StartTime (step 11) does not exceed a predetermined detection time set in advance, the process returns to step 5 to detect vibration again after a predetermined time a. If EndTime-StartTime exceeds a predetermined time, it is determined that a jam has occurred (step 12), and the subsequent copy operation is stopped (step 13).

  As described above, when a vibration amount exceeds a threshold for a predetermined time or more, it is determined that a jam has occurred, thereby preventing erroneous detection. In this way, by continuing detection for a predetermined time, it can be determined that the vibration amount is generated when the paper enters the fixing device.

(Example 3)
FIG. 7 shows an acceleration sensor used in the third embodiment.

  In the third embodiment, an acceleration sensor 301 that detects acceleration / inclination is used as means for detecting vibration of the fixing roller provided on the member that contacts the fixing roller in the first embodiment. In the acceleration sensor 301, when a force is applied to the sensor itself, the weight 303 moves in the opposite direction. The piezoelectric element 302 detects the acceleration applied to the acceleration sensor 301 by receiving the force and generating an electric charge.

  Similar to the first embodiment and the second embodiment, the acceleration sensor 301 is provided on a member that contacts the fixing roller 102, detects a change in acceleration that occurs when the member that contacts the fixing roller 102 vibrates, and fixes the fixing roller. Judgment to 102 is judged.

  Also, during times other than the copy operation, the inclination of the member contacting the fixing roller 102 provided with the acceleration sensor 301 and the copying machine main body is detected from the inclination detected by the acceleration sensor 301, and an inclination different from a predetermined value is detected. If it does, it can be determined as abnormal.

1 is a configuration diagram of a fixing device in Embodiment 1. FIG. FIG. 3 is a diagram illustrating vibration in the first embodiment. 2 is a functional block diagram of a fixing device in Embodiment 1. FIG. 6 is a flowchart of a detection operation for sheet curling according to the first embodiment. FIG. 6 is a diagram illustrating vibration in the second embodiment. 10 is a flowchart of a detection operation for sheet curling according to the second exemplary embodiment. The acceleration sensor used in Example 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Fixing apparatus 101 Heater 102 Fixing roller 103 Pressure roller 104 Temperature detection element 105 Vibration detection means 106 Roller cleaner 107 Fixing entrance guide 201 CPU
202 RAM
203 ROM
301 Acceleration sensor 302 Piezoelectric element 303 Weight

Claims (6)

  A fixing device that includes a pair of rotating members that rotate in pressure contact with each other, and that has heat supply means for supplying heat to the rotating members, and fixes the toner image transferred onto the recording medium; and the rotating member of the fixing device And a vibration detecting means provided on the contact member for detecting vibration when the recording medium is conveyed, and the vibration detected by the vibration detecting means in a normal fixing operation is a first vibration. An image forming apparatus that detects that an abnormality has occurred in the fixing device when a second vibration different from the first vibration is detected.   2. The image forming apparatus according to claim 1, wherein when the vibration detection unit does not detect vibration during image formation, it detects a problem that a member to be in contact with the rotating body is not in contact.   2. The apparatus according to claim 1, wherein the vibration detecting unit detects vibration exceeding a threshold value, and detects that an abnormality has occurred in the fixing device when the vibration detection unit continues to detect vibration exceeding the threshold value for a predetermined time or more. The image forming apparatus described.   The image forming apparatus according to claim 1, wherein the abnormality to be detected is paper winding around the fixing device.   The image forming apparatus according to claim 1, wherein the vibration detection unit is an acceleration sensor.   The image forming apparatus according to claim 1, wherein the member that contacts the fixing roller is a thermistor.

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