JP2005173041A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus, capable of preventing danger such as a fire by making a user recognize possibility that transfer paper remains in a fixing unit, without incurring cost, using a simple constitution. <P>SOLUTION: The image forming apparatus has a fixing device, equipped with a pair of rollers heated by a heating means and an outside cover opened/closed when transfer paper is jammed in a pair of rollers and fixing an unfixed image transported on the transfer paper, by holding and transporting the transfer paper to which the image has been transferred by a pair of rollers, and has a transfer paper detecting means, provided on at least either of a pair of rollers and detecting the transfer paper; an opening/closing detection means for detecting the opening/closing of a front cover and a rear cover with which a pair of rollers is covered; a non-volatile jamming occurrence recording means for recording the occurrence of fixing jam caused by laying the transfer paper on a pair of rollers; a non-volatile cover opening/closing recording means for recording the opening/closing of the outside cover, when the fixing jam occurs; an energizing control means for controlling the energizing of the heating means; and an operation control means for controlling the operation of the energizing control means, based on the result of detection by the detection means. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus, and more particularly, includes a roller pair heated by a heating unit, and fixes and transfers an unfixed image carried on the transfer paper by sandwiching and transferring the transfer paper after transfer by the roller pair. The present invention relates to an image forming apparatus having a fixing device.

  2. Description of the Related Art Conventionally, image forming apparatuses such as copiers, printers, facsimiles, and the like have widely adopted fixing devices that include a roller pair including a fixing roller and a pressure roller, for example. In such an image forming apparatus, when a transfer paper carrying an unfixed toner image is nipped and conveyed between a fixing roller and a pressure roller, the unfixed toner image is fixed on the transfer paper by the action of heat and pressure. In this fixing operation, the toner image is melted and attached to the fixing roller, and thereby, a jam (for example, fixing jam) such as transfer paper sticking and winding around the fixing roller can occur.

  Various proposals have been made to reduce the occurrence of such problems, but it is difficult to completely prevent jamming in the fixing unit such as winding of transfer paper. Transfer paper detecting means for detecting the occurrence of paper jam is provided. As such a conventional fixing roller jam detection means, jam detection is performed at the ON / OFF timing of a paper discharge sensor provided downstream of the fixing roller.

  The first jam release method is to open / close the front cover or the rear cover, and when the transfer paper detection means detects the jam release, the second is the state in which the transfer paper detection means detects the jam release. When the main power was turned on / off.

As a prior art example, a detection unit for detecting a transfer material provided on at least one of the fixing rollers, a control unit for controlling energization to the halogen lamp, and an operation of the energization control unit based on the detection result of the detection unit There is an “image forming apparatus” that can reliably detect a transfer material wound around a fixing roller (see, for example, Patent Document 1).
JP 2001-117413 A

  However, in the conventional image forming apparatus as disclosed in Patent Document 1, the jam removal method does not check the front and back of the fixing roller. Therefore, when the transfer paper that has been cut off during the jam processing is forgotten to be removed, When the main power is turned ON / OFF with the detection means detecting that there is no paper that is the cause of the jam, the transfer paper remains on the fixing roller. There was a problem that there was a danger of smoking.

  Therefore, it is necessary to prevent dangers such as fire and smoke from being used by the user without noticing if there is a cut that cannot be detected by the image forming apparatus either before or after the fixing unit.

  Also, if a fixing jam occurs when there is transfer paper in a location that the device cannot detect, and the user turns off the main power without performing jam processing, the next user to use has transfer paper in the device. It is necessary to prevent danger such as fire and smoke by using it without noticing.

  The present invention has been made in view of the above circumstances, and has an image formation that prevents the risk of fire and the like by allowing the user to recognize the possibility of transfer paper remaining in the fixing unit with a simple configuration and without cost. An object is to provide an apparatus.

  In order to achieve this object, the invention described in claim 1 comprises a roller pair heated by the heating means, and an exterior cover that opens and closes when the transfer paper is jammed in the roller pair. In an image forming apparatus having a fixing device that fixes an unfixed image carried on a transfer paper by sandwiching and transporting the transfer paper, the transfer paper detecting means is provided on at least one of the roller pair and detects the transfer paper An open / close detecting means for detecting opening / closing of the front cover and the rear cover covering the roller pair, a non-volatile jam occurrence recording means for recording occurrence of a fixing jam caused by the transfer paper being applied to the roller pair, and a fixing Based on the detection result of the non-volatile cover opening / closing recording means for recording the opening / closing of the exterior cover, the energization control means for controlling the energization to the heating means, and the detection means when a jam occurs And having a an operation control means for controlling the operation of the electric control means.

  According to a second aspect of the present invention, in the first aspect of the invention, when a fixing jam occurs, the open / close detection means detects the opening / closing of both the front cover and the rear cover, and the transfer paper detection means detects the cause of the jam. It is determined that the fixing jam has been released only by detecting that the transfer paper is removed, and the fixing heating is not performed until then.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the fixing jam is not released even if the main power is turned ON / OFF when the fixing jam occurs.

  According to the present invention, when a fixing jam occurs, the user can copy by not releasing the jam even if the main power is turned on / off until an opening / closing of the front and rear covers is detected without adding an additional sensor or the like. It is necessary to open and close the cover in order to start printing, and it is necessary to check if the transfer paper has been forgotten to be removed during jam processing. The risk of fire or smoke from the transfer paper due to heating can be prevented.

  The best mode for carrying out the present invention will be described below in detail with reference to the accompanying drawings.

First, an image forming apparatus according to an embodiment of the present invention will be described with reference to FIG.
A belt-like photoreceptor 1 as an image carrier is rotatably supported by rotating rollers 2 and 3 and is rotated in the direction of an arrow by a driving device (not shown). A charging device 4, a charge eliminating lamp (not shown), and a cleaning device (not shown) are disposed on the outer periphery of the photoreceptor 1. A revolver type multi-color developing device 6 including yellow, magenta, and cyan developing units and a black developing unit containing black toner is disposed downstream of the optical writing unit.

  The upper portion of the photoreceptor 1 is in contact with the intermediate transfer belt 10, and the intermediate transfer belt 10 is rotatably supported by rotating rollers 11 and 12. The toner image on the photoreceptor 1 is transferred to the surface of the intermediate transfer belt by a biasing unit (not shown) on the back side of the intermediate transfer belt 10. The photoreceptor 1 is cleaned for each color, and a toner image of a predetermined color is sequentially formed on the photoreceptor 1 and transferred to the same position on the intermediate transfer belt every time the intermediate transfer belt is rotated. For example, a full color toner image in which yellow, magenta, cyan, and black images are superimposed is formed on the transfer belt. The color toner image on the intermediate transfer belt 10 is transferred from the paper feeding unit (not shown) to the nip between the intermediate transfer belt 10 and the transfer roller 14 via the transport roller 8 and the registration roller 9, and the position of the sheet and the image is normal. The timing is taken to be conveyed. The transfer material on which the toner images of a plurality of colors on the intermediate transfer belt 10 are collectively delivered by the action of the transfer roller 14 is sent to the fixing device 30, and after the toner image on the paper is fixed, the transfer material is taken out of the apparatus. Discharged. 1 is a cooling fan, 16 is an engine control unit, 17 is a controller, and 18 is an external temperature sensor.

  Next, the configuration of the fixing device of the image forming apparatus which is an embodiment of the present invention will be described. As shown in FIG. 4, the fixing device of the present embodiment is a front cover that is a roller pair 34 heated by a heating unit, and an exterior cover that is opened and closed by a user when transfer paper is jammed in the roller pair 34. 32 and a rear cover 33, and the untransferred image carried on the transfer paper is fixed by sandwiching and transferring the transfer paper after transfer by the roller pair 34.

  Further, as shown in FIG. 1, the control system of the image forming apparatus according to the present embodiment includes a transfer sheet detecting unit 35 that detects a transfer sheet provided on at least one of the roller pair, and a front cover 32 that covers the roller pair 34. And an open / close detection means 36 for detecting the opening / closing of the rear cover 33, a non-volatile jam generation recording means 37 for recording the occurrence of a fixing jam caused by the transfer paper being applied to the roller pair 34, and an exterior when the fixing jam occurs. Non-volatile cover opening / closing recording means 38 for recording opening / closing of the cover, energization control means 39 for controlling energization to the heating means, and operation control means 40 for controlling the operation of the energization control means based on the detection result of the detection means, And CPU 41 for controlling each of the above means. In this embodiment, the NV-RAM is used as the jam occurrence recording means 37 and the cover open / close recording means 38 as described below, but the present invention is not limited to this, and any nonvolatile memory can be applied. It is.

  As shown in FIG. 4, when a detection signal of a transfer material such as transfer paper is transmitted from a sensor (not shown) by the transfer paper detection means 35 provided in the vicinity of the roller pair 34, the signal is converted into an A / D converter ( (Not shown) and sent to the CPU 41. The CPU 41 applies a D / A converter (not shown) to the operation control means 40 for controlling the operation of the energization control means 39 for heating the fixing roller pair 34 when the transfer paper detection means 35 detects the transfer material. Thus, control is performed so that both of the fixing roller pair 34 are not heated, that is, energization is stopped. At this time, the motor (driving means) (not shown) that drives the fixing roller pair 34 is controlled not to operate.

  When a fixing jam occurs in the image forming apparatus of the present invention as described above, the opening / closing detection means 36 detects the opening / closing of both the front cover 32 and the rear cover 33, and the transfer paper detection means 35 causes the jam. The CPU 41 determines that the fixing jam has been released for the first time by detecting that a certain transfer sheet has been removed, and controls the copying operation by the operation control means 40 so as not to perform fixing heating until then. Further, in accordance with a command from the CPU 41, the operation control means 40 performs control not to release the fixing jam even if the user turns on / off the main power supply when the fixing jam occurs.

  Next, control processing of the image forming apparatus of the present invention will be described with reference to each flowchart.

  As shown in FIG. 2, when a fixing jam occurs in a state where the transfer paper is placed in the fixing unit (fixing device) (S11 / YES), the fact that the fixing jam has occurred is NV- The data is stored in the RAM, and the user is notified of the occurrence of a jam (S12). Then, when the user opens and closes the front cover 32 shown in FIG. 4 to perform jam processing (S13 / YES), the opening / closing record of the front cover 32 is stored in the NV-RAM as the cover opening / closing recording means (S14). . Similarly, when the user opens / closes the rear cover 33 shown in FIG. 4 to perform jam processing (S15 / YES), the opening / closing record of the rear cover 33 is stored in the NV-RAM as the cover opening / closing recording means (S16). ). Then, the opening / closing records of both the front and rear covers are stored together (S17 / YES), and when the front and rear covers are closed, the transfer paper detection means detects that there is no paper causing the jam (S18). / YES), the fixing jam stored in the NV-RAM as the jam occurrence recording means is canceled (S19).

  Therefore, in the image forming apparatus according to the embodiment of the present invention, even if the transfer paper in the fixing device is removed by the user and the transfer paper detection unit detects that there is no residual paper, the transfer paper is cut off on the opposite side. There is a possibility that etc. remain, so do not release the jam. Then, when the front and rear covers are opened and closed, and the transfer paper detection means detects the absence of paper, jamming is canceled for the first time.

  As shown in FIG. 3, a process when the main power of the image forming apparatus is turned on / off when a fixing jam occurs will be described. When the main power supply of the image forming apparatus is turned on, the fixing jam log recorded in the NV-RAM serving as the jam occurrence recording means is checked, and the fixing jam occurrence record is present in the NV-RAM (S21 / YES). Then, the user is notified again that there is a fixing jam (S22). Thereafter, the processing is the same as that in the first embodiment (S23 to S29).

  Therefore, according to the embodiment of the present invention, when a fixing jam occurs, the jam is not released even if the main power is turned ON / OFF until an opening / closing of the front and rear covers is detected without adding an additional sensor or the like. Therefore, the user must always open and close the cover to start copying, and inevitably check for forgetting to remove the transfer paper that was cut off at the time of jam processing, so that the transfer paper remains on the fixing roller. Thus, it is possible to prevent the risk of fire or smoke from the transfer paper due to reheating of the fixing roller.

  As mentioned above, although the Example of this invention was described, it is not limited to the said Example, A various deformation | transformation is possible in the range which does not deviate from the summary.

It is a control block diagram which concerns on the Example of this invention. It is a flowchart which shows the process of Example 1 of this invention. It is a flowchart which shows the process of Example 2 of this invention. FIG. 2 is a schematic layout diagram illustrating a side surface of a fixing device according to an embodiment of the present invention. 1 is a schematic arrangement diagram illustrating a side surface of an image forming apparatus according to an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 2, 3, 11, 12 Rotating roller 4 Charging device 5 Laser writing unit 6 Multicolor developing device 8 Conveyance roller 9 Registration roller 10 Intermediate transfer belt 14 Transfer roller 15 Cooling fan 16 Engine control unit 17 Controller 18 External temperature sensor DESCRIPTION OF SYMBOLS 30 Fixing device 31 Image forming apparatus 32 Front cover 33 Rear cover 34 Roller pair 35 Transfer paper detection means 36 Opening / closing detection means 37 Jam generation recording means 38 Cover open / close recording means 39 Energization control means 40 Operation control means 41 CPU

Claims (3)

A pair of rollers heated by a heating means;
An exterior cover that opens and closes when the transfer paper is jammed in the roller pair,
In the image forming apparatus having a fixing device that fixes the unfixed image carried on the transfer paper by sandwiching and transferring the transfer paper after the transfer by the roller pair,
A transfer paper detecting means provided on at least one of the roller pair for detecting the transfer paper;
Open / close detecting means for detecting opening / closing of a front cover and a rear cover covering the roller pair;
Non-volatile jam occurrence recording means for recording the occurrence of a fixing jam caused by the transfer paper being applied to the roller pair;
A non-volatile cover opening / closing recording means for recording opening / closing of the outer cover when the fixing jam occurs;
Energization control means for controlling energization to the heating means;
Operation control means for controlling the operation of the energization control means based on the detection result of the detection means;
An image forming apparatus comprising:   When the fixing jam occurs, the open / close detection means detects opening / closing of both the front cover and the rear cover, and the transfer paper detection means detects that the transfer paper causing the jam has been removed. 2. The image forming apparatus according to claim 1, wherein it is determined that the fixing jam is released for the first time, and fixing heating is not performed until that time.   3. The image forming apparatus according to claim 1, wherein the fixing jam is not released even if a main power is turned on / off when the fixing jam occurs. 4.

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