JP2006027856A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To continue job by switching to the other paper feed stage without interrupting the job even if defective paper feeding occurs in a paper feed stage in use. <P>SOLUTION: This image forming device having a plurality of paper feed stages comprises a drive means for driving the paper feed stages, a detection means for detecting the state of the drive means, a means for determining a defective paper feed or a state in which the defective paper feed may occur in the paper feed stages feeding recording medium based on the detected results of the state, and a means for switching the paper feed stage to the other paper feed stage when the determination means determines that the device is in the state of the defective paper feed or in a state in which the defective paper feed may occur. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus having a plurality of paper feed stages.

In the conventional apparatus, the apparatus is stopped as a jam even if a paper feed failure occurs in the paper feed stage. To solve this problem, in the conventional technology, for example, as described in Patent Document 1, when the paper feed failure is detected, the paper feed speed is increased or decreased (retry control) to avoid the stop of the device due to the jam. (Fig. 2).
JP-A-8-169632

  However, in the retry control, the recording medium has to be transported to the registration drive unit within a predetermined time (cannot be repeated many times), and the retry control does not necessarily enable refeeding. For this reason, there is a problem in that when the paper cannot be fed even if the retry control is performed, the apparatus is eventually stopped and the downtime of the apparatus due to poor paper feeding occurs.

  The present invention has been made paying attention to the above points. When a paper feed failure is detected from the state of the drive motor of each paper feed stage, the job is continued by switching the paper feed stage to another paper feed stage. By doing so, it is possible to prevent downtime of the device, and it is possible to detect in advance the state that paper feed is likely to fail.In that case, by switching the paper feed stage from the beginning, the cause of paper feed failure after the job is started Even when a paper feed failure occurs during a job and the recording medium blocks the conveyance path, the drive means is rotated in the reverse direction to retreat the recording medium from the conveyance path. An object of the present invention is to provide an image forming apparatus that can continue a job from one paper feed stage.

  According to the present invention, as one of means for solving the above-described problems, in an image forming apparatus having a plurality of paper feed stages, a drive means for driving each paper feed stage and a state of the drive means are detected. Detection means for determining, a means for determining a paper feed failure or a paper feed-prone state in a paper feed stage that feeds a recording medium based on a state detection result, a paper feed failure or a paper feed-prone state, When the determination is made, the downtime of the apparatus is prevented by switching the paper feed stage to another paper feed stage.

  According to the present invention, when a paper feed failure is detected from the state of the drive motor of each paper feed stage, the downtime of the apparatus is prevented by switching the paper feed stage to another paper feed stage and continuing the job. be able to. In addition, since it is possible to detect in advance a state where paper feeding is likely to occur, the cause of paper feeding failure after the job is started can be avoided by switching the paper feeding stage from the beginning. In addition, even when a paper feed failure occurs during a job and the recording medium blocks the transport path, the recording medium is retracted from the transport path by rotating the drive means in the reverse direction, and from other paper feed stages. It is also possible to continue the job.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to examples.

  FIG. 1 and subsequent drawings illustrate an embodiment of the present invention, and the following description will be made in accordance with specific operations. First, the operation of a typical copying machine will be described with reference to FIG.

  In FIG. 3, 317 is a yellow image forming unit, 318 is a magenta image forming unit, 319 is a cyan image forming unit, 320 is a black image forming unit, and the configuration is the same, so the yellow image forming unit 317 will be described in detail. Description of other image forming units is omitted. In the yellow image forming unit 317, 342 is a photosensitive drum, and a motor is installed behind the photosensitive drum to drive the photosensitive drum 342. A latent image is formed on the surface of the photosensitive drum 342 by light from the optical control unit 210 such as a laser or an LED array. Reference numeral 321 denotes primary band electricity, which charges the surface of the photosensitive drum 342 to a predetermined potential to prepare for latent image formation. A developing unit 322 develops the latent image on the photosensitive drum 342 to form a toner image. The developing device 322 includes a sleeve 345 for applying a developing bias for development. Reference numeral 323 denotes a transfer charger, which discharges from the back surface of the transport rotator 5 (for example, a transfer belt) and transfers the toner image on the photosensitive drum 342 to the recording medium 20 on the transport rotator 5. In this embodiment, since the transfer efficiency is good, the cleaner portion is not arranged, but it is known that there is no problem even if the cleaner portion is attached.

  A procedure for forming an image on the recording medium 20 will be described. The recording media 20 stored in the cassettes 340 and 341 are transported one by one to the registration rollers 336 and 337 by the sheet feeding rollers 338 and 339, and are supplied onto the transport rotating body 5 at the image forming timing by the registration rollers 336 and 337. The The fed recording medium 20 is charged by an adsorption charger 346. Reference numeral 348 denotes a transport rotator driving roller that drives the transport rotator 5 and charges the recording medium 20 in a pair with the adsorption charger 346 to attract the recording medium onto the transport rotator 5. Reference numeral 347 denotes a paper front end sensor that detects the front end of the recording medium 20 on the transport rotating body 5. The detection signal of the paper leading edge sensor is sent from the printer unit 901 to the reader unit 902 and is used as a sub-scanning synchronization signal when a video signal is sent from the reader unit 902 to the printer unit 901. Further, in order to avoid thickness unevenness correction of the transport rotator 5 driven by the transport rotator driving roller 348 or to prevent the recording medium 20 from getting on the joint (in the case of a non-seamless belt or the like) of the transport rotator 5, A sensor 19 for detecting the home position of the body 5 is provided. By using this sensor 19, it is possible to form an image at the same position every time. Needless to say, the arrangement of the detection sensors 19 is not particularly limited. Thereafter, the recording medium 20 is conveyed by the conveying rotator 5, and toner images are formed on the surface in the order of YMCK in the image forming units 317 to 320. The recording medium 20 that has passed through the black image forming unit 320 is separated from the transport rotator 5 after being neutralized by the neutralization charger 349 to facilitate separation from the transport rotator 5. The separated recording medium 20 is discharged onto a discharge tray 335 after the toner image is thermally fixed by the fixing unit 7.

  Next, a first embodiment of the present invention will be described. FIG. 4 shows an image forming apparatus having a plurality of paper feed stages (upper paper feed stage 110, middle paper feed stage 120, and lower paper feed stage 130). Details of the paper feed unit are as shown in FIG. Here, the operation will be described with reference to FIGS. 1 and 6 to 8. When the copy job is started, the paper feed motor 111 is turned on in step 101 (hereinafter, S101) (P1 in FIG. 6). In S102, for example, when a feedback control stepping motor having an encoder signal is used for the paper feed motor 111, it is detected based on the encoder signal whether or not the paper feed motor 111 has reached a predetermined number of revolutions within a predetermined time (FIG. 6P2). ). If the predetermined number of rotations has been reached within the predetermined time, the process proceeds to S103, and paper feeding is started. When the recording medium 20 is sequentially conveyed, it is detected by the paper feeding sensor 112 and the paper feeding sensor 140 (P3 and P4 in FIG. 6). When continuous paper feeding is performed, the processes in and after FIG. 6P5 are repeated. The transported recording medium 20 is transported to the image forming process as described above. In S104, it is monitored whether there is an abnormality in the encoder signal of the paper feeding motor 111 during paper feeding (for example, the predetermined rotational speed exceeds ± 3% of the tolerance). If there is no abnormality, the process proceeds to S105 and the paper feeding motor 111 is stopped. (FIG. 6P9). In S102, if the paper feed motor 111 does not reach the predetermined number of rotations within a predetermined time (circled portion in FIG. 7), it is determined that there is a possibility that a paper feed failure may occur, and the process proceeds to S106 and the paper feed motor 111 is stopped. (FIG. 7P2). In step S108, the paper feed stage is switched. For example, the upper paper feed stage 110 is switched to the middle paper feed stage 120. Thereafter, returning to S101, this time, the paper feed motor 121 is driven (P3 in FIG. 7) and the same control is performed. If it is determined in S104 that the encoder signal of the paper feed motor 111 is out of the range of the predetermined rotational speed while the paper feed motor 111 is rotating (circled portion in FIG. 8P4), it is determined that the paper feed is defective, and the process proceeds to S106. The paper motor 111 is stopped (P5 in FIG. 8). In step S108, the paper feed stage is switched. For example, if the upper paper feed stage 110 is switched to the middle paper feed stage 120, the process returns to S101, and this time the paper feed motor 121 is driven (P6 onward in FIG. 8) and the same control is performed. In this embodiment, it has been described that a paper feed motor is judged to be defective by detecting an abnormal rotation speed (out of a predetermined rotation speed). For example, the standard value of a predetermined rotation speed is less than ± 3%. Precautions where there is a possibility of step-out when the tolerance of the predetermined rotation speed is between ± 3% or more and less than 5%. If the tolerance of the predetermined rotation speed is ± 5% or more, the rotation speed is 3% or more to 5 If it is less than%, it is judged that there is a possibility of paper feed failure. In this case, even if there is no step-out, switching the paper feed stage before starting the job avoids the cause of paper feed failure after the job starts. it can.

  In this embodiment, the feedback control stepping motor (determined based on the rotational speed tolerance range) having an encoder signal in the driving means has been described as an example. Whether using a feedback control stepping motor for detection (determined by drive voltage tolerance range) or a DC brushless motor (determined by FG signal cycle detection, drive current tolerance range, drive voltage tolerance range) It is added that the same effect is obtained.

  In addition, when a paper feed failure is detected in the paper feed tray, after retry control is performed once as in the prior art, if the paper still cannot be fed, it is the same even if the paper feed tray is switched to another paper feed as proposed. It goes without saying that the effect of can be obtained.

[Other embodiments]
A second embodiment of the present invention will be described with reference to FIGS. Since the timing chart basically conforms to FIGS. In FIG. 9, when the copy job is started, the paper feed motor 111 is turned on in S101. In S102, for example, when a feedback control stepping motor having an encoder signal is used for the paper feed motor 111, it is detected based on the encoder signal whether the paper feed motor 111 has reached a predetermined number of revolutions within a predetermined time. If the predetermined number of rotations has been reached within a predetermined time, the process proceeds to S103 to start paper feed, and the paper feed sensor 112 and paper feed sensor 140 detect when the recording medium 20 is sequentially conveyed. The transported recording medium 20 is transported to the image forming process as described above. In S104, it is monitored whether there is an abnormality in the encoder signal of the paper feeding motor 111 during paper feeding (for example, the predetermined rotational speed exceeds ± 3% of the tolerance). If there is no abnormality, the process proceeds to S105 and the paper feeding motor 111 is stopped. . If the paper feed motor 111 does not reach the predetermined rotation speed within a predetermined time in S102, it is determined that there is a possibility of paper feed failure, and the process proceeds to S106 and the paper feed motor 111 is stopped. In step S108, the paper feed stage is switched. For example, the upper paper feed stage 110 is switched to the middle paper feed stage 120. Then, in S109, as shown in FIG. 11, it is determined that there is a possibility that a paper feed failure may occur in the operation unit 10 due to an abnormality (rotational speed abnormality) of the paper feed motor 111, and another switched paper feed. The column 120 displays that the copy job is continued. Thereafter, the process returns to S101 and this time the paper feed motor 121 is driven to perform the same control. If it is determined in S104 that the encoder signal of the paper feed motor 111 is out of the predetermined rotational speed range while the paper feed motor 111 is rotating, it is determined that the paper feed is defective, and the process advances to S106 to stop the paper feed motor 111. In step S108, the paper feed stage is switched. For example, the upper paper feed stage 110 is switched to the middle paper feed stage 120. In step S109, as shown in FIG. 12, the paper feed stage 110 in which a paper feed failure has occurred in the operation unit 10 due to an abnormality in the paper feed motor 111 (rotation speed abnormality), another switched paper feed stage 120, and a copy job. Is displayed. Thereafter, the process returns to S101 and this time the paper feed motor 121 is driven to perform the same control. As shown in FIGS. 13 and 14, when displaying on the operation unit 10 that the paper feed stage has been switched in S 109, a paper feed failure occurs due to an abnormality in the paper feed motor 111 (abnormal rotation speed). Only one of the selected paper feed tray 110 or another switched paper feed tray 120 may be displayed. In this embodiment, it has been described that a paper feed motor is judged to be defective by detecting an abnormal rotation speed (out of a predetermined rotation speed). For example, the standard value of a predetermined rotation speed is less than ± 3%. Precautions where there is a possibility of step-out when the tolerance of the predetermined rotation speed is between ± 3% or more and less than 5%. If the tolerance of the predetermined rotation speed is ± 5% or more, the rotation speed is 3% or more to 5%. If it is less than%, it is judged that there is a possibility of paper feed failure. In this case, even if there is no step-out, switching the paper feed stage before starting the job avoids the cause of paper feed failure after the job starts. it can.

  In this embodiment, the feedback control stepping motor (determined based on the rotational speed tolerance range) having an encoder signal in the driving means has been described as an example. Whether using a feedback control stepping motor for detection (determined by drive voltage tolerance range) or a DC brushless motor (determined by FG signal cycle detection, drive current tolerance range, drive voltage tolerance range) It is added that the same effect is obtained.

  Also, when a paper feed failure in a paper feed stage is detected, after retry control is performed once as in the prior art, even if it still cannot be fed, the same can be done by switching the paper feed stage to another paper feed stage as in this plan It goes without saying that the effect of can be obtained.

[Other Example 2]
A third embodiment of the present invention will be described with reference to FIGS. Since the timing chart basically conforms to FIGS. When a copy job is started in FIG. 15, the paper feed motor 111 is turned on in S101. In S102, for example, when a feedback control stepping motor having an encoder signal is used for the paper feed motor 111, it is detected based on the encoder signal whether the paper feed motor 111 has reached a predetermined number of revolutions within a predetermined time. If the predetermined number of rotations has been reached within a predetermined time, the process proceeds to S103 to start paper feed, and the paper feed sensor 112 and paper feed sensor 140 detect when the recording medium 20 is sequentially conveyed. The transported recording medium 20 is transported to the image forming process as described above. In S104, it is monitored whether there is an abnormality in the encoder signal of the paper feeding motor 111 during paper feeding (for example, the predetermined rotational speed exceeds ± 3% of the tolerance). If there is no abnormality, the process proceeds to S105 and the paper feeding motor 111 is stopped. . In S102, if the paper feed motor 111 does not reach the predetermined rotation speed within a predetermined time, it is determined that there is a possibility of paper feed failure, and the process proceeds to S108 to stop the paper feed motor 111. In step S109, the paper feed stage is switched. For example, the upper paper feed stage 110 is switched to the middle paper feed stage 120. Thereafter, the process returns to S101 and this time the paper feed motor 121 is driven to perform the same control. If it is determined in S104 that the encoder signal of the paper feed motor 111 is out of the predetermined rotational speed range while the paper feed motor 111 is rotating, it is determined that the paper feed is defective, and the process advances to S106 to stop the paper feed motor 111. At this time, it is predicted that the recording medium 20 is stagnant on the conveyance path within a distance corresponding to the time during which the sheet feeding motor 111 has been driven after being picked up (FIG. 16). The recording medium 20 is retreated from the conveyance path as shown in FIG. 17 by rotating in the reverse direction by the same time or the number of pulses as the driving time after the motor 111 was picked up. In step S109, the paper feed stage is switched. For example, the upper paper feed stage 110 is switched to the middle paper feed stage 120. Thereafter, the process returns to S101 and this time the paper feed motor 121 is driven to perform the same control. In this embodiment, it has been described that a paper feed motor is judged to be defective by detecting an abnormal rotation speed (out of a predetermined rotation speed). For example, the standard value of a predetermined rotation speed is less than ± 3%. Precautions where there is a possibility of step-out when the tolerance of the predetermined rotation speed is between ± 3% or more and less than 5%. If the tolerance of the predetermined rotation speed is ± 5% or more, the rotation speed is 3% or more to 5%. If it is less than%, it is judged that there is a possibility of paper feed failure. In this case, even if there is no step-out, switching the paper feed stage before starting the job avoids the cause of paper feed failure after the job starts. it can.

  In this embodiment, the feedback control stepping motor (determined based on the rotational speed tolerance range) having an encoder signal in the driving means has been described as an example. Whether using a feedback control stepping motor for detection (determined by drive voltage tolerance range) or a DC brushless motor (determined by FG signal cycle detection, drive current tolerance range, drive voltage tolerance range) It is added that the same effect is obtained.

  Also, when a paper feed failure in a paper feed stage is detected, after retry control is performed once as in the prior art, even if it still cannot be fed, the same can be done by switching the paper feed stage to another paper feed stage as in this plan It goes without saying that the effect of can be obtained.

The figure showing claim 1 of the present invention Diagram showing conventional control Diagram showing typical device Figure representing an embodiment of the claims of the present invention Figure representing an embodiment of the claims of the present invention The figure showing the Example of Claim 1 of this invention The figure showing the Example of Claim 1 of this invention The figure showing the Example of Claim 1 of this invention The figure showing Claim 4 and Claim 5 of this invention The figure showing Claim 4 and Claim 5 of this invention The figure showing Claim 4 and Claim 5 of this invention The figure showing Claim 4 of the present invention The figure showing Claim 5 of the present invention The figure showing Claim 5 of the present invention The figure showing Claim 6 and Claim 7 of this invention The figure showing Claim 6 and Claim 7 of this invention The figure showing Claim 6 and Claim 7 of this invention

Explanation of symbols

10 operation unit 20 recording medium 110 upper sheet feeding unit 120 middle sheet feeding unit 130 lower sheet feeding unit 111 upper sheet feeding motor 121 middle sheet feeding motor 131 lower sheet feeding motor 112 upper sheet feeding sensor 122 middle sheet feeding sensor 132 lower sheet feeding Sensor 140 Paper feed sensor

Claims (7)

  In an image forming apparatus having a plurality of paper feed stages, a drive unit for driving each paper feed stage, a detection means for detecting the state of the drive means, and a recording medium are fed based on the state detection result Means for determining a paper feed failure in a paper feed stage or a state that is likely to cause a paper feed failure, and switching a paper feed stage to another paper feed stage when it is determined that a paper feed failure or a paper feed failure is likely to occur An image forming apparatus.   2. The image forming apparatus according to claim 1, wherein a feedback control stepping motor is used as the driving unit.   2. The image forming apparatus according to claim 1, wherein a DC brushless motor is used as the driving unit.   The image forming apparatus according to claim 1, further comprising a display unit that displays a paper feed stage determined to be a paper feed failure, another switched paper feed stage, and a job being continued.   And a display unit configured to display that the job is continued and one of the paper feed stages determined to be defective or the other paper feed stage switched. Item 2. The image forming apparatus according to Item 1.   2. The image forming apparatus according to claim 1, wherein when a paper feed failure is detected, the drive unit is rotated in the reverse direction to retract the recording medium from the conveyance path, and then the paper feed is switched to another paper feed stage.   7. The image forming apparatus according to claim 6, wherein when the driving unit is reversely rotated, the driving unit is rotated in the reverse direction by the time or driving pulse for which the driving unit has been driven.

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