JP2007045609A - Paper carrying device and paper carrying electromagnetic clutch control method to be used for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper carrying device having simple and inexpensive construction for reducing connection noises while securing the partial engagement condition of an electromagnetic clutch without impairing carrying performance independently of the dispersion of the load property of the electromagnetic clutch or a drive transmission system, and to provide a paper carrying electromagnetic clutch control method to be used for the same. <P>SOLUTION: The paper carrying device comprises a pair of carrying rolls 58, 59 between which recording paper is held to be carried, a drive shaft 58<SB>0</SB>, the electromagnetic clutch C for connecting the drive shaft 58<SB>0</SB>to a driving source M via a drive transmission mechanism, an arrival time detecting means for detecting an arrival time for the recording paper from the pair of carrying rolls 58, 59 to a predetermined carriage point, and a voltage regulating means CR for controlling voltage to be applied to the electromagnetic clutch C. The voltage regulating means CR applies to the electromagnetic clutch C stepwise voltage which increases in sequence until reaching a steady value and controls the stepwise voltage to be changed in accordance with a result detected by the arrival time detecting means. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sheet conveying apparatus for an image forming apparatus that controls driving of a conveying roll by an electromagnetic clutch, and a control method therefor, and more particularly to a sheet conveying apparatus that reduces the connection noise of an electromagnetic clutch and a sheet conveying used in the sheet conveying apparatus. The present invention relates to an electromagnetic clutch control method.

JP-A-4-288559 JP-A-5-265102

  Conventionally, in an image forming apparatus, various drive parts are arranged. As one measure for transmitting power by connecting such drive parts, a drive source, and a drive transmission mechanism by electromagnetic force, an electromagnetic clutch is used. It is used. And when connecting such an electromagnetic clutch, it was normal to apply a predetermined voltage (for example, 24V) at a stretch.

  By the way, when a predetermined voltage is applied to the electromagnetic clutch all at once in this way, the connection sound at the time of coupling the electromagnetic clutch is increased, and there is a case where the noise standard is not satisfied.

  Therefore, when the electromagnetic clutch is connected, an attempt is made to reduce the noise by gradually increasing the applied voltage to connect the electromagnetic clutch in a semi-connected state, that is, a so-called half-clutch state (for example, Patent Document 1). , 2).

  Here, in Patent Document 1, an electrostatic latent image carrier and a flywheel are configured to be contactable and separable by an electromagnetic clutch, and a voltage that increases stepwise is applied to the electromagnetic clutch, so that an abrupt load on the drive system is applied. An image forming apparatus that suppresses fluctuations is disclosed.

  Further, Patent Document 2 uses an electromagnetic clutch capable of forward and reverse rotation for a scanning system that scans an original, and applies a voltage that rises stepwise to the electromagnetic clutch so that the electromagnetic clutch is in a semi-connected state. A scanning system driving device for an image forming apparatus that reduces noise is disclosed.

  However, the prior art disclosed in the above patent document has the following problems.

  That is, in the above-described prior art, the stepped voltage applied to the electromagnetic clutch is sufficiently long in the time and the number of steps (number of steps) until reaching the predetermined voltage, and the number of steps can be sufficiently large. However, although the effect of reducing noise is high, the delay in the connection of the electromagnetic clutch affects the productivity in practice, so that it cannot spend much time until the connection is completed. Therefore, if the coupling of the electromagnetic clutch is completed in a short time, the electromagnetic clutch is semi-coupled due to the distance between the clutch plates of the electromagnetic clutch, the variation in the attractive force, the variation in the load characteristics of the drive transmission system, etc. It is difficult to adjust the optimum applied voltage, and as a result, a semi-connected state cannot be realized, and there is a problem that noise during connection cannot be reduced.

  Therefore, the present invention has been made in view of the above-described problems of the prior art, and the electromagnetic clutch is semi-coupled without impairing the transport performance regardless of variations in load characteristics of the electromagnetic clutch and the drive transmission system. It is an object of the present invention to provide a sheet conveying apparatus that secures a state and realizes a low connection sound and a method for controlling a sheet conveying electromagnetic clutch used therefor with a simple configuration at low cost.

  In order to achieve the above object, a sheet conveying apparatus of the present invention includes a pair of conveying rolls that face each other and convey a recording sheet between them, a drive shaft that drives one of the pair of conveying rolls, and a predetermined voltage. Is applied to the drive shaft and a drive source for driving the drive shaft via a drive transmission mechanism, and is provided on the downstream side of the transport roll pair in the transport path of the recording paper. An arrival time detecting means for detecting the arrival time of the recording paper from the pair of conveying rolls to a predetermined conveying point; and a voltage adjusting means for controlling a voltage applied to the electromagnetic clutch, the voltage adjusting means, A stepped voltage that sequentially increases until reaching a steady value is applied to the electromagnetic clutch, and the stepped voltage is changed and controlled based on a detection result of the arrival time detecting means. Is shall.

  In the sheet conveying apparatus of the present invention configured as described above, the voltage adjusting means applies a stepped voltage that sequentially increases until reaching a steady value to the electromagnetic clutch, thereby ensuring a semi-connected state of the electromagnetic clutch. At the same time, by changing and controlling the stepped voltage based on the detection result of the arrival time detection means, the connection sound is reduced without impairing the transport performance (productivity) regardless of the variation in the load characteristics of the electromagnetic clutch or drive transmission system. It is possible to provide a paper conveyance device that achieves noise reduction with a simple configuration at low cost.

  Here, the voltage adjusting means reduces the stepped voltage applied to the electromagnetic clutch when the arrival time is shorter than a predetermined specified time, and the electromagnetic clutch when the arrival time is longer than the predetermined specified time. The stepped voltage applied to may be increased.

  When configured in this way, the voltage adjusting means reduces the stepped voltage applied to the electromagnetic clutch when the arrival time is shorter than the predetermined specified time, and when the arrival time is longer than the predetermined specified time. Since the stepped voltage applied to the electromagnetic clutch is increased, the feedback control of the electromagnetic clutch according to the variation in the characteristics of the individual element members relating to the sheet conveyance can be realized more easily.

  Further, the voltage adjusting means stores the stepped voltage value at which the specified time is reached at the time when the paper arrival time converges to a predetermined specified time in the storage means. A voltage may be applied to the electromagnetic clutch based on the stored voltage value.

  In general, the characteristics of element members such as an electromagnetic clutch and a drive transmission system do not change during a predetermined period.

  Therefore, in such a configuration, when the paper arrival time converges to a predetermined specified time, the voltage adjusting means stores the stepped voltage value that has achieved the specified time in the storage means, and the subsequent paper When transporting, voltage is applied to the electromagnetic clutch based on the stored voltage value, so transport control according to the characteristics of the individual element members without changing the applied voltage each time recording paper is transported Can be realized even more easily.

  Further, the voltage adjusting means may perform change control of the stepped applied voltage based on a detection result of the arrival time detecting means every elapse of a predetermined period.

  When configured in this way, the characteristics of the component members change over time. For example, the voltage adjustment means performs a staircase based on the detection result of the arrival time detection means for each predetermined period according to the number of prints. By carrying out the change control of the state applied voltage, it is possible to more effectively realize the transport control according to the change in characteristics of the element member over time.

  The method for controlling the electromagnetic clutch for conveying a sheet according to the present invention includes a pair of conveying rolls that are opposed to each other and convey a recording sheet therebetween, a drive shaft that drives one of the pair of conveying rolls, and a steady value. By applying a stepped voltage that gradually increases until it reaches, an electromagnetic clutch that connects the drive shaft and a drive source that drives the drive shaft through a drive transmission mechanism, In this state, the voltage application to the electromagnetic clutch is temporarily stopped, and then the voltage is applied to the electromagnetic clutch to convey the recording paper, and the recording paper from the conveyance roll to the predetermined conveyance point is conveyed. The arrival time is measured, and the voltage applied to the electromagnetic clutch is changed and controlled based on the measurement result.

  According to the control method of the electromagnetic clutch for paper conveyance of the present invention configured as described above, voltage application to the electromagnetic clutch is temporarily stopped in a state where the recording paper is nipped between the pair of conveyance rollers, and then the electromagnetic clutch Since the recording paper is conveyed by applying a voltage to it, the arrival time of the recording paper from the conveyance roll to a predetermined conveyance point is measured, and the voltage applied to the electromagnetic clutch is changed and controlled based on this measurement result. Regardless of variations in load characteristics of the drive transmission system and the drive transmission system, a method for controlling the electromagnetic clutch for paper conveyance that ensures a semi-coupled state of the electromagnetic clutch without impairing the conveyance performance (productivity) and realizes low connection noise Can be realized easily.

  According to the present invention, there is provided a paper transport device that ensures a semi-coupled state of the electromagnetic clutch without impairing the transport performance regardless of variations in load characteristics of the electromagnetic clutch or the drive transmission system, and realizes a low connection sound. The control method of the electromagnetic clutch for paper conveyance used for this can be realized at a low cost with a simple configuration.

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

  First, a schematic configuration of an image forming apparatus according to an embodiment of the present invention will be described with reference to FIG.

  As shown in FIG. 1, an image forming apparatus 100 includes an image forming apparatus main body 101, an automatic document feeder 102 provided so as to open and close an upper surface of the main body 101, and the automatic document feeder 102. An image reading unit 103 that reads an image of a fed document and converts it into an image signal, an image forming unit 104 that forms a toner image on a recording sheet based on the image signal from the image reading unit 103, and the image formation The paper supply unit 105 supplies recording paper to the unit 104. The paper feed unit 105 incorporates a paper transport device according to the present invention based on a paper tray to be described later.

  The image forming unit 104 includes a drum-shaped photoconductor 107, a developing roll 108, an exposure device 109, a transfer roll 110, a fixing device 111, and the like. In this embodiment, the drum-shaped photoconductor 107 and the developing roll 108 are unitized as a xerography unit 106. Further, in the present embodiment, the normal paper tray 5 is disposed in the image forming unit 104, and one side (in this example, the right side in the drawing) is returned for double-sided printing. A conveyance path 12R is formed.

  The paper feed unit 105 has paper trays 2, 3, and 4 arranged in a number of stages, and a plurality of pairs of conveyance rolls 58 and 59 are provided on one side surface (in this example, the right side surface in the figure). An arranged paper conveyance path 12 is formed. A pickup roll 51, a feed roll 53, a retard roll 55, and the like constituting a paper feeding unit for drawing out the recording paper are disposed on the feeding sides of the paper trays 2 to 4, respectively.

  In addition, a cover member 60 configured to be openable and closable in the horizontal direction is disposed on one side surface (right side surface in this example) of the paper feeding unit 105. It is formed so that it can move integrally. Thus, by opening the cover member 60, the paper jam in the paper transport path 12 can be easily removed. The drive control and conveyance control of these components are controlled by a device controller CR provided in the image forming unit.

  In the image forming apparatus 100 configured as described above, the image information of the document set on the automatic document feeder is read by the image reading unit 103, and based on this image information, the photosensitive drum 107 is not shown. After being charged to a predetermined potential by the charging device, exposure based on predetermined image information is performed by, for example, laser light from the exposure device 109, and an electrostatic latent image is formed on the photosensitive drum 107. The electrostatic latent image on the photosensitive drum 107 is converted into a toner image by the developing roll 108, and the visualized toner image is transferred to the transfer roll 110 disposed to face the photosensitive drum 107. 2, the paper is transferred onto the recording paper sent from the paper trays 2 to 5 toward the transfer roll 110 through the paper conveyance path 12. Thereafter, the transferred recording sheet is sent to the fixing device 111 and subjected to heat and pressure processing, and the toner image is fixed on the recording sheet. The recording sheet after image fixing is discharged to a discharge tray 113 by a discharge roll 112 or is transported to a return transport path 12R and subjected to processing such as duplex printing. The toner remaining on the photosensitive drum 107 is cleaned by a cleaning device (not shown) for the next image formation.

  On the other hand, the recording sheet is conveyed toward the transfer roll 110 from the predetermined sheet tray via the sheet conveyance path 12 with the conveyance direction and timing adjusted.

  For example, the recording sheets stored in the sheet tray 3 are sent out one by one by the pickup roll 51 at a predetermined timing. The fed recording sheet is held by the paired feed roll 53 and retard roll 55 and guided to the sheet conveyance path 12. Here, the retard roll 55 functions to prevent two or more sheets of recording paper from being double-fed.

  The recording paper fed one by one by the roll pairs 53 and 55 is converted from a horizontal posture to a vertical posture by a guide plate (not shown) and guided into the paper conveyance path 12, and then the recording paper is conveyed. It is gripped by the roll pairs 58 and 59 and is conveyed as it is in the vertical sheet conveying path 12. In the present embodiment, the transport roll 58 is driven by a driving means such as a motor via an electromagnetic clutch (not shown), and the transport roll 59 on the side of the cover member 60 facing is driven by the rotation of the drive transport roll 58. The driven roll acts as a pinch roll that presses the recording paper between the rolls.

  These transport rolls are also provided in the return transport path 12R in the same manner, and the recording paper image-formed on one side after exiting the fixing device 111 is switched by a switching member (not shown) in the case of double-sided printing or the like. The transport direction is switched and transported to the return transport path 12R.

  Next, the paper conveying apparatus 50 according to the present invention will be further described with reference to FIG. The paper transport device according to the present invention can be applied to any of the paper transport paths 12 and 12R described above, but is used for the paper transport path 12 provided in the paper feed unit 105 for the sake of simplicity. The paper transport device will be described. FIG. 2 is a perspective view illustrating a schematic configuration of the sheet transport device 50 in a state where the cover member 60 is removed, that is, in a state where the transport roll 59 is removed.

  As shown in FIG. 2, the paper transport device 50 according to the present embodiment includes a pickup roll 51, a feed roll 53, a retard roll 55, and these rolls 51 provided on the delivery side of the paper trays 2 to 4. , 53 and 55, a sheet transport path 12 for transporting the recording sheet fed in the vertical direction is provided.

In the paper transport path 12, transport roll pairs 58a to 58c and 59a to 59c corresponding to the paper trays 2 to 4 are provided. The transport roll 58a~58c is formed so as to respectively rotate integrally with the drive shaft 58a ₀ ~58c _0, in this example, respectively disposed two by two in the central portion of the drive shaft 58a ₀ ~58c ₀ Has been. In the drawing, the driven transport rollers 59a to 59c formed integrally with the cover member 60 that forms one side surface of the paper transport path 12 are omitted.

  Further, a sheet sensor (not shown) for detecting a recording sheet is provided at a predetermined point on the downstream side conveyance path of each of the conveyance roll pairs 58a to 58c and 59a to 59c. As this paper sensor, for example, a conventionally known optical paper sensor can be used.

  In the present embodiment, the time until the recording sheet conveyed by the conveyance rolls 58a to 58c driven at a predetermined timing is detected by a sheet sensor provided at a predetermined point in the conveyance path is, for example, The arrival time detecting means is configured by detecting and measuring with the device controller CR. Further, as the voltage adjusting means, the device controller CR may be diverted, or of course, a voltage adjusting controller may be separately provided.

The drive conveyance roll 58a is disposed on the downstream side of the paper tray 2 provided on the image forming unit 104 side, and a motor M as a drive source and a plurality of transmission gears G ₁₁ and G ₁₁ are provided by an electromagnetic clutch C1. _It is connected to a drive transmission mechanism (not shown) including ₁₂ etc. and is driven. That is, the driving transport rolls 58a, by the connection by applying a voltage to the electromagnetic clutch C1 state (ON state), the driving force through a drive transmission mechanism is transmitted, together with the drive shaft 58a _0, in a predetermined direction It is designed to rotate.

On the other hand, the drive conveyance rolls 58b and 58c are respectively arranged on the downstream side of the paper trays 3 and 4, and include a motor M as a drive source and a plurality of transmission gears G ₂₁ and G ₂₂ by an electromagnetic clutch C2. It is connected to a drive transmission mechanism (not shown) and driven. That is, the driving and conveying rolls 58b and 58c are applied with a voltage to the electromagnetic clutch C2 to be in a connected state (ON state), whereby a driving force is transmitted through the driving transmission mechanism, together with the driving shafts 58b ₀ and 58c _0. , And is rotationally driven in a predetermined direction.

  By the way, the recording paper conveyed into the image forming unit 104 needs to adjust the conveyance timing to the opposite part between the transfer roll 110 and the photosensitive drum 107 constituting the transfer unit. The drive timing, the conveyance speed, and the like of the conveyance roll pair and the conveyance roll pair 58 and 59 in the paper conveyance apparatus are different.

  For this reason, in a state in which the recording paper is nipped between the pair of transport rolls in the image forming unit 104, it is necessary to stop driving of the drive transport rolls 58a disposed in proximity to the image forming unit 104.

  On the other hand, with respect to the drive transport rolls 58b and 58c disposed on the upstream side of the drive transport roll 58a, it is necessary to transport the subsequent recording paper. In other words, in a state where the drive transport roll 58a is stopped, the upstream drive transport rolls 58b and 58c may be driven.

  Therefore, as described above, the drive conveyance roll 58a on the image forming unit 104 side and the drive conveyance rolls 58b and 58c disposed on the upstream side thereof are driven and controlled by separate electromagnetic clutches C1 and C2, respectively. Regardless of the difference in the drive timing of these drive rolls, it is possible to realize the optimum conveyance performance of the recording paper.

  Next, a control method by the voltage adjusting means according to the present invention will be described with reference to FIGS. Note that the object to be controlled by the voltage adjusting unit according to the present invention can be applied to any of the above-described drive conveyance rolls 58a to 58c in the same procedure, but for simplicity, conveyance close to the image forming unit 104 is performed. The procedure of the conveyance control with respect to the roll 58a is demonstrated below.

  First, for example, a recording sheet instructed by an operator and fed from a predetermined sheet tray is once applied with a voltage to the electromagnetic clutch C1 by the controller CR in a state where the recording sheet is nipped by the pair of transport rollers 58a and 59a. Stopped (the electromagnetic clutch is turned off).

  Thereafter, a stepped step voltage that sequentially increases to a steady value as shown in FIG. 4 is applied to the electromagnetic clutch C1. Here, the number of steps of the stepped step voltage can be arbitrarily set.

  As a result, the electromagnetic clutch C1 gradually shifts from the half-clutch state to the connected state, rotationally drives the drive roll 58a, and the recording paper is conveyed from the paper conveyance path 12 into the image forming unit 104 and in the conveyance path. The arrival of the recording sheet is detected by the sheet sensor S provided at a predetermined point, and this information is fed back to the controller CR to calculate the arrival time.

  If the arrival time is shorter than a predetermined specified time, the step-like applied voltage applied to the electromagnetic clutch C1 is reduced, and if longer than the predetermined specified time, the step-like printing voltage is increased. Thus, the controller CR is controlled to change.

  The control steps as described above are repeated until the arrival time of the recording sheet sent from the pair of conveyance rolls 58a and 59a at a predetermined timing reaches a predetermined specified value.

  As a result, an intermediate drive transmission mechanism is interposed between the drive source M and the drive roll 58a, and even if there are variations in characteristics due to electromagnetic clutches or individual differences between these drive transmission mechanisms, With the characteristic variation as a black box, regardless of these characteristic variations, it is possible to maintain the predetermined conveyance performance of the recording paper and perform power transmission by the electromagnetic clutch C1 without impairing the productivity. The electromagnetic clutch C1 can be connected while securing a semi-connected state, and it is possible to realize a reduction in connection sound during connection by simple control.

  The above control procedure exemplifies the case where the drive control of the drive transport roll 58a is performed by the electromagnetic clutch C1, but naturally the drive transport rolls 58b and 58c are controlled by the electromagnetic clutch C2 in the same procedure. May be.

  Further, when the paper arrival time converges to a predetermined specified time, the stepwise applied voltage value (applied voltage pattern) changed when the specified time is achieved is stored in a storage means such as a memory. In the subsequent sheet conveyance, the electromagnetic clutch may be controlled based on the stored change voltage value.

  Generally, the load characteristics of the electromagnetic clutch and the drive transmission system do not change so much within a predetermined period. Thus, by storing and diverting the voltage value (voltage pattern) converged at a predetermined specified time in this way, Subsequent conveyance control can be further simplified.

  If there are few intermediate drive transmission elements and variations in these characteristics can be ignored, the control mode as described above is performed when the first recording sheet is conveyed after the start of the apparatus. As a result, it is possible to correct the variation in the individual characteristics of the electromagnetic clutch and achieve a predetermined transport time (specified time).

  Furthermore, from the viewpoint of realizing conveyance control corresponding to changes in the characteristics of the component elements over time, the change control of the applied voltage of the electromagnetic clutch based on the paper arrival time changes the characteristics of the component elements over time from the initial use. It may be performed every predetermined period (for example, at the start of use of the apparatus and every time a predetermined number of printed sheets (for example, 10,000 sheets) is formed).

  Also in this case, the conveyance control can be simplified more than when the applied voltage of the electromagnetic clutch is changed for each conveyance of the recording paper.

1 is a schematic configuration diagram showing an embodiment of an image forming apparatus according to the present invention. 1 is a perspective view illustrating a schematic configuration of a sheet conveying device according to the present invention. It is a typical block diagram for demonstrating the control method of the electromagnetic clutch which concerns on this invention. It is a figure which shows typically the applied voltage to the electromagnetic clutch by the voltage adjustment means which concerns on this invention.

Explanation of symbols

2-5: paper tray, 12, 12R: paper transport path, 50: paper transport device, 51: pickup roll, 53: feed roll, 55: retard roll, 58a-58c, 59a-59c: transport roll pair, 58a- 58c: drive conveyance roll, 58a ₀ -58c ₀ : drive shaft, 59a-59c: driven conveyance roll, 60: cover member, 100: image forming apparatus, 102: automatic document feeder, 103: image reading unit, 104: Image forming unit, 105: paper feeding unit, 107: photosensitive drum, 108: developing roll, 109: exposure device, 110: transfer roll, 111: fixing device, 112: discharge roll, 113: discharge tray, C1, C2: Electromagnetic clutch, CR: Controller, G ₁₁ , G ₁₂ , G ₂₁ , G ₂₂ : Transmission gear, M: Motor, S: Paper sensor

Claims (5)

A pair of transport rolls facing each other and transporting the recording paper between them,
A drive shaft for driving one of the pair of transport rolls;
An electromagnetic clutch that connects the drive shaft and a drive source that drives the drive shaft through a drive transmission mechanism by applying a predetermined voltage;
An arrival time detecting means provided on the downstream side of the conveyance roll pair in the conveyance path of the recording paper, and detecting an arrival time of the recording sheet from the conveyance roll pair to a predetermined conveyance point;
Voltage adjusting means for controlling the voltage applied to the electromagnetic clutch,
The voltage adjusting means applies a stepped voltage that sequentially increases until reaching a steady value to the electromagnetic clutch, and changes and controls the stepped voltage based on a detection result of the arrival time detecting means. Paper transport device.   The voltage adjusting means reduces a stepped voltage applied to the electromagnetic clutch when the arrival time is shorter than a predetermined specified time, and applies it to the electromagnetic clutch when longer than a predetermined specified time. The sheet conveying device according to claim 1, wherein the stepped voltage is increased.   The voltage adjusting means stores in the storage means the stepped voltage value at which the specified time has been reached when the paper arrival time has converged to a predetermined specified time, and this is stored during subsequent paper transport. The paper conveying apparatus according to claim 2, wherein a voltage is applied to the electromagnetic clutch based on the measured voltage value.   The sheet according to any one of claims 1 to 3, wherein the voltage adjusting unit performs change control of the stepped applied voltage based on a detection result of the arrival time detecting unit every predetermined period. Conveying device. By applying a stepped voltage that sequentially increases until reaching a steady value, a pair of transporting rolls that face each other and transport the recording paper between them, a drive shaft that drives one of the pair of transporting rolls, Using an electromagnetic clutch that connects a shaft and a drive source that drives the drive shaft via a drive transmission mechanism,
In a state where the recording sheet is nipped between the pair of conveying rolls, the voltage application to the electromagnetic clutch is temporarily stopped, and then the recording sheet is conveyed by applying a voltage to the electromagnetic clutch. A method for controlling an electromagnetic clutch for paper conveyance, comprising: measuring the arrival time of a recording paper to a conveyance point and changing and controlling a voltage applied to the electromagnetic clutch based on the measurement result.

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