JP2008179458A - Rotary encoder, phase difference measuring device, and sending-out device and image forming device using these devices - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotary encoder, a phase difference measuring device and a sending-out device using these devices, capable of detecting relative deviation of rotation of two detecting object rotary bodies with a simple and inexpensive constitution. <P>SOLUTION: This rotary encoder has a first rotary plate rotating interlocking with the first detecting object rotary body, a second rotary plate rotating interlocking with the second detecting object rotary body, and one optical detector applying light, when arranging the first rotary plate and the second rotary plate so that its first detecting object pattern and the second detecting object pattern become a state of moving in the same direction by mutually opposing in the same position, to a first detecting object pattern and a second detecting object pattern oppositely moving in that same position, and outputting an electric signal corresponding to the quantity of light by receiving the light obtained by the light application. A phase difference detecting device outputs information on a phase difference of the two detecting object patterns from output information of this rotary encoder. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rotary encoder, a phase difference measuring device, a sending device using the same, and an image forming apparatus.

  As a transport device for transporting a sheet-shaped transported object such as recording paper to a predetermined transport destination, the transported object is transported by transporting it at a predetermined timing by a feed roll that rotates in contact with the surface of the transported object. There is something to do.

  In such a transport device, when the delivery roll is started by rotating the delivery roll, the delivery roll may slip on the surface of the delivery object and cannot be delivered at a predetermined timing. When a feeding failure due to this slip (slip) phenomenon occurs, for example, a conveyed object on which an image to be read is formed is fed one by one to an image reading apparatus for reading the image and automatically sent. In the case of an automatic document feeder that transports, there is a problem in that an image on the transported object that has been fed out and transported cannot be read normally by the image reader. Further, when an image is formed on the object to be conveyed, problems such as an image cannot be accurately formed at a predetermined position of the object to be conveyed that has been sent out and conveyed are induced.

  Conventionally, there has been known an apparatus that takes measures to reduce such a delivery failure.

  For example, an encoder as a roller detecting means for detecting the rotation speed is attached to a delivery roller for delivering paper sheets, and the roller speed is set to a roller for detecting the speed of the paper sheets delivered by the delivery roller. An encoder as a paper sheet speed detecting means to be detected is attached, a slip ratio is calculated based on the outputs of the both detecting means, and the rotational speed of the feed roller is controlled so that the slip ratio falls within the optimum slip area. There is known a paper sheet feeding apparatus constructed as described above (Patent Document 1).

  In addition, an encoder as a rotational speed detecting means for detecting the rotational speed is attached to the pickup roller that feeds out the sheet, and a roller for detecting the moving speed of the sheet by the pickup roller is used as a moving speed detecting means for detecting the speed of the roller. 2. Description of the Related Art A sheet feeding device is known in which an encoder is attached and configured to control the rotational speed of the pickup roller in accordance with the ratio between the detected value of the rotational speed detecting means and the detected value of the moving speed detecting means (patent) Reference 2).

JP-A-4-125241 JP-A-10-101238

  The present invention provides a rotary encoder, a phase difference measuring device, a sending device and an image forming apparatus using them, which can detect a relative shift in rotation between two detected rotating bodies with a simple and low-cost configuration. It is to provide.

The rotary encoder (A1) according to the present invention includes a first rotating plate that rotates in conjunction with the first detected rotating body and has a first detected pattern that transmits or reflects light;
A second rotating plate on which a second detected pattern that transmits or reflects light and rotates in conjunction with the second detected rotating body is formed;
When the first rotating plate and the second rotating plate are installed so that the first detected pattern and the second detected pattern face each other at the same position and move in the same direction, One that irradiates light toward the first detected pattern and the second detected pattern that move to face each other at the same position, receives light obtained by the irradiation, and outputs an electrical signal corresponding to the amount of light. And an optical detector.

  In the rotary encoder (A2) of the present invention, in the rotary encoder (A1), the first rotary plate and the second rotary plate are in a state where their respective rotation centers are located on the same straight line. It is installed.

  The phase difference detection device (B1) of the present invention is connected to the rotary encoder (A1, A2), and has a pulse waveform obtained by shaping an electric signal corresponding to the amount of light output from the optical detector. A rectangular pulse width ratio (= pulse width / pulse interval) is calculated, and a change amount of the pulse width ratio is calculated to calculate the first detected pattern of the first rotating plate and the second rotation. It has an arithmetic processing part which outputs the information regarding the phase difference with the 2nd to-be-detected pattern of a board.

  In the phase difference detection device (B2) according to the present invention, in the detection device (B1), the arithmetic processing unit includes a first detection pattern of the first rotating plate and a second detection of the second rotating plate. This includes an operation for calculating an initial phase difference from the pattern.

Further, the delivery device (C1) of the present invention comprises a delivery rotator that contacts the surface of a sheet-like object to be conveyed and is rotationally driven in a direction in which the object is delivered and conveyed;
A detection roll that contacts the surface of the object to be transported delivered by the delivery rotor and rotates following the movement of the object to be transported;
Correction means for correcting the delivery condition of the object to be conveyed of the delivery rotary body;
The rotary encoder according to claim 1 or 2, which is attached to a rotating shaft that rotates in conjunction with the delivery rotating body and a rotating shaft that rotates in conjunction with the detection roll.
The phase difference detection device according to claim 3 or 4 connected to the rotary encoder;
When the object to be conveyed is sent out by the sending rotator, the relative deviation of the rotation of the sending rotator and the detection roll is discriminated based on the information about the phase difference obtained from the phase difference detecting device, and the correcting means And a control means for controlling the correction operation.

  The delivery device (C2) according to the present invention is the delivery device (C1) in which the delivery rotator and the detection roll are fed out of the rotation center line of the delivery rotator and the rotation center line of the detection roll. Each projection line when projected perpendicularly to the surface of the object to be transported is placed so as to have a positional relationship included in the same straight line perpendicular to the delivery direction of the object to be transported.

  The image forming apparatus (D) of the present invention further includes an image forming unit that forms an image on a sheet-like recording medium, and a transport unit that sends the recording medium to the image forming unit and transports the recording medium. Includes the above-mentioned sending device (C1 or C2).

  According to the rotary encoder (A1), it becomes possible to detect each detected pattern of the two rotating plates with one optical detector, thereby simplifying the relative deviation of the rotation of the two detected rotating bodies. In addition, it can be detected with a low-cost configuration.

  According to the rotary encoder (A2), the two rotary plates can be installed easily and in a space-saving manner compared to the case where the present configuration is not provided.

  According to the phase difference detection device (B1), even if the encoder detects each detected pattern of the two rotating plates with one optical detector, the phase difference between the detected patterns on the two rotating plates is detected. Thereby, it is possible to obtain information on the relative deviation of the rotation of the two detected rotating bodies.

  According to the phase difference detection device (B2), it is not necessary to perform an operation (such as an origin return operation) for returning the two rotary plates to their predetermined initial reference position before performing the detection operation.

  According to the delivery device (C1), information on the relative displacement between the rotation of the delivery rotating body and the detection roll is detected with a simple and low-cost configuration, and the conveyance conditions are corrected. It is possible to easily grasp the slip state of the delivery rotating body with the object to be conveyed, and to send out the object to be conveyed well for conveyance. Further, when the sending device is a sending device in an automatic document feeding device of an image reading device, for example, the transported object on which the image to be read is formed can be sent out satisfactorily, thereby reading the image normally. It becomes possible.

  According to the delivery device (C2), the detection roll is not arranged in a positional relationship shifted from the rotational body before and after the transported object in the delivery direction, and the delivery rotational body and the detection roll are not transported. Therefore, the apparatus can be reduced in size.

  According to the image forming apparatus (D), the sheet-like recording medium is satisfactorily sent out from the conveying unit and conveyed, and for example, an image can be formed on the recording medium at an accurate position. .

[Embodiment 1]
Hereinafter, the printer according to the first embodiment will be described with reference to the drawings.

  As shown in FIG. 1, the printer 1 forms a toner image based on image information in an apparatus main body (not shown) and finally transfers the toner image onto a sheet-like recording paper 9. An image device 10, a fixing device 20 that fixes the toner image by passing the recording paper 9 onto which the toner image is transferred, and a paper feeding device 30 that conveys and supplies the recording paper 9 to the image forming device 10. Mainly equipped. A reference numeral 25 in the figure is a control device that comprehensively controls the operation and the like of each component of the printer 1, and an alternate long and short dash line with arrows indicates a main conveyance path of the paper 9.

  The image forming apparatus 10 can form and transfer a toner image using a known electrophotographic system, for example. Specifically, a cylindrical photosensitive member 12 that is rotationally driven in the direction of an arrow is provided, and a charging device 13 that uniformly charges the surface (image holding surface) of the photosensitive member 12 around the photosensitive member 12. And an exposure device 14 that irradiates the surface of the charged photoreceptor 12 with light based on image information (signals) to form a latent image having a potential difference, and toner is transferred and attached to the latent image to be visualized as a toner image. The developing device 15 that forms an image, the transfer device 16 that transfers the toner image onto the paper 9 supplied from the paper supply device 30, and the cleaning that removes and cleans the toner remaining on the surface of the photoreceptor 12 after the transfer. A device 17 is mainly arranged.

  Among these, the photoreceptor 12 is formed by forming a photoconductive layer made of an organic photosensitive material on the peripheral surface of a base material such as a cylindrical shape. As the charging device 13, a charging member such as a charging roll is installed in contact with or close to the surface of the photosensitive member 12, and a predetermined charging voltage is applied to the charging member from a power supply device (not shown). Yes. As the exposure device 14, a device constituted by an LED array, a semiconductor laser scanning device, or the like is used. The exposure device 14 is an image signal obtained by subjecting image information input from an external device such as an image reading device or a computer connected to the printer 1 to an image processing device (not shown) during image formation. Is entered.

  Further, the developing device 15 is equipped with a developing roll for transporting and supplying the contained toner to a developing position facing the photoconductor 12, and a predetermined developing voltage is supplied to the developing roll from a power supply device (not shown). Is used. As the transfer device 16, a transfer member such as a transfer roll is installed so as to be in contact with or close to the surface of the photosensitive member 12, and a predetermined transfer voltage is applied to the transfer member from a power supply device (not shown). Yes. As the cleaning device 17, a device equipped with a cleaning member such as a cleaning blade whose tip is in contact with the surface of the photoreceptor 12 after the transfer with a predetermined pressure is used.

  The fixing device 20 includes a heating roll 22 that is heated to a predetermined temperature and is driven to rotate in the direction of the arrow inside the main body 21, and pressurization that makes contact with the heating roll 22 at a predetermined pressure substantially along the axial direction of the heating roll 22. And a pressing member 23 such as a roll. Fixing by the fixing device 20 is performed by heating and pressurizing the toner image and the like by introducing and passing the paper 9 on which the toner image is transferred to the fixing contact portion between the heating roll 22 and the pressure member 23. Done.

  The paper feeding device 30 includes a paper feeding cassette 31 that accommodates a plurality of sheet-like recording papers 9 to be supplied to the image forming device 10 and a paper 9 that is accommodated in the paper feeding cassette 31. It mainly includes a delivery device 4 that feeds out one sheet at a time. A plurality of paper feed cassettes 31 are provided as necessary. Further, the paper feeding device 30 is a pair of paper transporting rolls 33, 34, 35,... For transporting the paper 9 from the paper feeding cassette 31 to the transfer section of the image forming device 10 (between the photosensitive drum 12 and the transfer device 16). And a paper conveyance path composed of guide members and the like. The sheet conveyance path is also provided between the image forming device 10 and the fixing device 30 and between the fixing device 30 and the paper discharge unit (tray or the like) 39. For example, on the paper discharge side of the fixing device 30, a discharge roll pair 36 for discharging and transporting the fixed paper 9 to the paper discharge unit 39 is installed.

  As shown in FIG. 1 and FIG. 2, the feeding device 4 in the paper feeding device 30 feeds the paper 9 in contact with the surface of the uppermost recording paper 9 loaded and accommodated in the paper feeding cassette 31. A pickup roll 41 that is rotationally driven in the transport direction A, a transport roll 42 that is rotationally driven in the direction B of transporting the paper 9 sent out by the pickup roll 41, and a direction of transporting the paper in contact with the transport roll 42 And a separation roll 43 that rotates only in the opposite direction and separates and separates the double-fed paper 9 that has been fed out by the pickup roll 41 in a superimposed manner. For example, the separation roll 43 is supported by one end portion of a support frame body 44 whose rotation shaft 43a swings around the support shaft 44a, and is elastically pressurized such as a coil spring attached to the other end portion of the support frame body 44. A predetermined pressure is applied by the member 45 so as to come into contact with the transport roll 42 at the pressure. Reference numeral 46 in FIG. 2 is a paper passage sensor for detecting the passage of the front end portion and the rear end portion of the paper 9 transported and sent by the transport roll 42.

  Basic image formation (printing) by the printer 1 is performed as follows.

  When the control device 25 of the printer 1 receives a print start command signal, the control device 25 starts a control operation, and thereby the photoreceptor 12 starts to rotate in the image forming device 10. Subsequently, after the surface of the rotating photoconductor 12 is charged to a predetermined charging potential by the charging device 13 to which a charging voltage is applied, the surface of the charged photoconductor 12 operates based on the image signal. Light is exposed from the exposure device 14 to form an electrostatic latent image having a predetermined latent image potential. Next, the electrostatic latent image is developed with toner when it passes through the developing device 15 to which a developing voltage is applied, and becomes a toner image.

  Thereafter, the toner image on the photoconductor 12 is conveyed at a predetermined timing from the paper feeding device 30 through the paper feeding path at a transfer portion facing the transfer device 16 to which a transfer voltage is applied. 9 is electrostatically transferred. At this time, the recording paper 9 is fed as follows. First, after the recording paper 9 accommodated in the paper feed cassette 31 is fed to the pickup roll 41 and separated between the transport roll 42 and the separation roll 43, the one sheet is recorded. Only the paper 9 is sent out to the paper feed path and conveyed. Subsequently, the fed sheet 9 is temporarily stopped by the alignment conveyance roll pair 35 and then sent to the transfer unit by the alignment conveyance roll pair 35 at a predetermined timing. After the transfer is completed, the photosensitive member 12 is cleaned by removing toner and paper dust remaining on the surface by the cleaning device 17.

  The sheet 9 on which the toner image is transferred is conveyed so as to be introduced into the fixing device 20, and a fixing contact portion between the heating roll 22 and the pressure member 23 that is heated and held at the fixing temperature in the fixing device 20 is formed. The toner image is fixed on the paper 9 by being heated and pressurized when passing. Thereafter, the fixed sheet 9 is discharged to the sheet discharge unit 39 through the sheet discharge path and stacked and accommodated. As a result, the basic printing operation for one sheet is completed. Further, when there are a plurality of print instructions, the above-described series of operations is similarly repeated for the number of prints.

  Further, in the printer 1, the following configuration is adopted in order to enable the recording device 4 of the paper feeding device 30 to send out a good recording paper.

  As shown in FIGS. 2 to 4 and the like, the delivery device 4 is provided with a detection roll 51 that contacts the surface of the recording paper 9 delivered by the pickup roll 41 and rotates following the movement of the paper 9 delivered. At the same time, a rotary encoder 6 that detects the relative shift of the rotation of the pickup roll 41 and the detection roll 51 is installed, and the pickup roll 41 is based on detection information obtained from the phase difference detection device 7 connected to the rotary encoder 6. The control device 55 controls the operation of the load correction mechanism 52 that corrects the load when contacting the surface of the recording paper 9.

  The pickup roll 41 moves up and down in the directions of arrows C and D so as to be movable toward and away from the surface of the uppermost recording paper 9 loaded and accommodated in the paper feed cassette 31. It is supported on the side through a holding frame 47 attached so as to swing in the directions of arrows E and G around the support shaft 47a. The pick-up roll 41 has a rotary shaft 41a fixed to the roll rotatably supported by the holding frame 47, and a gear 41b fixed to the rotary shaft 41a. Rotational power is transmitted from the rotation transmission mechanism) and is driven to rotate in the delivery conveyance direction A. The swinging support frame can swing freely in both the arrow C and D directions after being lowered in the arrow C direction. The lifting / lowering operation and the rotation operation of the pickup roll 41 are controlled by the control device 55 (FIG. 5).

  The load correction mechanism 52 is attached to the front end side of the swing support frame body, and the operating rod 53a comes into contact with the upper part of the holding frame body 47 to project and move, whereby the holding frame body 47 is moved to the recording paper 9. A solenoid 53 that swings in a pressing direction G close to the surface and a coil spring 54 that is attached so as to apply a pulling force that swings the holding frame 47 in a direction E that always contacts the operating rod 53a of the solenoid 53. It is configured. One end of the coil spring 54 is attached to an attachment portion 54 a formed on the swing support frame or solenoid 53, and the other end is attached to an attachment portion 47 b formed on the holding frame 47. In the load correction mechanism 52, when the solenoid 53 causes the operating rod 53a to project and move, the holding frame 47 swings in the direction of arrow G, and the load on the pickup roll 41 increases. The solenoid 53 can be replaced with a means for swinging the holding frame body 47 in the pressing direction G close to the surface of the recording paper 9, and for example, a voice coil motor can be used. is there.

  The detection roll 51 has the same roll diameter as the pickup roll 41, and the holding frame body 47 is arranged so that the rotation shaft 51 a fixed to the roll 51 is coaxial with the rotation shaft 41 a of the pickup roll 41. It is attached to a part of it so that it can rotate freely. As shown in the upper part and the lower part of FIG. 4, the detection roll 51 includes an axis line (rotation center line) 51 b of the rotation shaft 51 a and an axis line (rotation center line) 41 b of the rotation shaft 41 a of the pickup roll 41. The projection lines 41c and 51c are projected so as to be perpendicular to the surface of the paper 9 so that they are in a positional relationship included in the same straight line (straight line Y indicated by a two-dot chain line) orthogonal to the feeding direction A of the paper 9. ing. Here, the above-mentioned “orthogonal” refers to a state of intersecting with a reference straight line at an angle within a range of 80 ° to 100 °. The surface of the detection roll 51 has the same configuration as that of the pickup roll 41 (particularly, the detection roll 51 has a surface characteristic of a static friction coefficient with respect to the paper 9).

  3 and 7, the rotary encoder 6 is fixed to one end of the rotating shaft 51 a of the pickup roll 41 and the first rotating plate 61 that is fixedly attached to one end of the rotating shaft 41 a of the pickup roll 41 and the one end of the rotating shaft 51 a of the detection roll 51. A second rotating plate 63 to be attached, a first slit pattern 62 that transmits light formed on the first rotating plate 61, and a second slit that transmits light formed on the second rotating plate 63. The pattern 64 is mainly composed of one optical detector 65 that emits light (L), receives light (L) obtained by the irradiation, and outputs an electrical signal corresponding to the amount of light.

As shown in FIG. 8, each of the first rotating plate 61 and the second rotating plate 63 has a plurality of slits 62a and slits 64a that are opened in a rectangular shape on a disc-shaped substrate having the same diameter. And what was formed similarly is used in the state where it was arranged in the circumferential direction at equal intervals. In this embodiment, as shown in FIG. 9, the slits 62a and 64a have a size relationship in which the ratio (W ₁ : W ₂ ) between the circumferential width W ₁ and the slit interval W ₂ is 1: 2. Forming. As a result, the slit width W ₁ and the non-slit width (W ₂ −W ₁ ) are the same, and the slit interval W ₂ is twice the slit width W ₁ (W ₂ = 2W ₁ ). ing.

  In addition, the first rotating plate 61 and the second rotating plate 63 are respectively attached to the end portions of the rotating shaft 41a and the rotating shaft 51a that are in a coaxial positional relationship, so that they are spaced apart from each other. Installed in close proximity. As a result, the first slit pattern 62 and the second slit pattern 64 on each of the rotary plates 61 and 63 are placed in a state where they can face each other and move in the same direction at the same position. Incidentally, in this embodiment, from the viewpoint of rotating the first rotating plate 61 and the second rotating plate 63 having the same configuration in close proximity to each other without being shaken, FIG. As shown in FIG. 7, a configuration is adopted in which a small-diameter tip 51b of one rotating shaft 51a is rotatably supported inside the end of the other rotating shaft 41a, and the rotating shafts are connected. Yes. However, this connected configuration is not essential and may not be adopted.

  As described above, the optical detector 65 is installed on the side surface of one of the first rotating plate 61 and the second rotating plate 63 (the second rotating plate 63 in this example) having the same configuration and facing each other. A light-emitting element 66 such as a light-emitting diode that irradiates light having a high directivity (irradiation light La) toward the second slit pattern 64 and the first slit pattern 62 that move in opposition to each other; and a first rotary plate 61 and the second rotating plate 63 are placed in a state facing the side opposite to the side where the light emitting element 66 is located, and the irradiated light (La) is connected to the second slit pattern 64. It is mainly composed of a light receiving element 67 such as a phototransistor or a photodiode that receives light (transmitted light Lb) obtained by transmitting through the first slit pattern 62.

  When receiving the light, the light receiving element 67 outputs an electric signal (voltage) corresponding to the light amount. Reference numeral 68 in FIG. 7 indicates that the light emitting element 66 and the light receiving element 67 are attached to two opposing portions that are bent so as to surround the two rotating plates 61 and 63 from the outside. It is a support frame having a U-shaped cross section. The support frame body 68 is attached to a holding frame body 47 that supports the pickup roll 41.

  The phase difference detection device 7 is connected to the rotary encoder 6 (output unit thereof), and receives an electrical signal output from the light receiving element 67. The detection device 7 calculates a ratio (H) of a pulse width in a rectangular pulse waveform obtained by the waveform shaping unit 71 and a waveform shaping unit 71 that shapes the electrical signal into rectangular pulse waveform information. In addition, the amount of change in the pulse width ratio (H) is calculated, and the phase difference (S) between the first slit pattern 62 of the first rotary plate 61 and the second slit pattern 64 of the second rotary plate 63 is calculated. ) And the arithmetic processing unit 72 that outputs information.

  Of these, the waveform shaping unit 71 is configured by a known waveform shaping circuit capable of shaping an electrical signal corresponding to the amount of light into a rectangular pulse waveform. The waveform shaping unit 71 may be arranged on the rotary encoder 6 side as necessary. The arithmetic processing unit 72 operates according to an algorithm (FIGS. 12 and 14 to 15) described later. Specifically, the arithmetic processing unit 72 has a rising portion (in the rectangular pulse waveform obtained from the waveform shaping unit 71 ( Timer counter circuit that can count the elapsed time from the start of measurement until a signal) or trailing edge (signal) is detected, and the above algorithm is executed based on the count time information from this timer counter circuit An arithmetic circuit or the like that operates with a control program. The arithmetic circuit may be configured to execute and process the algorithm in the arithmetic processing unit of the control device 55. The pulse width ratio (H) is represented by H = “pulse width (ta) / pulse interval (tb)”.

  The phase difference (S) is, as shown in FIG. 9 and the like, a first slit pattern 62 and a second slit pattern 64 that are generated by a relative shift in rotation between the first rotating plate 61 and the second rotating plate 63. It shows the positional deviation amount in the circumferential direction. The relative displacement between the rotation of the first rotating plate 61 and the second rotating plate 63 is determined by the pick-up roll 41 when the rotation is started when the paper feeding by the feeding device 4 is performed with respect to the recording paper 9 to be sent. If the paper roll slips, the feeding of the paper 9 is delayed from the time when the pick-up roll 41 starts to rotate. Therefore, the detection roll 51 in contact with the paper 9 at this time also starts rotating with a delay. The phase difference (S) is represented by a pulse width ratio (H), and changes in proportion to the change (increase / decrease) in the pulse width ratio (H). is there.

  The control device 55 is configured by a microcomputer equipped with an arithmetic processing device, a storage element (device), and the like, and the phase difference detection device 7 and the load correction mechanism 52 are connected to each other. In this control device 55, the relative deviation of the rotation of the pickup roll 41 and the detection roll 51 in the delivery device 4 is determined based on the phase difference (S) obtained from the phase detection device 7, and the determination is made as will be described later. Based on the result, the correction operation of the load correction mechanism 52 is controlled as necessary. Further, as described above, the control device 55 controls not only the lifting / lowering operation and rotation operation of the pickup roll 41 but also the rotation operation of the transport roll 42 and the like. Furthermore, the control device 55 is connected to the paper passage sensor 46 described above, and receives control signals such as paper feed timing from the control device 25 that performs overall control of the entire printer. ing.

  In this embodiment, when the recording paper 9 is sent out by the pickup roll 41 of the delivery device 4, if the pickup roll 41 slips (slides) with respect to the surface of the paper 9 at the start of rotation, it contacts the paper 9. Since the detection roll 51 that has started rotating behind the pickup roll 41, the relative deviation of the rotation of the pickup roll 41 and the detection roll 51 represented by the phase difference (S) is defined as the “slip amount” of the pickup roll 41. Judging. Then, when the slip amount (phase difference S) exceeds a predetermined value (threshold value), the control device 55 operates the load correction mechanism 52 to increase the load on the pickup roll 41.

  At this time, as shown in the upper part of FIG. 6, the load is increased at a certain level regardless of the magnitude of the slip amount after exceeding the slip amount threshold value Sx, or the lower portion of FIG. As shown in FIG. 5, after the slip amount threshold value Sx is exceeded, the slip amount may be increased at different levels (stepwise indicated by a solid line or continuously indicated by a two-dot chain line K1). From the viewpoint of realizing better paper feeding, it is preferable to perform the latter. When increasing the load as in the latter case, a comparison table is prepared in advance, in which the protruding amount of the operation rod 53a of the solenoid 53 in the load correction mechanism 52 is individually determined according to the amount of slippage. The load correction mechanism 52 may be operated based on the information. When the latter weighting is performed continuously, as indicated by a two-dot chain line K2 in the lower part of FIG. 6, the load is always applied when the slip amount is detected, regardless of the slip amount threshold value Sx. You may comprise so that it may correct | amend.

  Hereinafter, the operation of the sending device 4 will be described.

  In the delivery device 4, when it is time to perform a paper feeding operation during image formation, as shown in FIG. 5, first, the pickup roller 41 is lowered by the control operation of the control device 55 (the swing support frame body of the swing support frame body). Swing in the direction of arrow C) is executed (step S10). As a result, the pickup roll 41 attached to the holding frame 47 supported on the front end side of the swinging support frame comes into contact with the surface of the uppermost recording paper 9 accommodated in the paper feed cassette 31. At the same time, the detection roll 51 attached to the holding frame 47 is also in contact with the surface of the uppermost recording paper 9 in the horizontal state (FIG. 4).

  Subsequently, after the rotary encoder 6 and the phase difference detector 7 start detecting the slip amount of the pickup roll 41 (S11), the pickup roll 41 and the transport roll 42 are started to rotate (S12).

  Strictly, the slip amount detection operation at this time is effective from the time when the pickup roll 41 starts to rotate, but at least after the pickup roll 41 and the detection roll 51 come into contact with the surface of the paper 9 and the vibration stops. Be started. As a result, the rotation state of the roll 41 and the detection roll 51 (such as the presence or absence of relative deviation) is always monitored before the pickup roll 41 starts rotating.

  In this slip amount detection operation, first, the amount of light transmitted through the two rotary plates 61 and 63 in the rotary encoder 6 is detected by one optical detector 65. At this time, the optical detector 65 is attached to the first slit pattern 62 of the first rotary plate 61 attached to the rotary shaft 41a side of the pickup roll 41 and the rotary shaft 51a side of the detection roll 51, as shown in FIG. In addition, a light amount (a pulse portion indicated by a solid line) corresponding to the slit space width (M) where the second slit pattern 64 of the second rotating plate 63 overlaps is received.

Here, in FIG. 10, for the sake of convenience, an electric signal corresponding to the amount of light obtained from the first slit pattern 62 and the second slit pattern 64 is shaped into a rectangular pulse waveform by two-dot chain lines P1 and P2. Each of them is shown after waveform shaping of an electrical signal corresponding to the amount of light obtained from the slit space width (M) into a rectangular pulse waveform (in this embodiment, obtained by the waveform shaping unit 71 of the phase difference detection device 7). (Waveform information) is indicated by a solid line P3. In FIG. 10, since the rotation of the second rotating plate 63 is relatively slower than the rotation of the first rotating plate 61, the pulse interval (W ₂ ) in the rectangular pulse waveform obtained by the optical detector 65. , And the phase difference (S) between the first slit pattern 62 and the second slit pattern 64 is gradually enlarged. A dotted arrow indicated by a symbol J in FIG. 9 indicates a delay direction of the second slit pattern 64 (second rotating plate 63) with respect to the first slit pattern 62 (first rotating plate 61).

  Subsequently, in the phase difference detection device 7, an electrical signal corresponding to the amount of light obtained by the rotary encoder 6 is shaped into a rectangular pulse waveform by the waveform shaping unit 71, and then an arithmetic processing unit based on the pulse waveform. At 72, the pulse width ratio (H) is calculated.

At this time, both the first slit pattern 62 and the second slit pattern 64 have a relationship (W ₂ = 2W ₁ ) in which the slit interval W ₂ is twice the slit width W ₁ as described above. The phase difference (S) between the two slit patterns theoretically changes as the pulse width ratio (H = ta / tb) changes as shown in FIG. In particular, the ratio (H) of the pulse width is the maximum value (W ₁ / W ₂ = 0.5) when the two slit patterns are shifted to the maximum, and the minimum value (W) when the two slit patterns are completely matched. ₁ / W ₂ = 0), and the change between the maximum value and the minimum value is repeated so as to be repeated in the cycle of the slit width W ₁ . For this reason, the phase difference (S) cannot be specified only by the value of the pulse width ratio (H). The symbol n shown at the bottom in FIG. 11 is an integer, and indicates one cycle until the pulse width ratio (H) changes from the maximum value to the minimum value and then reaches the maximum value again. Further, “n = 0” indicates a range corresponding to the first cycle, and “n = 1” indicates a range corresponding to the next cycle.

Therefore, in the phase difference detection device 7, the arithmetic processing unit 72 first calculates the initial phase difference (Si) between the first slit pattern 62 and the second slit pattern 64. To calculate the initial phase difference (Si), the initial phase difference (Si) is in a transition process (direction) in which the value of the pulse width ratio (H) at the start of the slip amount detection operation is decreased (0 on the horizontal axis in FIG. 11). to _W-1 is a value in the interval indicated by) or, or, or not in the transition process of increasing (direction) (which is a value in the interval represented by W ₁ ~2W ₁ on the abscissa in FIG. 11) It is necessary to determine about. Accordingly, for the initial phase difference (Si), at the start of the slip amount detection operation, first, at least two pulse width ratios (H) (H1, H2) are obtained, and the two ratios (H1, H2). The amount of change (dH = H2−H1) is calculated.

  FIG. 12 shows an algorithm for calculating the initial phase difference (Si).

  When calculating the initial phase difference (Si), first, after initializing the variables (phase difference S, integer n) (step S101), the timer counter circuit starts timer count (tc: count value). (S102), the rise (i) of the pulse portion in the pulse waveform (solid line P3) shown in FIG. 12 is detected (S103).

The detection of the rising edge (i) is performed only while the predetermined time td is set and the predetermined time elapses. Here, when the rising edge (i) of the pulse cannot be detected within the predetermined time, the rotation of the first rotating plate 61 and the second rotating plate 63 is too slow to be detected or the two slit patterns 62 and 64 are detected. Is when the pulse width ratio (H) is zero (when the phase difference S is in the slit width W ₁ state) and the pulse width ratio (H) at any time. Since the timer count value tc is returned to zero, the above operation is repeated until the rising edge (i) of the pulse can be detected.

  After the rising edge (i) of the pulse is detected in step S103, the timer count value tc is returned to zero and the timer count is started (S104), and the pulse waveform (solid line) shown in FIG. The trailing edge (ii) of the pulse part in P3) is detected (S105).

  At this time, if the falling edge (ii) of the pulse cannot be detected within the predetermined time, the rotational difference between the first rotating plate 61 and the second rotating plate 63 is small, and the phase difference between the two slit patterns 62 and 64 is detected. Since the pulse width ratio (H) cannot be detected at this time, the timer count value tc is returned to zero, and the above-described detection of the rising edge (i) is repeated.

  After the falling edge (ii) of the pulse is detected in step S105, the timer count value tc at that time is determined as “ta” of the pulse width, and then the timer count is started after the count value tc is returned to zero. Then, within the elapse of the predetermined time td, the rise (iii) of the subsequent pulse portion in the pulse waveform (solid line P3) shown in FIG. 13 is detected (S107). When the rising edge (iii) of the pulse cannot be detected within the predetermined time, the rotational deviation between the first rotating plate 61 and the second rotating plate 63 is small, and the change in the phase difference between the two slit patterns 62 and 64 is small. At this time, since the pulse width ratio (H) cannot be detected, the timer count value tc is returned to zero, and then the above-described detection of the rising edge (i) is performed again.

  After the rising edge (iii) of the pulse is detected in step S107, the timer count value tc at that time is added to the previous pulse width ta to determine the pulse interval “tb (= ta + tc)”. The first ratio (H1) of the width is calculated as “H1 = ta / tb)” (S108).

  Subsequently, the timer count value tc is returned to zero to start the timer count (S109), and the subsequent falling (iv) of the pulse portion in the pulse waveform (solid line P3) shown in FIG. 13 within the elapse of the predetermined time td. Is detected (S110). When the rising edge (iv) of the pulse cannot be detected within the predetermined time, the rotational deviation between the first rotating plate 61 and the second rotating plate 63 is small, and the change in the phase difference between the two slit patterns 62 and 64 is small. At this time, since the pulse width ratio (H) cannot be detected, the timer count value tc is returned to zero, and then the above-described detection of the rising edge (i) is performed again.

  After the rising edge (iv) of the pulse is detected in step S110, the timer count value tc at that time is determined as “ta” of the pulse width, and then the count value tc is returned to zero to start the timer count. (S111) Within the elapse of the predetermined time td, the rise (v) of the subsequent pulse portion in the pulse waveform (solid line P3) shown in FIG. 13 is detected (S112). When the rising edge (v) of the pulse cannot be detected within the predetermined time, the rotational deviation between the first rotating plate 61 and the second rotating plate 63 is small, and the change in the phase difference between the two slit patterns 62 and 64 is small. At this time, since the pulse width ratio (H) cannot be detected, the timer count value tc is returned to zero, and then the above-described detection of the rising edge (i) is performed again.

After the rising edge (v) of the pulse is detected in step S112, the timer count value tc at that time is added to the previous pulse width ta to determine the pulse interval “tb (= ta + tc)”. The second ratio (H2) of the width is calculated as “H2 = ta / tb)” (S113).
Next, it is determined whether or not the second pulse width ratio (H2) thus obtained is the same as the first pulse width ratio (H1) (S114). At this time, when H2 = H1, there is no change in the phase difference between the two slit patterns 62 and 64, and the initial phase difference (Si) cannot be specified. It returns to the process (S109-S113) of calculating the ratio (H2).

  When H2 ≠ H1, after calculating the difference (dH = H2-H1) between the ratio (H2) of the second pulse width (H2) and the ratio (H1) of the first pulse width (S115), The magnitude relationship between the two is determined (S116).

If it is determined in step S116 that the difference (dH) is a negative value and the second pulse width ratio (H2) is smaller than the first pulse width ratio (H1), the initial phase difference ( It can be seen that Si) is in the transition process in the section indicated by “0 to W ₁ ” on the horizontal axis in FIG. 11, and the initial phase difference (Si) at this time is “W ₁ −W ₂ · H2”. ”Is calculated (S117).

In this case, the initial phase difference (Si = W ₁ −W ₂ · H2) is replaced with the preceding phase difference (Sb), and the second pulse width ratio (H2) is replaced with the preceding pulse width ratio. After replacing (H1) (S118), the calculation process (step B) shown in FIG. 14 is continued to detect the original phase difference (S) based on the initial phase difference.

On the other hand, if it is determined in step S116 that the difference (dH) is a positive value and the second pulse width ratio (H2) is greater than the first pulse width ratio (H1), the initial position is determined. It can be seen that the phase difference (Si) is in the transition process in the section indicated by “W _{1 to} 2W ₁ ” on the horizontal axis in FIG. 11, and the initial phase difference (Si) at this time is “W ₁ + W _2. Calculated as “H2” (S119).

In this case, the initial phase difference (Si = W ₁ + W ₂ · H2) is replaced with the preceding phase difference (Sb), and the second pulse width ratio (H2) is replaced with the preceding pulse width ratio ( After the replacement as H1) (S120), the calculation process (step C) shown in FIG. 15 is continued to detect the original phase difference (S) based on the initial phase difference.

  The calculation process (step B) shown in FIG. 14 is basically the same as the calculation process shown in FIG. 12 (steps S109 to S116 in FIG. 12), and detects the pulse width “ta” and the pulse interval “tb”. The calculation of the difference (dH) between the calculation of the ratio (H2) of the pulse width that is the original detection target and the ratio (H1) of the initial phase difference of the ratio (H2) and the size determination are performed ( Steps S202 to S210 in FIG.

14 is different from the calculation process shown in FIG. 12 in that the rise (i), (iii), and fall of the pulse waveform P3 to be detected in steps S203, S205, and S207 ( If ii) cannot be detected within the lapse of the predetermined time td, the calculation process of step B is performed again from the beginning, and the calculation of the ratio (H2) of the pulse width to be detected is repeated. This is because when the above detection cannot be performed, the phase difference (S) is reduced until it cannot be detected, or the phase difference (S) is in the state of (2n + 1) W ₁ (H = 0). However, this is done because it is determined that the phase difference cannot be detected.

In the arithmetic processing shown in FIG. 14, in step S210, the difference (dH) between the pulse width ratio (H2) to be detected and the initial phase difference pulse width ratio (H1) becomes a negative value. When it is determined that the target pulse width ratio (H2) is smaller than the initial phase difference pulse width ratio (H1), the detection target phase difference (S) is determined from the maximum value of the pulse width ratio (H). It found to be of value present in the course of the interval at which the transition to the minimum value, the phase difference of the time (S) is calculated as _{"(2n + 1) W 1 -W} 2 · H2-Si " (S211).

Information on the phase difference (S = (2n + 1) W ₁ −W ₂ · H ₂ −Si) obtained at this time is transmitted to the control device 55. At the same time, the phase difference detector 7 replaces the detected pulse width ratio (H2) with the preceding pulse width ratio (H1) (S212), and then executes step S204 (circled in FIG. 14). Returning to the surrounding “D” step position), the falling (ii) of the pulse part and the rising (iii) of the next pulse part in the subsequent pulse waveform are detected, and the ratio of the next pulse width (H2) Calculation of the phase difference (S) is continued until stop control is entered. Here, the reason why the steps S202 to S203 are omitted is that the rise of the pulse necessary for starting the counting of the pulse width: ta has already been detected in the step S207 (FIG. 14), and is unnecessary. .

On the other hand, in step S210, the difference (dH) between the pulse width ratio (H2) to be detected and the initial phase difference ratio (H1) is a positive value, and the detection target pulse width ratio (H2) is the initial value. When it is determined that the pulse width ratio (H1) of the phase difference is larger than the phase difference (H1), the process within the interval when the phase difference (S) to be detected changes from the minimum value to the maximum value of the pulse width ratio (H) The phase difference (S) at this time is calculated as “(2n + 1) W ₁ + W ₂ · H 2 —Si” (S 213).

Information on the phase difference (S = (2n + 1) W ₁ + W ₂ · H ₂ −Si) obtained at this time is transmitted to the control device 55. At the same time, the phase difference detection device 7 replaces the detected pulse width ratio (H2) with the preceding pulse width ratio (H1) (S214), and then performs the calculation process (step C) in FIG. Control of stopping the calculation of the ratio (H2) of the pulse width in the subsequent pulse waveform, and hence the calculation of the phase difference (S), in step S304 in FIG. 15 (step position of “E” circled in FIG. 15). Continue until. Here, when the pulse waveform is continuously measured, the transition to Step E in FIG. 15 by interruption is that the rise of the pulse necessary for starting the counting of the pulse width: ta has already occurred in Step S207 (FIG. 14). This is because it has been detected.

  Next, the calculation process (step C) shown in FIG. 15 is basically similar to the calculation process (steps S202 to S310 and S215 of step B) shown in FIG. Detection of “tb”, calculation of the ratio (H2) of the pulse width that is the original detection target, calculation of the difference (dH) between the ratio (H1) of the initial phase difference of the ratio (H2), and magnitude determination (Steps S302 to S310 in FIG. 15).

15 is different from the calculation process shown in FIG. 14 in the difference between the pulse width ratio (H2) to be detected in step S310 and the initial phase difference ratio (H1) (step S310). dH) is a negative value, and it is determined that the detection target pulse width ratio (H2) is smaller than the initial phase difference pulse width ratio (H1), the detection target phase difference (S) is the pulse width. It can be seen that the phase difference (S) is “(2n + 1) W ₁ + W _2. Calculated as “H2-Si” (S311).

Information on the phase difference (S = (2n + 1) W ₁ + W ₂ · H ₂ −Si) obtained at this time is transmitted to the control device 55. At the same time, the phase difference detection device 7 replaces the detected pulse width ratio (H2) with the preceding pulse width ratio (H1) (S312), and then performs step S304 (circled in FIG. 15). Returning to the step position of “E” that surrounds, the falling (ii) of the pulse part and the rising (iii) of the next pulse part in the subsequent pulse waveform are detected, and the ratio of the next pulse width (H2) Calculation of the phase difference (S) is continued until stop control is entered.

On the other hand, in step S310, the difference (dH) between the pulse width ratio (H2) to be detected and the initial phase difference ratio (H1) is a positive value, and the detection target pulse width ratio (H2) is the initial value. When it is determined that the pulse width ratio (H1) of the phase difference is larger than the phase width (H1), the process in the interval when the phase difference (S) to be detected changes from the maximum value to the minimum value of the pulse width ratio (H) The phase difference (S) at this time is calculated as “(2n + 1) W ₁ −W ₂ · H ₂ —Si” (S 313).

Information on the phase difference (S = (2n + 1) W ₁ −W ₂ · H ₂ −Si) obtained at this time is transmitted to the control device 55. At the same time, the phase difference detecting device 7 adds an integer “n” indicating the number of cycles by “1” (S313), and the detected pulse width ratio (H2) is preceded by the preceding pulse width. (S314), the process proceeds to step S204 (step position of “E” circled in FIG. 15) in the calculation process (step B) of FIG. The calculation of the pulse width ratio (H2), and thus the calculation of the phase difference (S), is continued until stop control is entered. Here, the reason for shifting to step D in FIG. 14 by interruption is that the rising edge of the pulse necessary for starting the counting of the pulse width: ta has already been detected in step S307 (FIG. 15).

  When the slip amount information based on the phase difference (S) obtained by the phase difference detection device 7 as described above is transmitted to the control device 55, the control device 55 sets a predetermined threshold (Sx) for the slip amount. It is determined whether or not it exceeds (step S13 in FIG. 5).

  At this time, if it is determined that the slip amount does not exceed the threshold value, it is considered that the pickup roll 41 does not slide at all with respect to the uppermost recording sheet 9 or is slipped by a very small amount. The delivery operation continues.

  In this case, the pick-up roll 41 that has started rotating as described above feeds at least the uppermost recording paper 9 in the paper feed cassette 31 toward the transport roll 42 as desired. After that, among the fed paper 9, the paper (the paper located on the lower side) for the double feed between the transport roll 42 and the separation roll 43 is stopped while the uppermost sheet 9 Sheet 9 is sent out from the delivery device 4 by the transport roll 42.

  On the other hand, if it is determined in step S13 that the slippage amount exceeds the threshold value, it is assumed that the pickup roll 41 is slipping more than a predetermined amount with the uppermost recording paper 9, and the control device 55 performs the control operation. The load of the pickup roll 41 is corrected by the load correction mechanism 53 (S14).

  In this case, the solenoid 53 in the load correction mechanism 53 is actuated to cause the operating rod 53a to project and move by a predetermined amount according to the amount of increase in load. As a result, the holding frame 47 swings downward in the direction of arrow G about the support shaft 47 a, so that the pickup roll 41 attached to the holding frame 47 is strong against the surface of the uppermost recording sheet 9. Pressed and the load F on the roll is increased. Due to this increase in load, the feeding force (conveying force) by the pickup roll 41 is well transmitted to the uppermost sheet 9 and the slip phenomenon is prevented. Thereafter, the uppermost sheet 9 slides on the pickup roll 41. It is sent out without any problems. Thereafter, a feeding operation similar to the above-described normal paper feeding operation is performed.

  Further, in this case, when the leading end 9a of the paper 9 sent out by the pickup roll 41 whose load is increased is sent out from the transport roll 42, the passage is detected by the paper passage sensor 46 (S15). The load correction of the pickup roll 41 by the load correction mechanism 53 is released (S16). That is, the solenoid 53 in the load correction mechanism 53 is activated, and the operating rod 53a is pulled into the main body to return to the normal position.

  In the delivery device 4, when it is confirmed that the uppermost recording sheet 9 has been delivered satisfactorily as described above (S17), after the rotational drive of the pickup roll 41, the transport roll 42, etc. is stopped. (S18) The detection operation of the slip amount of the pickup roll 41 by the rotary encoder 6 and the phase difference detection device 7 is stopped (S19), and the upward movement of the pickup roll 41 (in the direction of arrow D of the swing support frame body). (S20).

  Thus, the feeding operation of one recording sheet 9 by the sending device 4 is completed.

[Other embodiments]
In the first embodiment, as the first rotary plate 61 and the second rotary plate 63 in the rotary encoder 6, the slit width W ₁ and the slit interval W ₂ between the first slit pattern 62 and the second slit pattern 64 are any. Also, it is possible to use the one set in the relationship of “W ₂ > 2W ₁ ”.

In this case, as shown in FIG. 16, in the phase difference detection device 7 connected to the rotary encoder 6, the ratio (H) of the pulse width in the pulse waveform to be detected is the slit width of the phase difference (S). W ₁ and becomes an odd multiple of a position time which is not periodically detected in the vicinity of which may (dead region Q) occurs. However, if it is used with the knowledge that there is this insensitive region Q, the phase difference can be detected by the phase difference detecting device 7 and the load can be corrected by the sending device 4 although the accuracy may be lowered.

In the first embodiment, as the first rotary plate 61 and the second rotary plate 63 in the rotary encoder 6, the slit width W ₁ and the slit interval W ₂ between the first slit pattern 62 and the second slit pattern 64 are used. It is also possible to use those in which both are set in the relationship of “W ₂ <2W ₁ ”.

In this case, as shown in FIG. 17, in the phase difference detection device 7 connected to the rotary encoder 6, the pulse width ratio (H) in the pulse waveform to be detected is “(( In the section R in which the odd number times W ₁ ”from W ₂ −W ₁ ), two are periodically detected. However, if two pulse width ratios (H) are set to be calculated in advance, the calculation processing amount increases accordingly, but the phase difference detection by the phase difference detection device 7 and the load correction by the sending device 4 are performed. be able to.

  In the first embodiment, as shown in FIG. 18, one slit pattern (62, 64) from the light emitting element 66 is used as the first rotating plate 61 and the second rotating plate 63 in the rotary encoder 6. It is also possible to use a light reflection type detected pattern (69) that reflects the irradiation light (L). In this case, as illustrated in FIG. 18, the light emitting element 66 and the light receiving element 67 of the optical detector 65 are arranged side by side on the side surface of the second rotating plate 63, for example, and then the optical detector 65 What is necessary is just to form the said light reflection type detected pattern (69) in the rotating plate (this example 1st rotating plate 61) arrange | positioned at a far side.

  Further, in the first embodiment, the case where the load changing mechanism 52 that corrects the load on the roll according to the slip amount of the pickup roll 41 is applied, but instead of the load correction mechanism 52, the pickup roll 41 It is possible to employ means for correcting other delivery conditions that can prevent slipping. For example, a means for changing the rotation speed of the roll 41 according to the slip amount of the pickup roll 41 (usually increasing the speed) can be applied.

  Further, in the first embodiment, as shown in FIG. 19, a detection roll 51 </ b> B having a smaller diameter than the pickup roll 41 may be used as the detection roll 51. In this case, when the sheet 9 is fed by the pickup roll 41, the inertial force when the detection roll 51B in contact with the sheet 9 starts to rotate is reduced by the small diameter. The sending load for the record 9 is reduced.

  Further, in this case, the rotation shaft 41a of the pick-up roll 41 and the rotation shaft 51a of the detection roll 51B face each other at the same position as in the first embodiment (FIG. 3) and are coaxial. It is not in the positional relationship. For this reason, the rotary encoder 6 is used when the first rotary plate 61 and the second rotary plate 63 to be attached to the rotary shafts 41a and 51a are rotated in the same axis and face each other. The rotation shafts 41a and 51a and the first rotary plate 61 and the second rotary plate 63 may be connected to each other by, for example, a gear-type rotation transmission mechanism 80.

  Specifically, the rotary shaft 81 for fixing the first rotary plate 61 and the rotary shaft 82 for fixing the second rotary plate 63 are opposed to the holding frame body 47 so as to be the same axis. The rotary shaft 81 and the rotary shaft 41a of the pickup roll 41 are connected to each other by a first gear 83 and a second gear 84 attached to the shafts 81 and 41a, respectively. And the rotation shaft 51a of the detection roll 51B are connected by a third gear 85 and a fourth gear 86 attached to the shafts 82 and 51a, respectively. At this time, regarding the diameter and the number of teeth of the first gear 83 and the second gear 84 and the diameter and the number of teeth of the third gear 85 and the fourth gear 86, the pickup roll 41 and the small diameter detection roll 51 </ b> B are on the sheet 9. , The rotary shaft 81 and the rotary shaft 82 that rotate with the rotational force (speed) transmitted from the rotating rolls 41 and 51B via the gears, and thus the first rotary plate 61 and the second Are set so as to satisfy the condition that the rotating plate 63 rotates in the same direction at the same speed (circumferential speed). Thereby, the 1st rotation board 61 and the 2nd rotation board 63 come to rotate interlockingly so that it may synchronize with each rotation of the pick-up roll 41 and the detection roll 51B.

  In addition, as shown in the upper and lower parts of FIG. 20, the rotary encoder 6 is a first rotating plate 63 that is attached to the detection roll 51 (B) so as to be able to be interlocked, and is attached to the pickup roll 41. The second rotating plate 63B having a smaller diameter than the rotating plate 61 may be used.

  In this case, the second rotating plate 63B and the first rotating plate 61 having a small diameter are divided into the second slit pattern 64 of the second rotating plate 63B and the first slit pattern 62 of the first rotating plate 61. What is necessary is just to install so that it may be in the state which moves mutually in the same direction (for example, sending out conveyance direction A) in the same position. The optical detector 65 is arranged at a position where the light emitting element 66 and the light receiving element 67 can irradiate and receive light (L) at the same position where the two slit patterns 64 and 62 move opposite to each other. do it. The rotary encoder 6 having such a configuration can be effectively applied to, for example, the configuration example using the small-diameter detection roll 51B (FIG. 19).

  As shown in the upper and lower parts of FIG. 21, the rotary encoder 6 includes a first rotating plate 61 that is attached to the pickup roll 41 so as to be interlocked, and a second rotating plate 63 that is attached so as to be interlocked with the detection roll 51. Further, it may be arranged in a positional relationship that moves back and forth with respect to the feeding direction of the paper 9.

  In this case, the first rotary plate 61 and the second rotary plate 63B are the same, and the first slit pattern 62 of the first rotary plate 61 and the second slit pattern 64 of the second rotary plate 63B are the same. What is necessary is just to install so that it may become a state which mutually opposes in a position and moves to the same direction. In this example, with respect to the first rotating plate 61 that rotates in the same feeding and conveying direction A as the pick-up roll 41, for example, a rotation transmitting mechanism is interposed between the second rotating plate 63 and the detection roll 51. It is configured to rotate in the direction of arrow I. The optical detector 65 is arranged at a position where the light emitting element 66 and the light receiving element 67 can irradiate and receive light (L) at the same position where the two slit patterns 64 and 62 move opposite to each other. do it. The rotary encoder 6 having such a configuration can be effectively applied to, for example, the delivery device 4 in which it is difficult to install the detection roll 51 at a position directly beside the pickup roll 41.

  In the first embodiment, the phase difference detection device 7 may be configured as a device integrated with the same support frame as the rotary encoder 6.

  In the first embodiment, the rotary encoder 6 and the phase difference detection device 7 are applied to the sending device 4 in the paper feeding device 30 of the printer as the image forming device. However, the configuration is independent of the image forming device. The present invention may be applied to a delivery device in the paper feeding device. If necessary, for example, the image forming apparatus can be applied to a sheet conveying device of an alignment sending roll pair (for example, the roll pair 35 in FIG. 1), or a hole forming process and a binding process can be performed on a sheet after image formation. The present invention may be applied to a paper conveying device (feeding device) of a post-processing device that performs post-processing such as the above. Furthermore, the present invention may be applied to a sending device in an automatic document feeder applied to an image reading device. In addition to these, the feeding device is not limited to feeding sheet-like recording paper used for image formation, and the rotary encoder 6 and the phase difference detection device 7 are applied to rotate the feeding roll and the detection roll relative to each other. If it is necessary to correct the sending conditions based on the result of determining the misalignment, other sheet-like objects may be sent out.

  In the first embodiment, a roll-type pickup roll 41 is applied as the delivery device 4, but the present invention is not limited to this. For example, as shown in FIG. 22, a belt-type delivery belt is used. 48 may be used. The delivery belt 48 is wound around the drive roll 48 and the driven roll 50 with a predetermined pressure. When the paper 9 is delivered, the delivery belt 48 is moved downward to come into contact with the surface of the uppermost recording paper 9 to be delivered. After that, the drive roll 48 rotates to rotate in the feed and transport direction A. In the drawing, reference numeral 49 a denotes a rotating shaft fixed to the drive roll 49, and 50 a denotes a rotating shaft fixed to the driven roll 51.

  In the delivery device 4 to which such a delivery belt 48 is applied, as shown in FIGS. 22 and 23, the detection roll 51 is driven by, for example, the axis (rotation center line) 51b of the rotation shaft 51a and the delivery belt 48. Each projection line when the axis (rotation center line) 49c of the rotation shaft 49a of the roll 49 is projected perpendicularly to the surface of the recording paper 9 is included in the same straight line (Y) orthogonal to the feeding direction A of the paper 9. It can be installed in a positional relationship. Then, the rotary encoder 6 to be mounted on the delivery device 4 may have its rotating plate 61 attached to the rotating shaft 49 a of the drive roll 49.

  Further, the type of printer that forms a single color toner image is exemplified as the image forming apparatus. However, the type of printer that forms a color image composed of a plurality of toner images, a copying machine, a facsimile machine, and the like Can also be adopted. Further, as a method for forming a toner image and transferring it to the paper 9, another conventionally known method can be adopted. The image forming apparatus is not limited to a system that forms a toner image, and may be an image forming apparatus that employs another image forming system, for example, an image forming apparatus that employs an inkjet system. .

2 is an explanatory diagram illustrating an overview of a printer according to Embodiment 1. FIG. FIG. 2 is an explanatory diagram illustrating a feeding device (including a rotary encoder and a phase difference detection device) in the paper feeding device of the printer of FIG. 1. It is a schematic explanatory drawing which shows the state which looked at the principal part of the sending apparatus of FIG. 2 from the right side of the same figure. It is explanatory drawing which shows the positional relationship etc. of a pick-up roll and a detection roll. 3 is a flowchart showing a flow of a sheet feeding operation of the sending device (including a rotary encoder and a phase difference detection device) in FIG. 2. It is explanatory drawing which shows the structural example of the load correction | amendment by a load correction mechanism. It is a schematic explanatory drawing which shows the rotary encoder applied to the sending apparatus of FIG. It is a schematic explanatory drawing which shows the 1st rotating plate and 2nd rotating plate which are used for the rotary encoder of FIG. It is explanatory drawing which shows typically each slit pattern in the 1st rotary plate of FIG. 8, and its position shift state. It is explanatory drawing which shows the structure of the pulse waveform etc. which are obtained with the electric signal output from the rotary encoder of FIG. It is explanatory drawing which shows the transition state of ratio of the pulse width obtained based on the pulse waveform of FIG. It is a flowchart which shows the algorithm which calculates the initial phase difference by a phase difference detection apparatus. It is explanatory drawing which shows the rise and fall of the pulse in the pulse waveform detected with a phase difference detection apparatus. It is a flowchart which shows the algorithm regarding a part of operation | movement when detecting the original phase difference after detecting an initial phase difference. It is a flowchart which shows the algorithm regarding the other part of operation | movement when detecting the original phase difference after detecting an initial phase difference. It is explanatory drawing which shows the transition state of the ratio of the pulse width based on the pulse waveform obtained with the rotary encoder of the other example which uses the rotary plate in which the slit pattern of different conditions was formed. It is explanatory drawing which shows the transition state etc. of the ratio of the pulse width based on the pulse waveform obtained with the rotary encoder of the other structural example using the rotary plate in which the slit pattern of different conditions was formed. It is a schematic explanatory drawing which shows the rotary encoder of the other structural example using the rotating plate and optical detector of different conditions. It is a schematic explanatory drawing which shows the principal part of the other rotary encoder and delivery apparatus which attach and use a rotary plate with a different structure. It is a schematic explanatory drawing which shows the principal part of the rotary encoder of the other structural example which arrange | positions and uses a rotary plate on different conditions. It is a schematic explanatory drawing which shows the principal part of the rotary encoder of the other structural example which arrange | positions and uses a rotary plate on different conditions. It is explanatory drawing which shows the principal part of the other structural example of a sending apparatus (a rotary encoder and a phase difference detection apparatus are included). It is explanatory drawing which shows the positional relationship of the delivery belt and detection roll in the delivery apparatus of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Printer (image forming apparatus), 4 ... Sending apparatus, 6 ... Rotary encoder, 7 ... Phase difference detection apparatus, 9 ... Recording paper (sheet-like conveyed object or recording paper), 10 ... Image forming apparatus (image forming) Part), 30... Paper feeding device (paper feeding part), 41... Pickup roll (first detected rotating body, delivery roll), 51... Detecting roll (second detected rotating body, detection roll), 52 ... load correction mechanism (correction means), 55 ... control device (control means), 65 ... optical detector, 72 ... arithmetic processing section, A ... delivery conveyance direction, H ... ratio of pulse width, ta ... pulse width, tb ... Pulse interval, dH: change amount of pulse width ratio, S: phase difference, Si: initial phase difference.

Claims (7)

A first rotating plate on which a first detected pattern that transmits or reflects light and rotates in conjunction with the first detected rotating body is formed;
A second rotating plate on which a second detected pattern that transmits or reflects light and rotates in conjunction with the second detected rotating body is formed;
When the first rotating plate and the second rotating plate are installed so that the first detected pattern and the second detected pattern face each other at the same position and move in the same direction, One that irradiates light toward the first detected pattern and the second detected pattern that move to face each other at the same position, receives light obtained by the irradiation, and outputs an electrical signal corresponding to the amount of light. A rotary encoder comprising: an optical detector;   2. The rotary encoder according to claim 1, wherein the first rotary plate and the second rotary plate are installed such that their rotation centers are positioned on the same straight line. Connected to the rotary encoder according to claim 1 or 2,
The pulse width ratio (= pulse width / pulse interval) in a rectangular pulse waveform obtained by shaping the electrical signal corresponding to the amount of light output from the optical detector is calculated, and the change in the pulse width ratio An arithmetic processing unit that calculates an amount and outputs information related to a phase difference between the first detected pattern of the first rotating plate and the second detected pattern of the second rotating plate is provided. Phase difference detection device.   The rank according to claim 3, wherein the arithmetic processing unit includes an operation of calculating an initial phase difference between the first detected pattern of the first rotating plate and the second detected pattern of the second rotating plate. Phase difference detection device. A sending rotator that contacts the surface of the sheet-like object to be conveyed and rotationally drives in a direction in which the object is conveyed and conveyed;
A detection roll that contacts the surface of the object to be transported delivered by the delivery rotor and rotates following the movement of the object to be transported;
Correction means for correcting the delivery condition of the object to be conveyed of the delivery rotary body;
The rotary encoder according to claim 1 or 2, which is attached to a rotating shaft that rotates in conjunction with the delivery rotating body and a rotating shaft that rotates in conjunction with the detection roll.
The phase difference detection device according to claim 3 or 4 connected to the rotary encoder;
When the object to be conveyed is sent out by the sending rotator, the relative deviation of the rotation of the sending rotator and the detection roll is discriminated based on the information about the phase difference obtained from the phase difference detecting device, and the correcting means And a control unit that controls the correction operation.   Projection lines when the rotation center line of the delivery rotation body and the rotation center line of the detection roll are projected perpendicularly to the surface of the object to be delivered, the delivery rotation body and the detection roll. The transport apparatus according to claim 5, wherein the transport apparatus is installed so as to have a positional relationship included in the same straight line orthogonal to the delivery direction of the transported object. An image forming unit that forms an image on a sheet-like recording medium, and a transport unit that sends and transports the recording medium to the image forming unit,
An image forming apparatus, wherein the transport unit includes the sending device according to claim 5.

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