JP7329184B2 - Sheet conveying device and image forming device - Google Patents

Description

The present invention relates to a sheet conveying device and an image forming apparatus.

2. Description of the Related Art Conventionally, there has been known a drive control device having control means for controlling a plurality of drive sources for driving the same drive object.

For example, in Patent Document 1, in a drive control device that controls two motors (driving sources) that drive a rotating body (the same driven object), when one of the motors fails, only the other motor performs the rotation. It is disclosed to control the body to drive.

However, conventional drive control devices that control a plurality of drive sources for driving sheet conveying members, which are the same drive target, do not perform control aimed at saving energy or extending the life of the drive sources.

In order to solve the above-described problems, the present invention provides a sheet conveying apparatus comprising a plurality of drive sources for driving the same sheet conveying member , and control means for controlling the plurality of drive sources , wherein: Based on the type specifying information of the sheet conveyed by the same sheet conveying member or the driving speed information of the same sheet conveying member, the control means determines that the driving load applied to the same sheet conveying member is equal to or greater than a predetermined value. When the first condition is satisfied, the first driving mode in which the same sheet conveying member is driven by the plurality of driving sources is selected and executed , and the driving load applied to the same sheet conveying member is less than the predetermined value. A second drive mode in which the same sheet conveying member is driven by some of the plurality of drive sources is selected and executed when a certain second condition is satisfied .

According to the present invention, it is possible to save energy and extend the life of the drive sources in controlling a plurality of drive sources that drive the sheet conveying member, which is the same object to be driven.

1 is a schematic configuration diagram of a printer according to an embodiment; FIG. FIG. 4 is a schematic explanatory diagram of an image forming unit for yellow among four image forming units in the same printer; FIG. 2 is an explanatory diagram of the vicinity of the side frame when the side frame is opened from the printer in the state of FIG. 1; FIG. 2 is a schematic configuration diagram of a paper feeding device in the same printer; FIG. 4 is an explanatory view showing a driving device that drives a feed roller of the sheet feeding device; 1 is a block diagram showing an example of a conventional drive control device; FIG. 1 is a block diagram showing an example of a drive control device according to an embodiment; FIG. 1 is a block diagram of a drive control device according to an embodiment; FIG. FIG. 4 is a block diagram of the drive control device when executing the second mode that drives only the first motor; FIG. 11 is a block diagram of the drive control device when executing the third mode that drives only the second motor; 4 is a flowchart showing an example of a mode selection procedure according to the embodiment; 4 is a flow chart showing the flow of control during execution of the second mode or third mode in which the feed roller is driven by only one motor; FIG. 4 is an explanatory diagram showing the display contents of a touch panel, which is a printer operation unit, when a user selects paper type information; FIG. 5 is an explanatory diagram showing the display contents of the touch panel when the user selects the transport speed; FIG. 4 is an explanatory diagram showing the display contents of a touch panel displayed when notifying a user of a motor failure;

An embodiment in which the drive control apparatus of the present invention is applied to a color laser printer (hereinafter simply referred to as "printer 500"), which is a tandem image forming apparatus in which a plurality of photosensitive members are arranged in parallel, will be described below. Description will be made with reference to FIGS. 1 to 3. FIG.
The present invention can also be applied to an image forming apparatus other than a color laser printer, such as a copier, a facsimile machine, or a multifunction machine having two or three functions of a copier, a facsimile machine, and a printer. Further, the image forming method is not limited to the electrophotographic method, and can be applied to image forming apparatuses such as an inkjet method and a stencil printing method. Also, the present invention can be applied to an image reading apparatus that does not have an image forming apparatus. In addition, the present invention can be applied to any device other than an image forming device and an image reading device as long as the device includes a driving device for driving an object to be driven.

FIG. 1 is a schematic configuration diagram of a printer 500 according to this embodiment.
The printer 500 includes an image forming section 200 and a paper feeding section 300 arranged therebelow. Inside the printer 500, there are four image forming units 1 (1Y , 1M, 1C, 1Bk). The imaging units 1 (1Y, 1M, 1C, 1Bk) each include drum-shaped photoreceptors 2 (2Y, 2M, 2C, 2Bk), and the four photoreceptors 2 (2Y, 2M, 2C, 2Bk) are: They are arranged in parallel in the image forming section 200 at equal intervals in the horizontal direction of the drawing. Each photoreceptor 2 (2Y, 2M, 2C, 2Bk) rotates in the direction of the arrow when the printer 500 operates, due to the drive transmitted from the drive source.

Around each photosensitive member 2 (2Y, 2M, 2C, 2Bk), members and devices necessary for electrophotographic image formation, such as a developing device, are arranged. , 1Bk). In the description of this embodiment, in order to correspond to the toner colors of the image to be formed, Y (yellow), C (cyan), and M representing the colors are added after the numbers indicating the constituent members of each image forming unit 1 for convenience. (magenta) and Bk (black) are added as subscripts. These subscripts may be omitted, especially in the general description.

In the printer 500, all of the four image forming units 1 (1Y, 1M, 1C, 1Bk) have substantially the same configuration, except that the colors of the toners used are different.

FIG. 2 is a schematic explanatory diagram of the image forming unit 1Y for yellow among the four image forming units 1 (1Y, 1M, 1C, 1Bk).
As shown in FIG. 2, in the image forming section 1Y, image forming members such as a charging device 4Y, a developing device 5Y, and a cleaning device 3Y are arranged in order around a photoreceptor 2Y in accordance with an electrostatic photography process. The charging device 4Y includes a charging roller 4aY facing the photosensitive member 2Y, and the developing device 5Y includes a developing roller 5aY, a developing blade 5bY, a screw 5cY, and the like. The cleaning device 3Y also includes a cleaning brush 3aY, a cleaning blade 3bY, a recovery screw 3cY, and the like.

As the photoreceptor 2Y, for example, one having a layered structure in which an organic semiconductor layer, which is a photoconductive material, is provided on the surface of an aluminum cylinder having a diameter of about 30 to 120 [mm] can be used. It is also possible to use a belt-like photoreceptor.

As shown in FIG. 1, below the photoreceptors 2 (2Y, 2C, 2M, 2Bk), a laser beam 8 corresponding to image data of each color is projected onto each photoreceptor 2 which has been uniformly charged by each charging device 4. An exposure device 80 is provided as latent image forming means for scanning the surface and forming an electrostatic latent image. A long and narrow space is secured between each charging device 4 and each developing device 5 in the direction of the rotation axis of the photoreceptor 2 so that the laser beam 8 emitted by the exposure device 80 enters toward the photoreceptor 2 . ing.

The exposure device 80 shown in FIG. 1 is a laser scanning type exposure device using a laser light source, a polygon mirror, etc., and laser light 8 (8Y, 8C) modulated according to image data to be formed from four semiconductor lasers. , 8M, 8Bk). The exposure device 80 houses optical components and control components in a housing made of metal or resin, and has a translucent dust-proof member at the exit port on the top surface. Although the printer 500 shown in FIG. 1 is composed of one housing, a plurality of exposure devices can be individually provided in each image forming section. In addition to an exposure device that uses laser light, an exposure device that combines a known LED array and imaging means can also be used.

Yellow (Y), cyan (C), magenta (M), and black (Bk) toners are detected by toner detection means when consumed by developing devices 5 (5Y, 5C, 5M, and 5Bk) that handle each color. be done. The four toner cartridges 40 (40Y, 40C, 40M, 40Bk) storing toner of each color provided on the top of the printer 500 are supplied to the respective developing devices 5 by the toner replenishing means.

The outer shell of each toner cartridge 40 is a container made of resin, paper, or the like, and has a discharge port in a part thereof so that it can be easily attached to and detached from the mounting portion 400 of the printer 500 . When mounted, this discharge port is coupled with a separate toner replenishing means provided in the printer 500 main body. In addition, in the printer 500, in order to prevent toner from being replenished to a developing device handling a different color due to incorrect installation of the toner cartridge 40 of each color, the mounting portion 400 and the toner cartridge 40 are designed to match each other in shape. Attachment prevention means are provided.

As representatively shown in the image forming section 1Y for yellow in FIG. 2, the developing device 5 is provided with two screws 5cY for agitating and conveying toner and carrier. When the developing device 5Y is attached to the printer 500, one end of the toner replenishing means is connected to the upper portion of the left screw 5cY in FIG. The screw 5cY supplies the toner to the developing roller 5aY rotating in the direction of the arrow, but the developing blade 5bY regulates the thickness of the toner layer on the surface of the developing roller 5aY to a predetermined thickness.

The developing roller 5aY is a cylinder made of stainless steel or aluminum, and is rotatably supported by the frame of the developing device 5Y so as to ensure a regular distance from the photoreceptor 2Y. It has a magnet like so. The electrostatic latent image for each color formed on the surface of each photoreceptor 2 by the laser beam 8 is developed by the developing device 5 handling toner of a predetermined color, and becomes a visible image.

An intermediate transfer unit 6 is provided above the photoconductors 2 (2Y, 2C, 2M, 2Bk). It has an intermediate transfer belt 6a as an image bearing member stretched over a plurality of rollers 6b, 6c, 6d, and 6e, and the intermediate transfer belt 6a moves in the direction of the arrow by rotating the roller 6b to which drive is transmitted by a drive source. run. The intermediate transfer belt 6a is endless, and is stretched so that the surface of each photoreceptor 2 after passing through the portion facing the developing device 5 is in contact with the surface thereof. Four primary transfer rollers 7 (7Y, 7C, 7M, 7Bk) are provided on the inner circumference of the belt so as to face each photosensitive member 2. As shown in FIG.

A belt cleaning device 6h is provided on the outer peripheral portion of the intermediate transfer belt 6a at a position facing the cleaning facing roller 6e. This belt cleaning device 6h wipes away unnecessary toner remaining on the surface of the intermediate transfer belt 6a and foreign matter such as paper dust. A cleaning facing roller 6e facing the belt cleaning device 6h has a mechanism for applying tension to the intermediate transfer belt 6a. The belt cleaning device 6h, which faces the cleaning facing roller 6e with the intermediate transfer belt 6a interposed therebetween, can also move in conjunction with the movement of the cleaning facing roller 6e to ensure proper belt tension.

As the intermediate transfer belt 6a, for example, a belt having a substrate made of a resin film or rubber having a substrate thickness of 50 to 600 [μm] is suitable. The belt has a resistance value that enables the toner image carried by each photosensitive member 2 to be electrostatically transferred onto the belt surface by applying a bias to each primary transfer roller 7 . Each member related to the intermediate transfer belt 6a provided in the printer 500 is integrally supported with the intermediate transfer belt 6a to form an intermediate transfer unit 6, which can be attached to and detached from the printer 500. FIG.

As an example of the intermediate transfer belt, the intermediate transfer belt 6a is made by dispersing carbon in polyamide and adjusting its volume resistance value to about 10 ⁶ to 10 ¹² [Ωcm]. In addition, the intermediate transfer belt 6a is provided with a belt deviation stopping rib for stabilizing the running of the belt on one side or both side ends of the belt.

As an example of a primary transfer roller, the primary transfer roller 7 of the printer 500 is a metal roller whose surface is covered with a conductive rubber material, and a bias is applied to the core from a power supply. The conductive rubber material has carbon dispersed in urethane rubber, and the volume resistance is adjusted to about 10 ⁵ [Ωcm]. A metal roller without a rubber layer can also be used as the primary transfer roller. A secondary transfer roller 14a is provided on the outer periphery of the intermediate transfer belt 6a at a position opposed to the secondary transfer opposing roller 6b as a support roller with the intermediate transfer belt 6a interposed therebetween. The secondary transfer roller 14a is a metal roller whose surface is coated with conductive rubber, and a bias is applied to the core from a power supply 14b. Carbon is dispersed in the conductive rubber, and the volume resistance is adjusted to about 10 ⁷ [Ωcm].

The secondary transfer roller 14a contacts the intermediate transfer belt 6a at a position facing the secondary transfer counter roller 6b, forming a secondary transfer nip as a secondary transfer portion. In the secondary transfer nip, a toner image carried by the intermediate transfer belt 6a is transferred by applying a bias while passing the transfer paper S (paper) as a recording medium between the intermediate transfer belt 6a and the secondary transfer roller 14a. It is electrostatically transferred to the transfer paper S.

A plurality of stages, for example, two stages of paper feed cassettes 9A and 9B are arranged in a drawable manner in a paper feed section 300 below the exposure device 80 . The transfer sheets S stored in these paper feed cassettes are selectively sent out by the rotation of the corresponding call rollers 10A and 10B, and sent to the paper feed path P1 by separation rollers 11A and 11B and transport roller pairs 12A and 12B. Sent.

A timing roller pair 13 consisting of a pair of rollers is provided in the paper feed path P1 in order to determine the timing of feeding the transfer paper S to the secondary transfer portion. The transfer sheet S is conveyed from the timing roller pair 13 toward the secondary transfer nip formed by the intermediate transfer belt 6a and the secondary transfer roller 14a.

The printer 500 has a manual feed tray 25 as a manual feed unit on the right side in FIG. can be stored in The uppermost transfer sheet S stored in the manual feed tray 25 is fed by the manual feed call roller 26 . Then, the sheet is separated by a reverse roller 27 as a separating means so that only one sheet is reliably conveyed, and is sent to a timing roller pair 13 through a sheet feeding path P1 by a pair of conveying rollers 22 and 24 .

A fixing device 15 having a heating means is provided above the secondary transfer nip. The fixing device 15 provided in the printer 500 is composed of a fixing roller 15a having a built-in heater and a pressure roller 15b that abuts on the fixing roller 15a while pressurizing it. The fixing device is not limited to such a configuration, and may be of a type that employs a belt, or that employs an IH as a heating method, as appropriate.

The switching guide 63 is rotatable, and when it is in the state shown in the drawing, the transfer sheet S on which fixing has been completed is guided to the guide member 61a forming the sheet ejection path. The transfer sheet S guided by the guide member 61a is discharged by the rotation of the discharge roller 62 as indicated by arrow D in FIG.

The printer 500 in FIG. 1 has a double-sided unit equipped with a re-feed path and rollers for reversing and re-feeding the transfer paper S so that images can be automatically formed on both sides of the transfer paper S. are doing. Specifically, a switchback path P5 and a paper re-feeding path P6 are provided inside the side frame F, and a switching guide 63, a switching guide 63, and a switching guide 63 are provided to convey the transfer paper S on which image formation has been completed on one side thereof to the paper feeding path P1. It has a second switching guide G2 and a third switching guide G3.

It also has a reversing roller 18a, a reversing roller 22, etc., which are connected to a drive source and can be reversed (forward and reverse rotation) by controlling the drive source. Rollers 23 and 24 are in contact with the reversing roller 22 . When the reversing roller 22 rotates clockwise, it cooperates with the roller 24 to convey the sheet from the manual feed tray 25 . When it rotates counterclockwise, it cooperates with the roller 23 to re-feed the transfer sheet S in the re-feed path P6 toward the timing roller pair 13 .

When the switching guide 63 rotates clockwise from the illustrated state, the transfer sheet S on which fixing has been completed is guided to the reversing transport path P4 by the roller pair 17 and transported to the reversing roller pair 18 via the second switching guide G2. and once sent to the switchback path P5. After the transfer sheet S is sent to the switchback path P5, the reversing roller 18a of the reversing roller pair 18 rotates counterclockwise, and the second switching guide G2 rotates counterclockwise. is sent from the switchback path P5 to the re-feed path P6. In the re-feeding path P6, the transfer paper S conveyed by the roller pairs 15c and 20 and the roller pairs 14c and 21 is further conveyed to the roller pairs 22 and 23 and reaches the timing roller pair 13. FIG.

The printer 500 shown in FIG. 1 includes a paper feeder 50 as an additional paper feeder below the paper feeder 300 . The paper feeder 50 shown in FIG. 1 is provided with two paper feed cassettes 9C and 9D, but a type with a larger number of paper feed cassettes can also be adopted, and even a type with built-in paper feed cassettes with a large number of paper storage can be used. good.

In the printer 500, the third switching guide G3 located above the fixing device 15 and downstream of the roller pair 17 in the conveying direction rotates counterclockwise from the state shown in FIG. It can be conveyed to the paper discharge path P3 and discharged to another paper discharge device. This other paper ejection device is, for example, a bin tray having several stages of paper ejection trays.

Next, the operation of the printer 500 at the time of single-sided printing in which an image is formed on one side of the transfer paper S will be described.
First, the surface of the photoreceptor 2Y uniformly charged by the charging roller 4aY is irradiated with the laser light 8Y corresponding to the image data for yellow emitted from the semiconductor laser by the operation of the exposure device 80, thereby forming an electrostatic latent image. is formed. This electrostatic latent image is developed by a developing roller 5aY and is developed with yellow toner to become a visible image. primary transfer. Such latent image formation, development, and primary transfer operations are sequentially performed in the same manner on the other photoreceptors 2 (2C, 2M, and 2Bk) with appropriate timing.

As a result, the toner images of yellow Y, cyan C, magenta M, and black Bk are carried on the surface of the intermediate transfer belt 6a as four-color toner images that are sequentially overlapped, and the intermediate transfer belt 6a moves on the surface in the direction of the arrow. It is conveyed together with the transfer belt 6a. On the other hand, the surface of the photoreceptor 2 that has passed the position facing the primary transfer roller 7 with the intermediate transfer belt 6a interposed therebetween is cleaned of residual toner and foreign matter by the cleaning device 3 .

The four-color toner image formed on the intermediate transfer belt 6a is transferred onto the transfer paper S conveyed in synchronism with the intermediate transfer belt 6a by the transfer action of the secondary transfer roller 14a. The surface of the intermediate transfer belt 6a is cleaned by the belt cleaning device 6h to prepare for the next image forming/transferring process. The transfer paper S on which the image has been transferred is subjected to a fixing action by the fixing device 15, and is discharged to the paper discharge tray 60 by the paper discharge rollers 62 with the image surface facing downward (face down).

Next, the operation of the printer 500 during double-sided printing in which images are formed on both sides of the transfer paper S will be described.
The transfer sheet S having the image transferred from the intermediate transfer belt 6 a to its one side and passing through the fixing device 15 is guided toward the roller pair 17 by the switching guide 63 in the same manner as in single-sided printing described above. The transfer paper S, which passes through the third switching guide G3 provided on the downstream side of the roller pair 17 in the transport direction and the reversing transport path P4 and advances above the second switching guide G2 at the rotating position in FIG. 18 to the switchback path P5.

At this time, the reversing roller 18a is rotationally driven clockwise. The roller pair 19 in the switchback path P5 is also a pair of rollers that can rotate forward and reverse, and after receiving the transfer sheet S once in the switchback path P5, it is reversed to feed the transfer sheet S in the reverse direction. When the rotation directions of the roller pair 19 and the reversing roller pair 18 are reversed, the second switching guide G2 rotates counterclockwise from the posture shown in FIG.

Then, until the transfer sheet S enters the switchback path P5, the trailing edge of the transfer sheet S is taken as the front edge, and the transfer sheet S is conveyed through the re-feed path P6 by the roller pairs 15c and 20 and the roller pairs 14c and 21 toward the paper feed path P1. to reach the timing roller pair 13 . After that, the timing roller pair 13 takes timing to convey the transfer sheet S having an image on one side thereof again toward the secondary transfer nip where the secondary transfer roller 14a and the intermediate transfer belt 6a face each other, The toner image on the intermediate transfer belt 6a is transferred to the other side of the transfer paper S. As shown in FIG.

The images to be formed on the second surface of the transfer sheet S are sequentially formed by an image forming process that is started when the transfer sheet S is conveyed to a predetermined position. The image forming process in this case is also the same as the above-described full-color toner image formation during single-sided printing, and this full-color toner image is carried on the intermediate transfer belt 6a. However, since the transfer paper S is reversed in the transport path, the image data emitted from the exposure device 80 is created so that the image is formed in the reverse direction in the paper transport direction from the time when the image was first formed. is controlled and executed.

The transfer paper S having the full-color toner images transferred on both sides in this manner is again subjected to fixing processing by the fixing device 15 and discharged onto the paper discharge tray 60 by the paper discharge rollers 62 . In the printer 500, several sheets of the transfer paper S can be transported on the transport path at the same time in order to improve the efficiency of double-sided image formation. Further, the formation timing of the images to be formed on the front and back sides of the transfer sheet S is determined by the control means.

In the printer 500, the polarity of the toner image formed on the photoreceptor 2 is negative, and the toner image on the photoreceptor 2 is transferred to the surface of the intermediate transfer belt 6a by applying a positive charge to the primary transfer roller 7. be done. Further, the toner image on the surface of the intermediate transfer belt 6a is transferred to the transfer paper S by applying a positive charge to the secondary transfer roller 14a.

In addition, regarding these single-sided printing and double-sided printing operations, an example of executing full-color printing has been described. Not only are the unused photoreceptors 2 (2Y, 2M, 2C) and the developing devices 5 (5Y, 5M, 5C) not operated, but the unused photoreceptors 2 (2Y, 2M, 2C) and the intermediate transfer belt 6a are not operated. is equipped with a mechanism to keep the In the printer 500, an internal frame 6f that supports the roller 6d and the primary transfer rollers 7Y, 7C and 7M is rotatably supported around a frame shaft 6g.

During monochrome printing, by rotating the inner frame 6f in a direction away from the photoreceptors 2 (2Y, 2M, 2C) (clockwise in FIG. 1), only the photoreceptors 2Bk come into contact with the intermediate transfer belt 6a. By executing the image process, a monochrome image is created with black toner. In this way, the photoreceptors 2 (2Y, 2M, 2C) of the imaging unit 1 (1Y, 1M, 1C) that are not used during monochrome printing are separated from the intermediate transfer belt 6a, and the photoreceptors 2 (2Y, 2M, 2C) are And stopping the developing devices 5 (5Y, 5M, 5C) is advantageous in terms of extending the life of the image forming sections 1 (1Y, 1M, 1C).

In the printer 500, when the need for maintenance or replacement of parts arises, the exterior cover or the like is opened and maintenance is performed. For this maintenance, it is easier to replace the process cartridge as a unit in which each member constituting the image forming section 1 shown in FIG. 1 is integrally supported.

Further, when the image forming unit 1 shown in FIG. 1 is configured as a process cartridge, a guide portion and a handle for mounting to the printer 500 are provided to facilitate attachment and detachment. If a storage device (for example, an IC tag) for storing the characteristics and operating conditions of the process cartridge is provided, it will serve as a guideline for maintenance and enhance convenience in maintenance management of the process cartridge.

Further, when maintenance or replacement of the intermediate transfer unit 6 is performed, the intermediate transfer belt 6a and each photoreceptor 2 may be separated from each other, and the intermediate transfer unit 6 may be pulled out from the main body of the printer 500. FIG.

FIG. 3 is an explanatory diagram of the vicinity of the side frame F when the side frame F is released from the printer 500 in the state of FIG. The side frame F includes the double-sided unit 30 and the secondary transfer unit 14, and is rotatable with respect to the printer 500 around the lower rotating shaft Fa. When the frame F is rotated, the upper part can be opened as shown in FIG.

In addition, on the upper surface of the side frame F, an engaging projection 71 is provided as a member to be engaged. When the side frame F is moved in the closing direction in order to attach the secondary transfer unit 14 and the duplex unit 30 to the printer 500, the engagement protrusion 71 is the engagement portion of the retracting device 70 provided on the top of the printer 500. engage with. When the engaging protrusion 71, which is the engaged member of the side frame F, engages with the engaging portion of the drawing device 70, the drawing device 70 draws the side frame F toward the printer 500 side.

As the frame is retracted by the retracting device 70 , the guide portion 31 a of the stopper member 31 contacts the blocking member 32 . Then, the stopper member 31 is rotated by the drawing force of the drawing device 70 and overcomes the blocking member 32, the side frame F is closed, and the secondary transfer unit 14 and the duplex unit 30 are mounted at the mounting position.

Prior to the opening of the side frame F, the lock lever is operated to rotate the stopper member 31 provided on the side frame F, thereby removing the stopper member 31 from the blocking member 32 provided on the printer 500 side, thereby releasing the stopper. Unlock and open the function. As shown in FIG. 3, a plurality of transport paths (P1, P2, P6) can be opened by opening the side frame F, so that jammed transfer paper S generated in these transport paths can be easily treated. can.

The secondary transfer unit 14 having the post-transfer transport path P2 and the re-feed path P6 formed on both sides has the center of the roller 23 as the center of rotation, and when the side frame F is opened as shown in FIG. The next transfer roller 14a separates from the intermediate transfer belt 6a. Further, the secondary transfer unit 14 is given a turning habit so that the roller 14c is separated from the roller 21. FIG. The secondary transfer unit 14 is a unit having a power supply 14b inside and a transfer sheet S transport function outside the case.

The fixing device 15 also has a conveying roller 15c and a guide surface for conveying, and a part thereof constitutes a paper re-feeding path P6. In the state shown in FIG. 3, the fixing device 15 is supported so as to be able to be pulled out on the right side of the drawing. Therefore, it is possible to easily deal with a paper jam that has occurred inside the fixing device 15 .

The conveying roller 15c is biased toward the roller 20 by a spring, and the conveying roller 14c is biased toward the roller 21 by a spring. Further, the rollers of the transport roller pair 12A, 12B on the printer 500 side are biased toward the rollers 12Aa, 12Ba on the side frame F side of the transport roller pair 12A, 12B by springs.

As a result, when the side frame F is at the closed position in FIG. 1, the side frame F is opened by the rollers of the transport roller 15c, the transport roller 14c, and the pair of transport rollers 12A and 12B on the printer 500 side. energized. As a result, the stopper surface 31b of the stopper member 31 abuts against the blocking member 32, and the side frame F is positioned.

Next, a paper feeding device as a sheet conveying device used in the printer 500 of this embodiment will be described in more detail.
FIG. 4 is a schematic configuration diagram of the sheet feeding device 50 in this embodiment.
FRR paper feeding methods and RF paper feeding methods are generally known as paper feeding methods of paper feeding devices. In the FRR system (Feed and Reverse Roller system), a reverse torque is applied to a separate roller as a separating member in order to feed sheets one by one. The RF method (Roller Friction method) does not apply reverse torque to the separate roller. The sheet feeding device 50 of this embodiment employs the FRR method.

4, reference numeral 51 is a paper feed tray, reference numeral 52 is a paper guide, reference numeral 53 is a bottom plate, reference numeral 54 is a call roller, reference numeral 55 is a feed roller, reference numeral 56 is a separate roller, reference numeral 58 is a grip roller, and reference numeral K1 is a front end. Reference numeral K2 is the paper detection means, reference P is the paper stack, reference P1 is the previous paper, and reference P2 is the next paper.

The FRR system has a feed roller 55 and a separate roller 56 in pressure contact therewith. The feed roller 55 rotates in the feeding direction of the transfer paper S (paper), but the separate roller 56 feeds via a torque limiter. Driving force (reverse torque) is applied in the direction opposite to the direction. Since the FRR method applies reverse torque, the separation performance is higher than that of the RF method. Both methods have the advantage that even if the positional relationship between the position of the leading edge of the paper and the pressure contact portion (feed nip) between the feed roller 55 and the separate roller 56 is rough, the paper separation performance is not affected. For this reason, no extra cost is required for increasing the positional accuracy, and the paper feeding method is suitable for a front-loading type paper feeding tray, which has become mainstream in recent years.

In FRR and RF paper feeders, sheets are typically picked up from a stack of sheets by rotation of a pickup roller 54 geared to a feed roller 55 . The call roller 54 abuts on the uppermost sheet of the sheet bundle P and feeds out the sheet (previous sheet S1) to the downstream side in the transport direction. Then, the fed preceding sheet S1 is fed downstream in the transport direction by the feed roller 55 positioned downstream of the paper feed tray 51 . Even before the trailing edge of the preceding sheet S1 passes the grounding point of the calling roller 54, when the leading edge of the preceding sheet S1 reaches the gripping roller 58 provided further downstream, the calling roller 54 is separated from the surface of the preceding sheet (or not). drive). When the leading edge of the preceding sheet S1 is detected by the sheet detection means K2 located further downstream of the grip roller 58, the call roller 54 is moved to the top of the paper feed tray 51 to feed out the next sheet S2 using this sheet detection as a trigger. It is brought into contact with the surface of the upper sheet (next sheet S2) (or driven again).

On the other hand, the feed roller 55 is stopped before the trailing edge of the preceding sheet S1 passes over the feed nip in order to prevent paper jam. A one-way clutch is connected to the rotation shaft of the feed roller 55, and even if the drive of the feed roller 55 is stopped, the feed roller 55 itself rotates along with the paper conveying direction conveyed by the grip roller 58 (driven rotation). )do. By stopping the drive of the feed roller 55 and rotating the separate roller 56 in the opposite direction, even if the leading edge of the next sheet S2 has reached the feed nip following the trailing edge of the preceding sheet S1, sheet separation can be performed reliably. Paper jams due to inability to control the interval between the preceding sheet S1 and the next sheet S2 do not occur.

The start timing of the next sheet S2 is triggered by the detection of the leading edge of the preceding sheet S1 by the sheet detecting means K2 provided downstream of the grip roller 58 where the behavior of the sheet is stable (the slip rate is reduced). The trigger starts driving the calling roller 54 and the feed roller 55 at a predetermined timing that does not collide with the trailing edge of the preceding sheet S1 and that satisfies a predetermined print productivity.

By the way, in recent copiers and printers, while it is necessary to keep the paper speed low during image formation in order to achieve high image quality and low power consumption, there is also a demand for high print speed (high print productivity). there is For this reason, although the paper speed is kept low, the space between papers in the paper feed unit is set narrow to achieve both high image quality and high print productivity.

The FRR method and the RF method are advantageous in terms of cost as described above and are suitable for the front loading type. However, in the conventional FRR method and RF method, as described above, the detection of the leading edge of the preceding sheet S1 by the leading edge detection means is used as a trigger to feed out the next sheet S2 from the feed tray 51. The paper interval between S2 was relatively wide.

On the other hand, the distance from the front end position of the paper stacking portion of the paper feed tray 51 to the feed nip of the feed roller 55 is the distance between the front wall 1a of the paper feed tray 51, the paper guide 52, and the paper cassette bottom plate 53 when a small amount of paper is loaded. It varies between 15 and 30 [mm] because the front end of the bundle of sheets retreats due to the rise. Therefore, the start position varies greatly depending on whether or not the preceding sheet S1 and the next sheet S2 are brought out due to friction. In other words, when there is a take-out due to friction, the next sheet S2 taken out by friction with the preceding sheet S1 may have already reached the feed roller 55 when the next sheet S2 starts.

The start timing of the next sheet S2 must be determined so late that the sheet taken to the position of the furthest feed roller 55 does not collide with the trailing edge of the preceding sheet S1. In this case, the actual sheet interval between the next sheet S2 starting from the rearmost sheet feed tray 51 and the preceding sheet S1 is at most about 30 [mm] larger than the target sheet interval, and the print speed is increased. It was a factor that hindered the speedup of the system.

In view of such a problem, in the present embodiment, as shown in FIG. 4, a front end detection means K1 for the paper is provided downstream of the feed roller 55, and the speed of the next paper S2 is increased until the front end detection means K1. It is designed to be transported at a transport speed that is

In the paper feeding device 50 of the present embodiment, after the trailing edge of the preceding sheet S1 has passed the leading edge detecting means K1, when the leading edge detecting means K1 detects the leading edge of the next sheet S2, the leading edge of the preceding sheet S1 and the following sheet S2 are detected. It is determined whether or not the minimum sheet interval δ that can be detected by the sheet detecting means K2 is ensured. That is, the sheet interval δ is calculated from the time when the leading edge of the preceding sheet S1 is detected by the sheet detecting means K2, the length of the sheet, and the time when the leading edge of the next sheet S2 is detected by the leading edge detecting means K1. Then, the conveying state of the feed roller 55 is controlled so that the minimum sheet interval .delta. Further, when the leading edge of the next sheet S2 is detected by the leading edge detecting means K1, if the leading edge of the preceding sheet S1 has not reached the sheet detecting means K2, the transport of the next sheet S2 is temporarily stopped to determine the start position of the next sheet S2. I was like

However, once the feeding of the next sheet S2 is stopped, time loss occurs due to this stop. In order to make up for this time loss, a considerable increase in speed is required when the feeding is resumed thereafter, and in order to cope with this increase in speed, a considerably large stepping motor is required for both the feed roller 55 and the grip roller 58, which causes an increase in cost. was

In this embodiment, two motors for driving the feed rollers 55 are provided, and by adopting a configuration in which the two motors drive the feed rollers 55 that are the same driving target, an increase in size and cost is suppressed.

FIG. 5 is an explanatory diagram showing the driving device 100 that drives the feed roller 55, which is a sheet conveying member.
In this embodiment, an example in which two motors are used to drive the same object will be described, but three or more motors may be used to drive the same object. Also, the plurality of motors for the same driven object may have different motor capacities, types, and the like.

As shown in FIG. 5, the drive device 100 includes two motors, a first motor 101 and a second motor 102, as drive sources. A first gear 105 press-fitted onto the motor shaft 101a of the first motor 101 meshes with the output gear 107, and a second gear having the same shape as the first gear 105 press-fitted onto the motor shaft 102a of the second motor 102. 106 meshes with the output gear 107 . The first gear 105 and the second gear 106 are meshed with an output gear 107 having a large number of teeth provided on the shaft 108 of the feed roller 55, which is the same drive target.

The driving force of the first motor 101 is reduced in rotational motion by the first gear 105 and the output gear 107 and transmitted to the shaft 108 of the feed roller 55 . The driving force of the second motor 102 is reduced in rotational motion by the second gear 106 and the output gear 107 and transmitted to the shaft 108 of the feed roller 55 . As a result, the feed roller 55 is rotated by the driving force of the first motor 101 and the second motor 102 . By driving the feed roller 55 using two motors in this manner, a large driving torque can be generated, and it is possible to cope with an increase in speed. In addition, compared to the case where one high-output motor is used to increase the speed, it is possible to increase the speed at a lower cost.

An encoder 103 for detecting the shaft angle of the motor shaft 101a is attached coaxially with the motor shaft 101a of the first motor 101. As shown in FIG. The shaft angle information detected by the encoder 103 is transmitted to the drive control device 90 that drives and controls the first motor 101 and the second motor 102 . The drive control device 90 performs drive control of the two motors 101 and 102 without interference between the torques of the two motors by performing feedback control using the output information of the encoder 103 . Incidentally, the means for detecting the shaft angle is not limited to the encoder, and any means that can detect the shaft angle of the motor, such as a potentiometer, may be used.

FIG. 6 is a block diagram showing an example of a conventional drive control device 90X.
The conventional drive control device 90X has a first control section 91aX that controls driving of the first motor 101 and a second control section 91bX that controls driving of the second motor 102 . Each control unit performs PID control, which is a type of feedback control.

The first control unit 91aX feeds back the position signal x1det and the angular velocity v1det from the encoder 103 that detects the shaft angle of the motor shaft 101a of the first motor 101, and obtains the deviation between the position target value xtgt and the angular velocity vtgt. Then, a current value or a voltage value as a drive control signal for driving the first motor 101 is output based on the deviation. The second control unit 91bX feeds back the position signal x2det and the angular velocity v2det from the encoder 104 that detects the shaft angle of the motor shaft 102a of the second motor 102, and obtains the deviation between the position target value xtgt and the angular velocity vtgt. Then, based on the deviation, a current value or voltage value is output as a drive control signal for driving the second motor 102 .

However, the conventional drive control device 90X shown in FIG. 6 is provided with a control unit that performs PID control for each motor. It is possible to perform a backlash correction operation by slightly offsetting. However, on the other hand, it is necessary to provide a means for detecting the shaft angle such as an encoder for performing PID control for each motor, and a control circuit and control board for performing PID control. may lead to an increase in size. In addition, there is a drawback that the hardware configuration and control method become complicated.

Therefore, in the present embodiment, one PID control section drives and controls a plurality of motors with the same drive control signal (voltage value or current value). As a result, drive control can be performed based on a signal from a common encoder for a plurality of drive sources, and the control circuit and control board for performing PID control can be integrated into one. cost reduction can be achieved. Therefore, it can be suitably used for a device in which cost and downsizing of the device are prioritized over functionality.

Here, in controlling the two motors 101 and 102 that drive the feed roller 55, which is the same object to be driven, conventionally, only one of these motors 101 and 102 is operated for reasons other than motor failure. There is no control for driving the feed roller 55 with .

However, the driving load applied to the feed roller 55 or the driving torque required to drive the feed roller 55 depends on the type of paper (thickness, surface roughness, etc.) that is the object to be conveyed by the feed roller 55 and the required It differs depending on the difference in paper transport speed and the like. For example, when transporting a thin type of paper or transporting paper at a low transport speed, the driving torque required to drive the feed roller 55 is small, and the driving force of only one motor is sufficient. In some cases, the feed roller 55 can be driven at the same time. In such a case, if only one motor is used for driving, energy can be saved by not driving the other motor, and the life of the other motor can be extended.

Therefore, in this embodiment, even when the two motors 101 and 102 can drive the feed roller 55, which is the same object to be driven (neither of the motors is out of order), these motors are Only one motor out of 101 and 102 can be driven.

FIG. 7 is a block diagram showing an example of the drive control device 90' of this embodiment.
The drive control device 90' of the example shown in FIG. 7 is different from the conventional drive control device 90X shown in FIG. The position signal x2det and the angular velocity v2det of 102 are not fed back to the second control section 91bX. As a result, the feedback signal is only the position signal x1det from the encoder 103 for detecting the shaft angle of the motor shaft 101a of the first motor 101 and the angular velocity v1det. By performing feedback control with a single feedback signal in this way, torque interference between the two motors 101 and 102 is prevented, and both of the two motors 101 and 102 drive the feed roller 55, which is the same drive target. can do.

As the feedback signal, only the position signal x1det of the first motor 101 may be used as the position signal, and two angular velocities v1det and v2det of the motors 101 and 102 may be used as the speed signals. In this case, the vibration damping performance of the device can be improved, and the control characteristics of the motors 101 and 102 can be adjusted according to the characteristics of the motors 101 and 102 and the required characteristics of the device.

Here, in the conventional drive control device 90X shown in FIG. 6 and the drive control device 90' of the example shown in FIG. For example, it is possible to slightly offset the first motor 101 and the second motor 102 when stopped to perform backlash correction. However, on the other hand, it is necessary to provide a means for detecting the shaft angle such as an encoder for performing PID control for each motor, and a control circuit and control board for performing PID control. may lead to an increase in size. In addition, there is a drawback that the hardware configuration and control method become complicated.

Therefore, in this embodiment, the two motors 101 and 102 are driven and controlled with the same drive control signal (voltage value and current value) by one PID control section. As a result, the two motors 101 and 102 can be driven and controlled based on the signal from the common encoder 103, and the control circuit and control board for performing PID control can be integrated into one. It is possible to reduce the cost of the equipment. Therefore, it can be suitably used for a device in which cost and downsizing of the device are prioritized over functionality.

FIG. 8 is a block diagram of the drive control device 90 of this embodiment.
As shown in FIG. 8, the drive control device 90 of the present embodiment includes a control unit 91 common to the motors 101 and 102 that perform PID control, and a first mode drive that drives both the first motor 101 and the second motor 102. (first drive mode), a second mode (second drive mode) in which only the first motor 101 is driven, and a third mode (second drive mode) in which only the second motor 102 is driven (second drive mode). 92.

The mode switching unit 92 includes a first three-state buffer 94a as signal blocking means arranged on a transmission path of a drive control signal between the control unit 91 and a first pre-driver 95a that drives the first motor 101, and a control A second three-state buffer 94b as a signal blocking means arranged in the transmission path of the drive control signal between the unit 91 and the second pre-driver 95b that drives the second motor 102, and each of the three-state buffers 94a and 94b and a state command section 93 for transmitting a state command signal.

The state command section 93 outputs a state command signal: High/Low to each of the three-state buffers 94a and 94b. Each of the three-state buffers 94a and 94b cuts off the drive control signal transmitted from the control unit 91 when the state command signal: Low is input, and controls when the state command signal: High is input. The drive control signal transmitted from the unit 91 is transmitted to the pre-driver.

The example shown in FIG. 8 shows the state in the first mode in which both the first motor 101 and the second motor 102 are driven. It is

The control unit 91 feeds back the position signal xdet and the angular velocity vdet from the encoder 103 for detecting the shaft angle of the motor shaft 101a, and obtains the deviation between the position target value xtgt and the angular velocity vtgt. Then, based on the deviation, a drive command signal (PWM signal) and a direction command signal (DIR signal) as drive control signals common to each motor are generated and transmitted to the motors 101 and 102 . In this embodiment, a PWM signal is used as the drive command signal, but a current value, a voltage value, or a combination thereof may be used as the drive command signal.

In the first mode, which is set during the normal operation of feeding, the three-state buffers 94a and 94b are supplied with a state command signal of High. Therefore, the drive command signal (PWM) as the drive control signal sent from the controller to the motors 101 and 102 is sent to the pre-drivers 95a and 95b. Thereby, the first motor 101 and the second motor 102 are driven, and the feed roller 55 is driven by both the first motor 101 and the second motor 102 .

Thus, in the first mode, both the first motor 101 and the second motor 102 are driven, so a large driving force and a large driving torque can be obtained. Further, by using a single control unit 91 and providing a single negative feedback, a large driving force can be obtained with a simple and inexpensive configuration.

However, in this embodiment, only a single drive control signal and a single negative feedback are seen, so in the first mode, even if one of the two motors 101 and 102 fails, Failures may not be detected properly.

More specifically, if one of the two motors 101 and 102 fails while the motor is being driven under a high drive load condition, the position signal xdet from the encoder 103 will be significantly delayed due to a decrease in torque. or the drive command signal (current value, etc.) generated by the control unit 91 increases significantly. Therefore, the failure can be detected based on the position signal xdet from the encoder 103 and the drive command signal. However, it is not possible to specify which motor is the faulty motor.

In addition, when one of the two motors 101 and 102 fails while driving in a low drive load state, the position signal xdet from the encoder 103 is not greatly delayed, so the failure of the motor itself can be prevented. cannot be detected.

As described above, in the first mode, there are cases where the failed motor cannot be specified, or the failure of the motor itself cannot be detected. Therefore, in this embodiment, an inspection mode is provided, and the second mode and the third mode are executed to detect failure of the motor.

FIG. 9 is a block diagram of the drive control device 90 when executing the second mode in which only the first motor 101 is driven.
The second mode shown in FIG. 9 is set when the first motor 101 is inspected for failure. At this time, the state command unit 93 inputs the state command signal: High to the first three-state buffer 94a and inputs the state command signal: Low to the second three-state buffer 94b. Thereby, the drive command signal (PWM signal) transmitted from the control section 91 to the first motor 101 is transmitted to the first pre-driver 95a, and the first motor 101 is driven. On the other hand, the second three-state buffer 94b to which the state command signal: Low is input cuts off the drive command signal (PWM signal) from the controller. As a result, the drive command signal (PWM signal) is not input to the second pre-driver 95b, and the second motor 102 is not driven. Thereby, only the first motor 101 is driven.

FIG. 10 is a block diagram of the drive control device 90 when executing the third mode in which only the second motor 102 is driven.
The third mode shown in FIG. 10 is set during failure inspection of the second motor 102 . At this time, the state command unit 93 inputs the state command signal: High to the second three-state buffer 94b, and inputs the second state command signal: Low to the first three-state buffer 94a. Thereby, the drive command signal (PWM signal) transmitted from the control unit 91 to the second motor 102 is transmitted to the second pre-driver 95b, and the second motor 102 is driven. On the other hand, the first three-state buffer 94a to which the state command signal: Low is input cuts off the drive command signal (PWM signal) from the control section. As a result, the drive command signal (PWM signal) is not input to the first pre-driver 95a, and the first motor 101 is not driven. Thereby, only the second motor 102 is driven.

In the inspection mode of the present embodiment, first, the second mode is executed for a specified period of time to detect whether or not the first motor 101 is faulty. At this time, the control unit 91 monitors whether the output of the encoder 103 is abnormal. When the controller 91 determines that the output of the encoder is abnormal, it determines that the first motor 101 is out of order.

On the other hand, if it is determined that there is no abnormality in the first motor 101, the third mode is executed for a specified period of time to detect whether or not the second motor 102 has failed. When it is determined that the output of the encoder 103 is abnormal, it is determined that the second motor 102 is out of order.

In this embodiment, the failure inspection of the second motor 102 is performed after performing the failure inspection of the first motor 101, but the failure inspection of the first motor 101 is performed after performing the failure inspection of the second motor 102. you can go

Further, motor failure can be determined by monitoring drive command signals such as drive current values and PWM values generated by the control unit 91 and comparing them with normal operation or with a predetermined threshold to determine motor failure. good.

Such an inspection mode may be performed during an initializing operation as an initial operation performed when the apparatus is powered on or when returning from a standby state. Also, the inspection mode may be executed at the end of paper feeding. By executing the inspection mode only at the end of paper feeding without executing the inspection mode during the initialization operation, it is possible to shorten the preparation period at the time of start-up.

Also, the inspection mode may be executed when the feed roller 55 is temporarily stopped during paper feeding. When the inspection mode is executed while the feed roller 55 is temporarily stopped, the direction command signal (DIR) transmitted by the control unit 91 is set in the opposite direction to the feeding direction (rotational driving direction during normal operation). A direction command signal (DIR) for rotational driving is used. As a result, in the inspection mode, the first motor 101 and the second motor 102 are rotationally driven in the direction opposite to that during feeding. Since the one-way clutch is connected to the rotating shaft 108 of the feed roller 55 as described above, the driving force of the motor is not transmitted to the feed roller 55 when the motors 101 and 102 are reversely driven. As a result, even if the inspection mode is executed with the paper sandwiched between the feed roller 55 and the separate roller 56, the paper will not be transported and the feeding will not be affected. Further, by executing the inspection mode when the feed roller 55 is temporarily stopped, it is possible to frequently inspect the failure of the motor.

Further, the feed roller 55 is configured to be able to come into contact with and separate from the separate roller 56, and when the inspection mode is executed when the feed roller 55 is temporarily stopped during paper feeding, the feed roller is moved with respect to the separate roller 56. The inspection mode may be executed by separating them. With such a configuration as well, the motor can be inspected without affecting the paper sandwiched between the feed roller 55 and the separate roller 56 .

In the inspection mode, the second mode and the third mode are executed to inspect the operation of both the first motor 101 and the second motor 102, but only one of the motors is inspected. good too. In this case, when the first motor 101 is inspected for operation, the second motor 102 is inspected for operation in the next inspection mode. .

Also, a three-state buffer, which is a simple integrated circuit, can be used to switch between a first mode in which all motors are driven, a second mode in which only the first motor 101 is driven, and a third mode in which only the second motor 102 is driven. can be done. As a result, it is possible to provide a driving device capable of switching operation modes with a simple and inexpensive configuration.

In addition, in the present embodiment, a three-state buffer is arranged in each drive command signal transmission line between the control unit and each drive source to switch between blocking and transmission of the drive command signal from the control unit. It is not limited to this. For example, a switch may be provided in place of the three-state buffer, and the blocking/transmission of the drive command signal may be switched by switching ON/OFF of the switch. The ON/OFF of the switch may be manually performed by the user, or may be performed under the control of the device.

Further, in the present embodiment, the encoder 103 detects the shaft angle of the motor shaft 101a of the first motor 101, but is not limited to this. For example, it detects the shaft angle of the motor shaft 102a of the second motor 102. Alternatively, the shaft angle of the shaft 108 of the feed roller 55 may be detected.

Also, the encoder 103 may be built in the motor, or may generate the position signal xdet and the angular velocity vdet using the internal signals of the motor and feed them back to the control section 91 . Further, encoders are provided in both the first motor 101 and the second motor 102, and the position signals xdet and the angular velocities vdet of a plurality of encoders are selectively fed back to the control unit 91 after performing calculation such as averaging processing. good too. In this way, when an encoder is provided for each motor, it leads to an increase in the cost of the device compared to the above-described one in which each motor is provided with one common encoder. However, since the control unit that generates and transmits drive control signals and detects failures is a common control unit for each motor, compared to the conventional technology in which a control unit is provided for each motor, the cost is low and the device is compact. can be improved.

FIG. 11 is a flow chart showing an example of the mode selection procedure in this embodiment.
First, the drive control device 90 performs the above-described motor failure inspection to determine whether there is a failed motor (S1). If there is a failed motor (Yes in S1), the drive control device 90 sends motor failure information including the fact that a motor failure has occurred from the communication network to the customer service management device via the control section of the printer main body. Notify (S2).

After that, the drive control device 90 further determines whether or not all the motors 101 and 102 are out of order (S3). Since the roller 55 cannot be driven, the user is notified (reported) that maintenance or motor replacement is required, and the controller of the printer body is notified to stop the system (S4).

On the other hand, if only some of the motors have failed (No in S3), it is possible to drive the feed roller 55 only with some of the motors that have not failed. Therefore, when the first motor 101 fails, the third mode using only the second motor 102 is selected, and when the second motor 102 fails, the second mode using only the first motor 101 is selected. is selected and operated (S6).

At this time, the paper type information and transport speed settings that can be selected are limited to those that can be operated by only one motor. The user is notified on the touch panel through the control section of the printer main body (S5). However, if the sheet type information has already been selected to be operable by one motor, and only the conveying speed is switched to one that is operable by one motor, it becomes possible to operate by one motor. In such a state, only the conveying speed may be automatically switched to execute the operation (second mode or third mode) with one motor without notifying the user at all. In this case, it is possible to continue using the system without making the user feel the failure as much as possible.

On the other hand, if there is no malfunctioning motor (No in S1), the drive control device 90 determines whether the paper type information and transport speed settings selected by the user can operate with only one motor through the control unit of the printer main body. It is determined whether or not (S7, S8). That is, in this determination, the first condition that the driving load applied to the feed rollers 55, which are the same driven target, is greater than or equal to the predetermined value, or the driving load applied to the same driven target, the feed rollers 55, is less than the predetermined value is satisfied. It is determined whether or not the second condition that is is satisfied.

In this determination, for example, the selected paper type information is thin paper, or the transport speed is low speed mode (energy saving mode), and it is possible to operate with only one motor (that is, the second condition is satisfied). (Yes in S7, Yes in S8), the second mode or the third mode in which only one motor drives is selected and executed (S6). For example, if the selected paper type information is thick paper or the transport speed is high speed mode, and it is determined that it is not possible to operate with only one motor (that is, the first condition is satisfied). (No in S7, No in S8), the first mode in which both the two motors 101 and 102 are driven is selected and executed (S9).

Although the flowchart described above is an example assuming the case where the number of motors is two, the same applies when the number of motors is three or more.
Further, it is preferable to determine whether to use the second mode or the third mode when feeding a sheet requiring a low torque for feeding based on the frequency of use of the motor.

In this embodiment, as described above, it is determined whether the first condition or the second condition is satisfied based on the paper type (paper type) and the transport speed, and the first mode, second mode, and third mode are determined. is selected and executed, but it is not limited to this, and it may be determined whether the first condition or the second condition is satisfied based on other information.

For example, when a high-speed mode and a low-speed mode (power saving mode) are provided, in the high-speed mode, the feed roller is set in the first mode in order to perform high-speed feeding control that requires speed-up control of the feed roller as described above. 55 may be driven, and the feed roller 55 may be driven in the second mode or the third mode without performing the high-speed feeding control when in the low speed mode (power saving mode).

Further, for example, in the high-speed feeding control, the feed roller 55 is driven in the first mode only when the speed is increased when the feeding of the next sheet S2 is resumed after the feeding of the next sheet S2 is temporarily stopped. The feed roller 55 may be driven in either the mode or the third mode.

FIG. 12 is a flow chart showing the flow of control during execution of the second mode or third mode in which the feed roller 55 is driven by only one motor.
When the second mode or the third mode (here, the second mode) is selected and executed (S6) in which the feed roller 55 is driven by only one motor, the drive control device 90 It is monitored whether or not the drive amount (here, converted to the paper transport distance) of one of the motors (first motor 101) that is driving the motor exceeds a specified distance (for example, 100 [m]) (S11). Then, when the paper transport distance by one motor (first motor 101) exceeds the specified distance (Yes in S11), one motor (first motor 101) that is being driven is switched to the other motor that is not being driven. In order to switch to the motor (second motor 102), the third mode is selected and executed (S14).

At the time of this switching, the drive control device 90 refers to the failure presence/absence determination result for the other motor (the second motor 102) that is not being driven, and if the other motor (the second motor 102) has not failed ( No in S12), the third mode is selected and executed in order to switch to the other non-driving motor (second motor 102) (S14). If the other motor (second motor 102) fails (Yes in S12), switching to the other non-driven motor (second motor 102) is not performed (S13), and the second mode is performed. is selected, and one of the motors (the first motor 101) being driven continues to be driven.

When the third mode is selected and switched to the other motor (second motor 102) (S14), furthermore, when the paper transport distance of the other motor (second motor 102) after switching exceeds a specified distance (S11 ), this time the second mode is selected and the motor is switched to the original one (first motor 101) (S14).

In this way, by alternately driving the two motors 101 and 102 one by one, one of the two motors 101 and 102 is not overworked, and the two motors 101 and 102 can be operated simultaneously. Drive amount can be leveled. As a result, it is possible to lengthen the period until one of the two motors fails, thereby extending the life of the motor.

In this embodiment, the two motors 101 and 102 are alternately used to equalize the driving amounts of the two motors 101 and 102. There is a possibility that the failure may occur. In such a case, the driving amounts of the two motors 101 and 102 may be made uneven. For example, when driving only one motor, only the second mode of driving the first motor 101 may be selected.

FIG. 13 is an explanatory diagram showing the display contents of the touch panel, which is the printer operation unit, when the user selects paper type information.
When the user displays a paper type selection screen as shown in FIG. 13 on the touch panel, the user can select the paper type to be used from among a plurality of paper types on the paper type selection screen. can. In the example of FIG. 13, paper types that can be driven by only one motor are "my paper" and "thin paper".

FIG. 14 is an explanatory diagram showing the display contents of the touch panel when the user selects the transport speed.
When the user displays a transfer speed setting screen as shown in FIG. 14 on the touch panel, the user can select and determine a desired transfer speed from a plurality of transfer speeds on the transfer speed setting screen. In the example of FIG. 14, the transport speed that can be driven by only one motor is "low speed".

FIG. 15 is an explanatory diagram showing the display contents of the touch panel displayed when notifying the user of motor failure.
The example of FIG. 15 is an example of an image displayed on the touch panel when the first motor 101 (motor 1) of the two motors 101 and 102 that drive the feed roller 55 fails. This display informs the user which motor has failed and prompts the user to perform maintenance and replacement of the motor. In addition, in this display, it is informed that the type of paper that can be used and the transport speed are limited if the printer continues to be used with only one motor that is not malfunctioning, as shown in FIGS. The screen guides you to select a limited paper type and transport speed.

Note that the indication that all the motors 101 and 102 have failed notifies which motor has failed and prompts maintenance and replacement of the motor, but does not indicate whether to continue using the printer.

What has been described above is only an example, and each of the following aspects has a unique effect.
[First aspect]
The first mode includes control means (eg, control section 91, mode switching section, etc.) that controls a plurality of drive sources (eg, two motors 101 and 102) that drive the same driven object (eg, feed roller 55). In the drive control devices 90, 90', the control means drives the same drive target with the plurality of drive sources in a state in which the same drive target can be driven by the plurality of drive sources. selecting a drive mode (e.g., first mode) or a second drive mode (e.g., second mode or third mode) in which the same drive target is driven by some of the plurality of drive sources; It is characterized by executing
According to this aspect, even in a state in which the same drive target can be driven by a plurality of drive sources, the second drive mode in which the same drive target is driven by some of the plurality of drive sources is selected. can be executed. Therefore, when it is not necessary to drive the same object with a plurality of drive sources, by selecting and executing the second drive mode, the drive of the other drive sources can be stopped, thereby saving energy. can be achieved, and the service life of the other drive source can be extended.

[Second aspect]
In a second aspect based on the first aspect, the control means selects the first drive mode when a first condition (e.g. thick paper, high speed mode) is satisfied that the drive load applied to the same drive object is equal to or greater than a predetermined value. The second drive mode is selected when a second condition (for example, thin paper, low speed mode) that the drive load applied to the same drive object is less than the predetermined value is satisfied.
According to this, in a situation where the drive load is large, driving is stabilized by selecting and executing the first drive mode in which the same drive target is driven by a plurality of drive sources, while in a situation where the drive load is small. Then, energy saving can be achieved by selecting and executing the second drive mode in which the object to be driven is driven by only a part of the drive sources.

[Third aspect]
A third aspect is the second aspect, wherein the control means controls the type specifying information (eg, paper type information) of a conveyed object (eg, transfer paper S) conveyed by the same driving target or the driving of the same driving target. It is characterized in that it is determined whether or not the first condition or the second condition is satisfied based on speed information (for example, conveying speed information).
According to this, it is possible to easily determine whether the drive load is large or small.

[Fourth aspect]
A fourth aspect is characterized in that, in any one of the first to third aspects, the control means switches the drive source to be driven according to a predetermined switching condition during execution of the second drive mode. .
According to this, it is possible to prevent a part of the plurality of drive sources from being overworked, thereby preventing the part of the drive sources from having a short life.

[Fifth aspect]
A fifth aspect is characterized in that, in the fourth aspect, the predetermined switching condition is a condition that the driving source for driving is switched for each predetermined driving amount (for example, paper conveying distance).
According to this, it is possible to equalize the usage amounts (driving amounts) of the plurality of driving sources, and to extend the life of the driving device.

[Sixth aspect]
According to a sixth aspect, in any one of the first to fifth aspects, the control means, when one of the plurality of drive sources becomes inoperable (for example, a failure state), It is characterized in that the same drive object is driven by the remaining drive sources.
According to this, downtime can be reduced.

[Seventh aspect]
A seventh aspect is characterized in that, in the sixth aspect, the control means performs notification processing for notifying the user that the driving is impossible.
According to this, the user can be urged to replace or maintain the motor that has become undrivable, and the motor can be recovered quickly.

[Eighth aspect]
An eighth aspect is characterized in that, in the sixth or seventh aspect, the control means performs a notification process for notifying a management device via a communication network that the driving is impossible. It is something to do.
According to this, it is possible to recover more quickly.

[Ninth aspect]
A ninth aspect is a drive device 100 having a plurality of drive sources for driving the same object to be driven, and is characterized by including the drive control device according to any one of the first to eighth aspects.
According to this, in a situation where it is not necessary to drive the same drive target with a plurality of drive sources, the other drive sources can be stopped by selecting and executing the second drive mode. energy saving can be achieved, and the service life of the other drive source can be extended.

[Tenth Aspect]
A tenth aspect is a sheet conveying device (e.g., the sheet feeding device 50), which is characterized by including the driving device of the ninth aspect.
According to this, in a situation where it is not necessary to drive the same drive target with a plurality of drive sources, the other drive sources can be stopped by selecting and executing the second drive mode. Therefore, it is possible to provide a sheet conveying apparatus capable of saving energy and extending the life of the other driving source.

[11th aspect]
An eleventh aspect is an image forming apparatus (for example, the printer 500), which is characterized by including the driving device of the ninth aspect.
According to this, in a situation where it is not necessary to drive the same drive target with a plurality of drive sources, the other drive sources can be stopped by selecting and executing the second drive mode. It is possible to provide an image forming apparatus capable of saving energy and extending the life of the other drive source.

Reference Signs List 1: Imaging unit 2: Photoreceptor 3: Cleaning device 4: Charging device 5: Developing device 6: Intermediate transfer unit 6a: Intermediate transfer belt 7: Primary transfer rollers 9A to 9D: Paper feed cassettes 10A and 10B: Call roller 11A , 11B: separation rollers 12A, 12B: conveying roller pair 14: secondary transfer unit 14a: secondary transfer roller 15: fixing device 30: duplex unit 40: toner cartridge 50: paper feeding device 51: paper feeding tray 52: paper guide 53: Paper cassette bottom plate 54: Call roller 55: Feed roller 56: Separate roller 58: Grip roller 60: Paper discharge tray 80: Exposure device 90, 90': Drive control device 91: Control unit 92: Mode switching unit 93: State Command unit 100 : Drive unit 101 : First motor 102 : Second motors 103 and 104 : Encoder 105 : First gear 106 : Second gear 107 : Output gear 108 : Rotating shaft 200 : Image forming unit 300 : Paper feeding unit 400 : Mounting unit 500 : Printer

JP-A-2006-42483

Claims (7)

a plurality of drive sources for driving the same sheet conveying member ;
A sheet conveying apparatus comprising : a control means for controlling the plurality of drive sources ,
Based on the type specifying information of the sheet conveyed by the same sheet conveying member or the driving speed information of the same sheet conveying member, the control means controls whether the driving load applied to the same sheet conveying member is equal to or greater than a predetermined value. When a certain first condition is satisfied, a first driving mode in which the same sheet conveying member is driven by the plurality of driving sources is selected and executed , and the driving load applied to the same sheet conveying member is less than the predetermined value. A sheet characterized by selecting and executing a second drive mode in which the same sheet conveying member is driven by a part of the plurality of drive sources when the second condition is satisfied. Conveyor. In the sheet conveying device according to claim 1 ,
The sheet conveying apparatus , wherein the control means switches the driving source according to a predetermined switching condition during execution of the second driving mode. In the sheet conveying device according to claim 2 ,
The sheet conveying apparatus , wherein the predetermined switching condition is a condition that the driving source for driving is switched for each predetermined driving amount. The sheet conveying device according to any one of claims 1 to 3 ,
wherein the control means drives the same sheet conveying member with the remaining drive source when any one of the plurality of drive sources becomes inoperable. Conveyor . In the sheet conveying device according to claim 4 ,
The sheet conveying apparatus, wherein the control means performs notification processing for notifying a user that the sheet conveying apparatus is in the undriveable state. In the sheet conveying device according to claim 4 or 5 ,
The sheet conveying apparatus, wherein the control means performs a notification process for notifying a management apparatus via a communication network that the sheet conveying apparatus is in a non-drivable state. An image forming apparatus comprising the sheet conveying device according to claim 1 .

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