JP2004003543A - Driving device for rotated body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize silent and smooth power transmission, obtain high transmission efficiency, and reduce size, weight, and costs. <P>SOLUTION: Two guide rollers 37a, 37b and a movable roller 38 moving when transmitting torque are provided between an outer ring 32 and a high speed side shaft 17. A wedge roller type transmission A is a reduction gear, and a drive shaft 51 of an electric motor 50 is integrally connected with the high speed side shaft 17. A rotated body X is mounted on a low speed side shaft 3. The rotated body X is, for example, photoreceptor drums 141C to 141K, a transfer roller, paper conveyance rollers 162, 167 (paper feeding roller), or a drive roller 132 for a paper conveyance belt. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention is for rotating an object to be rotated (for example, a photosensitive drum, a transfer roller, a paper transport roller, a drive roller for a paper transport belt, etc.) mounted on an image forming apparatus such as a color printer or a color copy, or a printing apparatus. The present invention relates to a driving device for a driven member.
[0002]
[Prior art]
In an image forming apparatus or a printing apparatus such as a color printer or a color copy, a driving device that rotates a photosensitive drum, a transfer roller, a paper transport roller, a drive roller for a paper transport belt, and the like, for example, JP-A-2000-23495, It is disclosed in JP-A-10-198187 or JP-A-8-200621.
[0003]
In these publications, a stepping motor directly connected to the photoconductor drum is used as a drive source for the photoconductor drum, a paper conveyance roller, and the like. Further, as these drive sources, an electric motor to which a gear reducer is connected is also used.
[0004]
[Problems to be solved by the invention]
However, the following problems are encountered in the above-mentioned publications in which a stepping motor is directly connected as a drive source of a photosensitive drum, a paper conveying roller, and the like, and a gear reducer is connected to an electric motor. There are points.
[0005]
For example, a color printer creates an overall color image by printing each color element such as black, yellow, magenta, and cyan one after another. At this time, even if the paper feed is slightly deviated, each color element is deviated on the paper surface, causing color unevenness. In a gear type speed reducer, backlash occurs due to its structure, which causes color unevenness.
[0006]
Further, in the case of a gear type speed reducer, a gear noise may be generated, which may adversely affect the environment around a printing machine or a copying machine. In particular, for home use and office use, even a small noise significantly lowers the commercial value.
[0007]
Further, in the system in which the stepping motors are directly connected, the motor may be rotated at a low rotation speed and a high torque, which results in an increase in the size of the motor, an increase in the complexity of the controller, and an increase in the power supply. In any case, the cost of the entire apparatus is increased and the size is increased.
[0008]
SUMMARY OF THE INVENTION An object of the present invention has been made in view of the above-described circumstances, and enables quiet and smooth power transmission, high transmission efficiency, and reduction in size, weight, and cost. It is an object of the present invention to provide a driven device for a rotating body capable of achieving the following.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a driving device for a rotated body according to claim 1 of the present invention is a driving device for rotating a rotated body mounted on an image forming apparatus or a printing apparatus,
A rotating body is connected to a low-speed side shaft of the traction drive type reduction gear, and a drive shaft of an electric motor is connected to the high-speed side shaft.
[0010]
Further, in the driving device for a driven body according to claim 2, the driven body includes a photosensitive drum, a transfer roller, a paper transport roller, a drive roller for a paper transport belt, a pressure roller, a heat roller, a charging roller, and a feed roller. , A magnet roller, a developing roller, a platen roller, or an impression cylinder.
[0011]
Further, in the driving device for a driven body according to claim 3, the traction drive type speed reducer is rotatably supported by a housing, and has a low-speed side shaft provided with an outer ring at one end, and the low-speed side shaft and the outer ring. A high-speed side shaft eccentrically supported by the housing and rotatably supported by the housing; and at least one guide roller and at least one movable roller rotatably supported between the outer race and the high-speed side shaft. And a friction roller type speed reducer utilizing a wedge action.
[0012]
As described above, according to the present invention, since a traction drive type speed reducer (particularly, a wedge roller type speed reducer) is used, quiet and smooth power transmission can be performed, and high transmission efficiency can be obtained. In addition, size, weight, and cost can be reduced.
[0013]
Further, the traction drive device (wedge roller type speed reducer) is a friction drive and has no backlash, so that the accuracy of paper feeding is improved and defects such as color unevenness are eliminated.
[0014]
Further, since there is no gear engagement, no noise is generated. The noise level generated by the entire apparatus can be suppressed, and the commercial value especially for home use and office use can be enhanced.
[0015]
Further, since there is no need to use a motor in which stepping motors are directly connected, the motor can be downsized, the controller can be simplified, and the power supply can be simplified.
[0016]
Further, unlike the shrink fit type planetary traction speed reducer, the wedge roller type speed reducer has a torque-sensitive pressing force generating mechanism, so that the transmission efficiency is high (98% or more). Therefore, the drive current of the motor can be reduced, and the power consumption of the entire apparatus can be reduced.
[0017]
Further, if a wedge roller type speed reducer having a characteristic of transmitting drive in one direction only (one-way clutch function) is used, for example, even if a motor malfunctions, the paper is not sent in the reverse direction, and It also has aspects of a fail-safe mechanism that can eliminate the possibility of clogging.
[0018]
Further, the wedge roller type speed reducer may have a one-way clutch function that transmits torque during forward rotation, and idles and does not transmit torque during reverse rotation, or the wedge roller type speed reducer may The wedge roller type speed reducer that transmits torque when rotating in both forward and reverse directions may transmit torque when rotating in both forward and reverse directions.
[0019]
The traction drive type transmission has been developed for various industrial uses because of its quietness and smoothness. In recent years, attempts have been made to apply it to personal use such as automobiles and bicycles, and it has attracted attention as a next-generation power transmission system. ing.
[0020]
A traction drive type transmission is different from a gear transmission in that at least two rotating bodies having a smooth surface are strongly pressed and a lubricating oil film (for example, an EHL oil film) is interposed therebetween to transmit power. The basic formula is represented by a simple friction formula of Ft = μ · Fc (Ft: traction force). Here, Fc is called a pressing force, and various methods have been developed for generating the pressing force.
[0021]
As one of the traction drive type transmissions, there is a friction roller type transmission utilizing a wedge action (hereinafter referred to as a wedge roller type transmission). A wedge roller type transmission is an outer ring rotatably provided around an end of a high speed side shaft in an eccentric state with respect to the high speed side shaft, and a drive side cylinder which is an outer peripheral surface of the high speed side shaft. Power transmission between respective outer peripheral surfaces, which are arranged in an annular space that is disposed between the outer peripheral surface and a driven-side cylindrical surface that is an inner peripheral surface of the outer ring and has a radial width that is not uniform in the circumferential direction. A transmission having at least one guide roller and at least one movable roller as a cylindrical surface for use. The movable roller is a roller that generates a pressing force by a wedge action, and is a roller that moves in a radial direction and a circumferential direction.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a driven device for a rotating body including a wedge roller type transmission according to an embodiment of the present invention will be described with reference to the drawings.
[0023]
First, the internal structure of the wedge roller type transmission common to the embodiments will be described in detail, and then the embodiments will be described.
[0024]
(Internal structure of wedge roller type transmission)
FIG. 1 is a cross-sectional view of a driving device for a driven body provided with a wedge roller type transmission according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the wedge roller type transmission having a one-way clutch function along the line bb in FIG. 1, FIG. 3 is a diagram illustrating the operation of the wedge roller type transmission, and FIG. It is sectional drawing of the wedge roller type transmission which can transmit a torque at the time of rotation of both reverse directions.
[0025]
In this embodiment, the wedge roller type transmission A functions as a speed reducer having the high speed side shaft 17 as an input side and the low speed side shaft 3 (outer ring side) as an output side. However, the present device can also be applied to a speed-increasing gear having a high-speed side shaft (outer ring side) as an input side.
[0026]
Also, as shown in FIG. 2, the wedge roller type transmission A has a one-way clutch function that transmits torque during forward rotation, but does not transmit torque when rotating reversely, As shown in FIG. 7, torque may be transmitted during both forward and reverse rotations.
[0027]
In a wedge roller type transmission A according to an embodiment of the present invention, a housing 2 which is a partition plate is fixed to a substantially cylindrical housing 1 in FIGS. A low-speed side shaft 3 is rotatably supported by the housing 1, and a disc-shaped member 4 is integrally provided at an end of the low-speed side shaft 3 in the housing 1. An outer ring 32 is fixedly attached to the portion.
[0028]
The high-speed side shaft 17 is eccentrically (offset) with respect to the low-speed side shaft 3 and the outer ring 32 and is rotatably provided in the housing 2 serving as a partition plate.
[0029]
As shown in FIG. 2, between the high-speed side shaft 17 on the input side and the low-speed side outer ring 32 on the output side, a large-diameter guide roller 37a, a small-diameter guide roller 37b, and a movable roller that moves during torque transmission. 38 are interposed.
[0030]
As shown in FIG. 3, the support shaft 39 b that rotatably supports the movable roller 38 is configured to be movable between the high-speed side shaft 17 and the outer ring 32 in a direction that bites into a “wedge”. It is urged by an elastic member 47 (see FIG. 2) such as a compression spring installed in the cylinder hole 46 in a direction to bite into the “wedge”.
[0031]
As a result, as shown in FIG. 3, during normal rotation, the movable roller 38 moves between the high-speed side shaft 17 and the outer ring 32 in a direction to bite into a “wedge”, and generates a pressing force Fc. A traction force is generated by this Fc, and torque can be transmitted.
[0032]
On the other hand, at the time of reverse rotation, the movable roller 38 moves in a direction away from the “wedge”, the pressing force Fc becomes zero, the high-speed side shaft 17 idles, and the torque cannot be transmitted to the outer ring 32.
[0033]
As shown in FIG. 2, between the inner peripheral surface of the outer race 32 and the outer peripheral surface of the distal end portion of the high-speed shaft 17, there is provided an annular space 36 whose radial width is not uniform in the circumferential direction.
[0034]
In the annular space 36, two guide rollers 37a and 37b and one movable roller 38 are installed to constitute the wedge roller type transmission A. In FIG. 2, the movable roller 38 is partially cut away. Three support shafts 39a, 39a, 39b are provided in the annular space 36 for installing these rollers 37a, 37b, 38. Of the three support shafts 39a, 39a, 39b, the two support shafts 39a, 39a are press-fitted and fixed at both ends to fitting holes 40, 40 formed in the housing 2 and the connecting plate 14. . Therefore, the two support shafts 39a, 39a are not displaced in the circumferential direction or the diametric direction in the annular space 36. On the other hand, of the three support shafts 39a, 39a, 39b, the other one of the support shafts 39b located on the upper left side of FIG. The outer ring 32 is supported so as to be slightly displaceable in the circumferential and diametric directions. For this purpose, a support hole 41 having an inner diameter larger than the outer diameter of the support shaft 39b is formed in a part of the housing 2 and the connecting plate 14 which is aligned with both ends of the one support shaft 39b. Both ends of the support shaft 39b are loosely engaged with these support holes 41.
[0035]
The guide rollers 37a, 37b and the movable roller 38 are respectively mounted around the intermediate portions of the support shafts 39a, 39a, 39b supported as described above, by bearings such as radial needle bearings 42, 42, respectively. The bearing is rotatably supported by a bearing (not shown). In order to connect and fix the connecting plate 14 to the housing 2, the projecting portions 27, 27 projecting from one side of the connecting plate 14 are provided with the respective guide rollers with respect to the circumferential direction of the connecting plate 14. 37a, 37b and between the movable roller 38. In other words, each of the protrusions 27 and 27 and each of the guide rollers 37a and 37b or the movable roller 38 are present alternately in the annular space 36 in the circumferential direction of the annular space 36. In addition, the outer peripheral surface of each of the guide rollers 37a, 37b or the movable roller 38 does not interfere with (rub against) the circumferential side surface of each of the protrusions 27, 27.
[0036]
In this way, the outer peripheral surfaces of the guide rollers 37a, 37b and the movable roller 38 rotatably supported between the housing 2 and the connecting plate 14 by the support shafts 39a, 39a, 39b, The transmission cylindrical surfaces 43a, 43a, and 43b abut against the drive-side cylindrical surface 44, which is the outer peripheral surface of the distal end portion of the high-speed shaft 17, and the driven-side cylindrical surface 45, which is the inner peripheral surface of the outer ring 32, respectively. Let me. As described above, the width in the radial direction of the annular space 36 in which the guide rollers 37a and 37b and the movable roller 38 are installed is not uniform in the circumferential direction. As described above, the outer diameters of the guide rollers 37a and 37b and the movable roller 38 are made different by the amount of making the width of the annular space 36 unequal in the circumferential direction. That is, of the guide rollers 37 a and 37 b and the movable roller 38, the movable roller 38 and the guide roller 37 b which are located on the side where the tip of the high speed side shaft 17 is eccentric with respect to the outer ring 32 (upper side in FIG. 2). The outer diameters are the same and relatively small. On the other hand, the outer diameter of the guide roller 37a located on the opposite side (lower side in FIG. 2) of the tip of the high-speed shaft 17 to the outer ring 32 is set to the movable roller 38 and the guide roller 37b. It is larger than the outside diameter. The power transmission cylindrical surfaces 43a, 43a, 43b, which are the outer peripheral surfaces of the guide rollers 37a, 37b and the movable roller 38, are brought into contact with the drive-side and driven-side cylindrical surfaces 44, 45, respectively. .
[0037]
Note that, of the guide rollers 37a, 37b and the movable roller 38, both ends of the support shafts 39a, 39a supporting the guide rollers 37a, 37b are, as described above, with respect to the housing 2 and the connecting plate 14 ( (Within the annular space 36). On the other hand, the support shaft 39b supporting the movable roller 38 causes a slight displacement in the circumferential direction and the diametric direction with respect to the housing 2 and the connecting plate 14 (in the annular space 36) as described above. We support as much as possible. Therefore, the movable roller 38 can also be slightly displaced in the annular space 36 in the circumferential direction and the diametric direction. The support shaft 39b supporting the movable roller 38 is rotatably supported on the support shaft 39b by an elastic member 47 such as a compression spring installed in the cylinder hole 46 of the housing 2 and the connecting plate 14. The roller 38 is elastically lightly pressed so as to move the roller 38 toward the narrow portion of the annular space 36.
[0038]
When the rotating shaft is rotationally driven by the wedge roller type transmission configured as described above, the driving force is input to the high-speed side shaft 17 to rotate the shaft in the clockwise direction in FIG. The rotation of the high-speed side shaft 17 is transmitted to the outer race 32 via the guide rollers 37a and 37b and the movable roller 38, and rotates the outer race 32 counterclockwise in FIG. Power transmission between the high-speed shaft 17 and the guide rollers 37a and 37b and the movable roller 38 and power transmission between the guide rollers 37a and 37b and the movable roller 38 and the outer ring 32 are all frictional. Since transmission is performed, noise and vibration generated during power transmission are low.
[0039]
Further, the movable roller 38 tends to bite into the narrow portion (the upper central portion in FIG. 2) of the annular space 36 with a force corresponding to the magnitude of the torque transmitted from the high-speed shaft 17 to the outer ring 32. It becomes. Therefore, a contact portion between the driven-side cylindrical surface 45, which is the inner peripheral surface of the outer ring 32, and the power transmission cylindrical surfaces 43a, 43a, 43b, which are the outer peripheral surfaces of the guide rollers 37a, 37b and the movable roller 38, In addition, the surface pressure of the contact portion between each of the power transmission cylindrical surfaces 43a, 43a, 43b and the drive-side cylindrical surface 44, which is the outer peripheral surface of the high-speed shaft 17, is higher as the torque is larger. Become. Conversely, when the torque is small, the surface pressure of each contact portion is low. For this reason, the torque can be efficiently transmitted by setting the surface pressure of each contact portion to an appropriate value corresponding to the torque to be transmitted.
[0040]
That is, when the high speed side shaft 17 rotates clockwise in FIG. 2 and the outer ring 32 rotates counterclockwise, the movable roller 38 is driven by the driving side cylinder which is the outer peripheral surface of the high speed side shaft 17. When a force in the same direction as the pressing force of the elastic member 47 is received from the surface 44 and the driven-side cylindrical surface 45 which is the inner peripheral surface of the outer ring 32, the annular space 36 has a narrow portion, that is, FIG. Tend to move toward the upper center of the
[0041]
As a result, the power transmission cylindrical surface 43b, which is the outer peripheral surface of the movable roller 38, strongly presses the driven-side cylindrical surface 45 and the drive-side cylindrical surface 44. Then, an inner diameter side contact portion 48 which is a contact portion between the power transmission cylindrical surface 43b and the driving side cylindrical surface 44, and a contact between the power transmission cylindrical surface 43b and the driven side cylindrical surface 45. The contact pressure of the outer diameter side contact portion 49, which is the contact portion, increases. As described above, when the contact pressure of the inner and outer contact portions 48 and 49 with respect to the movable roller 38 increases, the movable roller 38 is pressed by the power transmission cylindrical surface 43b which is the outer peripheral surface of the movable roller 38. The high-speed side shaft 17 and the outer ring 32 are slightly displaced in the diameter direction due to elastic deformation and assembling clearance. As a result, the contact pressure of both the inner and outer contact portions 48 and 49 with respect to the guide rollers 37a and 37b increases. The rotational force of the high-speed shaft 17 is transmitted to the outer ring via the guide rollers 37a and 37b and the movable roller 38 based on the frictional engagement between the inner and outer diameter contact portions 48 and 49. 32.
[0042]
As described above, the force for moving the movable roller 38 toward the narrow portion of the annular space 36 depends on the magnitude of the rotational driving force transmitted from the high-speed shaft 17 to the outer ring 32. Change. The greater the force, the higher the contact pressure between the inner diameter side and the outer diameter side contact portions 48, 49. Therefore, based on such an operation, the contact pressure according to the transmitted rotational driving force is automatically selected, and the transmission efficiency of the wedge roller type transmission A can be secured.
[0043]
In the case of the example shown in FIG. 2, the wedge roller type transmission A has a one-way clutch function, and the rotation speed of the outer ring 32 matches the rotation speed of the high speed side shaft 17, that is, the high speed. When the rotation speed of the side shaft 17 is higher than the speed obtained by multiplying the reduction ratio of the wedge roller type transmission A, the connection of the wedge roller type transmission A is disconnected. That is, in this case, the movable roller 38 is displaced toward the wide side (the lower left side in FIG. 2) of the annular space 36 against the elasticity of the elastic member 47. As a result, the contact pressure between the inner diameter side and the outer diameter side contact portions 48 and 49 is reduced or lost, and the rotation of the high-speed shaft 17 is not transmitted to the outer ring 32.
[0044]
Next, a wedge roller type transmission shown in FIG. 4 that can transmit torque when rotating in both forward and reverse directions will be described.
[0045]
FIG. 4 shows a structure in which the high-speed shaft 17 (see FIG. 1) is rotatable in both clockwise and counterclockwise directions. In such a configuration of the present example, one guide roller 37 and two movable rollers 38a and 38b are used as the three rollers constituting the wedge roller type transmission A. . Among them, the roller installed in the widest part of the annular space 36 is a guide roller 37 having a relatively large diameter and the installation position does not change. On the other hand, a pair of rollers provided so as to sandwich the portion where the width of the annular space 36 becomes the narrowest is a movable roller 38a which has a relatively small diameter and enables a slight displacement in the circumferential and diametric directions. , 38b. The support shafts 39b and 39b supporting the movable rollers 38a and 38b are elastically pressed toward the narrowest portion of the annular space 36, respectively.
[0046]
In the case of the structure of the present embodiment configured as described above, when the high-speed shaft 17 rotates clockwise in FIG. 4, the movable roller 38a on the left side in FIG. Bite into the part. On the other hand, when the high-speed side shaft 17 rotates counterclockwise in FIG. 4, the movable roller 38b on the right side in FIG. 4 cuts into the narrowed portion of the annular space 36. Further, in the case of this example, in order to support both ends of the support shafts 39b, 39b supporting the movable rollers 38a, 38b, the annular shape of the support holes 41a, 41a formed in the housing 2 and the connecting plate 14 is set. The length of the space 36 in the circumferential direction is regulated. More specifically, the position of the end of each of the support holes 41a, 41a on the side where the width of the annular space 36 is wide (the lower side in FIG. 4) is more than that in the case shown in FIG. The annular space 36 is brought closer to the position where the width is narrowest. The movable rollers 38a and 38b are prevented from retreating excessively to the wide side of the annular space 36.
[0047]
In the case of the present embodiment configured as described above, even when the high-speed side shaft 17 rotates in either the clockwise or counterclockwise direction, any of the movable rollers 38a (38b) has the width of the annular space 36. The movable roller 38a (38b) bites into the narrow portion, and the contact pressure between the inner and outer contact portions 48 and 49 with respect to the movable roller 38a (38b) is increased. On the other hand, the retractable amount of the movable roller 38b (38a) displaced in the direction of retracting from the narrow portion of the annular space 36 is also limited. As a result, with respect to both the movable rollers 38a and 38b and the guide roller 37, the contact pressures of the contact portions 48 and 49 on the inner diameter side and the outer diameter side are sufficiently increased, and from the high speed side shaft 17 to the outer ring 32, Motion can be transmitted efficiently. Except for enabling the transmission of power in both the clockwise and counterclockwise directions from the high-speed side shaft 17 to the outer ring 32 in this manner, it is the same as the case described above with reference to FIG. I do.
[0048]
(Embodiment of the present invention)
FIG. 1 is a cross-sectional view of a driving device for a driven body including a wedge roller type transmission according to an embodiment of the present invention. FIG. 5 is a schematic cross-sectional view of a digital full-color tandem-type copying machine according to an embodiment of the present invention. FIG. 6 is a graph showing the relationship between the traction coefficient and the slip ratio.
[0049]
As shown in FIG. 5, a description will be given of an example in which an embodiment of a device for driving a rotating body according to the present invention is applied to a digital full-color tandem-type copying machine (hereinafter, simply referred to as "copying machine").
[0050]
FIG. 5 is a diagram showing the entire configuration of the copying machine 101. As shown in FIG. 1, the copying machine 101 includes an image reader unit 110 for reading a document image, and a printer unit 120 for printing the read image on a recording sheet S and reproducing it.
[0051]
The image reader unit 110 is a publicly known one that reads an image of a document placed on a document glass plate (not shown) by moving a scanner. The document image includes red (R), green (G), and blue. The image is separated into three colors (B) and converted into electric signals by a CCD image sensor (hereinafter, referred to as a “CCD sensor”) (not shown), thereby obtaining R, G, and B image data of the document.
[0052]
The image data for each color component obtained by the image reader unit 110 undergoes various data processing in the control unit 100, and is further processed for each of cyan (C), magenta (M), yellow (Y), and black (K). The image data is converted into image data of a reproduced color (hereinafter, each reproduced color of cyan, magenta, yellow, and black is represented by C, M, Y, and K, and the numbers of components related to each reproduced color are C, M, and Y and K are added as subscripts). The image data is temporarily stored in the image memory in the control unit 100 for each reproduced color, and is read out for each scanning line in synchronization with the supply of the recording sheet S, and becomes a drive signal of the laser diode.
[0053]
The printer unit 120 forms an image by an electrophotographic method, and includes a recording sheet conveying unit 130 having a conveying belt 131 stretched thereon, and an upstream side (hereinafter, referred to as a recording sheet conveying direction) opposed to the conveying belt 131. C, M, Y, and K image processing units 140C to 140K arranged at predetermined intervals from the “upstream side” to the downstream side in the transport direction (hereinafter, simply referred to as “downstream side”). Exposure scanning units 150C to 150K provided corresponding to the image processing units 140C to 140K, a sheet feeding unit 160 arranged upstream of the recording sheet conveying unit 130, a fixing unit 170 arranged downstream, and the like. Is provided.
[0054]
The recording sheet conveying unit 130 sequentially conveys the recording sheets S fed one by one from the sheet feeding unit 160 to the transfer positions immediately below the photosensitive drums 141C to 141K and the fixing device 170. A belt 131, a driving roller 132, a driven roller 133, and a tension roller 134 on which the belt is stretched, a belt static eliminator 135 for eliminating charges charged on the transport belt 131, and a belt cleaner for cleaning the outer peripheral surface of the transport belt 131 136 and the like.
[0055]
The tension roller 134 is pulled in the direction of arrow d by a tension spring (not shown), whereby the tension of the transport belt 131 is kept constant, and the drive roller 132 is moved in the direction of arrow b by a motor (not shown). The conveyor belt 131 is driven to rotate so that the transport belt 131 runs in the direction of arrow c at a high system speed when copying on plain paper and at a low system speed which is half the high system speed when copying on thick paper. Has become.
[0056]
The exposure scanning units 150C to 150K emit a laser beam receiving a drive signal output from the control unit 100, and deflect the laser beam to expose the photosensitive drums 141C to 141K in the main scanning direction. A polygon mirror and the like for scanning are provided.
[0057]
The image processing units 140C to 140K are configured around photoconductor drums 141C to 141K having the same diameter, which are driven to rotate at the system speed in the direction of the arrow a in the drawing, and cleaners 142C to 142K arranged around the photoconductor drums. It includes charging chargers 143C to 143K, developing devices 144C to 144K, and transfer chargers 145C to 145K disposed directly below the photosensitive drums 141C to 141K via the transport belt 131.
[0058]
The paper supply unit 160 includes a paper supply cassette 161 for storing recording sheets S of a predetermined size in a stacked state, a paper supply roller 162 for feeding out the recording sheets S from the paper supply cassette 161, a separation roller 163, There are provided vertical conveyance rollers 164a and 164b, a timing roller 165 for setting a timing for feeding out the recording sheet S, and the like. The paper feed unit 160 includes a paper feed roller 167 for feeding out the recording sheet S set on the manual feed table 166, and a separating roller 168.
[0059]
Next, the operation will be described. If the recording sheet S is thick paper, it is unlikely to bend, so that when the recording sheet S is transported from the paper feed cassette to the timing roller 165 via the vertical transport rollers 164a and 164b, there is a high possibility that a paper jam occurs. For this reason, in the copying machine 101, the thick paper is set on the manual feed table 166. On the upstream side of the paper feed roller 167, a recording sheet detection sensor for detecting the recording sheet S set on the manual feed table 166 is provided. When the recording sheet detection sensor detects the recording sheet, The control unit 100 sets the low system speed to the high system speed when a recording sheet is not detected.
[0060]
The laser diodes of the exposure scanning units 150C to 150K receive the drive signal from the control unit 100 and emit laser light, respectively, and this laser light is reflected and deflected by the mirror surface of the polygon mirror rotating at a constant speed. Then, the surfaces of the photosensitive drums 141C to 141K are exposed and scanned. Before the photosensitive drums 141C to 141K receive the exposure, the remaining toner on the surface is removed by the cleaners 142C to 142K, and further, the photosensitive drums are irradiated with an eraser lamp (not shown) to remove the electric charge. When the laser beam is exposed to the laser beam in the uniformly charged state, an electrostatic latent image is formed on the surfaces of the photosensitive drums 141C to 141K. Each of the electrostatic latent images is developed by a developing unit 144C to 144K for each color, whereby C, M, Y, and K toner images are formed on the surfaces of the photosensitive drums 141C to 141K.
[0061]
On the other hand, the recording sheet S stored in the sheet cassette 161 or the recording sheet S set on the manual feed table 166 is guided to the timing roller 165, and the timing roller 165 forms an image on the photosensitive drums 141C to 141K. The toner images of each color are sequentially transferred onto the recording sheet S conveyed by the conveyance belt 131 in synchronization with the operation and conveyed by the conveyance belt 131 by the electrostatic force of the transfer chargers 145C to 145K. At this time, the image forming operation of each color is performed with a timing shifted from the upstream side to the downstream side so that the toner image is transferred to the same position of the conveyed recording sheet S in a superimposed manner. You.
[0062]
The recording sheet S on which the toner images of each color are transferred in a multiplex manner is conveyed to a fixing unit 170 where the toner particles on the surface of the recording sheet S are pressed at a high temperature by a pair of rotors rotating in synchronization with the system speed. Then, the sheet is discharged onto the sheet discharge tray 171, thereby completing the image formation based on the image data of the document.
[0063]
An operation panel (not shown) is provided at an easy-to-operate position on the upper side on the front side of the image reader unit 110, so that the operator can set a copy mode such as the number of copies and the copy density, or Copy start can be specified.
[0064]
Next, as shown in FIG. 1, in the driving device for the driven body according to the present embodiment, the wedge roller type transmission A is a reduction gear, and the drive shaft 51 of the electric motor 50 is attached to the high speed side shaft 17. Are integrally connected. Note that the wedge roller type transmission A and the electric motor 50 are integrally formed, and are configured as a motor-integrated wedge roller type transmission. The electric motor 50 includes a stator 52 fixed to a housing and a rotor 53 integrated with the drive shaft 51.
[0065]
The rotating body X is mounted on the low-speed side shaft 3. In the image forming apparatus or the printing apparatus, the rotated object X is, for example, a photosensitive drum 141C to 141K, a transfer roller, paper transport rollers 162 and 167 (paper feed rollers), a paper transport belt drive roller 132, a pressure roller, and a heat roller. A roller, a charging roller, a feed roller, a mag roller, a developing roller, a platen roller, or an impression cylinder. These are examples, and the rotating body X is not limited to these.
[0066]
Further, the wedge roller type speed reducer A may be of a type capable of transmitting drive only in one rotation direction (FIG. 2). In this case, it is used for a portion which rotates only in one direction such as a transfer roll and a photosensitive drum. Thus, the possibility of paper jam due to a malfunction of the motor can be eliminated.
[0067]
Further, the wedge-roller type speed reducer A may be of a type capable of transmitting drive in both rotation directions (FIG. 4), and is used for a part which requires rotation in both directions, for example, a paper feeder for double-sided printing.
[0068]
Further, in the traction drive device (wedge roller type speed reducer A), a slight slip occurs in the power transmission unit, but the slip is 0.5% or less, which is not a problem in practical use. FIG. 6 shows the relationship between the slip ratio and the traction coefficient. In an application such as a printing machine, it is desirable to design the slippage to be small for the above-described reason. Therefore, the traction coefficient is preferably set to a low value (0.08 or less).
[0069]
According to the present embodiment, since the traction drive type speed reducer (in particular, the wedge roller type speed reducer A) is used, quiet and smooth power transmission can be performed, and high transmission efficiency can be obtained. The size, weight, and cost can be reduced.
[0070]
Further, the traction drive device (wedge roller type speed reducer A) is a friction drive and has no backlash, so that the accuracy of paper feeding is improved and problems such as color unevenness are eliminated.
[0071]
Further, since there is no gear engagement, no noise is generated. The noise level generated by the entire apparatus can be suppressed, and the commercial value especially for home use and office use can be enhanced.
[0072]
Further, since there is no need to use a motor in which stepping motors are directly connected, the motor can be downsized, the controller can be simplified, and the power supply can be simplified.
[0073]
Further, unlike the shrink-fit type planetary traction speed reducer, the wedge roller type speed reducer A has a torque-sensitive pressing force generating mechanism, so that the transmission efficiency is high (98% or more). Therefore, the drive current of the motor can be reduced, and the power consumption of the entire apparatus can be reduced.
[0074]
Further, if the wedge roller type speed reducer A has a characteristic of transmitting drive in only one direction (one-way clutch function), for example, even if a malfunction occurs in the motor, the paper is not fed in the reverse direction, It also has aspects of a fail-safe mechanism that can eliminate the possibility of paper jams.
[0075]
In the above embodiment, a digital full-color tandem copying machine has been described as an example. However, a driving device for a rotating body including a wedge roller type transmission according to the present invention is a color laser printer, a monochrome laser printer, a monochrome copying machine. It can also be used for ink jet printers, dot printers, thermal transfer printers, thermal printers, and even printing presses and rotary presses.
[0076]
The present invention is not limited to the above-described embodiment, but can be variously modified.
[0077]
【The invention's effect】
As described above, according to the present invention, since a traction drive type speed reducer (particularly, a wedge roller type speed reducer) is used, quiet and smooth power transmission can be performed, and high transmission efficiency can be obtained. It is possible to reduce the size, weight and cost.
[0078]
Further, the traction drive device (wedge roller type speed reducer) is a friction drive and has no backlash, so that the accuracy of paper feeding is improved and defects such as color unevenness are eliminated.
[0079]
Further, since there is no gear engagement, no noise is generated. The noise level generated by the entire apparatus can be suppressed, and the commercial value especially for home use and office use can be enhanced.
[0080]
Further, since there is no need to use a motor in which stepping motors are directly connected, the motor can be downsized, the controller can be simplified, and the power supply can be simplified.
[0081]
Further, unlike the shrink fit type planetary traction speed reducer, the wedge roller type speed reducer has a torque-sensitive pressing force generating mechanism, so that the transmission efficiency is high (98% or more). Therefore, the drive current of the motor can be reduced, and the power consumption of the entire apparatus can be reduced.
[0082]
Further, since the wedge roller type speed reducer has a characteristic of transmitting the drive only in one direction (one-way clutch function), for example, even if the motor malfunctions, the paper is not fed in the reverse direction, and the paper is not sent in the reverse direction. It also has aspects of a fail-safe mechanism that can eliminate the possibility of clogging.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a driving device for a rotating body including a wedge roller type transmission according to an embodiment of the present invention.
FIG. 2 is a sectional view taken along the line bb in FIG. 1;
FIG. 3 is a diagram illustrating the operation of a wedge roller type transmission.
FIG. 4 is a cross-sectional view of a wedge roller type transmission capable of transmitting torque when rotating in both forward and reverse directions according to the present invention.
FIG. 5 is a schematic cross-sectional view of a digital full-color tandem-type copying machine according to an embodiment of the present invention.
FIG. 6 is a graph showing a relationship between a traction coefficient and a slip ratio.
[Explanation of symbols]
1 Housing
2 Housing (partition plate)
3 Low speed shaft
4 Disc-shaped members
14 Connecting plate
17 High speed side shaft
22 Plain bearing
26 Preload member
27 Projection
31 Deep groove ball bearings
32 Outer ring (low-speed side shaft)
36 Annular space
37, 37a, 37b Guide roller
38, 38a, 38b Movable roller
39a, 39b Support shaft
40 mating hole
41, 41a support holes
42 Radial needle bearing
43 Cylindrical surface for power transmission
44 Drive side cylindrical surface
45 Driven side cylindrical surface
46 Cylinder hole
47 Elastic material
48 Inside contact part
49 Outer diameter side contact part
50 electric motor
51 Drive shaft
100 control unit
101 Copier
110 Image Reader
120 Printer section
130 Recording sheet transport section
131 conveyor belt
132 drive roller
133 driven roller
134 tension roller
135 Belt static eliminator
136 Belt cleaner
140 Image processing section
141 Photoconductor drum
142 cleaner
143 charge
144 developer
145 Transfer charge
150 Exposure scanning section
160 paper feeder
161 paper cassette
162 paper feed roller
163 Handling roller
164a, b Vertical transport roller
165 Timing roller
166 manual feed table
167 Paper feed roller
168 Handling roller
170 fixing unit
171 Output tray
A Wedge roller type transmission (reduction gear)
X rotated object

Claims (5)

In a driving device that rotates a rotating body attached to an image forming apparatus or a printing apparatus,
A driven body is connected to the low-speed shaft of the traction drive type speed reducer, and the drive shaft of the electric motor is connected to the high-speed shaft, or the high-speed shaft is the drive shaft of the electric motor itself. Driving device for rotating body. The rotating member may be any one of a photosensitive drum, a transfer roller, a paper transport roller, a drive roller for a paper transport belt, a pressure roller, a heat roller, a charging roller, a feed roller, a mag roller, a developing roller, a platen roller, and an impression cylinder. 2. The driving device for a driven body according to claim 1, wherein: The traction drive type speed reducer is rotatably supported by a housing and has a low-speed side shaft provided with an outer ring at one end, and a high-speed shaft eccentrically supported by the housing and eccentric with respect to the low-speed side shaft and the outer ring. A friction roller type speed reducer utilizing a wedge action comprising a side shaft, at least one guide roller and at least one movable roller, rotatably supported between the outer ring and the high speed side shaft. 3. The driving device for a rotating body according to claim 1, wherein 4. The rotating body according to claim 3, wherein the wedge roller type speed reducer has a one-way clutch function that transmits torque during normal rotation, and does not transmit torque during reverse rotation. Drive. The driving device for a driven body according to claim 3, wherein the wedge roller type speed reducer transmits torque when rotating in both forward and reverse directions.

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