JP4855165B2 - Paper feeding device, image forming device - Google Patents

Description

  The present invention relates to a paper feeding device and an image forming apparatus, and more particularly, to a paper feeding device and an image forming apparatus that automatically correct skew of inserted paper.

  Conventionally, as an image forming apparatus, a printer is used in which a sheet is manually inserted in a substantially horizontal direction into a sheet insertion portion, and the sheet is conveyed to perform printing. In such a printer, if the paper is carried into a printing unit configured with a print head or the like while being inclined, characters and the like are printed obliquely on the paper. When printing is performed on the skewed paper as described above, if the paper is a slip, printing cannot be performed at a predetermined position in the column.

  In view of this, such a printer is provided with a skew correction device that corrects the inclination upstream of the printing unit so that the paper is oriented correctly.

  Conventionally, as such a skew feeding correction device, there is a device that feeds rotating feed members in contact with both upper and lower surfaces of a sheet and feeds the leading edge of the sheet against a pair of feed rollers, thereby correcting the skew of the sheet.

  Patent Document 1 discloses a frame having a sheet conveying surface, a shaft rotatably disposed above the sheet conveying surface, and a shaft spaced apart in the axial direction of the shaft and at different angles in the circumferential direction. And a rotation device that rotates the shaft, and conveys the sheet along the sheet conveyance surface toward the sheet conveyance roller in the printer by the projection, and the sheet conveyance roller. Is described in which the skew of the sheet is corrected.

  In Patent Document 2, a skew feeding correction roller is provided on the upstream side in the transport direction of a pair of front feed rollers for transporting a print medium to a print head. The skew feeding correction roller is rotated by a motor via a belt, and is fed to the front feed roller. An abutting portion is disposed on the downstream side of the roller pair. When the printing medium is inserted, the skew feeding correction roller is driven to rotate, and the leading end portion of the printing medium is abutted against the abutting portion. A document that corrects skew of a print medium is described.

JP 2002-347995 A JP 2005-15184 A

  By the way, as a sheet to be printed, there is a multiple copy sheet in which a plurality of sheets are overlapped and printed while being copied onto the overlapped sheet by applying energy from the outside. In such a multiple copy paper, the paper that is usually arranged on the uppermost side is thinner and less stiff than other papers in order to make a good copy.

  When the above-described multiple copy paper is applied to the above-described conventional skew correction device, when the uppermost sheet is fed in contact with the feeding member, the upper sheet is separated from the lower sheet to cause a deviation. There is. That is, in the case of the above-mentioned Patent Document 1, the roller contacts the uppermost sheet, and in the case of Patent Document 2, the protrusion contacts the uppermost sheet so that the uppermost sheet It is separated from other sheets located at the lower part and shifted. If the paper is displaced in this way, characters or the like cannot be printed at the correct position on the superimposed paper.

  Accordingly, the present invention can correct skew feeding without causing a deviation between the uppermost sheet and the lower sheet even in a multiple copy sheet in which a plurality of sheets are superimposed. An object of the present invention is to provide a paper feeding device and an image forming apparatus that can be used.

  A paper feeding device for solving the problems in the present invention is arranged in a paper transport path leading to the feed roller in a paper feeding device for correcting skew feeding of a paper supplied to a feed roller that sends the paper to a printing unit. A sheet position correction roller that contacts one surface of the sheet supplied to the sheet transfer path and feeds the sheet to the feed roller side, and a skew that faces the sheet position correction roller and is close to the sheet position correction roller. A sheet contact mechanism that moves between two positions of a correction position and a separated retracted position and contacts the other surface of the sheet at a plurality of positions when positioned at the skew correction position, and movement of the sheet contact mechanism. A movement limiting mechanism for limiting between the skew correction position and the retracted position, two gear trains for driving the paper position correction roller and the paper contact mechanism with a single motor, and the paper contact A torque limiter that is arranged in a gear train that drives the structure and that transmits the power of the motor to the paper contact mechanism within a range restricted by the movement restriction mechanism, and controls the motor to tilt the paper contact mechanism. And a control device that moves the paper position correction roller in the paper feed direction while moving it to a line correction position.

  According to the present invention, the sheet is sent to the sheet position correction roller at the lower part thereof, and the upper part of the sheet is merely contacted by the sheet contact mechanism and does not act on the driving force. Can be corrected without being separated from the recording material arranged underneath.

  An embodiment of the present invention will be described with reference to FIGS. In this embodiment, an example of application to an office machine P having a display, a keyboard, and the like on the front surface of the housing is shown. Hereinafter, the mechanical configuration of the office machine P according to this example will be described with reference to FIGS.

  FIG. 1 is a side view showing an office machine P as a first embodiment according to the present invention. In the drawing, a part of the housing 1 for housing each part is cut out. A display 5 for displaying information toward the operator is provided on the front surface of the housing 1, and a keyboard 6 used for the operator to operate the office machine P is provided below the display 5. Further, a manual feed slot 7 into which a sheet S (for example, a multi-copy single sheet) is inserted is formed between the display 5 on the front surface of the housing 1 and the keyboard 6. A sheet path 8 for guiding the sheet S from the sheet 7 toward the sheet discharge port 10 formed on the upper surface of the housing 1 is formed.

  In this paper path 8, a plurality of pairs of transport rollers 9 are arranged as a transport unit that transports the paper S inserted into the paper path 8 from the manual feed slot 7, and the transport roller 9 rotates to rotate the paper S. Is guided and conveyed in the direction of the paper discharge port 10. The transport roller 9 is driven to rotate by a motor (not shown). The paper path 8 is provided with a printing unit 2 that performs printing on the paper S guided and conveyed along the paper path 8. The print unit 2 includes a print head 3 and a flat platen 4 that are arranged to face each other via a paper path 8, and the print head 3 is a carrier shaft (not shown) arranged along the longitudinal direction of the platen 4. And is reciprocally driven by a drive unit (not shown). The platen 4 may be a platen roller or the like. A paper discharge roller 11 is arranged in the paper path 8 at the top of the printing unit 2 as a transport unit that transports the printed paper S toward the paper discharge port 10.

  Next, a manual feed type paper feeder disposed in the office machine P according to this example will be described with reference to FIGS.

  2 is a side view showing a paper feeding device according to an embodiment of the office machine, FIG. 3 is a perspective view showing a driving system of the paper feeding device, FIG. 4 is a plan view showing the driving system of the paper feeding device, and FIG. FIG. 6 is a schematic side view showing the operating state of the paper contact mechanism in the paper supply device, and FIG. 7 is a schematic side view showing the operating state of the paper contact mechanism in the paper supply device. .

  In this example, as shown in FIG. 2, the paper feeding device 100 is disposed on the upstream side of the paper path 8, and is disposed on the most downstream side of the paper path 8 from the manual feed port 7 of the paper S. A paper delivery path to the feed roller 9a is provided, and the skewed paper S is sent out. The paper feeding device 100 is disposed adjacent to the support plate 101 constituting the paper delivery path, contacts the lower surface of the supplied paper S, and rotates its drive shaft 121 to feed the paper to the feed roller 9a side. A sheet contact mechanism including a sheet position correction roller 120 to be fed to the sheet, and a plurality of sheet contact portions 142 disposed above the sheet position correction roller 120 and disposed in the sheet width direction of the sheet feeding device 100 driven by the drive shaft 141. 140, and a driving device 110 that also serves as a roller driving device that drives the paper position correction roller 120 and a contact portion driving device that drives the paper contact mechanism 140.

  As shown in FIGS. 3 and 6, the paper position correction roller 120 is formed by arranging a contact roller portion 122 having a diameter larger than that of the drive shaft 121 at a location corresponding to the location of the paper contact portion 142 of the drive shaft 121. Is done.

  The paper contact mechanism 140 includes a drive shaft 141, a plurality of cylindrical base portions 144 rotatably disposed on the drive shaft 141, arm members 143 extending from these base portions, and the arm members. And the paper contact portion 142 formed at the front end of 143. Further, between the paper contact mechanism 140 and the base portion 144, a string spring 145 that urges the arm member 143 in the contact direction is disposed.

  Here, the base portion 144 is urged by a coil spring 145 disposed between the base portion 144 and the drive shaft 141 when the paper contact portion 142 does not contact other members.

  Further, the drive shaft 141 is driven to reciprocate by the drive device 110, and the sheet contact portion 142 is moved away from the skew correction position (position i in FIG. 6) close to the sheet position correction roller 120, and the retracted position (in FIG. 6). It can be moved to position ii, FIG. 7).

  Note that reference numeral 220 in FIG. 3 denotes a paper detection device, which indicates a paper sensor that optically detects the paper S.

  The paper contact portion 142, the arm member 143, and the base portion 144 are integrally formed of a synthetic resin having a small coefficient of friction with the paper S. Further, when the paper contact portion 142 is disposed at the skew correction position, the paper contact portion 142 is located at a position sandwiching the position B where the paper position correction roller 120 contacts the paper as shown in FIG. The shape is in contact with the sheet S at two locations C and D. Accordingly, the sheet S is curved at the three positions B and C and D, and the sheet S comes into contact with the contact roller portion 122 by its elastic force. For this reason, the paper S is not sandwiched between the paper contact portion 242 and the contact roller portion 122, and the paper S is not strongly pressed by the paper contact portion 242. For this reason, drag caused by friction between the sheet contact portion 242 and the sheet S is not increased, and separation of multiple copy sheets can be effectively prevented.

  The driving device 110 of this example is controlled by a control unit 210 (FIG. 11), which is a control device, to drive the paper position correction roller 120 and the paper contact mechanism 140 to perform skew correction.

  The contact roller portion 122 is made of synthetic rubber, and the friction coefficient between the contact roller portion 122 and the paper S is larger than the friction coefficient between the paper S and the paper contact portion 142 of the paper contact mechanism 140. It is selected to be. Since the friction coefficient described above varies depending on the type, width, and other conditions of the paper S to be used, an appropriate material may be selected in advance through experiments.

  Next, the driving device 110 according to this example will be described. As described above, the driving device 110 drives the paper position correction roller 120 and the paper contact mechanism 140.

  The driving device 110 is driven by a skew correction motor 160 which is a single motor. The skew correction motor 160 is a pulse motor, and a pinion gear 162 is disposed on the output shaft 161 thereof.

  The pinion gear 162 meshes with the small diameter portion 163b of the first two-stage gear 163 that connects the large diameter portion 163a and the small diameter portion 163b. The large-diameter portion 163a of the first two-stage gear 163 is meshed with the large-diameter portion 163a of the second two-stage gear 164 connecting the large-diameter portion 164a and the small-diameter portion 164b.

  A spur gear 165 to which the drive shaft 121 is connected is meshed with the large-diameter portion 164a of the second two-stage gear 164. The large diameter portion 164a and the spur gear 165 of the second two-stage gear 164 constitute a first gear train, and the drive shaft 121 is rotationally driven by the first gear train, and the contact roller portion 122 is rotated.

  On the other hand, a rotation conducting portion 166 having a torque limiter 180 is connected to the small diameter portion 164 b of the second two-stage gear 164. The rotation conducting portion 166 includes a large-diameter gear portion 166a that meshes with the small-diameter portion 164b, and a small-diameter gear portion 166b that is connected to the large-diameter gear portion 166a via a torque limiter 180. The flat gear 167 to which the drive shaft 141 is connected is meshed with the small diameter gear portion 166b of the rotation conducting portion 166.

  The second gear train is constituted by the small diameter portion 164b, the rotation conducting portion 166, and the spur gear 167 of the second two-stage gear 164, and the sheet contact mechanism 140 is driven by the second gear train.

  Further, the spur gear 167 is formed with a long hole 168 along the circumference at a predetermined position. Further, the spur gear 167 is inserted into a pin member 169, and this pin member 169 is disposed on the main body of the printer by fixing means (not shown). The long hole 168 and the pin member 169 constitute a movement restriction mechanism, and the long hole 168 includes a skew side end 168a and a retreat side end 168b.

  Therefore, the rotation range of the spur gear 167 is limited, and the sheet contact portion 142 of the sheet contact mechanism 140 can move only between the skew correction position and the retracted position described above.

  That is, the sheet contact mechanism 140 is positioned at the skew position as shown in FIG. 6 in a state where the pin member 169 is in contact with the skew-side end portion 168a. Further, the sheet contact mechanism 140 is positioned at the retracted position as shown in FIG. 7 with the pin member 169 in contact with the retracting side end 168b.

  The torque limiter 180 can be rotated in both forward and reverse directions, and a large-diameter gear portion 166a and a small-diameter gear portion 166b are connected to an input / output shaft thereof. Therefore, when the small-diameter gear portion 166b stops at the skew correction position or the retracted position, that is, the flat gear 167 comes into contact with both ends of the long hole 168 and the flat gear 167 does not rotate. However, the rotation of the large-diameter gear portion 166a is not limited by the idling of the torque limiter 180.

  That is, when the skew correction motor 160 rotates in one direction (forward direction), the paper position correction roller 120 is driven to rotate in the paper take-in direction by the first gear train. On the other hand, on the second gear train side, the small diameter gear portion 166b is driven to rotate from the large diameter gear portion 166a of the rotation conducting portion 166 via the torque limiter 180, and further, the flat gear 167 engaged with the small diameter gear portion 166b is driven. Then, the drive shaft 141 rotates the paper contact mechanism 140 toward the skew correction position. When the pin member 169 contacts the skew side end 168a of the long hole 168, the sheet contact mechanism 140 reaches the skew correction position and the rotation of the spur gear 167 is stopped. In this state, the small-diameter gear portion 166b meshing with the spur gear 167 stops, and the torque limiter 180 idles between the large-diameter gear portion 166a and the small-diameter gear portion 166b in the rotation conducting portion 166, and the large-diameter gear portion 166a The state is rotationally driven by the skew correction motor 160. For this reason, the paper position correction roller 120 is rotationally driven by the skew correction motor 160 regardless of the position of the paper contact mechanism 140.

  On the other hand, when the skew correction motor 160 rotates in the other direction (reverse direction), the paper position correction roller 120 is driven to rotate in the paper discharge direction by the first gear train. On the second gear train side, the small-diameter gear portion 166b is rotationally driven from the large-diameter gear portion 166a of the rotation conducting portion 166 via the torque limiter 180, and further, the flat gear 167 engaged with the small-diameter gear portion 166b is driven. The drive shaft 141 rotates the sheet contact mechanism 140 toward the retracted position. When the pin member 169 comes into contact with the retreat side end 168b of the long hole 168, the paper contact mechanism 140 reaches the retreat position and the rotation of the spur gear 167 is stopped.

  In this state, the small-diameter gear portion 166b meshing with the spur gear 167 stops, and the torque limiter 180 idles between the large-diameter gear portion 166a and the small-diameter gear portion 166b in the rotation conducting portion 166, and the large-diameter gear portion 166a The state is rotationally driven by the skew correction motor 160. For this reason, the paper position correction roller 120 is rotationally driven by the skew correction motor 160 regardless of the position of the paper contact mechanism 140.

  Incidentally, reference numeral 230 in the figure denotes an arm position sensor which is a contact member detection device for detecting the position of the paper contact mechanism. This arm position sensor 230 is composed of a photocoupler 232 and is a fan-shaped attachment attached to the drive shaft 141. The shielding plate 231 detects the position of the paper contact mechanism 140 by blocking the optical path of the photocoupler 232. Here, when the paper contact mechanism 140 is close to the paper position correction roller 120 and is in the skew correction position, the shielding plate 231 shields the optical path of the photocoupler 232 and is turned on, so that the paper contact mechanism 140 is in the retracted position. When moved, the shielding plate 231 goes off the optical path of the photocoupler 232 and is turned off.

  Next, the driving state of the paper feeding apparatus 100 according to this example will be described.

  FIG. 8 is a conceptual plan view showing the paper feeding device, and FIG. 9 is a conceptual side view showing the paper feeding device.

  In the paper feeding device 100 of this example, the paper contact portion 142 of the paper contact mechanism 140 is set to the skew correction position, and the paper S is disposed between the contact roller portion 122 and the paper contact portion 142, and the skew correction motor. When 160 is rotated in the forward direction, the contact roller unit 122 applies a driving force Ff in the direction of the feed roller 9a to the paper S disposed on the contact roller unit 122. This driving force Ff is generated by friction between the lower surface of the paper S and the contact roller portion 122.

  On the other hand, a drag Fr due to the frictional force between the two members is generated between the paper contact portion 142, the paper S, and the paper contact portion 142. The magnitude of the drag Fr is determined by the friction coefficient between the paper contact portion 142 and the paper S and the urging force of the chord spring 145. However, since a member having a small friction coefficient is used for the paper contact portion 142, the back surface of the paper S And the contact roller portion 122 is larger than the friction force between the surface of the paper S and the paper contact portion 142, and the paper is moved by the driving force Ff by the contact roller portion 122.

  Then, when the contact roller portion 122 is rotating, as shown in FIG. 8, when the sheet S is inserted obliquely and its leading front edge comes into contact with the feed roller 9a, the preceding contact roller portion. 122 idles so that the back surface of the paper S is rubbed. In addition, since the paper S does not move at the paper contact portion 142, no drag due to frictional force is generated. In this state, the sheet S is rotated around the contact point of the sheet S with the feed roller 9a by the frictional force of the other contact roller unit 122, and the leading edge of the sheet S abuts on the feed roller 9a and is skewed. It is corrected.

  Next, control of the paper feeder 100 of the office machine P according to this example will be described with reference to FIGS.

  FIG. 11 is a block diagram illustrating a control system of the sheet feeding device.

  The sheet feeding device 100 according to this example includes a control unit 210 that is a sequence controller, and controls the skew correction motor 160 to be driven. The control unit 210 is connected to a paper sensor 220 formed of an optical sensor as a paper detection device and an arm position sensor 230 as a contact member detection device that detects the position of the paper contact mechanism 140. The skew correction motor 160 is driven with a predetermined sequence.

  Hereinafter, drive control of the sheet feeding device 100 will be described with reference to FIGS.

  FIG. 12 is a flowchart showing a state of initialization control of the sheet feeding device.

  When the apparatus is activated, the control unit 210 first performs an initialization process. With this initialization process, the sheet contact mechanism 140 is moved to the retracted position. That is, when the power supply of the office machine P is turned on (step ST1), the skew correction motor 160 is driven to rotate in the reverse direction, that is, the direction in which the paper position correction roller 120 ejects the paper S for a predetermined time (step ST2). By the reverse rotation of the skew correction motor 160, the paper position correction roller 120 rotates in the direction in which the paper S is discharged, and the paper contact mechanism 140 moves to the retracted position.

  The skew correction motor 160 is driven for a time sufficient for the paper contact mechanism 140 to move from the skew correction position to the retracted position. Even if the skew correction motor 160 rotates after the paper contact mechanism 140 stops at the retracted position, the torque limiter 180 is idled so that no unnecessary load is applied to the skew correction motor 160.

  Thus, by this operation, the sheet feeding device 100 is in an initial state, and a state in which skew feeding correction can be performed.

  Next, control in the skew correction of the sheet feeding device 100 will be described.

  FIG. 13 is a flowchart showing the state of the skew correction control of the paper feeder, and FIG. 14 is a timing chart showing the state of the skew correction control of the paper feeder.

  First, when the paper is manually fed, the paper sensor 220 is turned on (step ST11). Then, the skew correction motor 160 is rotated in the forward direction (step ST12). As a result, the paper contact mechanism 140 moves to the skew correction position, and the paper contact portion 142 contacts the paper. In this state, the skew correction of the paper is started.

  Next, the feed motor is driven (step ST13), and the paper is transferred by the feed roller 9a. The paper sensor 220 is turned off by the passage of the paper S (step ST14), and the skew correction motor 160 is rotated in reverse (step ST15). By rotating the skew correction motor 160 in the reverse direction, the paper contact portion 142 is moved to the retracted position, and then the skew correction motor is stopped (step ST16).

  After these operations are finished, the feed motor is turned off and the printing operation is finished (step ST17).

  Therefore, according to the office machine P according to the present example, even if the manually fed paper is inserted obliquely, the skew is corrected well and is carried into the printing unit.

  In addition, since the driving force does not act on the upper side of the sheet when skew correction is performed, the recording sheet positioned at the top of the sheet does not separate from the lower recording sheet.

  As shown in FIG. 10B, the paper contact portion 242 of the paper contact portion 142 and the paper S at the skew correction position are substantially the same as the position a where the paper position correction roller 120 contacts the paper S. A gentle arc that touches can be drawn.

  Further, as shown in FIG. 8C, a roller 344 that is a rotating member that rotatably contacts the paper may be disposed at the tip of the arm member 343. The rotating member disposed at the tip of the arm can be a ball. In this case, the drag on the paper S due to friction is extremely small, and separation of multiple copy papers can be effectively prevented.

  Furthermore, as another embodiment, the arm member and the paper contact portion may be integrally formed with a material having elasticity, and the paper may be pressed by the elasticity of the arm member and the paper contact portion. In this case, a string spring or the like is not necessary.

  Next, a description will be given of the result of skew correction performed on the sheet feeding device according to the present embodiment. FIG. 15 is a table showing the shift amount of the multiple copy paper in the skew feeding correction of the paper feeding device according to this example and the comparative example.

  In this example, the lowermost layer (one layer) and the uppermost layer (5) when the skew correction of the multi-layer copy paper of five layers is actually performed in the apparatus described in the embodiment and in the first and second comparative examples. The deviation from the layer is measured.

  As Comparative Example 1, a paper feeder corresponding to Patent Document 1 was used. The paper feeding device includes a shaft rotatably disposed above the multiple copy paper, a protrusion provided on the shaft at an angle different in the circumferential direction at intervals in the axial direction of the shaft, and the shaft A rotating device that rotates the uppermost layer (5 layers) of the multiple copy paper by a protrusion along the sheet conveying surface toward the sheet conveying roller in the printer, and the sheet to the sheet conveying roller The skew of the multiple copy paper is corrected by abutting.

  As Comparative Example 2, the one corresponding to Patent Document 2 was used. This paper feed is rotated by bringing a skew feeding correction roller into contact with the uppermost layer of the multiple copy paper, and the leading end of the multiple copy paper is abutted against the abutting portion. It is to be corrected.

  In both of them, the rotation device or the skew feeding correction roller is brought into contact with the uppermost layer of the paper to correct the feeding skew.

  As the paper, a chain store unified slip (cut paper) was used. The chain store unified slip is composed of five layers, the lowermost layer (one layer) is thick paper, the other layers are thin paper, and the left side along the feed direction is temporarily bound with line glue. . In this comparison, the upper side of the sheet is inclined by a predetermined angle (0 degree, 5 degree, 10 degree) and inserted into each sheet feeding device, and the deviation dimension between the uppermost sheet and the lowermost sheet after passing through the apparatus is determined on the non-binding side. Measured with The measured value was positive when the uppermost sheet preceded the lowermost sheet, and negative when the uppermost sheet was delayed compared to the lowermost sheet. In addition, a low temperature (0 degree Celsius), a normal temperature (20 degree Celsius), and a high temperature (40 degree Celsius) were set as the environmental temperature of the measurement. In Comparative Example 2, skew correction could not be performed at 10 degrees.

  In Comparative Examples 1 and 2, the paper is also fed on the upper side of the paper. Occurred.

  On the other hand, in the sheet feeding device according to this example, the deviation between the lowermost layer (one layer) and the uppermost layer (5) layer is a maximum of −0.5 mm. It can be seen that the skew correction can be performed better than the skew correction apparatus of Patent Document 2.

Note that the measured value in the paper feeding device of the present application is negative because the transfer force is applied to the uppermost side of the multiple copy paper in Comparative Examples 1 and 2, whereas the multiple copy paper in the embodiment. This is probably because the transfer force is applied to the lowermost side.

1 is a side view showing an office machine that is an embodiment of an image forming apparatus according to the present invention. It is a side view which shows the paper feeder which concerns on embodiment of an office machine. FIG. 3 is a perspective view showing a drive system of a paper feeding device. FIG. 3 is a plan view showing a drive system of a paper feeding device. FIG. 4 is a side view showing a drive system of a paper feeding device. It is a schematic side view which shows a paper feeder. It is a schematic side view which shows a paper feeder. It is a plane conceptual diagram which shows a paper feeder. It is a side surface conceptual diagram which shows a paper feeder. (A), (b), (c) is a side conceptual diagram which shows the example of the paper contact mechanism of a paper feeder. FIG. 3 is a block diagram illustrating a control system of a sheet feeding device. 6 is a flowchart illustrating a state of initialization control of the sheet feeding device. 6 is a flowchart illustrating a state of skew correction control of the sheet feeding device. 6 is a timing chart illustrating a state of skew correction control of the sheet feeding device. 10 is a table showing the amount of deviation of multiple copy paper in skew correction between the paper feeding device according to this example and the comparative example.

Explanation of symbols

100 paper feeding device, 120 paper position correction roller, 140 paper contact mechanism, 160 skew correction motor (motor), 180 torque limiter, 210 control unit (control device), 220 paper sensor (paper detection device)

Claims (13)

In a paper feeding device that corrects skew of paper fed to a feed roller that feeds paper to a printing unit,
A paper position correction roller that is disposed in a paper transfer path that reaches the feed roller, and that contacts one surface of the paper supplied to the paper transfer path and sends the paper to the feed roller;
It moves between two positions, a skew correction position close to the paper position correction roller and close to the paper position correction roller, and a retracted position away from the paper position correction roller. A paper contact mechanism that contacts the surface at multiple locations;
A movement limiting mechanism that limits the movement of the paper contact mechanism between the skew correction position and the retracted position;
Two gear trains for driving the paper position correction roller and the paper contact mechanism with a single motor;
A torque limiter that is disposed in a gear train that drives the paper contact mechanism and transmits the power of the motor to the paper contact mechanism within a range restricted by the movement restriction mechanism;
A controller for controlling the motor to move the paper contact mechanism to the skew correction position and to rotate the paper position correction roller in the paper feed direction;
A sheet feeding device comprising: The sheet feeding device according to claim 1 , wherein the control device holds the state in which the sheet contact mechanism is moved to the skew correction position for a predetermined time. The movement limiting mechanism includes a sheet feeding apparatus according to claim 1 or 2, characterized in that a limiting mechanism for limiting the range of the rotational movement of the gear of the gear train for driving the paper contact mechanism. The paper position correction roller and the paper contact mechanism are configured such that a friction force acting between the paper and the paper position correction roller is larger than a friction force acting between the paper and the paper contact mechanism. The sheet feeding device according to any one of claims 1 to 3 , wherein the sheet feeding device is provided. The paper position correcting roller, the sheet contact mechanism is formed at a location in contact with the sheet feed according to any one of claims 1 to 4, characterized in that it comprises a contact roller that contacts with the sheet Paper device. Comprising a sheet detector for detecting the entry of the sheet, said control device according to any one of claims 1 to 5, characterized in that for controlling the device based on the sheet detection signal from the paper detecting device Paper feeder. The paper contact mechanism includes a drive shaft that is driven by a gear train, an arm portion that is rotatably attached to the drive shaft within a predetermined range, and a paper contact portion that is disposed at the tip of the arm portion. sheet feeding apparatus according to any one of claims 1 to 6, characterized in. The paper feeding device according to claim 7 , wherein the arm portion is urged by an elastic body in a paper pressing direction. The sheet contact portion, the sheet feed according to claim 7 or 8, wherein the sheet position correcting roller in skew correction position is shaped to contact the sheet at a position substantially the same position in contact with the sheet apparatus. Before SL for feeding the contact portion includes a sheet according to 7 or 8, characterized in that the said sheet position correcting roller in skew correction position is shaped to contact the paper at two places which sandwich the position in contact with the sheet Paper device. Before SL for paper contact portion, the sheet feeding apparatus according to claim 7 or 8, characterized in that it comprises a rotary member contacting freely to the paper rotation to the tip of the arm portion. The sheet feeding device according to claim 7, wherein the sheet contact portion is formed of an elastic member. A sheet feeding apparatus according to any one of claims 1 to 1 2,
An image forming unit that forms an image on a sheet carried from the sheet feeding device;
An image forming apparatus comprising:

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