Feeder equipped with actuator having reflective surface where space propagating energy reflects and pivotable by abutment against sheet being conveyed and image forming apparatus

A feeder includes a conveyance path, a conveyance roller that conveys a sheet along the conveyance path, a transmitter that emits a space propagating energy, a receiver that receives a reflected energy obtained by reflection of the space propagating energy, and an actuator mounted pivotably on a pivot shaft and including first and second legs extending in different directions from the pivot shaft. The first leg is disposed to extend to the conveyance path and abut against the sheet being conveyed along the conveyance path. The second leg has a reflective surface crossing a path of the space propagating energy. The actuator is pivoted by abutment of the sheet against the first leg. The reflective surface is formed so that the reflected energy obtained by the reflection of the space propagating energy on the reflective surface enters the receiver regardless of an angle of pivotal movement of the actuator.

INCORPORATION BY REFERENCE

This application claims priority to Japanese Patent Application No. 2021-173004 filed on 22 Oct. 2021, the entire contents of which are incorporated by reference herein.

BACKGROUND

The present disclosure relates to feeders and image forming apparatuses.

There is generally known a recording medium identifying device equipped with a medium sensor capable of detecting the amount of sag of a trailing end of a recording medium being conveyed by a sheet feed roller.

SUMMARY

A technique improved over the aforementioned technique is proposed as one aspect of the present disclosure.

A feeder according to an aspect of the present disclosure includes a conveyance path, a conveyance roller, a transmitter, a receiver, and an actuator. The conveyance roller conveys a sheet along the conveyance path. The transmitter emits a space propagating energy. The receiver receives a reflected energy obtained by reflection of the space propagating energy. The actuator is mounted pivotably on a pivot shaft and includes a first leg and a second leg extending in different directions from the pivot shaft. The first leg is disposed to extend to the conveyance path and abut against the sheet being conveyed along the conveyance path. The second leg has a reflective surface crossing a path of the space propagating energy. The actuator is pivoted by abutment of the sheet against the first leg. The reflective surface is formed so that the reflected energy obtained by the reflection of the space propagating energy on the reflective surface enters the receiver regardless of an angle of pivotal movement of the actuator.

DETAILED DESCRIPTION

Hereinafter, a description will be given of an embodiment of the present disclosure with reference to the drawings. Throughout the drawings, the same or corresponding parts are designated by the same references and further explanation thereof will be omitted. In this embodiment, the X axis, Y axis, and Z axis perpendicular to each other are shown in the drawings. The Z axis is parallel to the vertical plane. The X and Y axes are parallel to the horizontal plane.

In this embodiment, the direction of the Z axis which is the direction of conveyance of a sheet S in an image forming device14may be referred to as a main scanning direction. The direction of the Y axis may be referred to as a sub-scanning direction. The direction of the X axis may be referred to as a direction orthogonal to the main scanning direction and the sub-scanning direction.

With reference toFIGS.1to6, a description will be given of a multifunction peripheral1including a feeder100according to an embodiment of the present disclosure.FIG.1is a cross-sectional view showing the structure of the multifunction peripheral1.FIGS.2A and2Bare views showing an actuator21of the feeder100.FIGS.3A and3Bare views showing states of the feeder100where the actuator21is provided in a linear conveyance path31.FIGS.4A to4Care views showing states of the feeder100where the actuator21is provided in a curved conveyance path30.FIG.5is a graph showing a distance characteristic of the actuator21.FIGS.6A and6Bare graphs showing the X-angle characteristic and the Y-angle characteristic, respectively, of the actuator21.

Referring toFIG.1, the multifunction peripheral1is a multifunction printer (MFP) in which a scanner, a copier, a printer, a facsimile machine, and other functions are combined together. The multifunction peripheral1may be, for example, a copier, a facsimile machine or a multifunction peripheral combining these functions. As shown inFIG.1, the multifunction peripheral1includes a document reading device2and an image forming apparatus3.

The document reading device2includes a document feed device10and an image reading device11. The document feed device10includes, for example, a document tray, a document feed part, a document sensor, and a document discharge part. An example of the document feed device10is an ADF (auto document feeder).

The image reading device11includes an optical system. The optical system includes, for example, a light-emitting device, a lens, a reflecting mirror, and a light-receiving device. The image reading device11reads an image of an original document G being conveyed by the document feed device10. The image reading device11generates image data representing the read image. An example of the image reading device11is a CIS (contact image sensor) scanner or a CCD (charge coupled device) scanner.

In this embodiment, the image forming apparatus3is an electrophotographic printer. The image forming apparatus3includes a sheet feed device12, a sheet conveyance device13, an image forming device14, a fixing device15, a sheet ejection device16, and a control device17. The sheet feed device12and the sheet conveyance device13constitutes the feeder100. The sheet feed device12includes, for example, a sheet tray on which sheets S are to be placed, and a pick-up roller.

The sheet conveyance device13includes a conveyance path20, an actuator21, a conveyance roller22, a conveyance motor, a transmitter24, a receiver25, and an elastic member26. A sheet S is conveyed along the conveyance path20. The conveyance path20may include a linear conveyance path31as shown inFIGS.3A and3Band/or a curved conveyance path30as shown inFIGS.4A to4C. The curved conveyance path30is formed in a curved shape. In this embodiment, as shown inFIG.1, the conveyance path20partially consists of a curved conveyance path30and partially consists of a linear conveyance path31.

Next, a detailed description will be given of the actuator21. The actuator21is a detecting member for use in detecting the stiffness or thickness of a sheet S being conveyed through the conveyance path20. As shown inFIG.2A, the actuator21is mounted pivotably on a pivot shaft. The actuator21includes a first leg40and a second leg41extending in different directions from the pivot shaft. In the example shown inFIG.2A, the first leg40and the second leg41extend in directions 180 degrees opposite to each other from the pivot shaft.

The first leg40is disposed to extend to the conveyance path20and abut against the sheet S being conveyed along the conveyance path20. For example, as shown inFIG.3A, the first leg40extends to and abuts against the linear conveyance path31. As shown inFIGS.2B,3A, and3B, the actuator21is pivoted by abutment of the sheet S against the first leg40. By this pivotal movement, the actuator21mediates information for detecting the characteristic or type of the sheet S.

The second leg41crosses the path of a space propagating energy emitted from the transmitter24. Examples of the space propagating energy include light and ultrasound. As shown inFIG.2A, the second leg41has a reflective surface crossing the path of the space propagating energy. As shown inFIG.2B, the reflective surface is formed so that a reflected energy obtained by the reflection of the space propagating energy on the reflective surface enters the receiver25regardless of the angle of pivotal movement of the actuator21. The reflective surface may be formed so that the entire reflected energy enters the receiver25regardless of the angle of pivotal movement of the actuator21.

In the actuator21in this embodiment, the reflective surface may be formed into a curved surface where the incident angle of the space propagating energy on the reflective surface is identical with the reflection angle of the reflected energy from the reflective surface. Furthermore, in the actuator21in this embodiment, the curved surface of the reflective surface may include a partially cylindrical shape the center of which is a point of intersection between the path of the space propagating energy and the central axis of the second leg41extending from the pivot shaft. Thus, the reflected energy more certainly enters the receiver25regardless of the angle of pivotal movement.

As shown inFIG.3A, the conveyance roller22is disposed, for example, in the linear conveyance path31. The conveyance roller22conveys the sheet S along the conveyance path20. The conveyance motor drives the conveyance roller22into rotation. The transmitter24emits the space propagating energy. The receiver25receives the reflected energy obtained by the reflection of the space propagating energy on the reflective surface of the second leg41and outputs information on the received reflected energy.

Meanwhile, in the above-described general recording medium identifying device, vibrations of the recording medium during conveyance makes the distance between the medium sensor and the recording medium unstable, which presents a problem of reduced detection accuracy.

Unlike the above, in this embodiment, the actuator21has the above-described reflective surface and is pivoted by abutment against a sheet S being conveyed. which enables the measurement of the thickness or stiffness of the sheet S with stable accuracy based on the intensity of the reflected energy.

The transmitter24may be a light-emitting device that emits light. An example of the light-emitting device is an LED (light-emitting diode). The receiver25may be a light-receiving device that receives reflected light from the reflective surface and outputs information on the amount of reflected light as information on the received reflected energy. An example of the light-receiving device is a CCD (charge coupled device). The information on the amount of reflected light may include information showing whether the amount of reflected light is high or low.

In this embodiment, in a manner that the light-emitting device as the transmitter24and the light-receiving device as the receiver25emits and receives light, respectively, the distance D1or D2between the reflective surface of the second leg41and the receiver25can be measured with high accuracy.

Alternatively, the transmitter24may be an ultrasound transmitter. An example of the ultrasound transmitter is an electrostrictive vibrator constituted by lead zirconate titanate or the like vibrating upon application of AC voltage. The receiver25may be an ultrasound receiver. The ultrasound receiver receives reflected ultrasound from the reflective surface and outputs information on the amount of reflected ultrasound as information on the received reflected energy.

In this embodiment, in a manner that the ultrasound transmitter as the transmitter24and the ultrasound receiver as the receiver25emits and receives ultrasound, respectively, the distance D1or D2between the reflective surface of the second leg41and the receiver25can be measured with high accuracy.

For example, as shown inFIGS.4A to4C, when the actuator21is located laterally to the outer periphery of the curved conveyance path30, the first leg40is disposed to enter the curved conveyance path30from the outer periphery of the curved conveyance path30and abut against a sheet S being conveyed along the curved conveyance path30. The elastic member26urges the actuator21. The elastic member26urges the second leg41of the actuator21in a direction against the force of the conveyed sheet S pressing the first leg40of the actuator21. Alternatively, the elastic member26may be configured to urge the first leg40of the actuator21in a direction against the force of the conveyed sheet S pressing the first leg40of the actuator21. An example of the elastic member26is a spring.

Generally, a sheet S has a different thickness, stiffness or other characteristics depending on the type. When a sheet S having a large thickness and a large stiffness is conveyed along the curved conveyance path30having a large bending stress as shown inFIG.4A, the sheet S is conveyed while rubbing against the wall of the curved conveyance path30located outwardly in the direction of the curvature radius. Therefore, the first leg40of the actuator21receives a large pressing force from the sheet S. The elastic member26urges the second leg41against the pressing force of the sheet S applied to the first leg40.

Thus, when as shown inFIG.4Ba sheet S having a large stiffness (a sheet S having a large thickness) is conveyed to the actuator21, the second leg41of the actuator21moves a distance N1away from the transmitter24and the receiver25. The receiver25outputs information on the received reflected energy based on the intensity (for example, the amount of reflected ultrasound or the amount of reflected light) of the reflected energy.

On the other hand, when as shown inFIG.4Ca sheet having a small stiffness (a sheet S having a small thickness) is conveyed to the actuator21, the sheet S yields to the force of the elastic member26urging the actuator21. As a result, when the sheet S having a small stiffness is conveyed to the actuator21, the second leg41of the actuator21moves a distance N2away from the transmitter24and the receiver25. In this case, the distance N1is larger than the distance N2. The receiver25outputs information on the received reflected energy based on the intensity (for example, the amount of reflected ultrasound or the amount of reflected light) of the reflected energy.

In this embodiment, when the actuator21is disposed in the curved conveyance path30, the stiffness or thickness of the sheet S can be more suitably measured because the actuator21includes the elastic member26.

The image forming device14includes, for example, an image data input device, a charging device, an exposure device, a development device, a transfer device, and a cleaning device. The image forming device14forms a toner image on a sheet S based on image data.

The image forming apparatus3may be an inkjet printer. When the image forming apparatus3is an inkjet printer, the image forming device14includes at least an ink tank, an ink cartridge, and an ink head. The image forming device14forms an ink image on a sheet S based on image data. When the image forming apparatus3is an inkjet printer, the image forming apparatus3need not necessarily include the fixing device15.

The fixing device15applies heat and pressure to the toner image formed on the sheet S, thus fixing the toner image on the sheet S. The fixing device15includes, for example, a fixing belt, a pressure roller, and a heater.

The fixing belt is a hollow, cylindrical belt. The pressure roller is pressed against the fixing belt to form a nip with the fixing belt. When driven into rotation by a drive device, the pressure roller rotates the fixing belt.

The heater is supplied with electric power from a power source to apply heat to the fixing belt. The heater is disposed in proximity to the inner peripheral surface of the fixing belt. When passing through the nip, the sheet S being conveyed by the sheet conveyance device13is heated by the heater. As a result, the toner image is fixed on the sheet S.

The sheet ejection device16ejects the sheet S to the outside of the housing of the multifunction peripheral1. The sheet ejection device16includes an ejection roller and a sheet output tray18. The ejection roller ejects to the sheet output tray18the sheet S conveyed from the fixing device15by the conveyance roller22. Ejected sheets S are stacked on the sheet output tray18.

The control device17controls the components of the multifunction peripheral1or the image forming apparatus3. The control device17includes a processor. An example of the processor is a CPU (central processing unit). The control device17functions, through the processor executing a control program stored in a ROM (read only memory) or an HDD (hard disk drive), as a calculator60and a setter61. The calculator60and the setter61can be implemented, for example, by an ASIC (application specific integrated circuit).

The calculator60calculates the stiffness or thickness of a sheet S based on information on the amount of reflected light output by the light-receiving device serving as the receiver25. Alternatively, the calculator60calculates the stiffness or thickness of a sheet S based on information on the amount of reflected ultrasound output by the ultrasound receiver serving as the receiver25.

The setter61configures settings for the components of the image forming apparatus3equipped with the sheet conveyance device13, based on the stiffness or thickness of the sheet S calculated by the calculator60. For example, the setter61configures settings for the image forming device14based on the calculated stiffness or thickness of the sheet S.

In this embodiment, by calculating the stiffness or thickness of the sheet S, the settings for the components of the image forming apparatus3equipped with the sheet conveyance device13can be suitably configured.

Next, with reference toFIG.5, a description will be given of the distance characteristic between the reflective surface of the second leg41and the receiver25. InFIG.5, the horizontal axis indicates the distance between the reflective surface of the second leg41of the actuator21and the receiver25. The vertical axis indicates the output of the receiver25.

As shown inFIG.5, as the reflective surface of the second leg41approaches the receiver25, the output of the receiver25increases. As the reflective surface of the second leg41moves away from the receiver25, the output of the receiver25decreases. The distance characteristic of the reflective surface of the second leg41with the receiver25is a downward-sloping, approximately linear characteristic.

Next, with reference toFIGS.6A and6B, a description will be given of the angle characteristics representing the relationship between the tilt of the transmitter24and the output of the receiver25.FIGS.6A and6Bshow the X-angle characteristic and the Y-angle characteristic, respectively, of the receiver25when the position of the actuator21shown inFIG.2Ais fixed and the positions of the transmitter24and the receiver25are changed.

FIGS.6A and6Balso show how the transmitter24and the receiver25are mounted to a substrate. As shown inFIG.6A, when the transmitter24and the receiver25are in their horizontal positions in the X direction (the positions where their angles in the X direction are zero degrees), the X-angle characteristic of the receiver25exhibits a highest value. When the transmitter24and the receiver25tilt in the X direction (to the right or left of the plane of the figure), the output of the receiver25decreases.

On the other hand, when as shown inFIG.6Bthe transmitter24and the receiver25tilt toward one side in the Y direction (the front of the plane of the figure), the output of the receiver25increases. When the transmitter24and the receiver25tilt toward the other side in the Y direction (the back of the plane of the figure), the output of the receiver25decreases.

As shown inFIGS.6A and6B, when the transmitter24and the receiver25are in their horizontal positions in the X direction (the right and left direction of the plane of the figure), i.e., their angles in the X direction are zero degrees, and the transmitter24and the receiver25are in their horizontal positions in the Y direction (the front and back direction of the plane of the figure), i.e., their angles in the Y direction are zero degrees, the X-angle characteristic and Y-angle characteristic of the receiver25exhibit respective highest values.

Therefore, when, with the transmitter24and the receiver25in the fixed positions, the reflective surface of the second leg41changes to keep a position where the angle in the X direction and the angle in the Y direction are zero degrees with respect to the transmitter24and the receiver25, the receiver25exhibits the distance characteristic shown inFIG.5.

The above description has been given of an embodiment of the present disclosure with reference to the drawings. However, the present disclosure is not limited to the above embodiment and can be implemented in various forms without departing from the gist of the invention. For the sake of ease of understanding, the drawings are schematically given by mainly showing components. The number of components and so on shown in the drawings are different from those of actual components for convenience of creation of the drawings. The components described in the above embodiment are merely illustrative, not particularly limited, and can be changed variously without substantially departing from the effects of the present disclosure.

INDUSTRIAL APPLICABILITY

The present disclosure is applicable to the field of feeders.