JP6957985B2 - Sheet transfer device and image forming device - Google Patents

Description

The present invention relates to a sheet transfer device and an image forming device capable of detecting the sheet loading height on a pressure plate.

Conventionally, a sheet transport device having a structure in which a pressure plate that supports a seat and can be raised and lowered is lifted by a motor to lift the seat to a supplyable position in contact with a supply roller and a separation roller, and the pressure plate is lifted from the lowest position. There is known a sheet transfer device that calculates the number of sheets supported on a pressure plate, that is, the remaining amount of sheets, based on the driving time and the amount of rotation of the motor required to rise to the supplyable position.

In such a seat transfer device, the driving force is transmitted from the motor to the pressure plate by a driving mechanism having a plurality of gears. Since there is some play, the time from when the motor starts to drive until the pressure plate actually starts to rise and the amount of rotation of the motor vary. This variation in time and rotation amount causes an error in calculating the number of sheets supported on the pressure plate.

Therefore, as disclosed in Patent Document 1, the pressure plate detects that the push-up plate, which is a member for raising the pressure plate, has started to operate, and the pressure plate starts to operate from the time when the sensor detects the start of operation of the push-up plate. A configuration has been devised in which the drive time and the amount of rotation of the motor from the lowest position to the supplyable position are measured, and the number of sheets is calculated based on the measured values.

In this way, by calculating the number of sheets based on the drive time and rotation amount of the motor after the push-up plate for raising the pressure plate starts operation, the push-up plate starts operation from the start of drive of the motor. It is possible to eliminate variations in the driving time and rotation amount of the motor that occur up to this point, and it is possible to reduce the error in the calculated number of sheets.

Japanese Unexamined Patent Publication No. 2015-202954

However, in the sheet transport device disclosed in Patent Document 1, although it is possible to reduce the error in the calculated number of sheets, for example, the pressure plate does not rise normally when the push-up plate operates. When a failure occurred in the mechanism for moving the push-up plate or the pressure plate, the failure could not be detected.

Therefore, there is a demand for a sheet transfer device and an image forming device that can detect whether or not a failure has occurred in the push-up plate or the mechanism for moving the pressure plate when calculating the number of sheets on the pressure plate.

The sheet transfer device and the image forming device that solve the above problems have the following features.
That is, the sheet transfer device is provided in the first housing for accommodating the sheet and the first housing, supports the sheet, and is at the lowest position, which is the first position and above the first position. A pressure plate made of a conductor, which is configured to be movable between a second position to be a position, and a pressure plate provided in the first housing and constantly in contact with the pressure plate are moved to the first position and the first position. A conductor push-up plate to be moved between the two positions and a first end provided in the first housing are separated from the pressure plate when the pressure plate is in the first position, and the pressure plate is separated from the pressure plate. A first elastic member made of a conductor, which comes into contact with the pressure plate when moving from the first position toward the second position and whose second end projects out of the first housing, and the first elastic member. A second elastic member made of a conductor, which is provided in the housing, the first end of which follows the displacement of the push-up plate and comes into contact with the push-up plate, and the second end projects out of the first housing. A sheet cassette having a The first electrode that contacts the second end of the first elastic member when it is housed in the section, and the sheet cassette house that is provided in the sheet cassette house and is housed in the sheet cassette house. A second electrode in contact with the second end of the second elastic member, a sheet transporting portion provided in the second housing and transporting the sheet, and a sheet transporting portion provided in the second housing to supply a driving force. A drive unit having a motor and a transmission mechanism for transmitting a driving force output by the motor to the push-up plate when the seat cassette is housed in the seat cassette storage unit, and a drive unit that displaces the push-up plate. A sheet sensor that detects that the sheet connected to the first electrode and supported by the pressure plate has reached a predetermined position by moving upward of the pressure plate, and emits light when supplied with electric power. A light emitting element that is a light source, a light receiving element that receives and detects light emitted from the light emitting element, and an actuator that displaces in contact with the sheet. When the light emitting element comes into contact with the sheet, the light emitting element and the light receiving element An actuator that is located between the light emitting element and blocks the light emitted from the light emitting element, and is not located between the light emitting element and the light receiving element and does not block the light emitted from the light emitting element when it does not come into contact with the sheet. When the light emitting element is supplied with electric power and the actu When the user is not located between the light emitting element and the light receiving element, the light receiving element outputs a first signal, the light emitting element is supplied with electric power, and the actuator emits light. A sheet in which the light receiving element outputs a second signal when it is located between the element and the light receiving element, and the light receiving element outputs the second signal when the light emitting element is not supplied with power. A power supply circuit that supplies power to the light emitting element of the sheet sensor, the sensor, the control unit, and the first electrode by separating the pressure plate and the first end of the first elastic member. When the supply command is received from the control unit when the second electrode is not electrically connected, power is supplied to the light emitting element and the supply command is not received from the control unit. Is when the first electrode and the second electrode are electrically connected by contacting the pressure plate and the first end of the first elastic member without supplying power to the light emitting element. Is a sheet transfer device including a power supply circuit that supplies power to the light emitting element, and the control unit can receive the first signal and the second signal, and the power supply circuit can receive the first signal and the second signal. The supply command can be transmitted, and the supply command is transmitted to the power supply circuit before the push-up plate is displaced and the pressure plate is moved upward by controlling the drive unit. When the first signal is received from the seat sensor, and when the transmission of the supply command is stopped and the drive unit is controlled to move the pressing plate upward, the power supply circuit is reached. If the first signal is not received from the seat sensor even after a predetermined time has elapsed from the time when the transmission of the supply command is stopped, a failure is notified.

Further, the sheet transfer device is provided in the first housing for accommodating the sheet and the first housing, supports the sheet, and is at the lowest position, which is the first position and above the first position. A pressure plate made of a conductor, which is configured to be movable between a second position to be a position, and a pressure plate provided in the first housing and constantly in contact with the pressure plate are moved to the first position and the first position. A conductor push-up plate to be moved between two positions and a first end provided in the first housing are separated from the pressure plate when the pressure plate is in the first position, and the pressure plate is separated from the pressure plate. A first elastic member made of a conductor, which comes into contact with the pressure plate when moving from the first position toward the second position and whose second end projects out of the first housing, and the first elastic member. A second elastic member made of a conductor, which is provided in the housing, the first end of which follows the displacement of the push-up plate and comes into contact with the push-up plate, and the second end projects out of the first housing. A sheet cassette having a The first electrode that contacts the second end of the first elastic member when it is housed in the section, and the sheet cassette house that is provided in the sheet cassette house and is housed in the sheet cassette house. A second electrode in contact with the second end of the second elastic member, a sheet transporting portion provided in the second housing and transporting the sheet, and a sheet transporting portion provided in the second housing to supply a driving force. A drive unit having a motor and a transmission mechanism for transmitting a driving force output by the motor to the push-up plate when the seat cassette is housed in the seat cassette storage unit, and a drive unit that displaces the push-up plate. A sheet sensor that detects that the sheet connected to the first electrode and supported by the pressure plate has reached a predetermined position by moving upward of the pressure plate, and emits light when supplied with electric power. A light emitting element that is a light source, a light receiving element that receives and detects light emitted from the light emitting element, and an actuator that displaces in contact with the sheet. When the light emitting element comes into contact with the sheet, the light emitting element and the light receiving element An actuator that is located between the light emitting element and blocks the light emitted from the light emitting element, and is not located between the light emitting element and the light receiving element and does not block the light emitted from the light emitting element when it does not come into contact with the sheet. When the light emitting element is supplied with electric power and the actu When the user is not located between the light emitting element and the light receiving element, the light receiving element outputs a first signal, the light emitting element is supplied with power, and the actuator emits light. A sheet in which the light receiving element outputs a second signal when it is located between the element and the light receiving element, and the light receiving element outputs the second signal when the light emitting element is not supplied with power. A power supply circuit that supplies power to the sensor, a clock pulse signal output unit that outputs a clock pulse signal at a fixed cycle, a control unit, and the light emitting element of the seat sensor, and can receive the clock pulse signal. The clock pulse signal is received when the first electrode and the second electrode are not electrically connected by separating the pressure plate and the first end of the first elastic member. In this case, power is supplied to the light emitting element in synchronization with the clock pulse signal to cause the light emitting element to emit light intermittently, and when the clock pulse signal is not received, power is supplied to the light emitting element. Instead, when the first electrode and the second electrode are electrically connected by contacting the pressure plate and the first end of the first elastic member, power is supplied to the light emitting element. A sheet transfer device including a power supply circuit, wherein the control unit can receive the first signal and the second signal, and the push-up plate is displaced by controlling the drive unit. This is a case where the first signal is intermittently received from the seat sensor in response to the clock pulse signal received by the power supply circuit before the pressure plate is moved upward, and the drive unit is moved to the drive unit. When the pressing plate is controlled to move upward, the first signal is not continuously received from the seat sensor even after a predetermined time has elapsed from the time when the pressing plate starts moving upward. , Notify the failure.

According to the present invention, before calculating the number of sheets S based on the amount of movement of the pressure plate 12 upward, whether or not a failure has occurred in the mechanism for moving the push-up plate or the pressure plate when calculating the number of sheets. It becomes possible to detect.

It is a central sectional view which shows the image forming apparatus. It is a top view which shows the sheet cassette. It is a side sectional view which shows the contact part between a pressure plate and a push-up plate. (A) is a side sectional view showing an image forming apparatus in a state where the pressure plate supporting the seat is in the lowest position, and (b) is a side sectional view showing the pressure plate supporting the seat moving upward and the sheet sensor coming into contact with the seat. It is a side sectional view which shows the image forming apparatus of the state, (c) is the side sectional view which shows the image forming apparatus in the state which the pressure plate supporting a sheet moves upward, and the sheet is in contact with a pickup roller. (A) is a side sectional view showing an image forming apparatus in a state where the pressure plate on which the sheet is not placed is in the lowest position, and (b) is an upper side of the pressure plate on which the sheet is not placed up to the position of the sheet sensor. It is a side sectional view showing the image forming apparatus in the state which moved to, and (c) is the side sectional view which shows the image forming apparatus in a state where a pressure plate on which a sheet is not placed moves upward and is in contact with a pickup roller. be. It is a block diagram which shows the control part, the motor connected to the control part, a seat sensor, a cassette sensor, and a pulse signal output part. It is a side sectional view which shows the seat cassette in the accommodation position. It is a front sectional view which shows the seat cassette in the accommodation position. It is a side sectional view which shows the contact part between a pressure plate and a 1st elastic member, (a) is a figure which shows the state which the edge part of a pressure plate and the 1st end of a 1st elastic member are separated, (b). Is a diagram showing a state in which the edge portion of the pressure plate and the first end of the first elastic member are in contact with each other. It is a side sectional view which shows the sheet cassette in a separated position. It is a circuit diagram which shows the sensor board and the power supply circuit on which the detector of a sheet sensor is mounted. It is a figure which shows the flowchart of the steps S101 to S133 of the update process of the number of sheets at the time of inserting a sheet cassette. It is a figure which shows the flowchart of the step S135-S149 of the update process of the number of sheets at the time of inserting a sheet cassette. It is a figure which shows the timing chart of the seat sensor output, etc. in the seat cassette in the 1st state. It is a figure which shows the timing chart of the seat sensor output, etc. in the seat cassette in the 2nd state. It is a figure which shows the timing chart of the seat sensor output, etc. in the seat cassette in the 3rd state. It is a figure which shows the flow of the calculation process of the number of sheets. It is a figure which shows the relationship between the value of a counter, and the seat loading height. It is a figure which shows the timing chart of the signal output by a seat sensor. It is a figure which shows the flowchart of steps S201-S239 of the sheet number update process at the time of power-on. It is a figure which shows the flowchart of steps S241-S255 of the sheet number update process at the time of power-on. It is a figure which shows the timing chart of the seat sensor output, etc. in the seat cassette in the 4th state. It is a figure which shows the timing chart of the seat sensor output, etc. in the seat cassette in the 5th state. It is a circuit diagram which shows the sensor board and the power supply circuit which concerns on 2nd Embodiment. It is a figure which shows the timing chart of the seat sensor output and the like in the seat cassette in the 1st state which concerns on 2nd Embodiment. It is a figure which shows the flowchart of steps S101 to S133 of the sheet number update processing at the time of inserting the sheet cassette which concerns on 2nd Embodiment. It is a figure which shows the flowchart of steps S201-S239 of the sheet number update process at the time of power-on which concerns on 2nd Embodiment.

Next, a mode for carrying out the present invention will be described with reference to the accompanying drawings.

[Overall configuration of image forming apparatus]
The image forming apparatus 1 shown in FIG. 1 is an embodiment of an image forming apparatus including the sheet conveying device according to the present invention, and includes a main body housing 2, a supply unit 3 having a sheet cassette 10 and a sheet conveying section 20. A drive unit provided in the main body housing 2 and having a seat cassette accommodating portion 2a for accommodating the seat cassette 10, an image forming unit 5, a motor 40 for supplying the driving force, and a transmission mechanism 41 for transmitting the driving force of the motor 40. 4 (see FIG. 2) and a control unit 6 (see FIG. 6) are provided. The seat transfer device includes a main body housing 2, a sheet cassette 10, a sheet transfer unit 20, a sheet cassette accommodating unit 2a, a drive unit 4, a control unit 6, and the like.

In the following description, the "left side", "right side", "front side of the paper surface", and "back side of the paper surface" in FIG. 1 are referred to as "rear side", "front side", and "right side" of the image forming apparatus 1, respectively. And "left side". Further, the "upper side" and "lower side" in FIG. 1 are defined as "upper side" and "lower side" of the image forming apparatus 1, respectively.

The main body housing 2 is a box body formed in a substantially rectangular parallelepiped shape, and houses a supply unit 3, an image forming unit 5, a driving unit 4, and a control unit 6. The lower part of the main body housing 2 is configured as a seat cassette accommodating portion 2a for accommodating the seat cassette 10 in a detachable manner. The main body housing 2 is an example of a second housing.

The supply unit 3 is arranged below the image forming apparatus 1, and conveys the sheet 18 housed in the sheet cassette 10 to the image forming unit 5 by the sheet conveying unit 20.

The seat cassette 10 has a storage position in which the seat cassette 10 is stored in a predetermined position of the sheet cassette storage portion 2a and a separation position in which the seat cassette 10 is separated from the seat cassette storage portion 2a and is not stored in the seat cassette storage portion 2a. It is configured to be displaceable between. The seat cassette 10 in the accommodation position is displaced to the separation position by moving forward, and the seat cassette 10 in the separation position is displaced to the accommodation position by moving backward.
Further, the supply unit 3 includes a cassette sensor 93 (see FIG. 6) that detects whether or not the seat cassette 10 is accommodated in the seat cassette accommodating portion 2a.

As shown in FIGS. 1 and 2, the seat cassette 10 is arranged in a cassette main body 11 that houses the seat 18 and in the cassette main body 11, supports the seat 18, and has a first position that is the lowest position and the above. The pressure plate 12 is movable between the pressure plate 12 and the second position, which is located above the first position, and the pressure plate 12 is arranged below the pressure plate 12 in the cassette body 11 and is always in contact with the pressure plate 12. Has a push-up plate 13 for moving between the first position and the second position. The cassette body 11 is an example of the first housing.

The pressure plate 12 is rotatably supported by the cassette body 11 around a rotation fulcrum 12a at the rear end, and by rotating around the rotation fulcrum 12a, the front end of the pressure plate 12 is moved in the vertical direction. It is possible to move to.

The push-up plate 13 is rotatably supported by the cassette body 11 about the rotation fulcrum 13a at the rear end, and by rotating around the rotation fulcrum 13a, the pressure plate 12 is set to the first position. It is possible to move it to and from the second position. In the push-up plate 13, the front end portion is a contact portion 13b that contacts the lower surface of the pressure plate 12. The push-up plate 13 is driven by a driving force from the motor 40.
The pressure plate 12 and the push-up plate 13 are formed of a galvanized steel plate. The pressure plate 12 and the push-up plate 13 do not necessarily have to be made of a galvanized steel plate, and may be formed of a conductor such as another metal or a conductive resin.

The transmission mechanism 41 is a mechanism for transmitting the driving force from the motor 40 to the push-up plate 13, and is arranged on the outer surface 11a on the left and right sides of the cassette body 11 as shown in FIG.
The transmission mechanism 41 includes a pressure plate moving gear 411 that meshes with the pressure plate driving gear 42 connected to the motor 40, a gear 412a that is arranged downstream in the driving force transmission direction of the pressure plate moving gear 411 and meshes with the pressure plate moving gear 411, and a gear 412a. It includes a gear 412b that is arranged coaxially with the gear 412a and rotates integrally with the gear 412a, and a gear 413 that is arranged on the downstream side in the driving force transmission direction of the gear 412b and meshes with the gear 412b. The gear 413 is connected to the push-up plate 13.

The driving force from the motor 40 is input to the pressure plate moving gear 411 via the pressure plate driving gear 42, and the driving force input to the pressure plate driving gear 42 is transmitted to the push-up plate 13 via the gears 412a, 412b and 413. And drives the pressing plate 13.

When the push-up plate 13 is driven by the motor 40 and rotates upward while the pressure plate 12 is in the first position, the push-up plate 13 pushes the pressure plate 12 while maintaining a state in which the contact portion 13b and the lower surface of the pressure plate 12 are in contact with each other. Move it upwards. The pressure plate 12 at the lowest position is moved upward by the push-up plate 13 to a position where the sheet 18 supported on the pressure plate 12 can be fed (state shown in FIG. 1).

As shown in FIG. 3, the push-up plate 13 is always in contact with the pressure plate 12 regardless of the rotation position of the pressure plate 12, and the push-up plate 13 and the pressure plate 12 are electrically connected to each other. Conductive grease 121 is applied to the portion where the push-up plate 13 comes into contact. That is, the lower surface of the pressure plate 12 is coated with the conductive grease 121, and the contact portion 13b of the push-up plate 13 is in contact with the portion of the pressure plate 12 to which the conductive grease 121 is applied.
In this way, by applying the conductive grease 121 to the portion of the pressure plate 12 in contact with the push-up plate 13, it is possible to stably and electrically connect the pressure plate 12 and the push-up plate 13.

The pressure plate drive gear 42 is provided in the main body housing 2, and when the seat cassette 10 is in the accommodation position, the pressure plate drive gear 42 and the pressure plate moving gear 411 of the transmission mechanism 41 mesh with each other to drive a driving force from the motor 40. Is configured to be input to the transmission mechanism 41.
On the other hand, when the seat cassette 10 is in the separated position, the pressure plate driving gear 42 and the pressure plate moving gear 411 are separated so that the driving force from the motor 40 is not input to the transmission mechanism 41.

When the seat cassette 10 is in the accommodation position, after the pressure plate 12 in the first position is moved upward to the second position by the push-up plate 13, reverse rotation prevention provided between the motor 40 and the pressure plate drive gear 42. Since the mechanism prevents the pressure plate drive gear 42 from rotating in the reverse direction, the pressure plate 12 is held in the second position even if the rotation of the motor 40 is stopped.
On the other hand, when the seat cassette 10 in the accommodating position is displaced to the separated position while the pressure plate 12 is moved upward to the second position by the push-up plate 13, the engagement between the pressure plate drive gear 42 and the pressure plate moving gear 411 is released. Therefore, the pressure plate 12 descends to the first position, which is the lowest position.

The sheet transport unit 20 is a mechanism for separating and taking out the sheets 18 held in the sheet cassette 10 one by one and transporting them toward the image forming unit 5. The pickup roller 21, the separation roller 22, the separation pad 23, and the transfer. A roller 24a and a resist roller 25 are provided.

The pickup roller 21 is a roller for taking out the sheet 18 which has been moved upward by the pressure plate 12 to the position where the paper can be fed, and is arranged above the front end portion of the pressure plate 12. When the sheet 18 placed on the pressure plate 12 is moved upward to the position where it can be fed, the upper end thereof is pressed against the pickup roller 21 with an appropriate pressure so that the sheet 18 can be fed.

When the sheet 18 is supported on the pressure plate 12, the pressure plate 12 moved upward by the push-up plate 13 moves upward to a position where the upper end of the supported sheet 18 is in pressure contact with the pickup roller 21. , The movement to the upper side is stopped.

Further, the pressure plate 12 is configured so that when the sheet 18 is not supported on the pressure plate 12, the upward movement is stopped when the uppermost position in the movable range in the vertical direction is reached. In this case, the uppermost position of the pressure plate 12 in the vertical movable range is set to, for example, a position where the pressure plate 12 comes into pressure contact with the pickup roller 21.

The separation roller 22 is arranged on the downstream side of the seat 18 in the transport direction with respect to the pickup roller 21, and the separation pad 23 is arranged to face the separation roller 22 and is urged toward the separation roller 22.
The sheet 18 taken out by the pickup roller 21 is sent out to the separation roller 22 side, separated one by one between the separation roller 22 and the separation pad 23, and is conveyed toward the transfer roller 24a.

The transfer roller 24a is a roller that applies a transfer force to the sheet 18, and is arranged on the downstream side of the sheet 18 in the transfer direction with respect to the separation roller 22. A paper dust removing roller 24b is arranged at a position facing the transport roller 24a. The sheet 18 transported toward the transport roller 24a is sandwiched between the transport roller 24a and the paper dust removing roller 24b, and is transported toward the resist roller 25.

The resist roller 25 is arranged on the downstream side of the sheet 18 in the transport direction with respect to the transfer roller 24a, and restricts the movement of the tip of the sheet 18 to be conveyed with the resist roller 26 arranged to face the resist roller 25. Then, after stopping once, the transfer is carried out toward the transfer position at a predetermined timing.

The image forming unit 5 is arranged on the downstream side of the sheet 18 in the transport direction with respect to the supply unit 3, and forms an image on the sheet 18 transported from the supply unit 3.
The image forming unit 5 is composed of a process cartridge 50 that transfers an image to the surface of the sheet 18 conveyed from the supply unit 3, an exposure unit 60 that exposes the surface of the photoconductor drum 54 of the process cartridge 50, and the process cartridge 50. It includes a fixing unit 70 for fixing the image transferred to the sheet 18.

The process cartridge 50 is arranged above the sheet cassette accommodating portion 2a in the main body housing 2, and includes a developer accommodating chamber 51, a supply roller 52, a developing roller 53, a photoconductor drum 54, and a transfer roller 55. And so on.

The exposure unit 60 includes a laser diode, a polygon mirror, a lens, a reflector, and the like, and by irradiating the photoconductor drum 54 with a laser beam based on the image data input to the image forming apparatus 1, the exposure unit 60 is provided. The surface of the photoconductor drum 54 is exposed.

Toner serving as a developer is stored in the developer storage chamber 51. The toner stored in the developer storage chamber 51 is sent to the supply roller 52 while being stirred by a stirring member (not shown). The supply roller 52 further supplies the toner sent from the developer accommodating chamber 51 to the developing roller 53.

The developing roller 53 is arranged in close contact with the supply roller 52, and carries toner supplied from the supply roller 52 and positively charged by a sliding contact member (not shown). Further, a positive development bias is applied to the developing roller 53 by a bias applying means (not shown).

The photoconductor drum 54 is arranged adjacent to the developing roller 53. The surface of the photoconductor drum 54 is uniformly positively charged by a charger (not shown) and then exposed by the exposure unit 60. The exposed portion of the photoconductor drum 54 has a lower potential than the other portions, and an electrostatic latent image based on the image data is formed on the photoconductor drum 54.
Then, a positively charged toner is supplied from the developing roller 53 to the surface of the photoconductor drum 54 on which the electrostatic latent image is formed, so that the electrostatic latent image is visualized and becomes a developer image. ..

The transfer roller 55 is arranged to face the photoconductor drum 54, and a negative transfer bias is applied by a bias applying means (not shown). With the transfer bias applied to the surface of the transfer roller 55, the sheet 18 is conveyed between the photoconductor drum 54 on which the developer image is formed and the transfer roller 55 (transfer position) without sandwiching the sheet 18. The developer image formed on the surface of the photoconductor drum 54 is transferred to the surface of the sheet 18.

The fixing unit 70 includes a heating roller 71 and a pressing roller 72. The heating roller 71 is rotationally driven by a driving force from the motor 40, and the heating roller 71 is heated by supplying electric power from a power source (not shown). The pressing roller 72 is arranged to face the heating roller 71, and is brought into close contact with the heating roller 71 to rotate in a driven manner. When the sheet 18 on which the developer image is transferred is conveyed to the fixing unit 70, the sheet 18 is conveyed while being sandwiched between the heating roller 71 and the pressing roller 72, and the developer image is fixed on the sheet 18.

The discharge unit 8 is arranged on the downstream side of the sheet 18 in the transport direction with respect to the image forming unit 5, and discharges the sheet 18 on which the image is formed by the image forming unit 5 to the outside of the main body housing 2. The discharge unit 8 includes a discharge roller 81 and a discharge tray 82. The discharge rollers 81 are a pair of rollers, and discharge the sheet 18 conveyed from the fixing unit 70 toward the outside of the main body housing 2. The discharge tray 82 is formed on the upper surface of the main body housing 2, and the sheet 18 discharged to the outside of the main body housing 2 is deposited on the discharge tray 82 by the discharge roller 81.

Further, the image forming apparatus 1 comes into contact with the sheet 18 supported by the pressure plate 12 when the pressure plate 12 is moved upward from the first position, and the sheet 18 moves in a predetermined manner by moving the pressure plate 12 upward. The seat sensor 9 for detecting that the vehicle has reached the position is provided.
As shown in FIGS. 4 and 11, the seat sensor 9 is a sensor including a contactor 91, a detector 92, and an actuator 93. The contactor 91 is configured to be rotatable around the rotation center 91a, and is configured to rotate in contact with the sheet 18 supported on the pressure plate 12 when the pressure plate 12 is moved upward. Has been done.

The detector 92 is a photo interrupter having a light emitting unit 92a composed of a light emitting element which is a light source that emits light when supplied with electric power, and a light receiving unit 92b composed of a light receiving element that receives and detects light emitted from the light emitting unit 92a. Is.
The actuator 93 can rotate integrally with the contactor 91 about the rotation shaft 91a, and by rotating around the rotation shaft 91a, it is interposed between the light emitting portion 92a and the light receiving portion 92b. It is configured to be displaceable to a position and a position not intervening between the light emitting unit 92a and the light receiving unit 92b.

When the contact 91 is not in contact with the sheet 18 supported on the pressure plate 12, the actuator 93 is displaced to a position where it does not intervene between the light emitting portion 92a and the light receiving portion 92b, and the contact 91 is displaced on the pressure plate 12. When it rotates in contact with the sheet 18 supported by the light emitting portion 92a, it is displaced to a position interposed between the light emitting portion 92a and the light receiving portion 92b.

When the actuator 93 is in a position not intervening between the light emitting unit 92a and the light receiving unit 92b, the light emitted from the light emitting unit 92a is received by the light receiving unit 92b, and the sheet sensor 9 is supported on the pressure plate 12. 18 is not detected.
When the actuator 93 is located between the light emitting unit 92a and the light receiving unit 92b, the light emitted from the light emitting unit 92a is blocked by the actuator 93, and the light emitted from the light emitting unit 92a is not received by the light receiving unit 92b. .. In this case, the seat sensor 9 detects the seat 18 supported on the pressure plate 12.

That is, the actuator 93 is displaced by coming into contact with the sheet 18, and when it comes into contact with the sheet 18, it is located between the light emitting unit 92a and the light receiving unit 92b to block the light emitted from the light emitting unit 92a and comes into contact with the sheet 18. When not, it is not located between the light emitting unit 92a and the light receiving unit 92b and does not block the light emitted from the light emitting unit 92a.

With such a configuration, the seat sensor 9 can detect the seat 18 when the pressure plate 12 is moved upward.
Specifically, for example, as shown in FIG. 4A, when the pressure plate 12 is located at the first position, the actuator 91 does not come into contact with the sheet 18 supported on the pressure plate 12 and does not rotate. Therefore, the actuator 93 is displaced to a position where it does not intervene between the light emitting unit 92a and the light receiving unit 92b. Therefore, the light emitted from the light emitting unit 92a is received by the light receiving unit 92b, and the seat sensor 9 does not detect the sheet 18.

On the other hand, as shown in FIG. 4B, when the pressure plate 12 moves upward from the first position and the actuator 91 comes into contact with the sheet 18, the actuator 91 rotates about the rotation center 91a. The actuator 93 is displaced to a position interposed between the light emitting unit 92a and the light receiving unit 92b. Therefore, the light emitted from the light emitting unit 92a is blocked by the actuator 93 and is not received by the light receiving unit 92b, and the seat 18 is detected by the seat sensor 9.

Further, when the pressure plate 12 is moved upward by the driving force from the motor 40 via the push-up plate 13, the upward movement of the pressure plate 12 is continued even after the contactor 91 comes into contact with the sheet 18. As shown in FIG. 4C, when the pressure plate 12 is moved upward after the contact 91 comes into contact with the sheet 18, the upper end of the sheet 18 supported on the pressure plate 12 comes into contact with the pickup roller 21. The pickup roller 21 is configured to be movable up and down, and is pushed upward by the sheet 18 in contact with the pickup roller 21.

When the pickup roller 21 is pushed up by the seat 18, the transmission of the driving force from the motor 40 to the push-up plate 13 is disengaged by the clutch, and the upward movement of the pressure plate 12 is stopped. The position at which the upward movement of the pressure plate 12 is stopped is the position where the upper end of the sheet 18 is in pressure contact with the pickup roller 21 so that the paper can be fed.

In the image forming apparatus 1, the pressure plate 12 at the first position is housed in the sheet cassette 10 based on the amount of movement of the pressure plate 12 upward when the sheet sensor 9 moves upward to the position where the sheet 18 is detected. It is configured to calculate the number of sheets 18 that are made. In this case, the amount of movement of the pressure plate 12 upward is calculated based on, for example, the rotation speed of the motor 40.

On the other hand, in the state where the seat 18 is not placed on the pressure plate 12, the seat sensor 9 detects the seat 18 because the contact 91 does not rotate even if the pressure plate 12 moves upward to the position of the contact 91. Is configured not to do.

Specifically, as shown in FIG. 2, a hole 99 penetrating the pressure plate 12 is formed in the pressure plate 12. The position of the hole 99 in the pressure plate 12 is a position where the contactor 91 enters the hole 99 and does not rotate even if the pressure plate 12 moves upward when the sheet 18 is not placed on the pressure plate 12. In the state where the sheet 18 is placed on the pressure plate 12, the hole 99 is covered by the sheet 18, and when the pressure plate 12 moves upward, the contact 91 comes into contact with the sheet 18 and rotates.

For example, as shown in FIG. 5A, when the pressure plate 12 on which the sheet 18 is not placed is located at the first position, the contactor 91 does not contact the pressure plate 12 and does not rotate, so that the actuator 93 Is displaced to a position where it does not intervene between the light emitting unit 92a and the light receiving unit 92b. In this case, since the light emitted from the light emitting unit 92a is received by the light receiving unit 92b, the seat sensor 9 does not detect the sheet 18.

Further, when the pressure plate 12 on which the sheet 18 is not placed is moved upward to the position shown in FIG. 5B, one end of the pressure plate 12 is located higher than the lower end of the contactor 91. However, the contact 91 does not rotate because it is in a state of being inserted into the hole 99 formed in the pressure plate 12. Therefore, the actuator 93 is located at a position not intervening between the light emitting unit 92a and the light receiving unit 92b, and the light emitted from the light emitting unit 92a is received by the light receiving unit 92b, so that the sheet sensor 9 does not detect the sheet 18.

When the pressure plate 12 moved upward to the position shown in FIG. 5 (b) is further moved upward, it comes into contact with the pickup roller 21 as shown in FIG. 5 (c). The pressure plate 12 in contact with the pickup roller 21 pushes up the pickup roller 21.
When the pickup roller 21 is pushed up by the pressure plate 12, the transmission of the driving force from the motor 40 to the push-up plate 13 is disengaged by the clutch, and the movement of the pressure plate 12 to the upper side is stopped. The moving position of the pressure plate 12 when the movement of the pressure plate 12 to the upper side is stopped is the highest position in the movable range of the pressure plate 12.

In this way, the sheet 18 is placed on the pressure plate 12 by forming a hole 99 in the pressure plate 12 and detecting by the detector 92 whether or not the contactor 91 is rotating when the pressure plate 12 is moved upward. It is possible to determine whether or not it is mounted.

The control unit 6 controls the operation of the motor 40 and measures the amount of rotation such as the number of rotations of the motor 40 when the pressure plate 12 is moved upward via the push-up plate 13 by the driving force from the motor 40. The number of sheets 18 accommodated in the sheet cassette 10 is calculated based on the measured rotation amount, and is provided in the main body housing 2.

As shown in FIG. 6, a motor 40, a seat sensor 9, and a cassette sensor 93 are connected to the control unit 6. Further, the image forming apparatus 1 includes a rotation pulse signal output unit 95 that outputs a rotation pulse signal indicating the rotation speed of the motor 40, and the rotation pulse signal output unit 95 is connected to the control unit 6.

The seat sensor 9 outputs a first signal when the light receiving unit 92b receives the light emitted from the light emitting unit 92a, and outputs a second signal when the light receiving unit 92b does not receive the light emitted from the light emitting unit 92a. ..
The control unit 6 is configured to be able to receive the first signal and the second signal output from the seat sensor 9 and the rotation pulse signal output from the rotation pulse signal output unit 95.

[First Embodiment of the configuration for calculating the number of sheets S]
Next, a first embodiment of the configuration for calculating the number of sheets S in the sheet transport device will be described.
As shown in FIGS. 2, 7, and 8, the sheet cassette 10 has a first elastic member 14 provided on the cassette body 11 and capable of contacting the back surface of the pressure plate 12, and a push-up plate 13 provided on the cassette body 11. It has a second elastic member 15 that comes into contact with the back surface of the.

The first elastic member 14 is separated from the pressure plate 12 when the first end 14a is in the first position, and becomes the pressure plate 12 when the pressure plate 12 moves from the first position to the second position. It is configured to make contact. The first elastic member 14 is formed of an elastic conductor. The second end 14b of the first elastic member 14 projects outside the cassette body 11.

Specifically, as shown in FIG. 9, the first elastic member 14 is composed of, for example, torsion springs arranged on one left and right side of the cassette body 11, and is the first elastic member 14. The end 14a can come into contact with the edge portion 12b of the portion of the pressure plate 12 located behind the rotation fulcrum 12a. The first end 14a of the first elastic member 14 is urged upward by the elastic force of the first elastic member 14, and is locked to the locking portion 11k formed on the cassette body 11 to be further upward. Rotation is restricted.

As shown in FIG. 9A, when the pressure plate 12 is in the first position, the first elastic member 14 and the pressure plate 12 are not in contact with each other and are separated from each other, so that the first end of the first elastic member 14 is separated. There is a gap between the 14a and the edge 12b of the pressure plate 12.
On the other hand, as shown in FIG. 9B, when the pressure plate 12 moves from the first position to the second position, the edge portion 12b of the pressure plate 12 moves downward, and the first elastic member 14 is the first. Contact the end 14a. When the pressure plate 12 further moves toward the second position after the edge portion 12b comes into contact with the first end 14a, the first end 14a of the first elastic member 14 resists the urging force by the edge portion 12b of the pressure plate 12. Is pressed downward.

When the first end 14a of the first elastic member 14 comes into contact with the edge portion 12b of the pressure plate 12, the first elastic member 14 and the pressure plate 12 are electrically connected. For example, when the pressure plate 12 is formed by press-molding a galvanized steel plate, the plate surface of the pressure plate 12 is covered with a surface coating having low conductivity. However, the edge portion 12b of the pressure plate 12 is not covered with the surface coating because it is a cut surface at the time of press molding, and has high conductivity.
Therefore, by bringing the first end 14a of the first elastic member 14 into contact with the edge portion 12b of the pressure plate 12, the first elastic member 14 and the pressure plate 12 are surely brought into contact with each other, and the first elastic member 14 and the pressure plate 12 are brought into contact with each other. Can be stably and electrically connected.

The second end 14b of the first elastic member 14 extends to the left and right outside of the outer surface 11a on the left and right sides of the cassette body 11. Ribs 11c protruding to the left and right outside are formed on the left and right outer surfaces 11a and 11b of the cassette body 11, respectively. A through hole 11d penetrating in the vertical direction is formed in the rib 11c formed on the outer surface 11a on one side on the left and right sides. The second end 14b of the first elastic member 14 is urged downward by the elastic force of the first elastic member 14, and is configured to be able to project downward from the rib 11c through the through hole 11d by the urging force.

As shown in FIG. 3, the first end 15a of the second elastic member 15 is configured to follow the vertical displacement of the push-up plate 13 and come into contact with the back surface of the push-up plate 13. The second elastic member 15 is formed of an elastic conductor.
The second elastic member 15 is composed of, for example, a torsion spring, and is arranged in a compressed state between the push-up plate 13 and the bottom surface of the cassette body 11. The second end 15b of the second elastic member 15 projects to the outside of the cassette body 11. Specifically, the second end 15b projects downward from the bottom surface 11e of the cassette body 11. A through hole 11f is formed in the bottom surface 11e of the cassette body 11 (see FIG. 8), and the second end 15b of the second elastic member 15 projects below the bottom surface 11e through the through hole 11f.

Side frames 201 extending in the front-rear direction are provided on both the left and right sides of the main body housing 2 (see FIG. 8). The left and right side frames 201 in the seat cassette accommodating portion 2a are formed with rails 201a projecting from the side frame 201 toward the left and right inward sides, respectively. The rib 11c of the cassette body 11 is configured to be slidable on the upper surface of the rail 201a, and when the seat cassette 10 is displaced between the accommodation position and the separation position, the rib 11c slides on the rail 201a. At the same time, the sheet cassette 10 is supposed to move. That is, the rail 201a is a guide member that guides the seat cassette 10 when the seat cassette 10 is displaced between the accommodation position and the separation position.

The seat cassette accommodating portion 2a of the main body housing 2 has a first electrode 26 and a second electrode 27.
The through hole 11d of the seat cassette 10 and the second end 14b of the first elastic member 14 come into contact with the first electrode 26 when the seat cassette 10 is in the accommodation position. It is provided at the position.
The through hole 11f of the seat cassette 10 and the second end 15b of the second elastic member 15 come into contact with the second electrode 27 when the seat cassette 10 is in the accommodation position. It is provided at the position.

The first electrode 26 is a conductor plate-like member provided on the rail 201a on the right side of the main body housing 2. The first electrode 26 is arranged below the through hole 11d formed in the rib 11c of the outer side surface 11a on the left and right sides of the cassette body 11.
The first electrode 26 comes into contact with the second end 14b of the first elastic member 14 projecting downward from the through hole 11d when the seat cassette 10 is in the accommodation position. The first electrode 26 is in pressure contact with the second end 14b so that the first elastic member 14 bends against the elasticity of the first elastic member 14. Further, the second end 14b of the first elastic member 14 is slidably contacting the first electrode 26 in the front-rear direction, which is the displacement direction of the seat cassette 10.
The first electrode 26 is electrically connected to the seat sensor 9.

The second electrode 27 is composed of a frame that extends in the left-right direction at the lower part of the seat cassette accommodating portion 2a and is bridged between the left and right side frames 201. The second electrode 27 is made of a conductor member and reinforces the main body housing 2.
The second electrode 27 is arranged at a position where the second end 15b of the second elastic member 15 protrudes below the seat cassette 10 and is grounded. The second electrode 27 is in pressure contact with the second end 15b of the second elastic member 15 so that the second elastic member 15 bends against the elasticity of the second elastic member 15. Further, the second end 15b of the second elastic member 15 is slidably contacting the second electrode 27 in the front-rear direction, which is the displacement direction of the seat cassette 10.

The second end 14b of the first elastic member 14 is slidably contacted with respect to the first electrode 26 in the front-rear direction, and the second end 16b of the second elastic member 15 is slidably contacted with respect to the second electrode 27 in the front-rear direction. The slidable contact ensures that the first elastic member 14 and the first electrode 26, and the second elastic member 15 and the second electrode 27 are in the accommodating position as shown in FIG. When the sheet cassette 10 is displaced from the accommodating position to the separated position as shown in FIG. 10, the first elastic member 14 and the first electrode 26, and the second elastic member 15 and the second are used. The connection with the electrode 27 can be easily released.

Further, when the sheet cassette 10 is in the accommodation position, the first end 14a of the first elastic member 14 and the edge portion 12b of the pressure plate 12 come into contact with each other, so that the first electrode 26 and the second electrode 27 are electrically connected. The first end 14a of the first elastic member 14 and the edge portion 12b of the pressure plate 12 are separated from each other, so that the first electrode 26 and the second electrode 27 are not electrically connected.

As shown in FIG. 11, the detector 92 of the seat sensor 9 is mounted on the sensor board 90. The light emitting unit 92a of the detector 92 is composed of, for example, an LED, and the cathode K of the LED is connected to the SGND.

The first transistor Tr1 and the second transistor Tr2 are mounted on the sensor substrate 90, and the collector C2 of the first transistor Tr1 and the collector C3 of the second transistor Tr2 are connected to the anode A of the LED. The first transistor Tr1 and the second transistor Tr2 are used as switching elements.
A voltage V_bias1 is applied to the emitter E2 of the first transistor Tr1, and a voltage V_bias2 is applied to the emitter E3 of the second transistor Tr2. The voltage V_bias1 and the voltage V_bias2 are set to, for example, 3.3V.

The base B2 of the first transistor Tr1 is connected to the control unit 6. The control unit 6 can output a supply command, and the supply command from the control unit 6 is input to the base B2 of the first transistor Tr1. The first transistor Tr1 is turned on when a supply command is input to the base B2. When the first transistor Tr1 is turned on, electric power is supplied to the light emitting unit 92a, and the light emitting unit 92a emits light. That is, the supply command output from the control unit 6 is a command for supplying electric power to the light emitting unit 92a of the seat sensor 9.

The base B3 of the second transistor Tr2 is connected to the SGND via the switch SW, and when the switch SW is closed and the base B3 and the SGND are connected, the second transistor Tr2 is turned on. When the second transistor Tr2 is turned on, electric power is supplied to the light emitting unit 92a, and the light emitting unit 92a emits light. Further, when the switch SW is open, the second transistor Tr2 is turned off, power is not supplied to the light emitting unit 92a, and the light emitting unit 92a does not emit light.

The light receiving portion 92b of the detector 92 is composed of, for example, a phototransistor, and the emitter E1 of the phototransistor is connected to the SGND. The collector C1 of the phototransistor is connected to the control unit 6 and is pulled up to a predetermined voltage.
When the light receiving unit 92b receives the light from the light emitting unit 92a, the collector C1 and the emitter E1 conduct with each other to output the first signal to the control unit 6, and when the light from the light emitting unit 92a is not received, the light receiving unit 92b receives the light. The second signal is output to the control unit 6 without the collector C1 and the emitter E1 conducting each other.

The switch SW is composed of a first end 14a of the first elastic member 14 and an edge portion 12b of the pressure plate 12, and when the first end 14a and the edge portion 12b come into contact with each other, the switch SW is closed and the first switch SW is closed. When the end 14a and the edge 12b are separated without contacting each other, the switch SW is opened.

The first electrode 26, which is connected to the first elastic member 14 when the sheet cassette 10 is in the accommodation position, is connected to the connection terminal 90a connected to the base B3 of the second transistor Tr2 on the sensor substrate 90. The connection circuit 90b from the connection terminal 90a of the sensor board 90 to the switch SW is composed of the first electrode 26 and the first elastic member 14 in this order from the connection terminal 90a side. Further, the connection circuit 90c from the switch SW to the SGND is composed of a pressure plate 12, a push-up plate 13, a second elastic member 15, and a second electrode 27 in this order from the switch SW side.
Further, the switch mechanism is composed as a whole by the connection circuit 90b, the switch SW, and the connection circuit 90c extending from the connection terminal 90a of the sensor board 90 to the SGND.

The sheet sensor 9 configured in this way detects the sheet 18 when the light emitting unit 92a is supplied with electric power and the actuator 93 is not located between the light emitting unit 92a and the light receiving unit 92b. If not, the light emitting unit 92a of the detector 92 emits light, and the light receiving unit 92b receives the light from the light emitting unit 92a, so that the first signal is output.

Further, the sheet sensor 9 detects the sheet 18 when the light emitting unit 92a is supplied with electric power and the actuator 93 is located between the light emitting unit 92a and the light receiving unit 92b. The light emitting unit 92a of the detector 92 emits light, but the light from the light emitting unit 92a is blocked by the actuator 93 and is not received by the light receiving unit 92b, so that a second signal is output.

Further, when the light emitting unit 92a is not supplied with electric power, the seat sensor 9 outputs a second signal because the light emitting unit 92a of the detector 92 does not emit light and the light receiving unit 92b does not receive light. ..

At this time, when the light emitting unit 92a is supplied with electric power, the pressure plate 12 and the first end 14a of the first elastic member 14 are separated, so that the first electrode 26 and the second electrode 27 are electrically connected. When the first transistor Tr1 receives a supply command from the control unit 6, and when the pressure plate 12 and the first end 14a of the first elastic member 14 come into contact with each other, the first electrode 26 and the second electrode 27 Is electrically connected.
When the first electrode 26 and the second electrode 27 are electrically connected, the light emitting unit 92a may or may not receive the supply command from the control unit 6 of the first transistor Tr1. Receive power supply.

When the light emitting unit 92a is not supplied with electric power, the pressure plate 12 and the first end 14a of the first elastic member 14 are separated so that the first electrode 26 and the second electrode 27 are electrically connected. This is the case where the first transistor Tr1 does not receive the supply command from the control unit 6.

In the image forming apparatus 1, a power supply circuit SC for supplying power to the light emitting unit 92a of the seat sensor 9 is configured by a circuit including the first transistor Tr1, the second transistor Tr2, and the switch SW.
Further, in the image forming apparatus 1, the seat cassette 10, the main body housing 2, the seat cassette accommodating portion 2a, the first electrode 26, the second electrode 27, the seat conveying portion 20, the driving unit 4, the seat sensor 9, and the rotation pulse signal. The sheet transfer device is composed of the output unit 95, the control unit 6, and the power supply circuit SC.

In the present embodiment, the pressure plate 12 and the push-up plate 13 are formed of a galvanized steel plate, but they do not necessarily have to be formed of a galvanized steel plate, but are formed of a conductor such as another metal or a conductive resin. May be good. Further, the pressure plate 12 and the push-up plate 13 do not necessarily have to be entirely formed of conductors, and when the pressure plate 12 and the first end 14a of the first elastic member 14 come into contact with each other, the first electrode 26 and the second electrode As long as the structure is such that the 27 is conductive, a structure in which a conductor and a non-conductor may be combined may be used. For example, the pressure plate 12 and the push-up plate 13 may have a structure in which a resin plate and a metal plate are bonded together.

[First embodiment of control for calculating the number of sheets S]
In the image forming apparatus 1, the number of sheets 18 accommodated in the sheet cassette 10 (hereinafter, referred to as "the number of sheets S") can be calculated by the control unit 6, and the number of sheets S can be calculated. In addition, the following control is performed.
In the control for calculating the number of sheets S, a mechanism for reducing the calculation error when calculating the number of sheets S and moving the push-up plate 13 and the pressure plate 12 when calculating the number of sheets S (hereinafter, "press plate"). It is possible to detect whether or not a failure has occurred in the moving mechanism).

(Update process S100 of the number of sheets S when the sheet cassette 10 is inserted)
First, the update process S100 of the number of sheets S when the sheet cassette 10 displaced at the separation position is inserted to the accommodation position of the sheet cassette accommodating portion 2a will be described.

As shown in FIG. 12, when the sheet cassette 10 in the separated position is inserted to the accommodating position (S101), the first elastic member 14 on the sheet cassette 10 side and the first electrode 26 on the sheet cassette accommodating portion 2a come into contact with each other. The second elastic member 15 on the seat cassette 10 side and the second electrode 27 on the seat cassette accommodating portion 2a come into contact with each other to conduct conduction (S103).
Further, when the sheet cassette 10 is inserted to the accommodation position, the pressure plate 12 is displaced to the first position, and the edge portion 12b of the pressure plate 12 and the first end 14a of the first elastic member 14 are separated. , The first electrode 26 and the second electrode 27 are not electrically connected, and the seat sensor 9 outputs a second signal (S105).

Here, when the seat cassette 10 in the separated position is inserted to the accommodation position, the seat cassette 10 is inserted and removed from the sheet cassette accommodating portion 2a, and the seat 18 is supported by the pressure plate 12. In the first state where the pressure plate moving mechanism has not failed, the seat cassette 10 is inserted and removed from the seat cassette accommodating portion 2a, the seat 18 is not supported by the pressure plate 12, and the pressure plate moving mechanism is not supported. In the second state in which no failure has occurred, the seat cassette 10 is inserted and removed from the seat cassette accommodating portion 2a, and the seat 18 is supported by the pressure plate 12 or the seat 18 is not supported by the pressure plate 12. In addition, there is a third state in which the pressure plate moving mechanism has a failure.

This "failure in the pressure plate moving mechanism" means that the sensor substrate 90 is connected because the pressure plate 12 does not move normally when the motor 40 is driven to move the pressure plate 12 upward. This refers to a state in which at least a part of the switch mechanism from the terminal 90a to the connection circuit 90b, the switch SW, and the connection circuit 90c to the SGND has a portion that is not electrically connected.

Specifically, for example, the pressure plate moving gear 411 of the transmission mechanism 41 is damaged or missing, and the pressure plate drive gear 42 connected to the motor 40 and the pressure plate moving gear 411 are not normally engaged with each other, and the motor 40 The driving force of the pressure plate 12 is not transmitted to the transmission mechanism 41 and the pressure plate 12 does not move upward.
Further, for example, when the first elastic member 14 is deformed or missing and the pressure plate 12 moves from the first position to the second position, it does not come into contact with the pressure plate 12, and the first elastic member 14 and the pressure plate 12 do not come into contact with each other. Since the switch SW is not electrically connected to and from, the switch SW may not be closed.

In FIGS. 14, 15, and 16, when the sheet cassette 10 is in the first state, the second state, and the third state, the voltage V_bias1 is applied to the first transistor Tr1 when calculating the number of sheets S, respectively. A timing chart showing the state, the open / closed state of the switch SW, the applied state of the voltage V_bias2 to the second transistor Tr2, the output state of the supply command from the control unit 6, and the output states of the first signal and the second signal from the seat sensor 9. It is described.

As shown in FIGS. 14, 15, and 16, when the seat cassette 10 is inserted to the accommodation position, the seat sensor is in all the cases where the seat cassette 10 is in the first state, the second state, and the third state. 9 outputs the second signal (S105).
In this state, the control unit 6 transmits a supply command to the first transistor Tr1 (S107). When the supply command is transmitted from the control unit 6, electric power is supplied to the light emitting unit 92a of the seat sensor 9, and the light emitting unit 92a emits light. That is, when the pressure plate 12 is displaced to the first position and the switch SW is in the open state, the light emitting unit 92a is forcibly turned on by outputting a supply command from the control unit 6.

When the light emitting unit 92a emits light, the pressure plate 12 is displaced to the first position and the actuator 93 does not detect the seat 18, so that the light from the light emitting unit 92a is received by the light receiving unit 92b and the seat sensor 9 gives the second light. One signal is output (S109). In this case, the seat sensor 9 outputs the first signal in all the cases where the seat cassette 10 is in the first state, the second state, and the third state.

After that, the control unit 6 stops the transmission of the supply command (S111). When the supply command is stopped, no light is emitted from the light emitting unit 92a. That is, when the control unit 6 stops the supply command, the forced lighting of the light emitting unit 92a is released. When the light emitting unit 92a stops emitting light, the light receiving unit 92b does not receive light, so that the sheet sensor 9 outputs a second signal (S113). In this case, the seat sensor 9 outputs the second signal in all the cases where the seat cassette 10 is in the first state, the second state, and the third state.

The control unit 6 starts the motor 40 after stopping the supply command and outputting the second signal from the seat sensor 9 (S115). When the motor 40 is started, the push-up plate 13 is rotated upward by the driving force from the motor 40, and the upward movement of the pressure plate 12 is started (S117).
After starting the motor 40, the control unit 6 determines whether or not the seat sensor 9 outputs the first output signal (S119).

When the control unit 6 determines in step S119 that the sheet sensor 9 is outputting the first output signal, the control unit 6 resets the number of sheets S currently held in the control unit 6 to 0 (S121) and controls. The value of the counter C provided in the unit 6 for measuring the rotation speed of the motor 40 is reset to 0 (S123).

The control unit 6 determines in step S119 that the seat sensor 9 is outputting the first output signal, resets the values of the number of seats S and the counter C (S121, S123), and then increments the counter C. Start and start measuring the rotation speed of the motor 40 (S125). That is, as shown in FIG. 19, the control unit 6 determines the rotation speed of the motor 40 received from the rotation pulse signal output unit 95 from the time when the signal received from the seat sensor 9 is switched from the second signal to the first signal. Start measuring the number of rotation pulse signals shown.

In this case, when the motor 40 is started with the pressure plate 12 in the first position (S115), the push-up plate 13 is driven by the motor 40 and the pressure plate 12 starts to move upward, but the pressure plate 12 is on the upper side. When the movement to the first elastic member 14 is started, the first end 14a of the first elastic member 14 and the edge portion 12b of the pressure plate 12 come into contact with each other, and the first electrode 26 and the second electrode 27 are electrically connected. .. When the first electrode 26 and the second electrode 27 are electrically connected, the light emitting portion 92a of the seat sensor 9 emits light.

Further, when the motor 40 is started, the pressure plate 12 is in the first position and the actuator 93 is displaced to a position not intervening between the light emitting unit 92a and the light receiving unit 92b, so that the light from the light emitting unit 92a is received. The light is received by the unit 92b.
As a result, the output signal from the seat sensor 9 is switched from the second signal to the first signal, and when the signal received from the seat sensor 9 is switched from the second signal to the first signal, the control unit 6 motors from the time of switching. Start counting 40 revolutions.

When it is determined in step S119 that the seat sensor 9 is outputting the first output signal, it means that the seat cassette 10 is in the first state and the second state.
Further, the counter C is provided in the control unit 6, and for example, the rotation number of the motor 40 is counted by incrementing the count value by +1 each time the rotation pulse signal output from the rotation pulse signal output unit 95 is received. It is configured in.

On the other hand, when the control unit 6 determines in step S119 that the seat sensor 9 does not output the first output signal, whether or not a predetermined time has elapsed from the time when the transmission of the supply command to the first transistor Tr1 is stopped. Is determined (S127).
If the control unit 6 determines in step S127 that the predetermined time has not elapsed, the control unit 6 executes step S119 again.

Further, when the control unit 6 determines in step S127 that the predetermined time has elapsed, it determines that the pressure plate moving mechanism has a failure, such as the pressure plate 12 not moving upward (S129). ).
That is, if the seat sensor 9 does not output the first output signal even after a predetermined time has elapsed from the time when the transmission of the supply command to the first transistor Tr1 is stopped, the pressure plate 12 will be pressed even if the motor 40 is started. Since the light emitting unit 92a of the seat sensor 9 does not emit light due to reasons such as the switch SW not switching to the closed state without normally moving upward, the control unit 6 has a failure in the pressure plate moving mechanism. Judge.
In this way, when the control unit 6 determines that the pressure plate moving mechanism has a failure, it is a case where the seat cassette 10 is in the third state.

When the control unit 6 determines that the pressure plate moving mechanism has a failure, the control unit 6 notifies the outside of the information that the pressure plate moving mechanism has a failure (S131). Information indicating that a failure has occurred may be notified, for example, by displaying the information on a display unit included in the image forming apparatus 1 or by emitting a sound from a speaker included in the image forming apparatus 1. Can be done.
After notifying the information that the pressure plate moving mechanism has a failure, the control unit 6 stops the motor 40 (S133) and ends the update process S100 of the number of sheets S.

As shown in FIG. 13, the control unit 6 determines whether or not the seat sensor 9 is outputting the second signal after starting the measurement of the rotation speed of the motor 40 (S135). That is, as shown in FIG. 19, the control unit 6 determines whether or not the signal received from the seat sensor 9 has been switched from the first signal to the second signal.

When the control unit 6 determines in step S135 that the seat sensor 9 is outputting the second signal, the control unit 6 stops the increment of the counter C (S137), and counts from the start to the stop of the increment of the counter C. Find the value.
The control unit 6 calculates the updated number of sheets S by executing the calculation process S300 of the number of sheets S using the obtained count value of the counter C.

In the sheet sensor 9 in which the light receiving unit 92b receives the light from the light emitting unit 92a and outputs the first signal, the contactor 91 comes into contact with the upper surface of the sheet 18 supported on the pressure plate 12. The light from the light emitting unit 92a is blocked by the actuator 93 and is not received by the light receiving unit 92b, so that the state switches to the state of outputting the second signal.
That is, when the control unit 6 determines in step S135 that the seat sensor 9 is outputting the second signal, it is a case where the seat cassette 10 is in the first state.

On the other hand, when the control unit 6 determines in step S135 that the seat sensor 9 does not output the second signal, whether or not the count value of the counter C is larger than the preset maximum value Cmax. The determination is made (S139).
When the control unit 6 determines in step S139 that the count value of the counter C is larger than Cmax, the control unit 6 stops the increment of the counter C (S141).

The state in which the count value of the counter C becomes larger than Cmax is a state in which the pressure plate 12 that does not support the seat 18 has moved upward to a position where it comes into contact with the pickup roller 21.
That is, when the control unit 6 determines in step S139 that the count value of the counter C is larger than Cmax, it is a case where the seat cassette 10 is in the second state.
When the control unit 6 determines in step S139 that the count value of the counter C is larger than Cmax, the number of sheets S is not updated, and the state of being reset to 0 in step S121 is maintained.

If the control unit 6 determines in step S139 that the count value of the counter C is not larger than Cmax, the control unit 6 returns to step S135 and re-executes the determination of whether or not the seat sensor 9 is outputting the second signal. do.

The control unit 6 determines whether or not the number of sheets S held in the control unit 6 is 0 after the calculation process S300 for the number of sheets S is completed or after the increment of the counter C is stopped in step S141. The determination is made (S143).

When the control unit 6 determines in step S143 that the number of sheets S held by the control unit 6 is not 0, the control unit 6 determines that the printing preparation is completed (S145), stops the motor 40 (S147), and then stops the motor 40 (S147). The update process of the number of sheets S is completed.
Further, when the control unit 6 determines in step S143 that the number of sheets S held by the control unit 6 is 0, the control unit 6 displays on the display unit of the image forming apparatus 1 that there is no sheet. After that (S149), the motor 40 is stopped (S147), and the update process S100 of the number of sheets S is completed.

As described above, in the update process S100 of the number of sheets S, the control unit 6 gives a supply command to the power supply circuit SC before the push-up plate 13 is displaced by controlling the drive unit 4 to move the pressure plate 12 upward. When the control unit 6 receives the first signal from the seat sensor 9 in response to the transmission, the control unit 6 stops the transmission of the supply command and presses the drive unit 4 on the upper side of the plate 13. If the first signal is not received from the seat sensor 9 even after a predetermined time has elapsed from the time when the transmission of the supply command to the power supply circuit SC is stopped when the control is performed so as to move the power supply circuit to the power supply circuit SC, the control unit 6 performs. It is configured to determine that a failure has occurred in the pressure plate moving mechanism and notify it.
This makes it possible to detect whether or not a failure has occurred in the pressure plate moving mechanism before calculating the number of sheets S based on the amount of movement of the pressure plate 12 upward.

When an image forming instruction is input to the image forming apparatus 1 at the time when the updating process of the number of sheets S is completed or after the updating process of the number of sheets S is completed, the control unit 6 causes the image forming unit 5 and the like to move. It is driven to form an image on the sheet 18.
In this case, each time the control unit 6 takes out one sheet 18 from the sheet cassette 10, the control unit 6 determines the number of sheets S to be a value obtained by subtracting 1 from the current number of sheets (S = S-1).

As described above, in the image forming apparatus 1, the pressure plate 12 is configured to be displaced to the first position when the sheet cassette 10 is in the separated position. Therefore, in the updating process S100 of the number of sheets S, for example, when the sheet cassette 10 is pulled out from the accommodating position to the separated position and returned to the accommodating position again, the pressure plate 12 and the first elastic member 14 are surely the first. After detecting that the first electrode 26 and the second electrode 27 are electrically connected by contact with the one end 14a, the amount of movement of the pressure plate 12 upward is calculated based on the rotation speed of the motor 40. It is possible.

Further, since the first electrode 26 is a plate-shaped member arranged on the rail 201a of the main body housing 2 and the second electrode 27 is a frame arranged under the seat cassette accommodating portion 2a, the apparatus configuration is complicated. The first electrode 26 and the second electrode 27 can be arranged without using the above, and the miniaturization of the sheet transfer device is not hindered.

(Calculation processing S300 for the number of sheets S)
Next, the calculation process S300 for the number of sheets S will be described.
As shown in FIG. 17, in the calculation process S300 of the number of seats S, the control unit 6 first receives from the seat sensor 9 from the time when the signal received from the seat sensor 9 is switched from the second signal to the first signal. The seat loading height H until the signal is switched from the first signal to the second signal is calculated (S301).
Specifically, the seat loading height is obtained by multiplying the value of the counter C counted between the start of the increment (S125) and the stop of the increment (S137) by the constant A and adding the constant B. Calculate H.

In this case, the constant A is a negative value, and is a proportional constant between the value of the counter C and the seat loading height H.
The constant B is a positive value, and the sheet loading height when the sheet is loaded to the position where the sheet sensor 9 detects the sheet 18 on the upper surface of the pressure plate 12 in the state where the pressure plate 12 is in the lowest position (first position). Is a value equal to.

The value of the counter C is a value corresponding to the amount of movement of the pressure plate 12 upward from the start of the increment (S125) to the stop of the increment (S137). Further, the sheet loading height H corresponds to the amount of movement of the pressure plate 12 to the upper side, and the value of the sheet loading height H decreases as the amount of movement of the pressure plate 12 to the upper side increases.

Summarizing the above, the seat loading height H is expressed by the following mathematical formula.
(Sheet loading height H) = {(constant A) x (counter C value)} + (constant B) ... (Equation 1)
The relationship between (seat loading height H) and (counter C value) is drawn in a graph as shown in FIG.

Next, the control unit 6 calculates the number S of the seats 18 corresponding to the seat loading height H by dividing the seat loading height H by the thickness (seat thickness) t of the seat 18 (S302).
In this case, the value of the sheet thickness t corresponding to the thickness of the sheet 18 housed in the cassette body 11 is preset in the control unit 6.

As described above, in the sheet transfer device included in the image forming apparatus 1, the control unit 6 calculates the sheet loading height H on the pressure plate 12 based on the number of rotation pulse signals output from the rotation pulse signal output unit 95. At that time, the number of rotation pulse signals received from the rotation pulse signal output unit 95 starts to be counted from the time when the signal received from the seat sensor 9 is switched from the second signal to the first signal, so that the counter C measures the signal. The rotation speed of the motor 40 does not include the rotation speed from the start of driving the push-up plate 13 to the actual start of operation of the push-up plate 13.

As a result, the variation in the rotation speed of the motor 40 that occurs from the start of driving the motor 40 to the actual start of operation of the push-up plate 13 can be removed from the measured value of the counter C, and is based on the seat loading height H. When the number of sheets S on the pressure plate 12 is obtained, it is possible to suppress an error in the required number of sheets S.

Further, when the seat loading height H is calculated based on the number of rotation pulse signals to obtain the number of sheets S on the pressure plate 12, the signal received from the seat sensor 9 is used to start moving the pressure plate 12 upward. Since it is detected, it is not necessary to use a dedicated sensor, and it is possible to simplify the device configuration and suppress the cost increase.
Since the sheet loading height H on the pressure plate 12 can be accurately obtained, the number of sheets S on the pressure plate calculated based on the sheet loading height H and the sheet thickness t can also be accurately obtained.

(Update process S200 for the number of sheets S when the power is turned on)
Next, the update process S200 of the number of sheets S when the power of the image forming apparatus 1 in the power off state is turned on will be described.

In the image forming apparatus 1 at the time when the power is turned on, the sheet cassette 10 is not inserted or removed from the seat cassette accommodating portion 2a between the time when the power is turned off last time and the time when the power is turned on this time (when the power is turned off). That is, the seat cassette 10 is still inserted in the accommodation position of the seat cassette accommodating portion 2a, and the seat cassette 10 is inserted and removed from the seat cassette accommodating portion 2a when the power is turned off, that is, accommodating. There is a state in which the sheet cassette 10 at the position is taken out to the separation position and then reinserted into the accommodation position.

If the sheet cassette 10 is not inserted or removed when the power is turned off, the sheet 18 is supported by the pressure plate 12, and the sheet 18 supported by the pressure plate 12 is moved upward to a position where paper can be fed, and the pressure plate 12 and the first 1 If the first end 14a of the elastic member 14 is in contact with the sheet 18 and the sheet 18 is detected by the sheet sensor 9, the sheet sensor 9 sends a second signal when the image forming apparatus 1 is turned on. Output.

In this case, in the seat cassette 10, the seat cassette 10 has not been inserted or removed from the seat cassette accommodating portion 2a, the seat 18 is supported by the pressure plate 12, and the pressure plate moving mechanism has not failed. It is in a state. FIG. 22 shows a state in which the voltage V_bias1 is applied to the first transistor Tr1, an open / closed state of the switch SW, and a voltage V_bias2 with respect to the second transistor Tr2 when calculating the number of sheets S when the sheet cassette 10 is in the fourth state. A timing chart showing the application state of the above, the output state of the supply command from the control unit 6, and the output state of the first signal and the second signal from the seat sensor 9 is described.

If the sheet cassette 10 is not inserted or removed when the power is turned off, the sheet 18 is not supported by the pressure plate 12, the pressure plate 12 moves to the uppermost position, and the pressure plate 12 and the first elastic member 14 are first. If the end 14a is in contact with the sheet and the sheet 18 is not detected by the sheet sensor 9, the sheet sensor 9 outputs a first signal when the image forming apparatus 1 is turned on.

In this case, in the seat cassette 10, the seat cassette 10 has not been inserted or removed from the seat cassette accommodating portion 2a, the seat 18 is not supported by the pressure plate 12, and the pressure plate moving mechanism has not failed. It is in a state. FIG. 23 shows a state in which the voltage V_bias1 is applied to the first transistor Tr1, an open / closed state of the switch SW, and a voltage V_bias2 with respect to the second transistor Tr2 when calculating the number of sheets S when the sheet cassette 10 is in the fifth state. A timing chart showing the application state of the above, the output state of the supply command from the control unit 6, and the output state of the first signal and the second signal from the seat sensor 9 is described.

Further, when the seat cassette 10 is inserted or removed when the power is turned off, the pressure plate 12 is displaced to the first position, and the pressure plate 12 and the first end 14a of the first elastic member 14 are separated from each other. When the image forming apparatus 1 is turned on, the seat sensor 9 outputs a second signal. In this case, the sheet cassette 10 is in the above-mentioned first state, second state, or third state.

As shown in FIG. 20, when the image forming apparatus 1 is turned on (S201), the control unit 6 determines whether or not the seat sensor 9 is outputting the second signal (S203).
When the control unit 6 determines in step S203 that the seat sensor 9 does not output the second signal, that is, outputs the first signal, the control unit 6 determines that the seat cassette 10 is in the fifth state, and the figure shows the figure. As shown in FIG. 21, after displaying "no sheet" on the display unit of the image forming apparatus 1 (S257), the update process S200 of the number of sheets S is terminated.

On the other hand, when the control unit 6 determines in step S203 that the seat sensor 9 is outputting the second signal, the control unit 6 transmits a supply command to the first transistor Tr1 (S205).
After transmitting the supply command, the control unit 6 determines whether or not the seat sensor 9 is outputting the first signal (S207).
When the control unit 6 transmits a supply command, the light emitting unit 92a of the sheet sensor 9 is forcibly emitted, and when the light from the light emitting unit 92a is received by the light receiving unit 92b, the sheet sensor 9 outputs a first signal and the light emitting unit If the light from the 92a is not received by the light receiving unit 92b, the sheet sensor 9 outputs a second signal.

When the control unit 6 determines in step S207 that the seat sensor 9 does not output the first signal, the seat 18 is supported by the pressure plate 12, and the seat cassette 10 is not inserted or removed when the power is turned off. Judgment (S209).
When the control unit 6 transmits a supply command, the seat sensor 9 outputs the second signal without outputting the first signal because the light emitting unit 92a of the seat sensor 9 emits light. This is because the light from the unit 92a is blocked by the actuator 93 and is not received by the light receiving unit 92b. That is, the seat cassette 10 is in the fourth state, and the control unit 6 determines that the seat 18 is supported by the pressure plate 12 and that the seat cassette 10 is not inserted or removed when the power is turned off.

In this case, the number of sheets S held in the control unit 6 before the power is turned off is continuously used without updating the number of sheets S (S211).
After that, the control unit 6 determines that the print preparation is completed (S213), stops the motor 40 (S215), and ends the update process S200 for the number of sheets S.

On the other hand, when the control unit 6 determines in step S207 that the seat sensor 9 is outputting the first signal, the control unit 6 stops the transmission of the supply command (S217).
When the control unit 6 determines in step S207 that the seat sensor 9 is outputting the first signal, it is a case where the seat cassette 10 is in the first state, the second state, or the third state.

Further, when the control unit 6 stops transmitting the supply command in step S217, the forced lighting of the light emitting unit 92a is released, and the light receiving unit 92b does not receive the light from the light emitting unit 92a, so that the seat sensor 9 receives the second signal. Output (S219). In this case, the seat sensor 9 outputs the second signal in all the cases where the seat cassette 10 is in the first state, the second state, and the third state.

The control unit 6 starts the motor 40 after stopping the supply command and outputting the second signal from the seat sensor 9 (S221). When the motor 40 is started, the push-up plate 13 is rotated upward by the driving force from the motor 40, and the upward movement of the pressure plate 12 is started (S223).
After starting the motor 40, the control unit 6 determines whether or not the seat sensor 9 outputs the first output signal (S225).

When the control unit 6 determines in step S225 that the sheet sensor 9 is outputting the first output signal, the control unit 6 resets the number of sheets S currently held in the control unit 6 to 0 (S227) and controls. The value of the counter C provided in the unit 6 for measuring the rotation speed of the motor 40 is reset to 0 (S229).

The control unit 6 determines in step S225 that the seat sensor 9 is outputting the first output signal, resets the values of the number of seats S and the counter C (S227, S229), and then increments the counter C. Start and start measuring the rotation speed of the motor 40 (S231). That is, as shown in FIG. 19, the control unit 6 determines the rotation speed of the motor 40 received from the rotation pulse signal output unit 95 from the time when the signal received from the seat sensor 9 is switched from the second signal to the first signal. Start measuring the number of rotation pulse signals shown.
When it is determined in step S225 that the seat sensor 9 is outputting the first output signal, it means that the seat cassette 10 is in the first state and the second state.

On the other hand, when the control unit 6 determines in step S225 that the seat sensor 9 does not output the first output signal, whether or not a predetermined time has elapsed from the time when the transmission of the supply command to the first transistor Tr1 is stopped. Is determined (S233).
If the control unit 6 determines in step S233 that the predetermined time has not elapsed, the control unit 6 executes step S225 again.

Further, when the control unit 6 determines in step S233 that the predetermined time has elapsed, it determines that the pressure plate moving mechanism has a failure, such as the pressure plate 12 not moving upward (S235). ).
In this way, when the control unit 6 determines that the pressure plate moving mechanism has a failure, it is a case where the seat cassette 10 is in the third state.

When the control unit 6 determines that the pressure plate moving mechanism has a failure, the control unit 6 notifies the outside of the information that the pressure plate moving mechanism has a failure (S237). Information indicating that a failure has occurred may be notified, for example, by displaying the information on a display unit included in the image forming apparatus 1 or by emitting a sound from a speaker included in the image forming apparatus 1. Can be done.
After notifying the information that the pressure plate moving mechanism has a failure, the control unit 6 stops the motor 40 (S239) and ends the update process S200 for the number of sheets S.

As shown in FIG. 21, the control unit 6 determines whether or not the seat sensor 9 is outputting the second signal after starting the measurement of the rotation speed of the motor 40 (S241). That is, as shown in FIG. 19, the control unit 6 determines whether or not the signal received from the seat sensor 9 has been switched from the first signal to the second signal.

When the control unit 6 determines in step S241 that the seat sensor 9 is outputting the second signal, the control unit 6 stops the increment of the counter C (S243), and counts from the start to the stop of the increment of the counter C. Find the value.
The control unit 6 calculates the updated number of sheets S by executing the calculation process S300 of the number of sheets S using the obtained count value of the counter C.
When the control unit 6 determines in step S241 that the seat sensor 9 is outputting the second signal, the seat cassette 10 is in the first state.

On the other hand, when the control unit 6 determines in step S241 that the seat sensor 9 does not output the second signal, whether or not the count value of the counter C is larger than the preset maximum value Cmax. The determination is made (S245).
When the control unit 6 determines in step S245 that the count value of the counter C is larger than Cmax, the control unit 6 stops the increment of the counter C (S247).

When the control unit 6 determines in step S245 that the count value of the counter C is larger than Cmax, it is a case where the seat cassette 10 is in the second state.
When the control unit 6 determines in step S245 that the count value of the counter C is larger than Cmax, the number of sheets S is not updated, and the state of being reset to 0 in step S227 is maintained.

When the control unit 6 determines in step S245 that the count value of the counter C is not larger than Cmax, the control unit 6 returns to step S241 and re-executes the determination of whether or not the seat sensor 9 is outputting the second signal. do.

The control unit 6 determines whether or not the number of sheets S held in the control unit 6 is 0 after the calculation process S300 for the number of sheets S is completed or after the increment of the counter C is stopped in step S247. The determination is made (S249).

When the control unit 6 determines in step S249 that the number of sheets S held by the control unit 6 is not 0, the control unit 6 determines that printing preparation is complete (S251), stops the motor 40 (S253), and then stops the motor 40 (S253). The update process of the number of sheets S is completed.
Further, when the control unit 6 determines in step S249 that the number of sheets S held by the control unit 6 is 0, the control unit 6 displays on the display unit of the image forming apparatus 1 that there is no sheet. After that (S255), the motor 40 is stopped (S253), and the update process S200 for the number of sheets S is completed.

When an image formation instruction is input to the image forming apparatus 1 at the time when the updating process of the number of sheets S is completed or after the updating process of the number of sheets S is completed, the control unit 6 drives the image forming unit 5 and the like. Image formation is performed on the sheet 18.
In this case, each time the control unit 6 takes out one sheet 18 from the sheet cassette 10, the control unit 6 determines the number of sheets S to be a value obtained by subtracting 1 from the current number of sheets (S = S-1).

In this way, even in the update process S200 of the number of sheets S when the power of the image forming apparatus 1 is turned on, the pressure plate moving mechanism is used before calculating the number of sheets S based on the amount of movement of the pressure plate 12 upward. It is possible to detect whether or not a failure has occurred.
Further, when the sheet loading height H corresponding to the amount of movement of the pressure plate 12 upward is calculated based on the number of rotation pulse signals to obtain the number of sheets S on the pressure plate 12, the signal received from the sheet sensor 9 is used. Since the start of movement of the pressure plate 12 to the upper side is detected by using the pressure plate 12, it is not necessary to use a dedicated sensor, and it is possible to simplify the device configuration and suppress the cost increase.

[Second embodiment of the configuration for calculating the number of sheets S]
Next, a second embodiment of the configuration for calculating the number of sheets S will be described.
In the second embodiment of the configuration for calculating the number of sheets S, the connection destination of the base B2 of the first transistor Tr1 on the sensor substrate 90 is not the control unit 6, but the clock pulse signal output unit included in the image forming apparatus 1. It differs from the first embodiment in that it is 96. In the description of the second embodiment, the parts different from the first embodiment will be mainly described, and the parts common to the first embodiment will be omitted as appropriate.

As shown in FIG. 24, the image forming apparatus 1 includes a clock pulse signal output unit 96, and the clock pulse signal output unit 96 is connected to the base B2 of the first transistor Tr1. The clock pulse signal output unit 96 is a signal output unit that outputs a clock pulse signal at regular intervals.
As shown in FIG. 25, the clock pulse signal output from the clock pulse signal output unit 96 is a pulse signal in which an off signal having a predetermined potential and an on signal having a higher potential than the off signal repeatedly appear in a fixed cycle. Yes, it is input to the base B2 of the first transistor Tr1.

The first transistor Tr1 is turned on when an ON signal of a clock pulse signal is input to the base B2. When the first transistor Tr1 is turned on, electric power is supplied to the light emitting unit 92a, and the light emitting unit 92a emits light.
The first transistor Tr1 is turned off when an off signal of the clock pulse signal is input to the base B2. When the first transistor Tr1 is turned off, power is not supplied to the light emitting unit 92a, and the light emitting unit 92a does not emit light.

Therefore, when the clock pulse signal in which the on signal and the off signal are repeatedly output at a constant cycle is input to the first transistor Tr1, power is supplied to the light emitting unit 92a in synchronization with the clock pulse signal, and the light emitting unit 92a is supplied with power. The 92a emits light intermittently in synchronization with the clock pulse signal.

As described above, the power supply circuit SC in the present embodiment can receive the clock pulse signal output from the clock pulse signal output unit 96, and the pressure plate 12 and the first end 14a of the first elastic member 14 are separated from each other. As a result, when the first electrode 26 and the second electrode 27 are not electrically connected and a clock pulse signal is received, power is supplied to the light emitting unit 92a in synchronization with the clock pulse signal to emit light. When the part 92a is made to emit light intermittently and the clock pulse signal is not received, no power is supplied to the light emitting part 92a, and the pressure plate 12 and the first end 14a of the first elastic member 14 come into contact with each other. When the electrode 26 and the second electrode 27 are electrically connected, power is supplied to the light emitting unit 92a.

In the present embodiment, the seat cassette 10, the main body housing 2, the seat cassette accommodating portion 2a, the first electrode 26, the second electrode 27, the seat transport portion 20, the drive unit 4, the seat sensor 9, and the rotation pulse signal output unit 95. , The clock pulse signal output unit 96, the control unit 6, and the power supply circuit SC constitute a sheet transfer device.

[Second embodiment of control for calculating the number of sheets S]
The image forming apparatus 1 connects the clock pulse signal output unit 96 to the base B2 of the first transistor Tr1 as in the second embodiment of the configuration for calculating the number of sheets S, and receives the clock pulse signal output unit 96 from the clock pulse signal output unit 96. Even when the clock pulse signal is configured to be input to the base B2 of the first transistor Tr1, the above-mentioned update process S100 for the number of sheets S, update process S200 for the number of sheets S, and calculation process S300 for the number of sheets S are performed. It can be executed in the same manner as in the case of the first embodiment of the control for calculating the number of sheets S.

The update process S100 of the number of sheets S in this embodiment is performed as follows.
As shown in FIG. 26, when the sheet cassette 10 in the separated position is inserted to the accommodating position (S101), the first elastic member 14 on the sheet cassette 10 side and the first electrode 26 on the sheet cassette accommodating portion 2a come into contact with each other. The second elastic member 15 on the seat cassette 10 side and the second electrode 27 on the seat cassette accommodating portion 2a come into contact with each other to conduct conduction (S103).

Further, in the state where the seat cassette 10 is inserted to the accommodation position, the power supply circuit SC receives the clock pulse signal from the clock pulse signal output unit 96 (S106), and as shown in FIG. 25, the seat sensor 9 is the third. One signal is output intermittently (S108).
Here, "the seat sensor 9 intermittently outputs the first signal" means that the seat sensor 9 synchronizes the on signal and the off signal of the clock pulse signal, and the first signal and the second signal are constant. It means to output repeatedly in the cycle of.

FIG. 25 shows a state in which the voltage V_bias1 is applied to the first transistor Tr1, an open / closed state of the switch SW, and a voltage V_bias2 with respect to the second transistor Tr2 when calculating the number of sheets S when the sheet cassette 10 is in the first state. A timing chart showing the application state of the above, the output state of the clock pulse signal from the signal output unit 96 for clocking, and the output state of the first signal and the second signal from the seat sensor 9 is described.
When the sheet cassette 10 in the separated position is inserted to the accommodation position, the sheet cassette 10 has a first state, a second state, and a third state, and in step S108, the first state and the first state are present. The seat sensor 9 intermittently outputs the first signal in all the states of the second state and the third state.

The control unit 6 starts the motor 40 after the seat sensor 9 intermittently outputs the first signal (S115). When the motor 40 is started, the push-up plate 13 is rotated upward by the driving force from the motor 40, and the upward movement of the pressure plate 12 is started (S117).
After starting the motor 40, the control unit 6 determines whether or not the seat sensor 9 continuously outputs the first output signal (S120). Here, "the sheet sensor 9 continuously outputs the first output signal" means a time sufficiently longer than the length of the on signal of the clock pulse signal, for example, a length of a plurality of times or more the length of the on signal of the clock pulse signal. It means that the first signal is continuously output for that time.

When the control unit 6 determines in step S120 that the sheet sensor 9 continuously outputs the first output signal, the control unit 6 is currently performing the same as in the case of the first embodiment of the control for calculating the number of sheets S. The number of sheets S held in the control unit 6 is reset to 0 (S121), and the value of the counter C provided in the control unit 6 for measuring the rotation speed of the motor 40 is reset to 0 (S123). The control unit 6 further starts incrementing the counter C and starts measuring the rotation speed of the motor 40 (S125).

After the control unit 6 starts measuring the rotation speed of the motor 40, steps S135 to S149 are performed as in the case of the first embodiment of the control for calculating the number of sheets S (see FIG. 13).
However, the determination of whether or not the seat sensor 9 outputs the second signal, which is performed in step S135, is more specifically whether or not the seat sensor 9 continuously outputs the second signal, that is, whether or not the seat sensor 9 outputs the second signal. , It is determined whether or not the seat sensor 9 has switched from the state of continuously outputting the first signal to the state of continuously outputting the second signal.

On the other hand, when the control unit 6 determines in step S120 that the seat sensor 9 does not continuously output the first output signal, the control unit 6 starts the motor 40 and starts moving the pressing plate 13 upward. It is determined whether or not the predetermined time has elapsed (S128).
If the control unit 6 determines in step S128 that the predetermined time has not elapsed, the control unit 6 executes step S120 again.

Further, when the control unit 6 determines in step S128 that the predetermined time has elapsed, it determines that the pressure plate moving mechanism has a failure, such as the pressure plate 12 not moving upward (S129). ).
That is, if the seat sensor 9 does not continuously output the first output signal even after a predetermined time has elapsed from the time when the motor 40 is started and the pressing plate 13 starts moving upward, the motor 40 is turned on. Since the light emitting unit 92a of the seat sensor 9 does not continuously emit light due to reasons such as the pressure plate 12 not normally moving upward even when started and the switch SW not switching to the closed state, the control unit 6 Determines that the pressure plate moving mechanism has failed.
In this way, when the control unit 6 determines that the pressure plate moving mechanism has a failure, it is a case where the seat cassette 10 is in the third state.

When the control unit 6 determines in step S129 that the pressure plate moving mechanism has a failure, the pressure plate moving mechanism has a failure as in the case of the first embodiment of the control for calculating the number of sheets S. The information to that effect is notified to the outside (S131), and then the motor 40 is stopped (S133) to end the update process S100 of the number of sheets S.

Further, the update process S200 of the number of sheets S in the present embodiment is performed as follows.
In the image forming apparatus 1 when the power is turned on, the power supply circuit SC receives the clock pulse signal from the clock pulse signal output unit 96, and the sheet cassette 10 is in any of the above-mentioned first to fifth states. It is in that state.
When the sheet cassette 10 is in the first state, the second state, or the third state, the pressure plate 12 is displaced to the first position, and the pressure plate 12 and the first end 14a of the first elastic member 14 are separated from each other. When the power of the image forming apparatus 1 is turned on, power is supplied to the seat sensor 9 in synchronization with the clock pulse signal, and the seat sensor 9 intermittently outputs the first signal.

When the sheet cassette 10 is in the fourth state, the pressure plate 12 moves upward and the seat sensor 9 detects the sheet 18 supported by the pressure plate 12, and the image forming apparatus 1 is powered on. At that point, the seat sensor 9 continuously outputs the second signal.
When the seat cassette 10 is in the fifth state, the pressure plate 12 moves to the uppermost position, the switch SW is closed, and the seat 18 is not detected by the seat sensor 9, so that the image forming apparatus 1 When the power is turned on, the seat sensor 9 continuously outputs the first signal.

As shown in FIG. 27, when the image forming apparatus 1 is powered on (S201), the control unit 6 determines whether or not the seat sensor 9 intermittently outputs the first signal (S204). ..
When the control unit 6 determines in step S204 that the seat sensor 9 does not output the first signal intermittently, the control unit 6 determines whether or not the seat sensor 9 continuously outputs the first signal. (S206).
When the control unit 6 determines in step S206 that the seat sensor 9 continuously outputs the first signal, the control unit 6 determines that the seat cassette 10 is in the fifth state, and as shown in FIG. After displaying "no sheet" on the display unit of the image forming apparatus 1 (S257), the update process S200 of the number of sheets S is terminated.

When the control unit 6 determines in step S206 that the seat sensor 9 does not continuously output the first signal, the seat 18 is supported by the pressure plate 12, and the seat cassette 10 can be inserted and removed when the power is turned off. It is determined that it was not performed (S209). That is, it is determined that the sheet cassette 10 is in the fourth state.
In this case, as in the case of the first embodiment of the control for calculating the number of sheets S, the number of sheets held in the control unit 6 before the power is turned off without updating the number of sheets S. Continue to use S (S211).
After that, the control unit 6 determines that the print preparation is completed (S213), stops the motor 40 (S215), and ends the update process S200 for the number of sheets S.

On the other hand, when the seat sensor 9 determines in step S204 that the first signal is intermittently output, the control unit 6 starts the motor 40 (S221).
When the control unit 6 determines in step S204 that the seat sensor 9 intermittently outputs the first signal, the seat cassette 10 is in the first state, the second state, or the third state. be.

When the motor 40 is started, the push-up plate 13 is rotated upward by the driving force from the motor 40, and the upward movement of the pressure plate 12 is started (S223).
After starting the motor 40, the control unit 6 determines whether or not the seat sensor 9 continuously outputs the first output signal (S226).

When the control unit 6 determines in step S226 that the seat sensor 9 continuously outputs the first output signal, the control unit 6 is currently performing the same as in the case of the first embodiment of the control for calculating the number of sheets S. The number of sheets S held in the control unit 6 is reset to 0 (S227), and the value of the counter C provided in the control unit 6 for measuring the rotation speed of the motor 40 is reset to 0 (S229). The control unit 6 further starts incrementing the counter C and starts measuring the rotation speed of the motor 40 (S231).

After the control unit 6 starts measuring the rotation speed of the motor 40, steps S241 to S255 and S300 are performed as in the case of the first embodiment of the control for calculating the number of sheets S (see FIG. 21). ).
However, the determination of whether or not the seat sensor 9 outputs the second signal, which is performed in step S241, is more specifically whether or not the seat sensor 9 continuously outputs the second signal, that is, whether or not the seat sensor 9 outputs the second signal. , It is determined whether or not the seat sensor 9 has switched from the state of continuously outputting the first signal to the state of continuously outputting the second signal.

On the other hand, when the control unit 6 determines in step S226 that the seat sensor 9 does not continuously output the first output signal, the control unit 6 starts the motor 40 and starts moving the pressing plate 13 upward. It is determined whether or not the predetermined time has elapsed (S234).
If the control unit 6 determines in step S234 that the predetermined time has not elapsed, the control unit 6 executes step S226 again.

Further, when the control unit 6 determines in step S234 that the predetermined time has elapsed, it determines that the pressure plate moving mechanism has a failure, such as the pressure plate 12 not moving upward (S235). ).
That is, if the seat sensor 9 does not continuously output the first output signal even after a predetermined time has elapsed from the time when the motor 40 is started and the pressing plate 13 starts moving upward, the motor 40 is turned on. Since the light emitting unit 92a of the seat sensor 9 does not continuously emit light due to reasons such as the pressure plate 12 not normally moving upward even when started and the switch SW not switching to the closed state, the control unit 6 Determines that the pressure plate moving mechanism has failed.
In this way, when the control unit 6 determines that the pressure plate moving mechanism has a failure, it is a case where the seat cassette 10 is in the third state.

When the control unit 6 determines in step S235 that the pressure plate moving mechanism has a failure, the pressure plate moving mechanism has a failure as in the case of the first embodiment of the control for calculating the number of sheets S. The information to that effect is notified to the outside (S237), and then the motor 40 is stopped (S239) to end the update process S200 of the number of sheets S.

As described above, in the case of the present embodiment, the control unit 6 can receive the first signal and the second signal output from the seat sensor 9, and displaces the push-up plate 13 by controlling the drive unit 4. Before moving the pressure plate 12 upward, the first signal is intermittently received from the seat sensor 9 in response to the clock pulse signal received by the power supply circuit SC, and the drive unit 4 is pressed. When the plate 13 is controlled to move upward, if the first signal is not continuously received from the seat sensor 9 even after a predetermined time has elapsed from the time when the pressing plate 13 starts moving upward, It is configured to notify you of a failure.

This makes it possible to detect whether or not a failure has occurred in the pressure plate moving mechanism before calculating the number of sheets 18 supported on the pressure plate 12 based on the amount of movement of the pressure plate 12 upward. It has become.
In particular, the power supply circuit SC is configured to supply power to the light emitting unit 92a of the sheet sensor 9 by receiving the clock pulse signal output from the clock pulse signal output unit 96 included in the sheet carrier device. The configuration of the control unit 6 can be simplified as compared with the case where the control unit 6 is configured to transmit the power supply command to the light emitting unit 92a of the seat sensor 9 to the power supply circuit SC.

Further, in the present embodiment, the control unit 6 can receive the rotation pulse signal, and when the push-up plate 13 is displaced and the pressure plate 12 is moved upward by controlling the drive unit 4, the seat sensor 9 is used. From the time when the state of intermittently receiving the first signal is switched to the state of continuously receiving the first signal, the measurement of the number of rotation pulse signals received from the rotation pulse signal output unit 95 is started, and then the measurement is started. , When the state in which the first signal is continuously received from the seat sensor 9 is switched to the state in which the second signal is continuously received, the measurement of the number of rotation pulse signals is completed, and the measured number of rotation pulse signals is reached. Based on this, the sheet loading height H corresponding to the amount of movement of the pressure plate 12 upward is calculated.

This makes it possible to reduce the calculation error when calculating the number of sheets S. Further, when the seat loading height H is calculated based on the number of rotation pulse signals to obtain the number of sheets S on the pressure plate 12, the signal received from the seat sensor 9 is used to start the movement of the pressure plate 12 upward. Therefore, it is not necessary to use a dedicated sensor, and it is possible to simplify the device configuration and suppress the cost increase.

[Effect in this embodiment]
In the present embodiment, the image forming apparatus 1 is configured as described above.
That is, the sheet transport device included in the image forming apparatus 1 includes a cassette main body 11, a pressure plate 12, a push-up plate 13, a sheet cassette 10 having a first elastic member 14, and a second elastic member 15, a main body housing 2, and a sheet. It includes a cassette accommodating unit 2a, a first electrode 26, a second electrode 27, a seat transport unit 20, a drive unit 4, a seat sensor 9, a control unit 6, and a power supply circuit SC. The control unit 6 can receive the first signal and the second signal output from the seat sensor 9, can transmit a supply command to the power supply circuit SC, and controls the drive unit 4 to control the push-up plate 13. When the first signal is received from the seat sensor 9 in response to the transmission of the supply command to the power supply circuit SC before the pressure plate 12 is moved upward by displacement, and the transmission of the supply command is transmitted. When the drive unit 4 is controlled to move upward while stopping, the seat sensor 9 is the first even after a predetermined time has elapsed from the time when the transmission of the supply command to the power supply circuit SC is stopped. If no signal is received, a failure is notified.

This makes it possible to detect whether or not a failure has occurred in the pressure plate moving mechanism before calculating the number of sheets S based on the amount of movement of the pressure plate 12 upward.

Further, the sheet transfer device includes a rotation pulse signal output unit 95 that outputs a rotation pulse signal indicating the rotation amount of the motor 40, and the control unit 6 can receive the rotation pulse signal and controls the drive unit 4. When the push-up plate 13 is displaced and the pressure plate 12 is moved upward, the rotation pulse received from the rotation pulse signal output unit 95 from the time when the signal received from the seat sensor 9 is switched from the second signal to the first signal. The measurement of the number of signals is started, and then when the signal received from the seat sensor 9 is switched from the first signal to the second signal, the measurement of the number of rotation pulse signals is finished, and based on the measured number of rotation pulse signals. , The amount of movement of the pressure plate 12 to the upper side is calculated.

This makes it possible to reduce the calculation error when calculating the number of sheets S. Further, when the seat loading height H is calculated based on the number of rotation pulse signals to obtain the number of sheets S on the pressure plate 12, the signal received from the seat sensor 9 is used to start the movement of the pressure plate 12 upward. Therefore, it is not necessary to use a dedicated sensor, and it is possible to simplify the device configuration and suppress the cost increase.

Further, the sheet transport device includes a cassette main body 11, a pressure plate 12, a push-up plate 13, a first elastic member 14, a sheet cassette 10 having a second elastic member 15, a main body housing 2, a sheet cassette accommodating portion 2a, and the like. It includes a first electrode 26, a second electrode 27, a seat transport unit 20, a drive unit 4, a seat sensor 9, a clock pulse signal output unit 96, a control unit 6, and a power supply circuit SC. The control unit 6 can receive the first signal and the second signal output from the seat sensor 9, and before the push-up plate 13 is displaced and the pressure plate 12 is moved upward by controlling the drive unit 4. , When the first signal is intermittently received from the seat sensor 9 in response to the clock pulse signal received by the power supply circuit SC, and the drive unit 4 is controlled to move the pressing plate 13 upward. Occasionally, if the first signal is not continuously received from the seat sensor 9 even after a predetermined time has elapsed from the time when the pressing plate 13 starts moving upward, a failure is notified.

This makes it possible to detect whether or not a failure has occurred in the pressure plate moving mechanism before calculating the number of sheets S based on the amount of movement of the pressure plate 12 upward.
In particular, the power supply circuit SC is configured to supply power to the light emitting unit 92a of the sheet sensor 9 by receiving the clock pulse signal output from the clock pulse signal output unit 96 included in the sheet carrier device. The configuration of the control unit 6 can be simplified as compared with the case where the control unit 6 is configured to transmit the power supply command to the light emitting unit 92a of the seat sensor 9 to the power supply circuit SC.

Further, the sheet transfer device includes a rotation pulse signal output unit 95 that outputs a rotation pulse signal indicating the rotation amount of the motor 40, and the control unit 6 can receive the rotation pulse signal and controls the drive unit 4. When the push-up plate 13 is displaced and the pressure plate 12 is moved upward, the state in which the first signal is intermittently received from the seat sensor 9 is switched to the state in which the first signal is continuously received. , A state in which measurement of the number of rotation pulse signals received from the rotation pulse signal output unit 95 is started, and then a second signal is continuously received from a state in which the first signal is continuously received from the seat sensor 9. When switched to, the measurement of the number of rotation pulse signals is completed, and the amount of movement of the pressure plate 12 upward is calculated based on the measured number of rotation pulse signals.

This makes it possible to reduce the calculation error when calculating the number of sheets S. Further, when the seat loading height H is calculated based on the number of rotation pulse signals to obtain the number of sheets S on the pressure plate 12, the signal received from the seat sensor 9 is used to start the movement of the pressure plate 12 upward. Therefore, it is not necessary to use a dedicated sensor, and it is possible to simplify the device configuration and suppress the cost increase.

Further, the sheet cassette 10 can be displaced between the accommodation position housed in the main body housing 2 and the separation position separated from the main body housing 2, and when the sheet cassette 10 is in the separation position, the pressure plate is 12 is displaced to the first position.

As a result, for example, when the sheet cassette 10 is pulled out from the accommodating position to the separated position and returned to the accommodating position, the pressure plate 12 and the first end 14a of the first elastic member 14 are surely brought into contact with each other. After detecting that the 1st electrode 26 and the 2nd electrode 27 are electrically connected, it is possible to calculate the amount of rise of the pressure plate 12 based on the rotation speed of the motor 40.

Further, the second end 14b of the first elastic member 14 slidably contacts the first electrode 26 in the displacement direction of the sheet cassette 10, and the second end 15b of the second elastic member 15 is the second electrode. The sheet cassette 10 is slidably contacted with respect to 27 in the displacement direction.
As a result, when the sheet cassette 10 is in the accommodation position, the first elastic member 14 and the first electrode 26, and the second elastic member 15 and the second electrode 27 can be surely brought into contact with each other, while the sheet cassette 10 can be brought into contact with each other. When the first elastic member 14 and the first electrode 26 are displaced from the accommodation position to the separated position, the connection between the second elastic member 15 and the second electrode 27 can be easily released.

Further, the seat cassette accommodating portion 2a is provided with a rail 201a for guiding the seat cassette 10, the first electrode 26 is a plate-shaped member arranged on the rail 201a, and the second electrode 27 is the sheet cassette accommodating portion 2a. It is a frame placed at the bottom.
As a result, the first electrode 26 and the second electrode 27 can be arranged without complicating the device configuration, and the miniaturization of the sheet transfer device is not hindered.

Further, the first elastic member 14 comes into contact with the edge portion 12b of the pressure plate 12.
As a result, the first elastic member 14 and the pressure plate 12 can be reliably brought into contact with each other, and the first elastic member 14 and the pressure plate 12 can be stably and electrically connected to each other.

The pressure plate 12 is coated with the conductive grease 121, and the push-up plate 13 comes into contact with the portion of the pressure plate 12 to which the conductive grease 121 is applied.
By applying the conductive grease 121 to the portion of the pressure plate 12 in contact with the push-up plate 13, the pressure plate 12 and the push-up plate 13 can be stably and electrically connected to each other.

1 Image forming device 2 Main body housing 2a Seat cassette accommodating unit 4 Drive unit 6 Control unit 9 Seat sensor 10 Seat cassette 11 Cassette main body 11c Rib 12 Pressure plate 13 Push-up plate 14, 16 First elastic member 14a, 16a First end 14b, 16b 2nd end 15 2nd elastic member 15a 1st end 15b 2nd end 18 Sheet 20 Sheet transport section 26, 28 1st electrode 27 2nd electrode 40 Motor 41 Transmission mechanism 95 Rotation pulse signal output section 96 Clock pulse signal output section 121 Conductive grease

Claims (10)

The first housing that houses the seat and
It is provided in the first housing, supports the seat, and is configured to be movable between a first position which is the lowest position and a second position which is a position above the first position. A pressure plate made of conductor and
A conductor push-up plate provided in the first housing and moving the pressure plate between the first position and the second position while always in contact with the pressure plate.
Provided in the first housing
The first end separates from the pressure plate when the pressure plate is in the first position, and contacts the pressure plate when the pressure plate moves from the first position to the second position.
The second end projects out of the first housing.
The first elastic member made of conductor and
Provided in the first housing
The first end follows the displacement of the push-up plate and comes into contact with the push-up plate.
The second end projects out of the first housing,
The second elastic member made of conductor and
With a sheet cassette,
With the second housing
A seat cassette accommodating portion provided in the second housing and accommodating the sheet cassette,
A first electrode provided in the sheet cassette accommodating portion and in contact with the second end of the first elastic member when the sheet cassette is accommodated in the sheet cassette accommodating portion.
A second electrode provided in the sheet cassette accommodating portion and in contact with the second end of the second elastic member when the sheet cassette is accommodated in the sheet cassette accommodating portion.
A sheet transport unit provided in the second housing and transporting the sheet,
Provided in the second housing
The motor that supplies the driving force and
It has a transmission mechanism that transmits the driving force output by the motor to the push-up plate when the seat cassette is housed in the seat cassette accommodating portion.
A drive unit that displaces the push-up plate and
A sheet sensor that detects that the sheet connected to the first electrode and supported by the pressure plate has reached a predetermined position by moving upward of the pressure plate.
A light emitting element that is a light source that emits light when a power is supplied, a light receiving element that receives and detects light emitted from the light emitting element, and an actuator that contacts and displaces the sheet, and is in contact with the sheet. When it is used, it is located between the light emitting element and the light receiving element to block the light emitted from the light emitting element, and when it does not come into contact with the sheet, it is not located between the light emitting element and the light receiving element and is not located between the light emitting element and the light emitting element. It has an actuator that does not block the emitted light,
When the light emitting element is supplied with electric power and the actuator is not located between the light emitting element and the light receiving element, the light receiving element outputs a first signal.
When the light emitting element is supplied with electric power and the actuator is located between the light emitting element and the light receiving element, the light receiving element outputs a second signal.
When the light emitting element is not supplied with electric power, the light receiving element outputs the second signal.
With the seat sensor
Control unit and
A power supply circuit that supplies power to the light emitting element of the seat sensor.
When the first electrode and the second electrode are not electrically connected due to the separation of the pressure plate and the first end of the first elastic member.
When receiving a supply command from the control unit, power is supplied to the light emitting element to supply electric power.
When the supply command is not received from the control unit, power is not supplied to the light emitting element, and the power is not supplied to the light emitting element.
When the first electrode and the second electrode are electrically connected by contact between the pressure plate and the first end of the first elastic member, the light emission is emitted regardless of the presence or absence of the supply command. Powering the element,
Power supply circuit and
It is a sheet transfer device provided with
The control unit
It is possible to receive the first signal and the second signal,
The supply command can be transmitted to the power supply circuit.
The first signal is received from the seat sensor in response to the transmission of the supply command to the power supply circuit before the push-up plate is displaced by controlling the drive unit to move the pressure plate upward. In this case, the transmission of the supply command is stopped and the push-up plate is moved upward to control the pressure plate and the first end of the first elastic member to come into contact with each other. If the first signal is not received from the seat sensor even after a predetermined time has elapsed from the time when the transmission of the supply command to the power supply circuit is stopped, a failure is notified.
A sheet transfer device characterized by this. A rotation pulse signal output unit for outputting a rotation pulse signal indicating the amount of rotation of the motor is provided.
The control unit
The rotation pulse signal can be received and
When the push-up plate is displaced by controlling the drive unit to move the pressure plate upward,
From the time when the signal received from the seat sensor is switched from the second signal to the first signal, the measurement of the number of the rotation pulse signals received from the rotation pulse signal output unit is started.
Quit number of measurement of the signal received from the previous SL seat sensor is switched to the second signal from the first signal the rotation pulse signal,
The amount of movement of the pressure plate upward is calculated based on the measured number of rotation pulse signals.
The sheet transport device according to claim 1. It is equipped with a clock pulse signal output unit that outputs a clock pulse signal at regular intervals.
The power supply circuit
The clock pulse signal can be received and
When the first electrode and the second electrode are not electrically connected due to the separation of the pressure plate and the first end of the first elastic member.
When the clock pulse signal is received, power is supplied to the light emitting element in synchronization with the clock pulse signal to cause the light emitting element to emit light intermittently.
When the clock pulse signal is not received, power is not supplied to the light emitting element, and the power is not supplied to the light emitting element.
When the first electrode and the second electrode are electrically connected by contact between the pressure plate and the first end of the first elastic member, electric power is supplied to the light emitting element.
The control unit
Before the push-up plate is displaced by controlling the drive unit to move the pressure plate upward, the first signal is intermittently transmitted from the seat sensor in response to the clock pulse signal received by the power supply circuit. When the drive unit is moved upward by moving the push-up plate so that the pressure plate and the first end of the first elastic member come into contact with each other, the push-up plate is received. If the first signal is not continuously received from the seat sensor even after a predetermined time has elapsed from the time when the movement to the upper side of the above is started, a failure is notified.
The sheet transport device according to claim 1. A rotation pulse signal output unit for outputting a rotation pulse signal indicating the amount of rotation of the motor is provided.
The control unit
The rotation pulse signal can be received and
When the push-up plate is displaced by controlling the drive unit to move the pressure plate upward,
The number of the rotation pulse signals received from the rotation pulse signal output unit from the time when the state of intermittently receiving the first signal from the seat sensor is switched to the state of continuously receiving the first signal. Start measuring,
Quit number of measurements with switched from a state in which receiving continuously the first signal from the previous SL seat sensor to a state of receiving continuously said second signal said rotational pulse signal,
The amount of movement of the pressure plate upward is calculated based on the measured number of rotation pulse signals.
The sheet transport device according to claim 3, wherein the sheet transport device is characterized by this. The seat cassette can be displaced between a storage position housed in the second housing and a separation position separated from the second housing.
When the sheet cassette is in the separated position, the pressure plate is displaced to the first position.
The sheet transport device according to any one of claims 1 to 4, wherein the sheet transport device is characterized by this. The second end of the first elastic member slidably contacts the first electrode in the displacement direction of the seat cassette.
The second end of the second elastic member slidably contacts the second electrode in the displacement direction of the seat cassette.
The sheet transport device according to claim 5, wherein the sheet transport device is characterized by this. The seat cassette accommodating portion is provided with a rail for guiding the seat cassette.
The first electrode is a plate-shaped member arranged on the rail, and is
The second electrode is a frame arranged in the lower part of the sheet cassette accommodating portion.
The sheet transport device according to any one of claims 1 to 6, wherein the sheet transport device is characterized by this. The first elastic member comes into contact with the edge of the pressure plate.
The sheet transport device according to any one of claims 1 to 7, wherein the sheet transport device is characterized by this. The pressure plate is coated with conductive grease, and the push-up plate comes into contact with the portion of the pressure plate to which the conductive grease is applied.
The sheet transport device according to any one of claims 1 to 8, wherein the sheet transport device is characterized by this. The sheet transport device according to any one of claims 1 to 9,
An image forming unit provided in the second housing and forming an image on the sheet conveyed from the sheet conveying device by the sheet conveying unit.
To prepare
An image forming apparatus characterized in that.

Images