JP7512841B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming device equipped with a drawer that holds cartridges.

Conventionally, there is known an image forming device that includes a cartridge having a memory, a drawer to which the cartridge can be detached, and a main housing that movably supports the drawer (see Patent Document 1). Specifically, in this technology, the drawer includes a drawer-side connector that is electrically connected to the memory, and the main housing includes a housing-side connector to which the drawer-side connector is connected. When the drawer is pulled out from the image forming position, the drawer-side connector is disengaged from the housing-side connector.

JP 2020-052340 A

The inventors of the present application are currently investigating whether it is possible to determine whether the drawer has been pulled out from the image formation position by utilizing the connection state of the drawer-side connector and the housing-side connector. However, memory is a semiconductor, and if the connectors are disconnected while power is being supplied, there is a risk of data corruption. Furthermore, when power is not being supplied to the memory, the control unit cannot determine whether the connectors have been disconnected, and therefore cannot determine whether the drawer has been pulled out.

The present invention aims to protect passive elements such as memory installed in the cartridge, while using the connection state between the drawer side connector and the housing side connector to determine whether the drawer has been pulled out from the image formation position.

In order to solve the above problem, the image forming apparatus of the present invention comprises a main housing, a cover for opening and closing an opening of the main housing, a drawer for holding a cartridge having a memory and capable of being pulled out from an image forming position of the main housing through the opening to the outside of the main housing, a temperature sensor provided in the drawer, a drawer side connector provided in the drawer and conductive with the memory and the temperature sensor, a control unit provided in the main housing, and a housing side connector provided in the main housing and conductive with the control unit.
The drawer-side connector and the housing-side connector are in contact with each other when the drawer is in the image forming position, and are separated from each other when the drawer is pulled out from the image forming position.
The control unit stops power supply to the memory when the cover is opened, and determines that the drawer has been pulled out from the image forming position when no signal is obtained from the temperature sensor.

According to this configuration, by stopping the flow of power to the memory when the cover is opened, even if the drawer is pulled out and the connectors are disconnected after the cover is opened, the memory can be protected because the power to the memory is stopped. Also, when the drawer is pulled out, the connectors are disconnected and a signal cannot be obtained from the temperature sensor, so the control unit can use the connection state of each connector to determine whether the drawer has been pulled out. As for the temperature sensor, even if the connectors are disconnected while power is being supplied, there is no problem with data corruption and it can continue to be used without problems thereafter.

The drawer may include a photoreceptor, and the main body housing may include a transfer device in contact with the photoreceptor, and the control unit may determine that a jam error has occurred when a sheet remains between the photoreceptor and the transfer device, and may clear the jam error based on determining that the drawer has been pulled out from the image forming position.

With this configuration, the jam error will not be cleared unless the drawer is pulled out, which prevents printing from starting with the sheet remaining between the photoconductor and the transfer device.

The control unit may also clear the jam error based on determining that a predetermined time or more has elapsed since the drawer was pulled out of the image forming position.

It takes a certain amount of time to remove a sheet that has become stuck between the photoconductor and the transfer device, so by setting the condition for clearing the jam error to the amount of time that has elapsed since the drawer was pulled out, it is possible to further prevent printing from starting with a sheet remaining between the photoconductor and the transfer device.

The control unit may also clear the jam error based on a change in impedance between the photoconductor and the transfer device before the drawer is pulled out from the image forming position and after the drawer is pulled out from the image forming position.

The impedance between the photoconductor and the transfer device is different when there is a sheet between the photoconductor and the transfer device and when there is not. Therefore, by making the change in impedance a condition for clearing the jam error, it is possible to further prevent printing from starting with a sheet remaining between the photoconductor and the transfer device.

The control unit may also determine that the drawer is positioned at the image forming position when a signal is obtained from the temperature sensor after a state in which a signal is not obtained from the temperature sensor.

When the drawer is placed in the image formation position, the connectors are connected and the temperature sensor goes from not receiving a signal to receiving one, so the control unit can use the connection state of each connector to determine whether the drawer is placed in the image formation position.

The control unit may also start energizing the memory when the drawer is placed in the image forming position and the cover is closed.

For example, in a configuration in which power to the memory begins when the drawer is placed in the image formation position, if the drawer is pulled out of the image formation position immediately after being placed in the image formation position, power to the memory may be forcibly cut off, which may result in data corruption. In contrast, in the configuration described above, power to the memory begins to flow only after the cover is closed and the drawer cannot be pulled out, so the memory can be protected.

The cartridge may also have a storage section for storing developer and be detachable from the drawer.

With this configuration, when the drawer is pulled out of the main body housing to install or remove the cartridge, power to the memory is cut off, protecting the memory.

The drawer may also include a drawer memory, the drawer-side connector may be electrically connected to the drawer memory, and the control unit may stop powering the drawer memory when the cover is opened.

According to this configuration, by cutting off power to the drawer memory when the cover is opened, even if the drawer is pulled out after the cover is opened and the connectors are disconnected, power to the drawer memory is cut off, so the drawer memory can be protected.

In addition, the image forming apparatus of the present invention comprises a main housing, a cover for opening and closing an opening of the main housing, a drawer for holding a cartridge having a semiconductor element and capable of being pulled out from an image forming position of the main housing through the opening to the outside of the main housing, a passive element provided in the drawer, a drawer side connector provided in the drawer and conductive with the semiconductor element and the passive element, a control unit provided in the main housing, and a housing side connector provided in the main housing and conductive with the control unit.
The drawer-side connector and the housing-side connector are in contact with each other when the drawer is in the image forming position, and are separated from each other when the drawer is pulled out from the image forming position.
The control unit stops power supply to the semiconductor element when the cover is opened, and determines that the drawer has been pulled out from the image forming position when no signal is obtained from the passive element.

According to this configuration, by stopping the flow of electricity to the semiconductor element when the cover is opened, even if the drawer is pulled out and the connectors are disconnected after the cover is opened, the semiconductor element is protected because the flow of electricity to the semiconductor element is stopped. Furthermore, when the drawer is pulled out, the connectors are disconnected and signals cannot be obtained from the passive elements, so the control unit can use the connection state of each connector to determine whether the drawer has been pulled out. Furthermore, with regard to the passive elements, even if the connectors are disconnected while power is being supplied, there is no problem with data corruption or the like, and they can continue to be used without problems thereafter.

The passive element may also be a resistive element.

The resistive element may also be a thermistor whose resistance value changes with temperature.

According to the present invention, it is possible to determine whether the drawer has been pulled out from the image formation position by utilizing the connection state between the drawer side connector and the housing side connector while protecting passive elements such as memory provided in the cartridge.

FIG. 1 illustrates a configuration of a color printer. FIG. FIG. 1 is a block diagram showing the electrical connections between the controller, the drawer circuit board, and the four toner circuit boards. 4 is a flowchart showing a printing process. 10 is a flowchart showing a jam error determination process. 13 is a flowchart showing an error release process. 13 is a flowchart showing a modified example of the error cancellation process.

Next, an embodiment of the present invention will be described in detail with reference to the drawings as appropriate.
As shown in FIG. 1, a color printer 1, which is an example of an image forming apparatus, includes a main body housing 10, a supply section 20 that supplies a sheet P, an image forming section 30 that forms an image on the sheet P, a conveying section 90 that ejects the sheet P on which the image has been formed, and a control section 100.

The main body housing 10 has an opening 10A and a cover 11 that opens and closes the opening 10A. The opening 10A is an opening through which a unit U, which will be described later, can pass. The cover 11 is rotatable between an open position that opens the opening 10A and a closed position that closes the opening 10A.

The supply unit 20 includes a supply tray 21 that stores sheets P, and a sheet transport mechanism 22 that transports the sheets P from the supply tray 21 to the image forming unit 30.

The image forming unit 30 includes a scanner unit 40, a unit U, a transfer device 70, and a fixing device 80.

The scanner unit 40 includes a laser emitter, a polygon mirror, a lens, and a reflector (not shown). The scanner unit 40 irradiates the surface of each photosensitive drum 61 with a laser beam.

The unit U can be pulled out from the main body housing 10 through the opening 10A. The unit U includes four cartridges 50 and a drawer 60.

The cartridges 50 are detachably attached to the drawer 60. The cartridges 50 are equipped with a storage section 51 that stores toner as an example of a developer, a developing roller 52, a layer thickness regulating blade 53 that contacts the developing roller 52 to regulate the layer thickness of the toner on the developing roller 52, and a memory M1 as an example of a semiconductor element. The storage sections 51 of the four cartridges 50 store toner of each of the colors yellow, magenta, cyan, and black.

The cartridges 50 are indicated by the reference characters 50Y, 50M, 50C, and 50K, containing toner of each color, yellow, magenta, cyan, and black, and are arranged in that order from upstream in the conveying direction of the sheet P. The memory M1 stores information about the life of the cartridge 50, such as the remaining amount of toner.

The drawer 60 is a member that holds each cartridge 50. The drawer 60 can be pulled out from the image forming position of the main body housing 10 through the opening 10A to the outside of the main body housing 10 in a direction perpendicular to the up-down direction. The drawer 60 can move between an image forming position where each cartridge 50 is located inside the main body housing 10 and an exchange position where each cartridge 50 is exposed to the outside of the main body housing 10. Here, the image forming position refers to the position of the drawer 60 when image formation is performed. The exchange position refers to the position of the drawer 60 when replacing each cartridge 50. The drawer 60 includes a photosensitive drum 61 as an example of a photosensitive body, a charger (not shown), a frame 62 that detachably holds the four cartridges 50, a temperature sensor SE1 as an example of a passive element, a drawer memory M2, and a drawer side connector CN1. Four photosensitive drums 61 and chargers are provided on the frame 62 corresponding to the four developing rollers 52.

The frame 62 is supported on the main housing 10 so that it can move in a direction perpendicular to the up-down direction. The temperature sensor SE1 is a resistive element. Specifically, the temperature sensor SE1 is a thermistor whose resistance value changes depending on the temperature. The temperature sensor SE1 acquires the internal temperature, which is the temperature inside the main housing 10. The drawer memory M2 stores information related to the life of the photosensitive drum 61, such as the total number of rotations of the photosensitive drum 61.

The drawer-side connector CN1 is electrically connected to the temperature sensor SE1, memory M1, and drawer memory M2 via wiring. As shown in FIG. 3, the memory M1 of each cartridge 50 is electrically connected to the drawer-side connector CN1 by connecting the connector CN3 provided on each cartridge 50 to the connector CN4 provided on the drawer 60.

Returning to FIG. 1, the main housing 10 includes a control unit 100 and a housing-side connector CN2 that is electrically connected to the control unit 100 via wiring. The drawer-side connector CN1 is connected to the housing-side connector CN2 when the drawer 60 is placed in the image formation position of the main housing 10. In more detail, when the drawer 60 is placed in the image formation position, the drawer-side connector CN1 comes into contact with the housing-side connector CN2.

Also, as shown in FIG. 2, when the drawer 60 is pulled out from the main housing 10 and placed in the replacement position, the drawer side connector CN1 is separated from the housing side connector CN2. More specifically, when the drawer 60 is pulled out from the image formation position and placed in the separation position between the image formation position and the replacement position, the drawer side connector CN1 is separated from the housing side connector CN2. The separation position is a position where each cartridge 50 is located inside the main housing 10, and where image formation cannot be performed.

Returning to FIG. 1, the transfer device 70 includes a drive roller 71, a driven roller 72, a conveyor belt 73, and a transfer roller 74. The conveyor belt 73 is an endless belt. The drive roller 71 and the driven roller 72 are rollers that rotate the conveyor belt 73. The transfer rollers 74 are rollers that hold the conveyor belt 73 between themselves and the corresponding photosensitive drums 61, and four of them are arranged opposite each photosensitive drum 61. The transfer device 70 is arranged so that the upper surface of the conveyor belt 73 is in contact with each photosensitive drum 61.

The fixing device 80 is a device that fixes the toner image onto the sheet P. The fixing device 80 includes a heating roller 81 that is heated by a heater H, and a pressure roller 82 that is pressed against the heating roller 81.

When the drawer 60 is in the image formation position of the main body housing 10, the color printer 1 is capable of image formation. The image formation position is a position where the photosensitive drum 61 and the transfer device 70 are in contact with each other, and where the scanner unit 40 can expose a predetermined position of the photosensitive drum 61. In the image forming section 30, the surface of each photosensitive drum 61 is first uniformly charged by the charger, and then exposed by the scanner unit 40. As a result, an electrostatic latent image based on image data is formed on each photosensitive drum 61. Thereafter, the developing roller 52 supplies toner in the storage section 51 to the electrostatic latent image on the photosensitive drum 61, forming a toner image on the photosensitive drum 61.

Next, the sheet P fed onto the conveyor belt 73 passes between each photosensitive drum 61 and each transfer roller 74, so that the toner images formed on each photosensitive drum 61 are transferred onto the sheet P. Then, the sheet P passes between the heating roller 81 and the pressure roller 82, so that the toner images transferred onto the sheet P are thermally fixed.

The transport unit 90 functions as a discharge mechanism that discharges the sheet P discharged from the image forming unit 30 onto the discharge tray 13 of the main body housing 10, and also functions as a re-transport means that re-transports the sheet P, one side of which has an image formed by the image forming unit 30, to the image forming unit 30 in a state in which the sheet P is turned over. Specifically, the transport unit 90 mainly includes a transport path 91, a discharge roller 92, and a re-transport path 93.

The transport path 91 is a path that guides the sheet P from the fixing device 80 toward the discharge tray 13.

The discharge roller 92 is configured to be rotatable in both forward and reverse directions. When rotating forward, it discharges the sheet P discharged from the image forming unit 30 toward the discharge tray 13, and when rotating reverse, it transports the sheet P so that it is drawn into the main body housing 10.

The re-conveying path 93 is configured to guide the sheet P, which has an image formed on one side by the image forming unit 30, back to the image forming unit 30 by passing it under the supply unit 20.

The color printer 1 also includes a cover opening/closing sensor SE2 that detects whether the cover 11 is open or closed, a first sheet sensor SE3, and a second sheet sensor SE4.

When the cover 11 is closed, part of the cover 11 comes into contact with the cover open/close sensor SE2 and outputs an ON signal to the control unit 100. When the cover 11 is open, the cover open/close sensor SE2 moves away from the cover 11 and outputs an OFF signal to the control unit 100.

The first sheet sensor SE3 and the second sheet sensor SE4 are sensors that detect the presence or absence of a sheet. The first sheet sensor SE3 and the second sheet sensor SE4 have, for example, a rocking member that rocks when it comes into contact with the sheet P, and an optical sensor that detects the rocking of the rocking member. In this embodiment, each sheet sensor SE3, SE4 outputs an ON signal when the rocking member is tilted by the sheet P, and outputs an OFF signal when the rocking member is not tilted.

The first sheet sensor SE3 is located upstream of the photosensitive drum 61 in the transport direction of the sheet P. The second sheet sensor SE4 is located downstream of the first sheet sensor SE3, more specifically, downstream of the heating roller 81, in the transport direction of the sheet P.

As shown in FIG. 3, the control unit 100 has a main circuit board 101, a processor 102 such as a CPU, and a main body memory 103 which is a storage medium. The control unit 100 executes various processes by the processor 102 operating according to a program. The drawer 60 has a drawer circuit board 601 which has a drawer memory M2 and a temperature sensor SE1. Each cartridge 50 has a toner circuit board 501 which has a memory M1.

The main circuit board 101 has a main terminal 510. The toner circuit board 501 has a toner terminal 550. The drawer circuit board 601 has a first terminal 520 connected to the main terminal 510 via wiring and connectors CN1 and CN2, four second terminals 530 connected to the respective toner terminals 550 of each cartridge 50 via wiring and connectors CN3 and CN4, and relay wires 540 connecting the first terminal 520 and each second terminal 530.

The main terminals 510 include a main voltage terminal 511, a main ground terminal 512, a main clock terminal 513, five main signal terminals 514, and two main sensor terminals 515. The first terminals 520 include a first voltage terminal 521, a first ground terminal 522, a first clock terminal 523, five first signal terminals 524, and two first sensor terminals 525. When the connectors CN1 and CN2 are connected, the voltage terminals 511 and 521, the ground terminals 512 and 522, the clock terminals 513 and 523, the signal terminals 514 and 524, and the sensor terminals 515 and 525 are electrically connected to each other.

A total of four second terminals 530 are provided, one at a position corresponding to each cartridge 50. The second terminals 530 include a second voltage terminal 531, a second ground terminal 532, a second clock terminal 533, and a second signal terminal 534. The voltage terminals 521, 531, the ground terminals 522, 532, the clock terminals 523, 533, and the signal terminals 524, 534 are electrically connected to each other via relay lines 540.

The first voltage terminal 521, the first ground terminal 522, the first clock terminal 523, and the first signal terminal 524 are electrically connected to the drawer memory M2 via a relay line 540. The first sensor terminal 525 is electrically connected to the temperature sensor SE1 via a wiring.

The toner terminals 550 include a toner voltage terminal 551, a toner ground terminal 552, a toner clock terminal 553, and a toner signal terminal 554. When the connectors CN3 and CN4 are connected, the voltage terminals 531 and 551, the ground terminals 532 and 552, the clock terminals 533 and 553, and the signal terminals 534 and 554 are electrically connected to each other. In addition, the toner voltage terminal 551, the toner ground terminal 552, the toner clock terminal 553, and the toner signal terminal 554 are electrically connected to the memory M1.

The voltage terminals 511, 521, 531, and 551 mentioned above are terminals for supplying a power supply voltage. The ground terminals 512, 522, 532, and 552 are terminals for supplying a ground voltage. The clock terminals 513, 523, 533, and 553 are terminals for supplying a clock signal at regular time intervals. The signal terminals 514, 524, 534, and 554 are terminals for transmitting and receiving signals indicating various information. The sensor terminals 515 and 525 are terminals for passing electricity through the temperature sensor SE1.

The control unit 100 has a function of stopping the power supply to the memories M1 and M2 when the cover 11 is opened, and determining that the drawer 60 has been pulled out from the image forming position when no signal is obtained from the temperature sensor SE1. In more detail, when the control unit 100 determines that the cover 11 is opened based on a signal from the cover opening/closing sensor SE2, it stops the power supply to the memories M1 and M2 by stopping the power supply to the terminals 511 to 514, and continues the power supply to the main sensor terminal 515, thereby continuing the power supply to the temperature sensor SE1. When the connectors CN1 and CN2 are disconnected by pulling out the drawer 60, the control unit 100 is no longer able to obtain a signal from the temperature sensor SE1, and determines that the drawer 60 has been pulled out based on the fact that no signal is obtained. A state in which no signal is obtained from the temperature sensor SE1 is specifically a state in which the resistance value of the temperature sensor SE1, which is a thermistor, exceeds a predetermined range.

The control unit 100 has a function to determine whether a jam error has occurred in which the sheet P stops during printing. In particular, the control unit 100 can determine a first jam error in which the sheet P is jammed near the first sheet sensor SE3, a second jam error in which the sheet P is jammed between the first sheet sensor SE3 and the second sheet sensor SE4, and a third jam error in which the sheet P is jammed near the second sheet sensor SE4.

The control unit 100 determines that a first jam error has occurred when the time during which the ON signal is output from the first sheet sensor SE3 exceeds the sheet length time, that is, when the sheet P is jammed near the first sheet sensor SE3 and the first sheet sensor SE3 remains tilted. Here, the sheet length time is a time corresponding to the length of the sheet P. When the sheet P passes through the first sheet sensor SE3 normally, the first sheet sensor SE3 is ON for the time obtained by dividing the length of the sheet P by the conveying speed of the sheet P, so the sheet length time is set to a time longer than this time.

The control unit 100 determines that a second jam error has occurred when a specific sheet P is not detected by the second sheet sensor SE4 within a specific time after the specific sheet P is detected by the first sheet sensor SE3, that is, when the sheet P passes the first sheet sensor SE3 normally but gets stuck before reaching the second sheet sensor SE4. Therefore, the control unit 100 determines that a second jam error has occurred when a sheet P remains between the photosensitive drum 61 and the transfer device 70.

The control unit 100 determines that a third jam error has occurred if the time during which the ON signal is output from the second sheet sensor SE4 exceeds the sheet length time, that is, if the sheet P is jammed near the second sheet sensor SE4 and the second sheet sensor SE4 remains tilted.

The control unit 100 has a function of clearing a jam error based on the determination that the drawer 60 has been pulled out from the image forming position. More specifically, the control unit 100 has a function of clearing a jam error based on the determination that the time that has elapsed since the drawer 60 was pulled out from the image forming position is equal to or longer than a predetermined time. Here, the predetermined time is set to the minimum time required for the user to remove the sheet P that has become jammed inside the main body housing 10.

In this embodiment, the conditions for clearing the jam error include the aforementioned drawer 60 being pulled out and the elapsed time being equal to or greater than a predetermined time, as well as the conditions for opening and closing the cover 11, the drawer 60 being placed in the image formation position, and each sheet sensor SE3, SE4 being OFF.

The control unit 100 has a function of determining that the drawer 60 is placed in the image formation position when a signal is obtained from the temperature sensor SE1 after a state in which no signal is obtained. In more detail, when the drawer 60 is placed in the image formation position, the connectors CN1 and CN2 are connected and a signal can be obtained from the temperature sensor SE1. Therefore, the control unit 100 determines that the drawer 60 is placed in the image formation position based on the change from a state in which no signal is obtained to a state in which a signal is obtained.

The control unit 100 has the function of starting the supply of electricity to each memory M1, M2 when the drawer 60 is placed in the image forming position and the cover 11 is closed.

Next, the operation of the control unit 100 will be described in detail.
When the control unit 100 receives a print command, it executes the print process shown in FIG.

In the printing process, the control unit 100 first starts printing (S1). After step S1, the control unit 100 executes a jam error determination process (S2). The jam error determination process will be described in detail later.

After step S2, the control unit 100 determines whether a jam error has occurred, more specifically, whether it has been determined in the jam error determination process that a jam error has occurred (S3). If it is determined in step S3 that a jam error has occurred (Yes), the control unit 100 stops printing (S4).

After step S4, the control unit 100 executes an error clearing process (S5). The error clearing process will be described in detail later.

After step S5, the control unit 100 determines whether the jam error has been cleared in the error clearing process (S6). If it is determined in step S6 that the jam error has not been cleared (No), the control unit 100 returns to the process of step S5.

If it is determined in step S6 that the jam error has been cleared (Yes), the control unit 100 resumes printing (S7). After step S7, or if it is determined No in step S3, the control unit 100 determines whether printing has ended (S8).

If it is determined in step S8 that printing has not finished (No), the control unit 100 returns to the process of step S2. If it is determined in step S8 that printing has finished (Yes), the control unit 100 ends this process.

As shown in FIG. 5, in the jam error determination process, the control unit 100 first determines whether the first sheet sensor SE3 is ON (S31). If it is determined in step S31 that the first sheet sensor SE3 is not ON (No), the control unit 100 ends this process.

If it is determined in step S31 that the first sheet sensor SE3 is ON (Yes), the control unit 100 determines whether the ON time of the first sheet sensor SE3 has exceeded the sheet length time (S32). If it is determined in step S32 that the ON time of the first sheet sensor SE3 has exceeded the sheet length time (Yes), the control unit 100 determines that a first jam error has occurred (S33) and ends this process.

If it is determined in step S32 that the ON time of the first sheet sensor SE3 does not exceed the sheet length time (No), the control unit 100 determines whether the first sheet sensor SE3 has turned OFF (S34).

If it is determined in step S34 that the first sheet sensor SE3 is not OFF (No), the control unit 100 returns to the process of step S32. If it is determined in step S34 that the first sheet sensor SE3 is OFF (Yes), the control unit 100 determines whether the second sheet sensor SE4 is ON within a predetermined time after the first sheet sensor SE3 is turned ON (S35).

If it is determined in step S35 that the second sheet sensor SE4 has not turned ON within a predetermined time from when the first sheet sensor SE3 turned ON (No), the control unit 100 determines that a second jam error has occurred (S36) and ends this process. If it is determined in step S35 as Yes, the control unit 100 determines whether the ON time of the second sheet sensor SE4 has exceeded the sheet length time (S37).

If it is determined in step S37 that the ON time of the second sheet sensor SE4 has exceeded the sheet length time (Yes), the control unit 100 determines that a third jam error has occurred (S38) and ends this process. If it is determined in step S37 that the answer is No, the control unit 100 determines whether the second sheet sensor SE4 has turned OFF (S39).

If it is determined in step S39 that the second sheet sensor SE4 is not OFF (No), the control unit 100 returns to the process of step S37. If it is determined in step S39 that the second sheet sensor SE4 is OFF (Yes), the control unit 100 ends this process.

As shown in FIG. 6, in the error clearing process, the control unit 100 first determines whether the cover 11 has been opened based on a signal from the cover open/close sensor SE2 (S61). If it is determined in step S61 that the cover 11 has not been opened (No), the control unit 100 ends this process without clearing the jam error.

If it is determined in step S61 that the cover 11 has been opened (Yes), the control unit 100 stops the flow of power to each of the memories M1 and M2 (S62). After step S62, the control unit 100 determines whether or not the drawer 60 has been pulled out from the image formation position based on the connection state of each of the connectors CN1 and CN2 (S63). More specifically, in step S63, the control unit 100 determines whether or not there is a response from the temperature sensor SE1 provided in the drawer 60, and if there is no response, determines that the drawer 60 has been pulled out from the image formation position. If it is determined in step S63 that the drawer 60 has not been pulled out (No), the control unit 100 ends this process without clearing the jam error.

If it is determined in step S63 that the drawer 60 has been pulled out (Yes), the control unit 100 starts measuring the time that has elapsed since the drawer 60 was pulled out (S64). After step S64, the control unit 100 determines whether or not the drawer 60 has been placed in the image formation position based on the connection state of each connector CN1, CN2 (S65). More specifically, in step S65, the control unit 100 determines whether or not there has been a response from the temperature sensor SE1 provided in the drawer 60, and if there has been a response, determines that the drawer 60 has been placed in the image formation position.

If it is determined in step S65 that the drawer 60 is not positioned at the image formation position (No), the control unit 100 repeats the process of step S65. If it is determined in step S65 that the drawer 60 is positioned at the image formation position (Yes), the control unit 100 determines whether the cover 11 is closed or not based on a signal from the cover open/close sensor SE2 (S66).

If it is determined in step S66 that the cover 11 is not closed (No), the control unit 100 returns to the process of step S65. If it is determined in step S66 that the cover 11 is closed (Yes), the control unit 100 starts supplying power to each of the memories M1 and M2 (S67).

After step S67, the control unit 100 determines whether the time that has elapsed since the drawer 60 was pulled out is equal to or greater than a predetermined time (S68). If it is determined in step S68 that the time that has elapsed is not equal to or greater than the predetermined time (No), the control unit 100 ends this process without clearing the jam error.

If it is determined in step S68 that the elapsed time is equal to or longer than the predetermined time (Yes), the control unit 100 determines whether each sheet sensor SE3, SE4 is OFF, and thereby determines whether the sheet P that is holding the rocking member of the first sheet sensor SE3 or the second sheet sensor SE4 in a tilted position has been removed (S69). Note that the process of step S69 is particularly effective when the first jam error or the third jam error occurs, but it is also effective when the second jam error occurs, because a sheet P other than the sheet P causing the error may be stopped with the rocking member in a tilted position.

If it is determined in step S69 that each sheet sensor SE3, SE4 is OFF (Yes), the control unit 100 clears the jam error (S70), resets the elapsed time (S71), and ends this process. If it is determined in steps S68 and S69 as No, the control unit 100 does not clear the jam error and ends this process.

Next, an example of the operation of the control unit 100 will be described in detail.
If a jam error occurs during printing, the control unit 100 stops printing (S2 to S4 in FIG. 4). When printing is stopped due to a jam error, the user opens the cover 11 as shown in FIG. 1 and FIG. 2. This causes the cover open/close sensor SE2 to output an OFF signal to the control unit 100, so the control unit 100 determines that the cover 11 has been opened and stops the supply of electricity to the memories M1 and M2 (S61 and S62 in FIG. 6).

After that, when the user pulls out the drawer 60 from the image formation position, the drawer side connector CN1 is disconnected from the housing side connector CN2. As a result, the control unit 100 cannot obtain a response from the temperature sensor SE1, so it determines that the drawer 60 has been pulled out from the image formation position and starts measuring the elapsed time (S63, S64).

After pulling out the drawer 60, the user removes the sheets P that are stuck inside the main body housing 10. The time required for the removal operation to remove the sheets P is equal to or longer than a predetermined time. Note that in this example, it is assumed that all sheets P that are stuck inside the main body housing 10 are removed during the removal operation.

When the user removes the sheet P, he or she returns the drawer 60 to the image formation position. This connects the drawer side connector CN1 to the housing side connector CN2, and the control unit 100 is able to obtain a response from the temperature sensor SE1 and determines that the drawer 60 has been placed in the image formation position (S65).

After returning the drawer 60 to the image formation position, the user closes the cover 11. This causes the cover open/close sensor SE2 to output an ON signal to the control unit 100, so the control unit 100 determines that the cover 11 is closed and starts passing electricity to each of the memories M1 and M2 (S66, S67). In other words, the control unit 100 starts passing electricity to each of the memories M1 and M2 after the user is unable to access the drawer 60 due to the cover 11 being closed.

After that, the control unit 100 determines in step S68 that the elapsed time is equal to or greater than the predetermined time (S68: Yes), and then determines that each sheet sensor SE3, SE4 is OFF (S69: Yes), and releases the jam error (S70). Note that if the user pulls out the drawer 60 and then returns the drawer 60 to the image formation position and closes the cover 11 without performing the removal operation, the elapsed time will not be equal to or greater than the predetermined time, so the control unit 100 determines No in step S68 and does not release the jam error. Also, if the sheet P jammed near the first sheet sensor SE3 or the second sheet sensor SE4 is not removed during the removal operation, the control unit 100 determines No in step S69 and does not release the jam error.

As described above, the following effects can be obtained in this embodiment.
By stopping the power supply to the memories M1 and M2 when the cover 11 is opened, even if the drawer 60 is pulled out after the cover 11 is opened and the connectors CN1 and CN2 are disconnected, the memories M1 and M2 can be protected because the power supply to the memories M1 and M2 is stopped. Also, when the drawer 60 is pulled out, the connectors CN1 and CN2 are disconnected and a signal cannot be obtained from the temperature sensor SE1, so the control unit 100 can determine whether the drawer 60 has been pulled out by using the connection state of the connectors CN1 and CN2. Note that even if the connectors CN1 and CN2 are disconnected while power is being supplied to the temperature sensor SE1, there is no problem with data corruption, and the temperature sensor SE1 can be used without problems thereafter.

After a jam error occurs, the jam error will not be cleared unless the drawer 60 is pulled out, so printing can be prevented from starting with the sheet P remaining inside the main body housing 10.

It takes a certain amount of time to remove the jammed sheet P from inside the main body housing 10, so by making the elapsed time since the drawer 60 was pulled out the condition for clearing the jam error, it is possible to further prevent printing from starting with the sheet P remaining inside the main body housing 10.

When the drawer 60 is placed in the image formation position, the connectors CN1 and CN2 are connected and a signal is obtained from the temperature sensor SE1 instead of being received as a signal. Therefore, the control unit 100 can use the connection state of the connectors CN1 and CN2 to determine whether the drawer 60 is placed in the image formation position.

For example, in a configuration in which electricity begins to flow to each of the memories M1 and M2 when the drawer 60 is placed in the image formation position, if the drawer 60 is pulled out of the image formation position immediately after being placed in the image formation position, electricity to each of the memories M1 and M2 may be forcibly cut off, which may result in data corruption. In contrast, in this embodiment, electricity begins to flow to each of the memories M1 and M2 after the cover 11 is closed and the drawer 60 cannot be pulled out, so that each of the memories M1 and M2 can be protected.

When the drawer 60 is pulled out of the main body housing 10 to attach or detach the cartridge 50, power to each of the memories M1 and M2 is stopped, so each of the memories M1 and M2 can be protected.

The present invention is not limited to the above embodiment, but can be used in various forms as exemplified below. In the following description, structures and processes that are substantially similar to those in the above embodiment are given the same reference numerals, and their description will be omitted.

The jam error release conditions are not limited to those in the above embodiment. For example, as shown in FIG. 7, the jam error release conditions may include an impedance condition between the photosensitive drum 61 and the transfer device 70 in addition to the above-mentioned conditions.

Specifically, in this embodiment, the control unit 100 clears the jam error based on the change in impedance before the drawer 60 is pulled out from the image forming position and after the drawer 60 is pulled out from the image forming position. In more detail, the control unit 100 executes the error clearing process shown in FIG. 7. The error clearing process shown in FIG. 7 includes steps S61 to S71 in the error clearing process shown in FIG. 6, as well as new steps S91 to S95.

In the error clearing process shown in FIG. 7, the control unit 100 first determines whether the type of jam error is a second jam error (S91). In other words, in step S91, the control unit 100 essentially determines whether a sheet P is present between the photosensitive drum 61 and the transfer device 70.

If it is determined in step S91 that a second jam error has occurred (Yes), the control unit 100 passes a current between the photosensitive drum 61 and the transfer device 70 to measure the first impedance Z1, which is the impedance during the period from when the second jam error occurs until before the drawer 60 is pulled out from the image forming position (S92). Here, when a sheet P is present between the photosensitive drum 61 and the transfer device 70, the impedance value is larger than when a sheet P is not present.

After step S92, the control unit 100 executes the processes of steps S61 to S68 as appropriate. Also, if it is determined in step S91 that there is no second jam error (No), the control unit 100 executes the processes of steps S61 to S68 as appropriate without measuring the first impedance Z1.

If the determination in step S68 is Yes, the control unit 100 determines whether the type of jam error is a second jam error (S93). If the determination in step S93 is Yes, the control unit 100 measures the second impedance Z2, which is the impedance after the drawer 60 is pulled out from the image forming position (S94).

After step S94, the control unit 100 determines whether the second impedance Z2 is smaller than the first impedance Z1 (S95). Here, when the sheet P between the photosensitive drum 61 and the transfer device 70 is removed by the user, the second impedance Z2 becomes smaller than the first impedance Z1. Therefore, in step S95, the control unit 100 essentially determines whether the sheet P has been removed from between the photosensitive drum 61 and the transfer device 70.

If it is determined in step S95 that Z1>Z2 is not true (No), the control unit 100 ends this process without clearing the second jam error. If it is determined in step S95 that Z1>Z2 is true (Yes), or if it is determined in step S93 that No, the control unit 100 executes the processes of steps S69 to S71 as appropriate.

As described above, according to the embodiment shown in FIG. 7, the change in impedance is set as the condition for clearing the second jam error, which further prevents printing from starting with the sheet P remaining between the photosensitive drum 61 and the transfer device 70.

The semiconductor element is not limited to memories M1 and M2, but may be any semiconductor element. Furthermore, the passive element is not limited to a thermistor, but may be a resistive element other than a thermistor, or may be a passive element other than a resistive element.

In the above embodiment, a photosensitive drum 61 is used as an example of a photosensitive body, but the present invention is not limited to this, and a belt-shaped photosensitive body may also be used.

In the above embodiment, the present invention is applied to a color printer 1, but the present invention is not limited to this, and the present invention may also be applied to other image forming devices, such as copiers and multifunction machines.

The elements described in the above embodiments and variations may be implemented in any combination.

REFERENCE SIGNS LIST 1 color printer 10 main body housing 10A opening 11 cover 50 cartridge 60 drawer 100 control unit CN1 drawer side connector CN2 housing side connector M1 memory SE1 temperature sensor

Claims (9)

A main body housing;
a cover for opening and closing the opening of the main body housing;
a drawer that holds a cartridge having a memory and that can be pulled out from an image forming position of the main body housing through the opening to the outside of the main body housing;
A temperature sensor provided in the drawer;
a drawer side connector provided in the drawer and electrically connected to the memory and the temperature sensor;
A control unit provided in the main body housing;
a housing-side connector provided in the main body housing and electrically connected to the control unit;
the drawer-side connector and the housing-side connector are in contact with each other when the drawer is in the image forming position and are separated from each other when the drawer is pulled out from the image forming position;
The control unit is
When the cover is opened, power supply to the memory is stopped;
When a signal is no longer obtained from the temperature sensor, it is determined that the drawer has been pulled out from the image forming position. The drawer includes a photoreceptor.
the main body housing includes a transfer device in contact with the photoconductor;
The control unit is
determining that a jam error has occurred when a sheet remains between the photoconductor and the transfer device;
2. The image forming apparatus according to claim 1, wherein the jam error is cleared based on the determination that the drawer has been pulled out from the image forming position. The image forming device according to claim 2, characterized in that the control unit cancels the jam error based on determining that the elapsed time since the drawer was pulled out from the image forming position is equal to or longer than a predetermined time. The image forming apparatus according to claim 2 or 3, characterized in that the control unit releases the jam error based on a change in impedance between the photoconductor and the transfer device before the drawer is pulled out from the image forming position and after the drawer is pulled out from the image forming position. The image forming device according to any one of claims 1 to 4, characterized in that the control unit determines that the drawer is placed in the image forming position when a signal is obtained from the temperature sensor after a state in which a signal is not obtained from the temperature sensor. The image forming device according to claim 5, characterized in that the control unit starts energizing the memory when the cover is closed after the drawer is placed in the image forming position. The image forming device according to any one of claims 1 to 6, characterized in that the cartridge has a container for containing developer and is detachable from the drawer. The drawer includes a drawer memory,
the drawer-side connector is electrically connected to the drawer memory;
The control unit is
8. The image forming apparatus according to claim 1, wherein when the cover is opened, power supply to the drawer memory is stopped. A main body housing;
a cover for opening and closing the opening of the main body housing;
a drawer that holds a cartridge having a semiconductor element and that can be pulled out from the image forming position of the main body housing through the opening to the outside of the main body housing;
A passive element provided in the drawer;
a drawer-side connector provided in the drawer and electrically connected to the semiconductor device and the passive device;
A control unit provided in the main body housing;
a housing-side connector provided in the main body housing and electrically connected to the control unit;
the drawer-side connector and the housing-side connector are in contact with each other when the drawer is in the image forming position and are separated from each other when the drawer is pulled out from the image forming position;
The control unit is
When the cover is opened, power supply to the semiconductor element is stopped;
determining that the drawer has been pulled out from the image forming position when a signal is no longer obtained from the passive element;
2. An image forming apparatus according to claim 1, wherein the passive element is a thermistor whose resistance value changes depending on temperature .

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