JP2017107053A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce power consumption in an image forming apparatus comprising a function unit by suppressing the number of times a power-saving mode is switched to a normal mode.SOLUTION: According to the present invention, there is provided an image forming apparatus that can operate in a normal mode and a power-saving mode with power consumption smaller than that of the normal mode. The image forming apparatus includes a CPU 201a that executes applied voltage adjustment processing after an intermediate transfer unit 221 is replaced. A control condition detection part 220 detects that the intermediate transfer unit 221 is replaced during the operation in the power-saving mode independent of the CPU 201a. After a change from the power-saving mode to the normal mode, the CPU 201a determines whether to execute the applied voltage adjustment processing according to a result of detection performed by the control condition detection part 220.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an image forming apparatus including a detachable functional unit.

  2. Description of the Related Art In recent years, power saving has been demanded for image forming apparatuses such as copiers due to increasing user awareness of the environment. Hereinafter, an image forming apparatus will be described as an example. In the image forming apparatus, a technique has been developed that automatically switches the image forming apparatus from a normal mode to a power saving mode (such as a power saving mode or a sleep mode) after a predetermined time has elapsed since the end of printing or the end of a user operation. . By switching from the normal mode to the power saving mode, power consumption during standby can be reduced. When switching to the power saving mode, conditions such as the printing conditions set at that time are stored in the storage means.

In an image forming apparatus having a functional unit that performs a specific function, such as an intermediate transfer unit, an adjustment operation that is required when returning from the power saving mode to the normal mode may be performed on the functional unit. . Hereinafter, an example of a detachable intermediate transfer unit used in the image forming apparatus as the functional unit will be described.
The intermediate transfer unit needs to be replaced periodically. In many cases, the new intermediate transfer unit after replacement and the old intermediate transfer unit after replacement have different operating characteristics with respect to voltage due to deterioration over time.

  Therefore, after the replacement of the intermediate transfer unit, a change in the control conditions of the intermediate transfer unit occurs, for example, the voltage value required for forming a desired image varies. Therefore, an adjustment operation such as adjustment of a voltage value corresponding to a change in control conditions is required. Even if the intermediate transfer unit is not replaced, the control conditions of the intermediate transfer unit change when the number of printed pages reaches a predetermined number, or when the power ON / OFF count, the temperature or humidity of the intermediate transfer unit, etc. change. There is a case. Since the control unit of the image forming apparatus is in the sleep state during the power saving mode, it cannot detect a change in the control condition of the functional unit. For this reason, in the image forming apparatus, the adjustment operation is executed every time the power saving mode returns to the normal mode.

  However, recent image forming apparatuses often stand by in a power saving mode in order to reduce power consumption. If the adjustment operation is performed for each of the functional units for each return from the power saving mode, time is consumed for that purpose, and the productivity of the image forming apparatus is lowered, resulting in a loss of convenience for the user.

  On the other hand, the image forming apparatus described in Patent Document 1 detects whether or not a detachable functional unit has been removed by a user during standby in the power saving mode. When it is detected that the detachable functional unit has been removed, the power saving mode is switched to the normal mode.

JP 2012-137606 A

In Patent Document 1, when the image forming apparatus is in the power saving mode, when the connected functional unit is attached or detached, the image forming apparatus is returned to the normal mode, and the adjustment operation is performed by performing the adjustment operation. Usability has been improved.
However, in Patent Document 1, since the image forming apparatus is switched to the normal mode every time the functional unit is removed or attached, an unnecessary return operation from the power saving mode to the normal mode may occur. As a result, an increase in power consumption and generation of operation sounds are caused.
Therefore, an object of the present invention is to reduce the power consumption of the image forming apparatus by suppressing the number of times of switching from the power saving mode to the normal mode in the image forming apparatus including the functional unit.

  In order to solve the above problems, an image forming apparatus of the present invention is an image forming apparatus controlled based on a first mode and a second mode that consumes less power than the first mode, and uses toner. An image forming means for forming an image, an intermediate transfer body to which the image formed by the image forming means is transferred, a transfer means for transferring the image transferred to the intermediate transfer body to a sheet, and the image Execution means for performing adjustment operation for controlling adjustment relating to the image transferred to the sheet in a state where the forming apparatus is controlled based on the first mode, and detection for detecting that the intermediate transfer member has been replaced And when the image forming apparatus is controlled based on the first mode after being controlled based on the second mode, the execution means is based on the detection result of the detection means. And a control means for controlling whether or not to perform the adjustment operation.

The image forming apparatus according to the present invention can acquire a detection result from a detection unit that detects, independently of the control unit, that the control condition has changed in the power saving mode after changing from the power saving mode to the normal mode. By executing the adjustment operation required when the control condition changes according to the detection result, the adjustment operation can be executed only when necessary.
Therefore, the image forming apparatus does not need to switch from the power saving mode to the normal mode in order to detect the control condition change of the functional unit, and can suppress the number of times of switching from the power saving mode to the normal mode. As a result, the power consumption of the image forming apparatus can be reduced.

FIG. 1 is a functional block diagram of an image forming apparatus. (A) is explanatory drawing of a control condition detection part, (b) is a graph showing logic values, such as a clock input line. 6 is a flowchart illustrating an attachment / detachment detection operation of an intermediate transfer unit. The flowchart showing the process performed when a power supply is turned on from the power-off state. The graph showing primary transfer high voltage output control.

  FIG. 1 is a schematic sectional view of the image forming apparatus 100. The image forming apparatus 100 can operate in a first mode (normal mode) in which an image is formed on a sheet and a second mode (power saving mode) in which power consumption per unit time is smaller than that in the first mode. When the image forming apparatus 100 is controlled based on the second mode, the rotational driving of the photosensitive drums 3y, 3m, 3c, and 3k and the driving roller 26 is stopped, and the power supply to the fixing device 5 is stopped. The Therefore, the image forming apparatus 100 is prohibited from forming an image while the image forming apparatus 100 is controlled based on the second mode. When a signal instructing execution of image formation is input while the image forming apparatus 100 is controlled based on the second mode, the mode of the image forming apparatus 100 is automatically changed from the second mode to the first mode. Changes. Note that, for example, the image forming apparatus 100 is controlled based on the first mode when the CPU 201a (FIG. 2) of the image forming apparatus 100 receives image data transferred from a PC or scanner as an external apparatus. May be.

The image forming apparatus 100 includes a cassette 4, image forming units 1y, 1m, 1c, and 1k, an intermediate transfer unit 221, a fixing device 5, and the like. The image forming unit 1y includes a photosensitive drum 3y that functions as a photosensitive member, a charger (not shown) that charges the photosensitive drum 3y, and a developing device (not shown) that develops an electrostatic latent image on the photosensitive drum 3y. . The exposure device 6 forms electrostatic latent images on the photosensitive drums 1y, 1m, 1c, and 1k. At this time, the laser beam irradiated from the exposure device 6 scans the photosensitive drums 3y, 3m, 3c, and 3k charged by the charger.
The image forming unit 1y and the exposure device 6 form a yellow toner image on the photosensitive drum 3y. The image forming unit 1m and the exposure device 6 form a magenta toner image on the photosensitive drum 3m. The image forming unit 1c and the exposure device 6 form a cyan toner image on the photosensitive drum 3c. The image forming unit 1k and the exposure device 6 form a black toner image on the photosensitive drum 3k.

  The intermediate transfer unit 221 includes an intermediate transfer belt 23 as an intermediate transfer member that is wound around rollers 25, 26, 27, 28, and 29. The intermediate transfer unit 221 also includes primary transfer rollers 2y, 2m, 2c, and 2k that press the intermediate transfer belt 23 against the photosensitive drums 3y, 3m, 3c, and 3k, and a secondary transfer roller 22. The toner images on the photosensitive drums 3y, 3m, 3c, and 3k are sequentially superimposed and transferred to the intermediate transfer belt 23. As a result, the intermediate transfer belt 23 carries a full-color toner image. The toner image on the intermediate transfer belt 23 is conveyed to the secondary transfer portion T2 and secondarily transferred to the sheet P. When the sheet P on which the toner image is transferred passes through the heating nip of the fixing device 5, the fixing device 5 fixes the toner image on the sheet P by the heat of the heater (not shown) and the pressure of the roller pairs 5a and 5b. Let The sheet on which the toner image is fixed is discharged to the tray 7 by the discharge roller 11.

  The separation roller 8 separates the sheets P drawn from the cassette 4 one by one and sends them to the registration roller 9. The registration roller 9 causes the sheet P to temporarily stand by, and allows the toner image formed on the intermediate transfer belt 23 and the sheet P to pass through the secondary transfer portion T2 at substantially the same timing. It is conveyed to the next transfer portion T2.

  The fixing device 5 presses the pressure roller 5b against the fixing roller 5a provided with a heater to form a heating nip. The toner image transferred onto the sheet P is melted by being heated and pressurized in the process of being nipped and conveyed by the heating nip. As a result, the image is fixed on the sheet P.

  The image forming units 1y, 1m, 1c, and 1k are configured substantially the same except that the color of toner used in each developing device is different from yellow, magenta, cyan, and black. Hereinafter, the image forming unit 1y will be described, and the other image forming units 1m, 1c, and 1k will be described by replacing y at the end of the code in the description of the image forming unit 1y with m, c, and k.

  The image forming unit 1y includes a replaceable unit (process cartridge) including the photosensitive drum 3y. The photosensitive drum 3y has a negatively charged photosensitive layer formed on the outer peripheral surface of an aluminum cylinder. The photosensitive drum 3y is rotated at a predetermined process speed by a driving force transmitted from a driving motor (not shown). The photosensitive drum 3y is charged to a uniform negative potential using a charger (not shown) built in the image forming unit 1y.

  The exposure device 6 has a light source that emits a laser beam based on yellow image data generated from the image data. The laser beam emitted from the light source is deflected by a rotating mirror and scans the surface of the photosensitive drum 3y charged with the laser beam. As a result, a yellow electrostatic latent image is formed on the photosensitive drum 3y. A developing device (not shown) of the image forming unit 1y develops the electrostatic latent image on the photosensitive drum 3y using yellow toner. As a result, a yellow toner image is formed on the photosensitive drum 1y.

  The intermediate transfer unit 221 is a functional unit that is disposed above the image forming units 1y, 1m, 1c, and 1k and is detachable from the image forming apparatus 100.

  The intermediate transfer belt 23 is supported around a tension roller 27, a drive roller 26, a secondary transfer stretch roller 25, and primary transfer stretch rollers 28 and 29, and is driven by the drive roller 26 to rotate in the direction of arrow R2. . The intermediate transfer belt 23 is an endless belt member whose base material is hardly expanded or contracted by a material such as polyimide, and is hung so as to reverse the rotation direction between the driving roller 26 and the secondary transfer stretching roller 25. Has been passed.

  Corresponding to the image forming units 1y, 1m, 1c, and 1k, the intermediate transfer unit 221 includes primary transfer rollers 2y, 2m, 2c, and 2k. The primary transfer roller 2 y presses the intermediate transfer belt 23 to form a primary transfer portion Ta between the photosensitive drum 3 y and the intermediate transfer belt 23. The negative toner image carried on the photosensitive drum 3y is primarily transferred onto the intermediate transfer belt 23 at the primary transfer portion Ta by applying a positive DC voltage to the primary transfer roller 2y.

  FIG. 2 shows a functional block diagram of the image forming apparatus 100. The control function unit 200 comprehensively controls various operations performed by the image forming apparatus 100. For example, the driving of each load in the image forming apparatus 100 is controlled, the information acquired by the sensor is collected, the acquired information is analyzed, and whether each functional unit is connected to a predetermined position is detected. To do.

  An emergency night power source 216 and a night power source 215 are connected to the control function unit 200. The emergency night power supply 216 outputs a large amount of power for use during image forming operation or standby. The emergency night power source 215 is a power source for efficiently performing a low-current power output in the power saving mode for minimizing the power consumption of the apparatus when the image forming operation is not performed. The control function unit 200 controls the operation of the night power supply and the emergency power supply 215 according to the mode of the image forming apparatus.

The control function unit 200 includes a CPU (Central Processing Unit) 201a for controlling the above-described operation and a ROM (Read Only Memory) 201b in which a program executed by the CPU 201a is stored. The control function unit 200 also includes a RAM (Random Access Memory) 201c. The CPU 201a executes a program stored in the ROM 201b and executes various control sequences related to image formation. The RAM 201c functions as a system work memory. The CPU 201a can rewrite the data stored in the RAM 201c. The RAM 201c holds, for example, a high voltage setting value of the high voltage control unit 205, various data described later, drive setting information regarding a detachable functional unit, and the like.
The CPU 201a executes high voltage output adjustment and determines a high voltage setting value suitable for the intermediate transfer belt 23. The high voltage control unit 205 then determines the transfer voltage supplied to the primary transfer rollers 2y, 2m, 2c, and 2k by the high voltage unit 206 and the transfer voltage supplied to the secondary transfer roller 22 based on the high voltage setting value. Control. Accordingly, even when the intermediate transfer belt 23 is replaced, the image forming apparatus 100 can suppress the occurrence of transfer failure.

  The operation unit 202 receives information such as a copy magnification and a target value of image density from the user. The operation unit 202 includes a power button of the image forming apparatus 100, a mode selection button for setting the mode of the image forming apparatus 100 (such as the first mode and the second mode), and a numeric keypad. Furthermore, the operation unit 202 includes a display (display unit) and the like, and displays the state of the image forming apparatus, for example, the number of images formed, information on whether or not an image is being formed, occurrence of a jam, and the location thereof.

  A motor, a clutch, and a solenoid are provided inside the image forming apparatus 100. In the following description, these are referred to as a motor 212. The CPU 201 a controls the motor 212 through the motor control unit 207. The image forming apparatus 100 is also provided with sensors such as a photo interrupter and a micro switch. In the following description, these sensors are referred to as sensors 214. The CPU 201a controls the sensor 214 through the sensor IF 209.

  The control condition detection unit 220 can detect that the intermediate transfer unit 221 has been replaced while the image forming apparatus 100 is controlled based on the second mode (power saving mode). The control condition detection unit 220 is provided with a storage unit that stores detection results. Further, even when the temperature of the intermediate transfer unit 221 becomes equal to or higher than the first temperature while the image forming apparatus 100 is controlled based on the second mode (power saving mode), it is detected as a change in control condition. Good. Furthermore, a case where condensation occurs on the intermediate transfer belt 23 or a case where the temperature of the intermediate transfer unit 221 is equal to or lower than the second temperature may be detected as a change in control conditions. Here, the first temperature is, for example, 50 [° C.], and the second temperature is, for example, 0 [° C.]. This is because in these cases, an adjustment operation is required to cool the intermediate transfer unit 221 and to eliminate condensation and freezing of the intermediate transfer belt 23. The adjustment operation is, for example, an operation of driving the fixing device 5 to increase the temperature inside the image forming apparatus 100 or driving a fan (not shown) to decrease the temperature inside the image forming apparatus 100. .

Hereinafter, the high pressure adjustment control in which the CPU 201a adjusts the high pressure set value when the intermediate transfer unit 221 is replaced will be described. The control condition detection unit 220 can detect that the intermediate transfer unit 221 has been replaced even when the image forming apparatus 100 is controlled based on the second mode (power saving mode). The night-time power supply 215 supplies power to the control condition detection unit 220.
On the other hand, the CPU 201a is in a dormant state in the second mode (power saving mode). During the second mode (power saving mode), the CPU 201a cannot detect that the intermediate transfer unit 221 has been replaced. Therefore, the CPU 201a acquires the detection result stored in the storage unit of the control condition detection unit 220 after returning from the second mode (power saving mode) to the first mode (normal mode). For example, the CPU 201a determines whether or not the intermediate transfer unit 221 has been replaced during the power saving mode before the image is transferred to the intermediate transfer belt 23 after the change from the second mode to the first mode.

  Further, the CPU 201a performs predetermined processing according to the detection result. For example, when the intermediate transfer unit 221 remains detached, a display prompting the user to attach the intermediate transfer unit 221 is performed through the display unit of the operation unit 202.

  In FIG. 2, the belt edge sensor 61 and the home position sensor 82 are shown as the sensor 214, but other sensors such as a density detection sensor may be provided. In addition, the CPU 201 a sends various high voltage control signals to the high voltage function unit 206 through the high voltage control unit 205 to control the high voltage function unit 206. The high-voltage functional unit 206 applies an appropriate high voltage to the charger, the transfer charger, and the developing roller in the developing device. The CPU 201a performs output adjustment as an adjustment operation so that the output value of the high-voltage functional unit 206 becomes an appropriate output value according to the state of the connected functional unit.

  For this purpose, the control device 200 adjusts the output at irregular timing such as when the power is turned off / on or when a functional unit is exchanged, or at regular timing such as when a predetermined number of prints are performed. By adjusting the output in this way, it is possible to maintain an appropriate output corresponding to an output change due to functional unit replacement or a change with time.

Note that the high-voltage control unit 205, the motor control unit 207, the control condition detection unit 220, and the like can be incorporated as hardware. These functional units such as the high-voltage control unit 205 may be realized in software by the CPU 201a reading a necessary program from the ROM 201b and forming the functional unit in the RAM 201c.
Hereinafter, in response to the detection of the intermediate transfer unit 221 being removed by the control condition detection unit 220, an applied voltage adjustment process to the intermediate transfer unit 221 is performed as a process executed when returning from the power saving mode. An example is shown.

  An explanatory diagram of the control condition detection unit 220 is shown in FIG. 3A, and logical values in the clock input line 31, the detection signal line 32, and the detection cancellation signal line 33 in FIG. 3A are shown in FIG. In FIG. 3B, the initial state before time t1 is the power saving mode and the intermediate transfer unit 221 is not removed, and the logic values of the clock input lines 31 and the like are all “L”. Yes. t1 represents a time point when the intermediate transfer unit 221 is removed in the power saving mode, and t2 represents a time point when the intermediate transfer unit 221 is connected. Further, t3 represents a point in time when the CPU 201a outputs a reset signal to the detection cancellation signal line 33 as a detection cancellation signal.

  In FIG. 3A, the control condition detection unit 220 needs to be operable even in the power saving mode in which the power consumption is smaller than that in the normal mode. Therefore, the control condition detection unit 220 is connected to the night power supply 215. Therefore, the control condition detection unit 220 operates in the normal mode as the first mode. In this embodiment, the control condition detection unit 220 includes a D-type flip-flop circuit (hereinafter simply referred to as an FF circuit) 30.

  The input D of the FF circuit 30 is connected to the ground (GND), and the low level signal “L” is always input. The clock input line 31 of the FF circuit 30 is connected to one end of the connection signal line 34 in the intermediate transfer unit 221 via the switch S. The other end of the connection signal line 34 is grounded. In addition, a voltage is applied to the clock input line 31 from a power supply at night, and one end of a capacitor C is connected to the clock input line 31. The other end of the capacitor C is grounded.

  Accordingly, when the intermediate transfer unit 221 is attached to the image forming apparatus 100, the clock input line 31 of the FF circuit 30 is grounded via the switch S and the connection signal line 34. As a result, “L” is input to the clock input of the FF circuit 30. On the other hand, when the intermediate transfer unit 221 is removed, the clock input line 31 is released from the ground state. As described above, since the voltage from the power source is applied to the clock input line 31, the capacitor C is charged, and the high level signal “H” is input to the FF circuit 30 through the clock input line 31.

  The PRESET line 35 extending from the PRESET terminal of the FF circuit 30 is connected to the collector side of the NPN transistor T1, and a voltage is applied from the power supply at night. The emitter of the NPN transistor T1 is grounded, and the base is connected to the CPU 201a through the detection cancellation signal line 33. In the normal mode, the CPU 201 a inputs a low level signal “L” to the detection cancellation signal line 33. Therefore, the NPN transistor T1 is not turned on, and the PRESET line 35 is not grounded. On the other hand, “H” is input to the PRESET line 35 since the voltage is applied from the power supply all night.

  The Q terminal of the FF circuit 30 is connected to the base of the NPN transistor T2. Here, as shown in the figure, the detection signal line 32 connected to the CPU 201a is connected to the collector side of the NPN transistor T2, and the emitter side of the NPN transistor T2 is grounded. While the intermediate transfer unit 221 is not removed and the Q terminal output is “H”, the NPN transistor T2 is in the operating direction and the detection signal line 32 is connected to the ground, and “L” is input. In the first embodiment, this state is a functional unit non-exchange state.

  In the configuration as described above, when the CPU 201a shifts to the power saving mode, the output to the detection cancellation signal line 33 is set to “H”, and the NPN transistor T1 is turned on. As a result, the PRESET terminal of the FF circuit 30 is grounded and “L” is input, and the Q terminal output becomes “H” in the initial state.

  When the image forming apparatus 100 shifts to the power saving mode, the low power state is maintained until the image forming apparatus 100 returns to the normal mode by a user operation or the like from the operation unit 202. During the power saving mode, while the intermediate transfer unit 221 is not removed and the Q terminal output is “H”, the NPN transistor T2 is in the operating direction, and the detection signal line 32 is connected to the ground (GND) to be “L”. Is entered.

Hereinafter, the operation of the FF circuit 30 when the intermediate transfer unit 221 is removed in the power saving mode will be described.
Referring to FIG. 3B, when the intermediate transfer unit 221 is removed at time t1, the clock input line 31 of the FF circuit 30 is released from the ground state. Therefore, the rising edge from “L” to “H” is input to the CLK terminal due to the voltage from the above-mentioned night-time power supply. As a result, the D terminal input is propagated by edge detection, and the Q terminal output of the FF circuit 30 changes to “L”.

  When the Q terminal output becomes “L”, the NPN transistor T2 becomes non-conductive, and the detection signal line 32 is released from the ground state. Further, since an emergency night power supply is connected to the detection signal line 32 via a resistor, “H” is output from the detection signal line 32 to the CPU 201a. When the image forming apparatus 100 returns from the power saving mode to the normal mode with the intermediate transfer unit 221 removed as described above, the input of the detection signal line 32 to the CPU 201a is “H” as shown in FIG. To change.

  When the intermediate transfer unit 221 is not removed, the input of the detection signal line 32 to the CPU 201a remains “L”. It should be noted that no control is performed from the CPU 201a in the process of detecting that the intermediate transfer unit 221 is removed in the power saving mode described above. Therefore, in this embodiment, the control condition detection unit 220 detects that the intermediate transfer unit 221 has been removed independently of the CPU 201a.

Therefore, the CPU 201a can detect whether the intermediate transfer unit 221 has been removed by determining whether the input of the detection signal line 32 is “L” or “H” when returning from the power saving mode. it can. When performing this detection, the CPU 201a does not need to return the apparatus to the normal mode in the power saving mode. As a result, the CPU 201a can determine whether or not to perform output adjustment when shifting to the normal mode based on the detection result. In the example shown in FIG. 3A, the CPU 201a cannot determine from the output of the control condition detection unit 220 whether the intermediate transfer unit 221 is currently attached.
As described above, the logical value of the clock input line 31 is “L” when the intermediate transfer unit 221 is attached, and “H” when the intermediate transfer unit 221 is removed. Therefore, for example, by branching the clock input line 31 and connecting it to the CPU 201a, the CPU 201a can determine whether or not the intermediate transfer unit 221 is currently connected.

  In this embodiment, in the power saving mode, when the intermediate transfer unit 221 is removed and the intermediate transfer unit 221 is attached again, the clock input line 31 is grounded through the connection signal line 34 again. As a result, as indicated by t2 in FIG. 3B, a falling edge from “H” to “L” occurs in the clock input line 31.

  However, in general, in the D-type flip-flop, the output change due to the falling edge at the clock input does not occur. Also in the FF circuit 30 used in this embodiment, the Q terminal is maintained at “L”, and the signal level of the detection signal line 32 input to the CPU 201a is also maintained at “H”. As a result, the CPU 201a can determine that the intermediate transfer unit 221 has been removed at least once even if the intermediate transfer unit 221 is removed and reattached during the power saving mode. Therefore, the CPU 201a can determine whether or not to execute the applied voltage adjustment process according to the detection result of the FF circuit 30.

  Once the intermediate transfer unit 221 is removed, it is preferable to adjust the output even if it is reattached during the power saving mode. Therefore, it is advantageous to be able to detect that the intermediate transfer unit 221 has been removed at least once as described above.

  Further, as indicated by t3 in FIG. 3B, the CPU 201a outputs “H” to the detection release line 33 as a reset signal, thereby bringing the NPN transistor T1 into a conductive state and the output of the Q terminal in the initial state. To “H”. As a result, the logical value of the detection signal line 32 returns to “L” in the initial state, and all the output values of the FF circuit 30 return to the initial state. Thereafter, the CPU 201a outputs “L” to the detection release line 33 and returns to the initial state.

  Note that the attachment / detachment detection method of the intermediate transfer unit 221 using the FF circuit 30 described in this embodiment is exemplary. As long as the attachment / detachment of the intermediate transfer unit 221 can be detected independently of the CPU 201a while the CPU 201a is in the power saving mode, any other method may be used as the attachment / detachment detection method.

  FIG. 4 is a flowchart showing the attachment / detachment detection operation of the intermediate transfer unit 221. Unless otherwise noted, the steps in each flowchart are executed by the CPU 201a.

  The CPU 201a detects that the image forming apparatus 100 has shifted from the sleep mode to the normal mode (S401), and detects the logic of the clock input line 31 (S402). Thereafter, the CPU 201a determines whether or not the detected logic is “H” (S403). When the logic is “H” (S403: Y), it is determined that the intermediate transfer unit 221 has been attached / detached (S404), and a transfer high-voltage output adjustment operation for adjusting the transfer high-voltage output applied to the intermediate transfer unit 221. Is executed (S405). Thereafter, the CPU 201a executes image formation (S406). On the other hand, when the logic of the detection signal line 32 is “L”, it is determined that the attachment / detachment is not performed (S403: N), and S406 is executed.

  When the image forming operation is completed in S <b> 406 and the CPU 201 a shifts to the power saving mode again, the CPU 201 a outputs “H” to the detection cancellation signal line 33. As a result, “H” is input to the PRESET terminal of the FF circuit 30 and a clear operation is performed (S407). The CPU 201a determines whether or not an instruction to end the attachment / detachment detection process of the intermediate transfer unit 221 is input from the user (S408). If the instruction is input, the CPU 201a ends the attachment / detachment detection process (S410). In other cases, the mode shifts to the sleep mode (S408), and S401 is executed again.

  By performing such an operation at the time of transition from the sleep mode to the normal mode, the image forming apparatus 100 can detect whether the intermediate transfer unit 221 has been attached or detached. By determining whether or not to perform the adjustment mode according to the detection result, the adjustment mode can be omitted when the high-voltage output adjustment is unnecessary, and the normal mode can be quickly returned to. As a result, the time required for the image forming operation is shortened, and the convenience for the user can be improved.

  In the above description, the processing when returning from the power saving mode has been described. In the power saving mode, the night-time power supply is always turned on, but when the image forming apparatus 100 is turned off, the night-time power supply may be turned off.

  FIG. 5 is a flowchart illustrating processing executed by the CPU 201a when the power of the image forming apparatus 100 is turned off and the power is turned on from the state where the night-time power is also turned off. When power is supplied by the main switch operation of the image forming apparatus 100 (S501), the CPU 201a performs high-voltage output adjustment control (S502). This is because, in this embodiment, when the power is turned off, the power supply is always turned off, so the state of the intermediate transfer unit 221 is unknown.

  When the adjustment is completed, the CPU 201a determines whether or not a print job has occurred (S503). If no print job has occurred (S503: N), the CPU 201a enters the standby state by executing S503 again. . When a print job has occurred (S503: Y), the CPU 201a executes an image forming operation (S504).

  Thereafter, the CPU 201a determines whether or not an instruction to end the attachment / detachment detection process of the intermediate transfer unit 221 has been input from the user (S505). If the instruction has been input, the CPU 201a ends the attachment / detachment detection process (S506). In other cases, S503 is executed again.

  6A and 6B are graphs for explaining the primary transfer high-voltage output control. When the intermediate transfer belt 23 is replaced, the image forming apparatus detects the first current and the second current for the different first voltage and second voltage with respect to the intermediate transfer body, respectively, in order to perform output control. . The voltage value and application time at this time are shown in FIG. From the result, the relationship between the voltage and the current is linearly approximated to create an IV proportional line, and a voltage Vtrgt for inputting a desired current to the intermediate transfer belt 23 is obtained. The obtained calibration curve is shown in FIG. In this embodiment, after obtaining the IV proportional line, the input current Itrgt = 15 [μA] of the intermediate transfer belt 23 is set as a desired current, and the input voltage corresponding to this value is obtained.

  6A, in order to obtain the first current, the image forming apparatus 100 applies a primary transfer high voltage Vtr1 = 1000 [V] as the first voltage. At this time, in order to obtain an average current for one rotation of the primary transfer roller 2, first, after waiting for 100 [ms] as a stabilization time, voltage application is performed for 208 [ms] that is an application time for one rotation of the roller. Thereafter, the CPU 201a detects an output current via the AD converter 208 in order to perform current detection. Specifically, 26 samplings of output values were acquired at 8 [ms] intervals. When the 26 sampling values were averaged, the average current Icount1 was 10 [μA].

Next, the primary transfer high voltage Vtr2 = 2000 [V] was applied as the second voltage, and the average current Icount2 was detected in the same manner as when the first voltage was applied under other conditions. The value of Icount2 at this time was 20 [μA]. From these detection results, an IV proportional line can be obtained from the values of Icount1 and Icount2 when the first voltage Vtr1 and the second voltage Vtr2 are applied. This IV proportional line is expressed as follows.
Vtrgt = {(Vtr2-Vtr1) / (Icount2-Icount1)} * Itrgt
Thereby, the resistance value represented by (Vtr2-Vtr1) / (Icount2-Icount1) is detected.

In this embodiment, since the value of (Vtr2-Vtr1) / (Icount2-Icount1) obtained as a detection result is 100, Vtrgt when Itrgt = 15 [μA] is obtained as 1500 V. it can. Further, the control time required for performing the primary transfer high-voltage output control described above in this embodiment is 616 [ms]. That is, when it is determined that the functional unit has not been changed by the functional unit attachment / detachment detection, the high-voltage output control can be omitted, and 616 [ms] is shortened in return from the sleep mode compared to the conventional control. It is possible.
In this embodiment, the high voltage output control has been described as an example of the control that can be omitted by detecting the functional unit attachment / detachment. However, this embodiment can also be applied to other controls related to a detachable functional unit.

  The embodiment described above is for specifically explaining the present invention, and does not limit the scope of the present invention. Various forms within the scope of the present invention are also included in the present invention.

Claims (6)

An image forming apparatus controlled based on a first mode and a second mode that consumes less power than the first mode,
Image forming means for forming an image using toner;
An intermediate transfer body to which the image formed by the image forming means is transferred;
Transfer means for transferring the image transferred to the intermediate transfer member to a sheet;
Execution means for executing an adjustment operation for controlling adjustment related to the image transferred to the sheet in a state where the image forming apparatus is controlled based on the first mode;
Detecting means for detecting that the intermediate transfer member has been replaced;
When the image forming apparatus is controlled based on the first mode after being controlled based on the second mode, whether or not the execution unit performs the adjustment operation based on a detection result of the detection unit. An image forming apparatus comprising: control means for controlling   The control unit controls whether or not the execution unit performs the adjustment operation based on a detection result of the detection unit before the image forming unit forms the image. Item 2. The image forming apparatus according to Item 1. The detection unit includes a storage unit that stores the detection result when the intermediate transfer body is replaced in a state where the image forming apparatus is controlled based on the second mode.
The image forming apparatus according to claim 1, wherein the control unit controls whether or not to cause the execution unit to execute the adjustment operation based on the detection result stored in the storage unit. It further has a detecting means for detecting the resistance value of the intermediate transfer member,
In the adjusting operation, the transfer unit applies a voltage to the intermediate transfer member, the detection unit detects the resistance value of the intermediate transfer member, and the transfer unit detects the image based on the detection result of the detection unit. The image forming apparatus according to claim 1, wherein the image forming apparatus is an operation of adjusting a transfer voltage for transferring the image to the sheet. The detection means has a flip-flop circuit,
5. The image forming apparatus according to claim 1, wherein the detection unit detects that the intermediate transfer member has been replaced from an output value of the flip-flop circuit. 6.   2. The display device according to claim 1, further comprising display means for displaying a display for prompting a user to attach the intermediate transfer body when the detection means detects that the intermediate transfer body remains detached. The image forming apparatus according to claim 5.

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