JP5707996B2 - Image forming apparatus and control method - Google Patents

Description

  The present invention relates to an image forming apparatus (a copying machine, a printer, a multifunction peripheral, etc.) that shifts to a power saving operation and returns to a normal operation in response to external light in an installation environment, and a method for controlling the image forming apparatus.

In recent years, with increasing awareness of environmental problems, image forming apparatuses such as copiers, printers, and multifunction machines are required to realize power saving with a high goal.
The power saving in the image forming apparatus recognizes that there is no print job to be processed, that is, the device is in a so-called idle state, and when this state is recognized, an operation unit (for example, command input that requires constant power supply) is recognized. It is well known to use power saving control in an operation mode called a standby mode or a sleep mode in which power supply is basically stopped, while maintaining power supply to the operation unit or the like) .

Further, as a method other than the above, there is no light generated outside the machine, light from daylight (hereinafter referred to as “external light”), that is, there is no light illuminating the place where the image forming apparatus is installed, and the user Assuming the situation of moving away from the installation location, there is also a technology that uses the method of shifting to the power saving mode on the condition that such a situation is unlikely to use the image forming apparatus. It has been.
As a conventional example employing the latter method, Patent Document 1 (Japanese Patent Laid-Open No. 2006-184346) can be cited.

  In Patent Document 1, for the purpose of suppressing power consumption when forgetting to turn off the power, the power saving operation is performed on the premise of detecting a decrease in illuminance in the installation environment. It is described that a function that can be changed by the user is mounted on the operation panel. The function that can be changed by the user is a function realized by including a reference illuminance setting unit that sets a reference illuminance (device-specific threshold) and a time setting unit that sets activation of power saving control. By activating power saving control when the output of the sensor that detects the illuminance in the installation environment falls below the reference illuminance set by the reference illuminance setting unit and the state continues for the time set by the time setting unit It is possible to perform an appropriate operation according to changes in the installation environment and the equipment itself.

However, in the conventional image forming apparatus as described above that can deal with sensitivity variations of the illuminance sensor and deterioration with time, and can set the reference illuminance to properly maintain the power saving control operation without causing malfunction, the operation unit Therefore, it is necessary to set the reference illuminance (threshold value), which causes a problem that it takes time and effort for the user.
The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to appropriately maintain the power saving control operation without requiring the user to perform a setting operation. is there.

The present invention provides an image forming unit that forms an image on an image carrier based on image data in accordance with a command by an input operation, a light receiving unit that can receive external light and outputs a detection value corresponding to the amount of received light The power supply to each operation unit that requires power can be supplied / stopped, and the threshold value process using a preset first reference value is performed on the detection value of the light receiving unit, and the first reference value is set. An image forming apparatus having a power saving control means for performing control to shift from a power supply state at the time of image formation to a power supply state at the time of power saving when the light source is lower, and a lighting controllable light source that emits reference light A light-emitting unit provided so that the light from the light source can be received by the light-receiving unit, the light-receiving unit, by the external light receiving signal obtained when the light source included in the light-emitting unit is not turned on Obtained when the light source of the light emitter is turned on. The reference light received signal obtained by adding the reference light to the external light is corrected, and the reference light received signal obtained by the correction is output to the power saving control unit. The power saving control unit is configured to receive the reference light received by the light receiving unit. A first reference value used for the threshold processing is set based on a signal.
The present invention provides an image forming unit that forms an image on an image carrier based on image data in accordance with a command by an input operation, a light receiving unit that can receive external light and outputs a detection value corresponding to the amount of received light, a reference A light source capable of controlling lighting to emit light, a light emitting unit provided so that the light from the light source can be received by the light receiving unit, and a preset value for a detection value of the light receiving unit A control method in an image forming apparatus that performs threshold value processing based on one reference value and performs control to shift from a power supply state at the time of image formation to a power supply state at the time of power saving when the value falls below a first reference value. A light receiving signal obtained by adding reference light to external light obtained when the light source of the light emitting unit is turned on is corrected by an external light receiving signal obtained when the light source of the light emitting unit is not turned on. Obtain and obtain the light reception signal Based on that reference light reception signal, and sets the first reference value used in the threshold process in the control to shift from the power supply state of the image formation to the power supply state of the power saving.

  According to the present invention, it is possible to perform a setting operation for the user by detecting the sensitivity variation and deterioration with time of the light receiving unit (illuminance sensor) provided for detecting external light quantitatively by the device itself and correcting the reference illuminance. Thus, the power saving control operation can be appropriately maintained without taking the time and effort.

1 is a diagram illustrating an outline of a configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a diagram illustrating a configuration example of an illuminance sensor and a light emitting element mounted on the image forming apparatus illustrated in FIG. 1 and detection states of external light and reference light. FIG. 6 is a diagram illustrating another configuration example of an illuminance sensor and a light emitting element mounted on the image forming apparatus illustrated in FIG. 1 and a detection state of external light and reference light. 1 is a block diagram illustrating a configuration of a system that controls a power saving operation of an image forming apparatus according to an embodiment of the present invention. FIG. It is a figure which shows the control flow of the power saving control (at the time of transfer) which concerns on embodiment of this invention. It is a figure which shows the setting processing flow of the reference | standard illumination value (threshold value) used by power saving control (FIG. 5, FIG. 7). It is a figure which shows the control flow of the power saving control (at the time of a return) which concerns on embodiment of this invention.

Hereinafter, embodiments of an image forming apparatus according to the present invention will be described.
An image forming apparatus according to the present invention (hereinafter also simply referred to as “apparatus”) includes a light receiving unit that detects whether natural light or artificial light (hereinafter referred to as “external light”) that illuminates the installation location of the apparatus is present. If there is no external light detected by the light receiving unit, the possibility that the device will be used is low, and conversely, if there is external light, the possibility of use is high, Based on the detection result, as power saving control operation, transition control and power saving from the power supply state during image formation (hereinafter referred to as “normal mode”) to the power supply state during power saving (hereinafter referred to as “power saving mode”) are performed. Return control from the power mode to the normal mode is performed.
In this embodiment, the detection of the presence or absence of the external light in the light receiving unit is performed as a threshold process for the detection value of the external light by the illuminance sensor that detects the amount of incident light. This threshold value process uses a predetermined illuminance reference value as a threshold value as the transition / return condition, and obtains a determination result as to whether or not the detected amount of external light satisfies the transition / return condition. Therefore, the power saving control is executed according to the obtained determination result.

As described above, when executing the power saving control, it is necessary to always operate the illuminance sensor. For this reason, the illuminance sensor is deteriorated due to a change with time, and the detection value fluctuates with respect to a certain amount of light, and this fluctuation causes a malfunction.
Therefore, in the present embodiment, by changing the threshold value (the illuminance reference value that determines the transition / recovery condition) in accordance with a decrease in output due to deterioration of the illuminance sensor that can detect the amount of external light, the above-described time-lapse Without being affected by the change, it is possible to appropriately determine the transition / return condition, and to prevent malfunction in power saving control.

Compensation for deterioration of the illuminance sensor described above can be implemented by the method described below.
That is, by irradiating the illuminance sensor with a certain amount of reference light and obtaining a detection value corresponding to the amount of received light, the degree of deterioration of the illuminance sensor can be known, and based on the degree of deterioration thus obtained, a predetermined value is obtained. The threshold value (the illuminance reference value that defines the transition / return condition) set to determine these conditions is adjusted so as to maintain the transition / return condition.
Specifically, the illuminance sensor is provided with a light emitting unit that irradiates a predetermined amount of reference light, and at the time of adjustment, the light emitting unit is driven, the reference light is received by the illuminance sensor, and the reference value is adjusted. In addition to the reference light from the light emitting unit, external light is incident on the illuminance sensor, so that a process for obtaining the detection value of the reference light is required by correcting the detection value to which the external light has been added.
The procedure for reflecting the reference light emitting section and the reference light detection result in the power saving control operation will be described in detail later.

In order to compensate for deterioration of the illuminance sensor in power-saving control that allows external light to be received by the illuminance sensor at all times and shifts and returns by threshold processing for the detected value according to the amount of received light, depending on the detected value of the reference light In the following description of the present embodiment, the method of changing the threshold will be described as transition / return control between the normal mode and the power saving mode. However, the so-called standby mode, a transition from the power-saving mode that stops power supply to the power-saving operating mode, except for the operating unit that requires constant power supply and some operating units that take time to return to the normal mode, is further introduced. The present invention can also be applied to the return control from the deep power saving mode to the standby mode.
In the following embodiments, electrophotographic image forming apparatuses (copiers, printers, multifunction devices, etc.) are used as examples. Note that power saving control is performed in the same manner, and image formation that effectively saves power is performed. Any apparatus other than electrophotography may be used as long as it is an apparatus.

  Hereinafter, power saving control in which external light is always received by an illuminance sensor and transition / return is performed by threshold processing for a detection value corresponding to the amount of received light will be described with reference to the accompanying drawings. Details of this power saving control Prior to this description, an outline of the image forming apparatus of the present embodiment will be described first.

[Outline of image forming apparatus]
FIG. 1 is a diagram illustrating an outline of a configuration of an image forming apparatus according to the present embodiment.
Here, with reference to FIG. 1, the configuration of the operation unit related to the image forming apparatus and the outline of the operation will be described. In the figure, a tandem type color image forming apparatus is illustrated, but another type or a monochrome machine may be used.
The configuration of an illuminance sensor or the like that can detect external light directly related to the power saving operation and the configuration of the control system of the image forming apparatus according to this embodiment will be described in detail later.

As shown in FIG. 1, the image forming apparatus 1 has a configuration in which AIO (All In One) cartridges (image forming units) having the number of color components are arranged along an intermediate transfer belt 12. The AIO cartridge is a module in which the electrophotographic process unit is integrated so that it can be handled as a replacement part.
The intermediate transfer belt 12 is an endless belt that rotates counterclockwise (indicated by an arrow in FIG. 1), and in order of each color component color (black, cyan, magenta, yellow) from the upstream side in the rotation direction. The AIO cartridges 2A, 2B, 2C, and 2D are arranged to form a so-called tandem type configuration. Each AIO cartridge has the same internal configuration except that the color of the toner image to be formed is different.
The AIO cartridge 2A includes a photoconductor 5A having a drum outer periphery as a photosensitive surface, a charger 6A disposed around the photoconductor 5A, an exposure device 7, a developing device 8A, a cleaning blade 9A, and the like.
The exposure unit 7 is configured to irradiate laser beams 10A, 10B, 10C, and 10D that are exposure lights corresponding to the color component colors formed by the AIO cartridges 2A, 2B, 2C, and 2D.

Further, as constituent elements related to transfer paper (hereinafter simply referred to as “paper”) 15, a paper feed tray 14 for stacking paper 15, a paper feed roller 16 for registering paper 15, a registration roller 17, and paper discharge A roller 19, a double-sided roller 20, a secondary transfer roller 13 for transferring an image formed on the intermediate transfer belt 12 to the paper 15, and a fixing device 18 for fixing the toner to the paper 15 to which the toner has been transferred. A paper discharge sensor 21 that detects that the paper 15 has passed in the vicinity of the paper discharge roller 19 is provided. The fixing device 18 obtains a high temperature necessary for fixing by a heater (not shown) driven by a power source. By making this heater an object of control during power saving, the power saving effect can be enhanced.
Furthermore, an adjustment image (pattern) such as density formed on the intermediate transfer belt 12 and a waste toner box 22 for collecting toner remaining without being transferred onto the paper 15 are disposed.

Next, a general operation in the image forming apparatus 1 configured as described above will be described.
At the time of image formation, the outer peripheral surface of the photoconductor 5A is uniformly charged by the charger 6A in the dark, and then exposed by the laser beam 10A from the exposure device 7 to form an electrostatic latent image. The developing unit 8A forms a toner image on the photoreceptor 5A through a process of making the electrostatic latent image visible with toner. The toner image on the photoconductor 5A is transferred onto the transfer belt 12 by the function of the primary transfer roller 11A at a position where the photoconductor 5A and the intermediate transfer belt 12 are in contact (primary transfer position). By this transfer, a toner image is carried on the intermediate transfer belt 12. After the toner image has been transferred, the photoreceptor 5A waits for the next image formation after the unnecessary toner remaining on the outer peripheral surface is wiped off by the cleaning blade 9A.

As described above, the intermediate transfer belt 12 that has received the transfer of the toner image formed by the AIO cartridge 2A is conveyed to the next AIO cartridge 2B. In the AIO cartridge 2B, the image formed by this cartridge is transferred to be superimposed on the image on the intermediate transfer belt 12 by the same process as the image forming process in the AIO cartridge 2A. The intermediate transfer belt 12 is further conveyed to the next AIO cartridges 2C and 2D, and is transferred onto the intermediate transfer belt 12 while being superimposed by the same operation. In this way, the full-color superimposed image is carried on the intermediate transfer belt 12. The intermediate transfer belt 12 carrying the image formed in full color is conveyed to the position of the secondary transfer roller 13.
When printing is requested, the paper 15 is sent out from the paper feed tray 14 accommodated, waits at the position of the registration roller 17, and then the toner image conveyed by the intermediate transfer belt 12 and the position of the paper 15 overlap each other. It is sent out by a roller 17.
The fed paper 15 is transferred by the secondary transfer roller 13 to the toner image on the intermediate transfer belt 12 onto the paper 15, and then the toner image is fixed by heat and pressure by the fixing device 18. Are discharged outside the image forming apparatus 1.

[Illuminance sensor]
The image forming apparatus 1 according to the present embodiment performs power saving control that shifts and returns by detecting the presence or absence of external light. For this reason, an illuminance sensor is mounted as an external light receiving unit. In the present embodiment, as described above, the external light is detected for the purpose of determining the control condition of the power saving control. Therefore, the illuminance sensor emits natural light or artificial light that illuminates the installation location of the device at a position suitable for the purpose. It is provided so that the amount of light can be detected, and a signal corresponding to the amount of received light is output.
In the example shown in FIG. 1, for example, a small window 24 that collects external light generated by the light source of the lighting fixture 40 that illuminates the periphery of the device is provided on the upper surface of the exterior cover 29 of the device. It is mounted on the device so as to receive external light that enters through the window 24.
The illuminance sensor 23 is for detecting external light, but in this embodiment, as described above, it is also used as means for detecting reference light.

FIG. 2 is a diagram illustrating a configuration example of an illuminance sensor and a light emitting element mounted on the image forming apparatus illustrated in FIG. This figure is also a diagram for explaining the light detection state of the illuminance sensor 23. In addition to functioning as a sensor for detecting external light, the illuminance sensor 23 also functions as a sensor for detecting reference light emitted by a light emitting element 25 described later. Represents. That is, in the figure, the illuminance sensor 23 receives external light that is incident through the small window 24 and reference light emitted from the light emitting element 25.
Here, the light emitting element 25 is capable of lighting control, and is required to emit a certain amount of light as reference light, and an LED (light emitting diode) is suitable as a light emitting element that satisfies this condition.

Further, it is desirable that the light emitting element 25 is used as a reference light under the condition that power consumption can be reduced as much as possible and the temporal change of the light emission amount can be suppressed. In this embodiment, as shown in the configuration example of FIG. The light emitting element 25 is provided to face the illuminance sensor 23 so that the light emitted from the light emitting element 25 can be directly received at a close position.
By adopting this arrangement, even the low power light emitted by the small driving power can be detected by the illuminance sensor 23 without waste. Further, by controlling so that the light emitting element 25 is turned on only when necessary, it is possible to save power and suppress deterioration of the light emitting element 25 itself, and as a result, the light quantity can be stabilized.

FIG. 3 is a diagram illustrating another configuration example of the illuminance sensor and the light emitting element mounted on the image forming apparatus illustrated in FIG. 1. This figure is also a diagram for explaining the light detection state of the illuminance sensor 23. In addition to functioning as a sensor for detecting external light, it also functions as a sensor for detecting reference light emitted from the light emitting element 25, as in FIG. FIG.
The illuminance sensor 23 is preferably an LED capable of controlling lighting as the light emitting element 25 that receives the reference light emitted from the light emitting element 25 in addition to the external light entering through the small window 24, and emits the reference light. In addition, by controlling so that the light emitting element 25 is lit only when necessary, it is possible to save power, suppress deterioration of the light emitting element 25 itself, and stabilize the light amount as a result. This is the same as FIG.

However, in the example of FIG. 3, as shown in FIG. 3, the light emitting element 25 is arranged side by side with the illuminance sensor 23, and the light emitted from the light emitting element 25 serves as a white reference as a reference reflecting portion provided inside the exterior cover 29. After hitting the plate 27, it is arranged so as to enter the illuminance sensor 23.
The above-described reference reflection portion can use the inner side surface of the exterior cover 29 as long as the inner side surface has reflection characteristics that meet the conditions for using the reflected light as reference light. If the surface is not a surface, as shown in the example of FIG. 3, a white reference plate 27 having a reflection characteristic suitable for the conditions for use as the reference light is provided, and the reflected light incident on the illuminance sensor 23 is stabilized. , Enabling use as a reference light.
In the reflected light type shown in the example of FIG. 3, the light emitting element 25 is arranged side by side with the illuminance sensor 23, so that the arrangement of the illuminance sensor 23 with respect to the exterior cover is closer to that of the direct light type shown in the example of FIG. 2. Since it can be arranged (“L” shown in FIG. 3 is minimized), the incident angle of the external light collected from the small window 24 can be widened. As a result, the external light detection accuracy can be increased. Furthermore, this arrangement also works effectively to reduce the overall dimensions of the device.

[Control system configuration]
A configuration of a system for controlling the power saving operation in the image forming apparatus 1 (FIG. 1) will be described.
FIG. 4 is a block diagram showing the configuration of a system that controls the power saving operation of the present embodiment. The control system shown in the figure is configured under a main controller that controls the entire image forming apparatus. However, for convenience of explanation, only the elements related to the power saving operation are shown, and the other elements are omitted. ing.

4, the system for controlling the power saving operation includes a control unit 30, a memory 32, a power supply unit 34 and a light emitting element 25 (see FIGS. 2 and 3), and an illuminance sensor 23 (see FIG. 2) under the control of the control unit 30. 1 to 3) and an electrical component 36.
The power supply means 34 performs power supply (indicated by a broken line in FIG. 4) to each element constituting the control system and stops in response to a command from the control means 30.
The memory 32 is under the control of the control means 30, and in this embodiment is used for storing a reference illuminance value (described in detail later in [Power Saving Control]) that defines the transition / return conditions in the power saving control. . The memory 32 may be a memory built in the control means 30.
The flow of data such as a control signal in the power saving control performed by the control means 30 is indicated by a solid line in FIG. The power saving control operation will be described in detail later in [Power saving control].
The electrical component 36 includes various electric devices such as various motors necessary for the operation of the image forming unit and the heater of the fixing unit 18.

By the way, a main controller of an image forming apparatus constituting a system for controlling power saving operation is not shown, but a CPU (Central Processing Unit) for operating software (program), a ROM (Read Only Memory) for storing a program, and a program It can be implemented by a computer that includes hardware such as RAM (Random Access Memory) used as a work memory when operating the computer.
In the ROM of the main controller implemented by a computer, a program for executing an operation shown in the control flow of FIGS. 5 to 7 described later as an operation related to the power saving control of the present embodiment is recorded. The CPU implements this control operation. The medium for recording the program is not limited to the above-mentioned ROM, and various storage media including disk types such as HDD (hard disk), CD-ROM, and MO (Magneto Optical Disk) can be used.

[Power saving control]
In the present embodiment, the control system (FIG. 4) performs a power saving operation, a transition control from a normal mode in which power is supplied during image formation to a power saving mode in which power is supplied during power saving, and power saving. Performs return control from mode to normal mode.
The transition condition and the return condition in this power saving control are determined by the presence of predetermined external light that can be estimated whether the equipment is likely to be used or not. That is, during the normal mode, when the illuminance of the detected external light becomes smaller than a predetermined value preset as a threshold value (“reference illuminance value” in the control flow of FIG. 5 described later), the device may be used. Is shifted to the energy saving mode from the normal mode, and the illuminance of the external light detected during the energy saving mode is a predetermined value set as a threshold value (the “reference illuminance value” in the control flow of FIG. 7 described later). ), It is considered that the possibility of using the device has increased, and the mode returns from the energy saving mode to the normal mode.
In this power saving control operation, the amount of received light (illuminance) detected by the illuminance sensor 23 described in [Illuminance sensor] is used as the detection value of the external light.
Hereinafter, each power saving control operation performed according to the above-described transition condition and return condition will be described based on the control flow.

“Transition control to power saving mode”
FIG. 5 is a diagram showing a control flow of the power saving operation (at the time of transition) according to this embodiment.
The control unit 30 activates this control flow when a status that can immediately start an image forming operation in response to a print request.
When this control flow is started, first, an illuminance detection value corresponding to the amount of received light output by the illuminance sensor 23 that receives external light is acquired (step S101). Note that the illuminance sensor 23 is always detecting, and the LED as the light emitting element 25 emits light only for a predetermined period at the time of initialization, as will be described later. Illuminance by only.

Next, threshold processing is performed on the acquired detection value of the external light using a reference illuminance value determined as a condition for shifting to the power saving mode (step S102). This threshold value process determines a transition condition for performing control to shift from the normal mode to the energy saving mode when the detected value of the external light falls below the reference illuminance value.
Here, when the detection value of the external light does not fall below the reference illuminance value (step S102-NO), the transition condition is not satisfied, so the process returns to step S101 for acquiring the detection value of the external light, and the determination of the transition condition is performed again. Do.
On the other hand, when the detected value of the external light falls below the reference illuminance value (step S102-YES), the elapsed time from this point is started and whether or not this elapsed time has reached time t is confirmed (step S102). S103). This check is performed to prevent malfunction when the external light detection value below the reference illuminance value is an abnormal value due to an accidental factor. Confirm that the state below the reference illuminance value continues. The elapsed time t is set to an appropriate time that meets the above-mentioned purpose.

Therefore, if the elapsed time t has not been reached as a result of the confirmation in step S103 (step S103-NO), it is immediately assumed that the detected value of the external light at this time exceeds the reference illuminance value, that is, an abnormal value. It is confirmed by threshold processing whether or not it is acceptable (step S104).
As a result of the confirmation, if the reference illuminance value is exceeded (YES in step S104), the current process including resetting the elapsed time t is reset, and the process returns to step S101 for acquiring the detected value of the external light. Make a decision. If the result of the confirmation in step S104 does not exceed the reference illuminance value (step S104-NO), the process returns to step S103 for confirming the elapsed time t.
On the other hand, when it is confirmed in step S103 that the detected value of the external light is lower than the reference illuminance value for the elapsed time t (step S103-YES), the normal mode is shifted to the energy saving mode. Then, the power supply means 34 is instructed to execute power saving control (step S105).
Thereafter, this control flow is terminated.

“Setting the standard illuminance value”
As described in the above “control to shift to power saving mode”, in the present embodiment, determination of establishment of the condition for shifting to the power saving mode is performed by threshold processing based on a reference illuminance value with respect to a detected value of external light by the illuminance sensor 23. To do. Also, in “return control to normal mode” described later, the establishment of the return condition to normal mode is determined by the same threshold processing.
However, as described above, since the illuminance sensor 23 is always in an operating state and deterioration is unavoidable, means for compensating for deterioration of the illuminance sensor 23 is provided in the present embodiment.
This compensation means irradiates the illuminance sensor 23 with a fixed amount of reference light and obtains a detection value corresponding to the amount of received light, thereby knowing the degree of deterioration of the illuminance sensor, and based on the degree of deterioration, the threshold value (transition / return) Adjust the illuminance reference value that defines the conditions. By performing this adjustment, it is possible to determine whether an appropriate transition / return condition is satisfied. In addition, the connection structure between the light emitting element 25 (LED) that emits the reference light and the illuminance sensor 23 is as described in [Illuminance sensor] with reference to FIGS.

Here, a reference illuminance value setting process performed as a procedure for detecting the reference light by the illuminance sensor 23 and reflecting the obtained detection result in the power saving control operation will be described.
FIG. 6 is a diagram showing a processing flow for setting a reference illuminance value (threshold value) used in power saving control (FIGS. 5 and 7).
This processing flow is performed in order to compensate for a characteristic change that does not change rapidly in a short time, that is, a change with time (deterioration) of the illuminance sensor 23, and thus is executed at the time of initialization when the device is turned on. Is appropriate. However, depending on the usage situation and installation environment, there may be cases where the method performed at power-on is not appropriate. In this case, for example, a method that is executed at predetermined time intervals may be employed.

According to the processing flow of FIG. 6, when the device is turned on, the control unit 30 starts a reference illuminance value (threshold value) setting process as part of initialization (step S201).
When this setting process is started, first, an illuminance detection value corresponding to the amount of external light received by the illuminance sensor 23 is acquired, and the acquired illuminance detection value of external light is stored in a memory for use in subsequent step S206. (Step S202).
Next, the light emitting element 25 (LED) that emits the reference light is turned on (step S203).
Thereafter, an illuminance detection value corresponding to the input light amount received by the illuminance sensor 23 and the reference light emitted by the LED added to the external light is acquired, and peak detection is performed on the acquired illuminance detection value (step S204).
After obtaining the illuminance detection value in step S204, the light emitting element 25 (LED) that has emitted the reference light immediately is turned off (step S205).

  Next, since the external light is added to the reference light emitted by the LED in the illuminance detection value that has been subjected to peak detection in step S204, a process for calculating a required reference light (LED) component is performed (step S206). . In other words, the detected illuminance value detected in step S204 is corrected by the detected illuminance value of the external light held in the memory in step S204 to obtain the detected illuminance value of the reference light to be obtained.

Next, based on the detected illuminance value of the reference light calculated in step S206, the reference illuminance value used in the power saving control (FIGS. 5 and 7) is determined, and the determined reference illuminance value is set to the power saving control (FIG. 5, FIG. 5). In order to use it as a threshold value in FIG. 7), it is set as a control condition by storing it in a memory for storing control data (step S207). At this time, the method for determining the reference illuminance value as a threshold based on the detected illuminance value of the reference light is a fixed coefficient (for example, 1/2) obtained as an empirical value to the obtained illuminance detected value of the reference light. ) Can be used. Further, the reference illuminance value (threshold) used when shifting to the power saving mode and the reference illuminance value (threshold) used when returning to the normal mode are not necessarily the same.
After setting in step S207, the process according to this flow is terminated.

“Return control to normal mode”
FIG. 7 is a diagram showing a control flow of the power saving operation (at the time of return) according to this embodiment.
The control means 30 activates this control flow when the device enters the power saving mode status by the control described in the above-mentioned “control to shift to the power saving mode”.
When this control flow is started, first, an illuminance detection value corresponding to the amount of received light output by the illuminance sensor 23 that receives external light is acquired (step S301). The illuminance sensor 23 is always detecting, and the LED as the light emitting element 25 emits light only for a predetermined period at the time of initialization. Therefore, the amount of light received at this time is the illuminance due to only external light. .

Next, threshold processing is performed on the acquired detection value of the external light using a reference illuminance value determined as a condition for returning to the normal mode (step S302). This threshold value process determines a return condition for performing control to return from the power saving mode to the normal mode when the detected value of the external light exceeds the reference illuminance value.
Here, when the detected value of the external light does not exceed the reference illuminance value (step S302-NO), the return condition is not satisfied. Therefore, the process returns to step S301 for acquiring the detected value of the external light, and the return condition is determined again. Do.
On the other hand, when the detected value of the external light exceeds the reference illuminance value (YES in step S302), the elapsed time from this time is started and whether or not this elapsed time has reached time t is confirmed (step S302). S303). This check is performed to prevent malfunction when the detected value of external light exceeding the reference illuminance value is an abnormal value due to an accidental factor. In the above, it is confirmed that the state exceeding the reference illuminance value continues. The elapsed time t is set to an appropriate time that meets the above-mentioned purpose.

Therefore, as a result of the confirmation in step S303, if the elapsed time t has not been reached (step S303-NO), it is immediately assumed that the detected value of the external light at this time is below the reference illuminance value, that is, an abnormal value. It is confirmed by threshold processing whether or not it is acceptable (step S304).
If the result of this confirmation is below the reference illuminance value (YES in step S304), the current process including resetting the elapsed time t is reset, and the process returns to step S301 for acquiring the detected value of external light, Make a decision. If the result of the confirmation in step S304 is not less than the reference illuminance value (NO in step S304), the process returns to step S303 in which the elapsed time t is confirmed.
On the other hand, when it is confirmed in step S303 that the detected external light value has exceeded the reference illuminance value for the elapsed time t (step S303-YES), the power saving mode is returned to the normal mode. Then, the power supply means 34 is instructed to execute normal power control (step S305).
Thereafter, this control flow is terminated.

As described above, according to the present embodiment, in the power saving control, the sensitivity variation and deterioration with time of the illuminance sensor 23 that detects the external light provided for determining whether or not the condition for shifting to the power saving mode is satisfied. The reference light emitted from the light emitting element 25 (LED) is received by the sensor, and is quantitatively detected by the device itself, and is set to determine whether the transition / recovery condition is satisfied based on the received light signal of the reference light. By adjusting the threshold value, that is, by correcting the reference illuminance value, the deterioration of the illuminance sensor 23 can be compensated and the operation in the power saving control can be properly maintained.
In addition, since the device itself automatically adjusts the reference illuminance value, the user is required to perform a setting operation necessary for adjusting the nonconformity of the control condition caused by deterioration of the illuminance sensor 23 or the like. It is possible to eliminate the need for the user to improve the usability.

  1. Image forming apparatus, 2A, 2B, 2C, 2D, Image forming unit (AIO cartridge), 5A, 5B, 5C, 5D, Photoconductor, 7 ... Exposure unit, 12 ... Intermediate transfer belt, 15 ..Paper, 17 ..Registration roller, 23 .. Illuminance sensor, 25 ..Light emitting element, 27 ..White reference plate, 29 ..Exterior cover, 30 ..Control means, 32. Supply means, 36 ... electrical parts, 40 ... lighting equipment.

JP 2006-184346 A

Claims (6)

An image forming unit that forms an image on an image carrier based on image data in accordance with an instruction by an input operation;
A light receiving unit capable of receiving external light and outputting a detection value corresponding to the amount of received light;
Power supply / stop control can be performed for each operation unit that requires power, and threshold processing is performed on the detection value of the light receiving unit using a preset first reference value, which is below the first reference value. An image forming apparatus having power saving control means for performing control to shift from a power supply state at the time of image formation to a power supply state at the time of power saving,
A light source that can be controlled to emit light that emits reference light, and includes a light emitting unit that is provided so that light from the light source can be received by the light receiving unit,
The light-receiving unit corrects a light-receiving signal obtained by adding reference light to external light obtained when the light source included in the light-emitting unit is turned on by an external light-receiving signal obtained when the light source included in the light-emitting unit is not turned on. , Outputting a reference light receiving signal obtained by this correction to the power saving control means,
The image forming apparatus according to claim 1, wherein the power saving control unit sets a first reference value used for the threshold processing based on a reference light reception signal output from the light receiving unit. The image forming apparatus according to claim 1,
The power saving control unit performs a threshold process based on a preset second reference value for the detection value of the light receiving unit, and when the value exceeds the second reference value, image formation is performed from a power supply state during power saving. And a second reference value used for the threshold value processing is set on the basis of a reference light receiving signal output from the light receiving unit during the control. apparatus. The image forming apparatus according to claim 1 or 2,
The light source of the light emitting unit is turned on only at the time of initialization at the time of power-on, and includes means for storing a reference light reception signal received at this time,
The image forming apparatus, wherein the power saving control unit uses the stored reference light reception signal continuously for setting the first or second reference value of the threshold processing until the power is turned off. The image forming apparatus according to any one of claims 1 to 3,
An image forming apparatus, comprising: a light emitting portion provided so that the light receiving portion can directly receive light emitted from the light emitting portion at a close position. The image forming apparatus according to any one of claims 1 to 3,
An image comprising a reference reflecting portion, wherein the reference reflecting portion and the light emitting portion are provided so that the light receiving portion can receive light emitted from the light emitting portion reflected by the reference reflecting portion. Forming equipment. An image forming unit that forms an image on an image carrier based on image data, a light receiving unit that can receive external light and outputs a detection value corresponding to the amount of received light, and emits reference light according to a command by an input operation It has a light source that can be turned on, and has a light emitting unit provided so that light from the light source can be received by the light receiving unit, and a first reference value set in advance with respect to the detection value of the light receiving unit A control method in an image forming apparatus that performs threshold value processing and performs control to shift from a power supply state at the time of image formation to a power supply state at the time of power saving when it falls below a first reference value.
A light receiving signal obtained by adding reference light to external light obtained when the light source of the light emitting unit is turned on is corrected by an external light receiving signal obtained when the light source of the light emitting unit is not turned on. Find the light reception signal,
A control method comprising: setting a first reference value used for the threshold processing in a control for shifting from a power supply state at the time of image formation to a power supply state at the time of power saving based on the obtained reference light receiving signal.

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