JP3871629B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus that forms an image on a sheet such as a copying machine, a facsimile machine, and a printer, and more particularly, to an image forming apparatus that switches supply and stop of power to a site that consumes a large amount of power according to a schedule.
[0002]
[Prior art]
The conventional image forming apparatus can supply power to all parts involved in image formation while the main switch (power switch) is set to ON, and can form an image immediately in response to an instruction. Was kept in standby mode. However, this is not a preferable control method from the viewpoint of reducing power consumption. Therefore, a power-saving mode is provided to reduce power consumption by stopping power supply to parts with high power consumption, including parts that are involved in image formation. Is automatically switched to the power saving mode.
[0003]
In recent years, an image forming apparatus has a function of automatically switching between a standby mode and a power saving mode according to a schedule determined based on the possibility of using the apparatus in order to improve convenience while reducing power consumption. It is also done. The time period when the device is likely to be used varies depending on the user, and even for the same user, it varies depending on the day of the week. Therefore, the user can arbitrarily set the switching time between standby mode and power saving mode for each day of the week. To be able to. Also, an RTC (real time clock) that outputs the real time is provided for the switching.
[0004]
The image forming apparatus is provided with a control unit including a CPU for controlling the operation of each unit of the apparatus including image formation, and switching between the standby mode and the power saving mode is also performed by the control unit that controls the entire apparatus. Is called. Naturally, the power supply to the control unit is continued even in the power saving mode.
[0005]
The RTC has a built-in battery and can always output the actual time. Since the CPU of the control unit that controls the operation of the entire apparatus is complicated and diverse, it needs to be configured by many systems. In such an apparatus, a second CPU is provided in order to share complicated work between the two CPUs in terms of cost and performance.
[0006]
In such a configuration, the actual time given from the RTC by the first CPU of the control unit via the second CPU for switching from the standby mode to the power saving mode and from the power saving mode to the standby mode. Will be based on.
[0007]
[Problems to be solved by the invention]
However, since the second CPU that supplies the output of the RTC to the first CPU also consumes power, if the time for switching from the power saving mode to the standby mode is always determined based on the actual time, the power saving mode is set. The effect of providing and reducing the power consumption is not always sufficiently obtained. In order to avoid this inconvenience, the power supply to the second CPU may be stopped in the power saving mode, but it is not possible to switch from the power saving mode to the standby mode simply by doing so.
[0008]
The present invention has been made in view of such a problem, and even if the control unit that switches between the standby mode and the power saving mode cannot directly use the real time, the switching can be surely performed. An object of the present invention is to provide an image forming apparatus that consumes less power in the power saving mode.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, power is supplied to all parts involved in image formation, and a standby mode in which an image can be formed immediately, and power supply to a predetermined part. Has a power saving mode in which the power consumption is lower than that of the standby mode, the switching time between the standby mode and the power saving mode is stored, and the standby mode and the power saving mode are stored according to the stored time. Is an image forming apparatus that outputs an actual time, a control unit that switches between a standby mode and a power saving mode according to the actual time from the output unit, and an actual time that the output unit outputs A power supply mode that includes a first mode for supplying power to the supply means and a second mode for not supplying power to the supply means. In addition, there is provided a timer means for outputting a signal at a constant time interval and giving it to the control means, and when the control means is in the standby mode, the actual time given from the donating means has reached the switching time to the power saving mode. Sometimes, the mode is switched to the second mode of the power saving mode, and when in the second mode of the power saving mode, the time is estimated based on the output signal of the timer means, and the estimated time is determined from the switching time to the standby mode. Is switched to the first mode of the power saving mode when the predetermined time has passed, and when in the first mode of the power saving mode, the actual time given from the donating means reaches the switching time to the standby mode It shall be switched to the standby mode.
[0010]
In this image forming apparatus, the first mode and the second mode are provided in the power saving mode. In the second mode, power is not supplied to the supplying unit that gives the control unit the actual time from the output unit. Thus, power consumption in the power saving mode can be reduced. In addition, in the second mode, the control means estimates the time based on a signal given from the timer means at a constant time interval, switches to the first mode before the switching time to the standby mode, and based on the actual time. Therefore, it is possible to switch to the standby mode and to perform the switching at an accurate time.
[0011]
The timer means outputs a signal at a constant time interval. If there is an error in the time interval, the estimated time deviates from the true real time when the error is accumulated. Even in such a case, the device is surely set to the standby mode when the switching time has arrived, because the supplying means is operated by switching to the first mode a predetermined time before the stored switching time. can do. The predetermined time may be determined according to the accuracy of the timer means and the length of the power saving mode period. In the configuration using the CPU as the control means and the providing means, a clock circuit that gives them a clock signal that serves as a reference for operation timing can be used as the timer means.
[0012]
Here, when the control means is in the second mode of the power saving mode, based on the output signal of the timer means, the control means is temporarily switched to the first mode every predetermined elapsed time, and the estimated time is provided. It is preferable to correct based on the actual time given. In this way, even when the period of the power saving mode is long, the standby mode can be surely set when the switching time comes without increasing the predetermined time. The period of the first mode that is temporarily switched in the middle of the second mode only needs to be long enough for the control means to acquire the actual time, and can be very short. There is almost no increase in power consumption by temporarily switching to the first mode.
[0013]
The image forming apparatus can store the switching time between the standby mode and the power saving mode on each day of the week. For example, even when the power saving mode is switched to the standby mode only from Monday to Friday and the power saving mode is maintained on Saturday and Sunday, the standby mode can be set at the switching time on Monday.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a digital copying machine as an embodiment of an image forming apparatus of the present invention will be described with reference to the drawings. FIG. 1 schematically shows the overall configuration of the copying machine 1 of the present embodiment. The copying machine 1 includes a main unit 2 that forms an image on a sheet, and a finisher unit 3 that performs predetermined post-processing on the sheet on which the image is formed and discharges the sheet.
[0015]
The main unit 2 includes a forming unit 10 that forms an image on a sheet, a supply unit 20 that supplies the sheet to the forming unit 10, a reading unit 30 that reads an original image, and a transfer unit that transfers the sheet on which the image is formed to the finisher unit 3. 40 and an operation / display unit 50 that is operated by the user and displays information.
[0016]
The forming unit 10 exposes the photosensitive drum 11, the charging unit 12 that charges the photosensitive drum 11, and the charged photosensitive drum 11 to irradiate light partially to remove static electricity, thereby forming a latent image on the photosensitive drum 11. A transfer unit 15 for transferring an image (toner) of the photosensitive drum 11 developed on the supplied sheet; a transfer unit 15 for transferring toner; It comprises a charge removing unit 16 that removes remaining toner from the subsequent photosensitive drum 11 and removes the charge, and a fixing unit 17 that fixes the image on the sheet by pressing while heating.
[0017]
The supply unit 20 includes a plurality of paper feed trays 21 and a plurality of transport rollers 20a. The reading unit 30 includes a scanner 31 and a document feeder (ADF) 32 that sequentially transfers documents to the scanner 31. The scanner 31 outputs the read image as digital image data. The transfer unit 40 includes a plurality of transport rollers 40a.
[0018]
The finisher unit 3 includes a punch unit 60 that opens holes for binding later, a stapler unit 70 that binds a plurality of sheets by staples, a separation unit 80 that separates sheets, a conveyance roller 3a, and a stapler unit 70 that binds sheets. An intermediate tray 3b for placing sheets is provided. The punch unit 60 and the stapler unit 70 operate only when an instruction is given via the operation / display unit 50.
[0019]
The sorting unit 80 includes a plurality of trays 81 that receive sheets. The trays 81 are arranged side by side in the vertical direction and can be moved in the vertical direction. By moving the tray 81 and switching the tray 81 positioned at the end of the sheet transfer path by the transport roller 3a, the sheets are separated. The finisher unit 3 can be attached to and detached from the main unit 2, and when the finisher unit 3 is not attached, the sheet transferred by the transfer unit 40 is directly discharged from the main unit 2.
[0020]
Although not shown, the copying machine 1 includes a photosensitive drum 11, a fixing roller of the fixing unit 17, a motor for driving each conveyance roller, and a transmission mechanism for transmitting the driving force in the main unit 2. I have. In addition, a motor for moving the tray 81 and a motor for driving the punch unit 60 and the stapler unit 70 are provided in the finisher unit 3.
[0021]
A circuit configuration of the copying machine 1 is schematically shown in FIG. Among the above-described units, the scanner 31 includes an illumination optical system 31a that illuminates a document image, and a CCD line sensor 31b that reads the illuminated document image. The operation / display unit 50 includes a plurality of keys 51 including a numeric keypad, a liquid crystal display 52, and a light emitting diode (LED) lamp 53. The key 51 is operated by the user to give an instruction to the copying machine 1. The liquid crystal display 52 displays characters and figures to notify the user of the state of the copying machine 1 and to guide the operation. The LED lamp 53 notifies the state of the copying machine 1 depending on whether it is turned on or off. The forming unit 10 includes a laser scanning system 13 a as a part of the exposure unit 13 and a heater 17 a as a part of the fixing unit 17.
[0022]
In addition, the copier 1 supplies power to a hard disk drive (HDD) 90 having a hard disk for storing image data, a control unit 100 that controls the operation of the entire apparatus including image formation, and each unit that operates with power. A power supply unit 110 is provided.
[0023]
The control unit 100 includes a data copy unit 101, a first CPU 102, a second CPU 103, a memory 104, an RTC 105, a clock circuit 106, and an interface (I / F) 107. The data copy unit 101 processes image data representing an image. Specifically, the image data given from the scanner 31 is stored in the hard disk of the HDD 90, the image data is read from the hard disk, the read image data is appropriately processed, and the laser scanning system is based on the processed image data. The operation of 13a is controlled.
[0024]
The first CPU 102 controls the overall operation of the copying machine 1 including some processes relating to image formation. For example, the operation of the charging unit 12, the developing unit 14, the fixing unit 17, etc. of the forming unit 10, the sheet supply by the supply unit 20, the image reading by the reading unit 30, and the sheet transfer by the transfer unit 30 are controlled. The CPU 102 also controls the operations of the punch unit 60, the stapler unit 70, and the sorting unit 80 of the finisher unit 3 and the power supply from the power supply unit 110.
[0025]
The second CPU 103 gives a signal representing the actual time output from the RTC 105 to the first CPU 102. The RTC 105 has a built-in battery, operates with its power, and constantly outputs a signal representing the actual time. The clock circuit 106 has a built-in oscillator, and outputs a clock signal used as a reference for operation timing by the first and second CPUs 102 and 103.
[0026]
The memory 104 includes a ROM that stores a program describing the control of the first CPU 102 and a RAM that temporarily stores parameters used by the CPU 102 for control. The ROM includes a rewritable flash memory, and parameters that can be changed by the user are written in the flash memory.
[0027]
The copying machine 1 supplies power to all parts, and in a standby mode in which an image can be formed immediately in response to an instruction from the user, and does not supply power to some parts and is more power than the standby mode. It has a power saving mode with low consumption. The power supply line from the power supply unit 110 is divided into two systems as shown in FIG. In the standby mode, power is supplied from both the power supply line A that is not shaded and the power supply line B that is shaded, and in the power saving mode, power supply from the power supply line B is stopped. .
[0028]
The parts connected to the power supply line A and constantly supplied with power include the operation key 51 and LED lamp 53 of the operation / display unit 50, and the first CPU 102, memory 104 and clock 106 of the control unit 100. . In addition, the parts connected to the power supply line B and in which the power supply is stopped in the power saving mode include the forming unit 10, the supply unit 20, the reading unit 30, the transfer unit 40, the liquid crystal display 52 of the operation / display unit 50, The entire finisher unit 3, the HDD 90, and the second CPU 103 of the control unit 100 are included.
[0029]
The copying machine 1 has a function of automatically switching from a standby mode to a power saving mode when a state in which no image is formed continues for a predetermined time in order to reduce power consumption. In this case, cancellation of the power saving mode, that is, return to the standby mode is instructed by an operation of a predetermined operation key 51. Switching between the standby mode and the power saving mode is performed by the first CPU 102.
[0030]
The copier 1 also has a function of storing the switching time between the standby mode and the power saving mode for each day of the week and switching between the standby mode and the power saving mode according to the stored time. The switching time from the standby mode to the power saving mode and the switching time from the power saving mode to the standby mode are stored in the flash memory in the ROM of the memory 104 and can be changed by the user. This switching is also performed by the first CPU 102.
[0031]
The appearance of the display / operation unit 50 is shown in FIG. As described above, the display / operation unit 50 is provided with the key 51, the liquid crystal display 52, and the LED lamp 53. The key 51 includes a numeric keypad 51a for inputting numerical values of 0 to 9, a start key 51b for instructing start of image forming operation, a power saving mode release key 51c for instructing switching from the power saving mode to the standby mode, and the like. ing. The LED lamp 53 includes a power lamp 53a indicating that the main switch (power switch) is on and a power saving mode lamp 53b indicating that the main switch (power switch) is in the power saving mode.
[0032]
The liquid crystal display 52 displays information relating to image formation and overall operation. FIG. 3 shows an example of the state in the standby mode. The liquid crystal display 52 is in a state in which the original image can be read and the image can be formed on a sheet, and three identical images are formed. In addition to this, items indicating on which size sheet an image is formed, what size (magnification) the image is formed, and what density the image is formed are displayed. In addition, a menu item “detailed setting” for setting or confirming the operation is also displayed. The liquid crystal display 52 is configured as a touch panel that detects a pressed part, and the user can specify the item by pressing the part on which the item is displayed.
[0033]
In the state of FIG. 3, when the item “power management” is designated by the user, the display on the liquid crystal display 52 is changed, and the time until switching to the power saving mode when no image is formed is set. A screen for setting and a screen for setting the switching time between the standby mode and the power saving mode for each day of the week are displayed.
[0034]
FIG. 4 shows an example of a screen for setting the switching time between the standby mode and the power saving mode for each day of the week. Corresponding to each day of the week, “ON time” for switching from the power saving mode to the standby mode and “OFF time” for switching from the standby mode to the power saving mode are displayed. These times can be changed by operating the items displayed on the right side. It is also possible not to set the time. In the example of FIG. 4, neither “on time” nor “off time” is set for Saturday and Sunday. In this case, the power saving mode is maintained throughout the day on Saturday and Sunday.
[0035]
As described above, the first CPU 102 switches between the standby mode and the power saving mode, and the CPU 102 uses the actual time output by the RTC 105 to determine the switching time. Here, the output of the RTC 105 is given to the first CPU 102 via the second CPU 103. Since the second CPU 103 is supplied with power from the power supply line B, power is supplied over the entire period of the power saving mode. If the power supply from the line B is stopped, the first CPU 102 cannot use the actual time output by the RTC 105 in order to determine when to switch from the power saving mode to the standby mode.
[0036]
Therefore, in the copying machine 1, in the power saving mode, in addition to the mode in which power is supplied only from the power supply line A, a mode in which power is supplied from both the power supply line A and the power supply line B is set. The power supply from the power supply line B is started before switching to the standby mode. Hereinafter, a mode in which power is supplied from both the power supply line A and the power supply line B is referred to as a first mode, and a mode in which power is supplied only from the power supply line A is referred to as a second mode.
[0037]
When the copying machine 1 is in the standby mode, the first CPU 102 enters the power saving mode when the actual time given from the second CPU 103 reaches the switching time to the power saving mode stored in the memory 104. Switch to the second mode. At that time, the actual time of the switching is stored in the memory 104.
[0038]
The first CPU 102 also counts the clock signal from the clock circuit 106 when the copying machine 1 is in the second mode of the power saving mode, measures the elapsed time in the power saving mode, and stores the stored power saving. The time is estimated from the switching time to the mode and the elapsed time in the power saving mode, and the mode is switched to the first mode when the estimated time reaches a predetermined time before the switching time to the standby mode. As a result, the second CPU 103 operates and the first CPU 102 can obtain the actual time from the RTC 105. After switching to the first mode in this way, the first CPU 102 switches to the standby mode when the actual time given from the second CPU 103 reaches the switching time to the standby mode.
[0039]
With this series of processing, it is possible to achieve both reduction of power consumption by stopping power supply to the second CPU 103 and switching from the power saving mode to the standby mode, and always supply power to the second CPU 103. As in the case of performing, the switching to the standby mode can be performed at an accurate time.
[0040]
In general, an oscillator used in a clock circuit oscillates at a constant period, but there is a slight difference in the period for each oscillator even if the oscillators are of the same standard. For this reason, the cycle of the signal output from the clock circuit is also different for each clock circuit. Therefore, the elapsed time measured by the first CPU 102 is affected by an error in the output cycle of the clock circuit 106, and an error also occurs in the time estimated that the elapsed time becomes too long.
[0041]
In the copying machine 1, even if an error occurs in the estimated time, in order to surely switch from the power saving mode to the standby mode, as described above, from the switching time to the standby mode. Is also switched to the first mode only a predetermined time ago. This predetermined time is, for example, 3 minutes. This is a value determined in consideration of an error in the oscillation period allowed by a standard oscillator and that the period of the power saving mode is normally about 10 hours.
[0042]
However, as in the example illustrated in FIG. 4, the period of the power saving mode may exceed 24 hours, and in this case, the estimated time error may increase as the above predetermined time is exceeded. When such a situation occurs, switching to the first mode becomes later than the switching time to the standby mode, and switching to the standby mode is not performed, or conversely, switching to the first mode is quicker. It becomes too much and invites unnecessary power consumption.
[0043]
In order to prevent such an inconvenience, the copying machine 1 temporarily switches from the second mode to the first mode at every predetermined elapsed time from the switching to the power saving mode, and the first mode. During this time, the actual time from the RTC 105 is given from the second CPU 103 to the first CPU 102 to correct the estimated time. Specifically, the CPU 102 stores the latest actual time in the memory 103 and newly measures the elapsed time from that time.
[0044]
The predetermined elapsed time is, for example, 24 hours. This is a value determined in consideration of an oscillation period error allowed by a standard oscillator and the above-described predetermined time for making the switching to the first mode faster than the switching to the standby mode. . Note that the length of the standby mode period to be temporarily switched is sufficient for the second CPU 103 to start the operation and give the actual time to the first CPU 102, and is extremely short. The power consumption is hardly increased by temporarily switching to the standby mode.
[0045]
FIG. 5 shows a flow of processing in which the first CPU 102 switches between the standby mode and the power saving mode according to the stored time. This process starts when in standby mode.
[0046]
First, the actual time Ta output by the RTC 105 is acquired from the second CPU 103 (# 105), and it is determined whether or not the actual time Ta is the off time Ts to be switched to the power saving mode, and the off time Ts is reached. If not, wait (step # 110). If the actual time Ta becomes the off time Ts, the units other than the control unit 100 are set in a non-operating state (# 115), and the actual time Ta is stored in the memory 104 as the actual switching time Tc to the second mode. (# 120). Further, the predetermined time ti (for example, the above-mentioned 24 hours) is added to the actual time Ta, and the obtained time is stored in the memory 104 as the time Tu for which the calculated time is to be corrected (# 125). Next, the second CPU 103 is stopped (# 130), the power supply from the power supply line B is stopped, and the mode is switched to the second mode of the power saving mode (# 135).
[0047]
After switching to the second mode, the first CPU 102 counts the elapsed time from the output signal of the clock circuit 106, and calculates the current time T0 from this and the time Tc stored in step # 120 (# 140). . Then, it is determined whether or not the calculated time T0 is a predetermined time tb (for example, the above-mentioned 3 minutes) before the on time Tw to be switched to the standby mode (# 145), and must be before the predetermined time tb. For example, it is determined whether or not the calculated time T0 is the time Tu stored in step # 125 (# 150). If the time T0 is the time Tu, a process of correcting the calculated time T0 is performed (# 155). If the time T0 is not the time Tu, the process returns to step # 140 without performing the process.
[0048]
If it is determined in step # 145 that the calculated time T0 is a predetermined time tb before the time Tw, power is also supplied from the power supply line B to switch to the first mode (# 160). Then, the real time Ta output from the RTC 105 is acquired from the second CPU 103 (# 165), and the real time Ta becomes the on time Tw after waiting for the real time Ta to become the on time Tw (# 170). At that time, the mode is switched to the standby mode (# 175).
[0049]
FIG. 6 shows the flow of the correction process at the time T0 calculated in step # 155. First, power is also supplied from the power supply line B to switch to the first mode (step # 205). Next, the real time Ta is acquired from the second CPU 103 (# 210), and this is stored in the memory 104 as the actual switching time Tc to the second mode (# 215), and at a predetermined time ti at the real time Ta. And the obtained time is stored in the memory 104 as a time Tu to be corrected for the calculated time T0 (# 220). Then, the second CPU is stopped (# 225), the power supply from the power supply line B is stopped, and the mode is switched to the second mode (# 230).
[0050]
FIG. 7 shows the flow of the current time T0 calculation process in step # 140 and the actual time Ta acquisition process in steps # 105 and # 165. First, it waits for 1 second to pass based on the output signal of the clock circuit 106 (step # 305), and determines whether the mode is the second mode or the first mode (# 310). In the second mode, 1 second is added to the current time T0 (# 315), and in the first mode, the actual time Ta is obtained from the second CPU 103 (# 320).
[0051]
In the copying machine 1 of the present embodiment, the second CPU 103 that gives the actual time output from the RTC 105 to the first CPU 102 is one that has a stop function for stopping its own operation while receiving power. . Then, as performed in step # 130 of FIG. 5 and step # 225 of FIG. 6, before switching from the first mode to the second mode, that is, while supplying power to the second CPU 103, The second CPU 103 is caused to execute a stop function to stop the operation of the second CPU 103.
[0052]
Depending on the CPU, the operation when the power supply is cut off becomes unstable. If the second CPU 103 is such, the first CPU 102 is switched to the second mode when switching to the second mode. This is because an erroneous real time may be given and the first CPU 102 may not be switched to the power saving mode. If the second CPU 103 is stopped at the time of switching to the second mode, no signal including an erroneous actual time is given to the first CPU 102.
[0053]
FIG. 8 and FIG. 9 show the flow of stop processing of the second CPU 103 at step # 130 and step # 225. 8 shows processing performed by the first CPU 102, and FIG. 9 shows processing performed by the second CPU 103.
[0054]
As shown in FIG. 8, the first CPU 102 first notifies the second CPU 103 that preparations should be made in preparation for switching to the second mode (step # 405). Then, it waits for notification of the end of preparation from the second CPU 103 (# 410), and if there is a notification of completion of preparation, notifies the second CPU 103 that the operation should be stopped (# 415). ). Then, it waits for 10 milliseconds to elapse (# 420). Thereafter, in step # 135 or # 230, the power supply to the second CPU 103 is stopped.
[0055]
As shown in FIG. 9, the second CPU 103 repeatedly determines whether or not there is a notification from the first CPU 102 (step # 505). Then, when notified, it is determined whether or not it is an instruction for preparation (# 510), and if it is an instruction for preparation, the operation of its own predetermined part is stopped (# 515). ) Notify the first CPU 102 that the preparation is completed (# 520), and return to step # 505. If the notification is not an instruction for preparation, it is determined whether or not a stop is instructed (# 525). If the instruction is not a stop, the process returns to step # 505. If the notification is a stop instruction, the operation of all of its parts is stopped (# 530). Thereafter, when the power supply is stopped and restarted, the second CPU 103 performs its own initialization process and starts a normal operation.
[0056]
In the present embodiment, an example is shown in which the switching time from the standby mode to the power saving mode and the switching time from the power saving mode to the standby mode are each stored once a day. A plurality of mode switching times may be stored in one day. By doing so, for example, it becomes possible to set the power saving mode at night and during lunch break, and the power consumption can be further reduced. In that case, the predetermined time for making the switching from the second mode to the first mode faster than the switching to the standby mode can be made shorter than the illustrated three minutes.
[0057]
Furthermore, the second CPU having a stop function and controlling the second CPU to stop the operation before stopping the power supply to the second CPU is not limited to the time processing. The present invention can be applied when the CPU is used for any other processing. Although a copying machine has been described here as the image forming apparatus of the present invention, the present invention can also be applied to other image forming apparatuses such as a facsimile and a printer.
[0058]
【The invention's effect】
Power is supplied to all the parts involved in image formation and the standby mode in which an image can be formed immediately, and the power supply to a predetermined part is stopped, and power consumption is higher than in standby mode. An image forming apparatus having a power saving mode in a low state, storing a switching time between the standby mode and the power saving mode, and switching between the standby mode and the power saving mode according to the stored time. Output means, a control means for switching between the standby mode and the power saving mode according to the actual time from the output means, and a providing means for giving the control means the actual time output by the output means. As in the invention, in the power saving mode, a first mode for supplying power to the supplying means and a second mode for not supplying power to the supplying means are provided, and at a constant time interval. Timer means for outputting a signal to the control means, and when the control means is in the standby mode, when the real time given from the providing means reaches the time for switching to the power saving mode, When switching to the mode 2 and in the second mode of the power saving mode, the time is estimated based on the output signal of the timer means, and the estimated time reaches a predetermined time before the switching time to the standby mode Sometimes, switching to the first mode of the power saving mode, and when in the first mode of the power saving mode, when the real time given from the donating means reaches the switching time to the standby mode, the mode is switched to the standby mode. Then, it is possible to reliably and accurately switch from the power saving mode to the standby mode while suppressing power consumption in the power saving mode.
[0059]
When the control means is in the second mode of the power saving mode, based on the output signal of the timer means, the control means is temporarily switched to the first mode every predetermined elapsed time, and the estimated time is given from the providing means. If the correction is made based on the actual time, the timer means has an error, and even when the period of the power saving mode is long, the switching time does not change too quickly from the second mode to the first mode. Can be surely switched to the standby mode when.
[0060]
If the switching time between the standby mode and the power saving mode on each day of the week is stored, there is a high possibility that the device is set to the standby mode when the user wants to use it, and convenience is improved.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing an overall configuration of a digital copying machine according to an embodiment of the present invention.
FIG. 2 is a block diagram schematically showing a circuit configuration of the copying machine.
FIG. 3 is a diagram showing an example of the appearance of a display / operation unit of the copying machine.
FIG. 4 is a view showing an example of a display screen for setting a switching time between a standby mode and a power saving mode for each day of the week in the copying machine.
FIG. 5 is a flowchart showing a flow of processing for switching according to a time when the first CPU of the copying machine stores a standby mode and a power saving mode.
6 is a flowchart showing a flow of a correction process for the calculated time in step # 155 of FIG.
7 is a flowchart showing a flow of a current time calculation process in step # 140 of FIG. 5 and a real time acquisition process in steps # 105 and # 165.
FIG. 8 is a flowchart showing a flow of stop processing of the second CPU in step # 130 of FIG. 5 and step # 225 of FIG. 6;
FIG. 9 is a flowchart showing a flow of processing performed by a second CPU corresponding to the processing of FIG. 8;
[Explanation of symbols]
1 Digital copier
2 Main unit
3 Finisher unit
3a Transport roller
3b Intermediate tray
10 Formation part
11 Photosensitive drum
12 Charging part
13 Exposure section
13a Laser scanning system
14 Development section
15 Transfer section
16 Static neutralizer
17 Fixing part
17a heater
20 Supply section
20a Conveying roller
21 Paper tray
30 Reading unit
31 Scanner
31a Illumination optical system
31b CCD line sensor
32 Document feeder
40 Transfer section
40a Conveying roller
50 Operation / display section
51 Operation keys
51a numeric keypad
51b Start key
51c Power saving mode release key
52 Liquid crystal display
53 LED lamp
53a Power lamp
53b Power saving mode lamp
60 Punch
70 Stapler
80 sorting section
81 trays
90 hard disk drive
100 Control unit
101 Data copy section
102 first CPU
103 second CPU
104 memory
105 RTC (real time clock)
106 Clock circuit
107 interface

Claims (3)

Power is supplied to all the parts involved in image formation and the standby mode in which an image can be formed immediately, and power supply to a predetermined part is stopped, and power consumption is higher than in standby mode. An image forming apparatus having a power saving mode in a low state, storing a switching time between the standby mode and the power saving mode, and switching between the standby mode and the power saving mode according to the stored time. Output means for outputting, control means for switching between the standby mode and the power saving mode according to the actual time from the output means, and a providing means for giving the control means the actual time output by the output means,
The power saving mode includes a first mode for supplying power to the supplying means and a second mode for not supplying power to the supplying means,
Timer means for outputting a signal at a constant time interval and giving it to the control means;
The control means
When in the standby mode, when the real time given from the providing means reaches the switching time to the power saving mode, the mode is switched to the second mode of the power saving mode,
When in the second mode of the power saving mode, the time is estimated based on the output signal of the timer means, and when the estimated time reaches a predetermined time before the switching time to the standby mode, Switch to the first mode,
An image forming apparatus that switches to a standby mode when an actual time given from a donating unit reaches a switching time to a standby mode when in the first mode of the power saving mode. When the control means is in the second mode of the power saving mode, based on the output signal of the timer means, the control means is temporarily switched to the first mode every predetermined elapsed time, and the estimated time is given from the providing means. The image forming apparatus according to claim 1, wherein correction is performed based on actual time. The image forming apparatus according to claim 1, wherein a switching time between the standby mode and the power saving mode on each day of the week is stored.

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