JP2009294314A - Image forming apparatus and control method for the same, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus securing productivity which matches a user's requirement by effectively using power stored in a capacitor without spending unnecessary cost for the apparatus. <P>SOLUTION: The image forming apparatus displays whether or not to give priority to productivity, for a user who uses the apparatus at high duty after returning to a standby mode from a sleep mode and consequently requires power which cannot be covered by the charged amount of the capacitor 1005, Then, when productivity is given the priority, the user is requested to set return starting time from the next sleep mode onward. Then, return to the standby mode from the sleep mode is started at the time which is obtained by adding the operation time at the charged amount of the capacitor 1005 calculated at the point of transition into the sleep mode to the time requiring the power supply from the capacitor 1005 at the point of returning from the sleep mode. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image forming apparatus, a control method thereof, and a program, and more particularly, to an image forming apparatus using a DC power source and a secondary battery that can be charged by a DC power source as a power source, a control method thereof, and a program.

  Conventional image forming apparatuses typified by electrophotographic copying machines are designed to cope with the increase in copying speed, and by making the copying system multi-functional including applications such as automatic document feeders and sorting devices. Electricity consumed when the machine is in operation tends to increase. Therefore, in order to keep the rated power of the copying machine within a predetermined value, for example, a restriction is placed on the power supplied to the heating means of the fixing device.

  As a means for keeping the rated power of the copying machine within a predetermined value, for example, the surplus power of the apparatus is stored in a secondary battery such as an electric double layer capacitor (hereinafter simply referred to as “capacitor”), and power is required. There has been proposed a form of discharging during the image forming operation (see Patent Document 1). Moreover, the form performed based on the built-in time recognition information etc. as a timing of the charge of the capacitor is proposed (refer patent document 2). In addition, there has been proposed a control for fully charging the capacitor when the main power of the apparatus is turned off.

  On the other hand, when the fixing device is completely cooled, the power consumption as the apparatus is maximized when returning from the sleep mode set for energy saving of the copying machine to the standby mode. FIG. 9 shows the relationship between fixing power and time required when the apparatus is started from a state in which the fixing device is completely cooled.

  In FIG. 9, fixing power of Pf2 or more is required before time Tp when the fixing device and the apparatus main body are sufficiently warmed up, but Pf2 is sufficient after time Tp. Immediately after returning from the sleep mode to the standby mode, if an operation requiring discharge from the capacitor is continuously performed, there is a possibility that the amount of power charged in the capacitor is used up. When the amount of power charged in the capacitor is exhausted, the productivity of the device, such as reducing the input power to the fixing unit or reducing the number of images to be formed per unit time so that the entire device is below the specified power. It becomes a situation that must be dealt with by dropping. FIG. 10 shows the relationship between the apparatus power of the copying machine and time.

In FIG. 10, the apparatus power Pt is the maximum power of the copying machine that can be applied from the AC input. Before the time Tp when the fixing device and the apparatus main body are sufficiently warmed up, power Pt1 equal to or greater than Pt is required, but after time Tp, Pt is sufficient. Therefore, if the power Pt1 used as the device can be used from the time immediately after startup to the time Tcp using the power Pc (= Pt1-Pt) from the capacitor, the operation can be performed while maintaining the maximum productivity.
JP 2002-280146 A Japanese Patent Laid-Open No. 2000-116033

  However, even if power is stored in the capacitor, the amount of power stored is limited by the capacity of the equipped capacitor. In addition, it is burdensome to install a capacitor with a large capacity in terms of apparatus cost.

  For example, in FIG. 10, when the capacitor can store only the time Tcp, the energy that can be stored in the capacitor is Tcp × Pc. For this reason, when the capacitor is discharged from immediately after startup until time Tcp, no further discharge from the capacitor is possible. Further, the productivity of the apparatus can be improved by reducing the input power to the fixing device or reducing the number of images formed per unit time so that the time Td between Tcp and Tp is less than the specified power for the entire apparatus. It will be inevitable to deal with it by dropping it.

  In view of the above problems, the present invention provides an image forming apparatus that can effectively use power stored in a capacitor and ensure productivity that meets a user's request without incurring unnecessary apparatus costs, and a control method therefor, The purpose is to provide a program.

  In order to achieve the above object, the image forming apparatus according to claim 1, in the image forming apparatus having a rechargeable secondary battery as one of the power sources, a voltage detection unit that detects a voltage of the secondary battery; When the detected voltage of the secondary battery is lower than a predetermined value, image forming means for performing an image forming operation in a productivity down mode for reducing power supply to a load, and image formation in the productivity down mode is performed. The time setting means for allowing the user to set a desired return time from the sleep mode to the standby mode in which the image forming operation can be performed to reduce the power consumption of the image forming apparatus, and the return desired set by the time setting means Based on the time, a calculating means for calculating a return start time from the sleep mode to the standby mode, a time measuring means for measuring the time, the calculated time and the previous time If the timed time match, characterized in that from the sleep mode and a control means for starting the return to the standby mode.

  In order to achieve the above object, the image forming apparatus control method according to claim 7 includes a voltage detection step of detecting a voltage of the secondary battery, and a case where the detected voltage of the secondary battery is lower than a predetermined value. In addition, an image forming process that performs an image forming operation in a productivity down mode that reduces power supply to a load, and a sleep that reduces power consumption of the image forming apparatus when image formation is performed in the productivity down mode. A time setting step for allowing the user to set a desired return time to the standby mode in which an image forming operation can be performed from the mode, and a return from the sleep mode to the standby mode based on the desired return time set in the time setting step When the calculation step for calculating the start time, the time measurement step for measuring the time, and the calculated time and the time measured match, the sleep mode is set. And a controlling step of starting the return to the standby mode.

  According to the present invention, it is possible to effectively use the power stored in the capacitor without incurring unnecessary device costs, and to ensure productivity that meets the user's request.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[First Embodiment]
FIG. 1 is a schematic diagram showing an internal configuration of an image forming apparatus according to the first embodiment of the present invention.

  In FIG. 1, the image forming apparatus includes a reader unit 301 that reads a document image and a printer unit 302 that prints the read image on paper. The reader unit 301 includes a document table 310, a document pressure plate 311, a lamp 312, a mirror group 313, a lens 314, a CCD 315, an image processing unit 401, and the like.

  In the reader unit 301, the document placed between the document table 310 and the document pressure plate 311 is scanned in the arrow V direction while the lamp 312 irradiates the document. The reflected light image from the original is imaged on a CCD 315 that has been subjected to RGB three color filters through a mirror group 313 and a lens 314, and is photoelectrically converted by the CCD 315 into RGB signals. The image signal that has become an electrical signal is subjected to predetermined image processing in the image processing unit 401, and CMYK output image data is created and sent to the printer unit 302.

  The printer unit 302 includes a printer control unit 326, a polygon scanner 325, and image forming units 331, 332, 333, and 334. The printer control unit 326 performs image control and drive control in the apparatus. The polygon scanner 325 scans the photosensitive drum with laser light. The image forming unit 331 is a first-stage magenta (M) image forming unit. The image forming units 332, 333, and 334 have the same configuration as the image forming unit 331, and are image forming units for each color of cyan (C), yellow (Y), and black (K). The printer control unit 326 performs image conversion processing and performs predetermined gamma correction on the image data. Laser elements 321 to 324 that are independently driven in accordance with the image data subjected to gamma correction scan the photosensitive drums in the image forming units 331 to 334 with a laser beam.

  Since the image forming units 331 to 334 all have the same configuration, the structure and function thereof will be described using the image forming unit 331.

  The image forming unit 331 includes a photosensitive drum 340 that forms a latent image by laser light exposure. Around the photosensitive drum 340, a developing device 341, a primary charger 344, a cleaner 345, an auxiliary charger 346, a pre-exposure lamp 347, a transfer charger 348, and a development density sensor 349 are arranged.

  The developing device 341 is a developing device that performs toner development on the photosensitive drum 340. The developing unit 341 includes a developing sleeve 342 that applies a developing bias and performs toner development. The developer concentration sensor 343 detects the developer concentration based on the amount of light reflected from the developer on the developing sleeve 342. The primary charger 344 charges the photosensitive drum 340 to a desired potential. The cleaner 345 cleans the surface of the photosensitive drum 340 after transfer. The auxiliary charger 346 discharges the surface of the photosensitive drum 340 cleaned by the cleaner 345 so that the primary charger 344 can obtain good charge. The pre-exposure lamp 347 erases residual charges on the photosensitive drum 340. The transfer charger 348 discharges from the inside of the transfer belt 354 and transfers the toner image on the photosensitive drum 340 to a transfer member. The development density sensor 349 detects the amount of reflected light from the development formed on the photosensitive drum 340.

  On the other hand, the transfer sheets 3511 and 3521 are stored in the sheet storage units 351 and 352, and are fed and conveyed from there. The registration roller 361 once stops the transfer sheet, and determines the transfer sheet conveyance timing to the image forming units 331 to 334. After the conveyance timing is taken by the registration roller 361, the transfer sheet is sent onto the transfer belt 354. Then, the magenta image is formed on the transfer paper by transferring the toner image formed on the photosensitive drum 340 onto the transfer paper conveyed by the transfer belt 354. By performing this electrophotographic process in the same manner for each image forming unit for cyan, yellow, and black, a color image corresponding to the original is formed on the transfer paper.

  The image-formed transfer sheet passes through the pre-fixing conveyance 355 and is conveyed to the fixing device 356. Then, the toner image is heated and fixed on the transfer paper by the fixing device 356 and output as an image on the transfer paper. In the case of performing reverse-side paper discharge in which the image surface is turned over and discharged, the transfer sheet is conveyed to the reverse conveyance path 357, reversed by the reverse conveyance path 357, and then discharged. On the other hand, in the mode in which double-sided image formation is performed, the transfer sheet on which the image has been formed is conveyed from the reverse conveyance path 357 to the refeeding conveyance path 358 and sent to the refeeding apparatus 350 to form the image on the second side. Arranged as a sheet to do. The printer unit 302 includes a manual sheet feeding device 353 in addition to the sheet storage 360 including the sheet storage units 351 and 352.

  FIG. 2 is a block diagram showing a schematic configuration of a charge / discharge control circuit including a power source and a capacitor in the image forming apparatus of FIG.

  The commercial power supply 1000 is connected to the current detection unit 1002 from the outside of the image forming apparatus, and is connected to the power supply unit 1003 via the current detection unit 1002. The current detection unit 1002 measures the charging current It flowing from the commercial power supply 1000 and notifies the control unit 1001 of it. A control unit 1001 controls the apparatus. Note that the power supply to the control unit 1001 is supplied by another power supply unit (not shown).

  The power supply unit 1003 mainly supplies power to the load unit 1010 in the apparatus. The power supply unit 1003 supplies power by converting the power from the commercial power supply 1000 into DC power based on the control signal Cp from the control unit 1001. The power supply unit 1003 is connected to the charging control unit 1004 and the switching unit 1007. The charging control unit 1004 charges the capacitor 1005 by applying a DC current controlled based on the control signal Ic from the control unit 1001 to the capacitor 1005.

  The capacitor 1005 is connected to the switching unit 1007 via the voltage detection unit 1006 (voltage detection means). The output voltage of the capacitor 1005 is detected by the voltage detection unit 1006 and notified to the control unit 1001 as the voltage Vc. The switching unit 1007 outputs either the power from the capacitor 1005 or the power from the power source unit 1003 to the DC / DC converter 1008 based on the control signal P / C from the control unit 1001.

  The DC / DC converter 1008 converts the output voltage from the switching unit 1007 into a predetermined voltage and outputs it. The output current from the DC / DC converter 1008 is monitored by the current detection unit 1009 and used as drive power for the load unit 1010. The monitor value Iu is notified from the current detection unit 1009 to the control unit 1001.

  The load unit 1010 is a general term for drive units that perform various operations in the reader unit 301 and the printer unit 302 in the apparatus. The output voltage Vc from the capacitor 1005 varies depending on the charged power. A DC / DC converter 1008 is required to convert the electric power having the varying voltage into a predetermined voltage that can be used by the load unit.

  The control unit 1001 is connected to an operation unit (not shown), and performs the above-described image formation control and power supply control based on a program and a set value stored in a built-in memory according to an input to the operation unit. In addition, the control unit 1001 has a time measuring unit that measures the current time, measures the standby duration in which the standby mode is continued, and shifts from the standby mode to the sleep mode when the standby duration exceeds a predetermined time. Mode control such as transition is performed.

  Next, the charge / discharge control operation in the charge / discharge control circuit of FIG. 2 will be described.

  The power supply unit 1003 is normally activated by the control signal Cp from the control unit 1001 and performs output. Based on the control signal P / C from the control unit 1001, the switching unit 1007 outputs the input from the power supply unit 1003 as an output, and connects the input from the capacitor 1005 so as to be disconnected from the output, and loads via the DC / DC converter 1008. Output to unit 1010.

  At the time of charging, when the operating current It of the entire device is not more than a predetermined value in anticipation of the increase in current at the time of charging, it is detected that the capacitor voltage Vc is not more than the predetermined value and the charging mode for charging the capacitor 1005 To do. The charging current It is a current value instructed by the charging control unit 1004 based on the control signal Ic from the control unit 1001 in a range where the monitor value Iu detected by the current detection unit 1009 does not exceed the rating of the power supply unit 1003. Is controlled at a constant current.

  At the time of discharging, when the operating current It of the entire device exceeds a predetermined value, it is detected that the capacitor voltage Vc exceeds the predetermined value, and the discharge mode for discharging the capacitor 1005 is entered. The charging to the capacitor 1005 is stopped by instructing the charging control unit 1004 from the control unit 1001 to zero current by the control signal Ic. Based on the control signal P / C, the switching unit 1007 outputs the input from the capacitor 1005 as an output, connects the input from the power supply unit 1003 to the output, and outputs it to the load unit 1010 via the DC / DC converter 1008. I do.

  If the discharge output from the capacitor 1005 exceeds a predetermined value based on the charge capacity and the capacitor voltage Vc becomes equal to or lower than the predetermined value, the switching unit 1007 receives the input from the power supply unit 1003 based on the control signal P / C. Connect for output. Then, output is performed to the load unit 1010 via the DC / DC converter 1008. At the same time, control such as reducing the throughput of image formation is performed so that the operating current It of the entire apparatus becomes a predetermined value or less.

  In a state where charging / discharging from the capacitor 1005 is not performed, the electric power charged in the capacitor 1005 is held. Actually, since power is consumed in a minute amount due to loss in the capacitor or the like, the power stored in the capacitor 1005 decreases with time.

  At the time of shifting to the energy saving mode (power reduction mode) of the apparatus, the control unit 1001 detects that the image formation or reading operation has not been performed for a predetermined time or longer, and turns off the control signal Cp to the power supply unit 1003. Then, the output of the power supply unit 1003 is turned off, and the power consumed by the load unit 1010 is eliminated, so that low power consumption and energy saving can be realized as a device. The device is returned from the energy saving mode by turning on the control signal Cp to the power supply unit 1003 based on the input of the return request to the control unit 1001.

  Next, in an operation that requires discharging from the capacitor 1005, when it is detected that the charging voltage of the capacitor 1005 is equal to or lower than a specified value, a process for performing productivity priority setting will be described with reference to FIG.

  FIG. 3 is a flowchart illustrating a control process when productivity priority setting is performed in the image forming apparatus.

  First, the control unit 1001 sets “0” to a flag Cemp that becomes “1” when the capacitor 1005 cannot be discharged (step S1001). Next, when a copy operation is requested to the image forming apparatus (YES in step S1002), the process proceeds to step S10003.

  In step S1003, an elapsed time t after returning from the sleep mode to the standby mode is determined, and it is determined whether or not t is equal to or less than a predetermined time TP (step S1003). Sleep mode is a mode that puts the device in a state that reduces power consumption. The standby mode is a mode in which the apparatus is in a state where an image forming operation can be performed.

  If the elapsed time t after returning from the sleep mode has exceeded the predetermined time TP (NO in step S1003), the process proceeds to step S1005. In step S1005, fixability can be ensured even if the power supply to the fixing device is equal to or less than a predetermined value, and the operating power of the load unit 1010 is less than the specified power even if only the power from the power supply unit 1003 is output. Become. Therefore, the copy operation is performed in the capacitor holding operation mode in which the capacitor 1005 holds the electric charge. Then, the control unit 1001 determines whether or not the copy operation is finished, and when finished, this process is finished.

  On the other hand, if the elapsed time t after returning from the sleep mode has not exceeded the predetermined time TP (step S1003 YES), the power required for the operation of some of the load units 1010 is supplemented with the stored power of the capacitor 1005. Become. Then, the control unit 1001 detects the voltage Vc of the capacitor 1005 by the voltage detection unit 1006 (step S1007). Next, when Vc is equal to or higher than the voltage VL necessary for the operation of some of the load units 1010 (NO in step S1008), the copy operation is performed in the capacitor discharge mode in which the capacitor 1005 discharges to some of the load units 1010. Is performed (step S1009).

  In step S1008, when voltage Vc of capacitor 1005 is lower than voltage VL necessary for the operation of some load units 1010 (YES in step S1008), the process proceeds to step S1010. In step S1010, since the capacitor 1005 cannot be discharged, a copy operation is performed in the productivity down mode in which the operation of the load unit 1010 is partially stopped or the power supply to the fixing device is reduced (step S1010). Here, the flag Cemp = 1 is set.

  Next, when the copy operation ends (YES in step S1011), the control unit 1001 determines whether or not the flag Cemp = 1 (step S1012). If the flag Cemp = 1 (YES in step S1012), it is determined that the capacitor 1005 cannot be discharged. Then, the control unit 1001 displays a screen for allowing the user to set whether to give priority to productivity shown in FIG. 4A to be described later on an operation unit (not shown) (step S1013). When the control unit 1001 determines that the setting for giving priority to productivity has been performed (YES in step S1014), the control unit 1001 sets “1” indicating productivity priority in the productivity priority flag ST (step S1015). Then, the control unit 1001 displays a return start time setting screen for allowing the user to set the return start time from the sleep mode to the standby mode shown in FIG. 4B (step S1015). When the user sets the return start time from the sleep mode to the standby mode on the screen shown in FIG. 4B, the set return start time is stored as the desired return time Top from the sleep mode (step S1015). ), This process is terminated.

  FIG. 4 is a diagram illustrating an example of a screen displayed on the operation unit in the process of FIG. 3, (a) is a screen for allowing the user to set whether to prioritize productivity, and (b) is from the sleep mode. This is a screen for allowing the user to set the return start time.

  In FIG. 4A, when the energy saving button 1501 is selected and the decision button 1503 is pressed, the productivity priority flag ST in step S1015 in FIG. 3 is “0”. On the other hand, when the productivity button 1502 is selected and the enter button 1503 is pressed, the productivity priority flag ST is “1”.

  When the productivity button 1502 is selected on the screen shown in FIG. 4A and the determination button 1503 is pressed and the productivity priority flag ST becomes 1, the operation unit switches to the screen shown in FIG. 4B. . On the screen, buttons 1511 and 1512 for selecting whether to return from the sleep mode to the standby mode every day or from Monday to Friday, and buttons 1513 to 1516 for setting the return start time are arranged. When the enter button 1517 is pressed while the return start time is set, the contents set on the screen are stored as the desired return time Top from the sleep mode.

  FIG. 5 is a flowchart showing control processing at the time of transition to the sleep mode and at the time of return.

  First, the control unit 1001 acquires a flag STO indicating that the return has been performed by the timer giving priority to productivity, and determines whether or not STO = 1 (step S2001). When the flag STO = 1, that is, when the control unit 1001 determines that the return by the timer giving priority to productivity is performed during the previous image forming operation (YES in step S2001), the process proceeds to step S2002. In step S2002, TSL2 is set as the standby duration TSL until the standby mode is shifted to the sleep mode (step S2002). Here, TSL2 is set to a value larger than the warm-up time Tp required after returning from the sleep mode to the standby mode.

  On the other hand, the control unit 1001 sets TSL1 as the standby duration TSL when the flag STO = 0, i.e., when it is determined that the return by the timer giving priority to productivity is not performed in the previous time (step S2003). Since TSL1 has not been restored by a timer that prioritizes productivity, it has a lower value than TSL2.

  Next, the control unit 1001 compares the time ts measured as the standby continuation time by a timing unit (not shown) in the control unit 1001 with the set TSL (step S2004). If the measured time ts is equal to or longer than the standby duration TSL (YES in step S2004), the control unit 1001 acquires the productivity priority flag ST and determines whether ST = 1 (step 1). S2005). When the productivity priority flag ST is a value “1” indicating productivity priority (YES in step S2005), the return start time Tops from the sleep mode is calculated (step S2006), and the standby mode is switched to the sleep mode. Migration is performed (step S2007). On the other hand, if the productivity priority flag ST is not “1” in step S2005, the process proceeds to step S2007 as it is. A method of calculating the return start time Tops from the sleep mode in step S2006 will be described later.

  Next, the control unit 1001 acquires the productivity priority flag ST, and determines whether ST = 1 (step S2008). When the productivity priority flag ST is “1” indicating productivity priority (YES in step S2008), the control unit 1001 matches the time Tc timed by the time measuring means with the return start time Tops from the sleep mode. It is determined whether or not it has been done (step S2009).

  On the other hand, when the productivity priority flag ST is “0” indicating energy saving priority (NO in step S2008), or when the time Tc does not match the return start time Tops from the sleep mode (NO in step S2009), It progresses to step S2012. In step S2012, the control unit 1001 determines whether there is a request for return from the sleep mode. If there is a return request (YES in step S2012), the control unit 1001 sets “0” in the flag STO (step S2013), and performs a return operation from the sleep mode (step S2011).

  On the other hand, when the time Tc matches the return start time Tops from the sleep mode (YES in step S2009), the control unit 1001 sets “1” in the flag STO (step S2010). Then, a return operation from the sleep mode to the standby mode is performed (step S2011).

  Next, a method for calculating the return start time Tops from the sleep mode in step S2006 of FIG. 5 will be described.

  The predicted remaining voltage value Vc1 of the capacitor 1005 at the desired return time Top is obtained from the time Tc1 at the time of transition to the sleep mode, the stored desired return time Top and the remaining capacitor voltage Vc at the time of transition to the sleep mode. In the capacitor 1005 left in the sleep mode, the electric charge is consumed with time by a coefficient α determined by the balance with the peripheral circuit, so that the voltage at the present time and the voltage after the leaving time elapse can be calculated.

Vc1 = Vc−α (Top−Tc1)
Next, a time Tcp (first time) during which power can be supplied from the capacitor 1005 is calculated from the predicted capacitor remaining voltage value Vc1 at the time of desired return time Top. The time Tcp can be calculated from the remaining power amount and the proportional coefficient β.

Tcp = β × Vc1 ^ 2
In addition, the time Tp (second time) required to supply power from the capacitor 1005 at the time of returning from the sleep mode is uniquely determined from the fixing capability of the apparatus. As a result, the return start time Tops from the sleep mode is a time that is advanced by (Tp−Tcp) from the return desired time Top, as shown in FIG.

  FIG. 6 is a diagram illustrating the relationship between the apparatus power and time of the image forming apparatus when returning from the sleep mode to the standby mode.

  The device power Pt is the maximum power that can be applied from the AC input. Before the time Tp when the fixing device and the apparatus main body are sufficiently warmed up, power Pt1 equal to or greater than Pt is required, but after time Tp, Pt is sufficient. Therefore, a time Tcp during which power can be supplied from the capacitor 1005 is calculated, and a time that is advanced by (Tp−Tcp) from the desired return time Top is set as the return start time Tops from the sleep mode. As a result, after the desired return time Top, power can be supplied from the capacitor 1005, and an image forming operation can be performed without reducing the productivity of the apparatus.

  In addition, for the user who uses the apparatus with a high duty after returning from the sleep mode to the standby mode and uses the capacity that cannot be compensated for by the amount of charge of the capacitor 1005, whether or not to give priority to productivity is displayed. When productivity is prioritized, the return start time from the sleep mode after the next time is set. Then, the sleep mode is switched to the standby mode at a time when the operation time at the charge amount of the capacitor 1005 calculated at the time of transition to the sleep mode is added to the time when the power supply from the capacitor 1005 is required when returning from the sleep mode. Start returning. As a result, it is possible to operate the apparatus without reducing productivity by adding a minimum standby duration.

  On the other hand, it is possible to realize productivity that makes use of the charge amount of the capacitor 1005 without burdening an excessive capacitor for a user who uses a duty that is compensated by the charge amount of the capacitor 1005.

  In the present embodiment, when the capacitor voltage becomes equal to or lower than the specified value, a setting screen is displayed that allows the user to set whether to give priority to productivity. When productivity priority is selected, the return start time from the sleep mode is set. The form in which the setting is validated has been described. However, this is not a limitation. That is, a setting unit for enabling the setting of the return start time from the sleep mode may be separately provided, and the return start time setting from the sleep mode may be enabled when the setting is made.

[Second Embodiment]
About the part similar to 1st Embodiment, the description is abbreviate | omitted using the same code | symbol. Only differences from the first embodiment will be described below.

  FIG. 7 is a block diagram showing a schematic configuration of a charge / discharge control circuit including a power source and a capacitor of an image forming apparatus according to the second embodiment of the present invention.

  The image forming apparatus according to the second embodiment is obtained by adding an environmental temperature detection unit 2001 to the image forming apparatus of FIG. 2 in the first embodiment, and the other components are the first. Since this is the same as the embodiment, the description thereof is omitted.

  The environmental temperature detection unit 2001 includes a temperature detection element such as a thermistor, and is connected to the control unit 1001. The environmental temperature detection unit 2001 measures the environmental temperature Te at which the apparatus is placed and notifies the control unit 1001. The control unit 1001 includes a correlation table between the environmental temperature Te and the time Tu that requires power supply from the capacitor 1005 as shown in FIG. In the correlation table, as shown in the figure, when the environmental temperature Te is in the range of Te1 to Te2, the time Tu that requires the power supply from the capacitor 1005 is Tu1, and similarly, Tu2 in the range of Te2 to Te3. , Te3 in the range of Te3 to Te4.

  The control unit 1001 refers to the correlation table based on the environmental temperature Te notified from the environmental temperature detection unit 2001, and calculates a time Tu that requires power supply from the capacitor 1005. Note that the calculation method of the time Tu may be performed by calculation by linear approximation or the like in addition to the calculation method by the correlation table between the environmental temperature Te and the time Tu shown in FIG. Further, the time Tu that requires power supply from the capacitor 1005 may be the time Tp when the above-described fixing device and the apparatus main body are sufficiently warmed up.

  According to the second embodiment, the ambient temperature in which the apparatus is placed is measured, and the result is taken into account in calculating the time Tu that requires power supply from the capacitor 1005. As a result, it is possible to calculate the time Tu that requires power supply from the capacitor 1005 with higher accuracy and the return start time Tops from the sleep mode.

[Third Embodiment]
The image forming apparatus according to the third embodiment of the present invention has the same configuration (FIGS. 1 to 2) as that of the image forming apparatus according to the first embodiment. About the same part, the description is abbreviate | omitted using the same code | symbol. Only differences from the first embodiment will be described below.

  In the present embodiment, control unit 1001 calculates capacitance C of capacitor 1005 that decreases with time from the relationship between charging current It and charging voltage Vc of capacitor 1005 when capacitor 1005 is charged. Then, the result is used to calculate the time Tcp during which power can be supplied from the capacitor 1005.

  The maximum charging voltage Vc0 of the capacitor 1005 is determined by the type of the capacitor 1005 to be used, and is charged until the charging voltage Vc = Vc0 is satisfied during charging. The energy that can be stored in the capacitor 1005 is represented by 0.5 × C × V ^ 2. At this time, even when charging with the same charging current It from the same capacitor voltage to the maximum charging voltage Vc0, the time required to store the capacitor 1005 becomes longer if the capacitance C of the capacitor 1005 is large. By measuring this time, the capacitance C of the capacitor 1005 can be calculated.

  The energy that can be stored in the capacitor 1005 is proportional to the capacitance C of the capacitor 1005, as can be seen from the above formula. From this, if the capacitance C of the capacitor 1005 can be calculated, the time Tcp during which power can be supplied from the capacitor 1005 determined by the energy that can be stored in the capacitor 1005 can be calculated.

  According to the third embodiment, the capacitance C of the capacitor 1005 that decreases with time is calculated from the relationship between the charging current It and the charging voltage Vc of the capacitor 1005. This makes it possible to calculate the time Tcp during which power can be supplied from the capacitor 1005 with higher accuracy and the return start time Tops from the sleep mode.

[Fourth Embodiment]
The image forming apparatus according to the fourth embodiment of the present invention has the same configuration (FIGS. 1 to 2) as that of the image forming apparatus according to the first embodiment. About the same part, the description is abbreviate | omitted using the same code | symbol. Only differences from the first embodiment will be described below.

  In the present embodiment, the control unit 1001 calculates the capacity of the capacitor 1005 that decreases with time based on the charging duration of the capacitor 1005, and the result is the time during which power can be supplied from the capacitor 1005. Consider the calculation of Tcp.

  The capacitor 1005 has a larger capacity drop as the time during which a higher voltage is applied is longer. Therefore, a value Vct obtained by temporally accumulating the charging voltage Vc of the capacitor 1005 is calculated. The capacitance C of the capacitor 1005 is expressed by the following equation where the initial capacitance C0 and the coefficient γ are given.

C = C0 (1-γ * Vct)
If the capacitance C of the capacitor 1005 can be calculated, the time Tcp during which power can be supplied from the capacitor 1005 determined by the energy that can be stored in the capacitor 1005 can be calculated.

  According to the fourth embodiment, the capacitance C of the capacitor 1005 that decreases with time is calculated from the value obtained by accumulating the charging voltage Vc of the capacitor 1005 over time. This makes it possible to calculate the time Tcp during which power can be supplied from the capacitor 1005 with higher accuracy and the return start time Tops from the sleep mode.

  The flag described in the above embodiment is stored in a memory (not shown) in the control unit 1001 and is read by a CPU (not shown) in the control unit 1001 as necessary.

  The object of the present invention is achieved by executing the following processing. That is, a storage medium that records a program code of software that realizes the functions of the above-described embodiments is supplied to a system or apparatus, and a computer (or CPU, MPU, etc.) of the system or apparatus is stored in the storage medium. This is the process of reading the code. In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiment, and the program code and the storage medium storing the program code constitute the present invention.

  Moreover, the following can be used as a storage medium for supplying the program code. For example, floppy (registered trademark) disk, hard disk, magneto-optical disk, CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD + RW, magnetic tape, nonvolatile memory card, ROM or the like. Alternatively, the program code may be downloaded via a network.

  Further, the present invention includes a case where the function of the above-described embodiment is realized by executing the program code read by the computer. In addition, an OS (operating system) running on the computer performs part or all of the actual processing based on an instruction of the program code, and the functions of the above-described embodiments are realized by the processing. Is also included.

  Furthermore, a case where the functions of the above-described embodiment are realized by the following processing is also included in the present invention. That is, the program code read from the storage medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer. Thereafter, based on the instruction of the program code, the CPU or the like provided in the function expansion board or function expansion unit performs part or all of the actual processing.

1 is a schematic diagram illustrating an internal configuration of an image forming apparatus according to a first embodiment of the present invention. FIG. 2 is a block diagram illustrating a schematic configuration of a charge / discharge control circuit including a power supply and a capacitor in the image forming apparatus of FIG. 1. 6 is a flowchart illustrating a control process when productivity priority setting is performed in the image forming apparatus. FIG. 4 is a diagram illustrating an example of a screen displayed on the operation unit in the process of FIG. 3, where (a) is a screen for allowing the user to set whether to prioritize productivity, and (b) is a return start time from the sleep mode. It is a screen for making a user set. It is a flowchart which shows the control processing at the time of sleep mode transfer and return. FIG. 4 is a diagram illustrating a relationship between apparatus power and time of an image forming apparatus when returning from a sleep mode to a standby mode. FIG. 5 is a block diagram illustrating a schematic configuration of a charge / discharge control circuit including a power supply and a capacitor of an image forming apparatus according to a second embodiment of the present invention. It is a figure which shows an example of the correlation table of environmental temperature Te and time Tp which requires the electric power supply from a capacitor. FIG. 6 is a diagram illustrating a relationship between fixing power and time required when the apparatus is started from a state where the fixing device is completely cooled. It is a figure which shows the relationship between the apparatus electric power of conventional copying machines, and time.

Explanation of symbols

1000 Commercial power supply 1001 Control unit 1002, 1009 Current detection unit 1003 Power supply unit 1004 Charge control unit 1005 Capacitor 1006 Voltage detection unit 1007 Switching unit 1008 DC / DC converter 1010 Load unit

Claims (13)

In an image forming apparatus having a rechargeable secondary battery as one of power sources,
Voltage detecting means for detecting the voltage of the secondary battery;
An image forming unit that performs an image forming operation in a productivity down mode that reduces power supply to a load when the detected voltage of the secondary battery is lower than a predetermined value;
When image formation is performed in the productivity down mode, a time setting unit that allows the user to set a desired return time from the sleep mode to reduce the power consumption of the image forming apparatus to the standby mode in which the image forming operation can be performed;
Calculating means for calculating a return start time from the sleep mode to the standby mode based on the desired return time set by the time setting means;
A time measuring means for measuring time;
An image forming apparatus comprising: a control unit that starts returning from the sleep mode to the standby mode when the calculated time and the measured time coincide with each other.   The image forming apparatus according to claim 1, wherein the calculating unit calculates the return start time from the desired return time, a time when the mode is shifted to the sleep mode, and a voltage of the secondary battery.   The calculation means calculates a first time during which power can be supplied from the secondary battery from the predicted remaining voltage value of the secondary battery at the desired return time, and requires power supply from the secondary battery. 3. The image forming apparatus according to claim 1, wherein a time that is advanced from the desired return time by a time obtained by subtracting the first time from the second time is calculated as the return start time. A temperature detecting means for measuring an environmental temperature where the image forming apparatus is placed;
The image forming apparatus according to claim 3, wherein the calculating unit calculates the second time according to an environmental temperature detected by the temperature detecting unit, and calculates the return start time. A current detection means for measuring a charging current to the secondary battery;
The calculating means calculates the capacity of the secondary battery based on the measured charging current and the charging voltage of the secondary battery, calculates the second time from the result, and calculates the return start time. The image forming apparatus according to claim 3, wherein the image forming apparatus is calculated. And further comprising accumulating means for accumulating the charging voltage to the secondary battery,
The calculation means calculates a capacity of the secondary battery based on the accumulated charging voltage, calculates the second time from the result, and calculates the return start time. Item 4. The image forming apparatus according to Item 3. In a control method of an image forming apparatus having a rechargeable secondary battery as one of power sources,
A voltage detection step of detecting a voltage of the secondary battery;
An image forming step of performing an image forming operation in a productivity down mode for reducing power supply to a load when the detected voltage of the secondary battery is lower than a predetermined value;
When image formation is performed in the productivity down mode, a time setting step for allowing the user to set a desired return time from the sleep mode to reduce the power consumption of the image forming apparatus to the standby mode in which the image forming operation can be performed;
A calculation step of calculating a return start time from the sleep mode to the standby mode based on the desired return time set in the time setting step;
A clocking process for clocking time,
A control method comprising: a control step of starting return from the sleep mode to the standby mode when the calculated time and the measured time coincide with each other.   The control method according to claim 7, wherein the calculating step calculates the return start time from the return desired time, a time at the time of transition to the sleep mode, and a voltage of the secondary battery.   The calculation step calculates a first time during which power can be supplied from the secondary battery from the predicted remaining voltage value of the secondary battery at the desired return time, and requires power supply from the secondary battery. 9. The control method according to claim 7, wherein a time that is advanced from the desired return time by a time obtained by subtracting the first time from the second time is calculated as the return start time. A temperature detecting step of measuring an environmental temperature where the image forming apparatus is placed;
The control method according to claim 9, wherein the calculating step calculates the second time according to the environmental temperature detected in the temperature detecting step and calculates the return start time. A current detection step of measuring a charging current to the secondary battery,
The calculating step calculates the capacity of the secondary battery based on the measured charging current and the charging voltage of the secondary battery, calculates the second time from the result, and calculates the return start time. The control method according to claim 9, wherein the control method is calculated. A further accumulating step of accumulating a charging voltage to the secondary battery;
The calculating step calculates the capacity of the secondary battery based on the accumulated charging voltage, calculates the second time from the result, and calculates the return start time. Item 10. The control method according to Item 9.   A computer-readable program for causing a computer to execute the control method according to any one of claims 7 to 12.

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