JP6158621B2 - Image forming apparatus and image forming method - Google Patents

Description

  The present invention relates to an image forming apparatus and an image forming method, and more particularly to an image forming apparatus and an image forming method for performing a waiting process for counting clocks of a control unit.

Conventionally, there are image forming apparatuses such as multifunction peripherals (MFPs) capable of printing documents and images.
Some processing programs executed by a control unit such as a CPU of these image forming apparatuses count the clock of the control unit and perform a waiting process.
In such a waiting process, when the power of the control means is always on, it is possible to calculate the waiting time accurately by counting the clock, and no particular problem occurs. However, once the control means enters a power saving state such as a sleep state, the clock count does not advance, and a waiting time shift occurs.

Referring to Patent Document 1, a clock generated by a CR oscillation circuit is input to a frequency dividing circuit that can select a frequency dividing ratio, a frequency dividing ratio is set, and a reference period signal is generated by a clock generated by a crystal oscillation circuit. There is disclosed an image forming apparatus comprising means for generating and correcting a startup time setting register value from a ratio of a period of a clock signal output from a frequency dividing circuit and a reference period signal.
The technique of Patent Document 1 can accurately correct the period of the sleep state in a microcomputer including a startup timer that operates based on a low-speed and high-frequency variation clock generated by the CR oscillation circuit.

JP 2011-06159 A

  However, the technique of Patent Document 1 cannot measure the clock count when the circuit that generates the clock introduced to the control unit is stopped in the first place, and as a result, the waiting time shift cannot be resolved. It was.

  The present invention has been made in view of such a situation, and an object thereof is to provide an image forming apparatus that solves the above-described problems.

The image forming apparatus of the present invention includes a control unit that counts a clock in a normal startup state and holds it as a clock count value, and a real-time clock unit that measures time and holds it as a time value even when the control unit enters a power saving state. An image forming apparatus comprising a storage unit stores a return time value, and returns the control unit from the power saving state when the return time value is reached in conjunction with the time value of the real-time clock unit. A power saving return timer unit, a reference time value acquisition unit that acquires a time value of the real-time clock unit as a reference time value in the normal activation state of the control unit, and the control unit before the power saving state The reference time acquired by the reference time value acquisition unit when waiting processing for measuring elapsed time based on the clock count value of the control unit is performed. An elapsed time calculation unit that calculates an elapsed time of the waiting process based on the value and the time value of the real-time clock unit at the time of return from the power saving state, and the control unit obtains the reference time value After obtaining the reference time value by the unit, a clock count value is obtained until the time value of the real-time clock unit changes by 1 second, and the obtained clock count value is expressed in seconds including a value after the decimal point. Converted to a value, subtracts the converted value from 1, calculates a fraction of less than 1 in seconds until the reference time value is obtained, and if this fraction is less than 0.5 seconds, The reference time value acquired in the storage unit is stored as it is by rounding down the fraction. If this fraction is 0.5 seconds or more, the fraction is rounded up, the reference time value is incremented by 1, and the wait time is Together When starting the processing, the control unit (1) obtains a time value of the real-time clock unit and stores it in the storage unit as a start time value, and (2) the power saving by the elapsed time calculation unit. It is determined whether or not a transition to the power saving state is performed, and it is determined whether or not a timer return is necessary when the transition to the power saving state is performed. The return time value is set in the timer unit, and (3) when the return time value is set, the time value of the real-time clock unit is changed from the clock count value when the state is shifted to the power saving state. By subtracting the clock count value, the return time fractional value is calculated and stored in the storage unit, the transition to the power saving state is performed, and (4) the return from the power saving state to the normal startup state is started. When , The time value of the real time clock unit acquired at the time of return, by comparing the start time value stored in the storage unit and calculates the elapsed time from the start of the waiting process, the clock count value, is calculated (5) The elapsed time calculation unit determines whether or not the timer has been restored. If the timer has been restored, the return time fraction value stored in the storage unit is acquired. And adding to the clock count value to which the elapsed time from the start of the waiting process is added .
The image forming method of the present invention includes a control unit that counts a clock in a normal startup state and holds it as a clock count value, and a real-time clock unit that measures time and holds it as a time value even when the control unit enters a power saving state. In the image forming method by the image forming apparatus including the storage unit, the image forming apparatus further stores a return time value, and when the return time value is obtained in conjunction with the time value of the real-time clock unit. A power saving return timer unit that returns the control unit from the power saving state, and a reference time value acquisition unit that acquires a time value of the real-time clock unit as a reference time value in the normal activation state of the control unit; When the control unit has been performing a waiting process for measuring the elapsed time based on the clock count value of the control unit before the power saving state, An elapsed time calculation unit that calculates an elapsed time of the waiting process based on the reference time value acquired by the reference time value acquisition unit and the time value of the real-time clock unit when returning from the power saving state. The control unit obtains the clock count value until the time value of the real-time clock unit changes by 1 second after the reference time value is obtained by the reference time value obtaining unit, and the value of the obtained clock count value Is converted to a value in seconds including a value after the decimal point, and the converted value is subtracted from 1 to calculate a fraction of less than 1 in seconds until the reference time value is obtained. Is less than 0.5 seconds, the fraction is rounded down and the reference time value acquired in the storage unit is stored as it is. If this fraction is 0.5 seconds or more, the fraction is rounded up. In the case where the reference time value is increased by 1 and the waiting process is started, the control unit acquires (1) the time value of the real-time clock unit and stores it in the storage unit as a start time value. 2) The elapsed time calculation unit determines whether or not to shift to the power saving state, determines whether or not it is necessary to perform a timer return when shifting to the power saving state, and the timer When it is necessary to return, the return time value is set in the power saving return timer unit, and (3) when the return time value is set, from the clock count value when shifting to the power saving state Subtracting the clock count value when the time value of the real-time clock unit changes to calculate a return time fraction value, store it in the storage unit, and shift to the power saving state, (4) Above When starting the return from the power saving state to the normal activation state, and the time value of the real time clock unit acquired at the time of return from the start of the queuing process by comparing the start time value stored in the storage unit The elapsed time is calculated, and the calculated elapsed time is added to the clock count value. (5) The elapsed time calculation unit determines whether or not the timer has been restored. The return time fraction value stored in the section is acquired and added to a clock count value to which an elapsed time from the start of the waiting process is added .

  According to the present invention, when the circuit that generates the clock is stopped in the power saving state, the waiting time is calculated by calculating the elapsed time of the waiting process from the reference time value of the real-time clock when returning from the power saving state. Therefore, it is possible to provide an image forming apparatus that reduces the deviation.

1 is a system configuration diagram according to an embodiment of an image forming apparatus of the present invention. FIG. 2 is a block diagram illustrating a control configuration of the image forming apparatus illustrated in FIG. 1. FIG. 2 is a schematic diagram of the image forming apparatus illustrated in FIG. 1. It is a flowchart of the reference time value setting process which concerns on embodiment of this invention. FIG. 5 is a conceptual diagram of rounding up or down processing shown in FIG. 4. It is a flowchart of the waiting process which concerns on embodiment of this invention. It is a conceptual diagram of the start time value preservation | save process and elapsed time calculation process which are shown in FIG. It is a conceptual diagram of the return time end numerical value calculation process and the return time end value correction process shown in FIG. It is a conceptual diagram explaining the case where there is no reference | standard time value of this invention.

<Embodiment>
[System Configuration of Image Forming Apparatus 1]
First, the system configuration of the image forming apparatus 1 will be described with reference to FIG.

  The image forming apparatus 1 includes an image processing unit 11, a document reading unit 12, a document feeding unit 13, a transport unit (paper feed roller 422, transport roller 44, discharge roller 45), network transmission / reception unit 15, operation panel unit 16, storage The unit 19, the image forming unit 17 (image forming unit), the real-time clock unit 20, the power saving return timer unit 30, and the like are connected to the control unit 10. The operation of each unit is controlled by the control unit 10.

The control unit 10 includes a general purpose processor (GPP), a central processing unit (CPU), a micro processing unit (MPU), a digital signal processor (DSP), a graphics processing unit (GPU), and an application specific processor (ASIC). Information processing means such as a processor for a specific application)
The control unit 10 reads out a control program stored in the ROM or HDD of the storage unit 19, develops the control program in the RAM, and executes it to operate as each unit of a functional block described later. Further, the control unit 10 controls the entire apparatus in accordance with predetermined instruction information input from an external terminal (not shown) or the operation panel unit 16.
The control unit 10 includes a timer circuit that counts clocks, and stores the value of the timer circuit as a clock count value 510 (FIG. 2) in a storage unit such as a register. For example, the timer circuit can measure time in units of 1/100 second to 1/10000 second based on the clock frequency. The control unit 10 can control the start and stop of the timer circuit, and can reset the clock count value 510.

In addition, the control unit 10 shifts each unit to an operation mode of a normal activation state and a power saving state. In the normal startup state, the control unit 10 controls each unit with normal power consumption. When a predetermined time such as “power saving transition time” set in the storage unit 19 has elapsed in the normal startup state, the control unit 10 shifts each unit to a power saving state with low power consumption.
In the power saving state, the control unit 10 turns off the power supply of each unit, and the control unit 10 itself also enters a halt state (sleep state) such as HALT. In this power saving state, power supply to peripheral circuits such as a clock supply circuit including a crystal resonator of the control unit 10 is also turned off, so that clock counting cannot be performed. However, the control unit 10 supplies power to the network transmission / reception unit 15, sensors such as the document reading unit 12, the real-time clock unit 20, the power saving return timer unit 30, and the like. The control unit 10 shifts from the low power consumption state to the normal activation state by a return signal from the means to which these power supplies are supplied.

The image processing unit 11 is control arithmetic means such as a DSP (Digital Signal Processor) or a GPU (Graphics Processing Unit). The image processing unit 11 is a unit that performs predetermined image processing on image data, and performs various types of image processing such as enlargement / reduction processing, density adjustment, gradation adjustment, and image improvement processing.
The image processing unit 11 stores the image read by the document reading unit 12 in the storage unit 19 as print data. At this time, the image processing unit 11 can also convert the print data into a file unit in a format such as PDF or TIFF.

The document reading unit 12 is a (scan) unit that reads a set document. The document reading unit 12 can acquire a return signal for returning from the power saving state by a sensor that detects the document, and can transmit it to each unit including the control unit 10.
The document feeding unit 13 is a unit that transports a document read by the document reading unit 12.
The image forming unit 17 is a unit that forms an image on a recording sheet from data stored in the storage unit 19 and read by the document reading unit 12 or acquired from an external terminal according to a user output instruction.
The transport unit transports the recording paper from the paper feed cassette 421 (FIG. 3), causes the image forming unit 17 to form an image, and then transports the recording paper to the stack tray 50.
The operations of the document reading unit 12, the document feeding unit 13, the transport unit, and the image forming unit 17 will be described later.

The network transmission / reception unit 15 is a network connection unit including a LAN board, a wireless transceiver, and the like for connecting to an external network such as a LAN, a wireless LAN, a WAN, and a mobile phone network.
The network transmission / reception unit 15 transmits / receives data on a data communication line and transmits / receives voice signals on a voice telephone line.
The network transmission / reception unit 15 can acquire a return signal for returning from the power saving state and can transmit it to each unit including the control unit 10.

The operation panel unit 16 includes a display unit such as an LCD, a numeric keypad, a start button, a cancel button, a button for switching operation modes such as copying, FAX transmission, and a scanner, and a job for printing, transmission, storage, and recording of a selected document. And an input unit such as a button and a touch panel for giving instructions related to execution.
The operation panel unit 16 can also acquire a return signal for returning from the power saving state from pressing of a button, a touch panel, or the like, or a connected human sensor (not shown), and can transmit it to each unit including the control unit 10.
The operation panel unit 16 acquires instructions for various jobs of the image forming apparatus 1 by the user. It is also possible to input and change information of each user according to user instructions acquired from the operation panel unit 16.

The storage unit 19 is a storage unit that uses a semiconductor memory such as a ROM (Read Only Memory) or a RAM (Random Access Memory) or a recording medium such as an HDD (Hard Disk Drive).
Even if the RAM of the storage unit 19 is in a power saving state, the stored contents are held by a function such as self-refresh.
The storage unit 19 stores each value (FIG. 2) relating to the clock count of the control unit 10. A control program for controlling the operation of the image forming apparatus 1 is stored in the ROM and HDD of the storage unit 19. In addition to this, the storage unit 19 also stores user account settings. The storage unit 19 may include a storage folder area for each user.

  The real-time clock unit 20 is a circuit dedicated to timing such as a real-time clock with a battery backup function that measures time even when the control unit 10 enters a power saving state. For example, the real-time clock unit 20 always measures time in units of seconds using a clock supplied by a crystal oscillation circuit (not shown) provided separately from the control unit 10. This time can be read as a time value 520 (FIG. 2). Further, the time of the real-time clock unit 20 can be changed by the control unit 10.

The power saving return timer unit 30 is means for returning the control unit 10 from the power saving state when the set return time 530 (FIG. 2) is reached. For example, the power saving return timer unit 30 transmits a return signal to the control unit 10 by an interrupt signal or the like at a set time in conjunction with the time of the real-time clock unit 20. As a result, power is supplied to the control unit 10 to turn it on, and a timer return that returns from the power saving state is performed.
Further, the power saving return timer unit 30 transmits a power saving transition signal based on an interrupt signal or the like to the control unit 10 when the set predetermined time has elapsed. The control unit 10 that has received the power saving transition signal shifts each unit to the power saving state.

In the image forming apparatus 1, the control unit 10 and the image processing unit 11 may be integrally formed, such as a CPU with a built-in GPU or a chip-on-module package.
Further, the real-time clock unit 20 and the power saving return timer unit 30 may be integrally formed.
The control unit 10 and the image processing unit 11 may include a RAM, a ROM, a flash memory, and the like.
Further, the image forming apparatus 1 may include a FAX transmission / reception unit that performs facsimile transmission / reception.

[Control Flow of Image Forming Apparatus 1]
Here, the control flow of the image forming apparatus 1 will be described with reference to FIG.
The image forming apparatus 1 includes a reference time value acquisition unit 100 (reference time value acquisition unit) and an elapsed time calculation unit 110 (elapsed time calculation unit).
The control unit 10 updates the clock count value 510 stored in the storage unit such as a register during the waiting process.
The real-time clock unit 20 constantly updates the time value 520 stored in the storage unit in the normal activation state and the power saving state.
The power saving return timer unit 30 sets the return time 530 by the control unit 10. The power saving return timer unit 30 returns the control unit 10 from the power saving state when the time value 520 of the real-time clock unit 20 reaches the return time 530.
The storage unit 19 stores a return time 530, a return time fraction value 540, a reference time value 550, and a start time value 560.

The reference time value acquisition unit 100 acquires the time value 520 of the real-time clock unit 20 as the reference time value 550 in the normal activation state of the control unit 10.
Further, the reference time value acquisition unit 100 rounds up or rounds down a fraction of the reference time value 550, for example, less than 1 second, based on the clock count value 510 of the control unit 10. At this time, the reference time value acquisition unit 100 truncates the clock count value 510 during the interval until the reference time value 550 is increased by 1 second if it is less than half of 1 second, and exceeds half of 1 second. Round up in case.
Further, when the return time 530 is set in the power saving return timer unit 30, the reference time value acquisition unit 100 obtains a return time fraction value 540 that is a fractional value of the return time from the clock count value 510 of the control unit 10. calculate.

The elapsed time calculation unit 110 is a reference acquired by the reference time value acquisition unit 100 when the control unit 10 is performing a waiting process for measuring the elapsed time based on the clock count value 510 of the control unit 10 before the power saving state. The elapsed time of the waiting process is calculated from the time value 550 and the time value 520 of the real-time clock unit 20 when returning from the power saving state.
Further, when the power saving return timer unit 30 returns from the power saving state at the set return time 530, the elapsed time calculation unit 110 corrects the calculated elapsed time of the waiting process by the return time fraction value 540. .

  The clock count value 510 is a value obtained by counting the clock generated and supplied by the control unit 10 by a crystal oscillation circuit (not shown) or the clock generated by a built-in oscillation circuit (not shown). The clock count value 510 is counted at an interval shorter than the time value 520 of the real-time clock unit 20.

  The time value 520 is a value indicating the time at which the real-time clock unit 20 continues to be updated. The time value 520 is stored in a storage unit such as a register of the real-time clock unit 20 as a time value such as year, day, hour, minute, and second in units of one second.

  The return time 530 is a time value of the return time stored in a storage unit such as a register of the power saving return timer unit 30. The return time 530 is set by a control program stored in the storage unit 19. The return time 530 indicates a time in the same unit as the time value 520 set by the real-time clock unit 20, for example. Further, it is possible to set to return at a predetermined interval like an interval timer. Further, the return time 530 may be set by the control unit 10 according to a user instruction from the operation panel unit 16.

  The return time fraction value 540 is a value calculated by the clock count value 510 of the control unit 10 when the return time 530 is set in the power saving return timer unit 30. The return time fraction value 540 is used to calculate the elapsed time more accurately when the return time fraction value 540 is returned by the timer of the power saving return timer unit 30.

  The reference time value 550 is a value of the time value 520 of the real-time clock unit 20 acquired in the normal activation state of the control unit 10. The reference time value 550 is used to calculate the elapsed time of the waiting process. Further, the reference time value 550 is expressed by, for example, a time_t data type.

  The start time value 560 is a value of the time value 520 of the real-time clock unit 20 acquired at the start of the waiting process. When the elapsed time calculation unit 110 calculates the elapsed time of the waiting process, a value obtained by subtracting the reference time value 550 from the start time value 560 is used. The start time value 560 may also be expressed by, for example, the time_t data type.

Here, the control unit 10 of the image forming apparatus 1 functions as the reference time value acquisition unit 100 and the elapsed time calculation unit 110 by executing the control program stored in the storage unit 19.
Each unit of the image forming apparatus 1 is a hardware resource for executing the image forming method of the present invention.

[Operation of Image Forming Apparatus 1]
Next, the operation of the image forming apparatus 1 according to the embodiment of the present invention will be described with reference to FIG.
The document reading unit 12 is arranged on the upper part of the main body unit 14, and the document feeding unit 13 is arranged on the upper side of the document reading unit 12. The stack tray 50 is disposed on the recording paper discharge port 41 side formed in the main body unit 14, and the operation panel unit 16 is disposed on the front side of the image forming apparatus 1.

The document reading unit 12 includes a scanner 12a, a platen glass 12b, and a document reading slit 12c. The scanner 12 a includes an exposure lamp, a CCD (Charge Coupled Device), a CMOS (Complementary Metal Oxide Semiconductor) imaging sensor, and the like, and is configured to be movable in the document transport direction by the document feeder 13.
The platen glass 12b is an original table made of a transparent member such as glass. The document reading slit 12 c has a slit formed in a direction orthogonal to the document transport direction by the document feeding unit 13.

When reading a document placed on the platen glass 12b, the scanner 12a is moved to a position facing the platen glass 12b, and reads the document while scanning the document placed on the platen glass 12b to obtain image data. The acquired image data is output to the main body unit 14.
When reading the document conveyed by the document feeding unit 13, the scanner 12a is moved to a position facing the document reading slit 12c, and the document feeding unit 13 conveys the document through the document reading slit 12c. The document is read in synchronization with the operation to acquire image data, and the acquired image data is output to the main body unit 14.

The document feeding unit 13 includes a document placement unit 13a, a document discharge unit 13b, and a document transport mechanism 13c. The originals placed on the original placement unit 13a are sequentially fed out one by one by the original conveyance mechanism 13c, conveyed to a position facing the original reading slit 12c, and then discharged to the original discharge unit 13b.
The document feeding unit 13 is configured to be retractable, and the upper surface of the platen glass 12b can be opened by lifting the document feeding unit 13 upward.

The main body 14 includes the image forming unit 17, and includes a paper feeding unit 42, a paper conveyance path 43, a conveyance roller 44, and a discharge roller 45. The paper feed unit 42 includes a plurality of paper feed cassettes 421 that store recording papers of different sizes or orientations, and a paper feed roller 422 that feeds the recording papers one by one from the paper feed cassette 421 to the paper transport path 43. Yes. The paper feed roller 422, the transport roller 44, and the discharge roller 45 function as a transport unit. The recording paper is conveyed by this conveyance unit.
The recording paper fed to the paper transport path 43 by the paper feed roller 422 is transported to the image forming unit 17 by the transport roller 44. Then, the recording paper on which recording is performed by the image forming unit 17 is discharged to the stack tray 50 by the discharge roller 45.

  The image forming unit 17 includes a photosensitive drum 17a, an exposure unit 17b, a developing unit 17c, a transfer unit 17d, and a fixing unit 17e. The exposure unit 17b is an optical unit including a laser device, a mirror, a lens, an LED array, and the like. The exposure unit 17b outputs light or the like based on image data to expose the photosensitive drum 17a, and the surface of the photosensitive drum 17a is statically exposed. An electrostatic latent image is formed. The developing unit 17c is a developing unit that develops the electrostatic latent image formed on the photosensitive drum 17a using toner, and forms a toner image based on the electrostatic latent image on the photosensitive drum 17a. The transfer unit 17d transfers the toner image formed on the photosensitive drum 17a by the developing unit 17c to a recording sheet. The fixing unit 17e heats the recording paper on which the toner image is transferred by the transfer unit 17d to fix the toner image on the recording paper.

[Reference Time Value Setting Process by Image Forming Apparatus 1]
Next, a waiting process by the image forming apparatus 1 according to the embodiment of the present invention will be described with reference to FIGS.
In this process, a reference time value 550 for measuring the elapsed time when returning from the power saving state is calculated. This process is performed only once, for example, at the time of a cold boot in which the control unit 10 is normally started after the entire power is turned off.
In the reference time value setting process of the present embodiment, the control unit 10 mainly executes a program stored in the storage unit 19 using hardware resources in cooperation with each unit.
The details of the reference time value setting process will be described step by step with reference to the flowchart of FIG.

(Step S101)
First, the control unit 10 performs a reference time value acquisition process using the reference time value acquisition unit 100.
The control unit 10 acquires the time value 520 of the real-time clock unit 20 as a reference time value in the normal activation state, and stores it in the storage unit 19.
At this time, the control unit 10 starts counting the clock with the clock count value 510.

(Step S102)
Next, the control unit 10 uses the reference time value acquisition unit 100 to round up or round down.
Referring to FIG. 5, after acquiring the reference time value 550, the control unit 10 acquires, for example, the clock count value 510 until the time value 520 of the real-time clock unit 20 changes for 1 second. The control unit 10 converts the acquired clock count value 510 into a value in seconds including a value after the decimal point. For example, the control unit 10 subtracts the converted value from 1, and calculates a fraction of less than 1 in seconds until the reference time value 550 is acquired.
According to FIG. 5A, when the fraction is less than 0.5 seconds, the control unit 10 rounds down the fraction and holds the reference time value 550 acquired in the storage unit 19 as it is.
Further, according to FIG. 5B, when this fraction is 0.5 seconds or more, the control unit 10 rounds up the fraction and increases the reference time value 550 by one.
This makes it possible to calculate a more accurate elapsed time in the waiting process.
Thus, the reference time value setting process according to the embodiment of the present invention is completed.

[Waiting process by the image forming apparatus 1]
Next, a waiting process by the image forming apparatus 1 according to the embodiment of the present invention will be described with reference to FIGS.
This waiting process is a process in which the control unit 10 counts the clock and measures the elapsed time based on the clock count value 510. When the control unit 10 returns to the power saving state, the elapsed time of the waiting process is calculated from the reference time value 550 and the time value 520 of the real time clock at the time of return. Thereby, it is possible to suppress a time lag due to the fact that the count of the clock count value 510 is not increased in the power saving state.
In the reference time value setting process of the present embodiment, the control unit 10 mainly executes a program stored in the storage unit 19 using hardware resources in cooperation with each unit.
Hereinafter, the outline of the waiting process will be described step by step with reference to the flowchart of FIG.

(Step S201)
First, the controller 10 causes the elapsed time calculator 110 to perform a waiting start process.
The control unit 10 starts measuring the time indicated by the clock count value 510 by counting the clock when waiting is required as the processing of the control program stored in the storage unit 19. At this time, the control unit 10 specifies the waiting time and stores it in the storage unit 19.

(Step S202)
Next, the control unit 10 causes the elapsed time calculation unit 110 to perform start time value storage processing.
Referring to FIG. 7, the control unit 10 acquires the time value of the real-time clock time value 520 and stores it in the storage unit 19 as the start time value 560.
At this time, the control unit 10 may perform rounding up or down processing for the start time value 560 by the clock count value 510 as in step S102 (FIG. 4) described above.

(Step S203)
Next, the control unit 10 determines whether or not the elapsed time calculation unit 110 shifts to the power saving state. The control part 10 determines as Yes, when changing to a power saving state by the process of a control program, etc. In other cases, the control unit 10 determines No.
In the case of Yes, the control part 10 advances a process to step S204.
In No, the control part 10 advances a process to step S211.

(Step S204)
In the case of shifting to the power saving state, the control unit 10 determines whether or not it is necessary to return the timer by the elapsed time calculation unit 110. For example, when the control unit 10 returns to the normal activation state at the time set in the power saving return timer unit 30 after shifting to the power saving state, as in a network response, for example, the control unit 10 determines Yes. In other cases, the control unit 10 determines No.
In the case of Yes, the control part 10 advances a process to step S205.
In No, the control part 10 advances a process to step S207.

(Step S205)
When it is necessary to perform the timer recovery, the control unit 10 causes the elapsed time calculation unit 110 to perform a recovery time timer setting process.
The control unit 10 sets a return time 530 in the power saving return timer unit 30 when the power saving return timer unit 30 needs to return to the normal activation state.
In addition, the control unit 10 does not simply set a return time as the return time 530, but, for example, shifts to the power saving state and returns to the normal startup state a plurality of times at the timing of network protocol response or the like. You may set the interval timer etc. which repeat.

(Step S206)
Next, the control unit 10 causes the elapsed time calculation unit 110 to perform return time value calculation processing.
Referring to FIG. 8, the control unit 10 calculates the fractional value of the time value 520 of the real-time clock unit 20 at the time of shifting to the power saving state, based on the clock count value 510, and stores it as the return time fractional value 540 in the storage unit 19. Remember.
For example, the control unit 10 subtracts the clock count value 510 when the time value 520 of the real-time clock unit 20 is changed from the clock count value 510 when the state is shifted to the power saving state. A numerical value 540 is calculated.

(Step S207)
Here, the control unit 10 performs a power saving state transition process using the elapsed time calculation unit 110.
The control unit 10 turns off the power of each unit, stops the operation of the control unit 10 itself, and transitions to a sleep state or the like. During the power saving state, although the clock count is stopped, the clock count value 510 is held.
In the power saving state, the RAM of the storage unit 19 is in a self-refresh state or is transferred to a nonvolatile storage area and the stored data is held.

(Step S208)
Thereafter, the control unit 10 acquires a return signal and starts to return from the low power consumption state to the normal startup state. Then, the control unit 10 performs an elapsed time calculation process using the elapsed time calculation unit 110.
Referring back to FIG. 7, the control unit 10 acquires the time value 520 from the real-time clock unit 20 when returning from the power saving state, and compares the elapsed time with the reference time value 550 stored in the storage unit 19. calculate.
For example, the control unit 10 subtracts the reference time value 550 from the time value 520 acquired at the time of return, and further subtracts the start time value 560 stored in the storage unit 19. The control unit 10 may calculate the elapsed time from the start of the waiting process by multiplying the number of seconds resulting from the subtraction by the value of the clock count value 510 per second.
The control unit 10 adds the calculated elapsed time to the clock count value 510.
As illustrated in FIG. 7, the control unit 10 may calculate the elapsed time every time the controller 10 starts up from the low power consumption state. Also in this case, the control unit 10 calculates the difference based on the reference time value 550, so that the accuracy of the elapsed time calculation is increased as described later.

(Step S209)
Next, the control unit 10 determines whether or not the timer has been returned by the elapsed time calculation unit 110. The control unit 10 determines Yes when the power saving return timer unit 30 returns from the low power consumption state at the set return time 530. The control unit 10 determines No in other cases such as a return from the low power consumption state by a return signal from the network transmission / reception unit 15.
In the case of Yes, the control part 10 advances a process to step S210.
In No, the control part 10 advances a process to step S211.

(Step S210)
When it is a timer return, the control part 10 performs a return time end numerical value correction process by the elapsed time calculation part 110.
Referring to FIG. 8 again, the control unit 10 acquires the return time fraction value 540 stored in the storage unit 19 and adds it to the clock count value 510. Thereby, when the timer is restored, the clock count value 510 can be corrected with higher accuracy than the time of the minimum value of the time value 520 that can be acquired from the real-time clock unit 20.

(Step S211)
Here, the control unit 10 performs clock count processing by the elapsed time calculation unit 110. The control unit 10 counts the clock during the normal activation state, and increases the clock count value 510.

(Step S212)
Next, the control unit 10 causes the elapsed time calculation unit 110 to determine whether or not the clock count of the waiting process has ended. When the clock count value 510 reaches the waiting time specified by the control program, the control unit 10 determines Yes because the waiting time has elapsed. In other cases, the control unit 10 determines No because the waiting time has not yet elapsed.
In the case of Yes, the control unit 10 stops counting the clock and ends the waiting process.
In No, the control part 10 returns a process to step S203, and continues the count of a clock.
Thus, the waiting process according to the embodiment of the present invention is completed.

With the configuration described above, the following effects can be obtained.
Conventionally, in order to realize low power consumption in the sleep state, when the power source of the control unit is turned off, there has been a shift in the elapsed time in the waiting process. However, in the technique of Patent Document 1, a special circuit such as a CR oscillation circuit or a crystal oscillation circuit is required to correct this elapsed time. When the power supply of the circuit itself is turned off, the deviation can be corrected. could not.
In contrast, the image forming apparatus 1 according to the embodiment of the present invention includes a control unit 10 and a real-time clock unit 20 that measures time even when the control unit 10 enters a power saving state. In the normal activation state, the reference time value acquisition unit 100 that acquires the time value 520 of the real-time clock unit 20 as the reference time value 550 and the clock count value 510 of the control unit 10 after the control unit 10 is in the power saving state When the waiting process for measuring time is being performed, the waiting process is performed based on the reference time value 550 acquired by the reference time value acquiring unit 100 and the time value 520 of the real-time clock unit 20 when returning from the power saving state. An elapsed time calculation unit 110 that calculates the elapsed time is provided.
With such a configuration, the image forming apparatus 1 is accurate even when the power supply to the circuit that generates the clock is stopped when returning from the power saving state to the normal activation state during the waiting process. Time correction is possible.
In addition, the real-time clock is generally a device that is often mounted, and an external timer or a special circuit described in Patent Document 1 is not necessary. This can reduce costs.

Conventionally, in network communication, when a timeout process is performed or when it is necessary to operate in a time determined by a protocol, the elapsed time of the waiting process counted by the control means and the actual time are calculated. It was necessary to match as much as possible.
However, for example, as shown in FIG. 9, in the configuration in which the time value of the real-time clock is directly acquired and corrected when shifting to the power saving state and when returning, the difference in the elapsed time of the waiting process is recovered. Every time you do it, it will increase. In particular, in network communication, it is conceivable to return from a power-saving state in detail, so that the deviation gradually increases and may be several seconds or longer.
On the other hand, as shown in FIG. 7, the image forming apparatus 1 according to the present embodiment always corrects the clock count value 510 with the reference time value 550, and thus shifts to the power saving state a plurality of times from the start of the waiting process. Even if recovery is performed, the deviation is within the minimum value of the real-time clock time. For this reason, it is possible to suppress a difference in elapsed time of the waiting process and to prevent a network communication error or the like.

Further, in the image forming apparatus 1 according to the embodiment of the present invention, the reference time value acquisition unit 100 rounds up or rounds down the fraction of the reference time value 550 that is less than 1 second by the clock count value 510 of the control unit 10. It is characterized by.
With this configuration, the difference in elapsed time of the waiting process can be made smaller than the minimum value of the time of the real-time clock, and the elapsed time of the waiting process can be accurately corrected.

Further, the image forming apparatus 1 according to the embodiment of the present invention includes a power saving return timer unit 30 that returns the control unit 10 from the power saving state according to the set return time 530, and the reference time value acquisition unit 100 includes: When the return time 530 is set in the power saving return timer unit 30, the return time fraction value 540 is acquired from the clock count value 510 of the control unit 10, and the elapsed time calculation unit 110 saves power at the set return time 530. When returning from the power saving state by the return timer unit 30, the calculated elapsed time of the waiting process is corrected by the return time fraction value 540.
With this configuration, the timer return by the power saving return timer unit 30 can eliminate almost all of the elapsed time of the waiting process. For this reason, errors can be prevented even in a waiting process whose timing is important, such as network communication, document reading by the document reading unit 12, and image formation by the image forming unit 17. For this reason, it is possible to easily shift to a low power consumption state such as a sleep state, and as a result, it is possible to reduce power consumption.

[Other Embodiments]
In the embodiment of the present invention, the time of the power saving return timer unit 30 is described so as to be interlocked with the real time clock unit 20, but the present invention is not limited to this. That is, the power saving return timer unit 30 may include a timer using a unique CR oscillation circuit, a crystal oscillation circuit, or the like, and be able to return to the set return time 530.
In this case, the return time fraction value 540 is set correspondingly when the return time 530 is set. For example, the control unit 10 uses the clock value 510 when the return time 530 is set in the time value 520 of the real-time clock unit 20 as the return time fraction value 540 and corrects it.
With this configuration, even when an external timer that is not linked to the real time clock is used, the elapsed time of the waiting process can be accurately measured.

Further, the control unit 10 may reduce the error of the reference time value 550 by a method other than simply rounding up or rounding off the fraction of the reference time value 550 less than 1. For example, the control unit 10 may add or subtract a random value to the clock count value 510 when returning from the low power consumption state to the normal activation state.
With this configuration, the error is reduced by the central limit theorem when the transition to the power saving state and the normal activation state is repeated many times by an interval timer or the like. As a result, the waiting time error can be reduced.

The real-time clock unit 20 may be outside the image forming apparatus 1. In this case, the control unit 10 may acquire the time value 520 from an external time server (not shown) via the network transmission / reception unit 15 using a protocol such as NTP. In this case, the calculation of the elapsed time is corrected by adding an error such as a network delay.
This makes it possible to accurately measure the elapsed time of the waiting process even in a configuration without a real-time clock.

Further, the control unit 10 may be completely turned off in the power saving state, not in the sleep state. In this case, the clock count value 510 may be temporarily stored in the storage unit 19 when shifting to the power saving state. In this case, the return signal is transmitted to a power supply control unit (not shown), and this power supply control unit activates the control unit 10.
If comprised in this way, even if the power supply of the control part 10 is completely turned off, the elapsed time of a waiting process can be measured correctly.

The control unit 10 may calculate each time in consideration of a predetermined delay value until the time value 520 of the real-time clock unit 20 can be acquired after the power saving state is restored.
This makes it possible to measure the elapsed time of the waiting process more accurately.

Further, in addition to the normal startup state, the control unit 10 can be configured to shift each unit to a “low power state” in which power consumption is greater than that in the sleep state, but recovery is quick and background treatment can be performed. .
In the case of returning from such a low power state, in addition to adjusting the predetermined delay value described above, the acquisition timing of the acquired time value 520 can be delayed.
This makes it possible to accurately measure the elapsed time of the waiting process using the real-time clock when returning from the low power state and returning from the sleep state.

In the above-described embodiment, the control unit 10 is described to start counting the clock count value 510 at the start of the waiting process, but the present invention is not limited to this. That is, the control unit 10 may be configured to always count the clock as “system time” and hold it in a register or the like. Also in this case, by calculating a difference or the like of the clock count value 510, it is possible to perform the same processing as that in the above-described embodiment and accurately measure the elapsed time. In addition, the count start timing of the clock count value 510 may be when the reference time value 550 is acquired. Thereby, the reference time value 550 and the clock count value 510 can be accurately linked. Further, the count may be started at other timing.
Further, the time value 520 of the real-time clock unit 20 may be acquired not in units of 1 second but in units of 1/100 seconds, for example. This makes it possible to accurately measure the waiting time.

  The present invention can also be applied to an information processing apparatus other than the image forming apparatus. That is, a configuration using a network scanner, a server in which the scanner is separately connected via USB, or the like may be used.

  Further, the configuration and operation of the above-described embodiment are examples, and it goes without saying that they can be appropriately modified and executed without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 10 Control part 11 Image processing part 12 Original reading part 12a Scanner 12b Platen glass 12c Original reading slit 13 Original feeding part 13a Original placing part 13b Original discharge part 13c Original conveyance mechanism 14 Main body part 15 Network transmission / reception part 16 Operation panel section 17 Image forming section 17a Photosensitive drum 17b Exposure section 17c Development section 17d Transfer section 17e Fixing section 19 Storage section 20 Real-time clock section 30 Power saving return timer section 41 Discharge port 42 Paper feed section 43 Paper transport path 44 Transport roller 45 Discharge roller 50 Stack tray 100 Reference time value acquisition unit 110 Elapsed time calculation unit 421 Paper feed cassette 422 Paper feed roller 510 Clock count value 520 Time value 530 Return time 540 Return time fraction value 550 Reference time value 560 Start time value

Claims (2)

Image formation comprising a control unit that counts a clock in a normal startup state and holds it as a clock count value, a real-time clock unit that measures time and holds it as a time value even when the control unit enters a power saving state, and a storage unit In the device
A return time value is stored, and in conjunction with the time value of the real-time clock unit, when the return time value is reached, a power saving return timer unit that returns the control unit from the power saving state;
A reference time value acquisition unit that acquires a time value of the real-time clock unit as a reference time value in the normal startup state of the control unit;
When the control unit has been performing a waiting process for measuring elapsed time based on the clock count value of the control unit before the power saving state, the reference time value acquired by the reference time value acquisition unit, An elapsed time calculation unit that calculates an elapsed time of the waiting process according to the time value of the real-time clock unit when returning from the power state,
The control unit acquires a clock count value until the time value of the real-time clock unit changes by 1 second after acquiring the reference time value by the reference time value acquisition unit, and calculates the value of the acquired clock count value. , Converted to a value in seconds including a value after the decimal point, and subtracts the converted value from 1 to calculate a fraction of less than 1 in seconds until the reference time value is obtained. If it is less than 0.5 seconds, round down the fraction and store the reference time value acquired in the storage unit as it is.If this fraction is 0.5 seconds or more, round up the fraction, Increase the reference time value by 1,
When starting the waiting process, the control unit,
(1) Obtaining a time value of the real-time clock unit and storing it in the storage unit as a start time value;
(2) The elapsed time calculation unit determines whether to shift to the power saving state, determines whether it is necessary to perform a timer return when shifting to the power saving state, When it is necessary to perform a timer return, set the return time value in the power saving return timer unit,
(3) When the return time value is set, the clock count value when the time value of the real-time clock unit is changed is subtracted from the clock count value when the state is shifted to the power saving state. Calculate the time fraction value and store it in the storage unit, perform the transition to the power saving state,
(4) when starting returning from the power saving state to the normal activation state, and the time value of the real time clock unit acquired at the time of return, the waiting by comparing the start time value stored in the storage unit Calculate the elapsed time from the start of processing, add the calculated elapsed time to the clock count value,
(5) The elapsed time calculation unit determines whether or not the timer has been restored. If the timer has been restored, the return time fraction value stored in the storage unit is acquired, and the start of the waiting process. An image forming apparatus , wherein the elapsed time is added to a clock count value to which the elapsed time is added . Image formation comprising a control unit that counts a clock in a normal startup state and holds it as a clock count value, a real-time clock unit that measures time and holds it as a time value even when the control unit enters a power saving state, and a storage unit In an image forming method by an apparatus,
The image forming apparatus further includes:
A return time value is stored, and in conjunction with the time value of the real-time clock unit, when the return time value is reached, a power saving return timer unit that returns the control unit from the power saving state;
A reference time value acquisition unit that acquires a time value of the real-time clock unit as a reference time value in the normal startup state of the control unit;
When the control unit has been performing a waiting process for measuring elapsed time based on the clock count value of the control unit before the power saving state, the reference time value acquired by the reference time value acquisition unit, An elapsed time calculation unit that calculates an elapsed time of the waiting process according to a time value of the real-time clock unit at the time of return from the power state,
By the control unit,
After acquiring the reference time value by the reference time value acquisition unit, acquire a clock count value until the time value of the real-time clock unit changes by 1 second, and set the acquired clock count value to a value after the decimal point. Is converted to a value in seconds containing, and the converted value is subtracted from 1.
Calculates a fraction of less than 1 in seconds until the reference time value is acquired, and if this fraction is less than 0.5 seconds, rounds down the reference time value acquired in the storage unit Is stored as it is, and when this fraction is 0.5 seconds or more, the fraction is rounded up and the reference time value is increased by 1,
When starting the waiting process, the control unit
(1) Obtaining a time value of the real-time clock unit and storing it in the storage unit as a start time value;
(2) The elapsed time calculation unit determines whether to shift to the power saving state, determines whether it is necessary to perform a timer return when shifting to the power saving state, When it is necessary to perform a timer return, set the return time value in the power saving return timer unit,
(3) When the return time value is set, the clock count value when the time value of the real-time clock unit is changed is subtracted from the clock count value when the state is shifted to the power saving state. Calculate the time fraction value and store it in the storage unit, perform the transition to the power saving state,
(4) when starting returning from the power saving state to the normal activation state, and the time value of the real time clock unit acquired at the time of return, the waiting by comparing the start time value stored in the storage unit Calculate the elapsed time from the start of processing, add the calculated elapsed time to the clock count value,
(5) The elapsed time calculation unit determines whether or not the timer has been restored. If the timer has been restored, the return time fraction value stored in the storage unit is acquired, and the start of the waiting process. An image forming method comprising: adding to an added clock count value.

Images