JP2014197065A - Image forming apparatus and time measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus that can be operated in a low-speed mode with a built-in clock.SOLUTION: A low-speed mode processing unit 81 for a low-speed mode controls respective units in a power-saving low-speed mode with a built-in clock having a large periodic error. A temperature sensor 13 detects a temperature of the low-speed mode processing unit 81. The low-speed mode processing unit 81 measures in advance an error of the built-in clock with an external high-precision clock, and stores a result of the measurement in a storage unit 9. With the completion of the above operation, the low-speed mode processing unit 81 corrects, at the start-up of an image forming apparatus, the built-in clock on the basis of the temperature detected by the temperature sensor 13 and the error of the built-in clock stored in the storage unit 9.

Description

  The present invention relates to an image forming apparatus and a time measuring apparatus, and more particularly, to an image forming apparatus and a time measuring apparatus for controlling a high speed mode and a low speed mode.

Conventionally, in image forming apparatuses such as copiers and multifunction peripherals (Multifunctional Peripherals, MFPs), the CPU and other control means are divided into “high-speed mode” and “low-speed mode”, which are operation modes with different clock frequencies. May cause processing.
The “high-speed mode” is an operation mode in which each unit that consumes a large amount of power is controlled at a normal or high clock frequency during normal operation. The “low-speed mode” is an operation mode in which each unit driven with low power consumption is controlled at a clock frequency lower than that in the high-speed mode during standby or the like.
With reference to Patent Document 1, an image forming apparatus using such different operation modes is described.

JP 2009-265374 A

In a conventional image forming apparatus such as Patent Document 1, high-precision clock generation means such as a dedicated crystal resonator is often used in the high-speed mode and the low-speed mode.
However, the high-accuracy clock generation means is expensive, and there has been a demand for utilizing a built-in clock by an on-chip oscillator for the low-speed mode.
On the other hand, the built-in clock has a large cycle error of several tens of percent and has a low accuracy, so it cannot be used as it is.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus capable of operating in a low-speed mode with a built-in clock.

An image forming apparatus according to the present invention, in an image forming apparatus including an image forming unit that forms an image on a sheet, receives a high-precision clock generating unit that generates a high-precision clock, and the high-precision clock generated by the high-precision clock generating unit. A high-speed mode control unit that controls each unit including the image forming unit, a low-speed mode control unit that includes a built-in clock generation unit that generates a built-in clock slower than the high-precision clock, and an error value of the built-in clock. Error storage means for storing the temperature, temperature detection means for detecting the temperature of the low-speed mode control means, temperature detected by the temperature detection means, and error value of the built-in clock stored in the error storage means On the basis of the built-in clock correction means for correcting the error of the built-in clock, and the low-speed mode control means includes the built-in clock. And controlling each unit by using the internal clock that is corrected by positive means.
In the image forming apparatus of the present invention, the built-in clock error measuring unit changes the temperature of the built-in clock error measuring unit that measures the error of the built-in clock with the high-precision clock, and the built-in clock error measuring unit changes the temperature of the built-in clock error measuring unit. A correction value table for measuring a clock error and correcting a deviation for each temperature is prepared, and stored in the error storage means. The built-in clock correction means is created by the calibration means. The internal clock of the low-speed mode control means is corrected by the correction value table.
The time measuring device of the present invention includes a high-accuracy clock generation unit that generates a high-accuracy clock, a high-speed mode control unit that receives the high-accuracy clock of the high-accuracy clock generation unit and controls each unit, and the high-accuracy clock Low-speed mode control means having built-in clock generation means for generating a built-in clock slower than the clock, error storage means for storing the error value of the built-in clock, and temperature detection means for detecting the temperature of the low-speed mode control means An internal clock correction unit that corrects an error of the internal clock based on the temperature detected by the temperature detection unit and an error value of the internal clock stored in the error storage unit, and the low-speed mode The control means controls each part using the internal clock corrected by the internal clock correction means.

  According to the present invention, the low-speed mode control unit corrects the internal clock based on the temperature detected by the temperature detection unit and the inherent error value of the internal clock stored in the error storage unit in advance. An image forming apparatus that can operate with a built-in clock during the mode can be provided.

1 is a schematic cross-sectional view showing an internal configuration of a first embodiment of an image forming apparatus according to the present invention. 1 is a block diagram showing a control configuration of a first embodiment of an image forming apparatus according to the present invention. 3 is a flowchart of internal clock correction and low-speed mode execution processing in the first embodiment of the image forming apparatus according to the present invention. FIG. 3 is a conceptual diagram of a correction value table shown in FIG. 2. 6 is a flowchart of calibration processing according to a second embodiment of the image forming apparatus according to the present invention.

<First Embodiment>
[Configuration of Image Forming Apparatus 1]
First, the configuration of the image forming apparatus 1 (time measuring device) according to the first embodiment will be described with reference to FIGS.
The image forming apparatus 1 according to the present embodiment includes a document reading unit 2, a document feeding unit 3, a main body unit 4, a stack tray 5, and an operation panel unit 6.
The document reading unit 2 is disposed on the top of the main body unit 4, and the document feeding unit 3 is disposed on the top of the document reading unit 2. The stack tray 5 is disposed on the recording paper discharge port 41 side on which the main body unit 4 is formed, and the operation panel unit 6 is disposed on the front side of the image forming apparatus 1.

  The document reading unit 2 includes a scanner 21, a platen glass 22, and a document reading slit 23. The scanner 21 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 3. The platen glass 22 is an original table made of a transparent member such as glass. The document reading slit 23 has a slit formed in a direction orthogonal to the document transport direction by the document feeder 3.

When reading a document placed on the platen glass 22, the scanner 21 is moved to a position facing the platen glass 22 and reads the document while scanning the document placed on the platen glass 22 to obtain image data. The acquired image data is output to the main unit 4.
When reading the document conveyed by the document feeding unit 3, the scanner 21 is moved to a position facing the document reading slit 23, and the document is conveyed by the document feeding unit 3 through the document reading slit 23. 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 4.

  The document feeding unit 3 includes a document placement unit 31, a document discharge unit 32, and a document transport mechanism 33. The originals placed on the original placement unit 31 are sequentially fed out one by one by the original conveyance mechanism 33, conveyed to a position facing the original reading slit 23, and then discharged to the original discharge unit 32. The document feeding unit 3 is configured to be retractable, and the upper surface of the platen glass 22 can be opened by lifting the document feeding unit 3 upward.

The main body unit 4 includes the image forming unit 7, 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 conveyance path 43 by the paper supply roller 422 is conveyed to the image forming unit 7 by the conveyance roller 44.
The recording paper on which recording has been performed by the image forming unit 7 is discharged to the stack tray 5 by the discharge roller 45.

The operation panel unit 6 includes a display unit such as a liquid crystal display or an organic EL display, a button including a numeric keypad, and the like.
The operation panel unit 6 detects an instruction from the user and transmits it to the control unit 8. The operation panel unit 6 can also acquire the control settings for the high speed mode and the low speed mode.

The image forming unit 7 includes a photosensitive drum 71, an exposure unit 72, a developing unit 73, a transfer unit 74, and a fixing unit 75. The exposure unit 72 is an optical unit including a laser device, an LED array, a mirror, a lens, and the like. The exposure unit 72 outputs light or the like based on image data to expose the photosensitive drum 71, and the surface of the photosensitive drum 71 is statically exposed. An electrostatic latent image is formed.
The developing unit 73 is a developing unit that develops the electrostatic latent image formed on the photosensitive drum 71 using toner, and forms a toner image based on the electrostatic latent image on the photosensitive drum 71. The transfer unit 74 transfers the toner image formed on the photosensitive drum 71 by the developing unit 73 to a sheet. The fixing unit 75 performs recording by heating the sheet on which the toner image is transferred by the transfer unit 74 and fixing the toner image on the sheet.

FIG. 2 is a block diagram illustrating a schematic configuration of the image forming apparatus 1.
The document reading unit 2, document feeding unit 3, transport unit (feed roller 422, transport roller 44, discharge roller 45), operation panel unit 6, and image forming unit 7 include a control unit 8 (high-speed mode control means). , Low-speed mode control means), and the operation of the controller 8 is controlled.
Further, the control unit 8 includes a storage unit 9 (storage unit, error storage unit), an image processing unit 10 (image processing unit), a FAX transmission / reception unit 11, a network transmission / reception unit 12, a temperature sensor 13 (temperature detection unit), and A high-speed clock unit 14 (external clock, high-precision clock generation means) is connected.

The control unit 8 is information processing means such as a general-purpose CPU, a microcomputer, a microcontroller (microcomputer) provided with a ROM (Read Only Memory), a RAM (Random Access Memory) and the like. A control program for controlling the operation of the image forming apparatus 1 is stored in the ROM of the control unit 8.
The control unit 8 and the image processing unit 10 read out a control program stored in the ROM and develop the control program in the RAM, thereby controlling the entire apparatus according to predetermined instruction information input from the operation panel unit 6. I do.

In a normal operation state, the control unit 8 performs control in the “high-speed mode” in which each process is executed at a high-speed clock frequency. In the “high-speed mode”, the control unit 8 executes each of the power-consuming units including the image forming unit 7 in synchronization with the high-precision clock of the high-speed clock unit 14.
The control unit 8 can also perform control in a “low speed mode” in which each process is executed with a low speed internal clock. In the “low speed mode”, for example, each process with low power consumption, such as reception of a facsimile or a scanner, transmission / reception of a packet in the network transmission / reception unit 12, is executed in a low power consumption state such as a standby state. The processing in the “low speed mode” is mainly performed by the low speed mode processing unit 81 described below.

The low-speed mode processing unit 81 (low-speed mode control means, built-in clock error measurement means, built-in clock correction means, calibration means) mainly executes processing in the “low-speed mode” with low power consumption.
The low-speed mode processing unit 81 operates by generating a built-in clock having a frequency lower than that of the high-speed clock unit 14, for example, a clock in KHz or MHz, by built-in clock generation means such as a built-in on-chip oscillator. The built-in clock generated by the built-in clock generation means is less accurate than the high-precision clock, has an error for each substrate, and varies with voltage, temperature, and the like.
The low-speed mode processing unit 81 operates at a predetermined operation frequency lower than that in the “high-speed mode” in the “low-speed mode”, and therefore, strict operation clock accuracy is not required. However, since the low-speed mode processing unit 81 performs processing that requires synchronization such as I / O control and network transmission / reception by the network transmission / reception unit 12, the low-speed mode processing unit 81 adjusts the clock cycle so that the clock accuracy is within a predetermined value. It is necessary to correct the error.

The storage unit 9 is a storage unit such as a semiconductor memory or an HDD (Hard Disk Drive). The storage unit 9 stores various programs and data. Among these, the semiconductor memory of the storage unit 9 includes a nonvolatile memory such as a RAM, an EEPROM, a NAND type, or a NOR type flash memory.
The storage unit 9 stores job data for executing various jobs. The job data is image data acquired by reading a document by the document reading unit 2, print document data transmitted from a PC (not shown), various files such as FAX reception data, and the like.

  The image processing unit 10 is a control calculation part of a DSP (Digital Signal Processor) or a GPU (Graphics Processing Unit). The image processing unit 10 is a unit that performs predetermined image processing on image data, and performs, for example, image improvement processing such as enlargement / reduction processing, density adjustment, and gradation adjustment.

The FAX transmission / reception unit 11 is a means for performing facsimile transmission / reception, and is connected to a normal telephone line, ISDN line, or the like. Further, the FAX transmission / reception unit 11 stores the received facsimile image in the storage unit 9.
Further, the FAX transmission / reception unit 11 can transmit the image data stored in the storage unit 9 by facsimile instead of printing by the image forming unit 7.

The network transmission / reception unit 12 is a network connection means including a LAN board, a wireless transmission / reception unit, a telephone dialer, a coupler, and the like for connecting to a network.
The network transmission / reception unit 12 transmits / receives data on a data communication line and transmits / receives audio signals on a voice telephone line.

The temperature sensor 13 is a temperature sensor including a thermistor, an infrared sensor, an A / D converter, and the like.
The temperature sensor 13 is provided in the package of the control unit 8 or just outside, and measures the temperature near the low speed mode processing unit 81 in the low speed mode. This configuration is preferable because the temperature of the low-speed mode processing unit 81 can be measured more directly.
Further, the temperature sensor 13 may be provided in another part of the image forming apparatus 1. For example, the temperature sensor 13 can also measure the temperature inside or outside the casing of the image forming apparatus 1. In this case, the temperature sensor 13 is mainly arranged on a substrate other than the portion where the high temperature is generated, such as the image forming unit 7, and is a so-called ambient temperature in the casing, which is an average temperature inside the image forming apparatus 1, or Measure the external environment temperature outside the enclosure.

The high-speed clock unit 14 is a high-accuracy clock generation circuit that has high accuracy (small error in the period), for example, using a crystal resonator. The high-speed clock unit 14 supplies an accurate high-accuracy clock (operation clock) to the control unit 8.
The high-precision clock of the high-speed clock unit 14 serves as a reference when correcting the clock error of the low-speed mode processing unit 81.

Note that the low-speed mode processing unit 81 may be a CPU different from the control unit 8, and may use a low power consumption core of a multi-core CPU.
Further, the low speed mode processing unit 81 may incorporate the temperature sensor 13.
In addition, the control unit 8, the storage unit 9, and the image processing unit 10 may be integrally formed, such as a memory built-in CPU, a GPU built-in CPU, a chip-on-module package, and the like.

(Configuration of storage unit 9)
The nonvolatile memory of the storage unit 9 stores a substrate error 91 and a correction value table 92 that are data for correcting an error of the built-in clock.
The board error 91 is data indicating an error value of a built-in clock specific to each board of the low-speed mode processing unit 81. The substrate error 91 may be calculated in advance by the low speed mode processing unit 81 at the time of factory shipment or the like and stored in the storage unit 9.
The correction value table 92 is data of a table for correcting a deviation for each temperature. The correction value table 92 may include a plurality of error values indicating the relationship between the temperature of the low-speed mode processing unit 81 and the error of the built-in clock.
Note that the storage unit 9 may also store settings for switching between the high speed mode and the low speed mode, a table for correcting the operation clock of the low speed mode processing unit 81 by voltage, and the like.

[Built-in clock correction and low-speed mode execution processing by the image forming apparatus 1]
Next, the built-in clock correction and low-speed mode execution processing of the low-speed mode processing unit 81 according to the first embodiment of the present invention will be described in detail with reference to FIG.
The built-in clock correction and low-speed mode execution processing of the low-speed mode processing unit 81 is mainly based on various settings stored in the storage unit 9, and the program stored in the ROM of the low-speed mode processing unit 81 is used as the low-speed mode processing unit 81. Can be realized by using hardware resources.

(Step S101)
When an instruction to change to the low speed mode is given, first, the low speed mode processing unit 81 performs start-up and correction start processing.
When the image forming apparatus 1 transitions to the power saving state, the control unit 8 instructs the change to the low speed mode.
Then, a reset signal is input, and the low-speed mode processing unit 81 is activated with the built-in clock.
At this time, the low-speed mode processing unit 81 executes a program stored in the ROM, performs various initialization processes, and starts clock correction.

(Step S102)
After the initialization is completed, the low speed mode processing unit 81 performs a temperature acquisition process.
The low speed mode processing unit 81 detects the temperature with the temperature sensor 13. This temperature corresponds to the temperature of the low-speed mode processing unit 81 itself at the time of detection.

(Step S103)
Next, the low speed mode processing unit 81 performs a correction value acquisition process.
Referring to FIG. 4, in the correction value table 92, for example, an error value indicating a difference value between the built-in clock and the standard clock S is stored as a curve D. That is, the curve D is, for example, a set of error values corresponding to the temperature in a predetermined section corresponding to the allowable operating temperature range of the low speed mode processing unit 81.
The low speed mode processing unit 81 reads the error value of the built-in clock corresponding to the temperature detected by the temperature sensor 13 from the correction value table 92 of the storage unit 9.
In addition, the low-speed mode processing unit 81 reads an error value for each substrate from the substrate error 91.

(Step S104)
Next, the low speed mode processing unit 81 performs clock correction processing.
The low speed mode processing unit 81 performs clock correction for changing the frequency of the built-in clock based on the read error value.
The low-speed mode processing unit 81 calculates a correction value of the frequency of the built-in clock based on the error value of the correction value table 92 corresponding to the temperature acquired from the temperature sensor 13 and the error value for each substrate of the substrate error 91. .
For example, when the error value of the correction value table 92 corresponding to the temperature is + 3% and the error value for each substrate of the substrate error 91 is + 1%,

Correction value = (+ 3%) + (+ 1%) = + 4%

And calculate. Then, the low-speed mode processing unit 81 changes the frequency of the built-in clock based on this correction value. In this example, the frequency of the built-in clock is changed by 4% from the standard value. For example, the low-speed mode processing unit 81 can change the frequency of about + −10% of the reference value of the built-in clock.
Thereby, the correction of the internal clock of the low-speed mode processing unit 81 is completed. By the correction, it is possible to perform processing by means of which accuracy in the timing and counting is important, such as network transmission / reception and facsimile transmission / reception, while maintaining the accuracy of the internal clock of the low-speed mode processing unit 81.

(Step S105)
Thereafter, the low-speed mode processing unit 81 performs a low-speed mode execution process that is each process in the low-speed mode.
In each processing in the low-speed mode, for example, power is not supplied to each of the high power consumption units including the high-speed clock unit 14 and the image forming unit 7 or the power consumption state is set. In addition, the low-speed mode processing unit 81 performs reception processing, transmission processing, and the like of the FAX transmission / reception unit 11 and the network transmission / reception unit 12 and stores the reception data in the storage unit 9.
Thus, the built-in clock correction and the low-speed mode execution process of the low-speed mode processing unit 81 are completed.
Note that the low-speed mode processing unit 81 may correct the internal clock again when the temperature detected by the temperature sensor 13 has changed. The correction of the built-in clock may be performed in real time (real time).

With the configuration described above, the following effects can be obtained.
The image forming apparatus 1 according to the first exemplary embodiment of the present invention includes a high-speed clock unit 14 that generates a high-accuracy clock with a small period error in an image forming apparatus including an image forming unit 7 that forms an image on a recording sheet. And the control unit 8 that receives the high-precision clock generated by the high-speed clock unit 14 and controls each unit including the image forming unit 7 in the high-speed mode with high power consumption, and the cycle error is higher than that of the high-speed clock unit 14. A temperature detected by the temperature sensor 13 includes a low-speed mode processing unit 81 that controls each unit in a power-saving low-speed mode and a temperature sensor 13 that detects the temperature of the low-speed mode processing unit 81 with a large and low-speed internal clock. And the built-in clock of the low-speed mode processing unit 81 is corrected based on the error value of the substrate error 91 stored in the storage unit 9.
As a result, by correcting the error on the substrate and the internal clock of the low-speed mode processing unit 81 with low accuracy by the temperature sensor 13, it is possible to correct the clock and obtain the time reference by the CPU internal clock. Therefore, it is not necessary to separately provide a crystal resonator for the low-speed mode processing unit 81, and it is possible to provide the image forming apparatus 1 that is less expensive than the conventional one.

Conventionally, as a means for correcting the built-in clock with low accuracy of the low-speed mode control unit, a method of correcting with a high-speed mode crystal resonator is generally used.
However, it is not realistic to adjust the internal clock using the high-speed clock every time when starting the control unit for the low-speed mode, because power consumption increases until the transition to low power consumption. .
In addition, the correction method using a high-speed clock with good accuracy is affected by temperature fluctuations. For this reason, even if the error value of the substrate error is simply stored and read out, it cannot be used when switching to the low-speed mode with low power consumption.
On the other hand, the image forming apparatus 1 according to the present embodiment stores an error value of a built-in clock specific to each board as a board error 91 in the nonvolatile memory of the storage unit 9, and reads this at startup. Also adjust the effect of temperature fluctuations. As a result, it is possible to avoid the trouble of performing the clock correction again, and to use the internal clock in the low speed mode. In addition, it is possible to quickly shift to the low-speed mode, and the effect that power consumption can be suppressed can be obtained.

The low-speed mode processing unit 81 can also correct the clock error value based on, for example, the ambient temperature inside the image forming apparatus 1 or the external environment temperature. In this case, the low speed mode processing unit 81 detects the temperature with the temperature sensor 13. On this basis, the low-speed mode processing unit 81 may calculate a correction value for the frequency of the internal clock including the ambient temperature and the external environment temperature.
Further, the low-speed mode processing unit 81 can also correct the clock error value by voltage, for example. In this case, the low-speed mode processing unit 81 detects the power supply voltage, reads an error value based on the detected power supply voltage from the storage unit 9, and based on the substrate error 91 and the correction value table 92, the built-in clock. The frequency correction value may be calculated.

<Second Embodiment>
Next, a second embodiment of the present invention will be described with reference to FIG.
In the second embodiment of the present invention, the low-speed mode processing unit 81 uses the hardware having the same configuration as that of the image forming apparatus 1 (FIG. 2) according to the first embodiment, and the substrate error 91 is detected. Calibration processing for creating a correction value table 92 for a predetermined temperature section is performed.
The low-speed mode processing unit 81 performs this calibration processing when the power is turned on for the first time, when a predetermined period of about several months to once a year has passed, or when instructed by the user. .
Details of the calibration processing will be described below with reference to the flowchart of FIG.

(Step S111)
First, the low-speed mode processing unit 81 detects the temperature of the low-speed mode processing unit 81 with the temperature sensor 13 as in the temperature acquisition processing (FIG. 3) in step S102 of the first embodiment.

(Step S112)
Next, the low speed mode processing unit 81 performs a correction value calculation process.
Referring to FIG. 4 again, the low-speed mode processing unit 81 measures the frequency of the built-in clock at that temperature by activating the high-speed clock unit 14.
Then, the low speed mode processing unit 81 calculates a difference value between the measured clock and the standard clock S. At this time, the low speed mode processing unit 81 uses the temperature acquired by the temperature sensor 13 to calculate a difference value at that temperature. Then, the low-speed mode processing unit 81 further subtracts a substrate error 91, which is a specific error value for each substrate measured at the time of factory shipment, from the calculated difference value at that temperature. The low-speed mode processing unit 81 writes a value obtained by subtracting the substrate error 91 from the difference value at that temperature in a location corresponding to the detected temperature in the correction value table 92.

(Step S113)
Next, the low speed mode processing unit 81 performs a temperature increase process.
The low speed mode processing unit 81 executes a program that applies a processing load such as a predetermined benchmark program stored in the ROM, and raises the temperature of the low speed mode processing unit 81 itself.
A heater for the low-speed mode processing unit 81 or a heater for each unit of the image forming apparatus 1 may be provided separately. Then, the temperature of the low-speed mode processing unit 81 may be increased by heat generated by the heater or the like.

(Step S114)
First, the low speed mode processing unit 81 determines whether or not a correction value for a predetermined section has been calculated. The low-speed mode processing unit 81 determines Yes when the correction value table 92 has been calculated as a sufficient difference value for a predetermined temperature section. The low speed mode processing unit 81 determines No when the difference value of the predetermined temperature section has not yet been calculated.
In the case of Yes, the low speed mode processing unit 81 ends the calibration process.
In No, the low speed mode process part 81 returns a process to step S111, and performs temperature acquisition and correction value calculation in the raised temperature.

As described above, the low-speed mode processing unit 81 calculates the difference value between the temperature detected by the temperature sensor 13 and the clock of the high-speed clock unit 14 while increasing the temperature, and the internal clock measured at the time of factory shipment is calculated. Substrate error 91 is further subtracted and written in correction value table 92. As a result, a correction value table 92 indicating the relationship between the temperature and the error value is created as shown by a curve D in FIG.
After calibration, the control unit 8 causes the low-speed mode processing unit 81 to shift to a pause state and sufficiently cool it.
The low-speed mode processing unit 81 can correct the internal clock using the substrate error 91 and the calibrated correction value table 92 at the time of transition to the low-speed mode, as in the first embodiment. Is possible.

With the configuration described above, the following effects can be obtained.
In the second embodiment of the present invention, the low-speed mode processing unit 81 measures the error of the internal clock of the low-speed mode processing unit 81 using the high-precision clock of the high-speed clock unit 14, and determines the temperature of the low-speed mode processing unit 81. The correction value table 92 for measuring the error of the built-in clock and changing the deviation for each temperature is generated and stored in the storage unit 9, and the low-speed mode processing unit 81 generates the correction value table 92, the internal clock of the low-speed mode processing unit 81 is corrected.
Thereby, at the time of shifting to the low speed mode, it is possible to read the correction value table 92 in which the error of each substrate and the influence of the temperature fluctuation are recorded, and to quickly correct the internal clock of the low speed mode processing unit 81. In addition, it is possible to accurately adjust the clock of the low-speed mode processing unit 81 by accurately calculating the error of the built-in clock due to temperature.

  In addition, the time measuring device according to the first or second embodiment of the present invention includes a high-speed clock unit 14 that generates a high-precision clock with a small period error, and a high-precision clock generated by the high-speed clock unit 14. The low-speed mode that controls each part in the power-saving low-speed mode by the control part 8 that receives and controls each part in the high-speed mode with high power consumption and the built-in clock that has a larger period error than the high-speed clock part 14 and that is low-speed The low-speed mode processing unit 81 includes a processing unit 81 and a temperature sensor 13 that detects the temperature of the low-speed mode processing unit 81, and the low-speed mode processing unit 81 uses an accurate clock of the high-speed clock unit 14 to detect an error in the internal clock of the low-speed mode processing unit 81. The internal clock error measured by the low-speed mode processing unit 81 is stored in the storage unit 9, the temperature detected by the temperature sensor 13, and the storage unit 9 Based on the errors of 憶 been built clock, and corrects the internal clock of the low-speed mode processing unit 81.

In the second embodiment of the present invention, the low-speed mode processing unit 81 does not calculate the temperature and the error value one by one, but calculates several error values for the predetermined temperature to create a complementary curve, etc., and the correction value table 92 may be written.
The low-speed mode processing unit 81 may write a value obtained by adding the substrate error and the clock error due to temperature to the correction value table 92, thereby correcting the internal clock of the low-speed mode processing unit 81. That is, a configuration in which the substrate error 91 calculated at the time of shipment from the factory is not subtracted during the calibration may be employed. In this case, the substrate error 91 may not be stored in the storage unit 9.
The low-speed mode processing unit 81 may store a standard value of an error value related to the temperature and clock of the low-speed mode processing unit 81 in the correction value table 92 at the time of factory shipment. The low-speed mode processing unit 81 calculates a specific error value for each substrate by subtracting the standard value of the error value at the temperature obtained by the temperature sensor 13 from the measured clock during calibration. It is also possible to store the error 91 in the storage unit 9. Note that the low-speed mode processing unit 81 may calculate and average the inherent error value for each substrate at each temperature.

Further, the low speed mode processing unit 81 may perform calibration using values of the atmospheric temperature and the external environment temperature inside the image forming apparatus 1. At this time, the low speed mode processing unit 81 may perform calibration by changing the ambient temperature by moving each part of the image forming apparatus 1 instead of the heat generated by the processing of the low speed mode processing unit 81 itself. Further, the low speed mode processing unit 81 may perform calibration by changing the external environment temperature. The low speed mode processing unit 81 may perform calibration using a sensor such as humidity.
Furthermore, the low-speed mode processing unit 81 may include a temperature adjusting unit using a Peltier element or the like that raises or lowers the temperature, and may thereby perform calibration while adjusting the temperature.
The low speed mode processing unit 81 may calculate an error value regarding the relationship between the power supply voltage and the error value and store the error value in the low speed mode processing unit 81. At this time, similarly to the correction value table 92, the low speed mode processing unit 81 may create a table indicating the relationship between the power supply voltage and the error value. Further, the low speed mode processing unit 81 may create a table indicating the relationship among the power supply voltage, the error value, and the temperature.

The time measuring device and the time measuring method according to the embodiment of the present invention are not limited to the image forming apparatus, and can be applied to various devices that selectively use the high speed mode and the low speed mode.
Further, in the above-described embodiment, it has been described that separate control units are used for the high-speed mode and the low-speed mode, but it is also possible to use the same CPU when switching between the high-speed mode and the low-speed mode.

  Note that the configuration and operation of the above-described embodiment are examples, and it is needless to say that the configuration and operation can be appropriately changed and executed without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Original reading part 3 Original feeding part 4 Main body part 5 Stack tray 6 Operation panel part 7 Image forming part 8 Control part 9 Storage part 10 Image processing part 11 FAX transmission / reception part 12 Network transmission / reception part 13 Temperature sensor 14 High speed Clock section 21 Scanner 22 Platen glass 23 Document reading slit 31 Document placement section 32 Document discharge section 33 Document transport mechanism 41 Discharge port 42 Paper feed section 43 Paper transport path 44 Transport roller 45 Discharge roller 71 Photosensitive drum 72 Exposure section 73 Development Section 74 Transfer section 75 Fixing section 81 Low speed mode processing section 91 Substrate error 92 Correction value table 421 Paper feed cassette 422 Paper feed roller

Claims (3)

In an image forming apparatus including an image forming unit that forms an image on a sheet,
High-precision clock generation means for generating a high-precision clock;
A high-speed mode control unit that receives the high-precision clock of the high-precision clock generation unit and controls each unit including the image forming unit;
Low-speed mode control means having built-in clock generation means for generating a built-in clock slower than the high-precision clock;
Error storage means for storing an error value of the internal clock;
Temperature detecting means for detecting the temperature of the low speed mode control means;
Built-in clock correction means for correcting the error of the built-in clock based on the temperature detected by the temperature detection means and the error value of the built-in clock stored in the error storage means;
The image forming apparatus, wherein the low-speed mode control means controls each part using the internal clock corrected by the internal clock correction means. Built-in clock error measuring means for measuring an error of the built-in clock with the high-precision clock;
By changing the temperature of the low-speed mode control means, the built-in clock error measuring means measures the error of the built-in clock, creates a correction value table for correcting the deviation for each temperature, and stores it in the error storage means With calibration means,
The image forming apparatus according to claim 1, wherein the built-in clock correction unit corrects the built-in clock of the low-speed mode control unit based on the correction value table created by the calibration unit. High-precision clock generation means for generating a high-precision clock;
High-speed mode control means for receiving the high-precision clock of the high-precision clock generation means and controlling each part;
Low-speed mode control means having built-in clock generation means for generating a built-in clock slower than the high-precision clock;
Error storage means for storing an error value of the internal clock;
Temperature detecting means for detecting the temperature of the low speed mode control means;
Built-in clock correction means for correcting the error of the built-in clock based on the temperature detected by the temperature detection means and the error value of the built-in clock stored in the error storage means;
The low-speed mode control unit controls each unit using the built-in clock corrected by the built-in clock correction unit.

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