JP2004212539A - Thermal fixing device and image forming apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal fixing device in which the stand-by time for starting fixing is shortened while realizing power-saving, and an image forming apparatus using it. <P>SOLUTION: The thermal fixing device by which an unfixed toner image is melted and fixed on transfer paper while holding and feeding the transfer paper carrying the unfixed toner image by a heating body performing heating by being supplied with electric power is provided with an electric power supply control means (a control part 21 or the like) to control the supply of the electric power to the heating body (a heating roller 10a) in accordance with the use state of the image forming apparatus provided with the thermal fixing device and a sheet number counting means 21a to count the number of sheets on which the image forming apparatus performs image forming within unit-time, and shifting time for shifting operation from a stand-by mode to a power-saving mode is decided by the stage of counting the number of printing sheets per unit-time. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a heat fixing device and an image forming apparatus using the heat fixing device, and more particularly, to a heat fixing device in which power saving is realized and a waiting time for fixing rise is shortened, and an image forming apparatus using the heat fixing device. About.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in an image forming apparatus (a laser printer, a copying machine, etc.) of a type that thermally fixes toner, in order to reduce wasteful heat fixing power consumption during standby when the apparatus (image forming apparatus) is not operating, The following measures were taken. That is, if the standby state continues for a certain period of time, a power saving mode in which power is saved by lowering the set temperature of thermal fixing or turning off the power supply itself to thermal fixing is adopted (for example, Patent Document 1). .
[0003]
[Patent Document 1]
JP 2001-42691 A (paragraph number 0007-0022, FIG. 3)
[0004]
[Problems to be solved by the invention]
However, the transition to the conventional power saving mode is a transition time set in the image forming apparatus in advance (entering the power saving mode after a lapse of a certain time), and the transition time depends on the device usage status of the user who is different from each other. If the length is too long, the power consumption for the transition time may be lost.
[0005]
Conversely, if the transition time is too short, the opportunity for the heat fixing temperature to be unnecessarily lowered will increase for the next device user (user) due to the long elapsed time of the power saving mode. For this reason, there is a problem that a “fixing start time wait” occurs every time printing (copying) is started from the power saving mode.
[0006]
SUMMARY OF THE INVENTION It is an object of the present invention to provide a heat fixing device which realizes power saving and has a shorter waiting time for fixing to rise, and an image forming apparatus using the heat fixing device.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention according to claim 1 is to transfer the unfixed toner image onto a transfer sheet while nipping and conveying the transfer sheet carrying the unfixed toner image by a heating element heated by supplying power. In the heat fixing device to be worn,
The power supply to the heating element (the heating roller 10a in FIG. 3) is controlled according to the use condition of the image forming apparatus (the color laser printer CLP in FIG. 1) including the thermal fixing device (the thermal fixing device 10). Power supply control means (control unit 21, relay 22, triac 26, thermistor 28, cover switch 29, etc. in FIG. 3);
Number counting means (reference numeral 21a in FIG. 3) for counting the number of images formed by the image forming apparatus in a unit time;
The transition time from the standby mode to the power saving mode is determined by the number of prints per unit time (FIG. 6).
[0008]
In this case, the transition time for shifting to the power saving mode is determined by the actually measured number of prints per unit time, so that the transition time is automatically set in accordance with the frequency of use of the user's device (image forming apparatus). Will be done. Therefore, the transition time to the power saving mode can be set according to the user's usage status of the device, so that the waiting time can be reduced and the power consumption of the device (image forming apparatus) can be suppressed.
[0009]
According to a second aspect of the present invention, there is provided a heat fixing device for fusing the unfixed toner image onto the transfer sheet while nipping and transferring the transfer sheet carrying the unfixed toner image by a heating element that is heated by supplying power.
Power supply control means for controlling power supply to the heating element in accordance with a use condition of an image forming apparatus including the heat fixing device;
A job interval counting means (reference numeral 21b in FIG. 3) for monitoring an image forming operation on a job basis and counting a job interval from the end of one job to the start of the next job;
The transition time for transition from the standby mode to the power saving mode is determined based on the job interval.
[0010]
In this way, the transition time for shifting to the power saving mode is determined by the actually measured job interval, so that the transition time is automatically set according to the frequency of use of the device (image forming apparatus) by the user. . Therefore, the transition time to the power saving mode suitable for the user can be set, so that the waiting time can be reduced and the power consumption of the device can be suppressed.
[0011]
According to a third aspect, in the thermal fixing device according to the first or second aspect,
The power supply control unit is configured to include a preheating mode in which power supply to the heating element is reduced to save power, and a sleep mode in which power supply to the heating element is turned off.
[0012]
With this configuration, the power saving control performed by the power supply controller includes a preheating mode and a sleep mode. By automatically setting the transition time to these modes in accordance with the frequency of use of the device by the user, the user is provided with the power saving control. The transition time to each power saving mode can be set. Therefore, the waiting time can be reduced, and the power consumption of the device (thermal fixing device) can be suppressed.
[0013]
According to a fourth aspect, in the thermal fixing device according to the first or second aspect,
The transition time to transition to the power saving mode can be switched between an automatic setting and a manual setting.
[0014]
According to this configuration, the power saving transition time automatically set according to the frequency of use of the user can be manually set, so that the usage status of various devices (image forming apparatuses) is further considered, The convenience for the user can be improved.
[0015]
According to a fifth aspect, the image forming apparatus (the color laser printer CLP in FIG. 1) is configured to use the thermal fixing device according to the first to fourth aspects.
With this configuration, the transition time to the power saving mode can be set according to the usage status of the image forming apparatus by the user, so that the waiting time can be reduced and the power consumption of the image forming apparatus can be suppressed.
[0016]
Further, since the transition time for shifting to the power saving mode is determined by the actually measured job interval, the transition time is automatically set according to the frequency of use of the image forming apparatus by the user. Therefore, the transition time to the power saving mode can be set according to the user, so that the waiting time can be reduced and the power consumption of the image forming apparatus can be suppressed.
[0017]
The power saving control by the power supply control unit includes a preheating mode and a sleep mode. The transition time to these modes is automatically set in accordance with the frequency of use of the image forming apparatus by the user, so that the mode suitable for the user is set. The transition time to each power saving mode can be set. Therefore, the waiting time can be reduced, and the power consumption of the image forming apparatus can be suppressed.
[0018]
In addition, since the power saving transition time automatically set according to the frequency of use of the user can be manually set, the convenience for the user can be improved in consideration of various use situations of the image forming apparatus. it can.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described based on the illustrated embodiments.
FIG. 1 is a schematic side sectional view of the color laser printer of the present embodiment.
[0020]
As shown in FIG. 1, a color laser printer CLP includes a photoreceptor belt 1 as a latent image carrier, a charger 2 disposed around the photoreceptor belt 1, and a writing unit for performing laser irradiation as image forming means. 3 and a developing device 4 (4M, 4C, 4Y, 4BK) for four colors, a photosensitive member cleaning means 5, and a discharge lamp 6.
[0021]
The image forming apparatus further includes an intermediate transfer belt 7 that intermediately holds an image (latent image) formed on the photoreceptor belt 1, and a secondary transfer roller 8 that is in opposing contact with the intermediate transfer belt 7 and performs transfer on the transfer paper P. Is provided. The image forming apparatus further includes a cleaning roller 9 for cleaning the intermediate transfer belt 7, a thermal fixing device 10 for thermally fixing the toner image on the transfer paper P, and a paper feed tray 11 for storing the transfer paper P.
[0022]
The photoreceptor belt 1 is uniformly charged by a charger 2, irradiates a laser beam from a writing unit 3, writes a latent image on the photoreceptor belt 1, and brings a developing unit 4 into contact with the photoreceptor belt 1 to form a toner image. Are visualized. The image formed on the photoreceptor belt 1 is transferred onto the intermediate transfer belt 7 again.
[0023]
After the re-transfer, the discharged toner on the photoreceptor belt 1 is removed by the photoreceptor cleaning unit 5, and is discharged by irradiating an LED with a QL lamp (not shown) serving as a discharging unit, and is discharged on the photoreceptor. Is completed.
[0024]
In the case of the full-color mode, images of four colors (M: magenta, C: cyan, Y: yellow, BK: black) are sequentially formed by the above process, and the timing is adjusted on the intermediate transfer belt 7 by dividing four times. To superimpose the images. Then, transfer paper P is fed from the paper feed tray 11 with respect to the superimposed state of the images, and a bias is applied to the transfer paper P while conveying the intermediate transfer belt 7 and the secondary transfer roller 8 to the pressing portion. Transfer to
[0025]
Thereafter, the transfer paper P to which the toner has been transferred is conveyed to the heat fixing device 10 and is fixed by passing through a nip between the heat roller 10a and the pressure roller 10b in the heat fixing device 10 described below. The paper is then discharged to the paper discharge unit.
[0026]
Next, the configuration of the fixing device will be described.
FIG. 2 is a longitudinal sectional view of the fixing device.
As shown in FIG. 2, the transfer paper P enters from the right side of the heat fixing device 10, and the toner T on the transfer paper is fixed between the nips of the heating roller 10a and the pressure roller 10b, and is transferred to the paper discharging unit. Conveyed.
In this fixing, the toner T on the transfer paper is melted by the heat of the heating roller 10a and fused to the transfer paper P.
[0027]
FIG. 3 is a diagram illustrating a cross-sectional view of the fixing device and a control system.
As shown in FIG. 3, the control system includes a control unit 21 including a CPU, a ROM, a RAM, and the like, a relay 23 for turning on / off the AC power supply 22, and a switching transistor 24 for turning on / off the relay 23. , A first control driver 25 for controlling on / off of the transistor 24.
[0028]
Further, the control system includes a triac 26 for controlling on / off of the heater 10c, a first control driver 25 for controlling on / off of the triac 26, a thermistor 28 for detecting the current temperature of the heating roller 10a, A cover switch 29 for detecting opening and closing of a cover (not shown) of the laser printer CLP.
[0029]
Next, the operation of the fixing device will be described.
As shown in FIG. 3, the heating roller 10a is pressed by a pressing roller 10b, which is a pressing unit, and is driven to rotate by a driving source (not shown). The heating roller 10a has a built-in heating heater 10c as a heating source.
[0030]
One end of the heater 10c is connected to one end of an AC power supply 22 via a contact 23a of a relay 23, and a triac 26 is connected between the other end of the heater 10c and the other end of the AC power supply 22. The triac 26 is driven by a first control driver 25, and the control driver 25 is controlled on / off by the control unit 21.
[0031]
The coil of the relay 23 is connected between the power supply of 24 V DC and the ground via the switching transistor 24. Then, the first control driver 25 turns on / off the transistor 24 to turn on / off the relay 23.
[0032]
Therefore, when the relay 23 is turned on and the triac 26 is turned on, power is supplied to the heater 10c from the AC power supply 22 via the triac 26 for the first time, and the heater 10c is turned on and the heating roller 10a is turned on. Heating.
[0033]
A thermistor 28, which is a temperature detecting element, is arranged on an outer peripheral portion of the heating roller 10a, and detects a temperature of a central portion of the heating roller 10a. The detection signal from the thermistor 28 is input to the control unit 21. The control unit 21 converts the input analog temperature detection signal into a digital signal by a built-in AD converter, and obtains temperature data on the outer periphery of the heating roller 10a according to a program.
The control unit 21 controls the triac 26 via the first control driver 25 based on the temperature detection signal, and controls the turning on / off of the heater 10c.
[0034]
Further, a detection signal is input to the control unit 21 from a cover switch (cover SW) 29 that detects whether a main body cover (door) (not shown) of the color laser printer CLP is opened. When the main body cover is opened, the relay 23 is turned off by turning off the first control driver 25 and turning off the transistor 24. This turns on the heater 10c.
[0035]
When the main body cover is closed, the control section 21 turns on the first control driver 25 to turn on the transistor 24, thereby turning on the relay 23. Therefore, when the main body cover is open, the heater 10c does not light up.
[0036]
Next, the operation of the present embodiment will be described.
FIG. 4 is a flowchart illustrating the control of energization of the heater 10c by the control unit 21 in the present embodiment.
[0037]
As shown in FIG. 4, a loop is always formed at regular intervals, and it is monitored whether there is a factor for turning off the fixing (step S1). For example, when there is a fixing OFF factor such as “sleep mode” or “main body cover open” in response to a command from an image forming apparatus control unit (not shown), the control unit 21 turns off the relay 23 (step S2). Then, the heater 10c is also turned off (step S3), and the power supply to the heater 10c is stopped.
[0038]
If there is no fixing OFF factor (step S1: none), the cycle timer counted by the control unit 21 is set to, for example, one second and the timer is started (step S4).
[0039]
Next, a process of acquiring the current temperature value from the thermistor 28 is performed (step S5), and the amount of power (on time) to the heater 10c is calculated from the difference between the current temperature value acquired by the control unit 21 and the control target temperature (step S5). Step S6). As a method of calculating the amount of energization, a method such as a PID calculation method of a known technique is used.
[0040]
Then, the multiplier (gain) of an arithmetic expression including three terms of a proportional term, a differential term, and an integral term is set to a set value in consideration of a model-specific condition such as the heat capacity of the heating roller 10a and the W (watt) number of the heating element. By doing so, it is possible to achieve optimal temperature control without overshoot and control ripple.
[0041]
A timer value corresponding to the calculation result of the energization time is set in the energization time timer, and the timer is started (step S7), and at the same time, the output to the heater 10c is turned on (step S8).
Further, in the processing after step S8, a waiting process is performed in a loop of step S9 until the started energization time timer expires, and when the energization time has elapsed, the output to the heating heater 10c is turned off. (Step S10).
[0042]
Next, a waiting process is performed in a loop of step S11 until the started periodic timer times out. When the cycle time is up, the energization processing loop for one cycle has been completed, so the process returns to step S1 and the energization processing is performed again in the next cycle.
[0043]
FIG. 5 is a time chart of an output waveform showing an output signal from the control unit 21, and turns on / off the heater 10c as described above.
As shown in FIG. 5, the control unit 21 performs an operation to determine the ON duty at regular intervals, and determines Ton (as described above, this time is determined from the difference between the current temperature value and the control target temperature). Output is turned on at the same time, and the output is turned off at the same time as the time of Ton elapses.
[0044]
After the output is turned off, the output is kept turned off until the next operation cycle comes. By repeating this cycle, the difference between the current temperature value and the control target temperature is eliminated.
[0045]
(1) First Embodiment Next, a first embodiment of the present invention will be described with reference to FIGS.
FIG. 6 is a table referred to in the control of FIG. 7 described below, and specifically shows the relationship between the number of prints per day and the power saving shift time.
FIG. 7 is a flowchart of the present embodiment, and shows a power saving shift time setting process.
[0046]
As shown in FIG. 6, the control stage is set to step 1 and the power saving transition time is set to 5 minutes until the number of prints per day is 100 or less. In the control stage step 2 in which the number of prints per day is from 100th to 1000th, the power saving transition time is set to 30 minutes.
[0047]
In the control stage step 3 where the number of prints per day is from the 1000th to the 2000th, the power saving transition time is set to 60 minutes.
In the control stage step 4 where the number of prints per day is 2000 or more, the power saving transition time is set to 90 minutes.
As described above, the power saving transition time is gradually increased as the number of prints per day increases.
[0048]
In other words, when the image forming apparatus is installed in an office or the like, if the number of prints per day is 100 or less, the frequency of use of the image forming apparatus is low, and the standby time with the power on is long. Since it can be determined, a short power saving transition time (in this case, transition in 5 minutes) was set. That is, when the number of sheets is 100 or less, the image forming apparatus enters the power saving mode in the non-use state for 5 minutes, so that unnecessary power consumption can be prevented.
[0049]
Conversely, if the number of prints is 2,000 or more, it is determined that the standby time with the power on is short, and a long power saving transition time (90 minutes) is set. In other words, when the number of sheets is 2,000 or more, the image forming apparatus is hardly in an unused state, so that the power saving transition time is set to 90 minutes. Printing is possible.
[0050]
As shown in FIG. 7, first, in step S11, the value of the 24-hour elapsed timer Tday is set to "0" and the timer is started. Next, the process waits in step S12, and if there is a print command (step S12: YES), the process proceeds to step S13 to perform print processing for the print command received in step S11. Then, in step S14, the number of printed sheets is counted up as a sheet counter C1.
[0051]
Next, in step S15, the value of the 24-hour elapsed timer Tday is checked, and if the count has not expired (step S15: NO), the process returns to step S12, and waits for a print command. If the count of the 24-hour elapsed timer Tday has expired (step S15: YES), the process proceeds to step S16, and the value of the print number counter C1 that has been counted up in step S14 is fixed (Cfix). ). The process from counting of the number of sheets to finalization is performed by the number counting means 21a of FIG.
[0052]
Next, in step S17, an equation is calculated as Cave = (Cave + Cfix) / 2 in order to make the determined number of prints Cfix into the accumulated averaged data up to now. Then, in step S18, the power saving transition time is selected from the number of prints Cave per day with reference to the table defined in FIG. Finally, the process proceeds to step S19, in which the determined power saving shift time is stored, and the process ends.
The aim in this process is to count the number of prints every day (elapse of 24 hours) as the usage frequency data of the device, and determine the power saving transition time that matches the usage frequency.
[0053]
(2) Second Embodiment FIG. 8 is a flowchart of this embodiment, and shows a power saving shift time setting process.
In this flowchart, when a print command is issued from the host (the control unit of the main body of the color laser printer CLP), processing is performed once for each print, and the process proceeds to step S21.
[0054]
Next, in step S22, a printing process for the print command received in step S21 is performed.
Next, the process proceeds to step S23, where it is checked whether or not the next print command currently being executed is accumulated. If it is not accumulated (step S23: NO), continuous printing is interrupted and one job ends. Therefore, in step S24, the time elapsed timer J1 after the job is set to 0 and the timer is started. In step S25, a continuous print flag indicating that continuous printing is being performed is reset.
[0055]
In step S23, if the print commands are accumulated (step S23: YES), it is possible to determine that the job is continuing because it is continuous with the previous one, so the process proceeds to step S26, and the continuous print flag is set. Check
[0056]
Only when the flag changes from “0” to “1”, that is, from the non-printing state to the continuous printing state (step S26: YES), the process proceeds to step S27 and subsequent steps.
If the value is other than "0" to "1", the time elapsed timer J1 after the job is set to "0" in step S24 and the timer is started, and the continuous print flag is reset in step S25. After that, the process returns to step S21 to wait for a print command.
[0057]
On the other hand, in step S27, the value of the post-job time elapsed timer J1 started in step S24 is determined (referred to as Jfix). Next, in step S28, an equation is calculated as Jave = (Jave + Jfix) / 2 in order to make the finalized post-job time elapsed timer Jfix the accumulated averaged data so far.
[0058]
Then, in step S29, the power saving transition time is replaced with the post-job time elapsed timer Jfix and stored. Then, after resetting the continuous print flag in step S30, the process returns to step S21, and enters a state of waiting for a print command again.
[0059]
The purpose of this process is to aggregate print job intervals as device use frequency data and determine a power saving transition time that matches the use frequency.
In the above processing, the job interval (time) is performed by the job interval counting means 21b.
[0060]
The above is the embodiment according to the present invention, but it is not limited only to the above example. For example, the configuration in which the heater 10c is arranged only in the heating roller has been described. However, a configuration in which one heating heater 10c is provided in each of the heating roller and the pressure roller, or two heaters 10c are provided in the heating roller. It may have a configuration to have.
[0061]
Although a color laser printer is used as an example of the image forming apparatus, the present invention can be applied to other image forming apparatuses such as a copier, a facsimile, and a digital multifunction peripheral having a plurality of functions such as a copier and a facsimile.
[0062]
【The invention's effect】
As described above, according to the present invention, the following effects can be exerted.
According to the first aspect of the present invention, since the transition time for shifting to the power saving mode is determined by the actually measured number of prints per unit time, the transition time is automatically set according to the frequency of use of the device by the user. Will be.
Thereby, the transition time to the power saving mode suitable for the user can be set, so that the waiting time can be reduced and the power consumption of the device can be suppressed.
[0063]
According to the second aspect of the present invention, the shift time for shifting to the power saving mode is determined by the actually measured job interval, so that the shift time is automatically set in accordance with the frequency of use of the device by the user.
Thereby, the transition time to the power saving mode suitable for the user can be set, so that the waiting time can be reduced and the power consumption of the device can be suppressed.
[0064]
According to the third aspect of the present invention, the power saving control of the power supply control means includes a preheating mode and a sleep mode, and the mode transition time for these modes is automatically set according to the frequency of use of the device by the user. By doing so, the transition time to each power saving mode suitable for the user can be set. Therefore, the waiting time can be reduced, and the power consumption of the device can be suppressed.
[0065]
According to the fourth aspect of the present invention, by incorporating means for manually setting the power saving transition time automatically set in accordance with the frequency of use of the user, the use status of various devices is further taken into consideration. The convenience for the user can be improved.
[0066]
According to the fifth aspect of the present invention, the transition time to the power saving mode can be set according to the user's use state of the image forming apparatus, so that the waiting time can be reduced and the power consumption of the image forming apparatus can be suppressed. .
[0067]
Further, since the transition time to the power saving mode can be set according to the user, the waiting time can be reduced, and the power consumption of the image forming apparatus can be suppressed.
Further, the waiting time can be reduced, and the power consumption of the image forming apparatus can be suppressed.
[0068]
In addition, the power saving transition time automatically set according to the frequency of use of the image forming apparatus by the user can be manually set. Can be raised.
[Brief description of the drawings]
FIG. 1 is a schematic sectional side view of a color laser printer using a heat fixing device of the present invention.
FIG. 2 is a side sectional view of the heat fixing device according to the embodiment of the present invention.
FIG. 3 is a diagram illustrating a cross-sectional view of a heat fixing device and a control system according to the first embodiment.
FIG. 4 is a flowchart showing control of energization of a heater by a control unit in the embodiment.
FIG. 5 is a time chart of an output waveform showing an output signal from a control unit in the embodiment.
FIG. 6 is a diagram specifically showing a relationship between the number of prints per day and a power saving shift time in the embodiment.
FIG. 7 is a flowchart illustrating a power saving shift time setting process according to the first embodiment.
FIG. 8 is another flowchart showing the power saving transition time setting process in the embodiment.
[Explanation of symbols]
CLP Color laser printer P Transfer paper T Toner 1 Photoreceptor belt 2 Charger 3 Writing unit 4 Developer (4M, 4C, 4Y, 4BK)
Reference Signs List 5 Photoconductor cleaning means 6 Static elimination lamp 7 Intermediate transfer belt 8 Secondary transfer roller 9 Cleaning roller 10 Heat fixing device 10a Heating roller 10b Pressure roller 10c Heater 11 Paper feed tray 21 Control unit 22 AC power supply 23 Relay 23a Relay contacts 24 switching transistor 25 first control driver 26 triac 27 second control driver 28 thermistor 29 cover switch

Claims (5)

In a heat fixing device that fuses the unfixed toner image onto the transfer paper while nipping and transferring the transfer paper carrying the unfixed toner image by a heating element that is heated by power supply,
Power supply control means for controlling power supply to the heating element in accordance with a use condition of an image forming apparatus including the heat fixing device;
The image forming apparatus includes a number counting means for counting the number of images formed in a unit time,
A thermal fixing device, wherein a transition time for transitioning from a standby mode to a power saving mode is determined based on the number of prints per unit time. In a heat fixing device that fuses the unfixed toner image onto the transfer paper while nipping and transferring the transfer paper carrying the unfixed toner image by a heating element that is heated by power supply,
Power supply control means for controlling power supply to the heating element in accordance with a use condition of an image forming apparatus including the heat fixing device;
A job interval counting unit that monitors an image forming operation on a job basis and counts a job interval from the end of one job to the start of the next job;
A thermal fixing device, wherein a transition time for transition from a standby mode to a power saving mode is determined based on the job interval. The thermal fixing device according to claim 1, wherein
The heat fixing device according to claim 1, wherein the power supply control unit includes a preheating mode in which power supply to the heating element is reduced to save power, and a sleep mode in which power supply to the heating element is turned off. The thermal fixing device according to claim 1, wherein
A heat fixing device, characterized in that a transition time for transition to the power saving mode can be switched between an automatic setting and a manual setting. An image forming apparatus using the heat fixing device according to claim 1.

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