JP5556610B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus provided with a cooling fan for cooling a fixing device, and in particular, an improvement is made to rotational drive control of a cooling fan. The image forming apparatus according to the present invention is applied to a copying machine, a printer, a facsimile, and the like.

2. Description of the Related Art Conventionally, an image forming apparatus is provided with a fixing device for fixing a toner image formed on recording paper to the recording paper, and a cooling fan for preventing the periphery of the fixing device from becoming high temperature. As such a cooling fan control method, the following modes are widely known.
(A) At the end of the job, the cooling fan is rotated for a certain time.
(B) At the end of the job, the driving time is determined based on the number of prints of the job, and the cooling fan is rotated.
(C) The cooling fan is rotated while the temperature inside the apparatus is equal to or higher than a preset temperature.

  Here, “job” means a copying operation in response to a single pressing operation of the copy start button by the user. That is, when an ADF (automatic document feeder) provided in the image reading unit is used, when a plurality of documents are set on the ADF, the copy start button is pressed once. A copying operation is performed on a plurality of recording sheets. That is, the “job” in this case includes a plurality of prints. On the other hand, when a document is placed on the platen glass and copied one by one, a copy operation for one sheet of recording paper is basically executed by pressing the copy start button once. In other words, the “job” in this case includes one printed sheet. However, even when a document is placed on the platen glass and copied one by one, if the number of copies is set to a plurality of sheets, a copy operation is performed on a plurality of recording sheets, “Job” includes a plurality of prints.

  As described above, when copying is performed by placing originals one by one on the platen glass, when a plurality of originals are continuously copied, multiple jobs are intermittently performed. Will be performed continuously. For this reason, even if the number of prints included in a single job is one, the total number of prints is increased by repeating the job, and the heat generation time of the heat source is increased accordingly. The peripheral part of the vessel tends to be hot.

  When the operation as described above is performed, the control methods (A) and (B) do not take into account the total number of actually printed sheets. Cooling may be insufficient, and parts may be deformed and deteriorated. Conversely, when the number of jobs is small, the cooling fan is rotated more than necessary, and power is consumed wastefully. In the control method (C), the fan is rotated until the temperature inside the apparatus reaches a set value regardless of the number of prints, so that the inside of the apparatus is sufficiently cooled. However, it is necessary to provide a plurality of temperature sensors in order to detect the temperature of the fixing device and the peripheral portion of the fixing device, and it is inevitable that the manufacturing cost of the image forming apparatus is increased accordingly.

As an alternative to the control methods (A) to (C) as described above, a cooling fan control method as disclosed in Patent Documents 1 and 2 is known. In the cooling fan control method according to Patent Document 1, the cooling fan is driven when the cumulative number of copies reaches a certain value, and the cooling fan is stopped when a certain operation pause time or more has elapsed. When the cooling fan stops, the cumulative number of copies is reset to zero.
In Patent Document 2, the cooling time by the cooling fan is determined based on the usage status data calculated from the lighting time and extinguishing time of the heat source (light source). When the usage status data exceeds a certain value, the cooling time corresponding to the usage status data is determined, and the usage status data is reset. Then, cooling is performed by rotating the cooling fan in a state where image formation of the apparatus is prohibited. Patent Documents 1 and 2 are both cooling fan control methods for cooling the optical system of the image forming apparatus.

Japanese Unexamined Patent Publication No. 63-159873 (FIG. 2) JP-A-8-202245 (paragraph numbers 0031 and 0032, FIGS. 4 and 6)

  In the control method of Patent Document 1, the cooling fan is not rotated unless the cumulative number of copies reaches a constant value. When a job with one printed sheet is intermittently repeated, driving of the cooling fan is started. There is a risk that the waiting time until the start will be prolonged. For this reason, the fixing device or the periphery of the fixing device becomes hot during the standby time, and there is a possibility that the deformation of the parts or the deterioration of the parts may occur. Moreover, since the time for which the cooling fan rotates is constant, the cooling time may be insufficient. Further, it is expected that the fan stops in a state of insufficient cooling and the cumulative number of copies is reset to zero. In this case, the number of prints is accumulated from zero when the temperature of the fixing device is high, and the fixing device may immediately reach a high temperature state.

  In the control method of Patent Document 2, the cooling time of the cooling fan is determined based on the usage status data of the heat source, so that it is possible to cool without excess or deficiency. However, since the copying operation (image forming operation) is prohibited when the cooling fan is rotating, it is inevitable that the copy standby time becomes long.

  An object of the present invention is to calculate an appropriate driving time required for cooling the fixing device and the peripheral portion of the fixing device from the accumulated number of printed sheets even when a plurality of jobs are intermittently performed continuously. An object of the present invention is to provide an image forming apparatus capable of reliably cooling a fixing device or the like. An object of the present invention is to suppress power consumed by a cooling fan by rotating the cooling fan without excess or deficiency.

  The present invention is directed to an image forming apparatus including a fixing device 3 and a cooling fan 10 that cools the fixing device 3. The accumulated number counting means 27 that can count the number of prints across a plurality of jobs and the cooling fan 10 based on the accumulated number N counted by the accumulated number counting means 27 every time one job is completed. And a fan driving time calculating unit 28 for calculating the driving time T of the fan. Further, a storage unit 34 that stores the drive time T calculated by the fan drive time calculation unit 28, a control unit 29 that controls the driving of the cooling fan 10 during the drive time T stored in the storage unit 34, and integration And a resetting means 30 for resetting the cumulative number N of the number counting means 27.

  The temperature detecting means 18 for detecting the temperature inside the apparatus is provided, and the reset means 30 is a cumulative number counting means 27 when the temperature detected by the temperature detecting means 18 becomes equal to or lower than a preset temperature H2. The accumulated number N is reset.

  The fixing device 3 preferably includes a fixing roller 15 having a heat source 17, and the temperature detecting unit 18 detects the surface temperature H of the fixing roller 15.

  In the image forming apparatus according to the present invention, the number of printed sheets is accumulated and counted over a plurality of jobs, and the driving time T of the cooling fan 10 is calculated based on the printed accumulated number N every time one job is completed. Is calculated and stored in the storage unit 34. Then, the cooling fan 10 is rotationally driven by the control means 29 during the stored drive time T. In addition, a reset means 30 for resetting the accumulated number N of the accumulated number counting means 27 to an initial value of zero is provided. According to this, even when the job is intermittently performed continuously, the driving time of the cooling fan 10 is based on the accumulated number N counted by the accumulated number counting unit 27 across the jobs every time the job is completed. T is calculated and stored in the storage unit 34. During the driving time T stored in the storage unit 34, the control unit 29 rotates the cooling fan 10 to cool the fixing unit 3 and the fixing unit peripheral portion. Further, the integrated means N can be reset as appropriate by the reset means 30 to prevent the integrated number N from increasing more than necessary.

  As described above, since the driving time T of the cooling fan 10 is calculated and changed every time the job is completed, even if the job is performed intermittently and continuously, an appropriate driving according to the cumulative number N is performed. During the time T, the cooling fan 10 can be driven to rotate. Therefore, it is possible to reliably cool the fixing device 3 and the periphery of the fixing device with the cooling fan 10. Further, by resetting the accumulated number N by the reset means 30, it is possible to prevent the accumulated number N from being increased more than necessary and the drive time T of the cooling fan 10 from being prolonged. Power consumption can be suppressed.

  Here, the count of the cumulative number does not necessarily span a plurality of jobs. This is because when the accumulated number N is zero and the interval between the execution of a single job and the generation of the next job is long, the reset means 30 sets the accumulated number N to zero during this period. This is because it may be reset. In this case, the number of printed sheets is not accumulated across a plurality of jobs, and therefore the accumulated number N may be counted only for a single job.

  When the temperature detected by the temperature detecting means 18 becomes equal to or lower than a preset temperature H2, the accumulated number N of the accumulated number counting means 27 is reset. Here, the set temperature H2 is set to a temperature at which the inside of the apparatus does not need to be cooled by the cooling fan 10. According to this, it is possible to prevent the difference between the drive time T calculated from the integrated number N and the drive time T necessary for actual cooling. For example, when one sheet is printed at a temperature at which the inside of the apparatus does not need to be cooled, the cooling fan 10 may have a driving time T for one sheet. However, if the cumulative number N is not reset, the fan drive time calculation unit 28 calculates the drive time T that is the number obtained by adding one to the previous cumulative number N. As described above, when the cumulative number N is 1 or more, the driving time T of the cooling fan 10 equal to or longer than the driving time T necessary for actual cooling is calculated, and the cooling fan 10 is rotated uselessly. . Therefore, when the inside of the apparatus is sufficiently cooled, the accumulated number N is reset to the initial value, the difference in the driving time T is eliminated, and the appropriate driving time T is calculated, The fixing device 3 in the apparatus and the periphery of the fixing device can be appropriately cooled. Moreover, the power consumption of the cooling fan 10 can also be suppressed by driving the cooling fan 10 without rotating it more than necessary.

  If the temperature detecting means 18 is configured to detect the surface temperature H of the fixing roller 15, it can be reliably determined whether or not the fixing roller 15 including the heat source 17 has a set temperature H2 that does not need to be cooled. Can be detected. Further, since the temperature detecting means 18 can be used as a temperature sensor for monitoring the temperature condition of the fixing roller 15, it is not necessary to separately provide a temperature sensor or the like for performing feedback control of the heat source 17, leading to cost reduction of the apparatus.

1 is a diagram illustrating a schematic configuration of an image forming apparatus according to the present invention. 1 is a front view illustrating a schematic configuration of an image forming apparatus. It is a flowchart which shows operation | movement of the driving method of a cooling fan.

(Embodiment) FIGS. 1 to 3 show an embodiment in which an image forming apparatus according to the present invention is applied to a multifunction machine having a copy function and a facsimile function. In addition, the front-rear direction, the left-right direction, and the up-down direction in the present embodiment follow the notations such as the arrows in FIG.

  In FIG. 2, the multifunction device 1 includes a main body portion 4 on which an image forming portion 2 and a fixing device 3 are arranged, an image reading portion 5 on the upper portion of the main body portion 4, and the like. A recording paper transport path 8 is provided between the paper feed cassette 6 disposed on the main body 4 and the discharge section 7 at the top of the main body 4. The image forming unit 2 is disposed in the lower part of the conveyance path 8 and the fixing device 3 is disposed in the upper part. A cooling fan 10 is disposed in the vicinity of the fixing device 3, and exhaust of the cooling fan 10 is provided so as to be discharged toward the rear surface of the main body 4.

  The image forming unit 2 includes a photosensitive drum 11, a toner cartridge 12, and the like, and forms an image by transferring a toner image onto recording paper fed from the paper feed cassette 6. An operation panel 13 having various operation buttons is provided on the front surface of the image reading unit 5, and an automatic document feeder (ADF) 14 is provided on the upper surface side. An image of a spelled document such as a book can be read in a state of being placed on the platen glass on the upper surface of the image reading unit 5, and a sheet-like document can be read through the automatic document feeder 14. .

  In FIG. 1, the fixing device 3 includes a fixing roller 15 and a pressure roller 16. The fixing roller 15 is formed of a hollow cylindrical member, and a halogen lamp (heat source) 17 is disposed therein. A thermistor (temperature detection means) 18 for detecting the temperature condition of the fixing device 3 is disposed on the outer peripheral surface of the fixing roller 15, and the thermistor 18 detects the surface temperature H of the fixing roller 15. The amount of heat generated by the halogen lamp 17 is feedback-controlled based on the surface temperature of the fixing roller 15 detected by the thermistor 18, and the amount of power supplied to the halogen lamp 17 by the triac 19 is increased or decreased. Thus, if the temperature control of the fixing device 3 and the confirmation of the temperature state are performed with one thermistor 18, the cost of the apparatus can be reduced as compared with a case where a separate temperature sensor or the like is provided. The pressure roller 16 is configured by disposing a foam made of rubber or plastic on the outer periphery of the roller shaft, and is pressed and urged toward the fixing roller 15 by a spring (not shown).

  As shown in FIG. 1, the copier 1 includes a CPU (Central Processing Unit) 21, a ROM (Read Only Memory) 22, an SRAM (Static Random Access Memory) 23, a modem 24, an NCU (Network Control Unit) 25, and an integrated chip. A set 26 is provided. Further, a counter (integrated sheet count means) 27 that accumulates and counts the number of prints, a fan drive time calculator 28 that calculates the drive time T of the cooling fan 10 based on the accumulated number of counters 27, and a fan drive time calculator A timer (control means) 29 for controlling the driving of the cooling fan 10 and a reset means 30 are provided for the drive time T calculated in 28. These are connected via a bus 31 so that they can communicate with each other. A printer control circuit 32, a scanner 33, a memory (storage unit) 34, and the like are connected to the integrated chip set 26. The memory 34 stores the image data read by the scanner 33, the cumulative number N, the driving time T, and the like. The cooling fan 10, the thermistor 18, and the triac 19 are connected to the printer control circuit 32. The operation of the multifunction machine 1 is controlled by the CPU 21.

  Next, a control method of the cooling fan 10 will be described using the flowchart shown in FIG. When a print command is input from the operation panel 13 of the copier 1 in the print standby state, the timer 29 starts rotating the cooling fan 10 (S1) and starts measuring time (S2). Next, the surface temperature H of the fixing roller 15 detected by the thermistor 18 is compared with a set temperature H2 that requires cooling of the fixing roller 15 (S3). If the surface temperature H is lower than the set temperature H2 (YES in S3), the reset means 30 resets the accumulated number N of the counter 27 to an initial value of zero (S4).

  Next, electric power is supplied from the triac 19 to the halogen lamp 17 to start warming up the fixing roller 15 (S5). After the warm-up is started, the surface temperature H of the fixing roller 15 detected by the thermistor 18 is compared with the fixing temperature H1 at which the fixing device 3 can perform the fixing operation (S6). If the surface temperature H is equal to or higher than the fixing temperature H1 (YES in S6), the recording paper is transported from the paper feed cassette 6 through the transport path 8 and passes through the image forming unit 2 and the fixing device 3. The paper is discharged to the discharge unit 7 and printed (S7). When printing is performed, the cumulative number N of the counter 27 is incremented by 1 (S8) and stored in the memory 34. It is confirmed whether the designated number of prints has been printed and the job has been completed (S9). If the job has not been completed (NO in S9), the process returns to S7 to continue printing.

  When the job is completed (YES in S9), the fan driving time calculation unit 28 calculates the driving time T of the cooling fan 10 corresponding to the accumulated number N (S10), and stores the calculated driving time T in the memory 34 ( S11). Here, it is confirmed whether or not the next print designation is input from the operation panel 13 (S12). If no print designation is input (NO in S12), the time measured by the timer 29 is confirmed (S13). If the driving time T of the timer 29 has not elapsed (NO in S13), the process returns to S12, loops through S12 and S13, and waits for the input of the next print command. If the time measured by the timer 29 exceeds the drive time T stored in the memory 34 during the loop (YES in S13), the timer 29 stops the rotation of the cooling fan 10 (S14). Thereafter, the process returns to the initial print standby state and waits for a print command to be input from the operation panel 13.

  When the next print command is input from the operation panel 13 while S12 and S13 are looped (YES in S12), the process returns to S3 and the surface temperature H detected by the thermistor 18 is compared with the set temperature H2. To do. If the surface temperature H is higher than the set temperature H2 (NO in S3), the reset means 30 does not reset the accumulated number N of the counter 27 to zero and executes S5 to S9. At this time, since the accumulated number N has not been reset, the accumulated number N is added to the accumulated number N of the previous value stored in the memory 34. When the job is completed (YES in S9), the fan driving time calculation unit 28 calculates the driving time T of the cooling fan 10 corresponding to the integrated number N from the new integrated number N counted by the counter 27 (S10). The calculated drive time T is overwritten and stored in the memory 34 (S11).

  Next, S12 and S13 are looped to wait for the input of a print command from the operation panel 13, and the next print command is input before the driving time T overwritten and stored in the memory 34 elapses. If YES (YES in S12), the process returns to S3 and the control from S3 to S13 is performed. If the driving time T stored in the memory 34 elapses before the next print command is input (YES in S13), the timer 29 stops the rotation of the cooling fan 10. Thereafter, the process returns to the initial print standby state and waits for a print command to be input from the operation panel 13. In this way, the driving time T of the cooling fan 10 based on the accumulated number N printed across the jobs is calculated every time the job is completed and is overwritten and stored in the memory 34, so that it corresponds to the accumulated number N at the end of the job. An appropriate driving time T can be obtained. Therefore, even when a plurality of jobs are intermittently performed continuously, the cooling fan 10 is rotationally driven for an appropriate driving time T to reliably cool the fixing device 3 and the periphery of the fixing device. be able to.

  When the print command is input in S12 and the process returns to S3, the fixing device 3 is sufficiently cooled, and the surface temperature H of the fixing roller 15 detected by the thermistor 18 is lower than the set temperature H2. The reset means 30 resets the accumulated number N of the counter 27 to zero, and then starts counting the accumulated number N. Thereby, when the surface temperature H of the fixing roller 15 is sufficiently cooled, the fixing device 3 and the periphery of the fixing device can be appropriately cooled in the driving time T calculated from the integrated number N after reset. it can. As described above, the fixing number 3 and the peripheral portion of the fixing device can be appropriately cooled by resetting the integrated number N to the initial value and calculating the appropriate driving time T. Moreover, the cooling fan 10 can be driven without rotating more than necessary, and the power consumption of the cooling fan 10 can be suppressed.

  In this embodiment, the cooling fan 10 starts rotating immediately after the print command. However, after the driving time T of the cooling fan 10 is calculated, the cooling fan 10 may start rotating. Similarly, the timer 29 starts timing immediately after the print command, but may start timing after calculating the driving time T of the cooling fan 10. The counter 27 and the timer 29 can be incorporated into the CPU 21 as a program.

1 Image forming device (multifunction machine)
3 Fixing device 10 Cooling fan 15 Fixing roller 17 Heat source (halogen lamp)
18 Temperature detection means (thermistor)
27. Accumulated number counting means (counter)
28 Fan drive time calculation unit 29 Control means (timer)
30 reset means 34 storage unit (memory)
H Surface temperature H2 Set temperature N Total number of sheets T Drive time

Claims (2)

In an image forming apparatus comprising a fixing device and a cooling fan for cooling the fixing device,
An accumulated number counting means capable of accumulating and counting the number of printed sheets across a plurality of jobs;
A fan driving time calculation unit that calculates the driving time of the cooling fan based on the total number of sheets counted by the total number counting unit each time one job is completed;
A storage unit for storing the driving time calculated by the fan driving time calculating unit;
Control means for controlling driving of the cooling fan during the driving time stored in the storage unit;
Resetting means for resetting the cumulative number of the cumulative number counting means;
It has temperature detection means to detect the temperature inside the device,
The image forming apparatus according to claim 1 , wherein the reset unit resets the accumulated number of the accumulated number counting unit when the temperature detected by the temperature detecting unit is equal to or lower than a preset set temperature . The fixing device includes a fixing roller having a heat source,
The image forming apparatus according to claim 1 , wherein the temperature detecting unit detects a surface temperature of the fixing roller .

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