JP2005134449A - Image forming apparatus and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To properly set various control parameters by highly accurately detecting the environment in which an image forming apparatus, such as an electrophotographic copying machine or printer, is installed. <P>SOLUTION: The image forming apparatus includes a cooing fan 32 which cools the inside of the apparatus, and an ambient air temperature detection device 33, as an environmental detection sensor, which detects the environment in which the apparatus is installed. The ambient air temperature detection device 33 is disposed in the vicinity of the cooling fan 32, and alters control parameters for each of the parts of the apparatus on the basis of the detection information of the ambient air temperature detection device 33. The cooling fan 32 starts to operate in response to the input of an instruction to form images. After a predetermined length of time has elapsed from the start of the operation of the cooling fan 32, the environment in which the apparatus is installed is detected by the ambient air temperature detection device 33. The cooling fan 32 is stopped for the operation standby period of the apparatus. The operation of the cooling fan 32 starts at the same time as the start of the recording operation of the apparatus. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus such as an electrophotographic copying machine, a printer, and a facsimile, and a control method thereof.

  2. Description of the Related Art Conventionally, an image forming apparatus such as a laser printer detects a device installation environment such as temperature and humidity by a temperature sensor such as a thermistor or a humidity sensor disposed in the apparatus main body, and the temperature of the fixing device is determined based on the device installation environment information Various control parameters are appropriately determined.

  At that time, if an environmental detection sensor such as a temperature sensor or humidity sensor is installed inside the device, the temperature detected by the temperature sensor increases due to the effect of the self-heating of the device, or the recording material is heated. There is a risk that the detection value of the humidity sensor may be different from the outside air due to the influence of water vapor generated during fixing. In order to prevent these problems, the environment detection sensor is placed near the cooling fan of the device, and the outside air is blown to the environment detection sensor to prevent the temperature and humidity around the environment detection sensor from rising. It can be set as the structure which raises a precision.

In order to detect the device installation environment with higher accuracy, a method has also been proposed in which the detection value after a certain time from the start of rotation of the cooling fan is used for control in a configuration in which the cooling fan is rotated during standby standby of the device. (For example, refer to Patent Document 1). In this conventional example, the outside air temperature is detected during standby standby.
JP 2002-251121 A

  However, in the conventional image forming apparatus as described above, when the cooling fan drive is stopped during standby, the temperature inside the apparatus rises during standby, so the temperature sensor detects the temperature. It becomes higher than actual.

  Further, since the water vapor generated from the recording material diffuses inside the apparatus even after the apparatus is stopped, the humidity inside the apparatus is shifted to a higher level when the cooling fan is stopped during standby standby.

  In such a state, even if the outside air temperature is detected, an accurate value cannot be obtained. Therefore, there is not much meaning to disposing an environment detection sensor in the vicinity of the cooling fan.

  However, rotating the cooling fan during standby is not preferable in terms of noise and energy saving and should be avoided as much as possible.

  The present invention has been made in view of the above problems, and an object of the present invention is to detect an apparatus installation environment with high accuracy and to appropriately set various control parameters. And providing a control method thereof.

  In order to achieve the above object, an image forming apparatus according to the present invention includes a cooling fan that cools the inside of the apparatus and an environment detection sensor that detects an installation environment of the apparatus, and the environment detection sensor is disposed in the vicinity of the cooling fan. In addition to changing the control parameters of each part of the apparatus based on the detection information of the environment detection sensor, the cooling fan starts driving in response to an input of an image formation command, and detects the installation environment of the apparatus by the environment detection sensor Is performed after a predetermined time has elapsed since the start of driving of the cooling fan.

  The cooling fan is stopped when the apparatus is on standby and starts to be driven simultaneously with the start of the recording operation of the apparatus.

  In addition, a temperature detection element is used to detect and control the temperature of the heating body, and a heating device that discharges the recording medium by applying the thermal energy generated by the heating body to the recording material is discharged. According to the detection value of the element, the detection timing of the device installation environment by the environment detection sensor is changed.

  The temperature detection timing by the temperature detection element when the heating body is not heated is when an image formation command is input.

  The environment detection sensor is a temperature sensor.

  Further, the environment detection sensor is a humidity sensor.

  An image forming apparatus control method according to the present invention includes a cooling fan that cools the inside of the apparatus and an environment detection sensor that detects an installation environment of the apparatus, and the environment detection sensor is disposed in the vicinity of the cooling fan. An image forming apparatus control method for changing a control parameter of each part of the apparatus based on detection information of a sensor, wherein the cooling fan starts to be driven in response to an input of an image formation command, and the apparatus using the environment detection sensor The installation environment is detected after a predetermined time has elapsed since the start of driving of the cooling fan.

  According to the present invention, the apparatus installation environment can be detected with high accuracy, and various control parameters can be set appropriately.

  In other words, even when there is a possibility that the temperature and humidity inside the device may be different from the outside air, such as when the device is on standby or immediately after a printing operation, the surroundings of the environment detection sensor will be sufficiently leveled by the cooling fan to the outside environment. Therefore, the detected value can be made more accurate, and therefore various parameters of the image forming apparatus can be set to more appropriate values as compared with the conventional case.

  Further, since it is not necessary to drive the cooling fan during standby standby, noise prevention and energy saving can be achieved.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a cross-sectional view schematically showing a schematic configuration of an image forming apparatus according to an embodiment of the present invention. Here, an example of a laser printer 1 using an electrophotographic system is shown as an image forming apparatus.

  When a print command (image formation command) is input from a host computer (not shown), first, the main motor 2 is driven, and the recording material P is fed from the paper feed cassette 3 by the paper feed roller 4, and the conveyance path. Is sent to. The main motor 2 simultaneously drives the image forming unit such as the photosensitive drum 7 and the fixing device 19. Simultaneously with the drive of the main motor 2, the cooling fan 32 starts to rotate and cools the inside of the apparatus.

  In the vicinity of the cooling fan 32, an outside air temperature detection element 33 is provided as an environment detection sensor at a position where the outside air sent by the cooling fan 32 is directly blown, and various control parameters of the apparatus are changed based on the detected value. To do. In this embodiment, the control temperature of the fixing device 19 is switched according to the outside air temperature. For example, the control temperature is lowered when the outside air temperature is high, and the control temperature is raised when the outside air temperature is low.

  The recording material P fed from the paper feed cassette 3 is reliably transported at a stable speed by the transport roller pair 5 disposed on the transport path. The conveyance state of the recording material P is detected by the top sensor 6, and the passage timing of the recording material P at the position of the top sensor 6 is used to determine various timings such as image formation and fixing temperature control.

  The photosensitive drum 7 is uniformly and uniformly charged by the charging roller 8 and then irradiated with a laser beam L corresponding to an image signal output from the laser scanning exposure device 9 to form an electrostatic latent image on the surface. Is done. At this time, the laser scanning exposure apparatus 9 reflects the laser light L to the polygon mirror 11 rotated by the polygon motor 10, focuses the reflected light on the lens 12, and irradiates the photosensitive drum 7 with the folding mirror 13 or the like. .

  The latent image on the photosensitive drum 7 is visualized as a toner image with toner selectively attached thereto by the developing device 14, and conveyed to the transfer unit T as the photosensitive drum 7 rotates. In the transfer portion T, the transfer roller 15 applies an electric field having a polarity opposite to that of the toner from the back surface (back surface) of the recording material P, thereby transferring the toner image onto the sheet. Untransferred toner remaining on the photosensitive drum 7 without being transferred is accommodated in a waste toner container 17 by a cleaning blade 16.

  The recording material P that has received the transfer of the toner image is guided to the conveyance guide 18 and guided to the fixing device 19. The fixing device 19 serving as a heating device applies heat and pressure to the recording material P at the fixing nip N, and fixes the toner image transferred onto the recording material P onto the recording material.

  In the present embodiment, the fixing device 19 uses a heating device of a so-called film heating system (Japanese Patent Laid-Open No. 4-44075 to 44083), and a ceramic heater 51 as a heating body is fixed to and supported by a heater holder 52. This is pressed against a pressure roller 54 as a pressure body through a fixing film 53 by a pressure means (not shown). The fixing film 53 is driven to rotate by the rotational drive of the pressure roller 54 and conveys the recording material P introduced into the nip N. The heater 51 generates heat when energized, and the printer control device 20 controls the temperature of the heater 51 based on a value detected by a thermistor 55 that is a temperature detection element of the heater 51.

  This film heating method has a small heat capacity of the heater and can quickly bring the heater to the fixing temperature, but it is more susceptible to the outside air temperature, so it is better to use a control that changes the fixing temperature according to the outside air temperature. Preferred fixing properties are obtained.

  The energization of the heater 51 of the fixing device 19 is started almost simultaneously with the start of driving of the main motor 2. Then, the recording material P on which the toner image is fixed passes through a paper discharge sensor 21 that detects a paper discharge state, and is discharged onto the tray 23 by a pair of paper discharge rollers 22. When the discharge of the recording material P is completely finished, the main motor 2 is stopped and the printing operation is finished.

  During this time, the cooling fan 32 continues to be driven to rotate, taking outside air into the apparatus to suppress the temperature rise in the apparatus, but when the printing operation is finished and the apparatus is stopped, the cooling fan 32 rotates after a predetermined time. To stop. Therefore, the cooling fan 32 is in a non-driven state when the apparatus is on standby.

  FIG. 2 is a cross-sectional view showing an example of arrangement positions of the cooling fan 32 and the outside air temperature detection element 33.

  The cooling fan 32 is attached to an exterior 35 of the laser printer 1, and the exterior 35 is provided with a louver 34. The outside air temperature detection element 33 is disposed in the vicinity of the inside of the cooling fan 32, and the outside air sucked in the direction of the arrow A by the rotational driving of the cooling fan 32 is directly blown.

  That is, the direction of the wind generated by the cooling fan 32 is from the outside to the inside of the apparatus, and the cooling fan 32 of this embodiment is a so-called suction type. The outside air temperature detecting element 33 is arranged at a position away from the heat source so that it is not easily affected by heat from the main motor 2, the fixing device 19, or the power supply board (not shown) as a heat source. Is preferred.

  The outside air temperature detecting element 33 can always monitor the temperature, but it is suitable to use a detected value at the start of the printing operation as a value reflected in the control during the printing operation. If the detected value at the start of printing is different from that before the start of printing (for example, when the power is turned on), it is natural to assume a change in the outside air temperature. The updated one should be considered to reflect the most outside temperature.

  However, it is not unlikely that the temperature detected by the outside air temperature detecting element 33 is different from the outside air temperature due to the temperature rise inside the apparatus during standby standby until the start of printing. For this reason, in this embodiment, the detection of the outside air temperature is performed not after the start of the printing operation but after a predetermined time has elapsed since the start of the operation.

  FIG. 3 is a diagram showing the timing of detecting the outside air temperature in the present embodiment.

  First, when the apparatus starts a printing operation and the main motor 2 starts driving, the cooling fan 32 also starts driving almost simultaneously. Thereafter, while the printing operation is continued as described above, the outside air temperature detection by the outside air temperature detecting element 33 is performed after a predetermined time t1 has elapsed from the start of the printing operation.

  Thus, the detected value after the outside air temperature detecting element 33 is cooled for a predetermined time by the cooling fan 32 is the influence of the temperature rise of the apparatus in standby due to the outside air being directly blown to the outside air temperature detecting element 33. Is a more accurate value that eliminates as much as possible.

  The detection of the outside air temperature by the outside air temperature detecting element 33 may be performed at any time after the start of the printing operation until the detected value is actually used for controlling the apparatus. When the fixing temperature of the fixing device 19 is determined based on the detection value of the outside air temperature detecting element 33 as in this embodiment, the outside air temperature is detected before the recording material P reaches the fixing device 19. It ’s fine.

  For example, when the time from when the printing operation starts until the recording material P reaches the fixing device 19 is 5.0 seconds, the fixing device 19 may be controlled to the fixing temperature after 5.0 seconds. The time t1 can take any value within 5.0 seconds. However, in order to allow the fixing device 19 to rise to the fixing temperature with a certain margin before the recording material P enters, it is better to set the time to about 1.0 seconds shorter than 5.0 seconds. good. Further, if the value of the time t1 is made too long, the effect of the temperature rise of the apparatus accompanying the printing operation will appear, so it is preferable that the time t1 is as short as possible.

  As described above, in this embodiment, it is possible to detect the apparatus installation environment with high accuracy and appropriately set various control parameters.

  That is, since the outside air temperature detection element 33 detects the outside air temperature after a predetermined time has elapsed since the start of the printing operation, the outside air temperature can be measured with higher accuracy while eliminating the influence of the temperature rise inside the apparatus as much as possible. As a result, control parameters such as the fixing temperature can be set to appropriate values according to the outside air temperature.

  Here, in the above example, the detection timing of the outside air temperature of the outside air temperature detecting element 33 is set after the start of the driving of the main motor 2, but only the cooling fan 32 is driven prior to the start of the driving of the main motor 2. May be detected. FIG. 4 shows the timing of external temperature detection at this time.

  When a print signal is input to the apparatus, a printing operation is started. First, the cooling fan 32 is driven to blow outside air to the outside air temperature detecting element 33. At this time, only the cooling fan 32 is driven without driving the main part of the apparatus such as energization heating to the main motor 2, the polygon motor 10, and the fixing device 19. When the predetermined time t2 elapses, driving of the main part of the apparatus that has been stopped is started, and when the predetermined time t1 elapses, the outside air temperature detection element 33 detects the outside air temperature.

  In this case, a series of printing operations such as feeding of the recording material P, image formation, and fixing have been performed since the elapse of time t2, and the detected outside temperature is reflected in the setting of the fixing temperature of the fixing device 19.

  In this example, the driving of the main part of the apparatus is earlier than the outside air temperature detection timing t1, but if necessary, the driving can be started later than the outside air temperature detection or simultaneously with the outside air temperature detection. .

  When the outside air temperature is detected in the sequence as described above, the outside air temperature detecting element 33 can be cooled by the cooling fan 32 before the heat source such as the main motor 2 or the fixing device 19 is driven. The value can be accurate.

  In this embodiment, the outside air temperature is detected by the temperature sensor as an example of detecting the installation environment of the apparatus. However, it goes without saying that the humidity of the outside air may be detected by using a humidity sensor. Humidity can be detected in exactly the same sequence as temperature detection, and parameters such as fixing temperature and transfer voltage can be appropriately set according to the humidity information.

  An image forming apparatus such as the laser printer 1 has a larger temperature rise during the printing operation than during the standby state for a long time. Therefore, the outside temperature detected immediately after the printing operation has a large error. In particular, when the printing operation is performed again immediately after the continuous printing operation, if only a few minutes have passed since the previous printing, it is better to use the value detected during the previous printing as the outside temperature. However, there may be a case where the power of the apparatus is turned on (ON) / off (OFF) after the previous printing operation, and data such as the previous detected value and elapsed time are cleared.

  In such a case, the control parameter can only be set based on the detected value of the outside air temperature during the printing operation. However, when the temperature rise inside the apparatus is large, the cooling time in the sequence as in the first embodiment described above. Insufficient outside air temperature may not be detected.

  In this embodiment, assuming such a case, the temperature rising state of the apparatus is estimated at the start of the printing operation, and the cooling time of the outside air temperature detecting element 33 by the cooling fan 32 is changed accordingly.

  In other words, when it was estimated that the temperature of the apparatus was high and it was not long before continuous printing was performed, it was estimated that the cooling time was lengthened to reliably cool the outside temperature detecting element, and the apparatus was not heated. Sometimes, the cooling time is shortened and the printing operation is performed quickly.

  FIG. 5 shows a table of the detection timing of the outside air temperature of this embodiment, and FIG. 6 shows a table of detection values by the temperature detection element 33 and the driving time of the cooling fan 32.

  First, when a print signal is input, the value of the thermistor 55 of the fixing device 19 is detected, and this detected value is fed back to the printer control device 20. If the detection value of the thermistor 55 is high, it can be estimated that the time has not passed so much since the fixing device was heated by the previous printing operation, and the temperature rise inside the apparatus is high, and the detection value of the thermistor 55 is normal. If the value is almost the same as the outside air temperature, it is estimated that printing has not been performed for a while and the temperature inside the apparatus is low.

  Based on the detection value of the thermistor 55, the printer control device 20 sets the cooling time t3 and the outside air temperature detection timing t4 by the cooling fan 32 at the start of the printing operation with reference to the table of FIG.

  Then, driving of the cooling fan 32 is started, and driving of the main motor 2 and the like is started after the elapse of time t3, and a series of printing operations are performed. Thereafter, when the time t4 has elapsed from the input of the print signal, the outside air temperature detection element 33 detects the outside air temperature.

  With such a configuration, the cooling operation to the outside air temperature detecting element 33 by the cooling fan 32 is performed longer as the internal temperature of the apparatus is predicted to be higher, so that the outside air temperature detecting element 33 has a higher accuracy in detecting the outside air temperature. Can be improved.

  In the above example, the outside air temperature is detected after the start of driving of the main motor 2 under all conditions. However, in the state where the temperature inside the original apparatus is high, such as immediately after continuous printing, the main temperature is detected. When the main part of the apparatus such as the motor 2 is driven, the temperature is likely to rise again. Therefore, even if cooling is performed by the cooling fan 32, the accuracy of the detected temperature of the outside air temperature detecting element 33 may be lowered.

  Therefore, in order to ensure the cooling of the outside air temperature detecting element 33, it is more preferable that the outside air temperature is detected before the main motor 2 is driven when the temperature detected by the thermistor 55 is high. On the other hand, when the temperature detected by the thermistor 55 is low, it is difficult to increase the temperature inside the apparatus. Therefore, it is better to detect the outside air temperature after starting the driving of the main motor 2 from the viewpoint of shortening the printing time.

  In the present embodiment, such a setting may be made according to the detected temperature of the thermistor 55. For example, the cooling time t3 and the outside air temperature detection timing t4 may be set based on the cooling time table shown in FIG.

  In the table of FIG. 7, when the temperature detected by the thermistor is less than 50 ° C. and 50 ° C. or more and less than 70 ° C., the outside air temperature is detected after the main motor 2 starts to be driven. T3 and t4 are set so that the outside air temperature is detected before.

  In this embodiment, the cooling fan 32 is rotated at the time of cooling the outside air temperature detecting element 33 so as to enhance the cooling effect. FIG. 8 shows a timing chart of this embodiment.

  When a print signal is input and the apparatus starts a printing operation, the main motor 2 starts driving and the cooling fan 32 also starts driving. At this time, the cooling fan 32 rotates at a rotation speed R2 (rpm) larger than the rotation speed R1 (rpm) during normal rotation. When the predetermined time t5 elapses, the outside air temperature detection element 33 detects the outside air temperature and switches the rotation speed of the cooling fan 32 to the normal rotation R1 (rpm).

  The rotation speed of the cooling fan 32 may be switched by switching the voltage supplied to the cooling fan 32.

  In such a configuration, since the outside air temperature detecting element is cooled more strongly by increasing the number of rotations of the cooling fan 32 until the outside air temperature detecting element 33 detects the outside air temperature, the outside air temperature can be detected more accurately. Become. Since the cooling fan 32 reduces the rotational speed after detecting the outside air temperature, an increase in noise caused by increasing the rotational speed of the cooling fan 32 can be suppressed to only a few seconds at the start of the printing operation.

  The embodiment of the present invention has been described above. In the present invention, as described above, when the operation of the image forming apparatus starts, the cooling fan blows a sufficient amount of outside air on the environment detection sensor, and then the environment detection sensor detects the apparatus installation environment. Therefore, it is possible to eliminate the influence of the internal temperature rise during the standby state of the apparatus and the change in temperature and humidity accompanying the recording operation, and to detect the apparatus installation environment more accurately than in the past. Further, according to the present invention, since it is possible to accurately detect the installation environment without driving the cooling fan during standby standby, it is possible to prevent noise and save energy due to rotation of the cooling fan during standby.

  In addition, since the operation history of the device is determined from the temperature of the heating body at the time of non-heating and the detection timing of the device installation environment by the environment detection sensor is changed accordingly, When there is a large difference from the outside air, for example, the time for blowing the outside air to the environment detection sensor by the cooling fan should be lengthened, and the temperature and humidity around the environment detection sensor should be equalized to the outside air before detecting the installation environment. The detection value can be made more accurate.

Sectional drawing which shows schematic structure of the image forming apparatus by the Example of this invention Sectional drawing which shows the arrangement position of the outside temperature detection element in the image forming apparatus of Example 1. Timing chart of outdoor temperature detection in the image forming apparatus of Embodiment 1 Timing chart of outdoor temperature detection in the image forming apparatus of Embodiment 1 Timing chart of outdoor temperature detection in the image forming apparatus of Embodiment 2 FIG. 10 is a diagram illustrating a table of values detected by the temperature detection element of the heating device and driving time of the cooling fan in the image forming apparatus according to the second embodiment. FIG. 10 is a diagram illustrating a table of values detected by the temperature detection element of the heating device and driving time of the cooling fan in the image forming apparatus according to the second embodiment. Timing chart of outdoor temperature detection in the image forming apparatus of Embodiment 3

Explanation of symbols

1 Laser printer (image forming device)
2 Main motor 3 Paper feed cassette 4 Paper feed roller 5 Carrying roller pair 6 Top sensor 7 Photosensitive drum 8 Charging roller 9 Laser scanning exposure device 10 Polygon motor 11 Polygon mirror 12 Lens 13 Folding mirror 14 Developing device 15 Transfer roller 16 Cleaning blade 17 Waste toner container 18 Transport guide 19 Fixing device 20 Printer control device 21 Paper discharge sensor 22 Paper discharge roller pair 23 Tray 32 Cooling fan 33 Outside air temperature detection element 34 Louver 51 Ceramic heater 52 Heater holder 53 Fixing film 54 Pressure roller 55 Thermistor P Recording material L Laser light T Transfer part N Fixing nip

Claims (7)

A cooling fan that cools the inside of the apparatus and an environment detection sensor that detects the installation environment of the apparatus. And change
The cooling fan starts to be driven in response to an input of an image formation command, and detection of an apparatus installation environment by the environment detection sensor is performed after a predetermined time has elapsed from the start of driving of the cooling fan. apparatus.   2. The image forming apparatus according to claim 1, wherein the cooling fan is stopped when the apparatus is on standby and starts to be driven simultaneously with the start of the recording operation of the apparatus.   A heating device that detects and controls the temperature of the heating body with a temperature detection element, applies heat energy generated by the heating body to the recording material, and discharges the recording material, and the temperature detection element when the heating body is not heated. The image forming apparatus according to claim 1, wherein the detection timing of the apparatus installation environment by the environment detection sensor is changed according to the detection value.   4. The image forming apparatus according to claim 3, wherein the temperature detection timing by the temperature detection element when the heating body is not heated is when an image formation command is input.   The image forming apparatus according to claim 1, wherein the environment detection sensor is a temperature sensor.   The image forming apparatus according to claim 1, wherein the environment detection sensor is a humidity sensor. A cooling fan that cools the inside of the apparatus and an environment detection sensor that detects the installation environment of the apparatus. The environment detection sensor is arranged in the vicinity of the cooling fan, and control parameters of each part of the apparatus based on detection information of the environment detection sensor An image forming apparatus control method for changing
The cooling fan is started to be driven in response to an input of an image formation command, and the installation environment of the apparatus is detected by the environment detection sensor after a predetermined time has elapsed from the start of driving of the cooling fan. Control method for image forming apparatus.

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