JP3638915B2 - Power saving device for image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a power saving apparatus for reducing power consumption of an image forming apparatus.
[0002]
[Prior art]
In a conventional image forming apparatus, a toner image formed in an image forming unit composed of a photoconductor is transferred onto a transfer paper fed from a paper feed unit to a photoconductor position, and then transferred to a transfer paper at a fixing unit. It is fixed and discharged.
[0003]
The fixing unit generally employs a heat roller fixing system composed of a heating roller and a pressure roller from the viewpoint of speeding up and safety. In the heat roller fixing method, the pressure roller is pressed against the heating roller at a predetermined pressure, and the transfer paper on which the toner image is transferred is passed between the heating roller and the pressure roller and heated to the fixing temperature. The toner image is melted and fixed on the transfer paper by the heat from the heating roller and the pressure of the pressure roller. As the heater of the heating roller, a heater having a large heat capacity and large power consumption is employed in order to prevent a heat change. Further, the image forming apparatus includes a cooling fan in the vicinity of the fixing unit, and the temperature of members disposed around the fixing unit is suppressed by releasing heat from the fan. .
[0004]
On the other hand, it is known that the image forming apparatus is not used for a short time after the main power is turned on. Therefore, conventionally, in order to save power of the image forming apparatus, when the non-use state continues for a predetermined time, the image forming apparatus is configured to shift from the standby state to the power saving mode. In this power saving mode, the heater is put into a complete stop state or a preheat state in which the temperature level is lower than the fixing temperature, and the operation of the fan or the like is stopped, and only the display indicating that it is in the power saving mode is performed. It was.
[0005]
[Problems to be solved by the invention]
However, in the conventional image forming apparatus, since the level of energization to the heater and the stop of the fan operation are simultaneously performed by shifting to the power saving mode, heat is dissipated by the heat capacity of the heater. As a result, the temperature of the peripheral member of the fixing portion is increased, and this has adversely affected the peripheral member made of synthetic resin, such as thermal deformation and thermal fatigue.
[0006]
SUMMARY An advantage of some aspects of the invention is that it provides a power saving device for an image forming apparatus that prevents a temperature rise of a peripheral member of a fixing unit after shifting to a power saving mode.
[0007]
It is another object of the present invention to provide a power saving device for an image forming apparatus that saves power as much as possible.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 is driven by the fixing section for fixing the transfer toner image onto the transfer paper by the heat of the heater heated to the fixing temperature, and driven by the first cooling capacity. In an image forming apparatus including a cooling unit that discharges heat around the fixing unit,
Mode control means for shifting to a power saving mode for stopping the heating operation of the heater to the fixing temperature when an instruction for image formation is not performed for a predetermined period of time;
Stop control means for stopping the driving of the cooling means delayed from the time of transition to the power saving mode;
Temperature detecting means for detecting the temperature in the apparatus body;
A discriminating means for discriminating whether or not the previous detected temperature and the current detected temperature by the temperature detecting means showed a flat tendency after the transition to the power saving mode;
When the determination means determines that the previous detected temperature and the current detected temperature tend to be flat, the stop control means stops the driving of the cooling means .
[0009]
According to this configuration, when an instruction for image formation is not performed continuously for a predetermined time, the mode shifts to the power saving mode, the heating operation to the fixing temperature by the heater is stopped, and the shift to the power saving mode is started. The driving of the cooling means is stopped with a delay. Therefore, power saving can be achieved by stopping the heating operation of the heater in the power saving mode, and adverse effects due to the temperature rise of the fixing unit can be prevented.
[0010]
Furthermore, devices are detected temperature is in the body, when after migration to power-saving mode and the temperature detect current and previous detected temperature showed leveled off drives stop cooling means, the temperature rise of the fixing portion by which Is prevented and the power consumption is further reduced.
[0011]
According to a second aspect of the present invention, there is provided a fixing unit for fixing the transfer toner image onto the transfer paper by the heat of the heater heated to the fixing temperature, and the heat around the fixing unit driven by the first cooling capacity. In an image forming apparatus provided with cooling means for discharging,
Mode control means for shifting to a power saving mode for stopping the heating operation of the heater to the fixing temperature when an instruction for image formation is not performed for a predetermined period of time;
Stop control means for stopping the driving of the cooling means delayed from the time of transition to the power saving mode;
Temperature detecting means for detecting the temperature in the apparatus body;
After the transition to the power saving mode, a determination unit that determines whether the temperature increase rate of the previous detection temperature and the current detection temperature by the temperature detection unit is moderate,
When the determining means determines that the rate of temperature increase between the previously detected temperature and the current detected temperature is moderate, the stop control means stops the driving of the cooling means.
[0012]
The invention of claim 3 is the power saving device of the image forming apparatus according to claim 1,
The determination means determines whether or not the temperature increase rate of the previous detection temperature and the current detection temperature by the temperature detection means is moderate after the transition to the power saving mode.
When the determining means determines that the rate of temperature increase between the previously detected temperature and the current detected temperature is moderate, the stop control means stops the driving of the cooling means .
[0013]
According to these configurations, the detected temperature in the apparatus body, the driving of the cooling means is stopped when the previously detected temperature and the temperature rise rate of the currently detected temperature after the transition to power-saving mode becomes moderate Therefore, power consumption is further reduced.
[0014]
According to a fourth aspect of the present invention, there is provided a power saving device for the image forming apparatus according to any one of the first to third aspects, wherein an instruction to execute image formation is issued after the shift to the power saving mode. In this case, image forming control means for waiting for the start of the copying operation until the fixing unit returns to the fixing temperature and starting the copying operation when the fixing portion returns to the fixing temperature is provided.
[0015]
According to this configuration, when there is an instruction to execute image formation after shifting to the power saving mode, the start of the copying operation is waited until the fixing unit returns to the fixing temperature, and the temperature returns to the fixing temperature. Since the copying operation is started at this time, it is possible to reliably prevent the occurrence of copying failure. In addition, since other operations can be performed during the time until the fixing unit returns to the fixing temperature, workability can be improved.
[0016]
The invention of claim 5 is the power saving device of the image forming apparatus according to any one of 請 Motomeko 1 to claim 4, shifting to the Power Saving Mode the cooling capacity of the cooling means Cooling control means for reducing the cooling capacity to a second cooling capacity lower than the first cooling capacity is provided .
[0017]
According to this configuration, when the mode is shifted to the power saving mode, the cooling capacity of the cooling unit is decreased from the first cooling capacity to the second cooling capacity, thereby reducing power consumption for driving the cooling unit.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 3 is a front view showing an embodiment of the internal configuration of the image forming apparatus to which the present invention is applied.
[0019]
The apparatus main body 1 of the image forming apparatus includes a sheet feeding unit 10 disposed in a lower portion, a sheet conveying unit 20 disposed in the upper portion, an image forming unit 30 disposed in the upper portion, and an upper portion. In addition to the optical section 40 disposed, the contact glass 2 disposed in the center of the upper surface and the document retainer 3 for pressing the document on the contact glass 2 are disposed.
[0020]
The paper feed unit 10 includes a paper feed cassette 11 for storing transfer paper and a paper feed roller 12 disposed at the right end of the paper feed cassette 11. The paper feed cassette 11 includes a paper placing plate 13 that is biased upward, and transfer paper is stacked on the paper placing plate 13. The paper feed roller 12 has a half-moon cross section and is disposed with a flat portion facing downward in a stopped state so as not to interfere with the attachment and detachment of the paper feed cassette 11.
[0021]
The optical unit 40 includes an exposure lamp 41, a reflecting plate 42, reflecting mirrors 43a, 43b, 43c, 43d, 43e, 43f, and a lens unit 44. The exposure lamp 41, the reflecting plate 42, the reflecting mirror 43a, and the reflecting mirror 43b, 43c is reciprocally driven in the left-right direction in the figure at a predetermined speed, and scans the document image during the forward movement to generate a light image of the document.
[0022]
The image forming unit 30 includes a photosensitive member 31 that is rotatably supported, and a main charging unit 32, a developing unit 33, a transfer separation unit 34, a cleaning unit 35, and a charge eliminating unit from the upstream side in the rotation direction around the photosensitive member 31. A portion 36 is provided. The main charging unit 32 uniformly charges the surface of the photoconductor 31 to a predetermined potential, and an area for exposing a light image of an original is provided immediately downstream thereof, and an electrostatic latent image is formed on the surface of the photoconductor 31 by this light image. It has come to be. The developing unit 33 performs development by attaching toner to the electrostatic latent image. The transfer separation unit 34 transfers the toner image on the surface of the photoconductor 31 to the transfer paper, and also separates the transferred transfer paper from the photoconductor 31. The cleaning unit 35 cleans the toner remaining on the surface of the photoreceptor 31 after the transfer. The neutralization unit 36 is for erasing residual charges on the surface of the photoreceptor 31.
[0023]
The paper transport unit 20 is driven from the upstream side in the transport direction in synchronization with the scanning timing of the transport roller pair 21 and the optical unit 40 that transport the transfer paper fed from the paper feed unit 10 toward the photoreceptor 31. A registration roller pair 22, a fixing unit 23 that transports the transfer toner image on the transfer paper separated from the photoreceptor 31, and a discharge roller pair 25 that discharges the transfer paper onto a discharge tray 24 are provided.
[0024]
The fixing unit 23 includes a heating roller 23a and a pressure roller 23b. The heating roller 23a includes a heater 23c disposed inside the roller and a temperature sensor (not shown) that detects the temperature of the roller surface. The transfer toner image is suitably applied to the transfer paper by on / off control of the heater 23c. It is maintained at a fixing temperature for fixing. The pressure roller 23b is formed of a material whose surface is slightly softer than the surface of the heating roller 23a, and is pressed against the heating roller 23a with a required urging force.
[0025]
In addition, the apparatus main body 1 includes a cooling fan 26 disposed at an appropriate position above the fixing unit 23 and a temperature sensor 37 disposed at an appropriate position of the image forming unit 30. The cooling fan 26 suppresses an increase in temperature of the fixing unit 23 and members disposed in the vicinity thereof by blowing air outward from a not-shown vent hole formed in the apparatus main body 1. The temperature sensor 37 is a thermistor or the like and detects the temperature in the apparatus main body 1.
[0026]
FIG. 1 is a block diagram showing a control configuration of the image forming apparatus.
[0027]
The image forming apparatus includes a control unit 4 including a microcomputer having a timer function, and operation control of each unit is performed by the control unit 4.
[0028]
The operation unit 50 is disposed at an appropriate position on the surface of the apparatus main body 1, and includes a print key 51 for starting a copying operation, a set number key 52 for setting the number of copies for each document, and a magnification for setting a copy magnification. Operation keys such as a setting key 53 are provided.
[0029]
The display unit 60 is disposed at an appropriate position on the surface of the apparatus main body 1 and includes an LCD panel, an LED, and the like, and displays the number of copies set by the number of copies setting key 52 and the copy magnification set by the magnification setting key 53. is there. In addition, the display unit 60 includes a power saving mode display unit 61 that displays a message to that effect when shifting to a power saving mode to be described later.
[0030]
The control unit 4 includes a ROM 4a for storing a control program and the like and a RAM 4b for temporarily storing various data. When the print key 51 is pressed, the control unit 4 is set according to the contents set by operating the operation keys such as the magnification setting key 53. The copying operation is started by controlling the respective sections of the paper transport unit 20, the image forming unit 30, and the optical unit 40.
[0031]
In addition, when the operation of the operation key of the operation unit 50 is not continuously performed for a predetermined time, the control unit 4 shifts the image forming apparatus to the power saving mode according to a procedure described later. The control unit 4 is configured to return the image forming apparatus to a normal operation state when an operation is performed on the operation key of the operation unit 50 in the power saving mode.
[0032]
In the power saving mode, only the display operation of the power saving mode display unit 61 is performed, and the other display operations of the display unit 60 and the energization operation to the heater 23c of the heating roller 23a are stopped. Note that after the transition to the power saving mode, the rotation drive of the cooling fan 26 is stopped with a delay as described later.
[0033]
The control unit 4 controls the rotation of the cooling fan 26, under normal operating conditions is rotated at the first rotation speed V _1, the rotational speed from the transition point the first to power-saving mode The cooling fan 26 is rotated at the second rotation speed V ₂ lower than V ₁ . Incidentally, it is set to V ₂ = V _1/2 in this embodiment.
[0034]
When the print key 51 is pressed in the power saving mode, the start of the copying operation is waited until the heating roller 23a returns to the fixing temperature, and the copying operation is started when the temperature returns to the fixing temperature. As a result, it is possible to reliably prevent the occurrence of copy defects. In addition, since other work can be performed during the time from when the print key 51 is pressed until returning, workability can be improved.
[0035]
Next, the operation of the image forming apparatus having the above configuration will be described.
[0036]
When the copy magnification is set by the magnification setting key 53, the number of copies is set by the number of copies setting key 52, and the print key 51 is pressed, the copying operation is started. That is, the light from the exposure lamp 41 is reflected by the original placed on the contact glass 2, and the reflected light is guided to the lens unit 44 through the reflecting mirrors 43a to 43c, and then the reflecting mirrors 43d to 43f are moved. Then, the photoreceptor 31 is exposed. At this time, the surface of the photoconductor 31 is uniformly charged by the charging unit 32, and the transfer area of the photoconductor 31 is exposed by the optical unit 40 to form an electrostatic latent image. Next, the charged toner supplied from the developing unit 33 to the photoconductor 31 adheres to the electrostatic latent image and is developed.
[0037]
On the other hand, the uppermost transfer paper layered on the paper placement plate 13 is fed in contact with the cylindrical portion of the paper feed roller 12 that is rotationally driven, and a pair of registration rollers is fed by the transport roller pair 21. 22 is conveyed. Next, the transfer paper is conveyed by the registration roller pair 22 in synchronization with the operation of the optical unit 40, and is conveyed to the gap between the photoconductor 31 and the transfer separation unit 34.
[0038]
Then, the toner image on the photoconductor 31 is transferred by the transfer separation unit 34, and then separated from the photoconductor 31 and conveyed to the fixing unit 23. The transfer paper is conveyed between the heating roller 23a and the pressure roller 23b rotating in the fixing unit 23, and the toner image transferred onto the transfer paper is transferred by the heat from the heat roller 23a and the pressure of the pressure roller 23b. The paper is melted and fixed on paper, discharged by a discharge roller pair 25, and stacked on a discharge tray 24.
[0039]
FIG. 2 is a flowchart showing a procedure for shifting to the power saving mode.
[0040]
First, a timer count is started (step S100), and then it is determined whether any operation key of the operation unit 50 is operated (step S110). If any operation key is operated (in step S110). YES), the timer count is stopped and this routine is ended (step S115).
[0041]
On the other hand, if no operation key is operated (NO in step S110), it is determined whether or not a predetermined time has elapsed (step S120). If the predetermined time has not elapsed (NO in step S120), step S110 is determined. Returning to the step, the determination of the presence / absence of the operation and the timer count are performed in parallel.
[0042]
Then, when a predetermined time elapses in a state where the operation keys are not operated (YES in step S120), the power saving mode is entered, the power supply to the heater 23c is stopped, and the display of the power saving mode display unit 61 is turned on. At the same time, the rotational speed of the cooling fan 26 is reduced from the first rotational speed V ₁ to the second rotational speed V ₂ (step S130).
[0043]
Subsequently, the temperature is detected by the temperature sensor 37 (step S140), and it is determined whether or not the current detected temperature is lower than the previous detected temperature (step S150). If the temperature has not decreased (NO in step S150), it is determined whether any operation key of the operation unit 50 is operated (step S160), and if any operation key is operated (in step S160). (YES), the routine returns from the power saving mode to the normal state and this routine is terminated (step S170).
[0044]
On the other hand, if any of the operation keys is not operated (NO in step S160), the process returns to step S140 and the temperature detection is repeated every predetermined sampling time, and when the detected temperature of this time is lowered with respect to the previously detected temperature ( If YES in step S150, the cooling fan 26 is stopped (step S180).
[0045]
As described above, since the cooling fan 26 is not stopped at the same time as the heater 23c at the time of shifting to the power saving mode, the temperature rise of the fixing unit 23 and peripheral members can be suppressed, and the temperature rise of the fixing unit 23 can be suppressed. Thus, it is possible to reliably prevent the peripheral members from being adversely affected. In addition, after the transition to the power saving mode, the rotation speed of the cooling fan 26 is reduced from the first rotation speed V ₁ to the second rotation speed V ₂ , so that power consumption can be reduced. Moreover, since the temperature in the apparatus main body 1 is detected and the rotation of the cooling fan 26 is stopped after the temperature shows a tendency to decrease, further power saving can be achieved.
[0046]
In the power saving mode, the controller 4 may heat the heater 23c to a temperature level lower than the fixing temperature. In this case, the return time to the fixing temperature can be shortened when the operation key is operated.
[0047]
Further, as the temperature sensor 37, a temperature sensor for controlling the toner density of the developing unit 33 may be used.
[0048]
Further, in the above embodiment, the fan 26 is stopped after the detected temperature tends to decrease in the power saving mode. However, the present invention is not limited to this, and when the detected temperature tends to be flat, or The fan 26 may be stopped when the rate of increase in the detected temperature becomes moderate.
[0049]
【The invention's effect】
As described above, according to the first aspect of the present invention, when an instruction for image formation is not performed continuously for a predetermined time, the mode is shifted to the power saving mode, and the heating operation to the fixing temperature by the heater is stopped. The driving of the cooling means is stopped with a delay from the transition to the power saving mode. Thus, power saving can be achieved by stopping the heating operation of the heater in the power saving mode, and an adverse effect due to a temperature rise of the fixing unit can be prevented. In addition, since other operations can be performed during the time until the fixing unit returns to the fixing temperature, workability can be improved.
[0050]
In addition, if the temperature in the main body of the device is detected and the previous detected temperature and the current detected temperature show a tendency to be flat after shifting to the power saving mode, the cooling unit stops driving, so that the temperature of the fixing unit is prevented from rising. The power consumption can be further reduced.
[0051]
According to the second and third aspects of the present invention, when the temperature in the apparatus main body is detected and the rate of temperature increase between the previous detected temperature and the current detected temperature becomes moderate after the shift to the power saving mode, the cooling means is driven. Therefore, power consumption can be further reduced.
[0052]
According to the invention of claim 4, when there is an instruction to execute image formation after shifting to the power saving mode, the start of the copying operation is waited until the fixing unit returns to the fixing temperature, Since the copying operation is started when the fixing temperature is restored, it is possible to reliably prevent the occurrence of copying failure. In addition, since other operations can be performed during the time until the fixing unit returns to the fixing temperature, workability can be improved.
[0053]
According to the invention of claim 5 , since the cooling capacity of the cooling means is reduced from the first cooling capacity to the second cooling capacity when the power saving mode is entered, the power consumption for driving the cooling means is reduced. can do.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a control configuration of an embodiment of an image forming apparatus to which the present invention is applied.
FIG. 2 is a flowchart showing an operation procedure in a power saving mode.
FIG. 3 is a front view showing an internal configuration of the embodiment.
[Explanation of symbols]
4 Control section (mode control means, stop control means, cooling control means, discrimination means, image formation control means)
DESCRIPTION OF SYMBOLS 10 Paper feed part 20 Paper conveyance part 23 Fixing part 23c Heater 26 Cooling fan (cooling means)
30 Image forming section 37 Temperature sensor (temperature detection means)
40 Optical unit 50 Operation unit 60 Display unit 61 Power saving mode display unit

Claims (5)

An image forming apparatus comprising: a fixing unit that fixes a transfer toner image onto transfer paper by heat of a heater heated to a fixing temperature; and a cooling unit that is driven by a first cooling capacity and discharges heat around the fixing unit. In
Mode control means for shifting to a power saving mode for stopping the heating operation of the heater to the fixing temperature when an instruction for image formation is not performed for a predetermined period of time;
Stop control means for stopping the driving of the cooling means delayed from the time of transition to the power saving mode;
Temperature detecting means for detecting the temperature in the apparatus body;
A discriminating means for discriminating whether or not the previous detected temperature by the temperature detecting means and the current detected temperature showed a flat tendency after the transition to the power saving mode;
The power-saving device of the image forming apparatus, wherein the stop control means stops the driving of the cooling means when the determining means determines that the previous detected temperature and the current detected temperature tend to be flat . An image forming apparatus comprising: a fixing unit that fixes a transfer toner image onto transfer paper by heat of a heater heated to a fixing temperature; and a cooling unit that is driven by a first cooling capacity and discharges heat around the fixing unit. In
  Mode control means for shifting to a power saving mode for stopping the heating operation of the heater to the fixing temperature when an instruction for image formation is not performed for a predetermined period of time;
  Stop control means for stopping the driving of the cooling means delayed from the time of transition to the power saving mode;
  Temperature detecting means for detecting the temperature in the apparatus body;
  After the transition to the power saving mode, a determination means for determining whether the temperature detection rate of the previous detection temperature and the current detection temperature by the temperature detection means is moderate,
  The power-saving device of the image forming apparatus that stops the driving of the cooling unit when the determining unit determines that the rate of temperature increase between the previously detected temperature and the current detected temperature is moderate. The determination means determines whether or not the temperature increase rate of the previous detection temperature and the current detection temperature by the temperature detection means is moderate after the transition to the power saving mode.
2. The image forming apparatus according to claim 1 , wherein the stop control unit stops driving the cooling unit when the determination unit determines that the rate of temperature increase between the previous detected temperature and the current detected temperature is moderate. Electrical equipment. If there is an instruction to execute image formation after the transition to the power saving mode, the copying unit waits until the fixing unit returns to the fixing temperature, and the copying operation is performed when the fixing temperature is recovered. 4. The power saving apparatus for an image forming apparatus according to claim 1, further comprising an image forming control unit to be started. After the transition to the Power Saving Mode the cooling capacity of the cooling means according to any one of 請 Motomeko 1 to claim 4 including a cooling control means for decreasing the lower second cooling capacity than the first cooling capacity Power saving device for image forming apparatus.

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