JP2001117452A - Method for preventing photoreceptor from adsorbing water and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for preventing a photoreceptor from absorbing water and an image forming device capable of providing an image of satisfactory picture by eliminating generating of image flowing and preventing degradation in the performance of the photoreceptor. SOLUTION: This method for preventing the photoreceptor from adsorbing water for an image forming device, which has a heater provided on the inner peripheral surface of the photoreceptor, a temperature detecting means for detecting the temperature of the photoreceptor, a control means for controlling the temperature of the photoreceptor by driving the heater based on detected information, an exposing optical system for forming an electrostatic latent image on the photoreceptor and a developing means for obtaining a sensible image by developing the electrostatic latent image, is provided with an image forming mode for forming an image and a standby mode F4 being in the state of waiting without forming an image. The control means controls the temperature of the photoreceptor at a first controlling temperature in the image forming mode and controls it at plural controlling temperature including the first controlling temperature F19 in the standby mode to prevent water from being adsorbed to the surface of the photoreceptor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing water from adsorbing on the surface of a photoreceptor in an image forming apparatus and an image forming apparatus such as a copying machine, a printer, a facsimile, and the like.

[0002]

2. Description of the Related Art In a photoreceptor used in an image forming apparatus, water tends to be adsorbed on the surface of the photoreceptor due to a phenomenon such as dew condensation under a high humidity environment. Is formed, the components of the toner, talc of paper, and the like are easily attached to the surface of the photoreceptor, and as a result, the surface resistance is reduced and the surface charges are easily moved, so that the latent image is disturbed and a so-called image flow is generated. An image defect occurs.

Further, the surface potential of the photoreceptor easily changes depending on environmental conditions, and it is difficult to obtain a stable quality image due to changes in environmental conditions.

For this reason, conventionally, by heating a photosensitive member, adsorption of water and a change in temperature are prevented to stabilize a surface potential, thereby obtaining a stable quality image.

For example, Japanese Patent Application Laid-Open No. 57-109003 discloses a method in which a heating setting temperature of a photosensitive member is controlled in accordance with an environmental temperature to maintain the photosensitive member in a state having the best sensitivity. Techniques for obtaining images of stable quality even under environmental conditions have been disclosed.

Japanese Patent Application Laid-Open No. 1-120573 discloses an image forming apparatus capable of performing a printing operation after heating a photosensitive member to a steady temperature at which a good image is obtained at the start of a printing operation at the time of turning on a power supply. If the temperature of the photoconductor before operation is equal to or lower than the reference temperature, the photoconductor is heated to a first temperature level T2 equal to or higher than the reference temperature for a predetermined time if the temperature of the photoconductor before operation is equal to or lower than the reference temperature. Then, the printing operation is enabled by heating to a second temperature level T1 lower than T2 and higher than the reference temperature, and if the temperature of the photoconductor is equal to or higher than the reference temperature, the photosensitive member is immediately heated to the second temperature level T1 by the heating means. There is disclosed a technology that enables a printing operation and thereafter heats and maintains the second temperature level T1 until the power is turned off.

[0007]

In the above two techniques, since the photoconductor is heated so as to always maintain a high temperature even in a standby state, an organic photoconductor using an organic photosensitive compound ( OPC) has a problem that thermal deterioration is liable to occur, and durability is impaired due to performance deterioration such as reduction in sensitivity of the photoreceptor. Further, thermal damage is caused to the cleaning blade which is always in contact with the photoconductor, thereby deteriorating the durability of the blade, and the developer in the developing device which is in contact with the photoconductor is heated and easily fused, so that the developer is There is a problem that deterioration due to fusion between the components is likely to occur and durability is impaired.

Further, in the latter technique, since heating to a high temperature is performed once before operation, a waiting time until the start of image formation is required, which is inefficient.

The present invention solves the above-mentioned problems,
Eliminates the occurrence of image deletion caused by adsorbed water, prevents deterioration of photoreceptor performance, does not cause thermal damage to the cleaning blade, does not cause deterioration of the developer, does not require waiting time, and is good It is an object of the present invention to provide a method for preventing water from adsorbing on a photoreceptor and an image forming apparatus capable of providing an image of high quality.

[0010]

It is an object of the present invention to provide (1) a photoconductor for forming an electrostatic latent image, a heating element provided on an inner peripheral surface of the photoconductor, and a temperature of the photoconductor. Temperature control means for detecting the temperature of the photoconductor, control means for controlling the temperature of the photoconductor by driving the heating element based on the detection information detected by the temperature detection means, and forming an electrostatic latent image on the photoconductor A method for preventing water from adsorbing on a photosensitive member in an image forming apparatus, comprising: an exposure optical system that performs exposure, and a developing unit that develops the electrostatic latent image to obtain a visible image. A standby mode in which the apparatus is in a standby state without performing the operation, the control unit controls the temperature of the photoconductor at a first control temperature in the image forming mode, and the control unit controls the temperature of the photoconductor in the standby mode. Control at multiple control temperatures including one control temperature A method for preventing water adsorbed on the photoreceptor to prevent water adsorbed on the surface of the photoreceptor, and
(2) A photoreceptor for forming an electrostatic latent image, a heating element provided on an inner peripheral surface of the photoreceptor, a temperature detecting unit for detecting a temperature of the photoreceptor, and a detection detected by the temperature detecting unit Control means for controlling the temperature of the photoreceptor by driving the heating element based on information; an exposure optical system for forming an electrostatic latent image on the photoreceptor; In the image forming apparatus having a developing unit for obtaining an image, an image forming mode for forming an image, and a standby mode in which the image forming is not performed and the image forming apparatus is in a standby state are provided. This is achieved by an image forming apparatus that controls the temperature of the photoconductor at one control temperature and controls the temperature of the photoconductor at a plurality of control temperatures including the first control temperature in the standby mode.

[0011]

The basic idea is that heating is performed to prevent water from adsorbing to the surface of the photoreceptor under high humidity environmental conditions, but the deterioration of the photosensitive compound is prevented without excessively heating the photoreceptor. Thus, unnecessary heating is eliminated. That is, in the present invention, instead of keeping the photoconductor in a constantly heated state in order to prevent water from adsorbing to the photoconductor, the temperature of the photoconductor is reduced to a low temperature in a standby state in which image formation is not performed. While maintaining the temperature, the photoconductor is intermittently heated to prevent water adsorption. Accordingly, it is possible to prevent the adsorption of water to the photoreceptor without excessively heating the photoreceptor, to eliminate the image flow, and to prevent the durability of the photoreceptor, the cleaning blade, and the developer from being impaired. it can. Further, since water adsorbed on the surface of the photoreceptor can be always prevented, image formation can be started immediately from the standby state, and no waiting time is required. Further, in the standby state, power is saved because the photoconductor is maintained at a low temperature.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an image forming apparatus applied to the present invention will be described with reference to the schematic diagram of FIG.

The image forming apparatus shown in FIG. 1 is an image forming apparatus of a digital system, and includes an image reading section A, an image processing section B (not shown), an image forming section C, and transfer paper transfer as transfer paper transfer means. It is composed of a section D.

An automatic document feeder for automatically conveying a document is provided above the image reading section A.
The original placed on the original 1 is moved by the original transport roller 12 to the original
The sheets are separated and conveyed, and the image is read at the reading position 13a. The document for which the reading of the document has been completed is discharged onto the document discharge tray 14 by the document conveying roller 12.

On the other hand, the image of the original placed on the platen glass 13 is read in the form of a V-shape by a reading operation at a speed v of a first mirror unit 15 comprising an illumination lamp and a first mirror constituting a scanning optical system. Reading is performed by moving the second mirror unit 16 including the second mirror and the third mirror located at the speed v / 2 in the same direction.

The read image is formed on a light receiving surface of an image sensor CCD as a line sensor through a projection lens 17. The line-shaped optical image formed on the image sensor CCD is sequentially photoelectrically converted into an electric signal (brightness signal), and then A
After performing / D conversion and performing processing such as density conversion and filter processing in the image processing unit B, the image data is temporarily stored in the memory.

In the image forming section C, a drum-shaped photosensitive member 21 serving as an image carrier and a charger 22 serving as charging means, a developing device 23 serving as developing means, and a transfer means are provided as image forming units. A transfer unit 24, a separator 25 as a separating unit, a cleaning unit 26, and a PCL (precharge lamp) 27 are arranged in the order of operation. The photoreceptor 21 is formed by applying a photoconductive compound on a drum substrate. For example, an organic photoreceptor (OPC) is preferably used, and is driven to rotate clockwise in the drawing.

After the rotating photoconductor 21 is uniformly charged by the charger 22, the exposure optical system 30 performs image exposure based on the image signal called from the memory of the image processing unit B. The exposure optical system 30 serving as a writing unit uses a laser diode (not shown) as a light emitting light source, passes through a rotating polygon mirror 31, an fθ lens (no symbol), and a cylindrical lens (no symbol) to bend an optical path by a reflection mirror 32, thereby performing main scanning. The photoreceptor 21
Is subjected to image exposure at the position Ao,
A latent image is formed by one rotation (sub-scan). In one example of the present embodiment, a character portion is exposed to form a latent image.

The latent image on the photoreceptor 21 is subjected to reversal development by the developing device 23, and a visible toner image is formed on the surface of the photoreceptor 21. In the transfer paper transport section D, paper feed units 41 (A) and 41 serving as transfer paper storage means in which transfer papers P of different sizes are stored below the image forming unit.
(B) and 41 (C) are provided, and a manual paper feed unit 42 for performing manual paper feed is provided on the side, and the transfer paper P selected from any of them is supplied to a guide roller 43.
The transfer paper P is fed along the transport path 40, and the transfer paper P is temporarily stopped and then re-fed by a pair of registration rollers 44 for correcting the inclination and deviation of the fed transfer paper.
The toner image on the photoconductor 21 is transferred to the transfer paper P by the transfer device 24 at the transfer position Bo, being guided by the transport path 40, the pre-transfer roller 43a, and the transfer entry guide plate 46,
Next, the charge is removed by the separator 25, and the transfer paper P is separated from the surface of the photoconductor 21, and is conveyed to the fixing device 50 by the conveying device 45.

The fixing device 50 has a fixing roller 51 and a pressure roller 52. By passing the transfer paper P between the fixing roller 51 and the pressure roller 52, the transfer paper P removes toner by heating and pressing. Weld. The transfer paper P on which the toner image has been fixed is discharged onto the discharge tray 64.

Next, a mode applied to the image forming apparatus according to the present invention will be described.

The mode management is performed by a mode management section 81 provided in the control means 80 as shown in FIG. The mode is selected and set in the mode management unit, and the operation of the image forming apparatus is executed according to the set mode.

The mode of the image forming apparatus according to the present invention includes a warm-up mode, an image forming mode, and a standby mode, and any one of the modes is selected and set. The warm-up mode is a mode in which an operation is performed from when the power of the main body of the image forming apparatus is turned on until image formation becomes possible. The image forming mode is a mode in which a series of image forming processes are executed for image forming by inputting an image forming start button, and operations are performed until the process is completed.
The standby mode is a mode other than the warm-up mode and the image forming mode, and is a mode in which the image forming is not performed after the warm-up is completed and the apparatus is on standby for image forming.

The mode management control executed by the mode management section 81 will be described with reference to the flowchart of FIG. When the mode management unit 81 detects that the power is turned on (F1), the warm-up mode is selected and set to execute the warm-up (F1).
2). When the warm-up mode is set, the control unit 80 controls each unit to execute a series of warm-up operations. The warm-up operation includes a series of process adjustment steps, and specifically includes fixing unit temperature adjustment, laser power adjustment, image density adjustment, photoconductor temperature adjustment, and the like. . When it is detected that all the adjustment steps of the series of processes have been completed, the warm-up is completed (F3), the warm-up mode is cleared, and the next standby mode is set (F3).
4). In the standby mode, a display is performed on the display operation unit of the image forming apparatus to notify the user that image formation is possible (F5). In the standby mode, the process waits until the image formation start button provided on the display operation unit is turned on (F6). When the image formation start button is turned on, the standby mode is cleared and the image formation mode is set (F7). As a result, a series of image forming operations are executed under the control of the control means 80, and the image forming is completed (F
8), the process returns to the standby mode again (F4). The above is the flow executed by the mode management unit 81.

Next, the structure of the temperature control of the photosensitive member according to the present invention will be described.

FIG. 2 is a front view showing the structure of the photosensitive member and its periphery in the image forming apparatus of the present invention. In FIG. 2, reference numeral 21 denotes a photoconductor, 71 denotes a heater serving as a heating element provided on an inner peripheral surface for heating the photoconductor 21, and 72 denotes a photoconductor temperature provided in contact with or near the outer periphery of the photoconductor. Is a temperature sensor as temperature detecting means for detecting the temperature.

As shown in FIG. 1, the image forming apparatus of the present invention has an environmental condition detecting means 73 for detecting the environmental condition of the environment in which the image forming apparatus is installed.
Is provided. The environmental condition detecting means 73 includes a temperature sensor 731 for detecting the temperature of the environment, and a humidity sensor 732 for detecting the humidity of the environment.

FIG. 3 is a configuration diagram for temperature control according to the present invention. The temperature information detected by the environmental condition detecting means 73 including the temperature sensor 72 and the temperature sensor 731 and the humidity sensor 732 and the environmental information including the environmental temperature and the environmental humidity are inputted to the control means 80. Controls the heater 71 via a power supply circuit 70 as a driving means based on the information to control the temperature of the photoconductor.

In the temperature control of the photosensitive member of the present invention, a plurality of different control temperatures are applied depending on the mode.

It is preferable to apply a plurality of control temperatures according to the environmental conditions.

Table 1 shows a first control temperature table of the photoconductors classified according to environmental conditions.

Here, the control temperature means a set temperature for controlling the photosensitive member to be maintained at a predetermined temperature. The temperature of the photoconductor is controlled by the control unit 80 with the control temperature as a target. The first control temperatures shown in Table 1 are provided with a plurality of different first control temperatures depending on environmental conditions. This is because the higher the first control temperature is, the higher the humid environmental condition in which the water is likely to be adsorbed, the higher the first control temperature can be. By doing so, thermal deterioration of the photoconductor, the developer, and the cleaning blade can be suppressed. Specifically, the first control temperature is set to 35 ° C. under relatively medium temperature and high humidity environment conditions, the first control temperature is set to 40 ° C. under high temperature and high humidity environment conditions, and other environmental conditions are set. Below, the first control temperature is 30 ° C. In addition, in the classification of the environmental conditions shown in Table 1, the temperature is divided into a low temperature of less than 17 ° C, a normal temperature of less than 17 to 22 ° C, a medium temperature of less than 22 to 27 ° C, and a high temperature of 27 ° C or more. Low humidity below 35% RH, 35
A table of the control temperature to be applied is formed by classifying environmental conditions into matrices of less than 65% RH and normal humidity and classifying 65% RH or more into high humidity, and classifying environmental conditions by a matrix based on the temperature and the humidity.

[0033]

[Table 1]

Table 2 shows a second control temperature table of the photoconductor classified according to the environmental conditions.

The second control temperature is used together with the first control temperature in a predetermined mode, and a different control temperature is applied in accordance with the environmental conditions similarly to the first control temperature. . The predetermined modes are a warm-up mode and a standby mode. In the warm-up mode, the second control temperature is applied to remove water adsorbed on the surface of the photoconductor due to the influence of environmental conditions. Therefore, different second control temperatures are provided depending on the environmental conditions, and are changed to the second control temperatures depending on the environmental conditions. In the standby mode, water is adsorbed on the photoreceptor surface when exposed to high-humidity environmental conditions, and is used to remove the adsorbed water every predetermined time. The purpose is to maintain the performance of the photoreceptor so that formation can be provided.

[0036]

[Table 2]

The above-described temperature control of the photosensitive member will be specifically described with reference to a flowchart of the temperature control.

FIG. 5 is a flow chart showing the flow of the temperature control of the photosensitive member in the warm-up mode.

When the mode management unit 81 detects that the power is turned on (F1), a warm-up mode is selected and set to execute warm-up (F2). When the warm-up mode is set, the control unit 80 controls the temperature of the photoconductor. First, the environmental condition detecting means 73 is controlled so as to detect the environmental temperature and humidity at the time of power-on (F9). The detected environmental temperature information and humidity information are input to the control means 80, and based on the environmental information, the first control temperature is selected from the table of Table 1 and the second control temperature is selected from the table of Table 2. Then, the first control temperature and the second control temperature applied in the warm-up mode are set (F10). Hereinafter, in each mode, it is preferable to apply the first control temperature and the second control temperature set when the power is turned on, in order to simplify the control. The execution of the temperature control of the photoconductor is started with the set first control temperature and the second control temperature (F11). First, the heater 71 is turned on so that the photoconductor is at the second control temperature, and temperature control is performed so that the photoconductor is heated (F12). When it is detected that the temperature of the photoconductor has reached the second control temperature due to the heating (F13), the process is continued at the second control temperature for a predetermined time of 2 minutes, and the lapse of 2 minutes is detected (F14). ), The control temperature is switched to the first control temperature (F15) to lower the temperature of the photoconductor.
It is detected that the temperature has decreased to the first control temperature (F1).
6), the warm-up of the photoconductor is completed (F17),
The temperature control of the photoconductor in the warm-up mode ends.

Next, the photoconductor temperature control in the standby mode will be described with reference to the flowchart of FIG. The standby mode is set in the mode management unit 81 (F4).
Then, the execution of the temperature control of the photoconductor in the standby mode is started (F18). In the temperature control of the photoconductor in the standby mode,
A predetermined time, for example, 30 minutes is set by the timer (F
20) After 30 minutes have passed (F21), the temperature is switched to the second control temperature (F22), and the photoconductor is heated at the second control temperature. By this heating, the adsorbed water on the photoreceptor surface is completely removed. When the second control temperature is continued for a predetermined time, for example, two minutes, and the lapse of two minutes is detected (F23),
The control temperature is switched to the first control temperature (F24). Thereafter, the flow from (F18) to (F24) is repeated. After the flow of (F18), it is determined whether or not the environment condition is high and the first control temperature and the second control temperature are equal to each other. A flow (F19) of performing the temperature control at the first control temperature without changing the control temperature from the first control temperature may be provided.

If the start button for image formation is turned on during the temperature control of the photosensitive member in the standby mode, the temperature control of the photosensitive member in the standby mode is cleared and the image shown in FIG. The flow of the temperature control of the photoconductor in the formation mode is executed. In the flow of the temperature control of the photoconductor in the image forming mode, when the start button is detected to be on by the mode management unit 81 (F6), the image forming mode is set (F7), and the control unit 80 executes the image forming mode. The temperature control of the photoconductor in the mode is executed (F25). In the temperature control of the photoconductor in the image forming mode, the temperature of the photoconductor is controlled at the first control temperature (F26). When the image formation is completed (F8), the temperature control of the photoconductor in the image formation mode is cleared, and the process returns to the standby mode of FIG. 6 (F4).

FIG. 8 shows the first condition under high humidity environmental conditions.
4 shows a time chart that is changed at a predetermined cycle at predetermined time intervals at the control temperature and the second control temperature. In this embodiment, it was confirmed that by performing heating for 30 minutes every 2 minutes, water adsorbed on the photoconductor can be prevented.

Further, in the above-described embodiment of the present invention, the environmental temperature information is detected and obtained by the dedicated temperature sensor 731 of the environmental condition detecting means 73. However, the temperature sensor 731 is removed and the environmental temperature information is obtained. When the temperature information is obtained from the temperature sensor 72 as the temperature detecting means of the photoconductor, the same effect is recognized, and the temperature sensor 72 of the temperature detecting means of the photoconductor is also used as the temperature sensor of the environmental condition detecting means. It has been found that the number of parts can be reduced and the cost can be reduced accordingly.

[0044]

According to the present invention, even under a high humidity environment, by heating the photoreceptor, adsorption of water on the photoreceptor surface can be prevented, and the occurrence of image deletion can be eliminated.

Since the photosensitive member is always kept in a heated state in order to prevent water from adsorbing to the photosensitive member and the photosensitive member is not excessively heated, deterioration of the photosensitive compound of the photosensitive member, a cleaning blade, Thermal degradation of the developer can be eliminated, and the loss of durability can be eliminated.

In the standby state where image formation is not performed, the photosensitive member is intermittently heated to prevent water adsorption while maintaining the temperature of the photosensitive member at a low temperature. Thus, the image formation can be started immediately from the standby state, and the waiting time is not required.

Further, in the standby state, power is saved because the photosensitive member is maintained at a low temperature.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating an overall configuration of an image forming apparatus of the present invention.

FIG. 2 is a front view showing a configuration of a photosensitive member and its periphery in the image forming apparatus of the present invention.

FIG. 3 is a configuration diagram for temperature control.

FIG. 4 is a flowchart of mode management control.

FIG. 5 is a flowchart of temperature control of a photoconductor in a warm-up mode.

FIG. 6 is a flowchart of temperature control of a photoconductor in a standby mode.

FIG. 7 is a flowchart of temperature control of a photoconductor in an image forming mode.

FIG. 8 is a time chart showing switching of a control temperature.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 21 Photoconductor 22 Charger 23 Developing device 24 Transfer device 25 Separator 26 Cleaning means 26A Cleaning blade 27 PCL (precharge lamp) 30 Exposure optical system 70 Current supply circuit 71 Heater 72 Temperature sensor 73 Environmental condition detecting means 731 Temperature sensor 732 Humidity Sensor 80 Control means 81 Mode management unit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H027 DA13 EA13 EF01 EF09 EF15 JA12 2H035 CA07 CB01 CZ03 9A001 BB06 HH23 KK42

Claims (11)

[Claims] 1. A photoreceptor for forming an electrostatic latent image, a heating element provided on an inner peripheral surface of the photoreceptor, a temperature detector for detecting a temperature of the photoreceptor, and a temperature detected by the temperature detector. Control means for controlling the temperature of the photoconductor by driving the heating element based on the detected information, an exposure optical system for forming an electrostatic latent image on the photoconductor, and developing the electrostatic latent image. A method for preventing adsorbed water of a photoreceptor in an image forming apparatus having a developing unit for obtaining a visible image, wherein an image forming mode for forming an image and a standby mode in which the image forming apparatus is on standby without performing image forming are provided. The control unit controls the temperature of the photoconductor at a first control temperature in the image forming mode,
In the standby mode, a method for preventing water adsorbed on the surface of the photoreceptor by controlling at a plurality of control temperatures including the first control temperature to prevent water adsorbed on the surface of the photoreceptor. 2. The method according to claim 1, wherein the plurality of control temperatures are at least a first temperature.
2. The method according to claim 1, wherein the control temperature comprises a first control temperature and a second control temperature higher than the first control temperature. 3. The method according to claim 1, wherein the first control temperature and the second control temperature are changed every predetermined time.
3. The method according to claim 2, wherein switching of the control temperature is repeated. 4. An apparatus according to claim 1, further comprising an environmental condition detecting means for detecting an environmental condition, wherein the control temperature in said standby mode is changed based on environmental information detected by said environmental condition detecting means. A method to prevent water from adsorbing on the photoconductor. 5. The method according to claim 4, wherein the environmental condition is an environmental condition at the time of power-on. 6. A photoreceptor for forming an electrostatic latent image, a heating element provided on an inner peripheral surface of the photoreceptor, temperature detecting means for detecting a temperature of the photoreceptor, and a temperature detected by the temperature detecting means. Control means for controlling the temperature of the photoconductor by driving the heating element based on the detected information, an exposure optical system for forming an electrostatic latent image on the photoconductor, and developing the electrostatic latent image. In an image forming apparatus having a developing unit that obtains a visible image, an image forming mode for forming an image, and a standby mode in which the image forming apparatus is on standby without performing image forming are provided.
Controlling the temperature of the photoconductor at a first control temperature in the image forming mode, and controlling the temperature of the photoconductor at a plurality of control temperatures including the first control temperature in the standby mode. Characteristic image forming apparatus. 7. The method according to claim 1, wherein the plurality of control temperatures are at least first.
7. The image forming apparatus according to claim 6, wherein the control temperature is higher than the first control temperature and the second control temperature is higher than the first control temperature. 8. The method according to claim 1, wherein the first control temperature and the second control temperature are changed every predetermined time.
8. The image forming apparatus according to claim 7, wherein switching of the control temperature is repeated. 9. The control mode according to claim 6, further comprising an environmental condition detecting means for detecting an environmental condition, wherein the control temperature in the standby mode is changed based on the environmental information detected by the environmental condition detecting means. Image forming device. 10. The image forming apparatus according to claim 9, wherein said environmental condition is an environmental condition at the time of power-on. 11. The image forming apparatus according to claim 9, wherein said environmental condition detecting means is also used as said temperature detecting means.