JP6462261B2 - Image forming apparatus and image forming system - Google Patents

Description

  The present invention relates to an image forming apparatus for forming an image on a recording material by image forming process means such as an electrophotographic system.

  Since an image forming apparatus such as an electrophotographic system is used all over the world, an appropriate image must be formed on a recording material even under various environments such as high temperature and high humidity and low temperature and low humidity. Therefore, an environment detection sensor capable of detecting temperature and humidity is provided in the image forming apparatus, and various types of image formation control are performed based on information on the temperature or humidity detected by the environment detection sensor (Patent Document 1). 2).

  Specifically, when the image forming apparatus is used in a high temperature and high humidity environment such as an air temperature of 30 ° C. and a humidity of 80%, the fixing temperature adjustment temperature during printing is controlled in order to prevent paper curling and retransfer. In some cases, control is performed such that the transfer bias is lowered. Further, when the image forming apparatus is used in a low temperature and low humidity environment such as an air temperature of 15 ° C. and a humidity of 10%, the fixing temperature adjustment temperature during printing is increased in order to prevent deterioration of fixing property and transfer omission. Control such as increasing the transfer bias is performed.

JP 2006-171247 A Japanese Patent Laid-Open No. 11-184265

  However, there are cases where it is not possible to deal with the usage status of the user by dealing with only the environment detection sensor in the image forming apparatus. For example, in the middle of winter in Russia, it is normal for the temperature to fall below 0 ° C. The next morning, when a user who comes to work uses a heating device such as an air conditioner in a room where a copying machine, which is an image forming device, is installed, the detection temperature of the environmental detection sensor with a small heat capacity rises quickly due to the characteristics. Thus, a photosensitive drum or a fixing device having a large heat capacity may remain at a low temperature.

  In such a case, the temperature detected by the environment detection sensor may be 20 ° C., and the temperature of the photosensitive drum, the developing device, the conveyance path, and the fixing device may be 0 ° C. When the user turns on the power of the copying machine in such a state, the image forming apparatus performs normal warm-up control based on the temperature of the environment detection sensor.

  However, various drive gears, motors, and the like may cause problems such as gear breakage and motor damage due to an increase in rotational load when a normal drive operation is performed despite the extremely low temperature.

  Further, even if the failure does not occur, the high heat of the fixing heater of the fixing device is conducted to the conveying path and the photosensitive drum, which are still at a low temperature, so that condensation may occur and an image defect may be caused.

  On the other hand, in countries and regions where the temperature exceeds 40 ° C in midsummer, the indoor temperature may rise to close to 50 ° C. In that case, when a cooling device is used in the vicinity of the copying machine, the temperature of the environment detection sensor in the copying machine immediately drops, but there is a concern that paper, toner, etc. remain hot. For example, it is conceivable that the environment detection sensor detects 20 ° C. although the toner and paper are 45 ° C.

  The developing device sets an appropriate developing bias depending on the temperature in consideration of the fluidity of the toner. Therefore, when printing is performed in this state, normal temperature and humidity are controlled by the detection temperature of the environment detection sensor, so that image formation is performed ignoring the fluidity of the toner, and the image density does not become an appropriate density. There is a fear.

  In addition, the fixing device is also designed to reduce the temperature of the fixing in a high-temperature and high-humidity environment in order to cope with the curling of moisture-absorbing paper. The amount of curling of the subsequent paper becomes large, and there is a possibility that a paper passing jam or the like occurs in the conveyance path.

  In order to eliminate such a problem, measures such as increasing the heat capacity of the environment detection sensor in the image forming apparatus to make it less susceptible to the influence of surrounding air conditioning can be considered. However, in order to increase the thermal capacity of the environmental detection sensor, it is inevitable to add parts, increase the space, and increase the cost. In addition, if the thermal capacity is large, the environmental sensor can detect the temperature and humidity of the surrounding environment appropriately. The original function may be degraded.

As described above, there is a possibility that appropriate control according to the environment in which the image forming apparatus is placed cannot be performed only by the detection information of the environment detection sensor arranged inside the image forming apparatus .

In order to achieve this object, an image forming apparatus according to the present invention is an image forming apparatus that forms an image on a recording medium, and is disposed inside the image forming apparatus and detects environmental information inside the image forming apparatus. A detection unit; an environmental information acquisition unit that acquires environmental information measured outside the image forming apparatus; and the internal detection environment detected by the environmental information detection unit after the image forming apparatus is turned on. Based on information and acquired environment information acquired by the environmental information data measured a plurality of times outside in a predetermined time before turning on the power, acquired by the environment information acquiring means Control means for controlling conditions relating to image formation on a recording medium, and the conditions controlled by the control means include the detection environment information after the power is turned on and the conditions At least one of the detected environment information after turning on the power and the acquired environment information before turning on the power when both information of the acquired environment information before turning on the power is above a predetermined temperature The information is different when the temperature is lower than a predetermined temperature.

According to the present invention, appropriate control according to the environment in which the image forming apparatus is placed can be performed.

1 is a diagram illustrating a schematic configuration of a printer using a laser beam according to an embodiment of an image forming apparatus of the present invention. FIG. 2 is a cross-sectional view illustrating a configuration of a fixing device of the printer illustrated in FIG. 1. FIG. 2 is a block diagram illustrating a configuration of a central control device provided in the printer illustrated in FIG. 1 and a communication network connected to the printer. It is a block diagram which shows the structure of the control part shown in FIG. 2 is a flowchart showing details of an operation when the printer shown in FIG. 1 is started up. It is a flowchart which shows operation | movement of the ice melting mode of the printer shown in FIG. It is a table | surface which shows the effect of embodiment of this invention when compared with a prior art. FIG. 6 is a circuit diagram illustrating a configuration of an antenna electrode type toner remaining amount detection unit of a developing device in a printer according to another embodiment of the present invention. It is a flowchart which shows the conditions which transfer to ice melting mode in the printer of other embodiment of this invention. It is a flowchart which shows operation | movement of the ice melting mode in the printer of other embodiment of this invention. FIG. 10 is a diagram illustrating a water content of a paper, a heater control temperature, a curl amount, and a paper passing state in a printer according to still another embodiment of the present invention. 9 is a flowchart illustrating an operation of suppressing paper curling under high temperature and humidity in a printer according to still another embodiment of the present invention. 13 is a table showing that each mode is selected according to the temperature / humidity range detected by the environment sensor and the temperature / humidity range acquired from the external temperature / humidity database server 300 for the operation shown in FIG. 12. 10 is a table showing a heater control temperature, a transfer bias value, and a development bias voltage in a high-temperature and high-humidity mode, a semi-high temperature and high-humidity mode, and a normal control mode in a printer according to still another embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<First Embodiment>
(Entire printer configuration)
FIG. 1 is a diagram showing a schematic configuration of a printer using a laser beam according to an embodiment of an image forming apparatus of the present invention.

  The printer 100 includes a photosensitive drum 1 as an image carrier having a photoconductive layer such as OPC or a-Si. The photosensitive drum 1 is rotatably supported by the apparatus main body 101 of the printer 100, and is driven to rotate at a predetermined speed in the direction of arrow A by a main motor (not shown).

  A charging roller 2 for uniformly charging the photosensitive drum 1 is provided around the photosensitive drum 1. The cleaning brush 40 is pressed against the charging roller 2 with a predetermined pressure, and rotates by driving input from the charging roller 2 to clean the surface of the charging roller 2. The laser scanner 3 exposes the surface of the photosensitive drum 1 with a laser beam to form an electrostatic latent image. The developing device 4 supplies toner to the surface of the photosensitive drum 1 by the developing sleeve 4a, and visualizes the electrostatic latent image with the toner. The transfer roller 5 transfers the toner image formed on the photosensitive drum 1 to a sheet-like recording material P such as paper. The cleaning device 6 collects the untransferred toner remaining on the photosensitive drum 1 by the cleaning blade 6a.

  A paper feed cassette 7 containing a recording material P is provided below the apparatus main body 101, and a fixing device 8 is provided above the photosensitive drum 1. On the back surface of the apparatus main body 101, a control substrate 9 for controlling an image forming operation and the like, and a high-voltage substrate 10 for applying a high voltage to the charging roller 2, the developing device 4, and the like are arranged. The control board 9 is mounted with a CPU 9a for issuing a command for executing an image forming operation or the like, a CPU 9b for executing a temperature control for fixing, and a memory 9c storing a program or the like. The high-voltage substrate 10 has a charging application power source 10a for applying a voltage for charging to the charging roller 2, a development application power source 10b for applying a voltage for development to the developing sleeve 4a, and a transfer roller 5 for transferring the voltage. A transfer application power source 10c for applying a voltage for the purpose is provided. The operation of the printer is realized by the CPUs 9a and 9b of the control board 9 reading out necessary programs and data from the memory 9c and executing various controls.

  The fixing device 8 is provided with a cooling fan 13 for cooling components in the fixing device 8, and is controlled by the CPU 9b.

  The printer 100 is also provided with a central control device 201 that controls the overall operation of the printer 100. In addition, the printer 100 is provided with a transmission / reception device 204 (environment information acquisition means) so that communication can be performed between the network connected to the router 207 and the central control device 201.

(Configuration of fixing device)
FIG. 2 is a cross-sectional view showing the configuration of the fixing device 8. In this embodiment, an on-demand fixing device using an endless film is taken as an example, but a fixing device having another configuration can also be used.

  The fixing film 10 and the pressure roller 11 are pressurized by a pressure device (not shown) to form a fixing nip portion Nf. The pressure roller 11 is rotationally driven by a driving device (not shown), slides the fixing film 10, and conveys the recording material P in the direction of arrow B. The heater 12 is supported by a heater stay 15 and directly heats the fixing nip portion Nf. The temperature of the heater 12 is constantly monitored by a thermistor 14 (temperature detection means).

  For example, the control temperature of the heater 12 is determined based on the temperature data obtained from the thermistor 14 as follows. That is, when a print job is started, the detected temperature of the thermistor 14 at that time is read. If the detected temperature is 100 ° C. or higher, it is determined that the fixing device 8 is warmed immediately after the previous print job, and the heater Control is performed such that the control temperature of 12 is lowered by 5 ° C.

  The recording material P stored in the paper feed cassette 7 forms a toner image at the transfer nip Nt between the photosensitive drum 1 and the transfer roller 5, and the fixing film 10 and the pressure roller 11 A fixing process is performed at the fixing nip portion Nf. Thereafter, the recording material P is discharged out of the printer 100.

(Central controller and communication network configuration)
FIG. 3 is a block diagram illustrating a configuration of a central control device 201 provided in the printer 100 and a communication network connected to the printer 100.

  As shown in the figure, the central control device 201 includes a control unit 202 that controls the operation of each unit of the printer 100, an environment detection unit 205 that detects environmental information such as temperature and humidity, and the internal environment state of the printer 100. And an environment discrimination unit 203 for discriminating between. Further, the central control device 201 is provided with an abnormality detection unit 206 that detects whether or not the environment detection unit 205 has an abnormality.

  The router 207 is connected to an external network 208 such as the Internet and an internal intranet 209 such as a company.

  Furthermore, the external network 208 stores temperature / humidity data for each month, day, and hour in each database, and provides temperature / humidity data for a specific time zone on a specific month when accessed from the outside. A temperature / humidity database server 300 (transmitting means) that can (transmit) can be connected.

  Further, a timer 210 having a clock function is connected to the control unit 202 so that the time can be acquired. This timer can keep counting the date and time by the internal battery even when the printer 100 is turned off.

  When the power of the printer 100 is turned on, the temperature / humidity database server 300 is accessed from the control unit 202 via the environment determination unit 203, the transmission / reception device 204, the router 207, and the external network 208. Then, information indicating the area where the printer 100 is located and information indicating the date and time are transmitted, and temperature and humidity data corresponding to the area, date and time are acquired.

  The information indicating the area is allocated corresponding to the area when the user inputs the area from the operation panel or the like of the printer 100. It should be noted that a GPS (Global Positioning System) receiver may be built in, and GPS position information may be acquired from this receiver and sent. Alternatively, the temperature / humidity database server 300 may detect the position where the printer 100 is located based on the IP address of the Internet to which the printer 100 is connected.

  In the above description, the timer 100 is provided in the printer 100 so that the date and time are transmitted from the printer 100 to the temperature / humidity database server 300. However, only the information indicating the area is transmitted from the printer 100 side, the date and time are managed on the temperature and humidity database server 300 side, and the temperature and humidity data in a certain time zone from the date and time when the printer 100 was accessed. May be transmitted.

  On the other hand, the environment detection unit 205 is provided with an environment information detection sensor that detects the temperature and humidity inside the printer 100, and the temperature and humidity information detected by the environment information detection sensor is always sent to the environment determination unit 203. It is supposed to be sent.

  The environment determination unit 203 compares the temperature and humidity information in the printer 100 sent from the environment detection unit 205 with the temperature and humidity information sent from the temperature / humidity database server 300. And it is discriminate | determined whether the temperature and humidity detected by the environment information detection sensor of the environment detection part 205 are appropriate, and notifies the result to the control part 202. FIG. If it is determined to be appropriate, the control unit 202 shifts to a normal startup operation. If it is determined to be inappropriate, the control unit 202 determines an abnormal mode such as an ice melting mode. Migrate to

  In the above description, the temperature / humidity database server 300 is started up and a temperature / humidity database is constructed. However, temperature / humidity data for a certain period of time announced by reading data on a homepage that provides weather information and the like provided by a third party may be obtained.

  When a print command is issued from the computer 21 connected to the internal intranet 209, the print command is sent to the control unit 202 via the router 207, the transmission / reception device 204, and the like, and conditions for image formation are determined.

  The determination of the image forming condition is based on temperature and humidity data detected by the environment detection unit 205. For example, when the temperature is detected to be 30 ° C. and the humidity is 80%, the fixing bias is set to −500 V, the transfer bias is set to 2 kV, and the fixing temperature control is set to 160 ° C.

  The abnormality detection unit 206 always checks whether there is an abnormality in the environment detection unit 205. When the environment sensor of the environment detection unit 205 is disconnected, the detected voltage value becomes an abnormal value, so that it is determined that the environment detection device is out of order.

  The printer 100, the temperature / humidity database server 300, the external network 208, and the router 207 constitute an image forming system.

  FIG. 4 is a block diagram illustrating a configuration of the control unit 202. As shown in the figure, the control unit 202 includes a CPU 400 that executes a program, a ROM 401 that stores programs and data, and a RAM 402 that is used as a work area when the program is executed. And it is connected to other parts via the I / O interface 403.

(Operation when starting up the printer)
Next, details of the operation when starting up the printer 100 will be described.

  FIG. 5 is a flowchart showing details of the operation when the printer 100 is started up.

  As shown in the figure, for example, the user comes to work the next morning when the previous night was extremely low temperature, and the printer 100 is turned on (step S401). Then, the control unit 202 of the printer 100 accesses the temperature / humidity database server 300 and collects temperature data of the area where the printer 100 is installed for 6 hours (step S402). For example, if a printer installed in Misato City, Saitama Prefecture is turned on at 10 am, external temperature data from 4 am to 10 am in Misato City, Saitama Prefecture is acquired from the temperature / humidity database server 300. .

  When the average of the obtained temperature data for 6 hours is 0 ° C or higher, the temperature of the environment detection sensor is 0 ° C or higher (step S403), and the detected temperature of the thermistor 14 of the fixing device 8 is normal (step S404). Is in a normal state and shifts to a normal startup mode (step S405). On the other hand, if even one of the conditions in step S403 and step S404 is not satisfied, there is a possibility that part of the printer 100 is below freezing point. For this reason, it shifts to an ice melting mode (freezing disappearance means) for eliminating an abnormal state of freezing (disappearing freezing) (step S406).

(Ice melting mode operation)
FIG. 6 is a flowchart showing the operation in the ice melting mode.

  As shown in the figure, first, without turning the pressure roller 11, the energization ratio of the heater 12 is set to 50%, and after the temperature of the thermistor 14 reaches 100 ° C., the cooling fan 13 is rotated for 10 seconds. Wait (step S501). Thereby, the ice in the fixing nip portion Nf is melted.

  Next, the pressure roller 11 is rotated by the nip width (in this embodiment, about 5 mm) (step S502). The amount of rotation is ideally equal to the nip width, but in order to shorten the cooling time, the amount may be about 1.5 to 2 times the nip width of the fixing nip portion Nf. If the pressure roller 11 has not yet rotated one revolution (step S503), the cooling fan 13 is stopped, the heater is turned off, and the temperature drop of the thermistor 14 is confirmed (step S505).

  If the temperature drop of the thermistor 14 is 3 ° C. or more per second (step S506), the nip is regarded as frozen, and the cooling fan 13 is rotated and the heater control temperature 100 ° C. is waited for 5 seconds ( Step S507).

  On the other hand, if the temperature drop of the thermistor 14 is less than 3 ° C. per second (step S506), the nip is regarded as not frozen, and the process returns to step S502 without doing anything.

  The above steps are repeated, and if it is determined in step S503 that the pressure roller 11 has made one revolution, the ice melting mode is terminated (step S504).

  In this way, the ice sticking to the entire surface of the pressure roller 11 is melted by the control shown in FIG. In addition, by rotating the cooling fan 13 of the fixing device 8 while rotating the pressure roller 11 by the nip width, not only the ice in the nip portion in the fixing device 8 is melted but also the heat of the fixing device 8 inside the printer 100. Is circulated to increase the temperature of the photosensitive drum 1 and the conveying gear. The heater control temperature is set to 100 ° C., which is lower than the normal printing operation temperature (180 ° C.) because the high temperature heat is suddenly transmitted to other low temperature members and the inside of the printer is condensed. Is to prevent.

  As described above, the environment detection sensor indicates normal temperature even though the gear part and the fixing part are frozen. Damage to the fixing device and the photosensitive drum can be prevented.

  FIG. 7 is a table showing the effect of this embodiment compared to the prior art.

  As shown in the figure, in the conventional technology, when heating was performed near the printer body in a cryogenic environment (0 ° C) and paper was passed, jam occurred at a high rate (14/100). In the present embodiment, the ratio can be greatly reduced.

Second Embodiment
Next, a printer which is another embodiment of the image forming apparatus of the present invention will be described. Hereinafter, a different part from 1st Embodiment is demonstrated, about the part which is the same as that of 1st Embodiment, or a similar part, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

  In the first embodiment, not only the environment detection sensor of the environment detection unit 205 (environment information detection means) but also the thermistor 14 of the fixing device 8 determines whether to enter the ice melting mode or whether to exit from the ice melting mode. Was.

  However, when the thermistor 14 is also in contact with the outer periphery of the roller as in the case of roller fixing, it has a small heat capacity and is directly exposed to the outside. Therefore, the temperature is much higher than other members. Further, as in the belt fixing shown in the first embodiment, when the thermistor 14 is present inside the heater 12, the thermistor 14 is directly under the heater 12 and is surrounded by a member having a large heat capacity such as the heater stay 15. Therefore, the temperature is less likely to drop than the surrounding environment. For example, when a large amount of moisture-absorbing paper is poured and left in an extremely low temperature environment, the temperature of the thermistor 14 covered with many members is reduced by moisture absorption, although the gear part and the photosensitive drum 1 tend to freeze. Hard to fall.

  When the temperature detected by the thermistor 14 is significantly different from the temperature of other members such as the photosensitive drum 1 and the gear, there is a possibility that the temperature is not controlled at the temperature that should be controlled. Therefore, the accuracy of failure detection is improved when the temperature in the photosensitive drum 1 and the developing device 4 is also set as a criterion. However, it is inefficient in terms of cost, space, and the like to place temperature detection sensors at all locations that affect image formation, such as the photosensitive drum 1 and the developing device 4.

  Therefore, in this embodiment, an existing configuration is used for temperature detection instead of newly placing a temperature detection sensor. That is, for detecting the temperature in the developing device 4, an antenna electrode type toner remaining amount detecting device used for detecting the remaining amount of developer (toner) is used. Hereinafter, the antenna electrode type toner remaining amount detection unit will be described.

(Measurement of temperature in the developer container)
In such an image forming apparatus, the toner stored in the developing container is consumed every time an image forming operation is performed. Therefore, in the image forming apparatus, a toner remaining amount detection unit is provided in the developing container, detects that the remaining amount of toner in the developing container has decreased to a predetermined amount, and displays the necessity for the next toner replenishment. To inform the user. Such a toner remaining amount detection unit is configured by measuring an induced voltage between a developing sleeve provided inside a developing container and a rod-shaped antenna electrode arranged in parallel to the developing sleeve, and its dielectric. A configuration for detecting the remaining amount of toner in the developing container from the voltage is known.

  Here, the reason why the induced voltage generated between the developing sleeve and the antenna electrode changes according to the remaining amount of toner remaining in the developing container will be described.

  FIG. 8 is a circuit diagram illustrating a configuration of an antenna electrode type toner remaining amount detection unit of the developing device 4.

  As shown in the figure, an antenna electrode 4c is provided in the developing container 4b of the developing device 4, and an electrostatic capacity C2 is generated between the antenna electrode 4c and the developing sleeve 4a. A current flows from the AC power source AC through the capacitance C2 and the resistor R2, and the voltage of the antenna electrode 4c is measured as the antenna output. A differentiation circuit is configured by the capacitance C2 and the resistor R2.

  The voltage from the AC power supply AC can be measured from the reference output via a differentiation circuit composed of a capacitor C1 and a resistor R1 incorporated in the substrate.

  The output from the AC power supply AC has a rising voltage measured by a differentiating circuit including a capacitor C1 and a resistor R1, and a rising voltage measured by a differentiating circuit including a capacitance C2 and a resistor R2. These voltages are stabilized by a peak hold circuit (not shown) and output as a reference output and an antenna output.

  The value of the capacitance C2 varies depending on the distance between the developing sleeve 4a and the antenna electrode 4c, the dielectric constant of the substance existing between the developing sleeve 4a and the antenna electrode 4c, and the like.

  Since the developing sleeve 4a and the antenna electrode 4c are fixed to the developing container 4b, the distance between them (between the electrodes) does not change, but the developing sleeve 4a and the antenna electrode depend on the remaining amount of toner in the developing container 4b. The amount of toner existing in the space between 4c changes. For this reason, the voltage output from the antenna output changes according to the change in the amount of toner existing in the space between the developing sleeve 4a and the antenna electrode 4c.

  On the other hand, since the voltage from the reference output does not change according to the remaining amount of toner, the remaining amount of toner can be measured by measuring the voltage between the antenna output and the reference output shown in FIG. it can.

  By the way, in the present embodiment, the reference output has the following temperature dependence due to the temperature characteristics of the components of the resistor R1 and the capacitor C1 in FIG.

Reference voltage reading value = reference voltage set value−0.0013 × environment temperature + 0.0299
For example, when the set voltage value is 3.0V and the environmental temperature is 30 ° C., the reference voltage reading is 2.93V.

  Therefore, if the resistor R1 and the capacitor C1 are installed near the developing container 4b and the reference voltage is measured, the temperature near the developing container 4b can be predicted with a certain degree of accuracy.

(Measurement of temperature near the photosensitive drum)
It is desirable to measure the temperature in the vicinity of the photosensitive drum 1 at the same time when the temperature inside the developing device is detected by the toner remaining amount detection unit. An existing technique suitable for measuring the temperature around the photosensitive drum 1 is a transfer current control method called ATVC (Auto Transfer Voltage Control).

  In the contact transfer method, since the transfer roller 5 changes its characteristics due to environmental changes or the like, a measure is generally taken to appropriately control the transfer voltage applied to the transfer roller 5 in accordance with the change in the characteristics of the transfer roller 5. One of the applied transfer voltage control systems is an ATVC (automatic transfer voltage control) system.

  The ATVC controls the transfer bias applying means so that the current flowing through the transfer roller 5 becomes a preset constant current value Io at the timing when the transfer part is in a non-image area (non-sheet passing) (constant current mode). ), And the applied voltage Vto at this time is detected.

The transfer voltage Vt is determined based on the detected applied voltage Vto. For example,
Vt = a × Vto + b [kV]
The transfer voltage Vt is calculated using the following calculation formula.

  Then, the transfer voltage Vt calculated when the transfer portion is in the image region (when the paper is passed) is applied to the transfer roller 5 by constant voltage control to execute transfer of the toner image from the image carrier side to the recording medium side (constant voltage). mode).

  By determining the transfer voltage by such a method, the applied transfer voltage to the transfer roller 5 is appropriately controlled in accordance with the characteristic change of the material of the transfer roller 5 regardless of the characteristic change of the transfer roller 5 due to the environmental change or the like. Thus, it is possible to obtain good transferability at all times.

  Here, the timing when the transfer part is in the non-image area is the timing when the image carrier is not in the image area (= when paper is not passed) in the transfer part during “pre-rotation” or the transfer when “between paper” This is the timing at the time of the non-image area of the image carrier in the part (= when no paper is passed). Note that “during pre-rotation” refers to a period from when the driving of the printer 100 in the standby (standby) state is started based on the print start signal until the leading edge of the first recording material P reaches the transfer portion. Say. Also, “at the time of paper” refers to the interval between the trailing edge of the recording medium and the leading edge of the next recording medium in the continuous paper feed printing mode.

  By using such a transfer bias that changes due to environmental fluctuations, the temperature near the transfer roller including the photosensitive drum 1 can be predicted with a certain degree of accuracy.

  As described above, in addition to the thermistor of the first embodiment, the detection accuracy can be further increased by using the toner remaining amount detection unit and the ATVC in the developing container 4b.

  FIG. 9 is a flowchart showing the conditions for shifting to the ice melting mode when these two criteria are added.

  As shown in the figure, as in the first embodiment, the printer 100 is powered on (step S801). Then, the control unit 202 of the printer 100 accesses the temperature / humidity database server 300 and collects temperature data of the area where the printer 100 is installed for 6 hours (step S802).

  If the average of the acquired temperature data for 6 hours is 0 ° C or higher and the temperature of the environment detection sensor is 0 ° C or higher (step S803), is the detected temperature of the thermistor 14 of the fixing device 8 normal? It is checked whether or not (step S804). As described above, since the thermistor 14 itself may deviate from the ambient temperature, the detected voltage of the ATVC is confirmed even if the thermistor 14 is normal (step S805). If this value is equal to or greater than a threshold value (10 V in the present embodiment), it is finally checked whether or not it is equal to or less than a reference voltage value for detecting the remaining amount of toner (1.5 V in the present embodiment) (step S806). ). If all the values are normal in the confirmation of the values from step S803 to step S806, the normal startup mode is entered (step S807). If even one of these steps is not a normal value, there is a possibility that a part of the printer 100 is below the freezing point, so that the process proceeds to the ice melting mode (step S808).

  FIG. 10 is a flowchart showing the operation of the ice melting mode of the present embodiment.

  As shown in the figure, first, without turning the pressure roller 11, the energization ratio of the heater 12 is set to 50%, and after the temperature of the thermistor 14 reaches 100 ° C., the cooling fan 13 is rotated for 10 seconds. Wait (step S901). Thereby, the ice in the fixing nip portion Nf is melted.

  Next, the pressure roller 11 is rotated by the nip width (in this embodiment, about 5 mm) (step S902). The amount of rotation is ideally equal to the nip width, but may be an amount about 1.5 to 2 times the nip width in order to shorten the cooling time. If the pressure roller 11 has not yet rotated one turn (step S903), the cooling fan 13 is stopped, the heater is turned off, and the temperature drop of the thermistor 14 is confirmed (step S904).

  When the temperature drop of the thermistor 14 is 3 ° C. or more per second (step S906), the nip portion is regarded as frozen, and the cooling fan 13 is rotated and waits for 5 seconds at the heater control temperature 100 ° C. ( Step S907). Thereafter, the process returns to step S902.

  On the other hand, when the temperature drop of the thermistor 14 is less than 3 ° C. per second (step S506), the nip portion is regarded as not frozen, and the process returns to step S902 without doing anything.

  On the other hand, if the pressure roller 11 has rotated one revolution in step S903, confirmation of the feedback voltage value of the applied voltage Vto by ATVC (step S907) and confirmation of the reference voltage value for toner remaining amount detection (step S908). Is made.

  Here, if any of the values is smaller than the reference value, it is considered that the ice in the photosensitive drum 1 and the developing container 4b is not melted. Then, the cooling fan 13 is rotated while the heater control temperature is set to 100 ° C. and the fixing device 8 is rotated at half the normal speed (step S909).

  On the other hand, the applied voltage Vto by ATVC and the reference voltage value of the toner remaining amount detecting device are measured, and when both of them are cleared in advance, the ice melting mode is terminated (step S910).

  By performing the above procedure, it is possible to detect the in-machine temperature with higher accuracy.

<Third Embodiment>
Next, a printer according to still another embodiment of the present invention will be described. Hereinafter, a different part from 1st Embodiment is demonstrated, about the part which is the same as that of 1st Embodiment, or a similar part, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

  In the first embodiment and the second embodiment, it is assumed that the detected temperature value of the environmental temperature detection unit is higher than the actual temperature in the printer 100, and a mode for shifting to the ice melting mode is provided. In the actual market, the following can be considered.

  In midsummer, when the temperature is 40 ° C and the humidity exceeds 80%, at the time of SOHO, when the employee goes out in the morning and does not use the air conditioner indoors, the room temperature exceeds 50 ° C There is. When an employee returns to work in the afternoon and switches on the air conditioner near the printer, the temperature of the environmental detection sensor tends to be normal temperature and humidity, but the paper exposed to high temperature and humidity has absorbed moisture. .

  In the current technology, in order to suppress the curling of the absorbed paper in a high temperature and high humidity environment, when detecting that the high temperature and high humidity environment is detected, control is performed to lower the heater control temperature during paper feeding. However, assuming the above situation, if the environment detection sensor shows a normal value even though the paper exposed to high temperature and humidity is passed, the heater control temperature at normal temperature and normal humidity is reached. I will pass through the paper. For this reason, there is a strong influence on paper passing failure and paper discharge stacking.

  FIG. 11 is a diagram illustrating the moisture content of the paper, the heater control temperature, the curl amount, and the state of paper passing failure. As shown in the figure, it can be seen that when the heater temperature is high and the amount of moisture is large, the curl amount is large and a paper passing failure occurs.

  When a paper passing failure occurs, there are problems such as a decrease in productivity due to the stoppage of the apparatus and a failure of the apparatus due to the user pulling out the paper. Even if the paper can be passed, if the paper loaded in the paper output tray is greatly curled, the paper passed next will push the trailing edge of the loaded paper, curling the paper. There is also concern about the problem of endangering.

  FIG. 12 is a flowchart showing an operation of suppressing paper curl under high temperature and high humidity.

  As shown in the figure, first, when a print command is issued (step S1101), temperature and humidity data for the past three hours are acquired from the external temperature and humidity database server 300 (step S1102). When the detected temperature of the environmental sensor is 30 ° C. or higher (predetermined value or higher) and the detected humidity is 80% or higher (predetermined value or higher) (step S1103), the process proceeds to the high temperature and humidity mode (step S1104). . The high temperature and high humidity mode may be a curl reduction mode conventionally used.

  Even when the condition of step S1103 is not satisfied, if the outside air temperature is high temperature and humidity, there is a possibility that the temperature / humidity sensor and the in-flight actual temperature may be different. Therefore, it is checked whether the average temperature for the past three hours obtained from the temperature / humidity database server 300 is 30 ° C. or higher and the average humidity is 70% or higher (step S1105). If the condition in step S1105 is not satisfied, the process proceeds to the normal control mode (step S1106). On the other hand, when the condition of step S1105 is satisfied, when the temperature detected by the environmental sensor is 30 ° C. or lower and the humidity is 70% or lower is maintained for 1 hour or longer (step S1107), The control mode is entered (step S1106). On the other hand, if the condition in step S1107 is not satisfied, the process proceeds to the semi-high temperature control mode (step S1108). That is, in step S1105, when the average temperature is less than 30 ° C. (less than a predetermined value) and the average humidity is less than 70% (less than a predetermined value), the process shifts to the normal control mode (normal mode).

  FIG. 13 is a table showing that each mode is selected in accordance with the temperature / humidity range acquired from the external temperature / humidity database server 300 for the operation shown in FIG.

  As shown in the figure, although the detection of the environmental sensor in the printer 100 is regarded as important, even if the environmental sensor indicates normal temperature and normal humidity, if the outside air temperature is high temperature and humidity, it will take up to 1 hour from startup. Controlled in semi-high temperature and humidity mode.

  FIG. 14 is a table showing the heater control temperature, transfer bias value, and development bias voltage in the high temperature and high humidity mode, the semi-high temperature and high humidity mode, and the normal control mode.

  As shown in the figure, in the semi-high temperature / humidity mode, an intermediate value between the high temperature / humidity mode and the normal control mode is adopted. As a result, it is possible to suppress as much as possible the adverse effects of normal control when the room is cold despite the fact that it is actually hot and humid.

DESCRIPTION OF SYMBOLS 4 ... Developing device 4a ... Developing sleeve 4c ... Antenna electrode 5 ... Transfer roller 8 ... Fixing device 11 ... Pressure roller 12 ... Fixing heater 21 ... Computer 100 ... Image forming device 101 ... Device main body 201 ... Central control device 202 ... Control device Reference numeral 203: Environment determination unit 204: Transmission / reception device 205 ... Environment detection unit 206: Abnormality detection unit 207 ... Router 208 ... External network 209 ... Internal intranet 300 ... Temperature / humidity database server P ... Recording material

Claims (4)

An image forming apparatus for forming an image on a recording medium,
Environmental information detection means arranged inside the image forming apparatus and detecting the internal environmental information;
Environmental information acquisition means for acquiring environmental information measured outside the image forming apparatus;
The internal detection environment information detected by the environment information detection unit after the power of the image forming apparatus is turned on, and the environment information acquisition unit acquired within the predetermined time before turning on the power. Control means for controlling conditions related to image formation on a recording medium based on acquired environment information acquired from environmental information data measured a plurality of times externally,
The condition controlled by the control means is that when both information of the detected environment information after turning on the power and the acquired environment information before turning on the power are above a predetermined temperature, the power is turned on. When at least one of the detected environment information and the acquired environment information prior to turning on the power is less than a predetermined temperature,
An image forming apparatus.   The control means controls the condition based on the detected environment information without using the acquired environment information after controlling the condition based on the acquired environment information measured before the power is turned on. The image forming apparatus according to claim 1.   2. The control unit according to claim 1, wherein the control unit controls the condition based on the detected environment information without using the acquired environment information when a predetermined time elapses after the power is turned on. Image forming apparatus. An image forming apparatus according to any one of claims 1 to 3,
Storage means for storing environmental information data measured outside the image forming apparatus so that the environmental information acquisition means can acquire the data;
An image forming system comprising:

Images