JP5027478B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus in which a toner image transferred to a recording paper is thermally fixed via a fixing unit to form an image on the recording paper. In particular, the present invention relates to a copying machine, a facsimile machine, an Internet facsimile machine, a network printer, and a multifunction machine having at least one of these functions.

  2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine in which a toner image transferred onto a recording sheet is thermally fixed via a fixing unit to form an image on the recording sheet, an external atmosphere in which the image forming apparatus is disposed When the ambient temperature, which is a temperature, is low, the temperature of the recording paper is also low, and the fixability is lowered due to heat being taken from the fixing unit by the recording paper.

In order to solve the above-mentioned problem, for example, a temperature detection sensor is provided which is disposed at a predetermined position not affected by heat inside the copying machine main body and detects the atmospheric temperature in the copying machine main body. A copying machine is disclosed that corrects the fixing temperature to be higher when the detected in-machine temperature is equal to or lower than a preset threshold temperature (for example, 18 ° C.). (See Patent Document 1).
JP-A-7-114290

  However, even if the internal temperature is not lower than the threshold temperature (for example, 18 ° C.) (= higher than the threshold temperature), it is the atmospheric temperature outside the copying machine (for example, in the office). When the ambient temperature is equal to or lower than a threshold temperature (for example, 18 ° C.), the fixability may be deteriorated due to heat being taken away from the fixing unit by the recording paper.

  For example, when the copying machine has been in a power-off state (or sleep state) for a long period of time (for example, one day), the temperature inside the machine detected by the temperature detection sensor substantially matches the ambient temperature. By the copying machine, it is possible to prevent a decrease in fixing property due to heat deprived from the fixing unit by the recording paper. However, for example, immediately after the copying machine is continuously operated, the temperature inside the machine detected by the temperature detection sensor is higher than the ambient temperature, so even if the temperature inside the machine is higher than the threshold temperature, the atmosphere The fixing property may be lowered due to the low temperature and the heat deprived from the fixing unit by the recording paper.

  In order to solve this problem, a temperature sensor that detects the ambient temperature, which is the atmospheric temperature outside the copying machine (for example, in the office), may be provided, but the manufacturing cost of the copying machine increases. Will do.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an image forming apparatus capable of reliably preventing a decrease in fixing property due to a low atmospheric temperature with a simple configuration. It is said.

In order to achieve the above object, an image forming apparatus of the present invention is an image forming apparatus that forms an image on a recording paper by thermally fixing the toner image transferred to the recording paper through a fixing unit. An in-machine temperature detecting means for detecting an in-machine temperature that is an atmospheric temperature in the image forming apparatus, and an external air temperature at which the image forming apparatus is disposed based on the in-machine temperature detected by the in-machine temperature detecting means. A first determination unit that determines whether or not a certain ambient temperature is equal to or lower than a first threshold temperature set in advance; and a case where the first determination unit determines that the ambient temperature is equal to or lower than a first threshold temperature. Correction means for correcting a set value of the fixing temperature in the fixing unit.

In the above structure, the correction means, when it is determined that the ambient temperature is not higher than the first threshold temperature by the first judging means, be corrected setting value of the transport speed of the recording sheet in the fixing unit Good.

In the above configuration, when the correction unit determines that the first determination unit determines that the ambient temperature is equal to or lower than the first threshold temperature, the correction unit performs a printing operation after receiving an instruction to start printing. You may correct | amend the setting value of the waiting time which is time until it starts .

Further, in the above configuration, a start internal temperature that is an internal temperature detected via the internal temperature detection means when the first determination means receives an instruction to start printing is preset. When the temperature is equal to or lower than the second threshold temperature, the ambient temperature may be determined to be equal to or lower than the first threshold temperature .

In the above configuration, the second threshold temperature may be set to substantially the same temperature as the first threshold temperature .

In the above configuration, when the temperature storage means for storing the in-machine temperature and the instruction to start printing are received, the start in-machine temperature that is detected through the in-machine temperature detection means is set. A temperature update unit for recording in the temperature storage unit, a date / time storage unit for storing date / time information, a time measurement function, measures the date / time at the end of the printing process, and records the date / time information in the date / time storage unit When an instruction to start printing is received, the date and time when the instruction is received, and the date and time information at the end of the previous printing process stored in the date and time storage means A second determination unit that determines whether or not a pause period that is an interval between them is equal to or less than a preset threshold period, wherein the first determination unit stores the previous time stored in the temperature storage unit Printing process When the starter internal temperature is equal to or lower than a preset third threshold temperature, and the second determination means determines that the pause period is equal to or less than a preset threshold period, the ambient temperature is It may be determined that the temperature is equal to or lower than one threshold temperature .

Further, in the above configuration, the third threshold temperature may be set to substantially the same temperature as the first threshold temperature .

In the above configuration, the fixing temperature detecting means for detecting the fixing temperature of the fixing unit and the fixing temperature detected by the fixing temperature detecting means at the time when an instruction to start printing is received are preset. And a third determination means for determining whether or not the temperature is equal to or lower than a fourth threshold temperature, wherein the first determination means sets in advance the internal temperature at the time of the previous printing process stored in the temperature storage means The ambient temperature is equal to or lower than the first threshold temperature when the third determination unit determines that the fixing temperature is equal to or lower than the fourth threshold temperature. You may judge .

In the above configuration, the fourth threshold temperature may be set to the in-machine temperature detected by the in-machine temperature detection means when an instruction to start printing is received .

According to the image forming apparatus of the present invention , based on the in-machine temperature, which is the atmospheric temperature in the image forming apparatus, the ambient temperature, which is the external atmospheric temperature in which the image forming apparatus is disposed, is set in advance. When it is determined whether or not the temperature is equal to or lower than the threshold temperature, and it is determined that the ambient temperature is equal to or lower than the first threshold temperature, the setting value of the fixing temperature in the fixing unit is corrected. It is possible to reliably prevent a decrease in fixability due to the low.

  That is, even when the in-machine temperature is higher than the threshold temperature, when it is determined that the ambient temperature is equal to or lower than the first threshold temperature, the setting value of the fixing temperature in the fixing unit is corrected (for example, on the high temperature side). Therefore, it is possible to prevent a decrease in fixability due to heat being taken from the fixing unit by the recording paper. Further, since it is determined whether or not the ambient temperature is equal to or lower than the first threshold temperature based on the in-machine temperature, there is no need to add a temperature sensor or the like, so the fixing property is reduced with a simple configuration. Can be prevented.

In the above configuration, when it is determined that the ambient temperature is equal to or lower than the first threshold temperature, the set value of the recording paper conveyance speed in the fixing unit is corrected (for example, 5% is corrected to the low speed side). When, it is possible to further reliably prevent the deterioration of the fixing property caused by the ambient temperature is low.

Further, in the above configuration, when it is determined that the ambient temperature is equal to or lower than the first threshold temperature, setting of a standby time that is a time from when an instruction to start printing is received until the printing operation is started value is corrected (e.g., 10 sec is the correction to be longer by) and can be ambient temperature may further be reliably prevent a decrease in fixability due to low.

In the above configuration, the ambient temperature is equal to or lower than the first threshold temperature when the initial temperature inside the apparatus detected at the time when the instruction to start printing is received is equal to or lower than the second threshold temperature. If it is determined that it is possible to determine whether the ambient temperature is below a first threshold temperature with a simple configuration.

  That is, for example, when the image forming apparatus is in a power-off state (or sleep state) for a long period (for example, for one day), the in-machine temperature is substantially equal to the ambient temperature, and thus the in-machine temperature is the first. When the temperature is equal to or lower than the threshold temperature, it can be determined that the ambient temperature is equal to or lower than the first threshold temperature. In this case, the second threshold temperature may be set to substantially the same temperature as the first threshold temperature.

In the above structure, the second threshold temperature, when set to a first threshold temperature and substantially the same temperature, it is possible to determine whether the ambient temperature is below a first threshold temperature with a simple structure .

  For example, when the image forming apparatus is in a power-off state (or sleep state) for a long time (for example, for one day), the in-machine temperature substantially matches the ambient temperature, and thus the in-machine temperature is the second threshold temperature. When the temperature is equal to or lower than (≈first threshold temperature), it can be determined that the ambient temperature is equal to or lower than the first threshold temperature.

In the above configuration, the date and time when the start internal temperature at the time of the previous printing process is equal to or lower than a preset third threshold temperature and an instruction to start printing is received, and the previous printing process If the end date and time information, the rest period is a period between is less than a preset threshold time period, when the ambient temperature is determined to be equal to or less than the first threshold temperature, the ambient temperature is the first threshold value It is possible to accurately determine whether the temperature is equal to or lower than the temperature.

  That is, for example, if the image forming apparatus has been in a power-off state (or sleep state) for a long time (for example, for one day) before the previous printing process, the starting internal temperature at the previous printing process is the ambient temperature. Therefore, if the start internal temperature at the time of the previous printing process is equal to or lower than the first threshold temperature, the ambient temperature at the start of the previous printing process is equal to or lower than the first threshold temperature. In this case, the third threshold temperature may be set to substantially the same temperature as the first threshold temperature.

  In addition, a threshold period (for example, 2 hours) in which a pause period, which is a period between the date and time when an instruction to start printing is received and the date and time information at the end of the previous printing process, is set in advance. In the following cases, it is estimated that the ambient temperature at the time when the instruction to start printing is accepted substantially matches the ambient temperature before the previous printing process.

  Therefore, the date and time when the start internal temperature at the time of the previous printing process is equal to or lower than a preset third threshold temperature (≈first threshold temperature) and an instruction to start printing is received, and the previous time When the suspension period, which is a period between the date and time information at the end of the printing process, is not more than a preset threshold period (for example, 2 hours), it is determined that the ambient temperature is not more than the first threshold temperature. It can be done.

In the above structure, the third threshold temperature, when set to a first threshold temperature and substantially the same temperature, it is possible to determine whether the ambient temperature is below a first threshold temperature with a simple structure .

  That is, for example, if the image forming apparatus has been in a power-off state (or sleep state) for a long time (for example, for one day) before the previous printing process, the starting internal temperature at the previous printing process is the ambient temperature. Therefore, when the internal temperature at the time of the previous printing process is equal to or lower than the third threshold temperature (≈first threshold temperature), the ambient temperature at the start of the previous printing process is the first threshold temperature. It can be determined that:

Further, in the above configuration, the fixing temperature of the fixing unit at the time when the in-machine temperature at the time of the previous printing process is equal to or lower than a preset third threshold temperature and an instruction to start printing is received. If it is determined that the fourth threshold temperature below the ambient temperature is determined to be equal to or less than the first threshold temperature, that the ambient temperature is accurately determined to or less than the first threshold temperature it can.

  That is, for example, if the image forming apparatus has been in a power-off state (or sleep state) for a long time (for example, for one day) before the previous printing process, the starting internal temperature at the previous printing process is the ambient temperature. Therefore, if the start internal temperature at the time of the previous printing process is equal to or lower than the first threshold temperature, the ambient temperature at the start of the previous printing process is equal to or lower than the first threshold temperature. In this case, the third threshold temperature may be set to substantially the same temperature as the first threshold temperature.

  Further, when the fixing temperature of the fixing unit at the time when an instruction to start printing is received is equal to or lower than a fourth threshold temperature (for example, the temperature inside the apparatus), the fixing is caused by the low ambient temperature. Since it is estimated that the fixing temperature of the unit is cooled more rapidly than the in-machine temperature, which is the atmospheric temperature in the image forming apparatus, it is estimated that there is a high possibility that the ambient temperature is equal to or lower than the first threshold temperature. .

  Therefore, the temperature of the fixing unit at the time when the in-machine temperature at the time of the previous printing process is equal to or lower than a preset third threshold temperature (≈first threshold temperature) and an instruction to start printing is received. When it is determined that the fixing temperature is equal to or lower than the fourth threshold temperature (for example, the in-machine temperature), it is possible to determine that the ambient temperature is equal to or lower than the first threshold temperature.

In the above structure, the fourth threshold temperature, if an instruction to start printing is set to the detected internal temperature at the time of accepted, whether the ambient temperature is below a first threshold temperature Can be determined with a simple configuration.

  That is, when the fixing temperature of the fixing unit at the time when an instruction to start printing is received is equal to or lower than the in-machine temperature, the fixing temperature of the fixing unit is reduced due to the low ambient temperature. Since it is estimated that the cooling is performed more rapidly than the in-machine temperature, which is the atmospheric temperature in the apparatus, it is estimated that there is a high possibility that the ambient temperature is equal to or lower than the first threshold temperature.

  Hereinafter, an example of an image forming apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an example of a schematic configuration of an image forming apparatus according to the present invention. Here, the case where the image forming apparatus is a printer will be described. However, the image forming apparatus may be another image forming apparatus (for example, a facsimile, an internet facsimile, a copying machine, a multifunction machine, etc.) that forms an image on recording paper. Good. As shown in FIG. 1, the printer 100 includes a control unit 1, a display unit 2, an operation unit 3, a print processing unit 4, an in-machine temperature sensor 5, and a fan 6. The printer 100 is communicably connected to a personal computer (PC) (not shown), receives image information from the personal computer (PC), and forms an image corresponding to the received image information on a recording sheet. It is.

  The control unit 1 controls the overall operation of the printer 100, and includes a CPU (Central Processing Unit) 11, a RAM (Random Access Memory) 12, and a ROM (Read Only Memory) not shown.

  The display unit 2 includes an LCD (Liquid Crystal Display), an LED (Light Emitting Diode), and the like, and displays setting information, guidance information, message information, and the like so as to be visible to the user based on instructions from the control unit 1 (CPU 11). To do.

  The operation unit 3 receives operation input from the user, generates operation input information corresponding to the received operation input, and outputs the operation input information to the control unit 1 (CPU 11). The operation unit 3 includes, for example, various buttons such as a numeric keypad and a start button, and a touch panel formed integrally with the LCD disposed in the display unit 2.

  The print processing unit 4 forms an image (in this case, an image corresponding to a document image) on a recording sheet by electrophotography, and includes a developing unit 41, a photosensitive unit 42, a fixing unit 43, and a transport unit. A control unit 44 is provided. The developing unit 41 forms a toner image by attaching toner to an electrostatic latent image formed by a laser beam scanning unit (not shown) on a photosensitive drum disposed in the photosensitive unit 42.

  The photosensitive unit 42 includes a photosensitive drum, and transfers the toner image formed on the photosensitive drum by the developing unit 41 onto a recording sheet. The fixing unit 43 melts and fixes the toner image by fixing the toner image transferred from the photosensitive drum to the recording paper by the photosensitive unit 42 by sandwiching the recording paper with a pair of heating rollers. The image forming apparatus includes a fixing temperature sensor 431 and a heating unit 432.

  The fixing temperature sensor 431 (corresponding to a part of the fixing temperature detecting means) measures the surface temperature of the heating roller, and includes a thermistor or the like. The heating unit 432 includes a heating roller pair, and heats the heating roller by Joule heat (or induction heating). A conveyance control unit 44 (corresponding to a part of the correction unit) controls the conveyance of the recording paper in the print processing unit 4 based on an instruction from the CPU 11. Here, the conveyance control unit 44 controls the conveyance speed in the fixing unit 43 based on an instruction from the CPU 11.

  The in-machine temperature sensor 5 (corresponding to a part of the in-machine temperature detecting means) detects the in-machine temperature that is the atmospheric temperature in the printer 100, and is a low temperature thermistor (for example, a measurement temperature range: 0 ° C. to 100 ° C.). ° C) and the like. The fan 6 sucks the atmosphere outside the printer 100 into the printer 100 (or discharges the atmosphere inside the printer 100 to the outside of the printer 100), and the temperature inside the printer 100 is increased by the fixing unit 43 and the like. This is to prevent this.

  FIG. 2 is a perspective view of the printer 100 showing an example of arrangement positions of the fixing temperature sensor 431 and the in-machine temperature sensor 5. Here, the cover of the side surface of the printer 100 (the left side surface in the drawing) is removed, and the fixing unit 43 is drawn out so as to be visible. The fixing temperature sensor 431 includes a non-contact temperature sensor 431a and a contact temperature sensor 431b.

  The non-contact temperature sensor 431a is disposed substantially at the center in the width direction of the heating roller, and detects the surface temperature of the heating roller in a state where it is not in contact with the heating roller (= a state separated from the surface of the heating roller). This is a high temperature type thermistor (for example, measurement temperature range: 100 ° C. to 250 ° C.). The contact temperature sensor 431b is disposed at the end of the heating roller in the width direction (here, the right end in the figure) and is in contact with the heating roller (= sliding contact with the surface of the heating roller). It is a contact type high temperature thermistor (for example, measurement temperature range: 100 ° C. to 250 ° C.) for detecting the surface temperature of the roller.

  The in-machine temperature sensor 5 is inside the cover (not shown) of the side surface (left side surface in the figure) of the detachable printer 100 and protects the print processing unit 4 of the printer 100 from being contacted from the outside. This is a low temperature thermistor (for example, measurement temperature range: 0 ° C. to 100 ° C.) that is locked in place on the outer surface of the protective plate 45 and detects the atmospheric temperature inside the printer 100. The in-machine temperature sensor 5 is disposed at a position separated from the fan 6 so as not to be affected by the atmospheric temperature sucked or discharged through the fan 6.

  FIG. 3 is a functional configuration diagram illustrating an example of a main part of the printer 100. The CPU 11 functionally includes an in-machine temperature detection unit 111, a temperature update unit 112, a timing unit 113, a second determination unit 114, a fixing temperature detection unit 115, a third determination unit 116, a first determination unit 117, and a correction unit. 118 is provided. The RAM 12 functionally includes a temperature storage unit 121 and a date / time storage unit 122.

  Here, the CPU 11 reads and executes a program stored in advance in a ROM (not shown) or the like, thereby executing an in-machine temperature detection unit 111, a temperature update unit 112, a time measurement unit 113, a second determination unit 114, and a fixing temperature detection unit. 115, the third determination unit 116, the first determination unit 117, and the correction unit 118. The RAM 12 functions as a function unit such as the temperature storage unit 121 and the date / time storage unit 122.

  Of various data stored in the RAM 12 and ROM, data that can be stored in a removable recording medium is read by a driver such as a hard disk drive, an optical disk drive, a flexible disk drive, a silicon disk drive, or a cassette medium reader. In this case, the recording medium is, for example, a hard disk, an optical disk, a flexible disk, a CD, a DVD, a semiconductor memory, or the like.

  The in-machine temperature detection unit 111 (corresponding to a part of the in-machine temperature detection means) detects the in-machine temperature TI, which is the atmospheric temperature in the printer 100, via the in-machine temperature sensor 5.

  The temperature update unit 112 (corresponding to the temperature update unit) detects the in-machine temperature detected via the in-machine temperature detection unit 111 when an instruction to start printing is received from a personal computer (PC) (not shown) or the like. The start machine temperature TI0, which is the temperature, is recorded in the temperature storage unit 121.

  The timekeeping unit 113 (corresponding to timekeeping means) has a timekeeping function, measures the date and time when the printing process is finished, and records the date and time information in the date and time storage unit 122.

  When an instruction to start printing is received from a personal computer (PC) (not shown) or the like, the second determination unit 114 (corresponding to the second determination means) Whether the pause period IP, which is a period between the date and time information at the end of the previous print process stored in the date storage unit 122, is equal to or less than a preset threshold period SHI (for example, 2 hours). Is determined.

  The fixing temperature detecting unit 115 (corresponding to a part of the fixing temperature detecting means) detects the fixing temperature TB of the fixing unit via the fixing temperature sensor 431 (= non-contact temperature sensor 431a and contact temperature sensor 431b). It is.

  The third determination unit 116 (corresponding to the third determination unit) detects the fixing detected by the fixing temperature detection unit 115 when an instruction to start printing is received from a personal computer (PC) (not shown) or the like. It is determined whether or not the temperature TB is equal to or lower than a preset fourth threshold temperature SH4 (for example, the in-machine temperature TI0 detected by the in-machine temperature detection unit 111 when an instruction to start printing is received). Is.

  A first determination unit 117 (corresponding to a first determination unit) is provided outside the printer 100 (for example, the printer 100 is installed) based on the internal temperature detected by the internal temperature detection unit 111. It is determined whether or not the ambient temperature TA, which is the ambient air temperature, is equal to or lower than a preset first threshold temperature SH1 (for example, 18 ° C.).

  Specifically, the first determination unit 117 has a preset in-machine temperature TI0 that is the in-machine temperature TI detected via the in-machine temperature detection unit 111 at the time when an instruction to start printing is received. When the temperature is equal to or lower than the second threshold temperature SH2 (for example, 18 ° C.), the ambient temperature TA is determined to be equal to or lower than the first threshold temperature SH1 (for example, 18 ° C.).

  Further, the first determination unit 117 has a start internal temperature TI0 stored in the temperature storage unit 121 at the time of the previous printing process that is equal to or lower than a preset third threshold temperature SH3 (here, 18 ° C.), and When the second determination unit 114 determines that the suspension period IP is equal to or less than a preset threshold period SHI (for example, 2 hours), the ambient temperature TA is the first threshold temperature SH1 (here, 18 ° C.). It is determined that:

  Further, the first determination unit 117 has a start internal temperature TI0 at the previous printing process stored in the temperature storage unit 121 that is equal to or lower than a preset third threshold temperature SH3 (here, 18 ° C.), and The fixing temperature TB is equal to or lower than the fourth threshold temperature SH4 (here, the in-machine temperature TI0 detected by the in-machine temperature detection unit 111 when an instruction to start printing is received) by the third determination unit 116. When it is determined, it is determined that the ambient temperature TA is equal to or lower than the first threshold temperature SH1 (here, 18 ° C.).

  The correction unit 118 (corresponding to a part of the correction unit), when the first determination unit 117 determines that the ambient temperature TA is equal to or lower than the first threshold temperature SH1 (here, 18 ° C.), the fixing unit 43. The setting value of the fixing temperature in the (heating unit 432) is corrected. For example, the correction unit 118 increases the set value of the fixing temperature TB by 10 ° C. when the first determination unit 117 determines that the ambient temperature TA is equal to or lower than the first threshold temperature SH1 (here, 18 ° C.). It is something to be made.

  Further, when the first determination unit 117 determines that the ambient temperature TA is equal to or lower than the first threshold temperature SH1 (here, 18 ° C.), the correction unit 118 causes the conveyance control unit 44 to move inside the fixing unit 43. In this case, the set value of the recording paper conveyance speed is corrected. For example, when the first determination unit 117 determines that the ambient temperature TA is equal to or lower than the first threshold temperature SH1 (here, 18 ° C.), the correction unit 118 reduces the set value of the conveyance speed by 5%. Is.

  Furthermore, when the first determination unit 117 determines that the ambient temperature TA is equal to or lower than the first threshold temperature SH1 (here, 18 ° C.), the correction unit 118 prints from a personal computer (PC) (not shown) or the like. The setting value of the standby time, which is the time from when the instruction to start the printing operation is received until the printing operation is started, is corrected. For example, when the first determination unit 117 determines that the ambient temperature TA is equal to or lower than the first threshold temperature SH1 (here, 18 ° C.), the correction unit 118 increases the set standby time by 10 seconds. It is.

  The temperature storage unit 121 (corresponding to temperature storage means) stores the in-machine temperature TI, and the temperature update unit 112 records the in-machine temperature TI (starting in-machine temperature TI0).

  The date / time storage unit 122 (corresponding to the date / time storage unit) stores date / time information, and the time measuring unit 113 records date / time information at the time of ending the printing process.

  FIG. 4 is a graph showing an example of changes in the in-machine temperature TI, the fixing temperature TB, and the ambient temperature TA. In the figure, the horizontal axis is time, and the vertical axis is temperature. A graph G1 is a graph showing a change in the fixing temperature TB, a graph G2 is a graph showing a change in the in-machine temperature TI, and a graph G3 is a graph showing a change in the ambient temperature TA. Here, for convenience, the ambient temperature TA is assumed to be a constant value (for example, 10 ° C.) that is equal to or lower than the first threshold temperature SH1 (here, 18 ° C.).

  Here, an instruction to start the previous printing is received at the timing of time T0 and the printing process is started (heating of the heating unit 432 of the fixing unit 43 is started), and the previous printing is completed at the timing of time T2. Thus, the printer enters a standby state (= sleep state: heating is stopped in the heating unit 432 of the fixing unit 43), and an instruction to start the current printing is received at the timing of time T3 and is returned from the standby state. The printing process is started (heating of the heating unit 432 of the fixing unit 43 is started).

  When heating of the heating unit 432 is started at the timing of time T0, the fixing temperature TB rises, and accordingly, the in-machine temperature TI also rises. At the time T1, the in-machine temperature TI becomes the first threshold temperature SH1 (here, , 18 ° C.). Further, when the heating of the heating unit 432 is stopped at the timing of time T2, the fixing temperature TB and the in-machine temperature TI are lowered. At the timing of time T22, the fixing temperature TB coincides with the in-machine temperature TI. Here, the fixing temperature TB is more easily cooled than the in-machine temperature TI, the fixing temperature TB matches the in-machine temperature TI at the time T22, and the first threshold temperature SH1 (here, the time T21). 18 ° C).

  Further, when heating of the heating unit 432 is started again at time T3, the fixing temperature TB rises, and accordingly, the in-machine temperature TI also rises, and the fixing temperature TB is increased to the first threshold temperature SH1 ( Here, the temperature reaches 18 ° C., and the fixing temperature TB coincides with the in-machine temperature TI at the timing of time T32. If an instruction to start printing at this time is not received at time T3, the in-machine temperature TI is set to the first threshold temperature SH1 (here, at time T4, as shown by the broken line in the figure). , 18 ° C.).

  Thus, even when the heating of the heating unit 432 is stopped at the timing of time T2, the in-machine temperature TI is the first threshold temperature SH1 (here, 18) within the period P1 from time T2 to time T4. Therefore, when the in-machine temperature TI is regarded as the ambient temperature TA and the in-machine temperature TI is equal to or lower than the first threshold temperature SH1, the correction is not performed in the method in which the correction unit 118 performs the correction. As a result, a fixing failure occurs.

  On the other hand, when the threshold period SHI is set to the period P1 from the time T2 to the time T4, when the instruction to start printing is received within the period P1, the second determination unit 114 pauses. The period IP is determined to be equal to or less than the threshold period SHI (for example, 2 hours), and the first determination unit 117 determines that the ambient temperature TA is equal to or less than the first threshold temperature SH1 (here, 18 ° C.). In other words, in this case, the correction is performed by the correction unit 118, so that it is possible to prevent the occurrence of fixing failure.

  Further, since the fixing temperature TB is in a state equal to or lower than the in-machine temperature TI within the period P2 from the time T22 to the time T32, when an instruction to start printing is received within the period P2, the third The determination unit 116 determines that the fixing temperature TB is equal to or lower than the starter internal temperature TI0, and the first determination unit 117 determines that the ambient temperature TA is equal to or lower than the first threshold temperature SH1 (here, 18 ° C.). In other words, in this case, the correction is performed by the correction unit 118, so that it is possible to prevent the occurrence of fixing failure.

  FIG. 3 is a flowchart showing an example of the operation of the printer 100 (mainly the CPU 11). First, the first determination unit 117 determines whether an instruction to start printing is received from a personal computer (PC) or the like (S101). If it is determined that an instruction to start printing has not been received (NO in S101), the process is set to a standby state. If it is determined that an instruction to start printing has been received (YES in S101), the first determination unit 117 uses the start internal temperature TI0 stored in the temperature storage unit 121 during the previous printing process. It is determined whether or not the temperature is equal to or lower than the third threshold temperature SH3 (here, 18 ° C.) (S103). If it is determined that the in-machine temperature TI0 is not equal to or lower than the third threshold temperature SH3 (NO in S103), the process proceeds to step S109.

  When it is determined that the starter internal temperature TI0 is equal to or lower than the third threshold temperature SH3 (YES in S103), the second determination unit 114 sets the suspension period IP to a threshold period SHI (here, 2 hours). It is determined whether or not (S105). If it is determined that the suspension period IP is 2 hours or less (YES in S105), the process proceeds to step S111. When it is determined that the suspension period IP is not 2 hours or less (= more than 2 hours) (NO in S105), the third determination unit 116 determines whether the fixing temperature TB is equal to or lower than the in-machine temperature TI0. A determination is made (S107). If it is determined that fixing temperature TB is equal to or lower than in-machine temperature TI0 (YES in S107), the process proceeds to step S111.

  If it is determined that the fixing temperature TB is not equal to or lower than the in-machine temperature TI0 (= higher than the in-machine temperature TI0) (S107), or if NO in step S103, the first determination unit 117 starts printing. Determination of whether the starting in-machine temperature TI0, which is the in-machine temperature TI detected through the in-machine temperature detection unit 111 at the time when the instruction is received, is equal to or lower than the second threshold temperature SH2 (here, 18 ° C.) Is performed (S109).

  When it is determined that the starter internal temperature TI0 is equal to or lower than 18 ° C. (YES in S109), in the case of YES in Step S105, or in the case of YES in Step S107, the correction unit 118 sets the set value of the fixing temperature, Correction of the set value of the conveyance speed and the set value of the standby time is performed (S111). When it is determined that the starter internal temperature TI0 is not 18 ° C. or lower (NO in S109), or when the process of step S111 is completed, printing is started and the process is terminated.

  In this way, based on the in-machine temperature TI that is the atmospheric temperature in the printer 100, the ambient temperature TA that is the external atmospheric temperature in which the printer 100 is disposed is equal to or lower than the first threshold temperature SH1 that is set in advance ( Here, when it is determined whether or not the ambient temperature TA is equal to or lower than the first threshold temperature SH1, the setting value of the fixing temperature TB in the fixing unit 43 is corrected. With a simple configuration, it is possible to reliably prevent the fixing property from being lowered due to the low ambient temperature TA.

  That is, even when the in-machine temperature TI is higher than the first threshold temperature SH1 (here, 18 ° C.), it is determined that the ambient temperature TA is equal to or lower than the first threshold temperature SH1 (here, 18 ° C.). In addition, since the set value of the fixing temperature TB in the fixing unit 43 is corrected (for example, 10 ° C. is corrected on the high temperature side), the fixing property is deteriorated due to the heat deprived from the fixing unit 43 by the recording paper. Can be prevented. Further, since it is determined whether or not the ambient temperature TA is equal to or lower than the first threshold temperature SH1 (here, 18 ° C.) based on the in-machine temperature TI, there is no need to additionally provide a temperature sensor or the like. Therefore, it is possible to prevent a decrease in fixability with a simple configuration.

  When it is determined that the ambient temperature TA is equal to or lower than the first threshold temperature SH1 (here, 18 ° C.), the set value of the recording paper conveyance speed in the fixing unit 43 is corrected (for example, the low speed side). Therefore, it is possible to prevent the deterioration of the fixing property due to the low ambient temperature TA more reliably.

  Furthermore, it is the time from when an instruction to start printing is received until the printing operation is started when it is determined that the ambient temperature TA is equal to or lower than the first threshold temperature (here, 18 ° C.). Since the set value of the standby time is corrected (for example, correction is made to be increased by 10 seconds), it is possible to more reliably prevent the fixing property from being lowered due to the low ambient temperature TA.

  In addition, when the in-machine temperature TI0, which is the in-machine temperature TI detected when the instruction to start printing is received, is equal to or lower than the second threshold temperature SH2 (here, 18 ° C.), the ambient temperature TA Is determined to be equal to or lower than the first threshold temperature (here, 18 ° C.), it is determined with a simple configuration whether the ambient temperature TA is equal to or lower than the first threshold temperature (here, 18 ° C.). Can do.

  That is, for example, when the printer 100 is in a power-off state (or sleep state = standby state) for a long period (for example, one day), the in-machine temperature TI substantially matches the ambient temperature TA. When the temperature TI is equal to or lower than the first threshold temperature SH1 (here, 18 ° C.), it can be determined that the ambient temperature TA is equal to or lower than the first threshold temperature SH1 (here, 18 ° C.). In this case, the second threshold temperature SH2 may be set to substantially the same temperature (here, 18 ° C.) as the first threshold temperature SH1.

  In addition, since the second threshold temperature SH2 is set to substantially the same temperature (here, 18 ° C.) as the first threshold temperature SH1, whether or not the ambient temperature TA is equal to or lower than the first threshold temperature SH1 is simplified. Can be determined by configuration.

  For example, when the printer 100 is in a power-off state (or sleep state = standby state) for a long period of time (for example, one day), the in-machine temperature TI substantially matches the ambient temperature TA, so the in-machine temperature is When the temperature is equal to or lower than the second threshold temperature SH2 (≈first threshold temperature SH1), it can be determined that the ambient temperature TA is equal to or lower than the first threshold temperature (here, 18 ° C.).

  Further, the date and time when the start internal temperature TI0 at the time of the previous printing process is equal to or lower than a preset third threshold temperature SH3 (here, 18 ° C.) and an instruction to start printing is received. When the suspension period IP, which is a period between the date and time information at the end of the previous printing process, is equal to or lower than a preset threshold (here, 2 hours), the ambient temperature TA is equal to or lower than the first threshold temperature SH1. Since it is determined that it is (here 18 ° C.), it can be accurately determined whether or not the ambient temperature TA is equal to or lower than the first threshold temperature SH1 (here 18 ° C.).

  That is, for example, if the printer 100 has been in a power-off state (or sleep state = standby state) for a long period of time (for example, for one day) before the previous printing process, the start internal temperature TI0 during the previous printing process Is substantially the same as the ambient temperature TA, and therefore, when the start machine temperature TI0 at the time of the previous printing process is equal to or lower than the first threshold temperature SH1 (here, 18 ° C.), The ambient temperature TA is equal to or lower than the first threshold temperature SH1 (here, 18 ° C.). In this case, the third threshold temperature SH3 may be set to substantially the same temperature (here, 18 ° C.) as the first threshold temperature SH1.

  In addition, a suspension period IP that is a period between the date and time when an instruction to start printing is received and the date and time information at the end of the previous printing process is set in advance (in this case, 2 hours) In the case of the following, it is presumed that the ambient temperature TA at the time when the instruction to start printing is accepted is substantially the same as the ambient temperature TA before the previous printing process.

  Therefore, the date and time when the in-machine temperature TI0 at the time of the previous printing process is equal to or lower than a preset third threshold temperature SH3 (≈first threshold temperature SH1) and an instruction to start printing is received. And the date and time information at the end of the previous printing process, the suspension temperature IP, which is a period between them, is equal to or less than a preset threshold (here, 2 hours), and the ambient temperature TA is the first threshold temperature SH1. It can be determined that the temperature is 18 ° C. or less.

  In addition, since the third threshold temperature SH3 is set to substantially the same temperature (here, 18 ° C.) as the first threshold temperature SH1, whether or not the ambient temperature TA is equal to or lower than the first threshold temperature is simplified. Can be determined by configuration.

  That is, for example, if the printer 100 has been in a power-off state (or sleep state = standby state) for a long period of time (for example, for one day) before the previous printing process, the start internal temperature TI0 during the previous printing process Is substantially the same as the ambient temperature TA, and therefore, when the in-machine temperature TI0 at the time of the previous printing process is equal to or lower than the third threshold temperature SH3 (≈first threshold temperature SH1), It can be determined that the ambient temperature TA is equal to or lower than the first threshold temperature SH1.

  The fixing temperature TB of the fixing unit 43 at the time when the in-machine temperature TI0 at the time of the previous printing process is equal to or lower than a preset third threshold temperature SH3 and an instruction to start printing is received is the fourth. When it is determined that the temperature is equal to or lower than the threshold temperature SH4 (here, 18 ° C.), the atmospheric temperature TA is determined to be equal to or lower than the first threshold temperature SH1, and thus the atmospheric temperature TA is equal to or lower than the first threshold temperature SH1. It can be accurately determined whether or not.

  That is, for example, if the printer 100 has been in a power-off state (or sleep state = standby state) for a long period of time (for example, for one day) before the previous printing process, the start internal temperature TI0 during the previous printing process Is substantially the same as the ambient temperature TA, and therefore, when the start machine temperature TI0 at the time of the previous printing process is equal to or lower than the first threshold temperature SH1 (here, 18 ° C.), The ambient temperature TA is equal to or lower than the first threshold temperature SH1. In this case, the third threshold temperature SH3 may be set to substantially the same temperature (here, 18 ° C.) as the first threshold temperature SH1.

  Further, when the fixing temperature of the fixing unit at the time when the instruction to start printing is received is equal to or lower than the fourth threshold temperature SH4 (for example, the in-machine temperature TI0), it is caused by the low ambient temperature TA. Thus, since the fixing temperature TB of the fixing unit 43 is estimated to be cooled more rapidly than the in-machine temperature TI, which is the atmospheric temperature in the printer 100, the ambient temperature TA is likely to be equal to or lower than the first threshold temperature SH1. It is estimated that.

  Therefore, the start internal temperature TI0 at the time of the previous printing process is equal to or lower than a preset third threshold temperature SH3 (≈first threshold temperature SH1), and when an instruction to start printing is received. When it is determined that the fixing temperature TB of the fixing unit 43 is equal to or lower than the fourth threshold temperature SH4 (for example, the in-machine temperature TI), it can be determined that the ambient temperature TA is equal to or lower than the first threshold temperature SH1. .

  Further, since the fourth threshold temperature SH4 is set to the in-machine temperature TI0 detected at the time when the instruction to start printing is received, whether or not the ambient temperature TA is equal to or lower than the first threshold temperature SH1. Can be determined with a simple configuration.

  That is, when the fixing temperature TB of the fixing unit 43 at the time when the instruction to start printing is received is equal to or lower than the in-machine temperature TI, the fixing of the fixing unit 43 is caused by the low ambient temperature TA. Since the temperature TB is estimated to be cooled more rapidly than the in-machine temperature TI, which is the atmospheric temperature in the printer 100, it is estimated that there is a high possibility that the ambient temperature TA is equal to or lower than the first threshold temperature SH1.

The present invention can also be applied to the following forms.
(A) In the present embodiment, the correction unit 118 corrects the setting value of the fixing temperature TB, the setting value of the conveyance speed, and the setting value of the standby time. However, the correction unit 118 corrects the fixing temperature TB. It is also possible to correct at least one of the set value, the conveyance speed set value, and the standby time set value.

  (B) In the present embodiment, the case where the second determination unit 114 determines whether or not the suspension period IP is equal to or less than the preset threshold period SHI has been described. It may be configured to determine whether or not the period from the time when the instruction for starting the printing process is received to the time when the instruction for starting the current printing process is received is equal to or less than a preset threshold period SHI. In this case, since the determination is made regardless of the previous print processing period, it can be more accurately determined whether or not the ambient temperature TA is equal to or lower than the first threshold temperature SH1.

  (C) In the present embodiment, the case where the third determination unit 116 determines whether or not the fixing temperature TB is equal to or lower than the in-machine temperature TI0 has been described. However, the fixing temperature TB is set based on the first threshold temperature SH1. It is also possible to determine whether or not the temperature is equal to or lower than the fourth threshold temperature SH4. That is, the fourth threshold temperature SH4 may be set based on the first threshold temperature SH1. For example, the fourth threshold temperature SH4 may be a sum obtained by adding a predetermined temperature (for example, 3 ° C.) to the first threshold temperature SH1. In this case, it is possible to more accurately determine whether or not the ambient temperature TA is equal to or lower than the first threshold temperature SH1 by appropriately setting the predetermined temperature.

  (D) In the present embodiment, the case where the time measuring unit 113 has a time measuring function has been described, but the time measuring unit 113 may have a timer function. In this case, the process is simplified.

FIG. 2 is a block diagram illustrating an example of a schematic configuration of a printer according to the present invention. FIG. 3 is a perspective view of a printer showing an example of arrangement positions of a fixing temperature sensor and an in-machine temperature sensor. FIG. 2 is a functional configuration diagram illustrating an example of a main part of a printer. These are graphs showing an example of changes in the in-machine temperature TI, the fixing temperature TB, and the ambient temperature TA. These are the flowcharts which show an example of operation | movement of a printer (mainly CPU).

Explanation of symbols

100 Printer 11 CPU
111 In-machine temperature detector (part of in-machine temperature detector)
112 Temperature update unit (temperature update means)
113 Timekeeping section (timekeeping means)
114 2nd determination part (2nd determination means)
115 Fixing temperature detection unit (part of fixing temperature detection means)
116 3rd determination part (3rd determination means)
117 1st determination part (1st determination means)
118 Correction part (part of correction means)
12 RAM
121 temperature storage unit 122 date and time storage unit 4 print processing unit 43 fixing unit 431 fixing temperature sensor (part of fixing temperature detecting means)
431a Non-contact temperature sensor 431b Contact temperature sensor 432 Heating unit 44 Conveyance control unit (part of correction means)
5 In-machine temperature sensor 6 Fan

Claims (7)

An image forming apparatus that heat-fixes a toner image transferred to a recording paper via a fixing unit to form an image on the recording paper,
An in-machine temperature detecting means for detecting an in-machine temperature that is an atmospheric temperature in the image forming apparatus;
Based on the in-machine temperature detected by the in-machine temperature detection means, it is determined whether or not an ambient temperature, which is an external atmospheric temperature in which the image forming apparatus is disposed, is equal to or lower than a preset first threshold temperature. First determination means for determining;
Correction means for correcting a set value of the fixing temperature in the fixing unit when the first determining means determines that the ambient temperature is equal to or lower than a first threshold temperature;
Temperature storage means for storing the in-machine temperature;
When an instruction to start printing is received, a temperature updating unit that records a start internal temperature that is an internal temperature detected via the internal temperature detection unit in the temperature storage unit;
Date and time storage means for storing date and time information;
A time measuring unit that has a time measuring function, measures the date and time when the printing process is terminated, and records date and time information in the date and time storage unit;
When an instruction to start printing is received, a period between the date and time when the instruction is received and the date and time information at the end of the previous printing process stored in the date and time storage unit Second determination means for determining whether or not a certain pause period is equal to or less than a preset threshold period;
Equipped with a,
The first determination means includes
A start internal temperature which is an internal temperature detected via the internal temperature detection means when an instruction to start printing is received is equal to or lower than a preset second threshold temperature; and
The starting internal temperature at the time of the previous printing process stored in the temperature storage means is less than or equal to a preset third threshold temperature, and the pause period is less than or equal to the preset threshold period by the second determination means. If it is determined that there is
An image forming apparatus that determines that the ambient temperature is equal to or lower than the first threshold temperature .   The correction unit corrects a set value of a conveyance speed of the recording paper in the fixing unit when the first determination unit determines that the ambient temperature is equal to or lower than a first threshold temperature. Item 2. The image forming apparatus according to Item 1.   The correction unit is a time period from when an instruction to start printing is received to when a printing operation is started when the first determination unit determines that the ambient temperature is equal to or lower than a first threshold temperature. The image forming apparatus according to claim 1, wherein a set value of a certain waiting time is corrected. The image forming apparatus according to claim 1, wherein the second threshold temperature is set to be substantially the same temperature as the first threshold temperature. The image forming apparatus according to claim 1, wherein the third threshold temperature is set to be substantially the same temperature as the first threshold temperature. Fixing temperature detecting means for detecting a fixing temperature of the fixing unit;
Third determination means for determining whether or not the fixing temperature detected by the fixing temperature detection means at the time when an instruction to start printing is received is equal to or lower than a preset fourth threshold temperature;
With
In the first determination unit, a start internal temperature at the time of the previous printing process stored in the temperature storage unit is equal to or lower than a preset third threshold temperature, and the fixing temperature is set by the third determination unit. 6. The image formation according to claim 1, wherein when it is determined that the temperature is equal to or lower than the fourth threshold temperature, the atmosphere temperature is determined to be equal to or lower than the first threshold temperature. apparatus. The image forming apparatus according to claim 6, wherein the fourth threshold temperature is set to an in-machine temperature detected by the in-machine temperature detection unit when an instruction to start printing is received. .

Images