JP2012230146A - Cooling mechanism and cooling mechanism mounting device having cooling mechanism mounted thereon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress power consumption and noise.SOLUTION: A control section drives a cooling section in a low-efficiency cooling state (S105), and later, even if a detected temperature T reaches a switching threshold temperature (a first threshold temperature Tth1) ("Yes" in S115), when a temperature (a temperature Ta when fishing a fan low-speed printing) in finishing the processing in the low-efficiency cooling state is an upper limit threshold temperature (a second threshold temperature Tth2) or less ("No" in S130), retains the low-efficiency cooling state (S135) without changing the cooling state of the cooling section to a high-efficiency cooling state.

Description

  The present invention relates to a cooling mechanism that cools an object to be cooled, and a cooling mechanism mounting device that mounts the cooling mechanism.

  For example, various apparatuses such as an image forming apparatus and a projector include a cooling mechanism therein. The cooling mechanism is a mechanism that uses various heating elements as objects to be cooled and cools the objects to be cooled by a cooling unit such as a cooling fan. The cooling mechanism includes a temperature detection unit that detects the temperature of the object to be cooled, and a device that switches the driving of the cooling fan according to the detected temperature detected by the temperature detection unit (for example, Patent Document 1).

  In the cooling mechanism disclosed in Patent Document 1 (hereinafter referred to as “conventional cooling mechanism”), two temperatures are set, and the cooling fan is stopped until the detected temperature reaches the first set temperature, When the detected temperature reaches the first set temperature, the cooling fan is driven to rotate at a low speed, and when the detected temperature reaches the second set temperature, the cooling fan is driven to rotate at a high speed.

  When the detected temperature reaches a predetermined temperature (here, the second set temperature), the conventional cooling mechanism qualitatively switches the rotation speed of the cooling fan from low speed to high speed. At this time, in the cooling mechanism, since the cooling fan always rotates at high speed, power consumption and noise increase.

JP-A-8-217163 (paragraphs 27 and 30)

  The conventional cooling mechanism has a problem that power consumption and noise tend to increase because the rotation speed of the cooling fan is qualitatively switched when the detected temperature reaches a predetermined temperature.

  In this regard, the inventor switches the rotation speed of the cooling fan to a high speed when the switching timing of the rotation speed of the cooling fan can be delayed even when the detected temperature reaches a predetermined temperature. However, it was considered that if the low speed is maintained, the driving time of the cooling fan at a high speed can be shortened, thereby suppressing power consumption and noise.

  In the conventional cooling mechanism, for example, a Peltier element or the like can be used as the cooling unit instead of the cooling fan. However, even in this configuration, the conventional cooling mechanism qualitatively switches from the low cooling efficiency state to the normal cooling state with high cooling efficiency and the rapid cooling state with high cooling efficiency when the detected temperature reaches a predetermined temperature. Power increases. In the case of this configuration, the inventor, if the switching timing of the driving state of the Peltier element can be delayed, if the driving state of the Peltier element is not switched and the normal cooling state is maintained, the inventor suddenly It was considered that the driving time of the Peltier element in the cooled state can be shortened, and thereby power consumption can be suppressed.

  The present invention has been made to solve the above-described problems, and has as its main object to provide a cooling mechanism that suppresses power consumption and a cooling mechanism mounting device that mounts the cooling mechanism.

  In order to achieve the object, the first invention is a cooling mechanism for cooling a cooling object, a cooling unit for cooling the cooling object, and a temperature detection unit for detecting the temperature of the cooling object as a detection temperature. And a control unit that switches the cooling state of the cooling unit to any one of a low-efficiency cooling state with low cooling efficiency and a high-efficiency cooling state with higher cooling efficiency than the low-efficiency cooling state, and at least the cooling unit A storage unit that stores a switching threshold temperature used as a reference temperature for switching the cooling state of the vehicle from the low-efficiency cooling state to the high-efficiency cooling state, and an upper-limit threshold temperature used as a temperature of an upper limit value of temperature control The control unit causes the cooling unit to be driven in the low-efficiency cooling state, and after that, even if the detected temperature reaches the switching threshold temperature, the low-efficiency When the temperature at the end of processing in the cooling state is below the upper threshold temperature, the cooling state of the cooling unit without switching to the high efficiency cooling conditions, a configuration that maintains leave the low-efficiency cooling state.

  Here, the “low-efficiency cooling state” means, for example, a state where the cooling fan is driven at a low speed when the cooling unit is configured by a single cooling fan, When the cooling unit is composed of a plurality of cooling fans, it means “a state where a single cooling fan is driven”. In addition, the “highly efficient cooling state” means, for example, a state in which the cooling fan is driven at a high speed when the cooling unit is configured by a single cooling fan. This means “a state in which a plurality of cooling fans are driven” when the section is composed of a plurality of cooling fans.

  Note that the cooling unit can be configured by, for example, a Peltier element instead of the cooling fan. In this case, the “low efficiency cooling state” means a normal cooling state, and the “high efficiency cooling state” means a rapid cooling state.

  Even when the detected temperature reaches the switching threshold temperature, this cooling mechanism sets the cooling state of the cooling unit to high-efficiency cooling when the temperature at the end of processing in the low-efficiency cooling state is equal to or lower than the upper-limit threshold temperature. It is configured to maintain the low-efficiency cooling state without switching to the state. Therefore, this cooling mechanism can shorten the drive time of the cooling unit in the high-efficiency cooling state, and can thereby reduce power consumption.

  Moreover, 2nd invention is a cooling mechanism mounting apparatus which mounts the cooling mechanism which cools a cooling target object, Comprising: It is set as the structure which mounts the cooling mechanism which concerns on 1st invention.

  This cooling mechanism mounting apparatus is configured to use the cooling mechanism according to the first invention for cooling the object to be cooled. Therefore, this cooling mechanism mounting apparatus can shorten the drive time of the cooling unit in the high-efficiency cooling state, thereby suppressing power consumption.

According to the first invention, a cooling mechanism that suppresses power consumption can be provided.
Further, according to the second invention, it is possible to provide a cooling mechanism mounting apparatus that uses the cooling mechanism according to the first invention for cooling the object to be cooled.

It is a figure which shows the structure of the cooling mechanism mounting apparatus which concerns on Embodiment 1. FIG. It is a figure which shows the structure of the cooling mechanism which concerns on Embodiment 1. FIG. It is a figure which shows the cooling operation of the cooling mechanism which concerns on a comparative example. FIG. 6 is a diagram (1) illustrating a cooling operation of the cooling mechanism according to the first embodiment. FIG. 6B is a diagram (2) illustrating the cooling operation of the cooling mechanism according to the first embodiment. It is a flowchart (1) which shows operation | movement of the cooling mechanism which concerns on Embodiment 1. FIG. It is a flowchart (2) which shows operation | movement of the cooling mechanism which concerns on Embodiment 1. FIG. It is a figure which shows the structure of the cooling mechanism which concerns on Embodiment 2. FIG. FIG. 6A is a diagram (1) illustrating a cooling operation of a cooling mechanism according to a second embodiment. FIG. 6B is a diagram (2) illustrating a cooling operation of the cooling mechanism according to the second embodiment. 6 is a flowchart showing the operation of the cooling mechanism according to the second embodiment.

  Hereinafter, an embodiment of the present invention (hereinafter referred to as “the present embodiment”) will be described in detail with reference to the drawings. Each figure is only schematically shown so that the present invention can be fully understood. Therefore, the present invention is not limited to the illustrated example. Moreover, in each figure, the same code | symbol is attached | subjected about the common component and the same component, and those overlapping description is abbreviate | omitted.

[Embodiment 1]
<Configuration of cooling mechanism mounted device>
Hereinafter, the configuration of the cooling mechanism mounting apparatus according to the first embodiment will be described with reference to FIG. FIG. 1 is a diagram illustrating a configuration of the cooling mechanism mounting device according to the first embodiment.

  The present invention provides a cooling mechanism 100 (see FIGS. 1 and 2) that shortens the drive time of a cooling unit (in the first embodiment, a cooling fan 110 (see FIG. 2) described later) in a highly efficient cooling state. This is the main purpose. For this purpose, the present invention is mainly characterized in that the cooling mechanism 100 is operated as described in the following (1), and further is operated as described in the following (2).

  (1) The cooling mechanism 100 sets the temperature of the cooling target detected by a temperature detection unit 121e (see FIG. 2), which will be described later, to “detected temperature T”, and changes the cooling state of the cooling unit from the low-efficiency cooling state to the high-efficiency cooling. The temperature used as the reference for switching to the state is referred to as “switching threshold temperature”, and the temperature used as the upper limit value of the temperature control is referred to as “upper threshold temperature”. Then, as shown in FIG. 4A, the cooling mechanism 100 ends the process in the low-efficiency cooling state even when the detected temperature T reaches the “switching threshold temperature (first threshold temperature Tth1 described later)”. When the temperature at the time (low-efficiency job end temperature Ta described later) is equal to or lower than the “upper limit threshold temperature (second threshold temperature Tth2 described later)”, the cooling unit (the cooling fan 110 described later in the first embodiment) Instead of switching the cooling state to the high efficiency cooling state, the low efficiency cooling state is maintained.

  (2) As shown in FIG. 4B, the cooling mechanism 100 finishes the process in the low-efficiency cooling state when the detected temperature T reaches the “switching threshold temperature (first threshold temperature Tth1 described later)”. When the temperature at the time (low-efficiency job end temperature Ta described later) exceeds the “upper threshold temperature (second threshold temperature Tth2 described later)”, the cooling state of the cooling unit is switched to the high-efficiency cooling state. In this case, however, the cooling mechanism 100 preferably switches the state of the cooling unit from the low efficiency cooling state to the high efficiency cooling state when the detected temperature T reaches a switching temperature Tc described later.

  A cooling mechanism mounting apparatus 1 shown in FIG. 1 is an apparatus on which such a cooling mechanism 100 is mounted. Here, the cooling mechanism mounting apparatus 1 will be described assuming an image forming apparatus that forms an image by an electrophotographic process, particularly a tandem color printer. Hereinafter, the cooling mechanism mounting apparatus 1 is referred to as a “color printer 1”. However, the cooling mechanism mounting apparatus 1 may be an apparatus configured to cool an object to be cooled by the cooling mechanism 100. For example, there may be various types of apparatuses other than the image forming apparatus such as a projector.

  In the first embodiment, since the cooling mechanism mounting apparatus 1 is configured as the “color printer 1”, “job” described later means “printing”. However, for example, when the cooling mechanism mounting apparatus 1 is configured as a “projector”, a “job” described later means “projection of (image)”. As described above, when the cooling mechanism mounting apparatus 1 is configured as an apparatus other than the image forming apparatus, a “job” described later means a function realized by the apparatus.

  As shown in FIG. 1, a color printer 1 as a cooling mechanism mounting device includes a main body 2 that houses main components and a top cover 3 that can be opened and closed with respect to the main body 2. ing.

The main body 2 includes a display operation unit 2a and a discharge stacker unit 2b.
The display operation unit 2a is a component for performing display of various information and input of various instructions by the user. Here, it is assumed that the display operation unit 2a includes a liquid crystal display panel, a switch, and the like.
The discharge stacker unit 2b is a stacking unit from which the print medium P is finally discharged. The print medium P is a medium on which an image is printed by the color printer 1.

  The main body 2 includes a print medium storage unit 4, a conveyance path 5, a conveyance belt 8, an image forming unit 10, an exposure unit 20, a transfer unit 30, and a fixing unit 40 inside.

The print medium storage unit 4 is a storage unit that stores the print medium P. The print medium storage unit 4 can store a plurality of print media P.
The conveyance path 5 is a path through which the print medium P is conveyed. The conveyance path 5 is provided from the print medium storage unit 4 to the discharge stacker unit 2b. Here, the terms defining the positions such as “upstream”, “downstream”, and “front” are based on the conveyance direction of the print medium P.

A large number of rollers 6 are arranged around the conveyance path 5. In FIG. 1, as the roller 6, a paper feed roller 6a, a first registration roller 6b, and a second registration roller 6c are shown.
The paper feed roller 6 a is a roller for feeding the print media P one by one from the print media storage unit 4.
The first registration roller 6 b and the second registration roller 6 c are rollers for transporting the print medium P fed from the print medium storage unit 4 to the image forming unit 10.
The rollers 6a, 6b, and 6c together with the transport belt 8 constitute a transport unit 50 (see FIG. 2) that transports the print medium P.

  A large number of sensor units SN are arranged around the transport path 5. In FIG. 1, the first transport sensor SN1, the second transport sensor SN2, the writing sensor SN3, and the discharge sensor SN4 are shown as the sensor unit SN.

  Each of the sensors SN1, SN2, SN3, and SN4 is a traveling system sensor for detecting that the print medium P has reached the installation position of each sensor. The first transport sensor SN1 is provided at a position in front of the first registration roller 6b. The second transport sensor SN2 is provided at a position in front of the second registration roller 6c. The writing sensor SN3 is provided at a position after the second registration roller 6c. The discharge sensor SN4 is provided at a position after the fixing unit 40.

  Each of the sensors SN1, SN2, SN3, and SN4 outputs a detection signal having a unique value to the control unit 120 (see FIG. 2) according to the presence or absence of the print medium P. The control unit 120 specifies the position of the print medium P according to the value of the detection signal input from each sensor SN1, SN2, SN3, SN4. In particular, the control unit 120 detects the timing at which the print medium P reaches the image forming unit 10 based on the detection signal input from the writing sensor SN3. Further, the control unit 120 detects that the print medium P is discharged to the discharge stacker unit 2b based on a detection signal input from the discharge sensor SN4.

  A part of the conveyance path 5 is constituted by a conveyance belt 8. The transport belt 8 is a transport unit that transports the fed print medium P toward the downstream side of the transport belt 8. An image forming unit 10 and an exposure unit 20 are provided on the conveyance belt 8. A transfer roller 31 as a transfer unit 30 is provided on the inner periphery of the transport belt 8. Further, a fixing unit 40 is provided downstream of the conveyance belt 8. The image forming unit 10, the exposure unit 20, the transfer unit 30, and the fixing unit 40 are well-known components, and are characteristic portions of the present invention (particularly, the temperature control (1) of the cooling mechanism 100 described above). Here, only the outline will be described.

The image forming unit 10 is a component that forms an image on the surface of the photosensitive drum 12 provided inside. The image forming unit 10 includes a developer storage unit 11 and a photosensitive drum 12 therein.
The developer storage unit 11 is a storage unit that stores a developer such as toner.
The photosensitive drum 12 is an image carrier on which an electrostatic latent image and a developer image are formed.

  The surface of the photosensitive drum 12 of the image forming unit 10 is uniformly charged by a charging member (not shown) and then partially exposed by the exposure unit 20 to form an electrostatic latent image on the surface. Thereafter, the developer stored in the developer storage unit 11 is supplied to the photosensitive drum 12 by a developing member (not shown). As a result, the electrostatic latent image is developed on the surface of the photosensitive drum 12 as a developer image.

  The image forming unit 10 is configured to be freely attached to and detached from the main body unit 2. In the example shown in FIG. 1, the color printer 1 includes four image forming units 10 corresponding to the respective colors of black (K), yellow (Y), magenta (M), and cyan (C). It has been. The four image forming units 10 have the same configuration except that the color of the developer stored in the developer storage unit 11 is different. Hereinafter, when distinguishing components corresponding to each color of black (K), yellow (Y), magenta (M), and cyan (C), an alphabetic character is added at the end of the code given to each component. The description will be given with “K”, “Y”, “M”, and “C”.

  The exposure unit 20 is a component that partially exposes the surface of the photosensitive drum 12 based on a print command transmitted from a host device (not shown). The surface of the photosensitive drum 12 is uniformly charged by a charging member (not shown), and then partially exposed by the exposure unit 20, whereby an electrostatic latent image is formed on the surface. Here, the description will be made assuming that the exposure unit 20 is configured as an LED head. Hereinafter, the exposure unit 20 is referred to as “LED head 20”. The LED head 20 is provided on the top cover 3 and is connected to a control unit 120A (see FIG. 2) and a power supply unit 200 (see FIGS. 1 and 2) of the main body 2 by a cable (not shown). The LED head 20 is disposed near the surface of the photosensitive drum 12 when the top cover portion 3 is closed. In the first embodiment, four LED heads 20 are provided corresponding to the photosensitive drums 12K, 12Y, 12M, and 12C of the respective colors.

  The transfer unit 30 is a component that transfers the developer image formed on the surface of the photosensitive drum 12 to the print medium P. The transfer unit 30 includes a transfer roller 31. The transfer roller 31 is provided on the inner periphery of the conveyance belt 8 so as to face the photosensitive drum 12. The transfer roller 31 draws the developer image from the photosensitive drum 12 toward the conveyance belt 8 when a high voltage having a polarity opposite to the polarity of the developer image formed on the surface of the photosensitive drum 12 is applied. At that time, the developer belt is transferred onto the print medium P by the transport belt 8 transporting the print medium P. In the first embodiment, four transfer rollers 31 are provided corresponding to the photosensitive drums 12K, 12Y, 12M, and 12C of the respective colors.

  The fixing unit 40 heats and pressurizes the print medium P on which the developer image is transferred by a heat roller (not shown) and a pressure roller (not shown) provided therein, thereby generating a developer image. It is a component that melts and fixes the developer image on the print medium P.

  The image forming unit 10, the exposure unit 20, the transfer unit 30, and the fixing unit 40, together with the conveyance unit 50 (rollers 6 a, 6 b, 6 c, and the conveyance belt 8), have an image forming mechanism 60 (see FIG. 2). It is composed.

  The color printer 1 has a cooling mechanism 100. The cooling mechanism 100 is a mechanism that cools a cooling target object using various heating elements such as a power supply unit 200 that supplies power to each part and a heat roller (not shown) of the fixing unit 40 as a cooling target object. Here, the cooling mechanism 100 will be described on the assumption that the power supply unit 200 is cooled. In the first embodiment, the power supply unit 200 includes a first output power supply unit 200a, a second output power supply unit 200b, and a third output power supply unit 200c. The first output power supply unit 200a, the second output power supply unit 200b, and the third output power supply unit 200c have a power supply voltage of 3.3 (V), 5 (V), and 24 (V), respectively. Is applied to the control unit 120 (see FIG. 2).

<Configuration of cooling mechanism>
Hereinafter, the configuration of the cooling mechanism 100 will be described with reference to FIG. FIG. 2 is a diagram illustrating the configuration of the cooling mechanism according to the first embodiment.

  As shown in FIG. 2, the cooling mechanism 100 includes a cooling unit 110. The cooling unit 110 is a component that cools the object to be cooled (here, the power supply unit 200). Here, the cooling unit 110 will be described on the assumption that it is configured by a single cooling fan. Hereinafter, the cooling unit 110 is referred to as a “cooling fan 110”.

  The cooling fan 110 is driven at a low speed (hereinafter referred to as “fan stop state”) or at a low speed (hereinafter referred to as “fan low speed drive”) by the fan control unit 121a of the control unit 120. The state is called “state”) and the state is being driven at high speed (hereinafter referred to as “fan high-speed drive state”). The cooling efficiency (cooling speed) of the cooling fan 110 is proportional to the rotational speed of the cooling fan 110. Therefore, the cooling state of the cooling fan 110 is “stopped” when “fan stopped”, “low efficiency cooled” when “fan low speed driving”, and “high efficiency cooling” when “fan high speed driving”. It becomes.

Here, “low speed” is the rotational speed when the cooling fan 110 is driven by a power supply voltage of DC12 (± 10%) (Volt; V).
The “high speed” is the rotational speed when the cooling fan 110 is driven with a power supply voltage of DC24 (± 10%) (V). When the fan is in the high speed driving state, the noise during driving is larger and the power consumption is larger than in the fan low speed driving state.

  The cooling fan 110 is provided in the power supply unit 200 or around the power supply unit 200. The power supply unit 200 includes a heat sink (not shown) and a thermistor 220 for temperature detection. The thermistor 220 is attached to a heat sink (not shown).

  The cooling fan 110 is connected to the control unit 120. The control unit 120 is a control unit that controls the operation of each unit of the color printer 1. The control unit 120 includes an MPU 121, a fan rotation speed changing circuit 141, an operational amplifier (Operational Amplifier) 142, a voltage dividing resistor 143, and an A / D converter 144. The external interface 151, the storage unit 161, The display operation unit 2a, the image forming mechanism 60 described above, and the sensor unit SN described above are connected.

  The MPU 121 is a calculation execution unit that executes various calculations. The MPU 121 executes a control program stored in advance in the storage unit 161, thereby enabling a fan control unit 121a, a temperature increase rate calculation unit 121b, a print end temperature calculation unit 121c, a time calculation unit 121d, a temperature detection unit 121e, and The fan speed switching temperature calculation unit 121f functions. However, the MPU 121 also functions as a means for analyzing a print command and acquiring image data to be printed and a means for driving the image forming mechanism 60 by executing a control program. There is a low relevance to the characteristic part of the present invention, and the description is omitted here.

The fan control unit 121 a is a functional unit that controls the rotation speed of the cooling fan 110.
The temperature increase rate calculation unit 121b is a functional unit that calculates the temperature increase rate k1 in the fan low speed drive state F1 (see FIGS. 4A and 4B).

  The printing end temperature calculation unit 121c is a temperature at the end of printing when the rotation speed of the cooling fan 110 is maintained at a low speed (hereinafter referred to as “fan low speed printing end temperature”) Ta (FIGS. 4A and 4B). (See FIG. 4B) and a temperature at the end of printing when the rotation speed of the cooling fan 110 is switched from low speed to high speed (hereinafter referred to as “fan high temperature printing end temperature”) Tb. It is. “Fan low-speed printing end temperature Ta” and “Fan high-speed printing end temperature Tb” are respectively set to “low-efficiency cooling job” when the cooling mechanism-equipped device 1 is a device that realizes functions other than printing processing. End temperature Ta ”and“ High efficiency cooling job end temperature Tb ”.

  The time calculation unit 121d determines the time (hereinafter referred to as “switching threshold arrival time”) that has reached a switching threshold temperature (here, a first threshold temperature Tth1 (see FIGS. 3, 4A, and 4B described later)). This is a functional means for calculating t1.

  The temperature detection unit 121e is a functional unit that detects the temperature of the object to be cooled (here, the power supply unit 200). Here, the temperature of the cooling object detected by the temperature detector 121e is referred to as “detected temperature T”.

  The fan speed switching temperature calculation unit 121f is a reference temperature (hereinafter referred to as “switching”) for actually switching the state of the cooling fan 110 from the fan low speed driving state (low efficiency cooling state) to the fan high speed driving state (high efficiency cooling state). This is a functional means for calculating Tc).

The fan rotation speed change circuit 141 is a circuit for changing the state of the cooling fan 110 to any one of the fan stop state, the fan low speed drive state, and the fan high speed drive state.
The operational amplifier 142 is a DC amplifier that amplifies the difference between the inputs to the two input terminals.
The voltage dividing resistor 143 is a resistor that divides the power supply voltage 3.3 (V) with the thermistor 220.
The A / D converter 144 has a function of converting an analog input value into a digital value every predetermined time and outputting the digital value. The A / D converter 144 converts a detection voltage value, which is an analog value input from the thermistor 220 via the operational amplifier 142, into a digital value. The detected temperature voltage value, which is a value, is converted and output to the MPU 121.
The external interface 151 is an interface that communicates with a host device (not shown).

  The storage unit 161 is a storage unit that stores various data necessary for controlling the cooling fan 110, a control program, and the like. The storage unit 161 preferably has a plurality of storage areas, for example, the first storage unit 161a in which data whose value frequently changes (hereinafter referred to as “variable data”) is stored, and the value does not frequently change. Data (hereinafter referred to as “fixed data”) may be partitioned into a second storage unit 161b in which data is stored in advance. The first storage unit 161a and the second storage unit 161b may be configured by a single storage unit or may be configured by a plurality of storage units.

  For example, data such as “switching threshold temperature” and “upper threshold temperature” is stored in the first storage unit 161a. In the first embodiment, the “switching threshold temperature” corresponds to “first threshold temperature Tth1 (see FIGS. 3, 4A, and 4B)”. The “upper threshold temperature” corresponds to “second threshold temperature Tth2 (see FIGS. 4A and 4B)”. However, here, the cooling mechanism 100 sets the “switching threshold temperature” and the “upper threshold temperature” so that the switching timing of the cooling fan 110 from the low efficiency cooling state to the high efficiency cooling state can be delayed as much as possible. The configuration is used as variable data. However, the cooling mechanism 100 may be configured to use the “switching threshold temperature” and the “upper threshold temperature” as fixed data depending on the operation.

The “first threshold temperature Tth1” is a threshold temperature used to detect the timing of switching the state of the cooling fan 110 from the fan low-speed driving state (low-efficiency cooling state) to the fan high-speed driving state (high-efficiency cooling state). is there.
The “second threshold temperature Tth2” is the upper limit temperature (saturation temperature) of the thermistor 220 detected at the end of the printing process when the state of the cooling fan 110 is switched from the fan low-speed driving state to the fan high-speed driving state. is there. The cooling target (here, the power supply unit 200) has a temperature at the end of the printing process (hereinafter referred to as “printing end temperature Tend (see FIGS. 3, 4A, and 4B))” as the second threshold temperature. When it is Tth2 or less, it is assumed that no failure or characteristic change occurs.

  Further, in the second storage unit 161b, for example, “temperature increase rate k2 in the fan high-speed drive state F2 (see FIGS. 4A and 4B)”, “thermistor voltage-temperature conversion table D1 (not shown)”, Data such as “waiting time twa (see FIGS. 3, 4A, and 4B)” is stored in advance. The “temperature increase rate k2 in the fan high-speed drive state F2” represents the temperature increase rate in the fan high-speed drive state F2 measured in advance. The “thermistor voltage-temperature conversion table D1” is table data that defines the relationship between the voltage value detected by the thermistor 220 and the temperature corresponding to the voltage value. The “standby time twa” represents the time from the start to the end of the standby process. The standby time twa is also a power save transition time. The standby process is executed after printing is completed.

  The MPU 121 of the control unit 120 receives a voltage applied to the thermistor 220 of the power supply unit 200 via an operational amplifier 142 and an A / D converter 144 as buffers. Then, in the MPU 121, the temperature detection unit 121 e refers to the “thermistor voltage-temperature conversion table D 1 (not shown)” stored in the storage unit 161 in advance, and based on the input voltage value, the power supply unit 200. Is detected as a detection temperature T. In the MPU 121, the fan control unit 121 a controls the fan rotation speed changing circuit 141 based on the detected temperature T, and changes the rotation speed of the cooling fan 110.

<Operation of cooling mechanism>
Hereinafter, the operation of the cooling mechanism will be described with reference to FIGS. 3, 4A, and 4B. Here, in order to explain the operation of the cooling mechanism 100 in an easy-to-understand manner, first, the operation of the comparative example that performs the same operation as the conventional cooling mechanism will be described with reference to FIG. 3, and then, FIG. 4A and FIG. The operation of the cooling mechanism 100 according to the first embodiment will be described with reference to 4B.

  FIG. 3 is a diagram illustrating the operation of the cooling mechanism according to the comparative example. 4A and 4B are diagrams illustrating the operation of the cooling mechanism according to the first embodiment. 3, 4A, and 4B are graphs showing changes in the temperature of the object to be cooled (here, the power supply unit 200) accompanying the control of the cooling state of the cooling fan 110, respectively. In addition, FIG. 3, FIG. 4A and FIG. 4B have shown the change of temperature with the linear graph. However, the change in temperature actually changes non-linearly. 3, 4 </ b> A, and 4 </ b> B, in the color printer 1, the fan low-speed driving state (low-efficiency cooling state) is expected to be about 1 minute, and the time is short. Show.

  Here, since the cooling mechanism-equipped device is configured as the color printer 1, the state of the device changes in the order of “printing (during job)”, “standby”, and “power saving”. Will be described. When the state of the apparatus is “printing”, the cooling object is in a “high heat generation state”. Further, when the state of the apparatus is “standby”, the object to be cooled becomes “low heat generation state”. Further, when the state of the apparatus is “power saving”, the object to be cooled is “low heat generation or stopped”.

  Note that when the printing process ends, the color printer 1 shifts the state of the apparatus to a standby state and starts the standby process. The time from the start to the end of the standby process is preset as “standby time twa” and stored in the storage unit 161. Here, “standby time twa” is set to “60” (Second; S), for example.

  Here, the cooling mechanism according to the comparative example is referred to as “cooling mechanism 100a (not shown)”, the cooling fan 110 is referred to as “cooling fan 110a (not shown)”, and the cooling mechanism mounting device on which the cooling mechanism 100a is mounted. Will be described as “color printer 1a (not shown)”. Further, the cooling mechanism 100 according to the first embodiment is referred to as “cooling mechanism 100A”, the cooling fan 110 is referred to as “cooling fan 110A”, and the cooling mechanism mounting apparatus 1 on which the cooling mechanism 100A is mounted is referred to as “color printer 1A”. explain. The operation of the cooling mechanism 100A shown in FIGS. 4A and 4B is executed by the control unit 120A of the cooling mechanism 100A.

  As shown in FIG. 3, the cooling mechanism 100a according to the comparative example performs temperature control indicated by a one-dot chain line L0 on the object to be cooled.

  That is, when the color printer 1a starts printing, the cooling mechanism 100a starts driving in the fan low speed driving state (low efficiency cooling state) F1. At this time, the detected temperature T starts to rise at a temperature rise rate k1 in the fan low-speed drive state F1 from the temperature at the start of printing (hereinafter referred to as “printing start temperature Tst”).

  When the detected temperature T reaches the first threshold temperature Tth1, the cooling mechanism 100a changes the state of the cooling fan 110a from the fan low speed driving state (low efficiency cooling state) F1 to the fan high speed driving state (high efficiency cooling state) F2. Switch. As a result, the detected temperature T continues to rise, but the rate of increase decreases from the temperature increase rate k1 in the fan low-speed drive state F1 to the temperature increase rate k2 in the fan high-speed drive state F2.

  When the printing process is completed, the color printer 1a shifts the state of the apparatus to the standby state and starts the standby process. The cooling mechanism 100a maintains the state of the cooling fan 110a in the fan high-speed driving state (high efficiency cooling state) F2 even during standby. The detected temperature T reaches the temperature Tend at the end of printing at the end of printing, and then gradually decreases as the standby process starts. In the comparative example, the print end temperature Tend is equal to the fan high-speed print end temperature Tb.

  Then, the color printer 1a starts the power saving process when the standby time twa elapses after the standby process is started. At this time, the cooling mechanism 100a switches the state of the cooling fan 110a from the fan high-speed drive state (high efficiency cooling state) F2 to the fan stop state Fsp. As a result, the detected temperature T continues to decrease, but its decreasing rate decreases.

  In contrast, as shown in FIGS. 4A and 4B, the cooling mechanism 100A according to the first embodiment performs temperature control indicated by a two-dot chain line L1 or L2 on the object to be cooled.

  That is, as shown in FIGS. 4A and 4B, when the color printer 1A starts printing, the cooling mechanism 100A starts driving in the fan low-speed driving state (low efficiency cooling state) F1. At this time, the detected temperature T starts to rise from the temperature Tst at the start of printing at a temperature rise rate k1 in the fan low speed driving state F1.

  When the detected temperature T reaches the first threshold temperature Tth1, the cooling mechanism 100A determines whether or not the predicted fan low-speed printing end temperature (low-efficiency cooling job end temperature) Ta exceeds the second threshold temperature Tth2. Is determined (see S130 of FIG. 5A).

  In this determination, as shown in FIG. 4A, when it is determined that the predicted fan low-speed printing end temperature Ta does not exceed the second threshold temperature Tth2 (that is, the predicted fan low-speed printing end temperature Ta is the first temperature The cooling mechanism 100A performs temperature control indicated by a two-dot chain line L1 in FIG. 4A when the temperature becomes equal to or lower than the two threshold temperatures Tth2 (when it is determined that “Ta ≦ Tth2”).

  That is, the cooling mechanism 100A maintains the state of the cooling fan 110A in the fan low-speed driving state (low-efficiency cooling state) F1 without switching to the fan high-speed driving state (high-efficiency cooling state) F2 (FIG. 5A). (See S135). As a result, the detected temperature T continues to rise while maintaining the temperature rise rate k1 in the fan low-speed drive state F1.

  When the printing process is completed, the color printer 1A shifts the state of the apparatus to the standby state and starts the standby process. At this time, the cooling mechanism 100A maintains the state of the cooling fan 110A in the fan low speed driving state (low efficiency cooling state) F1. Alternatively, at this time, the cooling mechanism 100A may switch the state of the cooling fan 110A from the fan low speed driving state (low efficiency cooling state) F1 to the fan high speed driving state (high efficiency cooling state) F2 according to operation. Good. The detected temperature T reaches the temperature Tend at the end of printing at the end of printing, and then gradually decreases as the standby process starts. In the first embodiment, when “Ta ≦ Tth2”, the printing end temperature Tend is equal to the fan low-speed printing end temperature Ta (see FIG. 4A).

  Then, the color printer 1A starts the power saving process when the standby time twa elapses after the standby process is started. At this time, the cooling mechanism 100A switches the state of the cooling fan 110A from the fan low speed driving state (low efficiency cooling state) F1 (or the fan high speed driving state (high efficiency cooling state) F2) to the fan stop state Fsp. As a result, the detected temperature T continues to decrease, but its decreasing rate decreases.

  On the other hand, as shown in FIG. 4B, it is determined whether or not the predicted fan low-speed printing end temperature (low-efficiency cooling job end temperature) Ta exceeds the second threshold temperature Tth2, as shown in FIG. 4B. When it is determined that the hourly temperature Ta (see the solid line in FIG. 4B) exceeds the second threshold temperature Tth2 (“Ta> Tth2”), the cooling mechanism 100A performs temperature control indicated by a two-dot chain line L2 in FIG. 4B. .

  That is, the cooling mechanism 100A calculates the switching temperature Tc. A method for calculating the “switching temperature Tc” will be described later. Then, until the detected temperature T reaches the switching temperature Tc, the cooling mechanism 100A does not switch the state of the cooling fan 110A to the fan high-speed driving state (high-efficiency cooling state) F2, but the fan low-speed driving state (low-efficiency). When the detected temperature T reaches the switching temperature Tc, the state of the cooling fan 110A is changed from the fan low-speed driving state (low-efficiency cooling state) F1 to the fan high-speed driving state (high-efficiency cooling state). Switch to F2 (see S150 in FIG. 5A). As a result, until the detected temperature T reaches the switching temperature Tc, the detected temperature T continues to increase with the temperature increase rate k1 in the fan low-speed driving state F1, and when the detected temperature T reaches the switching temperature Tc, The temperature rises at a temperature rise rate k2 in the fan high-speed drive state F2.

  When the printing process is completed, the color printer 1A shifts the state of the apparatus to the standby state and starts the standby process. At this time, the cooling mechanism 100A switches the state of the cooling fan 110A from the fan high speed driving state (high efficiency cooling state) F2 to the fan low speed driving state (low efficiency cooling state) F1. Alternatively, at this time, the cooling mechanism 100A may maintain the state of the cooling fan 110A in the fan high-speed driving state (high efficiency cooling state) F2 according to the operation. The detected temperature T reaches the temperature Tend at the end of printing at the end of printing, and then gradually decreases as the standby process starts. In the first embodiment, when “Ta> Tth2”, the print end temperature Tend is equal to the fan high-speed print end temperature Tb (see FIG. 4B).

  Then, the color printer 1A starts the power saving process when the standby time twa elapses after the standby process is started. At this time, the cooling mechanism 100A switches the state of the cooling fan 110A from the fan low speed driving state (low efficiency cooling state) F1 (or the fan high speed driving state (high efficiency cooling state) F2) to the fan stop state Fsp. As a result, the detected temperature T continues to decrease, but its decreasing rate decreases.

  The cooling mechanism 100A is called, for example, when the printing start temperature Tst is low or when the printing process starts and ends (hereinafter referred to as “printing end time t2 (see FIGS. 4A and 4B)”). ) Is short, and the temperature of the installation environment is low, it is likely to be in a state that “the predicted temperature Ta at the end of fan low-speed printing does not exceed the second threshold temperature Tth2”. Here, “when the temperature Tst at the start of printing is low” specifically means a case where a sufficient amount of time has passed since the previous printing process and the temperature of the cooling target has sufficiently decreased. To do. In addition, “when the print end time t2 is short” specifically means a case where the number of print jobs is small.

  On the other hand, the cooling mechanism 100A is “predicted” when, for example, the printing start temperature Tst is high, the printing end time t2 (see FIGS. 4A and 4B) is long, or the temperature of the installation environment is high. The fan low-speed printing end temperature Ta exceeds the second threshold temperature Tth2. Here, “when the temperature Tst at the start of printing is high” specifically refers to a case where time has not sufficiently elapsed since the previous printing process and the temperature of the cooling object has not sufficiently decreased. means. In addition, “when the print end time t2 is long” specifically means a case where the number of print jobs is large.

  In the example shown in FIG. 4B, the cooling mechanism 100A performs temperature control in two stages, a fan low-speed driving state (low-efficiency cooling state) F1 and a fan high-speed driving state (high-efficiency cooling state) F2. Yes. The cooling mechanism 100A performs temperature control so that the time of the fan low-speed driving state (low efficiency cooling state) F1 is as long as possible. Therefore, in this Embodiment 1, temperature control is not divided into three steps or more.

  The cooling mechanism 100A according to the first embodiment executes the process shown in FIG. 5A in order to realize the temperature control shown in FIGS. 4A and 4B. FIG. 5A is a flowchart illustrating the operation of the cooling mechanism according to the first embodiment.

  The cooling mechanism 100A stores data such as the second threshold temperature Tth2 and the temperature increase rate k2 in the fan high-speed driving state F2 in the storage unit 161 in advance. Here, the “temperature increase rate k2 in the fan high-speed driving state F2” means, for example, that the printing process for 1 minute is performed in advance in a high-temperature and high-humidity environment and the rated load state during the printing process of the apparatus. The rate of increase in temperature measured when the printer 1A is used, and the temperature measured when the color printer 1A performs printing processing for one minute under a low temperature and low humidity environment and the rated load state of the apparatus. It is assumed that it has been determined by comparing the rate of increase. Of both the rising rates, the higher rising rate is the temperature rising rate k2 in the fan high-speed driving state F2.

  The color printer 1A receives a print command from a host device (not shown) and starts print processing based on the print command. In accordance with this, the cooling mechanism 100A starts the temperature control shown in FIGS. 4A and 4B along the flow shown in FIGS. 5A and 5B. At this time, the cooling mechanism 100A stores data such as the printing speed S and the number J of print jobs of the color printer 1A in the storage unit 161.

  As shown in FIG. 5A, at the start of printing (specifically, at the start of the transport operation of the transport unit 50), the cooling mechanism 100A has the fan control unit 121a set the rotation speed of the cooling fan 110A to a low speed. Then, driving of the cooling fan 110A is started at a low speed (S105).

  At this time, the temperature detection unit 121e uses the voltage value detected by the thermistor 220 based on the “thermistor voltage-temperature conversion table D1 (not shown)” stored in advance in the storage unit 161 ( Here, the temperature of the power supply unit 200) is detected as the detected temperature T (S110). The detected temperature T at the first detection is the printing start temperature Tst (see FIGS. 4A and 4B). When the printing start temperature Tst is detected, the temperature detection unit 121e stores the printing start temperature Tst in the storage unit 161.

  After S110, the temperature detection unit 121e determines whether or not the detected temperature T has reached the first threshold temperature Tth1 (that is, whether or not the detected temperature T has increased to the first threshold temperature Tth1) (S115). ). Here, the first threshold temperature Tth1 starts printing, for example, 1/10 to 1/4 of the temperature rise value when the cooling fan 110A is driven at a low speed for 1 minute while the color printer 1A is printing. The temperature is a value added to the hourly temperature Tst. When the printing start temperature Tst is detected, the temperature detection unit 121e calculates the first threshold temperature Tth1 based on the printing start temperature Tst, and stores the calculated first threshold temperature Tth1 in the storage unit 161. . The first threshold temperature Tth1 is calculated when the printing start temperature Tst is detected without setting the first threshold temperature Tth1 to a fixed value when the printing process is continuously executed (during high-frequency printing). This is because the printing start temperature Tst is likely to fluctuate due to the influence of the temperature of the installation environment. That is, if the first threshold temperature Tth1 is set to a fixed value, the cooling mechanism 100A must immediately switch the state of the cooling fan 110A to the fan high-speed drive state (high efficiency cooling state) F2 when the printing start temperature Tst is high. This is because the period of the fan low-speed driving state (low efficiency cooling state) F1 is shortened.

  When it is determined in S115 that the detected temperature T has not reached the first threshold temperature Tth1 (in the case of “No”), the fan control unit 121a determines whether or not printing has ended (S120). ).

  If it is determined in S120 that printing has ended (in the case of “Yes”), the processing ends. In this case, the fan control unit 121a continues to drive the cooling fan 110A at a low speed.

  On the other hand, if it is determined in S120 that printing has not ended (in the case of “No”), the process returns to S110. As a result, in this case, the temperature detector 121e detects the detected temperature T again.

  When it is determined in S115 that the detected temperature T has reached the first threshold temperature Tth1 (in the case of “Yes”), the print end temperature calculation unit 121c displays “fan low speed print end temperature”. Ta "is calculated (S125).

This “fan low-speed printing end temperature Ta” is calculated as follows.
First, when the detected temperature T reaches the first threshold temperature Tth1, the time calculation unit 121d takes the time required for the detected temperature T to reach the first threshold temperature Tth1 after starting the printing process (hereinafter referred to as “switching”). For example, threshold value arrival time t1 ”) and is stored in the storage unit 161.

Further, the time calculating unit 121d refers to the printing speed S of the color printer 1A and the number J of print jobs stored in the storage unit 161, and calculates the printing end time t2 based on the following equation (1). Thus, the calculated printing end time t2 is stored in the storage unit 161.
t2 = J ÷ S (1)

Then, the printing end temperature calculation unit 121c refers to the “first threshold temperature Tth1”, “switching threshold arrival time t1”, and “printing end time t2” stored in the storage unit 161, and Based on Expression (2), “fan low-speed printing end temperature Ta” is calculated, and the calculated fan low-speed printing end temperature Ta is stored in the storage unit 161.
Ta = Tth1 + ((Tth1−Tst) ÷ t1) × (t2−t1) (2)

  After S125, the temperature detection unit 121e determines whether or not the fan low-speed printing end temperature Ta exceeds the second threshold temperature Tth2 (S130).

  When it is determined in S130 that the fan low-speed printing end temperature Ta does not exceed the second threshold temperature Tth2 (in the case of “No”), the cooling mechanism 100A performs the temperature control shown in FIG. 4A. That is, the cooling mechanism 100A performs the temperature control illustrated in FIG. 4A when it is determined that the detected temperature T does not exceed the “second threshold temperature Tth2” when the “printing end time t2” has elapsed. In this case, the fan control unit 121a keeps the cooling fan 110A driven at a low speed by keeping the rotation speed of the cooling fan 110 at a low speed without switching to a high speed (S135). Thereby, the cooling mechanism 100A finishes the temperature control of the cooling target (here, the power supply unit 200) during the printing process. Thereafter, when the printing process is completed, the color printer 1A shifts the state of the apparatus to the standby state and starts the standby process.

  On the other hand, when it is determined in S130 that the fan low-speed printing end temperature Ta exceeds the second threshold temperature Tth2 (in the case of “Yes”), the cooling mechanism 100A performs the temperature control shown in FIG. 4B. That is, the cooling mechanism 100A performs the temperature control illustrated in FIG. 4B when it is determined that the detected temperature T exceeds the “second threshold temperature Tth2” when the “printing end time t2” has elapsed. In this case, first, the fan speed switching temperature calculation unit 121f calculates a switching temperature Tc as a timing for actually switching the cooling fan 110A from the low speed to the high speed (S140).

The calculation of the “switching temperature Tc” is performed as follows.
First, the temperature increase rate calculation unit 121b refers to the “first threshold temperature Tth1”, “printing start temperature Tst”, and “switching threshold arrival time t1” stored in the storage unit 161, as follows. Based on Expression (3), the temperature increase rate k1 in the fan low-speed drive state F1 is calculated, and the calculated temperature increase rate k1 in the fan low-speed drive state F1 is stored in the storage unit 161.
k1 = (Tth1-Tst) / t1 (3)

Here, as shown in FIG. 4B, when the time from when the detected temperature T reaches the first threshold temperature Tth1 until it reaches the switching temperature Tc is “tx”, “switching temperature Tc”, “first threshold value” The relationship of the following equation (4) is established for “temperature Tth1”, “temperature rise rate k1 in fan low-speed driving state F1”, and “time tx”. “Time tx” is the time from the switching threshold arrival time t1 to the actual switching of the cooling state of the cooling fan 110A. The “time tx” is also a time during which the cooling fan 110A can be driven in the fan low-speed driving state (low efficiency cooling state) F1. Hereinafter, “time tx” is referred to as “low speed allowable time”.
Tc = Tth1 + k1 × tx (4)

Also, as shown in FIG. 4B, “second threshold temperature Tth2”, “switching temperature Tc”, “temperature increase rate k2 in fan high-speed driving state F2,” “printing end time t2,” “switching threshold reaching time” The relationship of the following formula (5) is established between “t1” and “time tx”.
Tth2 = Tc + k2 * (t2-t1-tx) (5)

Here, when Expression (4) is modified, the following Expression (4a) can be obtained as a calculation expression of tx.
tx = (Tc−Tth1) ÷ k1 (4a)

Then, by substituting equation (4a) into equation (5), the following equation (5a) can be obtained.
Tc + k2 × (t2−t1− (Tc−Tth1) ÷ k1) = Tth2 (5a)

When formula (5a) is modified, the following formula (6) can be obtained as a formula for calculating Tc.
Tc = (k1 * Tth2-k1 * k2 * (t2-t1) -k2 * Tth1) / (k1-k2) (6)

Thus, the “switching temperature Tc” is calculated.
The fan speed switching temperature calculation unit 121f calculates the switching temperature Tc based on the equation (6), and stores the calculated switching temperature Tc in the storage unit 161.

  After S140, the temperature detection unit 121e repeatedly determines whether or not the detected temperature T has reached the switching temperature Tc until the detected temperature T reaches the switching temperature Tc (S145).

  When it is determined in S145 that the detected temperature T has reached the switching temperature Tc (in the case of “Yes”), the fan control unit 121a switches the rotation speed of the cooling fan 110A from the low speed to the high speed, and performs cooling. The fan 110A is driven at high speed (S150). Thereby, the cooling mechanism 100A finishes the temperature control of the cooling target (here, the power supply unit 200) during the printing process. Thereafter, when the printing process is completed, the color printer 1A shifts to a standby process and starts the standby process.

  Thus, the cooling mechanism 100A maintains the rotational speed of the cooling fan 110A at a low speed when it is not necessary to switch the rotational speed of the cooling fan 110A to a high speed. Therefore, the cooling mechanism 100A can shorten the driving time of the cooling fan 110A in the high-efficiency cooling state F2, thereby suppressing power consumption and noise.

Note that the flow shown in FIG. 5A may be modified as shown in FIG. 5B, for example.
That is, as shown in FIG. 5B, when it is determined in S130 that the fan low-speed printing end temperature Ta does not exceed the second threshold temperature Tth2 (in the case of “No”), the printing end temperature calculation unit 121c calculates the temperature Tb at the end of fan high-speed printing (S131).

At this time, the printing end temperature calculation unit 121c stores “first threshold temperature Tth1”, “temperature increase rate k2 in the fan high-speed driving state F2”, “printing end time t2” stored in the storage unit 161, and Referring to the “switching threshold arrival time t1”, the fan high-speed printing end temperature Tb is calculated based on the following equation (7), and the calculated fan high-speed printing end temperature Tb is stored in the storage unit 161. Remember me.
Tb = Tth1 + k2 × (t2−t1) (7)

  After S131, the fan speed switching temperature calculation unit 121f uses the fan high-speed printing end temperature Tb calculated in S131 to calculate the difference between the fan low-speed printing end temperature Ta and the fan high-speed printing end temperature Tb ("Ta -Tb ") is greater than the difference (" Tth2-Ta ") between the second threshold temperature Tth2 and the fan low-speed printing end temperature Ta (" Ta-Tb> Tth2-Ta ") (S132). ).

  In step S132, the difference between the fan low-speed printing end temperature Ta and the fan high-speed printing end temperature Tb is larger than the difference between the second threshold temperature Tth2 and the fan low-speed printing end temperature Ta (“Ta−Tb> Tth2”). -Ta ") (if" Yes "), the process proceeds to S150. As a result, in S150, the fan control unit 121a switches the rotation speed of the cooling fan 110 from the low speed to the high speed, and drives the cooling fan 110A at a high speed.

  On the other hand, in the determination in S132, the difference between the fan low-speed printing end temperature Ta and the fan high-speed printing end temperature Tb is less than or equal to the difference between the second threshold temperature Tth2 and the fan low-speed printing end temperature Ta (“Ta−Tb ≦ Tth2 -Ta ") (if" No "), the process proceeds to S135. As a result, in S135, the fan control unit 121a maintains the rotation speed of the cooling fan 110 at a low speed without switching to a high speed, and continues to drive the cooling fan 110A at a low speed.

The processes of S131 and S132 shown in FIG. 5B are intended for the following temperature control.
That is, if the cooling mechanism 100A does not switch the state of the cooling fan 110A at all when the fan low-speed printing end temperature Ta does not exceed the second threshold temperature Tth2, the number of print jobs per print is small. In addition, when the printing process is continuously executed (at the time of high-frequency printing), the printing start temperature Tst becomes high in the subsequent printing process, and the state of the cooling fan 110A is immediately changed to the fan high-speed driving state (high cooling). Status) The possibility of switching to F2 increases. The cooling mechanism 100A can reduce the printing start temperature Tst in the next and subsequent printing processes by performing the processes of S131 and S132 shown in FIG. 5B during such high-frequency printing. As a result, the cooling mechanism 100A can suppress the switching frequency of the state of the cooling fan 110A during high-frequency printing.

  In the first embodiment, the case where the cooling unit 110 is configured by a single cooling fan has been described. However, the cooling unit 110 can be configured by a plurality of cooling fans. In this configuration, in the cooling mechanism 100, a state where only one cooling fan is rotationally driven is a “low efficiency cooling state”, and a state where a plurality of cooling fans are rotationally driven is a “high efficiency cooling state”. .

  As described above, according to the cooling mechanism 100A according to the first embodiment, the driving time of the cooling fan 110A in the high-efficiency cooling state (here, the fan high-speed driving state F2) can be shortened. Electric power and noise can be suppressed.

[Embodiment 2]
The cooling mechanism 100 can perform temperature control not only during the “printing” period during which the color printer 1 is performing the printing process but also during the “standby” period during which the color printer 1 is performing the standby process. . The cooling mechanism 100B according to the second embodiment is configured to perform the temperature control illustrated in FIGS. 7A and 7B during the “standby” period in which the color printer 1 performs the standby process.

<Configuration of cooling mechanism>
Hereinafter, the configuration of the cooling mechanism 100B according to the second embodiment will be described with reference to FIG. FIG. 6 is a diagram illustrating the configuration of the cooling mechanism according to the second embodiment. Here, the cooling mechanism mounting apparatus 1B on which the cooling mechanism 100B is mounted will be described assuming an image forming apparatus that forms an image by an electrophotographic process, particularly a tandem type color printer. Hereinafter, the cooling mechanism mounting apparatus 1B is referred to as a “color printer 1B”. Further, the control unit 120 of the cooling mechanism 100B will be described as a “control unit 120B”.

  As illustrated in FIG. 6, the cooling mechanism 100B is different from the cooling mechanism 100A according to the first embodiment in that the power supply unit 200 includes two cooling units 110. Hereinafter, when the two cooling units 110 are distinguished from each other, they will be described as a “first cooling unit 111” and a “second cooling unit 112”, respectively. Here, description will be made assuming that the “first cooling unit 111” and the “second cooling unit 112” are configured as cooling fans. Hereinafter, the “first cooling unit 111” and the “second cooling unit 112” are referred to as “first cooling fan 111” and “second cooling fan 112”.

  The first cooling fan 111 is connected to the fan rotation speed change circuit 141, and the rotation speed is controlled by the fan rotation speed change circuit 141 to rotate at “low speed” or “high speed”. Here, “low speed” is the rotational speed when driven by a power supply voltage of DC12 (± 10%) (V). The “high speed” is a rotation speed when driven by a power supply voltage of DC24 (± 10%) (V). The first cooling fan 111 is a component corresponding to the cooling fan 110A of the first embodiment. The cooling mechanism 100B controls the rotation of the first cooling fan 111 during printing in the same manner as the cooling fan 110A of the cooling mechanism 100A according to the first embodiment, thereby controlling the object to be cooled (here, the power supply unit 200). 4A and 4B, the temperature control indicated by the two-dot chain line L1 or L2 can be performed.

  On the other hand, the second cooling fan 112 is not connected to the fan rotation speed changing circuit 141, and always rotates at a constant speed. The second cooling fan 112 rotates at the same rotational speed as the first cooling fan 111 or at a lower rotational speed than the first cooling fan 111. Here, it is assumed that the second cooling fan 112 rotates at “low speed” when driven by a power supply voltage of DC12 (± 10%) (V).

  Hereinafter, a state where only the first cooling fan 111 is rotating is referred to as a “single fan drive state”. In addition, a state where both the first cooling fan 111 and the second cooling fan 112 are rotating is referred to as a “multiple fan driving state”. The “single fan drive state” is a “low efficiency cooling state”. The “multiple fan drive state” is a “highly efficient cooling state”.

  The control unit 120B includes an MPU 131, a fan rotation speed change circuit 141, an operational amplifier 142, a voltage dividing resistor 143, and an A / D converter 144, and includes an external interface 151, a storage unit 171, and a display operation unit. 2a, the image forming mechanism 60, and the sensor unit SN.

  The MPU 131 executes a control program stored in the storage unit 171 in advance, whereby a fan control unit 131a, a temperature decrease rate calculation unit 131b, a standby end temperature calculation unit 131c, a time calculation unit 131d, a temperature detection unit 131e, and It functions as the temperature comparison unit 131f. However, the MPU 131 also functions as a means for analyzing a print command and acquiring image data to be printed by executing a control program, and a means for driving the image forming mechanism 60. However, these means are publicly known. There is a low relevance to the characteristic part of the present invention, and the description is omitted here.

The fan control unit 131a is a functional unit that controls the rotation speed of the cooling fan 110, similarly to the fan control unit 121a of the first embodiment.
The temperature decrease rate calculation unit 131b is a functional unit that calculates the temperature decrease rate k3 in the single fan drive state F3 (see FIGS. 7A and 7B).

  The standby end temperature calculation unit 131c is a temperature at the end of standby in the single fan drive state F3 (hereinafter referred to as "standby end temperature in the single fan drive state F3") Td (see FIGS. 7A and 7B). ). Note that “the temperature Td at the end of standby in the single fan drive state F3” is “the temperature Td at the end of the low-efficiency cooling standby” when the cooling mechanism mounting device 1 is a device that realizes a function other than the printing process. "

  Similar to the time calculation unit 121d of the first embodiment, the time calculation unit 131d is a time (hereinafter referred to as “switching”) that reaches a switching threshold temperature (here, a third threshold temperature Tth3 (see FIGS. 7A and 7B) described later). It is a functional means for calculating t3).

  Similar to the temperature detection unit 121e of the first embodiment, the temperature detection unit 131e is a functional unit that detects the temperature of the object to be cooled (here, the power supply unit 200) as the detection temperature T.

  The temperature comparison unit 131f is a functional unit that determines whether or not the standby end temperature Td in the single fan drive state F3 is equal to or lower than a fourth threshold temperature Tth4.

  The storage unit 171 is a storage unit that stores various data necessary for controlling the cooling fans 111 and 112, a control program, and the like. Similarly to the storage unit 161 of the first embodiment, the storage unit 171 is preferably a plurality of storage areas, for example, a first storage unit 171a in which variable data is stored and a second storage unit 171b in which fixed data is stored in advance. It is good to be divided into. The first storage unit 171a and the second storage unit 171b may be configured by a single storage unit, or may be configured by a plurality of storage units.

  For example, data such as “switching threshold temperature” and “upper threshold temperature” is stored in the first storage unit 171a. In the second embodiment, the “switching threshold temperature” corresponds to “third threshold temperature Tth3 (see FIGS. 7A and 7B)”. The “upper threshold temperature” corresponds to “fourth threshold temperature Tth4 (see FIGS. 7A and 7B)”.

The “third threshold temperature Tth3” is a threshold temperature used to detect the timing of switching the state of the cooling fan 110 from the single fan drive state (low efficiency cooling state) to the multiple fan drive state (high efficiency cooling state). It is.
The “fourth threshold temperature Tth4” is detected at the end of the standby process when the state of the cooling fan 110 is switched from the single fan driving state (low efficiency cooling state) to the multiple fan driving state (high efficiency cooling state). This is the upper limit temperature (saturation temperature) of the thermistor 220. The cooling target (here, the power supply unit 200) is used when the temperature at the end of standby (hereinafter, referred to as “standby end temperature Tend2 (see FIGS. 7A and 7B))” is equal to or lower than the fourth threshold temperature Tth4. Suppose that there is no failure or alteration of characteristics.

  Further, in the second storage unit 171b, for example, “temperature drop rate k4 in the multiple fan drive state F4 (see FIG. 7B)”, “thermistor voltage-temperature conversion table D1 (not shown)”, “standby time” Data such as “twa (see FIGS. 7A and 7B)” is stored in advance. The “temperature decrease rate k4 in the multiple fan drive state F4” represents the temperature decrease rate in the multiple fan drive state F4 measured in advance.

  The voltage applied to the thermistor 220 of the power supply unit 200 is input to the MPU 131 of the control unit 120 </ b> B via the operational amplifier 142. Then, in the MPU 131, the temperature detection unit 131 e refers to the “thermistor voltage-temperature conversion table D 1 (not shown)” stored in the storage unit 171 in advance, and based on the input voltage value, the power supply unit 200. Is detected as a detection temperature T. In the MPU 131, the fan control unit 131 a controls the fan rotation speed changing circuit 141 based on the detected temperature T, and changes the driving state of the first and second cooling fans 111 and 112.

<Operation of cooling mechanism>
Hereinafter, the operation of the cooling mechanism will be described with reference to FIGS. 7A and 7B. 7A and 7B are diagrams each illustrating an operation of the cooling mechanism according to the second embodiment. FIGS. 7A and 7B are graphs showing changes in the temperature of the object to be cooled (here, the power supply unit 200) accompanying the control of the cooling states of the first cooling fan 111 and the second cooling fan 112, respectively.

  Here, a description will be given assuming that the color printer 1B has finished the printing process. Accordingly, here, the state of the color printer 1B changes in the order of “standby” and “power saving”.

  As shown in FIG. 7A, the cooling mechanism 100B starts driving only the first cooling fan 111 at a low speed when the color printer 1B finishes the printing process. That is, the cooling mechanism 100B enters the single fan drive state (low efficiency cooling state) F3. At this time, the detected temperature T starts to decrease from the temperature Tend at the end of printing at a temperature decrease rate k3 in the single fan drive state F3.

  When the detected temperature T reaches the third threshold temperature Tth3, the cooling mechanism 100B determines that the standby end temperature (low-efficiency cooling standby end temperature) Td in the predicted single fan drive state F3 is the fourth threshold temperature. It is determined whether or not Tth4 or less.

  When it is determined in this determination that the standby end temperature (low-efficiency cooling standby end temperature) Td in the predicted single fan drive state F3 is equal to or lower than the fourth threshold temperature Tth4 (“Td ≦ Tth4”). In addition, the cooling mechanism 100B performs temperature control indicated by a solid line L3 in FIG. 7A.

  That is, the cooling mechanism 100B drives only the first cooling fan 111 without switching the state of the first and second cooling fans 111 and 112 to the multiple fan drive state (high efficiency cooling state) F4 (see FIG. 7B). The single fan driving state (low-efficiency cooling state) F3 is maintained. As a result, the detected temperature T continues to decrease with the temperature decrease rate k3 in the single fan drive state F3.

  Then, the color printer 1B starts the power saving process when the standby time twa elapses after the standby process is started. At this time, the cooling mechanism 100B switches the state of the first and second cooling fans 111 and 112 from the single fan drive state (low efficiency cooling state) F3 to the fan stop state Fsp. As a result, the detected temperature T continues to decrease, but its decreasing rate decreases. In the second embodiment, when “Td ≦ Tth4”, the standby end temperature Tend2 is equal to the standby end temperature Td in the single fan drive state F3 (see FIG. 7A).

  On the other hand, the predicted single fan drive is determined by determining whether or not the standby end temperature (low efficiency cooling standby end temperature) Td in the predicted single fan drive state F3 is equal to or lower than the fourth threshold temperature Tth4. When it is determined that the standby end temperature (low-efficiency cooling standby end temperature) Td in the state F3 exceeds the fourth threshold temperature Tth4 ("Td> Tth4"), the cooling mechanism 100B is indicated by a one-dot chain line in FIG. 7B. The temperature control indicated by L4 is performed.

  That is, the cooling mechanism 100B changes the state of the first and second cooling fans 111 and 112 from the single fan driving state (low efficiency cooling state) F3 in which only the first cooling fan 111 is driven to the first and second. Switching to the multiple fan drive state (high efficiency cooling state) F4 in which the cooling fans 111 and 112 are both driven. As a result, the detected temperature T decreases at a temperature decrease rate k4 in the multiple fan drive state F4.

  Then, the color printer 1B starts the power saving process when the standby time twa elapses after the standby process is started. At this time, the cooling mechanism 100B switches the state of the first and second cooling fans 111 and 112 from the multiple fan drive state (high efficiency cooling state) F4 to the fan stop state Fsp. As a result, the detected temperature T continues to decrease, but its decreasing rate decreases. In the second embodiment, when “Td> Tth4”, the standby end temperature Tend2 is equal to the standby end temperature Te in the multiple fan drive state F4 (see FIG. 7B).

  The cooling mechanism 100B according to the second embodiment executes the process shown in FIG. 8 in order to realize the temperature control shown in FIGS. 7A and 7B. FIG. 8 is a flowchart showing the operation of the cooling mechanism according to the second embodiment.

  The cooling mechanism 100B stores data such as the temperature decrease rate k4 in the multiple fan drive state F4 in the storage unit 171 in advance. Here, “the temperature drop rate k4 in the multiple fan drive state F4” is, for example, a half of the minimum standby time twa in advance in a rated load state in a high-temperature and high-humidity environment and during standby processing of the apparatus. It is assumed that the temperature decreasing rate is measured when the color printer 1B performs the waiting process for the measurement time.

  When the printing process is completed, the color printer 1B shifts the state of the apparatus to the standby state and starts the standby process. In accordance with this, the cooling mechanism 100B starts the temperature control shown in FIGS. 7A and 7B along the flow shown in FIG.

  As shown in FIG. 8, at the start of standby (specifically, when the conveyance operation of the conveyance unit 50 is stopped), the cooling mechanism 100B is configured so that the fan control unit 131a sets the rotation speed of the first cooling fan 111 to a low speed. Then, the first cooling fan 111 is driven to start at a low speed (S605).

  At this time, the temperature detection unit 131e uses the voltage value detected by the thermistor 220 based on the “thermistor voltage-temperature conversion table D1 (not shown)” stored in advance in the storage unit 171 (the cooling target ( Here, the temperature of the power supply unit 200) is detected as the detected temperature T (S610). The detected temperature T at the first detection is the temperature Tend at the end of printing (see FIGS. 7A and 7B). The temperature Tend at the end of printing is also the temperature at the transition to the standby state. When the printing end temperature Tend is detected, the temperature detection unit 131e stores the printing end temperature Tend in the storage unit 171.

  After S610, the temperature detection unit 131e causes the detection temperature T to reach the third threshold temperature Tth3 until the detection temperature T reaches the third threshold temperature Tth3 (that is, until the detection temperature T decreases to the third threshold temperature Tth3). It is repeatedly determined whether or not it has been reached (S615). Here, the third threshold temperature Tth3 is, for example, 1/10 to 1/4 of the temperature decrease value when the first cooling fan 111 is driven at a low speed for 1 minute while the color printer 1B is on standby. The temperature is a value obtained by subtracting from the print end temperature Tend. When the temperature Tend at the end of printing is detected, the temperature detection unit 131e calculates the third threshold temperature Tth3 based on the temperature Tend at the end of printing, and stores the calculated third threshold temperature Tth3 in the storage unit 171. . The third threshold temperature Tth3 is calculated when the print end temperature Tend is detected without setting the third threshold temperature Tth3 to a fixed value because of the influence of the number of print jobs J or the temperature of the installation environment. This is because the temperature Tend at the end of printing is likely to fluctuate. That is, when the third threshold temperature Tth3 is set to a fixed value, the cooling mechanism 100B immediately changes the state of the first and second cooling fans 111 and 112 to the multiple fan drive state (high efficiency) when the print end temperature Tend is high. This is because it is necessary to switch to (cooling state) F4, and the period of the single fan driving state (low efficiency cooling state) F3 is shortened.

  When it is determined in S615 that the detected temperature T has reached the third threshold temperature Tth3 (in the case of “Yes”), the standby end temperature calculation unit 131c ends the standby in the single fan drive state F3. The hourly temperature Td is calculated (S620).

The calculation of “standby end temperature Td in the single fan driving state F3” is performed as follows.
First, when the detected temperature T reaches the third threshold temperature Tth3, the time calculation unit 131d takes a time (hereinafter referred to as “switching”) from the start of the standby process until the detected temperature T reaches the third threshold temperature Tth3. Is calculated and stored in the storage unit 171.

Then, the standby end temperature calculation unit 131c stores the “third threshold temperature Tth3”, “printing end temperature Tend”, “switching threshold arrival time t3”, and “standby time twa” stored in the storage unit 171. Referring to FIG. 8, the standby end temperature Td in the single fan drive state F3 is calculated based on the following equation (8), and the standby end temperature in the single fan drive state F3 is calculated. Td is stored in the storage unit 171.
Td = Tth3 + ((Tth3−Tend) ÷ t3) × (twa−t3) (8)

  After S620, the temperature comparison unit 131f determines whether or not the standby end temperature Td in the single fan drive state F3 is equal to or lower than the fourth threshold temperature Tth4 (“Td ≦ Tth4”) (S625).

The calculation of “fourth threshold temperature Tth4” is performed as follows.
When the switching threshold arrival time t3 is calculated, the temperature detection unit 131e stores “third threshold temperature Tth3”, “temperature decrease rate k4 in the multiple fan drive state F4”, and “standby” stored in the storage unit 171. Referring to “time twa” and “switching threshold arrival time t3”, “fourth threshold temperature Tth4” is calculated based on the following equation (9), and the calculated fourth threshold temperature Tth4 is calculated. The data is stored in the storage unit 171.
Tth4 = Tth3 + k4 × (twa−t3) (9)

  When it is determined in S625 that the standby end temperature Td in the single fan drive state F3 is equal to or lower than the fourth threshold temperature Tth4 (in the case of “Yes”), the cooling mechanism 100B performs the temperature shown in FIG. 7A. Take control. In this case, the cooling mechanism 100B allows the fan control unit 131a to switch the state of the first and second cooling fans 111 and 112 to the multiple fan drive state (high efficiency cooling state) F4 (see FIG. 7B). The single fan driving state (low efficiency cooling state) F3 in which only the first cooling fan 111 is driven is maintained.

  Then, the fan control unit 131a repeatedly determines whether or not the time has elapsed by the standby time twa until the time from the standby start time has elapsed by the “standby time twa” stored in the storage unit 171 ( S630).

  When it is determined in S630 that the time has elapsed by the waiting time twa (in the case of “Yes”), the fan control unit 131a sets the state of the first and second cooling fans 111 and 112 to a single state. The fan drive state (low efficiency cooling state) F3 is switched to the fan stop state Fsp (see FIG. 7A). That is, the fan control unit 131a stops driving the first cooling fan 111 (S635). Thereby, the cooling mechanism 100B ends the temperature control of the object to be cooled (here, the power supply unit 200) during the standby process. Accordingly, the color printer 1B finishes the standby process, and the state of the apparatus shifts to the power saving state.

  On the other hand, when it is determined in S625 that the standby end temperature Td in the single fan drive state F3 exceeds the fourth threshold temperature Tth4 (in the case of “No”), the cooling mechanism 100B is changed to FIG. Perform the temperature control shown. In this case, in the cooling mechanism 100B, the fan control unit 131a changes the state of the first and second cooling fans 111 and 112 from the single fan driving state (low efficiency cooling state) F3 to the multiple fan driving state (high efficiency cooling). State) Switch to F4 (see FIG. 7B). That is, the fan control unit 131a starts driving the second cooling fan 112 at a low speed (S640).

  Then, the fan control unit 131a repeatedly determines whether or not the time has elapsed by the standby time twa until the time from the standby start time has elapsed by the “standby time twa” stored in the storage unit 171 ( S645).

  When it is determined in S645 that the time has elapsed by the waiting time twa (in the case of “Yes”), the fan control unit 131a changes the state of the first and second cooling fans 111 and 112 to a plurality of fans. The driving state (high efficiency cooling state) F4 is switched to the fan stop state Fsp (see FIG. 7B). That is, the fan control unit 131a stops driving the first and second cooling fans 111 and 112 (S650). Thereby, the cooling mechanism 100B ends the temperature control of the object to be cooled (here, the power supply unit 200) during the standby process. Accordingly, the color printer 1B finishes the standby process, and the state of the apparatus shifts to the power saving state.

  The color printer 1B according to the second embodiment operates as follows by mounting the cooling mechanism 100B.

  That is, when the printing process is completed, the color printer 1B according to the second embodiment shifts the state of the apparatus to the standby state and starts the standby process. At this time, the color printer 1B is in a state where the temperature of each part has increased.

  Therefore, the cooling mechanism 100B drives the first cooling fan 111 to cool the object to be cooled until the time from the standby start time is equal to the “standby time twa” stored in the storage unit 171. At this time, the cooling mechanism 100B calculates “standby end temperature Td in the single fan drive state F3” as the temperature at the time of power saving transition, and calculates “fourth threshold temperature Tth4” as the upper limit threshold temperature. . Then, the cooling mechanism 100B drives the second cooling fan 112 as necessary based on the relationship between the “temperature at standby end Td in the single fan driving state F3” and the “fourth threshold temperature Tth4”. Increase cooling efficiency. Thereby, in the color printer 1B, the printing start temperature Tst (see FIGS. 4A and 4B) at the next printing is lower than when the second cooling fan 112 is not driven. Therefore, the color printer 1B can extend the period of the fan low-speed driving state (low efficiency cooling state) F1 as compared with the color printer 1A according to the first embodiment. As a result, the color printer 1B can reduce power consumption and noise during the next printing compared to the color printer 1A according to the first embodiment.

  Thereafter, the cooling mechanism 100 </ b> B stops driving the first cooling fan 111 when the time from the standby start time is equal to the “standby time twa” stored in the storage unit 171. Accordingly, the color printer 1B finishes the standby process, and the state of the apparatus shifts to the power saving state.

  As described above, according to the cooling mechanism 100B according to the second embodiment, similarly to the cooling mechanism 100A according to the first embodiment, the driving time of the cooling fan 110 in the high-efficiency cooling state (here, the multiple fan driving state F4). Thus, power consumption and noise can be suppressed.

Furthermore, according to the cooling mechanism 100B, the second cooling fan 112 can be driven as necessary to increase the cooling efficiency.
As a result, the job start temperature Tst (see FIGS. 4A and 4B) for the next job of the cooling mechanism mounting apparatus 1B can be made lower than when the second cooling fan 112 is not driven. As a result, according to the cooling mechanism 100B, the power consumption and noise during the next printing of the cooling mechanism mounting apparatus 1B can be reduced as compared with the color printer 1A according to the first embodiment.

  The present invention is not limited to the above-described embodiment, and various changes and modifications can be made without departing from the gist of the present invention.

  For example, the cooling mechanisms 100A and 100B may be configured to cool a heat roller of the fixing unit 40 or various switching elements (not shown) as objects to be cooled. In this case, the thermistor 220 is disposed on or around the object to be cooled.

  For example, in the first embodiment, the rotation speed of the cooling fan 110 is changed by changing the voltage applied to the cooling fan 110 with the operational amplifier 142. However, the rotation speed of the cooling fan 110 (DC fan) may be changed by changing the voltage applied to the cooling fan 110 with a Zener diode and a resistor (not shown). Such a circuit is realized, for example, by connecting a Zener diode and a resistor between a power supply terminal and a ground terminal, and connecting a DC fan between the Zener diode and the resistor.

  In addition, for example, the cooling unit 110 can be configured by a Peltier device (Peltier Device). The Peltier element is a plate-like semiconductor element that utilizes the Peltier effect that heat is transferred from one metal to the other when a current is passed through a joint between two kinds of metals. When a direct current is applied to the Peltier element, one surface absorbs heat and the other surface generates heat.

Further, for example, the present invention can be used not only in a printer but also in an image forming apparatus such as a facsimile machine, a copying machine, and an MFP. Note that “MFP” is an abbreviation for Multi Function Printer, and is an apparatus in which a facsimile function, a scanner function, a copy function, and the like are added to a printer.
Further, for example, the present invention is not limited to an image forming apparatus, and can be used for an apparatus configured to cool various cooling objects such as a projector.

1 (1A, 1B) Cooling mechanism mounting device (image forming device)
2 Main body portion 2a Display operation portion 2b Discharge stacker portion 3 Top cover portion 4 Print medium storage portion 5 Transport path 6 (6a) Roller (paper feed roller)
6 (6b) Roller (first registration roller)
6 (6c) Roller (second registration roller)
8 Conveying belt 10 Image forming unit 11 Developer storage unit 12 Photosensitive drum 20 Exposure unit (LED head)
DESCRIPTION OF SYMBOLS 30 Transfer part 31 Transfer roller 40 Fixing part 50 Conveying part 60 Image formation mechanism 100 (100A, 100B) Cooling mechanism 110 Cooling fan (cooling part)
111 Cooling fan (first cooling part)
112 Cooling fan (second cooling part)
120 (120A, 120B) Control unit 121, 131 MPU
121a, 131a Fan control unit 121b Temperature increase rate calculation unit 121c Print end temperature calculation unit 121d, 131d Time calculation unit 121e, 131e Temperature detection unit 121f Fan speed switching temperature calculation unit 131b Temperature decrease rate calculation unit 131c Standby end temperature calculation Unit 131f temperature comparison unit 141 fan rotation speed change circuit 142 operational amplifier 143 voltage dividing resistor 144 A / D converter 151 external interface 161, 171 storage unit 161a, 171a first storage unit 161b, 171b second storage unit 200 power supply unit ( Cooling object)
200a, 200b, 200c 1st, 2nd, 3rd output power supply 220 Thermistor D1 Thermistor voltage-temperature conversion table F1 Fan low-speed drive state (low efficiency cooling state)
F2 Fan high-speed driving state (high efficiency cooling state)
F3 Single fan drive state (low efficiency cooling state)
F4 Multiple fan drive state (high efficiency cooling state)
Fsp Fan stop state P Print medium SN Sensor part SN1 sensor (first transport sensor)
SN2 sensor (second transport sensor)
SN3 sensor (writing sensor)
SN4 sensor (discharge sensor)
Ta Fan low-speed printing end temperature (low-efficiency cooling job end temperature)
Tb Fan high-speed printing end temperature (high-efficiency cooling job end temperature)
Tc Switching temperature Td Temperature at end of standby in single fan drive state Te Temperature at end of standby in multiple fan drive state Tend Temperature at end of printing (job end temperature)
Tend2 Standby end temperature Tst Printing start temperature (Job start temperature)
Tth1 first threshold temperature (switching threshold temperature)
Tth2 second threshold temperature (upper threshold temperature)
Tth3 third threshold temperature (switching threshold temperature)
Tth4 Fourth threshold temperature (upper threshold temperature)
t1, t3 switching threshold arrival time t2 print end time (job end time)
twa standby time tx low speed allowable time

Claims (20)

In the cooling mechanism that cools the object to be cooled,
A cooling unit for cooling the cooling object;
A temperature detection unit for detecting the temperature of the cooling object as a detection temperature;
A control unit that switches the cooling state of the cooling unit to one of a low-efficiency cooling state with low cooling efficiency and a high-efficiency cooling state with higher cooling efficiency than the low-efficiency cooling state;
At least a switching threshold temperature used as a reference temperature for switching the cooling state of the cooling unit from the low-efficiency cooling state to the high-efficiency cooling state, and an upper-limit threshold temperature used as a temperature of an upper limit value of temperature control And a storage unit for storing
The control unit causes the cooling unit to be driven in the low-efficiency cooling state, and after that, even when the detected temperature reaches the switching threshold temperature, at the end of the processing in the low-efficiency cooling state When the temperature of the cooling unit becomes equal to or lower than the upper threshold temperature, the cooling mechanism is maintained in the low-efficiency cooling state without switching the cooling state of the cooling unit to the high-efficiency cooling state. The cooling mechanism according to claim 1,
The temperature at the start of job processing in which the cooling target is in a high heat generation state is defined as a job start temperature, the detected temperature is defined as a detected temperature, the switching threshold temperature is defined as a first threshold temperature, and the upper threshold temperature is defined as a first threshold temperature. When the threshold temperature is 2 and the predicted temperature at the end of job processing in the low efficiency cooling state is the temperature at the end of low efficiency cooling job,
The temperature detection unit detects the job start temperature as the detection temperature at the start of the job processing;
The controller is configured such that, even when the detected temperature rises from the job start temperature to the first threshold temperature during the job processing, the low efficiency cooling job end temperature is equal to or lower than the second threshold temperature. The cooling mechanism is characterized by maintaining the low-efficiency cooling state without switching the cooling state of the cooling unit to the high-efficiency cooling state. The cooling mechanism according to claim 2,
The controller is configured to detect the detected temperature when the detected temperature rises from the job start temperature to the first threshold temperature and when the low efficiency cooling job end temperature exceeds the second threshold temperature. When the temperature reaches a predetermined switching temperature, the cooling mechanism switches the state of the cooling section from the low efficiency cooling state to the high efficiency cooling state. The cooling mechanism according to claim 2 or claim 3,
The detected temperature is “T”, the job start temperature is “Tst”, the first threshold temperature is “Tth1”, the low efficiency cooling job end temperature is “Ta”, and the detected temperature T is When the time required to increase from the job start temperature Tst to the first threshold temperature Tth1 is the switching threshold arrival time t1, and the time required from the start to the end of the job processing is the job end time t2,
The low-efficiency cooling job end temperature Ta is calculated by the formula (1) based on the first threshold temperature Tth1, the job start temperature Tst, the switching threshold arrival time t1, and the job end time t2. Ta = Tth1 + ((Tth1−Tst) ÷ t1) × (t2−t1) (1)
A cooling mechanism characterized by that. The cooling mechanism according to claim 3,
The detected temperature is “T”, the job start temperature is “Tst”, the first threshold temperature is “Tth1”, the second threshold temperature is “Tth2”, and the predetermined switching temperature is “Tc”. The temperature increase rate per fixed time in the low efficiency cooling state is a low efficiency cooling temperature increase rate k1, and the temperature increase rate per fixed time in the high efficiency cooling state is a high efficiency cooling temperature increase rate k2. The time required for the detected temperature T to rise from the job start temperature Tst to the first threshold temperature Tth1 is defined as a switching threshold arrival time t1, and the time required from the start to the end of the job processing is the job end time. If t2
The switching temperature Tc includes the first threshold temperature Tth1, the second threshold temperature Tth2, the low efficiency cooling temperature increase rate k1, the high efficiency cooling temperature increase rate k2, the switching threshold arrival time t1, and the job. Based on the end time t2, Tc = (k1 * Tth2-k1 * k2 * (t2-t1) -k2 * Tth1) / (k1-k2) (2)
A cooling mechanism characterized by that. The cooling mechanism according to claim 5, wherein
The low-efficiency cooling temperature rise rate k1 is calculated by the equation (3). K1 = (Tth1−Tst) ÷ t1 (3)
A cooling mechanism characterized by that. The cooling mechanism according to claim 5 or 6,
The high-efficiency cooling temperature increase rate k2 is stored in advance in the storage unit. The cooling mechanism according to claim 7,
The storage section stores a first storage section that stores the first threshold temperature Tth1 as the switching threshold temperature and the second threshold temperature Tth2 as the upper limit threshold temperature, and the high-efficiency cooling temperature increase rate k2. And a second storage unit that is partitioned. The cooling mechanism according to any one of claims 3 to 8,
The predicted temperature at the end of job processing when the cooling state of the cooling unit is switched to the high efficiency cooling state is the temperature at the end of the high efficiency cooling job,
The controller is
The cooling state of the cooling unit when the difference between the temperature at the end of the low-efficiency cooling job and the temperature at the end of the high-efficiency cooling job is greater than the difference between the second threshold temperature and the temperature at the end of the low-efficiency cooling job Switching from the low efficiency cooling state to the high efficiency cooling state,
On the other hand, when the difference between the temperature at the end of the low efficiency cooling job and the temperature at the end of the high efficiency cooling job is equal to or less than the difference between the second threshold temperature and the temperature at the end of the low efficiency cooling job, the cooling unit A cooling mechanism that maintains the low-efficiency cooling state without switching the cooling state to the high-efficiency cooling state. The cooling mechanism according to any one of claims 1 to 9,
The temperature at the start of standby processing after the job processing in which the cooling target is in a high heat generation state is finished as the temperature at the end of the job, the detected temperature as the detected temperature, and the switching threshold temperature as the third threshold temperature. And when the upper limit threshold temperature is the fourth threshold temperature and the predicted temperature at the end of the standby process in the low-efficiency cooling state is the low-efficiency cooling standby end temperature,
The temperature detection unit detects the job end temperature as the detection temperature at the start of the standby process,
The control unit is configured such that, even when the detected temperature falls from the job end temperature to the third threshold temperature during the standby process, the low efficiency cooling standby end temperature is equal to or lower than the fourth threshold temperature. The cooling mechanism is characterized by maintaining the low-efficiency cooling state without switching the cooling state of the cooling unit to the high-efficiency cooling state. The cooling mechanism according to claim 10, wherein
The detected temperature is “T”, the job end temperature is “Tend”, the third threshold temperature is “Tth3”, the low efficiency cooling standby end temperature is “Td”, and the detected temperature T is When the time required for the temperature to fall from the job end temperature Tend to the third threshold temperature Tth3 is defined as a switching threshold arrival time t3, and the time from the start to the end of the standby processing is defined as a standby time twa.
The low-efficiency cooling standby end temperature Td is calculated by the equation (4) based on the third threshold temperature Tth3, the job end temperature Tend, the switching threshold arrival time t3, and the standby time twa. Td = Tth3 + ((Tth3−Tend) ÷ t3) × (twa−t3) (4)
A cooling mechanism characterized by that. The cooling mechanism according to any one of claims 1 to 11,
The cooling mechanism, wherein the object to be cooled is a power supply unit. The cooling mechanism according to any one of claims 1 to 12,
The cooling mechanism, wherein the cooling unit is configured as a cooling fan. The cooling mechanism according to claim 13,
The control unit switches the cooling state of the cooling unit between the low-efficiency cooling state and the high-efficiency cooling state by changing the rotation speed of the cooling fan. . The cooling mechanism according to claim 14, wherein
The cooling mechanism is characterized in that the rotation speed of the cooling fan is changed by changing a voltage applied to the cooling fan with a Zener diode. The cooling mechanism according to claim 13,
A plurality of the cooling fans are provided,
The control unit switches the cooling state of the cooling unit to one of the low efficiency cooling state and the high efficiency cooling state by changing the number of the cooling fans to be rotated. mechanism. The cooling mechanism according to any one of claims 1 to 12,
The cooling mechanism, wherein the cooling unit is configured as a Peltier element. In the cooling mechanism mounting device that mounts the cooling mechanism that cools the object to be cooled,
A cooling mechanism mounting apparatus, wherein the cooling mechanism according to any one of claims 1 to 17 is mounted. The cooling mechanism mounting device according to claim 18,
The apparatus is configured as an image forming apparatus that forms an image by an electrophotographic process,
A cooling mechanism mounting apparatus, wherein a power supply unit that supplies power to each unit is the cooling object, and the cooling mechanism is used for cooling the power supply unit. The cooling mechanism mounting device according to claim 18,
The device is configured as a projector,
A cooling mechanism mounting apparatus, wherein a power supply unit that supplies power to each unit is the cooling object, and the cooling mechanism is used for cooling the power supply unit.

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