Image forming apparatus, temperature adjustment method, and temperature adjustment program

Abstract

To prevent the generation of noise.SOLUTION: An image forming apparatus comprises: a CPU 111 that executes a program; a cooling unit 115 that cools the processor; and a temperature sensor 116 that detects the temperature of the CPU 111. The CPU 111 determines a reference temperature on the basis of the rate of increase of temperature detected by the temperature sensor 116 in an activation period, and actuates the cooling unit 115 on the basis of the reference temperature and temperature detected by the temperature sensor 116 in an actual operating period different from the activation period.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an image forming apparatus, a temperature adjustment method, and a temperature adjustment program, and more particularly to a temperature adjustment method for adjusting the temperature of a control unit that controls the image forming apparatus and a temperature adjustment program for causing a computer to execute the temperature adjustment method.

Background Art

[0002] In recent years, image forming apparatuses represented by multifunction peripherals (MFPs) have been known. This image forming apparatus is controlled by a central processing unit (CPU). In addition to processing for executing functions for forming images, the CPU executes data processing such as virus checking or data backup. Since the temperature of the CPU rises when a processing load is applied, it is common for the CPU to be cooled using a cooling fan.

[0003] Japanese Patent Application Laid-Open No. 2007-150605 discloses an image forming apparatus that cools a processor that performs various processes such as image processing according to a detection output of a temperature sensor that detects the temperature of the processor by a cooling unit, and calculates a temperature rise rate of the processor based on the temperature detected by the temperature sensor. A temperature rise rate calculation means, a first determination means for determining whether or not the calculated temperature rise rate is equal to or greater than a predetermined value set in advance, and a large temperature rise in the processor when it is determined by the first determination means that the temperature rise rate is equal to or greater than the predetermined value. A second determination means for determining whether or not the process related to the job causing the above is being executed, and a cooling operation control means for operating the cooling means when it is determined that the processor is executing the job causing the large temperature rise are provided. An image forming apparatus is described.

[0004] However, there are individual differences in the rate of temperature rise among processors. Therefore, when the cooling means is operated using a predetermined threshold value, the processor with a relatively small rate of temperature rise may be cooled unnecessarily. In particular, since MFPs are often placed in workplaces and the like, it is desirable to minimize the noise generated by the cooling operation.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] This invention has been made to solve the above-described problems, and one of the objects of this invention is to provide an image forming apparatus that suppresses the generation of noise.

[0007] Another object of this invention is to provide a temperature adjustment method that suppresses the generation of noise.

[0008] Still another object of this invention is to provide a temperature adjustment program that suppresses the generation of noise.

Means for Solving the Problems

[0009] According to an aspect of this invention, an image forming apparatus includes a processor that executes a program, a cooling means that cools the processor, and a detection means that detects the temperature of the processor. The processor determines a reference temperature based on the rate of temperature rise detected by the detection means during a startup period, and operates the cooling means based on the temperature detected by the detection means and the reference temperature during an actual operation period different from the startup period.

[0010] According to another aspect of the present invention, a temperature adjustment method is a temperature adjustment method executed by a processor that controls an image forming apparatus. The image forming apparatus includes a cooling unit that cools the processor and a detection unit that detects the temperature of the processor. The method includes a determination step of determining a reference temperature based on a rate of increase in temperature detected by the detection unit during a startup period, and a startup step of operating the cooling unit based on the temperature detected by the detection unit and the reference temperature during an operation period different from the startup period, and causing the processor to execute these steps.

[0011] According to still another aspect of the present invention, a temperature adjustment program is a temperature adjustment program executed by a processor that controls an image forming apparatus. The image forming apparatus includes a cooling unit that cools the processor and a detection unit that detects the temperature of the processor. The program includes a determination step of determining a reference temperature based on a rate of increase in temperature detected by the detection unit during a startup period, and a startup step of operating the cooling unit based on the temperature detected by the detection unit and the reference temperature during an operation period different from the startup period, and causing the processor to execute these steps.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[0013] Hereinafter, the multifunction device according to the embodiment of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions thereof will not be repeated.

[0014] FIG. 1 is a perspective view showing the appearance of the MFP in the present embodiment. Referring to FIG. 1, the MFP (Multi Function Peripheral) 1 is an example of an image forming apparatus and has a function of forming an image on a recording medium such as paper.

[0015] The MFP 1 includes an automatic document feeder 2, a document reading unit 3, an image forming unit 4, a paper feeding unit 5, and an operation panel 6. The automatic document feeder 2 automatically conveys a plurality of documents set on the document tray one by one to the document reading position of the document reading unit 3, and discharges the document on which the image formed on the document has been read by the document reading unit 3 to the document discharge tray.

[0016] The document reading unit 3 includes a light source that irradiates light and a photoelectric conversion element that receives light, and scans the image formed on the document placed on the reading surface. When a document is placed in the reading area, the light irradiated from the light source is reflected by the document, and the reflected light forms an image on the photoelectric conversion element. When the photoelectric conversion element receives the light reflected by the document, it generates image data obtained by converting the received light into an electrical signal.

[0017] The paper feed unit 5 includes two paper feed cassettes 35, 35A for accommodating sheets. The paper feed unit 5 conveys the sheets accommodated in either of the two paper feed cassettes 35, 35A to the image forming unit 4. The image forming unit 4 forms an image by a well-known electrophotographic method. Based on image data, it forms an image on the sheet conveyed by the paper feed unit 5 and discharges the sheet on which the image has been formed to the paper discharge tray 7.

[0018] The operation panel 6 has a display unit 161 and an operation unit 163, and receives operations input by the user.

[0019] FIG. 2 is a cross-sectional view schematically showing an example of the internal configuration of the MFP. FIG. 2 shows a cross-section of the MFP1 as viewed from the front. Referring to FIG. 2, the document reading unit 3 exposes the image of the document set on the document glass 11 by the automatic document feeder 2 with an exposure lamp 13 attached to a slider 12 that moves in the sub-scanning direction indicated by the arrow in the figure below it. The exposure lamp 13 is in a shape extending in the main scanning direction perpendicular to the sub-scanning direction. The reflected light from the document is guided to the lens 16 by the mirror 14 and two reflecting mirrors 15, 15A, and forms an image on the CCD (Charge Coupled Devices) sensor 18.

[0020] In the CCD sensor 18, a plurality of photoelectric conversion elements are arranged in the main scanning direction. The reflected light that forms an image on the CCD sensor 18 is converted into image data as an electrical signal within the CCD sensor 18. The image data is converted into printing data for cyan (C), magenta (M), yellow (Y), and black (K), and output to the image forming unit 4.

[0021] A housing 9 is arranged below the document reading unit 3. Inside the housing 9, the image forming unit 4, the paper feed unit 5, and the board storage box 100 are stored. Details of the board storage box 100 will be described later, but one or more boards are stored. The one or more boards include a board on which a CPU 111 (see FIG. 3) that controls the entire MFP1 is mounted.

[0022] The image forming unit 4 includes image forming units 20Y, 20M, 20C, and 20K corresponding to yellow, magenta, cyan, and black respectively. Here, "Y", "M", "C", and "K" represent yellow, magenta, cyan, and black respectively. When at least one of the image forming units 20Y, 20M, 20C, 20K is driven, an image is formed. When all of the image forming units 20Y, 20M, 20C, 20K are driven, a full-color image is formed. Printing data for yellow, magenta, cyan, and black is input into the image forming units 20Y, 20M, 20C, 20K respectively. Since the image forming units 20Y, 20M, 20C, 20K only differ in the color of the toner they handle, here, the image forming unit 20Y for forming a yellow image will be described.

[0023] The image forming unit 20Y includes a charging roller 21Y, an exposure device 22Y, a developing device 23Y, a primary transfer roller 24Y, a photosensitive drum 25Y which is an image carrier, and a toner bottle 41Y. The toner bottle 41Y stores yellow toner. The toner bottle 41Y rotates with a toner bottle motor as a drive source and discharges the developer to the outside. The toner discharged from the toner bottle 41Y is supplied to the developing device 23Y.

[0024] The photosensitive drum 25Y has a cylindrical shape, and around the photosensitive drum 25Y, the charging roller 21Y, the exposure device 22Y, the developing device 23Y, and the primary transfer roller 24Y are arranged in order along the rotation direction of the photosensitive drum 25Y.

[0025] After the surface of the photosensitive drum 25Y is charged by the charging roller 21Y, it is irradiated with the laser light emitted by the exposure device 22Y. The exposure device 22Y exposes the image corresponding portion on the surface of the photosensitive drum 25Y to form an electrostatic latent image. Thereby, an electrostatic latent image is formed on the photosensitive drum 25Y. Subsequently, the developing device 23Y develops the electrostatic latent image formed on the photosensitive drum 25Y with toner. Specifically, toner held by the developing roller of the developing device 23Y is placed on the electrostatic latent image formed on the photosensitive drum 25Y by the action of the electric field force, whereby a toner image is formed on the photosensitive drum 25Y. The toner image formed on the photosensitive drum 25Y is transferred onto the transfer belt 30, which is an image carrier, by the action of the electric field force by the primary transfer roller 24Y.

[0026] The transfer belt 30 is suspended by the driving roller 33 and the driven roller 29 so as not to be slack. When the driving roller 33 rotates clockwise in FIG. 2, the transfer belt 30 rotates clockwise in the figure at a predetermined speed. Along with the rotation of the transfer belt 30, the driven roller 29 rotates clockwise. Thereby, the image forming units 20Y, 20M, 20C, 20K transfer toner images onto the transfer belt 30 in this order. The timing for each of the image forming units 20Y, 20M, 20C, 20K to transfer a toner image onto the transfer belt 30 is adjusted by detecting a reference mark attached to the transfer belt 30. Thereby, yellow, magenta, cyan, and black toner images are superimposed on the transfer belt 30.

[0027] When the MFP1 forms a full-color image, it drives all of the image forming units 20Y, 20M, 20C, 20K. Thereby, yellow, magenta, cyan, and black toner images are superimposed on the transfer belt 30. When the MFP1 forms a monochrome image, it drives any one of the image forming units 20Y, 20M, 20C, 20K. Also, an image can be formed by combining two or more of the image forming units 20Y, 20M, 20C, 20K.

[0028] The paper feed cassettes 35 and 35A are each set with papers of different sizes. The papers housed in the paper feed cassettes 35 and 35A are each supplied to the conveyance path by the take-out rollers 36 and 36A respectively attached to the paper feed cassettes 35 and 35A, and are sent to the timing roller 31 by the paper feed roller 37.

[0029] The timing roller 31 conveys the paper conveyed by the paper feed roller 37 to the nip portion between the transfer belt 30 and the secondary transfer roller 26 which is a transfer member. The secondary transfer roller 26 generates an electric field in the nip portion. By the action of the electric field force in this nip portion, the toner image formed on the transfer belt 30 is transferred to the paper conveyed by the timing roller 31. The paper onto which the toner image has been transferred is conveyed to the fixing roller pair 32 and is heated and pressed by the fixing roller pair 32. Thereby, the toner is melted and fixed to the paper. Thereafter, the paper is discharged to the paper discharge tray 7.

[0030] Here, an example in which the MFP 1 adopts a tandem method including the image forming units 20Y, 20M, 20C, and 20K that form each of the four-color toners on the paper will be described. However, a four-cycle method in which the four-color toners are sequentially transferred onto the paper by one photosensitive drum may be adopted for the MFP 1.

[0031] FIG. 3 is a block diagram showing an example of a detailed configuration of the substrate storage box. Referring to FIG. 3, the substrate storage box 100 includes a main control unit 110 and a plurality of other control units. The plurality of other control units include a document conveyance control unit 121, a document reading control unit 122, an image forming control unit 123, a paper conveyance control unit 124, a FAX control unit 125, a communication control unit 126, a panel control unit 127, and a memory control unit 128. In the present embodiment, each of the main control unit 110 and the plurality of other control units is a printed wiring board on which a plurality of electronic components are mounted.

[0032] The main control unit 110 is equipped with a central processing unit (CPU) 111, a ROM (Read Only Memory) 112 that stores programs to be executed by the CPU 111, a RAM (Random Access Memory) 113 used as the working area of the CPU 111, an HDD (Hard Disk Drive) 114, a cooling unit 115, and a temperature sensor 116.

[0033] The ROM 112 stores programs executed by the CPU 111 or data necessary for executing those programs. The RAM 113 is used as the working area when the CPU 111 executes programs. The HDD 114 is controlled by the CPU 111 and stores data non-volatily.

[0034] The cooling unit 115 is arranged near the CPU 111. The cooling unit 115 includes a motor and a fan attached to the rotating shaft of the motor. The cooling unit 115 is controlled by the CPU 111 to rotate the motor. As a result, the fan rotates, and the air generated by the rotating fan is sent toward the CPU 111. When the cooling unit 115 operates, the air around the CPU 111 convects. Thereby, when the heat generated by the CPU 111 is taken away by the air, the CPU 111 is cooled.

[0035] The temperature sensor 116 is controlled by the CPU 111. The temperature sensor 116 is arranged at a position in contact with the CPU 111. The position where the temperature sensor 116 is arranged is not limited to the position in contact with the CPU 111 and may be arranged near the CPU 111. In this case, since the cooling unit 115 blows air onto the CPU 111, it is preferably arranged at a position that does not directly receive the air. For example, it is preferably arranged on the side opposite to the cooling unit 115 with the CPU 111 in between. The temperature sensor 116 detects the temperature of the CPU 111 and outputs the detected temperature to the CPU 111.

[0036] The CPU 111 is connected to a document conveyance control unit 121, a document reading control unit 122, an image forming control unit 123, a paper conveyance control unit 124, a FAX control unit 125, a communication control unit 126, a panel control unit 127, and a memory control unit 128, and controls the entire MFP 1.

[0037] The document conveyance control unit 121 controls the automatic document feeder 2. The CPU 111 causes the automatic document feeder 2 to read a document via the document conveyance control unit 121. The document reading control unit 122 controls the document reading unit 3. The CPU 111 causes the document reading unit 3 to read a document via the document reading control unit 122. The image forming control unit 123 controls the image forming unit 4. The CPU 111 causes the image forming unit 4 to form an image on a sheet via the image forming control unit 123. The paper conveyance control unit 124 controls the paper feeding unit 5. The CPU 111 causes the paper feeding unit 5 to convey a sheet to the image forming unit 4 via the paper conveyance control unit 124.

[0038] The FAX control unit 125 is connected to the public switched telephone network (PSTN). The FAX control unit 125 transmits and receives facsimile data via the PSTN. The CPU 111 transmits data by facsimile via the FAX control unit 125. Also, the CPU 111 acquires facsimile data received from the outside by the FAX control unit 125 from the FAX control unit 125.

[0039] The communication control unit 126 is an interface for connecting the MFP 1 to a network. The CPU 111 communicates with other computers connected to the network via the communication control unit 126 and transmits and receives data.

[0040] The panel control unit 127 controls the operation panel 6. The operation panel 6 is provided on the upper surface of the MFP 1 and includes a display unit 131 and an operation unit 132. The display unit 131 is a display device such as a liquid crystal display (LCD) or an organic ELD (Electro-Luminescence Display), and displays instruction menus for the user, information on acquired image data, and the like. The operation unit 132 includes hard keys composed of a plurality of keys, and accepts various instructions, input of data such as characters and numbers, by operations of the user corresponding to the keys. The operation unit 132 further includes a touch panel provided on the display unit 131.

[0041] The CPU 111 notifies the user of the information contained in the image by displaying the image on the display unit 131 via the panel control unit 127. Further, the CPU 111 accepts the operations input by the user via the operation unit 132 via the panel control unit 127.

[0042] The memory control unit 128 controls the external storage device 129. The external storage device 129 has a CD-ROM (Compact Disk ROM) 117 mounted thereon. The memory control unit 128 accesses the CD-ROM 117 via the external storage device 129. The CPU 111 acquires the data recorded on the CD-ROM 117 mounted on the external storage device 129 via the memory control unit 128.

[0043] In this embodiment, a case where the main control unit 110 and a plurality of other control units are stored in the substrate storage box 100 will be described as an example. However, it is sufficient that at least the main control unit 110 is stored in the substrate storage box 100. The plurality of other control units are selectively stored. In order to meet the requirements of a large number of users, a plurality of control units are selected and stored in the substrate storage box 100. For example, when the user does not need the facsimile transmission / reception function, the FAX control unit 125 is not stored in the substrate storage box 100. When the user does not need the automatic document feeder 2, the document conveyance control unit 121 is not stored in the substrate storage box 100. When the user does not need the document reading unit 3, the document conveyance control unit 121 and the document reading control unit 122 are not stored in the substrate storage box 100. When the user does not need the external storage device 129, the storage control unit 128 is not stored in the substrate storage box 100.

[0044] The CPU 111 loads and executes the program stored in the CD-ROM 117 or the HDD 114 into the RAM 113. The program stored in the HDD 114 includes the program downloaded by the MFP 1 from another computer connected to the network and stored in the HDD 114. The program stored in the HDD 114 includes the program added and written to the HDD 114 by another computer connected to the network. Also, the program stored in the HDD 114 includes the program obtained by rewriting the program stored in the HDD 114 by another computer connected to the network. The program referred to here includes not only the program directly executable by the CPU 111 but also the source program, the compressed program, the encrypted program, etc.

[0045] The medium for storing the program executed by the CPU 111 is not limited to the HDD 114 and the CD-ROM 117, and may be an optical disk such as MO (Magnetic Optical Disc) / MD (Mini Disc) / DVD (Digital Versatile Disc), an IC card, an optical card, a mask ROM, a semiconductor memory such as an EPROM (Erasable Programmable ROM), etc.

[0046] FIG. 4 is a block diagram showing an example of the functions of the CPU included in the MFP in the present embodiment. The functions shown in FIG. 4 are functions realized in the CPU 111 by the CPU 111 included in the MFP 1 executing a temperature adjustment program stored in the ROM 112, the HDD 114, or the CD-ROM 117. Referring to FIG. 4, the CPU 111 included in the MFP 1 includes a CPU temperature detection unit 51, a reference temperature determination unit 53, a cooling control unit 55, an operation reception unit 57, and an image formation control unit 59. When the power is turned on for the MFP 1, the power is turned on for the CPU 111. The CPU 111 executes a boot program or the like in response to the power being turned on, and a control program for controlling the temperature adjustment program and each of the other plurality of control units is executed. The period from when the power is turned on for the CPU 111 until the control program for controlling the temperature adjustment program and each of the other plurality of control units is executed and the image formation becomes possible is referred to as the startup period. Note that the startup period may be a predetermined period after the CPU 111 is started up.

[0047] During the startup period, the rate of temperature rise of CPU 111 may vary depending on the solid difference or the difference in the functions of MFP 1. The difference in the functions of MFP 1 is the number of substrates stored in substrate storage box 100. As described above, substrate storage box 100 may not store at least one of a plurality of other control units. If the number of substrates stored in substrate storage box 100 is different, the functions of MFP 1 are different. When MFP 1 has more functions, compared with the case of having fewer functions, more processes are executed during the startup period, and the load on CPU 111 increases. The greater the load on CPU 111 during the startup period, the greater the rate of temperature rise.

[0048] CPU temperature detection unit 51 controls temperature sensor 116 to detect the temperature of CPU 111 by temperature sensor 116. CPU temperature detection unit 51 acquires the temperature output by temperature sensor 116 and outputs the acquired temperature to reference temperature determination unit 53 and cooling control unit 55 as the temperature of CPU 111.

[0049] Reference temperature determination unit 53 determines a reference temperature. The reference temperature is a threshold value used by cooling control unit 55 to determine the activation of cooling unit 115. Reference temperature determination unit 53 receives the temperature of CPU 111 from CPU temperature detection unit 51.

[0050] The reference temperature determination unit 53 includes a rate of rise determination unit 61. The rate of rise determination unit 61 determines the rate of rise of the temperature of the CPU 111 during the startup period. The rate of rise determination unit 61 determines the rate of rise from the temperature at the time when power is supplied to the CPU 111 and the temperature at the time when the temperature adjustment program and control programs for controlling the plurality of other control units are executed and the image forming enabled state is reached. Note that the rate of rise may be determined from the time measured from when the temperature is input from the CPU temperature detection unit 51 until the rising temperature reaches a predetermined value and the measured time and the predetermined value. The startup period in this case is the period from when power is supplied to the CPU 111 until the temperature of the CPU 111 that rises reaches a predetermined value. Further, the startup period may be a predetermined period from when power is supplied to the CPU 111. In this case, the rate of rise determination unit 61 determines the rate of rise from the difference between the temperature first detected after power is supplied to the CPU 111 and the temperature detected after the predetermined period has elapsed and the predetermined period.

[0051] The reference temperature determination unit 53 determines a reference temperature based on the rate of rise determined by the rate of rise determination unit 61. The reference temperature includes a start threshold value S for starting the operation of the cooling unit 115 and a stop threshold value P for stopping the operation of the cooling unit 115. A correlation table associating the rate of rise and the start threshold value S is stored in advance in the HDD 114, and the reference temperature determination unit 53 refers to the correlation table to determine the start threshold value S. Further, a function for determining the start threshold value S from the air supply capacity of the cooling unit 115 and the rate of rise may be prepared in advance, and the start threshold value S may be determined using the function. The stop threshold value P is determined to be a value smaller than the start threshold value S.

[0052] The operation reception unit 57 controls the operation panel 6 and receives operations input by the user to the operation unit 132. While the operation unit 132 is receiving the operations input by the user, the operation reception unit 57 outputs an operation-in-progress signal indicating that the user is operating the MFP 1 to the cooling control unit 55.

[0053] The image formation control unit 59 controls the image forming unit 4 and the paper feeding unit 5, and executes an image formation process for forming an image on the paper supplied from the paper feeding unit 5 to the image forming unit 4. While the image formation control unit 59 controls the image forming unit 4 and the paper feeding unit 5 to execute the image formation process, it outputs an operating signal to the cooling control unit 55.

[0054] The cooling control unit 55 controls the cooling unit 115 and operates the cooling unit 115. The cooling control unit 55 includes an actual operation period determination unit 65. The actual operation period determination unit 65 determines the actual operation period. The actual operation period determination unit 65 sets, as the actual operation period, the period excluding the startup period among the periods during which the CPU 111 is operating. The actual operation period determination unit 65 receives an operation signal indicating that the user is operating from the operation reception unit 57 and an operating signal indicating that image formation is in progress from the image formation control unit 59. The actual operation period determination unit 65 excludes the period during which an operation signal is input from the operation reception unit 57 from the actual operation period. Also, the actual operation period determination unit 65 excludes the period during which an operating signal is input from the image formation control unit 59 from the actual operation period. Therefore, the actual operation period is the period after the startup period, during which the user is not operating the operation panel 6 and the automatic document feeder 2, document reading unit 3, image forming unit 4, and paper feeding unit 5 are not operating.

[0055] The period during which an operation signal is input from the operation reception unit 57 is the period during which the user is operating the MFP 1, and it is highly likely that a document reading process and an image formation process will be executed thereafter. While the document reading process is being executed, the CPU 111 executes a process of controlling the document conveyance control unit 121 and the document reading control unit 122, so the temperature of the CPU 111 rises. Also, during the period in which an operating signal is input from the image formation control unit 59, the CPU 111 executes a process of controlling the image formation control unit 123 and the paper conveyance control unit 124, so the temperature of the CPU 111 rises. For this reason, the cooling control unit 55 drives the cooling unit 115 regardless of the temperature of the CPU 111 during the period in which an operation signal is input from the operation reception unit 57 and during the period in which an operating signal is input from the image formation control unit 59.

[0056] During the operation period, the CPU 111 may execute facsimile transmission / reception processing, data transmission / reception processing, data processing, etc. When the CPU 111 executes facsimile transmission / reception processing, it controls the FAX control unit 125 to transmit and receive facsimile data. Also, when the CPU 111 executes data transmission / reception processing, it controls the communication control unit 126 to transmit and receive data. Further, the data processing executed by the CPU 111 performs virus check processing on the data stored in the HDD 114 or performs processing to back up the data. While the CPU 111 is executing processing during the operation period, the automatic document feeder 2, document reading unit 3, image forming unit 4, and paper feeding unit 5 do not operate. Therefore, no mechanical noise is generated.

[0057] The cooling control unit 55 receives the temperature of the CPU 111 from the CPU temperature detection unit 51. The cooling control unit 55 controls the cooling unit 115 based on the temperature of the CPU 111 during the operation period. The cooling control unit 55 drives the cooling unit 115 in response to the temperature of the CPU 111 becoming equal to or higher than the start threshold value S of the reference temperature. Thereby, the wind generated from the cooling unit 115 is sent to the CPU 111, and the cooling of the CPU 111 starts. The cooling control unit 55 stops the cooling unit 115 in response to the temperature of the CPU 111 becoming equal to or lower than the stop threshold value P of the reference temperature. Thereby, since no wind is sent from the cooling unit 115 to the CPU 111, the cooling of the CPU 111 stops. After that, when the CPU 111 executes processing, the temperature rises.

[0058] FIG. 5 is a diagram showing an example of temperature changes during the operation period of two CPUs with different temperature rise rates during the startup period. In FIG. 5, the temperature change of the CPU with a high rise rate is shown by a thin line, and the temperature change of the CPU with a low rise rate is shown by a thick line.

[0059] Referring to FIG. 5, taking the case where the start threshold value S1 and the stop threshold value P1 are determined for a CPU with a high rising rate as an example, the start threshold value S1 is larger than the stop threshold value P1. For a CPU with a high rising rate, the temperature rises while the cooling unit 115 is not operating, and at time t1, the temperature reaches the start threshold value S1. Thereafter, the cooling unit 115 starts operating to cool the CPU 111, but the temperature of the CPU 111 continues to rise until time t3. During this period, the amount of heat generated by the CPU 111 is larger than the cooling capacity of the cooling unit 115. After time t3, since the difference between the temperature of the CPU 111 and the temperature of the air blown by the cooling unit 115 becomes large, the cooling capacity of the cooling unit 115 exceeds the amount of heat generated by the CPU 111. Therefore, after time t3, the temperature of the CPU 111 begins to decrease. Thereafter, when the temperature of the CPU 111 becomes equal to or lower than the stop threshold value P1, the cooling unit 115 is stopped. Let the period from time t1 when the temperature of the CPU with a high rising rate reaches the start threshold value S1 to time t3 when the temperature begins to decrease be T1.

[0060] Explaining the case of operating the cooling unit 115 by applying the start threshold value S1 and the stop threshold value P1 determined for a CPU with a high rising rate to a CPU with a low rising rate. In this case, for the CPU with a low rising rate, the temperature rises while the cooling unit 115 is not operating, and at time t2, the temperature reaches the start threshold value S1. Thereafter, the cooling unit 115 starts operating to cool the CPU 111, but the temperature of the CPU 111 continues to rise until time t5. During this period, the amount of heat generated by the CPU 111 is larger than the cooling capacity of the cooling unit 115. After time t5, since the difference between the temperature of the CPU 111 and the temperature of the air blown by the cooling unit 115 becomes large, the cooling capacity of the cooling unit 115 exceeds the amount of heat generated by the CPU 111. Therefore, after time t5, the temperature of the CPU 111 begins to decrease. Thereafter, when the temperature of the CPU 111 becomes equal to or lower than the stop threshold value P1, the cooling unit 115 is stopped. Let the period from time t2 when the temperature of the CPU with a low rising rate reaches the start threshold value S1 to time t5 when the temperature begins to decrease be T3. The period T3 is larger than the period T1.

[0061] A case will be described in which a start threshold value S2 and a stop threshold value P2 are determined for a CPU with a low rate of increase. The start threshold value S2 is greater than the start threshold value S1. The start threshold value S2 is greater than the stop threshold value P2.

[0062] For a CPU with a low rate of increase, the temperature rises while the cooling unit 115 is not operating, and at time t4 after time t2, the temperature becomes the start threshold value S2. Thereafter, the cooling unit 115 operates and the cooling of the CPU 111 starts, but the temperature of the CPU 111 continues to rise until time t5. During this period, the amount of heat generated by the CPU 111 is greater than the cooling capacity of the cooling unit 115. After time t5, since the difference between the temperature of the CPU 111 and the temperature of the air blown by the cooling unit 115 increases, the cooling capacity of the cooling unit 115 exceeds the amount of heat generated by the CPU 111. For this reason, after time t5, the temperature of the CPU 111 begins to decrease. Thereafter, when the temperature of the CPU 111 becomes equal to or lower than the stop threshold value P2, the cooling unit 115 is stopped.

[0063] Let the period from time t4 when the temperature of the CPU with a low rate of increase becomes the start threshold value S2 to time t5 when the temperature begins to decrease be T2. The period T2 is shorter than the period T3. For this reason, in a CPU with a low rate of increase, when the start threshold value S2 is applied, the period during which the cooling unit 115 operates becomes shorter compared to the case where the start threshold value S1 determined for a CPU with a high rate of increase is applied.

[0064] FIG. 6 is a flowchart showing an example of the flow of the temperature adjustment process. The temperature adjustment process is a process executed by the CPU 111 included in the MFP 1 by executing a temperature adjustment program stored in the ROM 112, HDD 114, or CD-ROM 117. Referring to FIG. 6, the CPU 111 included in the MFP 1 determines whether or not the power of the MFP 1 has been detected as being turned on. When power is supplied, the CPU 111 executes a boot program or the like, and then executes a temperature adjustment program and a control program for controlling each unit. In step S01, when the execution of the temperature adjustment program is started, the process proceeds to step S02. In step S02, a reference temperature determination process is executed. Details of the reference temperature determination process will be described later, but it is a process of determining a start threshold value S and a stop threshold value P.

[0065] In step S03, an in-operation control process is executed, and the process proceeds to step S04. Details of the in-operation control process will be described later, but when the in-operation control process is executed, the cooling unit 115 is driven while it is detected that the operation panel 6 is being operated by the user. Also, the cooling unit 115 is driven while the automatic document feeder 2, document reading unit 3, image forming unit 4, and paper feeding unit 5 are operating.

[0066] In step S04, it is determined whether or not the cooling unit 115 is stopped. If the cooling unit 115 is stopped, the process proceeds to step S05, otherwise the process proceeds to step S11. When the cooling unit 115 is stopped, the operation panel 6 is not being operated by the user, and the automatic document feeder 2, document reading unit 3, image forming unit 4, and paper feeding unit 5 are not operating. In step S05, the temperature of the CPU 111 is detected, and the process proceeds to step S06. The temperature of the CPU 111 detected by the temperature sensor 116 is acquired.

[0067] In step S06, it is determined whether the temperature detected in step S05 is equal to or higher than the start threshold value S. If the temperature of the CPU 111 is equal to or higher than the start threshold value S, the process proceeds to step S07; otherwise, the process returns to step S03.

[0068] In step S07, the cooling unit 115 is driven, and the process proceeds to step S08. As a result, air is blown from the cooling unit 115 to the CPU 111, and the CPU 111 is cooled. In step S08, the temperature of the CPU 111 is detected, and the process proceeds to step S09. The temperature of the CPU 111 detected by the temperature sensor 116 is acquired. In step S09, it is determined whether the temperature detected in step S08 is equal to or lower than the stop threshold value P. If the temperature of the CPU 111 is equal to or lower than the stop threshold value P, the process proceeds to step S10; otherwise, the process returns to step S08.

[0069] In step S10, the cooling unit 115 is stopped, and the process proceeds to step S11. In step S11, it is determined whether the power of the MFP 1 has been turned off. For example, when the OFF of the main switch is detected, the power OFF of the MFP 1 is detected. If the power OFF of the MFP 1 is detected, the process ends; otherwise, the process returns to step S03.

[0070] FIG. 7 is a flowchart showing an example of the flow of the reference temperature determination process. The reference temperature determination process is a process executed in step S02 of the temperature adjustment process. Referring to FIG. 7, the CPU 111 starts the initial program (step S11) and advances the process to step S12. The initial program includes control programs for controlling each of a plurality of other control units. The initial program also includes application programs installed in the MFP 1.

[0071] In step S12, it is determined whether the temperature can be detected by the temperature sensor 116. The system waits until the temperature can be detected by the temperature sensor 116 (NO in step S12), and when the temperature detection becomes possible (YES in step S12), the process proceeds to step S13.

[0072] In step S13, the CPU 111 causes the temperature sensor 116 to detect the temperature and advances the process to step S14. In step S14, it is determined whether all of the initial programs started in step S11 have been started. If all of the initial programs have been started, the process proceeds to step S15; otherwise, the process returns to step S13.

[0073] In step S15, the rising rate is determined, and the process proceeds to step S16. The rising rate is determined based on the temporal change in the temperature detected by the temperature sensor 116 in step S13. The rising rate is calculated from the temperatures at the start and end of the temperature detection. Note that the rising rate may be the maximum temperature change rate, the minimum temperature change rate, or the average of the temperature change rates between the start and end of the temperature detection.

[0074] In step S16, the start threshold value S is determined, and the process proceeds to step S17. The related table stored in the HDD 114 is referred to, and the start threshold value S associated with the rising rate determined in step S15 is determined.

[0075] In step S17, the stop threshold value P is determined, and the process returns to the temperature adjustment process. The stop threshold value P is determined based on the start threshold value S determined in step S16. The stop threshold value P is determined to be a value smaller than the start threshold value S by a predetermined value. Also, the stop threshold value P may be associated with the rising rate by the association table. In this case, the stop threshold value P is determined in the same manner as the start threshold value S.

[0076] FIG. 8 is a flowchart showing an example of the flow of control processing during operation. The control processing during operation is the processing executed in step S03 of the temperature adjustment processing. Referring to FIG. 8, the CPU 111 determines whether or not the operation panel 6 is being operated by the user (step S21). If the operation panel 6 is being operated by the user, the process proceeds to step S23; otherwise, the process proceeds to step S22. In step S22, it is determined whether or not image formation is in progress. If the image forming unit 4 is operating, the process proceeds to step S23; otherwise, the process proceeds to step S24.

[0077] In step S23, the CPU 111 drives the cooling unit 115 and returns the process to the temperature adjustment process. In step S24, the CPU 111 stops the cooling unit 115 and returns the process to the temperature adjustment process.

[0078] <Modification Example> The cooling capacity of the cooling unit 115 varies depending on the outside air temperature. Therefore, the MFP 1 in the modification example includes an outside air temperature sensor that measures the outside air temperature and corrects the reference temperature based on the outside air temperature.

[0079] FIG. 9 is a block diagram showing an example of the functions of the CPU included in the MFP in the modification example. The difference between the functions shown in FIG. 9 and the functions shown in FIG. 4 is that the reference temperature determination unit 53 is changed to the reference temperature determination unit 53A. Since the other functions are the same as those shown in FIG. 4, the description will not be repeated here.

[0080] In addition to the rising rate determination unit 61, the reference temperature determination unit 53A includes a correction unit 63. The reference temperature determination unit 53A determines a reference temperature based on the rising rate determined by the rising rate determination unit 61. The correction unit 63 corrects the determined reference temperature based on the outside air temperature. The outside air temperature is close to the temperature of the air blown from the cooling unit 115. For this reason, the ability of the cooling unit 115 to cool the CPU 111 is higher when the outside air temperature is low than when it is high. Therefore, when the ability of the cooling unit 115 to cool the CPU 111 is high, the reference temperature can be increased. A correction table associating the outside air temperature with the correction value is stored in advance in the HDD 114. The correction unit 63 refers to the correction table, determines a correction value corresponding to the outside air temperature, and corrects the reference temperature. Thereby, the start threshold value S and the stop threshold value P of the reference temperature are corrected.

[0081] Note that a function for determining the correction value from the air blowing capacity of the cooling unit 115 and the outside air temperature may be prepared in advance, and the correction value may be determined using the function.

[0082] As described above, in the MFP1 according to the present embodiment, the CPU 111 that executes the program determines the reference temperature based on the rising rate of the temperature of the CPU 111 detected by the temperature sensor 116 during the startup period. Then, the CPU 111 operates the cooling unit 115 based on the temperature detected by the temperature sensor 116 and the reference temperature during the actual operation period. Since the rising rate of the temperature may differ due to individual differences of the CPU 111, a reference temperature adapted to the CPU 111 is determined. Also, since the load on the CPU 111 changes due to the difference in the number of units stored in the substrate storage box 100, a reference temperature adapted to the load on the CPU 111 is determined. For this reason, since the cooling unit 115 operates based on the reference temperature suitable for the CPU 111 mounted on the MFP1, it is possible to prevent the cooling unit 115 from operating during a period when cooling is not required, and to prevent the operating noise of the cooling unit 115 from occurring.

[0083] Also, the actual operation period does not include the period during which the operation panel 6 is receiving operations input by the user. Therefore, based on the temperature of the CPU 111 detected while not receiving operations input by the user and the reference temperature, the cooling unit 115 operates. Thus, it is possible to suppress the generation of the operating sound of the cooling unit 115 while the user is not operating.

[0084] Also, the CPU 111 operates the cooling unit 115 on the condition that the cooling unit 115 is not operating during the actual operation period. The cooling unit 115 is operated by the CPU 111 while the operation panel 6 is being operated by the user when the image forming unit 4 is operating. When the CPU 111 is not controlling the image forming unit 4 or the operation panel 6, the CPU 111 can be cooled. Even in this case, when it is not necessary to cool the CPU 111, the generation of the operating sound of the cooling unit 115 can be suppressed.

[0085] Also, the CPU 111 operates the cooling unit 115 while executing the process of causing the image forming unit 4 to form an image. Thus, it is possible to suppress the rise in the temperature of the CPU 111 while the CPU 111 is controlling the image forming unit 4 to form an image.

[0086] In the MFP 1 in the modification example, the CPU 111 corrects the rising rate based on the outside air temperature. The cooling capacity of the cooling unit 115 increases as the outside air temperature decreases. Therefore, since it is possible to determine a reference temperature suitable for the cooling capacity of the cooling unit 115, it is possible to more suppress the generation of the operating sound of the cooling unit 115 as the outside air temperature is lower.

[0087] <Summary of the Embodiment> (Item 1) A processor that executes a program, Cooling means for cooling the processor, Detection means for detecting the temperature of the processor, and The processor determines a reference temperature based on the rate of temperature rise detected by the detection means during the startup period, and operates the cooling means based on the temperature detected by the detection means and the reference temperature during an actual operation period different from the startup period. An image forming apparatus.

[0088] According to this aspect, the reference temperature is determined based on the rate of temperature rise of the processor during the startup period, and the cooling means operates based on the temperature of the processor detected during the actual operation period and the reference temperature. Since the rate of temperature rise varies due to individual differences in the processor, a reference temperature adapted to the processor is determined. If the devices controlled by the processor are different, the load on the processor is also different, so a reference temperature adapted to the load on the processor is determined. For this reason, since the cooling means operates based on a reference temperature suitable for the processor, it is possible to prevent the cooling means from operating during a period when cooling is not necessary, and it is possible to prevent the operating noise of the cooling means from occurring. As a result, it is possible to provide an image forming apparatus that suppresses the generation of noise.

[0089] (Item 2) Further comprising operation reception means for receiving an operation input by a user, The image forming apparatus according to item 1, wherein the actual operation period does not include a period during which the operation reception means receives the operation.

[0090] According to this aspect, the cooling means operates based on the temperature of the processor detected while the operation input by the user is not being received and the reference temperature. For this reason, it is possible to suppress the generation of the operating noise of the cooling means while the user is not operating.

[0091] (Item 3) The image forming apparatus according to item 1 or 2, wherein the processor operates the cooling means on the condition that the cooling means is not operating during the actual operation period.

[0092] In accordance with this aspect, on the condition that the cooling means is not operating, the cooling means operates. When the cooling means operates under other controls, if the cooling means is not operating under other controls, the processor can be cooled. Even in this case, when it is not necessary to cool the processor, the generation of the operating noise of the cooling means can be suppressed.

[0093] (Item 4) The image forming apparatus further includes image forming means for forming an image on a recording medium. The image forming apparatus according to any one of Items 1 to 3, wherein the processor operates the cooling means while executing a process of causing the image forming means, which is one of the device control processes, to form an image.

[0094] In accordance with this aspect, since the processor operates the cooling means while executing a process of causing the image forming means to form an image, an increase in the temperature of the processor during image formation can be suppressed.

[0095] (Item 5) The image forming apparatus further includes outside air temperature detecting means for detecting the outside air temperature. The image forming apparatus according to any one of Items 1 to 4, wherein the processor corrects the reference temperature based on the detected outside air temperature.

[0096] In accordance with this aspect, the rising rate is corrected based on the outside air temperature. The cooling capacity of the cooling means is affected by the outside air temperature. Therefore, a reference temperature suitable for the cooling capacity of the cooling means can be determined.

[0097] (Item 6) A temperature adjustment method executed by a processor for controlling an image forming apparatus, wherein the image forming apparatus includes cooling means for cooling the processor and detecting means for detecting the temperature of the processor, and a determination step of determining a reference temperature based on a rising rate of the temperature detected by the detecting means during a startup period. A temperature adjustment method for causing the processor to execute: a startup step of operating the cooling means based on the temperature detected by the detection means during an actual operation period different from the startup period and the reference temperature.

[0098] According to this aspect, since the cooling means operates based on a reference temperature suitable for the processor, it is possible to prevent the cooling means from operating during a period when cooling is not required, and it is possible to prevent the operating noise of the cooling means from occurring. As a result, it is possible to provide a temperature adjustment method that suppresses the generation of noise.

[0099] (Clause 7) A temperature adjustment program executed by a processor that controls an image forming apparatus, The image forming apparatus includes: a cooling means for cooling the processor; a detection means for detecting the temperature of the processor, a determination step of determining a reference temperature based on the rate of increase in the temperature detected by the detection means during the startup period; a temperature adjustment program for causing the processor to execute: a startup step of operating the cooling means based on the temperature detected by the detection means during an actual operation period different from the startup period and the reference temperature.

[0100] According to this aspect, since the cooling means operates based on a reference temperature suitable for the computer, it is possible to prevent the cooling means from operating during a period when cooling is not required, and it is possible to prevent the operating noise of the cooling means from occurring. As a result, it is possible to provide a temperature adjustment program that suppresses the generation of noise.

[0101] It should be considered that all aspects of the embodiments disclosed this time are illustrative and not restrictive. The scope of the present invention is indicated by the scope of claims rather than the above description, and it is intended that all modifications within the meaning and scope equivalent to the scope of claims are included.

Explanation of Reference Numerals

[0102] 1 MFP, 2 Automatic document feeder, 3 Document reading unit, 4 Image forming unit, 5 Paper feeding unit, 6 Operation panel, 7 Paper output tray, 51 CPU temperature detection unit, 53, 53A Reference temperature determination unit, 55 Cooling control unit, 57 Operation reception unit, 59 Image forming control unit, 61 Rise rate determination unit, 63 Correction unit, 65 Actual operation period determination unit, 100 Substrate storage box, 110 Main control unit, 111 CPU, 112 ROM, 113 RAM, 114 HDD, 115 Cooling unit, 116 Temperature sensor, 117 CD-ROM, 121 Document conveyance control unit, 122 Document reading control unit, 123 Image forming control unit, 124 Paper conveyance control unit, 125 FAX control unit, 126 Communication control unit, 127 Panel control unit, 128 Memory control unit, 129 External storage device, 131 Display unit, 132 Operation unit, 161 Display unit, 163 Operation unit, P, P1, P2 Stop threshold, S, S1, S2 Start threshold.

Claims

1. A processor that executes a program, Cooling means for cooling the processor, Detection means for detecting the temperature of the processor, comprising: The processor determines a reference temperature based on the rate of increase in temperature detected by the detection means during the startup period, and based on the temperature detected by the detection means and the reference temperature during an actual operation period different from the startup period, operates the cooling means, an image forming apparatus.

2. Further comprising operation reception means for receiving an operation input by a user, The actual operation period does not include the period during which the operation reception means receives the operation, the image forming apparatus according to claim 1.

3. The processor operates the cooling means on the condition that the cooling means is not operating during the actual operation period, the image forming apparatus according to claim 1 or 2.

4. Further comprising image forming means for forming an image on a recording medium, The processor operates the cooling means while executing a process of causing the image forming means to form an image, the image forming apparatus according to claim 3.

5. Further comprising outside air temperature detection means for detecting the outside air temperature, The processor corrects the reference temperature based on the outside air temperature detected by the outside air temperature detection means, the image forming apparatus according to claim 1.

6. A temperature adjustment method executed by a processor that controls an image forming apparatus, The image forming apparatus includes cooling means for cooling the processor and detection means for detecting the temperature of the processor, A determination step of determining a reference temperature based on the rate of increase in temperature detected by the detection means during the startup period, and a startup step of operating the cooling means based on the temperature detected by the detection means and the reference temperature during an actual operation period different from the startup period, a temperature adjustment method for causing the processor to execute.

7. A temperature adjustment program executed by a processor that controls an image forming apparatus, The image forming apparatus includes cooling means for cooling the processor and detection means for detecting the temperature of the processor, A determination step of determining a reference temperature based on the rate of increase in temperature detected by the detection means during the startup period, and a startup step of operating the cooling means based on the temperature detected by the detection means and the reference temperature during an actual operation period different from the startup period, a temperature adjustment program for causing the processor to execute. ​ ​ ​ ​

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