Light emission control device

Abstract

Reduce the power consumption of a light emitter such as an LED. 【Solution means】In the first hour TA, the LED emission control unit 321 controls the emission of the LED 310 based on the first duty cycle D1 during the first control time D1, and then controls the emission of the LED 310 based on the second duty cycle D2 during the second control time D2, and then controls the emission of the LED 310 based on the third duty cycle D3 during the third control time D3, ···, and then controls the emission of the LED 310 based on the (N - 1)th duty cycle D N-1 during the (N - 1)th control time D N-1 and then controls the emission of the LED 310 based on the Nth duty cycle D N during the Nth control time D N and D1 < D2 < D3 < ··· < D N-1 < D N and T N < T N-1 < ···

Description

[Technical Field]

[0001] The present invention relates to a light emission control device, and more particularly to a light emission control device that controls the emission of light-emitting elements such as LEDs (Light-Emitting Diodes) in power-saving mode. [Background technology]

[0002] Products that take environmental measures into consideration have become indispensable, and one of these measures is energy conservation. For example, the control circuit for the control unit in power-saving mode disclosed in Patent Document 1 targets laser beam printers and the like, and sets power-saving modes in stages according to the usage situation. By controlling the power supply to multiple LEDs (Light-Emitting Diodes) provided in the control unit in stages according to the usage situation, it controls the multiple LEDs to either be on or off. For example, if the control unit has a first LED, a second LED, and a third LED, and there are a first sleep state, a second sleep state, and a third sleep state as power-saving modes, the control circuit controls the first LED, the second LED, and the third LED to be on in the first sleep state where the amount of power consumption reduction is small, controls the first LED to be off and the second LED and the third LED to be on in the second sleep state where the amount of power consumption reduction is moderate, and controls the first LED and the second LED to be off and the third LED to be on in the third sleep state where the amount of power consumption reduction is large. In this way, the control circuit disclosed in Patent Document 1 aims to save power overall among multiple LEDs by controlling which LEDs to be on and which to be off from among multiple LEDs. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2006-263955 [Overview of the project] [Problems that the invention aims to solve]

[0004] By the way, in addition to LED light emission control aimed at saving power for multiple LEDs as a whole, there is also LED light emission control aimed at saving power for individual LEDs.

[0005] As an example of LED light emission control, in power-saving mode, the control circuit gradually increases the duty cycle during the first hour, making the control time used for controlling LED light emission the same for each duty cycle, and controls the LED light emission based on the duty cycle. In the second hour following the first hour, the control circuit controls the LED light emission based on a duty cycle value greater than the maximum duty cycle in the first hour. In the third hour following the second hour, the control circuit gradually decreases the duty cycle, making the control time used for controlling LED light emission the same for each duty cycle, and controls the LED light emission based on the duty cycle. In the fourth hour following the third hour, the control circuit controls the LED light emission based on a duty cycle value less than the minimum duty cycle in the third hour. The control circuit repeats the above control.

[0006] However, while the above LED light emission control method does reduce the power consumption of the LEDs, it cannot be said that it sufficiently reduces the power consumption of the LEDs.

[0007] This invention has been made in view of the above circumstances, and aims to further reduce the power consumption of light-emitting elements such as LEDs. [Means for solving the problem]

[0008] A light emission control device according to one aspect of the present invention is a light emission control device comprising a light emission control unit that controls the emission of light from a light emitter based on a duty cycle, wherein in a first time, the light emission control unit uses the nth duty cycle, which has a value in ascending order of n (where n is an integer from 1 to N, and N is an integer of 2 or more), to control the emission of light from the light emitter, in ascending order of nth duty cycle, and shortens the nth control time for which the nth duty cycle is used to control the emission of light from the light emitter as the value of the nth duty cycle increases, and controls the emission of light from the light emitter for the nth control time based on the nth duty cycle, and in a second time following the first time, The emission of light from the light source is controlled based on a duty cycle with a value greater than the nth duty cycle. In the third time following the second time, the nth duty cycles are used to control the emission of light from the light source in descending order of value, with the nth control time being shortened for larger nth duty cycles. The emission of light from the light source is controlled for the nth control time based on the nth duty cycle. In the fourth time following the third time, the emission of light from the light source is controlled based on a duty cycle with a value smaller than the first duty cycle. [Effects of the Invention]

[0009] According to the present invention, in the process of gradually increasing the duty cycle value in the first time and in the process of gradually decreasing the duty cycle value in the third time, the larger the duty cycle value, the shorter the control time used to control the emission of light from the light source, thus further reducing the power consumption of the light source. [Brief explanation of the drawing]

[0010] [Figure 1] This is a perspective view showing the external appearance of an image forming apparatus equipped with a light emission control device according to one embodiment of the present invention. [Figure 2] Figure 1 is a block diagram schematically showing the internal configuration of the image forming apparatus. [Figure 3]This figure shows the external appearance of the control panel in Figure 1. [Figure 4] This is a block diagram schematically showing the internal configuration of the control unit in Figure 3. [Figure 5] This diagram illustrates the LED light emission control by the LED light emission control unit shown in Figure 4 during power saving mode. [Figure 6] This diagram illustrates the LED light emission control by the LED light emission control unit in Figure 4 during power saving mode, and shows a detailed view of a part of Figure 5. [Figure 7] This figure illustrates the LED light emission control in power-saving mode in a comparative example, compared to the LED light emission control in power-saving mode shown in Figure 6. [Figure 8] This figure shows an example of the settings screen for controlling LED illumination in power-saving mode. [Modes for carrying out the invention]

[0011] The following describes a light-emitting control device according to one embodiment of the present invention, with reference to the drawings.

[0012] First, an image forming apparatus 100 equipped with an LED light-emitting control device 320 according to one embodiment of the present invention will be described with reference to Figures 1 and 2. Figure 1 is a perspective view showing the external appearance of the image forming apparatus 100 equipped with an LED light-emitting control device 320 according to one embodiment of the present invention. Figure 2 is a block diagram schematically showing the internal configuration of the image forming apparatus 100 of Figure 1. The image forming apparatus 100 is a multifunction device that combines multiple functions such as facsimile, copying, printing, and scanning. Note that the image forming apparatus 100 is not limited to a multifunction device, and may be a printer or the like.

[0013] The housing 101 of the image forming apparatus 100 houses multiple devices for realizing the various functions of the image forming apparatus 100. For example, the housing 101 houses the image reading unit 102, the image forming unit 103 (see Figure 2), the fixing unit 104 (see Figure 2), and the paper feeding unit 105, etc.

[0014] The image reading unit 102 is an ADF (Auto Document Feeder) that includes a document transport unit 106 for transporting documents and a scanner that optically reads documents transported by the document transport unit 106 or documents placed on a contact glass (not shown). The image reading unit 102 reads an image from the document and acquires image data by illuminating the document with a light irradiation unit and receiving the reflected light with a CCD sensor.

[0015] The image forming unit 103 includes a photosensitive drum, a charging device, an exposure device, a developing device, and a transfer device. The image forming unit 103 forms a toner image on the recording paper supplied from the paper feeding unit 105 based on image data acquired by the image reading unit 102, or image data sent from a personal computer and other facsimile devices connected via a network line.

[0016] The fuser unit 104 heats the recording paper on which a toner image has been formed by the image forming process of the image forming unit 103, and performs a fixing process to fix the toner image to the recording paper by thermal compression. After the fixing process by the fuser unit 104, the image-formed recording paper is discharged to the paper discharge unit 107. The paper discharge unit 107 includes a paper discharge tray 108 on which the discharged image-formed recording paper is placed. The paper feed unit 105 pulls out recording paper one sheet at a time from the paper feed cassette or from the manual feed tray and sends it to the image forming unit 103.

[0017] The image forming apparatus 100 includes an operation unit 109 located near the image reading unit 102 and on the front side of the image forming apparatus 105. The operation unit 109 receives instructions input by the user via the operation unit 109 regarding processing related to various functions that the image forming apparatus 100 can perform.

[0018] The image forming apparatus 100 includes a display unit 110. In this embodiment, the portion of the operation unit 109 configured as a pointing device and the display device 110 are combined into a touch panel (touchscreen). The display unit 110, under the control of the control unit 121, displays various GUI (Graphical User Interface) screens for the user to perform various operations on the various functions of the image forming apparatus 100, such as a home screen, login screen, copy screen, transmission screen, and job history screen.

[0019] The image processing unit 111 includes an image processing circuit and performs image processing on the image data acquired by the image reading unit 102 as needed. The image memory 112 includes an area for temporarily storing the image data acquired by the image reading unit 102. For example, the image memory 112 temporarily stores the image data that is the target of image formation by the image forming unit 103.

[0020] The storage unit 113 is a high-capacity storage device such as an HDD (Hard Disk Drive) or SSD (Solid State Drive), and is a high-capacity storage device that stores various data, including image data read by the storage unit 113. The storage unit 113 also stores various computer programs, such as control programs, for realizing the operation of the image forming apparatus 100.

[0021] The facsimile communication unit 114 is a facsimile communication mechanism that connects to a public network and transmits and receives image data via the public network. The network interface unit 115 is the interface to the network. The control unit 121 transmits and receives signals with external devices such as personal computers on the network via this network interface unit 115.

[0022] The image forming apparatus 100 includes a control unit 120. The control unit 120 includes a processor, RAM (Random Access Memory), and ROM (Read Only Memory), etc. The processor is, for example, a CPU (Central Processing Unit), an MPU (Micro Processing Unit), or an ASIC (Application Specific Integrated Circuit).

[0023] The control unit 120 includes a control unit 121. The control unit 120 functions as a control unit 121 through the operation of the processor according to the control program stored in the memory unit 113. However, the control unit 121 and other components can also be configured by hardware circuits, rather than by operation according to the control program of the control unit 120. The same applies to each embodiment below unless otherwise specified.

[0024] The control unit 120 is electrically connected to the document transport unit 106, image reading unit 102, image forming unit 103, fixing unit 104, paper feeding unit 105, operation unit 109, image processing unit 111, image memory 112, storage unit 113, facsimile communication unit 114, and network interface unit 115, etc. The control unit 121 is responsible for the overall control of the image forming apparatus 100.

[0025] Each part of the image forming apparatus 100 is connected to a power supply (not shown), and each part of the image forming apparatus 100 operates by power supplied from this power supply. In this embodiment, the control unit 121 controls the power supply to each part of the image forming apparatus 100. When predetermined conditions are met, such as no image forming process being performed for a predetermined period of time, the control unit 121 stops or limits the power supply to each part of the image forming apparatus 100, thereby transitioning the state of the image forming apparatus 100 from a state in which processing related to various functions of the image forming apparatus 100 can be quickly executed (hereinafter referred to as "normal mode") to a power-saving state with low power consumption (hereinafter referred to as "power-saving mode"). Furthermore, when predetermined conditions are met, such as an operation being performed on the operation unit 109, the control unit 121 performs a recovery process from power-saving mode, transitioning the state of the image forming apparatus 100 from power-saving mode to normal mode.

[0026] The control unit 109 in Figure 1 will be described with reference to Figures 3 and 4. Figure 3 is a diagram showing the external appearance of the control unit 109 in Figure 1. Figure 4 is a block diagram schematically showing the internal configuration of the control unit 109 in Figure 3.

[0027] As shown in Figure 3, the control unit 109 includes buttons corresponding to the "1" button, "2" button, "3" button, etc., as well as a "C" button corresponding to Clear, buttons corresponding to Reset, Stop, and Start, and a button corresponding to Energy Saver. Each button is made of a light-transmitting material. As shown in Figure 4, the control unit 109 includes an LED (Light-Emitting Diode) 310 that illuminates each button from the back, and an LED light emission control device 320 as an example of a light emission control device. Although Figure 4 shows one LED 310, the number of LEDs 310 is not particularly limited.

[0028] The LED control device 320 includes an LED light emission control unit 321 as an example of a light emission control unit, a FET (Field Effect Transistor) 322, and a resistor element 323.

[0029] FET322 is an N-channel MOSFET, with a PWM signal output by the LED light emission control unit 321 supplied to its gate, the cathode of the LED 310 connected to its drain, and one end of the resistor 323 connected to its source. FET322 is an example of a switching circuit and could be, for example, an NPN bipolar transistor. The LED 310 has the power supply voltage Vcc connected to its anode and the drain of FET322 connected to its cathode. The resistor 323 has the source of FET322 connected to one end and ground (GND) connected to the other end.

[0030] The LED light emission control unit 321 is, for example, a microcontroller, and the CPU constituting the microcontroller controls the illumination of the LED 310 by operating according to a program that controls the illumination of the LED 310, for example, written to the memory constituting the microcontroller. The LED light emission control unit 321 controls the illumination of the LED 310 by PWM (Pulse Width Modulation) and supplies a PWM signal that rapidly alternates between on (high-level voltage) and off (low-level voltage) to the gate of the FET 322. When the PWM signal is at a high-level voltage, the FET 322 turns on (conducts) and the LED 310 lights up, while when the PWM signal is at a low-level voltage, the FET 322 turns off (does not conduct) and the LED 310 turns off.

[0031] In PWM, the ratio of the duration of one high-level voltage to one period (the sum of the duration of one high-level voltage and one low-level voltage) is called the "duty cycle" or "duty ratio." However, the duty cycle (duty ratio) is usually expressed as a percentage or decimal value. For example, if one period is 0.005 seconds and the duration of one high-level voltage (pulse width) is 0.0025 seconds, the duty cycle (duty ratio) is expressed as 50% (percentage) or 0.5 (decimal value).

[0032] The larger the duty cycle value, the longer the power supply time to the LED310 per cycle, resulting in higher brightness and greater power consumption by the LED310. Conversely, the smaller the duty cycle value, the shorter the power supply time to the LED310 per cycle, resulting in lower brightness and less power consumption by the LED310.

[0033] In normal mode (when the control unit 121 of the control unit 120 notifies the LED light emission control unit 321 of normal mode operation), for example, it supplies a PWM signal with a duty cycle of 1 (decimal notation) to the base of the FET 322, causing the FET 322 to be constantly on (conductive) and the LED 310 to be constantly lit.

[0034] The LED light emission control unit 321 controls the light emission of the LED 310 in power-saving mode when it receives notification of power-saving mode operation from the control unit 121 of the control unit 120. The light emission control of the LED 310 in power-saving mode by the LED light emission control unit 321 is described below.

[0035] The LED light emission control unit 321 lowers the clock frequency in power-saving mode compared to the clock frequency in normal mode and repeatedly performs the following light emission control in sequence: 1st time, 2nd time, 3rd time, and 4th time (firefly control).

[0036] The LED light emission control unit 321 controls the light emission of the LED 310 based on the duty cycle.

[0037] In the first time, the LED light emission control unit 321 uses the nth duty cycle, which has a value in ascending order of n (where n is an integer between 1 and N, and N is an integer of 2 or more), to control the light emission of the LED 310, and shortens the nth control time for which the nth duty cycle is used to control the light emission of the LED 310 as the value of the nth duty cycle increases. Based on the nth duty cycle, the LED 310 is controlled to emit light for the duration of the nth control time (light emission control in the first time).

[0038] The LED light emission control unit 321 controls the light emission of the LED 310 in the second time period following the first time period based on a duty cycle (the N+1 duty cycle) that is greater than the N duty cycle (light emission control in the second time period).

[0039] In the third time following the second time, the LED light emission control unit 321 uses the n duty cycles in descending order of value to control the light emission of the LED 310, shortening the n control time for which the n duty cycle is used to control the light emission of the LED 310 as the value of the n duty cycle increases, and controls the light emission of the LED 310 for the n control time based on the n duty cycle (light emission control in the third time).

[0040] The LED light emission control unit 321 controls the light emission of the LED 310 in the fourth time period following the third time period, based on a duty cycle (zero duty cycle) with a smaller value than the first duty cycle (light emission control in the fourth time period).

[0041] The light emission control of the LED 310 in power-saving mode by the LED light emission control unit 321 will be explained in detail with reference to Figures 5 and 6. Figure 5 is a diagram illustrating the light emission control of the LED 310 in power-saving mode by the LED light emission control unit 321 in Figure 4. Figure 6 is a diagram illustrating the light emission control of the LED 310 in power-saving mode by the LED light emission control unit 321 in Figure 4, and is a diagram showing a part of Figure 5 in detail.

[0042] In the first hour TA and the third hour TC, the LED light emission control unit 321 uses, as the duty cycle, the nth (where n is each integer from 1 to N, and N is an integer of 2 or more) duty cycle D N-1 (N duty cycles from the first duty cycle D1 to the Nth duty cycle D N ). The nth duty cycle D n has a larger value as n increases (the first duty cycle D1 < the second duty cycle D2 < the third duty cycle D3 < ··· < the (N - 1)th duty cycle D N-1 < the Nth duty cycle D N ).

[0043] Also, in the first hour TA and the third hour TC, the LED light emission control unit 321 makes the nth control time T n (where n is each integer from 1 to N, and N is an integer of 2 or more) shorter as the value of the nth duty cycle D n is larger, which is used for controlling the light emission of the LED 310 (the Nth control time T n < the (N - 1)th control time T N < ··· < the third control time T3 < the second control time T2 < the first control time T1).

[0044] In the first hour TA (the time when the brightness of the LED 310 is gradually increased), the LED light emission control unit 321 controls the light emission of the LED 310 based on the first duty cycle D1 during the first control time T1, and then controls the light emission of the LED 310 based on the second duty cycle D2 during the second control time T2, and then controls the light emission of the LED 310 based on the third duty cycle D3 during the third control time T3, ···, and then controls the light emission of the LED 310 based on the (N - 1)th duty cycle D N-1 during the (N - 1)th control time T N-1 , and then controls the light emission of the LED 310 based on the Nth duty cycle D N during the Nth control time T N (the light emission control in the first hour).

[0045] ​​During the second time TB (the time during which the LED 310 is maintained at a constant high brightness), the LED light emission control unit 321 operates on the Nth duty cycle D during the second time TB. N The N+1st duty cycle D with a larger value N+1 The LED light emission is controlled based on this (light emission control during the second time period).

[0046] During the third time TC (TC=TA) (the time during which the brightness of LED310 is gradually reduced), the LED light emission control unit 321 controls the Nth control time T N During the Nth duty cycle D N Based on this, the light emission of LED310 is controlled, followed by the (N-1) control time T N-1 During the N-1 duty cycle D N-1 Based on this, the light emission control of LED310 is performed, ..., then, during the third control time T3, the light emission control of LED310 is performed based on the third duty cycle D3, then, during the second control time T2, the light emission control of LED310 is performed based on the second duty cycle D2, and then, during the first control time T1, the light emission control of LED310 is performed based on the first duty cycle D1 (light emission control in the third time).

[0047] During the fourth time TD (the time during which the LED 310 is kept at a constant low brightness), the LED light emission control unit 321 controls the light emission of the LED 310 based on the 0th duty cycle D0, which is smaller than the 1st duty cycle D1, during the fourth time TD (light emission control during the fourth time).

[0048] The LED light emission control unit 321 repeatedly performs the light emission control in the first time period, the second time period, the third time period, and the fourth time period in sequence (firefly control).

[0049] For example, the first time interval TA = the third time interval TC = 1 second, the second time interval TB = 0.1 seconds, and the fourth time interval TD = 2 seconds.

[0050] Next, the nth control time T mentioned above. nAn example of (n is each integer from 1 to N, and N is an integer of 2 or more) will be described. In the first hour TA and the third hour TC, N is 2 or more, and D1 < D2 < D3 < ··· < D N-1 <D N and, T N <T N-1 < ··· < T3 < T2 < T1 are satisfied, and N, the nth duty cycle D n , the nth control time T n are set, it is not limited to the following content.

[0051] The first hour TA and the third hour TC (TC = TA) are defined as the time S(G(N)). Also, the nth control time T n (n is each integer from 1 to N, and N is an integer of 2 or more) is defined as the control time k / (G(n) × a) (T1 is defined as k / (G(1) × a), T2 is defined as k / (G(2) × a), T3 is defined as k / (G(3) × a), ···, T N-1 is defined as k / (G(N - 1) × a), and T<000003o>is defined as k / (G(N) × a)). The coefficient G(n) is a function with n as a variable, and the coefficients k and a are constants.

[0052] The time S(G(N)) can be expressed as the following (Equation 1) using the control time k / (G(n) × a). [[ID=2R]]

[0053]

Equation

[0054] When n is each integer from of 2 or more), the control time T n = k / (G(n) × a) is set to be greater than the reciprocal of the number of pulses in the time S(G(N)) (seconds) and less than the time S(G(N)) (seconds). When the time S(G(N)) = 1 (s) and the number of pulses in the time S(G(N)) = 1 (second) = 200, the selection conditions for the coefficients k, G(n), and a are the following (Equation 2).

[0055] It should be noted that there seem to be some incorrect tags in the original text (such as <000003o> which should probably be N ), but I translated it as accurately as possible according to the rules.

number

[0056] Using the coefficients k, G(n), and a that satisfy the above equation (2), the nth control time T is determined for each of n (where n is an integer between 1 and N, and N is an integer greater than or equal to 2). n The LED light emission control unit 321 sets the nth duty cycle D in the first time TA. n The values ​​are used in ascending order, and the set nth control time T is used. n During the nth duty cycle D n Based on this, the LED 310's light emission control is performed. In addition, the LED light emission control unit 321 controls the nth duty cycle D during the third time TC. n The values ​​are used in descending order, and the set nth control time T is used. n During the nth duty cycle D n The light emission of LED310 is controlled based on the following. In this case, the nth duty cycle D n For example, when N=9, this is 0.1 × n (decimal value) (1st duty cycle D1=0.1 (decimal value), 2nd duty cycle D2=0.2 (decimal value), 3rd duty cycle D3=0.3 (decimal value), ..., 8th duty cycle D8=0.8 (decimal value), 9th duty cycle D9=0.9 (decimal value)).

[0057] Next, the nth control time T mentioned above. n Let's explain Specific Example 1 of (where n is an integer between 1 and N, and N is an integer greater than or equal to 2). In Specific Example 1, N=9, time S(G(n))=1 (seconds), and the nth duty cycle D n Let = 0.1 × n (decimal value) (1st duty cycle D1 = 0.1 (decimal value), 2nd duty cycle D2 = 0.2 (decimal value), 3rd duty cycle D3 = 0.3 (decimal value), ..., 8th duty cycle D8 = 0.8 (decimal value), 9th duty cycle D9 = 0.9 (decimal value)).

[0058] In specific example 1, we set the coefficients k and G(n) to k=1 and G(n)=n, and in this case, the coefficient a can be calculated by the following equation (Equation 3), resulting in a=2.8289.

[0059]

number

[0060] In specific example 1, the coefficients k, G(n), and a are k=1, G(n)=n, and a=2.8289. In this case, for each integer n between 1 and 9, the nth control time T n is, T n = 1 / (n × 2.8289)(s). n is an integer between 1 and 9, and the nth duty cycle D n If the period is 0.005 seconds (200 pulses per second), then the nth duty cycle D n The nth pulse number corresponding to PL n PL n =T n This becomes / 0.005 (pulse).

[0061] The first control time T1 and the first pulse number PL1 corresponding to the first duty cycle D1 = 0.1 (decimal value) can be calculated as shown in (Equation 4) below.

[0062]

number

[0063] The second control time T2 and pulse count PL2 corresponding to the second duty cycle D2 = 0.2 (decimal value) can be calculated as shown in (Equation 5) below.

[0064]

number

[0065] The ninth control time T9 and pulse count PL9, corresponding to the ninth duty cycle D9 = 0.9 (decimal value), can be calculated as shown in (Equation 6) below.

[0066]

number

[0067] Power consumption P of LED310 at the first hour TA and third hour TC in specific example 1. NEW1 This can be calculated by the following (equation 7), P NEW1 = 0.32 × Pmax (kWs). However, Pmax is the power consumption of the LED310 when the duty cycle is 1.0 (decimal value).

[0068]

number

[0069] In the specific example 1 above, the first time TA and the third time TC are set to TA=TB=1(s), the second time TB to TB=0.1(s), and the fourth time TD to TD=2(s), and the LED light emission control unit 321 controls the light emission of the LED 310 as follows, for example.

[0070] During the first time period TA=1 (second), the LED light emission control unit 321 controls the light emission of the LED 310 based on the first duty cycle D1=0.1 (decimal value) for a first control time T1=0.353 (seconds), then controls the light emission of the LED 310 based on the second duty cycle D2=0.2 (decimal value) for a second control time T2=0.177 (seconds), ... and then controls the light emission of the LED 310 based on the ninth duty cycle D9=0.9 (decimal value) for a ninth control time T9=0.04 (seconds) (light emission control during the first time period).

[0071] At the second time TB = 0.1 (seconds), the LED light emission control unit 321 will set the 10th duty cycle D to a value greater than the 9th duty cycle D9 = 0.9 (decimal value) during the second time TB.10 The LED light emission is controlled based on =1.0 (decimal value) (light emission control during the second time interval).

[0072] During the third time period TC=1 (second), the LED light emission control unit 321 controls the light emission of the LED 310 based on the ninth duty cycle D9=0.9 (decimal value) for the ninth control time T9=0.04 (seconds), ..., then controls the light emission of the LED 310 based on the second duty cycle D2=0.2 (decimal value) for the second control time T2=0.177 (seconds), and then controls the light emission of the LED 310 based on the first duty cycle D1=0.1 (decimal value) for the first control time T1=0.353 (seconds) (light emission control during the third time period).

[0073] During the fourth time interval TD=2 (seconds), the LED light emission control unit 321 controls the light emission of the LED 310 based on the 0th duty cycle D0=0.0 (decimal value), which is smaller than the 1st duty cycle D1=0.1 (decimal value) (light emission control during the fourth time interval).

[0074] The LED light emission control unit 321 repeatedly performs the light emission control in the first time period, the second time period, the third time period, and the fourth time period in sequence (firefly control).

[0075] The following describes the LED light emission control in power-saving mode in a comparative example compared to the LED light emission control in power-saving mode in this embodiment, as explained using Figure 6, with reference to Figure 7. Figure 7 is a diagram illustrating the LED light emission control in power-saving mode in a comparative example compared to the LED light emission control in power-saving mode in Figure 6.

[0076] The light emission control of the LED in the power-saving mode in this embodiment and the light emission control of the LED in the power-saving mode in the comparative example differ in the time (the first time TA, TAC) for gradually increasing the brightness of the LED 310 and the time (the third time TC, TCC) for gradually decreasing the brightness of the LED 310, and are the same in the time (the second time TB, TBC) for keeping the LED 310 at a constant high brightness and the time (the fourth time TD, TDD (not shown)) for keeping the LED 310 at a constant low brightness.

[0077] In the first time TA for gradually increasing the brightness of the LED 310 and the third time TC for gradually decreasing the brightness of the LED 310, the LED light emission control unit 321 of this embodiment has the nth duty cycle D n (n is each integer from 1 to N, and N is an integer of 2 or more), and the larger the value of the nth duty cycle D n is, the shorter the nth control time T n used for controlling the light emission of the LED 310 (T N < T N-1 < ··· < T3 < T2 < T1). On the contrary, in the first time TAC for gradually increasing the brightness of the LED 310 and the third time TCC for gradually decreasing the brightness of the LED 310, the LED light emission control unit of the comparative example makes the nth duty cycle D n (n is each integer from 1 to N, and N is an integer of 2 or more) the same as the nth control time T n used for controlling the light emission of the LED 310 (T N = T N-1 = ··· = T3 = T2 = T1), and sets it as the control time T C .

[0078] In the first time TAC (the time for gradually increasing the brightness of the LED 310), the LED light emission control unit of the comparative example uses the nth (n is each integer from 1 to N, and N is an integer of 2 or more) duty cycle D n in ascending order of values, and during the control time T C , performs light emission control of the LED 310 based on the first duty cycle D1, and then, during the control time T1 C , performs light emission control of the LED 310 based on the second duty cycle D2, and then, during the control time TC During this time, the illumination of LED310 is controlled based on the third duty cycle D3, and then the control time T C During the N-1 duty cycle D N-1 Based on this, the light emission of LED310 is controlled, followed by the control time T1 C During the Nth duty cycle D N Based on this, the light emission control of LED310 is performed (light emission control in the first time period).

[0079] During the second TBC (time to maintain a constant high brightness of LED310), the LED light emission control unit of the comparative example operates during the second TBC, performing the Nth duty cycle D N The N+1st duty cycle D with a larger value N+1 The LED light emission is controlled based on this (light emission control during the second time period).

[0080] During the third TCC (TCC=TAC) (the time during which the brightness of LED310 is gradually reduced), the LED light emission control unit of the comparative example operates on the nth duty cycle D (where n is an integer between 1 and N, and N is an integer greater than or equal to 2). n The values ​​are used in descending order, and the control time T C During the Nth duty cycle D N Based on this, the light emission of LED310 is controlled, followed by a control time T. C During the N-1 duty cycle D N-1 Based on this, the light emission of LED310 is controlled, and then the control time T C During this time, the illumination of LED310 is controlled based on the third duty cycle D3, followed by a control time T. C During this time, the illumination of LED310 is controlled based on the second duty cycle D2, followed by a control time T. C During this time, the illumination of LED310 is controlled based on the first duty cycle D1 (illumination control in the third time).

[0081] At the fourth time TDC (the time to keep LED 310 at a constant low brightness), the LED emission control unit of the comparative example performs emission control of LED 310 based on the 0th duty cycle D0 whose value is smaller than the 1st duty cycle D1 during the fourth time TDC (emission control at the fourth time).

[0082] The LED emission control unit of the comparative example repeatedly performs the above emission control at the first time, the above emission control at the second time, the above emission control at the third time, and the above emission control at the fourth time in order (firefly control).

[0083] In the comparative example, when N = 9, the nth (n is each integer from 1 to 9) duty cycle D n = 0.1×n (decimal notation), control time T C (= T N = T N-1 = ··· = T3 = T2 = T1) = 0.1 (s), the power consumption P of LED 310 at each of the first time TAC and the third time TCC OLD can be calculated by the following (Equation 8), and P OLD = 0.45×Pmax (kWs). However, Pmax is the power consumption of LED 310 when the duty cycle is 1.0 (decimal notation). Note that when the period of the nth duty cycle D n (n is each integer from 1 to 9) is 0.005 (seconds) (the number of pulses in 1 (second) is 200), the nth pulse number PL n corresponding to the nth duty cycle D n is PL n = T C / 0.005 (pulses) = 20 (pulses). Also, it is assumed that the second time TBC in the comparative example is the same as the second time TB in the first specific example of the embodiment.

[0084]

Equation

[0085] The power consumption reduction rate Δ(%) of the light emission control of LED310 in Specific Example 1 of this embodiment compared to the light emission control of LED310 in the comparative example can be calculated by the following equation (Equation 9), resulting in Δ = 28.8(%). Thus, Specific Example 1 of this embodiment can reduce power consumption by 28.8(%) compared to the comparative example.

[0086]

number

[0087] According to the embodiment described above, in the process of gradually increasing the duty cycle value in the first time TA and in the process of gradually decreasing the duty cycle value in the third time TC, the larger the duty cycle value, the shorter the control time used to control the light emission of the LED 310, thus further reducing the power consumption of the LED 310.

[0088] Furthermore, in the power-saving control of the LED 310 by the LED light emission control unit 321, the duty cycle can be gradually increased or decreased to prevent the human eye from perceiving flickering.

[0089] Furthermore, the present invention is not limited to the configurations of the above embodiments, and various modifications are possible.

[0090] For example, in addition to Specific Example 1 described in the above embodiment, Specific Examples 2 and 3 below can also be given.

[0091] In specific example 2, for the first time TA and the third time TC, when N=9 and S(G(n))=1 (seconds), the coefficients k, G(n), and a are given as k=1 and G(n)=n 2 And a = 1.5397, in this case, for each integer n between 1 and 9, the nth control time T n is, T n = 1 / (n 2is (×1.5397). Also, for each integer n from 1 to 9, the nth duty cycle D n is n = 0.1×n (in decimal notation) (the first duty cycle D1 = 0.1 (in decimal notation), the second duty cycle D2 = 0.2 (in decimal notation), ···, the ninth duty cycle D9 = 0.9 (in decimal notation)).

[0092] The power consumption P of the LED 310 at the first hour TA and the third hour TC in the specific example 2 NEW2 can be calculated by the following (Equation 10), and P NEW2 = 0.18×Pmax (kWs). Here, Pmax is the power consumption of the LED 310 when the duty cycle is 1.0 (in decimal notation).

[0093]

Equation

[0094] The reduction rate Δ (%) of the power consumption of the light emission control of the LED 310 in the specific example 2 above with respect to the light emission control of the LED 310 in the comparative example can be calculated by the following (Equation 11), and Δ = 60.0 (%). The specific example 2 of the present embodiment can reduce the power consumption by 60.0 (%) with respect to the comparative example.

[0095]

Equation

[0096] In the specific example 3, regarding the first hour TA and the third hour TC, when N = 9 and S(G(n)) = 1 (second), the coefficient k, the coefficient G(n), and the coefficient a are set as k = 1, G(n) = n 3 and a = 1.1965. In this case, for each integer n from 1 to 9, the nth control time T n is n = 1 / (n 3 ×1.1965). Also, for each integer n from 1 to 9, the nth duty cycle D n sisn = 0.1 × n (decimal value) (1st duty cycle D1 = 0.1 (decimal value), 2nd duty cycle D2 = 0.2 (decimal value), ..., 9th duty cycle D9 = 0.9 (decimal value)).

[0097] Power consumption P of LED310 at the 1st hour TA and 3rd hour TC in specific example 3. NEW3 This can be calculated by the following (equation 12), P NEW3 = 0.13 × Pmax (kWs). However, Pmax is the power consumption of the LED310 when the duty cycle is 1.0 (decimal value).

[0098]

number

[0099] The power consumption reduction rate Δ(%) of the light emission control of LED310 in Specific Example 3 above compared to the light emission control of LED310 in the Comparative Example can be calculated by (Equation 13) below, resulting in Δ = 71.1(%). Thus, Specific Example 2 of this embodiment can reduce power consumption by 60.0(%) compared to the Comparative Example.

[0100]

number

[0101] Furthermore, multiple firefly controls (hereinafter referred to as "firefly control" as appropriate) may be provided, allowing the user of the image forming apparatus 100 to choose whether or not to use firefly control for controlling the light emission of LEDs in power-saving mode, and if the user chooses to use firefly control, they may also be able to select from among the multiple firefly controls to use for controlling the light emission of LEDs.

[0102] The control unit 121 of the control unit 120 of the image forming apparatus 100 displays a setting screen for LED light emission control in power saving mode, as shown in Figure 8, on the display unit 110. The setting screen shown in Figure 8 includes radio buttons for "use" and "do not use" to select whether or not to use the firefly control in power saving mode. If four firefly control options are available, the setting screen also includes radio buttons for the first firefly control (power saving level 1), the second firefly control (power saving level 2), the third firefly control (power saving level 3), and the fourth firefly control (power saving level 4) to select one of the four firefly control options when the use of the firefly control is selected. The setting screen also includes an "OK" button to confirm the selected settings and a "CANCEL" button to cancel the settings.

[0103] If you choose not to use the firefly control, LED310 will be off during power saving mode. The first firefly control (power saving level 1) is the firefly control of Comparative Example 1 above (variable G(n)=1, variable k=0.1, a=1). The second firefly control (power saving level 2) is the firefly control of Specific Example 1 above (variable G(n)=n, variable k=1, a=2.8289). The third firefly control (power saving level 3) is the firefly control of Specific Example 2 above (variable G(n)=n 2 (variable k=1, a=1.5397). The fourth firefly control (power saving level 4) is the firefly control (variable G(n)=n) of the above example 3. 3 (where k=1 and a=1.1965).

[0104] The user uses the operation unit 109 to select whether or not to use firefly control in power saving mode. If the user selects to use firefly control, they select one firefly control (one power saving level) from the four firefly control options (power saving levels 1 to 4) and then select either the "OK" button or the "CANCEL" button. Based on the signal input from the operation unit 109, the control unit 121 identifies the user's operation and sets the LED light emission control unit 321 to control the light emission of the LED 310 in power saving mode based on the identified user operation. The LED light emission control unit 321 then performs the set light emission control of the LED 310 in power saving mode. For example, if the user selects to use firefly control in power saving mode, selects the second firefly control (power saving level 2), and selects the "OK" button, the control unit 121 sets the second firefly control (power saving level 2) as the light emission control for the LED 310 in power saving mode to the LED light emission control unit 321, and the LED light emission control unit 321 performs the second firefly control (power saving level 2) for the LED 310 in power saving mode.

[0105] For example, a personal computer (hereinafter referred to as "PC") connected to the image forming apparatus 100 may have its CPU display a setting screen, as shown in Figure 8, on the PC's display unit, and the PC may set the image forming apparatus 100 to control the light emission of the LED 310 in power-saving mode.

[0106] Furthermore, although the above embodiment described the device equipped with the LED light emission control device 320 as an image forming apparatus 100, it is not limited to this, and the device equipped with the LED light emission control device 320 may be a device other than the image forming apparatus 100.

[0107] Furthermore, the configurations and processes shown in the above embodiments using Figures 1 to 7, and the configurations and processes shown in the above modifications (for example, the configuration and process shown in the above modifications using Figure 8) are merely embodiments of one invention, and the present invention is not intended to be limited to these configurations and processes. [Explanation of Symbols]

[0108] 310 LED 320 LED Light Control Device 321 LED Light Emission Control Unit

Claims

1. In a light emission control device equipped with a light emission control unit that controls the emission of light from a light-emitting element based on its duty cycle, The light emission control unit, In the first time, the nth duty cycle, with increasing values ​​for n (where n is an integer between 1 and N, and N is an integer of 2 or more), is used to control the emission of light from the light emitter in ascending order of value, and the nth control time for which the nth duty cycle is used to control the emission of light from the light emitter is shortened for each larger value of the nth duty cycle, and the emission of light from the light emitter is controlled for the nth control time based on the nth duty cycle. In the second time period following the first time period, the emission of light from the light-emitting element is controlled based on a duty cycle that is greater than the N duty cycle. In the third time following the second time, the n duty cycles are used to control the emission of light from the light emitter in descending order of value, and the nth control time for which the nth duty cycle is used to control the emission of light from the light emitter is shortened as the value of the nth duty cycle increases, and the emission of light from the light emitter is controlled for the nth control time based on the nth duty cycle. In the fourth time period following the third time period, the emission of light from the light-emitting element is controlled based on a duty cycle with a value smaller than the first duty cycle. Light emission control device.

2. The light emission control device according to claim 1, wherein N is 9, and the control time for n in each integer between 2 and N is a time determined based on 1 / n of the first control time.

3. The light emission control device according to claim 2, wherein the n duty cycle, where n is an integer between 1 and N, is 0.1 × n when the duty cycle is expressed in decimal form.

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