JP2007143340A - Power device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the fluctuation of a load voltage caused by the changeover of power supply from a main power source to an auxiliary power source, to smoothly control power sharing at the same time of the power supply from the main power source and from the auxiliary power source to a load, and to level the consumption amount of external input power. <P>SOLUTION: A power supply device is provided with a first power source 30 of a constant voltage output that inputs commercial AC power, capacitors 37, 38, and a second power source 26 that inputs the power of the capacitor. An output of the first power source and that of the second power source are connected in parallel to supply both powers from the first power source and the second power source to a load 35 at the same time. The second power source is a constant current power source. Furthermore, the power supply device is provided with a load current detection means 33, and a current instruction means 64 that generates an output current instruction signal (a difference value of an output current upper limit value MCD of the first power source against the load current) of the second power source that corresponds to a load current. The second power source is provided with a current controller 46 that controls the output current of the second power source to an output current value corresponding to the output current instruction signal. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a power supply device including a power storage device and an auxiliary power supply including a power supply circuit that uses the power as an input source in addition to a power supply that uses electric power that is constantly supplied from the outside. However, when a large amount of power is required for the operation of the entire device, commercial AC that supplies the power stored in the power storage device to the DC load so that the AC input power of the device does not exceed the power that can be supplied by the power supply. The present invention relates to a power supply device capable of leveling power consumption. The present invention can be applied to, for example, a backup power supply at the time of interruption of power supply from the outside, a high-load power supply exceeding the external power capacity, or a power supply device that performs leveling of external power consumption, a printer, a copying machine, and a facsimile machine.

JP 2004-236492 A JP-A-2005-221474.

  Japanese Patent Application Laid-Open No. 2004-228688 discloses a power supply device that selectively supplies power of a main power supply and an auxiliary power supply that use power supplied from the outside constantly to a part of the load of the image forming apparatus using a switching circuit, and image formation An apparatus is described. In Patent Document 2, a constant voltage power supply circuit is used as an auxiliary power supply and its output voltage is set higher than the output voltage of the main power supply. A diode that prevents backflow to the main power supply is provided in the power supply line from the main power supply to the load. The output voltage of the auxiliary power supply is applied to the power supply line between the diode and the load via a switch or another diode, and the output voltage of the auxiliary power supply becomes the output voltage of the main power supply. Power is supplied to the load only from the auxiliary power source during the higher period, and power is supplied only from the main power source to the load while the output voltage of the auxiliary power source is lower than the output voltage of the main power source. An image forming apparatus that switches and feeds power from only one side is described.

  In the prior art, the power output circuit of the power storage device, that is, the power supply circuit to the load is configured with a constant voltage power supply. When the output of the auxiliary power supply, which is a constant voltage power supply, is switched and supplied to the load, voltage fluctuation occurs at the time of switching due to the difference between the output voltages of the two constant voltage power supplies. When voltage fluctuation occurs, there is a problem that the operation of the motor that supplies power becomes unstable and the motor stops or rotation unevenness occurs. Uneven rotation of the motor causes an image abnormality of the image forming apparatus. As an example, in the case of a color image forming apparatus, color misregistration occurs.

  In addition, when power is supplied from the auxiliary power supply to only a part of the load by the switching circuit, it is necessary to divide the load into a group that switches power supply as such and a group that supplies power only from the main power supply. This grouping is appropriate for the equipment unit or electrical circuit unit to which the load belongs, but it may not be optimal power distribution (load classification), and the storage capacitor in the auxiliary power supply is required. Problems arise such as an increase in capacity and insufficient leveling of consumption of AC power, which is external input power.

  The first object of the present invention is to prevent fluctuations in the load voltage due to switching between power feeding from the main power source and power feeding from the auxiliary power source to the load, and power feeding from the main power source and auxiliary power to the load. A second object is to smoothly control power sharing at the same time for power supply from a power source, and a third object is to smoothen the leveling of external input power consumption more smoothly.

(1) First power source (30) having a constant voltage output using externally supplied power as an input source, power storage device (37, 38), and power of the power storage device (37, 38) as an input source In a power supply device comprising a second power source (26),
The output of the first power source (30) and the output of the second power source (26) are connected in parallel, and both the power from the first power source (30) and the power from the second power source (26) are loaded simultaneously (35 A power supply device.

  In order to facilitate understanding, symbols in parentheses corresponding to the embodiments shown in the drawings or described later or corresponding elements are added for reference. The same applies to the following.

  The output of the first power source (30) and the output of the second power source (26) are connected in parallel, and both the power from the first power source (30) and the power from the second power source (26) are loaded simultaneously (35 ), There is no switching of load power supply from one to the other, and load voltage fluctuations due to switching do not occur. By operating the power sharing of the simultaneous power feeding of the first power source (30) and the second power source (26), the consumption of external power can be leveled more smoothly.

  (2) The power storage device according to (1), wherein the power storage device (37, 38) includes a capacitor (37).

  (3) The power supply device according to (2), wherein the capacitor (37) is an electric double layer capacitor.

  (4) The power storage device according to (2) or (3), wherein the power storage device (37, 38) further includes capacitor charging means (38) for charging the capacitor (37).

  (5) The power supply device according to any one of (1) to (4), wherein the second power supply (26) is a constant current power supply. If the second power source (26) is a constant current power source, the power supplied to the load by the second power source (26) can be adjusted by operating the target current, and the shared power of the second power source (26) can be adjusted. Is easy to control.

  (6) The power supply device further includes a load current detection means (33) for generating a load current signal representing a current value flowing through the load (35) and an output current instruction of the second power supply (26) corresponding to the load current signal. A second power source (26) for controlling the output current of the second power source (26) to an output current value corresponding to the output current instruction signal. The power supply device according to any one of (1) to (5) above.

  According to this, the output current of the second power source (26) is automatically determined corresponding to the load current signal. That is, the shared power of the second power source (26) is automatically determined corresponding to the power load, and excessive consumption of external power or excessive power consumption of the second power source (26) can be easily suppressed.

  (7) The current instruction means (64) uses the difference of the upper limit instruction signal (MCD) that specifies the upper limit of the output current value of the first power supply (30) with respect to the load current signal as the output current instruction signal. The power supply device according to (6), which is provided to the current control means (46). According to this, even if the load current value fluctuates, the output current value of the second power source (26) automatically becomes lower than the load current value, and the output voltage of the second power source (26) becomes excessive. There is no.

  (8) The current instruction means (64) includes D / A conversion means (65) for converting the upper limit instruction data (MCD) into an upper limit instruction signal, and the upper limit instruction signal (MCD) for the load current signal. The difference calculation means (66) which outputs the difference of these to the said current control means (46) as said output current instruction | indication signal, The power supply device as described in said (7). According to this, the output current value (feeding power) of the first power source (30) is defined by the digital data (MCD) representing the upper limit indication value, and the first power source (26) automatically supplies the load power exceeding it. Share it.

  (9) In the above (7) or (8), further comprising control means (20) for controlling energization of the load (35) and supplying the upper limit instruction signal (MCD) to the current instruction means (64). The power supply described.

  (10) The said control means (20) controls the electric current value which the 1st power supply (30) supplies with power to the said load (35) by operating the said upper limit instruction | indication signal (MCD), The said (9) description Power supply.

  (11) The second power source (26) transforms and outputs the electric power of the power storage device (37, 38), controls the output power, the voltage regulator (40, 40a, 40b, 40c), the voltage regulator (40, 40a, 40b, 40c) current detecting means (47) for detecting the output current value, and a control signal for adjusting the output current value to the indicated value of the output current indicating signal is sent to the transformer regulator (40, 40a, 40b). , 40c), and the constant current output of the transformer regulator (40, 40a, 40b, 40c) is supplied to the load (35) to the load of the first power supply (30) (46c). 35) The power supply apparatus according to any one of (1) to (10), wherein the power supply is supplied in addition to the power supply to 35).

  (12) The power supply device according to (11), wherein the voltage-transforming regulator is a step-up regulator (40) (FIG. 6).

  (13) The power supply device according to (11), wherein the voltage-transforming regulator is a step-up / down regulator (40a) (FIG. 11).

  (14) The power supply device according to (11), wherein the voltage-transforming regulator is a step-down regulator (40b) (FIG. 12).

  (15) The power supply device according to (11) or (12), wherein the transformer regulator is a boost regulator (40).

  (16) The power supply device according to (11), wherein the transformer regulator is a forward regulator (40c) (FIG. 13).

  (17) The second power supply (26) includes an overvoltage detection means (51) for detecting an overvoltage in which the voltage at the constant current output terminal exceeds a set value, and stops the current output when the overvoltage is detected. The power supply device as described in any one of thru | or (16).

  (18) The power supply device is further supplied with a third power source (31) that is fed from a power feed line (27) that feeds power to the first power source (30) from the outside and feeds a load (36) that is separate from the load (35). The control means (20), when increasing the output power of the third power supply (31), the first power supply (30) supplies power to the load (35) via the upper limit instruction signal (MCD). The power supply device according to (10) above. According to this, the power consumption of the entire device can be kept below a certain level using the upper limit instruction signal (MCD).

  (19) The power source according to (18), wherein the control means (20) charges the power storage device (37) by the charging means (38) while the output power of the third power source (31) is small. apparatus.

  (20) When the input power supply voltage (storage voltage) used for the constant current output of the second power supply (26) is low, the control means (20) receives the first power supply (30) via the upper limit instruction signal (MCD). The power supply device according to (10), (18), or (19), wherein the current value supplied to the load (35) is increased.

(21) an image forming device (200) for forming an image on paper; and
The power supply device according to (9) or (10), which supplies power to an electrical load of the imaging device (200);
An image forming apparatus comprising:

  (22) The image forming device (200) forms an electrostatic latent image on the photosensitive member (201), develops the electrostatic latent image into a toner image, and directly or via the intermediate transfer member. Image forming means (201 to 210) for indirectly transferring to a paper, and a fixing device (214) including a fixing heater (36) for fixing the toner image on the paper to the paper; A third power source (31) that is fed from a power feed line (27) that feeds power to the first power source (30) from the outside and feeds power to the fixing heater (36); The two power sources (26) supply power to a power load other than the fixing heater; The image forming apparatus according to (21).

  (23) The control means (20) increases the power distribution of the power supply line (27) to the third power source (31) and raises the upper limit instruction signal when raising the fixing temperature of the fixing device (214). The image forming apparatus according to (22), wherein a current value supplied to the load (35) by the first power supply (30) via the (MCD) is reduced. Thereby, the power consumption of the whole apparatus can be kept below a certain level.

  (24) When the fixing temperature of the fixing device (214) is raised and the voltage of the power storage device (37) is low, the control means (20) is configured to supply the power supply line (27) to the third power source (31). The image forming apparatus according to (23), wherein the power distribution of the first power source (30) is increased by increasing the upper limit instruction signal (MCD) and increasing the current value supplied to the load (35). Thereby, the power consumption of the whole apparatus can be kept below a certain level.

  (25) The control means (20) turns off the third power source (31) when the standby mode in which image formation can be started in response to the image formation start instruction continues for a set time without any instruction input or operation by the user. The image forming apparatus according to any one of (22) to (24), wherein the first power supply (30) shifts to an energy saving mode for turning off a circuit unit that supplies power to a load required for image formation.

  (26) After the control means (20) shifts to the energy saving mode, the control means (20) turns on the third power source (31) in response to the user's instruction input or operation, and is necessary for image formation of the first power source (30). The image forming apparatus according to (25), wherein the image forming apparatus returns to the standby mode in which a circuit unit that supplies power to a load is turned on.

  (27) The control means (20) lowers the upper limit instruction signal (MCD) and raises the first power supply (30) when the fixing temperature of the fixing device (214) is raised immediately after shifting to the standby mode. After the current value supplied to the load (35) is reduced and the fixing temperature is raised, the upper limit instruction signal (MCD) is raised and the first power supply (30) supplies the load (35). The image forming apparatus according to (26), wherein the value is increased.

  (28) The control means (20) charges the power storage device (37) by the charging means (38) when power supply from the second power source (26) to the load is stopped in the standby mode. The image forming apparatus according to (27), which is performed.

  (29) A printer controller (501) for converting document information given from the outside into image data used for image formation of the image forming device (200); and an image represented by the image data in the image forming device (200) The image forming apparatus according to any one of (21) to (28), further comprising: an image forming control unit (510) formed in step (5).

  (30) The image forming apparatus according to any one of (21) to (29); an image reading apparatus (100) that generates image data representing an image projected by an optical system; and the image data An image data processing device (IPP) that converts the image signal into an image signal suitable for image formation by the image forming device and supplies the image signal to the image forming device;

  Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

  FIG. 1 shows the external appearance of a full-color digital multi-function copier MF1 according to the first embodiment of the present invention. The full-color copying machine MF1 is roughly constituted by units of an automatic document feeder (ADF) 120, an operation board 10, a color scanner 100, and a color printer 200. The operation board 10 and the color scanner 100 with the ADF 120 are units that can be separated from the printer 200, and the color scanner 100 includes a control board having a power device driver, sensor input, and controller. It communicates directly or indirectly with the engine controller to read the document image under timing control.

  FIG. 2 shows the mechanism of the color printer 200 of the multi-function copying machine MF1. The color printer 200 of this embodiment is a laser printer. The laser printer 200 includes four toner image forming units a to d for forming images of each color of magenta (M), cyan (C), yellow (Y), and black (black: K). They are arranged in this order along the moving direction of the transfer belt 208 (from left to right y in the figure). That is, it is a four-drum type (tandem type) full-color image forming apparatus. A neutralizing device, a cleaning device, a charging device 202 and a developing device 204 are arranged on the outer periphery of the photosensitive member 201 that is rotatably supported and rotates in the direction of the arrow. A space for storing optical information emitted from the exposure device 203 is secured between the charging device 202 and the developing device 204. There are four (a, b, c, d) photoconductors 201, but the image forming component configuration provided around each is the same. The color of the color material (toner) handled by the developing device 204 is different. A part of each photoconductor 201 (four) is in contact with the first transfer belt 208. A belt-like photoreceptor can also be employed.

  The first transfer belt 208 is supported and stretched between a rotating support roller and a driving roller so as to be movable in the direction of the arrow. The first transfer roller is located near the photoconductor 201 on the back side (inside the loop). Has been deployed. A cleaning device for the first transfer belt is disposed outside the belt loop. After the toner image is transferred from the first transfer belt 208 to the transfer paper (paper) or the second transfer belt 215, unnecessary toner remaining on the surface is wiped off. The exposure device 203 uses a known laser system to form an electrostatic latent image by irradiating the uniformly charged photoconductor surface with optical information corresponding to full-color image formation. An exposure apparatus comprising an LED array and an image forming means can also be employed.

  In FIG. 2, a second transfer belt 215 is disposed on the right side of the first transfer belt 208. The first transfer belt 208 and the second transfer belt 215 come into contact with each other to form a predetermined transfer nip. The second transfer belt 215 is supported and stretched between a support roller and a drive roller so as to be movable in the direction of the arrow, and a second transfer means is provided on the back side (inside the loop). A cleaning device, a charger, and the like for the second transfer belt are provided outside the belt loop. After the toner is transferred to the paper, the cleaning device wipes off the remaining unnecessary toner. The transfer paper (paper) is stored in the paper feed cassettes 209 and 210 in the lower part of the figure, and the uppermost paper is conveyed one by one by the paper feed roller to the registration roller 233 through a plurality of paper guides. Above the second transfer belt 215, a fixing device 214, a paper discharge guide 224, a paper discharge roller 225, and a paper discharge stack 226 are arranged. A storage unit 227 for storing replenishment toner is provided above the first transfer belt 208 and below the paper discharge stack 226. The toner has four colors, magenta, cyan, yellow, and black, and is in the form of a cartridge. The developing device 204 of the corresponding color is appropriately supplied by a powder pump or the like.

  Here, the operation of each unit during duplex printing will be described. First, image formation by the photoconductor 201 is performed. That is, by the operation of the exposure device 203, light from an LD light source (not shown) passes through an optical component (not shown), and among the photoconductors 201 uniformly charged by the charging device 202, the photoconductor of the image forming unit a. Then, a latent image corresponding to the writing information (information corresponding to the color) is formed. The latent image on the photoconductor 201 is developed by the developing device 204, and a visible image with toner is formed and held on the surface of the photoconductor 201. This toner image is transferred onto the surface of the first transfer belt 208 that moves in synchronization with the photoreceptor 201 by the first transfer means. The surface of the photoconductor 201 is cleaned by the cleaning device with the remaining toner, and is neutralized by the static eliminator to prepare for the next image forming cycle. The first transfer belt 208 carries the toner image transferred on the surface and moves in the direction of the arrow. A latent image corresponding to another color is written on the photoconductor 201 of the image forming unit b, and developed with a toner of the corresponding color to become a visible image. This image is overlaid on the visible image of the previous color already on the first transfer belt 208, and finally four colors are overlaid. In some cases, only monochrome black is formed. At this time, the second transfer belt 215 is moved in the direction of the arrow in synchronization, and the image formed on the surface of the first transfer belt 208 is transferred to the surface of the second transfer belt 215 by the action of the second transfer means 117. The The first and second transfer belts 208 and 215 are moved while the images are formed on the respective photosensitive members 201 of the four image forming units a to d in the so-called tandem format. Can be shortened. When the first transfer belt 208 moves to a predetermined position, a toner image to be created on another side of the paper is formed again by the photoconductor 201 in the process described above, and paper feeding is started. The uppermost sheet in the sheet feeding cassette 121 or 122 is pulled out and conveyed to the registration roller 233. The toner image on the surface of the first transfer belt 208 is transferred by the second transfer unit 117 to one side of the sheet fed between the first transfer belt 208 and the second transfer belt 215 via the registration roller 233. Further, the recording medium is conveyed upward, and the toner image on the surface of the second transfer belt 215 is transferred to the other surface of the sheet by the charger. At the time of transfer, the sheet is conveyed at a timing so that the position of the image is normal.

  The paper on which the toner images are transferred on both sides in the above steps is sent to the fixing device 214, and the toner images (both sides) on the paper are melted and fixed at one time. Are discharged to the paper discharge stack 226. As shown in FIG. 2, when the paper discharge units 224 to 226 are configured, the side (page) of the double-sided image that is later transferred to the paper, that is, the surface that is directly transferred from the first transfer belt 208 to the paper is the lower surface. Since the image is placed on the paper discharge stack 226, an image of the second page is created first and the toner image is held on the second transfer belt 215 in order to align the pages. The image is directly transferred from the first transfer belt 208 to the sheet. The image directly transferred from the first transfer belt 208 to the paper is a normal image on the surface of the photoconductor, and the toner image transferred from the second transfer belt 215 to the paper is a reverse image (mirror image) on the surface of the photoconductor. It is exposed as follows. Such image forming order for page alignment and image processing for switching between normal and reverse images (mirror images) are also performed by image data read / write control on the memory on the controller 501. After transfer from the second transfer belt 215 to the paper, a cleaning device including a brush roller, a collection roller, a blade, and the like removes unnecessary toner and paper dust remaining on the second transfer belt 215.

  In FIG. 2, the brush roller of the cleaning device for the second transfer belt 215 is in a state separated from the surface of the second transfer belt 215. The structure can swing around a fulcrum and can be brought into contact with and separated from the surface of the second transfer belt 215. Before the transfer onto the paper, the second transfer belt 215 is separated when carrying a toner image, and when cleaning is required, it is swung in the counterclockwise direction in FIG. The removed unnecessary toner is collected in a toner storage unit. The image forming process in the duplex printing mode in which the “duplex transfer mode” is set has been described above. In the case of duplex printing, printing is always performed by this image forming process.

  In the case of single-sided printing, there are two types of "single-sided transfer mode by the second transfer belt 215" and "single-sided transfer mode by the first transfer belt 208", and the single-sided transfer mode using the former second transfer belt 215 is set. In this case, a visible image formed in three colors, four colors, or monochromatic black on the first transfer belt 208 is transferred to the second transfer belt 215 and transferred to one side of the paper. There is no image transfer on the other side of the paper. In this case, there is a print screen on the upper surface of the printed paper discharged to the paper discharge stack 226. When the single-sided transfer mode using the latter first transfer belt 208 is set, a visible image formed in three colors, four colors, or single color black is transferred to the second transfer belt 215 on the first transfer belt 208. Instead, it is transferred to one side of the paper. There is no image transfer on the other side of the paper. In this case, there is a print screen on the lower surface of the printed paper discharged to the paper discharge stack 226.

  FIG. 3 shows the system configuration of the electrical system of the multifunction copying machine MF1 shown in FIG. The electrical system communicates with the outside using a printer controller 501 that performs overall control of the image forming apparatus, an operation board 10 of the image forming apparatus connected to the controller 501, an HDD 503 that stores image data, and an analog line. Communication control device interface board 504, LAN interface board 505, FAX control unit 506, IEEE1394 board, wireless LAN board, USB board, etc. 507 connected to general-purpose PIC bus, and engine control 510 connected to the controller via PCI bus The input / output control 20 that controls the I / O of the image forming apparatus connected to the engine control 510, the scanner board (SBU: Sensor Board Unit) 111 that reads the copy original (image), and the image data are represented. Image light Projected on the photosensitive drum (light writing) constituted by the optical writing unit 512 and the like.

  A scanner 100 that optically reads an original scans the original with an original illumination light source, and forms an original image on the CCD 110. An original image, that is, reflected light of light irradiation on the original is photoelectrically converted by the CCD 110 to generate R, G, B image signals.

  The communication control device interface board 504 immediately informs an external remote diagnosis device when a failure occurs in the device, and allows the service person to recognize the contents and situation of the failure part and repair them immediately. . In addition, it is also used for sending out the usage status of the device.

  The CCD 110 shown in FIG. 3 is a three-line color CCD, which generates R, G, and B image signals of EVENch (even-numbered pixel channel) / ODDch (odd-numbered pixel channel), and outputs it to an analog ASIC (Application Specific IC) on the SBU board. input. The SBU board 111 includes an analog ASIC and a circuit for generating drive timings for the CCD and analog ASIC. The output of the CCD 110 is sampled and held by a sample and hold circuit inside the analog ASIC, then A / D converted, converted into R, G and B image data, and shading corrected, and an output I / F (interface) At 112, the data is sent to an image data processor IPP (Image Processing Processor; hereinafter simply referred to as IPP) via an image data bus.

  IPP is a programmable arithmetic processing means that performs image processing, separation generation (determination of whether an image is a character area or a photographic area: image area separation), background removal, scanner gamma conversion, filter, color correction, scaling, and image processing. , Perform printer gamma conversion and gradation processing. The image data transferred from the SBU to the IPP is corrected by the IPP for signal deterioration due to quantization of the optical system and the digital signal (signal deterioration of the scanner system) and written in the frame memory 521.

  The printer controller 501 includes a ROM that controls the CPU and the printer controller board, a RAM that is a working memory used by the CPU, a lithium battery, an NV-RAM that includes an SRAM backup and a clock, and a printer controller board. The system bus control, frame memory control, FIFO, and other ASICs for controlling the CPU periphery and their interface circuits are mounted.

  The printer controller 501 has functions of a plurality of applications such as a scanner application, a facsimile application, a printer application, and a copy application, and controls the entire system. The input of the operation board 10 is decoded, and the setting of the system and the state contents are displayed on the display unit of the operation board.

  Many units are connected to the PCI bus, and image data and control commands are transferred in a time division manner by the image data bus / control command bus.

  The communication control device interface board 504 is a communication interface board between the communication control device and the controller 501. Communication with the controller 501 is connected by full-duplex asynchronous serial communication. The communication control device 522 is multi-drop connected according to the RS-485 interface standard. Communication with the remote management system is performed via the communication controller device interface board 504.

  The LAN interface board 505 is connected to an in-house LAN. It is a communication interface board between the in-house LAN and the controller 501, and is equipped with a PHY chip. The LAN interface board 505 and the controller 501 are connected by standard communication interfaces of a PHY chip I / F and an I2C bus I / F. Communication with an external device is performed via the LAN interface board 505.

  The HDD 503 is used as an application database that stores system application programs and device activation information of printers and image forming process devices, and an image database that stores image data of read images and written images, that is, image data and document data. . Both the physical interface and the electrical interface are connected to the controller through an interface compliant with ATA / ATAPI-4.

  In addition to the liquid crystal touch panel, the operation board 10 includes a numeric keypad, a clear / stop key, a start key, an initial setting key, a mode switching key, a test print key, a power key, and the like. On the left side of the liquid crystal touch panel, there is an alphabet keyboard with hiragana added for inputting, setting, and abbreviated registration for URL, mail text, file name, folder name, and the like.

  On the liquid crystal touch panel, various function keys and messages indicating the operation states of the engine 510 and the controller 501 are displayed. The LCD touch panel has functions for selecting and executing the “Copy” function, “Scanner” function, “Print” function, “Facsimile” function, “Store” function, “Edit” function, “Register” function and other functions. A function selection key is displayed. An input / output screen determined for the function specified by the function selection key is displayed. For example, when the “copy” function is specified, a message indicating the function key, the number of copies, and the state of the image forming apparatus is displayed. When the operator touches a key displayed on the liquid crystal touch panel, the operation board 10 reads it as an operator input, and highlights the key indicating the selected function in gray indicating designation. Further, when it is necessary to specify the details of a function (for example, the type of page printing), a detailed function setting screen is popped up by touching a key. Thus, since the liquid crystal touch panel uses a dot display device, it is possible to graphically perform an optimal display at that time. Among the function keys, print color designation keys “black (Bk)”, “full color”, “automatic color selection”, “blue (C)”, “red (M)” and “yellow (Y)” designation keys There is.

  Inside the operation board 10, a CPU, ROM, RAM, LCD, and ASIC (LCDC) for controlling key input are mounted. In the ROM, a control program for the operation board 10 that controls input reading and display output of the operation board 10 is written. The RAM is a working memory used by the CPU. Through communication with the printer controller 501, the panel is operated to perform input for the user to input system settings, and display and input control for displaying the setting contents and status of the system to the user.

  The Bk, C, M, and Y writing signals (image DATA) output from the work memory of the printer controller 501 are input to the optical writing unit 512. The optical writing unit 512 performs LD current control (PWM control) based on the write signal, and each LD is energized (driven; energized) in response to the write signal.

  The engine control 510 mainly performs image formation control, that is, image formation control, and includes a CPU, an IPP that performs image processing, a ROM that contains programs necessary to control copying and printout, a RAM that is necessary for the control, and NV-RAM is installed. The NV-RAM is equipped with an SRAM and a memory that detects power-off and stores it in the EEPROM. The I / O ASIC that also has a serial interface that transmits and receives signals to and from other CPUs that perform control is a nearby I / O (counter, fan, solenoid, motor, etc.) on which an engine control board is mounted. ASIC for controlling the). The input / output control 20 and the engine control board 510 are connected via a synchronous serial interface.

  The input / output control 20 is equipped with a sub CPU, and performs I / O control of the image forming apparatus including analog control such as P sensor and T sensor, jam detection referring to a detection signal of the paper sensor, and paper transport control. Power supply control is performed. The input / output control 20 has interface circuits with various sensors and actuators (motors, clutches, solenoids).

  The power supply device includes a main power supply 29 to which an external input AC is applied via a main power switch 28, an auxiliary power supply 32, a load current detector 33 for detecting a current value supplied to a 24V system load of the copying machine MF1, and a current indicator. There are 64.

  FIG. 4 shows the configuration of the power supply device in some detail. When the main power supply SW 28 is turned on (closed), commercial AC power is supplied to the main power supply 29 and the auxiliary power supply 32. The commercial AC voltage is applied from the commercial AC power source to the fixing power source 31 and the constant voltage power source 30 which are AC control circuits of the main power source 29 and the capacitor charger 38 of the auxiliary power source 32. The fixing power source 31 sets the fixing device temperature by the heat generation of the fixing heater 36 of the fixing device 214 (FIG. 2) within the phase angle limit corresponding to the high, medium, and low power instruction signals given from the input / output control 20 as a target value. The power supply thyristor is triggered to conduct at a thyristor conduction phase angle to match (reload target value / standby target value / image formation target value), and AC power is supplied to the fixing heater 36. That is, the fixing device temperature is feedback controlled within the power range specified by the high, medium, and low power instruction signals.

  A constant voltage power supply 30 as a first power supply of the main power supply 29 converts commercial AC into DC and generates two DC constant voltages of 5V and 24V by constant voltage feedback control of the DC / DC converter to generate 5V Output to system load and 24V system load. The CPU of each control unit operates using a 5V constant voltage generated by the constant voltage power supply 30. The 24V output of the main power supply 29 is applied to the 24V system load 35.

  In the present embodiment, the auxiliary power source 32 is a constant current power source which is a second power source that outputs a constant current to the capacitor charger 38, the capacitor 37 charged thereby, and the capacitor power to the power supply line to the 24V system load 35. 26. The load current detector 33 detects a 24V system load current value, which is the sum of the current values simultaneously supplied by the constant voltage power supply 30 (first power supply) and the constant current power supply 26 (second power supply), and outputs a current detection signal, The current indicator 64 is given. The input / output control 20 provides the current indicator 64 with upper limit instruction data MCD that specifies the output current upper limit value of the constant voltage power supply 30. The current indicator 64 provides the constant current power supply 26 with a current instruction signal indicating a value obtained by subtracting the upper limit instruction value from the 24V system load current value (= output current instruction value of the constant current power supply 26). The constant current power supply 26 supplies the electric power of the capacitor 37 to the 24V system load line with constant current by constant current control using the current value indicated by the current instruction signal as a target value.

  When the main power SW 28 is switched from OFF to ON, commercial AC is supplied to the fixing power source 31, the constant voltage power source 30 and the capacitor charger 38, the fixing power source 31 supplies power to the fixing heater 36, and the constant voltage power source 30 is 5V. And 24V constant voltage is generated. At this time, if the fixing device temperature is low, the input / output control 20 increases the power consumption allocation to the fixing power source 31 and heats up (reloads) the fixing device 214. In this state, power consumption by the fixing heater 36 is large. The standby mode is a state in which the fixing device 214 finishes heating up and waits for a print instruction. In this state, the power consumption of the copying machine is small. When there is a standby mode copy or print instruction, the printer controller 501 instructs the engine control 510 to copy or print, and the engine control 510 starts this. The state in which the engine control 510 is executing copying or printing is an operation mode, and power consumption is large. The input / output control 20 performs input / output with respect to the sensor and various loads in accordance with the input / output control command of the engine control 510.

  The capacitor 37 of the auxiliary power supply 32 is composed of a large capacity capacitor such as an electric double layer capacitor. In addition to the electric double layer capacitor, various selections can be made. In this embodiment, an electric double layer capacitor that can be charged and discharged in a short time and has a long life is used. A characteristic of the electric double layer capacitor is that the terminal voltage (capacitor voltage) becomes lower as it is discharged. Therefore, by arranging the constant current power source 26 after the capacitor 37, the required current value is obtained regardless of the fluctuation of the capacitor voltage. Is output.

  FIG. 5 is a block diagram showing the configuration of the input / output control 20. The input / output control 20 is a CPU 21 that performs input / output control for the sensor and load and control of the power supply device in accordance with a control command from the engine control 510, a program stored in the ROM 22, and a program and data stored in the nonvolatile RAM 24. , ROM 22 for storing a program for operating the CPU 21, RAM 23 used as a work memory for the CPU 21, a power consumption table storing power consumption data in each load operation state and each operation mode, and printing in each operation mode Non-volatile RAM 24 for storing a print processing time table storing time data required for processing, input reading of each sensor 26 of full-color digital multi-function copier MF1, and individual driving (energization / deactivation) of load 35 I / O control unit 25 to control It is equipped with a.

  The input / output control 20 performs input / output control and power supply control to the sensor and load in accordance with instructions accompanying process control and sequence control such as image reading, printing, copying, etc. of the engine control 510. In response, each load is operated sequentially. The input / output control 20 also controls the charging / discharging of the capacitor 37. The 24V system load 35 is obtained from the electric power stored in the capacitor 37 during the start-up of the device and for a predetermined time after the start-up. Power to At this time, the amount of power supplied to the fixing heater 36 is increased by the margin generated with respect to the power supplied from the AC line 27. In the standby mode in which the fixing power is low and the load current is small, the capacitor 37 is charged using the charger 38.

  FIG. 6 shows the configuration of the constant current power supply 26, the load current detector 33, and the current indicator 64 shown in FIG. The capacitor 37 is an electric double layer capacitor in this embodiment. The electric double layer capacitor has a low withstand voltage, and the charging upper limit voltage in use is 2.5V. Therefore, in order to obtain a high voltage, it is necessary to connect many in series. However, the same capacity can be obtained at a lower cost by using a small number of large-capacitance capacitors rather than connecting many small-capacitance capacitors in series. In order to supply power to a 24V load, when an electric double layer capacitor is used in a series of 9 or less, the charging upper limit voltage is 22.5V or less, so it is necessary to configure the constant current power supply 26 using a boost regulator. is there. Thus, in this embodiment, the boost regulator 40 boosts the power of the capacitor 37 and outputs a constant current.

  The semiconductor switch 41 of the boost regulator 40 is turned on (ON) during the H period of the output PWM pulse of the PWM controller 42, and is turned off (OFF; off) during the L period. When the switch 41 is turned on, a current flows from the capacitor 37 to the reactor 43 and the switch 41, and the reactor 43 stores power. When the switch 41 is turned off, the stored power of the reactor 43 becomes high and the capacitor 44 passes through the diode 44. 45 is charged with high voltage. By repeating ON / OFF of the PWM pulse cycle of the switch 41, the voltage of the capacitor 45 rises, passes through the current detection resistor 47, through the semiconductor switch 56 of the power supply ON / OFF controller 55, and further to the current of the load current detector 33. Power is supplied to the 24V system load 35 through the detection resistor 60.

  The load current detector 33 amplifies the potential difference between both ends of the current detection resistor 60 by the differential amplifier 61, and generates a load current signal (voltage drop voltage of the resistor 60: (a) in FIG. 7) proportional to the load current value. It is generated and output (applied) to the current indicator 64 through a low-pass filter composed of a resistor 62 and a capacitor 63. The low-pass filter has a time constant of about several tens of msec that absorbs and smoothes overcurrent (rush current) for a period of about 10 msec when the motor is started.

  The current indicator 64 analog-converts the current upper limit value instruction data MCD provided by the input / output control 20 into an upper limit instruction signal (voltage) by the D / A converter 65, and the differential amplifier 66 performs load current detection value−upper limit instruction value. The negative voltage is cut off by the diode 67 and output to the constant current power supply 26 as a current instruction signal. That is, the current indicator 64 determines the upper limit of the AC power consumption allocation to the output current of the constant voltage power supply 30 indicated by the input / output control 20 from the detected 24V load current value (required load current value). The difference value ((b) in FIG. 7) obtained by subtracting (value) is set as a target current value to be borne by the constant current power supply 26, and the corresponding current output is instructed to the constant current power supply 26.

  The constant current power supply 26 amplifies the potential difference between both ends of the current detection resistor 47 with a differential amplifier 48, and generates an output current signal (voltage drop voltage of the resistor 47) proportional to the output current value. The bias circuit 49 supplies the differential amplifier 50 with a positive bias output current signal obtained by raising the voltage level of the output current signal by a set value. The differential amplifier 50 provides the PWM controller 42 with a difference between the target current value provided by the current indicator 64, that is, an error voltage of constant current feedback control, as a duty indication signal of the PWM pulse from the positive bias output current signal.

  The PWM controller 42 determines the duty of the PWM pulse for driving the semiconductor switch 41 on / off to the duty specified by the duty instruction signal. That is, when the output signal of the current indicator 64 (target current value to be borne by the constant current power supply 26) increases and the output voltage of the differential amplifier 50 decreases, the duty of the PWM pulse is increased. As a result, the output current value of the boost regulator 40 increases. As a result, when the voltage drop of the current detection resistor 47 increases and the level of the output current detection signal rises and the output voltage of the differential amplifier 50 rises, the duty of the PWM pulse is lowered. As a result, the output current value of the boost regulator 40 decreases. By such feedback PWM control, the output current value of the boost regulator 40 is determined by the input / output control 20 from the 24V load current detection value (required load current value) given by the current indicator 64. This is a value corresponding to the difference obtained by subtracting the output current upper limit value MCD. FIG. 7C shows a 24V system load current detection value (solid line), an output current upper limit value (indicated value) MCD (dotted line) of the constant voltage power supply 30, and an output current value of the constant current power supply 26 (dashed line). The relationship between the three is shown.

  In addition to the load that the input / output control 20 controls on / off, the 24V system load 35 includes a 24V system load such as a cooling fan that is always driven in the standby mode and the operation mode. Even if the target 24V system load is turned off (non-energized), the load current flows through the power supply line (load current detector 33) to the 24V system load. Since the boost regulator 40 shown in FIG. 6 is a boost type boost type, even if the PWM controller 42 stops the switching operation (PWM pulse output) of the semiconductor switch 41, the output voltage of the regulator 40 is input. When the voltage drops below the voltage, current flows from the input to the output. That is, the capacitor 37 is discharged. If the main power switch 28 is turned off, the 24V output voltage of the constant voltage power supply 30 disappears, and if any of the 24V loads is turned on, the capacitor 37 is discharged to the load. In order to prevent this, in this embodiment, the constant current power supply 26 is provided with a power supply ON / OFF controller 55.

  The power supply ON / OFF controller 55 monitors the voltage at the output terminal of the power supply 26 with the voltage detector 57, and subtracts the drop voltage due to the load current from the lower limit value of the 24V output voltage of the constant voltage power supply 30. When a set value (for example, 22.8 V) or less, which is slightly smaller than the value, the monitoring output signal is switched from a normal high level H to a low level L indicating an output low voltage abnormality. Since the input / output control 20 provides the AND gate 58 with the power ON / OFF instruction signal (H: ON instruction / L: OFF instruction), the monitoring output signal of the voltage detector 57 is H indicating normality. Although the output of the AND gate 58 is H and the transistor 59 is ON and the semiconductor switch 56 is ON, when the monitoring output signal of the voltage detector 57 switches to L indicating a low voltage abnormality, the transistor 59 turns OFF. As a result, the semiconductor switch 56 turns OFF, and the output of the power supply 26 to the load power supply line is shut off. That is, the capacitor 37 is prevented from being discharged. The output signal of the AND gate 58 (H: current output instruction / L: current output cutoff instruction) is also given to the PWM controller 42. In response to this signal, the PWM controller 42 is H (current output instruction). The aforementioned PWM pulse is applied to the semiconductor switch 41 to drive it ON / OFF. If it is L (current output cutoff instruction), L is applied to the semiconductor switch 41 to constrain the semiconductor switch 41 to OFF. This OFF prevents the capacitor 37 from passing through the semiconductor switch 41 from being discharged.

  When the voltage at the output terminal of the constant current power supply 26 exceeds a threshold value (set value) set using the constant voltage element 52, the voltage limiter 51 changes the output of the comparator 53 from L representing normal to H representing abnormal. Switch to. This H raises the PWM control signal to the PWM 42 through the diode 54 to a voltage level that designates a duty of 0 or less, and restrains the semiconductor switch 41 to be continuously OFF. If the voltage at the output terminal of the constant current power supply 26 becomes abnormally high, the output current value detected by the resistor 47 is thereby lowered, and the PWM controller 42 increases the output current value in response to this. Since the duty is increased, the high abnormality of the output voltage is further amplified. The voltage limiter 51 prevents such abnormal operation. The set value for stopping the operation of the regulator 40 of the voltage limiter 51 needs to be higher than the maximum value of the normal output voltage of the constant voltage power supply 30. Since the normal range of the output voltage of the constant voltage power supply 30 is set to 24V + 5% or less and −4% or more, it needs to be 25.2V or more. On the other hand, the upper limit of the output voltage to the load 35 is 24V + 10%, so it is necessary to be 26.4V or less. Therefore, in this embodiment, the set value (limit voltage) of the voltage limiter 51 is set to a value within the range of 25.2V or more and 26.4V or less.

  Next, an outline of the transition of the output current of the constant current power supply 26 will be described. In the fixing reload period in which the fixing temperature is raised to the target temperature immediately after the main power switch 28 is turned on, in order to satisfy the starting time required for the apparatus, a larger amount of electric power than usual is supplied to the fixing heater 36, and the fixing heater 36 36 is brought up as soon as possible to a temperature at which printing is possible. Raising the fixing temperature to a temperature at which printing is possible is called fixing reload. At this time, power is supplied simultaneously to both the constant voltage power supply 30 and the constant current power supply 26 to the + 24V system load 35 to reduce the AC power consumption of the constant voltage power supply 30 and increase the AC power allocation of the fixing power supply 31. Increase the fixing heater current and shorten the startup time.

  Further, once the fixing heater 36 reaches a temperature at which printing can be performed, the printing operation is started after the completion of the fixing reload even though the fixing heater supply power may be smaller than that at the time of startup in order to maintain the temperature. In some cases, the power consumption of the load 35 increases due to the start of the motor or the like, and the total power including the fixing heater supply power may exceed the power that can be supplied from the AC power supply line 27. In order to make the supplied power equal to or lower than the supplyable power ((a) of FIG. 8), the power distribution of the fixing power supply 31 is lowered ((b) of FIG. 8), the AC power consumption of the fixing power supply 31 and the constant voltage power supply 30 The output power of the constant voltage power supply 30 is increased to the maximum value that limits the AC power consumption within the maximum power of the AC power supply line ((c) of FIG. 8). That is, the current upper limit value MCD that the input / output control 20 gives to the current indicator 64 is set to a value capable of the output power ((d) and (e) in FIG. 8). That is, the AC power consumption is suppressed to be equal to or lower than the maximum power that can be supplied from the power line 27. As a result, the constant current power supply 26 supplies the load 35 with an insufficient load current ((f) in FIG. 8) that is not sufficient for the output current value of the constant voltage power supply 30 for suppressing the AC power consumption near the upper limit value. To do.

  The current upper limit value MCD (digital data in this embodiment) given to the current indicator 64 by the input / output control 20 variably sets the upper limit value of the output power of the constant voltage power supply 30, and determines the sharing timing and power of the constant current power supply 26. Variable adjustment is performed.

  In FIG. 9, immediately after the operation voltage required for printing and copying is applied to each part of the copying machine MF1 by switching the main power switch 28 from OFF to ON or returning from the energy saving mode to the standby mode. An outline of “power feeding control” PSCa started by the input / output control 20 (CPU 21 thereof) is shown. When a standby mode in which a required operating voltage is applied to each part of the copying machine MF1 is entered, the input / output control 20 reads the fixing device temperature from the fixing power source 31, and then the voltage detection circuit 39 detects the voltage of the capacitor 37. The switch connected to the end is turned on, the level of the voltage detection signal of the voltage detection circuit 39 is A / D converted and read, and the switch is turned off (step 1). That is, during a period when it is not necessary to grasp the capacitor voltage, the voltage detection circuit 39 is cut off from the voltage detection terminal of the capacitor 37 to prevent the capacitor 37 from being discharged by the voltage detection circuit 39.

  In the following, the word “step” is omitted from the parentheses, and step no. Write only the symbol.

  Next, the input / output control 20 determines the fixing power HRP (upper limit value of fixing power consumption) for the fixing power source 31 and the current upper limit value MCD of the constant voltage power source 30 by “power supply setting in standby mode (Table 1)”. The fixing power HRP instruction signal is supplied to the fixing power source 31, and the current upper limit value MCD data is supplied to the current indicator 64 (2). Then, the power ON / OFF instruction signal to the constant current power supply 26 is switched to H which indicates “ON” (3). The fixing power source 31 starts temperature feedback control for setting the fixing device temperature to the target temperature at that time within the range of the instructed fixing power HRP, and the constant current power source 26 exceeds the current upper limit value MCD. Start the current output sharing the load current of the minute.

  In this embodiment, the fixing power instruction value HRP has three values, a high value HRPt1, an intermediate value HRPt2, and a low value HRPt3, as shown in FIG. The current upper limit value MCD also has three values: a high value MCDt3, an intermediate value MCDt2, and a low value MCDt1. As shown in FIG. 10, the combination of the fixing power instruction value HRP and the current upper limit value MCD is changed as the image forming sequence proceeds, and a part of the required power at the time of high load is shared by the auxiliary power source 32. As a result, the AC power consumption is always kept within the allowable upper limit value of the AC power supply line 27, and the entire copying machine executes a high-power image forming process with power consumption exceeding the allowable upper limit value in a short time. Can do.

  The values of the fixing power HRP and the current upper limit value MCD are stored in the nonvolatile RAM 24 of the input / output control 20 divided into two groups (tables) according to the main mode (standby mode / operation mode) of the copying machine MF1. Yes. Table 1 shows values of the fixing power HRP and the current upper limit value MCD assigned to the “standby mode”. That is, Table 1 is a power distribution table in the standby mode. Table 2 shows those assigned to the “operation mode”. Table 2 is an operation mode power distribution table.

  The fixing power HRP and the current upper limit value MCD in the power distribution table (Table 1) in the standby mode are the voltage Cv of the capacitor 37 of the auxiliary power supply 32 (corresponding to the available remaining power) and whether or not the fixing reload is required (the fixing temperature is rapidly changed). Necessity of start-up) is defined as a parameter. Specifically, since the auxiliary power supply 32 has a power supply capability when the capacitor voltage Cv is high, the current upper limit value MCD is a low value (MCDt1) where the possibility of power supply from the auxiliary power supply 32 and the output current value at the time of power supply increase. When the capacitor voltage Cv is low, it is set to a high value (MCDt3). Note that the load current is not constant when viewed in detail, and is a combination of short cycle fluctuations. Since the load current detection signal of the load current detector 33 shown in FIG. 6 smoothes the instantaneous fluctuation of the load current by the low-pass filters 62 and 63, the constant voltage power supply 30 outputs the current at the smoothed level. Supply power to the load. Then, when the current upper limit value MCD is a set value lower than the fluctuation, the power supply from the constant voltage power supply 30 to the load 35 is substantially stopped during the load current period for the fluctuation. In order to avoid this, the current upper limit value MCD is always set to be higher than the fluctuation amount. That is, the minimum value MCDt1 of the current upper limit value MCD is a value higher than the amplitude of the load fluctuation in a short cycle.

  When the capacitor voltage Cv is equal to or lower than the discharge prohibition threshold Vcs, the current upper limit value MCD is the maximum value (MCDt3) that prohibits power supply from the auxiliary power supply 32 (capacitor 37), that is, the maximum value that the constant voltage power supply 30 bears all of the load. It is stipulated in. Since the voltage at the output terminal of the constant current power supply 26 (output voltage of the power supply 26: secondary side voltage) is approximately 24V constant, the capacitor voltage Cv (input voltage of the power supply 26: primary side voltage) decreases as the capacitor voltage Cv decreases. The input side current value (primary side current value) of the power source 26 for the current power source 26 to output the same current value increases. The boost regulator 40 that can withstand an excessive input side current value is expensive, and a practical boost regulator that can withstand an excessive input side current value cannot be realized. Therefore, from an economical point of view, in this embodiment, the discharge prohibition threshold (discharge stop voltage) Vcs is set to 50% of the full charge voltage of the capacitor 37.

  The fixing power HRP is set to a high value when fixing reloading is required, and is set to a low value when fixing reloading is not required. Since the image forming process is not executed in the standby mode that does not require fixing reload, the power consumption of the load 35 is small. At the time of fixing reload immediately before switching from the standby mode to the operation mode (when the fixing device temperature is rapidly raised), the power consumption of the load 35 increases to an intermediate level. A large amount of power can be allocated to the fixing power by increasing the power supply from.

  The fixing power HRP and the current upper limit value MCD in the power distribution table (Table 2) in the operation mode are determined by the voltage Cv of the capacitor 37 of the auxiliary power supply 32 (corresponding to the available remaining power) and the amount of heat required for fixing after the fixing reload is completed. It is determined as a parameter whether it is large or medium.

  Refer to FIG. 9 again. In the “standby mode power supply setting (Table 1)” in step 2 described above, whether or not fixing reload is necessary is determined based on the fixing device temperature at that time, and the capacitor voltage Cv at that time is high (discharge prohibition threshold). It is determined whether it is higher than Vcs) or lower (lower than the discharge prohibition threshold), and the fixing power HRP and the current upper limit MCD corresponding to the determination result are read from the power distribution table (Table 1: nonvolatile RAM 24) in the standby mode, A control signal designating the read fixing power HRP is given to the fixing power source 31, and the read current upper limit value MCD is given to the D / A converter 65 of the current indicator 64. In the next step 3, the input / output control 20 switches the power ON / OFF instruction signal to the constant current power supply 26 to “ON” instruction H, whereby the boost regulator 40 starts the DC / DC converter operation.

  When the fixing device temperature reaches the fixing reload target temperature, the input / output control 20 determines whether there is an image processing instruction from the operator (4, 5).

  When there is an image processing instruction, “operation mode power supply setting (Table 2)” (6) is executed. That is, first, the fixing power HRP and the current upper limit value MCD corresponding to the capacitor voltage Cv in the column of “large amount of heat required for fixing” on the power distribution table (Table 2: nonvolatile RAM 24) in the operation mode are read and fixed. The power supply 31 and the current indicator 64 are supplied. If the operation mode continues, the fixing device 214 is sufficiently warmed, so that HRP and MCD are read from the column “in the amount of heat required for fixing” in Table 2 and supplied to the fixing power source 31 and the current indicator 64.

  When the image processing ends, the input / output control 20 determines the fixing power HRP and the current upper limit value MCD corresponding to the capacitor voltage Cv at that time in the column of the power distribution table (Table 1) “fixing reload unnecessary” in the standby mode. The data is read out and given to the fixing power source 31 and the current indicator 64 (8), and an image processing instruction is awaited (9).

  Thereafter, when there is an image processing instruction, the fixing power HRP and the current upper limit value MCD are read and the update output to the fixing power source 31 and the current indicator 64 described in connection with the above steps 2 to 7 is performed (10 to 10). 14).

  When there is no image processing operation and the image processing instruction is awaited, the capacitor voltage Cv is read to search whether charging is necessary (15), and if charging is necessary, the capacitor 37 is charged using the charger 38 (16). . When there is no image processing operation and the image processing instruction wait (standby mode) continues for a set time (17), if the capacitor 37 does not need to be charged at this time, the power supplied to the power ON / OFF controller 55 of the constant current power supply 26 After the ON / OFF instruction signal is switched to L for instructing “OFF” (18), the mode shifts to the energy saving mode (19). If the capacitor 37 is being charged when the standby mode continues for the set time, the charging mode is completed and the energy saving mode is entered. When shifting to the energy saving mode, the input / output control 20 turns off the fixing power supply 31 and turns off the circuit portion of the constant voltage power supply 30 that supplies power to a load required for image formation. In this energy saving mode, the input / output control 20 is in a sleep state, and a user access monitoring circuit that is powered by a part of the constant voltage power supply 30 that is turned on even in the energy saving mode detects a user access and waits. The sleep state is continued until a steady operation voltage for waiting for an image processing instruction is applied to each unit by turning on the power to enter the mode. When a transition is made to the standby mode, that is, when a steady operating voltage is applied to each part of the copier, the input / output control 20 wakes up and starts the above-described “power supply control” PSCa.

  In this embodiment, the fixing power HRPt1 corresponding to AC1300W when fixing reload is performed to rapidly raise the fixing device temperature, and after the completion of fixing reloading and printing is started, the fixing power HRPt2 is equivalent to AC1200W for a while and printing is started and fixed. The fixing power HRPt3 after the device is sufficiently warmed is set to a value equivalent to 900W. The current upper limit value MCD that defines the upper limit value of the output current of the constant voltage power supply 30 is lowered when the fixing power HRP is increased, thereby reducing the AC power consumption by the constant voltage power supply 30. As a result, the insufficient load power is shared by the auxiliary power supply 32 (constant current power supply 26). When HRP is high (HRPt1), MCD is set to low (MCDt1). MCDt1 is an AC200W equivalent value. When HRP is medium (HRPt2), MCD can be medium (MCDt2). MCDt2 is an AC300W equivalent value. When HRP is low (HRPt3), MCD can be high (MCDt3). MCDt3 is an AC600W equivalent value. When Cv is equal to or less than the discharge prohibition threshold Vcs, the 24V load is all set to a high value MCDt3 shared by the constant voltage power supply 30. When the high value MCDt3 is set, the fixing power HRP is lowered so that the AC power consumption from the AC line 27 is 1500 W or less.

  In the second embodiment, the boost regulator 40 (FIG. 6) of the constant current power supply 26 of the auxiliary power supply 32 of the first embodiment is changed to a buck boost type buck-boost regulator 40a shown in FIG. Other configurations and functions are the same as those of the first embodiment described with reference to FIGS. 1 to 5 and FIGS. The electric double layer capacitor can use more stored electric power when the discharge stop voltage (discharge prohibition threshold Vcs) is lowered. Therefore, similarly to the first embodiment, the second embodiment shown in FIG. 11 is designed to be ½ of the full charge voltage. Therefore, the input voltage (capacitor voltage Cv) of the constant current power supply 26 is approximately half the value at the time of full charge immediately before the discharge is stopped, and the input current value of the constant current power supply 26 is approximately the input current at the time of full charge. It will double. When designing the output current of the constant current power supply 26 to be large, the number of electric double layer capacitors connected in series is increased so as not to increase the input current value (capacitor discharge current value) immediately before the discharge is stopped. It is necessary to prevent the capacitor voltage (Vcs) immediately before stopping the discharge from becoming small. In order to supply power to a 24V load, when the capacitor 37 of the auxiliary power supply 32 is composed of 10 to 19 electric double layer capacitors in series, the charging upper limit voltage (full charge voltage) is 24V. Since the discharge stop voltage is less than 24V, it is necessary to use a buck-boost regulator.

  Since the second embodiment uses the auxiliary power source 32 of this aspect, the DC / DC converter of the constant current power source 26 is a step-up / down regulator 40a shown in FIG. In the step-up / down regulator 40 a, in addition to the step-up output semiconductor switch 41, a step-down output second semiconductor switch 68 is interposed between the capacitor 37 and the reactor 43. The semiconductor switch 41 becomes conductive when H is applied to its gate, while the second semiconductor switch 68 becomes conductive when L is applied to its gate. The PWM controller 42 drives the semiconductor switch 41 and the semiconductor switch 68 on / off at a duty specified by the duty instruction signal. When the output voltage of the differential amplifier 50 decreases, the duty for turning on the semiconductor switch 68 is increased. While the on-duty of the semiconductor switch 68 is less than 100%, the on-duty of the semiconductor switch 41 is set to 0%. When the on-duty of the semiconductor switch 68 increases and reaches 100%, the on-duty of the semiconductor switch 41 is increased this time. When the output voltage of the differential amplifier 50 rises, the on-duty of the semiconductor switch 41 is lowered. While the on-duty of the semiconductor switch 41 is not 0%, the on-duty of the semiconductor switch 68 is set to 100%. When the on-duty of the semiconductor switch 41 reaches 0%, the on-duty of the semiconductor switch 68 is lowered this time. Thus, in the second embodiment, while the capacitor voltage Cv is higher than 24V, the switch 41 is off and the second switch 68 is repeatedly turned on / off by the PWM pulse, and the output voltage of the step-up / down regulator 40a is the capacitor voltage. It becomes approximately 24V lower than Cv. While the capacitor voltage Cv is higher than the discharge inhibition threshold Vcs but not more than 24V, the second switch 68 is on, and the switch 41 is repeatedly turned on / off by the PWM pulse as in the first embodiment, and the step-up / down regulator 40a. Output voltage is approximately 24V, which is higher than the capacitor voltage Cv.

  In the third embodiment, the step-up regulator 40 (FIG. 6) of the constant current power supply 26 of the auxiliary power supply 32 of the first embodiment is changed to a buck type step-down regulator 40b shown in FIG. The configuration and function are the same as those of the first embodiment described with reference to FIGS. 1 to 5 and FIGS. When the capacitor 37 of the auxiliary power supply 32 is obtained by connecting more electric double layer capacitors in series and the discharge stop voltage (discharge prohibition threshold Vcs) is set to a load voltage of 24 V or more (for example, 25 V), the constant current power supply 26 is Suppose that the step-down regulator 40b shown in FIG. 12 is used.

  The step-down regulator 40 b has a step-down output semiconductor switch 68 interposed between the capacitor 37 and the reactor 43. The semiconductor switch 68 becomes conductive when L is applied to its gate. The PWM controller 41 reverses the level of the same pulse as the PWM pulse generated by the PWM controller of the first embodiment while the power ON / OFF instruction signal (H: ON instruction / L: OFF instruction) is H. A corresponding PWM pulse is generated and applied to the gate of the semiconductor switch 68.

  In the fourth embodiment, the boost regulator 40 (FIG. 6) of the constant current power supply 26 of the auxiliary power supply 32 of the first embodiment is changed to a boost regulator 40c shown in FIG. This is the same as the first embodiment described with reference to FIGS. 1 to 5 and FIGS. The step-up regulator 40c used in the fourth embodiment is a forward type DC / DC converter using a step-up transformer 70. The configuration and function of the PWM controller 42 are the same as those of the PWM controller 42 (FIG. 6) of the first embodiment. When the power ON / OFF instruction signal is switched from H (on instruction) to L (off instruction), the PWM controller 42 stops the PWM pulse output, the switch 41 is continuously turned off, and the primary winding of the transformer 70 is turned off. Since energization stops, the discharge of the capacitor 37 stops. Since the power ON / OFF controller 55 used in the first embodiment can be omitted, it is omitted in the fourth embodiment. Note that the transformer 70 can be a step-down transformer and the regulator 40c can be a step-down regulator by changing the primary / secondary winding ratio of the transformer 70.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view showing an appearance of a multi-function copying machine MF1 equipped with a capacitor power supply device according to a first embodiment of the present invention. FIG. 2 is an enlarged vertical sectional view of the color printer 200 shown in FIG. 1. FIG. 2 is a block diagram showing a system configuration of an electric system of the copying machine MF1 shown in FIG. It is a block diagram which shows the outline | summary of a structure of the main power supply 29 and the auxiliary power supply 32 shown in FIG. It is a block diagram which shows the outline | summary of a structure of the input-output control 20 shown in FIG. 3 and FIG. FIG. 5 is an electric circuit diagram showing a configuration of a constant current power supply 26, a load current detector 33, and a current indicator 64 shown in FIG. 6A is a graph showing the load current detection signal level (vertical axis) generated in correspondence with the load current value (horizontal axis) of the load current detector 33 shown in FIG. 6, and FIG. A graph showing a current output instruction signal level (vertical axis) to the auxiliary power source 32 generated corresponding to the load current detection signal level (horizontal axis), (c) is a load current detection signal level (horizontal axis) of the load current detector 33. (D) is a graph showing the relationship between the output current value of the constant current power supply 26 and the constant voltage power supply 30, and (d) shows the output voltage (horizontal axis) of the constant current power supply 26 by the high voltage limiting function of the voltage limiter 51. It is a graph which shows the relationship with an output electric current value (vertical axis). Current value (d) of load 35, 24V current output upper limit value MCD of constant voltage power supply 30, 24V output current value (e) of constant voltage power supply 30, output current value (f) of constant current power supply 26, fixing power supply 31 6 is a time chart showing the relationship among AC power consumption (b), AC power consumption (c) due to 24V output of the constant voltage power supply 30, and AC power consumption (a) for the AC power supply line 27. It is a flowchart which shows the outline | summary of the electric power feeding control by the input / output control 20 (CPU21) shown in FIG. The fixing power HRP, the 24V current output upper limit value MCD of the main power supply 29, the current of the load 35 (load current), the 24V output current of the main power supply 29, and the output of the auxiliary power supply 32, which are operated by the power supply control of the input / output control 20 It is a time chart which shows the relationship with an electric current. It is an electric circuit diagram which shows the structure of the buck-boost regulator 40a of the constant current power supply 26 of 2nd Example. It is an electric circuit diagram which shows the structure of the pressure | voltage fall regulator 40b of the constant current power supply 26 of 3rd Example. It is an electric circuit diagram which shows the structure of the step-up regulator 40c of the constant current power supply 26 of 4th Example.

Explanation of symbols

201: Photoconductor
202: Charging device
203: Exposure apparatus
204, 207: Developing device
208, 215: Transfer belt
209 to 211: paper feed cassette
214: Fixing device
224: Paper discharge guide
225: Paper discharge roller
226: Output stack
227: Supply toner storage unit
233: Registration roller

Claims (30)

In a power supply device comprising: a first power source with a constant voltage output using power supplied from outside as an input source; a power storage device; and a second power source using power from the power storage device as an input source.
An output of a first power supply and an output of a second power supply are connected in parallel, and both the power from the first power supply and the power from the second power supply are simultaneously supplied to a load.   The power storage device according to claim 1, wherein the power storage device includes a capacitor.   The power supply device according to claim 2, wherein the capacitor is an electric double layer capacitor.   The power storage device according to claim 2, wherein the power storage device further includes a capacitor charging unit that charges the capacitor.   The power supply device according to any one of claims 1 to 4, wherein the second power supply is a constant current power supply.   The power supply apparatus further includes load current detection means for generating a load current signal representing a current value flowing through the load, and current instruction means for generating an output current instruction signal of a second power supply corresponding to the load current signal; The power supply device according to any one of claims 1 to 5, wherein the power supply includes current control means for controlling the output current of the second power supply to an output current value corresponding to the output current instruction signal.   7. The current instruction unit according to claim 6, wherein a difference between an upper limit instruction signal that specifies an upper limit of an output current value of a first power supply with respect to the load current signal is provided to the current control unit as the output current instruction signal. Power supply.   The current instruction means analog-converts upper limit instruction data into an upper limit instruction signal, and the difference of the upper limit instruction signal with respect to the load current signal is output to the current control means as the output current instruction signal. The power supply apparatus according to claim 7, further comprising difference calculation means for outputting.   The power supply device according to claim 7, further comprising a control unit that controls energization of the load and that supplies the upper limit instruction signal to the current instruction unit.   The power supply device according to claim 9, wherein the control means controls the current value that the first power supply supplies to the load by operating the upper limit instruction signal.   A second power source that transforms and outputs the power of the power storage device; a transformer regulator that can control the output power; current detection means that detects an output current value of the transformer regulator; and the output current value of the output current instruction signal Feedback control means for providing a control signal for adjusting to an instruction value to the voltage regulator, and supplying a constant current output of the voltage regulator to the load in addition to supplying power to the load of a first power source; Item 11. The power supply device according to any one of Items 1 to 10.   The power supply device according to claim 11, wherein the transformer regulator is a boost regulator.   The power supply device according to claim 11, wherein the transformer regulator is a step-up / down regulator.   The power supply device according to claim 11, wherein the transformer regulator is a step-down regulator.   The power supply device according to claim 11 or 12, wherein the transformer regulator is a boost type regulator.   The power supply device according to claim 11, wherein the transformer regulator is a forward regulator.   The second power supply includes overvoltage detection means for detecting an overvoltage in which a voltage at a constant current output terminal thereof exceeds a set value, and stops current output when the overvoltage is detected. Power supply.   The power supply apparatus further includes a third power source that is fed from a power feeding line that feeds power to the first power source from the outside and feeds a load that is separate from the load; and the control means increases the output power of the third power source. The power supply device according to claim 10, wherein the current value supplied to the load by the first power supply is reduced through the upper limit instruction signal;   The power supply device according to claim 18, wherein the control unit charges the power storage device with the charging unit while the output power of the third power supply is small.   The control means increases the value of the current supplied by the first power supply to the load via the upper limit instruction signal when the input power supply voltage used for constant current output of the second power supply is low. 19. The power supply device according to 19. An imaging device for forming an image on paper; and
The power supply device according to claim 9 or 10, wherein power is supplied to an electrical load of the imaging device;
An image forming apparatus comprising:   The image forming apparatus forms an electrostatic latent image on a photosensitive member, develops the electrostatic latent image into a toner image, and transfers the toner image directly or indirectly to a sheet via an intermediate transfer member. And a fixing device that includes a fixing heater and fixes the toner image on the paper to the paper; and the power supply device is further supplied with power from a power supply line that supplies power to the first power supply from the outside to supply power to the fixing heater. The image forming apparatus according to claim 21, further comprising: a third power source; wherein the first power source and the second power source of the power source supply power to a power load other than the fixing heater;   The control means increases the power distribution of the power supply line to the third power supply when raising the fixing temperature of the fixing device, and sets the current value that the first power supply supplies to the load via the upper limit instruction signal. The image forming apparatus according to claim 22, wherein the image forming apparatus is made smaller.   The control means lowers the power distribution of the power supply line with respect to a third power source when raising the fixing temperature of the fixing device and the voltage of the power storage device is low, and raises the upper limit instruction signal to increase the first power source. 24. The image forming apparatus according to claim 23, wherein a current value supplied to the load is increased.   When the standby mode in which image formation can be started in response to an image formation start instruction is continued for a set time without any user input or operation, the third power source is turned off and the first power supply is required for image formation. The image forming apparatus according to claim 22, wherein the image forming apparatus shifts to an energy saving mode in which a circuit unit that supplies power to a load is turned off.   The control means, after shifting to the energy saving mode, in response to a user instruction input or operation, turns on the third power supply and turns on the circuit section for supplying power to a required load for image formation of the first power supply. The image forming apparatus according to claim 25, wherein the image forming apparatus returns to the mode.   The control means lowers the upper limit instruction signal to reduce the current value supplied to the load by the first power source when the fixing temperature of the fixing device is raised immediately after the transition to the standby mode, and the fixing temperature 27. The image forming apparatus according to claim 26, wherein, after starting up, the upper limit instruction signal is raised to increase a current value of the first power supply supplying power to the load.   28. The image forming apparatus according to claim 27, wherein the control unit charges the power storage device with the charging unit when power supply from the second power supply to the load is stopped in the standby mode.   A printer controller that converts document information given from the outside into image data used for image formation of the image forming device; and an image forming control unit that forms an image represented by the image data in the image forming device. The image forming apparatus according to any one of claims 21 to 28. 30. The image forming apparatus according to claim 21, wherein the image reading apparatus generates image data representing an image projected by an optical system; and the image data is suitable for image formation by the image forming apparatus. An image data processing apparatus which converts the image signal into an image forming apparatus and supplies the image signal to the image forming apparatus.

Images