JP2007244144A - Power source apparatus and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ensure convenience for users by detecting an output abnormality of a second power source as an auxiliary power source in an early stage, and preventing incomplete image forming due to the output abnormality. <P>SOLUTION: A power source apparatus is provided with a first power source 30 of constant voltage output which uses power to be input from the outside as an input power source, a power accumulator 37, and a second power source 26 of a constant current output which uses the power from the power accumulator as an input power source and outputs a current of a level instructed by a current indicating signal Sio. The output of the first power source is connected in parallel to the output of the second power source, and both the power from the first power source and the power from the second power source are simultaneously supplied to a load 35. Further, the apparatus is provided with monitoring means 70, 20 for monitoring a feedback control signal Sm for controlling the constant current of the second power source. <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 using the power as an input source in addition to a power supply using electric power supplied from the outside in a steady state, and is not particularly limited to this. However, when a large amount of power is required for the operation of the entire device, the power stored in the power storage device is supplied to the DC load so that the AC power of the device does not exceed the power that can be supplied by the power source. It is related with the power supply device which can be made. The present invention can be applied to, for example, a backup power supply when power supply is interrupted 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, and a printer, copying machine, and facsimile apparatus.

  For example, an electrophotographic image forming apparatus such as a copying machine or a printer is composed of a photosensitive member, a charging unit provided around the photosensitive member, an exposure unit, a developing unit, a transfer unit, and a transfer sheet. And a fixing device for fixing the toner image transferred to the toner image. The fixing device is provided with a fixing roller incorporating a heater. A heater control device is also provided for controlling energization of the heater in order to keep the temperature of the fixing roller constant.

  Such an image forming apparatus is required to have a fast rise time before printing can be performed when the power is turned on or when returning from the energy saving mode to the operation mode. In general, the factor that most affects the rise time is the rise of the fixing temperature, and increasing the rise of the fixing temperature leads to shortening the rise time until printing is possible. Recently, an image forming apparatus that can be connected to an external device via a network has become common, and the image forming apparatus is often used while being energized. When the energy saving mode returns to the standby mode, Therefore, it is important to shorten the rise time.

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

  However, since there is a limit to the power that can be supplied from a normal power supply line, this is a major limitation in designing the equipment. In order to avoid exceeding the maximum suppliable power of the power supply line, Patent Document 1 predicts the used power consumption, and when the predicted power consumption exceeds the suppliable power of the main power supply, for some loads. A power supply device and an image forming apparatus that supply power of a main power supply and an auxiliary power supply by a switching circuit are 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, and backflow to the main power supply is prevented 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. An image forming apparatus that supplies power to a load only from an auxiliary power source during a higher period is described.

  However, in the conventionally known technology, the power output circuit of the power storage device, that is, the power feeding circuit to the load is configured by a constant voltage power source, and therefore, the output of the AC / DC power source (main power source) which is a constant voltage power source by the switching circuit. In addition, when the output of the auxiliary power source, which is also a constant voltage power source, is switched and supplied to the load, voltage fluctuation occurs at the time of switching due to the output voltage difference between the two constant voltage power sources. When voltage fluctuation occurs, the operation of the motor that supplies power becomes unstable, and there is a problem that the motor stops or rotation unevenness occurs. Uneven rotation of the motor causes an image abnormality of the image forming apparatus. For example, in the case of a color image forming apparatus, color misregistration occurs.

-Information on prior application-
The present applicant presented a power supply device and an image forming apparatus equipped with the power supply device in Japanese Patent Application No. 2005-335889 (filing date: November 21, 2005). The power supply device includes a first power source having a constant voltage output using an externally supplied power as an input source, a power storage device, and a second power source using the power of the power storage device as an input source. The outputs of the two power sources are connected in parallel, and both the power from the first power source and the power from the second power source are supplied to the load at the same time. Another power supply apparatus and an image forming apparatus equipped with the power supply apparatus were presented in Japanese Patent Application No. 2006-26774 (filing date: February 3, 2006). The power supply apparatus detects the output current value of the first power supply and controls the output of the second power supply so as to be equal to or lower than the upper limit instruction value MCD for the first power supply in order to prevent overload to the external power supply. To do.

  The power supply devices presented in Japanese Patent Application Nos. 2005-335889 and 2006-26774 use a second power source (auxiliary power source) that outputs stored power of a power storage device as a constant current power source, and outputs a power of an external power source. The output of the first power supply (main power supply), which is a voltage power supply, and the output of the second power supply are connected in parallel to supply both the power from the first power supply and the power from the second power supply to the load at the same time. The power supply switching from one to the other is eliminated, and the voltage fluctuation due to the switching is suppressed. These power supply devices detect the load current obtained by combining the current values supplied from the first and second power supplies to the 24V system load 35 or the current values supplied from the first power supply to the 24V system load 35, and detect the detected current value and the first current value. The output current value of the second power supply is controlled according to the upper limit instruction value MCD for one power supply.

  However, it is conceivable that the second power supply fails. Even if the second power supply does not fail, it is also conceivable that the output operation of the second power supply appears to be out of the steady operation due to the abnormality of the power storage device (37) or the shortage of power storage. If the output of the second power supply drops abnormally, the output of the first power supply increases to compensate for this, and the power consumption of the first power supply to the external power supply increases, exceeding the maximum suppliable power of the external power supply line. It is possible that

  The first object of the present invention is to detect an output abnormality of the second power supply at an early stage, and in the case of an image forming apparatus using the second power supply and the fixing device, the first power supply is reduced due to a decrease in the output abnormality of the second power supply. A second object is to prevent an overload applied to an external power source via the second, and a third object is to ensure user convenience.

(1) A first power source (30) having a constant voltage output using externally supplied power as an input source, a power storage device (37), and a current indication signal (Sio) using the power of the power storage device as an input source The second power source (26) having a constant current output that outputs a current at a level indicated by the power source is connected, the output of the first power source and the output of the second power source are connected in parallel, and the power from the first power source and the second power source are In a power supply that supplies both of the power of
A power supply apparatus comprising: monitoring means (70, 20) for monitoring a feedback control signal (Sm) for constant current control of the second power supply (26). In addition, in order to make an understanding easy, the code | symbol of the corresponding element or the corresponding matter of the Example which is shown in drawing and mentions later in a parenthesis was added as an example for reference. The same applies to the following.

  The feedback control signal for constant current control represents a level within a predetermined range determined from the specifications of the second power source. Therefore, when the feedback control signal (Sm) is outside the predetermined range that is defined as normal, the second power source (26) can be determined to be abnormal, and the abnormality of the second power source can be detected at an early stage.

  (2) The second power source (26) includes a current control means (46) for generating the feedback control signal (Sm) for adjusting the output current level to the instruction level of the current instruction signal, and the feedback control signal. The power supply device according to (1), further including a voltage transformation regulator (40) that transforms and outputs the electric power of the power storage device (37) corresponding to (Sm).

  (3) The power supply apparatus according to (1) or (2), wherein the monitoring means (70, 20) performs an abnormality process including a warning when the feedback control signal (Sm) is outside a predetermined range. According to this, the user can recognize that the operation of the second power source (26) is abnormal.

  (4) The image forming apparatus (200) for forming an image on a sheet; and the power source described in any one of (1) to (3) above for supplying electric power to an electrical load (35) of the image forming apparatus An image forming apparatus.

  (5) 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 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; the monitoring means (70, 20); If the feedback control signal (Sm) is outside the predetermined range, the maximum power supply to the fixing device is lowered and the power supply from the second power source (26) is stopped; the image according to (4) above Forming equipment.

  Since the power consumption of the first power source (30) relative to the AC power source can be increased by changing the maximum power supply to the fixing device low, the load to be shared by the second power source (26) is the first power source. (30) bears and the AC power consumption of the first power supply (30) increases, but the sum of the AC power consumption of the fixing device and the first power supply (30) does not increase, and the AC power consumption is excessive. It becomes possible to prevent the load in advance. Since the supply of power from the second power source (26) is stopped, an increase in the abnormality of the second power source (26) can be avoided.

  (6) When the fixing temperature reaches the lower limit temperature, the monitor means (70, 20) widens the image forming pitch (paper interval: paper feed interval) of the image forming device (200); The image forming apparatus described in 1. By lowering the maximum power supply to the fixing device, the fixing power is reduced, but the image formation pitch is widened, so the heat storage time (heat up time) of the fixing device between papers becomes longer and one image is formed. There is no reduction in the heat of fixing to the paper, and the image formation amount (sheets / minute) is reduced, but the image forming quality is not lowered.

  (7) The monitor means (70, 20) decreases the electrostatic latent image forming speed (linear speed: sub-scanning speed) of the image forming device (200) when the fixing temperature reaches the lower limit temperature; The image forming apparatus according to (5). By lowering the maximum power supply to the fixing device, the fixing power is reduced, but the image forming speed (linear speed: sub-scanning speed) is widened, so the fixing temperature drop during fixing is small, and the fixing device between papers The heat storage time (heat up time) becomes longer and the amount of fixing heat for one image forming sheet is not reduced, and the image forming quality (sheet / min) is reduced, but the image forming quality is not lowered.

  (8) When the fixing temperature reaches the lower limit temperature, the monitoring means (70, 20) temporarily stops the image forming operation of the image forming device (200) and waits for the fixing temperature to rise; ). Since the fixing temperature rises while the image forming operation is temporarily stopped, it is possible to secure the fixing quality when the image forming operation is resumed. Although the image forming amount (sheets / minute) is reduced, the image forming quality is not deteriorated.

  (9) The original image is read by the scanner even while the image forming operation is temporarily stopped; the image forming apparatus according to (8) above. Since the power consumed for reading the original image by the scanner is small, the heat-up of the fixing device while the image forming operation is temporarily stopped is not particularly impaired. Image data can be stored in a memory and used for image formation after the fixing temperature has been recovered, and a user can read and store a copied document.

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

-1st Example-
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 temperature of the fixing device due to heat generated by the fixing heater 36 of the fixing device 214 (FIG. 2) within the phase angle limit corresponding to the power upper limit instruction signal given from the input / output control 20 as a target value (reload target value). The power supply thyristor is triggered to conduct at a thyristor conduction phase angle to match (/ 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 power upper limit instruction signal.

  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 supplies the constant current power supply 26 with a current instruction signal Sio 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 Sio as a target value. The feedback control signal Sm used for constant current control inside the constant current power supply 26 is also given to the A / D converter 70 outside the power supply 26, and the input / output control 20 converts the feedback control signal Sm into the A / D converter 70. Then, it is converted into digital data, that is, feedback control data Sm, and is read. Based on the control data Sm, the presence or absence of an output abnormality of the constant current power supply 26 is determined.

  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 copy or print instruction in the standby mode, 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 (target current value to be borne by the constant current power supply 26) Sio of the current indicator 64 increases and the output voltage Sm (feedback control signal) of the differential amplifier 50 decreases, Increase the duty of the PWM pulse. 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 Sm 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 Sio (current instruction signal) 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 increases the PWM control signal Sm, which is a feedback 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 the present embodiment, the PWM pulse duty instruction signal (feedback control signal) Sm is digitally converted by the A / D converter 70 of FIG. When the input / output control 20 detects that the digitally converted value is outside a predetermined range, it performs an abnormality process such as a warning.

  FIG. 9 shows the state 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 SW 28 from OFF to ON or returning from the energy saving mode to the standby mode. An outline of the “fixing power control” DPC started by the output control 20 (CPU 21 thereof) is shown. In the standby mode in which the operating voltage required for printing and copying is applied to each part of the copying machine MF1, the input / output control 20 reads the fixing temperature from the fixing power source 31 (step 1). In the following, in the steps, the word “step” is omitted and only the step number is written.

  If the read fixing temperature is lower than the fixing reload temperature, the fixing temperature is insufficient, and it is necessary to raise the temperature, that is, to reload the fixing. Therefore, it is determined whether the auxiliary power source 32 can supply power (the charging voltage of the capacitor 38 is at a power supply level). (2, 3) When the power supply is possible, the input / output control 20 outputs the current upper limit data MCD for high-speed fixing reload to the current indicator 64 and instructs the power ON / OFF controller 55 to turn on the power. Give a signal. That is, power supply from the auxiliary power source 32 to the load 35 is started (4). In addition, a high power distribution upper limit value that allows high power consumption is given to the fixing power source 31 (5). In response to this, the fixing power source 31 starts a rapid fixing reload with high power consumption.

  Since the power ON / OFF controller 55 provides an operation instruction signal to the PWM controller 42 of the boost regulator 40 in response to the power ON instruction signal, the PWM controller 42 provides a PWM instruction signal which is a feedback control signal provided by the output current controller 46. A PWM pulse having a duty indicated by Sm is generated and applied to the semiconductor switch 42. As a result, the boost regulator 40 starts discharging the power of the capacitor 37, that is, feeding power to the load 35.

  The current indicator 64 outputs a current indication signal Sio representing a difference value obtained by subtracting the current upper limit value MCD addressed to the constant voltage power source 30 output from the current indicator 64 from the load current value detected by the load current detector 33. The current controller 46 is given as an output current target value of the constant current power supply 26. The output current controller 46 outputs the actual output current value corresponding to an error signal obtained by subtracting the actual output current value of the constant current power supply 26 (the output of the differential amplifier 48) from the output current target value Sio. The PWM instruction signal Sm is generated and output to the PWM controller 42.

  As shown in FIG. 8, the power consumption pattern of the copying machine MF1 is substantially fixed although there is a slight variation depending on the temperature inside and outside the copying machine MF1, and therefore the output of the constant current power supply 26 is also the same as that shown in FIG. As shown, the level range of the PWM instruction signal Sm is within a predetermined range when the constant current power supply 26 operates normally and supplies power to the load 35. This predetermined range is called a normal range. The fact that the level of the PWM instruction signal Sm deviates from this predetermined range is considered to be a circuit abnormality or an operation abnormality of the constant current power supply 26 and / or a shortage or abnormality of the power storage of the capacitor 37.

  Referring to FIG. 9 again, when the input / output control 20 starts feeding from the auxiliary power supply 32 (constant current power supply 26) (4, 5), the A / D converter 70 converts the PWM instruction signal Sm into digital data, that is, PWM. It is converted into instruction data Sm and read (6), and it is determined whether it is within a predetermined range, that is, whether the auxiliary power supply 32 is operating normally (7).

  While the PWM instruction data Sm is not out of the predetermined range, the fixing temperature is monitored, and if the fixing temperature is lower than the fixing reload temperature, fixing reload is necessary. Therefore, power supply from the auxiliary power source 32 to the load 35 is performed. Continue (6-9). When the fixing temperature becomes equal to or higher than the fixing reload temperature, the fixing reload is unnecessary, and thus the high power supply to the fixing heater (rapid rise in fixing temperature) is stopped. That is, a low power distribution upper limit value for designating low power consumption is given to the fixing power source 31 (10). Then, a power OFF instruction signal is given to the power ON / OFF controller 55 (11).

  When the PWM instruction data Sm is out of the predetermined range, the input / output control 20 notifies the abnormality of the auxiliary power supply 32 to the engine control 510, and the engine control 510 displays the abnormality on the operation board 10 via the printer controller 501. (12). In addition, the input / output control 20 gives the fixing power source 31 a low power distribution upper limit value that designates low power consumption (13). In response to this, the fixing power source 31 switches the fixing heater temperature control to the heater temperature control with low power consumption. The input / output control 20 further gives a power OFF instruction signal to the power ON / OFF controller 55. That is, power supply from the auxiliary power source 32 to the load 35 is stopped (14). After that, the fixing temperature is monitored, and when the fixing temperature falls below the lower limit temperature for fixing processing, the engine control 501 is notified of the necessity of extending the paper feed interval (repeating paper feeding and feeding pitch). The control 501 changes the paper feed interval to a long pitch for fixing heater low power supply (15 to 17). When the fixing temperature returns to the fixing reload temperature (lower limit value that requires fixing reload) or more, the paper feed interval is restored (18 to 20). Table 1 below shows an example of a normal paper feed interval (90 mm) and a heater power (900 W) required at that time, a paper feed interval (270 mm) to be lengthened, and a heater power (700 W) required at that time.

  In summary, when the auxiliary power supply 32 is determined to be abnormal, the fixing power supply 31 reduces the maximum power supply of the heater of the fixing device 214 and stops the supply of power from the auxiliary power supply 32. Since the fixing power supply 31 reduces the maximum power supply to the heater of the fixing device 214 to control the heater temperature, the temperature of the fixing unit may gradually decrease depending on conditions such as paper size, environmental temperature, and continuous printing time. . When the temperature of the fixing unit is lowered, the fixing property is lowered, and the image quality is seriously affected. Therefore, when the fixing unit temperature reaches the fixing unit lower limit temperature, the productivity of printing is lowered by lengthening the gap between the printing papers, but the temperature of the fixing unit is increased to prevent the temperature from decreasing.

  When the paper interval is made longer, the temperature of the fixing unit gradually rises, and when the temperature of the fixing unit becomes higher than the fixing unit reload temperature, the paper interval is restored so that the printing productivity is restored. The fixing portion reload temperature is, for example, 170 ° C., and the fixing portion lower limit temperature is, for example, 160 ° C. During normal printing, the fixing unit temperature is controlled to be maintained at 170 ° C. It becomes a severe environment for fixing, and it becomes impossible to maintain the fixing unit temperature at 170 ° C. When the fixing unit temperature gradually decreases to 160 ° C., the control is performed to reduce the productivity by increasing the interval between the printing sheets. By reducing the productivity, the environment for fixing is improved, and the temperature of the fixing unit gradually increases and returns to the fixing unit control temperature of 170 ° C.

  According to the first embodiment, the input / output control 20 monitors the PWM instruction signal Sm, which is a feedback control signal, while supplying power from the auxiliary power supply 32 to the load 35. Assuming that the power supply 32 is abnormal, the abnormality is displayed on the operation board 10 and the heater power upper limit value of the fixing power supply 31 is lowered to stop the output of the auxiliary power supply 32. The power supply is not overloaded, and the expansion of the abnormality of the auxiliary power supply 32 can be avoided. When the fixing temperature is lowered due to power shortage, the paper feeding interval is widened, so that the image forming speed (sheets / minute) is reduced, but printing can be continued and the required fixing temperature can be maintained. The decline is small.

-Second Example-
The hardware of the second embodiment is the same as that of the first embodiment described above, but the contents of the “fixing power control” of the input / output control 20 of the second embodiment are the same as those of the first embodiment (FIG. 9). Is a little different.

  FIG. 10 shows the contents of the “fixing power control” DPCa of the input / output control 20 of the second embodiment. This “fixing power control” DPCa monitors the fixing temperature when the PWM instruction data Sm is out of the predetermined range, and when the fixing temperature falls below the lower limit temperature for fixing processing, The engine control 501 notifies the engine control 501 that the conveyance speed (sub-scanning speed) needs to be reduced, and the engine control 501 changes the sub-scanning speed to a low speed for fixing heater low power supply (15 to 17a). When the fixing temperature returns to the fixing reload temperature or higher, the sub-scanning speed is restored (18 to 20a). Other processes are the same as those in the first embodiment shown in FIG. Table 2 below shows an example of a normal linear velocity (200 mm / sec) and a heater power (900 W) required at that time, and a low linear velocity (125 mm / sec) and a heater power (700 W) required at that time.

  In the second embodiment, when the fixing unit temperature reaches the fixing unit lower limit temperature, the linear speed of printing is decreased, thereby preventing the temperature of the fixing unit from decreasing. After lowering the line speed, if the temperature of the fixing part gradually increases and the temperature of the fixing part rises above the reloading temperature of the fixing part, the linear speed is reduced so that the printing productivity is restored. Revert.

-Third embodiment-
The hardware of the third embodiment is the same as that of the first embodiment, but the contents of the “fixing power control” of the input / output control 20 of the third embodiment are the same as those of the first embodiment (FIG. 9). Is a little different.

  FIG. 11 shows the contents of the “fixing power control” DPCb of the input / output control 20 of the third embodiment. The “fixing power control” DPCb monitors the fixing temperature when the PWM instruction data Sm is out of a predetermined range, and controls the engine to stop feeding when the fixing temperature falls below the lower limit temperature for fixing processing. 501 is notified, and the engine control 501 stops paper feeding (15 to 17b). The engine control 510 continues reading the document image by the scanner 100 even while the paper feeding is temporarily stopped. When the fixing temperature returns to the fixing reload temperature or higher, the input / output control 20 informs the engine control 501 that the paper feeding can be started, and the engine control 501 resumes paper feeding (18 to 20b). Other processes are the same as those in the first embodiment shown in FIG.

  In the third embodiment, when the fixing unit temperature reaches the fixing unit lower limit temperature, paper feeding (printing) is temporarily stopped, so that the temperature of the fixing unit is prevented from decreasing and the recovery of the fixing temperature is awaited. During this time, if the document reading is incomplete, the document reading by the scanner 100 continues. After stopping the paper feeding, when the fixing unit temperature gradually rises and becomes higher than the fixing reload temperature, the paper feeding (printing) is resumed so as to restore the printing productivity.

1 is a front view showing an external appearance of a multi-function copying machine MF1 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. 6 is a flowchart showing an outline of fixing power control by an input / output control 20 (CPU 21) shown in FIG. It is a flowchart which shows the outline | summary of the fixing electric power control by the input / output control 20 (CPU21) of 2nd Example. It is a flowchart which shows the outline | summary of the fixing electric power control by the input / output control 20 (CPU21) of 3rd 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 (9)

A first power source with a constant voltage output that uses power supplied from the outside as an input source, a power storage device, and a constant current output that outputs current at a level indicated by a current instruction signal using the power of the power storage device as an input source In the power supply apparatus, the output of the first power supply and the output of the 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 the load.
A power supply apparatus comprising: monitoring means for monitoring a feedback control signal for constant current control of the second power supply.   A second power source configured to generate the feedback control signal for adjusting the output current level to the instruction level of the current instruction signal; and to output the power of the power storage device in response to the feedback control signal. The power supply device according to claim 1, further comprising: a voltage-transforming regulator.   The power supply apparatus according to claim 1, wherein the monitoring unit performs an abnormality process including a warning when the feedback control signal is outside a predetermined range. An imaging device for forming an image on paper; and
The power supply device according to any one of claims 1 to 3, 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 monitoring means has a maximum power supply to the fixing device when the feedback control signal is outside a predetermined range. And the supply of power from the second power supply is stopped;   The image forming apparatus according to claim 5, wherein the monitor unit widens an image forming pitch of the image forming device when a fixing temperature reaches a lower limit temperature.   The image forming apparatus according to claim 5, wherein the monitor unit reduces an electrostatic latent image forming speed of the image forming device when a fixing temperature reaches a lower limit temperature.   The image forming apparatus according to claim 5, wherein when the fixing temperature reaches a lower limit temperature, the monitor unit temporarily stops the image forming operation of the image forming apparatus and waits for an increase in the fixing temperature. The image forming apparatus according to claim 8, wherein a document image is read by a scanner even while the image forming operation is temporarily stopped.

Images