JP2009162902A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which can suitably switch charging or discharging of an accumulating type power source unit according to amount and types of jobs. <P>SOLUTION: The image forming apparatus includes: the accumulating type power source unit which can be charged by an AC power source unit; a load for the accumulating type power source unit, which can work between at the voltage which is lower than a prescribed discharge stopping voltage V1 and at the high voltage exceeding the discharge stopping voltage V1, regarding the accumulating type power source unit; a charging control means for controlling charging to the accumulating type power source apparatus; a discharging control means controlling the discharging to the load from the accumulating type power source unit; and a control means carrying out control of the power source. The control means sets discharge starting voltage V2 (when V2>V1) for the accumulating type power source unit according to the amount of the job, instructs the charging control means to discharge to the accumulating type power source unit. After that, when detection is made that the voltage of the accumulating type power source unit has reached the discharge starting voltage V2, discharging to the load from the accumulating type power source unit is instructed by the image forming apparatus. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming apparatus that forms an image using an electrophotographic method or the like, and more particularly to an image forming apparatus that includes a power storage type power supply device.

  2. Description of the Related Art Conventionally, in an image forming apparatus represented by an electrophotographic copying machine, when the image forming apparatus is in operation due to an increase in copying speed or a multifunctional copying system including applications such as an automatic document feeder and a sorting apparatus. Power consumption tends to increase.

  On the other hand, a commercial power source, which is a power source of this type of image forming apparatus, is normally limited to an AC voltage of 100 V and 15 A or less because of equipment.

  By the way, in the image forming apparatus, heat and pressure are applied by the heat fixing device in order to fix the visualized toner image on the recording paper on the recording paper, but the temperature of the heat fixing device is low when the power is turned on in the morning. A large amount of power is required to raise the temperature in a short time. However, since the rating of the commercial power source is limited to 100 V and 15 A or less as described above, it is difficult to raise the temperature of the thermal fixing device to a predetermined temperature in a short time. Therefore, in addition to the main power source, a storage type power source is provided as an auxiliary power source. By supplying power from the electricity storage type power supply to the thermal fixing device, the temperature of the thermal fixing device is raised to a predetermined temperature in a short time while keeping the AC power input to the image forming apparatus below the rated power. It has been proposed to let

  Here, if the power storage type power supply continues to supply power to the load, naturally the voltage gradually decreases, so that it becomes impossible to supply necessary power to the load at a certain value. Usually, before that happens, it is common to stop the power supply to the load when a predetermined voltage value is detected, and shift to a charging mode in which the storage power source is charged.

Therefore, when power is supplied to the load from the power storage type power supply, power supply to the load is permitted if the voltage of the power storage type power supply is greater than or equal to a certain threshold, and depending on the operation status of the device if the voltage is less than the certain threshold A method of selecting whether or not to charge is proposed (Patent Document 1).
JP 2005-221745 A

  However, if the voltage (accumulated energy) falls below a certain threshold while power is being supplied from the storage power source to the load, if it continues to be used without being charged, the power necessary to drive the load will gradually be lost, and eventually It causes problems such as load function stop and device operation stop.

  On the other hand, it is assumed that charging is selected when the voltage (accumulated energy) falls below a certain threshold value while power is being supplied from the storage power source to the load. Then, as shown in section a of FIG. 4, the voltage of the power storage type power supply gradually increases and exceeds the threshold value. Then, this time, it immediately switches to the discharge mode and begins to supply power to the load, so that the voltage of the power storage type power supply decreases as shown in the section b. Then, the switching operation is repeated many times in a short time, such as switching to the charging mode when the value falls below the threshold value, so that it becomes a so-called chattering state. Switching noise and excessive inrush current flow. As a result, there is a possibility of causing malfunction of the apparatus, destruction of elements, and the like.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus capable of appropriately switching charging / discharging of a power storage type power supply device according to the amount and type of a job. It is what.

  In order to solve the above problems, in the present invention, the image forming apparatus is configured as described in (1) and (2) below.

(1) an image forming unit that forms an image based on the input job;
A DC power supply device that converts AC power from an external AC power source into DC power;
A power storage device that can be charged by the DC power supply; and
A load of the storage-type power supply device operable from a voltage lower than a predetermined discharge stop voltage V1 related to the storage-type power supply device to a high voltage exceeding the discharge stop voltage V1,
Charging control means for controlling charging from the DC power supply device to the electricity storage type power supply device;
Discharge control means for controlling discharge from the power storage type power supply device to the load;
Voltage detecting means for detecting the voltage of the power storage type power supply device;
Control means for controlling the power supply;
With
The control means sets a discharge start voltage V2 (where V2> V1) of the power storage type power supply device according to the amount of the job, and charges the charge control means from the DC power supply device to the power storage type power supply device. And then, when the voltage detecting means detects that the voltage of the power storage power supply has reached the discharge start voltage V2, the discharge control means discharges the load from the power storage power supply to the load. An image forming apparatus for instructing.

(2) a DC power supply device that converts AC power from an external AC power source into DC power;
A power storage device that can be charged by the DC power supply; and
A load of the storage power supply device operable from a voltage lower than a predetermined discharge stop voltage V1 related to the storage power supply device to a high voltage exceeding the discharge stop voltage V1,
Charging control means for controlling charging from the DC power supply device to the electricity storage type power supply device;
Discharge control means for controlling discharge from the power storage type power supply device to the load;
Voltage detecting means for detecting the voltage of the power storage type power supply device;
Control means for controlling the power supply;
With
The control means sets a discharge start voltage V2 (where V2> V1) of the power storage type power supply according to the type of job, and charges the charge control means from the DC power supply to the power storage type power supply. And then, when the voltage detecting means detects that the voltage of the power storage power supply has reached the discharge start voltage V2, the discharge control means causes the discharge from the power storage power supply to the load. An image forming apparatus for instructing.

  According to the present invention, it is possible to provide an image forming apparatus capable of appropriately switching charging / discharging of a power storage type power supply device according to the amount and type of a job.

  Hereinafter, the best mode for carrying out the present invention will be described in detail by way of examples of embodiments.

[Embodiment 1]
The image forming apparatus according to the first embodiment will be described. Since the image forming operation itself is a general electrophotographic method and is well known, a description of a series of image forming operations is omitted.

FIG. 1 is a block diagram showing a schematic configuration of an image forming apparatus (a multi-function machine having both a copying function, a printer function, and a FAX function) according to the present embodiment. As illustrated, the present embodiment includes a digital color image reader unit 300 and a digital color image printer unit 100.
A control unit 1 controls the DC load 4 (motor, clutch, etc.) of the printer unit 100 to perform an image forming operation and communicates with the reader unit 300, and is generally called a DC controller. As will be described later, the control unit 1 further detects the voltage of the auxiliary power supply unit and controls charging and discharging of the auxiliary power supply unit. A fixing unit 2 fixes the toner image transferred onto the recording paper by heat. Reference numeral 3 denotes a DC power supply unit (corresponding to a DC power supply device in claims), which supplies power to the control unit 1, the DC load 4, and the reader unit 300. Reference numeral 5 denotes a DC / DC converter, which converts a DC voltage supplied from the DC power supply unit 3 into a DC voltage required by the reader unit 300. Reference numeral 6 denotes an auxiliary power supply unit (corresponding to a power storage type power supply device that can be charged by a DC power supply device in claims), and in the present embodiment, is constituted by an electric double layer capacitor. Reference numeral 7 denotes a switching unit for switching whether the power supplied to the DC / DC converter 5 is the DC power supply unit 3 or the auxiliary power supply unit 6 according to the power consumption. Reference numeral 8 denotes an AC load such as a heater for drying the recording paper.

  The electric power supplied from the commercial power supply AC100 is supplied to the DC power supply unit 3 and the fixing unit 2 via a main switch (not shown). The DC power source unit 3 converts AC power supplied from a commercial power source AC 100 (corresponding to an external AC power source in claims) into DC power, and applies it to various DC loads 4 such as the control unit 1 of the image forming apparatus, a motor, and a clutch. Supply. With this power supply, the fixing unit 2 and the DC load 4 perform a predetermined image forming operation. Further, the switching unit 7 switches the switch of the switching unit 7 to the A terminal side in accordance with an instruction from the control unit 1 during standby, sleep, or operation, and supplies a charging current control signal Sig1 to the switching element 9 to provide a DC power source. The auxiliary power supply unit 6 is charged from the unit 3. That is, the switching unit 7 controls the discharge of the auxiliary power supply unit 6, and the switching element 9 controls the charging of the auxiliary power supply unit 6.

  At the time of charging, the terminal voltage of the auxiliary power supply unit 6 increases substantially linearly as shown in FIG. The control unit 1 monitors the terminal voltage of the auxiliary power supply unit 6. When the full charge voltage is reached, the control unit 1 switches the switch of the switching unit 7 to the B terminal side and cuts off the charging current control signal Sig1 to turn off the switching element 9. State and finish charging.

  Here, the input voltage necessary for the DC / DC converter 5 to operate normally is not a constant value, but may be in a range of a certain value or more. In the present embodiment, the input voltage range necessary for outputting 24V is 13V to 24V. However, 13V <discharge stop voltage V1 <24V described later (corresponding to being operable from a voltage lower than the predetermined discharge stop voltage V1 to a voltage exceeding the discharge stop voltage V1).

Therefore, when the printer unit 100 receives an operation command for an image forming job when it is charged to the discharge stop voltage V1 or higher in FIG. 2, it is possible to accept only that job. However, in this case, since the terminal voltage of the auxiliary power supply unit 6 drops to V1 or less at an early stage as shown in FIG. 2A, the job may be changed depending on the length of the received job (the number of images formed in the job). Switch to charging mode immediately after interruption.
Further, when the job is finished before the discharge stop voltage is lowered to V1 or lower, the charging mode is entered after the job is finished.

  The operation sequence performed by the control unit 1 will be described with reference to the flowchart of FIG. Processing of this sequence is performed by a CPU (not shown) in the control unit 1. When the printing operation is started (S2, YES) in a state where the voltage of the auxiliary power supply unit 6 is charged to the discharge stop voltage value V1 or more (S2, YES), the control unit 1 outputs a switching signal to output the switching unit. 7 is switched to the B terminal side, and the auxiliary power supply unit 6 is set to the discharge mode (S3). As a result, discharge starts from the auxiliary power supply unit 6. The voltage supplied from the auxiliary power supply unit 6 is converted into a desired voltage by the DC / DC converter 5, and each load of the reader unit 300 is driven. As a result, the voltage of the auxiliary power supply unit 6 gradually decreases and continues to decrease until the job is completed. Then, the control unit 1 checks the voltage of the auxiliary power supply unit 6 after the job is finished (S4). If the voltage is equal to or higher than the discharge stop voltage V1 (NO in S4), it checks whether the next job exists (S6). If a job exists, the discharge mode is maintained and the job is accepted (S3). If there is no next job (S6, NO), the control unit 1 places the image forming apparatus in a standby state (S7). Then, the control unit 1 determines whether or not the charging is completed to the voltage value V1 or higher (YES in S1, NO in S2, NO in S5), and shifts to the charging mode (S8). In the charging mode, the switch of the switching unit 7 is switched to the A terminal side by a signal from the control unit 1, and the switching element 9 receives the signal Sig. 1 is turned on to charge the electric double layer capacitor. If charging is completed, the mode is not shifted to the charging mode (YES in S1, NO in S2, YES in S5, NO in S6, S7).

  If the voltage of the auxiliary power source 6 after the job is less than V1 (S4, YES), the control unit 1 checks whether the next job exists, and if it does not exist (NO in S9), the battery is charged. Transition to mode (S8). If there is a next job (YES in S9), the control unit 1 checks the print amount (number of pages) of the job (S10), calculates the necessary current amount from the operation time, etc. Is determined to set the discharge start voltage V2 (S11). That is, the discharge start voltage V2 is set to the voltage side close to full charge for a job with a print amount of tens of pages, and the discharge stop voltage V1 side is set for a job with a short print amount of about one page or several pages. The discharge start voltage V2 is set to a close voltage.

  Then, the control unit 1 charges the battery until the discharge start voltage V2 or higher is monitored while monitoring the voltage of the auxiliary power supply unit 6 (S12, S13) and holds the job, and displays that charging is being performed on a display unit (not shown). . That is, the control unit 1 also functions as voltage detection means.

  When the voltage of the auxiliary power supply unit 6 is charged to the discharge start voltage V2 or more (S13, YES), the control unit 1 outputs a switching signal to the switching unit 7 by a signal, and the contact of the switching unit 7 is moved to the B terminal side. Let them switch. Further, the control unit 1 outputs the signal Sig1 to turn on the switching element 9 to shift to the discharge mode, and accepts the held job and performs the printing operation (S6, S3).

  As described above, according to the present embodiment, charging / discharging switching of the storage power source can be appropriately performed according to the print amount (corresponding to the job amount in the claims).

In this embodiment, the value of the discharge start voltage V2 is determined according to the print amount of the job. However, the set value of the discharge start voltage V2 is automatically set according to the type of job to be recorded next. May be. Examples of job types include a SEND operation in which only the reader operates, a print operation in which only the printer operates, and a FAX transmission / reception operation in which only the FAX operates.
In addition, manual setting such that the battery type power supply is not discharged until the power storage type power supply is fully charged is also possible according to user settings (corresponding to manual changeable claims). In the present embodiment, the job is held until the charging voltage of the capacitor of the auxiliary power supply unit 6 becomes equal to or higher than the discharge start voltage V2. The operation may be performed while suppressing the current consumption. Alternatively, printing may be performed at a printing speed corresponding to the power from the DC power supply unit 3 without suspending the job.
In the present embodiment, the start and stop of discharge of the auxiliary power supply unit 6 are controlled by switching the switch of the switching unit 7. However, the present invention is not limited to this, and the start and stop of discharge of the auxiliary power supply unit may be controlled by driving or non-driving the DC / DC converter or the like without switching the switch or using the switch.

1 is a block diagram illustrating a schematic configuration of an image forming apparatus according to a first embodiment. Diagram showing charge / discharge operation of capacitor The flowchart which shows the operation | movement sequence of Embodiment 1. The figure which shows the history of the voltage at the time of charge and discharge of the capacitor The figure which shows the switching circuit of the charge of the capacitor in an image forming apparatus, and discharge

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Control part 3 DC power supply part 5 DC / DC converter 6 Auxiliary power supply part 7 Switching part 9 Switching element

Claims (4)

An image forming unit for forming an image based on the input job;
A DC power supply device that converts AC power from an external AC power source into DC power;
A power storage device that can be charged by the DC power supply; and
A load connected to the storage power supply device operable from a voltage lower than a predetermined discharge stop voltage V1 related to the storage power supply device to a high voltage exceeding the discharge stop voltage V1;
Charging control means for controlling charging from the DC power supply device to the electricity storage type power supply device;
Discharge control means for controlling discharge from the power storage type power supply device to the load;
Voltage detecting means for detecting the voltage of the power storage type power supply device;
Control means for controlling the power supply,
The control means sets a discharge start voltage V2 (where V2> V1) of the power storage type power supply device according to the amount of the job, and charges the charge control means from the DC power supply device to the power storage type power supply device. And then, when the voltage detection means detects that the voltage of the electricity storage power supply has reached the discharge start voltage V2, the discharge control means causes the discharge from the electricity storage power supply to the load. An image forming apparatus characterized by A DC power supply device that converts AC power from an external AC power source into DC power;
A power storage device that can be charged by the DC power supply; and
A load of the storage power supply device operable from a voltage lower than a predetermined discharge stop voltage V1 related to the storage power supply device to a high voltage exceeding the discharge stop voltage V1,
Charging control means for controlling charging from the DC power supply device to the electricity storage type power supply device;
Discharge control means for controlling discharge from the power storage type power supply device to the load;
Voltage detecting means for detecting the voltage of the power storage type power supply device;
Control means for controlling the power supply;
With
The control means sets a discharge start voltage V2 (where V2> V1) of the power storage type power supply according to the type of job, and charges the charge control means from the DC power supply to the power storage type power supply. And then, when the voltage detection means detects that the voltage of the power storage power supply has reached the discharge start voltage V2, the discharge control means causes the discharge from the power storage power supply to the load. An image forming apparatus characterized by instructing. The image forming apparatus according to claim 1, wherein
The image forming apparatus, wherein the discharge start voltage V2 can be manually changed. The image forming apparatus according to any one of claims 1 to 3,
The image forming apparatus, wherein the power storage type power supply device includes an electric double layer capacitor.

Images