JP3853274B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus that forms an image on a sheet, and more particularly, to an image forming apparatus that includes a heater for keeping a stored sheet warm.
[0002]
[Prior art]
Conventionally, an image forming apparatus that forms an image on a sheet such as a copying machine, a facsimile machine, or a printer supplies power to all parts involved in image formation while the main switch (power switch) is set to ON. It was kept in a standby mode in a state where it can be supplied and an image can be immediately formed according to the instruction. However, this is not a preferable control method from the viewpoint of reducing power consumption. Therefore, a power-saving mode is provided to reduce power consumption by stopping power supply to parts with high power consumption, including parts that are involved in image formation. Is automatically switched to the power saving mode.
[0003]
Many image forming apparatuses store sheets in the apparatus so that images can be formed at any time. In such an image forming apparatus, the stored sheets may absorb moisture, resulting in inconveniences such as poor image transfer to the sheets, sheet clogging, sheet wrinkling, and warping. In view of this, moisture absorption is prevented by providing a heater in a part for storing the sheet and keeping the sheet at a predetermined temperature. In general, an image forming apparatus stores a plurality of types of sheets having different sizes and orientations separately, and a heater for keeping warm is provided for each group of separated sheets. In order to prevent moisture absorption during a period in which no image is formed, power is supplied to the heater even in the power saving mode.
[0004]
[Problems to be solved by the invention]
However, the conventional image forming apparatus supplies power to the heater for keeping the sheet warm regardless of whether or not the stored sheet is present. That is, power is supplied to the heater even when the sheets are not stored, or even after the sheets are consumed due to image formation. For this reason, the situation of consuming electric power in order to keep the sheet | seat which does not exist has arisen, and electric power consumption cannot fully be reduced. In particular, in an image forming apparatus that stores a plurality of types of sheets, it is difficult for the user to notice that one of the types of sheets is lost, and the heater often consumes power wastefully.
[0005]
The present invention has been made in view of such problems, and an image forming apparatus capable of preventing moisture absorption of a sheet provided with a heater while preventing wasteful power consumption by the heater. The purpose is to provide.
[0006]
[Means for Solving the Problems]
To achieve the above object, according to the present invention, an image includes a forming unit that forms an image on a sheet, a supply unit that stores the sheet and supplies the sheet to the forming unit, and a heater that keeps the sheet in the supply unit warm. The forming apparatus includes a sensor that detects the presence or absence of a sheet in the supply unit, and supplies power to the heater only when the sensor detects that there is a sheet in the supply unit. As long as the sensor is in operation, it is possible to detect the presence or absence of a sheet in the supply unit, and when there is no sheet in the supply unit, power is not supplied to the heater, and power is consumed to keep the non-existent sheet warm. Can be avoided.
[0007]
The image forming apparatus takes, for example, a power supply unit that supplies power to be supplied to the heater, a closed state in which the power supply unit and the heater are connected, and an open state in which the power supply unit and the heater are not connected. This is realized by providing a latch-type relay circuit that maintains the open / closed state set up to.
[0008]
In this configuration, when it is detected that no sheets have been stored due to image formation, the relay circuit is opened, and the power consumption of the heater thereafter can be eliminated. When it is detected that the sheet has been replenished, the relay can be closed and the replenished sheet can be kept warm by the heater. Furthermore, since this relay circuit keeps the open / closed state set until instructed, even when the power supply to the relay circuit itself or the part giving the instruction is stopped and then the power supply is resumed, The open / close state does not change. For example, the power supply unit and the heater are not connected even when the power supply is stopped in a state where the sheet is lost due to image formation and the power supply is restarted. Therefore, there is no situation where the heater wastes power to keep the non-existing sheet warm.
[0009]
The image forming apparatus includes a power supply stop mode in which power is not supplied to the forming unit and the supply unit, and includes a communication unit that performs facsimile communication, and supplies power to the communication unit in the power supply stop mode to supply power. When received in the stop mode, the power supply stop mode is terminated, power is supplied to the forming unit and the supply unit, and the received data is formed on the sheet as an image. In this way, the facsimile apparatus can consume less power, can always receive data, and can form received data as an image as long as there is a sheet.
[0010]
In particular, in the configuration including the relay circuit, power supply to the relay circuit can be stopped in the power supply stop mode and restarted when the power supply stop mode ends. In this way, it is possible to control the power supply to the relay circuit and the power supply to the forming unit and the supply unit in exactly the same manner, and the control is facilitated and the configuration for control is simplified. . Moreover, even when the user replenishes or removes the sheet during the power supply stop mode, the state of power supply to the heater can be automatically switched when the sheet is received thereafter.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 schematically shows the configuration of the digital copying machine 1 according to the first embodiment. The digital copying machine 1 includes a forming unit 10 that forms an image on a sheet, a supply unit 20 that supplies the sheet to the forming unit 10, a reading unit 30 that reads a document image, and an operation / display that is operated by a user and displays information. A control unit 50 that controls the overall operation of the copying machine 1, and a power supply unit 60 that converts AC power from a commercial power source into DC power and supplies the DC power to the control unit 50.
[0012]
The copying machine 1 employs a system in which a charged photosensitive drum is exposed to form a latent image, developed by attaching toner to the latent image, and the toner image on the photosensitive drum is transferred to a sheet. . Although not shown, the forming unit 10 includes a photosensitive drum, a charging unit, an exposure unit, a developing unit, a transfer unit, a fixing unit, and the like.
[0013]
The supply unit 20 includes a plurality of cassettes 21 and can store sheets of different sizes and orientations for each cassette 21. Each cassette 21 is provided with a heater 22 that keeps stored sheets and a sensor 23 that detects the presence or absence of sheets.
[0014]
The reading unit 30 has a CCD line sensor, reads a document image by the CCD line sensor, and outputs it as a digital signal. The operation / display unit 40 has several keys for accepting user operations, and also has a liquid crystal display for displaying information.
[0015]
The control unit 50 supplies DC power supplied from the power supply unit 60 to the forming unit 10, the supply unit 20, and the reading unit 30, and controls the operation of these parts. For example, the reading unit 30 is controlled to read a document image, the digital signal output from the reading unit 30 is processed to generate image data representing the read image, and the forming unit 10 and the supplying unit 20 are further controlled. The image represented by the image data is formed on the sheet. The control unit 50 also controls power supply from itself to each unit and also controls power supply to the heater 22 of the supply unit 20. This control is performed based on the detection result of the sensor 23.
[0016]
A configuration relating to the control of the heater 22 of the copying machine 1 is shown in FIG. There are two power supply paths from the power supply unit 60 to the control unit 50, and a main switch 61 is provided on one of them. By opening the main switch 61, supply of a part of electric power to the control unit 50 is stopped. The control unit 50 supplies power supplied via the main switch 61 to each unit including the forming unit 10. Although power is always supplied to the control unit 50 from a supply path in which no switch is provided, the control unit 50 uses this power for its own operation. The main switch 61 is operated by the user, and the open / close state can be switched by the control unit 50.
[0017]
AC power from a commercial power source is supplied to the heater 22 of the supply unit 20. A relay circuit 70 is connected to the heater 22, and power supply to the heater 22 is controlled by opening and closing the relay circuit 70. The configuration of the relay circuit 70 is shown in FIG.
[0018]
Each relay circuit 70 includes two input terminals 71a and 71b connected to a commercial power source, two output terminals 72a and 72b connected to the heater 22, an input terminal 71a and an output terminal 72a, and an input terminal 71b and an output. Two switches 73a and 73b for closing and opening the terminal 72b are provided. The relay circuit 70 also includes an open circuit 74 and a close circuit 75 that drive the switches 73a and 73b to switch the open / close states of the input terminals 71a and 71b and the output terminals 72a and 72b. The open circuit 74 is provided with a terminal 74a to which a control signal HOFF is given from the control unit 50, and a constant voltage terminal 74b to which a constant voltage (24V) is given from the control unit 50. A terminal 75a to which a control signal HON is given from the unit 50 and a constant voltage terminal 75b to which a constant voltage (24V) is given from the control unit 50 are provided.
[0019]
The control signal HOFF instructs opening of the input terminals 71a and 71b and the output terminals 72a and 72b, and the control signal HON instructs closing of the input terminals 71a and 71b and the output terminals 72a and 72b. . The open circuit 74 and the close circuit 75 operate when these control signals HOFF and HON are given, and the control unit 50 does not always output the control signal HOFF or the control signal HON, but the input terminals 71a and 71b. When the open / close state of the output terminals 72a and 72b is switched, one of them is output. The switches 73a and 73b are of a latch type that maintains the already set state until the setting is changed by the open circuit 74 or the close circuit 75, and the relay circuit 70 is in an open / closed state until a switching instruction is given. . That is, the relay circuit 70 maintains an open / closed state even when power is not supplied.
[0020]
The controller 50 controls the opening and closing of the relay circuit 70 individually for each cassette 21 based on the output signal SP from the sensor 23. In FIG. 2, only two cassettes 21, heaters 22, sensors 23, and relay circuits 70 are shown for simplification, and control signals HON and HOFF to each relay circuit 70 and each sensor 23 are shown. Although the output signal SP is not distinguished, the heater 22, the sensor 23, and the relay circuit 70 exist as many as the number of the cassettes 21, the timing when the control unit 50 gives the control signals HON and HOFF, and the content of the output signal SP of the sensor 23. Depends on the cassette 21.
[0021]
The copying machine 1 supplies power to all parts involved in image formation, and includes a standby mode in which an image can be immediately formed in response to an instruction, and power including a part involved in image formation. It has a power saving mode in which the power supply to the parts with high consumption is stopped to reduce the power consumption. It also has a function of automatically switching from the standby mode to the power saving mode when a state in which no image is formed continues for a predetermined time. Switching between these modes is performed by the control unit 50 giving a control signal MON / OFF to the power supply unit 60 to switch the open / close state of the main switch 61.
[0022]
The control unit 50 uses the power supplied from the power supply unit 60 without passing through the main switch 61 for its own control operation as described above, but also supplies it to a predetermined key in the operation / display unit 40. Therefore, the predetermined key can be operated even in the power saving mode, and the user instructs switching to the standby mode by operating this key.
[0023]
In the power saving mode, power is not supplied except for the predetermined keys of the control unit 50, the heater 22, and the operation / display unit 40, and is not supplied to the relay circuit 70. On the other hand, in the standby mode, power is normally supplied to all parts of the copying machine 1. However, when the sensor 22 detects that no sheet is present in the cassette 21, power is not supplied to the heater 22 of the cassette 21. That is, the control unit 50 sets the relay circuit 70 of the cassette 21 to an open state.
[0024]
The flow of control of power supply to the heater 22 is shown in the flowchart of FIG. First, it is determined whether the main switch 61 of the power supply unit 60 is open or closed, that is, whether it is in the standby mode or the power saving mode (step # 105). When the main switch 61 is closed, that is, in the standby mode, the presence or absence of a sheet in each cassette 21 is determined from the output signal of the sensor 23 (# 110). If there is a sheet, the relay circuit 70 is closed. The electric power is supplied to the heater 22 while maintaining the connected state or switching from the open state to the closed state (# 115). Then, the process returns to step # 105. If there is no seat, the relay circuit 70 is kept open or switched from the closed state to the open state, and power is not supplied to the heater 22 (# 120). Then, the process returns to step # 105.
[0025]
If it is determined in step # 105 that the main switch 61 is open, that is, in the power saving mode, the process returns to step # 105 without switching the open / close state of the relay circuit 70, and power is supplied to the heater 22. Keep the power on or power off.
[0026]
In the above control, when all the sheets stored in the cassette 21 are consumed by image formation, the power supply to the heater 22 is stopped in step # 120. In the standby mode, when a sheet is supplied to the cassette 21 that is out of sheets, power supply to the heater 22 is started in step # 115. Furthermore, when the cassette 21 runs out of sheets and shifts to the power saving mode and returns to the standby mode, the power supply to the heater 22 remains stopped.
[0027]
In the power saving mode, the user may supply sheets to the cassette 21. In this case, after the sheet is replenished, the user may switch to the standby mode by operating a predetermined key of the operation / display unit 40. In step # 115, power supply to the heater 22 is started, the replenished sheet is kept warm, and the mode returns to the power saving mode after a predetermined time.
[0028]
In the copying machine 1 that performs such control, power consumption when an image is not formed can be reduced, and wasteful power consumption for keeping a sheet that does not exist can be eliminated. Moreover, when the sheet exists, it is possible to reliably keep the sheet warm and prevent moisture absorption.
[0029]
The configuration of the facsimile apparatus 2 of the second embodiment is schematically shown in FIG. The facsimile apparatus 2 is obtained by adding a communication unit 80 for performing facsimile communication and a sub power supply unit 90 to the digital copying machine 1 of the first embodiment. There is only one cassette 21 in the supply unit 20 for storing sheets. In the facsimile device 2, the image read by the reading unit 30 can be formed on a sheet by the forming unit 10, or can be transmitted to another facsimile device via the communication unit 80. In addition, data received from other facsimile machines can be formed on a sheet as an image by the forming unit 10.
[0030]
The configuration of the control unit 50, the power supply unit 60, the communication unit 80, and the sub power supply unit 90 is shown in FIG. The communication unit 80 is connected to the telephone line L and is also connected to the control unit 50. The control unit 50 and the communication unit 80 exchange information related to control and transmission / reception data. In the facsimile apparatus 2, a main switch 91 is provided in the sub power supply unit 90, and a part of power supply to the control unit 50 is controlled by a relay circuit 92 that is linked to the main switch 91. The communication unit 80 is supplied with power from the sub power supply unit 90.
[0031]
Similarly to the digital copying machine 1, the facsimile apparatus 2 has a standby mode and a power saving mode, and switches from the standby mode to the power saving mode when a state in which no image is formed continues for a predetermined time. Even in the power saving mode, power is supplied to the communication unit 80, and switching between the standby mode and the power saving mode is performed by the communication unit 80 switching the open / close state of the main switch 91 by the control signal MON / OFF.
[0032]
Even in the power saving mode, the facsimile apparatus 2 to which power is supplied to the communication unit 80 can always perform facsimile reception. However, in the power saving mode, power is not supplied to the forming unit 10 and the supply unit 20, and thus an image cannot be formed. Therefore, when a facsimile is received in the power saving mode, the mode is switched to the standby mode, and the received data is formed on the sheet as an image. However, even when receiving in the power saving mode, if there is no sheet in the cassette 21, the received data is stored.
[0033]
The power supply to the sheet heat retaining heater 22 is performed via the relay circuit 70 as in the digital copying machine 1. The control is almost the same as in the copying machine 1, and the control unit 50 performs based on the presence or absence of a sheet. The only difference from the control of the copying machine 1 is that it switches to the standby mode when receiving a facsimile in the power saving mode.
[0034]
The flow of control of power supply to the heater 22 is shown in the flowchart of FIG. First, it is determined whether the main switch 91 (and the relay circuit 92) of the sub power supply unit 90 is open or closed, that is, whether it is in the standby mode or the power saving mode (step # 205). When the main switch 91 is closed, that is, in the standby mode, the presence or absence of a sheet in the cassette 21 is determined from the output of the sensor 23 (# 210). If there is a sheet, the relay circuit 70 is closed. Or switching from the open state to the closed state to supply power to the heater 22 (# 215). If there is no seat, the relay circuit 70 is kept open or switched from the closed state to the open state, and power is not supplied to the heater 22 (# 220).
[0035]
If the main switch 91 is open in the determination of step # 205, that is, in the power saving mode, it is determined whether or not a facsimile is received (# 225). When the facsimile is received, the main switch 91 is determined. Is closed to switch to the standby mode (# 230), and the process proceeds to step # 210. Thereafter, if there is a sheet in the determination in step # 210, a process of forming received data on the sheet as an image is performed separately from the heater control process in step # 215. If the facsimile reception is not made in the determination of step # 225, the process returns to step # 205, and the state where the power is supplied to the heater 22 or the state where the power supply is stopped is maintained.
[0036]
In the facsimile apparatus 2 that performs such control, power consumption when an image is not formed can be reduced, and useless power consumption for keeping a sheet that does not exist can be eliminated. Moreover, when the sheet exists, it is possible to reliably keep the sheet warm and prevent moisture absorption. Further, it is possible to always receive a facsimile, and as long as a sheet exists, the received data can be immediately formed as an image.
[0037]
A third embodiment will be described. In the present embodiment, the digital copying machine 1 of the first embodiment is modified so that the power supply path from the power supply unit 60 to the control unit 50 is only one system through the main switch 61. When the main switch 61 is open, power is not supplied to the control unit 50, and power supply to the respective units such as the forming unit 10 and the supply unit 20 by the control unit 50 and control of each unit are not performed.
[0038]
The relay circuit 70 maintains the already opened / closed state even when a constant voltage of 24 V is not applied from the control unit 50. Therefore, when the main switch 61 is opened by shifting to the power saving mode, Even when the main switch 61 is opened by operation, if power is supplied to the heater 22 immediately before that, the power supply to the heater 22 is continued, and if the power supply to the heater 22 is stopped, the heater is stopped. The power supply to 22 remains stopped.
[0039]
While the main switch 61 is open, if the user replenishes the cassette 21 with no sheets, or removes the sheet from the cassette 21 for some reason, the control unit 50 does not operate. The open / close state of the relay circuit 70 cannot be switched. In this case, after the user finishes replenishing or removing the sheet, the user may operate the main switch 61 to close it. When the main switch 61 is closed, power supply to the control unit 50 is resumed and the standby mode is set, and the control unit 50 can switch the open / close state of the relay circuit 70 according to the output of the sensor 23.
[0040]
A mode in which power supply to the control unit 50 that controls not only the parts directly involved in image formation but also those parts as in the present embodiment is called an off mode. Both the power saving mode of the first and second embodiments in which power is supplied to the control unit 50 and the off mode of the present embodiment in which power supply to the control unit 50 is not performed are performed. This is included in the power supply stop mode in which no power is supplied.
[0041]
A fourth embodiment will be described. In the present embodiment, the facsimile apparatus 2 of the second embodiment is modified so that the power supply path from the power supply unit 60 to the control unit 50 is only one system through the relay circuit 92 and is controlled when the main switch is open. The above-described off mode in which power is not supplied to the unit 50 is provided.
[0042]
Even in the off mode, power is supplied from the sub power supply unit 90 to the communication unit 80, so that facsimile communication is possible. Further, when the facsimile reception is performed in the off mode, the communication unit 80 can close the main switch 91. Therefore, it is possible to return to the standby mode and form the received data on the sheet as an image. Even when the user replenishes a sheet to the cassette 21 or removes a sheet from the cassette 21 during the off mode, the control unit 50 outputs the output of the sensor 23 when the sheet is received and returned to the standby mode. Accordingly, since the open / close state of the relay circuit 70 is switched, it is not necessary for the user to perform an operation of closing the main switch 91.
[0043]
A fifth embodiment will be described. This embodiment modifies the first and second embodiments that supply power to the control unit 50 in the power saving mode, and supplies power from the control unit 50 to the sensor 23 that detects the presence or absence of sheets in the cassette 21. Is also performed in the power saving mode, and when the detection result of the sensor 23 changes, the open / close state of the relay circuit 70 is switched. In this way, after the user replenishes the sheet in the cassette 21 or removes the sheet from the cassette 21 during the power saving mode, the user presses the key on the operation / display unit 40 that instructs to return to the standby mode. Even when the operation is not performed, the power supply to the heater 22 can be reliably switched according to the presence or absence of a sheet.
[0044]
Although the sensor 23 also consumes power, the power consumption of the sensor 23 is much less than the power consumption of the heater 22, so that even if power is supplied to the sensor 23 in the power saving mode, the power consumption increases only slightly. Only. Further, the power supply to the sensor 23 in the power saving mode may not be continuously performed, but may be performed at a predetermined time interval (for example, every 5 minutes) for several seconds.
[0045]
Here, examples of a digital copying machine and a facsimile machine have been described. However, the present invention can also be applied to a printer, and can also be applied to a composite image forming apparatus having all these functions. Can do.
[0046]
【The invention's effect】
In an image forming apparatus including a forming unit that forms an image on a sheet, a supply unit that stores the sheet and supplies the sheet to the forming unit, and a heater for keeping the sheet of the supply unit warm, as in the present invention, the supply unit If a sensor for detecting the presence or absence of a sheet is provided and power is supplied to the heater only when the sensor detects the presence of a sheet in the supply unit, power is consumed to keep the non-existent sheet warm. It becomes possible to avoid the waste.
[0047]
The power supply unit that supplies power to the heater, the closed state in which the power supply unit and the heater are connected, and the open state in which the power supply unit and the heater are not connected are connected. By providing a latch-type relay circuit to be maintained, the image forming apparatus having the above-described effects can be realized with a simple configuration, and the control becomes extremely easy.
[0048]
A power supply stop mode that does not supply power to the forming unit and the supply unit, and a communication unit that performs facsimile communication is provided. When power is supplied to the communication unit in the power supply stop mode and received in the power supply stop mode. When the power supply stop mode is terminated and power is supplied to the forming unit and the supply unit, and the received data is formed on the sheet as an image, power consumption is low, and reception is always possible, as long as there is a sheet. The facsimile apparatus can form received data as an image. In particular, in a configuration including a latch-type relay circuit, power supply to the relay circuit can be stopped in the power supply stop mode and restarted at the end of the power supply stop mode, which facilitates control. In addition, the configuration for control is simplified, and even when the user replenishes or removes the sheet during the power supply stop mode, the state of power supply to the heater is automatically detected when it is received thereafter. It is possible to switch.
[Brief description of the drawings]
FIG. 1 is a diagram schematically illustrating a configuration of a digital copying machine according to a first embodiment.
FIG. 2 is a diagram showing a configuration relating to control of a sheet heat retaining heater of the digital copying machine.
FIG. 3 is a diagram showing a configuration of a relay circuit connected to a sheet heat retaining heater of the digital copying machine.
FIG. 4 is a flowchart showing a flow of control of power supply to a sheet heat retaining heater in the digital copying machine.
FIG. 5 is a diagram schematically illustrating a configuration of a facsimile apparatus according to a second embodiment.
FIG. 6 is a diagram illustrating a configuration of a control unit, a power supply unit, a communication unit, and a sub power supply unit of the facsimile apparatus.
FIG. 7 is a flowchart showing a flow of control of power supply to a sheet heat retaining heater in the facsimile apparatus.
[Explanation of symbols]
1 Digital copier
2 facsimile machines
10 Formation part
20 Supply section
21 cassette
22 Heater
23 Sensor
30 Reading unit
40 Operation / display section
50 Control unit
60 Power supply
61 Main switch
70 Relay circuit
71a, 71b input terminals
72a, 72b Output terminal
73a, 73b switch
74 Open circuit
74a Control terminal
74b Constant voltage terminal
75 closed circuit
75a Control terminal
75b constant voltage terminal
80 Communication Department
90 Sub power supply
91 Main switch
92 Relay circuit
HON, HOFF relay circuit control signal
MON / OFF main switch control signal
SP sensor output signal

Claims (2)

A forming unit that forms an image on the sheet, a supply unit that stores the sheet and supplies the sheet to the forming unit, a heater that keeps the sheet in the supply unit warm , a sensor that detects the presence or absence of the sheet in the supply unit, and a sensor When the sensor detects that there is a sheet in the supply unit and generates a control signal for permitting the supply of power from the power supply means to the heater, the sheet is supplied to the supply unit. When the sensor detects that there is no power, the control unit generates a control signal for prohibiting the supply of power from the power supply unit to the heater, and the power supply unit until the control signal is given from the control unit And a latch-type relay circuit that maintains the power supply from the heater to the previous permitted state or prohibited state,
An image forming apparatus having a power supply stop mode for stopping power supply to a forming unit and a supply unit,
The control unit intermittently supplies power to the sensor, detects the output of the sensor, and generates the control signal in the power supply stop mode . A communication unit for performing facsimile communication is provided.
Supply power to the communication unit in the power supply stop mode,
2. The image formation according to claim 1, wherein when receiving in the power supply stop mode, the power supply stop mode is ended, power is supplied to the forming unit and the supply unit, and the received data is formed on the sheet as an image. apparatus.

Images