JPH09258614A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the safety of a device by immediately driving in a printing mode specially used and preventing the deterioration of a power supply switch in the image forming device of a printer or the like. SOLUTION: In the image forming device 1, a carrying belt 12 is arranged on a lower side at the time of, for instance, monochromatic printing, and image forming processing is performed by an image forming unit 24, and the carrying belt 12 is moved upward at the time of color printing and a color image is formed by the image forming units 21-23. In this case, before turning off a power supply switch 42 with electromagnetic reset function when the image forming processing is finished, it is set to the printing mode frequently used, for instance, a color printing mode and the power supply, switch 42 with the electromagnetic reset function is turned off. After the image forming device 1 stops driving equipments using a large amount of electric power, for instance, a fixing device 4, the power supply switch 42 with the electromagnetic reset function of the image forming device 1 is turned off.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus using a single or a plurality of image forming units.

[0002]

2. Description of the Related Art As an image forming apparatus such as a printer,
There is known an image forming apparatus that performs color printing using a plurality of image forming units together with an image forming apparatus that performs monochrome printing using black toner. As an image forming apparatus for performing such color printing, for example, yellow (Y), magenta (M), cyan (C), and black (BK) image forming units are sequentially arranged, and a toner image of each color is transferred onto a sheet. There is known a so-called tandem type image forming apparatus that performs a heat fixing process after performing the above, and performs color printing on a sheet. In this type of image forming apparatus, color print processing using yellow (Y), magenta (M), cyan (C) image forming units and monochrome print processing using black (BK) image forming units are performed. be able to.

FIG. 13 is a diagram for explaining a tandem type image forming apparatus, in which yellow (Y), magenta (M), cyan (C), and the like are provided above a conveyor belt 50 for conveying the paper P.
Image forming units 51 to 54 for transferring black (BK) toner are provided. When performing monochrome printing, only the black (BK) image forming unit 54 is used, and the black toner is transferred by the corresponding photosensitive drum 54a and transfer roll 54b. On the other hand, when performing color printing, the drive roll 56 shown in the figure is moved upward and the image forming units 51 to 53 for yellow (Y), magenta (M), and cyan (C) are moved via the conveyor belt 50.
The (photosensitive drum) moves to a position where it abuts on the corresponding transfer roll. Then, the toner transfer process is sequentially performed,
The fixing device 57 performs a heat fixing process to melt and fix the toner.

Therefore, in the conventional image forming apparatus, the above-described movement processing of the drive roll 56 is required at the time of mode conversion from monochrome printing to color printing or from color printing to monochrome printing. For example, FIG. 14 is a flow chart for explaining this processing. When the CPU (not shown) receives a print start command (step (hereinafter referred to as S) 1
Is Y), it is judged whether the apparatus is in the color printing mode (S2), and if it is in the color printing mode, it is judged whether the above-mentioned conveyor belt 50 is in the raised state (up position) (S3), and as shown in FIG. For example, when the transport belt 50 is in the lowered state, the drive roll 56 is driven to raise the drive roll 56 to a predetermined position (S4). After that, each image forming unit 5
1 to 53 are driven to sequentially transfer the toner to the paper (S
5) By a heat fixing process, for example, the laminated toner images are melted to form a desired color image. Thereafter, a standby operation process is performed to wait for the next print process (S6).

On the other hand, if the apparatus is in the monochrome printing mode, it is judged whether the above-mentioned conveyor belt 50 is in the lowered state (down position) (S7). If the conveyor belt 50 is not in the lowered state, the driving roll 56 is driven. Then, the drive roll 56 is lowered to a predetermined position (S8). Then, the image forming unit 54 is driven to transfer the black toner onto the paper, and the heat fixing process is performed to heat-fix the toner image on the paper P (S9). Thereafter, a standby operation process is performed to wait for the next print process (S10). After that, when the print start signal is not received (S1 is N), the CPU determines whether or not the power off command is received (S11), and when the power off command is received, the power switch is turned off and reset driving is performed (S12).

Further, in the conventional image forming apparatus, the disconnection of the power switch described above is executed immediately when the power off command is input. FIG. 15 is a flow chart for explaining this power shutoff process. That is, it is judged whether or not the power-off command is received (step (hereinafter, referred to as ST) 1), and when the power-off command is not received (ST1 is N), the image forming apparatus performs the normal printing operation (ST2), and the power-off is performed. Wait for a command. After that, when the power off command is received (ST1 is Y), it is judged whether the current mode of the apparatus is the standby state (ST
3) If not in the standby state (ST3 is N), execute the print operation process (ST4) and the standby operation process (ST5),
After that, when the power switch is reset, the power switch is disconnected (ST6). On the other hand, when the above determination is in the standby state (ST3 is Y), the power switch is immediately turned off (ST6).

When the power switch of the image forming apparatus is cut off, the reset switch of the power switch is performed, for example, when the printer as the image forming apparatus is installed in a place apart from the host computer and the printer is powered by remote control. Used when cutting.

[0008]

The conventional image forming apparatus described above has the following problems. First, (a) in the conventional image forming apparatus, when the power is turned off in the monochrome print mode, the monochrome print mode is set when the apparatus is driven next. That is, this is the mode when the image forming apparatus is used last time. Therefore, even if the user wants to drive the apparatus and immediately execute color printing, he must wait until the mode is changed. Particularly, for a user who frequently performs color printing, the process of moving the drive roll 56 described above has to be performed frequently, which is a waste of time. On the contrary, this can be said to a user who frequently performs monochrome printing, and if the mode at the end of the previous image forming apparatus is the color printing mode, it takes time to convert to the monochrome printing mode.

Further, in the conventional image forming apparatus, when the power off command is input, the power switch is immediately turned off in the standby state. For this reason, in the case of a power switch with an electromagnetic reset function, which is used in an image forming apparatus installed in a remote place, a large current flows through the power switch, and in particular, the fixing device 57 is used to drive the heat roll. , When the power switch is cut off, arc discharge occurs, the contact of the switch deteriorates, and the life of the switch is shortened significantly.
Also, the arc discharge deteriorates the insulation and reduces the safety.

In order to solve the above problems, the present invention is to provide an image forming apparatus which can be immediately driven in a printing mode to be used, prevents deterioration of a power switch, and improves the safety of the apparatus.

[0011]

According to the present invention, in the image forming apparatus having a plurality of image forming processing modes, there is provided a mode identifying means for identifying an operation mode of the image forming processing and a power cutoff processing. Identifying means for identifying
When the identifying means identifies the power shutoff process, after the device power is shut down, if the state of the device is in the process mode of low use frequency, after changing the state to the process mode of high use frequency, This can be achieved by providing a power cutoff processing control means for executing the power cutoff processing.

With this configuration, the image forming apparatus can be used in the frequently used printing mode immediately after the power is turned on, and the time-efficient printing process can be performed. The frequently used processing mode is, for example, a color printing mode, and the less frequently used processing mode is, for example, a monochrome printing mode. Note that this mode may be reversed.

Further, according to the present invention, according to the present invention, a color image forming apparatus having a color image forming processing mode and a single color image forming processing mode is initialized when a period in which no print processing is performed continues for a predetermined time or more. This can be achieved by providing a color image forming apparatus that controls the return to the print mode.

Further, according to the present invention, according to the present invention, in a color image forming apparatus having a color image forming processing mode and a single color image forming processing mode, if a period during which printing processing is not performed continues for a predetermined time or more, power saving control is performed. This can be achieved by providing a color image forming apparatus that has a power saving control unit that shifts to a mode, and that the power saving control unit performs return control to the initialization printing unit before switching to the power saving state.

With this configuration, mode conversion can be performed even when the power is not turned on. For example, in the sleep mode, if the image forming process is not performed for a certain period of time, the device is converted into the print mode in which the device is frequently used. ,
It is possible to perform printing with high print processing efficiency.

Also in the above case, the frequently used processing mode is, for example, a color printing mode, and the less frequently used processing mode is, for example, a monochrome printing mode. Note that this mode may be reversed.

The initialization print mode is, for example, a color image forming processing mode, and the initialization print mode is, for example, a single color image forming processing mode. Further, according to the present invention, according to the present invention, in the image forming apparatus including the power supply control means for a large current load and the self power supply cutoff device for cutting off the power supply of the device in response to a command from the remote device, When the power cutoff device receives the power cutoff command, it can be achieved by providing an image forming apparatus that causes the power supply control unit to perform control for prohibiting the supply of power to the large current load before executing the power cutoff process.

With this configuration, when the power is shut off, the power supply to the large current load is always stopped first and then the power to the image forming apparatus is shut off, so that the power switch is not deteriorated.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is an overall configuration diagram of an image forming apparatus for explaining an example of the first embodiment of the present invention.
The image forming apparatus used in the description of this example is a so-called tandem color printer.

In FIG. 1, the image forming apparatus 1 comprises a paper feeding / conveying mechanism 2, a plurality of image forming unit sections 3, and a fixing device 4. The paper feeding / conveying mechanism 2 uses the paper P
It is composed of a paper feed cassette 5 and a paper transport system 6 in which the sheets are stacked and stored. Further, the paper transport system 6 supplies a paper feed roller 8 for carrying out the paper P from the paper feed cassette 5, a paper transport path 7 for carrying the paper P carried out by the paper feed roller 8, and a paper position in conformity with the toner image. Standby roll 9 for feeding
It is composed of drive rolls 10 and 11 for driving the transport belt 12, transport guide plates 14, transport rolls 15 and 16, a paper discharge guide 17, and a paper discharge roll 18.

By rotating the paper feed roller 8, the paper feed cassette 5
The paper P carried out from the paper is sent to the standby roll 9 through the paper carrying path 7 and carried out on the carrying belt 12 at the timing coincident with the toner image formed on the photosensitive drum described later. While the paper P moves on the conveyor belt 12, the paper P on the conveyor belt 12 has the image forming units 21,
The toner images are transferred from 22, 23, and 24, and the transfer process to the paper P is performed. After that, a heat fixing process is performed by the fixing device 4, the paper is sent to the paper discharge guide 17 by the transport rolls 15 and 16, and is discharged to the outside of the machine by the paper discharge roll 18.

The fixing device 4 is composed of a heat roll 4a and a pressure contact roll 4b. While the paper P is nipped and conveyed between the heat roll 4a and the pressure contact roll 4b, for example, toners of a plurality of colors transferred onto the paper P are conveyed. The image is melted and printed on the paper P.

On the other hand, the image forming unit section 3, as described above, includes yellow (Y), magenta (M), cyan (C),
Four image forming units 21 to 24 of black (BK)
And are arranged in this order. Further, the three image forming units 21 to 23 are units that transfer toner of each color of yellow (Y), magenta (M), and cyan (C) onto the paper P and perform color printing by subtractive color mixing, and are black. The (BK) image forming unit 24 is a unit used for monochrome printing.

Each of the image forming units 21 to 24 has the same structure except for the developer (color) stored in the developing container, and a charger, a print head,
The developing device and the transferring device are arranged in this order. Where 4
As a representative of the individual image forming units 21 to 24, the configuration will be described with an example of the image forming unit 23 for cyan. The peripheral surface of the photosensitive drum 25 is made of, for example, an organic photoconductive material, and a charger 26,
A print head 27, a developing device 28, and a transfer roll 29 are sequentially arranged. The photosensitive drum 25 rotates in the direction of the arrow,
First, by applying an electric charge from the charger 26, the photosensitive drum 2
The peripheral surface of 5 is uniformly charged. Next, the photosensitive drum 25 is subjected to optical writing from the print head 26 based on print information.
An electrostatic latent image is formed on the peripheral surface of, and a toner image is formed by the development processing by the developing device 28. At this time, the photosensitive drum 25
The toner image formed on the peripheral surface of the toner is cyan (C) color toner stored in the developing container 28. The toner image thus formed on the peripheral surface of the photoconductor drum 25 reaches the position of the transfer roll 29 as the photoconductor drum 25 rotates in the direction of the arrow, and is transported by the transfer roll 29 on the transport belt 12. It is transferred to the paper P to be printed.

The toner image transferred to the upper surface of the paper P is conveyed in the direction of the arrow along with the movement of the conveyor belt 12, and is formed on the paper P by the other image forming units 21 and 22 having the same structure as described above. Yellow (Y) color toner,
The toner of magenta (M) color is heat-fixed by the fixing device 4, and color printing by subtractive color mixing is performed. For example, if the print image is blue, magenta (M) color toner is transferred from the image forming unit 22 to the paper P based on the principle of subtractive color mixing, and then cyan (C) color toner is supplied from the image forming unit 23 to the paper. Transfer to P and realize a blue image. Further, for example, if the printed image is red, after transferring the yellow (Y) color toner from the developing unit 21 to the paper P, the magenta (M) color toner is transferred from the image forming unit 22 to the paper P, Realize a red image.

FIG. 2 shows a control circuit of the image forming apparatus 1 having the above-mentioned mechanical structure. The control circuit of the image forming apparatus 1 includes an interface controller 30 and a printer controller 31 connected to the interface controller 30.
The host computer 20 is connected to the interface controller 30, and each mechanical unit in the image forming apparatus 1 is connected to the printer controller 31. For example, the printer controller 31 transfers yellow (Y), magenta (M), cyan (C), and black (BK) color toners arranged in the image forming units 21 to 24 to the corresponding photoconductor drums. Print head 27 for
It is connected to Y, 27M, 27C, and 27BK. still,
The print head 27Y is a print head provided in the yellow (Y) color image forming unit 21, and the print head 27M is a print head provided in the magenta (M) color image forming unit 22. Print head 27C, 27
BK is a print head provided in each of the cyan (C) color and black (BK) image forming units 23 and 24.

The printer controller 31 is also connected to a high voltage power supply 32, various paper detection sensors 33, and a fan 34. The high-voltage power supply 32 described above is a power supply for applying a high voltage to the charger 26 and the transfer roll 29, and the various paper detection sensors 33 are sensors that detect passage of the paper P disposed in the paper conveyance path. The fan 34 is a device that exhausts and cools the air in the device. A power supply 36 is connected to the heat roll 4a of the fixing device 4 via a temperature control circuit 35, and the heat roll 4a is controlled to a predetermined temperature in accordance with a heater on / off signal output from the printer controller 31.

Power is also supplied from the power supply 36 to various drive parts 37 such as a motor and a clutch, and the drive is controlled according to a control signal output from the printer controller 31. The various driving parts 37 constitute the above-mentioned conveyor belt 12, a belt unit 38 constituting the drive rolls 10 and 11, a toner set / drum set 39 constituting each of the image forming units 21 to 24, and a sheet P conveyance system. A paper path system 40 is included and controls each drive unit in accordance with a control signal output from the printer controller 31. still,
The power supply 36 is provided with a power switch 42 having an electromagnetic reset function.

FIG. 3 shows the printer controller 31 described above.
It is a figure explaining in detail the specific circuit of power supply 36 and power supply 36, and the connection relation of both circuits. In the figure, a power supply 36 is a power supply circuit 41 and the above-described power supply switch 4 with an electromagnetic reset function.
2, which rectifies and transforms electric power supplied from a commercial power supply (AC 100 V) and supplies the electric power to each unit of the image forming apparatus 1.
In addition, the power switch 42 with the electromagnetic reset function described above.
Is composed of switches 43, 44 and a solenoid 45,
The switch 43 includes terminals 43a and 43b, and the switch 4
4 includes terminals 44a and 44b. Then, the solenoid 45 is driven according to a control signal (described later) output from the printer controller 31, and the switches 43 and 44 are turned on and off.

On the other hand, the printer controller 31 is a CPU
46, an inverter 47, resistors R1 and R2, a transistor 48, and a motor driver 49. The output port P1 of the CPU 46 outputs a control signal for driving the power switch 42 with the electromagnetic reset function. When the CPU 46 outputs, for example, a low signal, the transistor 48 is turned on and a current flows through the transistor 48. . That is, at this time, the power supply circuit 41 → solenoid 45 →
Current flows in the circuit composed of transistor 48 → ground,
The solenoid 45 is driven.

FIG. 4 is an explanatory view of the solenoid 45 arranged in the power switch 42 having the electromagnetic reset function. As shown in the figure, the solenoid 45 includes a dielectric 45b around which a coil 45a is wound and a permanent magnet 45c.
A spring 45d is interposed between the 5b and the permanent magnet 45c. Further, the permanent magnet 45c is configured to be rotatable about the fulcrum 45c 'by a predetermined angle, and the part b shown in the figure is an N pole. When the coil 45a is not excited, that is, when no current flows through the coil 45a of the solenoid 45, the c portion of the dielectric 45b is not excited, so that the contact b'of the permanent magnet 45c and the contact c'of the dielectric 45b are Separated (off).

In this state, when the permanent magnet 45c is pressed down manually (manually), the permanent magnet 45c rotates in the direction of the arrow around the fulcrum 45c ', and the permanent magnet 45c is rotated.
The portion b in FIG. 3 is an N pole, and the portion c (S pole) of the dielectric 45b is excited, and the magnetic force joins the dielectric 45b and the permanent magnet 45c (turns on).

On the other hand, when the coil 45a is excited, that is, when a current is applied to the coil 45a of the solenoid 45, the c portion of the dielectric 45b is excited to the N pole, and the contact point b'of the permanent magnet 45c and the contact point of the dielectric 45b. c'leaves (is off). That is, when the transistor 48 is turned on by the output signal from the CPU 46, a current flows through the coil 45a of the solenoid 45, and the c portion of the dielectric 45b becomes the N pole. Therefore, between the N pole of the b portion on the permanent magnet 45c side. The repulsive force acts on the dielectric 45b and the permanent magnet 45c as shown in FIG.
The contacts 4 of the switches 42 and 43 are separated by this drive.
3a and 43b, 44a and 44b are separated, and the power switch 42 with the electromagnetic reset function is turned off. That is, power supply 3
Stop supplying commercial power to 6.

On the other hand, returning to the description of FIG. 3, the belt unit 38 is connected to the motor driver 49 via a belt control motor 49 '. The belt unit 38 drives the above-mentioned drive roll 10 up and down, and the conveyor belt 12
Is set to the position of the color print mode or the monochrome print mode. This control is performed according to a control signal output from the output port P2 of the CPU 46.

Next, the operation of the image forming apparatus 1 having the above configuration will be described with reference to the flowchart shown in FIG. First, the CPU 46 in the printer controller 31 determines whether a print start command has been received (step (hereinafter S
TP) 1). This determination is made by, for example, the operator pressing a print instruction key (not shown) provided in the image forming apparatus 1, and this signal is transmitted to the interface controller 3
It is input to the CPU 46 via 0, and it is determined that the print start command is input. Therefore, the CPU 46 waits until the print start command is input. When the print start command is input (STP1 is Y), the CPU 46 next determines whether or not a color print command is issued (STP2).

This judgment by the CPU 46 is, for example, CP
It is a print mode input to U46, and is often a print mode that is frequently used. For example, if this mode is a color printing mode, it is necessary that the above-mentioned conveyor belt 12 is raised (STP3 is Y), and the printing operation can be executed immediately (STP4). In this embodiment, this probability is high because the color printing mode that is frequently used is initially set.

After that, when the above-mentioned print processing is completed, standby operation processing is performed (STP5), and the input of the next print start command is waited (STP1). After that, if there is a monochrome print instruction along with the input of a print start command (STP1
Is Y, STP2 is N), and the CPU 46 determines whether the conveyor belt 12 is set for monochrome printing (STP).
6). At this time, in the above described example, the printing mode of the apparatus is set to the color printing mode, so the CPU 46 outputs a control signal to the motor driver 49 to drive the belt unit 38 and move the conveyor belt 12 downward. (ST
P7). By this processing, the image forming apparatus 1 is set to the monochrome print mode, and thereafter the print operation is executed (ST
P8), the standby operation process is performed (STP9), and the input of the next print start command is awaited (STP1). When the color printing is instructed again (STP3 is Y), the conveyor belt 12
To the color print mode again (STP
3, STP10, STP4).

While the above process is repeated, the CPU 46 determines that the power off command is received, and repeats the above process while the power off command is not input (STP11 is N). on the other hand,
When the power-off command is received (STP11 is Y), the flowchart shown in FIG. 6 is executed. That is, it is determined whether the current color printing mode is set (STP12), and if it is the color printing mode, the power switch is turned off and electromagnetic reset drive is executed (STP12 is Y, STP13).
On the other hand, in the monochrome print mode (N in STP12), the motor driver 49 is driven to move the conveyor belt 12 upward, and then the power switch is turned off to execute the power reset drive (STP14, STP13).

By performing the above processing, the conveyor belt 12 is always set in the color printing mode when the power of the image forming apparatus 1 is turned off. Therefore, when the power of the image forming apparatus 1 is turned on again to perform the print processing by the above-described processing, the color print mode is always set and the transport belt 12 is set to the upper side (STP3 is Y).
Therefore, the print process can be started immediately after the power supply to the image forming apparatus 1 is turned on, and the print process can be efficiently performed.

Next, a second embodiment of the present invention will be described. This example is the same in structure as FIG. 1 used in the description of the above-described embodiment, but the control method is different. FIG. 7 is a flow chart showing the explanation of the operation of this example. Also in the case of this example, when the CPU 46 receives the print start command (step (hereinafter, V) 1 is Y), it is determined whether or not the color printing is instructed (V2) and the color printing is instructed similarly to the above-described embodiment. If so, the position of the conveyor belt 12 is determined (V
3), if the conveyor belt 12 is at the upper position, the printing operation is immediately executed (V3 is Y, V4), and the conveyor belt 12 is
Is not at the upper position, the printing operation is performed after moving the conveyor belt 12 upward (V3 is N, V5, V
4). On the other hand, even in the monochrome printing mode, the position of the conveyor belt 12 is judged (V6), and if the conveyor belt 12 is at the lower position, the printing operation is immediately executed (V6 is Y, V7), and the conveyor belt 12 is If it is not located at the lower position, the printing operation is executed after moving the conveyor belt 12 downward (V6 is N, V8, V7).

After the above processing, the standby operation processing is performed (V
(9, V10), the CPU 46 waits for the next print start command (V1) and determines whether the power-off command is input (V11).

After that, the CPU 46 judges whether the state in which the print start command and the power off command are not input continues for, for example, 10 minutes (V12), and when this period continues for 10 minutes or more (V12 is Y), the apparatus performs color printing. It is determined whether the mode is set (V13), and if it is not the color printing mode, the conveyor belt 12 is moved upward to change to the color printing mode (V14).

By performing the processing as described above, the color print mode is always set when the image forming apparatus 1 is not turned on for a certain period of time when the power is on, and when the print processing is performed thereafter, the color print mode is set. Start (V
1, V2) and the conveyor belt 12 are surely set to the upper side, so that the printing process can be started immediately (V3, V4).

Returning to the explanation of FIG. 7, when the power-off command is input while waiting for the print start command and the power-off command (V11 is Y), the process shown in FIG. 8 is executed. That is, similarly to the example of the above-described embodiment, it is determined whether the current print mode is the color print mode (V15), and if it is the color print mode, the power switch is turned off and reset drive is executed (V15 is Y, V16. ). On the other hand, in the monochrome printing mode (V15 is N), the motor driver 49 is driven to move the conveyor belt 12 upward, and then the reset drive is executed to turn off the power switch (V
17, V16).

Next, an example of the third embodiment of the present invention will be described. Also in the case of this example, the configuration is the same as the examples of the above-described two embodiments, and the control method is different. FIG. 9 is a flowchart showing the operation description of this example. First, CP
When U46 receives the print start command (step (hereinafter U) 1 is Y), it is judged whether or not it is a color printing instruction (U2). If it is a color printing instruction, the position of the conveyor belt 12 is judged ( U3), if the conveyor belt 12 is at the upper position, the printing operation is immediately executed (U3 is Y, U
4) If the conveyor belt 12 is not at the upper position, the conveyor belt 12 is moved upward and then the printing operation is executed (U3 is Y, U5, U4).

Thereafter, it is judged whether or not a paper jam occurs during the print processing (U6), and if the print processing ends without the paper jam occurring, the standby processing is performed (U).
7). On the other hand, if a paper jam occurs during the above-described print processing (Y in U6), the flowchart shown in FIG. 10 is executed.

That is, since the color printing mode is currently set, the conveyor belt 12 is positioned above. Therefore, CP
U46 controls the motor driver 49 to convey the conveyor belt 12
Is moved downward (U8). After this processing, the CPU 46
Determines whether the roof of the image forming apparatus 1 is opened in order to pull out the jammed paper P. If the roof is opened (U9 is Y), it can be determined that the roof is opened to remove the paper P, and the color printing mode is set thereafter.
That is, the previous state is judged (U10), and since the color printing mode was selected (U10 is Y), the conveyor belt 12 is again detected.
To move up (U11) and continue the printing process (U
7).

On the other hand, in the above-mentioned judgment (U2), for example, when the color printing is not instructed (U2 is N), the position of the conveyor belt 12 is judged (U12), and if the conveyor belt 12 is at the lower position, it is immediately printed. Execute the operation (U12
Is Y, U13), and if the conveyor belt 12 is not at the lower position, the conveyor belt 12 is moved downward, and then the printing operation is executed (U12 is Y, U14, U13).

Even during this print processing, it is judged whether or not a paper jam occurs (U15), and if the print processing ends without a paper jam, a standby processing is performed (U16). On the other hand, if a paper jam occurs during the above print processing (Y in U15), the process proceeds to the determination (U9) in the flowchart shown in FIG.
Determines that the roof of the image forming apparatus 1 has been opened in order to pull out the jammed paper P as described above. Here, if the roof is opened (U9 is Y), it can be determined that the roof is opened to remove the paper P as described above, and it is determined whether it is the color print mode (U10). In this case, the monochrome print mode is set. Therefore (N in U10), the print end process and the standby process shown in FIG. 9 are executed as they are (U16).

With this control, even when a paper jam occurs, color printing or monochrome printing can be executed immediately after the end of the processing. After that, while repeating the above-described processing, the CPU 46 determines that the power-off command is received, and while the power-off command is not input (U17 is N),
When the power-off command is received after repeating the above-described processing (Y in U17), the flowchart shown in FIG. 11 is executed. That is, as described in the examples of the above two embodiments, it is determined whether the current color printing mode is set (U18), and if it is the color printing mode, the power switch is turned off and the reset drive is executed (Y, U19 for U18). ).
On the other hand, in the monochrome print mode (N in U18), the motor driver 49 is driven to move the conveyor belt 12 upward, and then the power switch is turned off to execute the reset drive (U20, U19).

Next, an example of the fourth embodiment of the present invention will be described. FIG. 12 is a flowchart showing the processing operation of this example. First, it is judged whether or not a power-off command is received (step (hereinafter W) 1), and when the power-off command is not received (W1 is N), normal operation processing of the image forming apparatus 1 is performed (W2). On the other hand, when the power-off command is received during the above-described normal processing (W1 is Y), it is determined whether the current state of the image forming apparatus 1 is print processing (W3). At this time, for example, if the print process is in progress (W3 is Y), the process waits until the print process is completed, and the next determination (W4) is performed to determine whether or not it is in the idle state. If the above determination is not in the printing process (W3 is N), it is immediately determined whether it is in the idle state (W4). The idle state is a state in which power is not supplied to the heat roll 4a of the fixing device 4 such as a sleep mode, and is a so-called power saving mode.

When the apparatus is in this idle state, the CPU 46 stops the power supply to the heat roll 4a (W4 is Y, W
5), stopping the power supply to the heat roll 4a. afterwards,
The CPU 46 resets the power switch (W
6).

In the reset process of the power switch, the CPU 46 outputs a high signal to the transistor, drives the solenoid 45, and turns off the power switch 42 having the electromagnetic reset function. When the power switch 42 with the electromagnetic reset function is turned off, the power supply to the image forming apparatus 1 is stopped. That is, in the example of the present embodiment, the heat roll 4a is turned off at this time, no arc is generated when the power switch 42 is turned off, and the contacts of the power switch with the electromagnetic reset function are not damaged.

After the power switch is reset, it is judged whether the power is turned off (W7). If the power is off, the process is terminated (W7 is Y). However, when the power does not turn off (W7
N), the reset process of the power switch is repeated n times (W8), and if the power is not turned off even after the reset process is repeated n times, an alarm is sounded (W9 → W7 → W).
8 → W10).

In the description of the above embodiment, the heat roll 4 is used.
Although the power switch 42 is cut off after turning off a,
Not only the heat roll 4a but also another device having large power consumption may be turned off in advance and then the power switch may be cut off.

[0056]

As described above, according to the present invention, the image forming apparatus is always set in the print mode which is frequently used when the power is shut off. Print processing can be performed with.

Further, when the power is shut off, the power supply to the large current load is always stopped first, and then the power of the image forming apparatus is shut off, so that the power switch is deteriorated and the occurrence of insulation failure can be prevented.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an image forming apparatus illustrating an example of a first embodiment.

FIG. 2 is a diagram showing a control circuit of the image forming apparatus having the above-mentioned mechanical structure.

FIG. 3 is a specific circuit of a printer controller and a power supply,
3A and 3B are diagrams illustrating a connection relationship between both circuits.

FIG. 4 is a drive explanatory diagram of a solenoid provided in a power switch having an electromagnetic reset function.

FIG. 5 is a flowchart illustrating an operation example of the first embodiment.

FIG. 6 is a flowchart illustrating an operation example of the first embodiment.

FIG. 7 is a flowchart illustrating a processing operation of the image forming apparatus according to the second exemplary embodiment.

FIG. 8 is a flowchart illustrating a processing operation of the image forming apparatus according to the second embodiment.

FIG. 9 is a flowchart illustrating a processing operation of the image forming apparatus according to the third exemplary embodiment.

FIG. 10 is a flowchart illustrating a processing operation of the image forming apparatus according to the third exemplary embodiment.

FIG. 11 is a flowchart illustrating a processing operation of the image forming apparatus according to the third exemplary embodiment.

FIG. 12 is a flowchart illustrating a processing operation of the image forming apparatus according to the fourth exemplary embodiment.

FIG. 13 is a diagram illustrating an overall configuration of a conventional image forming apparatus.

FIG. 14 is a flowchart illustrating a processing operation of a conventional image forming apparatus.

FIG. 15 is a flowchart illustrating a processing operation of a conventional image forming apparatus.

[Explanation of symbols]

 1 Image Forming Apparatus 2 Paper Supply / Conveying Mechanism 3 Image Forming Unit 4 Fixing Device 4a Heat Roll 4b Pressing Roll 5 Paper Feeding Cassette 6 Paper Conveying System 7 Paper Conveying Path 8 Conveying Roller 9 Standby Roll 10, 11 Driving Roll 12 Conveying Belt 14 Conveyance guide plates 15 and 16 Conveyance rolls 17 Discharge guides 18 Discharge rolls 21 to 24 Image forming unit 25 Photoreceptor drum 26 Charger 27 Print head 28 Developer 29 Transfer roll 30 Interface controller 31 Printer controller 32 High voltage power supply 33 Paper detection Various sensors 34 Fan 36 Power supply 37 Various drive parts 38 Belt unit 39 Toner set / Drum set 40 Paper path system 41 Power supply circuit 42 Power switch with electromagnetic reset function 43, 44 Switch 43a, 43b, 44a, 44b Terminal 45 Solenoid 46 CPU 47 Inverter 48 Transistor 49 Motor driver

Claims (7)

[Claims] 1. In an image forming apparatus having a plurality of image forming processing modes, a mode identifying means for identifying an operation mode of the image forming processing, an identifying means for identifying execution of a power shutoff process, and the identifying means for shutting off power. When the process is identified, if the device is in a processing mode that is used less frequently before the power to the device is shut down, the power is shut off after changing the state to the process mode that is used frequently. An image forming apparatus comprising: a power-off process control unit that executes the power-off process. 2. The processing mode having a high frequency of use is a color printing mode, and the processing mode having a low frequency of use is a monochrome printing mode.
The image forming apparatus as described in the above. 3. A color image forming apparatus having a color image forming processing mode and a single color image forming processing mode, wherein after a period in which no print processing is performed for a predetermined time or more continues, return control to the initialization print mode is performed. And a color image forming apparatus. 4. A color image forming apparatus having a color image forming processing mode and a monochromatic image forming processing mode, further comprising a power saving control means for shifting to a power saving control mode after a period in which printing processing is not performed for a predetermined time or more continues. At the same time, the power saving control means controls the initialization printing means to return to the power saving state before switching to the power saving state. 5. The color image forming apparatus according to claim 4, wherein the initialization print mode is a color image forming processing mode. 6. The color image forming apparatus according to claim 4, wherein the initialization print mode is a single color image forming processing mode. 7. An image forming apparatus, comprising a power supply control means for a large current load, and a self power shutoff device for shutting off the power of the device according to a command from a remote device, wherein the self power shutoff device is a power shutoff command. When receiving, the image forming apparatus causes the power supply control unit to perform control for prohibiting supply of power to the large current load prior to execution of the power cutoff process.