JPH0999585A - Image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformize the driving time of respective electrical parts without starting a specified electrical part only at all times by starting respective electrical parts in the starting order based on the continuous driving time all through from the starting time to stopping time of respective electrical parts when a plurality of electrical parts into which a rush current is flowed at the starting time are started. SOLUTION: In case of starting first drum motors 361-364 after a power source is on or first after the replacement of a printing station, the drum motors are started in the order of 361-364. At that time, the count of respective timers 33a is started together with the start of respective drum motors 361-364, and the time until respective stopping time is stored in an EEPROM 34. After that, when the given printing process is completed, respective drum motors 361-364 are stopped simultaneously. In the case of starting the motors afterwards, the motors are started in the order based on respective timer count values at the start of drum motors 361-364 in the last operation, namely the motors are started in the order from shorter to longer continuous driving times of respective drum motors 361-364.

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 that drives a plurality of electric parts into which an inrush current flows at the time of startup to form an image.

[0002]

2. Description of the Related Art Generally, an image forming apparatus is provided with a plurality of electric parts into which an inrush current flows at the time of starting, and performs an image forming process while starting these parts at a predetermined timing. Examples of such an image forming apparatus include a copying machine, a laser printer, a color laser printer, and the like. In this color laser printer, four printing stations of yellow (Y), magenta (M), cyan (C), and black (K) are continuously arranged on an endless belt-shaped paper conveyance belt stretched inside the main body of the apparatus. Configured.

Each printing station is provided with an electrophotographic process mechanism in which a charging device, an exposing device and a developing device are arranged around a photosensitive drum. The photosensitive drum is an electric part into which a rush current flows when starting up. Drum motors for driving the motors. Stepping motors are usually used as these motors.

In such a color laser printer, when printing is performed, images are transferred from the printing stations to the recording paper conveyed by the paper conveyance belt to superimpose the respective colors to perform color printing.

Therefore, when the printing process is started, first, it is necessary to drive the conveyor belt so that the recording paper can be conveyed, and at the same time, the drum motor is started so that each printing station is ready to print. At this time, if the respective drum motors are started at the same time, there is a problem that the inrush current generated at that time becomes large and a power source having a large current capacity is required.

Therefore, conventionally, when the printing is started, the drum motor of the yellow (Y) printing station is first started, and when the motor reaches a steady rotation, the drum motor of the magenta (M) printing station is started. When this drum motor reaches steady rotation, the drum motor of the cyan (C) printing station is started, and when this motor reaches steady rotation, black (K)
Had to start the drum motor of the printing station. After that, when the predetermined printing process is completed and the drum motors are stopped, the respective drum motors are simultaneously stopped in order to avoid unnecessary rotation of the motors.

[0007]

However, in such a case, there is a problem that the time until the next drum motor is started becomes long and the time required for printing the first page becomes too long. Further, since the motors are always started in the same order, the drive time differs depending on each drum motor, and therefore the motor that starts first has a longer continuous drive time. For this reason, the life of a specific printing station becomes shorter than that of other printing stations due to wear of the photosensitive drum due to contact friction with the paper transport belt and developing roller. However, if they are set separately, there is a problem that only the specific printing station reaches the replacement time earlier and the replacement frequency increases.

Further, for example, if it is attempted to set the replacement time by the number of printed sheets or the like in all the printing stations, the number of printing sheets at the time of replacement is set in accordance with the printing station that is first started, which takes the longest driving time. Therefore, there is also a problem that the life of the entire device is shortened.

Therefore, according to the present invention, it is possible to make the lives of a plurality of electric parts into which the inrush current flows at the time of start-up uniform,
Accordingly, it is an object of the present invention to provide an image forming apparatus capable of extending the life of the apparatus as a whole, reducing the number of times the printing station needs to be replaced, and suppressing the inrush current that occurs when the electrical components are started. .

[0010]

SUMMARY OF THE INVENTION According to the present invention, in an image forming apparatus for forming an image by activating a plurality of electric components in which a rush current flows at the time of activation, the electric component driving means for driving the electric components is provided. A clocking means for clocking the continuous drive time of each electrical component driven by the electrical component drive means from start to stop, and a drive time memory for storing the continuous drive time of each electrical component clocked by the clock means And means for activating each electric component, and activating order determining means for deciding the activation order of the electric components to be activated based on the previous continuous drive time of each electric component from the drive time storage means. It is provided.

In the present invention having such a structure, when starting a plurality of electric parts into which an inrush current flows at the time of starting,
By starting each electric component in the starting order determined based on the continuous drive time from the start to the stop of each electric component, it is possible to prevent a specific electric component from always starting first, and The driving time can be made uniform.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention applied to a color laser printer will be described below with reference to the drawings.

FIG. 1 is a sectional view showing the structure of a color laser printer according to the present embodiment. Reference numerals 21 to 24 are arranged continuously on an endless belt-shaped sheet conveying belt 1 stretched inside the main body of the apparatus. Individual printing stations.

In each of the printing stations 21 to 24, a charging device 4, an exposure device 5, a developing device 6, a drum cleaner 7 and a charge eliminating lamp 8 are arranged around the photosensitive drum 3 so as to face each other, and the photosensitive drum 3 is provided with a sheet conveying belt 1. The transfer roller 9 is disposed so as to be opposed to each other.

The developing device 6 of each of the printing stations 21 to 24 stores yellow (Y), magenta (M), cyan (C), and black (K) toners, and the developing roller 10 is rotatably provided at the bottom. The toner is supplied to the photosensitive drum 3 by the contact charging.

A belt charger 11 is arranged at a conveyance start position of the sheet conveying belt 1, and a tension roller 12 for giving a predetermined tension to the sheet conveying belt 1 is arranged. The sheet conveying belt 1 is made of a conductive material, and its surface is covered with an insulating layer. The conductive material is wound around the pair of guide rollers 14 and 15 so as to come into contact with each other.

Below the paper transport belt 1, a paper feeding device 19 in which recording papers 18 are stacked and stored is detachably provided. A paper feed roller 23 for picking up the recording paper 18, a transport roller 24 for guiding the recording paper 18 to the transport path 13, and the like are provided above the paper feeder 19.

A conveyance path 13 for guiding the recording paper 18 from the paper feeding device 19 to the end of the paper conveyance belt 1 is provided near one guide roller 14. Further, the fixing device 20 is arranged close to the outside of the other guide roller 15.

In this apparatus, a recording sheet 18 fed from a sheet feeding device 19 is fed by a belt charger 11 to the sheet conveying belt 1.
After adsorbing to, the printing station 21 transfers a yellow image, the printing station 22 transfers a magenta image, and the printing station 23 transfers a cyan image to perform color printing by superimposing colors.
The fixing device 20 thermally fixes and discharges the sheet to the sheet discharge unit 21 or 22.

FIG. 2 is a block diagram showing the circuit configuration of the control unit of the color laser printer shown in FIG. 1. Reference numeral 31 is a CPU (central processing unit) that constitutes the control unit main body, and 32 is this C.
A ROM (read only memory) storing program data and the like for the PU 31 to control each unit, 33 is provided with a memory and the like used for data processing, and timekeeping for counting the drive time of the drum motor described later. A timer 33a as a means is provided for each printing station 21 ...
A RAM (random access memory) provided for each 24, EEP as a drive time storage means for storing the count value of the motor drive time by the timer 33a
(Electrically Erasable Programmable) ROM.

Further, 351 is a motor drive circuit as an electric component driving means for driving the drum motor 361 of the yellow (Y) printing station 21, and 352 is an electric circuit for driving the drum motor 362 of the magenta (M) printing station 22. Motor drive circuit as component drive means, 3
Numeral 53 designates a motor driving circuit as an electric component driving means for driving the drum motor 363 of the cyan (C) printing station 23, and 354 designates an electric component driving means for driving the drum motor 364 of the black (K) printing station 24. It is a motor drive circuit. These motors 361-
Reference numeral 364 is an electric component into which an inrush current flows at the time of starting.
CPU 31, ROM 32, RAM 33, EEPRO
The bus line 37 electrically connects the M34 and the motor drive circuits 351 to 354.

Although not shown in FIG. 2, the CPU 31 has a polygonal motor provided on a belt motor for driving the sheet conveying belt 1 and a developing motor / exposure device 5 for driving the developing roller 10 of each of the printing stations 21 to 24. A fixing device 20 such as a motor, various sensors such as a sensor for detecting a jam of the recording paper 18, and an I / F (interface) to which a host computer is connected via a communication line are connected.

The CPU 31 is adapted to perform motor drive control as shown in FIG. 4 when performing printing. That is, it is determined in ST (step) 1 whether or not there is an instruction to start the printing process. When it is determined that the print processing start instruction has been given, whether or not it is the first print processing in ST2, that is, whether or not it is the first print processing after the printer device is first powered on, It is determined whether or not it is the first printing process after the stations 21 to 24 are exchanged.

At this time, if it is determined that the printing process is the first one, the drum motors 361 to 36 in ST3.
Initialize the sequence in which 4 is started. That is, first the drum motor 361 is the first and the drum motor 362 is the second.
Th, drum motor 363 is third, drum motor 36
Set 4 to 4 and move to the processing of ST4.

That is, the first set drum motor is started in ST4, and the timer 33a corresponding to the drum motor is started to count in ST5.
Subsequently, after a lapse of a predetermined time from the start of the first set drum motor in ST6, the second set drum motor is started, and in ST7, the timer 33a corresponding to the drum motor is started to count.

Next, after a predetermined time has elapsed from the start of the second drum motor set in ST8, the third set drum motor is started, and in ST9 the timer 33a corresponding to the drum motor is counted. Start. Further, after a predetermined time has elapsed from the start of the third drum motor set in ST10, the fourth drum motor is started, and in ST11 the timer 33a corresponding to the drum motor is started to count.

The time until the next motor is started after the motor is started may be a preset time or may be after the motor which is started immediately before reaches the steady rotation.

Then, in ST12, it is determined whether or not the printing process is completed. When it is determined that the printing process is completed, all the drum motors are stopped at the same time in ST13, and all the timers 33 are stopped in ST14.
The count of a is stopped, the timer count value at that time is stored in the EEPROM 34, and this motor control process is ended.

On the other hand, if it is determined in ST2 that the printing process is not the first one, in ST15 the EEPROM
From 34, the timer count value corresponding to each drum motor stored in the previous motor drive processing is read. Then, ST
In step 16, the start order of the drum motors is set in the ascending order of the timer count values corresponding to the drum motors stored in the EEPROM 34 in the previous motor drive processing, that is, in the order in which the last continuously driven time is short. (Order determining means), the process proceeds to ST4 and subsequent steps, and the drum motor is started in this set order.

In the embodiment of the present invention having such a structure, the drum motor 3 is firstly turned on after the first power-on.
61-364 or when starting the printing station 21-
When the drum motors 361 to 364 are first started after the replacement of the 24, the drum motor 361
Start these in the order of ~ 364. At this time, when the drum motors 361 to 364 are started, the timer 33a starts counting and stops until the EEPR is reached.
Store in OM34. After that, when the predetermined printing process such as the conveyance of the recording paper and the transfer from each printing station is completed, the drum motors 361 to 364 are stopped at the same time.

When the motor is started after this, each timer count value when the drum motors 361 to 364 were started last time, that is, the drum motors 361 to 364 are started.
The motors are started in the ascending order of 364 continuous driving times.
For example, as shown in FIG. 3, the previous continuous driving time of the drum motors 361 to 364 is T1 to T4 (T1>
If T2>T3> T4), the drum motor 36
Start in the order of 4, 363, 362, 361.

Also at this time, each drum motor 3
The time from the start of counting of each timer 33a with the start of 61 to 364 to the stop thereof is determined by the EEPROM 34.
To memorize. After that, when the predetermined printing process such as the conveyance of the recording paper and the transfer from each printing station is completed, the drum motors 361 to 364 are stopped at the same time.

In this way, the previous drum motors 361
Since the continuous driving times of ˜364 are counted and the drum motors 361 to 364 are started in the ascending order of the continuous driving time at the next motor start, it is possible to eliminate variations in the driving time of each motor. As a result, it is possible to prevent the abrasion of the photosensitive drum and the like from being concentrated on a specific printing station, and it is possible to make the life of each printing station uniform. Therefore, the life of the entire apparatus can be extended and the number of times the printing station is replaced can be reduced.

Further, the continuous drive time of each drum motor 361 to 364 (timer count value of the timer 33a) can be written, and the stored contents are not erased even if a power failure occurs.
Since it is stored in the ROM 34, the continuous drive time of each drum motor 361 to 364 can be retained without being erased even when the power of the apparatus is turned off. As a result, the lifespan of the printing stations 21 to 24 can be more surely made uniform.

In the embodiment of the present invention, the case where each of the drum motors 361 to 364 as a plurality of electric parts into which the inrush current flows at the time of starting is the stepping motor has been described, but the invention is not limited thereto. Instead of the above, a DC motor may be used as a plurality of electric parts into which an inrush current flows at the time of startup.

Further, in the embodiment of the present invention, the case where the drum motors 361 to 364 are started as a plurality of electric parts into which an inrush current flows at the time of starting is described, but the present invention is not necessarily limited to this. It may be applied to a belt motor that drives the sheet conveyance belt 1, a motor that drives the developing roller of the developing device 6, a power supply circuit, a switch circuit of the discharge lamp 8 and the like as a plurality of electric components into which a rush current sometimes flows.

Further, in the embodiment of the present invention,
The previous description has been made on the case of starting each of the drum motors 361 to 364 in ascending order of continuous driving time, but the invention is not limited to this, and each of the drum motors 361 to 364 counted by the timer 33a is not limited to this. It is also possible to accumulate the continuous drive times of the above and start the drum motors 361 to 364 in the ascending order of the accumulated drive times. As a result, each drum motor 361-3
The above effect can be effectively achieved even when the difference in continuous driving time of 64 is small.

[0038]

As described in detail above, according to the present invention, it is possible to make the lives of a plurality of electric parts into which an inrush current flows at the time of start-up uniform, and thereby to extend the life of the entire device and to perform printing. It is possible to provide an image forming apparatus that can reduce the number of station replacements and can suppress an inrush current that occurs when an electric component is activated.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a main configuration of an embodiment of the present invention.

FIG. 2 is a block diagram showing a main configuration of a circuit of the color laser printer shown in FIG.

FIG. 3 is a diagram showing control timing in motor control performed by the CPU shown in FIG.

4 is a flowchart showing motor drive control performed by the CPU shown in FIG.

[Explanation of symbols]

31 ... CPU (starting order determining means) 34 ... EEPROM (driving time storing means) 33a ... Timer (time measuring means) 351 to 354 ... Motor driving circuit (electrical component driving means) 361 to 364 ... Drum motor (plurality into which inrush current flows) Electrical components)

Claims (1)

[Claims] 1. An image forming apparatus for forming an image by activating a plurality of electric parts in which a rush current flows at the time of start-up by staggering the time, and an electric part driving means for driving the electric parts, and the electric part driving means. A clocking means for respectively clocking the continuous drive time from the start to the stop of each of the driven electrical parts, and a drive time storage means for storing the continuous drive time of each of the electrical components clocked by this clock means,
When activating each of the electric components, there is provided a activating order determining unit that determines the activating sequence of the electric components to be activated based on the previous continuous drive time of each of the electric components from the drive time storing unit. An image forming apparatus characterized by being provided.