JPH1191204A - Electronic photograph printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the requirement of employing a driving means having a driving torque bigger than a required value by a method wherein a driving torque changing means, increasing a driving torque, generated by a driving means for rotating the rollers of a printed image forming means when a new printed image forming means is set, to effect idling, is provided. SOLUTION: When a switch 44 is put ON and a power supply 43 is charged, an idling command is generated from a control unit 31 and it is judged whether a toner is consumed at all or the life of the same is finished or not and a new process cartridge is set or not or a counter 47 is reset or not. When the counter 47 is reset in this case, a heater 41 is excited by a heater driving control unit 42 and warm-up of increasing the temperature of a fixing device is effected. On the other hand, an electric current, supplied to a driving motor 24 by a motor driving control unit 35, is increased much more that in usual whereby idling, increasing a generated driving torque, is effected. According to this method, toner prevails in the whole of a process cartridge soon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an electrophotographic printing apparatus.

[0002]

2. Description of the Related Art Conventionally, in an electrophotographic printing apparatus, the surface of a photosensitive drum is uniformly and uniformly charged by a charging roller, and the surface of the photosensitive drum is exposed and exposed by an exposure device such as an LED head. An electrostatic latent image is formed, and development is performed by attaching a toner charged to a negative polarity to the electrostatic latent image by a developing roller. Then, a process cartridge is formed by integrating the photosensitive drum, the charging roller, the exposure device, the developing roller, and the like.

In the process cartridge, a toner cartridge accommodating toner is removably disposed, and when the use of the process cartridge is started, the toner cartridge is set in the process cartridge. A dedicated chamber for accommodating the toner is formed integrally with the toner cartridge, and a partition for separating the dedicated chamber from other parts is removed when the process cartridge is started to be used.

By the way, after assembling a process cartridge at a factory, the process cartridge is set in a dedicated tester for operating the process cartridge, and an image output test is performed to check the quality of an image. In this case, it is only necessary to confirm the quality of the image so that the productivity is not reduced by performing the image output test.
Approximately two sheets are printed. In addition, when a toner cartridge is set in the process cartridge or the partition is removed in order to perform an image output test, when the process cartridge is transported from a factory to a user, i.e., an operator, the process cartridge can be removed. The toner may leak out and stain the case of the process cartridge. Therefore, in order to prevent extra toner from remaining in the process cartridge after the image forming test, toner for the image forming test is directly supplied to the vicinity of the developing roller.

[0005]

However, in the conventional electrophotographic printing apparatus, after the use of the process cartridge is started, the photosensitive drum, the charging roller,
As the rollers such as the developing roller rotate, the toner reaches the entire inside of the process cartridge, and the toner acts as a lubricant, so that each of the slides of the process cartridge is removed.
While the rotating load on the moving part gradually decreases,
Immediately after assembling the process cartridge or in the initial state where only the image output test is performed, only one or two sheets of printing are performed, so that the toner does not reach the entire inside of the process cartridge, Large rotating load.

For example, in the case of a process cartridge for printing on A4 size printing paper, the rotational load in the initial state is about 2.8 [kg / cm], but about 3 [kg / cm].
It was observed that the idling for about 1 minute reduced to about 2.2 [kg / cm]. Therefore, in designing the electrophotographic printing apparatus, in order to rotate the rollers of the process cartridge, it is necessary to select a drive motor as a drive unit having a drive torque more than necessary in consideration of a rotational load in an initial state. Therefore, not only does the cost increase, but also the acceleration at the time of starting the electrophotographic printing apparatus needs to be set lower accordingly, and the controllability decreases.

The present invention solves the above-mentioned problems of the conventional electrophotographic printing apparatus, so that there is no need to select a driving means having a driving torque more than necessary, the cost can be reduced, and the controllability is improved. It is an object of the present invention to provide an electrophotographic printing device capable of causing the printing.

[0008]

For this purpose, in an electrophotographic printing apparatus according to the present invention, an image forming means for performing printing by an electrophotographic process, a driving means for rotating rollers of the image forming means, and a new image forming apparatus. And a drive torque changing means for increasing the drive torque generated by the drive means when the forming means is set to perform idling.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 2 is a schematic diagram of the electrophotographic printing apparatus according to the first embodiment of the present invention. In the figure, reference numeral 12 denotes a process cartridge as an image forming means for performing printing by an electrophotographic process;
Reference numeral 3 denotes a photosensitive drum, and the surface of the photosensitive drum 13 is uniformly and uniformly charged by the charging roller 14. Further, an exposure device such as an LED head (not shown) is provided so as to face the photoconductor drum 13, and the surface of the photoconductor drum 13 is exposed by the exposure device.
An electrostatic latent image is formed.

Reference numeral 15 denotes a developing roller disposed so as to face the photosensitive drum 13. The developing roller 15 applies toner charged to a negative polarity to the electrostatic latent image by the developing roller 15. Thus, a toner image is formed. Further, a transfer roller (not shown) is provided so as to face the photoconductor drum 13, and the toner image is transferred to a printing paper (not shown) by the transfer roller. Then, the toner image transferred to the printing paper is fixed by a fixing device (not shown).

A sponge roller 18 is provided in contact with the developing roller 15, and the toner charged to a negative polarity is supplied to the developing roller 15 by the sponge roller 18.
Supplied to In order to supply the toner in the toner chamber 19 to the sponge roller 18, a stirring (stirring) bar 20 is rotatably arranged in the toner chamber 19. In order to supply toner to the toner chamber 19, a toner cartridge 21 is set above the toner chamber 19, and the toner in the toner cartridge 21 is transferred to the toner chamber 1.
9 to fall. Then, a toner layer regulating blade 22 is provided in contact with the developing roller 15, and the toner layer on the developing roller 15 is thinned by the toner layer regulating blade 22. The photosensitive drum 13, the charging roller 14, the developing roller 15, the sponge roller 18 and the like are all rotated in the direction of the arrow.

The process cartridge 12 having the above-described structure includes:
The photosensitive drum 13, the charging roller 14, the exposure device, the developing roller 15, and the like are formed by integrating them, and the toner cartridge 21 is set.
The toner in the toner cartridge 1 falls into the toner chamber 19. Then, the toner in the toner chamber 19 is stirred by the stirring bar 20 and supplied to and adhered to the sponge roller 18. Further, the toner adhering to the sponge roller 18 is supplied to the developing roller 15 with the rotation of the sponge roller 18, is thinned by the toner layer regulating blade 22 on the developing roller 15, and is supplied to the photosensitive drum 13. And attached to the electrostatic latent image.

Next, a control device of the electrophotographic printing apparatus will be described. FIG. 1 is a control block diagram of the electrophotographic printing apparatus according to the first embodiment of the present invention. In the figure, 31 is a control unit for controlling the whole of the electrophotographic printing apparatus, 32 is a ROM, and 34 is a process cartridge 12.
A drive motor 35 for driving rollers such as the photosensitive drum 13, the charging roller 14, the developing roller 15, and the sponge roller 18 shown in FIG. A motor drive controller for controlling the drive motor 34, a temperature detector 36 for detecting the temperature of a fixing unit (not shown), and a temperature 37 for detecting the temperature detected by the temperature detector 36 in response to an instruction from the controller 31 A fixing unit temperature control unit 41 for reading is built in the fixing unit, and a heater for heating a fixing roller of the fixing unit.
2 receives the instruction from the control unit 31 and
A power supply for the electrophotographic printing apparatus; 44, a switch for turning on / off the power supply 43; 45, an operation unit; 46, an EEPROM;
A counter 48 incorporated in the EPROM 46 is a toner remaining amount detecting sensor for detecting the remaining amount of toner in the toner chamber 19.

By the way, while printing is performed using the electrophotographic printing apparatus, the motor drive control unit 35
Is based on the rotation speed of the drive motor 34.
3 is rotated, and the number of rotations is counted by a counter 47.
To be stored. In this case, the set number of toner cartridges 21 can normally be used before the photosensitive drum 13 reaches the end of its life. Accordingly, of the set number of toner cartridges 21, at a predetermined timing before all the toner in the last toner cartridge 21 is consumed,
The count value of the counter 47 reaches a preset spare life value.

After the count value reaches the preliminary life value, when the toner remaining amount detecting sensor 48 detects that all the toner in the last toner cartridge 21 has been consumed, the motor drive is started. Control unit 35
Displays a message such as "Drum replacement" on a display (not shown) of the operation unit 45, and instructs the operator to replace the process cartridge 12. Therefore, the operator opens the cover (not shown) of the electrophotographic printing apparatus, and opens the old process cartridge 12 in which all the toner has been consumed.
Is taken out, and a new process cartridge 12 is set.

However, in this state, the display such as "drum replacement" on the display does not disappear.
Therefore, after setting the new process cartridge 12 in the electrophotographic printing apparatus, the operator turns on the switch 44 while pressing a menu switch (not shown) of the operation unit 45, and then presses the menu switch several times. , The counter 47 is reset so that the display disappears.

In this embodiment, the toner cartridge 21 can be attached to and detached from the process cartridge 12. However, a process chamber having a dedicated chamber for accommodating the toner integrally with the process cartridge is formed. In the cartridge, when it is detected that all the toner in the process cartridge has been consumed, an indication such as "drum replacement" is displayed.

Next, the operation of the electrophotographic printing apparatus having the above configuration will be described. FIG. 3 is a flowchart showing the operation of the electrophotographic printing apparatus according to the first embodiment of the present invention. When the operator turns on the switch 44 (FIG. 1) and turns on the power supply 43, the control unit 31 generates an idling command and determines whether or not a new process cartridge 12 has been set by the judgment means (not shown), that is, the counter 47. To determine if has been reset. If the counter 47 has not been reset, the control unit 31 starts preparations for starting an idling operation under normal driving conditions. That is, the control unit 31 turns on the heater 41 by the heater drive control unit 42, raises the temperature of a fixing unit (not shown) to a predetermined fixing temperature, and performs warm-up. continue,
The drive torque changing means (not shown) of the control unit 31 sets the drive conditions so that the drive motor 34 generates a normal drive torque.

Then, the control unit 31 controls the drive motor 3 by the motor drive control unit 35 for the set time under the drive conditions.
4 is driven to perform idling. Therefore, in order to stabilize the state of the surface of the photosensitive drum 13 and stably charge the toner in the process cartridge 12, the rollers in the process cartridge 12 are rotated for a set time.

Thereafter, the control unit 31 waits until the next operation is performed by the operator. On the other hand, when the counter 47 is reset when the operator turns on the switch 44 and turns on the power supply 43, the control unit 31
Upon recognizing that the new process cartridge 12 has been set in the electrophotographic printing apparatus, preparations for starting an idling operation under unusual driving conditions are started. That is, the control unit 31 turns on the heater 41 by the heater drive control unit 42, raises the temperature of the fixing unit to a predetermined fixing temperature, and performs warm-up. Subsequently, the drive torque changing unit performs idling by increasing the drive torque generated by the drive motor 34.

When the motor drive control section 35 increases the current supplied to the drive motor 34 in accordance with the drive conditions, the drive motor 34 generates a drive torque larger than usual and causes the rollers and the like of the process cartridge 12 to rotate. To rotate. In this way, when the idling is performed for the set time, the toner reaches the entire inside of the process cartridge 12 with the rotation of the rollers, and the toner acts as a lubricant, and each sliding portion of the process cartridge 12 , The rotational load gradually decreases. Accordingly, the state of the surface of the photosensitive drum 13 can be stabilized, and the toner in the process cartridge 12 can be stably charged.

Thereafter, the drive torque changing means sets the drive conditions again so that the drive motor 34 generates a normal drive torque, and the control unit 31 waits until the next operation is performed by the operator. As described above, when a new process cartridge 12 is set in the electrophotographic printing apparatus, idling is performed for a set time with a drive torque larger than usual, and then printing is performed with a normal drive torque, and the power supply 43 is also used. Is shut off and then turned on again, idling is performed with a normal driving torque. Therefore, when designing an electrophotographic printing apparatus, it is necessary to rotate the rollers of the process cartridge 12 more than necessary. Therefore, it is not necessary to select the drive motor 34 having the drive torque described above, so that the cost of the electrophotographic printing apparatus can be reduced and the size of the electrophotographic printing apparatus can be reduced.

Further, since it is not necessary to select a drive motor 34 having a drive torque more than necessary, the acceleration at the time of starting the electrophotographic printing apparatus can be set high, and the controllability can be improved. Further, noise can be reduced and printing pitch accuracy can be increased. Note that the set time is set in the process cartridge 12.
And a margin set for the drive torque of the drive motor 34. Step S1 The power supply 43 is turned on. Step S2: Generate an idling instruction. Step S3: The judging means judges whether or not the counter 47 has been reset. If the counter 47 has been reset, the process proceeds to step S6; otherwise, the process proceeds to step S4. Step S4 Warm up is performed. Step S5: The drive motor 34 is driven for a set time under normal drive conditions to perform idling. Step S6: Recognize that the new process cartridge 12 has been set in the electrophotographic printing apparatus. Step S7 Warm up is performed. Step S8: The drive torque changing means increases the current supplied to the drive motor 34. Step S9: Idling is performed for a set time. Step S10 The drive torque changing means sets a normal drive condition.

By the way, a new process cartridge 1
When the current is increased to generate a large drive torque when the drive motor 2 is set in the electrophotographic printing apparatus, the amount of heat generated by the drive motor 34 itself increases. If there is no margin in the temperature of 34 or if there is no margin in the capacity of the power supply 43, the above-described embodiment cannot be adopted.

Therefore, a second embodiment of the present invention will be described. FIG. 4 is a flowchart showing the operation of the electrophotographic printing apparatus according to the second embodiment of the present invention.
In the present embodiment, when a new process cartridge 12 (FIG. 2) is set in the electrophotographic printing apparatus, the current supplied to the drive motor 34 by the drive torque changing means (not shown) of the control unit 31 (FIG. 1). Is lowered, and the drive motor 34 is driven in a low-speed region. Therefore, idling is performed for a set time with a driving torque larger than usual.

In this case, since the number of rotations of the drive motor 34 is reduced, the time required for the toner to reach the entire inside of the process cartridge 12 with the rotation of the rollers of the process cartridge 12 is increased. Therefore, the set time is lengthened by an amount corresponding to a decrease in the rotation speed of the drive motor 34. In addition, while the drive frequency of the current is reduced, the number of rotations of the drive motor 34 changes, so that it is necessary to simultaneously change the electrophotographic process itself during idling and the time chart of the electrophotographic process. For example, the charging voltage applied to the charging roller 14, the timing of applying the charging voltage, the developing bias voltage applied to the developing roller 15, the timing of applying the developing bias voltage, and the like are changed according to the rotation speed. There is a need.

As described above, in this embodiment, when a new process cartridge 12 is set in the electrophotographic printing apparatus, the driving frequency of the current is reduced to generate a large driving torque. Therefore, since the amount of heat generated by the drive motor 34 itself does not increase, even if the temperature of the drive motor 34 does not already have a margin or the capacity of the power supply 43 does not have a margin in the design stage of the electrophotographic printing apparatus, it is larger than usual. A driving torque can be generated. Step S11 The power supply 43 is turned on. Step S12: Generate an idling instruction. Step S13: The judging means judges whether the counter 47 has been reset. If the counter 47 has been reset, the process proceeds to step S16; otherwise, the process proceeds to step S14. Step S14 Warm up is performed. Step S15: The drive motor 34 is driven for a set time under normal drive conditions to perform idling. Step S16: Recognize that a new process cartridge 12 has been set in the electrophotographic printing apparatus. Step S17 Warm up is performed. Step S18: The drive torque changing means is the drive motor 34
The driving frequency of the current supplied to is reduced. Step S19: Idling is performed for a set time. Step S20: The drive torque changing means sets a normal drive condition.

In the first and second embodiments, when a new process cartridge 12 is set in the electrophotographic printing apparatus, it is supplied to the drive motor 34 in order to generate a drive torque larger than usual. Since the current to be generated is increased or the driving frequency of the current is reduced, the motor drive control unit 35, the power supply circuit of the electrophotographic process, and the like become complicated.

Therefore, a third embodiment of the present invention will be described. FIG. 5 is a flowchart showing the operation of the electrophotographic printing apparatus according to the third embodiment of the present invention.
In the present embodiment, a pulse motor is used as the drive motor 34 (FIG. 1), and when a new process cartridge 12 (FIG. 2) is set in the electrophotographic printing apparatus,
By a drive torque changing unit (not shown) of the control unit 31,
The slewing condition at the time of starting the drive motor 34 is changed. For example, at the start of normal printing, the slewing time at the start of the drive motor 34 is set to the minimum necessary length in order to increase the printing speed, but a new process cartridge 12 is installed in the electrophotographic printing apparatus. When set, the slewing time is set longer. This allows
The acceleration of the drive motor 34 can be reduced, and the drive torque can be increased.

Therefore, it is possible to prevent the step-out phenomenon from occurring when the drive motor 34 is started. In this case, it is only necessary to substantially change the firmware unit (not shown) of the motor drive control unit 35, so that the cost of the electrophotographic printing apparatus can be reduced. Step S21 The power supply 43 is turned on. Step S22: Generate an idling instruction. Step S23: The judging means judges whether or not the counter 47 has been reset. If the counter 47 has been reset, the process proceeds to step S26; otherwise, the process proceeds to step S24. Step S24 Warm up is performed. Step S25: The drive motor 34 is driven for a set time under normal drive conditions to perform idling. Step S26: to recognize that a new process cartridge 12 has been set in the electrophotographic printing apparatus. Step S27 Warm up is performed. Step S28: The driving torque changing means is the driving motor 34
To increase the slewing time. Step S29: Idling is performed for the set time. Step S30: The drive torque changing means sets a normal drive condition.

The first to third embodiments can be combined as needed. Further, the excitation method of the drive motor 34 is changed so that the drive motor 34 is normally driven by the 1-2 phase excitation. When a new process cartridge 12 is set in the electrophotographic printing apparatus, the drive is performed by the 2 phase excitation. The driving torque can be increased by driving the motor 34.

The present invention is not limited to the above embodiment, but can be variously modified based on the gist of the present invention, and they are not excluded from the scope of the present invention.

[0033]

As described above in detail, according to the present invention, in an electrophotographic printing apparatus, an image forming means for performing printing by an electrophotographic process, and a driving means for rotating rollers of the image forming means. And a driving torque changing unit that increases the driving torque generated by the driving unit when the new image forming unit is set and performs idling.

In this case, when a new image forming means is set in the electrophotographic printing apparatus, idling is performed for a set time with a driving torque larger than usual, and thereafter printing is performed with a normal driving torque. When the power is turned off and then turned on again, idling is performed with a normal drive torque. Therefore, in designing the electrophotographic printing apparatus, it is not necessary to select a driving means having a driving torque more than necessary to rotate the rollers of the image forming means, and the cost of the electrophotographic printing apparatus can be reduced. In addition, the size of the electrophotographic printing apparatus can be reduced.

Further, since it is not necessary to select a driving means having a driving torque more than necessary, the acceleration at the time of starting the electrophotographic printing apparatus can be set high, and the controllability can be improved. Further, noise can be reduced and printing pitch accuracy can be increased.

[Brief description of the drawings]

FIG. 1 is a control block diagram of an electrophotographic printing apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram of an electrophotographic printing apparatus according to the first embodiment of the present invention.

FIG. 3 is a flowchart illustrating an operation of the electrophotographic printing apparatus according to the first embodiment of the present invention.

FIG. 4 is a flowchart illustrating an operation of the electrophotographic printing apparatus according to the second embodiment of the present invention.

FIG. 5 is a flowchart illustrating an operation of the electrophotographic printing apparatus according to the third embodiment of the present invention.

[Explanation of symbols]

 12 Process Cartridge 13 Photoconductor Drum 14 Charging Roller 15 Developing Roller 18 Sponge Roller 31 Controller 34 Drive Motor

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[Procedure amendment]

[Submission date] September 26, 1997

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Figure 2

[Correction method] Change

[Correction contents]

FIG. 2

Claims (7)

[Claims] 1. An image forming means for performing printing by an electrophotographic process, (b) a driving means for rotating rollers of the image forming means, and (c) when a new image forming means is set. An electrophotographic printing apparatus, comprising: a driving torque changing unit that performs idling by increasing a driving torque generated by the driving unit. 2. The electrophotographic printing apparatus according to claim 1, further comprising a determination unit configured to determine whether the new image forming unit has been set. 3. The electrophotographic printing apparatus according to claim 1, wherein the drive torque changing means increases the drive torque for a set time. 4. The electrophotographic printing apparatus according to claim 1, wherein said drive torque changing means increases a current supplied to said drive means. 5. The electrophotographic printing apparatus according to claim 1, wherein said drive torque changing means lowers a drive frequency of a current supplied to said drive means. 6. The electrophotographic printing apparatus according to claim 1, wherein (a) the driving means is a pulse motor, and (b) the driving torque changing means changes a slewing condition at the time of starting the pulse motor. 7. The electrophotographic printing apparatus according to claim 1, wherein (a) the driving means is a pulse motor, and (b) the driving torque changing means changes an excitation method of the pulse motor.