JPS62109070A - Image forming device - Google Patents

Abstract

PURPOSE:To eliminate the waiting time when there is no need for a pretreatment by providing a timer means which starts when a power source is interrupted and when a unit is removed and providing a control means which varies the pretreatment according to the result of detection by detecting the output when the power source is thrown or an image forming operation is started to a main body. CONSTITUTION:The voltage at the point A falls to a low level when the unit 3 is mounted and the voltage rises to a high level when the unit 3 is removed. A switch turns on when a front door is closed and the switch turns off when the power source is interrupted and when the front door is opened. The output B of a comparator circuit 23 rises to a high level when the contact 22 is closed. Conversely the output inverts from a high level to a low level when the contact 22 is opened. The timer starts operating if the output B of the comparator circuit 23 is of the high level. A developer is stirred for 4sec when the power source is thrown again within 1hr after the interruption of the power source or when the front door is closed within 1hr after opening. The developer in the unit is stirred for 1min when the output B of the comparator circuit is of the low level. The attenuation of the electrostatic charge potential of the developer or the like is, therefore, eliminated when the power source is thrown again upon lapse of the set time after the interruption of the power source.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an image forming apparatus in which a unit consisting of one or a combination of image forming parts such as a photoreceptor and a developing device is configured to be detachably attached to the main body of the apparatus. The present invention relates to an image forming apparatus suitable for replacing different units depending on the color of toner.

[Traditional technique]

2. Description of the Related Art Conventionally, this type of apparatus includes, for example, one in which a photosensitive drum, a developing device, and a cleaning device are integrated into a unit, and this unit is replaced. By replacing the unit, consumable parts such as the photosensitive drum can be replaced, developer can be replenished, and waste toner can be disposed of at the same time. In addition, printing in various colors is performed by distinguishing units for each toner color and installing a unit containing a tree of a desired color before printing.

In such cases, since the unit is equipped with a developing device and the developing device contains developer, if the unit is left unused for a long period of time, the charged potential of the developer may attenuate or the developer may become semi-solid. condition may occur. Furthermore, if the developer is a two-component developer, the toner concentration of the developer may be partially uneven. Therefore, when replacing the unit, that is, when replacing the unit by opening the front door of the main body of the image forming apparatus, or when turning on the power, a preprocessing process is always performed to stir the developer before printing. The stirring time of the developer at this time is generally about 1 minute, which requires a relatively long time.

[Problems with conventional technology]

However, in the above-mentioned apparatus, the developer agitation pre-treatment described above is required even when the power is turned on again after being turned off for a short time, or when the front door is opened in the event of a jam, for example. I will do it. Therefore, it is wasteful to pre-process the developer beyond what is necessary, and
This was inconvenient because it was necessary to wait about one minute until the stirring was completed.

[Purpose of the invention]

In view of the above drawbacks, the present invention performs pre-processing of developer stirring only when the image forming apparatus is stopped for a long time or when the unit is replaced, and when the power is turned off for a short time or when the front door is opened. An object of the present invention is to provide an image forming apparatus that eliminates waiting time when preprocessing is not required by stirring the developer for an extremely short time.

[Summary of the invention]

In order to achieve the above object, the present invention is configured such that an image forming unit including at least a developing device can be replaced with the main body of the image forming apparatus, and when the power is turned on, when the unit is attached, or prior to image forming operation, In an image forming apparatus capable of performing pre-processing such as stirring the developer contained in the image forming apparatus, the image forming unit is provided with a timer means that starts when the power is cut off or when the unit is removed, and the main body includes a power source for the timer means. The apparatus is characterized in that it is provided with a control means that detects the output at the time of input or the start of the image forming operation and changes the pre-processing according to the detection result.

[Embodiments of the invention]

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, the configuration of the image forming apparatus will be explained. FIG. 3 shows a perspective view of the image forming apparatus, and FIG. 4 shows a schematic configuration diagram.

In the figure, reference numeral 1 denotes the main body of the image forming apparatus, and a front door 2 is provided on the front surface so that the main body 1 can be opened and closed, and an opening 4 in which an image forming unit 3 (hereinafter referred to as unit) is installed is located approximately in the center of the main body 1.
has. As shown in FIG. 4, the unit 3 has a developing device 6 and a cleaning device 7 arranged around the photosensitive drum 5, and these parts are integrally constructed to form a unit. The unit 3 is configured to be removably attached to the opening 4 of the main body 1, so that by replacing the unit 3, printing in different colors can be performed. That is, units 3 are prepared for different toner colors, such as red, blue, and black, and printing in a desired color is performed by replacing the units 3.

A protrusion 8 is provided on the inside of the front door 2 to protrude, a slit 9 is formed on the main body 1 side opposite to the protrusion 8, and a door switch to be described later is disposed within the slit 9. This door switch is configured to be turned on when the projection 9 is pushed when the front door 2 is closed, and turned off when the front door 2 is opened. In addition, this door switch is connected in series with the power switch 10 of the main body 1, and when the power switch 10 is turned on and the front door 2 is closed, the door switch is turned on.
The configuration is such that power is supplied to the main body l. In the figure, 11 is a display unit using a liquid crystal or the like, 12 is a charger that charges the photosensitive drum 5, 13 is an exposure unit that exposes the photosensitive drum 5, and 14 is a device that charges the paper 15 and applies it to the circumferential surface of the photosensitive drum 5. A transfer charger for adsorption is shown. Further, reference numerals 17 and 18 denote a pair of fixing rolls, one of which has a heater 19 inside and a thermistor 20 attached to its circumferential surface.

Then, the surface temperature is detected by the thermistor 20, and a temperature control circuit, which will be described later, controls the supply of electricity to the heater 19 according to this detected value, thereby controlling the surface temperature of the fixing roll 17 to be constant.

FIG. 1 shows a circuit diagram of an embodiment of the present invention. FIG. 1 shows the main parts of the present invention, and the control system of other image forming apparatuses is omitted.

In the figure, numeral 3 is a unit configured to be detachably attached to the main body 1 as described above, and the unit 3 includes a shorter 21 and a time constant circuit consisting of a resistor R2 and a capacitor C3 connected in parallel. When unit 3 is installed, a, b, c
The body 1 and the unit 3 are connected at the points respectively, thereby resistor R.

and short circuit 21 are connected in series, resistor R1 is grounded, and resistor R3 and a time constant circuit are connected in series. Therefore, when the unit 3 is attached, the voltage at point A in the figure becomes a low level, and when the unit 3 is removed, the voltage becomes a high level. Reference numeral 22 denotes a relay contact, which is turned on when the front door is closed with the power turned on, and turned off when the power is turned off and the front door is opened. When the contact 22 is on, the capacitor C1 is charged through the resistor R1, and the power supply voltage ■. The resistors R2 and R
Voltage V divided by 3, (v.・R2/R2+R3
). This charging time is instantaneous because the resistance value of the resistor R3 is made small as shown in FIG. Then, the voltage V is input to the non-inverting terminal (+ terminal) of the comparator circuit 23, and the power supply voltage ■ is input to the inverting terminal (one terminal) as a reference voltage. voltage divided by resistors R4 and R6 ■2
(Vo - Rs / R4 + R5) is input. When the unit 3 is installed, the constant of each resistor is set so that the voltage of the capacitor c1 becomes high, and as a result, V>V, the output B of the comparator circuit 23 becomes high level.

On the other hand, when the power is cut off or the front door is opened, the relay contact 22 is turned off, so that the charge in the capacitor C1 starts discharging through the resistor R2. This discharge start is performed in the same way when the unit 3 is removed. The discharge time of the charge in the capacitor c1 is long due to the use of a high resistance resistor Rz, and in this embodiment, as shown in FIG.
The time for discharging from 1 to 2 was 1 hour. Therefore,
One hour after relay contact 22 turns off, V, <V
2, and the output B of the comparison circuit is inverted from high level to low level. Further, numeral 24 in the figure is a temperature control circuit that controls the surface temperature of the fixing roll 17 to be constant by controlling the supply of electricity to the heater 19 as described above. The output C of the temperature control circuit is at a low level before reaching a predetermined temperature when the power is turned on, and when the temperature reaches the predetermined temperature, the output C becomes a high level and is outputted as a print enable signal to the main control section.

FIG. 5 is a flowchart showing the operation of the above embodiment. The operation will be explained below with reference to the same figure.

First, in step (hereinafter referred to as ST) 1, if the input/output described above is at a low level, that is, if the unit is attached to the main body 1 and the resistor R1 is grounded, the main motor is started by Sr2, and the input/output is at a low level. If the output is at a high level, the main motor will not operate.0 then Sr3 comparator circuit 23
If the output B of is at a high level, a 4-second timer (not shown) is started in Sr1. The 4-second timer is a timer that determines the stirring time of the developer in the unit, and outputs a high-level signal from the comparison circuit 23 to the main control section, thereby causing the developer stirring device (not shown) provided in the developing device to switch to Sr5. Stir the developer for 4 seconds until the timer goes up. In other words, the conditions for the output of the comparator circuit 23 to be at a high level are, as described above, the voltage of the capacitor CI,
is higher than the reference voltage (2), and the output of the comparator circuit 23 maintains a high level within one hour after the power is cut off and the front door is opened. Therefore, if the power is turned on again within one hour after the power was turned off, or if the front door is opened and
If it closes within this time, the developer is stirred for a short period of 4 seconds. This is based on the reason that changes such as attenuation of the charging potential of the developer do not occur within one hour after the power is shut off. Furthermore, even if the front door is opened, the unit is removed, and the unit is reinstalled within one hour, the voltage of capacitor C1 (■1) is higher than (■2), so the output B of the comparator circuit becomes high level, and the above Similarly, the stirring time of the developer is 4 seconds. Although an example is shown in which the developer is stirred for 4 seconds, the present invention is not limited to this, and the developer may be stirred for more or less than that, or may not be stirred at all. Further, the developer stirring device is operated by the driving force of the main motor.

On the other hand, in Sr3, when the comparison circuit output B is at a low level, this low level signal becomes a developer stirring signal, and a 1-minute timer (not shown) is activated in Sr3.
is started, a stirring device (not shown) is activated, and the developer in the unit is thereby stirred for one minute. In other words, the conditions under which the output B of the comparator circuit 23 becomes low level are when the voltage (1) of the capacitor C1 is lower than (2), when more than one hour has passed since the power was cut off, and when the pressure door has been opened for more than one hour. It is. Therefore, in the case of the above two conditions, the developer is sufficiently stirred to prevent the charge potential from attenuating, etc., and to perform good development. Further, when the front door is opened, the unit is removed, and another unit is installed, for example, to change the toner color, the voltage of the capacitor CI is low because the unit is left alone. As a result, the output B of the comparator circuit becomes a low level, so the developer is stirred for one minute in the same manner as above. Incidentally, when the timer is activated after one minute as shown as Sr1, stirring of the developer is stopped.

When the stirring of the developer is completed in Sr1 and Sr1, the rotation of the main motor stops in Sr1, and then the rotation of the main motor in Sr1 is stopped.
1, the relay contact 22 is turned on and the capacitor C1
Recharge the battery and prepare for the next power outage. After this, 5TI
Only when the output C of the temperature control circuit 24 is at a high level at O, that is, when the surface temperature of the fixing roll rises to a predetermined temperature, the printer enters a print standby state, outputs a ready signal, and displays it on the display. do.

Note that the discharge time of the capacitor C1 is set to be sufficiently long, the relay contact 22 is turned on during the image forming operation, and the output B of the comparison circuit 23 is determined prior to the image forming operation, and the actual image forming operation is determined based on this determination result. It is also possible to vary the amount of time the developer is agitated prior to the agitation. With this configuration, the developer can be stirred even if no image forming operation is performed for a long time after the power is turned on.

As described above, when the power is turned on again after the set time has elapsed since the power was cut off, the developer is sufficiently stirred, so problems such as the attenuation of the charging potential of the developer can be solved, and the problem is good. development can be performed. Furthermore, even when the unit is removed, as long as the set time has elapsed, the developer can be sufficiently stirred and good development can be performed. on the other hand,
When the front door is opened for a short time, such as when the power is turned off for a short time or to remove jammed paper, the developer is stirred for a short time, eliminating the waiting time required when stirring is not required. .

In addition, in the embodiment, an example was shown in which the developer is stirred by the driving force of the main motor, but the present invention is not limited to this, and a dedicated motor may be provided. In addition, in the example, an example was shown in which the stirring time of the developer was varied, but when the photoreceptor is subjected to pretreatment such as light irradiation or charging when the power is turned on, the pretreatment time, light amount, and charging voltage may be varied. It is also possible to control the condition so that no pretreatment is performed if it is left for a short period of time.

〔Effect of the invention〕

As explained above, according to the present invention, since preprocessing is performed only when necessary when a set time has elapsed since the power was cut off or the unit was removed, the waiting time for unnecessary preprocessing can be eliminated. be.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram of an embodiment of the present invention, and Fig. 2 is a time chart 1-1 showing the operation of the embodiment of Fig. 1.
1. FIG. 3 is a perspective view showing the external appearance of the image forming apparatus, FIG. 4 is a schematic configuration diagram of the image forming apparatus, and FIG. 5 is a flow chart showing the operation of the above embodiment. DESCRIPTION OF SYMBOLS 1... Image forming apparatus main body, 2... Front door, 3... Image forming unit, 4... Opening, 5... Photosensitive drum, 6... Developing device, 10... Power switch , 21... Show 1-bar, 22... Relay contact, 23... Comparison circuit, 24... Temperature control circuit, C,... Capacitor, R+, R2, R3... Resistor. Patent Applicant Casio Computer Co., Ltd. Same as above Casio Electronics Industries Co., Ltd. Figure 1 Diagram 2 - Φ

Claims (1)

[Scope of Claims] 1) An image forming unit including at least a developing device is configured to be replaceable in the main body of the image forming apparatus, and the developer in the unit is In an image forming apparatus capable of performing pre-processing such as stirring, the image forming unit is provided with a timer means that starts when the power is turned off or when the unit is removed, and the main body is provided with a timer means that starts when the power is turned on or when the image forming unit is turned on or when the image forming unit is turned on. Detects the output at the start of the forming operation,
An image forming apparatus characterized by comprising a control means for changing the pre-processing according to the detection result. 2) The image forming apparatus according to claim 1, wherein the timer means includes a time constant circuit that discharges the charge of a charged capacitor using a resistor. 3) The image forming apparatus according to claim 1, wherein the control means varies the stirring time of the developer in the unit depending on the detection result of the timer means.