JP2000075566A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and precisely execute the correction (setting) of an image forming process condition corresponding to the environment state of temperature or the like regardless of the constitution content of an image forming device. SOLUTION: This image forming device possesses an environment sensor 45 detecting at least temperature in the vicinity of a position on a side opposed to the thermal fixing unit 30 of an image forming system 10, an environment predicting means calculating the environment state (temperature) of the image forming system 10 or its each constituting part by using the information on the temperature detected at the time of starting image forming by the environment sensor 45 and the information on the distance L of the image forming system or each constituting part for the thermal fixing unit 30 and a condition setting means setting the image forming process condition of the image forming system 10 or its each constituting part to be a proper condition based on the environment predicting information of the image forming system 10 or its each constituting part obtained by the environment predicting means.

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 such as a copying machine and a printer using an electrophotographic system, and more particularly to an image forming apparatus for setting image forming process conditions corresponding to environmental conditions. .

[0002]

2. Description of the Related Art In an image forming apparatus using an electrophotographic system, basically, a photoreceptor is uniformly charged by a charger, and then a light image corresponding to image information is exposed by an exposure device to form an electrostatic latent image. Then, after the electrostatic latent image is developed by a developing device into a toner image, the toner image is transferred to a recording material such as paper by a transfer device. Then, the toner image transferred to the recording material is heat-fixed by a heat fixing device to form an image.

In such an image forming apparatus, environmental conditions such as temperature and humidity in the apparatus main body change due to the influence of heat released from the thermal fixing device. Due to the change, the image quality obtained by finely changing the characteristics of the photosensitive member, the exposure device, the developing device, the transfer device, and the like during the image forming process, which has a large temperature dependency, may be changed. In addition, since such a tendency has been restricted by space due to a demand for downsizing of the apparatus in recent years, the above-described components having large temperature dependence have been brought closer to the thermal fixing device. It has also become remarkable due to the fact that it has been installed in the country and that it has become difficult to take sufficient heat insulation measures.

For this reason, conventionally, when environmental conditions such as temperature change, the process conditions of components related to the image forming process are corrected to appropriate conditions in accordance with the environmental conditions, whereby the environmental conditions are changed. Measures have been taken to suppress fluctuations in image quality.

For example, Japanese Patent Application Laid-Open No. 4-60553 discloses that an environment sensor disposed near a developing device detects a temperature near the developing device and stores the temperature for a predetermined time, and stores information on the detected temperature and elapsed time. An image forming apparatus has been proposed which sets image forming conditions (determined by a charging potential of a photoreceptor, an exposure amount, a latent image potential, and a developing bias potential) for determining an image density based on the image density.

Japanese Patent Application Laid-Open No. 4-198952 discloses a so-called tandem-type image forming apparatus in which a plurality of photosensitive drums are arranged side by side. The temperature and humidity sensors of the developing device are individually provided, and the temperature and humidity in the vicinity of the developing device of the photosensitive drum arranged in the middle are obtained by interpolating from the information obtained by the two sensors. An image forming apparatus has been proposed in which image forming conditions are set based on temperature and humidity information in the vicinity of each developing unit in the photosensitive drum.

[0007]

However, in the former image forming apparatus, although it is possible to accurately cope with the environmental situation near the developing unit, the environment of each component other than the developing unit involved in the image forming process is considered. Since the image forming conditions are not corrected after grasping the situation, for example, the above-described components during the image forming process depend on the arrangement state of the components, the separation distance from the fixing device, the state of heat transmission, and the like. However, there is a problem that it is not possible to sufficiently cope with the case where the image quality fluctuates due to individual changes of the characteristics.

On the other hand, the latter image forming apparatus always requires two environmental sensors for detecting temperature and humidity, so that it is possible to avoid the cost increase and the necessity of securing the installation space. There is no problem.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems. Specifically, the present invention does not cause a significant increase in cost, and regardless of the constitution of an image forming apparatus, It is an object of the present invention to provide an image forming apparatus that can more easily and accurately correct (set) an image forming process condition corresponding to an environment of humidity and humidity.

[0010]

The image forming apparatus of the present invention (the invention according to claim 1), which can achieve the above object, is as follows.
An image forming system including a plurality of components for forming a toner image according to image information and transferring the toner image to a recording material, and a heat fixing device for thermally fixing the toner image transferred by the image forming system to the recording material are provided. In the image forming apparatus, environment detecting means for detecting at least a temperature near a position on the opposite side of the heat fixing device of the image forming system, environment detection information detected at the start of image formation by the environment detecting means, and An environment estimating means for calculating an environmental state of the image forming system or each component thereof using information on a heat reaching distance of the image forming system or each component thereof with respect to a thermal fixing device; and Based on the environment prediction information of the image forming system or each component thereof, the image forming process conditions of the image forming system or each component thereof are set. Is intended to and a condition setting means for setting a positive condition.

Here, the environment predicting means basically includes:
Assuming that the temperature of the thermal fixing device is kept substantially constant at a temperature near the fixing temperature, the image forming system or the components of the image forming system using the environment detection information and the heat reach distance information described above. It calculates the environmental situation. Incidentally, the heat reach distance information includes the physical separation distance between the heat fixing device and the image forming system or each of its components, and the time required for the heat from the heat fixing device to be actually transmitted and affected. The distance of a concept that also takes into account the degree of heat transmission. Therefore, in this case, when the thermal fixing device is at a temperature near the fixing temperature, the environment predicting unit measures or simulates a change in temperature or humidity at a location where the environment detecting unit is installed to pattern the detection information of the environment detecting unit. Divide,
Further, under the respective environmental conditions of the environment detecting means divided into the respective patterns, the state of the temperature and humidity at the installation location of the image forming system or the respective components thereof is actually determined by the heat reaching with the heat fixing. What is associated with the relationship with the distance is prepared in advance as collation data or a calculation formula, and the environment state of the image forming system or each component thereof is calculated according to the environment information detected by the environment detection unit thereafter. .

In addition to the environment prediction method based on the pattern classification method, the environment prediction means performs primary interpolation based on the detected environment information and data stored at a specific temperature or information based on a calculation formula. The environmental condition may be calculated from the obtained information. Note that this environment predicting means can calculate the above-mentioned environmental condition even under a condition where the temperature of the thermal fixing device has not reached the fixing temperature.

It is preferable that a plurality of the image forming systems are provided, but one may be provided. The plurality of components constituting the image forming system include, for example,
Examples include a photoreceptor, a charging device, an exposure device, a developing device, and a transfer device.

According to such an image forming apparatus, the environment predicting means basically uses the environment detecting information obtained at the start of image formation by one environment detecting means (the image forming system for the thermal fixing device or each component thereof). The environmental condition of the image forming system or each component thereof is calculated by taking into account the heat reach distance information. Then, the image forming process conditions are set to appropriate conditions based on the environment prediction information.

Further, in this image forming apparatus, a timer means for measuring an elapsed time from when the power of the image forming apparatus main body is turned on, and an elapsed time measured at the start of the image formation by the timer means, are fixed by the heat fixing device. Determining means for determining whether or not the time required to reach the temperature has been reached; and, for the environment predicting means, environment detection information obtained by the environment detecting means obtained at the time when the elapsed time has been reached by the determining means. Alternatively, the environmental status of the image forming system or each component thereof may be calculated by using the elapsed time information obtained by the timer unit.

In such a configuration, the calculation of the environmental condition by the environment predicting means includes the detection information by the environment detecting means obtained at the time when it is confirmed that the required time to reach the fixing temperature has been reached after the power is turned on. This is performed taking into account the information on the elapsed time obtained by the timer means at the time of confirmation. Thus, for example, when the power is turned on for the first time on that day, when the thermal fixing device has reached the fixing temperature, but the temperature in the apparatus main body is in the process of raising the temperature and is not in a steady state (detection of the environment detecting means). Even when the result is in a fluctuating state), an image forming process condition suitable for the state can be obtained and set from the elapsed time.

Further, in the case of this image forming apparatus, there is provided a calculating means for calculating the time required to reach the fixing temperature of the thermal fixing device using the environment detection information obtained by the environment detecting means obtained when the power of the image forming apparatus body is turned on. In addition, the determination means may be configured to make a determination based on the required fixing temperature arrival time obtained by the calculation means.

In such a configuration, an appropriate time required to reach the fixing temperature in consideration of the environmental condition of the thermal fixing device when the power is turned on is calculated, and the elapsed time from when the power is turned on is calculated based on the appropriate required time. And the environmental status is calculated by the environment prediction means. Accordingly, for example, when the power is turned off and then turned on again, and the temperature of the thermal fixing device is not completely cooled but is warm, the actual time required for the fixing device to reach the fixing temperature is shortened. As a result, the environment prediction by the environment predicting means and the condition setting by the condition setting means after the required time to reach the fixing temperature has been reached can be efficiently executed without time loss. Further, as in the case of the above-described image forming apparatus, even when the heat fixing unit has reached the fixing temperature but the temperature in the apparatus main body is in the process of raising the temperature and has not yet reached the steady state, the state of the thermal fixing unit is determined from the elapsed time. The image forming process conditions suitable for the above can be obtained and set.

Further, in the image forming apparatus according to the first aspect, the first elapsed time from when the power of the image forming apparatus main body is turned off to the next power on and the second elapsed time from when the power is turned on are set. Timer means for measuring, environment change predicting means for calculating the amount of change between environment detection information obtained immediately before the power-off by the environment detection means and environment detection information obtained at the time of power-on; Calculating means for calculating the time required to reach the fixing temperature of the thermal fixing device using the change amount information obtained by the above and the environment detection information obtained by the environment detecting means obtained when the power is turned on; Determining means for determining whether or not the second elapsed time has reached the required fixing temperature arrival time obtained by the calculating means. The environment of the image forming system or each component thereof is used together with the environment detection information obtained by the environment detection unit and the second elapsed time information obtained by the timer unit when the arrival of the second elapsed time by the determination unit is confirmed. You may comprise so that a situation may be calculated.

In such a configuration, an appropriate time required to reach the fixing temperature corresponding to a situation from when the power is turned off to when the next power is turned on is calculated, and the power is turned on based on the appropriate required time. The arrival of the second elapsed time from the time is determined, and the environmental condition is calculated by the environment predicting means. As a result, similarly to the case of the above-described image forming apparatus, the environment prediction by the environment predicting unit and the setting of the condition by the condition setting unit after the fixing temperature has reached the fixing time are efficiently executed without time loss. Even when the fixing device has reached the fixing temperature but the temperature in the apparatus main body is in the process of raising the temperature and has not yet reached the steady state, the image forming process conditions suitable for the state can be determined and set from the second elapsed time. it can.

[0021]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

[First Embodiment] FIG. 1 is a schematic diagram of a color image forming apparatus to which the present invention is applied. This color image forming apparatus is arranged side by side in the vertical and vertical directions to exclusively use one of the four color toner images of black (K), yellow (Y), magenta (M) and cyan (C). Image forming systems 10K, 10Y, 10 formed in
M and 10C, a sheet conveying device 20 that conveys a recording sheet P as a recording material through each transfer position where the toner image formed by each image forming system 10 is transferred, and each image forming system A heat fixing device 30 for thermally fixing the toner image transferred to the recording paper P at 10 is disposed at a predetermined position in the apparatus main body (outer cover or frame) 40.

The image forming system 10 includes a photosensitive drum 11, a roll type charging device 12, a laser beam type exposure device 13, a developing device 14 containing any of the four color toners, and a roll type. Transfer device 15,
The main part is constituted by components such as the drum cleaner 16.

The photosensitive drum 11 is rotated in the direction of arrow A by a drive motor (not shown). The charging device 12 has a charging roll that rotates in contact with the photoconductor drum 11, and charges the photoconductor drum 11 to a predetermined surface potential by applying a predetermined charging voltage from a power supply (not shown) to the charging roll. It has become. The exposure device 13 includes a semiconductor laser and an optical system, and emits a laser beam Bm oscillated from the semiconductor laser on the surface of the photosensitive drum 11 in accordance with image information (signal) transmitted from an image processing device (not shown). An electrostatic latent image is formed by directing and irradiating with an optical system.

Incidentally, the image information is, for example, image information of a copy original read by an original reading device when the image forming apparatus is a copying machine, and is provided by an external device or the like when the image forming apparatus is a printer. Print information created and input. Note that the exposure device 13 is an LED.
An apparatus using an array or the like may be used.
An optical system for guiding a reflected light image of a document obtained by a document reading device in an analog type copying machine to the photosensitive drum 11 and irradiating the same with the reflected light image may be used.

The developing device 14 includes the photosensitive drum 11
A developing roll that rotates at a position facing the photosensitive drum 11, and supplies toner contained in the apparatus to a position (developing area) facing the photosensitive drum 11. By applying a predetermined developing bias from a power source, the photosensitive drum 1
The toner is electrostatically attached only to the one latent image portion. The transfer device 15 has a transfer roll that rotates in contact with the photosensitive drum 11, and applies a predetermined transfer current from a power supply (not shown) to the transfer roll to transfer the toner image on the photosensitive drum 11 to the recording paper P side. To be electrostatically transferred to

The paper transport device 20 includes a plurality of rolls 22 to
An endless transport belt 21 that is stretched around a roller 24 (the roll 22 is a driving roll) and rotates in the direction of arrow B is
The belt 21 between the roll 2 and the roll 23 is disposed so as to pass between the photosensitive drum 11 and the transfer device 15 (corresponding to a transfer position) of each image forming system 10. Then, the recording paper P supplied from the feed tray 25 by the feed roll 26 or the registration roll 27 is attracted to the transport belt 21 so that the recording paper P is transported so as to sequentially pass through each of the transfer positions described above. Has become. Reference numeral 28 in the drawing denotes a belt cleaner.

The heat fixing device 30 is a roll-type fixing device provided with a heating roll 31 and a pressure roll 32 which rotate while being pressed. The heat fixing device 30 has a cover 33 in which a portion through which the recording paper P passes is opened. The surface temperature of the heating roll 31 is measured by a temperature sensor 34, and the measurement result is The heating roll 3 is fed back to the control unit 56 of the heating source 35 and
1 is controlled so as to be heated to a predetermined fixing temperature (see FIG. 2).

In this color image forming apparatus, each of the above image forming systems 10K, 10Y, 10M,
10C, the heat reaching distance L with the heat fixing device 30 is L
_K , L _Y , L _M , and L _C are provided in such a positional relationship as to be L. Each of the heat reaching distances L is not only a physical separation distance between the heat fixing device 30 and each image forming system 10, but also the heat released from the heat fixing device 30 actually reaches (transmits) each image forming system 10. ) Means the distance taking into account the required time.

The lowermost image forming system 10
An environment (temperature) sensor 45 as an environment detecting means for measuring the temperature around the transfer position of K is located near the transfer position of K.
Are arranged.

Further, as shown in FIG. 2, there is provided a control system for appropriately setting image forming process conditions according to the environment (particularly temperature).

In FIG. 3, reference numerals 51K, 51Y, 51
M, 51C are the respective image forming systems 10K, 10Y, 1
A control unit for individually controlling the process conditions for each of 0M and 10C. Each of the control units controls the charging potential of the charging device 12, the exposure amount of the exposure device 13 (latent image potential), and the development of the developing device 14 in each image forming system 10. The bias, the transfer current of the transfer device 15, and the like can be set as appropriate. Reference numeral 50 denotes a central control unit having a function of comprehensively calculating appropriate image forming process conditions according to environmental conditions and individually transmitting the conditions to each control unit 51. The central control unit 50 is connected to each control unit 50, and further includes an environment sensor 45, a random access memory (RAM).
52, a read-only memory (ROM) 53 storing control contents for setting process conditions according to the above-mentioned environmental conditions, a power switch, a start switch, operation buttons, a display unit, and the like are provided. An operation unit 54, a timer 55 for counting elapsed time, and the like are connected. Further, reference numeral 56 denotes a heating roll 31 in the fixing device 30.
The temperature control unit 56 is connected to the above-described temperature sensor 34, and is connected to the heating roll 32.
(The power source).

Further, it has been confirmed by actual measurement tests and the like that the color image forming apparatus has a temperature environment characteristic as shown in FIG. FIG. 3 shows how the image forming system 10 is at various temperatures detected by the environment sensor 45 when the thermal fixing device 30 is kept substantially constant at a temperature near the fixing temperature Dm. Are shown together with the heat reaching distance L to the fixing device 30. From FIG. 3, the temperature of each image forming system 10 is determined to be a certain value as the heat reach distance L to the fixing device 30 increases, irrespective of the difference in the detection temperature (high temperature, medium temperature, low temperature) of the environment sensor 45. It can be confirmed that the ratio gradually decreases.

Accordingly, in this control system, when the environment sensor 45 detects the temperature of "high temperature" which is a predetermined high temperature region, "environment 1" is used, and similarly, "medium temperature" which is a medium temperature region is used. Patterns are classified as “environment 2” when detected, and “environment 3” when detected as “low temperature” which is a low-temperature region. Then, when the environment sensor 45 detects each temperature in the pattern, the central control unit 50 automatically sets the temperature as shown in FIG. 3 as the temperature of each image forming system 10 based on the detected information. A calculation formula and a control program to be calculated are stored in the ROM 53. Further, the ROM 53 also stores a calculation formula and a control program such that the central control unit calculates an appropriate process condition of each image forming system 10 based on the calculated temperature information of each image forming system 10. .

Next, the operation of the color image forming apparatus will be described.

First, an image forming process for forming a full-color image will be described. First, when a start button on the operation unit 54 is pressed and an image forming (printing) start instruction is received, each image forming system 10 and the sheet conveying device 20 start operating, and the heat fixing device 30 is also started to activate its heating roll. Heating starts until 31 reaches the fixing temperature.

In each of the image forming systems 10, after the surface of the rotating photosensitive drum 11 is uniformly charged to a predetermined surface potential by a charging device 12, a laser beam Bm is emitted by an exposure device 13 in accordance with image information. Irradiation forms an electrostatic latent image having a predetermined surface potential. Subsequently, the electrostatic latent image is developed by a developing device 14 to which a predetermined developing bias is applied, so that the photosensitive drum 1
1 is formed with a toner image of a predetermined color.

Subsequently, the black, yellow, magenta, and cyan toner images formed by each image forming system 10 are supplied to the transport belt 21 of the paper transport device 20 at a predetermined timing, and pass through each transfer position. The recording paper P conveyed as described above is sequentially transferred electrostatically and superposedly by the transfer device 15 in a state where a predetermined transfer current is applied.

After the transfer by the image forming system 10C is completed, the recording paper P is separated from the transport belt 21 of the paper transport device 20, and then sent to the heat fixing unit 30 to be fixed. That is, the recording paper P after the transfer passes through the pressure contact portion between the heating roll 31 and the pressure roll 32 heated to the predetermined fixing temperature, so that the toner of the toner image is heated and pressed, and is placed on the paper P. It is fused.

Finally, the recording paper P after fixing is sent out from the heat fixing device 30 and is discharged out of the apparatus main body 40 by the discharge roll 41. Through the above process, the formation of a basic full-color image is completed.

In a color image forming apparatus in which such an image is formed, the temperature inside the apparatus main body 40 gradually rises due to the high temperature heat emitted from the heat fixing unit 30 in particular.
Thus, each image forming system 10 is also affected by the heat. At that time, the temperature environment in which each image forming system 10 is placed is also individually different (particularly, the temperature environment is affected by the difference in the distance from the fixing device 30. Is affected by the convection state and the heat insulation structure). If the characteristics of the image forming system 10 during the image forming process fluctuate due to the temperature change, the image quality of the obtained image also fluctuates. Therefore, in the color image forming apparatus, the control system as described above is provided.

Next, the operation of the control system relating to the setting of image forming process conditions corresponding to the environment (particularly temperature) conditions in the color image forming apparatus will be described with reference to the flowchart of FIG.

In the case of a control system in this image forming apparatus,
When the power supply of the apparatus main body 40 is turned “ON” by the control unit 54 (Step 1: S1), the heating of the heating roll 31 of the thermal fixing device 30 is started, and thereafter, when a print start command is issued for the first time ( S2) Prior to the printing (image formation), control relating to the setting of the following process conditions is executed.

First, the temperature is detected by the environment sensor 45 (S3), and the central control unit 50 is operated based on the detected information.
Then, the temperature condition of each image forming system 10 described above is calculated (S4). That is, when the temperature information detected by the environment sensor 45 is one of the high temperature, the medium temperature, and the low temperature, the temperature information is discriminated as the environment 1, the environment 2, or the environment 3, respectively, and each detection result (the environment 1, 2, the 3), the temperatures T _K , T _Y , T _M ,
T _C is calculated by performing arithmetic processing according to the control program.

At this time, the respective temperatures T _K , T _Y , T _M , T _C
Is a heat source because the temperature around the heat fixing unit 30 is substantially the same as the fixing temperature Dm, and the heat reach distance L of each image forming system 10 from the heat fixing unit 30 is known. When the temperature of the heat fixing unit 30 is substantially equal to the fixing temperature Dm, the fixing unit 3 in which the temperature environment is constant can be fixed.
For example, according to the heat reaching distance L from 0, the fixing temperature Dm
Is multiplied by a predetermined coefficient (multiplication) to obtain the temperature at the position of each system 10.
The temperatures T _K , T _Y , T _M ,
T _C, that each a value commensurate with the temperature characteristic shown in FIG.

The above temperature T may be obtained, for example, by using the following calculation formula. T = A _n e ^-x {wherein, A _n environmental factor (n = 1, 2,
3 ...), x is about} environmental coefficient A _n indicating the distance from the fixing device is different environmental factor according to the environment detection information detected is selected.

Subsequently, the central control unit 50 calculates the predicted temperatures T _K , T _Y , T T of the calculated image forming systems 10.
Based on _M and T _C , an appropriate condition of the image forming process condition in the system 10 is calculated based on, for example, preset collation data or the like (or from collation data obtained by linearly interpolating the calculated temperature information), The obtained condition is set as a new process condition in the control unit 51 of each system 10 (S5). As the process condition changed according to the temperature condition at this time, for example, as shown in FIG. 5, there is a correlation characteristic between the surface potential of the photosensitive drum 11 and the exposure amount of the exposure device 13. That is, the correlation characteristic may be appropriately changed according to the detected temperature environments 1, 2, and 3. The process conditions changed according to the temperature condition are not limited to the contents of the conditions, but may be, for example, conditions such as a charging potential, a developing bias potential, a transfer voltage, and a transfer current.

After the setting of the new image forming process conditions in step 5 is completed, the printing specified previously is executed. The printing operation at this time is performed by the control unit 51 under the newly set process conditions.
This is performed by the image forming system 10 controlled by.

As a result, each image forming system 10 in the color image forming apparatus operates before the image formation is started, with the image forming process conditions changed and set to (corresponding to) the temperature environment at that time. As a result, the obtained image is good without fluctuation in image quality due to temperature change.

[Second Embodiment] This embodiment is the same as the first embodiment except that the control contents for setting the image forming process conditions corresponding to the temperature environment are slightly changed in the image forming apparatus according to the first embodiment. Has the same configuration as the image forming apparatus according to the first embodiment.

That is, in the control system according to the present embodiment, the elapsed time t from when the power of the apparatus main body is turned “ON” by the operation unit 54 is measured by the timer 55, and the elapsed time t is set in advance. The central control unit 50 determines whether or not the time required to reach the fixing temperature Tn of the thermal fixing unit 30 has been reached.
Is determined. Then, the central control unit 50, consists of the information of the temperature detected by the elapsed time t _n and the environment sensor 45 when it reaches the fixing temperature reaches the required time Tn so that the temperature of the image forming system 10 is calculated ing.

Further, it has been confirmed by an actual measurement test or the like that the color image forming apparatus has a temperature environment characteristic immediately after the power is turned on as shown in FIG. FIG.
When the power is turned on, the relationship between the temperature detected by the environment sensor 45 at each elapsed time t after the power is turned on and each temperature state of each image forming system 10 at that time is compared with the fixing device 30. It is shown together with the heat reaching distance L. From FIG. 6, according to the elapsed time t, that is,
From the initial state (t = t0) before the power is turned on, the state where the temperature of the fixing unit 30 is rising (t = t1), and the state where the temperature of the fixing unit 30 is steady (the fixing temperature Dm) ( t =
t2) In a state where the temperature in the apparatus main body 40 has become steady (t2).
= T3), it can be confirmed that the temperature of each image forming system 10 gradually changes at a specific ratio according to the heat reaching distance L with the fixing device 30.

Therefore, in this control system, after the elapsed time t reaches the fixing temperature required time Tn (after the heat fixing unit 30 reaches the fixing temperature Dm), the environmental sensor 4
5, the case where the temperature at the predetermined elapsed time t2 is detected is referred to as "environment 4", and the case where the temperature at the elapsed time t3 is detected is similarly referred to as "environment 5". Then, when the environment sensor 45 detects each temperature in the pattern, the central control unit 50 determines the temperature of each image forming system 10 based on the detected information as shown in FIG. The calculation formula and control program for automatically calculating the temperature as shown in FIG.
It is stored in M53.

Next, the operation of the control system of the image forming apparatus according to the present embodiment having such a configuration will be described with reference to the flowchart of FIG.

In the case of a control system in this image forming apparatus,
When the power supply of the apparatus main body 40 is turned “ON” in the operation unit 54 (Step 10: S10), the heating of the heating roll 31 of the thermal fixing device 30 is started, and at the same time, the timer 5 is turned on.
5, the elapsed time t starts to be measured (S11). Thereafter, when a print start command is issued for the first time (S
12) Prior to the printing, the following control regarding the setting of the process conditions is executed.

First, the elapsed time t up to that time is measured by the timer 55 (S13), and it is determined by the central control unit 50 whether or not the elapsed time t has reached the required fixing temperature arrival time Tn (S14). . While the elapsed time t does not reach the required time Tn, the time measurement by the timer 55 and the determination by the control unit 50 are continued, but when the elapsed time t reaches the required time Tn, the heat fixing device 30 assumes that became temperature Dm, the temperature detected by the environment sensor 45 the elapsed time t _n at that time is determined with performed (S15).

Subsequently, the central control unit 50 controls each image forming system 1 based on the detected information (temperature and elapsed time).
It is calculated for a temperature condition of 0 (S16). In other words, when the temperature information detected by the environment sensor 45 is the temperature at any one of the elapsed times t2 and t3, it is determined that the temperature is the environment 4 or the environment 5, respectively, and the respective detection results (environment 4, 5) ), The temperatures T _K , T _Y , T _M , and T _{C of the} image forming systems 10 are calculated and processed according to the control program.

At this time, the respective temperatures T _K , T _Y , T _M , T _C
Since the thermal fixing device 30 after the power is turned on has reached the fixing temperature Dm based on the measurement and determination of the elapsed time, and the heat reaching distance L between the thermal fixing device 30 of each image forming system 10 and the thermal fixing device 30 is known. The temperature of the heat fixing device 30 which is a heat source is a fixing temperature D.
m, which can be substantially fixed. For example, by multiplying the fixing temperature Dm by a predetermined coefficient in accordance with the heat reaching distance L from the fixing device 30 in which the temperature environment is constant, Determined as temperature. In addition, the temperatures T _K , T _Y , and T calculated at this time.
_M, T _C is a value commensurate with the temperature characteristics shown in FIG. 6 also either. In addition, primary interpolation may be performed based on the information on each temperature T and data on a specific temperature stored in advance or information on a calculation formula, and the temperature at the position of each system 10 may be calculated from the interpolated information. Good.

Subsequently, the central control unit 50 calculates the predicted temperatures T _K , T _Y , T T of the respective image forming systems 10.
Based on _M and T _C , an appropriate condition of the image forming process condition in the system 10 is calculated in the same manner as in the first embodiment, and the obtained condition is set as a new process condition in the control unit 51 of each system 10. Is set (S
17). Then, after the setting of the new image forming process condition in step 17 is completed, the printing specified previously is executed under the new setting condition.

Thus, in the image forming system 10 of this color image forming apparatus, for example, when the power is turned on for the first time on that day, the heat fixing unit 30 has reached the fixing temperature but the temperature inside the apparatus main body 40 has been lowered. When the temperature is in the middle of a temperature rise and the steady state has not been reached (in other words, when the detection result of the environment sensor 45 is in a fluctuating state, in this example, “t
= 2)), the operation is performed in a state where the image forming process condition change setting suitable for the state is set based on the elapsed time t and the detected temperature information at that time. Even if there is a change, the image quality does not fluctuate due to a change in temperature, and is excellent.

[Third Embodiment] The third embodiment is different from the image forming apparatus according to the second embodiment except that the control contents concerning the setting of the image forming process conditions corresponding to the temperature environment are slightly changed. Has the same configuration as the image forming apparatus according to the first embodiment.

That is, in the control system according to this embodiment, the temperature is detected by the environment sensor 45 when the power supply of the apparatus main body is turned “ON” by the operation unit 54,
The central control unit 50 calculates the required fixing temperature reaching time Tn of the thermal fixing unit 30 based on the detected temperature, and uses the obtained required time Tn to reduce the elapsed time t from when the power is turned on to the required time Tn. It is configured to determine whether or not it has reached. Then, the same configuration as the second embodiment except for the this, the central control unit 50, the information of the temperature detected by the elapsed time t _n and the environment sensor 45 when it reaches the fixing temperature reaches the required time Tn The temperature of each image forming system 10 is calculated.

In this color image forming apparatus, as in the case of the second embodiment, it has been confirmed by an actual measurement test or the like that there is a temperature environment characteristic immediately after the power is turned on as shown in FIG.

Next, the operation of the control system of the image forming apparatus according to the present embodiment having such a configuration will be described with reference to the flowchart of FIG.

In the case of a control system in this image forming apparatus,
When the power of the apparatus main body 40 is turned “ON” in the operation unit 54 (Step 20: S 20), the heating of the heating roll 31 of the thermal fixing device 30 is started, and at the same time, the timer 5
5, the elapsed time t starts to be measured, and the temperature is detected by the environment sensor 45 (S21). Subsequently, in the central control unit 50, based on the detected temperature, the required fixing temperature arrival time Tn is determined based on, for example, collation data or a calculation formula that previously obtained the relationship between the power-on temperature and the required fixing temperature arrival time ( Alternatively, it is calculated (based on collation data interpolated based on the detected temperature) (S22). afterwards,
When a print start command is issued for the first time (S2
3) Prior to the printing, the following control regarding the setting of the process conditions is executed.

First, the elapsed time t up to that time is measured by the timer 55 (S24), and the central controller 50 determines whether or not the elapsed time t has reached the previously calculated required fixing temperature reaching time Tn. Is performed (S25). When the elapsed time t reaches the required time Tn, the heat fixing device 3
0 is deemed to have become the fixing temperature Dm, the temperature detected by the environment sensor 45 the elapsed time t _n at that time is determined with performed (S26).

Subsequently, in the central control unit 50, the embodiment
As in the case of 2, the detected information (temperature and elapsed time)
Based on the temperature condition of each image forming system 10 based on the
(S27), and thereafter, each of the calculated image forming
Predicted temperature T of stem 10 _K, T_Y, T_M, T_CBased on
Image forming process conditions in the system 10
Appropriate conditions are calculated, and the obtained conditions
In the control unit 51 of each system 10 as process conditions
It is set (S28). And in this step 28
After setting new image forming process conditions
In addition, the print specified in advance
And executed.

Accordingly, each image forming system 10 in this color image forming apparatus can be fixed even if the power is turned off and then turned on again and the temperature of the thermal fixing unit 30 is not completely cooled but is still warm. It is possible to cope with the fact that the actual required time Tn until the device 30 reaches the fixing temperature Dm becomes shorter, and as a result, the temperature condition of each image forming system 10 after the required time Tn for reaching the fixing temperature has been reached. The calculation and the setting of the process conditions are executed efficiently without any time loss.

Further, as in the case of the second embodiment, even when the temperature of the heat fixing unit 30 has reached the fixing temperature but the temperature in the apparatus The operation is performed in a state in which an image forming process condition change suitable for the state is set based on the elapsed time t and the detected temperature information. It is good without fluctuation.

[Fourth Embodiment] This embodiment is the same as the first embodiment except that the control contents for setting the image forming process conditions corresponding to the temperature environment are slightly changed in the image forming apparatus according to the first embodiment. Has the same configuration as the image forming apparatus according to the first embodiment.

That is, the control system according to the present embodiment is configured such that the elapsed time e from the time when the power of the apparatus main body is turned “OFF” at the operation unit 54 to the time when the power is next turned “ON” and the time when the power is turned “ON” the elapsed time t from being "is measured by the timer 55, also the detected temperature D ₀ of the environment sensor 45 in the power OFF immediately before the power ON
Δ from the detected temperature D ₁ of the environment sensor 45 at the time
D (D ₀ −D ₁ ) is calculated in the central control unit 50,
Further, the central control unit 50 calculates the required fixing temperature reaching time Tn from the amount of change ΔD in the detected temperature by the sensor and the detected temperature D ₁ when the power is turned on.
The central control unit 50 is configured to determine whether or not the elapsed time t has reached the calculated required time Tn. Other than this, the first embodiment
And have the same configuration, the central control unit 50, the temperature of the elapsed time t _n and the image forming system 10 from the information of the temperature D ₁ detected by the environment sensor 45 when it reaches the fixing temperature reaches the required time Tn is It is calculated.

[0072] Further, in the color image forming apparatus, that there is a temperature environment characteristic definitive after power OFF, as shown in FIG. 9 has been confirmed by actual measurement test and the like. FIG.
When the power is turned off, the relationship between the temperature detected by the environment sensor 45 at each elapsed time e after the power is turned off and each temperature state of each image forming system 10 at that time is determined by the relationship with the fixing device 30. It is shown together with the heat reaching distance L. From FIG. 9, from the elapsed time e, that is, from the state immediately after the power is turned off (e = e0),
The state where the temperature in the apparatus main body 40 is falling (e = e
1), a state in which the temperature of the fixing device 30 is decreasing (e = e
2) As the initial state, that is, the state where both the fixing device and the apparatus main body are completely cooled (e = e3), the temperature of each image forming system 10 depends on the heat reaching distance L with the fixing device 30. Thus, it can be confirmed that it gradually changes at a specific ratio.

From this, in this control system, the temperature state of the thermal fixing device 30 differs depending on the elapsed time e, and the required fixing temperature reaching time Tn is calculated by taking this into consideration while measuring the elapsed time e. Like that. In the third embodiment, the heat fixing device 3 when the power is turned on is set.
Although the required time Tn was calculated after predicting the temperature state of 0 from the temperature detected by the environment sensor 45, in this embodiment, the heat fixing unit is used by using the elapsed time e from the power OFF to the next power ON. The required time Tn is calculated more accurately after accurately determining the temperature state of the temperature 30.

Next, the operation of the control system of the image forming apparatus according to the present embodiment having such a configuration will be described with reference to FIG.
This will be described with reference to the flowchart of FIG.

In the case of the control system in this image forming apparatus,
When the power of the apparatus main body 40 is turned "OFF" in the operation unit 54 (Step 30: S30), the elapsed time e starts to be measured by the timer 55 (S31). Thereafter, when the electric cancer is turned “ON” again within a relatively short time (S3
2), the heating of the heating roll 31 of the heat fixing device 30 is started, and at the same time, the measurement of the elapsed time t is started while the measurement of the elapsed time e by the timer 55 is finished, and the temperature of the temperature is detected by the environment sensor 45. Detection is performed (S3
3).

[0076] Subsequently, the central control unit 50, the change amount ΔD between the detected temperature D ₀ by the detected temperature D ₁ and the power source OFF immediately preceding sensor 45 is calculated (S34), thereafter, the amount of change ΔD in the previous The time Tn required to reach the fixing temperature from the elapsed time e is used to predict, for example, the temperature of the fixing unit when the power is turned on, and as described above, the collation data (or the primary data) obtained from the temperature at the time when the power is turned on and the commercial time at which the fixing temperature is reached. It is calculated based on the interpolated data) (S35). Thereafter, when the instruction of the print start command is issued for the first time (S36),
Prior to the printing, the following control regarding the setting of process conditions is executed. The control operation at this time is almost the same as in the third embodiment.

First, the elapsed time t from when the power is turned on is measured by the timer 55 (S37), and the central control unit 50 determines whether or not the elapsed time t has reached the previously calculated required fixing temperature reaching time Tn. Is determined (S38). If the elapsed time t has reached the required time Tn is assumed that the thermal fixing device 30 reaches the fixing temperature Dm, the elapsed time t _n is determined at that time with the temperature detected by the environment sensor 45 is performed Is performed (S39).

Subsequently, the central control unit 50 calculates the temperature condition of each image forming system 10 based on the detected information (temperature and elapsed time) as in the second and third embodiments (S40). Thereafter, the calculated predicted temperatures T _K , T _Y , T _M , and T of the respective image forming systems 10 are calculated.
Based on _C , an appropriate condition of the image forming process condition in the system 10 is calculated, and the obtained condition is set in the control unit 51 of each system 10 as a new process condition (S41). And this step 4
After the setting of the new image forming process conditions in step 1 is completed, the printing specified earlier is executed under the new setting conditions.

Thus, in this color image forming apparatus, an appropriate fixing temperature reaching time Tn corresponding to the situation from the time when the power is turned off to the time when the next power is turned on is calculated by measuring the elapsed time e, and the appropriate time is calculated. Based on the required time Tn, it is determined whether or not the elapsed time t has elapsed since the power was turned on.

Each of the image forming systems 10 in the image forming apparatus includes a heat fixing unit 30 when the power is turned on.
After more accurately grasping the temperature situation than in the third embodiment, a more appropriate fixing temperature reaching time Tn can be calculated, and thereafter, as in the third embodiment,
The calculation of the temperature state of each image forming system 10 and the setting of the process conditions after the fixing temperature reaching required time Tn has been reached can be executed efficiently without any time loss. Further, even after the power is turned off and the thermal fixing unit 30 has reached the fixing temperature but the temperature in the apparatus main body 40 is in the process of raising the temperature and has not yet reached the steady state, the elapsed time t
And the information of the detected temperature, it will operate in the state where the image forming process condition change suitable for that state is set,
Even if the image is obtained immediately after the power is turned on, the image is excellent without fluctuation in image quality due to a temperature change.

[Other Embodiments] In the first to fourth embodiments, the setting of the image forming process conditions corresponding to the temperature environment is changed. However, the humidity environment and the conditions corresponding to the temperature and humidity environment are changed. The configuration may be changed.

In the first to fourth embodiments, the temperature condition of each image forming system 10 is grasped by one environment sensor 45, and the image forming process conditions suitable for the temperature condition are changed. The temperature environment of the fixing device 30 is detected by the temperature sensor 34 of the heating roll 31 in the fixing device 30, and the detected information is used for predicting the temperature condition of each image forming system 10 and calculating and setting the image forming process conditions. May be. Specifically, for example, by using the temperature detected by the temperature sensor 34 together with the temperature detected by the environment sensor 45, each image system 1
It is possible to predict the environmental situation of 0 with higher accuracy. Further, it is possible to directly determine whether or not the thermal fixing device 30 has reached the fixing temperature by detecting the temperature by the temperature sensor 34.

Further, in the first to fourth embodiments, as a so-called tandem type color image forming apparatus, an example in which the image forming systems 10 are arranged vertically and vertically is used. The present invention is also applicable to other image forming systems 10 as shown in FIGS.
The present invention can be similarly applied to a tandem-type color image forming apparatus having an arrangement in which are arranged in the horizontal direction. In FIG. 12, reference numeral 60 denotes an intermediate transfer belt device, 65 denotes a roll type secondary transfer device, and 69 denotes a sheet transport belt. When there is the intermediate transfer belt device 60,
The toner image formed by each image forming system 10 is temporarily (multiplexed) transferred onto the intermediate transfer belt, and then secondarily transferred onto the recording paper P. FIG. 11 and FIG.
In the case of the image forming apparatus shown in FIG.
The heat reaching distance L of the thermal fixing device 30 is schematically shown, for example, as shown in FIG.
5 is arranged at a position as shown in the figure.

Further, the present invention is not limited to a tine-type image forming apparatus, but can be similarly applied to other types of image forming apparatuses as exemplified in FIG. 13 and FIG. The image forming apparatus illustrated in FIG. 13 includes one image forming system 10 that forms a single-color toner image, and the image forming apparatus illustrated in FIG. 14 includes one image forming apparatus that can form a full-color toner image. An image forming system 10 is provided. In FIG. 14, reference numeral 70 denotes a rotary developing device in which four developing devices 14 containing any of black toner, yellow toner, magenta toner, and cyan toner are disposed on a cylindrical rotating support 71, and Developing device 1 required for development by rotation of support 71
4 moves to a position facing the photosensitive drum 11. In the case of the image forming apparatus shown in FIGS. 13 and 14, heat reaches the thermal fixing units 30 such as the photosensitive drum 11, the exposing device 13, the developing device 70, and the transfer device 15 which constitute the image forming system 10. The distance L is considered important,
The heat reaching distance L is schematically illustrated.
In the case of these devices, the environment sensor 45 is disposed at a position as shown.

[0085]

As described above, according to the image forming apparatus of the present invention, the information of environment detection such as temperature detected by one environment detecting means and the image forming system for the heat fixing device or each component thereof. By using the known information of the heat reach distance, the environmental condition of the image forming system or each component thereof is calculated, and based on the obtained environment predictive information, an appropriate value corresponding to the environmental condition such as the temperature is calculated. Correction (setting) of image forming process conditions can be performed more easily and accurately. Such correction of process conditions can be performed simply and accurately in the same manner irrespective of the configuration of the image forming apparatus, and the cost is greatly increased because only one environment detecting means is required. There is no fear. Therefore, with this image forming apparatus, it is possible to stably perform good image formation in which image quality fluctuations due to environmental changes such as temperature hardly occur.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a main part of an image forming apparatus according to a first embodiment.

FIG. 2 is a block diagram illustrating a control system related to setting of image forming process conditions corresponding to environmental conditions.

FIG. 3 is a correlation diagram illustrating a relationship between a heat reaching distance and a temperature in a heat fixing device and each image forming system, and a detection state of an environment sensor.

FIG. 4 is a flowchart showing an operation content of a control system according to the first embodiment.

FIG. 5 is an explanatory diagram illustrating an example of setting image forming process conditions (correlation characteristics between the surface potential of a photoconductor and an exposure amount) set according to environmental conditions.

FIG. 6 is a correlation diagram showing a relationship between a heat reaching distance and a temperature in the thermal fixing device and each image forming system after power is turned on, and a relationship between a state detected by an environment sensor and an elapsed time.

FIG. 7 is a flowchart showing an operation content of a control system according to the second embodiment.

FIG. 8 is a flowchart showing an operation content of a control system according to the third embodiment.

FIG. 9 is a correlation diagram showing a relationship between a heat reaching distance and a temperature in the heat fixing device and each image forming system after power is turned off, and a relationship between a detection state by an environment sensor and an elapsed time.

FIG. 10 is a flowchart showing an operation content of a control system according to the fourth embodiment.

FIG. 11 is a main part explanatory view showing a configuration example of a stretched state at a primary transfer position of the intermediate transfer belt.

FIG. 12 is a main part schematic diagram showing another example of a tandem type image forming apparatus to which the present invention is applied.

FIG. 13 is a schematic diagram illustrating a main part of an example of an image forming apparatus other than a tandem type to which the present invention is applied.

FIG. 14 is a schematic diagram illustrating a main part of another example of an image forming apparatus other than the tandem type to which the present invention is applied.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Image forming system, 30 ... Heat fixer, 45 ... Environment sensor (environment detection means), 50 ... Central control part (environment prediction means, condition setting means, determination means, calculation means, environment change prediction means), 51 ... Control unit (condition setting means), 55: timer means, P: recording paper (recording material), L: heat reach distance,
t: elapsed time (first elapsed time) since power-on, Tn
... time required to reach the fixing temperature, e ... second elapsed time.

Continued on the front page (72) Inventor Naoko Odashima 2274 Hongo, Ebina-shi, Kanagawa Prefecture, F-term in Fuji Xerox Co., Ltd. (reference) 2H027 DA11 DA12 DA38 DE07 DE10 EA12 EC06 ED25 EE02 EF01 EF04 EF06 FA28 2H033 AA02 AA39 BA32 BB00 CA03 CA08 CA30 CA44

Claims (4)

[Claims] An image forming system comprising a plurality of components for forming a toner image according to image information and transferring the toner image to a recording material, and a heat for thermally fixing the toner image transferred by the image forming system to the recording material. An image forming apparatus having a fixing unit, wherein an environment detecting unit that detects at least a temperature near a position on the opposite side of the thermal fixing unit of the image forming system;
Using the environment detection information detected at the start of image formation by the environment detection unit and the heat reach distance information of the image forming system or each component thereof with respect to the heat fixing device, the image forming system or each component thereof is An environment predicting means for calculating an environmental condition, and an image forming process condition of the image forming system or each component thereof being appropriately set based on environment prediction information of the image forming system or each component thereof obtained by the environment predicting means. An image forming apparatus comprising: condition setting means for setting conditions. 2. An apparatus according to claim 1, wherein a timer means for measuring an elapsed time from when the power of the image forming apparatus main body is turned on, and an elapsed time measured at the start of image formation by said timer means, Determining means for determining whether the required time to reach the fixing temperature has been reached; and, for the environment predicting means, detecting the environment by the environment detecting means obtained at the time when the elapsed time has been reached by the determining means. An image forming apparatus configured to calculate the environmental status of the image forming system or each component thereof by using both the information and the elapsed time information by the timer unit. 3. An apparatus according to claim 2, further comprising a calculating means for calculating a time required to reach a fixing temperature of the thermal fixing device using environment detection information obtained by the environment detecting means obtained when the power of the image forming apparatus main body is turned on. An image forming apparatus configured to make a determination based on the required time to reach the fixing temperature obtained by the calculation unit. 4. The image forming apparatus according to claim 1, wherein the first time from when the power of the main body of the image forming apparatus is turned off to when the next power is turned on.
Timer means for measuring an elapsed time and a second elapsed time from when the power is turned on;
Environmental change prediction means for calculating the amount of change between the environment detection information obtained immediately before and the environment detection information obtained when the power is turned on; and the change amount information obtained by the environment change prediction means and the information obtained when the power is turned on. Calculating means for calculating a time required to reach the fixing temperature of the thermal fixing device using environment detection information obtained by the environment detecting means, and a second elapsed time measured at the start of image formation by the timer means. A determining means for determining whether or not the required time to reach the fixing temperature has been reached; and
Environment detection information obtained by the environment detecting means obtained at the time when the arrival of the elapsed time is confirmed, and a second
An image forming apparatus configured to calculate an environmental status of an image forming system or each component thereof using the elapsed time information together.