JP2000221654A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal developing device having superior reproducibility and stability, that concentration is automatically compensated according to environment and. SOLUTION: Relating to this image forming device, a most appropriate temperature is calculated again to be higher by a temperature adjustment device 102, a heater 100 is controlled and a thermal developing drum 84 is heated automatically until its temperature reaches the newly calculated most appropriate temperature when the temperature and humidity of the image forming device is lowered and the lowering of the temperature and humidity is detected by a temperature sensor 36A and a humidity sensor 36B. Furthermore, the most appropriate temperature is calculated again to be lower by the temperature adjustment device 102 when the temperature and humidity inside the image forming device is risen and the rising of the temperature and the humidity is detected by the temperature sensor 36A and the humidity sensor 36B and the control is carried out to lower the temperature of the thermal developing drum 84 to the newly calculated most appropriate temperature.

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, and more particularly, to a method of applying an image forming solvent to a photosensitive material or an image receiving material to which an image has been exposed, and then bonding the photosensitive material and the image receiving material. The present invention relates to an image forming apparatus that performs a heat development process by transporting the photosensitive material and the image receiving material bonded to the surface of a heat development drum while making them contact with each other.

[0002]

2. Description of the Related Art An image forming apparatus has been proposed in which an image is exposed on a photosensitive material, a heat development process is performed in a state in which the exposed photosensitive material is bonded to an image receiving material, and the image is transferred to an image receiving paper. ing.

In the above-mentioned thermal development processing, when an image is transferred from a photosensitive material to an image receiving material, it is performed in the presence of an image forming solvent. As the solvent for image formation, water can be used, a water coating device is provided in the process of transporting the photosensitive material or the image receiving material, and in a process before bonding.

[0004] The water application device is provided with a storage tank for storing water. The bottom surface of the storage layer is formed in an arc shape to guide the photosensitive material or the image receiving material in a substantially arc shape, whereby the photosensitive material entering the storage tank at a predetermined incident angle has a predetermined emission angle. Will be sent out of the storage tank.

[0005] By passing through the water application device, water is applied to one of the photosensitive material and the image receiving material, and can have a function as an image forming solvent at the time of bonding.

[0006] The photosensitive material and the image receiving material, which are coated with water and adhered, are conveyed along the outer peripheral surface of a heat developing drum or the like. A heater is housed inside the thermal developing drum, and the thermal developing drum is heated by the heater.
Therefore, the photosensitive material and the image receiving material conveyed along the outer peripheral surface of the heat developing drum are heated for a predetermined time (ie,
Thermal development processing is performed). Thus, the photosensitive material and the image receiving material are subjected to the heat development process, whereby an image exposed to the photosensitive material is formed on the image receiving material.

By the way, the image forming apparatus is required to reproduce the density and stability, that is, to always form the same image at the same density.

[0008] The density of the formed image depends on the amount of exposure during image exposure, the temperature of the applied water, and the amount of heating in the heat development process (that is, the surface temperature of the heat development drum). Therefore, the image forming apparatus controls the exposure amount when exposing an image, controls the temperature of the water stored in the water application device, and controls the temperature of the surface of the thermal developing drum.

The density of the formed image also depends on the environment (temperature and humidity) due to the nature of the photosensitive material. That is, when the temperature and humidity (hereinafter collectively referred to as “temperature and humidity”) change, even if the amount of exposure, the temperature of the water to be applied, and the amount of heating in the heat development process have become the predetermined values by the above-described control, they are formed. Density deviation occurs in the image.

Conventionally, in order to cope with the density deviation due to the environment (temperature and humidity), a picture is drawn at the beginning of the use of the image forming apparatus, the result of the picture is measured and a correction amount is determined. Subsequent painting was performed using the amount (so-called calibration).

Specifically, the exposure amount control for exposing an image, the temperature control of the water stored in the water application device, and the temperature control of the surface of the heat developing drum are prepared in advance. The test image data is subjected to image forming processing to form a test image on a receiving paper. The color of the test image formed on the image receiving paper is measured by a colorimeter, and the colorimetric result is compared with the original test image data to determine the density deviation. The amount of correction for correcting the density deviation is determined by calculating backward from this. In the subsequent image forming process, the original image data was corrected using this correction amount, and the corrected image data was exposed to a photosensitive material.

[0012]

However, if the environment (temperature and humidity) of the image forming apparatus changes after the correction amount is determined,
The density of the formed image is shifted. Conventionally, each time the density shifts, the correction must be redone each time to change the correction amount.

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat developing apparatus which automatically corrects the density in accordance with the environment in consideration of the above facts and has excellent density reproducibility and stability.

[0014]

In order to achieve the above object, according to the first aspect of the present invention, an image is exposed by irradiating a light-sensitive material with a beam light, and a coating material containing a solvent for image formation is stored. After applying the image forming solvent by immersing the photosensitive material or the image receiving material in a tank, the photosensitive material and the image receiving material are attached to each other, and while being brought into contact with the surface of the heat developing drum heated to a predetermined temperature by heating means. In an image forming apparatus that performs a heat development process by transporting and forms an image on an image receiving material, a temperature detection unit that detects a temperature in the device, a humidity detection unit that detects humidity in the device, and the temperature Based on the detection result of the temperature and humidity by the detecting unit and the humidity detecting unit, the exposure amount of the photosensitive material,
Temperature of the image forming solvent stored in the coating tank,
And calculating an optimum value for at least one of a plurality of parameters of the surface temperature of the heat developing drum, and calculating the exposure amount, the temperature of the image forming solvent, and the surface temperature of the heat developing drum according to the optimum value. And control means for controlling at least one of them.

According to the first aspect of the invention, the temperature and humidity detecting means detects the temperature and humidity in the image forming apparatus on which the density of the image formed on the image receiving paper depends. The density of the image formed on the image receiving paper also depends on the exposure amount when exposing the image to the photosensitive material, the temperature of the image forming solvent, and the surface temperature of the heat developing drum. That is, the exposure amount, the temperature of the image forming solvent, and the surface temperature of the heat developing drum when exposing the image to the photosensitive material are parameters of the density of the image formed on the image receiving paper. The control means calculates at least one optimum value of these parameters. This optimum value is calculated based on the temperature and humidity detected by the temperature and humidity detecting means, and when the temperature and humidity change, the calculated optimum value also changes accordingly. That is, at least one of the optimum values of the exposure amount of the image, the temperature of the image forming solvent, and the surface temperature of the heat developing drum, which affects the density of the image, is set on the image receiving paper by changing the temperature and humidity in the image forming apparatus. It is required to cancel the density deviation occurring in the formed image. Also,
The control means controls at least one of the exposure amount of the image, the temperature of the image forming solvent, and the surface temperature of the heat developing drum so as to be the optimum value calculated by the calculation means.

With this, at least one of the exposure amount of the image, the temperature of the image forming solvent, and the surface temperature of the heat developing drum is automatically adjusted according to the temperature and humidity changes in the image forming apparatus. It is possible to correct a density deviation caused by a change in temperature and humidity without performing calibration again.

According to a second aspect of the present invention, in the first aspect of the invention, the control means sets one of the plurality of parameters with respect to the density of an image formed on the image receiving material. The parameter selected with a change in temperature or humidity in the device so as to offset a change in image density formed on the image receiving material caused by a change in temperature or humidity in the device. It is characterized in that the optimum value for the density is calculated again.

According to the second aspect of the present invention, in the control means, the exposure amount when exposing the image to the photosensitive material, the temperature of the image forming solvent, and the temperature, which are parameters of the density of the image formed on the image receiving paper, One of the surface temperatures of the thermal developing drum is selected. Density of an image formed on the image receiving material,
The correlation with the selected parameter can be measured and obtained in advance.

The control means calculates an optimum value of the selected parameter based on the temperature and humidity in the image forming apparatus detected by the temperature detecting means and the humidity detecting means. That is, the calculated optimum value changes with the change in temperature and humidity in the image forming apparatus, and is determined so as to cancel out the density deviation generated in the image formed on the image receiving paper due to the change in temperature and humidity.

According to the calculated optimal value, one of the exposure amount, the temperature of the image forming solvent, and the surface temperature of the heat developing drum when exposing the image to the photosensitive material selected as the parameter is controlled. That is, with the temperature and humidity changes in the image forming apparatus, one of the exposure amount of the image, the temperature of the image forming solvent, and the surface temperature of the heat developing drum is changed to the image formed on the image receiving paper due to the temperature and humidity changes. It is automatically adjusted to offset the resulting density shift. Thus, even if the temperature and humidity in the image forming apparatus change, the density deviation can be corrected without performing the calibration again.

According to a third aspect of the present invention, in the first or second aspect, the control means detects a heating means for heating the heat developing drum and a surface temperature of the heat developing drum. Drum temperature detecting means,
By recalculating the optimum temperature of the heat developing drum according to the change of the temperature or humidity in the apparatus, and controlling the output of the heating means based on the detection result by the drum temperature detecting means, the heat development The temperature is controlled so that the surface temperature of the drum becomes the calculated optimum temperature.

According to the third aspect of the present invention, the heat developing drum is heated by the heating means, and the temperature is detected by the drum temperature detecting means. The controller recalculates the optimum value of the surface temperature of the heat developing drum according to the change in the temperature or humidity in the image forming apparatus. Further, the control means includes:
Based on the temperature detected by the drum temperature detecting means,
The output of the heating means is controlled so that the temperature of the thermal developing drum is controlled to an optimum temperature. That is, the surface temperature of the heat developing drum is automatically adjusted according to the temperature and humidity changes in the image forming apparatus.

As described above, it is possible to provide a heat developing apparatus which automatically corrects the density according to the environment and has excellent density reproducibility and stability.

[0024]

FIG. 1 shows an image forming apparatus 14 according to a first embodiment.

The image forming apparatus 14 includes the image exposing device 10 and the heat developing device 12.

The image exposure apparatus 10 includes a photosensitive material loading section 18.
, A correction circuit 20, a correction data creation unit 22, an exposure unit 24, a temperature sensor 36A, a humidity sensor 36B
It is comprised including. Further, the thermal developing device 12
A face section 26, a heat developing unit 28, a photosensitive material winding section 30, an image receiving / feeding section 32, and a color measuring sensor 34
It is comprised including.

The photosensitive material loading section 18 of the image exposure apparatus 10 is loaded with the photosensitive material 16 wound around a winding shaft 38. The photosensitive material 16 loaded in the photosensitive material loading section 18 is transported in a predetermined direction by driving a transport roller (not shown).

The sensitivity of the photosensitive material 16 varies depending on the temperature and humidity. A temperature sensor 36A for measuring the temperature and a relative humidity (hereinafter, referred to as a sensor) are provided below the photosensitive material loading section 18.
A humidity sensor 36B for measuring the humidity (hereinafter simply referred to as "humidity") is attached. The temperature and humidity of the photosensitive material 16 (hereinafter, referred to as “temperature and humidity”) by the temperature sensor 36A and the humidity sensor 36B.
(Referred to collectively as "temperature and humidity") is constantly monitored.

Temperature sensor 36A and humidity sensor 36B
Are connected to the correction data creation unit 22. The output end of the color measurement sensor 34 provided in the heat developing device 12 is also connected to the correction data creation unit 22. The color measurement sensor 34 is a sensor that measures the color of an image recorded on the image receiving paper 40 that has been thermally developed by the thermal development unit 28. Therefore, the correction data creation unit 22
Based on the detection (measurement) data obtained by 6A, the humidity sensor 36B and the color measurement sensor 34, correction data used for correcting the image data is created.

The output of the correction data generator 22 is connected to a correction circuit 20 to which image data is input. The correction circuit 20 corrects the input image data using the correction data. The output of the correction circuit 20 is
The exposure unit 24 receives the corrected image data (hereinafter referred to as “corrected image data”).

The exposure unit 24 is disposed downstream of the photosensitive material loading section 18 in the transport direction of the photosensitive material 16. That is, the exposure unit 24 is instructed to drive a laser (not shown) based on the corrected image data, and scans the photosensitive material 16 with a light beam to perform exposure. The exposure unit 24 has a center angle of about 1
An 80 ° arc-shaped drum 78 is provided, and the photosensitive material 16 is wound and conveyed along the inner peripheral surface of the drum 78, and a light beam is applied to the photosensitive material 16 from the inner peripheral direction of the drum 78. (So-called inner spinner type).

Next, details of the internal structure of the heat developing device 12 provided adjacent to the image exposure device 10 will be described with reference to FIG.

As shown in FIG. 2, a face portion 26 is provided in the vicinity of a connection portion between the heat developing device 12 and the image exposure device 10. A branch guide (not shown) operated by a solenoid is disposed on the face portion 26. The branch guide is switched between a horizontal state and a vertical state. When the branch guide is switched to the vertical state, as shown by the imaginary line in FIG.
During this time, the photosensitive material 16 can be loosened. Thereby, a speed difference between the processing speed of the heat developing device 12 and the processing speed of the image exposure device 10 can be absorbed. The driving of the transport roller 42 is controlled by a control unit 94 provided below the thermal developing device 12.

Below the face section 26, an image receiving / feeding section 32 is provided. Image receiving paper 40 wound around a take-up shaft 44 is loaded in the image receiving and feeding unit 32, and is transported by a transport roller 42 in a predetermined direction.

A thermal developing unit 28 is provided downstream of the photosensitive material 16 in the transport direction. Thermal development unit 28
Is provided with a water application section 80 in which the photosensitive material 16 is filled with water as a solvent for image formation.

The water application section 80 is supplied with water by a pump 81 from a water tank 82 provided below the thermal developing device 12. By coating the photosensitive material 16 with water, the adhesion when the image receiving paper 40 and the photosensitive material 16 are bonded to each other can be improved.

The heat developing unit 28 is provided with a heat developing drum 84 in addition to the water application section 80. A heater 100 is housed in the center of the thermal developing drum 84. That is, the heat developing drum 84 is heated by the heater 100. (The details of the heat development drum will be described later.) Thereby, the photosensitive material 16 and the image receiving paper 40 conveyed along the outer peripheral surface of the heat development drum 84 are heated for a predetermined time (that is, the heat development processing is performed). To form an image on the image receiving paper 40. A slip prevention belt 86 is provided near the outer periphery of the heat developing drum 84 to prevent the photosensitive material 16 conveyed along the outer circumferential surface of the heat developing drum 84 from being shifted from the image receiving paper 40, so that an image is received on the image receiving paper 84. Care has been taken to form them accurately at 40.

On the downstream side of the thermal developing drum 84 in the transport direction of the photosensitive material 16 and the image receiving paper 40, a photosensitive material peeling member 88 for peeling off the photosensitive material 16 bonded to the image receiving paper 40, and the image receiving paper 40. Is provided with a separating member 90 for an image receiving paper for separating the sheet from the heat developing drum 84.

The image receiving paper 4 is separated by the photosensitive material separating member 88.
The photosensitive material 16 that has been peeled off is wound around a winding shaft 92 provided in the photosensitive material winding section 30, and is disposed as waste material. The color measuring sensor 34 is disposed on the downstream side in the transport direction of the image receiving paper 40 on which an image is formed by being separated from the thermal developing drum 84 by the image receiving paper separating member 90.
The color measurement sensor 34 measures the color of the image formed on the image receiving paper 40, and outputs the measurement data to the correction data creation unit 22 provided in the image exposure device 10. The image receiving paper 40 whose color has been measured by the color measurement sensor 34 is supplied to the heat developing device 1.
2 to the outside.

Next, the heat developing drum 84 will be described with reference to FIG.

A temperature sensor 122 for measuring the temperature is mounted on the surface of the heat developing drum 84 and at the center in the width direction. The type of the temperature sensor 122 is not particularly limited as long as it measures temperature, such as a thermocouple or a thermistor. This temperature sensor 122 is connected to the temperature controller 102.
It is connected to the. In addition, the temperature controller 102 includes:
The aforementioned temperature sensor 36A and humidity sensor 36B are also connected.

The heater 100 provided inside the heat developing drum 84 is connected to an AC power supply 106 for supplying an AC voltage of 200V. That is, the heater 100 heats the thermal developing drum 84 by being supplied with electric power from the AC power supply 106. The heater 100 and the AC power supply 106
Between them, an SSR (Solid-Stade Relay) 104 is installed, and the SSR 104 is also connected to the temperature controller 102.

The SSR 104 becomes conductive only while a predetermined signal is being input from the temperature controller 102.
Power is supplied to the heater 100. That is, the ON / OFF of the heater 100 can be switched by switching the conductive state and the non-conductive state of the SSR 104 by the temperature controller 102. Further, by switching between the conducting state and the non-conducting state within a very short time (the cycle level of the AC power supply), the power supplied to the heater 100 can be changed. Thus, the surface temperature of the heat developing drum 84 is controlled.

Next, the temperature controller 102 will be described with reference to FIG.

The temperature controller 102 has a built-in microcomputer inside, and the microcomputer includes an I / O port 110, a CPU,
114, a RAM 112, and a ROM 110. These I / O port 110, CPU 114, RAM 11
2. ROM 110 is connected to each other by bus 118.

The input side of the I / O port 110 is connected to the temperature / humidity sensor 36 and the temperature sensor 122. Therefore, the surface temperature of the heat developing drum 84 measured by the temperature sensor 122 and the temperature and humidity near the photosensitive material loading unit 18 measured by the temperature sensor 36A and the humidity sensor 36B are input to the temperature controller 102. The surface temperature of the heat developing drum 84 and the temperature and humidity near the photosensitive material loading section 18 are stored in the RAM 112 as needed. On the other hand, on the output side of the I / O port 110, the SS
R104 is connected.

The ROM 116 stores the temperature and humidity environment in which the photosensitive material 16 is placed, and the surface temperature of the heat developing drum 84 for accurately reproducing the density (hereinafter referred to as "optimum temperature").
Are obtained and stored in advance.

The correlation function is determined by the relationship between the temperature and humidity and the density of the image formed by the image forming process.
The relationship between the surface temperature of the image and the density of the image formed by the image forming process is measured and obtained in advance, and is calculated from these relationships. With this correlation function, the surface temperature of the heat developing drum 84 that accurately reproduces the density in the temperature and humidity environment where the photosensitive material 16 is placed (hereinafter, referred to as “optimum temperature”) can be obtained.

Here, in order to specifically explain the correlation function, the vertical axis represents the relationship between the temperature and humidity measured in advance and the density of the image formed by the image forming process in FIG. The density and the temperature and humidity are plotted on the horizontal axis.
MM on the horizontal axis is standard temperature and humidity, LL is low temperature and low humidity, H
H indicates high temperature and high humidity. As can be seen from FIG. 5, the lower the temperature and humidity, the lower the density of the formed image, and the higher the temperature and humidity, the higher the density of the formed image. That is, the sensitivity of the photosensitive material 16 decreases as the temperature and humidity decrease,
The higher the temperature and humidity, the higher the sensitivity. FIG. 6A shows the relationship between the surface temperature of the heat developing drum 84 measured in advance and the density of the image formed by the image forming process, where the vertical axis represents the temperature of the heat developing drum 84 and the horizontal axis. The image density is shown in FIG. As can be seen from FIG. 6A, the higher the density of the heat developing drum 84, the higher the density of the image formed.

Therefore, the relationship between the temperature and humidity and the concentration is as follows:
In the correlation function obtained from the relationship between the surface temperature and the density of the thermal developing drum 84, the lower the temperature and humidity, the higher the optimum temperature is calculated. In addition, the higher the temperature and humidity, the lower the optimum temperature is calculated.

The ROM 116 has five control functions A and P for controlling the surface temperature of the heat developing drum by PID.
B, C, D, and E are also stored. This control function A,
B, C, D, and E represent the temperature change of the heat developing drum 84 when the heat developing device 12 is started up, when the heat developing process is started, when the heat developing process is started, when the temperature drop due to the heat developing process is restored, and when overshoot is prevented. This is a control function corresponding to the pattern. Further, the ROM 116 has control functions A, B,
These temperature change patterns corresponding to C, D, and E are also stored.

The CPU 114 obtains the optimum temperature of the heat developing drum 84 at the temperature and humidity measured by the temperature and humidity sensor 36 according to the correlation function stored in the ROM 16.

The CPU 114 calculates a temperature change of the heat developing drum 84 from the surface temperature of the heat developing drum 84 measured by the temperature sensor 122. The CPU 11
Reference numeral 4 denotes when the developing device whose temperature change is stored in the ROM 116 is started (see AA in FIG. 5), during standby (see BB in FIG. 5), when thermal development processing is started (see CC in FIG. 5), When the temperature drop due to the heat development process is restored (DD in FIG. 5)
When the overshoot is prevented (see EE in FIG. 5), it is determined which temperature change pattern corresponds, and a control function corresponding to the temperature change pattern is selected from control functions A, B, C, D, and E. . This selection is made in advance when the thermal development process is performed continuously after the standby, and the selection order is determined in advance (for example, A → B → C → D → E → B → C → D → E → B → C → D
→ E ...), it is also possible to select according to the selection order. The CPU 114 outputs a signal to the SSR 104 according to the control function.

The operation of the embodiment of the present invention will be described.

First, the flow of the image forming process by the image forming apparatus 14 will be described.

In the image exposure apparatus 10, the photosensitive material 16 loaded in the photosensitive material loading section 18 is sent to the exposure unit 24 by driving a transport roller (not shown). The exposure unit 24 scans and exposes the photosensitive material 16 with a light beam based on the corrected image data. That is,
The exposure unit 24 is provided with an arc-shaped drum 78 having a center angle of about 180 °.
The light beam is irradiated onto the photosensitive material 16 from the inner circumferential direction of the drum 78.

The photosensitive material 16 is provided on a face 26 provided near a connection between the heat developing device 12 and the image exposing device 10.
The water is applied to the photosensitive material by a water application unit 80 belonging to the heat development unit 28, and is sent to the heat development drum 84.

The photosensitive material 16 conveyed along the outer peripheral surface of the heat developing drum 84 at a temperature suitable for the heat developing process.
Then, the image receiving paper 40 is heated for a predetermined time, and an image is formed on the image receiving paper 40.

The image receiving paper 4 is separated by the photosensitive material separating member 88.
The photosensitive material 16 that has been peeled off from the photosensitive material 16 is wound around the winding shaft 92 of the photosensitive material winding section 30, and is disposed as waste material. Further, the toner image is peeled off from the thermal developing drum 84 by the image receiving paper peeling member 90 and discharged to the outside of the thermal developing device 12.

Next, the control flow of the heat developing drum will be described.

When the power of the image forming apparatus 14 is turned on,
The power of the image exposure device 10 and the heat development device 12 is turned on.

Temperature sensor 36A and humidity sensor 36B
Of the temperature and humidity near the photosensitive material loading section 18 is started. The temperature controller 102 receives the temperature and humidity,
From the correlation function between the density and the optimum temperature stored in 116, the optimum temperature of the heat developing drum 84 at the temperature and humidity is obtained. The temperature and humidity measurement by the temperature sensor 36A and the humidity sensor 36B is always performed while the image forming apparatus 14 is ON.

In the thermal developing device 12, the measurement of the surface temperature of the thermal developing drum 84 by the temperature sensor 122 is started.
In response to this, the temperature controller 102 determines that the thermal developing device 12 is being started, and controls the output of the heater 100 using the control function A at the time of starting. This control function A
, The thermal developing drum 84 is quickly heated to the optimum temperature.

When the temperature of the heat developing drum 84 reaches the optimum temperature,
The thermal developing device 12 enters a standby state. Further, in the temperature controller 102, when it is determined from the temperature from the temperature sensor 122 and the temperature change obtained therefrom that the apparatus is in the standby state, the control function for controlling the output of the heater 100 is changed to the control function B in the standby state. Switch automatically.
By the control using the control function B, the heat developing drum 84
Is maintained at an optimum temperature. In the standby state, the above-described image forming process by the image forming apparatus 14 becomes possible.

When the image forming process is started and the thermal developing process is performed, the photosensitive material 16 having a temperature lower than the optimum temperature and the image receiving paper 40 come into contact with the thermal developing drum 84. As a result, the surface temperature of the heat developing drum 84 decreases. When this temperature change is detected by measuring the surface temperature of the heat developing drum 84 by the temperature sensor 122, the temperature controller 102 determines that the heat developing process has been started. Accordingly, the temperature controller 102 automatically switches the control function for limiting the output of the heater 100 to the control function C at the start of the heat development processing. By the control using the control function C, the control is performed so as to prevent the surface temperature of the thermal developing drum 84 from lowering.

Thereafter, the control using the control function C starts to take effect, and the surface temperature of the heat developing drum 84 starts to rise. When this temperature change is detected by measuring the surface temperature of the heat developing drum 84 by the temperature sensor 122, the temperature controller 10
In 2, it is determined that the return of the temperature drop due to the heat development processing has started. Accordingly, in the temperature controller 102, the heater 1
The control function for controlling the output of 00 is automatically switched to the control function D at the time of recovery from the temperature decrease due to the heat development processing. By the control using the control function D, the surface temperature of the thermal developing drum 84 is controlled so as to return to the optimum temperature.

When the surface temperature of the heat development drum 84 becomes equal to or higher than the optimum temperature and the temperature change is detected by measuring the surface temperature of the heat development drum 84 by the temperature sensor 122,
The temperature controller 102 determines that overshoot has occurred. Accordingly, in the temperature controller 102, the heater 10
The control function for controlling the output of 0 is automatically switched to the control function E for overshoot. By the control using the control function E, the surface temperature of the heat developing drum 84 is controlled so as to decrease to the optimum temperature.

When the surface temperature of the heat developing drum 84 falls to the optimum temperature, the standby state is again established, the control is switched to the control by the control function B at the time of standby, and the same control as described above is repeated.

During the temperature control of the heat developing drum (that is, while the image forming apparatus 14 is operating), the environment inside the image forming apparatus 14, that is, the temperature and humidity inside the image forming apparatus 14 may change. Since the sensitivity of the photosensitive material 16 changes depending on the temperature and humidity and the density of the formed image changes, the temperature controller 112 detects the change in temperature and humidity by the temperature sensor 36A and the humidity sensor 36B. The optimum temperature of the heat developing drum 84 is calculated again from the correlation function of the optimum temperature. Subsequent temperature control is performed using the newly calculated optimum temperature. That is, by changing the surface temperature of the thermal developing drum 84 on which the density of the image depends in accordance with the change in temperature and humidity, the occurrence of density deviation is prevented.

For example, when the temperature and humidity in the image forming apparatus 14 decrease and the temperature sensor 36A and the humidity sensor 36B detect the decrease in the temperature and humidity, the temperature controller 112 recalculates the optimum temperature to be higher. In addition, the temperature controller 112
The control function for controlling the output of the heater 100 is automatically switched to the control function A at the time of starting. This switching is
If the thermal development process is being performed by the thermal development drum, the process is performed after the thermal development process is completed. By the control using the control function A, the heat development drum 84 is heated until the temperature of the heat development drum 84 becomes the newly calculated optimum temperature. When the thermal developing drum 84 reaches the newly calculated optimum temperature, the thermal developing device 12 enters a standby state.

When the temperature and humidity in the image forming apparatus 14 rise and the temperature sensor 36A and the humidity sensor 36B detect an increase in the temperature and humidity, the temperature controller 112 recalculates the optimum temperature to be lower. Further, the temperature controller 112 automatically switches the control function for controlling the output of the heater 100 to the control function E for overshoot. Note that this switching is also performed during the thermal development processing by the thermal development drum.
It is performed after the completion of the heat development processing. By the control using the control function E, the temperature of the thermal developing drum 84 is controlled so as to decrease to the newly calculated optimum temperature. When the temperature of the heat developing drum 84 drops to the newly calculated optimum temperature, the heat developing device 12 enters a standby state.

As described above, in this embodiment, since the temperature of the heat developing drum 84 is adjusted in accordance with the change in temperature and humidity, it is possible to prevent the density deviation of the formed image without performing the calibration again. Can be.

In this embodiment, the heat developing drum 8
By adjusting the optimum temperature of No. 4, the image density deviation caused by the change in temperature and humidity was eliminated, but the present invention is not limited to this. Since the density of the image also depends on the temperature of the water to be applied and the amount of exposure, these may be adjusted according to changes in temperature and humidity.

Specifically, the relationship between the temperature of the water to be applied and the density of the image to be formed as shown in FIG. 6B is obtained by measuring the relationship between the density and the temperature and humidity shown in FIG. From the relationship, the correlation between the temperature and humidity and the optimum temperature of the water to be applied is obtained. From this correlation, the optimum temperature of the water to be applied corresponding to the temperature and humidity measured by the temperature sensor 36A and the humidity sensor 36B may be calculated, and the temperature of the water stored in the water application unit 80 may be controlled to that temperature. .

Further, the relationship between the exposure amount and the density of the image to be formed as shown in FIG. 6C is obtained by measurement, and from the relationship between the density and the temperature and humidity shown in FIG. And the optimal exposure amount. From this correlation, an optimal exposure amount corresponding to the temperature and humidity measured by the temperature sensor 36A and the humidity sensor 36B may be calculated, and the exposure amount may be controlled so that the photosensitive material 16 is exposed at the exposure amount. The control of the exposure amount may be performed by changing the intensity of the light beam irradiated on the photosensitive material, or by changing the irradiation time (exposure time). Further, the corrected image data to be exposed may be corrected in advance in accordance with the temperature and the humidity. In this case, the correction data created by the correction data creation unit 22 is newly corrected so as to have this exposure amount.

In this embodiment, five control functions A, B, C, D and E are used, and the five control functions A, B, C, D and
The temperature of the thermal developing drum 84 is controlled by switching E, but is not limited to this. For example, when using a heat developing drum made of a material having a large heat capacity, the number of control functions may be reduced.

Although one heater 100 is used to heat the heat developing drum 84, the invention is not limited to this. A plurality of heaters may be used. For example, in order to extend the life of the heater 100, a plurality of heaters for heating the thermal developing drum 84 may be provided, and outputs of these heaters may be collectively controlled in the same manner as described above.

The temperature controller 102 and the SSR 10
4, the power supplied to the heater 100 is controlled. However, the control is not limited to this as long as the power supplied from the AC power supply 106 to the heater 100 is controlled in accordance with the temperature of the thermal developing drum 84. For example, the power supplied from the AC power supply 106 to the heater 100 may be controlled using a triac circuit instead of the SSR 104.

[0079]

As described above, according to the present invention, it is possible to provide a heat developing apparatus which automatically corrects the density according to the environment and has excellent density reproducibility and stability.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating an internal configuration of an image forming apparatus according to an embodiment.

FIG. 2 is a configuration diagram illustrating a detailed configuration of a heat development device according to the exemplary embodiment.

FIG. 3 is a configuration diagram illustrating a detailed configuration of a heat development drum according to the exemplary embodiment.

FIG. 4 is a block diagram of a temperature controller according to the present embodiment.

FIG. 5 shows a change characteristic of the density of a formed image depending on temperature and humidity.

6A and 6B show density characteristics of an image to be formed, wherein FIG. 6A shows the relationship between the surface temperature of the heat developing drum and the density, FIG. 6B shows the relationship between the temperature of the applied water and the density, and FIG. The relationship of density is shown.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Image exposure apparatus 12 Thermal developing apparatus 14 Image forming apparatus 24 Exposure unit 36A Temperature sensor (temperature detection means) 36B Humidity sensor (humidity detection means) 80 Water application part (application tank) 84 Heat development drum 100 Heater (heating means) 102 Temperature controller (control means) 104 SSR 122 sensor (drum temperature detecting means)

Claims (3)

[Claims] An image is exposed by irradiating a light beam to a photosensitive material, and the photosensitive material or the image receiving material is immersed in a coating tank in which an image forming solvent is stored, and the image forming solvent is applied. Laminating the photosensitive material and the image receiving material,
In an image forming apparatus which performs a heat development process by contacting the surface of a heat developing drum heated to a predetermined temperature by a heating means to form an image on an image receiving material, and detects a temperature in the apparatus. Means, a humidity detecting means for detecting humidity in the apparatus, and an amount of exposure of the photosensitive material, stored in the coating tank, based on a result of temperature and humidity detection by the temperature detecting means and the humidity detecting means. Calculating the optimum value of at least one of a plurality of parameters of the temperature of the image forming solvent and the surface temperature of the thermal developing drum, and according to the optimum value, the exposure amount, the temperature of the image forming solvent, and Control means for controlling at least one of the surface temperatures of the heat developing drum. 2. The image receiving apparatus according to claim 2, wherein the controller selects one of the plurality of parameters for the density of an image formed on the image receiving material, and the image receiving apparatus is caused by a change in temperature or humidity in the apparatus. An optimal value for the density of the parameter selected according to a change in temperature or humidity in the apparatus is recalculated so as to cancel a change in density of an image formed on the material. 2. The image forming apparatus according to 1. 3. The apparatus according to claim 2, wherein the control unit includes a heating unit configured to heat the thermal developing drum, and a drum temperature detecting unit configured to detect a surface temperature of the thermal developing drum. By recalculating the optimum temperature of the heat developing drum in accordance with and controlling the output of the heating means based on the detection result by the drum temperature detecting means, the surface temperature of the heat developing drum is calculated. 3. The image forming apparatus according to claim 1, wherein the temperature is controlled so as to be an optimum temperature.