JPH075591A - Image recorder - Google Patents

Abstract

PURPOSE:To prevent fluctuations in the quality of an image regardless of the fluctuations in the photosensitive characteristic of a photosensitive material. CONSTITUTION:In an image recorder exposing an image on the photosensitive material which has sensitivity with respect to light in an infrared ray area and whose photosensitive characteristic is at least changed by variation in temperature, an atmospheric temp. around the carrying path of time photosensitive material reaching an exposing part from a photosensitive material magazine is detected by a temp. sensor 34 and the temp. of a guide coming into contact with the photosensitive material on the exposing part is detected by a temp. sensor 32, as well. In a ROM 264, a table displaying the relation between the temperatures detected by the temp. sensors 32 and 34 and a correction value for correcting the change in the photosensitive characteristic of the photosensitive material is stored. In a control part 248 connected to the temp. sensors 32 and 34 via A/D converters 262 and 264, the value of a driving current supplied to semiconductor lasers 442a, 442b and 442c is changed based on the temperatures detected by the temp. sensors and the table.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording apparatus, and in particular, it records an image by exposing a light-sensitive material having at least one infrared-sensitive layer sensitive to light in the infrared region to light in the infrared region. The present invention relates to an image recording device.

[0002]

2. Description of the Related Art Conventionally, as a light-sensitive material sensitive to light in the infrared region, for example, a color light-sensitive material described in Japanese Patent Publication No. 62-15835 by the present applicant has been known. As an example of an image recording apparatus for recording an image using this type of light-sensitive material, Japanese Patent Application Laid-Open No. 1-97939 and the like of the present applicant use two types of recording materials, for example, a light-sensitive material and an image-receiving material. An image recording device for recording an image is described.

In this type of image recording apparatus, the light-sensitive material and the image-receiving material are wound in rolls and housed in magazines of which the inside is in a light-shielded state. Used by pulling out. The photosensitive material cut out by pulling out a predetermined size from the magazine is
The image is exposed by being sent to the exposure unit. In this image exposure, sub-scanning is performed by sandwiching and transporting a photosensitive material by transport rollers, and an infrared light beam emitted from a light source such as a semiconductor laser is modulated according to the image, and a deflecting means such as a polygon mirror is used. By scanning along the main scanning direction and irradiating the photosensitive material.

The light-sensitive material on which the image has been exposed is sent to the heat-development transfer section after the solvent for image formation is applied in the water application section. In the heat-development transfer section, the photosensitive material coated with the solvent and the image-receiving material drawn out by a predetermined size from the magazine are superposed and wound so as to be closely attached to the outer periphery of the heating drum. As a result, the photosensitive material is thermally developed and at the same time an image is transferred to the image receiving material, and an image is formed (recorded) on the image receiving material.

[0005]

By the way, a light-sensitive material having sensitivity in the infrared region, for example, Japanese Patent Application No. 5-10 filed by the present applicant.
The silver halide color photographic light-sensitive material having at least one infrared-sensitive silver halide emulsion layer shown in No. 6229 shows that the temperature and humidity during exposure depend on the type of emulsion, depending on the type of emulsion. Accordingly, it has been found that the photosensitive characteristics such as sensitivity and color balance change, and the sensitivity increases as the temperature increases, for example. On the other hand, the internal environment (temperature and humidity) of the image recording apparatus is not constant, and for example, a heating drum or the like for developing the photosensitive material serves as a heat source, and the temperature or the like fluctuates over time.

For this reason, the photosensitive material drawn out from the magazine has its photosensitive characteristics changed under the influence of temperature and humidity fluctuations in the conveying path to the exposure section and in the exposure section. Since the density and color balance of the transferred image also fluctuate, there is a problem that an image with a constant image quality cannot be obtained. The same problem also occurs in an image recording apparatus that develops an exposed photosensitive material to form an image on the photosensitive material without transferring the image to the image receiving material.

The present invention has been made in consideration of the above facts, and an object of the present invention is to obtain an image recording apparatus capable of preventing the image quality from fluctuating irrespective of the fluctuation of the photosensitive characteristics of the photosensitive material.

[0008]

In order to achieve the above object, an image recording apparatus according to the present invention has at least one infrared-sensitive layer sensitive to light in the infrared region, and at least one of temperature and humidity. Conveying means for conveying the photosensitive material whose photosensitive characteristics change due to the change to the exposure position, light beam emitting means for emitting a light beam in the infrared region, and conveying to the exposure position by the light beam emitted from the light beam emitting means. An exposure unit that scans and exposes an image on the formed photosensitive material; a detection unit that detects at least one of temperature and humidity around at least one of the exposure position and the periphery of the photosensitive material conveying path to the exposure position; Based on at least one of the detected temperature and humidity, the photosensitive material in the exposure section is corrected so that the change in the photosensitive characteristic of the photosensitive material is corrected. It is configured to include an exposure amount control means for controlling the amount of exposure.

[0009]

As described above, the photosensitive characteristics of a photosensitive material having at least one infrared photosensitive layer sensitive to light in the infrared range fluctuates under the influence of temperature and humidity, and the photosensitive characteristics during exposure of an image are affected. The image quality also changes according to the change in the photosensitive characteristics of the material. Here, it is assumed that the photosensitive characteristics of the photosensitive material when exposing an image mainly depend on the temperature and humidity around the exposure position and around the transport path of the photosensitive material reaching the exposure position. Therefore, in the present invention, at least one of the temperature and the humidity in at least one of the periphery of the exposure position and the periphery of the conveyance path of the photosensitive material reaching the exposure position is detected, and the photosensitive material is exposed to light based on at least one of the detected temperature and humidity. The exposure amount of the light-sensitive material by the light beam is controlled so that the change in the characteristics is corrected.

The photosensitivity of the photosensitive material includes the sensitivity and color balance of the photosensitive material. Further, the exposure amount control means controls the exposure amount, for example, by exposing the image by scanning the light beam and changing the power or irradiation time of the light beam when exposing each pixel according to the density of each pixel. In this case, the power or irradiation time of the light beam may be changed as a whole. It is also possible to provide an optical element having a controllable transmittance or reflectance on the optical path of the light beam and change the transmittance or reflectance of the optical element.

As a result, even if the photosensitive characteristics of the photosensitive material change due to changes in temperature and humidity around the exposure position and around the conveying path of the photosensitive material reaching the exposure position,
Since the exposure amount is corrected and corrected, the image quality is prevented from fluctuating.

[0012]

Embodiments of the present invention will now be described in detail with reference to the drawings. In addition, although the following description will be given using numerical values that do not hinder the present invention, the present invention is not limited to the numerical values described below. First, a schematic configuration of the image recording apparatus according to this embodiment will be described.

(Schematic Configuration of Image Recording Apparatus) As shown in FIG. 1, the image recording apparatus 10 is formed in a box shape as a whole, and a machine base 12 is provided with a front door 13 and a side door 15. And an upper cover 11 is attached on the upper side. By opening each door, the inside of the machine base 12 is exposed. Although not shown, each door is equipped with a safety device based on a so-called interlock mechanism, so that the power supply to a predetermined portion is cut off at the same time when the door is opened. As shown in FIG. 2, in the image recording apparatus 10, the photosensitive material magazine 14 that stores the photosensitive material 16 is used.
Is set, the nip roller 18 is operated and the photosensitive material 16 is pulled out by the nip roller 18. When the photosensitive material 16 is pulled out by a predetermined length, the cutter 20 operates and the photosensitive material 16 is cut into a predetermined length.

As the light-sensitive material 16, a heat-developable color comprising a combination of a red light-sensitive layer, a first infrared light-sensitive layer and a second infrared light-sensitive layer described in Japanese Patent Application No. 5-106229 filed by the present applicant. A light-sensitive material can be used.

Photosensitive material 1 cut by cutter 20
6 is inverted while being conveyed by the conveying rollers 19, 21, 23, 24, and 26, and is conveyed to the exposure unit 22 with its photosensitive (exposure) surface facing upward. When the photosensitive material 16 is nipped by the conveying roller 23, the driving of the conveying roller 23 is temporarily stopped, and the photosensitive material 16 is in a standby state immediately before the exposure unit 22. Then, the conveyance rollers 23 and 24 are started to be driven, and the photosensitive material 16 passes through the exposure section 22 at a predetermined speed. At the same time when the photosensitive material 16 is conveyed (passes through the exposure unit 22), the exposure device 90 operates and the exposure unit 2
The photosensitive material 16 located at 2 is scanned and exposed. The configuration of the exposure device 90 will be described later.

FIG. 3 shows the photosensitive material magazine 14 to the exposure section 22.
An enlarged view of the transport path leading to and the vicinity of the exposure unit 22 is shown. A guide 30 for guiding the conveyance of the photosensitive material 16 is provided below the conveyance rollers 23 and 24. When the image is exposed in the exposure section 22, the surface (back surface) of the photosensitive material 16 opposite to the emulsion surface is brought into contact with and supported by the guide 30.

A temperature sensor 32 for detecting the temperature of the guide 30 is attached to the guide 30. In addition, a temperature sensor 34 for detecting the ambient temperature around the transport path is also provided in the transport path from the photosensitive material magazine 14 to the exposure section 22.
Is provided. Temperature sensor 32 and temperature sensor 34
Includes a thermosensitive element such as a thermistor and a drive circuit for driving the thermosensitive element, and outputs an analog signal of a voltage level according to the detected temperature.

When the exposure is started, the photosensitive material 16 is sequentially fed to the switchback section 40 from the exposed portion, and after the entire length of the photosensitive material 16 is once accommodated in the switchback section 40, the water is fed by the reverse rotation of the conveying roller 26. It is sent to the coating section 62. In the water application unit 62, the supply roller 66 is driven to feed the photosensitive material 16 between the guide block 70 and the application tank 64 that stores water, apply water (about 11 cc / m ² as an example), and further squeeze. Roller 6
It is nipped and conveyed by 8. The photosensitive material 16 coated with water in the water coating section 62 is sent to the heat development transfer section 104 by the squeeze roller 68.

On the other hand, as the scanning exposure of the photosensitive material 16 is started, the image receiving material 108 is also drawn from the receiving material magazine 106 by the nip roller 110 and conveyed. When the image receiving material 108 is pulled out by a predetermined length, the cutter 112 operates and the image receiving material 108 is cut into a predetermined length. The image receiving material 108 cut by the cutter 112 is conveyed by the conveying rollers 190, 186, 114 while being guided by the guide plate 182 of the image receiving material conveying section 180. The leading end of the image receiving material 108 is the conveying roller 114.
When sandwiched by, the image receiving material 108 is in a standby state immediately before the thermal development transfer section 104.

In the heat development transfer section 104, when it is detected that the squeeze roller 68 has fed the photosensitive material 16 between the outer periphery of the heating drum 116 and the bonding roller 120, the conveyance of the image receiving material 108 is restarted. The heating drum 11 is fed to the laminating roller 120 as well.
6 is activated. A guide plate 122 is provided between the laminating roller 120 and the squeeze roller 68 of the water applying section 62.
Is arranged, and the photosensitive material 16 sent from the squeeze roller 68 is reliably guided to the laminating roller 120. Further, a blade guide 124 is arranged between the bonding roller 120 and the conveying roller 114 for the image receiving material 108, and the image receiving material 108 is also reliably guided to the bonding roller 120.

Here, the image receiving material 108 conveyed to the heat development transfer section 104 is synchronized with the conveyance of the photosensitive material 16, and the laminating roller 12 in a state in which the photosensitive material 16 precedes by a predetermined length.
0 and the heating drum 116 are fed and superposed. The photosensitive material 16 and the image receiving material 108, which are superposed by the laminating roller 120, are sandwiched between the heating drum 116 and the endless pressure contact belt 118 in the superposed state, and approximately ⅔ of the circumference of the heating drum 116 ( It is conveyed over the space between the winding roller 134 and the winding roller 140.

Further, the photosensitive material 16 and the image receiving material 108, which are superposed, are heated by the heating drum 116 and the endless pressure contact belt 11.
8, the heating drum 116 temporarily stops its rotation, which heats the photosensitive material 16 and the image receiving material 108 (for example, a total heating time of 35 seconds,
Average heating temperature 83 ℃). When the photosensitive material 16 is heated during the sandwiching conveyance and at the time of stopping, it releases a movable dye, and at the same time, the dye is transferred to the dye fixing layer of the image receiving material 108 to obtain an image.

After that, when the photosensitive material 16 and the image receiving material 108 are nipped and conveyed and reach the lower portion of the heating drum 116, the peeling claw 154 is moved by the cam 130 and the image receiving material 1
08, the peeling claw 154 engages with the leading end of the photosensitive material 16 that is conveyed by a predetermined length, and peels the leading end of the photosensitive material 16 from the outer periphery of the heating drum 116. Further, the pinch roller (not shown) presses the photosensitive material 16 due to the return movement of the peeling claw 154, whereby the photosensitive material 16 is pressed by the pinch roller while being bent and guided.
It is wound around 42 and moved downward.

The photosensitive material 16 wound around the bending guide roller 142 is conveyed by the sensitive material discharge rollers 158 and 160 while being guided by the guide roller 162.
At this time, it is dried by the drying fan A of the drying unit 50 and accumulated in the waste photosensitive material storage box 178.

On the other hand, the heating drum 1 is separated from the photosensitive material 16.
The image receiving material 108 that moves while being in close contact with 16.
Are sent to the peeling roller 174. When the tip of the image receiving material 108 is nipped by the peeling roller 174 (between the heating drum 116), the peeling claw 1 is again moved by the cam 130.
76 is moved, and the peeling nail 17 is attached to the tip of the image receiving material 108.
6 is engaged and the image receiving material 108 is peeled off from the outer periphery of the heating drum 116.

The image receiving material 108 peeled off from the outer periphery of the heating drum 116 by the peeling claw 176 is further wound around the peeling roller 174 and moved downward, and guided by the material receiving guide 170 while receiving the material receiving rollers 172, 1.
73, 175, and at this time, the drying fan B
And discharged to the tray 177 while being dried by the ceramic heater 210. In this way, the image recording device 1
In the case of 0, the image recording processing of a plurality of sheets is successively performed.

(Outside Air Suction / Exhaust Structure) Next, the image recording apparatus 10
The outside air supply / exhaust structure will be described. As shown in FIG. 2 and FIG. 4, the conveyance guide 300 that constitutes the switchback unit 40 in the upper right portion of the heating drum 116 has a pin 302.
It is rotatably supported by. As a result, the transport guide 300 is set so that the lower surface thereof is pushed up by the push plate 304 to the upper right as the heating drum 116 moves.

Further, the photosensitive material 1 is provided on the transport guide 300.
An elongated hole-shaped guide path 306 for guiding 6 is formed, and the photosensitive material 16 conveyed from the exposure section 22 is guided by the guide path 306.
It is designed to be switched back through. Further, on the upper surface of the transport guide 300, a wind direction changing plate 308 is provided upright in a direction diagonally intersecting the transport direction of the photosensitive material 16. The wind direction changing plate 308 has a trapezoidal shape, and the height of the image recording apparatus 10 standing from the rear side to the front side is increased. As a result, the outside air sucked from the rear side of the image recording device 10 is uniformly reflected to the exposure unit 22 (see FIG. 5). Also, the wind direction changing plate 308
Are reinforced by substantially triangular stays 310 and 312. Further, as shown in FIG. 5, on the left side of the wind direction changing plate 308, an exhaust fan 34 for discharging the heat of the power supply unit to the outside.
0 is provided.

On the other hand, as shown in FIG. 2, an exhaust port 342 for exhausting the inhaled outside air is formed on the right side surface of the exposure section 22. A light shielding cover 344 shown in FIG. 5 is fitted into the exhaust port 342. Further, as shown in FIG. 2, the drying fan A sucks the outside air from the lower surface of the image recording apparatus 10. Dry air is blown onto the photosensitive material 16 and the image receiving material 108 by the drying fan A. This dry air is blocked by the receiving material guide 170 extending in the vertical direction, and the photosensitive material magazine 1
It does not flow to the 4 side. Also, the receiving material guide 1
A ceramic heater 210 as a drying unit is arranged at 70 to accelerate the drying of the conveyed image receiving material 108.

The air flow as described above includes the photosensitive material magazine 14, the conveying portion from the photosensitive material magazine 14 to the exposure portion 22, the exposure portion 22 for exposing the photosensitive material 16, and the exposure portion 22 to the heating drum 116. The temperature difference along the width direction of the photosensitive material 16 (direction orthogonal to the transport direction) in the transport unit up to the developing unit, the water coating unit 62, and each unit of the developing unit is suppressed (for example, within 2 ° C.). ing.

(Structure of Exposure Apparatus) Next, the structure of the exposure apparatus 90 will be described. As shown in FIG. 6, the exposure device 90 includes semiconductor lasers 442a, 442b and 442c, which are connected to a control device 220 (see FIG. 8) described later. As shown in FIG. 8, a semiconductor laser 442
The laser diode 438a includes a laser diode 438a and a photodiode 440a.
a emits a laser beam L1 in the infrared region having a wavelength of about 750 nm in response to a control signal from the control device 220, and the photodiode 440a is a laser diode 43.
The optical output of the laser beam L1 emitted from 8a is detected.

The semiconductor laser 442b is composed of, for example, a laser diode 438b for emitting a laser beam L2 having a wavelength of about 680 nm and a photodiode 440b. The semiconductor laser 442c is, for example, a laser beam having a wavelength of about 810 nm. The semiconductor laser is composed of a laser diode 438c that emits L3 and a photodiode 440c. By irradiating these laser beams L1, L2, and L3, the photosensitive material 16 develops cyan, magenta, and yellow, respectively.

Although not shown, in the present embodiment, the semiconductor lasers 442a, 442b and 442c are press-fitted inside a heat sink made of aluminum. A non-through hole is provided in the vicinity of the semiconductor laser press-fitting portion of the heat sink, and a thermistor as a temperature sensitive element is embedded in the non-through hole. It is fixed to. Further, the power transistor is fixed to the heat sink so that the thermal resistance becomes small.

On the laser beam emission side of the semiconductor laser 442a, there is provided a lens group 444a composed of a collimator lens for converting the laser beam L1 into a substantially parallel light beam and a cylindrical lens for shaping the emitted light beam into a substantially circular shape. Similarly, lens groups 444b and 444c are provided on the laser beam emitting sides of the semiconductor lasers 442b and 442c, respectively.
Is provided. These lens groups 444a and 444
A reflection mirror 446 is provided on the exit side of b and 444c.

The laser beams L1, L2 and L3 reflected by the reflection mirror 446 are incident on the polygon mirror 448. The polygon mirror 448 rotates at a constant speed in the direction of arrow C, and the laser beams L1, L2, and L3 reflected by the polygon mirror 448 pass through the fθ lens 450 and a cylindrical mirror 452 having a surface tilt correction function.
The light is reflected in order at 454 and is main-scanned on the photosensitive material 16 in the arrow A direction. In this way, the laser beam that is mainly scanned by the polygon mirror 448 reaches the exposure unit 22 as slit light. In the exposure unit 22, the photosensitive material 16 is driven by the transport rollers 23 and 24 to move in a direction (arrow B direction) substantially orthogonal to the main scanning direction (arrow A direction).
Be transported to. As a result, an image is formed on the photosensitive material 16. The photosensitive material 16 is conveyed in a direction opposite to the sub-scanning direction.

As described above, the scanning of the laser beam by the rotation of the polygon mirror 448 functions as the main scanning for forming a two-dimensional image, and the transportation of the photosensitive material 16 by the transportation rollers 23 and 24 functions as the sub-scanning. At the position where the laser beam is emitted from the reflection mirror 452 and the laser beam at the end portion of the main scanning by the polygon mirror 448 (end portion in the direction opposite to the arrow A direction in FIG. 6) is incident, the reflection mirror 456 is provided. It is provided. A start point detection sensor 458 is arranged on the laser beam emission side of the reflection mirror 456. As the starting point detection sensor 458, an optical sensor such as a photodiode or CCD sensor, or an IC in which a photodiode, an amplifier and a comparator are integrated is used. The signal output from the starting point detection sensor 458 is used to set the timing when performing the main scanning and the conveyance (sub scanning) of the photosensitive material 16.

As described above, the exposure apparatus 90 uses the different-angle incidence optical system as the optical system, but the present invention is not limited to this, and a dichroic mirror or the like is used to overlap the optical paths of the three laser beams. It is also possible to apply a so-called combining optical system in which light is incident on an optical deflector such as a polygon mirror. Further, instead of the polygon mirror, an optical deflecting means such as a galvanometer mirror or a resonant scanner may be used.

Further, the light quantity of the laser beam applied to the photosensitive material 16 is adjusted by adjusting the lens groups 444a, 444b, 4 and 4.
A light amount attenuation filter is arranged on the exit side of 44c, or λ /
This can be done by disposing two plates and a polarization beam splitter.

The exposure apparatus 90 as described above includes the casing 9
2 (see FIG. 7), and is fixed to the position shown in FIG. 2 inside the upper cover 11 together with the casing 92 via three screws 94. A fan (not shown) is arranged in the vicinity of the position where the exposure device 90 is arranged (obliquely upper right in FIG. 7). The fan is adapted to generate an air flow flowing in the direction of arrow E in FIG. 7 toward the casing 92, and fins 96 are formed in the casing 92 along the flow of the air flow. The air flow generated by the fan is guided by the fins 96 and is guided to the casing 9
2 flows along the direction of arrow E in FIG. This air flow makes the temperature distribution inside the casing 92, that is, the exposure apparatus 90 uniform.

(Control Device) Next, the control device 220 will be described. As shown in FIG. 8, the control device 220 includes a main control unit 242 including a microcomputer and a memory. When the main control unit 242 is conceptually divided into functions, a look-up table 244 for converting 8-bit image data input from another device such as a host computer into 12-bit image data for recording.
And an APC control unit 246 that performs APC control described later.
And a control unit 248 that controls these operations.

The control unit 248 includes an analog digital (A
/ D) the temperature sensor 32 via the converters 262, 264,
34 are connected to each other, and digital data representing the temperatures detected by the temperature sensors 32 and 34 are input. Although not shown in the figure, the thermistor fixed in the through hole of the heat sink is connected to the control unit 248 via an A / D converter, and the power transistor fixed to the heat sink is further connected to the control unit 248. It is connected through a drive circuit for turning on and off the power transistor.

Further, the main controller 242 has a ROM 264.
The ROM 264 has a temperature sensor 3
Temperature detection value by 2, 34 and semiconductor laser 442
The table showing the relationship between the correction values of the drive currents supplied to a, 442b, and 442c is stored in advance. This table adjusts the temperature around the exposure unit 22 and the temperature around the conveyance path of the photosensitive material 16 reaching the exposure unit 22 to a predetermined value, and at that time, the photosensitive material 16 conveyed from the photosensitive material magazine 14 and reached the exposure unit 22. The temperature sensor 3 is set based on the result of repeating the experiment for measuring the surface temperature by changing the temperatures around the exposure section and the transport path to various temperatures.
Corresponding detected values of 2 and 34 and correction values for each color for correcting the variation from the standard value of the photosensitive characteristic calculated by the photosensitive characteristic corresponding to the measured surface temperature of the photosensitive material 16. It was made.

Further, the control device 220 includes the semiconductor laser 4
42a, 442b, 442c corresponding to the pulse width modulation circuits 250, 252, 254 and the laser drive circuit 25.
6, 258 and 260 are provided. The pulse width modulation circuit 250 includes an integration circuit 204 and a digital analog (D /
A) The converter 216 is provided. The clock signal for each pixel output from the main control unit 242 is input to the integration circuit 204, and the 12-bit image data output from the lookup table 244 is input to the D / A converter 216. A comparator 2 is provided at the output end of the integrating circuit 204.
It is connected to one of the two input terminals 06, and the triangular wave signal waveform in which the pixel clock is integrated is output from the integrating circuit 204 to the comparator 206.

The output terminal of the D / A converter 216 is connected to the other of the two input terminals of the comparator 206, and the analog terminal corresponding to the image data input from the D / A converter 216 to the comparator 206 is connected. The signal is output. The output terminal of the comparator 206 is connected to the gate circuit 208. The comparator 206 compares the levels of the two input signals, and outputs a signal that goes high when the level of the signal input from the integrating circuit 204 exceeds the level of the D / A converter 216. Gate circuit 2
The output side of 08 is connected to the laser drive circuit 256. Therefore, a modulated pulse signal whose pulse width is changed (pulse width modulated) according to the density of each pixel of the image data is output to the laser drive circuit 256 via the gate circuit 208. .

Further, the pulse width modulation circuit 250 is provided with a white detection circuit 218, and the image data from the lookup table 244 is also input to the white detection circuit 218. The white detection circuit detects image data corresponding to white in the input image data, and outputs a signal for turning off the gate of the gate circuit 208 while the signal corresponding to this image data is output from the comparator 206. . As a result, the pulse signal output from the gate circuit 208 becomes low level during the period, and the pulse corresponding to the white pixel is removed. The pulse width modulation circuits 252, 2
Since 54 has the same configuration as the pulse width modulation circuit 250, detailed description thereof is omitted.

On the other hand, the laser drive circuit 256 has a D / A converter 406. The D / A converter 406 is connected to the APC control unit 246 of the main control unit 242, and
Drive current control data indicating the level of the drive current of the semiconductor laser 442a is input from the PC control unit 246. D /
The constant current circuit 404 is connected to the A converter 406, and the input drive current control data is converted into an analog signal and output to the constant current circuit 404. Constant current circuit 404
Then, a constant level drive current corresponding to the level of the input analog signal is output.

The modulation circuit 402 is connected to the constant current circuit 404, and the drive current output from the constant current circuit 404 is supplied to the modulation circuit 402. The modulation circuit 402 is connected to the pulse width modulation circuit 250, and is also connected to the cathode of the laser diode 438a of the semiconductor laser 442a. The modulation circuit 402 is the pulse width modulation circuit 25.
The drive current is switched and modulated by a pulse signal input from 0, and the modulated drive current is applied to the semiconductor laser 442a.
Of the laser diode 438a.

As described above, the semiconductor laser 442a is supplied with the drive signal of the level corresponding to the value of the drive current control data. The value of the drive current control data is changed when the APC control unit 246 performs automatic power control (APC control) for emitting a laser beam having a predetermined optical output, and the level of the drive signal is changed in accordance with the change of the value. Will also be changed. This automatic power control is performed while monitoring the optical output by the photodiode 440a incorporated in the semiconductor laser 442a.

The anode of the laser diode 438a is connected to the power supply line via an on-surge countermeasure circuit (not shown). The on-surge countermeasure circuit includes a slow starter circuit having a predetermined time constant including a resistor and a capacitor, and the supply of voltage to the laser diode 438a when the power is turned on is delayed by a time corresponding to the time constant,
A surge current is prevented from flowing through the semiconductor laser 442a. The anode of the laser diode 438a is connected to the anode of the photodiode 440a.

The anode of the photodiode 440a is
The current voltage (I
/ V) conversion circuit 414 and is connected to an A / D converter 416. The A / D converter 416 is the APC control unit 24.
6 and outputs digital data representing the optical output of the laser diode 438a converted and output by the A / D converter 416. The laser drive circuit 25
Nos. 8 and 260 have the same configuration as that of the laser drive circuit 256, and a description thereof will be omitted.

(Operation) Next, the operation of this embodiment will be described.
First, the color misregistration correction, which is one of the setup operations performed before the image recording in the image recording apparatus 10, will be described. The optical system of the exposure device 90 includes a lens group 4
This is a different-angle incidence system in which the optical paths of the laser beams L1, L2, and L3 emitted from 44a, 444b, and 444c form an acute angle so as to approach as they approach the polygon mirror 448. Therefore, the semiconductor lasers 442a, 442b,
When both 442c are turned on at the same time, the laser beams L1 and L
2 and L3 are irradiated onto the photosensitive material 16 at positions separated by a predetermined distance along the main scanning direction.

Therefore, in the image recording apparatus 10, the semiconductor lasers 442a, 442b, 442c are caused to emit light while being shifted by the time corresponding to the predetermined interval, so that the pixel recording positions of the semiconductor lasers 442a, 442b, 442c coincide with each other. I am trying to let you. However,
The distance between the irradiation positions is not constant in each image recording device due to the machine difference of the image recording device 10, and when the recording position of the pixel by each semiconductor laser is deviated, it is visually recognized as a color misregistration of the recorded image. become.

Therefore, when the image recording apparatus 10 is installed, or when color shift occurs due to change over time, the color shift is corrected. Specifically, the semiconductor lasers 442a, 442b, 4 are rotated by rotating the polygon mirror 448.
All 42c are turned on. As a result, the laser beams L1 and L are emitted from the starting point detection sensor 458 at a certain time interval.
The pulse corresponding to 2, L3 is output. The color misregistration is corrected based on the pulse interval.

[0054] As an example, frequency 5MH _z of the pixel clock signal, if there is no color shift of the pulses of the clock signal from the output of the pulse corresponding to the laser beam L1
A pulse corresponding to the laser beam L2 is output when 205 pulses are counted, and a pulse corresponding to the laser beam L3 is output when 400 pulses of the clock signal are counted after the pulse of L1 is further output. To do. Here, after the pulse of L1 is output, L2 is actually output.
If the time until the pulse of is output is 41.1 μsec and the time from the output of the pulse of L1 to the output of the pulse of L3 is 80.05 μsec, L1 → L2 = 41.1 μsec = 205 × 200nsec + 100nsec L1 → L3 = 80.05μsec = 400 × 200nsec + 50nsec, and there are deviations of 100nsec and 50nsec based on L1. In this way, the shift is obtained based on the pulse interval, and the phase of the clock signal for driving the semiconductor lasers 442b and 442c is determined by the semiconductor laser 442a.
The color misregistration can be eliminated by making the difference by the above-mentioned misregistration with reference to the clock signal for driving the.

[0055] As the means for shifting the phase of the clock signal, for example, when the frequency of the reference clock signal of the main control unit 242 is assumed to be 40MH _z, a pixel clock signal with this reference clock signal by dividing (e.g. 5MH _z) after obtaining, 5M by the shift register operating at 40MH _z
The pixel clock signal of H _z is delayed to generate eight kinds of pixel clock signals whose phases are shifted by an integral multiple of 25 nsec.
From these, three types of clock signals with the smallest color shift are selected, and these are input to the corresponding pulse width modulation circuits as pixel clock signals for driving each semiconductor laser. The timing of starting the modulation in each pulse width modulation circuit is obtained by counting the number of pulses of the input pixel clock signal,
Etc.).

On the other hand, when the image recording apparatus 10 is powered on, a bias current supplied from a bias circuit (not shown) flows through the semiconductor lasers 442a, 442b and 442c. Here, when the image data reception is started or the image data reception is ended, or when an image print command is input to the image recording apparatus 10, the "exposure mode" is set (see FIG. 9), and the control unit 248 instructs the APC controller 246 to increase the light output from the laser diodes 438a, 438b, 438c to a predetermined value A ₁ .

[0057] This received by the APC control unit 246 in the laser diode 438a, 438b, so that the optical output 438c is increased to the target value A increases to ₁ or sequentially target value A ₁ one by one, at the same time, the laser driving circuit 256 , 25
8, the value of the drive current control data to be output to 260 is changed every predetermined time. In order to increase the light output to the target value A ₁ , digital data representing the light output detected by the photodiodes 440a, 440b, 440c is taken in via the I / V converter 414 and the A / D converter 416 and taken in. Data is compared with the set value corresponding to the target value A ₁ ,
This is done by increasing the value of the drive current control data until the values are equal.

As described above, the laser diodes 438a, 438b, and 438c are continuously turned on in the exposure mode and before the image is exposed on the photosensitive material 16. During this period, the APC controller 246 takes in digital data representing the optical output of the laser diode at predetermined time intervals and monitors the optical output. If the optical output of each laser diode deviates from the target value A ₁ , the optical output APC control for controlling the magnitude of the drive current of each laser diode is performed so that the target value A ₁ becomes.

The laser diodes 438a, 438
b and 438c increase the optical output of the drive current control data until it reaches a predetermined value A ₁ ;
The amount of change (increase / decrease) in the value of the drive current control data for each predetermined time when controlling the optical outputs of the laser diodes 438a, 438b, 438c to the predetermined value A ₁ may be the same or different. Good. However, it is preferable to make the increment larger than the change (increase / decrease) because the optical output of each laser diode 438a, 438b, 438c reaches the predetermined value A ₁ in a short time. When the optical output of each laser diode reaches a predetermined value A ₁ , the polygon mirror 448 starts rotating.

When the image is exposed, when the laser beam is detected by the starting point detection sensor 458 and a pulse is output, the laser diodes 438a and 438 are temporarily output.
After the lighting of b and 438c is stopped, each laser diode is modulated and lit. In this modulation lighting, the target value of the light output is changed to a target value A ₂ larger than A ₁ , and each laser diode is lit for a predetermined time t ₁ (for example, 100 μsec), during which the light output data of each laser diode is output. Captured sequentially, the optical output of each laser diode is the target value A ₂
If it is out of the range, the APC control is performed to change the drive current control data so as to match the target value A ₂ . Further, the laser diode is turned on for a predetermined time t ₂ (for example, 150 μse
c) Turn off the light.

After turning on / off the laser diode as described above before the laser beam is detected by the start point detection sensor 458, the laser beam is further detected by the start point detection sensor 458. The laser diode (for example, the laser diode 438a) used as a reference when correcting the color misregistration of
₃ Turn on (for example, 50 μsec) and turn off. The turning off of the laser diode during the period corresponding to the predetermined time t ₂ may be omitted and the turning on of the laser diode may be continued during the period corresponding to t ₁ + t ₂ + t ₃ . As described above, the turning-on / off of the laser diode is periodically performed in synchronism with the detection cycle of the laser beam by the start point detection sensor 458, and during this detection cycle, that is, the laser beam is controlled once. The image is exposed on the photosensitive material 16 each time the scanning is performed.

That is, the image data for recording from the look-up table 244 is converted into pulse width modulation circuits 250 and 25.
2, 254, and pulse width modulation circuits 250, 25
In 2, 254, pulse signals whose pulse widths are modulated according to the density of each pixel are generated, and laser driving circuits 256, 258,
Output to 260. The pulse modulation circuits 250 and 25
In Nos. 2 and 254, modulation is performed using pixel clock signals having different phases selected in the color misregistration correction described above. In the laser drive circuit 256, the drive current is modulated by the pulse signal input from the pulse width modulation circuit 250 and supplied to the semiconductor laser 442a. Similarly, for the laser drive circuits 258 and 260, the drive current is modulated by the pulse signal input from the pulse width modulation circuits 252 and 254 and supplied to the semiconductor lasers 442b and 442c.

As a result, the semiconductor lasers 442a and 442a
Laser beams L1, L2, and L3 having a predetermined light output are emitted from the laser diodes 2b and 442c, respectively.
Laser beams L1 and L emitted from each semiconductor laser
2 and L3 are reflected by the reflection mirror 446 and then scanned in the main scanning direction by the polygon mirror 448, and the fθ lens 45
The light passes through 0, is sequentially reflected by the cylindrical mirrors 452, 454, and is irradiated onto the photosensitive material 16. At this time, the photosensitive material 16 is conveyed to perform sub-scanning,
As a result, the image is exposed on the photosensitive material 16.

The target value A ₁ <target value A ₂ is that the optical output from the laser diode is higher than the rated value due to the temperature fluctuation of the semiconductor laser when the laser diode is switched from the continuously lit state to the modulated state. This is to prevent the laser diode from being deteriorated due to the laser beam being emitted in. When the lighting of the laser diode is switched to the modulated lighting, the duty ratio of the laser diode is reduced, and the light emission efficiency is improved. In the above-mentioned modulation, the dynamic range of the exposure amount is set to the dynamic range required for the initial sensitivity of the photosensitive material 16, the variation of the photosensitive characteristics of the photosensitive material 16 for each lot, and the photosensitive characteristics of the photosensitive material 16 over time. The variation is determined in consideration of the machine difference of the hardware including the semiconductor laser 442, and the modulation is performed so that the dynamic range of the actual exposure amount corresponds to the determined dynamic range.

Further, in the exposure of each pixel, in order to avoid the overshoot of light when the laser diode which has been stopped is made to emit light, the laser drive circuits 256 and 25 are used.
8, 260 modulation circuits and laser diode 438
a, 438b, 438c, and capacitors and resistors are inserted between the laser diodes 438a, 438b, 43.
It is preferable to slow down the rise of the drive current flowing through 8c. It is suitable that the time constant of the capacitor and the resistance is 1/8 or more, preferably 1/4 or more of the pixel period. In addition, laser diodes 438a, 438b,
Since 438c is a laser diode of a different type that emits a laser beam having a different wavelength, the characteristics thereof are also different. Therefore, the time constant may be changed according to the characteristics that are different for each type. Further, even if the laser diodes are of the same type, there are variations in characteristics among individuals. Therefore, the characteristics may be measured for each individual, and an optimal time constant may be set according to each individual.

Further, it is preferable to supply a constant bias current to the laser diode even when the light emission of the laser diode is stopped during the image exposure. This is because when the drive current is suddenly supplied from the state where the bias current is not supplied, the emission delay time of the laser diode may reach several tens of nanoseconds. However, when the bias current is large, the photosensitive material may be slightly exposed (exposed) by the laser beam of a minute power emitted from the laser diode. Therefore, the magnitude of the bias current is set to several mA (for example, 5 m) so that the exposure amount of the photosensitive material by the laser beam of the minute power becomes about 1/1000 of the exposure amount for obtaining the maximum density.
It is preferable that the value is about A). This bias current may be always supplied while the power of the image recording apparatus 10 is turned on, or may be supplied in synchronization with the rotation of the polygon mirror. Only during exposure (667 μsec as an example),
You may make it flow.

By the way, in this embodiment, the photosensitive material 16 having sensitivity to light in the infrared region is used as the photosensitive material, and the photosensitive characteristics such as sensitivity and color balance of the photosensitive material 16 are changed by the influence of temperature and the like. The image quality also changes according to the change in the photosensitive characteristics of the photosensitive material 16 when the image is exposed. Therefore, the control unit 248 performs exposure based on the temperature around the exposure unit 22 detected by the temperature sensors 32 and 34 and the temperature around the conveyance path of the photosensitive material 16 that reaches the exposure unit 22 and the table stored in the ROM 264. A value of drive current control data output to the laser drive circuits 256, 258, 260 based on a correction value for correcting the variation of the photosensitive characteristic of the photosensitive material 16 that has reached the portion 22 from the standard value. Have changed.

As a result, for example, when the surface temperature of the photosensitive material 16 rises and the sensitivity rises, the temperature sensor 3
The increase of the surface temperature is detected based on the detected values of 2 and 34, and the value of the drive current control data is changed so that the increase of the sensitivity is corrected, that is, the optical output of the laser beam is reduced. become. Further, when the color balance changes due to temperature, the value of the drive current control data is changed with a different change amount for each laser drive circuit 256, 258, 260 according to the change in color balance. As a result, even if the photosensitive characteristics of the photosensitive material 16 at the time of reaching the exposure unit 22 change due to fluctuations in temperature and humidity around the exposure unit 22 and in the vicinity of the transport path leading to the exposure unit 22, the magnitude of the drive current is changed. Is controlled and the exposure amount is controlled to be corrected.
The quality of the image exposed to the image No. 6 and the image transferred to the image receiving material 108 is prevented from changing.

The control of the exposure amount for correcting the photosensitive characteristics of the photosensitive material 16 is not limited to changing the drive current of the laser diode as described above.
For example, the value of the image data sequentially output from the look-up table 244 may be changed as a whole, and the D / A conversion may be performed by changing the level of the reference voltage supplied to the D / A converter 216. The conversion characteristic in the device 216 may be changed. Further, an optical element whose transmittance or reflectance is controllable, for example, an electrochromic element whose transmittance changes according to an applied voltage, a liquid crystal shutter, an ND filter or the like is provided on the optical path of the laser beam emitted from the laser diode. It can also be done by changing the transmissivity or reflectivity of the element.

In the present embodiment, the case where the image is exposed by using the pulse width modulated laser beam has been described as an example, but the power of the laser beam when exposing each pixel is changed according to the density of each pixel. In the case of exposing an image using a so-called power-modulated laser beam, the exposure is performed by changing the power of the laser beam as a whole or by changing the exposure time of each pixel of the laser beam as a whole. The amount can be controlled.

Further, the part for detecting the temperature is not limited to the above, and another part that affects the temperature of the photosensitive material when reaching the exposure position, for example, the temperature of the magazine or the like is detected, The exposure amount may be corrected based on the detected temperatures of the plurality of parts. Also,
Since the photosensitivity of the photosensitive material also changes depending on the humidity, a humidity sensor that detects the humidity around the exposure position, etc.
The exposure amount may be corrected according to the detected temperature and humidity, or only the humidity sensor may be provided and the exposure amount may be corrected according to the detected humidity.

By the way, in the semiconductor laser, the relationship between the current and the light quantity greatly changes depending on the temperature, and the wavelength of the laser output from the semiconductor laser also changes. In order to suppress these fluctuations, it is common practice to keep the semiconductor laser at a constant temperature. Although it is possible to heat or cool the Peltier element, there is a disadvantage in that the cost is high. Therefore, in this embodiment, the semiconductor lasers 442a, 442b and 442c are press-fitted into the heat sink made of aluminum, and the thermistor and the power transistor are fixed to this heat sink.

In the control unit 248, as the target temperature of the heat sink, a value equal to or higher than the maximum value of the above-mentioned environmental temperature (for example, a value of 40 ° C. or higher when the environmental temperature inside the image recording apparatus rises up to 40 ° C.) Is set, and the energization of the power transistor (the energization time width or the magnitude of the energized current) is controlled via the drive circuit so that the temperature detected by the thermistor becomes the target temperature. As a result, the heat sink can be maintained at a substantially constant temperature regardless of changes in the environment inside the image recording apparatus.

However, since the thermal resistance exists between the semiconductor laser and the heat sink, the temperature of the semiconductor laser changes depending on the light emission history of the semiconductor laser. In order to avoid the influence of this temperature fluctuation, as described above, the APC control unit 2
APC control by 46 is performed. As described above, the APC control is not limited to capturing the optical output data every time the laser beam is main-scanned and monitoring whether or not the optical output is maintained at a predetermined level.

For example, when the time from the end of the exposure in one main scan to the start of the exposure in the next main scan is long (for example, several hundreds of microseconds or more), it is possible to deal with each time. It is not necessary to perform APC control every time the exposure to be performed is completed. This is because the thermal time constant of the semiconductor laser is about several hundred microseconds, and the image history does not affect the next raster. In this case, the light output data is fetched by a predetermined value between the end of the exposure of one image and the start of the exposure of the next image, or every time the laser beam is main-scanned a plurality of times. It may be possible to monitor whether or not it is held in the.

On the other hand, the inventor of the present invention develops C (cyan) or Y (yellow) with light in the infrared region and M (magenta) with red light, like the light-sensitive material 16 used in this embodiment. Various experiments were conducted on the heat-developable color light-sensitive material to clarify the following.

Beam Diameter Dependence The beam diameter was changed by changing the position of the optical element of the optical system through which the laser beam emitted from the semiconductor laser passes, and the change in the coloring density of the heat-developable color photosensitive material was investigated. However, in the main scanning direction, no observable density fluctuation was observed with respect to the beam diameter fluctuation. On the other hand, in the sub-scanning direction, density fluctuations were observed with respect to beam diameter fluctuations, and it was found that the density decreased as the beam diameter increased.

Environmental Temperature Dependence When the environmental temperature of the image recording apparatus is changed with the beam diameter kept constant, as described in the section “Means for solving the problem”, the fluctuation of the image density is observed and the environmental temperature is changed. It has been found that the image density increases with increasing.

From the above-mentioned beam diameter dependency, it is understood that if the beam diameter varies in the sub-scanning direction, so-called shading may be observed in the recorded image, which is density unevenness with a low spatial frequency. it can. In order to solve this problem, the following method can be considered. That is, in order to reduce the variation in the beam diameter in the sub-scanning direction that causes the density variation, the variation in the beam diameter in the sub-scanning direction is reduced by prioritizing the variation in the beam diameter in the main scanning direction. The position of each optical element that constitutes the optical system is adjusted.

Specifically, the allowable range of the beam diameter variation along the sub-scanning direction is set to about 1/2 of the beam diameter variation along the main scanning direction, and the beam diameter variation along the sub-scanning direction is set. The tilts of the fθ lens, the cylindrical mirror, the mirror, the polygon mirror, etc. are adjusted so that As a result, it is possible to suppress the variation of the beam diameter along the sub-scanning direction within ± 10% and reduce shading.

Further, it is known that when the environmental temperature of the image recording apparatus changes, the beam diameter also changes in addition to the image density variation due to the environmental temperature dependency (see FIG. 10 as an example). A change in the image density due to the change in the beam diameter also occurs. To solve this,
The following methods are possible.

As the ambient temperature rises, the beam diameter of the laser beam along the main scanning direction and the sub-scanning direction changes due to the air flow of the apparatus and the twisting of the optical frame due to the heat conduction of the frame metal. For example, when the generatrix (see FIG. 11) of the concave or convex cylindrical lens arranged on the optical path of the laser beam is twisted due to the change in environmental temperature, the beam diameter changes in both the main scanning direction and the sub scanning direction.
Therefore, if each optical element of the optical system is arranged at a suitable position at a low temperature when the optical system is adjusted and the busbar is twisted to increase the beam diameter when the environmental temperature rises, the beam diameter dependence and The environmental temperature dependency is offset by each other, and the amount of concentration fluctuation can be reduced.

When a laser beam is pulse-width modulated in accordance with an image by a pixel clock having a constant frequency as in this embodiment and an image is formed on a photosensitive surface of a photosensitive material by an fθ lens, an image is formed in principle. Each dot can be exposed at a constant interval, but when the distortion of the fθ lens is large (fθ property is poor), the interval of each dot changes and the photosensitive material is irradiated when recording each dot. The light intensity of the generated laser beam may vary.

In such a case, with respect to the change of the dot interval, each dot of the image data is interpolated by interpolation so that the image data becomes equal to the data obtained by sampling the image at the timing corresponding to the changed dot interval. The value of may be modified. Further, the fluctuation of the light intensity of the laser beam may be electrically controlled by changing the magnitude of the driving current, or may be corrected by modifying the modulation characteristic. Further, in the optical element that is arranged on the optical path of the laser beam and transmits or reflects the laser beam, a distribution of transmittance or reflectance that cancels the fluctuation of the intensity is formed, and the intensity of the laser beam is apparently constant. May be

In the above embodiment, a pulse width modulation circuit is provided for each semiconductor laser (pulse width modulation circuits 250, 2
52, 254), one APC control unit is provided in common for each semiconductor laser (APC control unit 246), but the present invention is not limited to this, and an APC control unit is provided for each semiconductor laser to perform APC control. The optical output of the semiconductor laser (laser diode) may be independently controlled in each of the sections. Alternatively, one pulse width modulation circuit and one APC control unit may be provided in common for each semiconductor laser, and the pulse width modulation circuit and APC control unit may sequentially perform processing on each semiconductor laser. However, in this case, it is preferable to record an image with three times the scanning line density by, for example, reducing the conveying speed of the photosensitive material to 1/3.

The characteristics of a circuit for generating a pixel clock (hereinafter, this circuit is referred to as a clock generator), which is a part of the main controller 242, is changed by the influence of the ambient temperature and the like, and the pixel clock wave is changed. When the high value (amplitude) or the duty ratio fluctuates, the modulation characteristic of the pulse width modulation circuit fluctuates, which adversely affects the density and color balance of the image. In such a case, it is preferable to control the temperature of the clock generator to be a constant temperature. Specifically, it is preferable to use a thermistor and a power transistor as in the case of the semiconductor laser described above. Also, the clock generator is an IC
In this case, a heat sink having a thermistor and a power transistor attached thereto may be brought into contact with the IC. In this case, the thermistor is preferably embedded in the heat sink.

Further, the main controller 242, the pulse width modulation circuits 250, 252, 254, the laser drive circuit 25.
The control device 220 including 6, 258 and 260 is preferably arranged at a position close to the semiconductor lasers 442a, 442b and 442c of the exposure device 90. This is because the stray capacitance of the cord electrically connecting each circuit and the semiconductor laser causes a time delay in the rise and fall of the signal flowing in each cord. For the same reason, it is preferable that the cord is electrostatically shielded. Although each circuit that constitutes the control device 220 may be mounted on the same substrate or may be mounted on different substrates, considering the influence of the above-mentioned stray capacitance, all the circuits are mounted on the same substrate. The pulse width modulation circuits 250, 252, 254 are mounted on the same substrate and the laser driving circuits 256, 258, 2 are mounted on different substrates.
It is preferable to reduce the number of substrates as much as possible such as mounting 60.

Further, in the above embodiment, the image recording apparatus which drives the semiconductor laser by pulse width modulation to expose the image has been described as an example, but the invention is not limited to this, and power (optical output) modulation or It is also possible to apply to a device that drives a semiconductor laser by pulse number modulation to expose an image. Further, the exposure repetition period in the above embodiment, that is, the period of the pixel clock (modulation period) is not limited to a specific numerical value, and may be appropriately determined according to the rotation speed of the polygon mirror and the recording density of the pixels. Although possible, as an example, when recording a high-quality image in which gradation is important, the cycle is several tens of nanoseconds to several tens of seconds.
0nsec (For example, using a 6-sided polygon mirror, the rotation speed of the polygon mirror is 7500 rpm, and the pixel recording density is 400
Pixels / inch (dpi) is preferably about 200 nsec), but it can be increased to several μsec (for example, polygon mirror rotation speed is 2500 rpm and pixel recording density is 200 dpi, about 1.2 μsec). It is possible.

Furthermore, the present invention is not limited to the image recording apparatus for recording the finished image on the image receiving material by transferring the image exposed on the photosensitive material to the image receiving material as described in the above embodiments. It can also be applied to an image recording apparatus for recording a finished image on a photosensitive material by developing the photosensitive material.

[0090]

As described above, the present invention detects at least one of temperature and humidity around at least one of the periphery of the exposure position and the periphery of the conveyance path of the photosensitive material reaching the exposure position, and at least one of the detected temperature and humidity. Based on the above, the exposure amount of the photosensitive material in the exposure unit is controlled so that the change in the photosensitive characteristic of the photosensitive material is corrected, so that the image quality can be changed regardless of the change of the photosensitive characteristic of the photosensitive material. The excellent effect that it can be prevented is obtained.

[Brief description of drawings]

FIG. 1 is an external view of an image recording apparatus.

FIG. 2 is a schematic overall configuration diagram of an image recording apparatus according to the present embodiment.

FIG. 3 is a schematic configuration diagram showing an enlarged view of a conveyance path from a photosensitive material magazine to an exposure unit and a periphery of the exposure unit.

FIG. 4 is an exploded perspective view showing a wind direction changing plate and a fan box according to this embodiment.

FIG. 5 is a plan view showing a flow of outside air which is made to flow to the exposure unit by the wind direction changing plate according to the present embodiment.

FIG. 6 is a perspective view showing a schematic configuration of an exposure apparatus.

FIG. 7 is an exploded perspective view for explaining the appearance and attachment of the exposure apparatus.

FIG. 8 is a block diagram showing a schematic configuration of a control device.

FIG. 9 is a timing chart showing the light output of the laser diode when the image is exposed in the exposure mode, the timing at which the data detected by the light output is captured, and the output of the starting point detection sensor.

FIG. 10 is a diagram showing a change in beam diameter with respect to a change in temperature.

FIG. 11 is a perspective view showing twist of a generatrix of a cylindrical lens.

[Explanation of symbols]

 10 Image Recording Device 16 Photosensitive Material 32 Temperature Sensor 34 Temperature Sensor 248 Control Section 442 Semiconductor Laser

Claims (1)

[Claims] 1. A transporting means for transporting a photosensitive material, which has at least one infrared-sensitive layer sensitive to light in the infrared region and whose photosensitive characteristic is changed by a change in at least one of temperature and humidity, to an exposure position, and red. A light beam emitting means for emitting a light beam in the outer region; an exposure unit for scanning and exposing an image on the photosensitive material conveyed to the exposure position by the light beam emitted from the light beam emitting means; Detecting means for detecting at least one of temperature and humidity in at least one of the periphery of the conveying path of the photosensitive material reaching the position, and a change in photosensitive characteristics of the photosensitive material based on at least one of temperature and humidity detected by the detecting means. And an exposure amount control unit that controls the exposure amount of the photosensitive material in the exposure unit so that