JPH10193676A - Apparatus for forming image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form high-quality images with good processing efficiency without deteriorating finish quality even at the occurrence of errors in the movement amount of a sub scan. SOLUTION: A dot 452 is formed by a main scan and exposure of the (n)th time at an overlapping area 450 formed by a sub scan of a predetermined amount, thereby partly forming a main scan line of the overlapping area 450. A dot 454 is formed at a part without the dot 452 by the main scan and exposure of the (n+1)th time. The main scan line is completed in this manner. Since a boundary part between the dots 452 and 454 is not even in a sub scan direction P, a streak-shaped irregularity extending in a main scan direction W is not given rise to even at the occurrence of an error in the movement amount of the sub scan.

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 an image forming apparatus that exposes a photosensitive material based on digital image data and forms an image corresponding to the digital image data.

[0002]

2. Description of the Related Art At present, an image forming apparatus modulates a spot-like light beam (hereinafter, referred to as "spot light") emitted from a semiconductor laser, a light emitting diode (LED) or the like based on digital image data. In some cases, an image is formed on a recording medium by performing main scanning and sub-scanning. Also,
In this image forming apparatus, the density of the dots to be formed is changed by changing the intensity of the spot light in accordance with the digital image data at the time of scanning exposure, so that the density of the dot corresponding to the digital image data is changed on the recording medium. There are some which form dots.

An image forming apparatus using LEDs as light emitting elements has been proposed in which a plurality of LEDs are arranged in a sub-scanning direction, and a main material is simultaneously scanned by the plurality of LEDs to expose a photosensitive material. . In this image forming apparatus, LEDs that form lines of dots that are individually continuous along the main scanning direction (hereinafter, referred to as “main scanning lines”) are arranged along the sub-scanning direction and perform main scanning at the same time. Thus, exposure with a predetermined exposure width along the sub-scanning direction of the photosensitive material can be performed in one main scan. Therefore, even when a high-quality image in which the intervals between the main scanning lines are tight is formed, the number of times of main scanning does not increase, and efficient image formation can be performed in a short time.

[0004]

However, when performing exposure with a predetermined exposure width, sub-scanning is performed so that the amount of movement is in accordance with the exposure width. At this time, if the amount of movement by the sub-scanning is not accurately controlled, the interval between the main scanning lines is partially changed, resulting in streak-like density unevenness along the main scanning direction. In particular, repetition of exposure with a relatively wide exposure width causes streak-like density unevenness to appear at regular intervals, which causes a problem that the finished quality of an image formed with high image quality is impaired.

The present invention has been made in view of the above-mentioned facts, and has as its object to provide an image forming apparatus capable of forming an image having a high finish quality with a high processing efficiency.

[0006]

According to a first aspect of the present invention, an exposure light source and a photosensitive material are relatively moved in a main scanning direction and a sub-scanning direction, and a light beam from the exposure light source is converted into digital image data. An image forming apparatus that scans and exposes a photosensitive material based on an image to form an image, wherein the exposure light source includes:
A plurality of light emitting elements are arranged so as to emit a plurality of light beams along the sub-scanning direction, and a main scanning exposure for simultaneously forming a plurality of main scanning lines by a main scanning is performed. A sub-scanning amount adjusting unit that adjusts a sub-scanning amount so that a plurality of main scanning lines overlap at the next main scanning exposure, and an exposure dot according to the digital image data in the overlapping main scanning line area, Light emitting control means for selectively setting exposure dots to be formed in the preceding main scan and exposure dots to be formed in the subsequent main scan, and controlling light emission so as to perform exposure according to the digital image data. It is characterized by.

According to the present invention, by performing sub-scanning with the sub-scanning amount set by the sub-scanning amount setting means, a plurality of main scanning lines are overlapped during two consecutive exposures, and an overlapping main scanning line area is provided. A large number of continuous exposure dots constituting all the main scanning lines are formed by two main scanning exposures. Which exposure dots are formed in the first main scan and the second main scan may be set in advance,
Also, it may be set each time. In addition, the main scanning exposure is an exposure process that is continuously performed at predetermined time intervals while performing main scanning. For this reason, an exposure pattern in which exposure dots are formed by the current main scanning exposure is determined. Main scanning exposure is performed by turning on light emitting elements corresponding to overlapping main scanning line regions based on the exposure pattern.

As a result, in the overlapped main scanning line area, a total of two main scanning exposures of the current main scanning and the next or previous main scanning are performed for each main scanning line in accordance with the exposure pattern. All the exposed dots are formed, and each main scanning line is completed.

For this reason, when the sub-scanning is performed, an error in the amount of movement occurs, and the formation positions of the exposure dots constituting each main scanning line in the overlapping main scanning line area are shifted, and the exposure dots approach or separate from each other. Even if unevenness occurs in the interval between the exposure dots, the unevenness is arranged along the exposure pattern and does not extend linearly in the main scanning direction. As a result, even if density unevenness occurs due to the unevenness, the density unevenness does not extend linearly in the main scanning direction. This makes it possible to prevent the occurrence of streak-like unevenness extending in the main scanning direction even if an error in the movement amount occurs.

Accordingly, the quality of the finished image is not impaired by the stripe-shaped unevenness, and a high-quality (high-resolution) image can be efficiently formed.

The exposure dots set by the setting means can be set irregularly within the overlapping main scanning line area. For example, in an overlapping main scanning line region constituted by a plurality of main scanning lines, in a stepping stone shape, that is, in an overlapping main scanning line region,
The exposure dots selected for one main scan can be set as exposure dots that are not formed simultaneously with any of the adjacent exposure dots. When the exposure dots formed in one main scan are continuous along the main scan direction, it is preferable that the number of continuous dots is not large. This is because, as the number of continuous pixels increases, the stripe-shaped density unevenness extending in the main scanning direction becomes more conspicuous.

According to a second aspect of the present invention, the exposure dots formed in the preceding main scanning and the exposure dots formed in the subsequent main scanning are each formed continuously in the sub-scanning direction. Features.

According to the present invention, when a plurality of main scanning lines are formed in an overlapping main scanning line area, exposure dots are formed continuously in the sub-scanning direction in each main scanning. Note that the continuously formed exposure dots include continuous exposure dots in the overlapping main scanning line region and continuous exposure dots in the non-overlapping region. This makes it possible to form exposure dots by varying the number of exposure dots in the sub-scanning direction in the overlapping main scanning line area along the main scanning direction. The variation in the number of the exposure dots in the sub-scanning direction becomes a notch in the sub-scanning direction according to the exposure pattern, resulting in a large unevenness. For this reason, even if an error in the amount of movement occurs in the sub-scanning, unevenness in the interval between the exposure dots occurs in a large uneven shape, so that the occurrence of streak-like unevenness extending in the main scanning direction can be further prevented. .

According to a third aspect of the present invention, the exposure light source and the photosensitive material are relatively moved in the main scanning direction and the sub-scanning direction.
An image forming apparatus that scans and exposes a light beam from the exposure light source onto a photosensitive material based on digital image data to form an image, wherein the exposure light source emits a plurality of light beams along a sub-scanning direction. A plurality of light emitting elements are arranged as described above, and main scanning exposure for simultaneously forming a plurality of main scanning lines by main scanning is performed, and after one main scanning exposure,
A sub-scanning amount adjusting unit that adjusts a sub-scanning amount so that a plurality of main scanning lines overlap at the time of the next main scanning exposure, and an exposure dot corresponding to the digital image data in the overlapping main scanning line area. Light-emission control means for selectively setting exposure dots formed in an overlapped manner in main scanning and subsequent main scanning, and controlling light emission so that an exposure amount according to the digital image data is obtained by overlapping exposure. It is characterized by.

According to the present invention, by performing sub-scanning with the sub-scanning amount set by the sub-scanning amount setting means, a plurality of main scanning lines are overlapped during two consecutive exposures, and an overlapping main scanning line area is provided. The exposure dots to be repeatedly exposed by two main scanning exposures are selected from a large number of continuous exposure dots constituting all the main scanning lines. The exposure amount of the selected exposure dot becomes an exposure amount according to the digital image data by two main scanning exposures. Therefore, an exposure pattern in which the exposure amount in each main scanning exposure is set for the selected exposure dot is determined. According to this exposure pattern, the exposure dots selected to be overlap-exposed are
It is determined which of the two main scans is formed by exposure mainly.

As a result, even if there is an error in the amount of movement during sub-scanning, each exposure dot of the corresponding amount of exposure formed by each of the two exposures forming one exposure dot by overlapping exposure is exposed. Since the exposure dots are formed so as to be displaced along the pattern and the exposure dots are continuous due to the displaced exposure dots, unevenness in the interval between these exposure dots is not linearly arranged. For this reason, the density in the main scanning direction becomes irregular, and the occurrence of density unevenness extending in the main scanning direction can be prevented.

The same exposure amount in one main scan, that is, 50% of the exposure amount according to digital image data
Each main scanning exposure can be performed with a light amount. When the exposure dots of such an exposure amount are continuous in the main scanning direction, it is preferable that the number of continuous dots is small. When the number of continuous colors is small, it is possible to prevent density unevenness extending in the main scanning direction.

When a plurality of main scanning lines are arranged in the overlapping main scanning line area, overlapping exposure may be selected for all the exposure dots of the main scanning lines. You may select for dots. When all the main scanning lines are selected, all the main scanning lines in the overlapping main scanning line area are formed by the overlapping exposure. On the other hand, when the exposure dots of some of the main scanning lines are selected, the exposure dots may be formed for the non-selected main scanning lines.

Further, the exposure pattern can be changed for each main scan. As a result, the set exposure dot is changed for each main scan, so that even if an error occurs in the amount of movement in the sub-scanning direction, the resulting unevenness is repeated at a constant cycle in the sub-scanning direction. In addition, the streak-like unevenness extending in the main scanning direction can be made less noticeable.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION

(Overall Configuration “Appearance”) FIGS. 1 to 3 show an image forming apparatus 100 according to the present embodiment.

The image forming apparatus 100 includes an optical disc 1
This device reads image data recorded on the FD 02 or the FD 104 (see FIG. 3), exposes the photosensitive material 106, and transfers an image recorded on the photosensitive material 106 to an image receiving paper 108 for output.

The upper portion of the front surface (left side in FIG. 3) of the box-shaped casing 110 has an inclined surface, and an operation display unit 112 is provided.

As shown in FIG. 2, the operation display unit 112
Are classified into a monitor unit 114 located on the right side and an input unit 116 located on the left side, and the monitor unit 114 is configured to project the read image.

The input unit 116 is provided with a plurality of operation keys 1.
18 and an input data confirmation display unit 120, so that it is possible to input data necessary for image formation, such as input of the number of recording sheets, size setting, color balance adjustment, negative / positive selection, and the like. I have. The operation keys 118 include a pattern execution key 117 described later.

Below the operation display section 112, a deck section 1 is provided.
22 are provided. The deck section 122 includes an optical disk deck section 124 located on the right side in FIG. 3 and an FD deck section 126 located on the left side.

The optical disk deck 124 can open and close the tray 130 by pressing an open / close button 128. By mounting the optical disk 102 on the tray 130, the optical disk 102
Can be loaded inside the device.

On the other hand, the FD deck section 126 is provided with an FD insertion throttle 132, and when the FD 104 is inserted, the drive system inside the apparatus operates to draw in the FD 104. When the FD 104 is taken out, the operation button 134 is pressed to
D104 can be pulled out.

The optical disk deck 124 and the FD
Access lamps 136,
138 are provided, and the access lamps 136 and 138 are turned on during access in the apparatus.

A discharge tray 140 is provided further below the deck 122. This discharge tray 140
Is usually housed in the device, and can be pulled out by putting a finger on the grip portion 142 (FIG. 1).
reference).

The image receiving paper 108 on which the image is recorded is discharged onto the discharge tray 140.

The receiving paper 108 is stored in a tray 144 in advance in a layered manner.
0 is provided in the tray loading port 146 provided on the upper surface of the tray. The image receiving paper 108 is taken out one by one from the tray 144 loaded in the tray loading port 146, the image is transferred, and then guided to the discharge tray 140.

Two circular cover members 148 and 150 are mounted on the right side surface (the front side in FIG. 1) of the casing 110. The cover members 148, 150
The cover members 148 and 148 are individually detachable.
As shown in FIG. 3, a supply reel 152 and a take-up reel 154 for winding the photosensitive material 106 in a roll form are arranged inside the apparatus along the axial direction of 150. It can be taken out or loaded with the members 148 and 150 detached. (Receiver paper transport system) As shown in FIG.
The upper surface of the tip end of the tray 144 loaded in 46 is opposed to the half-moon roller 156.

The semicircular roller 156 has a part of its peripheral surface cut in a tangential direction. Usually, the notch 158 faces the uppermost image receiving paper 108 in the tray 144 at a predetermined interval. I have. Here, when the half moon roller 156 rotates, the uppermost image receiving paper 108 and the half moon roller 156 are rotated.
When the semicircular roller 156 makes one rotation, the image receiving paper 108 is slightly pulled out. The pulled-out image receiving paper 108 is nipped by the first roller pair 160,
The driving force of the first roller pair 160 causes the tray 1
44 to be completely drawn out.

On the downstream side of the first roller pair 160,
Roller pair 162, guide plate 164, third roller pair 1
66 are arranged in order, and the image receiving paper 108 is nipped by the first roller pair 160, is nipped by the second roller pair 162, is guided by the guide plate 164, and is received by the third roller pair 166. Be pinched.

The third roller pair 166 also overlaps with the photosensitive material 106. That is, the third roller pair 166 is also used as a transport path for the photosensitive material 106. (Photosensitive material transport system) The photosensitive material 106 is supplied to the supply reel 15.
It is loaded into the device in the form of a long roll wound in two layers. The supply reel 152 is formed by removing the cover member 150 (rear side of the apparatus) and inserting the cover member 150 in the axial direction.
It can be loaded in place.

With the photosensitive material 106 loaded at a predetermined position, the outermost layer is pulled out and loaded along a predetermined transport path as an initial setting. In the loading procedure, the outermost layer is pulled out from the supply reel 152, and the fourth roller pair 1 near the loading position of the supply reel 152
68, via the reservoir 170 and the guide plate 172, between the third roller pair 166, around the heat roller 174, and around the take-up reel 154. In this case, a leader tape of a length necessary for loading may be provided at the leading end of the photosensitive material 106 wound around the supply reel 152.

In the conveying path of the photosensitive material 106,
An exposure section 176 is provided between the fourth roller pair 168 and the reservoir section 170. In addition, the reservoir 170
A water application unit 178 is provided between the guide plate 172 and the guide plate 172. The details of the exposure unit 176 and the water application unit 178 will be described later. However, after the image is exposed on the photosensitive material 106 by the exposure unit 176, the third step is performed in a state where water is applied to the emulsion surface (exposed surface). Receiving paper 1 with roller pair 166 of
08 is superimposed. (Heat Roller) The heat roller 174 is a thermal development transfer section of the present apparatus, and includes a cylindrical roller main body 180 and a heater 182 provided along an axis inside the roller main body 180. The surface of the roller body 180 is heated by the operation of the heater 182, and has a role of applying heat to the members (the photosensitive material 106 and the image receiving paper 108) wound around the roller body 180. By this heating, a thermal development transfer process is performed, and the image recorded on the photosensitive material 106 is transferred to the image receiving paper 108.

A peeling roller 184 and a peeling claw 186 are provided near the lower right of the heat roller 174, and the image receiving paper 108 wound around the heat roller 174 by about 1/3 is peeled off from the photosensitive material 106 to form a discharge tray. The image receiving paper 108 is guided in a 140 direction.

On the other hand, the photosensitive material 106 is
The take-up reel 154 is wound by about 、, is turned by 180 °, and is guided to a position where the take-up reel 154 is loaded. (Water application unit) As shown in FIG.
Water as an image forming solvent is applied to the photosensitive material 106 or the image receiving paper 108, and the superposed surfaces of the two are brought into close contact with each other, and have a role of heat development. Application piece 188 and tank 190 for storing water
It is composed of

The coating piece 188 is made of a highly absorbent material such as felt or sponge and has an appropriate hardness.
The photosensitive material 106 comes into contact with a predetermined pressure during transportation. The water in the tank 190 always transfers an appropriate amount to the coating piece 188 by utilizing the capillary phenomenon. When the photosensitive material 106 and the coating piece 188 come into contact with each other, the water is exposed by the coating piece 188. Water is applied to the surface (emulsion side) of the material 106.

Further, since the coating piece 188 is in contact with the photosensitive material 106 at an appropriate pressure, the water is uniformly applied.

The water in the tank 190 is replenished by removing the entire water application section 178. However, water may always be supplied from outside the apparatus by providing a pipe.

In this embodiment, water is used as the image forming solvent. However, the water is not limited to pure water, but includes water in a widely used sense. Further, it may be a mixed solvent of water and a low boiling point solvent such as methanol, DMF, acetone and diisobutyl ketone. Further, a solution containing an image formation accelerator, an antifoggant, a development terminator, a hydrophilic heat solvent and the like may be used. (Exposure Unit) FIG. 4 shows an exposure unit 176 according to the present embodiment.
It is shown.

The exposure section 176 mainly includes a light source unit 200 provided above the conveying path of the photosensitive material 106.
It is connected to the controller 202. Controller 2
02 stores digital image data (image data read from the optical disk 102 or the FD 104), and turns on the light source unit 204 in the light source unit 200 according to the digital image data.

The light source unit 200 can be moved in the width direction (main scanning direction) of the photosensitive material 106 by driving a main scanning unit 206 corresponding to the scanning means of the present invention described later. Main scanning is performed when the unit 176 is stopped when step driving is performed.

The light source unit 200 of the exposure unit 176 is covered by a box-shaped exposure casing 214, and a light source unit 204 is disposed on the upper end surface of the exposure casing 214. 214
Pointed inward. On the light emitting surface side of the light source unit 204,
An aperture 216 is provided, and a plurality of LED chips 20 are provided.
8 limits the spread of light. Note that the aperture 216 may not be provided.

A telecentric lens 212 is provided on a support portion 215 at the center of the exposure casing 214 downstream of the aperture 216, and collects predetermined light from the light source portion 204 to form an appropriate light on the photosensitive material 106. It has a function of forming an image so as to be focused. The resolution of the light to be imaged is about 250 to 400 dpi.

Here, the telecentric lens 212
Is a lens composed of a plurality of lenses and an aperture, each having a characteristic that the magnification does not change even if the height of the image plane changes. It is possible to absorb the difference due to the state of attachment of the.

The overall focus is constantly adjusted by an unillustrated autofocus mechanism. Alternatively, it is possible to make adjustment unnecessary by using a lens system having a large depth of focus.

The light source unit 204 is composed of a pair of parallel guide shafts 21 forming a part of the main scanning unit 206.
8 supported. The guide shaft 218 is disposed along the width direction of the photosensitive material 106 (the direction of the arrow W in FIG. 4), and the light source unit 204 is connected to the guide shaft 2.
The photosensitive material 106 is movable in the width direction of the photosensitive material 106 by being guided by the photosensitive material 18.

A part of the endless timing belt 220 is fixed to the exposure casing 214 of the light source unit 204. Both ends of the timing belt 220 are wound around sprockets 222 located near both ends of the guide shaft 218, respectively. One sprocket 2
The rotation shaft of the stepping motor 226 is connected to the rotation shaft of the stepping motor 226 via a transmission 224.
It is reciprocated along the guide shaft 218.

As shown in FIG. 6, the stepping motor 226 is connected to the controller 20 via a driver 227.
2 are connected. The drive of the stepping motor 226 is controlled by the controller 202, and the photosensitive material 10
6 is synchronized with the step driving. That is, with the photosensitive material 105 moving one step and stopping, the stepping motor 226 starts rotating, and
4 moves on the photosensitive material 106 along the width direction of the photosensitive material 106. After confirming the predetermined pulse, the stepping motor 226 is rotated in the reverse direction to
Returns to its original position. The next movement of the photosensitive material 106 is started simultaneously with the return operation of the light source unit 204.

As shown in FIG. 4, a photodiode 228 is provided on the light output side of the light source unit 204 and on the surface facing the photosensitive material 106, and outputs a signal corresponding to the light amount of the light source from the light source unit 204. It is supposed to. The photodiode 228 is connected to the light amount correction unit 230, and the signal is input to the light amount correction unit 230.

The light quantity correction unit 230 compares the detected light quantities from the LED chips 208 of the respective colors to determine the density,
It has a role of performing color balance adjustment and outputting a correction value to the controller 202.

As shown in FIG. 5, the light source unit 204 has an L
The ED chips 208 are collectively configured, and the LED chips 208 that emit colors of B (blue), G (green), and R (red), respectively (hereinafter, when individually described for each color, B LED chips that develop colors are BL
ED chip 208B, LED chip emitting G color
LED chip 208G, an R-LED chip 208R is referred to as an R-LED chip 208R).
On the reference numeral 10, the photosensitive material 106 is attached along the width direction (main scanning direction) of the photosensitive material 106 according to the same arrangement rule. Note that each exposure wavelength is 650 ± 20 nm for the R-LED chip 208R and 5 for the G-LED chip 208G.
30 ± 30 nm, 470 for B-LED chip 208B
± 20 nm. That is, at the right end of the substrate 210 in plan view, two rows of ten B-LED chips 208B are provided.
And arranged in a zigzag pattern, 10 R-LEDs on the left end
The chips 208R are arranged in two rows and in a staggered manner, and in the center, ten G-LED chips 208G are arranged in two rows and in a staggered manner. A total of six rows of LED chips are arranged. I have.

A predetermined wiring is formed on the substrate 210 by an etching process or the like. The wiring is covered with metal so as to prevent a short circuit between the wirings, and has a heat radiation function. For this reason, heat generation due to lighting of the LED chip 210 can be suppressed, and fluctuations in the amount of emitted light can be suppressed.

The dimensions of each part of the light source unit 204 applied in this embodiment will be described below. First, the horizontal (X) × vertical (Y) dimensions of the substrate 210 are 5 × 5 mm (maximum),
The outer dimensions (x × y) of the LED chip 208 are about 360 ×
360 μm. The pitch P between rows of the same color is 600 μm
The row pitch L of each column is 520 μm, and the step size D in a staggered form is 260 μm. Gap G between each color
Is determined by the telecentric lens 212 and cannot be unambiguously determined, but it is preferable that the gap dimensions G between R and G and between G and B are the same.

Note that the hatched portion of the LED chip 208 shown in FIG. 5 is a region where light is actually emitted, and as shown by the chain line in FIG. ing.

By the light source section 204 having the above structure, a predetermined number of main scanning lines can be recorded on the photosensitive material 106 by one main scanning for each color. For this reason, the step movement of the photosensitive material 106 is controlled so that driving and stopping are repeated at a pitch twice as large as the width of the main scanning line recorded on the photosensitive material 106. (Reservoir section) The reservoir section 170 is disposed between the exposure section 174 and the water application section 178 as described above, and includes two pairs of nipping rollers 192 and 194 and one dancer roller 196. Have been. The photosensitive material 106 is stretched over two pairs of nipping rollers 192 and 194, and a substantially U-shaped slack is provided in the photosensitive material 106 between them.
The dancer roller 196 moves up and down in response to the slack, and holds the slack portion of the photosensitive material 106.

In the exposure unit 176, the photosensitive material 106 moves stepwise, but in the water application unit 178, it is necessary to convey the photosensitive material 106 at a constant speed for uniform application of water. For this reason,
The photosensitive material 106 is disposed between the exposure unit 176 and the water application unit 178.
The difference in the conveying speeds is caused. To absorb this speed difference,
The dancer roller 196 is moved up and down to adjust the slack amount of the photosensitive material 106 so that the photosensitive material 106 can be simultaneously moved stepwise and at a constant speed.

As shown in FIG. 7, the image forming apparatus 100 overlaps a part of the area that can be exposed by the LED chip 208 of the light source unit 204 on the photosensitive material 106 in the sub-scanning direction P to form an overlapping area. 450 in the overlap region 450 twice (n-th and (n + 1) -th, or
The sub-scanning is repeated to form an image while forming one main scanning line composed of dots 452 and 454 (see FIGS. 8A and 8B) by the (n + 1) th and (n + 2) th main scanning exposures. Can be executed. For this reason, in one main scanning line formed in the overlapping area 450, a formation pattern along the main scanning direction of the dot 452 or the dot 454 selected to be formed by two main scanning exposures, That is, an exposure pattern for forming the dots 452 or 454 is set (see FIG. 8A). With this exposure pattern, one set of LED chips 208 is associated with the main scanning line in the overlapping area 450.

As shown in FIG. 6, the image forming apparatus 10
0 is provided with a pattern execution key 117 for instructing execution of the image forming process as described above. The pattern execution key 117 outputs an execution signal for instructing the start of an image forming process based on a preset exposure pattern by performing a predetermined operation.

The controller 202 includes an exposure control unit 40
0, and the exposure control unit 400
Alternatively, the image signal from the FD 104 is read. The exposure control unit 400 also has an exposure pattern set in advance, is connected to a pattern execution key 117, and inputs an execution signal from the pattern execution key 117 to instruct execution of an image forming process according to the exposure pattern. . Further, a light amount correction unit 230 is connected to the exposure control unit 400, and reads a correction value from the light amount correction unit 230.

The exposure controller 400 includes a controller 20
2 main scanning control unit 410 and sub-scanning control unit 4
12 are connected. The main scanning control unit 410 includes a stepping motor 226 for moving the main scanning unit 206.
Via a driver 227.

The sub-scanning control unit 412 includes a driver 4
The control of the drive of the motor 416 is controlled via the control unit 14. The motor 416 drives the fourth pair of rollers 168 of the photosensitive material transport system and the pair of nipping rollers 19 of the reservoir section by its driving force.
2 (see FIG. 3). Sub-scanning control unit 412
Controls the driving of the fourth roller pair 168 and the sandwiching roller pair 192 to move the photosensitive material 106 step by a predetermined sub-scan amount, and controls the sub-scan in synchronization with the main scan by the main-scan control unit 410 doing.

The sub-scanning control unit 412 includes the exposure control unit 40
From 0, an exposure pattern whose execution is instructed is input. The sub-scanning control unit 412 sets 10 LEDs in advance so that the exposure area of the light source unit 204 overlaps with one main scanning line according to the input exposure pattern.
The sub-scanning amount corresponding to the main scanning by the chip 208 is adjusted, and the sub-scanning amount corresponding to the overlapping area 450 is determined.

The exposure control unit 400 is connected to an LED light amount adjustment unit 404, to which an exposure pattern instructed to be executed is input from the exposure control unit 400. The LED light amount adjustment unit 404 is
LED associated with the main scanning line in the overlapping area 450
The chip 208 is turned on or off according to the input exposure pattern. Here, one set of the associated LED chips 208 is set so that when one is on, the other is always off (see FIG. 8).

The LED light quantity control section 404 is connected to the LED light emission control section 408. LED light emission control unit 40
In step 8, the light emission of all the LED chips 208 provided in the light source unit 204, including the LED chips 208 that are turned on at a predetermined timing during the main scanning according to the exposure pattern, is controlled according to the digital image data.

Therefore, in the image forming apparatus 100, in accordance with the operation of the pattern execution key 117, a part of the exposure area is overlapped by a predetermined sub-scanning amount according to the exposure pattern, and at a predetermined timing in the main scanning direction. The LED chip 208 is turned on, exposure processing is performed in the main scanning direction, and this is repeated in the sub-scanning direction to form an image.

The operation of the present embodiment will be described below. First, the overall flow for image formation will be described.

The tray 144 is loaded in the tray loading port 146, and the supply reel 152 with the photosensitive material 106 wound thereon and the empty take-up reel 154 are loaded at predetermined positions, respectively, and the loading is completed. When the print start key of the operation display unit 112 is operated, the controller 202 causes the optical disk 102 or the FD 104 to operate.
And reads and stores the image data.

When the controller 202 stores the image data, the supply reel 152 is driven, and the conveyance of the photosensitive material 106 is started.

When the photosensitive material 106 reaches a predetermined position of the exposure unit 176, the photosensitive material 106 stops temporarily, and an image signal is output from the controller 202 to the light source unit 204. This image signal is output every 10 lines,
4 performs exposure at predetermined close intervals while moving along the width direction of the photosensitive material 106 while being guided along the guide shaft 218 by the driving of the stepping motor 226 to form a main scanning line composed of a large number of dots 280. I do.

At this time, before the output of the digital image signal is started, the light amount of each color from the light source unit 204 is detected by the photodiode 228, and the light amount correction unit 2
At 30, a correction value for adjusting the density, the color balance, and the like is supplied to the controller 202 to correct the image signal. This correction value is executed for each image.

When one main scanning exposure is completed, the photosensitive material 106 moves one step at a predetermined pitch and stops.
The second main scanning exposure is performed. By repeating this, an image for one frame is recorded on the photosensitive material 106.

The photosensitive material 106 on which recording has been completed is
By driving only the pair of holding rollers 192 on the upstream side of the reservoir 170 (the pair of holding rollers 194 on the downstream side is stopped),
It is held in a slack state in the reservoir section 170 so as to be wound around the dancer roller 196, and does not reach the water application section 178.

When the length of the photosensitive material 106 for one image is accumulated in the reservoir 170, the pair of nipping rollers 194 on the downstream side of the reservoir 170 starts driving. As a result, the photosensitive material (image formed) 106 is transported to the water application unit 178. In the water application section 178, the photosensitive material 106 is conveyed at a constant speed, and water is uniformly applied by the application piece 188.

The coating piece 188 is constantly supplied with water from the tank 190, and is supplied with the photosensitive material 10 at a predetermined pressure.
6 is pressed, an appropriate amount of water is applied to the photosensitive material 106.

The photosensitive material 106 to which the water has been applied is guided by the guide plate 172 and conveyed to the third roller pair 166.

On the other hand, the image receiving paper 108 is
Makes one rotation, the peripheral surface of the half-moon roller 156 and the leading end of the image receiving paper 108 come into contact with each other, and the uppermost layer of the image receiving paper 108
Is pulled out, and the first roller pair 160 is pinched. The driving of the first roller pair 160 causes the image receiving paper 108
Is pulled out of the tray 144 and the second roller pair 162
Wait for the photosensitive material 106 to arrive.

The first roller pair 160 and the second roller pair 1 are synchronized with the passage of the photosensitive material 106 through the guide plate.
The driving of the image receiving paper 108 is started.
4 and is conveyed to a third roller pair 166.

In the third roller pair 166, the photosensitive material 10
6 and the image receiving paper 108 are pinched in a superposed state, and sent out to the heat roller 174. At this time, the photosensitive material 10
Both are brought into close contact with each other by the water applied to 6.

The superposed photosensitive material 106 and the image receiving paper 108 are wound around a heat roller 174, receive heat from a heater 182, and undergo a thermal development transfer process. That is, the image recorded on the photosensitive material 106 is transferred to the image receiving paper 108 and visualized.

The heat development transfer is completed with the heat roller 174 wound about 1/3, and the image receiving paper 108 is
The photosensitive material 1 is separated by the peeling roller 184 and the peeling claw 186.
, And is discharged onto a discharge tray 140 so as to be wound around a peeling roller 184.

On the other hand, the photosensitive material 106 is
After being wrapped about 1/2 by 74, it moves tangentially and is taken up by the take-up reel 154.

As a result, an image can be formed with a compact structure, and the image to be recorded can be confirmed by the monitor section 114, so that the density and the color balance can be easily adjusted.

Next, the image forming process will be described with reference to FIGS. FIG. 9 shows an example of the image forming process according to the present embodiment.

When an image forming process according to the exposure pattern is instructed by operating the pattern execution key 117,
In step 300, an exposure pattern is captured.

When the exposure pattern is captured, in step 302, the sub-scanning amount is determined according to the exposure pattern. As a result, the overlapping area 450 composed of one main scanning line can be exposed by two main scanning exposures.

When the sub-scanning amount is determined, in step 304, digital image data is fetched. At this time, digital image data is assigned to all the LED chips 208.

When the digital image data is taken in, main scanning is started in step 306 and step 3
In step 08, execution of the exposure pattern is started. In step 310, it is determined whether or not the main scanning is completed. The determination is negative until the main scanning is completed, and the exposure processing according to the exposure pattern in the main scanning is continued. I do.

As shown in FIG. 8A, when the main scanning is started, the n-th main scanning along the main scanning direction W is performed. In the main scanning, when the exposure pattern starts to be executed, the LED chip 208 is turned on / off along the main scanning direction W in accordance with the exposure pattern, and a predetermined number of dots 452 at a predetermined position that becomes a part of the main scanning line are formed. Form. Therefore, after the n-th main scanning exposure, predetermined dots 452 are formed in the overlapping area 450 according to the exposure pattern, thereby forming a partial main scanning line. As a result, the shape of the overlapping area 450 on the downstream side in the sub-scanning direction P is uneven in the sub-scanning direction P and extends in the main scanning direction W (see the hatched portion in FIG. 8C).

When one main scan is completed, the judgment is affirmative, and in step 312 the sub-scan is performed with the adjusted and determined sub-scan amount. By this sub-scanning, the overlapping area 450 is arranged below the exposure area by the next main scanning exposure by the n-th main scanning. When the sub-scanning is completed, it is determined in step 314 whether or not there is a next main scanning line. If all the main scanning lines for forming a desired image have not been formed, the determination is affirmed, and the process proceeds to step 314. The flow shifts to 304, where digital image data for the next main scan is captured, and the next main scan is performed.

As shown in FIG. 8B, in the (n + 1) th main scanning exposure, the associated LED chip 2
08 is turned on / off along the main scanning direction W in accordance with the exposure pattern, and the dots 45 forming a part of the main scanning line
4 is formed at a position where the dot 452 is not formed in the overlapping area 450. Therefore, after the (n + 1) th main scanning exposure, one main scanning line including the dots 452 and the dots 454 is formed in the overlapping area 450. Since the dots 452 and the dots 454 are arranged in an uneven shape so as to mesh with each other to form a main scanning line, the dot 4
A line connecting the boundary between the dot 52 and the dot 454 extends in an uneven shape along the main scanning direction W (see FIG. 8C).

At this time, if an error occurs in the amount of movement in the sub-scan, the dots 452 that are meshed with each other
And the dot 454 are shifted in the sub-scanning direction W.
For this reason, the dots in the area other than the overlapping area 450 and the dots 452 and 454 in the overlapping area 450 are densely or coarsely arranged unevenly along the exposure pattern. As a result, the density difference caused by the unevenness of the interval between the dots occurs in an uneven shape along the exposure pattern. Therefore, even if there is an error in the amount of movement, no streak-like unevenness extending in the main scanning direction W occurs. Further, such unevenness is not noticeable as a whole.

As described above, a high quality image composed of main scanning lines continuous in the sub-scanning direction P is formed while performing two main scanning exposures on the overlapping area 450 in accordance with the exposure pattern.

On the other hand, if all the main scanning lines for forming the desired image are formed, and if there is no main scanning line that can be formed next, the judgment is denied, and a series of operations for forming the desired image are performed. Complete the process. When there are a plurality of desired images, a plurality of images can be similarly formed by repeatedly executing this routine.

As a result, even if there is an error in the amount of movement in the sub-scanning, the streak-like unevenness extending in the main scanning direction W is not conspicuous, so that a high quality image is efficiently formed without impairing the finished quality. be able to.

In the embodiment of the present invention, the overlapping region 450
Although one main scan line is used, the present invention is not limited to this.

FIG. 10 shows an example in which the number of main scanning lines in the overlapping area 450 is three.

In this case, the above-described exposure pattern is applied to three sets of LED chips 208 associated with each main scanning line. As shown in FIG. 10A, in this exposure pattern, three main scanning lines are formed by two main scanning exposures.

As shown in FIG. 10A, the dots 452 formed by the n-th main scanning exposure are arranged on the upstream side of the overlapping area 450 in the sub-scanning direction P, continuously to the non-overlapping area 451. One or two dots 452 of the main scanning line, or one or two dots 452 are arranged continuously from the dot 452 toward the downstream side in the sub-scanning direction P. For this reason, after the n-th main scanning exposure, in the overlapping area 450, the downstream end in the sub-scanning direction P is greatly uneven along the main scanning direction W due to the dots 452 that are continuous on the downstream side in the sub-scanning direction P. (See the hatched portion in FIG. 10C).

In the (n + 1) -th main scanning exposure, the dots 45 in the overlapping area 450 are continued from the non-overlapping area 451.
A dot 454 is formed in a place where 2 is not formed. For this reason, as shown in FIG.
The dots 454 are formed in an uneven shape so as to mesh with the unevenness of the dots 452 by the second main scanning, and three main scanning lines are completed. The boundary between the dots 452 and 454 has an uneven shape extending in the main scanning direction W while being largely cut in the sub-scanning direction P.

For this reason, even if an error occurs in the amount of movement during the sub-scan, between the overlapping pattern portions 452 and 454, between the dots 452 and 454 or between the dots 452 and 454 along the exposure pattern. Unevenness occurs in the space between the dots in the non-overlapping area in a more complicated uneven shape, and as a result,
By preventing the occurrence of streak-like unevenness extending in the main scanning direction W,
Finish quality is not further impaired.

Therefore, even if there is an error in the amount of movement during sub-scanning, a high-quality image can be efficiently formed without impairing the finished quality due to streak-like unevenness along the main scanning direction W. .

In the embodiment of the present invention, the case where an image is formed by a single exposure pattern has been described as an example. However, the exposure pattern can be changed for each main scan. As a result, even if an error in the amount of movement occurs during the sub-scanning, the unevenness in the interval between dots due to the error in the amount of movement becomes irregular in the sub-scanning direction P, making the density unevenness more conspicuous. It does not impair the finished quality.

In the embodiment of the present invention, the exposure pattern is a combination of on and off, but one dot 452 is formed by overlapping exposure by a pair of LED chips 208 corresponding to the main scanning line of the overlapping area 450. Can also. In this case, the light amount of the LED chip 208 is
A pair of LED chips 2 corresponding to each other so that dots of a light amount based on digital image data can be obtained by overlapping exposure.
08 is adjusted.

Therefore, in the n-th main scanning exposure,
Each LED chip 208 is main-scanned while changing the amount of light in the main scanning direction in accordance with the exposure pattern to form dots 452. The overlapping area 450 is defined by the dots 452.
In this case, an uneven density difference occurs in the main scanning direction. Next, after sub-scanning, in the (n + 1) th main scanning exposure, while changing the light amount according to the exposure pattern, n
The main scanning is performed so as to overlap the dots 452 formed by the second main scanning exposure to form dots 454. Due to the dots 454, a corresponding uneven density difference is generated by inverting the uneven density difference extending in the main scanning direction caused by the n-th main scanning exposure. These dots 452, 4
By overlapping the dots 54, dots having a light amount based on the digital image data are formed.

As described above, since the overlapping exposure is performed while changing the light amount in the main scanning direction according to the exposure pattern, dots of the light amount corresponding to the digital image data are formed in the overlapping area 450.

Therefore, even if an error occurs in the amount of movement during the sub-scanning, the boundary between the uneven density differences extending in the main scanning direction caused by each main scanning exposure is not uniform along the main scanning direction W. As a result, no line-shaped unevenness extending in the main scanning direction P occurs. In addition, since the dots 452 or 454 having different light amounts according to the exposure pattern are formed with a shift, the dots are continuous.
Thereby, an image can be formed without deteriorating the finished quality.

The overlapping area 450 is obtained by two main scanning exposures.
When the main scanning line is formed in an overlapping manner and the light amount of the LED chip 208 is set to 50% of the light amount of the digital image data in one main scanning exposure, if the light amount is large in the main scanning direction, the light amount becomes large. Since the unevenness based on the difference is not formed, it is preferable to reduce the number of continuous light amounts.

In the embodiment of the present invention, the boundary between the dot 452 and the dot 454 is made uneven, but the present invention is not limited to this. For example, not only continuous dots 452 and 453 but also discontinuous dots 452 and 453 may be included. In this case, by one main scanning exposure,
A dot 452 or a dot 454 is formed in a stepping stone shape. As a result, the dots 452, 4
Even if the formation position of 53 becomes more irregular and an error in the amount of movement occurs during sub-scanning, it is possible to further prevent the occurrence of streak-like unevenness extending in the main scanning direction W.

In the embodiment of the present invention, the position of the dot 452 to be formed in the exposure pattern can be determined by using, for example, a random number or the like, and such an exposure pattern is changed every main scanning. You can also. Thus, even if there is an error in the amount of movement during sub-scanning, the occurrence of streak-like unevenness extending in the main scanning direction W is further prevented, and the finish quality is not impaired.

In the embodiment of the present invention, the exposure in the overlapping area 450 when forming a desired image can be selected from any one of the above-mentioned dot 452 and 454 formation modes. And these formation modes can be used in combination. In this case, unevenness in the interval between dots in the overlapping area 450 of the desired image occurs more irregularly, and the occurrence of streak-like unevenness extending in the main scanning direction W can be further prevented.

In the embodiment of the present invention, the exposure pattern is set in advance, but the present invention is not limited to this. For example, it may be read from the optical disk 102 or the FD 104 every time the exposure process is performed.

[0116]

According to the present invention, in an overlapped main scanning line area by a predetermined sub-scanning amount of sub-scanning, an exposure dot formed by a previous main scanning and an exposure dot formed by a subsequent main scanning are selected. In accordance with the set exposure pattern, a large number of continuous exposure dots constituting the main scanning line are formed by two main scanning exposures. The unevenness in the interval is arranged along the exposure pattern, and the occurrence of streak-like unevenness extending in the main scanning direction can be prevented.

Accordingly, a high quality (high resolution) image can be efficiently formed without the finish quality being impaired by the stripe-like unevenness.

When the number of exposure dots in the overlapping main scanning line area formed in one sub-scanning direction in one main scanning is varied in the main scanning direction, this variation is reduced in the sub-scanning direction. Even if there is an error in the amount of movement in the sub-scanning, unevenness in the interval between the exposure dots occurs in the large unevenness in the sub-scanning direction. Generation can be further prevented.

Further, when the exposure dots formed by the overlapping exposure are selected and the exposure dots are formed by the overlapping exposure so as to have an exposure amount corresponding to the digital image data, the movement amount in the sub-scanning is reduced. Even if an error occurs, uneven density differences due to different exposure amounts are formed to be shifted along the exposure pattern according to the exposure pattern, so that it is possible to prevent the occurrence of unevenness extending in the main scanning direction.

[Brief description of the drawings]

FIG. 1 is a perspective view of an image forming apparatus according to an embodiment.

FIG. 2 is a front view of the image forming apparatus according to the embodiment.

FIG. 3 is a side sectional view showing an internal configuration of the image forming apparatus according to the present embodiment.

FIG. 4 is a front view illustrating a schematic configuration of an exposure unit.

FIG. 5 is a plan view showing a light source unit of the exposure unit.

FIG. 6 is a functional block diagram of a controller.

FIG. 7 is a conceptual plan view of a photosensitive material on which an image forming process has been performed according to an exposure pattern according to the present embodiment.

FIG. 8A is a conceptual diagram of an overlapping area by an n-th main scanning exposure according to an exposure pattern according to the present embodiment,
(B) is a conceptual diagram of an overlapping area by the (n + 1) th main scanning exposure that is overlaid on (A), and (C) is the nth and n +
FIG. 3 is a plan view of the photosensitive material on which the first main scanning exposure has been performed.

FIG. 9 is a flowchart illustrating an example of an image forming process according to the embodiment of the present invention.

FIG. 10A is a conceptual diagram of an overlapping area by an n-th main scanning exposure according to another exposure pattern according to the present embodiment, and FIG. 10B is an (n + 1) -th exposure that is overlaid on FIG. FIG. 2C is a plan view of a photosensitive material on which n-th and (n + 1) th main-scanning exposures have been performed.

[Explanation of symbols]

 Reference Signs List 100 image forming apparatus 106 photosensitive material 117 pattern execution key (light emission control means) 176 exposure unit 200 light source unit 202 controller 204 light source unit (exposure light source) 206 main scanning unit 208 LED chip (light emitting element) 226 stepping motor (main scanning means) 400 Exposure control unit 404 LED light amount control unit (light emission control unit) 408 LED light emission control unit (light emission control unit) 410 Main scanning control unit 412 Sub-scanning control unit (sub-scanning amount adjustment unit) 416 Motor (sub-scanning unit)

Claims (3)

[Claims] 1. An image forming apparatus, wherein an exposure light source and a photosensitive material are relatively moved in a main scanning direction and a sub-scanning direction, and a light beam from the exposure light source is scanned and exposed on the photosensitive material based on digital image data to form an image. An image forming apparatus, wherein the exposure light source has a plurality of light emitting elements arranged so as to emit a plurality of light beams along a sub-scanning direction, and a main scan for forming a plurality of main scan lines at the same time by a main scan. Exposure is performed, after one main scanning exposure, a sub-scanning amount adjusting means for adjusting a sub-scanning amount so that a plurality of main scanning lines overlap at the time of the next main scanning exposure, and the overlapping main scanning line area The exposure dots corresponding to the digital image data in the above are selectively set to the exposure dots formed in the previous main scan and the exposure dots formed in the subsequent main scan, so that the exposure according to the digital image data is performed. And a light emission control means for controlling light emission. 2. The exposure dot formed in the preceding main scan and the exposure dot formed in the subsequent main scan are each formed continuously in the sub-scanning direction. An image forming apparatus according to claim 1. 3. An image is formed by relatively moving an exposure light source and a photosensitive material in a main scanning direction and a sub-scanning direction, and scanning and exposing a light beam from the exposure light source on the photosensitive material based on digital image data. An image forming apparatus, wherein the exposure light source has a plurality of light emitting elements arranged so as to emit a plurality of light beams along a sub-scanning direction, and a main scan for forming a plurality of main scan lines at the same time by a main scan. Exposure is performed, after one main scanning exposure, a sub-scanning amount adjusting means for adjusting a sub-scanning amount so that a plurality of main scanning lines overlap at the time of the next main scanning exposure, and the overlapping main scanning line area In the exposure dots corresponding to the digital image data, the exposure dots formed so as to be overlapped in the previous main scan and the subsequent main scan are selectively set, and the exposure dots corresponding to the digital image data are performed by the overlapping exposure. Light emission control means for controlling light emission so as to obtain the same exposure amount,
An image forming apparatus comprising: