JPH10193675A - 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 on the occurrence of errors in the movement amount of a sub scan. SOLUTION: A sub scan amount is adjusted and determined in accordance with an exposure pattern to form an overlapping area 450 to which three main scan lines belong. Only an LED chip that can form a center line first among the three main scan lines is adapted to be turned on, and a main scan and exposure is carried out in accordance with the exposure pattern at the overlapping area 450. After a sub scan, an LED chip that can form remaining two main scan lines is turned on to carry out the main scan and exposure. In this manner, three main scan lines at the overlapping area 450 are formed in two main scans. Even when the sub scan includes an error in the movement amount, a distance between irregularities appearing like streaks in a main scan direction which is caused by a distance irregularity of the main scan lines is thinned to be unnoticeable as a whole at the overlapping area 450.

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.

[0005] 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 good finish quality with 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 is performed simultaneously by forming several main scanning lines by main scanning. After the scanning exposure, the sub-scanning amount adjusting means for adjusting the sub-scanning amount so that the plurality of main scanning lines overlap at the next main scanning exposure, and the light emitting element for exposing the overlapping main scanning line region, A light-emitting element to be turned on by scanning,
And a light emission control unit for selectively setting a light emitting element to be turned on in a subsequent main scan and controlling light emission so as to perform exposure according to the digital image data.

According to the present invention, by performing sub-scanning with the sub-scanning amount adjusted by the sub-scanning amount adjusting means, a plurality of main scanning lines are overlapped by two main scanning exposures, and an overlapping main scanning line area is provided. The light emitting elements to be turned on in the first main scanning and the light emitting elements to be turned on in the subsequent main scanning are selectively set from the light emitting elements to be exposed. Which of the light emitting elements is turned on in the first main scan or the second main scan may be set in advance, or may be set each time.
Thereby, the exposure pattern at the time of the main scanning exposure is determined. Based on this exposure pattern, first, the light emitting elements selected to be turned on in the previous main scan are turned on to form a predetermined number of main scan lines, and in the next main scan, the light is not selected for the previous main scan. The light emitting elements thus turned on form the remaining main scanning lines.

As a result, a plurality of boundaries between the current main scanning exposure and the previous or next main scanning exposure may be formed in the overlapping main scanning line area exposed in one main scanning exposure. Even if an error occurs in the amount of movement during sub-scanning and the amount of sub-scanning does not match the actual amount of movement, it is possible to reduce the interval at which the interval between main scanning lines varies. For this reason, even if an error occurs in the movement amount during the sub-scanning, the interval of the streak-like unevenness extending in the main scanning direction can be reduced, and the streak-like unevenness can be made inconspicuous as a whole.

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

According to a second 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 several main scanning lines are simultaneously formed by main scanning to perform main scanning exposure.After one main scanning exposure, a plurality of main scanning lines are provided at the next main scanning exposure. Sub-scanning amount adjusting means for adjusting the sub-scanning amount so that the main scanning lines overlap, and a light emitting element for exposing the overlapping main scanning line area,
Light-emitting control means for selectively setting a light-emitting element to be turned on in an overlapped manner in the previous main scan and the subsequent main scan, and controlling the light emission so as to have an exposure amount corresponding to the digital image data by the overlapping exposure. It is characterized by.

According to the present invention, a plurality of main scanning lines in an overlapping main scanning line area are provided with main scanning lines that are repeatedly exposed. This overlapping exposure
The main scanning line which becomes the exposure amount based on the digital image data by performing the double exposure is set each time or in advance, and thereby the exposure pattern at the time of the main scanning exposure is determined.
On the basis of this exposure pattern, in the overlapping main scanning line area, the main scanning line is formed by turning on the light emitting elements and performing the main scanning so that a predetermined exposure amount is obtained in the previous main scanning, and the next main scanning line is formed. In the scanning, the light emitting element is turned on so that the corresponding predetermined exposure amount is obtained, and the main scanning is performed, and the main scanning line is formed so as to overlap the already formed main scanning line.

Thus, a plurality of boundaries between the current main scanning exposure and the previous or next main scanning exposure can be formed in the area exposed by one main scanning exposure. When the amount and the actual movement amount are different from each other, it is possible to narrow the interval in which the interval between the main scanning lines varies. As a result, even if an error occurs in the movement amount during the sub-scanning, the interval between the streak-like unevenness extending in the main scanning direction can be reduced, and the streak-like unevenness can be made inconspicuous as a whole.

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

It is preferable that the light amount of the light emitting element to be repeatedly exposed is adjusted by 50% of the light amount according to the digital image data. Further, all of the plurality of main scanning lines in the overlapping area may be selected, or a part thereof may be selected. When all the main scanning lines are selected, the plurality of main scanning lines in the overlapping area are all exposed in an overlapping manner. The non-selected main scanning line may cause only one of the light emitting elements associated with the main scanning line to emit light.

The invention according to claim 3 is characterized in that the light emission control means selects and sets a light emitting element to be turned on for each main scan.

According to the present invention, the main scanning line to be exposed during the current main scanning exposure selected from the main scanning lines in the overlapping main scanning line area or the main scanning line in the overlapping main scanning line area is selected. Since the light emitting element corresponding to the main scanning line to be repeatedly exposed is selected for each main scanning, the pattern of the main scanning line in the overlapping main scanning line area can be changed for each main scanning. Thus, even if an error occurs in the amount of movement in the sub-scanning, the image formed in this way has irregular stripe-like unevenness caused by the difference in the interval between the main scanning lines, and is made less noticeable. As a whole, the stripe-like unevenness can be made inconspicuous.

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

[0018]

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 part 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 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 image receiving paper 108 is stored in a layer on a tray 144 in advance.
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, a second roller
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.

It should be noted that, 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, and a discharge tray is provided. 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 application piece 188 is made of a highly absorbent material such as felt or sponge and has a suitable 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 coated 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 be constantly supplied from outside the apparatus by providing a pipe.

In this embodiment, water is used as a solvent for image formation. However, this water is not limited to pure water but includes water in a sense that it is widely used. 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 light exposure unit 176 mainly includes a light source unit 200 provided above the conveyance 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 disposed on a support portion 215 at the center of the exposure casing 214 on the downstream side of the aperture 216, and collects predetermined light from the light source portion 204 so that an appropriate light is focused 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 always adjusted by an auto focus mechanism (not shown). Alternatively, it is possible to make adjustment unnecessary by using a lens system having a large depth of focus.

The light source unit 204 includes a pair of parallel guide shafts 21 that constitute 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 204 is
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.

The substrate 210 is provided with predetermined wiring by etching or the like. The wiring is covered with metal so as not to 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 fluctuation in the amount of light can be suppressed.

The dimensions of each section of the light source section 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.

The hatched portion of the LED chip 208 shown in FIG. 5 is a region where light is actually emitted. As shown by a chain line in FIG. ing.

By the light source unit 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.

Incidentally, as shown in FIG. 7, the image forming apparatus 100
A part of the area that can be exposed by the ED chip 208 is overlapped in the sub-scanning direction to form an overlap area 450.
At 50, an image forming process of forming an image while forming three main scanning lines in two main scans can be executed. For this purpose, an exposure pattern is set to selectively set whether to turn on the LD chip 208 capable of forming three main scanning lines in the overlapping area 450 in the first main scan or in the second main scan.

Here, of the overlapping area 450, an exposure pattern is set in which one in the center is formed by the n-th main scan and two at both ends are formed by the (n + 1) -th main scan (FIG. 8 ( A)). With this exposure pattern, the LED chips 208 that can form three main scanning lines in the overlapping area 450 are associated with each main scanning line.

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 the 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 the sub-scanning amount corresponding to the main scanning by the ten LED chips 208 in advance so that the exposure area by the light source unit 204 overlaps the three main scanning lines according to the input exposure pattern. Adjust and overlap area 45
The sub-scan amount corresponding to 0 is determined.

The exposure control section 400 is connected to an LED light quantity adjusting section 404.
In 04, an exposure pattern instructed to be executed is input from the exposure control unit 400. The LED light amount adjusting unit 404 controls the overlapping area 450 according to the input exposure pattern.
(See FIG. 7) of the three associated LED chips 208 capable of forming three main scanning lines, the LED forming the main scanning line selected for the nth main scanning exposure
The tip 208 is adjusted on in each set.
At this time, the LED chip 208 corresponding to the main scanning line selected for the (n + 1) th main scanning exposure is turned 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 8, the light emission of all the LED chips 208 provided in the light source unit 204, including the specified LED chip 208 turned on according to the exposure pattern, is controlled according to the digital image data.

Accordingly, in the image forming apparatus 100, the LED chip whose light amount is adjusted by a predetermined sub-scanning amount according to the operation of the pattern execution key 117 while overlapping a part of the exposure area according to the exposure pattern. The main scanning exposure is repeated by using the LED chip 208 of the light source unit 204 including the light source unit 208 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 predetermined number of lines, and the light source unit 204 is exposed at predetermined close intervals while moving along the width direction of the photosensitive material 106 while being guided by the guide shaft 218 by driving of the stepping motor 226. Do
A main scanning line composed of a number of dots 280 is formed.

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 photosensitive material 106 having a length corresponding to 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 water has been applied is guided by a guide plate 172 and conveyed to a third roller pair 166.

On the other hand, the image receiving paper 108 is a half-moon roller 156.
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 when the heat roller 174 is 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 unit 114, so that the density and 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-scan amount is adjusted according to the exposure pattern, and the adjusted sub-scan amount is determined. As a result, the overlapping area 4 composed of three main scanning lines
50 can be exposed by two main scans.

When the sub-scanning amount is determined, in step 304, three of the overlapping areas 450 are determined according to the exposure pattern.
Of the book main scanning lines, only the LED chips 208 corresponding to the main scanning lines selected to be formed by the current main scanning exposure are turned on. L corresponding to the main scanning line not selected to be formed by the current main scanning exposure
Adjust the ED chip 208 off.

LED chip 2 corresponding to overlapping area 450
08 is adjusted on or off, step 306
, Digital image data is captured. At this time, digital image data is assigned to all the LED chips 208. For this reason, the off-adjusted L
Digital image data is also assigned to the ED chip 208.

When the digital image data is captured, in step 308, the main scanning exposure is started.

As shown in FIG. 8A, when the main scanning exposure is started according to the exposure pattern, the associated LED chips 208 are turned on / off along the sub-scanning direction P. By the dot 4
51 are continuously formed in the main scanning direction W to form an n-th overlapping pattern 452. As a result, the central main scanning line selected to be formed in the n-th main scanning exposure among the main scanning lines in the overlapping area 450 is formed by the LED chip 208 adjusted to be on, and adjusted to be off. The portion corresponding to the LED chip 208 is blank.

When the main scanning exposure is started, step 31
At 0, it is determined whether or not the main scanning exposure has ended, and the determination is negative until the end.

When one main scan is completed, the judgment is affirmative, and in step 312 the sub-scan is performed by the adjusted and determined sub-scan amount. By this sub-scanning, the overlapping area 450 in which only the central main scanning line is formed by the n-th main scanning exposure is arranged in the exposure area by the next main scanning.

When the sub-scanning is completed, it is determined in step 314 whether 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 affirmative. Then, the process proceeds to step 306, where the digital image data for the next main scan is taken in, and the next main scan is performed.

As shown in FIG. 8A, by the main scanning exposure according to the exposure pattern, the LED chip 208 associated with the main scanning line selected to be formed in the (n + 1) th main scanning exposure is obtained. , Turned on and dot 4
53 are continuously formed in the main scanning direction W.
A + 1-th overlapping pattern 454 is configured. This n +
The first overlapping pattern 454 is formed by overlapping the nth overlapping pattern on the overlapping region 450 where the 452 is formed. As a result, two main scanning lines adjacent on both sides are formed in the central main scanning line by the dots 451 formed by the n-th main scanning exposure. As a result, of the three main scanning lines constituting the overlapping area 450, the central main scanning line is formed by n main scanning exposures, and the remaining main scanning lines are formed by n + 1 main scanning exposures. Is done.

At this time, as shown in FIG.
When an error occurs in the amount of movement during sub-scanning and the amount of sub-scanning differs from the actual amount of movement, the interval between the (n + 1) th main scanning line and the n-th main scanning line varies. FIG. 8B shows a case where the moving amount is smaller than the set amount. When the interval between the n-th main scanning line and the (n + 1) -th main scanning line is reduced, the (n + 1) -th dot 4
53 overlap, and in the overlapping area 450, the dot 453 by the (n + 1) th main scanning exposure overlaps with the dot 451 by the nth main scanning exposure (position Q and position S). Dot 4
Since 51 and the dot 453 have the same light amount,
The density of the overlapping portion (the position Q and the position S) increases (see FIG. 8C). On the other hand, in a portion where the main scanning line of the (n + 1) th time is shifted and the interval is increased (position R in FIG. 8B), the density is reduced because no dot is formed (see FIG. 8C).

For this reason, as shown at the position Q, the position S, and the position R, the interval between the main scanning lines varies, and
This variation occurs in a fine cycle. The unevenness of the interval causes streak-like density unevenness extending in the main scanning direction. However, the streak-like density unevenness generated at such a narrowed interval is inconspicuous as an entire image.

As described above, by continuously performing the main scanning exposure using this exposure pattern while repeating the sub-scanning, an image formed by the main scanning lines continuous in the sub-scanning direction is formed.

On the other hand, if all the main scanning lines for forming a desired image are formed, and there is no main scanning line that can be formed next, the determination is negative and a series of operations for forming a 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 when the sub-scanning amount and the moving amount at the time of performing the sub-scanning are different, a high-quality image can be efficiently formed without impairing the finished quality due to stripe-like density unevenness extending in the main scanning direction. can do.

In the embodiment of the present invention, the case where an image is formed with a single exposure pattern has been described as an example, but the exposure pattern does not have to be single.

FIG. 10 shows an example in which the LED chip 208 that is turned on first among the main scanning lines in the overlapping area 450 is selected and changed for each main scanning. Thus, the previously formed main scanning line is changed every main scanning. It should be noted that in FIG.
5, the shaded portion is the LED chip 208 adjusted to be ON.
Indicates a portion where a main scanning line is formed.

In this image forming process, since the exposure pattern is changed every main scanning, the LED chip 208 which is turned on / off in the n-th main scanning exposure has n
It is adjusted on / off / off in the + 1st main scanning exposure. For this reason, in the overlap region 450 formed by the n-th and (n + 1) th main scanning exposures, the central one of the three main scanning lines is formed first, but the overlap is caused by the (n + 1) th and (n + 2) th main scanning exposures. In the area 455, one of the three main scanning lines on the upstream side in the sub-scanning direction is formed first.

When an image is formed by using a different exposure pattern for each main scan, even if an error occurs in the sub-scan, the interval (period) at which the interval between the main scan lines varies will be reduced and the main scan line will be formed. Generate differently for each scan.

As a result, variations in the intervals between the main scanning lines are generated at different periods for each main scan, so that irregular stripe-like density unevenness can be made even more inconspicuous.

Such an exposure pattern is formed in the overlapping area 45.
In order to select a main scanning line to be formed first at 0 and 455, for example, a random number or the like can be applied. Accordingly, it is possible to prevent the pattern from being repeated at a constant cycle, and to make the appearance cycle of the streak-like density unevenness irregular so as to be less noticeable.

A single exposure pattern that is repeatedly applied and an exposure pattern that can be changed for each main scan can be selectively set. In this case, it is possible to provide a selecting means for selecting an arbitrary exposure pattern.

Although the number of main scanning lines belonging to the overlapping area 450 is set to three, it is not limited to this. The same effect as described above can be obtained as long as the overlapping area 450 includes at least two main scanning lines. However, by increasing the number of main scanning lines belonging to the overlapping area 450, the number of main scanning lines formed at one time decreases. Therefore, the number of main scanning lines to which the overlapping area 450 belongs is determined from the viewpoint of processing efficiency. . However, when two main scanning lines belong to the overlapping area 450, the main scanning line on the downstream side in the sub-scanning direction P is formed first.

In the present embodiment, the case where the exposure pattern is adjusted so that the light amount of the pair of LED chips 208 is turned on and off is described. However, the present invention is not limited to this.

FIG. 11 shows an example of an exposure pattern in which the light amount of the corresponding pair of LED chips 208 is adjusted so that the light amount based on the digital image data is obtained by performing double exposure.

In this exposure pattern, the dots 460 of the n-th side pattern 452 are formed by the n-th main scanning exposure, and the dots 464 of the (n + 1) -th pattern 454 are formed by the (n + 1) -th main scanning exposure. LED chip 2 forming these dots 460 and dots 464 respectively
08 and the corresponding light amount of the LED chip 208 are:
The light amount is added based on the overlapping exposure and becomes the light amount based on the digital image data. Note that a pair of Ls that correspond to each main scanning line and form dots 460 and 464 are formed.
The light amount of the ED chip 208 is equivalent to
As long as the amount of light is the same as that of the LED chip 208 forming No. 2, the light amount may be different or the same.

For this reason, by performing the overlapping exposure by the n-th and (n + 1) th main scanning exposures, the overlapping area 45 is obtained.
In the case of 0, the dots 460 and 464 are formed so as to overlap each other and have a predetermined exposure amount. Thereby, the overlapping area 450
Are formed at the same density as the main scanning lines in other areas, and an image having a uniform density can be formed.

In this case, even if an error in the amount of movement occurs during sub-scanning, the dots 460, 464, and 46
The density difference caused by overlapping of any two of the two is small.

Further, a pair of corresponding LED chips 208
In the case where the light amounts of the dots 460 and 464 and the dots 462 overlap with each other, the density can be set to about 1.5 times the density of the dots 462 when the same light amount is used, that is, when the light amount is 50%. The density difference can be reduced. on the other hand,
When the light amounts of the corresponding pair of LED chips 208 are different, the dots 460, 464, and the dots 462
As a result, the density difference in the overlapping region 450 can be generated more finely and continuously.

As a result, streak-like density unevenness extending in the main scanning direction W can be made more inconspicuous.

In the exposure pattern for adjusting the light amount of the pair of LED chips 208, the number of main scanning lines belonging to the overlapping area 450 is three, but the present invention is not limited to this. If at least two main scanning lines belong to the overlapping area 450, the total light quantity of the corresponding pair of LED chips 208 is made equal to the light quantity of the LED chips 208 in the other areas, and the same effect as described above is obtained. Can be obtained.

In this exposure pattern, when the light amount of the corresponding pair of LED chips 208 is different, the light amount can be changed for each main scan. This makes it possible to make the appearance cycle of the streak-like density unevenness extending in the main scanning direction generated when the moving amount and the sub-scanning amount are different from each other more irregular so that such density unevenness is less noticeable. it can.

In one main scanning exposure, all the main scanning lines belonging to the overlapping area 450 can be formed with the same light amount, and these main scanning lines can be formed with different light amounts. . In any case, the same effect as described above can be obtained.

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.

[0121]

According to the present invention, by performing sub-scanning with the sub-scanning amount adjusted by the sub-scanning amount adjusting means, the main scanning lines in the overlapping main scanning line area can be scanned by either of the two main scannings. Therefore, a plurality of boundaries between the current main scanning exposure and the previous or next main scanning exposure can be formed in a region exposed by one main scanning exposure, and sub-scanning is performed. Even if there is an error in the movement amount at that time, it is possible to narrow the interval at which the interval between the main scanning lines varies.
Therefore, even if an error occurs in the movement amount during the sub-scanning, the streak-like unevenness extending in the main scanning direction is inconspicuous, and the finished quality is not further impaired. Further, thereby, a high-quality (high-resolution) image can be efficiently formed.

Further, since the main scanning line to be exposed by overlapping exposure is provided in the main scanning line area to be exposed repeatedly, the main scanning line to be exposed in one main scanning exposure is set to the current main scanning exposure. A plurality of boundaries between the time and the previous or next main scanning exposure can be formed, and even if the sub-scanning amount and the actual movement amount when performing the sub-scanning are different, the interval of the main scanning line varies. Can be reduced. High image quality (high resolution) without loss of finish quality
Can be efficiently formed.

Further, in the above invention, the light emitting element which is turned on during the current main scanning exposure selected from the main scanning lines in the overlapping main scanning line area, or the light emitting element selected from the main scanning lines in the overlapping main scanning line area is selected. Since the light emitting element corresponding to the main scanning line to be overlap-exposed is selected for each main scanning, the image formed in this manner extends in the main scanning direction even if the sub-scanning amount and the actual moving amount are different. Streak-like irregularities become irregular and can be made less noticeable.

[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 dots formed according to the exposure pattern according to the present embodiment, FIG. 8B is a partially enlarged view of the case where dots are overlapped in FIG.
(C) is a diagram showing the density change of (B).

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

FIG. 10 is a conceptual diagram of a photosensitive material on which an image forming process is performed according to another exposure pattern according to the embodiment of the present invention.

FIG. 11 is a conceptual diagram of dots formed according to another exposure pattern according to the embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 image forming apparatus 106 photosensitive material 108 image receiving paper 117 pattern execution key (light emission control means) 176 exposure unit 178 water application 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 unit) 400 Exposure control unit 404 LED light amount adjustment 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 means)

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. In the image forming apparatus, the exposure light source is provided with a plurality of light emitting elements so as to emit a plurality of light beams along the sub-scanning direction, the main scanning is formed by several main scanning lines at the same time. A sub-scanning amount adjusting means for adjusting a sub-scanning amount so that a plurality of main scanning lines overlap at the next main scanning exposure after one main scanning exposure; For the light-emitting elements that expose the scanning line area, light-emitting elements that are lit in the first main scan and light-emitting elements that are lit in the subsequent main scan are selectively set, and light is emitted so as to be exposed according to the digital image data. Control An image forming apparatus comprising: a light emission control unit. 2. 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. In the image forming apparatus, the exposure light source is provided with a plurality of light emitting elements so as to emit a plurality of light beams along the sub-scanning direction, the main scanning is formed by several main scanning lines at the same time. A sub-scanning amount adjusting means for adjusting a sub-scanning amount so that a plurality of main scanning lines overlap at the next main scanning exposure after one main scanning exposure; For the light emitting elements that expose the scanning line area, the light emitting elements to be turned on in the first main scan and the subsequent main scan are selectively set, and the light is emitted so that the exposure amount according to the digital image data is obtained by the overlapping exposure. An image forming apparatus, comprising: a light emission control unit that controls the light emission. 3. The image forming apparatus according to claim 1, wherein the light emission control unit selects and sets a light emitting element to be turned on for each main scan.