JPH0679918A - Image forming device - Google Patents

Abstract

PURPOSE:To form an image at high speed in an image forming device and reduce the dimensions of said device. CONSTITUTION:An image forming device has a plurality of exposing means for permitting exposure at different places on a photosensitive material 21 and a plurality of developing means which convert each of the latent images formed on the photosensitive material by the exposing means into a developed image and which are provided correspondingly to the respective exposing means. In this device, one of two kinds of the exposing means is made to the type of laser exposing means 23, 26 that irradiate a laser beam emitted from a semiconductor laser onto the photosensitive material through a deflecting system and an optical system. Further, the other kind is made to a third exposing means 29 formed by an LED arrary to irradiate dot light emitted from LEDs arranged in the form of a line to the photosensitive material. Thus, an image is formed for each line in the vertical scanning direction by the developing means corresponding to these exposing means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus such as a copying machine or a printer, and more particularly to an image forming apparatus provided with a plurality of exposing means and a plurality of developing means corresponding to each of the exposing means. It relates to the device.

[0002]

2. Description of the Related Art FIG. 10 is a front view showing a conventional image forming apparatus. FIG. 10 shows a digital two-color copying machine provided with a plurality of exposing means and a plurality of developing means corresponding thereto.

An automatic document feeder (ADF) 1 is installed at the top of the main body of the copying machine, and a document reading device 2 is installed below the automatic document feeder 1. In the main body of the copying machine provided below this, the first exposure device 4, L using a semiconductor laser, centering around the photosensitive drum 3,
A second exposure device 5 using an ED array, a first color (black) developing device 6, and a second color (red) developing device 7 are installed so as to surround the drum periphery.

Automatic document feeder 1 and document reader 2
A contact glass 8 on which a document is placed is arranged between the two. Further, the document reading device 2 includes an illumination lamp 9, mirrors 10, 11, and 12, a solid-state image sensor 13, and an image forming lens 14.

After inputting copy data such as the number of copies by operating the ten-key pad (not shown) of the operation unit, when the copy start button is pressed in the same manner, the originals placed on the automatic original feeder 1 are fed one by one. It is supplied onto the contact glass 8 of the document reading device 2. The illumination lamp 9 and the mirrors 10 and 1
An image of the document is read by the solid-state imaging device 13 by moving the documents 1 and 12 integrally and scanning and exposing the document.

The solid-state image pickup device 13 color-separates an image of a document and converts it into electric signals of respective colors. Then, the image data of each color read by the document reading device 2 is converted by the image processing unit and then output to the exposure device. However, here, the image data of the second color is once stored in the memory, and then the second color image data is stored at a timing later than the image data of the first color.
Is output to the exposure device 5.

The electrostatic latent image formed on the photoconductor 3 by the first exposure device 4 is visualized by the first developing device 6 and formed on the photoconductor 3 by the second exposure device 5. The formed electrostatic latent image is visualized by toner development of the second developing device 7. The transfer paper picked up from the paper feed tray 15 by the paper feed roller 16 has its leading end aligned by the registration roller 17, and is sent to the transfer portion at the same timing as the movement of the visible image (toner image) formed on the photoconductor 3. To be

When the visible image formed on the photoconductor 3 reaches the position facing the transfer charger 18, it is transferred to the transfer paper conveyed by the electrostatic attraction force. The transfer sheet on which the visible image has been transferred is conveyed by the conveyor belt 19, and is fixed by applying heat and pressure on the fixing roller 20, and then discharged.

By the way, in the image forming apparatus using the electrophotographic method, several methods are used in order to obtain the gradation of the image. For example, in the case of an image forming apparatus equipped with an exposure device using a semiconductor laser, there is one that changes the exposure time per dot or the exposure power according to a gradation signal from an image processing section.

[0010]

However, in the above-mentioned prior art, there is a limit to the resolution of the exposure time and the exposure power (for the exposure time, the higher the image forming speed, the more per dot). However, since the exposure time becomes shorter, the resolution becomes worse.), But the number of gradations was limited.
Also, under the same process conditions (charge potential, toner concentration, toner charge amount, development bias, etc.), there is a limit to what can be done by changing only the exposure conditions (time and power) from the low density portion to the high density portion. (For example, under certain process conditions, the resolution of the exposure conditions in the low density area was insufficient,
In some cases, gradation may not be obtained in the low density area).

Further, it has been difficult to stably obtain the image density from the low density portion to the high density portion even with the passage of time (usually, the maximum density is controlled so that the maximum density can be stably obtained. However, due to environmental changes and changes in photoreceptor characteristics,
Midtone due to deterioration of the developer, etc., especially the density in the low density part changes).

Further, when aiming at high-speed image formation, a deflector (polygon scanner) is used in an exposure apparatus using a laser.
The limitation on the number of revolutions (15,000 rpm when using a ball bearing as the bearing, 40,000 rpm when using an air dynamic pressure bearing) and the limitation on the modulation frequency of the laser are bottlenecks.

In addition, many originals to be copied have a mixture of characters and lines and picture portions such as photographs. At present, the character area and the picture area in the document can be separated by the reading device and the image processing section.
Then, the image processing section sends signals corresponding to the character area and the picture area to the exposure device, and the latent image is formed by the exposure device. However, since the latent image is formed by the same exposure device, only the same dot shape can be recorded in both the character area and the picture area (to make the character area sharper and the picture area higher gradation). , It is better that the dot diameter of the character part is smaller than that of the design part).

The present invention has been made in view of the above-mentioned circumstances of the prior art, and an object thereof is to provide an image forming apparatus capable of achieving high speed and small size of image formation.

[0015]

In order to achieve the above object, the present invention provides a plurality of exposing means for exposing different positions on a photosensitive member, and a latent layer formed on the photosensitive member by the exposing means. In an image forming apparatus provided with a plurality of developing means provided corresponding to each of the exposing means for visualizing each of the images, the exposing means passes a laser beam of a semiconductor laser through a deflector and an optical system. Laser exposure means for irradiating the photoconductor to the photoconductor, and array exposure means for irradiating the photoconductor with the dot light formed by the light emitters and optical shutters arranged in a line, and correspond to these exposure means. The image is formed line by line in the sub-scanning direction by the developing means.

In order to simplify the structure, a means for reading the image of the original read by the reading means into a character portion and a pattern portion is provided, and each of the range determined to be the character portion and the range determined to be the pattern portion is provided. Can be imaged by different exposure means.

In order to miniaturize the apparatus, at least one of a plurality of exposure means is equipped with a semiconductor laser, and laser exposure is performed by irradiating a photoconductor with a laser beam from the semiconductor laser via a deflector and an optical system. The other means is an array-like exposure means for irradiating the photosensitive member with dot light formed by light-emitting bodies or optical shutters arranged in a line, and the range determined to be the pattern portion is The laser exposure means may be used for exposure, and the area determined to be the character portion may be exposed by the array-shaped exposure means.

In the means for reducing the memory capacity, the latent image forming position on the photosensitive member for the exposure of the range determined as the character is downstream of the latent image forming position by the exposure of the range determined as the pattern portion. It is achieved by making it to the side.

[0019]

According to the above-mentioned means, at least the exposing means is a laser exposing means for irradiating the photosensitive member with a laser beam of a semiconductor laser through a deflector and an optical system, and light-emitting bodies and light arranged in a line. An image forming device is provided for each line in the sub-scanning direction by the developing device corresponding to the two types, that is, an array exposure device that irradiates the photosensitive member with the dot light formed by the shutter. Therefore, the linear velocity of the photosensitive member and the linear velocity of the paper sheet can be increased as compared with the conventional case, and the copying speed can be increased.

Further, by reading the character area and the picture area of the original image and exposing each area by a separate exposure device, the flow of signals can be simplified and the structure can be simplified.

Further, as one of the exposing means, an array exposing means for irradiating the photoconductor with the dot light formed by the light emitting bodies or optical shutters arranged in a line is used.
By performing the exposure in the range determined to be the character portion, the mechanical driving unit can be eliminated, and the device can be downsized.

Then, the latent image forming position on the photoconductor for the exposure of the range judged as the character is made downstream from the latent image forming position by the exposure of the range judged as the pattern portion, so that the buffer memory is The amount of exposure of the pattern portion is sufficient, the memory capacity can be reduced, and the cost can be reduced.

[0023]

1 is a block diagram showing a control system of an image forming apparatus according to the present invention, and FIG. 2 is a front view showing a structure of a main portion of a mechanical portion of the image forming apparatus according to the present invention.

First, the mechanical section of FIG. 2 will be described. The image forming apparatus shown here is a digital three-color copying machine.
In the figure, 21 is a photosensitive drum on which an electrostatic latent image is formed, 22
Is a first charging charger for uniformly charging the surface of the photoconductor drum 21 before the formation of a latent image, and 23 is a first exposure device for forming a latent image on the photoconductor drum 21 using a semiconductor laser. Reference numerals 24 and 24 are first developing devices provided with black toner to perform black development on the latent image.

Further, 25 is a second charger for charging the photosensitive drum 21 before the second exposure, and 26 is a second charger for exposing a color other than black using a semiconductor laser.
Exposure apparatus 27, a revolver type developing apparatus 27 which is a second developing apparatus having developing units for black, red, blue and green toners, and 28 charges the photosensitive drum 21 before the third exposure. The third charging charger 29 is a third exposure device using an LED array, and 30 is a slide type developing device as a third developing device having red and blue developing devices, respectively.

Further, 31 is a paper feed tray in which a large number of papers corresponding to the copy size are stored, and 32 is a paper feed tray 3.
1 is a sheet feeding roller for feeding the uppermost sheet, 33 is a registration roller for temporarily stopping the sheet fed by the sheet feeding roller 32 for adjusting the transfer timing, and 34 is a toner image on the photosensitive drum 21. A transfer charger for transferring the recording paper onto the recording paper, a conveyer belt 35 for discharging the recording paper after the transfer, and a fixing device 36 for fixing the toner image attached to the recording paper onto the recording paper. Further, C is a cleaning device for cleaning the residual toner adhering to the photosensitive drum 21.

In the image forming apparatus shown in FIG.
Similarly to the image forming apparatus shown in FIG. 0, it is usually possible to form an image of three colors. Here, a case of forming an image of three colors will be described with reference to the block diagram shown in FIG.

The control system shown in FIG.
7, an image processing unit 38, a printer unit 39, a system controller 40 for controlling them, and an operation panel 41.

The image reading section 37 includes three CCDs 42.
a, 42b, 42c, A / D connected to each of these
It is composed of converters 43a, 43b, 43c, a shading correction circuit 44 that performs shading correction on the outputs of these A / D converters, and a buffer memory 45 connected to this shading correction circuit 44.

The image processing section 38 performs a gamma correction on the output signal of the buffer memory 45, a γ correction circuit 46, a black separation / RGB generation circuit 47 for generating an RGB signal from the output signal of the γ correction circuit 46, and A gradation processing circuit 48 connected to the black separation / RGB generation circuit 47, a selector 49 connected to the gradation processing circuit 48, and a selector 49.
Is composed of buffer memories 50a and 50b connected to.

The printer unit 39 further includes a laser driver 51a connected to the buffer memory 50a, a laser driver 51b connected to the selector 49, an LED array (LEDA) driver 52 connected to the buffer memory 50b, and an LED array (LEDA). ) Third exposure device 29 connected to driver 52, second exposure device 26 connected to laser driver 51a, and laser driver 51
It comprises a first exposure device 23 connected to b.

In the above structure, first, the operation panel 4
Operate the predetermined operation button 1 to set the image formation color (black, red,
Set up to 3 colors such as blue). For the first and second colors, the photo mode or the character mode is set according to the original. Further, after setting the number of prints, the scaling factor, etc., and pressing the copy start button on the operation panel 41, the data is input to the system controller 40.

Then, the start signal, the synchronizing signal, and the magnification designation signal are sent to the image reading section 37 and the printer section 39, the image processing mode designation signal (color signal, photograph / character mode signal) is sent to the image processing section, and The system controller 40 receives an abnormal signal or an operation status signal (wait: wait, ready: ready, busy: busy, stop: stop) from each module.
The system controller 40 controls the entire system. Then, the printer unit 39 receives the first and second signals shown in FIG.
By using the electrophotographic processes of the second and third charging, exposing and developing, images of maximum three colors are formed on the transfer paper.

In the image reading section 37, the document is scanned at a scanning speed corresponding to the scaling ratio designated by the start signal from the system controller 40, and the image of the document is read in R, G, B (or Y, M). , C) and read by CCD 42a, 42b, 42c through A / D
After A / D conversion by the converters 43a, 43b, 43c and shading correction by the shading correction circuit 44, data is sent to the image processing unit 38. In the image reading unit 37, the buffer memory 45 synchronizes with the image processing unit 38.

Then, in the image processing section 38, the gradation of the data sent from the image reading section 37 is changed by the γ correction circuit 46 according to the characteristics of the photoconductor 21 and the developing device. After that, the black separation / RGB generation circuit 47 creates data of each color of black (Bk), red (R), blue (B), and green (G). Furthermore, the system controller 4
The image processing mode designation signal (color signal,
Gradation processing is performed by a photograph / character mode signal), and one of image data sent to the first to third exposure devices of the printer unit 39 is selected by the selector 49.

The buffer memories 50a and 50b are
The image data sent to the second exposure device 26 and the third exposure device 29 is transferred between the exposure position by the first exposure device 23 and the exposure position by the second exposure device 26 and the third exposure device 29 on the photoconductor. It functions to shift by the interval.

Next, an example will be described in which an image of the same color on a document is read by the document reading device 2 and an image is formed by another exposure device and a developing device depending on the density area of the image. Here, first, problems in the case of forming an image by a conventional set of an exposure device and a developing device will be described.

FIG. 3 is a characteristic diagram showing the relationship between the number of gradations in exposure (the gradation is changed by changing the amount of light and the lighting time) and the image density.

The desirable relationship is the characteristic i in the figure. However, the characteristic ii in the figure may change due to changes in the characteristics of the photoconductor or deterioration of the developer.
Or, it shifts to the relationship indicated by the characteristic iii (usually, the density of the pattern image formed on the photoconductor is detected, and the light amount is changed to control the maximum density: Dmax to be constant. Does not change much). That is, the density of the original and the density of the image change in the low density portion and the intermediate density portion. In particular, the change in the low-density portion is advantageous as the image quality, and the characteristic ii highlights and the characteristic iii
Then it becomes dirt.

Therefore, the present invention is intended to always obtain a stable image by separately providing an exposure device for forming an image of a low density portion and an image of a middle to high density portion and a developing device. First, when a monochrome and black image formation is set from the operation panel 41 shown in FIG. 1, this data is sent from the system controller 40 to the printer unit 39 and the revolver developing device 27 of FIG. Image formation is possible.

Further, the contents of the gradation processing circuit 48 and the selector 49 are changed by the signal from the system controller 40 to the image processing section 38, and the laser driver 51b of the first exposure device 23 and the laser driver 51a of the second exposure device 26 are changed.
The image data to be sent to is determined. Further, from the system controller 40 to the charging devices 22 and 25, the developing device 2
The image forming conditions are changed by sending a developing bias setting signal to Nos. 4 and 27.

Then, the first exposure device 23 and the developing device 24 form an image in the range of image densities D1 to Dmax as shown in FIG. Further, the second developing device 26 and the black developing device of the second developing device 27 form an image in the image density range of 0 to D1 as shown in FIG.

Here, as a supplement, an example of changing the density range of image formation will be described. Before that, the configuration of the control system between the system controller 40 and the developing device and the charging device will be described with reference to FIG.

A developing bias control circuit 53 is connected between the system controller 40 and the first developing device 24,
A charging voltage control circuit 54 is connected to the second charging charger 25, a laser light amount control circuit 55 is connected to the second exposure device 26, and a developing bias control circuit 56 is connected to the second developing device 7. Are connected.

First, in order to change the relationship between the number of gradations and the image density shown in FIG. 3 to the relationship shown in FIG. 4, the developing bias control circuit 53 is controlled by a signal from the system controller 40 as shown in FIG. Then, the developing bias of the first developing device 24 may be changed in the direction of increasing the developing potential. Further, in order to change to the relationship of FIG. 5, the charging voltage control circuit 54 and the developing bias control circuit 56 are controlled by a signal from the system controller 40, and both the second charging voltage and the developing bias of the second developing device 7 are controlled. The laser light amount control circuit 5 shifts the absolute value to a smaller value.
5 is controlled so that the image density becomes D1 when the exposure dose is "255".

Next, an example of the structure for increasing the copying speed by forming the same color by the first and second exposure / developing devices will be described. As described above, in an apparatus including an exposure apparatus that currently uses a laser beam, the upper limit of the copying speed is determined by the drive frequency of the laser and the rotational speed of the polygon scanner.

Therefore, as shown in FIG. 7, the image formation by the first exposure device 23 and the image formation by the second exposure device 26 are performed for each line, and the driving frequency of the laser and the rotation speed of the polygon scanner are changed. Without the photoconductor linear velocity, paper feed linear velocity,
By doubling the linear velocity of paper conveyance and the linear velocity of fixing, a double copying speed can be obtained. The signal flow will be described with reference to FIG.

FIG. 8 is a block diagram showing a motor control system.

In FIG. 8, a motor control circuit 57 connected to the system controller 40, a main motor 58 and a sheet feeding motor 59 connected to the motor control circuit 57 are added to the main part of the configuration shown in FIG. The added configuration is shown.

When the high speed copy mode is set from the operation panel 41, the signal is input to the system controller 40. Then, a signal is output from the system controller 40 to the selector 49 of the image processing unit 38, and the selector 49
Thus, the odd-numbered image data is input to the laser driver 51b of the first exposure device 23, and the even-numbered image data is input to the laser driver 51b of the second exposure device 26 via the buffer memory 50a. Furthermore, the system controller 4
The synchronization signal from 0 determines the timing of the image data output from the buffer memory 50a to the laser driver 51b of the second exposure device 26.

Further, a signal from the system controller 40 is input to the motor control circuit 57, and the photosensitive member, the developing device,
The number of rotations of the conveyance belt, the main motor 58 that drives the fixing device, and the paper feed motor 59 is doubled.

Next, the image data read by the document reading device 2 is separated into a character area and a picture area, different gradation processing is applied to the character area and the picture area, and the image formation of the picture area is shown in FIG. The second exposure device 26 is used.
The configuration for forming an image of a character area by the third exposure device 29 shown in FIG. 2 will be described below with reference to FIG.

FIG. 9 is a block diagram showing details of the image processing section for forming an image of the character area. The description of the same parts as shown in FIG. 1 will be omitted.

An image separation circuit 60 is connected to the black separation / RGB generation circuit 47, and its output signal is applied to the gradation processing circuit 48.

The black image data generated by the black separation / RGB generation circuit 47 of the image processing unit 38 is input to the image area separation circuit 60 and the gradation processing circuit 48. The image area separation circuit 60 determines whether it is a character or a pattern from above the pixels on the upper, lower, left and right sides, and transmits the result to the gradation processing circuit 48 as information. Then, the gradation processing circuit 48 converts the data into binary (1 bit) data in the case of a character, and into the 256 value (8 bit) data in the case of a pattern by dithering or the like. Then, the 8-bit data of the pattern portion is temporarily stored in the laser driver 51a of the second exposure device 26, and the 1-bit data of the character portion is temporarily stored in the buffer memory 50b, and then stored in the LEDA driver 52 of the third exposure device 29. Sent.

As the exposure device, there are a laser scanning device using a laser beam, a polygon scanner, an fθ lens, etc. as shown in FIG. 2, and an array-like optical writing device using an LED array or a light source and a liquid crystal shutter as an optical shutter. . The array-type optical writing device has an advantage that the optical system is simpler than that of the laser scanning device and can be downsized, and that it has high mechanical reliability because it has no mechanical driving unit.

However, on the other hand, there is a drawback in that the number of gradations cannot be obtained as much as the laser scanning device due to manufacturing problems and driving system problems. Therefore, as described above, since the gradation number of the character portion is binary, the image formation of the character portion can be made smaller by using the array-shaped optical writing device. Further, by using the array-shaped optical writing device as the downstream exposure device that uses the buffer memory, the number of memories can be reduced and the cost can be reduced.

Further, since the third charging device and the developing device for forming an image in the character region are binary images, some of the charging potential, the developing bias, and the LED light amount are changed to change the image. Stability can be increased (for example, by widening the charging potential and the developing bias potential, the margin for background stain is increased, the developing potential is increased, and the exposure amount is increased to obtain stable density).

[0059]

Since the present invention is configured as described above, it has the following effects.

In the image forming apparatus of the present invention, a plurality of exposing means for exposing different positions on the photoconductor, and each of the latent images formed on the photoconductor by the exposing means are visualized. In an image forming apparatus provided with a plurality of developing means provided corresponding to each of the exposing means, the exposing means irradiates a laser beam of a semiconductor laser onto the photoconductor through a deflector and an optical system. Means and array exposure means for irradiating the photoconductor with dot light formed by light emitters and optical shutters arranged in a line, and one line in the sub-scanning direction by the developing means corresponding to these exposure means. Since the image formation is performed for each time, the linear velocity of the photosensitive member and the linear velocity of the paper conveyance can be increased as compared with the conventional case, and the copying speed can be increased.

In the image forming apparatus according to the second aspect, there is provided a means for reading the image of the document read by the reading means into the character portion and the pattern portion, and the range determined as the character portion and the range determined as the pattern portion are provided. Since the image formation for each is performed by different exposure means, the configuration can be simplified and the cost can be reduced.

In the image forming apparatus of the third aspect, at least one of the plurality of exposing means includes a semiconductor laser, and the laser beam from the semiconductor laser is applied to the photoconductor through the deflector and the optical system. Another is laser exposure means, and the other one is array exposure means for irradiating the photosensitive member with dot light formed by light emitters or optical shutters arranged in a line, and is determined as the pattern portion. The area exposed is exposed by the laser exposure means, and the area determined to be the character portion is exposed by the array exposure means. Therefore, the mechanical drive section can be eliminated and the apparatus can be downsized. .

According to another aspect of the image forming apparatus of the present invention, the latent image forming position on the photoconductor for the exposure in the range determined as the character is more than the latent image forming position by the exposure in the range determined as the pattern portion. Since it is located on the downstream side, the memory capacity can be reduced, and as a result, the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a control system of an image forming apparatus according to the present invention.

FIG. 2 is a front view showing a configuration of a main part of a mechanical section of the image forming apparatus according to the present invention.

FIG. 3 is a characteristic diagram showing the relationship between the number of gradations in exposure and image density.

FIG. 4 is a characteristic diagram showing a relationship between image density and the number of gradations when an image is formed by the first exposure device and the first developing device.

FIG. 5 is a characteristic diagram showing a relationship between image density and the number of gradations when an image is formed by the second exposure device and the third exposure device.

FIG. 6 is a block diagram showing a configuration of a control system between a system controller according to the present invention and a developing device and a charging device.

FIG. 7 is an explanatory diagram showing a state of image formation by the first exposure apparatus and the second exposure apparatus according to the present invention.

FIG. 8 is a block diagram showing a motor control system.

FIG. 9 is a block diagram showing a configuration of an image processing unit for performing image formation on a character area.

FIG. 10 is a front view showing a conventional image forming apparatus.

[Explanation of symbols]

 21 Photoreceptor Drum 22 First Charging Charger 23 First Exposure Device 24 First Developing Device 25 Second Charging Charger 26 Second Exposure Device 27 Second Developing Device (Revolver Developing Device) 28 Third Charger charger 29 Third exposure device 30 Third slide type developing device 34 Transfer charger 36 Fixing device 37 Image reading part 38 Image processing part 39 Printer part 40 System controller 41 Operation panel 42a, 42b, 42c CCD 43a, 43b, 43c A / D converter 44 Shading correction circuit 45 Buffer memory 46 γ correction circuit 47 Black separation / RGB generation circuit 48 Gradation processing circuit 49 Selector 50a, 50b Buffer memory 51a, 51b Laser driver 52 LED driver 53 Development bias control circuit 54 Charging Voltage Control circuit 55 Laser light amount control circuit 56 Development bias control circuit 57 Motor control circuit 58 Main motor 59 Paper feed motor 60 Image separation circuit

Front page continuation (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display location H04N 1/036 A 8721-5C Z 8721-5C 1/23 103 C 9186-5C (72) Inventor Hidetoshi Kanai Tokyo Ricoh Co., Ltd. 1-3-3 Nakamagome, Ota-ku, Tokyo (72) Inventor Kenshi Yamakawa 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (72) Yoshio Kaneko Nakata, Ota-ku, Tokyo 1-3-6 Magome In Ricoh Co., Ltd. (72) Inventor Shinji Kobayashi 1-3-6 Nakamagome In Ota-ku, Tokyo In Ricoh Co., Ltd.

Claims (4)

[Claims] 1. Corresponding to a plurality of exposing means for exposing different positions on a photoconductor and each of the exposing means for visualizing each latent image formed on the photoconductor by the exposing means. In the image forming apparatus provided with a plurality of developing means provided, the exposing means is a laser exposing means for irradiating the photosensitive member with a laser beam of a semiconductor laser through a deflector and an optical system, and arranged in a line. An array-shaped exposure unit that irradiates the photosensitive member with dot light formed by a light-emitting body or an optical shutter, and image formation is performed line by line in the sub-scanning direction by the developing unit corresponding to these exposure units. A characteristic image forming apparatus. 2. An exposure means comprising means for reading an image of an original read by a reading means into a character portion and a pattern portion, and different image formation for each of the range determined as the character portion and the range determined as the pattern portion. The image forming apparatus according to claim 1, wherein 3. A plurality of exposure means, at least one of which is provided with a semiconductor laser, and which is a laser exposure means for irradiating a photoconductor with a laser beam from the semiconductor laser via a deflector and an optical system, and One of them is an array-shaped exposure unit that irradiates the photosensitive member with dot light formed by a light-emitting body or an optical shutter that is arranged in a line, and the range determined to be the pattern portion is defined by the laser exposure unit. 3. The image forming apparatus according to claim 2, wherein the array-shaped exposing unit exposes the area determined to be the character portion after the exposure. 4. The latent image forming position on the photoconductor for exposure in the range determined to be the character is located downstream of the latent image forming position by exposure in the range determined to be the pattern portion. The image forming apparatus according to claim 2.