JPS63240565A - Image forming device - Google Patents

Abstract

PURPOSE:To bring a part of one original to an image formation by a gradation property being different from that of other part, by bringing an image of the outside of a range instructed by an instructing means or a image of the inside of its range, to photostatic elimination by using a static eliminating element, and changing the gradation property. CONSTITUTION:A prescribed range for changing a gradation property in an original G is instructed, and an image of the outside of its instructed range or an image of the inside of its range is brought to photostatic elimination by using a static eliminating element (erasion/partial gradation array) 150 from an image carrying body, by which the gradation property is changed by a changing means. Subsequently, an image G of the inside of the instructed range is formed on a material to be transferred (form) P by one gradation property by the changing means, and an image of the outside of this range is formed on the material to be transferred P by the other gradation property by the changing means. In such a way, a part of one original G can be brought to an image formation by the gradation property being different from that of other part, and with respect to the original G having the gradation property and a contrast, an easily visible and distinct image can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention (Field of Industrial Application) The present invention relates to an image forming apparatus applied to, for example, an electronic copying machine.

(Prior Art) As is well known, a copying machine has a function of copying an original image directly onto a sheet of paper, or enlarging or reducing the original image to make a copy. Recently, there has also been a method of copying by erasing images within a predetermined range of the original (masking), or a method of copying by erasing images outside of a predetermined range (cropping).
has been developed and put into practical use.

By the way, with such a device, part of the manuscript (partial)
It was not possible to change the gradation.

For this reason, the contrast of the entire document is low, and there is a problem in copying images when a portion of the document includes a photograph or the like. For example, in old newspapers, where the white background has yellowed and the contrast between the text and the white background is low, and there is a photograph in the text, in order to obtain a clear image with high contrast and no overlapping, A developing system with a high γ (gamma: slope of the characteristic curve of image density with respect to electrostatic image potential) value (low gradation) is used, and the exposure is set to be bright for copying. In this case, the part of the photo will be crushed.

In addition, in order to faithfully reproduce the photograph, a Genjo system with a low γ value (high II tonality 21!! Ideally, a γ value of 1.0 and a wide dynamic range is required) is used. It is necessary to make a copy.

Therefore, it is difficult to obtain clear images in both cases. This type of manuscript is not limited to the example above, but may also include printing on a color background. There are many, such as 5th grade.

(Problem to be solved by the invention) As mentioned above, a part of one manuscript has a different rl from other parts.
This eliminates the drawback that it is not possible to form an image with A tonality, and that it is not possible to form an easy-to-read and clear image on originals with gradation and contrast.
It is possible to form an image on a part of a document with a different gradation from that of other parts, and it is possible to form an image that is easy to see and clear on a document with gradation and contrast. The purpose is to provide a forming device.

[Structure of the Invention] (Means for Solving the Problems) The image forming apparatus of the present invention includes a scanning means for optically scanning a document placed on a document table, and an optical edge obtained by the scanning means. an optical system that forms an image on a charged image carrier, a developing device that develops the image formed on the image carrier, and a transfer device that transfers the developed image to a transfer material. In the above-mentioned document, an instruction means for instructing a predetermined range in which the gradation of the gradation of the original is to be changed, and an image outside the range specified by the instruction means, or an image inside the range, is photostatically neutralized using a static elimination element. By this,
A changing means for changing the gradation and an image inside the range specified by the instruction means are formed on the transfer material with one gradation by the changing means, and an image outside the range is formed on the transfer material with one of the gradations specified by the changing means. It is comprised of a control means for forming the image on the transfer material with the other gradation by the changing means.

(Function) This invention specifies a predetermined range in which the gradation of a document is to be changed, and removes an image outside the specified range or an image inside the specified range from the image carrier using a static eliminating element. By optically removing static electricity, the gradation is changed by the changing means, and the image inside the specified range is formed on the transfer material with one gradation by the changing means, and the image outside the above range is formed on the transferred material. The image is formed on the transfer material with the other gradation by the changing means.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIGS. 2 and 3 schematically show an image forming apparatus of the present invention, such as a copying machine. That is, 1 is a main body of a copying machine, and a document table (transparent glass) 2 is fixed to the upper surface of the main body 1 to support a document. At both ends of the document table 2 are fixed scales 2z and 22 that serve as standards for setting the original plate.
Further, near the document table 2, a document cover 11 and a work table 12, which can be opened and closed, are provided.

The original placed on the original platen 2 is moved back and forth by an optical system consisting of an exposure lamp 4 and mirrors 5, 6, and 7 along the lower surface of the original platen 2 in the direction of arrow a. It is designed to be exposed and scanned. In this case, mirror 6.7 moves at half the speed of mirror 5 so as to maintain the optical exposure length. The light reflected from the original by the scanning of the optical system, that is, the light reflected from the original by the light irradiation of the exposure lamp 4 is reflected by the mirror 5.6.7, passes through the variable magnification lens block 8, and further passes through the mirror 91. .92
．． The light is reflected by the photoreceptor drum 9i and guided to the photoreceptor drum (selenium drum) 10, so that an image of the document is formed on the surface of the photoreceptor drum 10.

The photosensitive drum 10 rotates in the direction of arrow C in the figure, and the surface is first charged by the charging device 11, and then the image is exposed to slit light to form an electrostatic latent image on the surface. This electrostatic latent image is made visible by adhering toner to it by a developing device 12 containing, for example, black toner.

On the other hand, the paper (transferring material) P is delivered from the selected upper paper feed cassette 131, middle paper feed cassette 132, or lower paper feed cassette 133 to the feed rollers 141, 142, 14.
3 and roller pairs 151, 152, and 153, and are guided through paper guide paths 16r and 162, 163 to a registration roller pair 17, and by this registration roller pair 17 are guided to a transfer section. ing. Here, the above paper feed cassette 131.132.13
3 is removably provided at the lower right end of the main body 1, and either one can be selected on the operation panel described later. Note that each of the paper feed cassettes 131.
The cassette sizes 132 and 133 are detected by cassette size detection switches 601, 602, and 603, respectively. This cassette size detection switch 6
01.602.603 is composed of a plurality of microswitches that are turned on and off according to the insertion of cassettes of different sizes.

The paper P sent to the transfer section comes into close contact with the surface of the photoreceptor drum 10 at the transfer charger 18, so that the toner image on the photoreceptor drum 10 is transferred by the action of the charger 18. . This transferred paper P is transferred to the peeling charger 1
The transferred image is electrostatically separated from the photoreceptor drum 10 by the action of step 9, is conveyed by a conveyor belt 20, and is sent to a fixing roller 21 as a fixing device provided at the end of the conveyor belt. It will be established. Then, paper P after fixing
The sheets are delivered to a tray 25 outside the main body 1 by a pair of delivery rollers 22, a sorting gate 23 operated as shown by the solid line, and a pair of paper discharge rollers 24. Further, after the photosensitive drum 10 has been transferred, residual toner on the surface is removed by a cleaner 26, and afterimages are erased by a static elimination lamp 27, so that the photosensitive drum 10 returns to its initial state. Note that 29 is a cooling fan for preventing the temperature inside the main body 1 from rising.

On the other hand, a multiple copying unit 28 is provided below the copying machine main body 1 to make it possible to copy both sides of a sheet of paper or to make multiple copies on the same side.

This unit 28 includes a gate 23 for the above-mentioned sorting, a pair of paper discharge rollers 24, and a gate 23 for the above-mentioned sorting.
a plurality of roller pairs 28b and 28C that guide the sheets taken in by the rollers to the stacking section 28a;

28d is provided. Further, the stacking section 28a is provided with a delivery roller 28e that sends out the paper temporarily stored in the stacking section 28a. This delivery roller 28e can move up and down as shown by the arrow in the figure, depending on the thickness (number of sheets) of the stored paper. The paper sent out by the delivery roller 28e is guided to the control gate 28g via a separation roller pair 28f that separates and sends out the paper sheets one by one.

When performing multiple copying, the control gate 28q is rotated in the direction of the arrow M shown in the figure to guide the paper to the registration roller pair 17 via the transport roller pair 28h and the paper guide path 28i. Further, when double-sided copying is to be performed, the state shown in the figure is used, and the paper is guided to the reversing section 28 via a pair of conveying rollers 28j. The paper is inverted at 28
When stored in the paper guide path 281, the control gate 280 is rotated in the direction of the arrow T shown in the figure, and guides the paper sent by the pair of transport rollers 28j to the pair of registration rollers 17 via the pair of transport rollers 28i1 and the paper guide path 281. It is done like this. still,
In this embodiment, the control gate 2El is always rotated in the direction of the arrow M shown in the figure, and only multiple copying is possible.

FIG. 4 shows the operation panel 30 provided on the main body 1. 301 is a copy key for instructing the start of copying; 302
is a display section consisting of, for example, a liquid crystal dot matrix display, and display information stored in a memory 140, which will be described later, is switched and displayed in accordance with each mode. Around this display section are selection keys 31a, 31b131c, 31d131e for selecting the mode displayed on this display section 302.
, 31f, 31Q, and 31h are provided.

Further, the operation panel 30 includes operation keys 30a and 30b for moving a spot light source indicating a document erasure position or a gradation change position, which will be described later.

30c, 30d, and a position designation key 308 for inputting the coordinate position indicated by the spot light source.

As shown in FIGS. 5(a) and 5(b), the display unit 302 displays the status of the device, etc. in text, and as shown in FIG. 5(C), trimming, masking mode, and image movement mode. , edge erase mode, multiple copy mode, two original copy mode, photo copy mode, multiple copy mode,
And the centering mode selection screen is graphically displayed, as shown in (d) to (Q) of the same figure, the edge mode selection screen for selecting one or two originals, the setting screen for the number of copies, and the selection for the copy magnification. The screen and copy status screen are displayed graphically.

FIG. 6 shows a drive mechanism for reciprocating the optical system. That is, the mirror 5 and the exposure lamp 4 are supported by a first carriage 411, and the mirror 6.7 is supported by a second carriage 412, respectively. It can be moved in parallel in any direction. That is, 4
Phase pulse motor 33 drives pulley 43. An endless belt 45 is connected between the pulley 43 and the idler pulley 44.
The mirror 5 is placed in the middle of this belt 45.
One end of the first carriage 411 that supports the is fixed. On the other hand, the second carriage 41 supporting the mirror 6.7
Two pulleys 47 and 47 are rotatably provided on the second guide portion 46 and spaced apart in the axial direction of the rail 422.
A wire 48 is stretched between these pulleys 47, 47. One end of this wire 48 is fixed to a fixed part 49, and the other end is fixed to the fixed part 49 via a coil spring 50. Further, a first wire is provided in the middle of the wire 48.
One end of the carriage 411 is fixed. Therefore, as the pulse motor 33 rotates, the belt 45
rotates, the first carriage 411 moves, and the second carriage 412 also moves accordingly. At this time, since the pulleys 47.47 act as movable pulleys, the first carriage 41! In contrast, the second carriage 422 moves in the same direction at 1/2 the speed. Note that the moving direction of the first and second carriages 411 and 412 is changed by changing the rotation direction of the pulse motor 33.

Further, the first carriage 411 is moved to a predetermined position (home position according to the magnification) by driving the motor 33 according to the paper size and magnification. Then, when the copy key 301 is pressed, the first
The carriage 411 is first moved toward the second carriage 412, and then the lamp 4 is turned on and moved away from the second carriage 412. When scanning of the original is completed, the lamp 4 is turned off and the first carriage 411
is returned to the home position.

FIG. 7 shows the overall control circuit.

The main control unit 71 includes an operation panel 30 and various switches and sensors, such as the cassette size detection switch 6Ch.
, 602, 603, etc., and detects the input from the input device 75, and drives the various chargers. The exposure lamp 4, motor 33, etc. are controlled to perform the copying operation of the previous book, and the spot light source 13 is
1, pulse motor 33.135, memory 140, erase/
It controls the partial gradation array 150, array drive unit 160, etc. to erase unnecessary parts of the original or change the gradation of a part of the original. Note that the spot light source 131, pulse motor 135, erasure/partial gradation array 150, array drive section 160, and memory 140 will be described later.

Further, the main control section 71 displays characters and patterns on the display section 302 for each mode in accordance with character information or pattern information stored in a memory (not shown). A quick disk or the like may be used as the memory.

The exposure lamp 4 is controlled by the main control section 71 via the lamp regulator 81, and the heater 23a is controlled by the heater control section 8.
The motor 33.13 is controlled by the main control unit 71 via the motor 33.
5 is controlled by the main control section 71 via a motor driver 78.

Next, the means for changing the gradation of the original image will be explained. 8 and 9, the first carriage 411 has a guide shaft 1 along the lamp 4 in the part where the light of the lamp 4 is blocked.
30, and this guide shaft 130 is provided with a spot light source 1 as a means for indicating the gradation change range of the original.
31 is movably provided. This spot light source 1
Reference numeral 31 includes a light emitting element 132, such as a light emitting diode or a lamp, and a lens 133, which are provided facing the document table 2. It is designed to be irradiated as a spot light.

Further, the spot light source 131 is connected to a timing belt (belt with m) 134 disposed along the guide shaft 130. This timing belt 134 is passed between a pulley 136 provided on the rotating shaft of a pulse motor 135 and a driven pulley 137. Therefore, by rotating the pulse motor 135, the spot light source 1
31 is moved in a direction perpendicular to the scanning direction of the first carriage 411. Further, a position sensor 138 consisting of a microswitch for detecting the initial position of the spot light source 131 is provided on the first carriage 41+ located at the end of the guide shaft 1.30 on the pulse motor 135 side. and,
For example, when the spot light source 131 is moved, the spot light source 131 first comes into contact with the position sensor 138 and its initial position is detected.

Next, a method for specifying the gradation changing means for an original using the spot light source 131 will be described with reference to FIGS. 10 to 12. When specifying the gradation change range of a document, the document G is set with the close-up side facing down on the fixed scale 21 side, as shown in FIG. In this state,
When the operation keys 30a to 30d are operated, the spot light source 131 is moved with the light emitting element 132 turned on.

That is, when the operation keys 30b and 30d are pressed, the motor 33 is driven, and the first carriage 411 and the spot light source 1 are driven.
31 is moved in the scanning direction (arrow y direction shown in FIG. 10). Further, when the operation key 30a130c is pressed, the motor 135 is driven, and the spot light source 131 is moved in a direction perpendicular to the scanning direction (in the direction of arrow X shown in FIG. 10).

When specifying the photocopy mode, the operator operates the operation keys 30a to 30d while visually observing the spot light that has passed through the document G, and moves the spot light to, for example, 81 points on the original liG shown in FIG. Press the position designation key 30e.

Then, the coordinate position specified by this Si point is stored in the main control section 71 shown in FIG. Similarly, 82 of manuscript G
When the position designation key 30e is pressed with the spotlight moved to a point, the positions of the 82 points are stored in the main control section 71. For example, the position of this spot light is set by a pulse motor 33.135.
This can be detected by counting the number of driving pulses. After this, as shown in Fig. 11, the area outside the frame W formed by the 81st and 82nd points is designated as the range for low gradation copying (character copying) (M subscale II) as one gradation. The area within the frame W (hatched area) is designated as the range for high gradation copying (photocopying) as the other gradation.

In this way, when the NWA change range is designated, the main controller 71 performs calculations based on the positions of the designated two points and the copy magnification, and the memory 140 stores the gradation change range. A high level signal @n 1 II is stored in the area, and a low level signal "0" is stored in the other areas. That is,
This memory 140 is composed of, for example, a RAM whose capacity in each column direction is approximately equal to the moving distance of the spot light source 131 in the X direction divided by the position resolution in the y force direction. As shown in FIG. 12, high level signals are stored in addresses corresponding to the shaded areas, and low level signals are stored in other addresses.

The original G, on which the gradation change range has been specified as described above, is reversed in the y direction shown in FIG. 10 and set on the fixed scale 21 side with the copy side facing down. The back side is photographed. Therefore, in this state, the original image and the partial gradation data stored in the memory 140 are associated with each other.

Furthermore, instructions for erasing range in the document image erasing means (trimming mode, masking mode, etc.) are made in the same manner as the above-mentioned instruction for gradation change range.

On the other hand, as shown in FIG.
l! Erasing/partial tone array 1 as illumination changing means
50 are provided in close proximity. This erase/partial til
As shown in FIGS. 14 and 15, the L array 150 includes a plurality of light-shielding cells 151 arranged in a direction perpendicular to the rotational direction of the photoreceptor drum 10, and a plurality of light-shielding cells 151 inside each of these light-shielding cells 151. A light emitting element 152 made of, for example, a light emitting diode as shown in FIGS. 16(a) and 16(b) is provided. Further, the light from the light emitting element 152 is transmitted to the opening of each cell 151 facing the photoreceptor drum 10.
A lens 153 is provided to condense light from the inside to the surface thereof. The number of light emitting elements arranged in this erase/partial gradation array 150 is matched with the capacity of the memory 140 in the column direction, for example. Here, if the width of each light emitting element 152 is P and the number m is N, the total length of the erasure/partial gradation array 150 is Q-NXP.

The erasure/partial tone array 150 is driven by the array driver 160 described above. This array drive unit 160
As shown in FIG. 17, the shift register 161 has the same number of bits as the number of bits in the column direction of the memory 140.
, a store register 162 that holds the contents of this shift register 161, and a plurality of switches whose switching is controlled by each output signal of this store register 162 and a switching signal (erasure signal, gradation change signal) from the main control unit 71. Element 1
The fixed contacts 163b:... of these switch circuits 163,... are grounded via a resistor RO, and the fixed contacts 163C1... are grounded. , movable contact piece 163a
are connected to respective cathodes of the light emitting elements 152 constituting the erasure/partial gradation array 150, respectively. The anode of each of these light emitting elements 152 is connected to the power supply VCC through a current limiting resistor R, respectively.

As a result, when the movable contact piece 163a is connected to the fixed contact 163b, the voltage v3 divided by the resistors R and RO is applied to the light emitting element 152, so that the light emitting cord 152 emits light m La It emits light. Further, when the movable contact piece 163a is connected to the fixed contact 163C, the light emitting element 152 has a voltage VE divided only by the resistor R.
By applying R, the light emitting cord 152 increases the light amount LE.
Lights up in R. In addition, the movable contact piece 163a is connected to the fixed contact 16
3b and 163C (R is released), the light emitting element 152 is off.

Note that the light It L s of the light emitting element 152 is
The value of the voltage Vs is selected by the resistor RO so that it is between 90% and 50% of ER.

After specifying the erasure range or gradation change range of the original as described above, when the original cover 11 is closed and the copy key 301 is pressed, the first carriage 411 and the photosensitive drum 10 are operated. , the memory 14
Data for one column is sequentially read out from 0 in the row direction (as shown in FIG. 12). This read data D1 is transferred to the shift register 161 of the array driving section 160 in response to the clock signal CLK. After one column of data has been transferred to the shift register 161, when the charged portion of the photoreceptor drum 10 reaches the erase/partial gradation array 150, the main controller 71 outputs a latch signal LTH, and this signal The data stored in the shift register 161 is supplied to the store register 162 in accordance with the data stored in the shift register 161. That is, the position of charge removal (surface potential change) by the erase/partial gradation array 150 is the charger 11.
and the exposure section Ph, the memory 14
For example, in one column of data output by 0, the angle between the erasure/partial gradation array 150 and the exposure part ph is θ1,
Assuming that the photosensitive drum 1o is rotating at an angular velocity ω,
The output timing of the latch signal LTH is controlled so that it is supplied to the store register 162 before θ1/ω.

Each switch element 163 of the switch circuit 164 is controlled by the output signal of the store register 162 and a switching signal from the main control section 71.

In other words, the N tonality change signal is being supplied as the switching signal from the main control section 71! g (photocopying mode), when the output level of the store register 162 is high, the movable contact piece 163a is connected to the fixed contact 163b, and when it is low level, the movable contact piece 163a is opened. As a result, the light emitting element 152 connected to each switch element 163 has a switch element 163 connected to the movable contact piece 16.
3a is connected to the fixed contact 163b, the light m
It is turned on at Vs, and turned off when the movable contact piece 163a is open. Therefore, among the charged parts of the photoreceptor drum 10, the part where the light emitting element 152 is turned on is slightly charged, and the surface potential is lowered, and the part whose surface potential has been lowered is exposed to light after subsequent exposure. As a result, an electrostatic layer acid with a low potential step is formed, and the gradation of the original image is changed. Thereafter, in the same manner, the memory 14
Data of 0 is read out one column at a time, and a slight charge is removed.

In addition, an erase signal is supplied as a switching signal from the main control unit 71! g (trimming mode, masking mode), when the output level of the store register 162 is high level, the movable contact piece 163a is connected to the fixed contact 1.
When connected to 63C and at low level, movable contact piece 1
63a is opened. As a result, each switch element 163
The light emitting element 152 connected to can be the switch element 163! When the ll contact piece 163a is connected to the fixed contact 163C, it is lit with the light ff1VER, and the movable contact piece 163a
It will be turned off if it is open. Therefore, among the charged portions of the photoreceptor drum 10, the portion where the light emitting element 152 is turned on is completely neutralized, and even if this portion is subsequently exposed, a static 'R latent image is not formed, and the original image is This means that deletion has occurred. Below, in the same way, memory 1
40 data are read out one column at a time, and the image is erased.

The amount by which the surface potential on the photoreceptor drum 10 is slightly removed by the erasure/partial gradation array 150 is 5 to 5 of the image exposure amount.
It is approximately 0%. This prevents the toner density within the partial gradation area from decreasing.

Next, the copying operation of the present invention in the above configuration will be explained with reference to the flowchart shown in FIG. For example, in the mode specification state (ST1) shown in FIG. 5(C), the operator
11 change) mode is selected by pressing the selection key 31b (ST2). Then, as shown in FIG. 18(a), a selection screen for reversing gradation change is displayed for the selection key 31a, and a pattern of the original frame and the specified range (pattern frame) is displayed (ST3). . At this time,
Partial high gradation display is performed by displaying only the basic gradation (low LLI) portion.

Next, the operator turns over the document G on which the image shown in FIG. 19 is written and places it on the document table 2 (ST6). Next, the operator presses the operation keys 30a to 30d.
and position designation key 30e to select the WI on the document G.
Specify the S1 point and the 82nd point as the key change range (S
T7). Then, the control unit 71 performs calculations based on the positions of the grape circumference frame W designated by the spot light source 131, that is, the 81st point and the 82nd point, and the memory 14
As shown in FIG. 12, a high level signal is stored in the address corresponding to the inside of the frame W formed by the spot light source 131 as partial gradation data of the photo (high fi 11) portion at 0, and the frame W formed by the spot light source 131 is A low level signal is stored at an address corresponding to the outside of the (ST8).

In this state, when the copy key 301 is turned on, a copying operation of the original G is performed using the developing device 12, the erasure/partial gradation array 150, and the like.

That is, the surface of the photosensitive drum 10 is uniformly charged to a positive polarity by the charging device 11 (ST9).

Then, the array driver 160 receives the 12th data from the memory 140.
Partial gradation data of the photograph (j% gradation ll) portion shown in the figure is supplied, and the erasing/partial gradation array 150 is operated according to this partial gradation data, so that the charges inside the frame W are exposed to light. Static charge is slightly removed from above the body drum 10 (ST10)
.

Thereafter, exposure scanning and development are performed on the original G (ST11).

As a result, an image with high gradation and good photographic reproducibility is formed on the surface of the photoreceptor drum 10 in the part of the document G surrounded by the frame W, and in the area other than the area surrounded by the frame W. An image with low gradation and high contrast is formed.

When the image on the photosensitive drum 10 is transferred, the paper P has a frame W in the original IG, as shown in FIG.
Only the area outside the range surrounded by is copied in partial gradation,
The other portions are copied in the basic gradation (ST12).

Therefore, on this paper P, an image is formed with a low gradation in the part of the document G other than the area surrounded by the frame W, and an image is formed with a high gradation in the part surrounded by the frame W. Ru. Then, the paper P passes through the paper ejection roller 24 to the paper ejection tray 25.
(ST13).

As a result, high-gradation photographic images have gradation, and low-gradation character images have high contrast, making it easy to see and making clear copies. Furthermore, when the gradation is changed, images are not overlapped and are clearly copied.

Further, in response to the display in step 3 above, the operator selects inversion by pressing the selection key 31a (ST
4). Then, as shown in FIG. 18(b), the display unit 302 performs partial gradation display by displaying the inside of the pattern frame (ST5). After that, by carrying out the operations from step 6 to step 13 above, the high gradation photographic image has gradation, the uniformity of the low gradation text has high contrast, and easy-to-read and clear copies are made. can be done. The above table inversion selection may be performed after specifying the gradation change range.

Further, in the trimming mode, when erasing a predetermined range of images, the same operation as described above is performed. However, the image is erased by completely charging a predetermined range of charges from the photosensitive drum 10 by the erasing/partial gradation array 150.

As mentioned above, when changing the gradation of a part of a photograph, etc., in other words, when copying a predetermined part of one document with a different gradation (high gradation), before exposure is performed. ,
By slightly lowering the surface potential on the photoreceptor drum by irradiating the photoreceptor drum with light, we are able to slightly remove static electricity (partially change the development characteristics) only within the indicated range and copy. , high gradation photographic images have gradation, and low l@ tone character images have high contrast, making it easy to see and making clear copies. Furthermore, since high gradation portions and low gradation portions can be copied in a single copying process, the copying process can be simplified.

Also, 1! from the photoreceptor drum! A single charge eliminating element can be used to erase images of different layers and change gradation, and the structure can be simplified.

In the above embodiments, the case where the gradation is changed at one location has been described, but the present invention is not limited to this, and the same method can be applied even when the gradation is changed at a plurality of locations.

Furthermore, although a case has been described in which a light emitting diode is used as the gradation changing means, the present invention is not limited to this, and a fluorescent lamp or a combination of a cold shadow discharge tube and a liquid crystal array may be used. Furthermore, although we have explained the case of changing and erasing gradation separately, if you change them at the same time,
In other words, a mode may be provided in which the gradation is changed in a certain range and erased in another certain range.

In addition, we have explained the case where the erasing/partial gradation array is provided at a position corresponding to between the charging charger and the @exposure position, but (!! It may be provided at a certain position.

Further, although the case has been described in which erasing and changing of gradation are performed by one static eliminating element, the present invention is not limited to this, and the erasing and changing of gradation may be performed by separate defrosting elements.

[Effects of the Invention] As detailed above, according to the present invention, it is possible to form an image on a part of a document with a different gradation from other parts, and to create an original with gradation and contrast. In contrast, it is possible to provide an image forming apparatus that can form an image that is easy to see and clear.

4.Drawings (7) rfJ tl SuFa The drawings show one embodiment of the present invention, and FIG. 1 is a flowchart for explaining the photocopying operation, and FIG. 2 is a flowchart for explaining the photocopying operation.
FIG. 3 is a side sectional view of the image forming apparatus, FIG. 4 is a plan view showing the configuration of the operation panel, FIG. 5 is a diagram showing an example of the display on the display, and FIG. 6 is the optical system. FIG. 7 is a configuration diagram showing the overall 111111 circuit, FIG. 8 is a perspective view of the main parts showing the spot light source,
FIG. 9 is a side sectional view of the main part showing the spot light source, and FIGS. FIG. 12 is a diagram shown to explain the contents of the memory, FIG. 13 is a side sectional view of the main part showing the arrangement of the partial gradation array,
14 and 15 show the relationship between the partial gradation array and the photosensitive drum, respectively. FIG. 14 is a perspective view showing only the main part, FIG. 15 is a front view showing only the main part, and FIG. 16
The figure shows the configuration of the partial gradation array, and the figure (a
) is a side sectional view, FIG. 17 is a partially cutaway front view, FIG.
The figure shows an example of the display on the display during partial tone close-up photography.
FIG. 19 is a diagram showing an example of a document to which partial gradation copying is performed;
Figure 20 shows partial floor 1]1? ! FIG. 3 is a diagram illustrating an example of a copy of a sheet on which copying has been performed.

DESCRIPTION OF SYMBOLS 1...Main body, 2...Document stand, 10...Photosensitive drum, 12...Phenomenon, 30...Operation panel, 302
...Display section, 30a-30d...Operation key, 30e
...Position designation key, 31a-31h...Selection key,
33... Pulse motor, 71... Main control unit, 131
... Spot light source, 135 ... Pulse motor, 14
0...Memory, 150...Erase/partial tone array (
static eliminator), 160...array drive unit, P...paper, ph...exposure unit, W...frame.

Applicant's agent: Patent attorney Takehiko Suzue Figure 1 04 Figure (a) (b) (c) (C1) Figure 5 (e) (f) Figure 5 Figure 9 15th prisoner Figure 16 @Figure 17 (a) (b) Figure 18 Foil figure 19 Figure 20

Claims (4)

[Claims] (1) A scanning device that optically scans a document placed on a document table; an optical system that forms an optical image obtained by the scanning device onto a charged image carrier; and the image carrier. In an image forming apparatus comprising a developing means for developing an image formed on a body and a transfer means for transferring the developed image onto a transfer material, an instruction for specifying a predetermined range in which the gradation of the original is to be changed. means, a changing means for changing the gradation of an image outside the range indicated by the indicating means or an image inside the range using a charge eliminating element; An image inside the designated range is formed on the transfer material with one gradation by the changing means, and an image outside the range is formed on the transfer material with the other gradation by the changing means. An image forming apparatus comprising: a control means for controlling the image forming apparatus; (2) The image forming apparatus according to claim 1, wherein the instruction means is provided in the scanning means. (3) The image forming apparatus according to claim 1, wherein the static eliminating element is constituted by a line array of light emitting elements. (4) The image forming apparatus according to claim 1, wherein the static eliminating element is provided in front of the developing means.