JPS63271363A - Image forming device - Google Patents

Abstract

PURPOSE:To obtain a clear image within a short period without expanding the size of a device when a specification area for changing color is simple by arranging two developing devices, and forming an image on the outside of a range specified by a specifying means and an image in the range on a material to be transferred by impressing developing biases respectively to the 1st and 2nd developing devices. CONSTITUTION:A developing means is provided with the 1st developing device 121 for developing an image formed on an image carrier 10 with one color and the 2nd developing device 122 for developing the image with the other color. The specifying means for specifying a prescribed range for changing a color in an original is arranged, an image outside the range specified by the specifying means is formed on the material to be transferred with one color by impressing a developing bias to the 1st developing device 121 and an image in the range specified by the specifying means is formed on the material to be transferred with the other color by impressing a developing bias to the 2nd developing device 122. When a specification area for changing a color is simple, a clear image can be obtained within a short period without expanding the size of the device.

Description

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

(Prior Art) Conventionally, in the field of known color copying machines (functional color copying), the following method is common in order to make a certain specific area a different color.

That is, a case will be described in which the copying machine main body is equipped with developing devices for black and color (different colors).

In such a state, as a first step, the latent image in the printed color area is erased by an image erasing lamp or the like at a predetermined timing by the control unit using a signal obtained in advance from the operator's operation panel for the color printing color area. Performs a black-only copy (print copy only in black areas).

In the second step, the copy paper with only the black area printed is passed through the paper feed system again and switched to the color developer.The black latent image area is erased and only the specific color area is developed, contrary to the process of the first step. and overlap them (superimposed copy).

However, in the above-mentioned apparatus, since images are formed (copied) by the above-mentioned superimposition, the apparatus has many drawbacks, such as the complexity of the apparatus and the time it takes to obtain a desired copy. there were.

Further, due to overlapping, the contact position with the photoreceptor is shifted due to curling of the copy paper, etc., resulting in a shift in the overlapping.

Furthermore, even when simply printing a collection of lines perpendicular to the direction of copying in a different color, the above steps have to be carried out, which has the disadvantage that it takes a long time to obtain the desired copy. there were.

(Problems to be Solved by the Invention) As mentioned above, even when the specified area to change color is simple, the device is too complicated, it takes time to obtain the desired image, and the image may be misaligned. , which eliminates the drawback of not being able to obtain a clear image, and when the specified area to change color is simple, image formation that can obtain a clear image in a short time without increasing the size. The purpose is to provide equipment.

[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 image 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 image forming apparatus, the developing means includes a first developing device that develops an image formed on the image carrier in one color, and a first developer that develops the image formed on the image carrier in the other color. a second developing device for performing development, an instruction means for instructing a predetermined range in which the color of the document is to be changed; and an instruction means for instructing the first developing device to develop an image outside the range specified by the instruction means; By applying a bias, one color is formed on the transfer material, and an image within the range specified by the instruction means is formed in the other color by applying a developing bias to the second developing device. It is composed of a control means for forming the image on the transfer material.

(Function) This invention specifies a predetermined range in which the color of the document is to be changed, and applies a developing bias to the first developer to convert the image outside the specified range onto the transferred material in one color. By applying a developing bias to the second developing device, an image within the specified range is formed on the transfer material in the other color.

(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. Fixed scales 21 and 22 are provided at both ends of the document table 2 to serve as a reference for setting the document, and furthermore, a document cover 11 and a work table 12 which can be opened and closed are provided near the document table 2.

The original placed on the document table 2 is processed by an optical system consisting of an exposure lamp 4 and mirrors 5, 6, and 7 reciprocating along the lower surface of the document table 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 9. ,．． 92
．． 93 and guided to the photosensitive drum 10,
An image of the original is formed on the surface of the photosensitive 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 formed by non-contact type developing units 121 and 122 which respectively contain black or red toner (single-component developer) and are selectively operated as required.
A visible image is created by attaching toner to the surface.

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 16□ and 162, 163 to a pair of registration rollers 17, and guided by this pair of registration rollers 17 to a transfer section. It has become. Here, the paper feed cassettes 13□, 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.
132 and 133 are respectively cassette size detection switches 60. ．． The cassette size is detected by 602 and 603. 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
are discharged onto 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. After the transfer, the photosensitive drum 10 is returned to its initial state by removing residual toner on the surface with a cleaner 26 and erasing any afterimages with a static elimination lamp 27. Note that 29 is a cooling fan for preventing the temperature inside the main body 1 from rising.

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, on which display information stored in a memory (not shown) is switched and displayed in accordance with each mode. Around this display section are selection keys 31as, 31bs, 31c, 31ds for selecting the mode displayed on this display section 302.
31es31f, 31g, and 31h are provided.

Further, the operation panel 30 has an operation key 30 as for moving a spot light source indicating the erase position of the document, which will be described later.
30b, 30c, 30d, and a position designation key 308 for inputting the coordinate position indicated by the spot light source.

The display section 302 is shown in FIGS. 5(a) and 5(b) 1. : As shown in the figure, the status of the device, etc. is displayed in text, and as shown in the same figure (C), trimming, masking mode, image movement mode, edge erase mode, multiple copy mode, 2
The selection screen for copy mode, multicolor copy mode, multiple copy mode, and centering mode for multiple sheets of originals can be graphically displayed. The screen for selecting the number of copies, the setting screen for the number of copies, the copy magnification selection screen, and the 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, and these carriages 41. ．． 412 is a guide rail 42. ．． 422, and can freely move in parallel in the direction of arrow a. That is, the four-phase pulse motor 33 drives the pulley 43. An endless belt 45 is stretched between the pulley 43 and the idle pulley 44, and one end of a first carriage 411 that supports the mirror 5 is fixed to a midway portion of the belt 45. On the other hand, a second carriage 412 supporting mirror 6.7
The guide portion 46 includes two grooves spaced apart in the axial direction of the rail 422.
Two pulleys 47.47 are rotatably provided, and 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, one end of a first carriage 411 is fixed to a midway portion of the wire 48. 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 serve as movable pulleys, the second carriage 412 moves in the same direction as the first carriage 411 at 1/2 the speed. In addition, the first and second carriages 4
The moving direction of 11.412 is controlled by switching 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 41□ is first moved toward the second carriage 41□, and then the lamp 4 is turned on and the carriage 41□ is 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. 15 shows the structure of the developing units 121 and 122. That is, the developing units 121 and 122 are respectively developing sleeves 12a and 12d.

It is composed of stirring rollers 12b and 12e and blades 12c and 12f that frictionally charge developer (toner). The developing device 121 stores black toner, and the developing device 12□ stores red toner. The gap between the developing sleeves 12c, 12f and the photosensitive drum 10 is 200 μm.

The blades 12c and 12f have a switching circuit 7 which will be described later.
3, the developing bias voltage is selectively applied. For example, when the changeover switch 73a of the changeover circuit 73 is turned on, the blade 12 of the developing device 121
c is the power supply voltage from the power supply circuit 72 (developing bias voltage;
-500V) is applied and the changeover switch 73b of the changeover circuit 73 is turned on, the blade 12 of the developing device 122
The power supply voltage (developing bias voltage) from the power supply circuit 72 is applied to f.
is applied.

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 601.
, 602, 603, etc., and detects an input from an input device 75, and drives the various chargers, a high voltage transformer 76, each blade 12c in the developer 121, 122,
The above-mentioned copying operation is performed by controlling the power supply circuit 72 that applies a developing bias voltage to 12f, the static elimination lamp 27, the blade solenoid 26a of the cleaner 26, the heater 23a of the fixing roller pair 23, the exposure lamp 4, and the motor 33. At the same time, it also controls the spot light source 131, pulse motor 33, 135, etc. to instruct the color change portion of the document. Note that the spot light source 131 and pulse motor 135 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.
It is controlled by the main control section 71 via 2.

The power supply circuit 72 is connected to the blades 12c, 12 of the developing devices 121, 122 through a switching circuit 73.
When the changeover switch 73a in the changeover circuit 73 is on, a developing bias voltage is applied to the blade 12c of the developer 121, and when the changeover switch 73b in the changeover circuit 73 is on, the development bias voltage is applied to the blade 12c of the developer 121. blade 12f
A developing bias voltage is applied to.

Next, instructions for changing the color range of the original image will be explained.

8 and 9, the first carriage 411 is provided with a guide shaft 130 along the lamp 4 in the part where the light of the lamp 4 is blocked, and this guide shaft 130 is provided with a guide shaft 130 that is attached to the color change range of the original. Spot light source 13 as a means for instructing
1 is movably provided. This spot light source 13
1 comprises a light-emitting element 132, such as a light-emitting diode or a lamp, and a lens 133, which are provided opposite to the document table 2. It is designed to be irradiated as a spot light.

The spot light source 131 also has a timing belt (toothed belt) 134 disposed along the guide shaft 1301::
is connected to. 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 131 is moved in a direction perpendicular to the scanning direction of the first carriage 41. Further, a position sensor 138 consisting of a microswitch for detecting the initial position of the spot light source 131 is provided in the first carriage 411 located at the end of the guide shaft 130 on the pulse motor 135 side. For example, when the spot light source 131 is moved, first,
The spot light source 131 comes into contact with the position sensor 138 to detect the initial position.

Next, a method for specifying the color change range of a document using the spot light source 131 will be explained using FIGS. 10 to 12. When specifying the color change range of a document, the document G is set with the copy 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 41□ and the spot light source 131 are moved in the scanning direction (the direction of the arrow X 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 multicolor copy 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 spotlight to, for example, 81 points on the document G shown in FIG. In this state, press the position designation key 30e. Then, the X coordinate position (xl) specified by these 81 points is stored in the main control section 71 shown in FIG. In the same way, if you press the position designation key 30e with the spotlight moved to point S2 on document G, the position of the X coordinate designated by point 82 (
x2) is stored in the main control unit 71. The position of this spot light can be detected, for example, by counting the number of driving pulses of the pulse motor 33. This allows the first
As shown in Figure 1,

The original G, on which the color change range has been specified as described above, is reversed in the X direction shown in FIG. be done.

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 designation state (STI) shown in FIG. 5(c), the operator selects the multicolor copying (color change) mode by pressing the selection key 31b (ST2). Then, a selection screen for inverting the color change is displayed for the selection key 31a, as shown in FIG. 12(a), and a pattern of the document frame and the specified range (pattern frame) is displayed (Sr1). At this time, partial color display is performed by displaying only the basic color (black) portion.

Next, the operator turns over the document G on which the image shown in FIG. 13 is written and places it on the document table 2 (Sr1). Next, the operator presses the operation keys 30a to 30d.
and position designation key 30e to designate 80 points and 82 points as the color change range on the document G (Sr1
). Then, the color change range designated by the spot light source 131, that is, the position of the X coordinate, is stored in an internal memory (not shown) (Sr1).

In this state, when the copy key 30□ is turned on, the main controller 71 starts exposure scanning (Sr9),
Using the X coordinates (xl, X2) as a color change range stored in an internal memory (not shown),
．． Black printing and red printing are performed by switching control 122 (STIO).

That is, the developing point of the developing device 121 is located at the photosensitive drum 10.
The changeover switch 73a in the changeover circuit 73 is turned on by the main control unit 71 from the start point of the electrostatic latent image of the original image to the X1 coordinate and from the X1 coordinate to the end point. . As a result, the developing device 121
A developing bias voltage from the power supply circuit 72 is applied to the blade 12c. By this application, the black toner is triboelectrically charged by the blade 12c of the developing device 12□. Therefore, from the starting point on the photoreceptor drum 10,
A developing device 121 develops black toner on the electrostatic latent image between the coordinates and between the X and L coordinates and the end point.

Furthermore, until the developing point of the developing device 122 reaches the X, L coordinates of the electrostatic latent image of the original image on the photosensitive drum 10, the main control section 71 turns on the changeover switch 73b in the changeover circuit 73. It's turned on. As a result, a developing bias voltage from the power supply circuit 72 is applied to the blade 12f of the developing device 12□. By this application, the developing device 12
The black toner is triboelectrically charged by the second blade 12f. Therefore, red toner is developed by the developing device 122 on the electrostatic latent image on the photosensitive drum 10 between the X1 coordinate and the X-coordinate.

Therefore, on the surface of the photosensitive drum 10, the area other than the area surrounded by the spot light W of the document G is formed in black, and the area surrounded by the spot light W of the document G is formed in red. be done.

Thereafter, in synchronization with this operation, the paper P is supplied to the transfer section by the registration roller pair 17, and the image is transferred onto the paper P. Therefore, as shown in FIG. 14, on this paper P, an image is formed in black on the portion of the document G other than the area surrounded by the frame W (part A), and
An image is formed in red in the area within the area (portion B).

Then, the paper P is fixed by the fixing roller 21 and sent to the paper ejection tray 25 via the paper ejection roller 24 (STII
).

This allows images to be copied neatly without overlapping when changing colors.

Incidentally, the operation timing of the main parts during the above-mentioned development is as shown in FIG. Here, time t3 corresponds to the time it takes the photoreceptor drum 10 to move from the charging position to the exposure position, and time t corresponds to the time it takes the photoreceptor drum 10 to move from the exposure position to the development position by the developer 121. The time t2 corresponds to the time it takes for the photosensitive drum 10 to move from the developing position by the developing device 12□ to the developing position by the developing device 122.

Further, in response to the display in step 3 above, the operator selects inversion by pressing the selection key 31a (Sr
4). Then, the display unit 302 performs partial color display by displaying the inside of the pattern frame (Sr1), as shown in FIG. 3B. After this, step 6 above
By carrying out the operations in step 11, the red image and the black image can be clearly copied without overlapping.

As described above, two developing devices each having a one-component developer and performing development by frictional charging are prepared, and one of the developing devices is biased at a timing outside a pre-specified range, that is, a row gathering area. By applying voltage,
Developing with one color, stopping the application of a developing bias to the one developing device at the timing of the row gathering area,
By applying a developing bias voltage to the other developing device, development is performed in the other color, so if the designated area to change color is simple, it can be done quickly and clearly without increasing the size. You can get a good image.

Furthermore, if you try to realize the above device using a conventional developing device, that is, a developing device with two-component developer, even if you simply switch the developing bias, that is, raise the developing bias higher than usual, the photosensitive This is not possible because the product developed by the first-stage developer is scraped off by the second-stage developer due to contact with the body drum. For this reason, the above-mentioned device can be realized by using a non-contact developing device that sprays toner by using a potential difference with the photoreceptor drum.

Note that the color to be copied may be another color.

[Effects of the Invention] As detailed above, according to the present invention, when the designated area to change color is simple, a clear image can be obtained in a short time without increasing the size of the image. A forming device can be provided.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a flowchart for explaining the main parts of the operation, FIG. 2 is a perspective view of the external appearance of the image forming apparatus, and FIG. 3 is a side cross-sectional view of the image forming apparatus. Figure 4 is a plan view showing the configuration of the operation panel, Figure 5 is a diagram showing an example of the display section, Figure 6 is a perspective view schematically showing the drive mechanism of the optical system, and Figure 7 is the overall view. FIG. 8 is a perspective view of the main parts of the spot light source, FIG. 9 is a side sectional view of the main parts of the spot light source, and FIGS. 10 and 11 are the main parts of the spot light source. A plan view shown to explain the operation of specifying the color change range of the original used, 1st
Fig. 2 shows an example of the display on the display unit during partial color copying, Fig. 13 shows an example of a document on which partial color copying is performed, and Fig. 14 shows an example of a copy of paper on which partial color copying is performed. FIG. 15 is a sectional view showing the structure of the developing device, and FIG. 16 is a diagram for explaining the operation timing of the main parts during development. DESCRIPTION OF SYMBOLS 1...Main body, 2...Document stand, 10...Photosensitive drum, 121.122...Developer (first, second developer), 12c, 12f...Blade, 30... ...Operation panel, 302...Display section, 30a-30d...Operation keys, 30e...Position specification key, 31a-31h...
- Selection key, 33...Pulse motor, 71...Main control unit, 131...Spot light source, 135...Pulse motor, P...Paper, W...Frame. Applicant's agent Patent attorney Takehiko Suzue Figure 1 (C) (d) Figure 5 (e) (f) Figure 5 Figure 7 Figure 10 Figure 11 (a) (b) Figure 12 Figure 13 Figure 14

Claims (2)

[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 the image carrier, and a transfer means for transferring the developed image onto a transfer material, the developing means is provided with an image formed on the image carrier. A first developing device that develops the image formed on the image carrier with one color and a second developing device that develops the image formed on the image carrier with the other color are provided to change the color of the document. an instruction means for instructing a predetermined range; and an image outside the range specified by the instruction means is formed on the transfer material in one color by applying a developing bias to the first developing device; An image forming apparatus comprising: a control means for forming an image within a range specified by the means on a transfer material in the other color by applying a developing bias to the second developing device. Device. (2) The image forming apparatus according to claim 1, wherein the first and second developing devices are of a non-contact type using a one-component developer.