JPH01293363A - Image forming device - Google Patents

Abstract

PURPOSE:To obtain the optimum copying image of a complex original in a single electrostatic process by operating a digital scanning unit and a scanning unit simultaneously for exposure scan. CONSTITUTION:When the title device is set in a first or a second photographic original copying mode with a photographic mode setting means, the digital scanning unit and the scanning unit are operated simultaneously for the exposure scan by a controller 12 functioning as an exposure control means, a mode setting control means, and a process control means. In the first mode, the entire surface of a photosensitive drum 9 is scanned and exposed to a beam based on a prescribed digital signal in parallel with the scanning of an original by the scanning unit, while the photographing area alone of the photosensitive drum 9 is scanned and exposed in the second mode. As a result, the copying image of an entirely photographic original or the complex original consisting of characters and photographs can be obtained by performing a single electrostatic photographing process.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an image forming apparatus capable of copying a photographic original, and more particularly to an image forming apparatus capable of copying a composite original image consisting of a photographic original and a text original. It is.

[Conventional technology]

2. Description of the Related Art Conventionally, image forming apparatuses have been put into practical use that can output a copy image of a document onto plain paper or designated paper using an electrophotographic process.

When copying an original using this type of device, the image quality of the original to be copied is generally such that, in the case of original images and character images, even the thin characters are clear, and the quality is high enough that developer does not adhere to the white area of the original. Various density controls are performed so that images can be formed.

FIG. 6 is a characteristic diagram showing the relative relationship between the original density and the copy density, where the vertical axis shows the copy image density D2, and the horizontal axis shows the original density DI.

In this figure, ■ is a relative density characteristic, where the original density D1 is d and the slope changes to γ.

As can be seen from this figure, the slope γ of the relative density characteristic I is corrected by lowering the surface potential of the photoreceptor after −order charging so that the original density DI is d and the slope changes to γ. JP-A-55-18656, JP-A-55-186
As shown in Japanese Patent Application No. 59, the AC bias applied during jumping development may be lowered or the AC bias applied during jumping development may be reduced.
By lowering the bias frequency, the slope γ of the relative concentration characteristic ■ was corrected.

However, when the original contains halftones, such as a photographic original, it has been proven that it is more desirable to have a linear relative density characteristic II, as shown in FIG.

Therefore, in order to obtain high-quality images of both text and photographs, the following methods (1) and (2) have conventionally been used.

(1) Various conditions such as charging conditions, exposure conditions, and development conditions of the photoreceptor are switched between text original image copying processing and photographic original image copying processing, that is, relative density characteristics during text original image copying processing. The charging conditions of the photoreceptor to match I,
Set various conditions such as exposure conditions and development conditions, and set various conditions such as f-electricity conditions, exposure conditions, and development conditions of the photoreceptor so as to match the relative density characteristics II when copying the photo original image.
Obtain a photocopy image.

(2) For example, once a mesh-like screen tone is exposed, the surface potential of the photosensitive drum is shown in FIG. 8! From a primary charging state with charging characteristic m, it is charged in a mesh pattern as shown in charging characteristic IV shown in FIG. 9, and in this state, the photographic original is exposed and scanned to obtain a photocopy image.

(Problem to be Solved by the Invention) In the case of a composite document in which text and photographs are mixed in the document image, when attempting to obtain a copy image using method (1) above,
The transfer process must be repeated twice, first exposing, developing, and transferring the text image area, and then exposing, developing, and transferring only the photographic image area again.

Also, if you try to obtain a copy image using method (2) above, -
In this method, a mesh-like screen tone is once exposed to light, the surface potential on the photosensitive drum is charged in a mesh pattern as shown in FIG. 9, and the photo original is exposed again.
The exposure process must be repeated twice.

As described above, when copying a composite document using a conventional image forming apparatus, the exposure process or transfer process is required multiple times, which causes problems such as a significant decrease in image forming efficiency. there were.

In addition, although the above method (1) makes it possible to obtain a delicate copy image, it has the disadvantage that it is difficult to remove the fog on the white background. When using the halftone method, if the color dots on the original and the white dots on the latent image happen to be in the same position, the copied image will be blank and the image will be rough (the halftone dot spacing is A state in which the area spreads and the white area expands). Therefore, 1 of the prior art
Using only this method has the problem of significantly narrowing the range of image formation that can be done in response to the recent advances in speed and image quality.

This invention was made in order to solve the above-mentioned problems, and by performing spot exposure on the photographic original area in parallel with the scanning exposure of the original, an optimal copy image of a composite original can be obtained with a single electrostatic process. It is an object of the present invention to provide an image forming apparatus that can obtain appropriate copy images for various originals.

[Means to solve the problem]

The image forming apparatus according to the present invention includes a digital scanning unit that scans and exposes a photoreceptor to an arbitrary position with a light beam based on a predetermined digital signal in parallel with the scanning of the original by the scanning unit, and a first . a photo mode setting means for setting a second photo original copy mode; and a first photo document copying mode set by the photo mode setting means. Alternatively, the apparatus is provided with an exposure control means for controlling parallel exposure scanning of the photoreceptor by the digital scanning unit and the scanning unit based on the second photo original copying mode.

Further, an area setting means for setting a photo area of the document image;
A mode setting control means may be provided for preferentially setting the second photo original copying mode based on the photographic area setting state by the area setting means.

Furthermore, the first . The second photographic original copying mode and this first. mode selection means for selectively selecting an arbitrary photo mode from a plurality of photo original copy modes different from the second photo original copy mode; A process control means for controlling image processing conditions may be provided.

(Function) In the present invention, when the first photo original copying mode is set by the photo mode setting means, the exposure control means:
The digital scanning unit and the scanning unit are simultaneously exposed and scanned, and a light beam based on a predetermined digital signal is exposed and scanned over the entire surface of the photoreceptor in parallel with the scanning of the document by the scanning unit.

On the other hand, when the second photo original copying mode is set by the photo mode setting means, the exposure control means causes the digital scanning unit and the scanning unit to perform exposure scanning simultaneously, and outputs a predetermined digital signal in parallel with the scanning of the original by the scanning unit. A light beam based on the photoreceptor is scanned for exposure over a photographic area of the photoreceptor.

Further, at this time, when a photographic area is set by the area setting means, the mode setting control means preferentially sets the second photographic original copying mode.

Further, the mode selection means selects the first and second modes for the original.
When an arbitrary photo mode is selected as an alternative from the photo original copying mode and a plurality of photo original copying modes different from the first and second photo original copying modes, the process control means The image processing conditions for the photoreceptor are controlled based on the photographic mode, and a photographic image conforming to the analog photographic mode or the digital photographic mode is formed.

〔Example〕

FIG. 1 is a cross-sectional view of an image forming apparatus showing an embodiment of the present invention. Reference numeral 1 denotes an original pressure plate, and an original (not shown) placed on an original table glass 3 (a photographic original) is shown.

Press 2 (composite original consisting of photos and text). Note that the surface of the document pressure plate 1 that comes into contact with the document table glass 3 is white.

Reference numeral 4 denotes an original illumination lamp (lamp) composed of, for example, a halogen lamp, and the reflected light of the original 2 illuminated by this lamp 4 is scanned via mirrors 58 to 5C. Incidentally, the lamp 4 and the mirror 5a together constitute a scanning unit, and are reciprocated for scanning by driving a motor (not shown) in the horizontal direction at a predetermined speed according to a set magnification.

Reference numeral 6 denotes an optical lens, which is positioned before image formation at a position where the reflected image scanned via the mirrors 5b and 5c is formed on the photosensitive drum 9 at a predetermined magnification. An optical image passing through the optical lens 6 is formed on a photosensitive drum 9 rotating at a constant speed via mirrors 5d to 5f. Above lamp 4. Mirror 5a
~5f, the optical lens 6, etc. constitute a first optical system.

7 is a laser light source section, which includes a semiconductor laser, a polygon mirror,
A laser beam is emitted based on the exposure data output from the controller 12, which is composed of an imaging lens, a scanner motor, etc. and also serves as the exposure control means and mode setting control means of the present invention, and passes through the folding mirror 8 to the photosensitive drum 9.
The entire surface or the main part of the photosensitive drum 9 is exposed and scanned in a spot-like manner, and the surface potential of the photosensitive drum 9 is charged in a mesh pattern as shown in FIG. Note that the laser light source section 7. The folding mirror 8 constitutes a digital scanning unit of the present invention, and based on exposure data output from the controller 12, a laser beam is scanned and exposed to an arbitrary position on the photosensitive drum 9 in parallel with the document scanning by the scanning unit. It is configured so that it can be

Reference numeral 10 denotes a static elimination lamp that eliminates residual charges on the photosensitive drum 9 in preparation for the image forming process. A primary charger 11 charges the photosensitive drum 9 uniformly.

A first developing unit 13 stores, for example, a red developer and develops the electrostatic latent image formed on the photosensitive drum 9 in red. A second developing unit 14 stores, for example, a black developer and develops the electrostatic latent image formed on the photosensitive drum 9 into black.

Note that the first developing unit 13 and the second developing unit 1
4, according to the development control signal from the controller 12,
One of the developing units is placed close to the photosensitive drum 9, and the other developing unit is retracted from the photosensitive drum 9.

Reference numeral 15 denotes a transfer charger, which transports the toner image developed on the photosensitive drum 9 via a transport guide 20, stops at the registration roller position, and synchronizes with the leading edge of the image formed on the photosensitive drum 9. After that, the image is transferred onto the recording paper 21 which is fed again.

Further, when the first photo original copying mode is set by the photo mode setting means to be described later, the controller 1 which also serves as exposure control means, mode setting control means, and process control means
2 causes the digital scanning unit and the scanning unit to perform exposure scanning at the same time, and exposes and scans the entire surface of the photosensitive drum 9 with a light beam based on a predetermined digital signal in parallel with the document scanning by the scanning unit.

On the other hand, when the second photo original copying mode is set by the photo mode setting means, the controller 12 causes the digital scanning unit and the scanning unit to perform exposure scanning at the same time, and outputs a predetermined digital signal in parallel with the scanning of the original by the scanning unit. The photographic area of the photosensitive drum 9 is exposed and scanned with the light beam based on the photosensitive drum 9. Further, at this time, if a photographic area is set by the area setting means to be described later, the mode setting control means preferentially sets the second photographic original copying mode.

Furthermore, the mode selection means to be described later selects the first mode for the document. The second photographic original copying mode and this first. When an arbitrary photo mode is alternatively selected from a plurality of photo original copying modes different from the second photo original copying mode, the controller 12 performs image processing on the photoreceptor based on the selected arbitrary photo mode. Conditions (f for photosensitive drum 9
image processing conditions such as electrical conditions, exposure conditions, development conditions, or screen tone exposure) to form a photographic image conforming to analog photography mode or digital photography mode. 16 is a separation charger.

A cleaner 17 collects toner remaining on the photosensitive drum 9. A conveyance belt 18 conveys the recording paper 21 after the transfer process to a position where a fixing device 19 is provided. The fixing device 19 applies pressure to the toner image transferred to the recording paper 21 using a heat roller and a pressure roller, and fixes the toner image onto the recording paper 21 by heat.

FIG. 2 is a plan view illustrating an example of the operation panel of the image forming apparatus shown in FIG.
2 is a display unit that displays copy modes such as copy mode and magnification. 33 is part of the numeric keypad, with X corresponding to the photo area,
Input numerical values such as Y coordinate value 1 magnification 1 number of sheets etc. 34 is a standard photo copy mode key which becomes the second photo original copy mode;
When this standard photocopying mode key 34 is pressed, the controller 12 controls the number key part 3 serving as an area setting means.
The photo original copy mode for the designated photo area from 3 is prioritized as the second photo original copy mode. 3
5 is a copy key, and when this copy key 35 is pressed, a copy operation is started.

36 is an opaque protective cover that covers mode switches 37 to 3.
9 (which also serves as photo mode selection means) is protected from being pressed all the time, and is configured to be opened and closed as necessary.

Note that the mode switch 37 is pressed to set the first photo original copying mode, and when this mode switch 37 is pressed, the controller 12 moves the original platen glass in parallel with the original exposure scanning by the scanning unit. This is a mode in which exposure data from the laser light source section 7 is outputted so that the entire surface of the photo original placed on the photo original is spot-exposed with a laser beam from the digital scanning unit (digital photo mode for the photo original).

Further, the standard photo copy mode key 34 is pressed to set the second photo original copy mode, and when the standard photo copy mode key 34 is pressed, the controller 12 operates in parallel with the original exposure scan by the scanning unit. , a mode in which the exposure data of the laser light source section 7 is outputted so that the laser beam is spot-exposed from the digital scanning unit only to the main part of the photographic original placed on the original platen glass 3 (the designated photographic area). (digital photo mode in composite original).

Further, the mode switch 38 is pressed to set the third photographic original copying mode, and when this mode switch 38 is pressed, the controller 12 controls the photosensitive drum when the scanning unit executes original exposure scanning. 9 charging conditions and exposure conditions.

This is a mode in which various conditions such as development conditions are set to linear relative density characteristics II (analog photographic mode for photographic originals).

Further, the mode switch 39 is pressed to set the fourth photographic original copying mode, and when this mode switch 38 is pressed, the scanning unit executes a plurality of original exposure scans, that is, the charging condition of the photosensitive drum 9 is set. This is a mode in which multiple copies are executed while changing various conditions such as exposure conditions and development conditions (analog photo mode for composite originals).

Next, the operation shown in FIG. 1 will be explained.

During normal character image copying, the reflection of the original 2 placed on the original platen glass 3 is reflected on the photosensitive drum 9 charged by the negative charger 11 according to the exposure scan of the scanning unit (first optical system). After the image is formed and developed by the first developing unit 13 or the second developing unit 14 designated by the operation unit main body 31, the developed toner image is transferred to the recording paper 21 by the transfer charger 15. Ru. And the fuser 19
The image is fixed and the paper is ejected.

On the other hand, when the mode switch 38 is pressed, the third photo original copying mode is set, and the charging conditions for the primary charger 11 are adjusted by the controller 12, and the density conditions match the linear relative density characteristic II. Set to . Thereafter, the photographic image is copied onto the recording paper 21 using the same electrostatic process as for text originals.

Further, when the mode switch 37 is pressed, the controller 12 sets the first photo original copy mode. Then, the controller 12 controls the document 2 placed on the document table glass 3 in parallel with the document exposure scan performed by the scanning unit.
Exposure data from the laser light source section 7 is outputted so that the entire surface of the (photographic original) is spot-exposed with a laser beam from the laser light source section 7, which serves as a digital scanning unit. In response, an electrostatic latent image corresponding to the spot latent image and the reflected image of the document is formed on the photosensitive drum 9. Thereafter, the photographic image is copied onto the recording paper 21 by the electrostatic process described above.

On the other hand, if the standard photocopy mode key 34 is pressed,
Controller 12 sets a second photo original copy mode. Then, in parallel with the exposure scanning of the original by the scanning unit, the controller 12 scans the photographic area designated by the operation unit main body 31, for example, an original 41 as shown in FIG. The exposure data of the laser light source section 7 is outputted so as to perform spot exposure with a laser beam from the laser light source section 7 serving as a digital scanning unit only at a position corresponding to the photographic original 44, 45 (consisting of). In response, an electrostatic latent image corresponding to the spot latent image and the reflected image of the document is formed on the photosensitive drum 9. Thereafter, the photographic image is copied onto the recording paper 21 by the electrostatic process described above.

This makes it possible to clearly output a copy image of a composite original with a single electrostatic process.

Note that in the above embodiment, the laser light source section 7. Although the folding mirror 8 constitutes the digital scanning unit of the present invention, the combination of the light converging lens and the light emitting diode constitutes the digital scanning unit, and the controller 12 controls the lighting of the light emitting diode in parallel with the original exposure scanning. The same effect can be obtained.

Further, it is not necessary that the imaging position of the reflected light from the scanning unit on the photosensitive drum 9 and the irradiation position of the laser beam irradiated from the laser light source section 7 on the photosensitive drum 9 completely match; Second developing unit 13.
It can be placed at any position before the 14 developing position. However, in that case, the controller 12 is configured so that the scanning unit or laser light source unit 7 that satisfies the positional relationship for light exposure and the laser light source unit 7 or scanning unit that performs post-exposure each expose the photosensitive drum 9 with a predetermined time difference. Control the timing.

FIG. 4 is a flowchart illustrating an example of the photo mode setting processing procedure according to the present invention. In addition, (1) to (1
4) shows each step.

First, the controller 12 determines whether a photo mode key for setting a photo mode is pressed.1)
If No, the normal image sequence is executed 2), and the process ends.

On the other hand, if the determination in step (1) is YES, it is determined whether the pressed photo mode key is the standard photo copy mode key 34 or not.3) YES? j mule controller 1
2 sets the second photographic original copying mode (4), and the controller 12, in parallel with the original exposure scanning by the scanning unit, selects the photographic area designated by the operation unit main body 31, for example, as shown in FIG. A manuscript 41 (text manuscript 42.
43 and photo manuscript 44. 45) photo manuscript 44
．． A copying sequence of the standard photocopy mode (composite photo mode) is executed in which the exposure data of the laser light source section 7 is outputted only at the position corresponding to 45 to perform spot exposure with a laser beam from the laser light source section 7 serving as a digital scanning unit. 5) and end the process.

On the other hand, if the determination in step (3) is NO, it is determined whether the mode switch 37 has been pressed 6), and YES.
If S, set the first photo original copy mode (7)
. Then, in parallel with the original exposure scanning by the scanning unit, the controller 12 performs spot exposure with a laser beam from the laser light source section 7 serving as a digital scanning unit onto the entire surface of the original 2 (photo original) placed on the original platen glass 3. The exposure data of the laser light source unit 7 is outputted so that the exposure data of the laser light source section 7 is In response, an electrostatic latent image corresponding to the spot latent image and the reflected image of the document is formed on the photosensitive drum 9. Thereafter, a copying sequence based on the digital photo mode is executed to copy the photographic image onto the recording paper 21 using the electrostatic process described above (8), and the process is completed.

On the other hand, if the determination in step (6) is NO, it is determined whether the mode switch 38 has been pressed (9), and Y
In the case of ES, the controller 12 sets the third photographic original copying mode (lO), and when executing original exposure scanning by the scanning unit, the charging conditions of the photosensitive drum 9, the exposure conditions,
Conditions such as development conditions are set to the linear relative density characteristic II, and a copying sequence based on the analog photographic mode is executed for the photographic original (11), and the process is completed.

On the other hand, if the determination in step (9) is NO, it is determined whether the mode switch 39 has been pressed 12);
If NO, the process returns to step (1), and if YES, the controller 12 sets the fourth photo original copy mode (1).
3). Next, a copying sequence is executed based on a mode in which the scanning unit executes a plurality of document exposure scans, that is, multiple copies are executed while changing various conditions such as charging conditions, exposure conditions, and development conditions of the photosensitive drum 9 (14). end.

As shown in FIG. 1, after determining the document type of the document 2 placed on the document table glass 3, for example, an image sensor is installed on the optical path of the optical image, and photographic area data is extracted from the density level. However, if the controller 12 controls the spot exposure with a laser beam from the laser light source section 7 based on this photographic area data, the designation of the photographic area can be omitted.

FIG. 5 is a flowchart illustrating an example of a photo mode recognition setting processing procedure according to the present invention.

Note that (1) to (5) indicate each step.

First, the controller 12 determines whether a photo mode key for setting a photo mode is pressed.1)
If No, the normal image sequence is executed 2), and the process ends.

On the other hand, if the determination in step (1) is YES, the scanning unit prescans the document 2 (3), extracts the photo area data of the document 2, and (4) stores the photo area data in the internal memory. (5), and the process proceeds to step (3) and subsequent steps in the flowchart shown in FIG.

(Effects of the Invention) As explained above, the present invention includes a digital scanning unit that scans and exposes a photoreceptor to an arbitrary position with a light beam based on a predetermined digital signal in parallel with the scanning of the original by the scanning unit; 1st for the image. a photo mode setting means for setting a second photo original copy mode; and a first photo document copying mode set by the photo mode setting means. Alternatively, the digital scanning unit and the exposure control means for controlling the parallel exposure scanning of the photoreceptor by the scanning unit based on the second photographic original copying mode are provided, so that only one electrostatic photographic process can be performed. Copy images can be obtained for full-page photographic originals and composite originals consisting of text and photographs.

This eliminates the need for multiple exposures and transfer processes as in the prior art, and it is possible to significantly improve copy image processing efficiency for full-page photographic originals and composite originals consisting of text and photographs.

Further, an area setting means for setting a photo area of the document image;
Since a mode setting control means is provided that prioritizes the second photo original copy mode based on the photo area setting state by the area setting means, the troublesome photo copy mode setting process is reduced and the operation is simple and error-free. You can set the optimal photo copy mode. Therefore, paper waste and the like due to photo copy mode settings can be significantly reduced.

Furthermore, the first . The second photographic original copying mode and this first. mode selection means for selectively selecting an arbitrary photo mode from a plurality of photo original copy modes different from the second photo original copy mode; and a process control means for controlling image processing conditions for the first photographic original copying mode, image formation can be performed on an original image that is not suitable for the first photographic original copying mode while arbitrarily selecting another photographic original copying mode, It is possible to always obtain an appropriate copy image according to the original image condition. Therefore, an excellent effect can be achieved in that image formation can be carried out in response to various needs of photographic originals.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an image forming apparatus showing an embodiment of the present invention, FIG. 2 is a plan view illustrating an example of the operation panel of the image forming apparatus shown in FIG. 1, and FIG. 3 is a composite original document. 4 is a flowchart illustrating an example of a photo mode setting process according to the present invention; FIG. 5 is a flowchart illustrating an example of a photo mode recognition process according to the present invention; FIGS. Figure 7 is a characteristic diagram showing the relative relationship between original density and copy density, Figure 8 is a characteristic diagram explaining the primary charging state of the photoconductor, and Figure 9 is a characteristic diagram explaining the mesh charging state of the photoconductor. be. In the figure, 1 is an original pressure plate, 2 is an original, 3 is an original table glass 3.
4 is a document illumination lamp, 58 to 5f are mirrors, 6 is an optical lens, 7 is a laser light source section, 8 is a folding mirror, 9 is a photosensitive drum, and 12 is a controller. Figure 2 Figure 3 4.1 Figure 5! Figure 4 Step (3) Figure 6 Figure 7. −Original density

Claims (3)

[Claims] (1) An image that has a scanning unit that forms an image on a photoreceptor with the reflected light of the original image that is scan-exposed, and that forms a copy image by developing and transferring the latent image formed on the photoreceptor by the scanning unit. In the forming apparatus, a digital scanning unit scans and exposes an arbitrary position of the photoreceptor with a light beam based on a predetermined digital signal in parallel with the scanning of the original by the scanning unit; a photo mode setting means for setting a photo original copy mode of the photo original;
and an exposure control means for controlling parallel exposure scanning of the photoreceptor by the digital scanning unit and the scanning unit based on the first or second photo original copying mode set by the photo mode setting means. Features of the image forming device. (2) area setting means for setting a photographic area of a document image;
2. The image forming apparatus according to claim 1, further comprising mode setting control means for preferentially setting the second photo original copying mode based on the photographic area setting state by the area setting means. (3) A mode in which an arbitrary photo mode is selectively selected from the first and second photo original copy modes for the original image and a plurality of photo original copy modes different from the first and second photo original copy modes. The image forming apparatus according to claim 1, further comprising a selection means and a process control means for controlling image processing conditions on the photoreceptor based on an arbitrary photographic mode selected by the mode selection means. Device.