JPH0537780A - Image forming device - Google Patents

Abstract

PURPOSE:To obtain a copy with fidelity to an original without need of depression of a key designating a photograph original without being affected of the presence of glitter of the original. CONSTITUTION:An original is read by a photoelectric converter 11 and an A/D converter 91 or the like to generate a picture data and a print picture data is generated based on the picture data, then a glitter detector 19 detects the glitter of the original. Whether the original is a photograph original or a plastic laminated sheet or the like is detected based on the glitter and a proper gamma processing parameter is set to implement gamma processing correction to the picture data.

Description

Detailed Description of the Invention

 [Object of the Invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus, especially a digital image forming apparatus (digital copying machine), for forming an image on various originals having different gloss amounts.

[0002]

2. Description of the Related Art In a digital copying machine, an original is illuminated obliquely by an exposure lamp and an image of the original is formed on a photoelectric conversion element by a mirror and a lens. For example, an original having a glossy surface such as a photographic original is imaged. When copying, the amount of direct reflection components on the surface of the original increases and the copy is made dark. For this reason, the conventional digital copying machine is provided with a key for designating a photographic original, and when this key is pressed, the image processing parameters are set so that the copy is brighter than when a normal original is copied. It was

[0003]

However, although a manuscript in which a plain paper is laminated with a plastic sheet is as glossy as a photographic manuscript, it is not called a photographic manuscript. For this reason, with respect to this original, the key designating the original as a photograph is rarely pressed, and the original mode is often used for copying. As a result, there is a problem that the copy is made significantly darker than the original document.

Therefore, the present invention provides an image forming apparatus capable of obtaining a copy faithful to a document without being pressed by a key for designating a photo document without being affected by the glossiness of the document. The purpose is to [Constitution of Invention]

[0005]

To achieve this object, an image forming apparatus of the present invention comprises an image reading means for reading a document to generate image data, and an image processing from the image data generated by the image reading means. An image processing circuit that creates print data based on parameters, an image forming unit that forms an image on an image forming medium according to the image data created by the image processing circuit, a unit that detects the gloss of the original, And a control means for setting the image processing parameter of the image processing circuit based on the gloss amount detected by the detection means and outputting the set image processing parameter to the image processing circuit.

[0006]

In the image forming apparatus of the present invention, the document is read by the image reading means to generate image data, and the image processing circuit
The print data is created from the image data created by the image reading means based on the image processing parameters, and the image forming means forms an image on the image forming medium based on the image data created by the image processing circuit. The image processing parameter of the processing circuit is set based on the gloss amount detected by the gloss detecting unit.

[0007]

FIG. 2 shows a thermal transfer type color copying machine capable of selectively producing multicolor color copying as an example of the image forming apparatus of the present invention. That is, reference numeral 1 is a main body of the copying machine, and an operation panel 50 is provided on the front portion of the upper surface of the main body 1. The upper part of the main body 1 is an image reading section 3 for scanning and reading the original O set on the original table (transparent glass) 2, an image processing section 4 for processing an image read by the image reading section 3, and a lower part. Is the image forming unit 5. Reference numeral 100 denotes an original cover provided on the original table 2 so as to be openable and closable, and has an original pocket 100a. A shading correction white reference plate 31 and a document size indicator 32 are provided on the upper end surface of the document table 2.

As shown in FIGS. 2 and 3, the image reading unit 3 includes a first carriage 7 having an exposure lamp 6 as a light source, a second carriage 8 for bending an optical path by a mirror, a lens 16a and color correction. The lens section 16 provided with the filter 16b, the mirror section 10 for guiding the reflected light from the original O to the photoelectric converter 11 and correcting the optical path length at the time of zooming, the original O.
A photoelectric converter (conversion means) 11 for receiving the reflected light from the
And a drive system (not shown) for changing the position of each part.

The first carriage 7 has an exposure lamp 6 for irradiating the original O with light, a reflector 12 as a reflecting mirror for collecting the light from the exposure lamp 6 on the surface of the original, and a light radiated from the exposure lamp 6. A filter 17 for absorbing heat rays,
A mirror 13 that guides the reflected light from the document O to the second carriage 8 side is mounted.

Reference numeral 19 in the drawing denotes a gloss detector for detecting the glossiness of the original O, which is installed below the original table 2. As shown in FIG. 4, the gloss detector 19 includes one light emitting diode 19a and two phototransistors 19b and 19b.
and a light emitting diode 19
The light emitted from a is reflected on the surface of the original and is input to the phototransistors 19b and 19b having different mounting positions. A hood 19c is attached to the phototransistor so as to capture reflected light from the same place on the document surface. Since the reflection angles of the phototransistors 19b and 19b are different, if the gloss is large, the output difference between the two phototransistors becomes large, and the gloss can be determined based on the output difference.

The second carriage 8 is provided with mirrors 8a and 8b for guiding the light guided by the mirror 13 to the lens 16. The first and second carriages 7 and 8 are
The second carriage 8 is connected to each other by a timing belt (not shown) and is driven by the scanning motor 18, so that the second carriage 8 moves in the same direction at half the speed of the first carriage 7. There is. This allows scanning so that the optical path length to the lens 16a is constant. The mirror section 10 has two mirrors 10.
a, 10b, and guides the light to the photoelectric converter 11.

The photoelectric converter 11 photoelectrically converts the reflected light from the original O to convert the image of the original O into cyan,
Green and yellow (or red, green, blue) light signals are separately output as color signals, and are mainly composed of, for example, a CCD type line image sensor. In this case, one pixel of the document O corresponds to three continuous elements (C, G, Y) of the CCD sensor. The output of the photoelectric converter 11 is output to the signal processing unit 4 described later.

The image forming section 5 has a platen drum 22 arranged substantially in the center thereof. This platen drum 22
The periphery of the is formed of an elastic body such as rubber and has a function as a platen roller of the thermal head portion 24. The platen drum 22 winds the paper P by rotating in the clockwise direction so that the paper P does not shift during the overlay printing. Around the platen drum 22, pinch rollers 25a and 25b for preventing the paper P from floating above the platen drum 22 at a predetermined interval.
Is provided. The circumference of the platen drum 22 is
The length is slightly longer than the maximum paper size in the longitudinal direction.

A thermal head portion 24 is disposed on the lower left portion of the platen drum 22. The thermal head portion 24 is attached to a radiator integrally formed on the rear end surface of the holder, and the thermal printer head 24
a, heat sink 24b, pressure spring 24c, cam 24
d, and a cam switch 24e. Further, a ribbon cartridge 26 is mounted between the platen drum 22 and the thermal head portion 24 so as to interpose an ink ribbon 26a as an image forming medium.

The core of the ribbon cartridge 26 is connected to a drive shaft (not shown) of the motor through a drive force transmission mechanism (not shown) and is rotatively driven as necessary, whereby The ink ribbon 26a is a ribbon guide 26b,
Guided by 26b, it runs between the platen drum 22 and the thermal head portion 24. The ribbon cartridge 26 is slidable by a slide rail 26c. In the figure, 22a is a grip sensor, 22b is a paper width sensor, 22c is a motor for driving the platen drum, and 22d is a paper discharge scraper.

A paper feed cassette 20 is detachably attached to the lower portion of the main body 1, and a pickup roller 41a, a paper feed roller 41b, and a separation roller 41 are correspondingly attached thereto.
c, an intermediate roller 41d is arranged. The sheets P as the image forming medium accommodated in the sheet feeding cassette 20 are taken out one by one by these rollers 41a to 41d, and after the leading end alignment is performed, they are transported toward the platen drum 22 and are pinched by the pinch roller 25a. Thus, the platen drum 22 is wound around. Reference numeral 29a is a paper empty switch for detecting the presence or absence of the paper P, 29b is a paper size switch for detecting the paper size, and 29c.
Is a paper top switch that detects the leading edge of the paper, 29
d is an OH that detects whether the paper is a plastic sheet
It is a P detection switch. Reference numeral 21 is a manual feed guide for guiding the manually fed paper P.

The paper P is wound around the platen drum 22 by clockwise rotation, and after the leading edge passes through the printing area, the thermal head 24 is pressed against the platen drum 22 to perform printing.

When the printing of the first color is completed, the platen drum 22 is supposed to have rotated almost once. here,
The thermal head 24 is released once, and the ink ribbon 26
Is taken up and the next color is cued. Then, the platen drum 22 starts to rotate clockwise again, the thermal head 24 performs printing, and the next color is overprinted (printed).

Thus, in the case of full color copying,
Image formation is performed by four operations of yellow, magenta, cyan, and black, or three operations of yellow, magenta, and cyan. In the case of a single color such as black, the operation is performed once.

At the time of discharging the paper, the paper P is separated from the platen drum 22 by the paper discharge scraper 16a and is discharged onto the paper discharge tray 28 by the paper discharge rollers 27. In the figure, 27a is an exit switch.

FIG. 1 is a schematic control system block diagram of a digital image forming apparatus showing an embodiment of the present invention.
1, a first control unit 82 and a second sub control unit 83. The main controller 81 includes the gloss detector 19 and the operation panel 5
0, correction circuit 84, luminance / color difference separation circuit 85, image quality improvement circuit 86, color signal conversion circuit 87, binarization circuit 88, first sub-control unit 82, second sub-control unit 83, and control of these. Control

The first sub controller 82 is a light source controller 8
9, the motor drive unit 90, the photoelectric converter 11, the A / D converter 91, and the resolution conversion unit 92, which are connected to each other and control these. The light source controller 89 is connected to the exposure lamp 6 and controls the lighting and the light amount of the exposure lamp 6.
That is, the exposure lamp 6 is turned on during a normal image reading operation. The motor drive unit 90 drives the scanning motor 18. The second sub control unit 83 includes a thermal head temperature control unit 93 and the thermal head 3
1, various detection switches 94, and drive units 95 and 97, respectively, and control these. Driver 95
Is connected to and drives a drive system 96 such as a motor and a solenoid.

The correction circuit 84 performs shading correction on the image data (after resolution conversion) obtained by A / D conversion of the reflected light from the original O, that is, correction of variation of the photoelectric converter 11. The correction circuit 84 further performs gamma correction processing for shifting the amplitude of the image signal and converting the gradation. The gamma correction process is a correction process so that when the amplitude of the image signal is small (or large), the correction is performed so that the amplitude is suppressed to a predetermined amplitude. By this gamma correction process, the brightness of the paper P on which an image is formed is adjusted. You can Then, the correction circuit 84 outputs the red R, green G, and blue B signals in synchronization with a clock signal from an oscillator (not shown).

The color signal conversion circuit 87 receives the luminance signal (I) and the color difference signal 1 sent from the image quality improvement circuit 86.
(C1), the color difference signal 2 (C2), Y, M, C, and B are output according to the color signal selection signal from the main control unit 81.
One of the color signals is sent to the binarization circuit 88. The color signal conversion circuit 87 is composed of, for example, a ROM and outputs a color signal corresponding to an address designated by each of the signals.

The color signal conversion circuit 87 receives the luminance signal (I) and the color difference signal 1 sent from the image quality improvement circuit 86.
(C1), the color difference signal 2 (C2), and the color signal selection signal from the main controller 81.
One of Magenta M, Cyan C, or Black B
One color signal is a clock signal from an oscillator (not shown)
It is output in synchronization with the clock divided by / 3. Switching between yellow Y, magenta M, cyan C, and black B is performed by a count value obtained by counting a page synchronization signal supplied from the main controller 81 by a counter (not shown). Next, the operation of the copying machine will be described with reference to FIGS.

After setting the copying conditions, the copy key 50a
When is pressed, copying is performed according to the various copying conditions that have been set. That is, the reflected light of the light emitted from the exposure lamp 6 to the original O is imaged on the photoelectric converter 11. The photoelectric converter 11 separates the light into cyan (C), green (G), and yellow (Y) analog color signals, and sends them to the A / D converter 91. The A / D converter 91 converts each analog color signal into a digital signal and outputs the digital signal to the resolution conversion unit 92.

The resolution converter 92 performs resolution conversion so that the resolution of the photoelectric converter 11 and the resolution of the thermal head 24 match, and sends the result to the correction circuit 84. On the other hand, in the gloss detector 19, the light emitting diode 19a
The light emitted from the light source is reflected by the surface of the original and is input to the phototransistors 19b and 19b having different mounting positions.
Entered in. In the main control unit 81, the phototransistor 19
The glossiness of the original O is detected based on the output difference between b and 19b. Then, the main control unit 81 detects the presence or absence of gloss on the document surface (that is, whether it is a normal document, a photographic document, or a plastic laminated document) based on the glossiness, and the correction circuit 84 is detected according to the detection. , Send signals of appropriate gamma correction processing parameters. For example, in a photographic original or a plastic laminated original, the amplitude of the image signal obtained by reading the original surface is small, so if the image is formed as it is,
Since it becomes dark as a whole, the gamma correction processing parameter is set so that the amplitude spreads to a predetermined amplitude. Then, in the correction circuit 84, C, which is sent from the resolution conversion unit 92,
For each of the G and Y color signals, shading correction (correction of exposure distortion in the image reading unit 3, variation in sensitivity of the photoelectric conversion element, and the like) is performed on the variation in the photoelectric converter 11. Further, gamma correction processing is performed based on the set gamma processing parameter. The result is the luminance / color difference separation circuit 8
Send to 5. The luminance / color difference separation circuit 85 performs various arithmetic processes on the C, G, and Y color signals sent from the correction circuit 84, and outputs a luminance signal (I), a color difference signal 1 (C1), and a color difference signal 2 (C2). Image quality improvement circuit 86
Send to. The image quality improving circuit 86 analyzes the luminance signal, the color difference signal 1, and the color difference signal 2 sent from the luminance color difference separating circuit 85, performs image quality improving processing such as edge enhancement and character specification, and sends them to the color signal converting circuit 87. .. As a result, the color signal conversion circuit 87 performs color conversion based on the luminance signal, the color difference signal 1, and the color difference signal 2 that have been subjected to the image quality improvement processing, and according to the color selection signal from the main control unit 81, the yellow ( Y), magenta (M), cyan (C), black (B) [the three primary colors (Y, M, C) at the time of printing plus B] are converted into one color signal (a signal corresponding to the density), Binarization circuit 88
Send to. The binarization circuit 88 has one of the color signals (Y, M, C, and B) sent from the color signal conversion circuit 87.
Area gradation conversion by the dither method, that is, 2
The binarization is performed and the binarized signal is sent to the thermal head temperature controller 93 via the switching circuit 98. The thermal head temperature control unit 93 sends a print signal to the thermal head 24 based on the binarized signal supplied from the binarization circuit 88.
On the other hand, the paper P in the paper feed cassette 20 is taken out and conveyed by the pickup roller 41a, the paper feed roller 41b, the separation roller 41c, and the intermediate roller 41d. Then, the conveyed paper P is guided to the platen drum 22 and wound around the platen drum 22.

Thus, the thermal head 24 prints (that is, forms an image) on the paper P wound around the platen drum 22 according to the print signal. The obtained print is subjected to an appropriate gamma correction process in the correction circuit 84, so that a copy whose brightness is adjusted can be obtained.

In the above embodiment, the gamma processing parameter is set and switched depending on the presence or absence of gloss, but the present invention is not limited to this, and the gamma processing parameter is stepwise or continuously according to the gloss amount. May be set and switched. In this case, the brightness can be finely adjusted.

[0030]

The gamma correction processing image processing parameter is set according to the gloss amount of the original, and the image processing is performed based on the set image processing parameter. Therefore, even for glossy images, it is necessary to press a predetermined key. In addition, it is possible to obtain a copy with the brightness faithful to the original.

[Brief description of drawings]

FIG. 1 is a schematic control system block diagram of a digital image forming apparatus showing an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a digital image forming apparatus showing an embodiment of the present invention.

FIG. 3 is an operation explanatory diagram of an image reading unit of the apparatus.

FIG. 4 is a schematic configuration diagram of a gloss detection unit of the apparatus.

[Explanation of symbols]

1 ... Copier main body, 2 ... Document table, 3 ... Image reading unit, 4 ...
Image processing unit, 5 ... Image forming unit, 6 ... Exposure lamp, 7 ... First carriage, 8 ... Second carriage, 8a, 8b ... Miller, 9 ... 10 ... Miller unit, 10a, 10b ... Miller,
11 ... Photoelectric converter, 12 ... Reflector, 13 ... Mirror,
16 ... Lens part, 16a ... Lens, 16b ... Color correction filter, 17 ... Heat ray absorption filter, 18 ... Scanning motor, 19 ... Gloss detector, 20 ... Paper feed cassette, 21
... Manual feed guide, 22 ... Platen drum, 22a ... Grip sensor, 22b ... Paper width sensor, 22c ... Platen drum drive motor, 22d ... Paper discharge scraper, 24 ... Ser
Round head part, 24a ... Thermal printer head, 24
b ... heat sink, 24c ... pressure spring, 24d ... cam,
24e ... cam switch, 25a, 25b ... pinch-
La, 26 ... Ribbon cartridge, 26a ... Ink ribbon, 26b ... Ribbon guide, 26c ... Slide rail,
27 ... Paper discharge roller, 27a ... Exit switch, 28
... Paper ejection tray, 29a ... Paper empty switch,
29b ... Paper size switch, 29c ... Paper top switch, 29d ... OHP detection switch, 31 ... Shading correction white reference plate, 32 ... Original size indicator, 41a ... Pickup roller, 41b ... Paper feeding roll
La, 41c ... Separation roller, 41d ... Intermediate roller, 50 ...
Operation panel, 50a ... Switch, 81 ... Main control unit, 82
... first control unit, 83 ... second sub-control unit, 84 ... correction circuit,
85 ... Luminance color difference separation circuit, 86 ... Image quality improvement circuit, 87 ...
Color signal conversion circuit, 88 ... Binarization circuit, 89 ... Light source control section, 90 ... Motor drive section, 91 ... A / D converter, 92 ...
Resolution conversion unit, 93 ... Thermal head temperature control unit, 94
... various detection switches, 95 ... drive unit, 96 ... drive system, 1
00 ... manuscript cover, 100a ... manuscript pocket.

Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location G03G 15/04 119 9122-2H

Claims (1)

Claim: What is claimed is: 1. An image reading unit that reads an original to generate image data, and an image processing circuit that creates print data from the image data generated by the image reading unit according to image processing parameters. An image forming means for forming an image on an image forming medium based on image data created by an image processing circuit, a means for detecting gloss of a document, and the image processing circuit based on the gloss amount detected by the gloss detecting means. And a control means for outputting the set image processing parameter to the image processing circuit.