JPH11261769A - Digital image copying machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a digital image copying machine that conducts magnification processing to protect an original by combining electric magnification means for selecting a subscanning direction with a conventional mechanism magnification for the magnification method in the case of reduction so that a carrying speed of the original is not too fast. SOLUTION: This digital image copying machine is provided with an image signal processor 104 that selects a prescribed image signal in the case of reducing/magnifying a read image from an image signal read by an original read means 100 in a main scanning direction, applies interpolation processing between pixels in the case of magnifying the read image in the main scanning direction and applies the processing to one column of image signals in the unit of columns, an original carrying device that moves the original at a speed corresponding to the reduction or the magnification in the main scanning direction, an operation device 400 that enters a revision instruction from a usual mode into an original protection mode, and a controller 302 that executes control including synchronization control of each means according to instruction contents. In the case that the original protection mode is entered, magnification in the subscanning direction is conducted by using both the carrying speed by the original carrying device 505 or the like and the processing by the image signal processor 104.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital image copying machine which reads an image signal of a document and outputs the read image signal as it is or after processing such as scaling.

[0002]

2. Description of the Related Art Conventionally, there has been known a copying machine which reads an image signal on a document by an image sensor such as a CCD, processes the read image signal by performing a magnification process such as enlargement or reduction, and outputs the processed image signal. In the case of ordinary office copiers, since there are many uses for book originals as well as single-sheet originals, hold a flat contact glass, place the original with the reading surface down on the upper side of the contact glass, An optical system unit including a lamp, a mirror, and the like is driven by a wire pulley on the lower side, and is read by a slit in the sub scanning direction.
Also, in the case of a wide-width copying machine that handles large-size documents such as A1 and A0, installing a platen on the copying machine that places the entire document on the contact glass increases the overall size of the apparatus. However, there is a problem that the installation place is limited due to too much, and all the components such as a housing for that purpose are enlarged, and it has not been realized from the viewpoint of cost. Further, in such a wide-width copying machine, sheet documents such as drawings are mostly used, and there is little demand for book documents. For the above-described reasons, a transport device that can read a long document such as A1 or A0 while transporting the original by a roller or the like while the reading optical system is fixed is advantageous in that the installation optical system is fixed. Used. To perform a variable-size copy with a general copying machine,
The drive speed of the photoconductor is kept constant, and the drive speed on the document reading (scanner) side is set to a speed inversely proportional to the designated magnification. Therefore, in the case of a transport device that reads an original by transporting the original with a roller or the like, since the optical system is fixed, the transport speed of the original by the roller or the like is changed according to the designated magnification. In a copying machine of a type using a transport device that reads a document by transporting the document by rollers or the like, protection of the document has not been a serious problem when the copying speed is not so high as in the related art. However, in recent years, there has been an increasing demand for higher speeds. In addition, as for the reduction and enlargement magnification, the copy size is reduced to half at first.
Although it is about 50%, which is 1% or 1/4, recently, it has been reduced to 1/8, that is, 25%, and the document conveying speed is only increasing. For example, JP-A-5-639
The invention disclosed in Japanese Patent Laid-Open No. 05-2005 discloses a method in which the driving speed of the scanner is set to a speed inversely proportional to the conversion rate, and a slow-up pattern is created so that the overshoot is reduced to the target speed. ) And linear velocity (mm /
FIG. 6 shows that S) is in inverse proportion. To further describe the case of a digital copying machine, in order to perform the above-described scaling process in reading a document, instead of the scaling process of an optical system in a conventional copying machine, a scaling process in a main scanning direction is performed. However, electrical scaling is performed to reduce or supplement the information of one line fetched into the line memory. However, mounting a frame memory or a large number of line memories in the sub-scanning direction leads to a large cost. In order to increase the magnification, the driving speed is inversely proportional to the conventional magnification, and the magnification is changed by a so-called mechanical magnification, for example, the method disclosed in Japanese Patent Laid-Open No. 5-63905.

[0003]

However, as in the case of the office copying machine described above, the automatic document feeder (A)
In a copying machine that does not use a document conveying device such as DF), even if the speed of the scanner increases, the drive unit is located inside the machine, and the document does not move. Therefore, there is no need to protect the document or protect the operator at all. However, in the case of a wide-width machine, the transport speed of the document is generally higher for the reasons described above. There was a problem that the original was torn, or a finger attached to the original was caught by the operator when the original was transported. In the present invention, in view of the above-described problem, in order to prevent the document conveyance speed from becoming too high, an electric scaling means for selecting in the sub-scanning direction is added to the conventional mechanical scaling in the scaling method at the time of reduction. It is an object of the present invention to provide a digital copying apparatus capable of performing a scaling process in combination to protect a document.

[0004]

To achieve the above object, according to the first aspect of the present invention, there is provided an illuminating means having a light source for irradiating a document with light, and a cell for detecting reflected light from the document. A document reading unit in which a plurality of photosensitive elements are arranged in a line at right angles to the document conveying direction; and a predetermined method when the read image is reduced and scaled in the main scanning direction based on an image signal read by the document reading unit. When selecting an image signal and enlarging and scaling the read image in the main scanning direction, image signal processing means capable of at least performing interpolation processing between pixels, and reducing and scaling the original in the main scanning direction. Or a document conveying means for moving at a speed adapted to the enlargement / reduction, an image forming means for forming an image from the image signal, an operation means for inputting a user's instruction content, and each of the means according to the instruction content System including synchronization control In the digital image copying apparatus, the operation unit has an input unit for inputting an instruction of a document protection mode, and the image signal processing unit converts the one line of the image signal in units of columns. It is possible to execute processing in the image signal processing means, and when the document protection mode is input, change both the conveyance speed of the document conveyance means and the processing in the image signal processing means to perform sub-scanning. It is characterized by performing magnification in the direction,
When the document protection mode is selected, the magnification process can be performed by selecting one row of image signals on a row basis so that the transport speed of the document transport means is not excessively increased. According to a second aspect of the present invention, in addition to the first aspect, in the reduction / magnification processing when the document protection mode is selected by the operation means, the transport speed of the document transport means is set to the normal mode transport speed. The image signal processing unit performs reduction / magnification in the sub-scanning direction by selecting the read one row of image signals in units of a column, and performs reduction / magnification in the sub-scanning direction. The transport speed that is increased by the double process is suppressed, and the corresponding reduction process in the sub-scanning direction is selected for one row of image signals so that a desired reduction process can be obtained by a total process of the two.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on illustrated embodiments. FIG. 1 is a block diagram showing the overall configuration of a digital copying apparatus according to an embodiment of the present invention. The copying machine includes a document reading device 100 as reading means for reading a document, a copying device 200, and an operation device 400. In the copying apparatus 200, an image signal storage device 300 as storage means for storing read document information
And a copying circuit 500 for executing a series of processes for copying the stored information onto transfer paper. The image signal storage device 300 further includes
0 and a system controller 302 provided to control the copying circuit 500. In addition, the operation device 400
Key input can be performed on the system control device 302. The other configuration shown in FIG. 1 will be described in the following description with reference to FIGS. 2 to 4 showing respective parts of the document reading apparatus 100, the copying apparatus 200, and the operation apparatus 400 in FIG.

FIG. 2 is a side view showing the structure of the original reading apparatus 100 shown in FIG. In the document reading apparatus 100, when an operator inserts a document from an insertion port of the document transport unit 3, the document is transported on the upper surface of the contact glass 2 according to rotation of the roller 1 or the like. The document being transported is irradiated with light from a fluorescent lamp 4, and the reflected light forms an image on an image sensor (hereinafter referred to as a CCD) 6 via a lens 5, and the document information is read. The original image formed on the CCD 6 is converted into an analog electric signal,
Output from This analog electric signal is synchronized with the clock output from the synchronization control circuit 105, amplified by the image amplification circuit 101, and output. Next, the A / D conversion circuit 102 converts the analog image signal amplified by the image amplification circuit 101 into a multilevel digital image signal for each pixel. The shading correction circuit 103 corrects distortion due to uneven light amount, stain on contact glass, uneven CCD sensitivity, and the like. The corrected digital image signal is converted into a digital recording image signal by the image processing circuit 104,
It is output to the image signal storage device 300 in the copying apparatus 200. In the image signal storage device 300, the above-described digitally recorded image signal is written into the image page memory unit 301. Further, the image signal written in the image page memory unit 301 is read out as appropriate, and
, And converted into infrared light by the LED head 503 via the LED write control circuit 501 and the LED driver circuit 502.

FIG. 3 is a side view showing the structure of the copying apparatus 200 shown in FIG. The charging device 26 is a so-called grid-sized scorotron charger that uniformly charges the photosensitive drum 25 to -850 °. LED head 5
03 is an array of LEDs arranged in an array.
(Self-Foc lens array) via photosensitive drum 2
5 is irradiated with LED light. When the photosensitive drum 25 is irradiated with the LED light based on the digital image signal, the charge on the surface of the photosensitive drum 25 flows to the ground of the photosensitive drum 25 and disappears due to a photoconductive phenomenon. Here, the LED is not turned on in a portion where the document density is low (the binarized signal is at the non-recording level), and is turned on in a portion where the document density is high (the binarized signal is at the recording level). As a result, on the surface of the photosensitive drum 25, the laser beam non-irradiated portion becomes-
The potential becomes 850 V, and the potential of the irradiated portion becomes about -100 V, so that an electrostatic latent image corresponding to the density of the image is formed.
The electrostatic latent image is developed by the developing unit 27. The toner in the developing unit is negatively charged by stirring, and a bias voltage of -600 V is applied, so that the toner adheres only to a portion irradiated with the laser beam. On the other hand, the transfer paper is selected from the three paper feed tables 9a, 9b, and 9c, is fed out by feed rollers 12a to 12c, is cut into a predetermined length by cutters 13a to 13c, and then is transported by a transport roller 14a. , And passes under the photosensitive drum 25 at a predetermined timing by the registration roller 24. At this time, the toner image is transferred onto the recording paper by the transfer charger 23. The recording paper is then transferred to the photosensitive drum 25
The toner is further separated by the separation charger 28, transported by the transport tank 29, and sent to the fixing unit 30, where the toner is fixed on the recording paper. The recording paper on which the toner has been fixed by the fixing unit 30 is sent to a paper discharge tray 31, and
Scarlet paper is made outside the aircraft. The cleaning unit 32 is
This is a cleaning device for removing the residual toner on the photosensitive drum 25. The system control device 302 sends a drive control signal to the printer drive control circuit 504 in accordance with the instruction content of the operation device 400, and the printer drive device 5
05 is driven at the specified speed.

FIG. 4 is a top view showing the configuration of the operation panel 420 of FIG. The operation device 400 includes an operation panel 420
And an operation control circuit 410. Operation panel 42
0 is a key for designating various functions, for example, a paper size key, a paper type designation key, a paper source designation key, a numeric keypad, a start key, a mode clear key, a stop key, a density adjustment key, an image quality adjustment key, and a variable magnification. A key, a display for displaying the number of copies, a scaling ratio, and the like, and a document insertion enable display are provided. Further, a document protection key 421 for suppressing the document conveyance speed and reducing the pain of the document is provided. The operation control circuit 410 performs general operation control of the operation panel 420, and controls the operation panel 420 and the system control device 302.
Since only signal transmission is performed between them, detailed description is omitted.

Next, FIG. 5 shows the image processing circuit 104 of FIG.
3 is a diagram illustrating an embodiment of a sub-scanning magnification control circuit in FIG. The image processing circuit 104 in FIG. 1 in FIG. 5 processes the image signal sent from the preceding shading correction circuit 103 (MTF / smoothing filter, character / photo mode processing, editing / processing processing, image quality processing, After performing a scaling process, etc., the image is output to the image memory unit at the next stage. The input buffer 511 receives the image signal, the image clock, and the synchronization signal of the nth line and the (n + 1) th line, and shapes the waveform. The line memory group 512 is an FI that temporarily stores line data.
FO memory. The selector 513 switches the line data from the line memory group 512. The output buffer 514 outputs line data to the image memory unit 301 at the next stage. Normally, the image processing circuit 104
According to the synchronization signal, each line is read by a scanner, and line data that has been subjected to image processing including image signal amplification, A / D conversion, shading correction, and main scanning magnification change is output for each line. When the document protection key 421 is pressed, the signal is sent from the CPU to the control circuit 515, the SEL signal is output from the control circuit 515, and the n + 2 line is output after the n line, and the n + 1 line is output. Works like decimating. A CPU and a control circuit 515 in FIG. 5 are circuits that execute the functions of the system control device 302 and the reading control device 106 in FIG.

FIG. 6 is a side view showing a detailed configuration of the document feeder unit 3 in FIG. In FIG.
A document table 601 is a document table which feeds a document placed downward, and a document sensor 602 detects insertion of the document. The transport rollers 1a to 1f start rotating when the document is detected by the document sensor 602, and transport the document at a predetermined speed (speed corresponding to the magnification).
1c and 1e are drive rollers to which power is applied, and 1b, 1d and 1f on the upper side are driven rollers. The contact glass 2 is a glass fitted to a document reading position in the document transport path. The pulley 603 transmits the power from the motor 604 to the transport rollers 1c and 1e via a belt. The illuminations 4 a and 4 b are two illumination lamps that illuminate the original on the contact glass 2. Guide plate 6
Reference numeral 05 guides the conveyed document. The backup roller 606 makes the conveyed document adhere to the contact glass. The registration sensor 607 is a sensor that determines the timing of reading a document. The gear 608 is a gear that transmits power from the transport roller 1c to the transport roller 1a.

FIG. 7 shows a motor 604 for conveying the original shown in FIG.
FIG. 3 is a block diagram illustrating a control device. In FIG. 7, a comparator 701 obtains a difference between a command signal input and a feedback signal from a motor. The servo amplifier 702 obtains a proportional amount and an integral amount from the output of the comparator 701. The PWM output circuit 703 performs pulse width modulation on the output of the servo amplifier. The motor 604 is a servomotor that obtains a predetermined number of rotations based on a feedback signal. Encoder 704
Is a rotary encoder that is directly connected to the motor shaft and outputs rotational position data. The frequency divider 705 is
The output from the encoder 704 is divided and input to the comparator 701. In the digital copying apparatus having the configuration of the above embodiment, for example, in the operation device 400, 25% to 10%
It is possible to input zoom magnifications of 0% to 400% and in increments of 1%. When a document is inserted, a speed command is given to the comparator 701 in FIG. 7 according to the magnification ratio input to the operation device 400 described above. The signal is sent from the CPU shown in FIG. 5 or the system control device 302 shown in FIG. 1, and in a normal case, the document is sent in the document feeder unit shown in FIG. Is transported.

Next, the operation panel 420 of the operation device 400
When the document protection key 421 is depressed, the CPU shown in FIG. 5 or the system controller 30 shown in FIG.
SEL, which is a mode switching signal from mode 2 to document protection mode
The signal is output and input to the frequency divider 705. Divider 7
In the case of the present embodiment, a comparator 701 inputs a frequency-divided output that is の of that in the normal mode. As a result, the servo motor 604 rotates so as to convey the document at a half conveyance speed. In the document protection mode in which the transport speed is half the transport speed of the normal mode, the control circuit 515 for controlling the sub-scanning magnification in FIG. 5 also outputs the data thinned out line by line in response to the SEL signal. I do. By performing the above-described processing, even in the document protection mode with a 1/2 conveyance speed, an image signal output at the same magnification as the normal mode is output as an output image.
In the present embodiment, the document conveying speed is set to 1/2, and the processing of the control circuit 515 is also thinned out line by line. However, for example, the document conveying speed is reduced to 1/4 by the same method of the present invention.
The processing of the control circuit 515 can also select one line from the four lines at a predetermined cycle.

[0013]

As described above, according to the present invention, in addition to the mechanical zooming in which the conveying speed is inversely proportional to the conventional zooming ratio, the electrical zooming in the sub-scanning direction is added to the zooming method. It is possible to switch between the normal mechanical scaling only process and the combination of both scaling processes, so that even if the conventional scaling is performed, it is possible to protect the original and protect the operator's finger. It is possible to increase the width.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an overall configuration of a digital copying apparatus according to an embodiment of the present invention.

FIG. 2 is a side view illustrating a configuration of the document reading apparatus of FIG. 1;

FIG. 3 is a side view illustrating a configuration of the copying apparatus of FIG. 1;

FIG. 4 is a top view showing a configuration of the operation panel of FIG. 1;

FIG. 5 is a diagram illustrating an embodiment of a sub-scanning scaling control circuit in the image processing circuit of FIG. 1;

FIG. 6 is a side view illustrating a detailed configuration of a document conveying unit in FIG. 2;

FIG. 7 is a block diagram showing a control device of the document conveying motor of FIG. 6;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... roller, 1a-1f ... conveyance roller, 2 *
.. Contact glass, 3 ... original transport unit,
4 ... Fluorescent lamp, 5 ... Lens, 6 ... Image sensor (CCD), 9a-c ... Paper feed table, 12a-c
... feed roller, 13a-c ... cutter, 14a-c ... transport roller, 23 ... transfer charger, 24 ... registration roller, 25 ... photosensitive drum, 26 ... electrification Apparatus, 27 ... Developing unit, 28 ... Separate charger, 29 ...
Transport tank, 30 ... Fixing unit, 31 ...
Discharge tray, 32 ... Cleaning unit, 10
0: Document reading device, 101: Image amplification circuit
102: A / D conversion circuit, 103: Shading correction circuit, 104: Image processing circuit, 105
... Synchronization control circuit, 106 ... Read control circuit,
200: copying apparatus, 300: image information storage device, 301: image page memory unit, 302:
System controller 400, operation device 410
... operation control device, 420 ... operation panel, 42
1: Document protection key, 500: Copy circuit, 501
... LED write control circuit, 502 ... LED driver circuit, 503 ... LED head, 504 ...
Printer drive control circuit, 505 ... drive device, 51
DESCRIPTION OF SYMBOLS 1 ... input buffer, 512 ... line memory group, 513 ... selector, 514 ... output buffer, 515 ... control circuit, 601 ... original plate, 60
2 ... Original sensor, 603 ... Pulley, 604
.. Motors, 605 ... Guide plates, 606 ...
Backup roller, 607: resist sensor,
608 ... gear, 701 ... comparator, 702
..Servo amplifier, 703... PWM output circuit, 7
04 ... encoder, 705 ... frequency divider

Claims (2)

[Claims] An illumination unit having a light source for irradiating the original with light; and a document reading unit in which photosensitive elements in units of cells for detecting reflected light from the original are arranged in a row at right angles to a direction in which the original is transported. A predetermined image signal is selected when the read image is reduced / magnified in the main scanning direction from the image signal read by the original reading means, and when the read image is enlarged / magnified in the main scanning direction. Image signal processing means capable of at least performing interpolation processing between pixels; document transport means for moving the document at a speed adapted to reduction or enlargement in the main scanning direction; and A digital image copying apparatus comprising: an image forming means for forming an image based on the information; an operation means for inputting an instruction content of an operator; and a control means for performing control including synchronization control of the respective means in accordance with the instruction content. You The operation means may include an input means for inputting an instruction of a document protection mode, and the image signal processing means may execute the processing in the image signal processing means for the one row of image signals on a column basis. When the document protection mode is input, both the transport speed of the document transport unit and the processing in the image signal processing unit are changed to perform magnification in the sub-scanning direction. Digital image copying machine. 2. The image signal processing unit according to claim 2, wherein in the reduction / magnification process when the document protection mode is selected by the operation unit, the document speed is conveyed at a speed lower than that of a normal mode. Is the 1
2. The digital image copying apparatus according to claim 1, wherein reduction / magnification is performed in the sub-scanning direction by selecting image signals of columns in units of columns.