JPH10136171A - Magnification controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the operating convenience of the user in the case of magnification through fine-adjustment of it in a step of e.g. 0.1% or below. SOLUTION: Each of 'fine-adjustment zoom mode' and 'magnification correction mode' is selected on a menu of an LCD, the user controls a display menu of the LCD to allow a system controller 302 to generate a magnification adjustment signal of 0.1% step, and the system controller 302 gives magnification adjustment data to a write drive control circuit 504. The write drive control circuit 504 and a laser driver circuit 502 both change number of revolutions of a polygon mirror and a write clock of a laser diode 503 based on the magnification adjustment data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a digital copying machine,
The present invention relates to a magnification control device for scaling an image in a facsimile, a printer, or the like.

[0002]

2. Description of the Related Art In a digital copying machine of an analog or digital system, a scaling step is generally 1%. The scaling method of 1% step is as follows: Dimension input scaling (when the length of the original and the length to be copied are specified, calculate the scaling and scale in 1% steps) Fixed magnification (JIS 100%, 86%, 82%, 71%, 50%, 25 used for zooming between A and B sizes
%, 115%, 122%, 141%, 200%, 400
%) Zoom magnification (magnification can be selected in 1% steps, 376 steps if the magnification range is 25 to 400%) Paper designated magnification (When the paper size is selected, the document size is detected. It is known that the magnification is changed and the magnification is changed in 1% steps).

A conventional method for finely adjusting the magnification in 0.1% steps is disclosed in, for example, JP-A-60-120658.
As described in Japanese Patent Application Laid-Open No. 62-161270, a method of minutely changing the rotation speed of a polygon mirror and a reference clock for writing at the time of writing to a photoreceptor, a method of thinning out the main scanning direction by an image processing unit (reduction of the size) Case), the inflating (in the case of enlargement) is enlarged to 0.1%, and the speed control of the scanner is set to 0.1 in the sub-scanning direction.
A method of increasing the accuracy to the unit of% is known. In the latter method, the burden on the image processing unit is greater than in the former method, the number of peripheral circuits increases, and the accuracy and resolution of the scanner need to be improved. Therefore, the former method is generally used.

[0004]

SUMMARY OF THE INVENTION However, 0.1
As a method of performing fine adjustment in the% step, a method of performing fine adjustment regardless of the magnification at the time of writing to the photosensitive member (hereinafter, “magnification correction”) and a method of performing fine adjustment according to the copy magnification (hereinafter, “zoom”) Zoom "," Fine zoom ")
Then the actual magnification is different.

[0005] For example, when performing a 400% magnification change, if a fine adjustment of + 0.1% is performed by "magnification correction" at the time of writing,
The magnification for the document is 4 (1 + 0.001) × 100% = 400.4%. On the other hand, in the “zoom magnification”, since the original is used as a reference, an increase of 0.1% results in 400.1%. Similarly, an increase of 0.1% at the time of writing is equivalent to 4
04%. Conversely, in the case of reduction, for example, at 50% magnification, it becomes 0.5 (1 + 0.001) × 100% = 50.05%, but at “zoom magnification”, it becomes 50.1%.

Considering this operationally, the following two cases can be considered.

If the length of the document to be enlarged or reduced is known and the size after the enlargement or reduction is known, "zoom magnification" is performed. Thereby, the fraction of the magnification can be absorbed to one decimal place.

A3 → A4 (71%), A3 → A5 (50%), A4 used for zooming between AB sizes of JIS
If the image is copied once at a predetermined fixed magnification such as → B5 (86%), B4 → A4 (82%), etc.
The dimensions after the copy are measured, the "correction magnification value" is obtained by comparing the dimensions with the desired dimensions, and the copy is performed again. For example, when copying is performed at 50%, when 300 mm is reduced to 149 mm, the correction is + 0.7% because 300 × 0.5 / 149 ≒ 1.007. In this case, "magnification correction" is easy to use, and there is no need to measure the dimensions on the document.

When calculating the magnification by inputting the sizes of the original and the paper in the dimension input magnification mode, fractions are generated depending on the input numerical values, but fractions of 1% or less are rounded off by rounding. The work of fitting a fine figure, table, or the like into a place of a predetermined size cannot be performed accurately. For example, a figure with a length of 190 mm is 115 m
When the size is reduced to m, 115/190 = 0.6053. However, only 61% or 60% can be selected by the 1% step scaling method.
% Is 114 mm, and a shift of 1 mm occurs. In addition, this error becomes larger as the line length becomes longer. Here, when the fine adjustment mode of “zoom magnification” or “magnification correction” is combined, the error can be reduced to about 0.1 mm.

[0010] Even in the case of fixed magnification change, in a digital copying machine of 1% step, fractions of 1% or less are rounded, so that magnification cannot be accurately changed. For example, when A3 is reduced to A4, actually 1/2 ^1/2 ≒ 0.7071, but since it is rounded to 71%, an error of 0.3% occurs. Also, when A4 is expanded to A3, actually 2 ^1/2 １４２1.4142, but since it is rounded to 141%, an error of 0.4% occurs. When A4 is reduced to B5, (1.5 / 2) ^1/2 ≒ 0.866 is actually obtained, but since it is rounded to 86%, an error of 0.6% occurs. The error can be reduced by complementing the fraction in the “zoom magnification mode” and the “magnification correction mode”.

The present invention has been made in view of the above problems, and has a
It is an object of the present invention to provide a magnification control device which is easy to use for a user when the magnification is fine-adjusted in a fine magnification step of less than%.

[0012]

In order to achieve the above object, the first means is a first magnification means for scaling an image at a relatively coarse magnification step, a rotation speed of a polygon mirror and a writing reference clock. First scaling means for changing the frequency in a smaller scale step than the first scaling means by changing the frequency at every fixed step independently of the copying magnification;
A second scaling means for changing the rotation speed of the polygon mirror and the writing reference clock frequency for each 1 / M (M is a copying magnification) step so as to change the magnification in finer steps than the first scaling means; Selecting means for selecting a second or third scaling means by a user.

[0013] The second means is the first means, wherein the first scaling means has a plurality of scaling modes for scaling at relatively coarse magnification steps, and further, among the plurality of scaling modes. The second or third mode when a specific mode is selected.
Control means for automatically selecting the magnification changing means.

A third means is that, in the second mode, when the length of the original and the length to be copied are designated, the specific mode calculates the magnification and changes the magnification in a relatively coarse magnification step. Mode.

The fourth means is characterized in that in the second and third means, the specific mode is a mode in which when a fixed magnification is designated, the magnification is changed in a relatively coarse magnification step.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a digital copying machine to which an embodiment of a magnification control device according to the present invention is applied, FIG. 2 is a block diagram showing a scanner of FIG. 1, FIG. 3 is a block diagram showing a laser writing system, and FIG. 4 is a block diagram showing the copying apparatus of FIG. 1, FIG. 5 is a block diagram showing the operation panel of FIG. 1, and FIG.
Is an explanatory view showing the display screen of the LCD in FIG. 5, FIGS. 7 and 8.
FIG. 9 is an explanatory diagram showing the rotation speed of the polygon mirror and the write clock frequency at the time of fine adjustment magnification change. FIG. 9 is a block diagram showing an example of a write clock frequency generation circuit. FIG. 10 shows another example of the write clock frequency generation circuit. Block Diagram,
FIG. 11 is a graph showing the control voltage of the VCO of FIG. 9 and the fine adjustment magnification data.

Referring to FIG. 1, this copying machine schematically shows a reading device (scanner) 1 for reading image data of a document.
00, and a copying apparatus 200 for copying image data read by the scanner 100 onto paper. The copying apparatus 200 generally includes an image memory 300 for storing image data read by the scanner 100, a copying apparatus (printer) 500 for copying image data read from the image memory 300 onto recording paper, and an operator. An operation device 400 is provided for setting various copy modes and the like, and for performing various displays to an operator.

The image memory 300 includes an image memory unit 301
And a system control device 302 for controlling the entire copying machine, in particular, for changing the magnification.
01 and an operation panel 402 as shown in FIGS. The copying apparatus 500 includes a line driver circuit 501, a laser driver circuit 502, and an LD (laser diode).
503, a writing control circuit 504, and a driving device 505 for driving a laser writing system as shown in FIG. 3 or an electrophotographic process mechanism as shown in FIG. The system control device 302 controls the read control circuit 106, the write control circuit 504, and the operation control circuit 401, respectively.
Serial data transmission is performed via signal lines L1, L2, and L3 of the RS422 standard.

The scanner 100 shown in FIG. 2 is, for example, an original moving type, and an original is conveyed on a contact glass 2 by a conveying roller pair 1 with reference to the center. The original surface on the contact glass 2 is illuminated by the light source 4, and the reflected light is imaged by the lens 5 and converted by the CCD 6 into an analog image signal.

The signal output from the CCD 6 is shown in FIG.
As shown in (1), under the control of the synchronization control circuit 105 and the read control circuit 106, the data is amplified by the amplification circuit 101 and then converted into digital image data by the A / D conversion circuit 102. This image data is corrected by the shading correction circuit 103 for unevenness in the sensitivity of the CCD 6, the uneven light amount of the light source 4 and the light amount distribution error of the lens 5. After the image processing of
Is forwarded to

The image data read from the image memory unit 301 is supplied to a line driver circuit 501 having a toggle buffer under the control of the write drive control circuit 504,
The light is transferred to the LD 503 via the laser driver circuit 502, and the light emitted from the LD 503 is modulated in accordance with the image data so that a portion having a low density is weak and a portion having a high density is strong.

In the laser writing system, as shown in detail in FIG.
Is deflected at a constant angular velocity, and the tilt of the lens is corrected by the cylindrical lens 12.
, And is reflected by the first mirror 14, the second mirror 15, and the third mirror 15 as shown in FIG. A latent image is formed on the body drum 17. At this time, the light emitted from the LD 503 is
07, is received by the synchronization detection element 508, and a synchronization detection signal in the main scanning direction is generated.

Here, in the laser writing system, the polygon mirror 11 is rotated by the polygon motor 18, and the rotation speed of the polygon motor 18 is controlled by the writing drive control circuit 504 and the rotation control circuit 506. In addition, LD503
Is controlled by the laser driver circuit 502.

In FIG. 4, the latent image on the photosensitive drum 17 is developed by a developing unit 20 with toner, and the toner image is transferred to a sheet by a transfer unit 25. The sheet is set in advance in the form of a roll sheet 21, and is fed by a feed roller 22. This paper is cut by a cutter 23 to an appropriate length, and then conveyed by a registration roller 24 so as to match the toner image on the photosensitive drum 17. And then discharged onto the discharge tray 27.

As shown in FIG. 5, the operation panel 402
It has a general key and display as a copying machine, and in particular, a paper size key 403, a magnification display 404 in units of 1%,
Zoom up key 405 and zoom down key 406
, An enlargement key 407, a reduction key 408, and a touch panel type LCD 410 for displaying a screen as shown in FIG.

When the magnification is changed by 1% in such a configuration, the sub-scanning speed of the scanner 100 is changed in the sub-scanning direction, and the image processing circuit 104 electrically performs the main-scanning direction. Image memory unit 3
01 is a read synchronizing signal WLSY from the scanner 100
It is used to absorb a difference between NC and a synchronization signal RLSYNC obtained in synchronization with one surface of the polygon mirror 11.

Here, when the fine adjustment magnification of up to 1% is performed in 0.1% steps, the synchronization signals WLSYNC, RLSYNC are obtained.
Since the difference of C occurs by 1%, the image memory unit 301 is to absorb the difference, and does not need a capacity for one page, but needs a capacity that can sufficiently absorb the difference. For example, assume that the maximum write size is A1 and the process speed is 20
Assuming 0 mm / sec, in the case of 400 DPI, a displacement of ± 1% can be absorbed with a capacity of 25 Mbits.
The image memory unit 301 does not need to be provided unless fine adjustment magnification change of 0.1% step is performed.

The six-sided polygon mirror 11 is rotated at 31496 rpm by the polygon motor 18, and is controlled by a drive clock (1049, 869 Hz in this example) corresponding to the number of rotations from the write drive control circuit 504. The write drive control circuit 504 is configured to change this drive clock in 0.1% steps within a range of +1 to -1% based on a fine adjustment command from the system control device 302.

The write timing of the LD 503 is determined by the synchronization detection signal detected by the synchronization detection element 508. The write clock of the LD 503 is 33 MHz by the PLL circuit in the write drive control circuit 504.
And is variable up to ± 2% in 0.1% steps. Here, when the frequency of the write clock changes, the write start position changes. Therefore, the write start position is controlled so that writing is performed while being distributed to the left and right from the center of the photoconductor 17.

The 0.1% step magnification adjustment signal is generated by the system controller 302 when the user operates the display screen of the LCD 410 shown in FIGS. In this case, as shown in FIG. 6A, soft keys for “fine adjustment zoom” and “magnification correction” are displayed on the LCD 410, and when the “fine adjustment zoom key” is pressed, FIG.
As shown in the above, the specified magnification of 0.1% step and + key,
When the "key" is displayed and the "magnification correction key" is pressed, the designated magnification in the vertical (sub-scanning direction) and horizontal (main scanning direction) steps of 0.1% is set as shown in FIG. The + and-keys are displayed. This display allows the user to
The magnification can be specified in 0.1% steps in the range of 1.0 to -1.0.

When the original is set on the scanner 100 after specifying the magnification, magnification adjustment data is sent from the system controller 302 to the write drive control circuit 504, and the write drive control circuit 504 adjusts the magnification. Based on the data, the rotation speed of the polygon mirror 11 and LD5
03 are both changed.

Here, the magnification in the main scanning direction (horizontal) can be changed only by the writing clock in 0.1% steps. However, in order to change the magnification in the sub-scanning direction, the rotational speed of the polygon mirror 11 is changed. If it is changed, the scanning time per mirror changes, so the magnification in the main scanning direction is also changed by the same amount. For example, increasing the magnification in the sub-scanning direction by + 0.1% to 10
When the magnification is increased to 0.1%, the rotation speed of the polygon mirror 11 is 31496 rpm × 0.999 = 3146.504r
pm, but the magnification in the main scanning direction is also -0.1%.
Change. To cancel this, it is necessary to increase the write clock by + 0.1% and change it to 33 MHz × 1.001 = 33.033 MHz.

For example, if the sub-scanning direction is finely adjusted by + 0.5%, the main scanning direction becomes -0.5%. Therefore, if the original magnification is required, the writing clock is corrected by + 0.5%. Conversely, in order to correct the sub-scanning direction by -0.1%, it is necessary to increase the number of rotations of the polygon mirror 11, and 31496 rpm × 1.001 = 31527.496r
pm. At this time, the write clock is changed to 33 MHz / 1.001 = 32.967 MHz. This relationship is shown in FIGS.

Switching between each mode of "fine adjustment zoom" and "magnification correction" is performed on the screen of the LCD 410. When "1% magnification mode" on the upper screen is selected, "paper designation" is omitted. The screen is selectable from among “magnification”, “dimension input magnification”, “partial magnification”, and “fine adjustment”. In the “paper specification scaling” mode, the sizes of the original and the paper are sequentially input, and upon completion of the input, the magnification is calculated to the first decimal place. In this case, the mode automatically shifts to the “fine adjustment” mode.

When a "fine adjustment key" (not shown) on the LCD screen is depressed on the screen after the "paper designation scaling" is set, "fine adjustment zoom" and "magnification" are displayed as shown in FIG. The screen changes to a selectable mode. And
When each mode is selected, a screen as shown in FIGS. 6B and 6C is displayed.

At the time of "variable magnification", "fine adjustment zoom" is possible for each of the vertical and horizontal magnifications. When the enlargement key 407 and the reduction key 408 shown in FIG. 5 are depressed at the “fixed magnification”, the magnifications on the enlargement side and the reduction side are respectively selected and the screen shown in FIG. 6A is displayed. The magnification value can be finely adjusted as needed. When the “fixed magnification” is selected, a magnification of 1% and a correction magnification of the first decimal place or less are sent from the operating device 400 to the system control device 302, and then the system control device 302
Is sent to the write drive control circuit 504 to change the rotation speed of the polygon mirror 11 and the write clock frequency of the LD 503.

At the time of "fine adjustment zoom", conversion for correcting the copy magnification to 1 / M is performed with the copy magnification set to M. There are several methods for changing the number of rotations of the polygon mirror 11 and the write clock frequency of the LD 503 by 1 / M. As a write clock generation circuit, a VCO (voltage controlled oscillator) 511 as shown in FIG. And a PL cascaded in two stages as shown in FIG.
L circuits 514 and 515 are conceivable. Although a desired write clock frequency can be approximated by cascading PLL circuits in two stages as shown in FIG. 10,
An error occurs because the fraction is rounded. However, since the reference frequency of the rotation speed of the polygon mirror 11 is lower than the write clock frequency, a sufficient resolution can be obtained by the one-stage PLL circuit.

FIG. 11 shows the relationship between the control voltage of the VCO 511 shown in FIG. 9 and the magnification fine adjustment data. Here, the center value of the control voltage of the VCO 511 varies depending on the characteristics of the VCO 511, but may be about 5V. In the configuration shown in FIG.
The D / A converter 51 converts the 10-bit magnification data of ２５25%
2 to a reference voltage, and then convert this reference voltage to CP
D / A based on 5-bit fine adjustment magnification data from U
The voltage is converted into a control voltage of the VCO 511 by the converter 513. Assuming that the control center is 5 V, the output of the D / A converter 513 changes in the + and-directions around 5 V.

Note that between the D / A converters 512 and 513,
By performing amplification and level shift between the D / A converter 513 and the VCO 511 by using an operational amplifier or the like as necessary, it is possible to maintain the control center frequency (33 MHz) and change the frequency up and down. In the case of “magnification correction”, 100% magnification data is given from the CPU and fixed. Similarly, the rotation speed of the polygon mirror 11 can be finely adjusted by giving fixed magnification data of 100%.

Therefore, according to the above embodiment, 1%
Since the user can select a scaling process, “magnification correction” of 0.1%, and “fine adjustment zoom”, usability can be improved. For example, by selecting both “1% zoom magnification” and 0.1% fine adjustment magnification, “1% zoom magnification” is selected.
If the size differs from the desired size after copying once, the misalignment can be corrected by selecting "0.1% magnification correction".

[0041]

As described above, according to the first aspect of the present invention, there is provided a variable magnification process for changing the rotation speed of the polygon mirror and the writing reference clock frequency at fixed steps irrespective of the copy magnification, and Since the user can select a scaling process for changing the number of rotations of the mirror and the writing reference clock frequency for each 1 / M (M is a copy magnification) step, a user-friendly scaling operation can be realized. .

According to the second aspect of the present invention, when a specific mode is selected from a plurality of magnification modes in which magnification is performed in a relatively coarse magnification step, the magnification processing in the fine magnification step is automatically performed. Since the transition is made, a user-friendly zoom operation can be realized.

According to the third aspect of the present invention, when the length of the original and the length to be copied are designated, the magnification is calculated and the mode for changing the magnification in a relatively coarse magnification step is selected. Since the process automatically shifts to the scaling process of a fine magnification step, a user-friendly scaling operation can be realized.

According to the fourth aspect of the present invention, when a mode in which magnification is changed in a relatively coarse magnification step is selected when a fixed magnification is designated, the process automatically shifts to a magnification processing of a fine magnification step. Therefore, it is possible to realize a user-friendly zooming operation.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a digital copying machine to which an embodiment of a magnification control device according to the present invention is applied.

FIG. 2 is a configuration diagram illustrating the scanner of FIG. 1;

FIG. 3 is a configuration diagram showing a laser writing system.

FIG. 4 is a configuration diagram illustrating the copying apparatus of FIG. 1;

FIG. 5 is a configuration diagram showing an operation panel of FIG. 1;

FIG. 6 is an explanatory diagram showing a display screen of the LCD of FIG. 5;

FIG. 7 is an explanatory diagram showing the number of rotations of the polygon mirror and the write clock frequency during fine adjustment magnification change.

FIG. 8 is an explanatory diagram showing the number of rotations of the polygon mirror and the write clock frequency during fine adjustment magnification change.

FIG. 9 is a block diagram illustrating an example of a write clock frequency generation circuit.

FIG. 10 is a block diagram showing another example of the write clock frequency generation circuit.

11 is a graph showing a control voltage of the VCO of FIG. 9 and fine adjustment magnification data.

[Explanation of symbols]

 11 polygon mirror 502 laser driver circuit 503 LD (laser diode) 504 writing drive control circuit

Claims (4)

[Claims] A first magnification changing means for changing the magnification of an image at a relatively coarse magnification step; and changing the number of rotations of a polygon mirror and a writing reference clock frequency for each fixed step irrespective of a copy magnification. A first scaling means for changing the magnification in finer steps than the first scaling means, and by changing the number of revolutions of the polygon mirror and the writing reference clock frequency for each 1 / M (M is the copying magnification) step A magnification control device comprising: a second magnification unit that performs magnification at a magnification step smaller than that of the first magnification unit; and a selection unit that allows a user to select the second or third magnification unit. 2. The image forming apparatus according to claim 1, wherein the first scaling unit has a plurality of scaling modes for scaling in relatively coarse magnification steps, and further, when a specific mode is selected from the plurality of scaling modes. 2. A magnification control device according to claim 1, further comprising control means for automatically selecting said second or third magnification changing means. 3. The specific mode is a mode in which when a length of a document and a length to be copied are designated, the magnification is calculated and the magnification is changed in a relatively coarse magnification step. Item 3. The magnification control device according to Item 2. 4. The magnification control device according to claim 2, wherein the specific mode is a mode in which when a fixed magnification is designated, the magnification is changed in relatively coarse magnification steps.