JPH0743715Y2 - Magnification copying machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an electrophotographic copying machine capable of variable-magnification copying, and more particularly to a position storage device for storing the position of an imaging lens to be moved at the time of variable magnification.

[Prior art]

In addition to fixed magnifications such as 1.2 times and 0.8 times, so-called zoom magnification / magnification devices that can set the magnification in 1% steps in the range of 0.7 times to 1.2 times have become common in electrophotographic copying machines that can perform variable magnification copying. ing. In the zoom variable power device, the position of the imaging lens is moved by a pulse motor or the like so that the magnification can be set in 1% steps as described above. As an example of such a device, there is a device disclosed in JP-A-60-250339. Since the zoom variable magnification device does not have a lens position sensor for each magnification, for example, a lens position sensor is provided at a position of equal magnification and this sensor is always used to set the same magnification when the power of the device is turned on.

[Problems of conventional technology]

However, in the zoom variable magnification apparatus as described above, the power is always set to the same size. Therefore, for example, in OFF EAS for copying only with a specific magnification, the magnification must be set each time the power is turned on. I have to.

Further, even when the device is produced, it is necessary to attach the lens position sensor at an appropriate position after performing the focus adjustment at the same magnification, which greatly deteriorates the productivity.

[Purpose of device]

In view of the above problems, the present invention maintains the magnification when the power is turned off even when the power is turned on in the zoom variable magnification copying apparatus,
It is another object of the present invention to provide a variable magnification copying apparatus that does not require a lens position sensor.

[Key points of device]

In order to achieve the above object, the present invention provides a variable magnification copying apparatus which performs variable magnification copying by moving a position of an imaging lens and changing a relative speed between a document and a photoconductor. A first switch for instructing to move the imaging lens and a second switch for instructing to move the imaging lens in a second direction opposite to the first direction in response to a manual input.
Moving means for moving the imaging lens in the first direction and the second direction according to a pulse signal output from the movement control means based on the instructions of the switch and the first switch and the second switch. Storage instruction means for storing the position of the imaging lens moved based on an operation instruction of the first switch and the second switch in a non-volatile storage means, setting means for setting a magnification, A control means for moving the imaging lens to a position according to the set magnification by the moving means, and storing the position information of the imaging lens in the non-volatile storage means each time the pulse signal is output. It is characterized by having.

[Example of device]

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 2 is a schematic diagram of a variable power optical system. In the figure, reference numeral 1 denotes a document glass, on which a document is placed and moved in the direction of arrow A at a predetermined speed for scanning exposure. Reference numerals 2 to 5 denote reflection mirrors, which are photoconductors 6 for rotating the image of the document in the direction of arrow B
Project to. Reference numeral 7 denotes a zoom lens having a variable focal length, which is located in the middle of the distance O-I between the document position O on the document glass 1 and the image forming position I on the photoconductor 6 during copying at the same magnification. The zoom lens 7 is moved in the direction indicated by 7A during enlargement copying, and is moved in the direction indicated by 7B during reduction copying. Now, the distance between the document position O and the lens principal point is a, the distance between the lens principal point and the image forming position I is b, the moving speed of the document glass 1 is V _A , the peripheral speed of the photoconductor 6 is V _B , and the magnification is m. Then, these relationships are shown by the following equations.

1 / a + 1 / b = 1 / f (1) m = b / a (2) V _A = V _B / m (3) (where f is the focal length of the zoom lens 7) When the magnification m is specified, a, b, and f must be changed to values that satisfy the above equations (1) and (2). Table 1 shows the above m, a, b, and f for each 5% magnification of 0.7 to 1.2 times in the case of using a lens having an O-I of 936 mm and a focal length f of 234 mm at the same magnification.

In Table 1, a ₀ is the distance between the document position O and the lens principal point at the same magnification, that is, 468 mm, and a-a ₀ shows the movement amount of the zoom lens 7 with respect to the same magnification position. + In Fig. 2
The amount of movement in the direction of 7A (enlargement) and-in the direction of 7B (reduction).

FIG. 3 shows a moving device of the zoom lens 7.
The mechanism for changing the focal length is omitted. In the figure, the zoom lens 7 is fixed to a mount 9 by a fixing band 8. The gantry 9 is configured to be movable around a sliding shaft 10 as a guide shaft, and the sliding shaft 10 is fixed to the apparatus main body by bearings 11 and 11. Screws of 0.5 mm pitch are formed on the other side of the pedestal 9, and are screwed with a drive shaft 12 having screws of 0.5 mm pitch similarly formed on the outer circumference. The drive shaft 12 is connected to the shaft of a motor 13, and is supported by a bearing 14 so as to be rotatable and immovable in the longitudinal direction of the shaft.

The screw is a right-hand screw, and by rotating the drive shaft 12 in the R direction shown in the figure, the zoom lens 7 is moved in the reduction direction (7B direction in FIG. 2), and by rotating in the E direction shown in the figure, the enlargement direction (7A direction in the same figure). ) To. In addition, forward rotation in the R direction,
The E direction is defined as reverse rotation.

The motor 13 is a pulse motor, and the input of 5 pulses is 1
It is configured to rotate. Therefore, when the motor 13 receives one pulse input, the lens 7 moves 0.1 mm in relation to the screw pitch.

FIG. 1 shows a movement control circuit of the zoom lens 7. In the figure, reference numeral 15 denotes a CPU, which controls movement of the zoom lens 7,
Circuits that control the entire copying machine but are not related to the present invention are omitted. Reference numeral 16 denotes various operation keys provided on an operation panel (not shown), including a ten key for setting a magnification. The operator sets the magnification in percent with the ten keys. The currently set magnification and the newly set magnification are displayed on the display 17 to inform the operator. Reference numerals 18, 19, and 20 denote RAM, ROM, and EEPROM, respectively, which store various data for changing the magnification, which will be described later in detail. S ₁ is a switch for rotating the motor 13 in the forward direction, and the motor 13 makes 1/5 rotations each time it is pressed. Further, S ₂ is a switch for rotating the motor 13 in the reverse direction, and each time the switch is pressed, the motor 13 similarly rotates 1/5. S ₃ is a switch operated when focus adjustment is completed, and the CPU 15 recognizes that the zoom lens 7 is at the same magnification position by the input of the port I ₂ . When the output of port 0 ₀ is high (H), the motor control unit 21
Rotate 13 forward and reverse when low (L). Port 0 ₁
A pulse signal for rotating the motor 13 is output from the motor 13, and the motor 13 rotates 1/5 per pulse as described above.

Next, Table 1 shows the data for each magnification value stored in ROM19.
The same as 5%.

Table 2 shows the magnification from 0.7 times (70%) to 1.2 times (120%) 1
ROM address and ROM when changing in 51 steps in%
It shows the relationship of data (all decimal numbers). That is, when the magnification of 120% is specified by the numeric keypad, the CPU 50 specifies the address 50 of the ROM 19 and the ROM data 125.
Read 1 The ROM data stores the numerical values obtained by the following formulas with respect to the numerical values aa ₀ shown in Table 1.

ROM data = {(a−a ₀ ) +82.6} × 10 (4) That is, the ROM data of 0.7 times is set to zero, and the numerical value is 1 for each distance required to move the zoom lens 7 by 0.1 mm thereafter. Is added. For example, in Table 1, the moving distance of the zoom lens 7 between 0.7 times and 0.75 times is -66.9-(-82.6) =
Since it is 15.7 mm, ROM is 5 for ROM address 5
The data 157 is stored.

In the above configuration, the initial setting method at the time of factory production will be described first. The lens 7 is
It must be located at the center of the document position O and the image formation position I. However, since there is some variation in the O-I distance or the focal length of the lens 7, it is necessary to finely move the lens 7 to determine the position of the lens 7 while actually confirming the focus and the magnification. Therefore, S ₁ or S ₂ is operated to finely move the lens 7 to adjust the focus and the magnification. When the focus and magnification adjustment are completed, pressing S ₃ writes the ROM data 826 of equal size shown in Table 2 to the EEPROM.

Next, the magnification setting operation will be described with reference to the flowchart of FIG. First, when the power of the device is turned on (ST1), the data of EEPROM 20 is written in the area of RAM 18 (ST2). Data 826 is the same size when the power is turned on for the first time after shipment from the factory.
Is written. Next, when the magnification is specified in ST3 C
PU15 specifies ROM address for magnification shown in Table 2 and ROM
Write the data to area 2 of RAM18. If 0.75 times is specified, the CPU 15 specifies the address 5 of the ROM 19 and writes the ROM data 157 in the area 2 of the RAM 18. Next, in ST5, the data in area 2 of RAM 18 is subtracted from the data in area 1 of RAM 18. In the above case, 826−157 = + 669. S
T6 determines whether or not the result of ST5 is zero. If it is zero, it means that the same magnification as the magnification currently set has been designated, and the processing returns to ST3. In ST7, the positive / negative judgment of ST5 is performed to judge whether the motor 13 is rotated normally or reversely. In the above case, it is positive because it is +669 (S
T7 is Y) At ST8, the port O _{0 is set} to H, and the motor control unit 21 is instructed to rotate the motor 13 in the forward direction. That is, the motor control unit 21 controls to move the lens 7 in the reduction direction. If ST5 is negative, ST7 is N and the port O _{0 is set} to L to control the lens 7 to move in the magnification direction. In ST10 and ST11, the pulse of the absolute value of the result calculated by ST5 from port O ₁ is output. That is, 669 pulses are output and the motor 7 outputs 669 ÷
5 = 133.8 rotation forward rotation, and the lens 7 moves in the reduction direction of 669 × 0.1 = 66.9 mm. It is needless to say that this movement amount is 0-(-66.9) = 66.9 mm as shown by aa ₀ of 1x and 0.75x in Table 1. When the output of 669 pulses is completed, the motor 1
3 stops (ST13), RAM18 area 2 data (157)
Is written to EEPROM (ST14), and is similarly written to area 1 of RAM18 (ST15). It should be noted that although the display of the magnification is omitted in the flowchart, it may be performed at an appropriate place in the flow, for example, immediately after ST2, ST4, or ST13.

Since the magnification data is stored in the EEPROM 20 after the magnification setting is completed, the magnification data does not disappear even when the power of the device is cut off, and the magnification before the cutoff can be maintained even when the power is turned on again. If data is written to the EEPROM 20 each time one pulse is output in ST10, the position of the zoom lens 7 can be accurately confirmed when the power is turned off even if the power is shut off while the zoom lens 7 is moving. Alternatively, if RAM18 is backed up by a battery, EEPROM20 is unnecessary and the same effect can be obtained.

The present invention is not limited to the above-described embodiments, but can be applied to a zoom magnification changing mechanism using a fixed focus lens instead of the zoom lens, for example. In this case, the O-I may be changed by moving the mirror at the same time as moving the position of the lens. Further, needless to say, the present invention can be applied to not only the movement of the document table but also the movement of the optical system. Further, if the control of the motor 13 is the closed control using the encoder, the positional accuracy becomes more accurate. Further, a unity return switch may be provided, and when the switch is turned on, the unit may be set to the same size when the power is turned on and left to the user to select.

[Effect of device]

As described in detail above, according to the variable magnification copying apparatus of the present invention, it is possible to maintain the magnification before power-off without having to return to the same magnification even when the power source of the zoom variable magnification copying machine is turned on. Further, since the lens position sensor of the optical system is unnecessary, the mechanism is simple and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a zoom lens movement control circuit diagram of the present invention, FIG. 2 is a schematic view of a unity magnification optical system, FIG. 3 is a view showing a zoom lens moving device, and FIG. 4 is a zoom lens movement flowchart. is there. 6 ... Photoreceptor, 7 ... Zoom lens, 9 ... Stand, 12 ...
… Drive axis, 13 …… Motor, 15 …… CPU, 16 …… Operation key, 18 …… RAM, 19 …… ROM, 20 …… EEPROM, 21 …… Motor control section.

Claims (1)

[Scope of utility model registration request] 1. A variable-magnification copying apparatus for performing variable-magnification copying by moving the position of an imaging lens and changing the relative speed of a document and a photoconductor, and an instruction to move the imaging lens in a first direction in accordance with a manual input. A first switch for performing the operation, a second switch for instructing to move the imaging lens in a second direction opposite to the first direction according to a manual input, the first switch and the second switch Moving means for moving the imaging lens in the first direction and the second direction in accordance with a pulse signal output from the movement control means based on the instruction of the switch, and the first switch and the second switch. Storage instruction means for storing the position of the imaging lens moved based on the operation instruction in the non-volatile storage means, setting means for setting a magnification, and the imaging at a position according to the set magnification. The lens is moved by said moving means,
And a control means for storing the position information of the imaging lens in the non-volatile storage means each time the pulse signal is output.